Sheet media handling system and printer having the same

Information

  • Patent Grant
  • 6629693
  • Patent Number
    6,629,693
  • Date Filed
    Friday, October 26, 2001
    23 years ago
  • Date Issued
    Tuesday, October 7, 2003
    21 years ago
Abstract
A sheet media handling system suitable for use with a printer is disclosed. The sheet media handling system includes a first support and a second support adjacent the first support. In use, the first support supports first sheet media and second sheet media on the first sheet media. The second support supports a portion of second sheet media that is not supported by the underlying first sheet media. A biasing means biases the second support. The biasing means is collapsible under the portion of up to a predetermined number of sheets of the second sheet media. During a pick cycle when the first support is moved to present supported media thereon to an infeed zone of the printer, the portion topmost of the second sheet media is brought to within a predetermined tolerance of the infeed zone.
Description




BACKGROUND




This invention relates to a sheet media handling system and a printer having the same for supporting both small and large width sheet media. More particularly, this invention relates to a sheet media handling system and printer having the same for presenting a large width sheet medium, that is partially supported by a stack of small width sheet media, substantially aligned to an infeed zone of the printer.




Office equipment such as photocopiers, laser printers, ink jet printers and other imprinting mechanisms today incorporate an ability to receive sheet media from any one of two or more trays. It is very common to have a bypass tray in which a single sheet medium of a special type or of a different size can be conveniently fed for particular printing without having to load it onto pull-out trays.





FIG. 1A

shows one prior art media handling system having a pressure plate pivotably mounted on a base of a printer. During a pick cycle, the pressure plate is lifted to move a stack of sheet media located above it to an infeed zone of the printer. This pressure plate is usually designed to directly support a stack of sheet media in a main tray. During each pick cycle, the sheet at the top of the stack will be moved to the infeed zone. A simple and economical design of a bypass feeding system usually has a bypass tray positioned above the main tray. Sheet media in this bypass tray is supported either by the pressure plate itself (when there is no sheet medium in the main tray) or by a stack of sheet media in the main tray as shown in FIG.


1


A. Such a design accords pick priority to any sheet medium in the bypass tray over that in the main tray. This design works well when the sheet media on both the bypass and main trays are of substantially the same width. When the media are of substantially the same widths, the sheet media in the main tray will be able to provide sufficient support for the sheet media in the bypass tray.




However, a serious problem results when the sheet medium in the bypass tray is substantially wider than a stack of sheet media in the main tray. For example, the sheet media in the bypass tray is of B4 size and the sheet media in the main tray is of A4 or Letter size. A substantially large portion of the B4 size sheet medium in the bypass tray will not be supported by the A4 or Letter size sheet media in the main tray. The problem is not so serious when there is only a small stack of sheet media in the main tray. A small stack will create only a small height differential between portions of the B4 size sheet medium. In such a case, the B4 size sheet medium is still fairly well supported, partly by the stack of sheet media in the main tray and partly by the exposed portion of the pressure plate. As a result, the B4 size sheet medium can be properly presented for picking by the pick mechanism in the printer.




However, when the stack height of the smaller width sheet media in the main tray measures half an inch or more, a relatively large portion of the B4 size sheet medium would not be supported by the pressure plate and would sag at the arris of the stack of sheet media in the main tray as shown in FIG


1


A. Such sagging is detrimental to the aligned feeding of the B4 size sheet medium into the printer as the sheet medium will not be properly presented to the pick mechanism. The pick mechanism is only able to properly engage the portion of the B4 size sheet medium that is supported by the stack of sheet media in the main tray as shown in FIG.


1


B. As a result, the properly engaged portion will be drawn into the printer ahead of the rest of the sheet medium. Such an action would cause the sheet medium to follow an oblique course or a deviation from a predetermined straight line path when being received into the printer. Such unbalanced drawing in of the B4 size sheet medium results in skewing of the sheet medium. This skewing causes undesirable result, for text printed on the skewed sheet medium will appear misaligned, crooked or oblique. In some cases, when the skew is severe, the sheet medium may end up jamming the printer.




A two-part pressure plate disclosed in the U.S. Pat. No. 6,152,440 can be used to overcome the problem of unbalanced support or sagging of the B4 size sheet medium. The pressure plate includes a primary pressure plate for supporting media in the main tray and a secondary pressure plate that is raised to support portions of a larger width sheet media that is not supported by media in the main tray. The secondary pressure plate is actuated by a mechanism that is responsive to a media guide used to align a stack of sheet media in the main tray. Although such a design works well, it is not possible to implement the mechanism where space is a constraint. The secondary pressure plate is also inoperative if a user forgets to move the media guide into position against the stack of sheet media in the main tray.




SUMMARY




According to an embodiment of the present invention, there is provided a sheet media handling system suitable for use with a printer. The sheet media handling system includes a first support and a second support adjacent the first support. In use, the first support supports first sheet media and second sheet media on the first sheet media. The second support supports a portion of second sheet media that is not supported by the underlying first sheet media. A biasing means biases the second support. The biasing means is collapsible under the portion of up to a predetermined number of sheets of the second sheet media. During a pick cycle when the first support is moved to present supported media thereon to an infeed zone of the printer, the portion topmost of the second sheet media is brought to within a predetermined tolerance of the infeed zone.




Further according to the embodiment of the present invention, there is provided a printer that includes the above sheet media handling system.











BRIEF DESCRIPTION OF DRAWINGS




The invention will be better understood with reference to the drawings, in which:





FIGS. 1A and 1B

are representative drawings showing a prior art sheet media handling system that includes a single pressure plate that is unable to provide adequate support of a larger width sheet media that is only partially supported by a smaller width sheet media thereunder;





FIG. 2

is an isometric drawing of a portion of an ink jet printer having a sheet media handling system according to an embodiment of the present invention, the sheet media handling system has a first support and a second support that is biased by a biasing means;





FIG. 3

is an isometric drawing of a pull-out tray that supports the first support and the second support in

FIG. 2

;





FIG. 4

is an isometric drawing of the pull-out tray in

FIG. 3

shown attached to a printer to allow the biasing means that is supported on the ink jet printer to bias the second support;





FIG. 5

is an exploded drawing of the biasing means in

FIG. 2

;





FIG. 6

is an isometric drawing of the biasing means shown assembled to the ink jet printer;





FIGS. 7A and 7B

are representative drawings of the first support and the second support of

FIG. 2

outside of and during a pick cycle of the ink jet printer respectively;





FIGS. 8A and 8B

are drawings similar to

FIGS. 7A and 7B

, showing the first support and the second support supporting a small stack of large width sheet media;





FIGS. 9A and 9B

are drawings similar to

FIGS. 7A and 7B

, showing the first support and the second support supporting a relatively larger stack of large width sheet media than that shown in

FIGS. 8A and 8B

;





FIGS. 10A and 10B

are drawings similar to

FIGS. 7A and 7B

, showing a large stack of small width sheet media supported by the first support and a small stack of large width sheet media that is partially supported by the stack of small width sheet media and partially supported by the second support;





FIGS. 11A and 11B

are drawings similar to

FIGS. 10A and 10B

, showing the support of a larger stack of large width sheet media than that shown in

FIGS. 10A and 10B

; and





FIG. 12

is a side elevation drawing of an alternative biasing means.











DETAILED DESCRIPTION




Hereafter, a preferred embodiment of the present invention will be described in the context of an ink jet printer having a main media tray and a bypass tray. However, it is to be understood that the invention is usable with any imprinting or sheet handling equipment that receives a larger width sheet media that is partially supported by a smaller width sheet media thereunder.





FIG. 2

is an isometric view of a portion of an ink jet printer


2


with a sheet media handling system partially implemented in a pull-out tray


4


.

FIG. 3

is an isometric view of the pull-out tray


4


. The printer


2


includes a bypass tray, generally indicated by a reference numeral


6


, that is located above the pull-out tray


4


. The pull-out tray


4


includes pivotably supported adjacent first and second supports


8


,


10


(

FIG. 3

) that can be tilted largely independently of each other. The first support


8


however includes an engagement portion


9


(

FIG. 4

) which when allowed to do so engages the second support


10


to tilt the second support


10


together with the first support


8


.




Typically, the bypass tray


6


includes an exposed panel


12


on which sheet media may be placed, guided and supported by either the first and the second supports


8


,


10


of the pull-out tray


4


or any sheet media supported thereon. The printer


2


has a pick mechanism


14


that defines an infeed zone, generally indicated by a reference numeral


16


.




A cam (not shown) attached to the pick mechanism holds the first support


8


in an unused position away from the infeed zone


16


when the printer


2


is not in a pick cycle. During the pick cycle, the first support


8


is biased towards the infeed zone


16


. When biased, the first support


8


moves towards the infeed zone


16


to present a sheet medium for picking by the pick mechanism


14


. If sheet media are present in both the pull-out tray


4


and the bypass tray


6


, the topmost sheet medium in the bypass tray


6


will be picked. If there are only sheet media in the pull-out tray


4


, the topmost sheet medium in the pull-out tray


4


will be picked.




After a sheet medium is drawn into the infeed zone


16


of the printer


2


, the sheet medium is advanced into a print zone (not shown) of the printer


2


for printing. During the advancing of the sheet medium, the cam is rotated to move the first support


10


away from the infeed zone


16


so that no new sheet medium can be drawn into the printer


2


.




The width of the second support


10


is determined by the sizes of sheet media to be supported by the sheet media handling system. In this preferred embodiment, it is determined that the smaller width sheet media to be supported include A4, Letter and other smaller sizes. Accordingly, the width of the first support


8


is selected to be about 10 inches. The width of the second support


10


is appropriately selected so as to provide the necessary support for larger width sheet media, such as B+ media. Accordingly, the width of the second support is selected to be about 4 inches.




The pull-out tray


4


includes a leading side wall


18


and an orthogonal aperture


20


(

FIG. 4

) having a first aperture portion


22


formed under an overhanging portion


24


in the leading side wall


18


and a second aperture portion


26


formed on a base


28


of the pull-out tray


4


located under the second support


10


. When the pull-out tray


4


is attached to the printer


2


as shown in

FIG. 4

, a biasing means


30


extends into the pull-out tray


4


through the orthogonal aperture


20


to engage the second support


10


to thereby bias it.





FIG. 5

is an exploded drawing of the biasing means


30


. The biasing means


30


includes a first or leading lever


32


having a first stepped end


34


pivotably mounted to the printer base


28


. The biasing means also includes a coil spring


36


that has one end anchored onto the base


28


of the printer


2


and the other end seated in a seat


37


formed on an undersurface of the first lever


32


. The coil spring


36


is preferably a spiral that is collapsible to a low profile so as not to limit the height of a stack of sheet media placed in the pull-out tray


4


.




When assembled, the coil spring


36


biases the first lever


32


to raise a second bifurcated end


38


of the first lever


32


to define a first incline


40


. The biasing means


30


also includes a second or trailing lever


42


that has a first end


44


pivotably attached to the raised second end


38


of the first lever


32


. The first end


44


is pivotably attached for example by snap fitting a catch


46


of the second lever


42


onto a hinge bar


48


of the first lever


32


. When attached in this manner, a free second end


50


of the second lever


42


extends in an opposite direction to the first lever


32


to define a second incline


52


.




When the pull-out tray


4


is slid along the printer base


28


for attachment to the printer


2


, there will come a point where the overhanging portion


24


of the leading side wall


18


comes into contact with the first incline


40


defined by the biased first lever


32


. As the pull-out tray


4


slides further along, the overhanging portion


24


pushes the first lever


32


down towards the printer base


28


. The overhanging portion


24


will continue to push the first lever downwards until the overhanging portion


24


is moved beyond the second end


38


of the first lever


32


to rest on the second incline


52


of the second lever


42


. During the sliding of the pull-out tray


4


, the second support


10


rides up the first incline


40


. As the overhanging portion


24


clears the first lever


32


, the compressed coil spring


36


extends to bias the second support


10


to its datum position. The overhanging portion


24


will eventually come to rest on the second incline


52


as shown in FIG.


4


. When the pull-out tray


4


is drawn out of the printer


2


, the overhanging portion


24


rides up the second incline


52


to push the second lever


42


downwards to allow the overhanging portion


24


to clear the biasing means


30


.




The second lever


42


includes two arms


54


laterally extending from the second end


50


of the second lever


42


.

FIG. 6

shows the biasing means


30


assembled on the printer


2


. The arms


54


are disposed behind an aperture


56


in a retaining wall


58


. The coil spring


36


is slightly compressed to urge the second end


50


of the second lever


42


against a portion of the retaining wall


18


that defines the top of the aperture


56


. As a result, upward movement of the biasing means


30


is limited and the biasing means


30


is therefore firmly held in place to prevent it from being dislodged during transportation of the printer


2


.




The operation of the sheet media handling system is next described with the aid of

FIGS. 7A-11A

and


7


B-


11


B that show a representative first support


8


and a biased second support


10


supporting different sheet media.

FIG. 7A

shows the second support


10


biased to the datum position when no medium is placed on the pull-out tray


4


that is attached to the printer


2


. In the datum position, it is preferable that the second support


10


does not come into immediate contact with the pick mechanism


14


as any contact may cause unnecessary wear and produce unwanted noise during operation of the printer


2


.




During the pick cycle of the printer, as the first support


8


is moved towards the infeed zone


16


, the engagement portion engages an under surface of the second support


10


to thereby move the second support


10


together with the first support


8


to the infeed zone


16


as shown in FIG.


7


B. When engaged in this manner, the upper surface of the second support


10


is substantially flush with the upper surface of the first support


8


. Such a flush arrangement allows a sheet medium to be presented substantially flat to the pick mechanism


14


to prevent skew of the sheet medium. Between the datum position and the infeed zone


16


, the second support


10


moves in accordance with the movement of the first support


10


.





FIG. 8A

shows a small stack


70


of large width sheet media placed either in the pull-out tray


4


or the bypass tray


6


. The first support


8


supports a first portion of the stack


70


while the second support


10


supports a second portion


74


of the stack


70


. The second support


10


collapses under the weight of the second portion


74


to maintain a topmost sheet


76


of the stack


70


clear of the infeed zone


16


when outside of the pick cycle.

FIG. 8B

shows the second support


10


raised together with the first support


8


to present the topmost sheet


76


to the infeed zone


16


during the pick cycle.





FIG. 9A

shows a larger stack


80


of large width sheet media supported by the first


8


and the second support


10


. Under the larger stack


80


, the second support


10


collapses even more than that shown in

FIG. 8A

to maintain a topmost sheet


82


clear of the infeed zone


16


when the printer is not in a pick cycle.

FIG. 9B

is similar to

FIG. 8B

, showing the second support


10


being raised by the first support


8


to jointly present the topmost sheet


82


of to the infeed zone


16


.





FIG. 10A

shows the first support


8


supporting a stack


90


of smaller width sheet media that supports a first portion


72


of a small stack


70


of larger width sheet media placed thereon. The second support


10


supports a second portion


74


of the stack


70


. The stack


70


is therefore supported partially by the second support


10


and partially supported by the stack


90


of smaller width sheet media. The second support


10


collapses under the weight of the second portion


74


to define an offset between the first and the second portions


72


,


74


of the larger width sheet media. During the pick cycle, as the first support


8


is raised to present the topmost sheet


76


to the infeed zone


16


, the second support


10


though not engaged by the first support


8


rises with the first support


8


. This rising of the second support


10


moves the second portion


74


of the topmost sheet


76


(the second portion


74


topmost of the stack


70


) to within a predetermined tolerance X from the infeed zone


16


as shown in FIG.


10


B.





FIGS. 11A and 11B

, which are similar to

FIGS. 10A and 10B

, show a larger stack


80


of the larger width sheet media placed on the stack


90


of smaller width sheet media. Due to the higher load on the second support


10


, the second support


10


collapses more than that shown in

FIGS. 10A and 10B

to produce a larger offset between the first and second portions of the larger width sheet media. As long as the number of sheets of the larger width sheet media is kept to a predetermined number, the second portion of the topmost sheet


76


will be raised to within the predetermined tolerance X when the first support


8


is raised. The topmost sheet


76


will be received into the printer following substantially a straight media path.




Advantageously, the sheet handling system according to the embodiment of the present invention requires lesser space to implement than the prior art system disclosed in U.S. Pat. No. 6,152,440. The system is also user-friendlier in that a user needs not worry about manually activating the second support.




Although the present invention is described as implemented in a sheet media handling system having a separate bypass tray, the invention may also be implemented in a system having only a single main tray capable of accommodating sheet media of different widths. The main tray is also not limited to a pull-out tray as described. The main tray may be a receptacle in the printer with an opening for media to be inserted. In such a design, the first and second supports


8


,


10


are pivotably attached to the base


28


of the printer


2


and the biasing means


30


may simply be a coil spring for directly biasing the second support. In the embodiment shown in

FIG. 2

, the biasing means


30


may be replaced with a leaf spring


100


as shown in

FIGS. 12A and 12B

.

FIG. 12A

shows the leaf spring


100


being biased only by the second support


10


, and

FIG. 12B

shows the leaf spring


100


being further biased by a portion of sheet media on the second support


10


. The leaf spring


100


is appropriately shaped and sized to bias the second support


10


according to the operational principles described above.



Claims
  • 1. A system for handling differing-width first and second sheet media in a printer comprising:a first support for supporting first sheet media thereon; a second support adjacent the first support for jointly supporting second sheet media wider than the first sheet media, the second support being for supporting a portion of the second sheet media not supported by the first support or by the first sheet media supported thereon; and a biasing means for biasing the second support, wherein the biasing means is collapsible under a portion of up to a predetermined number of sheets of the second sheet media such that the portion topmost in the second sheet media is only brought to within a predetermined tolerance of an infeed zone of the printer during a pick cycle when the first support is moved to present supported media thereon to the infeed zone.
  • 2. A system according to claim 1, further including an engagement portion supported by the first support or the second support to allow the second support to be engaged and moved together with the first support during the pick cycle.
  • 3. A system according to claim 1, further including a pull-out tray that supports the first and the second supports, the pull-out tray being slidable on a base of the printer for attachment to the printer.
  • 4. A system according to claim 3, wherein the biasing means is supported on the base of the printer.
  • 5. A system according to claim 4, wherein the biasing means includes a leaf spring.
  • 6. A system according to claim 4, wherein the biasing means includes:a first lever having a first end pivotably mounted to the base of the printer; and a coil spring for biasing the first lever to raise a second end of the first lever to define a first incline; whereby when the pull-out tray is slidably attached to printer, the second support moves up the first incline to thereby be biased.
  • 7. A system according to claim 6, wherein the biasing means further includes a second lever having a first end pivotably attached to the raised second end of the first lever and having a second end that extends in an opposite direction to the first lever to define a second incline.
  • 8. A system according to claim 7, wherein the second lever includes at least one arm laterally extending from the second end and the sheet media handling system further including a retaining wall that engages the arm to hold the biasing means in place by compressing the coil spring.
  • 9. A system according to claim 6, wherein the coil spring is a spiral.
  • 10. A printer comprising:a pick mechanism that defines an infeed zone; and a sheet media system for handling first and second sheet media of differing widths including: a first support for supporting first sheet media thereon; a second support adjacent the first support for jointly supporting second sheet media wider than the first sheet media, the second support being for supporting a portion of the second sheet media not supported by the first support or by the first sheet media supported thereon; and a biasing means for biasing the second support, wherein the biasing means is collapsible under a portion of up to a predetermined number of sheets of the second sheet media such that the portion topmost of the second sheet media is only brought to within a predetermined tolerance of the infeed zone during a pick cycle when the first support is moved to present supported media thereon to the infeed zone.
  • 11. A printer according to claim 10, wherein the sheet media system further includes an engagement portion supported by the first support or the second support to allow the second support to be engaged and moved together with the first support during the pick cycle.
  • 12. A printer according to claim 10, further including a pull-out tray that supports the first and the second supports, the pull-out tray being slidable on a base of the printer for attachment to the printer.
  • 13. A printer according to claim 12, wherein the biasing means is supported on the base of the printer.
  • 14. A printer according to claim 13, wherein the biasing means includes a leaf spring.
  • 15. A printer according to claim 13, wherein the biasing means includes:a first lever having a first end pivotably mounted to the base of the printer; and a coil spring for biasing the first lever to raise a second end of the first lever to define a first incline; whereby when the pull-out tray is slidably attached to printer, the second support moves up the first incline to thereby be biased.
  • 16. A printer according to claim 15, wherein the biasing means further includes a second lever having a first end pivotably attached to the raised second end of the first lever and having a second end that extends in an opposite direction to the first lever to define a second incline.
  • 17. A printer according to claim 16, wherein the second lever includes at least one arm laterally extending from the second end and the sheet media handling system further including a retaining wall that engages the arm to hold the biasing means in place by compressing the coil spring.
  • 18. A printer according to claim 15, wherein the coil spring is a spiral.
  • 19. A sheet media handling system for a printer comprising:a first support for supporting first sheet media thereon; a second support adjacent the first support for jointly supporting second sheet media wider than the first sheet media, the second support being for supporting a portion of the second sheet media not supported by the first support or by the first sheet media supported thereon; and a biasing means for biasing the second support, the biasing means being collapsible under a portion of up to a predetermined number of sheets of the second sheet media such that the portion topmost in the second sheet media is only brought to within a predetermined tolerance of an infeed zone of the printer during a pick cycle when the first support is moved to present supported media thereon to the infeed zone.
US Referenced Citations (4)
Number Name Date Kind
5573234 Petocchi Nov 1996 A
5595380 McCue et al. Jan 1997 A
6152440 Yip et al. Nov 2000 A
6169561 Fisher, Sr. Jan 2001 B1
Foreign Referenced Citations (1)
Number Date Country
6-87539 Mar 1994 JP