Thermal transfer printer, thermal transfer recording method and thermal transfer recording web roll

Information

  • Patent Grant
  • 6690405
  • Patent Number
    6,690,405
  • Date Filed
    Wednesday, January 22, 2003
    21 years ago
  • Date Issued
    Tuesday, February 10, 2004
    20 years ago
Abstract
A thermal transfer printer includes a thermal transfer recording web roll having a bore and obtained by rolling a thermal transfer web. The segment of the thermal transfer recording web forming the innermost layer of the thermal transfer recording web roll is fixed to a part of a segment of the same forming the second innermost layer of the thermal transfer recording web roll. A holding device is inserted in the bore of the thermal transfer recording web roll to hold the thermal transfer recording web roll. The thermal transfer recording web roll and the holding device rotate in a unit to feed the thermal transfer recording web to a thermal transfer recording unit that forms images on the thermal transfer recording web. The thermal transfer recording web roll can be prepared at a low cost without requiring much time and effort.
Description




BACKGROUND OF THE INVENTION




1. Field of the Invention




The present invention relates to a thermal transfer printer capable of simply and quickly printing a thermal transfer image of an excellent image quality without using any feed core when a roll of thermal transfer recording web (hereinafter referred to as “thermal transfer recording web roll”) is loaded into a thermal transfer printer, a thermal transfer recording method and a thermal transfer recording web roll.




2. Description of the Related Art




Various known thermal transfer recording methods use a thermal transfer sheet having a base sheet and a color transfer layer formed on the base sheet, and prints an image of a character, a figure or a pattern on a recording sheet by heating portions of the transfer color layer from behind with a thermal head or the like to transfer portions of the color transfer layer corresponding to yellow, magenta and cyan parts of the image to the recording sheet.




Known thermal transfer recording methods are classified by the type of the color transfer layer into thermal sublimation transfer recording methods and thermal melting transfer recording methods. The thermal sublimation transfer recording method uses a thermal transfer sheet formed by coating a base sheet with a transfer color layer of a binder containing sublimable dyes, heats the thermal transfer sheet from behind the same to sublimate and transfer the dyes contained in the transfer color layer to a recording sheet. The recording surface of the recording sheet is coated with a dye-recipient layer.




The thermal melting transfer recording method uses a thermal transfer sheet formed by coating a base sheet with a transfer color layer capable of being readily softened and melted by heating and of being transferred, and transfers portions of the transfer color layer to a recording sheet by heating the thermal transfer sheet from behind the same.




Both the thermal sublimation transfer recording method and the thermal melting transfer recording method are capable of forming both monochromatic images and multicolor images. The thermal transfer recording method uses a three color thermal transfer sheet to print images in three colors, i.e., yellow, magenta and cyan, or a four-color thermal transfer sheet to print images in four colors, i.e., yellow, magenta, cyan and black, and records color images on recording sheets by transferring portions of the thermal transfer sheet corresponding to parts of those colors of images to recording sheets.




The thermal transfer recording method uses thermal transfer recording sheets, i.e., recording sheets, and feeds the thermal transfer recording sheets in a stack to a printer or uses a recording web and feeds the recording web in a recording web roll to a printer.




The thermal transfer printing is applied prevalently to mass printing in recent years and rolled thermal transfer recording webs are used prevalently. Generally, the thermal transfer recording web is wound in a roll on a feed core, i.e., a feed bobbin, the leading edge of the thermal transfer recording web is attached adhesively to a take up core, i.e., a take up bobbin, to take up the thermal transfer recording web on the takeup core or portions of the thermal transfer recording web used for thermal transfer printing are cut and discharged in sheets. The rolled thermal transfer web needs a feed core. The feed core is scrapped or reused after the rolled thermal transfer recording web has been exhausted. The core must be formed in a high dimensional accuracy to roll the thermal transfer web thereon uniformly without creasing the same and hence the core is costly.




The core of a rolled thermal transfer recording web comes into contact with the members of a driving unit of a printer when the roll of the thermal transfer recording web is rotated in the printer. Therefore, when a paper tube made principally of paper pulp and less expensive than a plastic tube is used to reduce printing cost, the paper tube is abraded frictionally by the members of the driving unit into paper powder, the paper powder is scattered in the printer, and forms pinholes that reduces image quality in printed matters produced by thermal transfer printing.




Time and effort are required for purchasing and storing feed cores, loading the same to a takeup mechanism and taking up the thermal transfer recording web.




SUMMARY OF THE INVENTION




The present invention has been made in view of such problems and it is therefore an object of the present invention to provide a printer capable of simply and quickly printing a thermal transfer image of an excellent image quality without using any feed core when a roll of thermal transfer recording web is loaded into a thermal transfer printer, a thermal transfer recording method and a thermal transfer recording web roll.




According to the present invention, a thermal transfer printer includes: a thermal transfer recording web roll having a bore and obtained by rolling a thermal transfer web, in which a segment of the thermal transfer recording web forming an innermost layer of the thermal transfer recording web roll is fixed to a part of a segment of the same forming a second innermost layer of the thermal transfer recording web roll;




a rotative driving mechanism inserted in the bore of the thermal transfer recording web roll; and




a thermal transfer recording unit for recording images on the thermal transfer recording web unwound from the thermal transfer recording web roll held by the rotative driving mechanism.




In the thermal transfer printer according to the present invention, the segment of the innermost layer of the thermal transfer recording web roll excluding an inner edge part is fixed to the part of the second inner most layer, and the rotative driving mechanism includes a holding device for holding the inner edge part of the thermal transfer recording web.




In the thermal transfer printer according to the present invention, the holding device has a holding rod having a diameter substantially equal to that of the bore of the thermal transfer recording web roll, and having in its circumference with a recess for holding the inner edge part of the thermal transfer recording web.




In the thermal transfer printer according to the present invention, the holding device has a holding rod having a diameter substantially equal to that of the bore of the thermal transfer recording web roll, and having a groove to receive the inner edge part of the thermal transfer recording web.




In the thermal transfer printer according to the present invention, the holding device is provided with a pair of drive shafts for holding the inner edge part of the thermal transfer recording web.




In the thermal transfer printer according to the present invention, the rotative driving mechanism includes a pair of caps disposed on opposite end surfaces of the thermal transfer recording web roll, respectively, so as to be engaged in the bore of the thermal transfer recording web roll.




In the thermal transfer printer according to the present invention, at least one of the caps has elastic parts for applying pressure radially outward to an inner surface of the bore of the thermal transfer recording web roll.




In the thermal transfer printer according to the present invention, at least one of the caps has a flange in contact with the end surface of the thermal transfer recording web roll.




In the thermal transfer printer according to the present invention, one of the caps has elastic parts for applying pressure radially outward to an inner surface of the bore of the thermal transfer recording web roll, and the other cap has a part to be inserted into the former cap to press the elastic parts radially outward.




In the thermal transfer printer according to the present invention, each of the pair of caps is held in the bore of the thermal transfer recording web roll through a bushing provided with a slit.




In the thermal transfer printer according to the present invention, a slit is formed between the adjacent elastic parts of the cap.




In the thermal transfer printer according to the present invention, the segment of the inner end segment of the rolled thermal transfer recording web roll excluding an inner edge part is fixed to the part of the second innermost layer, and the inner edge part is inserted in the slit formed in the bushing or the slit of the cap.




In the thermal transfer printer according to the present invention, the rotative driving mechanism includes drive rollers disposed in the bore of the thermal transfer recording web roll in contact with an inner surface of the bore of the thermal transfer recording web roll.




In the thermal transfer printer according to the present invention, the rotative driving mechanism includes a pair of drive rollers, and the center distance between the pair of drive rollers is adjustable.




In the thermal transfer printer according to the present invention, the pair of drive rollers are biased away from each other.




In the thermal transfer printer according to the present invention, the drive rollers have a circumference provided with ridges or knobs.




In the thermal transfer printer according to the present invention, the rotative driving mechanism includes a plurality of drive rollers disposed in the bore of the thermal transfer recording web roll, and an endless belt extended around the plurality of drive rollers and pressed by the plurality of drive rollers so as to be in contact with an inner surface of the bore of the thermal transfer recording web roll.




In the thermal transfer printer according to the present invention, the rotative driving mechanism includes a pair of rotative driving members disposed at opposite end surfaces of the thermal transfer recording web roll and capable of applying pressure to the opposite end surfaces of the thermal transfer recording web roll.




In the thermal transfer printer according to the present invention, the pair of rotative driving members have taper side surfaces tapering toward the end surfaces of the thermal transfer recording web roll, respectively.




In the thermal transfer printer according to the present invention, the pair of rotative driving members are mounted on a center shaft inserted in the bore of the thermal transfer recording web roll.




In the thermal transfer printer according to the present invention, at least one of the pair of rotative driving members is pressed by a spring mounted on the center shaft against the end surface of the thermal transfer recording web roll.




In the thermal transfer printer according to the present invention, distance between the rotative driving members mounted on the center shaft is adjustable.




According to the present invention, a thermal transfer recording method includes the steps of: preparing a thermal transfer recording web roll having a bore and obtained by rolling a thermal transfer web, in which a segment of the thermal transfer recording web forming an innermost layer of the thermal transfer recording web roll is fixed to a part of a segment of the same forming a second innermost layer of the thermal transfer recording web roll; unwinding the thermal transfer recording web by engaging a rotative driving mechanism in the bore of the thermal transfer recording web roll and rotating the thermal transfer recording web roll by the rotative driving mechanism; and carrying out a thermal transfer recording operation to record an image on the thermal transfer recording web unwound from the thermal transfer recording web roll.




In the thermal transfer recording method according to the present invention, the segment of the innermost layer of the rolled thermal transfer recording web roll excluding an inner edge part is fixed to a part of the second innermost layer, and the thermal transfer recording web roll is driven for rotation by the rotative driving mechanism including a holding device holding the inner edge part of the thermal transfer recording web.




In the thermal transfer recording method according to the present invention, the rotative driving mechanism includes a pair of caps disposed at opposite end surfaces of the thermal transfer recording web roll, respectively, so as to be engaged in the bore of the thermal transfer recording web roll.




In the thermal transfer recording method according to the present invention, the rotative driving mechanism includes drive rollers disposed in the bore of the thermal transfer recording web roll in contact with an inner surface of the bore of the thermal transfer recording web roll.




In the thermal transfer recording method according to the present invention, the rotative driving mechanism includes a pair of rotative driving members disposed at opposite end surfaces of the thermal transfer recording web roll, respectively, and capable of applying pressure to the end surfaces of the thermal transfer recording web roll.




According to the present invention, a thermal transfer recording web roll to be used for a thermal transfer printer, has a bore, and is formed for rolling a thermal transfer recording web; wherein a segment of the thermal transfer recording web forming the innermost layer of the thermal transfer recording web roll is fixed to a part of a segment of the thermal transfer recording web forming the second innermost layer of the thermal transfer recording web roll.




In the thermal transfer recording web roll according to the present invention, the segment of the innermost layer of the thermal transfer recording web roll excluding an inner edge part is fixed to the second innermost layer of the thermal transfer recording web roll.




According to the present invention, the thermal transfer recording web roll does not need any feed core, is inexpensive, can be prepared without requiring time and effort, and is capable of recording a thermal transfer image in a satisfactory image quality.




According to the present invention, the segment of the innermost layer of the thermal transfer recording web roll, excluding an inner end part, of the thermal transfer recording web roll is fixed to the part of the second innermost layer, and the rotative driving mechanism includes a pair of flanged tubular shafts each having a tubular part provided with a slit.




According to the present invention, the tubular part of one of the flanged tubular shaft is inserted into the tubular part of the other flanged tubular shaft.




According to the present invention, the pair of flanged tubular shafts are driven individually by separate driving mechanisms, respectively.




According to the present invention, one of the flanged tubular shafts is provided with a central rod connected to the other flanged shaft.




According to the present invention, the pair of flanged tubular shafts are supported for rotation by support members, respectively.




According to the present invention, the thermal transfer recording method uses a thermal transfer recording web roll in which the segment of the innermost layer of the thermal transfer web roll excluding an inner end part, is fixed to the part of the second innermost layer, and the thermal transfer web roll is driven for rotation by the rotative driving mechanism including a pair of flanged tubular shafts each having a tubular part provided with a slit.











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

is a schematic view of a thermal transfer printer in a first embodiment according to the present invention;




FIGS.


2


(


a


) and


2


(


b


) are end views of a thermal transfer recording web roll;





FIG. 3

is a schematic plan view of a holding device for holding an inner end part of a thermal transfer recording web;




FIGS.


4


(


a


),


4


(


b


) and


4


(


c


) are views of a holding device for holding an inner end segment of a thermal transfer recording web rolled in a thermal transfer recording web roll in a preferred embodiment according to the present invention;




FIGS.


5


(


a


),


5


(


b


) and


5


(


c


) are views of a thermal transfer recording web roll in a preferred embodiment according to the present invention;




FIGS.


6


(


a


),


6


(


b


) and


6


(


c


) are views of a thermal transfer recording web roll in a preferred embodiment according to the present invention;




FIGS.


7


(


a


),


7


(


b


) and


7


(


c


) are views of a thermal transfer recording web roll in a preferred embodiment according to the present invention;





FIG. 8

is schematic end view of a holding device for holding an inner end part of a thermal transfer recording web rolled in a thermal transfer recording web roll according to the present invention;





FIG. 9

is a side elevation of assistance in explaining an operation for loading a thermal transfer recording web roll into a recording web feed unit included in the thermal transfer printer of the present invention;





FIG. 10

is a schematic view of a thermal transfer printer in a second embodiment according to the present invention;




FIGS.


11


(


a


) and


11


(


b


) are schematic sectional views of assistance in explaining an operation for putting a cap on a thermal transfer recording web roll according to the present invention;




FIGS.


12


(


a


) and


12


(


b


) are schematic sectional views of assistance in explaining an operation for putting a cap and a hollow member on a thermal transfer recording web roll according to the present invention;




FIGS.


13


(


a


) and


13


(


b


) are a schematic exploded perspective view and a perspective view, respectively, of assistance in explaining an operation for putting caps on a thermal transfer recording web roll according to the present invention;




FIGS.


14


(


a


) and


14


(


b


) are schematic end views of thermal transfer recording web rolls according to the present invention;





FIG. 15

is a schematic exploded perspective view of assistance in explaining a cap capable of firmly connected to a recording web roll;





FIG. 16

is a schematic view of a thermal transfer printer in a third embodiment according to the present invention;





FIG. 17

is an end view of a thermal transfer recording web roll according to the present invention;




FIGS.


18


(


a


) and


18


(


b


) are schematic views of an essential part of the thermal transfer printer shown in

FIG. 16

;





FIG. 19

is a schematic end view of a thermal transfer recording web roll according to the present invention;





FIG. 20

is a schematic sectional view of a part of a thermal transfer printer according to the present invention;





FIG. 21

is a schematic view of a thermal transfer printer in a fourth embodiment according to the present invention;





FIG. 22

is a schematic sectional view of a part of the thermal transfer printer shown in

FIG. 21

;





FIG. 23

is a schematic end view of a thermal transfer recording web roll according to the present invention;




FIGS.


24


(


a


) and


24


(


b


) are schematic sectional views of a rotative driving device for holding a thermal transfer recording web roll by the opposite ends thereof;




FIGS.


25


(


a


) and


25


(


b


) are schematic sectional views of a rotative driving device including a center shaft of a variable length;





FIG. 26

is a schematic view of a thermal transfer printer in a fifth embodiment according to the present invention;




FIGS.


27


(


a


) and


27


(


b


) are schematic perspective views of assistance in explaining a procedure for fitting flanged tubular shafts on a thermal transfer recording web roll;




FIGS.


28


(


a


) to


28


(


f


) are end views of assistance in explaining a process in which a segment of a thermal transfer recording web forming the inner most layer of a thermal transfer recording web roll employed in the present invention is caught by a flanged shaft;





FIG. 29

is a schematic view of assistance in explaining a state in which a segment of a thermal transfer recording web forming the innermost layer of a thermal transfer recording web roll employed in the present invention is caught between flanged tubular shafts;





FIG. 30

is a schematic view of a thermal transfer recording web roll according to the present invention loaded into a thermal transfer printer;




FIGS.


31


(


a


) to


31


(


c


) are perspective views of assistance in explaining a method of fitting a flanged tubular shaft provided with a central rod on a thermal transfer recording web roll;




FIGS.


32


(


a


) to


32


(


d


) are schematic end views of assistance in explaining a method of forming a thermal transfer recording web roll according to the present invention;




FIGS.


33


(


a


) to


33


(


d


) are views of assistance in explaining a method of forming a thermal transfer recording web roll according to the present invention; and




FIGS.


34


(


a


) and


34


(


b


) are perspective views assistance in explaining a means for preventing flanged shafts from rattling relative to each other.











DESCRIPTION OF THE PREFERRED EMBODIMENTS




First Embodiment




A thermal transfer printer in a first embodiment according to the present invention will be described with reference to

FIGS. 1

to


9


.




Referring to

FIG. 1

, a thermal transfer printer


1


has a thermal transfer recording web roll


2


, a recording web feed unit


3


holding the thermal transfer recording web roll


2


therein, a thermal transfer recording unit


5


for recording images by a thermal transfer recording method on a thermal transfer recording web


2




a


unwound from the thermal transfer recording web roll


2


, and a cutting unit


9


for cutting the thermal transfer recording web


2




a


into sheets.




As shown in FIG.


2


(


a


), the thermal transfer recording web roll


2


is formed by rolling the thermal transfer recording web


2




a


. Apart


7


of the inner most layer


6


of the thermal transfer recording web roll


2


is bonded to the second innermost layer


7




a


of the thermal transfer recording web roll


2


, leaving an inner end segment


6




a


in a free state. The recording web feed unit


3


is provided with a holding device (rotative driving mechanism)


4


. The holding device


4


is inserted in the bore


8


of the thermal transfer recording web roll


2


. The diameter of the holding device


4


is approximately equal to that of the bore


8


of the thermal transfer recording web roll


2


.




The thermal transfer recording web


2




a


is pulled out from the recording web feed unit


3


by feed rollers


17


, i.e., an upper pinch roller and a lower grip roller, in the direction of the arrow such that the leading edge of a section of the thermal transfer recording web


2




a


is located at a print-starting position. Then, the feed rollers


17


are reversed and the thermal transfer recording web roll


2


is turned in a winding direction to move the thermal transfer recording web


2




a


for printing in a direction opposite to the direction of the arrow.




The thermal transfer recording web


2




a


is extended tautly between the holding device


4


and the feed rollers


17


. An operation for feeding and winding the thermal transfer recording web


2




a


is controlled mainly by rotating the feed rollers


17


in the normal or the reverse direction. The holding device


4


is interlocked with the feed rollers


17


so as to rotate the thermal transfer recording web roll


2


according to the rotation of the feed rollers


17


to unwind or wind the thermal transfer recording web


2




a


subordinately to the operation of the feed rollers


17


. Although it is preferable that the thermal transfer recording web roll


2


does not slip relative to the holding device


4


, the thermal transfer recording web roll


2


may slip in some degree relative to the holding device


4


, provided that the thermal transfer recording web


2




a


is not creased.




The thermal transfer recording unit


5


is provided with a thermal transfer sheet


16


and a thermal head


14


. The thermal head


14


is brought into contact with the back surface of the thermal transfer sheet


16


. The thermal transfer recording web


2




a


is extended with its recording surface in contact with the surface coated with a transfer layer (the front surface) of the thermal transfer sheet


16


. A platen roller


15


is disposed opposite to the thermal head


14


so as to be in contact with the back surface of the thermal transfer recording web


2




a


. When printing an image by thermal transfer recording on the thermal transfer recording web


2




a


, the thermal head


14


is lowered in the direction of the arrow to transfer a color image from the thermal transfer sheet


16


to the thermal transfer recording web


2




a.






Preferably, two guide members, not shown, are extended along the opposite side edges of the thermal transfer recording web


2




a


, respectively, between the recording web feed unit


3


and the thermal transfer recording unit


5


to prevent the thermal transfer recording web


2




a


from meandering.




Desirably, the distance between the two guide members is adjustable according to the width of the thermal transfer recording web


2




a


. For example, pins and dice which engage with each other are attached to parts of the thermal transfer printer


1


to which the guide members are attached, the plurality of dice are attached to a member, and the member provided with the dice and a member provided with the pins are slid relative to each other. The pins are fitted in the dice located at positions corresponding to the width of the thermal transfer recording web


2




a


. Thus, the thermal transfer recording web


2




a


slides along the guide members, the guide members restrain the thermal transfer recording web


2




a


from lateral movement and hence the thermal transfer recording web


2




a


is prevented from meandering.




The cutting unit


9


of the thermal transfer printer


1


cuts the thermal transfer recording web


2




a


into sheets. The printed thermal transfer recording web


2




a


may be taken up in a printed thermal transfer recording web roll.




FIGS.


2


(


a


) and


2


(


b


) are views of assistance in explaining a thermal transfer recording web roll according to the present invention. As shown in FIG.


2


(


a


), a thermal transfer recording web


2




a


is rolled in a thermal transfer recording web roll


2


. Apart


7


of the inner most layer


6


at a predetermined distance from the inner edge of the thermal transfer recording web


2




a


of the thermal transfer recording web roll


2


is bonded to the second innermost layer of the thermal transfer recording web roll


2


, leaving a free inner end segment


6




a


. The part


7


may be bonded to the second innermost layer of the thermal transfer recording web roll


2


with a single-coated adhesive tape, a double-coated adhesive tape, a liquid or solid adhesive or with a staple. The thermal transfer recording web roll


2


is a coreless roll having a central bore


8


.




The inner end segment


6




a


of the thermal transfer recording web roll


2


shown in FIG.


2


(


a


) is clamped by the holding device


4


of the thermal transfer printer


1


as shown in FIG.


2


(


b


). The holding device A is inserted in the bore


8


of the thermal transfer recording web roll


2


, and the inner end segment


6




a


of the innermost layer


6


is fixedly clamped by the holding device


4


. The holding device


4


of the thermal transfer printer


1


is provided with a recess


19


extending along the inner circumference of the bore


8


of the thermal transfer recording web roll


2


. The inner end segment


6




a


of the innermost layer


6


of the thermal transfer recording web roll


2


is placed in the recess


19


. A pressing member


20


is placed opposite to the recess


19


to press the inner end segment


6




a


of the innermost layer


6


of the thermal transfer recording web roll


2


against the bottom surface of the recess


19


to fasten the inner end segment


6




a


to the holding device


4


.




An opening


21


is formed in the inner end segment


6




a


of the innermost layer


6


. A projection


22


formed in a front part of the recess


19


is engaged in the opening


21


. The projection


22


is engaged in the opening


21


of the inner end segment


6




a


of the innermost layer


6


, the inner end segment


6




a


is fastened to the recess


19


of the holding device


4


, and then the thermal transfer recording web


2




a


is wound in the direction of the arrow shown in FIG.


2


(


b


). Since the projection


22


is engaged in the opening


21


of the thermal transfer recording web


2




a


, the thermal transfer recording web roll


2


does not slip relative to the holding device


4


, and the separation of the inner end segment


6




a


of the innermost layer


6


of the thermal transfer recording web


2




a


from the holding device


4


can be prevented.




When the thermal transfer recording web roll


2


needs to be replaced with another one before the thermal transfer recording web


2




a


of the same is exhausted, the thermal transfer recording web roll


2


may be removed from the holding device


4


of the thermal transfer printer


1


by sliding the thermal transfer recording web roll


2


relative to the holding device


4


.




The holding device


4


has the shape of a shaft and is provided with the recess


19


(groove). The inner end segment


6




a


of the innermost layer


6


placed in the recess


19


is held fixedly in place by the pressing member


20


to fasten the holding device


4


to the thermal transfer, recording web roll


2


. A holding device provided with a groove for holding the innermost layer


6


in its inner part may be used; part of the innermost layer


6


is inserted in the groove and the thermal transfer recording web roll


2


and the holding device can be fastened together without using any pressing member.





FIG. 3

shows such a holding device


4


including a shaft


11


provided with a groove


10


. The inner end segment


6




a


of the innermost layer


6


of the thermal transfer recording web


2




a


is inserted through an opening


23


formed in the circumference of the holding device


4


in the groove


10


. An opening


21


is formed in a part of the innermost layer


6


, at a short distance from the inner edge


18


of the inner most layer


6


, and a projection


22


formed in the bottom of the groove


10


is engaged in the opening


21


to hold the innermost layer


6


on the holding device


4


. The innermost layer


6


of the thermal transfer recording web


2




a


is fixed to the holding device


4


, rotative driving force of the thermal transfer printer


1


is transmitted to the holding device


4


during the thermal transfer printing operation, the holding device


4


and the thermal transfer recording web roll


2


rotate together during the thermal transfer printing operation, and the innermost layer


6


of the thermal transfer recording web


2




a


does not come off the holding device


4


.




In order that apart


24


of the thermal transfer recording web


2




a


extending around the opening


23


can extend close to the circumference of the shaft


11


of the holding device in a state where the holding device


4


shown in FIG.


3


and the thermal transfer recording web roll


2


are fastened together, it is preferable that the part


24


is perforated or pressed to make the part


24


flexible.




FIGS.


4


(


a


),


4


(


b


) and


4


(


c


) are views of a holding device for holding an inner end segment of a thermal transfer recording web. As shown in FIG.


4


(


a


), perforated lines


25




a


and


25




b


are formed symmetrically and through holes


26




a


and


26




b


are formed symmetrically in an inner end segment


6




a


of the innermost layer


6


of a thermal transfer recording web


2


. Triangular corner parts of the inner end segment


6




a


are bent in the same direction such that sides B and D are joined and corners E and F are joined. Thus, a triangle having sides A, B and


25




a


(perforated line) and a triangle having sides C, D and


25




b


(perforated line) are formed in the bore


8


of the thermal transfer recording web roll


2


. The through holes


26




a


and


26




b


are at the centers of those triangles, respectively. A part of the innermost layer


6


of the thermal transfer recording web roll


2


is bonded to the second innermost layer of the thermal transfer recording web roll


2


. A perforated line


25




c


is formed in the innermost layer


6


as shown in FIG.


4


(


a


) so that the triangles are positioned in the bore


8


with their centers coincided with the axis of the bore


8


.




The through holes


25




a


and


25




b


are axially aligned in the bore


8


of the thermal transfer recording web roll


2


in a state shown in FIG.


4


(


b


), and a shaft


11




a


included in the holding device


4


is passed through the through holes


25




a


and


25




b


as shown in FIG.


4


(


c


).




The inner end segment


6




a


of the innermost layer


6


is inserted in a space between the shaft


11




a


and a shaft


11




b


inserted in the bore


8


as shown in FIG.


4


(


c


). The shafts


11




a


and


11




b


and the thermal transfer recording web roll


2


rotate together. Base end parts of the shafts


11




a


and


11




b


are connected and are rotated through gears or the like by the rotative driving force of the thermal transfer printer


1


. Thus, the shafts


11




a


and


11




b


move in a body and serve as drive shafts.




FIGS.


5


(


a


),


5


(


b


) and


5


(


c


) are views of a thermal transfer recording web roll


2


according to the present invention. As shown in FIG.


5


(


a


), a perforated line


25


is formed in a part of an inner end segment


6




a


of the innermost layer


6


of the thermal transfer recording web roll


2


at a distance from the inner edge


18


of the inner end segment


6




a


. The inner end segment


6




a


is bent along the perforated line


25


. As shown in FIG.


5


(


b


), a part


7


of the innermost layer


6


is bonded to the second innermost layer of the thermal transfer recording web roll


2


with a single-coated adhesive tape, a double-coated adhesive tape, a liquid or solid adhesive or with a staple. Thus, the thermal transfer recording web roll


2


is a coreless roll having a central bore


8


.




The inner end segment


6




a


of the innermost layer


6


of the thermal transfer recording web


2




a


is bent in a closed curve in the bore


8


, and the inner edge


18


is bonded to the thermal transfer recording web


2




a


as shown in FIG.


5


(


b


).




When loading the thermal transfer recording web roll


2


into the recording web feed unit


3


of the thermal transfer printer


1


, shafts


11




a


and


11




b


included in the holding device


4


of the thermal transfer printer


1


are inserted in the bore


8


so as to lie near the inner end edge


18


. The shafts


11




a


and


11




b


roll along the side surface of the bore


8


toward each other to hold the innermost layer


6


between them. The shafts


11




a


and


11




b


turn together with the thermal transfer recording web roll


2


. Base end parts of the shafts


11




a


and


11




b


are connected and are driven for turning through gears or the like by the rotative driving force of the thermal transfer printer


1


for turning in a body.




FIGS.


6


(


a


),


6


(


b


) and


6


(


c


) are views of a thermal transfer recording web roll


2


according to the present invention. As shown in FIG.


6


(


a


), a perforated line


25


is formed in a part of an inner end segment


6




a


of the innermost layer


6


of the thermal transfer recording web roll


2


at a distance from the inner edge


18


of the inner end segment


6




a


. The inner end segment


6




a


is bent along the perforated line


25


. As shown in FIG.


6


(


b


), a part


7


of the innermost layer


6


is bonded to the second innermost layer of the thermal transfer recording web roll


2


.




The inner end segment


6




a


of the innermost layer


6


of the thermal transfer recording web


2




a


is bent in a closed curve in the bore


8


, and the inner edge


18


is bonded to the thermal transfer recording web


2




a


as shown in FIG.


6


(


b


).




When loading the thermal transfer recording web roll


2


into the recording web feed unit


3


of the thermal transfer printer


1


, shafts


11




a


and


11




b


included in the holding device


4


of the thermal transfer printer


1


are inserted in the bore


8


so as to lie near the inner end edge


18


as shown in FIG.


6


(


c


). The shafts


11




a


and


11




b


roll along the side surface of the bore


8


toward each other to hold the innermost layer


6


between them. The shafts


11




a


and


11




b


turn together with the thermal transfer recording web roll


2


. Base end parts of the shafts


11




a


and


11




b


are connected and are driven for turning through gears or the like by the rotative driving force of the thermal transfer printer


1


for turning in a body.




The closed curve in which the inner end segment


6




a


of the thermal transfer recording web


2




a


of the thermal transfer recording web roll


2


shown in

FIG. 6

is different from that in which the inner end segment


6




a


of the thermal transfer recording web


2




a


of the thermal transfer recording web roll


2


shown in FIG.


5


. FIGS.


7


(


a


),


7


(


b


) and


7


(


c


) are views of a thermal transfer recording web roll


2


according to the present invention. As shown in FIG.


7


(


a


), three perforated lines


25




a


,


25




b


and


25




c


are formed in parts of an inner end segment


6




a


of the innermost layer


6


of the thermal transfer recording web roll


2


at distances from the inner edge


18


of the inner end segment


6




a


. The inner end segment


6




a


is bent along the perforated lines


25




a


and


25




b


such that the end edge


18


touches a part of the inner end segment


6




a


between the perforated lines


25




b


and


25




c


to form a triangle in the bore


8


of the thermal transfer recording web roll


2


as shown in FIG.


7


(


b


) The end edge


18


at one of the vertices of the triangle is bonded to the side surface of the bore


8


by the aforesaid means.




The inner end segment


6




a


of the innermost layer


6


of the thermal transfer recording web


2




a


is bent along the perforated line


25




c


and a part


7


of the inner end segment


6




a


is bonded to the second innermost layer of the thermal transfer recording web roll


2


as shown in FIG.


7


(


b


) by the aforesaid bonding means. The thermal transfer recording web roll


2


is a coreless roll having a central bore


8


.




When loading the thermal transfer recording web roll


2


into the recording web feed unit


3


of the thermal transfer printer


1


, shafts


11




a


and


11




b


included in the holding device


4


of the thermal transfer printer


1


are inserted in the bore


8


so as to lie near the inner end edge


18


; The shafts


11




a


and


11




b


roll along the side surface of the bore


8


toward each other to hold the innermost layer


6


between them. The shafts


11




a


and


11




b


turn together with the thermal transfer recording web roll


2


. Base end parts of the shafts


11




a


and


11




b


are connected and are driven for turning through gears or the like by the rotative driving force of the thermal transfer printer


1


for turning in a body.




Although the inner end segments


6




a


of the thermal transfer recording web rolls


2


shown in

FIGS. 5

,


6


and


7


are bent in the closed curves and the triangle, respectively, in the bore


8


, the inner end segments


6




a


may be bent in any optional shape, such as any closed curve or any polygon. The holding device


4


is not limited to those shown in

FIGS. 5

,


6


and


7


each including the two shafts


11




a


and


11




b


, but may be any suitable device. For example, the holding device


4


may include a shaft


13


of a diameter equal to that of the bore


8


of the thermal transfer recording web roll


2


as shown in FIG.


8


. The shaft


13


is provided with a cavity


12


conforming to the inner end segment


6




a


shaped in the closed curve or the polygon in the bore


8


, a groove


27


having an open end


7




a


and connected to the cavity


12


. The shaft


13


has a cylindrical shape coinciding with the bore


8


of the thermal transfer recording web roll


2


.





FIG. 9

is a side elevation of assistance in explaining an operation for loading a thermal transfer recording web roll


2


into a recording web feed unit


3


of the thermal transfer printer


1


of the present invention. A shaft


13


included in a holding device


4


is inserted in the bore


8


of the coreless thermal transfer recording web roll


2


. The thermal transfer recording web roll


2


is fastened to a holding device


4


of a shape conforming to the shape of the bent inner end segment


6




a


of the thermal transfer recording web


2




a


of the thermal transfer recording web roll


2


. A flange


30


is attached to one end of the shaft


13


to be inserted in the bore


8


of the thermal transfer recording web roll


2


. The thermal transfer recording web roll


2


can be easily located on the shaft


13


by putting one end


31


of the thermal transfer recording web roll


2


to the flange


30


. The other end


33


of the shaft


13


is fitted in a flange


29


integrally provided with a gear


28


. The other end


32


of the thermal transfer recording web roll


2


comes into contact with the flange


29


, so that the thermal transfer recording web roll


2


is held between the flanges


29


and


30


and is protected from abrasion when the same is rotated. The shaft


13


may be fitted in the flange


29


by any method, provided that the method is able to fit the shaft


13


in the flange


29


by axially moving the shaft


13


, i.e., laterally moving the shaft


13


as viewed in

FIG. 9

, and to prevent the shaft


13


from coming off the flange


29


when the gear


28


and the thermal transfer recording web roll


2


are rotated. The flange


29


and the shaft


13


may be provided with pins and dice capable of engaging with the pins, respectively. The thermal transfer recording web roll


2


is thus fixed to the holding device


4


, the holding device


4


holding the thermal transfer recording web roll


2


is loaded into the recording web feed unit


3


of the thermal transfer printer


1


. During the thermal transfer recording operation, rotative driving force of the thermal transfer printer


1


is transmitted to the gear


28


to rotate the holding device


4


combined with the gear


28


and the thermal transfer recording web roll


2


.




The length of the shaft


13


of the holding device


4


employed in the present invention may be adjustable according to the width of the thermal transfer recording web roll


2


. A thermal transfer recording web


2




a


having the same width as sheets of a standard trim size, such a standard trim size A3, B3, A4, B4, A5 or B5, is used and the thermal transfer recording web


2




a


is cut into sheets of the same length as sheets of the standard trim size when the thermal transfer recording web


2


is to be cut after being printed into sheets of the standard trim size. Suppose that the thermal transfer recording web


2




a


is to be cut into sheets of the standard trim size A4 after printing, a thermal transfer recording web roll


2


having an axial length equal to the width of the sheet of the standard trim size A4 is used and the thermal transfer recording web


2




a


unwound from the thermal transfer recording web roll


2


is cut into sheets of the same length as the sheets of the standard trim size A4 by the cutting unit


9


.




When the length of the shaft


13


needs to be adjustable, the shaft


13


is formed by combining a first member provided with dice, and a second member provided with pins so as to be axially slidable relative to each other. The pins of the second member is fitted in dices of the first member, corresponding to the width of the thermal transfer recording web


2




a.






According to the present invention, it is important that the holding device


4


holding the inner end segment


6




a


of the thermal transfer recording web


2




a


does not slip relative to the thermal transfer recording web roll


2


or the slip of the holding device


4


relative to the thermal transfer recording web roll


2


does not affect the quality of printed images. Preferably, the thermal transfer recording web


2




a


employed in the present invention has a base web, and a dye-recipient layer formed on the base web and capable of receiving dyes from the color transfer layer of a thermal transfer sheet.




The base web of the thermal transfer recording web


2




a


maybe a paper web, a synthetic paper sheet or a plastic sheet. The dye-recipient layer may be formed directly on the base web or on a primer layer formed on the base web. However, it is preferable to provide the thermal transfer recording web


2




a


with a high print sensitivity and to form a layer having minute voids on the base web to print images of a high image quality not having density irregularity and voids. The layer having minute voids may be a plastic sheet or a synthetic paper sheet.




Layers having minute voids can be formed on various base sheets by various coating methods. A desirable plastic or synthetic paper sheet having minute voids can be formed by preparing a mixture of a polyolefin resin, more specifically, a polypropylene resin, inorganic pigment and/or a polymer incompatible with the polypropylene resin, and a void-formation initiator, spreading the mixture in a film and drawing the film.




The plastic or synthetic paper sheet may be a single layer sheet having minute voids or a multiplayer sheet having minute voids. The multiplayer sheet may have minute voids in all the component layers thereof or may include some component layers not having minute voids. The plastic or synthetic paper sheet may contain a white pigment as a covering agent when necessary. Additives including an optical whitening agent may be added to the plastic or synthetic paper sheet to enhance the whiteness of the plastic or synthetic paper sheet.




The base sheet may be coated with a layer having minute voids by a coating method. Possible plastic resins are polyester resins, urethane resins, polycarbonate resins, acrylic resins, polyvinyl chloride resins, polyvinyl acetate resins or mixtures of some of those resins. The base sheet may be a generally know base sheet. Possible base sheets include paper sheets, such as wood-free paper sheets, coat paper sheets, art paper sheets, cast-coated paper sheets and glassine paper sheet, synthetic paper sheets, nonwoven fabric sheets, and plastic sheets, such as polyethylene terephthalate resin sheets, acrylic resin sheets, polyethylene resin sheets and polypropylene resin sheets.




The base sheet may be a paper sheet, a synthetic paper sheet or a plastic sheet and it is preferable to coat the base sheet with a layer having minute voids. A plastic sheet or a synthetic paper sheet serving as a layer having minute voids may be bonded to the base sheet with an adhesive layer by a known lamination process, such as a dry lamination process, a hot-melt lamination process or an EC lamination process.




The holding device


4


for clamping the inner end segment of the thermal transfer recording web


2




a


of the thermal transfer recording web


2


of the thermal transfer printer


1


of the present invention may be formed of a durable metal, such as aluminum, iron or a stainless steel, or may be formed of a resin, such as a polystyrene resin, vinyl chloride resin, a polycarbonate resin or a polyester resin, by an injection molding process. Preferably, the surface of a part of the holding device


4


to be brought into direct contact with the innermost layer


6


is provided with small ridges or small knobs formed in an optional pattern by a diamond-cutting process, a satin-finishing process or an embossing process. It is preferable to determine embossing depth, i.e., the height of projections of the irregularities, such that the holding device is able to exert a frictional resistance sufficient to prevent the innermost layer


6


from slipping relative to the holding device on the innermost layer


6


. For example, the embossing depth is in the range of about 5 to about 500 μm.




A thermal transfer recording method according to the present invention does not use any core. The part


7


at a distance from the inner end edge


18


of the thermal transfer recording web


2




a


of the innermost layer


6


of the thermal transfer recording web roll


2


is bonded to the second innermost layer of the thermal transfer recording web roll


2


, leaving the inner end segment


6




a


in a free state. The holding device


4


is inserted in the bore


8


of the thermal transfer recording web roll


2


, the innermost layer


6


is clamped by the holding device


4


, the holding device


4


of the thermal transfer printer


1


and the thermal transfer recording web roll


2


are rotated in a body for thermal transfer printing. The rotation of the feed rollers


17


is controlled to feed the thermal transfer recording web


2




a


, and the holding device


4


rotates the thermal transfer recording web roll


2


according to the rotation of the feed rollers


17


to assist the operation for feeding the thermal transfer recording web


2




a


. Therefore, it is preferable that the thermal transfer recording web roll


2


does not slip relative to the holding device


4


. However, the thermal transfer recording web roll


2


may slip in some degree relative to the holding device


4


, provided that the thermal transfer recording web


2




a


is neither creased nor folded.




When printing a full-color image by a thermal transfer printing operation using three colors, i.e., yellow, magenta and cyan, a yellow dye is transferred from a yellow transfer layer of a thermal transfer sheet


16


to the entire printing area of the thermal transfer recording web


2




a


in a yellow image by heating the yellow transfer layer of the thermal transfer sheet


16


with the thermal head


14


, in which the thermal transfer sheet


16


and the thermal transfer recording web


2




a


are moved together in a forward direction (or a backward direction) by a distance corresponding to the length of the print. Then, the leading edge of a magenta layer of the thermal transfer sheet


16


is located under the thermal head


14


, and the thermal transfer recording web


2




a


is reversed so that the leading edge of the printing area is located under the thermal head


14


.




Then, a magenta dye is transferred from a magenta transfer layer of the thermal transfer sheet


16


to the entire printing area of the thermal transfer recording web


2




a


in a magenta image by heating the magenta transfer layer of the thermal transfer sheet


16


with the thermal head


14


. Similarly, a cyan dye is transferred from a cyan transfer layer of the thermal transfer sheet


16


to the entire printing area of the thermal transfer recording web


2




a


in a cyan image by heating the cyan transfer layer of the thermal transfer sheet


16


with the thermal head


14


to complete a full-color printed image. Then, a printed section of the thermal transfer recording web


2




a


is moved in a delivery direction and, when necessary, the printed section is cut in a sheet.




The thermal transfer recording method according to the present invention reciprocates the thermal transfer recording web


2




a


under the thermal head


14


; that is the thermal transfer recording web roll


2


is turned in the normal direction and then in the reverse direction for one thermal transfer recording cycle. When images of different colors are superposed to print a full-color image, the image quality of the full-color image is deteriorated unless the images of different colors are registered accurately.




According to the present invention, the innermost layer


6


of the thermal transfer recording web roll


2


is hardly able to slip relative to the holding device


4


, and the rotation of the thermal transfer recording web roll


2


can be accurately controlled.




As apparent from the foregoing description, the thermal transfer printer according to the present invention uses the coreless thermal transfer recording web roll, and the innermost layer of the thermal transfer recording web roll excluding the inner end part is fixed to the second innermost layer of the thermal transfer recording web roll. The innermost layer of the thermal transfer recording web roll is held by the holding device, and the thermal transfer recording web roll rotates together with the holding device for thermal transfer printing. Thus, any core is not necessary for holding the thermal transfer recording web roll, the thermal transfer recording web roll can be prepared at a low cost without requiring much time and effort, and an image of an excellent image quality can be formed by thermal transfer printing.




Second Embodiment





FIGS. 10

to


15


are schematic views showing a thermal transfer printer


101


in a second embodiment according to the present invention. The thermal transfer printer


101


has a thermal transfer recording web roll


102


formed by rolling a thermal transfer recording web


102




a


, a recording web feed unit


103


for holding the thermal transfer recording web roll


102


and feeding the thermal transfer recording web


102




a


, two caps (rotative driving mechanisms)


110


for holding the thermal transfer recording web roll


102


in the recording web feed unit


103


, each provided with a flange


112


, a thermal transfer recording unit


105


capable of printing an image on the thermal transfer recording web


102




a


by a thermal transfer printing method, and a cutting unit


109


for cutting the thermal transfer recording web


102




a


into sheets.




The thermal transfer recording web


102




a


is pulled out from the recording web feed unit


103


by feed rollers


117


in the direction of the arrow, and the leading edge of a recording section of the thermal transfer recording web


102




a


is located at a print starting position. Then, an image is printed on the recording section of the thermal transfer recording web


102




a


, while the feed rollers


117


are reversed to move the thermal transfer recording web


102




a


in the reverse direction, i.e., a direction opposite to the direction of the arrow, and the recording section is taken up on the thermal transfer recording web roll


102


. The thermal transfer recording web


102




a


is extended tautly between the caps


110


and the feed rollers


117


. The movement of the thermal transfer recording web


102




a


is controlled principally by rotating the feed rollers


117


in the normal and the reverse direction. the caps


110


turn the thermal transfer recording web roll


102


according to the rotation of the feed rollers


117


to assist the operation for feeding the thermal transfer recording web


102




a


. Therefore, it is preferable that the thermal transfer recording web roll


102


does not slip relative to the caps


110


. However, the thermal transfer recording web roll


102


may slip in some degree relative to the caps


110


, provided that the thermal transfer recording web


102




a


is neither creased nor folded.




A thermal transfer sheet


116


is extended so that its back surface can be brought into contact with a thermal head


114


. The thermal transfer recording web


102




a


is extended with its recording surface in contact with the surface coated with a transfer layer (the front surface) of the thermal transfer sheet


116


. A platen roller


115


is disposed opposite to the thermal head


114


so as to be in contact with the back surface of the thermal transfer recording web


102




a


. When printing an image by thermal transfer recording on the thermal transfer recording web


102




a


, the thermal head


114


is lowered in the direction of the arrow to transfer a color image from the thermal transfer sheet


116


to the thermal transfer recording web


102




a.






Preferably, two guide members, not shown, are extended along the opposite side edges of the thermal transfer recording web


102




a


, respectively, between the recording web feed unit


103


and the thermal transfer recording unit


105


to prevent the thermal transfer recording web,


102




a


from meandering.




Desirably, the distance between the two guide members is adjustable according to the width of the thermal transfer recording web


102




a


. For example, pins and dice which engage with each other are attached to parts of the thermal transfer printer


101


to which the guide members are attached, the plurality of dice are attached to a member, and the member provided with the dice and a member provided with the pins are slid relative to each other. The pins are fitted in the dice located at positions corresponding to the width of the thermal transfer recording web


102




a


. Thus, the thermal transfer recording web


102




a


slides along the guide members, the guide members restrain the thermal transfer recording web


102




a


from lateral movement and hence the thermal transfer recording web


102




a


is prevented from meandering.




The cutting unit


109


of the thermal transfer printer


101


cuts the thermal transfer recording web


102




a


into sheets. The printed thermal transfer recording web


102




a


may be taken up in a printed thermal transfer recording web roll.




FIGS.


11


(


a


) and


11


(


b


) are sectional views of assistance in explaining a method of assembling the caps


110


and the thermal transfer recording web roll


102


. Referring to FIG.


11


(


a


) showing the cap


110


extracted from the bore


108


of the thermal transfer recording web roll


102


, the cap


110


has elastic tongues


111


formed by forming slits


118


in a cylindrical plug-shaped part to divide the cylindrical part into a plurality of tongues and bending the tongues so as to curve radially outward. The diameter c of an imaginary circle including the free ends of the elastic tongues


111


in a free state is greater than the diameter d of the bore


108


of the thermal transfer recording web roll


102


. The cap


110


has the elastic tongues


111


, a flange


112


and a gear


120


. The elastic tongues


111


are contracted radially in the directions of the arrows and are inserted in the bore


108


of the thermal transfer recording web roll


102


.




When putting the cap


110


on the thermal transfer recording web roll


102


, the elastic tongues


111


are contracted radially, the cap


110


is pushed in the direction of the blank arrow to insert the elastic tongues


111


in the bore


108


of the thermal transfer recording web roll


102


such that the inner. side surface of the flange


112


is pressed against one end surface


104


of the thermal transfer recording web roll


102


as shown in FIG.


11


(


b


).




A cap


110


similar to the cap


110


attached to the end


104


of the thermal transfer recording web roll


102


as shown in FIG.


11


(


b


) may be attached to the other end of the thermal transfer recording web roll


102


. The cap


110


to be attached to the other end of the thermal transfer recording web roll


102


may be such as having only elastic tongues


111


and a flange


112


and does not need to be provided with a gear.




The elastic tongues


111


are formed of an elastic material. Therefore, the resilience of the radially contracted elastic tongues


111


of the cap


110


causes the elastic tongues


111


to exert pressure on the side surface


113


of the bore


108


as shown in FIG.


11


(


b


). The material and the shape of the elastic tongues


111


are determined selectively such that proper friction is produced between the elastic tongues


111


and the thermal transfer recording web roll


102


, and the elastic tongues


111


are able to exert proper pressure on the thermal transfer recording web roll


102


so that the cap


110


attached to the thermal transfer recording web roll


102


may not easily come off the thermal transfer recording web roll


102


. Thus, the caps


110


and the thermal transfer recording web roll


102


rotate together for thermal transfer printing.




Although it is preferable that the thermal transfer recording web roll


2


may slip in some degree relative to the holding device


4


, provided that the thermal transfer recording web


2




a


is not creased. The thermal transfer web roll


102


does not slip relative to the caps


110


. The thermal transfer recording web roll


102


may slip in some degree relative to the caps


110


, provided that the slip of the thermal transfer recording web roll


102


relative to the caps


110


does not affect adversely to image quality.




FIGS.


12


(


a


) and


12


(


b


) are schematic sectional views of assistance in explaining work for assembling a thermal transfer recording web roll


102


of a thermal transfer recording web


102




a


, two caps


110




a


and


110




b


, and a bushing


123


provided with a slit


118


. In FIG.


12


(


a


), the bushing


123


provided with the slit


118


is fitted in the bore


108


of the thermal transfer recording web roll


102


, and the plug-shaped parts


111




a


and


111




b


of the two caps


110




a


and


110




b


are not yet fitted in the bushing


123


. The outside diameter of the bushing


123


in a free state is slightly greater than the diameter of the bore


108


of the thermal transfer recording web roll


102


. The bushing


123


is radially contracted narrowing the slit


118


and is inserted in the bore


108


of the thermal transfer recording web roll


102


. Desirably, an inner end segment


119


of the innermost layer


106


of the thermal transfer recording web


102




a


is inserted in the slit


118


of the bushing


123


as shown in

FIG. 15

to fix the thermal transfer recording web roll


102


to the bushing


123


firmly. Preferably, the inner end segment


119


is tapered toward its edge to prevent the inner end segment


119


from obstructing the engagement of the two caps


110




a


and


110




b


in the opposite ends of the bushing


123


.




The respective plug-shaped parts


111




a


and


111




b


of the caps


110




a


and


110




b


are not provided with any slits. The plug-shaped parts


111




a


and


111




b


are tapered toward their free ends such that the diameter g of the end surfaces thereof is smaller than the inside diameter e of the bushing


123


as fitted in the bore


108


of the thermal transfer recording web roll


102


to facilitate inserting the plug-shaped parts


111




a


and


111




b


of the caps


110




a


and


110




b


in the bushing


123


fitted in the bore


108


. The base parts of the plug-shaped parts


111




a


and


111




b


contiguous with the flanges


112




a


and


112




b


is formed in a diameter f slightly greater than the inside diameter


3


of the bushing


123


as fitted in the bore


108


of the thermal transfer recording web roll


102


to fit the plug-shaped parts


111




a


and


111




b


in the bushing


123


in a tight fit.




When the respective plug-shaped parts


111




a


and


111




b


of the caps


110




a


and


110




b


fitted in the bushing


123


fitted in the bore


108


of the thermal transfer recording web roll


102


, the plug-shaped parts


111




a


and


111




b


are pressed firmly against the inner circumference


124


of the bushing


123


. Consequently, the bushing


123


is expanded in the bore


108


, the width h of the slit


118


of the bushing


123


as fitted in the bore


108


is increased to a width i, and the bushing


123


is pressed firmly against the inner surface


113


of the bore


108


of the thermal transfer recording web roll


102


. The plug-shaped parts


111




a


and


111




b


of the caps


110




a


and


110




b


, when inserted in the bushing


123


fitted in the bore


108


, tend to expand the slit


118


. The bushing


123


is formed of an elastic material. Therefore, when the plug-shaped parts


111




a


and


111




b


of the caps


110




a


and


110




b


are extracted from the bushing


123


and the pressure applied to the bushing


123


is removed, the bushing


123


is contracted radially by its own resilience, and the slit


118


recovers its original width h. The caps


110




a


and


110




b


, particularly, the plug-shaped parts


111




a


and


111




b


are formed of a comparatively hard material in order that the dimensions of the same change scarcely when external force is exerted thereon.




FIGS.


13


(


a


) and


13


(


b


) are schematic sectional views of assistance in explaining work for assembling a thermal transfer recording web roll


102


of a thermal transfer recording web


102




a


according to the present invention, and caps


110




a


and


110




b


. FIG.


13


(


a


) shows the two caps


110




a


and


110




b


before being fitted in the bore


108


of the thermal transfer recording web roll


102


. The cap


110




a


has a flange


112




a


, and elastic tongues


111




a


spaced by slits


118


. The diameter j of a circle including the free ends of the elastic tongues


111




a


of the cap


110




a


may be either greater than or smaller than the diameter d of the bore


108


of the thermal transfer recording web roll


102


. The elastic tongues


111




a


can be radially contracted, so that the elastic tongues


111




a


can be easily inserted in the bore


108


of the thermal transfer recording web roll


102


.




The elastic tongues


111




a


of the cap


110




a


is inserted in the bore


108


as deep as the inner side surface of the flange


112




a


is pressed against an end surface


104


of the thermal transfer recording web roll


102


. The other cap


110




b


has a flange


112




b


and a plug-shaped part


125


. The plug-shaped part


125


of the cap


110




b


is inserted in the other end of the bore


108


of the thermal transfer recording web roll


102


as far as the plug-shaped part


125


is fitted in a space


126


surrounded by the elastic tongues


111




a


. Consequently, the elastic tongues


111




a


of the cap


110




a


are pressed radially outward and are pressed firmly against the side surface


113


of the bore


108


of the thermal transfer recording web roll


102


as shown in FIG.


13


(


b


).




Thus, the two caps


110




a


and


110




b


are combined in the bore


108


of the thermal transfer recording web roll


102


, the elastic tongues


111




a


of the cap


110




a


are pressed radially outward against the side surface


113


of the bore


108


by the plug-shaped part


125


of the other cap


110




b


. Consequently, the caps


110




a


and


110




b


and the thermal transfer recording web roll


102


are joined together in a body. Gears, not shown, of the thermal transfer printer


101


are engaged with gears, not shown, connected to the caps


110




a


and


110




b


drives the caps


110




a


and


110




b


for rotation together with the thermal transfer recording web roll


102


.




Preferably, the end surfaces of the elastic tongues


111




a


of the cap


110




a


are flat to facilitate the insertion of the plug-shaped part


125


of the other cap


110




b


in the space


126


surrounded by the elastic tongues


111




a


of the cap


110




a.






The elastic tongues


111




a


are formed of an elastic material and are capable of elastically bent radially inward by external force and of recovering its original shape when external force is removed from the elastic tongues


111




a


. The material and the shape of the elastic tongues


111




a


are determined selectively so that proper friction is produced between the elastic tongues


111




a


and the thermal transfer recording web roll


102


, and the elastic tongues


111




a


are able to exert proper pressure on the thermal transfer recording web roll


102


so that the caps


110




a


and


110




b


attached to the thermal transfer recording web roll


102


may not easily come off the thermal transfer recording web roll


102


. Thus, the caps


110




a


and


110




b


and the thermal transfer recording web roll


102


rotate together for thermal transfer printing.




FIGS.


14


(


a


) and


14


(


b


) are schematic end views of thermal transfer recording web rolls


102


according to the present invention. The thermal transfer recording web roll


102


shown in FIG.


14


(


a


) is formed by rolling a thermal transfer recording web in a coreless thermal transfer recording web roll


102


having a bore


108


, and bonding the innermost layer


106


to a part


107


of the second innermost layer


107




a


of the thermal transfer recording web roll


102


. Nothing projects from the inner surface


113


of the bore


108


into the bore


108


of the thermal transfer recording web roll


102


and the inner surface


113


of the bore


108


is cylindrical. The thermal transfer recording web roll


102


shown in FIG.


14


(


b


) is formed by rolling a thermal transfer recording web in a coreless roll, and bonding a part


107


of the innermost layer


106


at a distance from the inner end edge


127


of the thermal transfer recording web to the second innermost layer, leaving a free inner end segment


119


.




As shown in

FIG. 15

, the part


107


of the innermost layer


106


at a distance from the inner end edge


127


of the thermal transfer recording web is bonded to the second innermost layer, and the free inner end segment


119


extends from the part


107


. Thus, the free inner end segment


119


projects from the inner surface


113


of the bore


108


of the thermal transfer recording web roll


102


into the bore


108


. A cap


110


has an elastic plug-shaped part


111


provided with a slit


118


and a flange


112


. The elastic plug-shaped part


111


is fitted in the bore


108


of the thermal transfer recording web roll


102


so that the free inner end segment


119


is inserted in the slit


118


of the plug-shaped part


111


. The elastic plug-shaped part


111


is tapered as shown in

FIG. 12

or is formed in a shape resembling the plug-shaped part


125


of the cap


110




b


shown in FIG.


13


(


a


) to fit the plug-shaped part


111


in the bore


108


in close contact with the inner surface


113


of the bore


108


of the thermal transfer recording web roll


102


. The flange


112


of the cap


110


is in contact with an end surface of the thermal transfer recording web roll


102


to protect the end surface from abrasion when the thermal transfer recording roll


102


is rotated.




Referring to

FIG. 15

, when the plug-shaped part


111


of the cap


110


is fitted in the bore


108


of the thermal transfer recording web roll


102


, the inner end segment


119


extends between the inner end edge


127


of the thermal transfer recording sheet and the bonded part


107


. Preferably, the bonded part


107


is provided with a perforated line or a pressed line so that the inner end segment


119


can be bent along the bonded part


107


so as to extend radially.




According to the present invention, it is important that the elastic plug-shaped part


111


of the cap


110


or the bushing


123


is firmly engaged with the inner surface


113


of the bore


108


of the thermal transfer recording web roll


102


so that the elastic plug-shaped part


111


or the bushing


123


does not slip relative to the thermal transfer recording web roll


102


, or slips of the thermal transfer recording web roll


102


relative to the elastic plug-shaped part


111


or the bushing


123


does not affect adversely to image quality. Preferably, the thermal transfer recording web


102




a


employed in the present invention has a base web, and a conventional dye-recipient layer formed on the base web and capable of receiving dyes from the color transfer layer of a thermal transfer sheet.




The cap


110


, particularly, the plug-shaped part


111


of the cap


110


and the bushing


123


are formed of an elastic material. The plug-shaped part


111


and the bushing


123


can be elastically contracted when fitting the same in the bore


108


of the thermal transfer recording web roll


102


and are capable of recovering their original shapes, i.e., shapes in a free state. For example, the plug-shaped part


111


of the cap


110


, and the bushing


123


can be formed by molding a resin for injection molding, such as an elastic material, such as a polystyrene resin, a vinyl chloride resin, a polycarbonate resin or a polyester resin. When the cap


110


and the bushing


123


are used in combination, it is preferable that the material of the bushing


123


is harder than that of the cap


110


, the bushing


123


is more difficult to deform than the cap


110


, and the outside diameter of the bushing


123


is increased when the plug-shaped part


111


of the cap


110


is fitted in the bushing


123


.




When the caps


110




a


and


110




b


are fixedly held in the bore


108


of the thermal transfer recording web roll


102


and a part of the cap


110




b


is inserted into the. other cap


110




a


in the bore


108


, it is desirable that the cap


110




a


is formed of a material softer than that of the cap


110




b


and capable of being easily deformable so that the elastic tongues


111




a


of the cap


110




a


can be firmly pressed against the inner surface


113


of the bore


108


of the thermal transfer recording web roll


102


.




The thermal transfer recording method of the present invention employs the coreless thermal transfer recording roll


102


formed by rolling the thermal transfer recoding web


102




a


and having the innermost layer


106


bonded to the second innermost layer of the thermal transfer recording web roll


102


, and the two caps


110


are fitted in the bore


108


of the thermal transfer recording web roll


102


. At least one of the caps


110


is provided with the gear


120


, the gear


120


is driven to rotate the cap


110


together with the thermal transfer recording web roll


102


.




Preferably, at least one of the caps


110


is provided with the flange


112


to be brought into contact with an end surface of the thermal transfer recording web roll


102


.




The elastic tongues


111




a


of the cap


110




a


may be pressed against the inner surface


113


of the bore


108


of the thermal transfer recording web roll


102


by pressing the plug-shaped part


125


of the cap


110




b


into the space


126


surrounded by the elastic tongues


111




a


of the other cap


110




a


in the bore


108


.




The bushing


123


may be inserted in the bore


108


of the thermal transfer recording web roll


102


, and the plug-shaped parts


111




a


and


111




b


of the two caps


110




a


and


110




b


may be fitted in the opposite ends of the bushing


123


, respectively, to press the bushing


123


against the side surface


113


of the bore


108


of the thermal transfer recording web roll


102


.




The elastic tongue


111


of the cap


110


and/or the bushing


123


may be provided with a slit, and the inner end segment


119


of the thermal transfer recording web


102




a


of the thermal transfer recording web roll


102


may be inserted in the slit to combine the cap


110


and/or the bushing


123


firmly with the thermal transfer recording web; roll


102


.




In this thermal transfer recording method, the cap


110


, when necessary, the cap


110


and the bushing


123


are driven, for rotation to feed the thermal transfer recording web


102




a


. The cap


110


rotates the thermal transfer recording web roll


102


in synchronism with the rotation of the feed rollers


117


to assist feeding the thermal transfer recording web


102




a


. Although it is therefore preferable that the thermal transfer recording web roll


102


does not slip relative to the cap


110


, the thermal transfer recording web roll


102


may slip in some degree relative to the cap


110


, provided that the thermal transfer recording web


102




a


is neither creased nor folded.




According to the present invention, the rotation of the thermal transfer recording web roll


102


can be properly controlled by fitting the two caps


110


each having the elastic tongues


111


capable of applying pressure to the inner surface


113


of the bore


108


of the thermal transfer recording web roll


102


, and the flange


112


in contact with the end surface of the thermal transfer recording web roll


102


in the opposite ends of the thermal transfer recording web roll


102


, respectively.




As apparent form the foregoing description, the thermal transfer printer according to the present invention uses the coreless thermal transfer recording web roll in which the innermost layer is bonded to the second innermost layer. The elastic tongues of the two caps are fitted in the bore of the thermal transfer recording web roll. At least one of the caps is provided with the gear, the gear is driven to rotate the cap and the thermal transfer recording web roll together for thermal transfer printing.




The cap provided with the elastic tongues is inserted in one end of the thermal transfer recording web roll, the plug-shaped part of the other cap is inserted in the other end of the bore of the thermal transfer recording web roll as far as the plug-shaped part is fitted in the space surrounded by the elastic tongues to press the elastic tongues of the cap firmly against the inner surface of the bore of the thermal transfer recording web roll. The bushing is inserted in the bore of the thermal transfer recording web roll, and the plug-shaped parts of the two caps are pressed in the opposite ends of the bushing, respectively, to press the bushing firmly against the inner surface of the bore of the thermal transfer recording web roll.




Thus, the thermal transfer recording method of the present invention does not need any core for supporting the thermal transfer recording web roll, the thermal transfer recording web roll can be prepared at a low cost without requiring much time and effort, and images can be recorded on the thermal transfer recording web in a satisfactory image quality.




Third Embodiment




A third embodiment of the present invention will be described with reference to

FIGS. 16

to


20


.




Referring to

FIG. 16

, a thermal transfer printer


201


has a thermal transfer recording web roll


202


formed by rolling a thermal transfer recording web


202




a


, a recording web feed unit


203


holding the thermal transfer recording web roll


202


therein, a plurality of drive rollers (rotative driving mechanism)


210


and


211


inserted in the bore


208


of the thermal transfer recording web roll


202


, a thermal transfer recording unit


205


, and a cutting unit


209


for cutting the thermal transfer recording web


202




a


into sheets.




The drive rollers


210


and


211


are pressed against the inner surface


213


of the bore


208


of the thermal transfer recording web roll


202


. At least the drive roller


210


is driven to rotate the thermal transfer recording web roll


202


. The thermal transfer recording unit


205


records images on the thermal transfer recording web


202




a


, and the cutting unit


209


cuts the printed thermal transfer recording web


202




a


into sheets. The thermal transfer recording web


202




a


is pulled out in the direction of the arrow from the thermal transfer recording web roll


202


held in the recording web feed unit


203


by feed rollers


217


such that the leading edge of a section of the thermal transfer recording web


202




a


is located at a print-starting position. Then, the feed rollers


217


are reversed and the thermal transfer recording web roll


202


is turned in a winding direction, i.e., a direction opposite to the direction of the arrow, to move the thermal transfer recording web


202




a


for printing in the direction opposite to the direction of the arrow.




The thermal transfer recording web


202




a


is extended tautly between the recording web feed unit


203


and the feed rollers


217


. An operation for feeding and winding the thermal transfer recording web


202




a


is controlled mainly by rotating the feed rollers


217


in the normal or the reverse direction. The drive rollers


210


and


211


rotates the thermal transfer recording web roll


202


in synchronism with the rotation of the feed rollers


217


to assist operations for feeding and winding the thermal transfer recording web


202




a


. Although it is therefore preferable that the thermal transfer recording web roll


202


does not slip relative to the drive rollers


210


and


211


, the thermal transfer recording web roll


202


may slip in some degree relative to the drive rollers


210


and


211


, provided that the thermal transfer recording web


2022




a


is neither creased nor folded.




The thermal transfer recording unit


205


is provided with a thermal transfer sheet


216


and a thermal head


214


. The thermal head


214


is brought into contact with the back surface of the thermal transfer sheet


216


. The thermal transfer recording web


202




a


is extended with its recording surface in contact with the surface coated with a transfer layer (the front surface) of the thermal transfer sheet


216


. A platen roller


215


is disposed opposite to the thermal head


214


so as to be in contact with the back surface of the thermal transfer recording web


202




a


. When printing an image by thermal transfer recording on the thermal transfer recording web


202




a


, the thermal head


214


is lowered in the direction of the arrow to transfer a color image from the thermal transfer sheet


216


to the thermal transfer recording web


202




a.






Preferably, guide members, not shown, are extended along the opposite side edges of the thermal transfer recording web


202




a


, respectively, between the recording web feed unit


203


and the thermal transfer recording unit


205


to prevent the thermal transfer recording web


202




a


from meandering.




Desirably, the distance between the guide members is adjustable according to the width of the thermal transfer recording web


202




a


. For example, pins and dice which engage with each other are attached to parts of the thermal transfer printer


201


to which the guide members are attached, the plurality of dice are attached to a member, and the member provided with the dice and a member provided with the pins are slid relative to each other. The pins are fitted in the dice located at positions corresponding to the width of the thermal transfer recording web


202




a


. Thus, the thermal transfer recording web


202




a


slides along the guide members, the guide members restrain the thermal transfer recording web


202




a


from lateral movement and hence the thermal transfer recording web


202




a


is prevented from meandering.




The cutting unit


209


cuts the printed thermal transfer recording web


202




a


into sheets. The printed thermal transfer recording web


202




a


may be taken up in a printed thermal transfer recording web roll.





FIG. 17

is an end view of the thermal transfer recording web roll


202


. As shown in

FIG. 17

, a thermal transfer recording web


202




a


is rolled in the thermal transfer recording web roll


202


. The end edge of the innermost layer


206


is bonded to a part


207


of the second innermost layer


207




a


of the thermal transfer recording web roll


202


with a bonding means, such as a double-coated adhesive tape, a liquid or solid adhesive or a sticky material, or the end edge of the innermost layer


206


may be covered and held on the second innermost layer with an adhesive tape. Adhesive strength between the end edge


207


of the innermost layer


206


and the second innermost layer is adjusted so that the end edge


207


of the innermost layer


206


is separated form the second innermost layer when the innermost layer


206


is pulled by the feed rollers


217


. Thus, all the thermal transfer recording web


202




a


of the thermal transfer recording web roll


202


can be used for printing, which is economically efficient and effective in reducing waste.




It is preferable, in view of avoiding adverse effect on thermal transfer recording, that the adhesive strength between the bonding means and the recording surface coated with a dye-recipient layer of the thermal transfer recording web


202




a


is lower than that between the bonding means and the back surface of the thermal transfer recording web


202




a.






It is still further preferable that the surface of the bonding means to be bonded to the dye-recipient layer of the thermal transfer recording web


202




a


is a tack-free surface which loses tackiness after being separated from the dye-recipient layer and does not make the dye-recipient layer tacky. The tack-free bonding means maybe latex of an acrylic resin, a rubber adhesive resin, a wax or a mixture of some of those. Naturally, the dye-recipient layer may be a tack-free layer. If the adhesive strength between the bonding means and the thermal transfer recording web


202




a


is far higher than a peeling force produced by torque applied to the thermal transfer recording web roll


202


by the drive rollers


210


and


211


, it is possible to find the exhaustion of the thermal transfer recording web roll


202


from a sharp change in the tension of the thermal transfer recording web


202




a


. Since the end edge of the innermost layer


206


of the thermal transfer recording web


202




a


is bonded to the part


207


of the second innermost layer


207




a


of the thermal transfer recording web roll


202


, the thermal transfer recording web roll


202


is a coreless roll having a bore


208


.




The two drive rollers


210


and


211


are inserted in the bore


208


of the thermal transfer recording web roll


202


and are pressed against the side surface


213


of the bore


208


. At least the drive roller


210


is driven for rotation to rotate the thermal transfer recording web roll


202


for thermal transfer printing.




The two drive rollers


210


and


211


shown in

FIG. 17

are driven by a driving mechanism included in the thermal transfer printer


201


. A gear, not shown, included in the thermal transfer printer


201


is driven for rotation. Then, the drive rollers


210


and


211


are rotated in the same direction as the gear of the thermal transfer printer


201


to rotate the thermal transfer recording web roll


202


. Consequently, the thermal transfer recording web


202




a


is fed for thermal transfer printing.




The drive rollers


210


and


211


may be interlocked by an interlocking member, not shown, so that the feed roller


211


may be rotated by the drive roller


210


when the drive roller


210


is driven for rotation. Thus, only the one drive roller


210


is driven to rotate both the drive rollers


210


and


211


.




The circumferences of the drive rollers


210


and


211


pressed against the inner surface


213


of the bore


208


of the thermal transfer recording web roll


202


are provided with small ridges or small knobs to prevent the drive rollers


210


and


211


from easily slipping relative to the thermal transfer recording web roll


202


.




According to the present invention, at least one of the drive rollers


210


and


211


pressed against the inner surface


213


of the bore


208


of the thermal transfer recording web roll


202


is driven to rotate the thermal transfer recording web roll


202


. The drive roller


211


maybe dragged for rotation by the thermal transfer recording web roll


202


when only the other drive roller


210


is driven for rotation. A slack in a segment of the thermal transfer recording web


202




a


extending between the drive rollers


210


and


211


can be taken up by braking drive roller


211


.




The tension of a segment of the thermal transfer recording web


202




a


pulled out from the thermal transfer recording web roll


202


held in the recording web feed unit


203


and extending between the recording web feed unit


203


and the feed rollers


217


can be properly adjusted by driving the drive roller


210


disposed in the bore


208


of the thermal transfer recording web roll


202


at a rotating speed which is relatively low as compared with the rotating speed of the feed rollers


217


.




FIGS.


18


(


a


) and


18


(


b


) are schematic views of an essential part of the thermal transfer printer


201


shown in FIG.


16


. As shown in

FIG. 18

, the center distance between the drive rollers


210


and


211


disposed in the bore


208


of the thermal transfer recording web roll


202


is changed according to the change of the outside diameter of the thermal transfer recording web roll


202


. Thus, the thermal transfer recording web roll


202


can be properly rotated by changing the presser applied by the drive rollers


210


and


211


to the inner surface


213


of the bore


208


, according to the hardness of the thermal transfer recording web roll


202


that changes as the thermal transfer recording web


202




a


is unwound.




A full thermal transfer recording web roll


202


as shown in FIG.


18


(


a


) has a large outside diameter, a long thermal transfer recording web


202




a


and a comparatively high hardness. When the full thermal transfer recording web roll


202


is loaded into the recording web feed unit


203


of the thermal transfer printer


201


, the drive rollers


210


and


211


are disposed in the bore


208


of the thermal transfer recording web roll


202


at a center distance c, and the inner surface


213


of the bore


208


in contact with the drive rollers


210


and


211


is cylindrical. Since the thermal transfer recording web roll


202


has a considerably high hardness, the thermal transfer recording web roll


202


is deformed scarcely when the drive rollers


210


and


211


are pressed against the side surface


213


of the bore


208


of the thermal transfer recording web roll


202


.




As the thermal transfer printer


201


expends the thermal transfer recording web


202




a


of the thermal transfer recording web roll


202


shown in FIG.


18


(


a


), the residual thermal transfer recording web


202




a


decreases and the outside diameter of the thermal transfer recording web roll


202


decreases as shown in FIG.


18


(


b


). The hardness of the thermal transfer recording web roll


202


shown in FIG.


18


(


b


) is comparatively low and hence the thermal transfer recording web roll


202


originally having the shape of a circular cylinder is deformed in the shape of an elliptic cylinder by the pressure applied thereto by the drive rollers


210


and


211


and hence the center distance between the drive rollers


210


and


211


is increased from c to d.




The pressure applied to the inner surface


213


of the bore


208


of the thermal transfer recording web roll


202


by the drive rollers


210


and


211


can be optionally adjusted by adjusting the center distance between the drive rollers


210


and


211


. Thus, the center distance between the drive rollers


210


and


211


is adjusted according to the change of the hardness of the thermal transfer recording web roll


202


as the thermal transfer recording web


202




a


is expended to ensure that the thermal transfer recording web roll


202


can be smoothly rotated.




Although the drive rollers


210


and


211


shown in FIGS.


18


(


a


) and


18


(


b


) are arranged on a horizontal line, the drive rollers


210


and


211


may be arranged on a vertical line, an oblique line or any suitable arrangement depending on the size and shape of the thermal transfer printer


201


so that the thermal transfer printer


201


is formed in compact construction.




The center distance between the drive rollers


210


and


211


disposed in the bore


208


of the thermal transfer recording web roll


202


is changed according to the change of the outside diameter of the thermal transfer recording web roll


202


so that the pressure applied properly to the inner surface


213


of the bore


208


by the drive rollers


210


and


211


may change properly according to the change of the hardness of the thermal transfer recording web roll


202


from the start of using the thermal transfer recording web


202




a


to the exhaustion of the thermal transfer recording web


202




a


to rotate the thermal transfer recording web roll


202


smoothly. Thus, the drive rollers


210


and


211


can be firmly pressed against the inner surface


213


of the bore


208


of the thermal transfer recording web roll


202


and the pressure applied to the inner surface


213


of the bore


208


can be properly changed according to the change of the length of the thermal transfer recording web


202




a


of the thermal transfer. recording web roll


202


. Consequently, the thermal transfer recording web roll


202


can be driven for rotation and controlled similarly to the conventional thermal transfer recording web roll formed by winding a thermal transfer recording web on a core.





FIG. 19

is a view of assistance in explaining another thermal transfer recording web roll


202


according to the present invention. As shown in

FIG. 19

, six drive rollers


210


,


210




a


,


210




b


,


211


,


211




a


and


211




b


are inserted in the bore


208


of the thermal transfer recording web roll


202


, and an endless belt


204


is extended around and is pressed against the inner surface


213


of the bore


208


by the drive rollers


210


,


210




a


,


210




b


,


211


,


211




a


and


211




b


. A central drive roller


212


is inserted in the bore


208


coaxially with the thermal transfer recording web roll


202


and is engaged with the six drive rollers


210


,


210




a


,


210




b


,


211


,


211




a


and


211




b.






Preferably, the drive rollers


210


,


210




a


,


210




b


,


211


,


211




a


and


211




b


and the central drive roller


212


are gears. The rotative driving force of the thermal transfer printer


201


is transmitted to the central drive roller


212


. The central drive roller


212


drives the endless belt


204


through the drive rollers


210


,


210




a


,


210




b


,


211


,


211




a


and


211




b


to feed the thermal transfer recording web


202




a


for thermal transfer printing. When the drive rollers


210


,


210




a


,


210




b


,


211


,


211




a


and


211




b


and the central drive roller


212


are gears, the endless belt


204


is provided in its inside surface with teeth capable of engaging with those of the drive rollers


210


,


210




a


,


210




b


,


211


,


211




a


and


211




b


and the central drive roller


212


.




Although the single endless belt


204


is disposed in the bore


208


of the thermal transfer recording web roll


202


shown in

FIG. 19

, a plurality of sets each of an endless belt and drive rollers for driving the endless belt may be arranged in the bore


208


of the thermal transfer recording web roll


202


along the axis of the thermal transfer recording web roll


202


.





FIG. 20

is a schematic sectional view of the recording web feed unit


203


of the thermal transfer printer


201


of the present invention and the associated parts. Drive rollers


210


and


211


are disposed in the bore


208


of the thermal transfer recording web roll


202


and are pressed against the side surface


213


of the bore


208


.




The drive rollers


210


and


211


have shafts


219


and


220


, and gears


221


and


222


are fixedly mounted on the shafts


219


and


220


, respectively. Compression springs


218


and


218




a


are extended between the shafts


219


and


220


. When inserting the drive rollers


210


and


211


in the bore


208


of the thermal transfer recording web roll


202


, force P is applied to the shafts


219


and


220


to reduce the center distance between the shafts


219


and


220


against the resilience of the compression springs


218


and


218




a


. The force P is removed from the shafts


219


and


220


after disposing the drive rollers


210


and


211


at predetermined positions in the bore


208


. Then, the drive rollers


210


and


211


are pressed against the inner surface


213


of the bore


208


of the thermal transfer recording web roll


202


by the resilience of the compression springs


218


and


218




a.






Although the two compression springs


218


and


218




a


are employed in the arrangement shown in

FIG. 20

, any suitable number of springs may be extended between any suitable positions on the shafts


219


and


220


to apply a proper pressure to the inner surface


213


of the bore


208


of the thermal transfer recording web roll


202


by the drive rollers


210


and


211


and to enable a proper force to reduce the center distance between the shafts


219


and


220


when inserting the drive rollers


210


and


211


in the bore


208


.




The gears


221


and


222


are engaged with a drive gear


223


which is driven by a rotative driving force of the thermal transfer printer


201


. The drive gear


223


drives the gears


221


and


222


for rotation to rotate the drive rollers


210


and


211


. The circumferences provided with small ridges or small knobs of the drive rollers


210


and


211


are pressed against the side surface


213


of the bore


208


of the thermal transfer recording web roll


202


to drive the thermal transfer recording web roll


202


for rotation.




Thus, the controlled rotative driving force of the thermal transfer printer


201


is transmitted to the thermal transfer recording web roll


202


to rotate the thermal transfer recording web roll


202


.




Although not shown in

FIG. 20

, a stopper may be put in contact with an end surface of the thermal transfer recording web roll


202


on the side of the gears


221


and


222


, or a stopper may be disposed in the recording web feed unit


203


of the thermal transfer printer


201


so as to be in contact with an end surface of the thermal transfer recording web roll


202


as held in the recording web feed unit


203


.




The position of the stopper is variable according to the length of the thermal transfer recording web roll


202


. The stopper and a member, such as a shaft to be used in combination with the stopper, are provided with a pin and plurality of dice, respectively. The pin is engaged with the die disposed at a position corresponding to the length of the thermal transfer recording web roll


202


so that the stopper comes into contact with one end surface of the thermal transfer recording web roll


202


. Two stoppers may be brought into contact with the opposite end surfaces of the thermal transfer recording web roll


202


to prevent the abrasion of the opposite end surfaces of the thermal transfer recording web roll


202


when the thermal transfer recording web roll


202


is rotated.




Although the thermal transfer recording web rolls


202


shown in

FIGS. 16

,


19


and


20


are provided with the two drive rollers, the seven drive rollers (the six of those rollers are used to press the endless belt


204


against the side surface


213


of the bore


208


), and the two drive rollers, respectively, the thermal transfer recording web roll according to the present invention may be provided with any suitable number of drive rollers and any suitable number of endless belts.




According to the present invention, it is important that the drive rolls


210


and


211


or the endless belt


204


do not slip relative to the side surface


213


of the bore


208


of the thermal transfer recording web roll


202


or the slip of the same relative to the side surface


213


of the bore


208


of the thermal transfer recording web roll


202


does not affect the quality of printed images. Preferably, the thermal transfer recording web


202




a


employed in the present invention has a base web, and a known dye-recipient layer formed on the base web and capable of receiving dyes from the color transfer layer of a thermal transfer sheet.




The drive rollers


210


and


211


and the like, and the endless belt


204


may be formed of the same material. Possible materials for forming the drive rollers


210


,


211


and the endless belt


204


are, for example, hydrogenated polybutadiene rubbers, butyl rubbers, isoprene rubbers, chloroprene rubbers, acrylic elastomers, urethane rubbers, silicone rubbers, fluororubbers, ethylene-propylene terpolymers (EPDMs), styrene-butadiene rubbers (SBRs), acrylonitrile butadiene rubbers (NBR) and a blend of some of these materials. The rubber material may be a thermoplastic elastomer. The urethane rubbers include polyester- and polyether-type thermoplastic polyurethane elastomers produced through polyaddition reaction between diisocyanate and a polyol.




Preferably, the surfaces to be brought into direct contact with the inner surface


213


of the bore


208


of the thermal transfer recording web roll


202


of the drive rollers


210


,


211


and the other drive rollers, and the endless belt


204


are provided with small ridges or small knobs formed in an optional pattern by a diamond-cutting process, a satin-finishing process or an embossing process. It is preferable to determine embossing depth, i.e., the height of projections of the small ridges or the small knobs, so that the endless belt


204


is able to exert a frictional resistance sufficient to prevent the thermal transfer recording web roll


202


from slipping relative to the endless belt


204


. For example, the embossing depth is in the range of about 5 to about 500 μm.




A thermal transfer recording method according to the present invention does not use any core. The innermost layer


206


of the thermal transfer recording web roll


202


is bonded to the part


207


of the second innermost layer


207




a


of the same, the drive rollers


210


and


211


are inserted in the bore


208


of the thermal transfer recording web roll


202


, and the center distance between the drive rollers


210


and


211


is adjusted optionally to press the drive rollers


210


and


211


against the side surface


213


of the bore


208


. At least the drive roller


210


is driven for rotation to rotate the thermal transfer recording web roll


202


for thermal transfer printing. The rotation of the feed rollers


217


is controlled to feed the thermal transfer recording web


202




a


, and the drive rollers


210


and


211


and the central drive roller


212


are rotated in synchronism with the rotation of the feed rollers


217


to rotate the thermal transfer recording web roll


202


according to the rotation of the feed rollers


217


to assist the operation for feeding the thermal transfer recording web


202




a


. Therefore, it is preferable that the thermal transfer recording web roll


202


does not slip relative to the drive rollers


210


and


211


. However, the thermal transfer recording web roll


2


may slip in some degree relative to the drive rollers


210


and


211


, provided that the thermal transfer recording web


2




a


is neither creased nor folded.




According to the present invention, the drive rollers


210


,


211


and the other drive rollers are set in contact with the side surface


213


of the bore


208


of the thermal transfer recording web roll


202


and, when necessary, the endless belt


204


is interposed between the side surface


213


of the bore


208


and the drive rollers


210


,


211


and the other drive rollers, so that the thermal transfer recording web roll


202


is hardly able to slip relative to the drive rollers


210


,


211


and the other drive rollers and the rotation of the thermal transfer recording web roll


202


can be surely controlled.




As apparent from the foregoing description, the thermal transfer printer according to the present invention uses the coreless thermal transfer recording web roll, and the innermost layer of the thermal transfer recording web roll is fixed to the second innermost layer of the thermal transfer recording web roll. The drive rollers are inserted in the bore of the thermal transfer recording web roll, the center distance between the drive rollers is adjusted optionally to press the drive rollers against the side surface of the bore. At least one of the drive rollers is driven for rotation to rotate the thermal transfer recording web roll for thermal transfer printing. Thus, any core is not necessary for holding the thermal transfer recording web roll, the thermal transfer recording web roll can be prepared at a low cost without requiring much time and effort, and an image of an excellent image quality can be formed by thermal transfer printing.




Fourth Embodiment





FIGS. 21

to


25


are schematic views of a fourth embodiment of the present invention. Referring to

FIG. 21

, a thermal transfer printer


301


has a thermal transfer recording web roll


302


formed by rolling a thermal transfer recording web


302




a


, a recording web feed unit


303


provided with a rotative driving device (rotative driving mechanism)


304


for rotating the thermal transfer recording web roll


302


, a thermal transfer recording unit


305


, and a cutting unit


310


for cutting the thermal transfer recording web


302




a


into sheets.




The thermal transfer recording web


302




a


is pulled out from the recording web feed unit


303


by feed rollers


316


in the direction of the arrow such that the leading edge of a section of the thermal transfer recording web


302




a


is located at a print-starting position. Then, the feed rollers


316


are reversed and the thermal transfer recording web roll


302


is turned in a winding direction to move the thermal transfer recording web


302




a


for printing in a direction opposite to the direction of the arrow. The thermal transfer recording web


302




a


is extended tautly between the rotative driving device


304


and the feed rollers


316


. An operation for feeding and winding the thermal transfer recording web


302




a


is controlled mainly by rotating the feed rollers


316


in the normal or the reverse direction. The rotative driving device


304


is interlocked with the feed rollers


316


so as to rotate the thermal transfer recording web roil


302


according to the rotations the feed rollers


316


to unwind or wind the thermal transfer recording web


302




a


subordinately to the operation of the feed rollers


316


. Although it is preferable that the thermal transfer recording web roll


302


does not slip relative to the rotative driving device


304


, the thermal transfer recording web roll


302


may slip in some degree relative to the rotative driving device


304


, provided that the thermal transfer recording web


302




a


is neither folded nor creased.




The thermal transfer recording unit


305


is provided with a thermal transfer sheet


315


and a thermal head


313


. The thermal head


313


is brought into contact with the back surface of the thermal transfer sheet


315


. The thermal transfer recording web


302




a


is extended with its recording surface in contact with the surface coated with a transfer layer (the front surface) of the thermal transfer sheet


315


. A platen roller


314


is disposed opposite to the thermal head


313


so as to be in contact with the back surface of the thermal transfer recording web


302




a


. When printing an image by thermal transfer recording on the thermal transfer recording web


302




a


, the thermal head


313


is lowered in the direction of the arrow to transfer a color image from the thermal transfer sheet


315


to the thermal transfer recording web


302




a.






Preferably, two guide members, not shown, are extended along the opposite side edges of the thermal transfer recording web


302




a


, respectively, between the recording web feed unit


303


and the thermal transfer recording unit


305


to prevent the thermal transfer recording web


302




a


from meandering.




Desirably, the distance between the two guide members is adjustable according to the width of the thermal transfer recording web


302




a


. For example, pins and dice which engage with each other are attached to parts of the thermal transfer printer


301


to which the guide members are attached, the plurality of dice are attached to a member, and the member provided with the dice and a member provided with the pins are slid relative to each other. The pins are fitted in the dice located at positions corresponding to the width of the thermal transfer recording web


302




a


. Thus, the thermal transfer recording web


302




a


slides along the guide members, the guide members restrain the thermal transfer recording web


302




a


from lateral movement and hence the thermal transfer recording web


302




a


is prevented from meandering.




The cutting unit


310


of the thermal transfer printer


301


cuts the thermal transfer recording web


302




a


into sheets. The printed thermal transfer recording web


302




a


may be taken up in a printed thermal transfer recording web roll.





FIG. 22

is a schematic, fragmentary sectional view of the thermal transfer printer of the present invention, showing the assembly of the thermal transfer recording web roll


302


held in the recording web feed unit


303


, and the rotative driving device


304


. The rotative driving device


304


includes a pair of disks (rotative driving members)


318


each having a tapered side surface


319




c


. An inner peripheral part


319


of each disk


318


of the rotative driving device


304


is pressed against an inner peripheral part


317


of each end surface of the thermal transfer recording web roll


302


. The thermal transfer printer


301


drives the rotative driving device


304


to rotate the disks


318


in the normal or the reverse direction for thermal transfer printing, and the thermal transfer recording web roll


302


is rotated accordingly. A compression spring


308


is compressed between one of the disks


318


and a flange


320


disposed on the outer side of the disk


318


to press the disks


318


against the opposite end surfaces


322


of the thermal transfer recording web roll


302


.




Preferably, the taper angle of the tapered side surface


319




c


, to be pressed against the end surface of the thermal transfer recording web roll


302


, of each disk


318


is in the range of about 5° to about 20°. The side surface


319




c


of each disk


318


does not necessarily need to be tapered; the inner side surface may be a flat surface parallel to the corresponding end surface of the thermal transfer recording web roll


302


. The side surfaces


319




c


of the disks


318


of the rotative driving device


304


do not need necessarily to be pressed against the end surfaces of the thermal transfer recording web roll


302


; a shaft


321


included in the rotative driving device


304


may be provided with externally threaded parts, the disks


318


and the flanges


320


may be provided with internally threaded holes, and the disks


318


and the flanges


302


may be screwed on the externally threaded parts of the shaft


321


, respectively.




FIGS.


24


(


a


) and


24


(


b


) are sectional views of a rotative driving device having parts pressed against the end surfaces of the thermal transfer recording web roll according to the present invention. Referring to FIG.


24


(


a


), a disk


318




b


is put on a shaft


321


provided with a flange


320




b


so as to rest on the flange


320




b


. The shaft


321


is inserted in the bore


309


of the thermal transfer recording web roll


302


through an open end of the bore


309


on the side of an end surface


322




b


of the thermal transfer recording web roll


302


and is pushed in the direction of the arrow so that an end part thereof project from the other open end, on the side of the other end surface


322




a


of the thermal transfer recording web roll


302


, of the bore


309


. The assembly of a disk


318




a


and a flange


320




a


having a bore


323




a


is put on the end part of the shaft


321


projecting from the end surface


322




a


. Thus, the disks


318




a


and


318




b


are pressed against the opposite end surfaces


322




a


and


322




b


of the thermal transfer recording web roll


302


, respectively, as shown in FIG.


24


(


b


).




The thermal transfer recording web roll


302


and the rotative driving device


304


are engaged frictionally so as to rotate in a body for thermal transfer printing. Although it is preferable that the thermal transfer web roll


302


does not slip relative to the rotative driving device


304


, the thermal transfer recording web roll


302


may slip in some degree relative to the rotative driving device


304


, provided that the slip of the thermal transfer recording web roll


302


relative to the rotative driving device


304


does not affect adversely to image quality.





FIG. 23

is an end view of the thermal transfer recording web roll


302


. As shown in

FIG. 23

, the thermal transfer recording web roll


302


formed by rolling a thermal transfer recording web. The end edge of the innermost layer


306


is bonded to a part


307


of the second innermost layer


307




a


of the thermal transfer recording web roll


302


with a bonding means, such as a double-coated adhesive tape or a liquid or solid adhesive, or the end edge of the innermost layer


306


may be covered and held on the second innermost layer with an adhesive tape. The thermal transfer recording web roll


302


is a coreless roll having a bore


309


. The thermal transfer recording web roll


302


is held between the disks


318


of the rotative driving device


304


shown in FIG.


22


. The disks


318


are pressed against the opposite end surfaces of the thermal transfer recording web roll


302


, respectively, and rotate together with the thermal transfer recording web roll


302


for thermal transfer printing.




As shown in

FIGS. 24 and 25

, the distance between the respective side surfaces


318




c


of the disks


318




a


and


318




b


can be changed according to the length of the thermal transfer recording web roll


302


, i.e., the width of the thermal transfer recording web


302




a


. The printed thermal transfer recording web


302




a


is cut into sheets of a standard trim size, such a standard trim size A3, B3, A4, B4, A5 or B5. In most cases, the thermal transfer recording web


302




a


of the thermal transfer recording web roll


302


has a width equal to the that of a sheet of a selected standard trim size, such as a standard trim size A4, obtained by cutting the thermal transfer recording web


302




a


, and the printed thermal transfer recording web


302




a


is cut in a length equal to that of the sheet of the selected standard trim size.




When adjusting the distance between the disks


318


mounted on the shaft


321


of the rotative driving device


304


, i.e., the working length of the shaft


321


, to combine a thermal transfer recording web roll


302


having a comparatively long length, a pin


312




b


projecting from the side surface of the bore


323




b


of the disk


318




b


is engaged in a notch t


2


formed in a groove


311




b


formed in the shaft


321


(FIGS.


24


(


b


) and


25


(


a


)) to determine the position of the flange


318




b


on the shaft


321


. Subsequently, a pin


312




a


projecting from the side surface of the bore


323




a


of the flange,


320




a


is engaged in a notch s


1


formed in a groove


311




a


formed in the shaft


321


(FIGS.


24


(


b


) and


25


(


a


)) to determine the position of the flange


320




a


on the shaft


321


. The compression spring


308


compressed between the flange


320




a


and the disk


318




a


presses the disk


318




a


against the end surface of the thermal transfer recording web roll


302


. Thus, the,thermal transfer recording web roll


302


having a comparatively long length is combined with the rotative driving device


304


.




When adjusting the distance between the disks


318


, i.e., the working length of the shaft


321


, to combine a thermal transfer recording web roll


302


having a comparatively short length, the pin


312




b


projecting from the side surface of the bore


323




b


of the disk


318




b


is engaged in a notch t


1


formed in the groove


311




b


formed in the shaft


321


as shown in FIG.


25


(


b


) to determine the position of the flange


318




b


on the shaft


321


. Subsequently, the pin


312




a


projecting from the side surface of the bore


323




a


of the flange


320




a


is engaged in a notch s


2


formed in the groove


311




a


formed in the shaft


321


to determine the position of the flange


320




a


on the shaft


321


. The compression spring


309


compressed between the flange


320




a


and the disk


318




a


presses the disk


318




a


against the end surface of the thermal transfer recording web roll


302


.




Preferably, symbols indicating standard trim sizes, such as A4 and A5, are marked in the surface of the shaft


321


at positions near the notches for the standard trim sizes, respectively, to facilitate operations for adjusting the distance between the disks


318




a


and


318




b.






The rotative driving devices shown in

FIGS. 22

,


24


and


25


press the disks


308


against the end surfaces of the thermal transfer recording web roll


302


. The thermal transfer recording web roll


302


and the rotative driving device


304


can be securely joined together by fitting the shaft


321


in the bore


309


of the thermal transfer recording web roll


302


so that the surface of the shaft


321


is in close contact with the side surface of the bore


309


. When thus combining the rotative driving device


304


and the thermal transfer recording web roll


302


, it is preferable to form a part, on the side of the disk


318




b


, of the shaft


321


in a diameter greater than that of other part of the same to increase the pressure to be applied to the side surface of the bore


309


by the shaft


321


.




According to the present invention, it is important that the rotative driving device


304


does not slip relative to the thermal transfer recording web roll


302


or the slip of the holding device


304


relative to the thermal transfer recording web roll


302


does not affect the quality of printed images. Preferably, the thermal transfer recording web


302




a


employed in the present invention has a base web, and a dye-recipient layer formed on the base web and capable of receiving dyes from the color transfer layer of a thermal transfer sheet.




The disks


318


,


318




a


and


318




b


of the rotative driving device


304


of the thermal transfer printer according to the present invention may be formed of a durable metal, such as aluminum, iron or a stainless steel or may be formed of a resin, such as a polystyrene resin, a vinyl chloride resin, a polycarbonate resin or a polyester resin, by injection molding. Preferably, the surfaces of the disks


318


,


318




a


and


318




b


to be brought into direct contact with the thermal transfer recording web roll


302


are provided with small ridges or small knobs formed in an optional pattern by a diamond-cutting process, a satin-finishing process or an embossing process. It is preferable to determine embossing depth, i.e., the height of projections of the irregularities, such that the holding device is able to exert a frictional resistance sufficient to prevent the thermal transfer recording web roll


302


from slipping relative to the disks


318


,


318




a


and


318




b


. For example, the embossing depth is in the range of about 5 to about 500 μm.




A thermal transfer recording method according to the present invention does not use any core. The innermost layer


306


of the thermal transfer recording web roll


302


is bonded to the second innermost layer of the thermal transfer recording web roll


302


, the thermal transfer recording web roll


302


is held by the rotative driving device


304


, and the holding device


304


and the thermal transfer recording web roll


302


are rotated in a body for thermal transfer printing. The rotation of the feed rollers


316


is controlled to feed the thermal transfer recording web


302




a


, and the rotative driving device


304


rotates the thermal transfer recording web roll


302


according to the rotation of the feed rollers


316


to assist the operation for feeding the thermal transfer recording web


302




a


. Therefore, it is preferable that the thermal transfer recording web roll


302


does not slip relative to the rotative driving device


304


. However, the thermal transfer recording web roll


302


may slip in some degree relative to the rotative driving device


304


, provided that the thermal transfer recording web


302




a


is neither creased nor folded.




According to the present invention, the thermal transfer recording web roll


302


and the rotative driving device


304


are hardly able to slip relative to each other, and the rotation of the thermal transfer recording web roll


302


can be surely controlled.




As apparent form the foregoing description, the thermal transfer printer according to the present invention uses the coreless thermal transfer recording web roll, and the innermost layer of the thermal transfer recording web roll is fixed to the second innermost layer of the thermal transfer recording web roll. The rotative driving device is combined with the thermal transfer recording web roll. Since the thermal transfer recording web roll rotates together with the holding device, any core is not necessary for holding the thermal transfer recording web roll, the thermal transfer recording web roll can be prepared at a low cost without requiring much time and effort, and an image of an excellent image quality can be formed by thermal transfer printing.




Fifth Embodiment





FIGS. 26

to


34


are schematic views of a fifth embodiment of the present invention. Referring to

FIG. 26

, a thermal transfer printer


401


has a coreless recording web roll


402


formed by rolling a thermal transfer recording web


402




a


, a recording web feed unit


403


holding the recording web roll


402


, a pair of flanged tubular shafts


410


and


411


holding the recording web roll


402


and respectively provided with slits


418




a


and


418




b


, a thermal transfer recording unit


405


that operates for thermal, transfer recording, and a cutting unit


409


for cutting the thermal transfer recording web


402




a


into sheets.




The recording web roll


402


is formed by rolling the thermal transfer recording web


402




a


, and has an innermost layer


406


the recording web roll


402


and bonded to the second innermost layer


407




a


of the recording web roll


402


.




The thermal transfer recording web


402




a


is pulled out from the recording web feed unit


403


by feed rollers


417


in the direction of the arrow such that the leading edge of a section of the thermal transfer recording web


402




a


is located at a print-starting position. Then, the feed rollers


417


are reversed and the thermal transfer recording web roll


402


is turned in a winding direction to move the thermal transfer recording web


402




a


for printing in a direction opposite to the direction of the arrow. The thermal transfer recording web


402




a


is extended tautly between the flanged tubular shafts


410


and


411


, and the feed rollers


417


. An operation for feeding and winding the thermal transfer recording web


402




a


is controlled mainly by rotating the feed rollers


417


in the normal or the reverse direction. The flanged tubular shafts


410


and


411


is interlocked with the feed rollers


417


so as to rotate the thermal transfer recording web roll


402


according to the rotation of the feed rollers


417


to unwind or wind the thermal transfer recording web


402




a


subordinately to the operation of the feed rollers


417


. Although it is preferable that the thermal transfer recording web roll


402


does not slip relative to the flanged tubular shafts


410


and


411


, the thermal transfer recording web roll


402


may slip in some degree relative to the flanged tubular shafts


410


and


411


, provided that the thermal transfer recording web


402




a


is neither folded nor creased.




The thermal transfer recording unit


405


is provided with a thermal transfer sheet


416


and a thermal head


414


. The thermal head


414


is brought into contact with the back surface of the thermal transfer sheet


416


. The thermal transfer recording web


402




a


is extended with its recording surface in contact with the surface coated with a transfer layer (the front surface) of the thermal transfer sheet


416


. A platen roller


415


is disposed opposite to the thermal head


414


so as to be in contact with the back surface of the thermal transfer recording web


402




a


. When printing an image by thermal transfer recording on the thermal transfer recording web


402




a


, the thermal head


414


is lowered in the direction of the arrow to transfer a color image from the thermal transfer sheet


416


to the thermal transfer recording web


402




a.






Preferably, two guide members, not shown, are extended along the opposite side edges of the thermal transfer recording web


402




a


, respectively, between the recording web feed unit


403


and the thermal transfer recording unit


405


to prevent the thermal transfer recording web


402




a


from meandering.




Desirably, the distance between the two guide members is adjustable according to the width of the thermal transfer recording web


402




a


. For example, pins and dice which engage with each other are attached to parts of the thermal transfer printer


401


to which the guide members are attached, the plurality of dice are attached to a member, and the member provided with the dice and a member provided with the pins are slid relative to each other. The pins are fitted in the dice located at positions corresponding to the width of the thermal transfer recording web


402




a


. Thus, the thermal transfer recording web


402




a


slides along the guide members, the guide members restrain the thermal transfer recording web


402




a


from lateral movement and hence the thermal transfer recording web


402




a


is prevented from meandering.




The cutting unit


409


of the thermal transfer printer


401


cuts the thermal transfer recording web


402




a


into sheets. The printed thermal transfer recording web


402




a


may be taken up in a printed thermal transfer recording web roll.




FIGS.


27


(


a


) and


27


(


b


) are views of assistance in explaining a method of fitting the flanged tubular shafts


410


and


411


on the thermal transfer recording web roll


402


. FIG.


27


(


a


) shows a state before the flanged tubular shafts


410


and


411


are fitted in the central


408


of the thermal transfer recording web roll


402


. The flanged shafts


410


and


411


are provided with slits


418




a


and


418




b


and flanges


412




a


and


412




b


, respectively. The flanged tubular shafts


410


and


411


are provided with gears


420


, which are engaged with gears, not shown, of the thermal transfer printer


401


. Only the flanged shaft


411


may be provided with the gear


420


. The thermal transfer recording web roll


402


is formed by rolling the thermal transfer recording web


402




a


without using any core and has an inner end segment


419


. The inner end segment


419


may be formed by either of two rolling methods. In one of the rolling methods the inner end segment


419


forming the innermost layer of the recording web roll


402


is bent at a part


407


which is at an optional distance from the inner end edge


423


of the thermal transfer recording web


402




a


in a direction perpendicular to the rolling direction, before rolling the thermal transfer recording web


402




a


. In another rolling method, the thermal transfer recording web roll


402


is formed first, and then the inner end segment


419


is bent at a part


407


which is at an optional distance from the inner end edge


423


of the thermal transfer recording web


402




a


. The part


407


is bonded to the second innermost layer


407




a


of the thermal transfer recording web roll


402


.




The positions of the flanged tubular shafts


410


and


411


are adjusted so that the slits


418




a


and


418




b


thereof correspond to the inner end segment


419


of the thermal transfer recording web roll


402


, and then the flanged tubular shafts


410


and


411


are inserted in the directions of the arrows, respectively, into the central bore


408


as far as the inner surfaces of the of the flanges


412




a


and


412




b


come into contact with the end surfaces


441


and


442


of the thermal transfer recording web roll


402


, respectively. A tubular part


425


of the flanged tubular shaft


410


is fitted in the tubular part


424


of the flanged tubular shaft


411


. Consequently, the flanged tubular shafts


410


and


411


are fitted on the thermal transfer recording web roll


402


as shown in FIG.


27


(


b


).




Subsequently, the flanged tubular shafts


410


and


411


are turned in opposite directions, respectively, to hold the inner end segment


419


of the thermal transfer recording web roll


402


between the slits


418




a


and


418




b


, and then the flanged tubular shaft


411


is turned in a direction in which the thermal transfer recording web


402




a


is wound to form the thermal transfer recording web roll


402


to tighten the thermal transfer recording web roll


402


. Consequently, the thermal transfer recording web roll


402


having the inner end part


419


and the flanged shafts


410


and


411


are united firmly together.




As shown in

FIG. 27

, the flange tubular shaft


410


has the flange


412




a


to be brought into contact with the end surface


441


of the thermal transfer recording web roll


402


, and the tubular part


425


provided with the slit


418




a


and to be inserted in the central bore


408


of the thermal transfer recording web roll


402


, and the flanged tubular shaft


411


has the flange


412




b


to be brought into contact with the end surface


442


of the thermal transfer recording web roll


402


, the tubular part


418




b


provided with the slit


418




b


and to be inserted in the bore


408


of the thermal transfer recording web roll


402


, and the gear


420


. Only the flanged tubular shaft


411


may be provided with the gear


420


as shown in

FIG. 27

, or both the flanged tubular shafts


410


and


411


may be provided with the gears


420


, the rotative driving force of the thermal transfer printer


401


may be transmitted through the flanged tubular shafts


410


and


411


to rotate the thermal transfer recording web roll


402


.




The flanges


412




a


and


412




b


of the flanged tubular shafts


410


and


411


shown in

FIG. 27

may be provided in their circumferences with gear teeth and the gears


420


may be omitted, and each of the tubular parts


425


and


426


may be provided with a plurality slits.




When the flanged tubular shaft


410


and


411


are used for supporting. thermal transfer recording web rolls of thermal transfer recording webs respectively having different widths, the length f of the slits


418




a


and


418




b


of the flanged tubular shafts


410


and


411


must be adjustable, and the distance between the inner side surfaces of the flanges


412




a


and


412




b


must be adjusted to a value not smaller than the width of the thermal transfer recording web.




FIGS.


28


(


a


) to


28


(


f


) are end views of assistance in explaining a process in which the inner end segment


419


of innermost layer


406


of the thermal transfer recording web roll


402


is held between the flanged shafts


410


and


411


.




As shown in FIG.


28


(


a


), the segment


419


of the thermal transfer recording web roll


402


is bent at the part


407


perpendicularly to the rolling direction. The tubular parts


425


and


426


of the flanged tubular shafts


410


and


411


are inserted into the opposite end segment of the central bore


408


of the thermal transfer recording web roll


402


with the slits


418




a


and


418




b


of the flanged tubular shafts


410


and


411


aligned with each other so that the inner end segment


419


is extended through the slits


418




a


and


418




b


. The inner end segment


419


extends through the substantially middle parts of the slits


418




a


and


418




b


of the flanged tubular shafts


410


and


411


. Preferably, the inner end segment


419


is long and the length of the same is substantially equal to the half of the inside diameter of the tubular part


426


of the flanged shaft


411


.




Then, as shown in FIG.


28


(


b


), the flanged tubular shaft


410


is turned in the direction of the arrow relative to the flanged tubular shaft


411


to hold the inner end segment


419


between the flanged tubular shafts


410


and


411


. The flanged tubular shaft


410


can be turned through the gear


420


thereof by the thermal transfer printer


401


.




The flanged tubular shaft


410


is turned further relative to the flanged tubular shaft


411


to a position shown in FIG.


28


(


c


).




Then the flanged tubular shaft


411


is turned from a position shown in FIG.


28


(


c


) in the direction of the arrow shown in FIG.


28


(


d


) relative to the flanged shaft


410


to wind the thermal transfer recording web roll


402


tight. The flanged shaft


411


can be thus turned through the gear


420


by the thermal transfer printer


401


.




Then, the flanged shaft


411


is turned further from a position shown in FIG.


28


(


d


) in the direction of the arrow vie a state shown in FIG.


38


(


e


) to a state shown in FIG.


28


(


f


). In the state shown in FIG.


28


(


f


), the innermost layer of the thermal transfer recording web roll


402


is in close contact with the tubular part


426


of the flanged shaft


411


and the flanged shaft


411


cannot be turned any further.




Thus the inner end segment


406


of the thermal transfer recording web roll


402


is in close contact with the tubular part


426


of the flanged tubular shaft


411


, and the flanged shafts


410


and


411


are fastened firmly to the thermal transfer recording web


402


, so that the thermal transfer recording web roll


402


is able to be turned together with the flanged shafts


410


and


411


. Desirably, a gap between the respective tubular parts


425


and


426


of the flanged shafts


410


and


411


is slightly greater than the thickness of the thermal transfer recording web


402




a


by a value, for example, in the range of several micrometers to several tens micrometers.




The gap d is formed between the respective tubular parts


425


and


426


of the flanged shafts


410


and


411


because the outside diameter of the tubular part


425


of the flanged shaft


410


and the inside diameter of the tubular part


426


of the flanged shafts


411


are different. Although the flanged shafts


410


and


411


can be fastened together when the gap d is small, the flanged shaft


411


cannot be easily turned relative to the flanged shaft


410


to wind the thermal transfer recording web roll


402


tight if the gap d is excessively small. If the gap d is excessively big, the tubular part


425


of the flanged shaft


410


rattles in the tubular part


426


of the flanged shaft


411


, and the flanged shafts


410


and


411


are combined eccentrically. Consequently, problems arise in the accuracy of rotating the thermal transfer recording web roll


402


to feed the thermal transfer recording web


402




a


and driving the thermal transfer recording web roll


402


by the thermal transfer printer. The




The gap can be adjusted properly by forming the tubular part


425


of the flanged shaft


410


in a proper outside diameter and forming the tubular part


426


of the flanged tubular shaft


411


in a proper inside diameter. Flanged tubular shafts


410


and


411


shown in

FIG. 31

are so designed as to prevent the tubular parts thereof from rattling relative to each other. The flanged tubular shaft


411


is provided with a central rod


427


, and the flange of the flanged shaft


410


is provided with a central bore


431


. The flanged shaft


411


is fitted in the bore of a thermal transfer recording web roll


402


and the free end part of the central rod


427


is fitted in the central hole


431


of the flange of the flanged shaft


410


to prevent the tubular parts of the flanged shafts


410


and


411


from rattling relative to each other. Flanged tubular shafts


410


and


411


shown in

FIG. 34

may be used. If a big gap d is formed between the tubular parts


425


and


426


of the flanged shafts


410


and


411


, a circular ring


434


is formed on the inner side surface of the flange


412




b


of the flanged shaft


411


, and the free end of the tubular part


425


of the flanged shaft


410


is fitted in the circular ring


434


. Since the position of the flanged shaft


410


relative to the flanged shaft


411


is fixed by the ring


434


, the flanged shafts


410


and


411


are prevented from rattling while the same are rotated.




The respective widths e


1


and e


2


of slits


418




a


and


418




b


formed in the tubular parts


425


and


426


of the flanged shafts


410


and


411


are determined so that the inner end part


419


of the thermal transfer recording web


402




a


can be held between the flanged shafts


410


and


411


when the flanged shafts


410


and


411


are turned relative to each other. Generally, it is proper that the thickness of the thermal transfer recording web


402




a


is far less than the width e


2


of the flanged shaft


411


, and the width e


2


is not greater than the width e


1


of the slit


418




a


of the flanged shaft


410


.




Preferably, a perforated line or a pressed line is formed in the part


407


of the inner end segment


406


to facilitate bending the inner end segment


406


in a radial direction along the part


407


.





FIG. 29

is a view of assistance in explaining a state in which an inner end segment


419


of a thermal transfer recording web roll


402


is held between flanged shafts


410


and


411


, which are different from those shown in FIG.


28


.




Referring to

FIG. 29

, the inner end segment


419


of the thermal transfer recording web roll


402


is passed through slits


418




a


and


418




b


formed respectively in the tubular parts of the flanged shafts


410


and


411


, the flanged shaft


410


is turned clockwise and the flanged shaft


411


is turned counterclockwise. In this state, parts of an inner end part


419


corresponds to edges


428


and


429


of the tubular part of the flanged shafts


411


and an edge


430


of the tubular part of the flanged shaft


410


. Thus, the inner end segment


419


is pulled when the flanged shaft


411


is turned counterclockwise.




Then, the flanged shaft


410


is turned clockwise to pull the inner end part


419


and the flanged shaft


411


is turned in a winding direction to wind the thermal transfer recording web roll


402


tight. Consequently, the inner end segment


419


of the thermal transfer recording web roll


402


is fastened to the flanged shafts


410


and


411


. Since the inner end segment


419


is bent at comparatively sharp angles by the edges


428


and


430


in the state shown in

FIG. 29

, friction between the inner end segment


419


and the flanged shafts


410


and


411


is high and hence the thermal transfer recording web roll


402


can be fastened more firmly to the flanged shafts


410


and


411


than that shown in FIG.


28


.





FIG. 30

is a schematic view of a thermal transfer recording web roll


402


according to the present invention loaded into a thermal transfer printer


401


. A shaft


421




a


projecting from the flanged shaft


410


is supported for rotation on a support member


422




a


of the thermal transfer printer


401


, and a shaft


421




b


projecting from the flanged shaft


411


is supported for rotation on a support member


422




b


of the thermal transfer printer


401


. A drive gear, not shown, of the thermal transfer printer is engaged with a gear


420


attached to the flanged shaft


411


to drive the thermal transfer recording web roll


402


for rotation. Since the flanged shafts


410


and


411


are supported for rotation on the support members


422




a


and


422




b


of the thermal transfer printer


401


, the thermal transfer recording web roll


202


does not make eccentric rotation. The respective flanges


412




a


and


412




b


of the flanged shafts


410


and


444


are pressed against the opposite end surfaces


441


and


442


of the thermal transfer recording web roll


402


to protect the end surfaces


441


and


442


from abrasion when the thermal transfer recording web roll


402


is rotated.




As shown in

FIG. 30

, the respective tubular parts


425


and


426


of the flanged shafts


410


and


411


are inserted in the bore


408


of the thermal transfer recording web roll


402


. The outside diameter of the tubular part


426


of the flanged shaft


411


is smaller than the diameter of the bore


408


of the thermal transfer recording web roll


402


by a value in the range of several micrometers to several tens micrometers. The outside diameter of the tubular part


425


of the flanged shaft


410


is smaller than the inside diameter of the tubular part


426


of the flanged shaft


411


by a value in the range of several micrometers to several tens micrometers. Thus the tubular part


426


of the flanged shaft


411


comes into contact with the inner surface of the bore


408


when the same is inserted in the bore


408


. The tubular part


425


of the flanged shaft


410


is inserted into the tubular part


426


of the flanged shaft


411


. The respective tubular parts


425


and


426


of the flanged shafts


410


and


411


are provided with slits


418




a


and


418




b


, respectively. The inner end segment


419


of the thermal transfer recording web


402




a


of the thermal transfer recording web roll


402


is inserted in the slits


418




a


and


418




b


of the flanged shafts


410


and


411


, the flanged shafts


410


and


411


are turned in opposite directions, respectively, to hold the inner end segment


419


firmly between the flanged shafts


410


and


411


.




When the flanged shaft


410


and


411


are used for supporting thermal transfer recording web rolls of thermal transfer recording webs respectively having different widths, the length f of the slits


418




a


and


418




b


of the flanged shafts


410


and


411


may be adjustable, a mark indicating a correct position for the inner end part


419


maybe formed in the tubular part


426


of the flanged shaft


411


or slits


418




b


of lengths corresponding to the sizes of different thermal transfer recording web rolls


402


may be formed only in the flanged shaft


411


at greatest possible angular intervals. The slits


418




a


of the flanged shaft


410


may be formed so as to conform to the greatest one of the widths of the thermal transfer recording webs to be used and the slit


418




a


of the flanged shaft


410


may be aligned with the slit


418




b


of the flanged shaft


411


conforming to the size of the thermal transfer recording web to be used among those formed in the tubular part


426


of the flanged shaft


411


.





FIG. 31

is a view of assistance in explaining a method of putting a flanged shaft


411


provided with a central rod


427


on a thermal transfer recording web roll


402


according to the present invention. The flanged shaft


411


is provided with the central rod


427


, and the other flanged shaft


410


is provided with a hole


431


to receive an end part of the central rod


427


. Thus, the flanged shafts


410


and


411


can be correctly combined by fitting the end part of the central rod


427


of the flanged shaft


411


in the hole


431


of the other flanged shaft


410


. The center rod


427


may be locked in place by a locking means after the end part thereof has been fitted in the hole


431


to restrain the flanged shafts


410


and


411


from movement relative to each other.




FIGS.


32


(


a


) to


32


(


d


) are views of assistance in explaining a procedure for winding a thermal transfer recording web


402




a


to form a thermal transfer recording web roll


402


.




Referring to FIG.


32


(


a


), a winding shaft


432


is divided into four parts spaced by gaps. An inner edge


423


of the thermal transfer recording web


402




a


is inserted in one of the gaps of the winding shaft


432


. At this stage, the winding shaft


432


expands in a big diameter because any high compressive force is not exerted on the winding shaft


432


.




As shown in FIG.


32


(


b


), the thermal transfer recording web


402




a


is pressed against the circumference of the winding shaft


432


by a pressure roller


433


and is wound around the winding shaft


432


to form a thermal transfer recording web roll


402


. The winding shaft


432


is compressed radially as indicated by the arrows in FIG.


32


(


c


). Then, the winding shaft


432


is extracted from the thermal transfer recording web roll


402


to provide a coreless thermal transfer recording web


402


having a free inner end segment


419


.




FIGS.


33


(


a


) to


33


(


d


) are views of assistance in explaining another procedure for winding a thermal transfer recording web


402




a


to form a thermal transfer recording web roll


402


.




Referring to FIG.


33


(


a


), winding shafts


432




a


and


432




b


are supported on a rotary mechanism at a fixed center distance. A thermal transfer recording web


402




a


is extended between the winding shafts


432




a


and


432




b


so that an inner end segment


419


extends beyond the winding shaft


432




b


. Then, the rotary mechanism turns the winding shafts


432




a


and


432




b


about an axis passing the middle point between the center axes of the winding shafts


432




a


and


432




b


to wind the thermal transfer recording web


402




a


in a loop as shown in FIG.


33


(


b


).




Then, as shown in FIG.


33


(


c


), the center distance between the winding shafts


432




a


and


432




b


is reduced and the winding shafts


432




a


and


432




b


are extracted from the loop to provide a coreless thermal transfer recording web roll


402


having the free inner end part


419


as shown in FIG.


33


(


d


).




According to the present invention, it is important that the inner end segment


419


of the thermal transfer recording web roll


402


is firmly fastened to the flanged shafts


410


and


411


so that the inner end segment


419


does not slip relative to the flanged shafts


410


and


411


or slips in some degree that does not affect print quality. Preferably, the thermal transfer recording web


402




a


employed in the present invention is provided with a conventional dye-recipient layer capable of receiving and fixing dyes.




Preferably, the flanged shafts


410


and


411


are formed of a resin suitable for injection molding, such as a polystyrene resin, a vinyl chloride resin, a polycarbonate resin or a polyester resin, by molding.




A thermal transfer recording method according to the present invention inserts the flanged shaft


411


in the bore


408


of the thermal transfer recording web roll


402


, and inserts the tubular part


425


of the flanged shaft


410


in the tubular part


426


of the flanged shaft


411


so that the inner end segment


419


of the thermal transfer recording web roll


402


is extended through the slits


418




a


and


418




b


of the flanged shafts


410


and


411


. Then, the flanged shafts


410


and


411


are turned in opposite directions, respectively, to hold the inner end segment


419


between the tubular parts


425


and


426


of the flanged shafts


410


and


411


, and then the flanged shaft


411


is turned in a winding direction to wind the thermal transfer recording web roll


402


tight. Consequently, the thermal transfer recording web roll


402


is fastened firmly to the flanged shafts


410


and


411


. The flanged shafts


410


and


411


are driven for rotation through the gears


420


to rotate the thermal transfer recording web roll


402


for thermal transfer recording.




As apparent from the foregoing description, according to the present invention, the thermal transfer printer of the following construction enables the preparation of a thermal transfer recording web roll not requiring any feed core, at a low cost without requiring time and effort, and is capable of recording a thermal transfer image in a satisfactory image quality.




The respective tubular parts


425


and


426


of the flanged shafts


410


and


411


are inserted in the cenral bore of the thermal transfer recording web roll


402


formed by rolling a thermal transfer recording web


402




a


without using any core. The respective tubular parts


425


and


426


of the two flanged shafts


410


and


411


are provided with the slits


418




a


and


418




b


, respectively. The inner end segment


419


of the thermal transfer recording web


402




a


of the thermal transfer recording web roll


402


is passed through the slits


418




a


and


418




b


of the flanged shafts


410


and


411


, the flanged shafts


410


and


411


are turned in opposite directions, respectively, to hold the inner end segment


419


between the tubular parts


425


and


426


of the flanged shafts


410


and


411


, and then the flanged shaft


411


is turned in the winding direction to wind the thermal transfer recording web roll


402


tight. Thus, the thermal transfer recording web roll


402


and the flanged shaft


411


are fastened firmly together. The flanged shaft


11


is driven through the gear


420


to rotate the flanged shafts


410


and


411


together with the thermal transfer recording web roll


402


for thermal transfer recording.



Claims
  • 1. A thermal transfer recording web roll to be used for a thermal transfer printer with a pair of rotative driving members, having a bore, and formed by rolling a thermal transfer recording web;wherein (1) a segment of the thermal transfer recording web forming an innermost layer of the thermal transfer recording web roll is fixed to a part of a segment of the thermal transfer recording web forming a second innermost layer of the thermal transfer recording web roll; (2) the thermal transfer recording web roll is driven by the pair of rotative driving members and rotated in cooperation with the pair of rotative driving members; (3) the segment of the innermost layer of the thermal transfer recording web roll excluding an inner edge part is fixed to the second innermost layer of the thermal transfer recording web roll; and (4) the inner edge part of the thermal transfer recording web roll is so constructed that the inner edge part can be clamped by the rotative driving members.
Priority Claims (3)
Number Date Country Kind
2000-387164 Dec 2000 JP
2000-392445 Dec 2000 JP
2000-393069 Dec 2000 JP
Parent Case Info

This is a Continuation of application Ser. No. 10/022,221 filed Dec. 20, 2001.

Foreign Referenced Citations (3)
Number Date Country
6-1022 Jan 1994 JP
11-349197 Dec 1999 JP
2001-139192 May 2001 JP
Continuations (1)
Number Date Country
Parent 10/022221 Dec 2001 US
Child 10/347876 US