Plate-mounting member, for mounting and positioning flexible printing plate in plate clamping mechanism

Information

  • Patent Grant
  • 6736065
  • Patent Number
    6,736,065
  • Date Filed
    Wednesday, February 21, 2001
    23 years ago
  • Date Issued
    Tuesday, May 18, 2004
    20 years ago
Abstract
A plate-mounting member to be attached to a plate front end of a flexible plate in order to mount said flexible plate having a plurality of fixing holes onto a plate cylinder including a plate front end clamp mechanism having upper and lower teeth and at least two positioning pins disposed between upper and lower teeth, said plate-mounting member comprising a base and a plurality of fixing pins disposed on said base to be respectively inserted into said plurality of fixing holes formed in said plate front end, wherein said base is to be attached to said positioning pins disposed in said plate front end clamp mechanism to thereby position said plate front end. Also disclosed are method and apparatus for mounting a flexible printing plate.
Description




FIELD OF THE INVENTION




The present invention relates to a plate-mounting member which is used to mount a plate onto a plate cylinder disposed in a printing apparatus or a plate-making apparatus. The present invention also relates to method and apparatus for mounting a printing plate, especially, a digitally made flexible printing plate, onto a plate cylinder of a printing apparatus.




DESCRIPTION OF THE RELATED ART




In a lithographic printing apparatus, generally, a printing plate is wound around and fixed to a plate cylinder and, in this state, printing is executed.




However, a lithographic printing plate (in the present specification, this is referred to as a flexible printing plate), which uses as a support member a member formed of other material than metal inexpensive and easy to handle (for example, a plastic film or paper), has a weak point in dimensional stability. For example, the flexible printing plate can be deformed depending on the way of handling of the flexible printing plate when it is mounted or due to a frictional force between a rubber cylinder and itself during printing, which can degrade the printing dimension as well as the printing position accuracy with respect to paper.




Therefore, use of the flexible printing plate of the above type, conventionally, is limited to a simple printing which prints a relatively small number of printings and does not require the high matching accuracy of the printings; that is, such flexible printing plate has not been employed in a high-quality printing using multiple colors and requiring great delicacy or in a full-dress printing using a large-scale printing machine.




Here, description will be given in detail of the above-mentioned deformation that is caused depending on the way of handling of the flexible printing plate when it is mounted. In

FIGS. 19 and 20

, there is shown a typical printing plate-mounting apparatus. Specifically,

FIG. 20

is a view of the printing plate-mounting apparatus when it is viewed from the direction of the arrow mark X shown in

FIG. 19

; and,

FIG. 19

is a section view taken along the line Y—Y shown in FIG.


20


.




As shown in

FIG. 19

, the plate cylinder


61


of the printing machine is structured such that a portion of a cylinder is cut away along the axial direction of the cylinder and, in a substantially flat surface (which is hereinafter referred to as a flat surface portion


61




a,


which is the cut face of the cutaway portion of the cylinder), there is formed a groove portion


65


. And, within the groove portion


65


, there are disposed a plate front end clamp mechanism


62


for holding the front end or leading end of a printing plate


70


, and a plate rear end clamp mechanism


63


for holding the rear end or trailing end of the printing plate


70


. The clamp mechanisms


62


and


63


respectively include lower teeth


62




b


and


63




b


(the upper surfaces of which are substantially flush with the flat surface portions


61




a


), and upper teeth


62




a


and


63




a


which are rotatably supported by their respective lower teeth and are capable of holding the plate front end or rear end between the upper surfaces of their respective lower teeth and themselves. Further, there is disposed a position adjusting mechanism (not shown) which is capable of adjusting the positions of the plate front end clamp mechanism


62


and plate rear end clamp mechanism


63


in the back-and-forth direction, in the right-and-left direction and in the oblique direction on the bottom surface of the groove portion


65


.




Between the two flat surface portions


61




a


and curved surface portion


61




b


of the plate cylinder


61


, there are formed top portions


61




c


respectively. Although not shown, there is known another type of plate cylinder in which there are formed top portions between the upper surfaces of the lower teeth of the clamp mechanisms, instead of the flat surface portions, and the curved portion of the plate cylinder.




Normally, the portions of the plate cylinder


61


, where the two flat surface portions


61




a


and curved surface portion


61




b


cross each other, are each rounded to thereby provide a curved surface having a radius of 5-30 mm. It should be noted here that, in the present specification, such curved surface portions are also referred to as top portions.




And, as shown in

FIG. 20

, two positioning pins


64


are respectively provided on and projected from the upper surface of the lower tooth


62




b


of the plate front end clamp mechanism; specifically, at two positions of the lower tooth


62




b


upper surface which are spaced from each other in the axial direction of the plate cylinder


61


. At the positions of the upper surface


62


of the plate front end clamp mechanism that correspond to the positioning pins


64


, there are formed notches


66


respectively. Also, in the front end portion


70




a


of the printing plate


70


which is shown by a two-dot chained line in

FIG. 20

; specifically, at the positions of the front end portion


70




a


that correspond to the positioning pins


64


, there are also formed two notches


71


respectively.




Recently, as printings have been turned into small lots and diversified, there has increased the need for a plate (which, in the present specification, is referred to as a flexible plate comprising a support member formed of material which is inexpensive and easy to handle (for example, plastic film, paper) other than metal, and a photosensitive layer disposed on such support member. However, since such plate is high in flexibility, there arise several problems when it is mounted on the plate cylinder.




For example, there is generally known a case where the flexible printing plate


70


is mounted onto the plate cylinder


61


using the printing plate-mounting apparatus shown in

FIGS. 7 and 8

. Specifically, in this case, when, while holding the plate rear end


70




b,


an operator pushes the plate front end


70




a


of the printing plate between the upper tooth


62




a


and lower tooth


62




b


of the plate front end clamp mechanism to thereby bring the plate front end


70




a


into contact with two positioning pins


64


, there is a fear that the plate front end


70




a


can be deformed and can be fixed in such deformed state. That is, in a plate cylinder capable of mounting thereon a printing plate of a half-kiku size or more, the distance between the two positioning pins


64


in the plate cylinder


61


is fairly wide; and, therefore, when mounting the printing plate


70


onto the plate cylinder


61


, in case where the operator overpushes the printing plate


70


even slightly, the printing plate


70


can be deformed in such a manner that the plate front end


70




a


is projected in the pushing direction from between the two positioning pins


64


. However, in case where the operator pushes the printing plate


70


insufficiently in order to avoid such deformation of the printing plate


70


, the printing plate


70


cannot be positioned accurately.




As described above, the mountability of the flexible plate onto the plate cylinder is poor and thus it is difficult to always mount the flexible plate onto the plate cylinder in a constant state. Therefore, there are necessary a plurality of plate cylinders and thus, in case where the flexible plate is used in a multicolor printing (for example, four-color printing) which requires strict matching between the plate cylinders, mismatching can occur.




Also, as shown in

FIG. 19

, in the vicinity of the top portions


61




c


respectively formed between the flat surface portions


61




a


and curved portion


61




b


of the plate cylinder


61


, the flexible printing plate


70


does not easily stick to the outer peripheral surface of the plate cylinder


61


but the flexible printing plate


70


tends to float up from the outer peripheral surface of the plate cylinder


61


.




In order to prevent such flotation of the printing plate


70


, an operator, while pulling strongly the plate rear end of the printing plate


70


with the plate front end thereof held by the plate front end clamp mechanism


62


, rotates the plate cylinder to thereby wind the printing plate


70


onto the plate cylinder. In this case, however, the strongly pulled portion of the plate rear end of the flexible printing plate


70


is stretched loosely.




After the printing plate is wound onto the plate cylinder while pulling the plate rear end in the above-mentioned manner, the plate rear end of the printing plate is pushed into between the upper and lower teeth of the plate rear end clamp mechanism, the upper tooth is rotated to thereby fix the plate rear end, and, using a tension apply mechanism (not shown), the plate rear end clamp mechanism is moved in a direction where a tensile force is applied to the printing plate, thereby bringing the printing plate into close contact with the peripheral surface of the plate cylinder, which completes the mounting of the printing plate onto the plate cylinder.




However, in an ordinary conventional plate-mounting apparatus, the tension apply mechanism for contacting the flexible printing plate with the peripheral surface of the plate cylinder closely is designed in combination with a printing plate having a support member formed of metal such as aluminum; and, therefore, in the case of the flexible printing plate, it is stretched more than necessary.




Also, in case where the tension apply mechanism is designed such that it can apply a lower tensile force according to the flexible printing plate, the tensile force applied is too weak to closely contact the printing plate with the plate cylinder. Even if the printing plate can be mounted onto the plate cylinder in such a manner that the printing plate is prevented from floating up from the plate cylinder, in the case of such weak tensile force, the printing plate deviates in position due to a frictional force which is produced between a rubber cylinder and itself in printing.




Recently, in a lithographic printing method, due to the enhancement in the latest digital picture drawing technology as well as due to the need for enhancement in the efficiency of processing, there have been proposed a large number of systems for drawing digital image information directly on a printing plate. This is a technology which is referred to as CTP (Computer-to-plate) or DDPP (Digital Direct Printing Plate).




This technology is advantageous over a conventional plate making method (which provides close-contact exposure with a lith film superimposed on top of a printing plate) in that it can provide better image position accuracy with respect to a flexible printing plate and better matching accuracy in a multicolor printing.




Of course, there is also proposed a digital reprographic (plate making) system using a flexible printing plate; and, because it is inexpensive, there exists the need for a multicolor printing using this system. However, since the flexible printing plate has the above-mentioned problems, it cannot make the best use of its advantage that it can provide excellent image position accuracy in the digital reprography; and, therefore, in a multicolor printing, it has not been able to realize matching accuracy equivalent to that of the printing plate having a metal support member.




SUMMARY OF THE INVENTION




The present invention aims at eliminating the above-mentioned drawbacks.




Accordingly, an object of the invention is to provide a flexible plate-mounting member which is capable of mounting a flexible plate onto a plate cylinder positively and easily.




Another object of the invention to provide flexible printing plate-mounting method and apparatus which is capable of mounting a digitally-made flexible printing plate easily without deforming the same, allows the flexible printing plate to be applied to a conventional printing machine with slight improvements, and allows the flexible printing plate to provide dimensional stability equivalent to that of a metal support member printing plate as well as matching accuracy in a multicolor printing.




Other objects and effects of the present invention will become apparent from the following description.




In a first aspect, the present invention relates to the following items (1-1) to (1-3).




(1-1) A plate-mounting member to be attached to a plate front end of a flexible plate in order to mount said flexible plate having a plurality of fixing holes onto a plate cylinder including a plate front end clamp mechanism having upper and lower teeth and at least two positioning pins disposed between upper and lower teeth, said plate-mounting member comprising a base and a plurality of fixing pins disposed on said base to be respectively inserted into said plurality of fixing holes formed in said plate front end, wherein said base is to be attached to said positioning pins disposed in said plate front end clamp mechanism to thereby position said plate front end.




(1-2) The plate-mounting member according to item (1-1) above, wherein said plurality of fixing pins are disposed on said base along the width direction of said plate and the distance between adjacent fixing pins is not more than 400 mm.




(1-3) The plate-mounting member according to item (1-1) or (1-2) above, wherein deformation preventive notches are formed in the portions of said base that are to be held by said upper and lower teeth.




In a second aspect, the present invention relates to the following items (2-1) to (2-13).




(2-1) A flexible printing plate-mounting method for mounting a flexible printing plate having three or more notches formed in a plate front end thereof onto a plate cylinder, comprising the steps of:




providing a flexible printing plate-mounting apparatus comprising:




a plate front end positioning and fixing mechanism comprising: a plate front end clamp mechanism having upper teeth and lower teeth for fixing the plate front end of said printing plate to said plate cylinder; and at least three positioning pins respectively disposed in said plate front end clamp mechanism in such a manner that they are respectively opposed to said notches of said printing plate;




a printing plate pressure mechanism for pressing said printing plate against said plate cylinder;




a plate rear end fixing mechanism for fixing the plate rear end of said printing plate to said plate cylinder; and




a packing sheet which is wound and fixed to said plate cylinder and has a function of preventing positional deviation of said printing plate;




positioning and fixing said plate front end to said plate cylinder by inserting the plate front end of said printing plate into between said upper and lower teeth of said plate front end clamp mechanism to contact the inner peripheral surfaces of said notches of said plate front end with said at least three positioning pins;




winding said printing plate onto said plate cylinder by rotating said plate cylinder with said plate rear end set free, while said printing plate pressure mechanism presses said printing plate against the entire outer peripheral surface of said plate cylinder including top portions thereof using a pressure member; and




pressing and fixing said plate rear end of said printing plate in a radial direction of said plate cylinder using said plate rear end fixing mechanism after completion of said winding;




whereby stretching of said flexible printing plate in its maximum printing length in the rotational direction of said plate cylinder during said printing plate-mounting operation is suppressed to 100 μm or less.




(2-2) A flexible printing plate-mounting method for mounting a flexible printing plate having at least three fixing holes formed in a plate front end thereof onto a plate cylinder, comprising the steps of:




providing a flexible printing plate-mounting apparatus comprising:




a plate front end positioning and fixing mechanism comprising: a plate front end clamp mechanism having upper teeth and lower teeth for fixing the plate front end of said printing plate to said plate cylinder; positioning pins disposed in said plate front end clamp mechanism; and a pin contact member which has higher rigidity than said printing plate, is to be attached to said positioning pin and has at least three fixing pins for fixing said printing plate;




a printing plate pressure mechanism for pressing said printing plate against said plate cylinder;




a plate rear end fixing mechanism for fixing the plate rear end of said printing plate to said plate cylinder; and




a packing sheet which is wound and fixed to said plate cylinder and has a function of preventing positional deviation of said printing plate;




positioning and fixing said plate front end to said plate cylinder by allowing said fixing holes of said printing plate to be inserted with said fixing pins of said pin contact member between said upper and lower teeth of said plate front end clamp mechanism;




winding said printing plate onto said plate cylinder by rotating said plate cylinder with said plate rear end set free, while said printing plate pressure mechanism presses said printing plate against the entire outer peripheral surface of said plate cylinder including top portions thereof using a pressure member; and




pressing and fixing said plate rear end of said printing plate in a radial direction of said plate cylinder using said plate rear end fixing mechanism after completion of said winding;




whereby stretching of said flexible printing plate in its maximum printing length in the rotational direction of said plate cylinder during said printing plate-mounting operation is suppressed to 100 μm or less.




(2-3) A flexible printing plate-mounting method for mounting a flexible printing plate having at least three fixing holes formed in a plate front end thereof onto a plate cylinder, comprising the steps of:




providing a flexible printing plate-mounting apparatus comprising:




a plate front end positioning and fixing mechanism comprising: a plate front end clamp mechanism having upper teeth and lower teeth for fixing the plate front end of said printing plate to said plate cylinder; and a positioning pin disposed in said plate front end clamp mechanism;




a printing plate pressure mechanism for pressing said printing plate against said plate cylinder;




a plate rear end fixing mechanism for fixing the plate rear end of said printing plate to said plate cylinder;




a packing sheet which is wound and fixed to said plate cylinder and has a function of preventing positional deviation of said printing plate; and




a pin contact member which has higher rigidity than said printing plate and includes at least three fixing pins for fixing said printing plate;




fixing said printing plate on said pin contact member by allowing said fixing holes of said printing plate to be inserted into said fixing pins of said pin contact members respectively;




fixing and positioning said printing plate onto said plate cylinder by fixing a leading end of said pin contact member to said positioning pin between said upper and lower teeth of said plate front end clamp mechanism;




winding said printing plate onto said plate cylinder by rotating said plate cylinder with said plate rear end set free, while said printing plate pressure mechanism presses said printing plate against the entire outer peripheral surface of said plate cylinder including top portions thereof using a pressure member; and




pressing and fixing said plate rear end of said printing plate in a radial direction of said plate cylinder using said plate rear end fixing mechanism after completion of said winding;




whereby stretching of said flexible printing plate in, its maximum printing length in the rotational direction of said plate cylinder during said printing plate-mounting operation is suppressed to 100 μm or less.




(2-4) The flexible printing plate-mounting method according to any one of items (2-1) to (2-3) above, wherein said packing sheet has at least one roughened surface, and said packing sheet is wound and fixed onto said plate cylinder in such a manner that said roughened surface side becomes an outer surface side.




(2-5) The flexible printing plate-mounting method according to any one of items (2-1) to (2-3) above, wherein said packing sheet has at least one sticky surface, and said packing sheet is wound and fixed onto said plate cylinder in such a manner that said sticky surface side becomes an outer surface side.




(2-6) The flexible printing plate-mounting method according to any one of items (2-1) to (2-5) above, wherein said flexible printing plate-mounting apparatus further comprises a guide member for holding said printing plate, wherein said guide member holds said printing plate, before and during mounting said printing plate onto said plate cylinder, in such a manner that the plate rear end thereof is set free.




(2-7) A flexible printing plate-mounting apparatus for mounting a flexible printing plate having three or more notches formed in a plate front end thereof onto a plate cylinder, said flexible printing plate-mounting apparatus comprising:




a plate front end positioning and fixing mechanism comprising: a plate front end clamp mechanism having upper teeth and lower teeth for fixing the plate front end of said printing plate to said plate cylinder; and at least three positioning pins respectively disposed in said plate front end clamp mechanism in such a manner that they are respectively opposed to said notches of said printing plate;




a printing plate pressure mechanism for pressing said printing plate against said plate cylinder;




a plate rear end fixing mechanism for fixing the plate rear end of said printing plate to said plate cylinder; and




a packing sheet which is wound and fixed to said plate cylinder and has a function of preventing positional deviation of said printing plate.




(2-8) A flexible printing plate-mounting apparatus for mounting a flexible printing plate onto a plate cylinder, said flexible printing plate-mounting apparatus comprising:




a plate front end positioning and fixing mechanism comprising: a plate front end clamp mechanism having upper teeth and lower teeth for fixing the plate front end of said printing plate to said plate cylinder; positioning pins disposed in said plate front end clamp mechanism; and a pin contact member which has higher rigidity than said printing plate, is to be attached to said positioning pin and has at least three fixing pins for fixing said printing plate;




a printing plate pressure mechanism for pressing said printing plate against said plate cylinder;




a plate rear end fixing mechanism for fixing the plate rear end of said printing plate to said plate cylinder; and




a packing sheet which is wound and fixed to said plate cylinder and has a function of preventing positional deviation of said printing plate.




(2-9) A flexible printing plate-mounting apparatus for mounting a flexible printing plate onto a plate cylinder, said flexible printing plate-mounting apparatus comprising:




a plate front end positioning and fixing mechanism comprising: a plate front end clamp mechanism having upper teeth and lower teeth for fixing the plate front end of said printing plate to said plate cylinder; and a positioning pin disposed in said plate front end clamp mechanism;




a printing plate pressure mechanism for pressing said printing plate against said plate cylinder;




a plate rear end fixing mechanism for fixing the plate rear end of said printing plate to said plate cylinder;




a packing sheet which is wound and fixed to said plate cylinder and has a function of preventing positional deviation of said printing plate; and




a pin contact member which has higher rigidity than said printing plate and includes at least three fixing pins for fixing said printing plate.




(2-10) The flexible printing plate-mounting apparatus according to any one of items (2-7) to (2-9) above, wherein said packing sheet has at least one roughened surface, and said packing sheet is wound and fixed onto said plate cylinder in such a manner that said roughened surface side becomes an outer surface side.




(2-11) The flexible printing plate-mounting apparatus according to any one of items (2-7) to (2-9) above, wherein said packing sheet has at least one sticky surface, and said packing sheet is wound and fixed onto said plate cylinder in such a manner that said sticky surface side becomes an outer surface side.




(2-12) The flexible printing plate-mounting apparatus according to any one of items (2-7) to (2-11), further comprising a guide member for holding said printing plate, before and during mounting said printing plate onto said plate cylinder, in such a manner that the plate rear end thereof is set free.




(2-13) The flexible printing plate-mounting apparatus according to any one of items (2-7) to (2-12), further comprising:




a rotating member for rotating said plate cylinder when mounting said printing plate onto said plate cylinder;




a detector for detecting the rotational position of said plate cylinder;




a rotation controller for controlling the rotation and stopping of said plate cylinder rotating member at given positions in accordance with signals from said rotational position detector;




a driving member for driving said pressure member so as to be into contact with or separated from said plate cylinder; and




a controller for controlling said driving member at given positions in accordance with signals from said rotational position detector.











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

is a schematic view of embodiment 2-1 of the flexible printing plate-mounting apparatus according to the invention;





FIG. 2

is a view taken from the direction of the arrow mark X shown in

FIG. 1

;





FIG. 3

is a view of a plate base material wound around a plate cylinder according to embodiment 2-1;





FIG. 4

is a view of a hold roller employed in embodiment 2-1;





FIG. 5

shows how to mount a flexible printing plate according to embodiment 2-1;





FIG. 6

also shows how to mount a flexible printing plate according to embodiment 2-1;





FIG. 7

also shows how to mount a flexible printing plate according to embodiment 2-1;





FIG. 8

also shows how to mount a flexible printing plate according to embodiment 2-1;





FIG. 9

is a view of a flexible printing plate and a pin contact member employed in embodiment 2-2 of the flexible printing plate-mounting apparatus according to the invention;




FIGS.


10


(A) and


10


(B) is a view of the flexible printing plate and pin contact member shown in

FIG. 9

, showing a state in which the pin contact member is fixed to the flexible printing plate;





FIG. 11

is a view of a flexible printing plate and a pin contact member employed in embodiment 2-3 of the flexible printing plate-mounting apparatus according to the invention;





FIG. 12

is a view of the flexible printing plate and pin contact member shown in

FIG. 11

, showing a state in which the pin contact member is fixed to the flexible printing plate;





FIG. 13

is a view of embodiment 2-4 of the flexible printing plate-mounting apparatus according to the invention;





FIG. 14

is a view of embodiment 2-5 of the flexible printing plate-mounting apparatus according to the invention;





FIG. 15

is a partially enlarged view of a plate cylinder used in embodiment 2-6 of the flexible printing plate-mounting apparatus according to the invention;





FIG. 16

is a section view taken along the line Y—Y shown in

FIG. 15

;





FIG. 17

is a partially enlarged view of a plate cylinder used in embodiment 2-7 of the flexible printing plate-mounting apparatus according to the invention;





FIG. 18

is a section view taken along the line Y—Y shown in

FIG. 17

;





FIG. 19

is a view of a conventional flexible printing plate-mounting apparatus; and,





FIG. 20

is a view taken from the direction of the arrow mark X shown in FIG.


19


.





FIG. 21

is a plan view of embodiment 1-1 of the plate-mounting member according to the invention;





FIG. 22

is an enlarged view of the main portions of embodiment 1-1 shown in

FIG. 21

;





FIG. 23

is a section view taken along the line III—III shown in

FIG. 22

;





FIG. 24

is a plan view of embodiment 1-2 of the plate-mounting member according to the invention;





FIG. 25

is an enlarged view of the main portions of embodiment 1-2 shown in

FIG. 24

;





FIG. 26

is a plan view of embodiment 1-3 of the plate-mounting member according to the invention;











DETAILED DESCRIPTION OF THE INVENTION




The first aspect of the present invention is described in more detail below.




As the flexible plate, there can be used a support member which is formed of a plastic film or paper other than metal, and a support member which is a combination of such plastic film and paper support members. In more detail, there can be used a support member comprising a plastic film which is formed of polyester, polyethylene terephthalate, polyethylene naphthalate, or polycarbonate; and, a support member comprising a composite sheet which can be produced in such a manner that a plastic sheet formed of polyethylene or polypropylene is laminated on paper. Although it is suitable that the thickness of the support member is set in the range of 75-500 μm, the optimum value of the support member thickness varies according to the kinds of the support members used and printing conditions. Generally, most preferably, the thickness of the support member may be set in the range of 100-400 μm.




The positioning pin disposed in the plate front end clamp mechanism includes a pin which is provided on and projected from the upper surface of the lower tooth of the plate front end clamp mechanism toward the upper tooth thereof, a pin which is provided on and projected from the lower surface of the upper tooth of the plate front end clamp mechanism toward the lower tooth thereof, and a pin which is provided on and projected from the plate cylinder and is arranged in the vicinity of the plate front end clamp mechanism.




The material of the base of the plate-mounting member, preferably, may be higher in rigidity than the flexible plate; for example, metal can be used. The fixing pin may be a pin which is formed integral with the base, or a pin which is produced separately and mounted onto the base afterward.




By using the above-structured plate-mounting member, the front end of the flexible plate can be protected by the plate-mounting member to thereby eliminate the possibility that the plate front end can be projected from between the two positioning pins. Therefore, the mountability of the flexible plate onto the plate cylinder can be enhanced remarkably. This not only can reduce the burden of the operator but also can prevent the above-mentioned mismatching to thereby allow the flexible plate to be used in a multicolor printing as well.




Also, in the above structure, in case where the plurality of fixing pins are disposed on the base of the plate-mounting member along the width direction of the plate and the distance between the fixing pins is equal to or less than 400 mm, the plate can be prevented from being deformed in such a manner that the plate front end is projected from between the two positioning pins. More preferably, in case where the distance between the fixing pins is equal to or less than 270 mm, the plate can be prevented against deformation more positively. The distance between the fixing pins may not be constant, provided it exists in the above-mentioned range.




Also, in case where deformation preventive notches are respectively formed at the positions of the base which are held by the upper and lower teeth, the durability of the plate-mounting member can be enhanced.




Now, description will be given below in detail of preferred embodiments of the plate-mounting member according to the first aspect of the invention with reference to the accompanying drawings. The parts that have been previously described herein are given the same designations or corresponding designations in the drawings and thus the description thereof is simplified or omitted here.




In

FIG. 21

, there are shown a plate-mounting member


30


which provides embodiment 1-1 according to the invention, and a polyester-made printing plate


80


used as a flexible plate onto which the plate-mounting member


30


is to be mounted.




In the plate front end


80




a


of the printing plate


80


, more specifically, at the two portions of the plate front end


80




a


that respectively correspond to the two positioning pins


64


shown in

FIG. 20

, there are formed two notches


81


each having a substantially U-shaped peripheral edge. Also, in the plate front end


80




a,


there are opened up a plurality of (in this embodiment, 7) fixing holes


82


which are spaced from one another by a given distance W


1


in the width direction of the printing plate


80


(the direction along the axial direction of the plate cylinder; in

FIG. 21

, in the right and left direction). The fixing holes


82


can be formed at the same time when the notches


81


are formed.




The plate-mounting member


30


is made of steel, stainless steel, other alloy steel, or brass. The plate-mounting member


30


includes a band-shaped (a rectangular-shaped) base


31


having a length equal to or greater than the width of the printing plate


80


. In the portions of the base


31


that respectively correspond to the two positioning pins


64


, there are formed circular-shaped insertion holes


33


. Also, on the base


31


, there are projectingly provided a plurality of (in this embodiment, 7) fixing pins


32


which are spaced from one another by a given distance in the longitudinal direction of the base


31


. The plurality of fixing pins


32


are disposed on a straight line extending along the width direction of the printing plate


80


, that is, along the longitudinal direction of the plate-mounting member


30


. The size of the fixing pin


32


is not limited but, for example, the fixing pin


32


can be set such that it has a diameter of 6 mm and a height of 4 mm or so. The transverse-direction width of the base


31


is also not limited but the width may only be set such that the base


31


can be prevented from touching the top portions of the plate cylinder when it is mounted onto the plate cylinder.




Now,

FIG. 22

shows an enlarged view of the neighboring portion of each notch


81


of the printing plate


80


shown in

FIG. 21

when the plate-mounting member


30


is mounted onto the plate front end


80




a


of the printing plate


80


. As shown in

FIG. 22

, by inserting the fixing pin


32


of the plate-mounting member


30


into the fixing hole


82


of the printing plate


80


, the plate-mounting member


30


can be fixed to the printing plate


80


. Here, the plate-mounting member


30


and printing plate


80


are set such that a portion of the peripheral edge of the circular-shaped insertion hole


33


of the plate-mounting member


30


can be matched to the curved portion of the substantially U-shaped peripheral edge of the notch


81


of the printing plate


80


.




When mounting the printing plate


80


onto the plate cylinder


61


shown in

FIG. 20

, with the insertion holes


33


of the plate-mounting member


30


respectively inserted into their associated positioning pins


64


of the plate front end clamp mechanism


62


, the plate front end


80




a


of the printing plate


80


is fixed to the plate-mounting member


30


.




Now,

FIG. 23

is a section view taken along the line III—III shown in FIG.


22


. As shown by a two-dot chained line in

FIG. 23

, when the positioning pins


64


of the plate cylinder


61


are inserted into the insertion holes of the plate-mounting member


30


, the inner peripheral surface of the notches


81


of the printing plate


80


are contacted with the positioning pins


64


together with the inner peripheral surfaces of the insertion holes


33


of the plate-mounting member


30


.




With use of the above-structured plate-mounting member


30


, the plate front end


80




a


of the printing plate


80


can be protected by the plate-mounting member


30


as well as the printing plate


80


can be prevented from being deformed in such a manner that the plate front end


80




a


thereof is projected from between the two positioning pins


64


. Therefore, not only the mountability of the flexible printing plate


80


onto the plate cylinder can be enhanced remarkably to thereby reduce the burden of the operator, but also the above-mentioned mismatching can be prevented to thereby allow the flexible printing plate


80


to be used in a multicolor printing as well.




Since a conventionally used plate cylinder can be used as it is, the facility cost cannot be expensive.




Now,

FIG. 24

shows a plate-mounting member


40


, which provides embodiment 1-2 according to the invention, and a printing plate


80


. The plate-mounting member


40


includes a base


41


having a length equal to or greater than the width of the printing plate


80


. In the portions of the base


41


that respectively correspond to the two positioning pins


64


of the plate cylinder


61


shown in

FIG. 20

, there are formed two notches


43


each having a substantially U-shaped peripheral edge. Also, on the base


41


, there are projectingly provided a plurality of (in this embodiment, 7) fixing pins


42


in such a manner that they are spaced from one another by a given distance W


2


(in this embodiment, 120 mm) in the longitudinal direction of the base


41


.




Now,

FIG. 25

shows an enlarged view of the neighboring portion of each notch


81


of the printing plate


80


when the plate-mounting member


40


is mounted onto the plate front end


80




a


of the printing plate


80


shown in FIG.


24


. As shown in

FIG. 25

, by inserting the fixing pins


42


of the plate-mounting member


40


into their associated fixing holes


82


of the printing plate


80


, the plate-mounting member


40


can be fixed to the printing plate


80


. Here, the plate-mounting member


40


and printing plate


80


are set such that the peripheral edges of the notches


43


of the plate-mounting member


40


can be matched to the peripheral edges of the notches


81


of the printing plate


80


.




With use of the above-structured plate-mounting member


40


, not only the plate front end


80




a


of the flexible printing plate


80


can be protected by the plate-mounting member


40


but also the printing plate


80


can be prevented from being deformed in such a manner that the plate front end


80




a


thereof is projected from between the two positioning pins


64


.




Also, according to the present plate-mounting member


40


, when the plate front end


80




a


of the printing plate


80


is fixed to the plate front end clamp mechanism after the plate-mounting member


40


is fixed to the plate front end


80




a,


the plate-mounting member


40


can be inserted into between the upper and lower teeth of the plate front end clamp mechanism, which makes it possible to further simplify the positioning operation of the plate front end


80




a.






Now,

FIG. 26

shows a plate-mounting member


50


, which provides embodiment 1-3 according to the invention, and a printing plate


80


. The plate-mounting member


50


includes a base


51


having a length equal to or greater than the width of the printing plate


80


. In the portions of the base


51


that respectively correspond to the two positioning pins


64


of the plate cylinder


61


shown in

FIG. 20

, there are formed circular-shaped insertion holes


53


. Also, on the base


51


, there are projectingly provided a plurality of (in this embodiment, 7) fixing pins


52


in such a manner that they are spaced from one another by a given distance in the longitudinal direction of the base


51


. Further, in the long side of the base


51


which is opposite to the side thereof where the fixing pins


52


are projectingly provided, more specifically, in the portions of such long side that are to be held by the upper and lower teeth of the plate front end clamp mechanism, there are formed a plurality of (in this embodiment, 6) deformation preventive notches


54


at regular intervals. In this embodiment, each of the deformation preventive notches


54


is formed in a trapezoidal shape when it is viewed from above.




In the above-structured plate-mounting member


50


, when the base


51


is held by and between the upper and lower teeth of the plate front end clamp mechanism, even in case where the base


51


is thereby crushed, the deformation preventive notches


54


are appropriately deformed in shape so as to be able to prevent the whole of the plate-mounting member


50


from being deformed. That is, the deformation of the whole of the plate-mounting member


50


can be absorbed by the deformation of the deformation preventive notches


54


. Therefore, the durability of the plate-mounting member


50


can be enhanced.




As has been described in detail heretofore, with use of the plate-mounting member according to the first aspect of the invention, not only the mountability of the flexible plate onto the plate cylinder can be enhanced remarkably to thereby reduce the burden of the operator, but also the above-mentioned mismatching can be prevented to thereby allow the flexible plate to be used in a multicolor printing as well.




Next, the second aspect of the present invention is described in more detail below.




The term “the maximum printing length in the plate cylinder rotation direction during the printing plate-mounting operation” means the maximum length that can be printed on paper; and, in the specification and instruction manual of a printing machine, as such maximum printing length, there is set forth a concrete numeric value. Generally, this length can be regarded as the length of the area of the plate cylinder on the diameter circumference thereof that extends from the neighboring portion of the top portion of the plate front end to the neighboring portion of the top portion of the plate rear end.




As the pressure member, there can be employed a roller-shaped pressure member which can be driven by a driving member so as to be contacted with or separated from the plate cylinder. Also, there may also be used a flat-surface pressure member such as a pad-shaped, brush-shaped, or flat-surface-shaped pressure member, which can be driven by a driving member so as to be contacted with or separated from the plate cylinder.




As the positioning pin, there can be employed a pin which is provided on and projected from the upper surface of the lower tooth of the plate front end clamp mechanism toward the upper tooth of the plate front end clamp mechanism, a pin which is provided on and projected from the lower surface of the upper surface toward the lower tooth, or a pin which is provided integrally with the plate cylinder.




As the plate rear end fixing mechanism, there can be used a plate rear end clamp mechanism which includes an upper tooth and a lower tooth. Also, there can also be employed a plate rear end hold mechanism using a plate-spring-shaped member, or means for attaching the plate rear end to the plate cylinder surface or a plate rear end clamp member using a double adhesive tape or spray glue.




According to the above-described items (2-1) and (2-7) of the invention, since the flexible printing plate is contacted with three or more positioning pins and is thereby positioned, the distance between the positioning pins in the plate cylinder is narrow, which can eliminate the possibility that the printing plate can be deformed in such a manner that the plate front end can be projected from between the positioning pins. Also, when winding the printing plate onto the plate cylinder, the pressure member presses the printing plate against the entire outer peripheral surface of the plate cylinder including the top portions thereof to thereby bring the printing plate into close contact with the plate cylinder outer peripheral surface. This eliminates the need to wind the printing plate onto the plate cylinder while pulling the plate rear end thereof; that is, a tensile force is not applied to the printing plate positively, so that the printing plate is little stretched. Therefore, even when the stretching of the printing plate due to the resistance of the pressure member in the printing plate-mounting operation is taken into consideration, the stretching of the printing plate in the maximum printing length can be controlled down to 100 μm or less.




Further, since the packing sheet, which is capable of preventing the printing plate from deviating in position after it is wound around and fixed to the plate cylinder, supports the wound printing plate strongly, normally, in case where the tensile force of the printing plate is zero or small, the printing plate can be prevented from deviating in position due to a frictional force produced between the printing plate and rubber cylinder during printing.




Therefore, the dimensional stability of the printing plate in the printing plate-mounting operation as well as in the printing operation can be enhanced remarkably, which makes it possible to obtain multicolor printing matching accuracy equivalent to that of a metal support member printing plate. Further, the mountability of the flexible printing plate onto the plate cylinder can be enhanced greatly, so that the burden of the operator can be relieved.




Needless to say, in the conventional plate-mounting method, it is impossible to realize the subject matter of the present invention that the stretching of the printing plate in the maximum printing length in the plate cylinder rotation direction in the flexible printing plate-mounting operation can be controlled down to 100 μm or less. The first reason for this is that, as described above, when winding the printing plate onto the plate cylinder by rotating the plate cylinder while pulling the plate rear end of the printing plate strongly in order to prevent the printing plate from being floated up from the plate cylinder, the printing plate is easily stretched 100 μm or more. The second reason is that, since the above-mentioned tensile force apply mechanism is designed according to the printing plate using a support member formed of metal such as aluminum, in the case of the flexible printing plate, it is easily stretched 100 μm or more. Also, in case where the tensile force apply mechanism is so designed according to the flexible printing plate as to apply such a low tensile force that can control the stretching of the printing plate down to 100 μm or less, the printing plate cannot be closely contacted with the plate cylinder due to shortage of the tensile force. Even in case where the printing plate can be mounted onto the plate cylinder in such a manner that it is prevented from being floated up from the plate cylinder, with such low tensile force, the printing plate can deviate in position due to a frictional force produced between the rubber cylinder and printing plate in the printing operation.




To control the stretching of the printing plate in the maximum printing length in the plate cylinder rotation direction in the flexible printing plate-mounting operation down to 100 μm or less, in the case of the flexible printing plate, can be attained regardless of the material, size (length, width, thickness) of the flexible printing plate. This is because the flexible printing plate-mounting method according to the invention is a mounting method which does not apply a tensile force to the flexible printing plate positively.




According to the structures employed in the above-described items (2-2), (2-3), (2-8) and (2-9) of the invention, the plate front end of the printing plate can be protected by the high-rigidity pin contact member including at least three fixing pins and thus the deformation of the plate front end can be prevented. Therefore, without increasing the number of positioning pins used, these structures can be relatively easily applied to an existing printing apparatus and an existing plate making apparatus as well. As the material of the pin contact member having higher rigidity than the printing plate, there can be selected metal. However, the material of the pin contact member is not limited to metal specifically.




According to the structures employed in the above-described items (2-4), (2-5), (2-10) and (2-11) of the invention, the plate base material supports the printing plate wound on the plate base material with a high frictional force or a high sticky force. This can eliminate the possibility that the printing plate can deviate in position due to a frictional force produced between the rubber cylinder and printing plate during printing after the printing plate is mounted onto the plate cylinder.




According to the structures employed in the above-described items (2-6) and (2-12) of the invention, by setting the printing plate in the guide member, there can be avoided the possibility that the flexible printing plate can hang down from the plate cylinder due to the low rigidity of the flexible printing plate. This eliminated the need to hold the printing plate by hand, which can in turn simplify the printing plate-mounting operation.




Also, due to the above, there is also eliminated the need to pull the plate rear end strongly, which can contribute effectively toward controlling the stretching of the printing plate.




According to the structure employed in the above-described item (2-13) of the invention, the operator need not execute the rotation and stopping of the plate cylinder as well as the contact and separation of the pressure member with respect to the plate cylinder which have been conventionally necessary when mounting the printing plate onto the plate cylinder. Therefore, not only the burden of the operator can be further relieved but also the flexible printing plate can be mounted onto the plate cylinder quickly.




In JP-A-10-24555 (The term “JP-A” as used herein means an “unexamined published Japanese patent application”), there are disclosed method and apparatus for positioning and fixing the plate front end of a flexible printing plate using three or more reference pins. The fixing method and apparatus employ a mechanism in which three or more reference pins are disposed on the upper surface of an upper tooth thereof and the reference pins are fitted into reference holes formed in a printing plate to thereby position and fix the printing plate. On the other hand, according to the invention, the reference pins are present between the upper and lower teeth of the plate front end clamp mechanism and are used for contact of the printing plate or pin contact member; and, the plate front end is fixed using the plate front end clamp mechanism. Therefore, the fixing method and apparatus disclosed in the above-cited publication are different from the invention in the structure of the apparatus as well as in the function of the reference pins. Also, in the above-cited publication, there is not disclosed the technological idea of the invention that the flexible printing plate is wound onto the plate cylinder while it is pressed against the entire outer peripheral surface of the plate cylinder using the pressure member.




Also, in the registered Japanese utility model publication 3014242, there is disclosed a flexible printing plate-mounting apparatus including a plate hold roller which is used to press a flexible printing plate against a plate cylinder. However, in this publication, there is not disclosed the technological idea of the invention that, in order to prevent the deformation of the plate front end of the flexible printing plate, the plate front end is contacted with three or more positioning pins, or, the plate front end of the printing plate is fixed to the pin contact member having higher rigidity than the printing plate and the pin contact member is then contacted with the positioning pins.




A plate rear end clamp mechanism employed in the printing plate-mounting apparatus disclosed in the above-cited registered utility model publication is structured such that it firstly holds the printing plate and, after then, it pulls the printing plate. That is, in this plate rear end clamp mechanism, there is not disclosed the technological idea of the invention that a tensile force is not applied to the printing plate positively.




Now, description will be given below in detail of preferred embodiments of the second aspect according to the invention with reference to the accompanying drawings. The parts thereof, which have been already discussed herein with reference to the conventional methods and apparatus, are given the same or corresponding designations and thus the description thereof is simplified or omitted here.





FIG. 1

shows embodiment 2-1 of the flexible printing plate-mounting apparatus according to the invention. Specifically,

FIG. 1

shows a flexible printing plate-mounting apparatus


10


which is used to mount a flexible (polyester-made) printing plate


70


onto a plate cylinder


11


provided in a printing apparatus for a multicolor printing (four-color printing).

FIG. 2

is a view of the apparatus


10


taken from the direction of the arrow mark X shown in

FIG. 1

, showing the plate cylinder


11


according to the present embodiment.




As shown in

FIG. 1

, the flexible printing plate-mounting apparatus


10


comprises a plate cylinder


11


including a plate front end clamp mechanism


12


and a plate rear end clamp mechanism


13


; a hold roller


17


and a rubber cylinder


25


which can be respectively contacted with and separated from the outer peripheral surface of the plate cylinder


11


; and, guide member


20


which is used to guide the plate front end of the flexible printing plate


70


to the plate front end clamp mechanism


12


. Here, the plate cylinder


11


can be rotated and stopped by a rotation controller (not shown). Also, the controller includes a member of detecting the rotational position of the plate cylinder


11


.




The guide member


20


is structured by disposing a guide roller


23


on the leading end of each of an appropriate number (in the illustrated embodiment, 2) of support members


22


respectively provided on and projected from a plate-shaped member


21


. Here, as the plate-shaped member


21


, there is used a cover which covers the side surface of a printing apparatus


500


.




The rubber cylinder


25


is structured such that it can be contacted with and separated from the plate cylinder


11


and thus, when winding the printing plate


70


onto the plate cylinder


11


, the printing plate


70


can also be held and pressed by and between the plate cylinder


11


and this rubber cylinder


25


. On the contact portion between the plate cylinder


11


and rubber cylinder


25


, specifically, on the side (in

FIG. 1

, on the left side) of such contact portion where the printing plate


70


can be inserted, there is disposed a hand cover


26


having a substantially L-shaped section; and, the hand cover


26


can prevent an operator from having his or her finger caught in error by and between the rubber cylinder


25


and plate cylinder


11


.




On the plate cylinder


11


, as shown in

FIG. 3

, there is wound and fixed a plate base material


27


(a material forming the base part of the plate cylinder


11


) at least one surface of which is formed as a roughened surface in such a manner that the roughened surface becomes an outer surface side thereof. As a sheet-shaped base material used as the plate base material


27


, there can be employed plastics such as polyethylene terephthalate, polypropylene and polyethylene; or, metal such as aluminum and SUS; or, paper or synthetic paper; or, cloth. That is, any material can be used, provided that it can be well fitted with the plate cylinder


11


of the printing apparatus.




The hold roller


17


, as shown in

FIG. 4

, is assembled to an appropriate driving member such as a cylinder


18


and is structured such that it can be contacted with or separated from the outer peripheral surface of the plate cylinder


11


by a driving member controller (not shown). Here, in order not to damage the flexible printing plate


70


, the hold roller


17


may be preferably formed of elastic material such as rubber.




And, as shown in

FIG. 2

, on the upper surface of the lower tooth


12




b


of the plate front end clamp mechanism


12


, there are projectingly provided three or more (in this embodiment, 7) positioning pins


14


in such a manner that they are spaced by a given distance from one another in the axial direction of the plate cylinder


11


. Here, of the seven positioning pins


14


, only one positioning pin


14


shown on the right in

FIG. 2

has a circular section, whereas the other remaining positioning pins


14


are respectively so formed as to have such a section shape that can be obtained by cutting away the two sides of a circle in a direction to cross at right angles to the axial direction of the plate cylinder


11


, in order that the widths of these positioning pins


14


in the axial direction of the plate cylinder


11


are narrower than the width of the positioning pin


14


having the above-mentioned circular section shape in the axial direction of the plate cylinder


11


.




Also, not only in the appropriate portions of the upper tooth


12




a


that respectively correspond to the positions of the positioning pins


14


, but also in the appropriate portions of the plate front end


70




a


of the printing plate


70


, there are formed notches


16


,


71


, respectively.




When mounting the printing plate


70


onto the thus-structured plate cylinder


11


, the operator firstly sets the printing plate


70


on the guide member


20


, pushes the printing plate


70


in such a manner that the plate front end


70




a


is inserted into between the upper tooth


12




a


and lower tooth


12




b


of the plate front end clamp mechanism


12


, and brings the inner peripheral surfaces of the notches


71


of the plate front end


70




a


into contact with the positioning pins


14


shown in

FIG. 2

to thereby position the plate front end


70




a.


In this state, the upper tooth


12




a


is closed to thereby fix the plate front end


70




a.






Next, in the state shown in

FIG. 1

, the plate cylinder


11


is rotated counterclockwise using the rotation controller (not shown) to thereby wind the printing plate


70


onto the plate cylinder


11


, including curved surface portion


11




b.


During the rotational movement of the plate cylinder


11


, at the time when the controller detects the rotational position of the plate cylinder


11


where the hold roller


17


can be contacted with the flat surface portion


11




a


of the plate cylinder


11


, the controller stops the rotational movement of the plate cylinder


11


.




And, as shown in

FIG. 5

, the hold roller


17


is contacted with the flat surface portion


11




a


of the plate cylinder


11


and the printing plate


70


is pressed against the outer peripheral surface of the plate cylinder


11


. Then, the plate cylinder


11


is rotated again counterclockwise using the rotation controller (not shown). In this manner, the hold roller


17


can be so operated as to press the printing plate


70


against the outer peripheral surface of the plate cylinder


11


before and behind the top portions


11




c


of the plate cylinder


11


. At the then time, the hold roller


17


, which is energized by the cylinder


18


toward the outer peripheral surface of the plate cylinder


11


, is allowed to advance and retreat according to the shape of the outer peripheral surface of the plate cylinder


11


.




The plate cylinder


11


is rotated on and, as shown in

FIG. 6

, at the time when the printing plate


70


is wound on the plate cylinder


11


up to the neighboring portion of the plate rear end clamp mechanism


13


, the rotation controller (not shown) stops the rotational movement of the plate cylinder


11


.




At the then time, the operator, as shown in

FIG. 7

, curves the neighboring portion of the plate rear end of the printing plate


70


to thereby insert the plate rear end


70




b


into between the upper tooth


13




a


and lower tooth


13




b


of the plate rear end clamp mechanism


13


. In this state, the plate rear end


70




b


is floated up from the flat surface portion


11




a


of the plate cylinder


11


and the upper surface of the lower tooth


13




b.


And, the plate cylinder


11


is rotated counterclockwise again using the rotation controller (not shown). In this manner, the hold roller


17


can be so operated as to press the printing plate


70


against the outer peripheral surface of the plate cylinder


11


before and behind the top portions


11




c


of the plate cylinder


11


; and, at the same time, as shown in

FIG. 8

, the plate rear end can be closely contacted with the flat surface portion


11




a


of the plate cylinder


11


and the upper surface of the lower tooth


13




b.






Finally, after the upper tooth


13




a


of the plate rear end clamp mechanism


13


is closed to thereby fix the plate rear end, the hold roller


17


is retreated from the printing plate


70


using the rotation controller (not shown), thereby completing the mounting operation of the flexible printing plate onto the plate cylinder


11


.




In the above-structured flexible printing plate-mounting apparatus


10


, the plate front end


70




a


of the flexible printing plate


70


is contacted with the seven positioning pins


14


which are respectively provided on and projected from the lower tooth


12




b


of the plate front end clamp mechanism, thereby positioning the plate front end


70




a.


Therefore, the distance between the positioning pins


14


in the plate cylinder is narrow when compared with the distance provided in the conventional printing plate-mounting apparatus; and thus, even in the case of a printing plate of a large size such as a half-kiku size, there is eliminated a fear that the flexible printing plate


70


can be deformed in such a manner that the plate front end


70




a


is projected from between the positioning pins


14


.




And, in the flexible printing plate-mounting apparatus


10


, since the hold roller


17


presses the flexible printing plate


70


against the top portions (the top portion on the plate front end clamp mechanism


12


side and the top portion on the plate rear end clamp mechanism


13


side)


11




c


of the outer peripheral surface of the plate cylinder


11


including the portions before and behind the top portions of the outer peripheral surface of the plate cylinder


11


, there is no fear that the flexible printing plate


70


wound around the plate cylinder


11


can be floated up from the outer peripheral surface of the plate cylinder


11


. Therefore, there is no need for the operator to pull the plate rear end


70




b


strongly, which can prevent the plate rear end


70




b


against deformation such as stretch. Also, the burden of the operator in the flexible printing plate-mounting operation can be relieved.




In the present embodiment, when fixing the plate rear end


70




b


to the plate rear end clamp mechanism


13


, the operator curves the neighboring portion of the plate rear end


70




b


of the flexible printing plate


70


to thereby insert the plate rear end


70




b


into between the upper tooth


13




a


and lower tooth


13




b


of the plate rear end clamp mechanism


13


. Thanks to this, the plate rear end clamp mechanism


13


need not be structured such that the upper tooth


13




a


can be opened greatly. That is, the structure of the plate rear end clamp mechanism


13


can be simplified.




Also, since, as the plate-shaped member


21


of the guide member


20


, there is used the cover of the printing apparatus


500


, the flexible printing plate-mounting apparatus


10


can be reduced in cost and size.




And, of the seven positioning pins


14


, the width of only one positioning pin


14


in the axial direction of the plate cylinder


11


is set wider than those of the other remaining positioning pins


14


in the axial direction of the plate cylinder


11


. This makes it possible to contact the inner peripheral surfaces of the notches


71


of the flexible printing plate


70


with the positioning pins


14


easily. Also, the flexible printing plate


70


can be positioned accurately by the positioning pin with the plate-cylinder-axial-direction width thereof set wider than those of the other remaining positioning pins


14


.




Also, the plate cylinder


11


can be automatically rotated by the controller, the rotational movement of the plate cylinder


11


can be stopped at a given position, and the hold roller


17


can also be automatically contacted with and separated from the plate cylinder


11


by the controller. This can relieve the burden of the operator further.




And, on the plate cylinder


11


, there is wound and fixed the plate base material


27


at least one surface of which is formed as a roughened surface in such a manner that the roughened surface becomes an outer surface thereof. Due to this, the deformation and positional deviation of the flexible printing plate


70


after the flexible printing plate


70


is contacted with the outer peripheral surface of the plate cylinder


11


can be prevented positively.




In the present embodiment, when the hold roller


17


is contacted with and separated from the plate cylinder


11


, the rotational movement of the plate cylinder


11


is stopped. However, alternatively, by changing the setting of the controller (not shown), the hold roller


17


may be contacted with and separated from the plate cylinder


11


without stopping the rotational movement of the plate cylinder


11


.




Next, description will be given below of embodiment 2-2 of the flexible printing plate-mounting apparatus according to the invention with reference to

FIGS. 9 and 10

. In the flexible printing plate-mounting apparatus according to embodiment 2-2, as a plate cylinder, there is used a conventional plate cylinder


61


which is shown in

FIGS. 19 and 20

. And, on the present plate cylinder


61


, there is wound and fixed the plate base material


27


(see FIG.


3


), which is used in the previously described embodiment 2-1 and at least one surface of which is formed as a roughened surface, in such a manner that the roughened surface becomes an outer surface thereof.




The flexible printing plate-mounting apparatus according to embodiment 2-2 has a similar structure to the flexible printing plate-mounting apparatus


10


(see

FIG. 1

) according to embodiment 2-1, except for the plate cylinder.




In

FIG. 9

, there are shown a flexible printing plate


80


and a pin contact member


30


to be fixed to the plate front end of the flexible printing plate


80


, which are both used in the present embodiment. In the plate front end of the flexible printing plate


80


, more specifically, in the portions of the flexible printing plate


80


front end that correspond to two positioning pins


64


shown in

FIG. 20

, there are formed two notches


81


each having a substantially U-shaped peripheral edge. Also, in the plate front end, there are formed at least three (in this embodiment, 7) fixing holes


82


at appropriate intervals in the width direction (in

FIG. 9

, in the right and left direction) of the flexible printing plate


80


.




The pin contact member


30


includes a band-shaped base


31


which is formed of high-rigidity material such as metal and has a length equal to or greater than the width of the flexible printing plate


80


. In the base


31


, specifically, in the portions of the base


31


that correspond to the two positioning pins


64


shown in

FIG. 20

, there are formed two circular-shaped insertion holes


33


. Also, the base


31


includes at least three (in this embodiment, 7) fixing pins


32


which are provided on and projected from the base


31


at appropriate intervals in the longitudinal direction of the base


31


.




Now, FIG.


10


(A) is an enlarged view of the neighboring portion of each notch


81


of the flexible printing plate


80


, showing a state thereof when the pin contact member


30


shown in

FIG. 9

is fixed to the plate front end of the flexible printing plate


80


. Also, FIG.


10


(B) is a section view taken along the line Y—Y shown in FIG.


10


(A). As shown in FIG.


10


(A), by inserting the fixing pin


32


of the pin contact member


30


into its associated fixing hole


82


of the flexible printing plate


80


, the pin contact member


30


can be fixed to the flexible printing plate


80


. In this case, the pin contact member


30


and flexible printing plate


80


are set such that a portion of the peripheral edge of the circular-shaped insertion hole


33


of the pin contact member


30


coincides with the curved portion of the substantially U-shaped peripheral edge of the notch


81


of the flexible printing plate


80


.




When mounting the flexible printing plate


80


onto the plate cylinder


61


shown in

FIG. 20

, the plate front end of the flexible printing plate


80


may be firstly fixed to the pin contact member


30


and, after then, the plate front end may be fixed to the plate front end clamp mechanism


62


; or, with the two positioning pins


64


of the plate front end clamp mechanism


62


inserted into the two insertion holes


33


of the pin contact member


30


, the plate front end of the flexible printing plate


80


may be fixed to the pin contact member


30


.




As shown by a one-dot chained line in FIG.


10


(B), when the two positioning pins


64


of the plate cylinder


61


are respectively inserted into the two insertion holes


33


of the pin contact member


30


, the inner peripheral surfaces of the notches


81


of the flexible printing plate


80


are respectively contacted with the two positioning pins


64


together with the inner peripheral surfaces of the two insertion holes


33


of the pin contact member


30


.




The operation to wind and mount the flexible printing plate


80


onto the plate cylinder


61


is executed similarly to embodiment 2-1.




In the above-structured flexible printing plate-mounting apparatus, in case where the plate front end of the flexible printing plate


80


is positioned and fixed by the plate front end clamp mechanism, the present plate front end is protected by the high-rigidity pin contact member


30


, thereby preventing the plate front end against deformation. Therefore, with use of the pin contact member


30


, not only the deformation of the printing plate


80


can be prevented without increasing the number of the positioning pins used, but also it is possible to use the plate cylinder


61


of the existing printing apparatus. In case where the present embodiment is enforced using an existing facility, the facility cost of the present embodiment can be reduced to a great extent.




Next, description will be given below of embodiment 2-3 of the flexible printing plate-mounting apparatus according to the invention with reference to

FIGS. 11 and 12

. In embodiment 2-3, the pin contact member


30


used in the previously described embodiment 2-2 is changed but the remaining portions of embodiment 2-3 are similar in structure to embodiment 2-2.





FIG. 11

shows parts which are used in the present embodiment; that is, a flexible printing plate


80


and a pin contact member


40


to be fixed to the plate front end of the flexible printing plate


80


.




The pin contact member


40


includes a band-shaped base


41


which is formed of high-rigidity material such as metal and has a length equal to or greater than the width of the flexible printing plate


80


. In the base


41


, specifically, in the portions of the base


41


that correspond to the two positioning pins


64


shown in

FIG. 20

, there are formed two circular-shaped insertion holes


43


. Also, the base


41


includes at least three (in this embodiment, 7) fixing pins


42


which are provided on and projected from the base


31


at appropriate intervals in the longitudinal direction of the base


41


.




Now,

FIG. 12

is an enlarged view of the neighboring portion of each notch


81


of the flexible printing plate


80


, showing a state thereof when the pin contact member


40


is fixed to the plate front end of the flexible printing plate


80


. As shown in

FIG. 12

, by inserting the fixing pin


42


of the pin contact member


40


into its associated fixing hole


82


of the flexible printing plate


80


, the pin contact member


40


can be fixed to the flexible printing plate


80


. In this case, the pin contact member


40


and flexible printing plate


80


are set such that a portion of the peripheral edge of the circular-shaped insertion hole


43


of the pin contact member


40


coincides with the curved portion of the substantially U-shaped peripheral edge of the notch


81


of the flexible printing plate


80


.




According to the above-structured flexible printing plate-mounting apparatus, after the pin contact member


40


is fixed to the plate front end of the flexible printing plate


80


, when fixing the present plate front end to the plate front end clamp mechanism, the pin contact member


40


can be inserted into between the upper and lower teeth of the plate front end clamp mechanism to thereby position both of the pin contact member


40


and the plate front end of the flexible printing plate


80


. This makes it possible to simplify the plate front end positioning and fixing operation further.




Next,

FIG. 13

shows embodiment 2-4 of the flexible printing plate-mounting apparatus according to the invention. In the flexible printing plate-mounting apparatus


90


according to embodiment 2-4, the upper tooth


93




a


of a plate rear end clamp mechanism


93


provided in a plate cylinder


91


can be pulled apart greatly from the upper face of the lower tooth


93




b


of the plate rear end clamp mechanism


93


: that is, the upper tooth


93




a


can be held in such a manner that it does not cover the upper surface of the lower tooth


93




b.


In embodiment 2-4, the upper tooth


93




a


can be rotated until an angle formed between the lower surface of the upper tooth


93




a


and the upper surface of the lower surface


93




b


becomes equal to or greater than an angle where the plate rear end and the clamp surface of the upper tooth


93




a


are not contacted with each other in a state shown in FIG.


13


.




In the present embodiment, on the plate cylinder


91


, there is wound and fixed a plate base material at least one surface of which is formed as a sticky surface in such a manner that the sticky surface becomes an outer surface thereof.




The sticky surface can be formed, for example, by spraying a spray adhesive onto a sheet-shaped base body, by bonding two-side adhesive tape to the sheet-shaped base body, or by applying sticky material to the base body.




When mounting the flexible printing plate


70


, using a similar process to embodiment 2-1, the plate front end is fixed by a plate front end clamp mechanism


92


, including an upper tooth


92




a


and a lower tooth


92




b,


and the flexible printing plate


70


is wound around the outer peripheral surface of the plate cylinder


91


. And, as shown in

FIG. 13

, at the time when the flexible printing plate


70


is wound around the plate cylinder


91


up to the neighboring portion of the plate rear end clamp mechanism


93


, the upper tooth


93




a


of the plate rear end clamp mechanism


93


is opened wide to thereby set the upper tooth


93




a


in a state in which it does not cover the upper surface of the lower tooth


93




b.






And, as shown in

FIG. 13

, a hold roller


17


is contacted with the curved surface portion of the plate cylinder


91


to thereby press the flexible printing plate


70


against the outer peripheral surface of the plate cylinder


91


and, in this state, the plate cylinder


91


is rotated counterclockwise. In this case, due to the operation of the hold roller


17


, the flexible printing plate


70


can be pressed against the outer peripheral surface of the plate cylinder


91


before and behind the top portions


91




c


of the plate cylinder


91


and, at the same time, the plate rear end


70




b


of the flexible printing plate


70


can be closely contacted with the flat surface portion


91




a


of the plate cylinder


91


and the upper surface of the lower tooth


93




b.






Finally, after the upper tooth


93




a


of the plate rear end clamp mechanism is closed to thereby fix the plate rear end


70




b,


the hold roller


17


is retreated from the flexible printing plate


70


, which completes the mounting of the flexible printing plate


70


onto the plate cylinder


91


.




In the above-structured flexible printing plate-mounting apparatus


90


, since there is eliminated the need that the plate rear end


70




b


of the flexible printing plate


70


is curved and is thereby inserted into between the upper tooth


93




a


and lower tooth


93




b


of the plate rear end clamp mechanism


93


, the flexible printing plate-mounting operation can be simplified further and the-thus simplified operation is suitable for automation as well.




Now,

FIG. 14

shows embodiment 2-5 of the flexible printing plate-mounting apparatus according to the invention. In the flexible printing plate-mounting apparatus


100


according to embodiment 2-5, as the pressure member which is used to press a flexible printing plate


70


against the outer peripheral surface of the plate cylinder


91


at least before and behind the top portions of a plate cylinder


101


(including flat surface portions


101




a,


top portions


101




c,


a plate front end clamp mechanism


102


, and a plate rear end clamp mechanism


103


), there is employed a flat surface pressure member. Here, the flat surface pressure member is structured such that a brush


117


, the leading end portions of which are substantially the same in height so as to form a single flat surface, can be driven by an air cylinder


18


to thereby contact the brush


117


with the plate cylinder


101


and separate the brush


117


from the plate cylinder


101


.




As the brush


117


, there can be employed a brush formed of chemical synthetic fiber such as nylon, polypropylene, vinyl chloride, PBT and aramide; a brush formed of plant fiber (palm); or, a brush formed of animal fiber (pig fur, horsehair, sheep fur).




The operation to wind the flexible printing plate


70


onto the plate cylinder


101


is carried out in a similar manner to embodiment 2-1. However, in the present embodiment, since the flexible printing plate


70


can be pressed against the outer peripheral surface of the plate cylinder


101


over a wide range by the flat surface pressure member, in a process for winding the flexible printing plate


70


, the accuracy of the timing for stopping the rotation of the plate cylinder


101


may be set low.




In the above-structured flexible printing plate-mounting apparatus


100


, since the flexible printing plate


70


can be pressed against the outer peripheral surface of the plate cylinder


101


over a wide range by the flat surface pressure member, the floating of the flexible printing plate


70


from the outer peripheral surface of the plate cylinder


101


can be prevented positively and easily. For example, while rotating and stopping the plate cylinder


101


by hand, the flexible printing plate


70


can be mounted onto the plate cylinder


101


.




In the present embodiment, the brush is structured such that the leading end portions thereof can be so arranged to form a flat surface. However, the leading end portions of the brush may also be so arranged as to form a plurality of flat surfaces, provided that the brush can press the flexible printing plate


70


against the outer peripheral surface of the plate cylinder


101


; for example, the leading end portions of the brush may be arranged such that the section of the brush leading end face is formed as a V shape.




Also, in the present embodiment, the flat surface pressure member is structured by using the brush. However, instead of the brush, there can be used a pad which is formed of sponge (urethane sponge, cellulose sponge) or felt. And, it is also possible to use a pad in which core material such as sponge, felt or rubber is covered with molten (cloth).




Next, description will be given below of embodiment 2-6 of the flexible printing plate-mounting apparatus according to the invention with reference to

FIGS. 15 and 16

.

FIG. 15

is a partially enlarged view of a plate cylinder


111


according to the present embodiment. Within a groove portion


115


formed in the plate cylinder


111


, there are disposed a plate front end clamp mechanism


112


(including an upper tooth


112




a


and a lower tooth


112




b


) and a plate rear end clamp mechanism


113


(including an upper tooth


113




a


and a lower tooth


113




b


). In the lower tooth


112




b


of the plate front end clamp mechanism


112


, there are formed notches each having a rectangular shape when it is viewed from above, in such a manner that they are spaced from each other at a given interval in the axial direction of the plate cylinder


111


; and, in each notch, there is disposed a pin block


119


which is formed integral with the plate cylinder


111


. And, a positioning pin


114


is provided on and projected from the pin block


119


, and is accommodated by notch


116


.




As shown in

FIG. 16

which is a section view taken along the line Y—Y shown in

FIG. 15

, one side surface of the pin block


119


is closely contacted with the side surface of the groove portion


115


.




In the above-structured flexible printing plate-mounting apparatus, the positioning pin


114


is formed integral with the plate cylinder


111


through the pin block


119


. Due to this, the plate front end portion can be positioned with more accuracy.




Next, description will be given below of embodiment 2-7 of the flexible printing plate-mounting apparatus according to the invention with reference to

FIGS. 17 and 18

. Here,

FIG. 17

is a partially enlarged view of a plate cylinder


121


according to embodiment 2-7. Within a groove portion


125


formed in the plate cylinder


121


, there are disposed a plate front end clamp mechanism


122


and a plate rear end clamp mechanism


123


. The clamp mechanisms


122


and


123


respectively include plate-shaped upper teeth


122




a


and


123




a.


In the present embodiment, the upper teeth


122




a


and


123




a


are respectively fixed within the groove portion


125


. And, on the lower surface of the upper tooth


122




a


of the plate front end clamp mechanism


122


, there are projectingly provided positioning pins


124


at given intervals in the axial direction of the plate cylinder


121


.




Now,

FIG. 18

is a section view taken along the line Y—Y shown in FIG.


17


. On the upper portion of a lower tooth


122




b


disposed on the bottom surface of the groove portion


125


, there is disposed a shaft-shaped cam member


130


the diameter of which is reduced at the portions that correspond to the positioning pins


124


hanging from the upper tooth


122




a.


And, between the cam member


130


and upper tooth


122




a,


there is interposed a plate spring


131


. By rotating the cam member


130


, the upper tooth


122




a


and plate spring


131


can opened and closed with respect to each other, which makes it possible to hold the plate front end of the flexible printing plate


70


. That is, in the present embodiment, the plate spring


131


substantially functions as a lower tooth for holding the plate front end between the upper tooth


122




a


and itself.




In the above-structured flexible printing plate-mounting apparatus, the positioning pins


124


are disposed on the upper tooth


122




a


in such a manner that they extend toward the lower tooth


122




b;


and thus, the upper tooth


122




a


is not movable. Therefore, a hold roller can be made to approach very closely to the upper tooth


122




a,


so that the flexible printing plate


70


can be closely contacted with the plate cylinder


121


more positively.




As has been described heretofore, according to the mounting method and apparatus of the invention for mounting a flexible printing plate, especially, a digitally-made flexible printing plate, the dimensional stability of the flexible printing plate in the flexible printing plate-mounting operation and printing operation can be enhanced remarkably, thereby being able to obtain multicolor printing matching accuracy equivalent to that of a metal support member printing plate. Also, the mountability of the flexible printing plate onto a plate cylinder can also be enhanced greatly, which makes it possible to reduce the burden of an operator. Further, since the invention can also be enforced simply by improving an existing printing machine to a slight degree, the facility cost of the invention can be saved.




While the present invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.



Claims
  • 1. A plate-mounting member to be attached to a plate front end of a flexible plate in order to mount said flexible plate having a plurality of fixing holes onto a plate cylinder including a plate front end clamp mechanism having upper and lower teeth and at least two positioning pins disposed between upper and lower teeth, said plate-mounting member comprising a base and a plurality of fixing pins disposed on said base to be respectively inserted into said plurality of fixing holes formed in said plate front end, wherein said base is to be attached to said positioning pins disposed in said plate front end clamp mechanism to thereby position said plate front end,wherein deformation preventative notches are formed in the portions of said base that are to be held by said upper and lower teeth.
  • 2. The plate-mounting member according to claim 1, further comprising means for mounting the plate-mounting member to a plate cylinder, wherein said means for mounting is disposed on said base.
  • 3. The plate-mounting member according to claim 1, wherein said base and said fixing pins are configured and arranged so that when said base is clamped by said plate front end clamp mechanism, said flexible plate is also clamped by said plate front end clamp mechanism.
  • 4. The plate-mounting member according to claim 1, wherein the plate is positioned by notches upon mounting onto the plate cylinder.
  • 5. The plate-mounting member according to claim 1, wherein said plurality of fixing pins are disposed on said base along the width direction of said plate and the distance between adjacent fixing pins is not more than 400 mm.
Priority Claims (2)
Number Date Country Kind
P. 2000-043031 Feb 2000 JP
P. 2000-070598 Mar 2000 JP
US Referenced Citations (7)
Number Name Date Kind
1788662 Creed Jan 1931 A
2553856 Janke May 1951 A
3406629 Hoexter Oct 1968 A
3537395 Prince et al. Nov 1970 A
5555811 Ruckmann et al. Sep 1996 A
5562039 Fox et al. Oct 1996 A
6474236 Naniwa et al. Nov 2002 B1
Foreign Referenced Citations (2)
Number Date Country
0 950 925 Oct 1999 EP
840 745 Jul 1960 GB