SHEET POST-PROCESSING APPARATUS AND SHEET POST-PROCESSING METHOD
To provide a sheet post-processing apparatus for stapling and ejecting sheets conveyed from an image forming apparatus. The sheet post-processing apparatus comprises a processing tray to load the sheets conveyed from the image forming apparatus and a stapler to staple a sheet bundle of the sheets loaded on the processing tray, and the stapled sheet bundles are led to a sheet receiving tray and are ejected so that the stapling positions of the plurality of sheet bundles loaded on the sheet receiving tray are shifted from each other at each upper and lower stages.
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This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2005-368279 filed on Dec. 21, 2005, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION1. Field of the Invention
The present invention relates to a sheet post-processing apparatus and a sheet post-processing method for post-processing sheets ejected from an image forming apparatus such as a copier, a printer, or a composite device.
2. Description of the Related Art
In recent hears, in the image forming apparatus, to sort sheets after image forming or to perform a post process of sheets such as a stapling process, a sheet post-processing apparatus may be installed in the neighborhood of a sheet ejection section of the main body of the image forming apparatus. For example, the sheet post-processing apparatus for performing the stapling process aligns and staples a plurality of sheets (sheet bundles) by an aligning means, ejects the stapled sheet bundles to a sheet receiving tray, and stacks sequentially these sheet bundles on the sheet receiving tray.
For example, in U.S. Pat. No. 5,263,697, a stapling structure including a binding means for binding recording sheets ejected from the image forming apparatus, a moving means for moving the binding means along a plurality of binding positions of recording sheets, and a position control means for controlling the position of the moving means so as to make the final binding position of the present recording sheets coincide with the starting binding position of the next recording sheets is disclosed.
In the stapling structure disclosed in U.S. Pat. No. 5,263,697, the movement distance and movement time of the binding means can be reduced, though stapled recording sheets, when sequentially ejected, are ejected in the state that the binding positions are overlaid each other, so that the recording sheets bulge when stacked on the sheet receiving tray, thus it is necessary to restrict the number of stacking sheets. Further, when the succeeding sheet bundle stapled is ejected, a problem arises that it presses out the sheet bundle erased already on the tray.
There is a conventional sheet post-processing apparatus available which can perform the stapling process. However, a problem arises that when recording sheets are ejected and stacked on the sheet receiving tray, the stapling positions are overlaid each other, thus the number of stacking sheets is limited and by the succeeding sheet bundle stapled, the sheet bundle on the sheet receiving tray is pressed out and broken.
SUMMARYAn aspect of the present invention is to provide a sheet post-processing apparatus and a sheet post-processing method for reducing breaking of the stack when ejecting stapled sheets.
An embodiment of the present invention provides a sheet post-processing apparatus for stapling and ejecting sheets conveyed from an image forming apparatus, comprising a processing tray to load the sheets conveyed from the image forming apparatus; stapling means for stapling a sheet bundle of the sheets loaded on the processing tray; and ejection means for leading the stapled sheet bundle to a sheet receiving tray and ejecting the same so as to shift the stapling positions of the plurality of sheet bundles loaded on the sheet receiving tray from each other at each upper and lower stages.
Furthermore, an embodiment of the present invention provides a sheet post-processing method for stapling and ejecting sheets conveyed from an image forming apparatus, comprising loading the sheets conveyed from the image forming apparatus on a processing tray; stapling a sheet bundle of the sheets loaded on the processing tray by a stapler; and leading the stapled sheet bundles to the sheet receiving tray and ejecting the same so as to shift the stapling positions of the plurality of sheet bundles loaded on the sheet receiving tray from each other at each upper and lower stages.
BRIEF DESCRIPTION OF THE DRAWINGS
Hereinafter, an embodiment of the present invention will be explained in detail with reference to the accompanying drawings. Further, in the drawings, to the same parts, the same numerals are assigned and duplicated explanation will be omitted.
Embodiment 1
The concrete constitution and operation of each unit shown in
Paper P on which an image is formed by image forming apparatus 5 such as a copier is ejected by a pair of exit rollers 6 and is conveyed by sheet post-processing apparatus 7. Sheet post-processing apparatus 7, as shown in
Paper P ejected from pair of exit rollers 6 of image forming apparatus 5 is received by a pair of entrance rollers 22 installed in the neighborhood of the take-in port of sheet post-processing apparatus 7. Entrance rollers 22 are composed of entrance upper roller 22a and entrance lower roller 22b. Entrance rollers 22 are driven by motor for driving the entrance rollers 26 (
On the downstream side of entrance rollers 22, gate G for branching sheets P received by entrance rollers 22 to two paths (flow paths) is installed. Gate G has a sectional shape of a wedge and the pointed part of the wedge is directed toward the neighborhood of the rolling surfaces of entrance rollers 22. Gate G is rotatably born by the side wall inside sheet post-processing apparatus 7. The pointed part of the wedge takes the first position pointing to entrance upper roller 22a of entrance rollers 22 and the second position pointing to entrance lower roller 22b thereof.
Namely, the first position is used to select the path when the post process is required for sheet P and the second position is used to select the path when the post process is not required for sheet P.
When gate G is at the first position, sheet P is fed to first sheet feed rollers 24 and is sent from first sheet feed rollers 24 to queuing tray 10. Between entrance rollers 22 and queuing tray 10, sheet path guide 36 (
On the downstream side of queuing tray 10, processing tray 12 for stacking sheets P dropped and fed from queuing tray 10 is arranged. Processing tray 12, while sheets P are stapled by stapler 14 which is a processing mechanism for performing the post process, aligns and supports sheets P stacked.
When sheets of a predetermined number are accumulated on queuing tray 10, as shown in
Stapler 14, as shown in
Upper and lower longitudinal aligning rollers 38a and 38b serve as bundle conveying rollers for grasping sheet bundle T after ending of the stapling process and taking out it from stapler 14. Upper longitudinal aligning roller 38a is driven by motor for driving the upper longitudinal aligning roller 40 and lower longitudinal aligning roller 38b is driven by motor for driving the lower longitudinal aligning roller 42.
Further, when sheet P is dropped and fed to processing tray 12, at the position where the rear end of sheet P is dropped, paddle 44 rotatable for aligning sheet P at the uppermost position loaded on processing tray 12 in the longitudinal direction is arranged.
Paddle 44, as shown in
At the end of processing tray 12 on the side of stapler 14, stopper 45 for making contact with the rear end of sheet P and restricting the rear end position is installed. Almost at the center of processing tray 12, conveying belt 50 for conveying sheet bundle T which is stapled and is taken out from stapler 14 by upper and lower longitudinal aligning rollers 38a and 38b up to first sheet receiving tray 16 or second sheet receiving tray 18 is installed. To conveying belt 50, hook 50a for hooking the rear end of sheet bundle T is attached.
Queuing tray 10 can drop and feed sheets P to processing tray 12, though it can be used to convey sheets P toward first sheet receiving tray 16 or second sheet receiving tray 18, and the conveyance of sheets P toward sheet receiving trays 16 and 18 is executed by bringing queuing tray roller 28 into contact with sheets P on queuing tray 10. Queuing tray roller 28 is controlled in the vertical movement by source for driving the queuing tray roller 30 and is driven to rotate by motor for driving the queuing tray roller (
As shown in
As shown in
Queuing tray 10 is slidden and moved by queuing tray motor 34 (
As shown in
Further, by motors 26, 34, 40, 42, 46, and 48 for driving the various mechanisms aforementioned and drivers 49 and 52 are driven and controlled by a control circuit (not drawn).
Next, the operation of sheet post-processing apparatus 7 will be explained in accordance with the flow of sheets. When sheets P with an image formed by image forming apparatus 5 are fed from exit rollers 6, sheet post-processing apparatus 7, depending on (1) a case that sheets P are not post-processed, (2) a case that sheets P are post-processed and preceding sheet P finishes the post processing, and (3) a case that sheets P are post-processed and preceding sheet P is in execution of the post processing, performed different operations.
Firstly, in (1) the case of no execution of the post processing, the pointed part of the wedge of gate G is almost at the second position pointing to entrance lower roller 22b. Papers P fed from entrance rollers 22 are fed to second sheet feed rollers 60 and furthermore are fed to third sheet feed rollers 61. Papers P fed from the third sheet feed rollers are ejected to fixed tray 19 on the top.
Next, (2) the case that the post process (the stapling process) is performed and there are no preceding sheets P on processing tray 12 will be described. At this time, queuing tray 10 slides and moves tray members 10a and 10b respectively up to the positions indicated by the dotted lines shown in
At time of drop and feed, upper longitudinal aligning roller 38a is shifted upward and receiving portion 44a of paddle 44 receives the rear ends of sheets P. Both sides of sheets P are dropped by keeping contact with transversal aligning plates 47a and 47b so as to align sheets P in the transverse direction. Next, paddle 44 rotates in the direction of arrow o shown in
Furthermore, paddle 44 sends sheets P in the direction of arrow q by sending portion 44c, and the rear ends of sheets P make contact with stopper 45, and the alignment of sheets P in the longitudinal direction is completed. Further, the alignment of sheets P in the longitudinal direction on processing tray 12 may be executed by upper longitudinal aligning plate 38a by moving it up and down each time.
By aligning sequentially sheets P with an image formed in the transverse direction and longitudinal direction in this way, sheets P are stacked from sheet feed rollers 24 directly on processing tray 12. When sheets P reach a predetermined number, stapler 14 staples sheets P on processing tray 12 at a desired position in a bundle shape and forms sheet bundle T. Hereafter, as shown in
The rear end of sheet bundle T, when passing through upper and lower longitudinal aligning rollers 38a and 38b, is hooked by hook 50a of conveying belt 50 rotating in the direction of arrow t shown in
Further, first sheet receiving tray 16 is arranged at an inclination angle of θ2 and the front end of each sheet is positioned higher than the rear end thereof, so that preceding sheet bundle T ejected on first sheet receiving tray 16 will not be pressed out by making contact with the front end of succeeding sheet bundle T. Further, even if preceding sheet bundle T is slightly shifted by succeeding sheets P, first sheet receiving tray has an inclination angle of θ2, so that sheet bundle T drops by its own weight and the stapling process of sheets P aligned and stacked in the state that the rear ends are aligned on first sheet receiving tray 16 is completed.
In this way, sheets are sequentially stacked on first sheet receiving tray 16. Further, first sheet receiving tray 16 is arranged at an inclination angle of θ2 and the front end of each sheet is positioned higher than the rear end thereof, so that for example, even if sheets P are ejected onto first sheet receiving tray 16 in the state that they are curled convexly, preceding sheets loaded on first sheet receiving tray 16 will not be pressed out by making contact with the front ends of succeeding sheets P. Namely, ejected sheets P are sequentially loaded on first sheet receiving tray 16 without disturbing the order.
Next, (3) the case that the stapling process is performed and preceding sheets P in execution of the stapling process remain on processing tray 12 will be described. At this time, queuing tray 10 slides and moves tray members 10a and 10b respectively from the positions indicated by the dotted lines shown in
Papers P loaded on queuing tray 10 are sent toward queuing stoppers 10c and 10d by queuing tray roller 28 which drops down onto queuing tray 10 and rotates in the opposite direction of the direction of arrow f shown in
Fed sheets P are sequentially loaded on queuing tray 10 without disturbing the order. Further, even if preceding sheets P are pressed and slightly shifted by succeeding sheets P, queuing tray 10 has an inclination angle of θ1, so that sheets P drop by the own weight down to the position where the rear ends make contact with queuing stoppers 10c and 10d and are aligned and stacked in the state that the rear ends are aligned on queuing tray 10.
During this period, when preceding sheets P on processing tray 12 are ejected on the side of first sheet receiving tray 16 and processing tray 12 becomes empty, queuing tray 10 slides and moves tray members 10a and 10b from the positions indicated by the solid lines shown in
By doing this, for example, two sheets P waiting on queuing tray 10, when tray members 10a and 10b reach the positions indicated by the alternate long and short dash lines shown in
Lower side sheet P of two sheets P dropped from processing tray 12 is sent in the direction of arrow q by lower longitudinal aligning roller 38b rotating in the opposite direction of the direction of arrow s shown in
Third and subsequent sheets P ejected from image forming apparatus 5 are dropped and fed directly to processing tray 12 from the interval between tray members 10a and 10b without waiting on queuing tray 10. Third and subsequent sheets P are sequentially aligned on sheets P which are previously loaded on processing tray 12 by paddle 44.
When sheets P loaded on processing tray 12 reach a predetermined number, sheets P are stapled by stapler 14 and sheet bundle T is formed. Hereafter, sheet bundle T is conveyed toward first sheet receiving tray 16 by upper and lower longitudinal aligning rollers 38a and 38b, and furthermore the rear end thereof is hooked by hook 50a of conveying belt 50, and sheet bundle T is ejected onto first sheet receiving tray 16, and the stapling process of sheets P is completed.
The aforementioned is the explanation of the whole operation of sheet post-processing apparatus 7. Next, the constitution of the stapler and transversal aligner which are characteristic units of the present invention will be explained.
Generally, the stapling process includes binding of one corner of each sheet and binding of several places (for example, two places) along one edge of each sheet. Particularly in the case of binding several places, when a sheet bundle stapled is ejected, as shown in
The sheet post-processing apparatus of the present invention is characteristic in that such bulging due to overlaid stapling positions is reduced and sheet bundles are prevented from breaking of the stack.
On the other hand, stapler 14 is slidden in direction A1 along the edge of sheet P by stapler driver 49, is stopped at first stapling position al, and performs the stapling process. Next, stapler 14 is slidden in direction A1 by distance L1 along the edge of sheet P, is stopped at second stapling position a2, and performs the stapling process. In this way, stapler 14 is stopped at several places in the movement process and performs the stapling process.
When the stapling process at the first and second stapling positions is finished, as shown in
When first sheet bundle T stapled in this way is ejected, transversal aligning plates 47a and 47b, as shown in
Stapler 14 is at previous second stapling position a2 and performs the stapling process at stapling position a2. Next, stapler 14 moves in direction A2 along the edge of sheet P by distance L1, is stopped at first stapling position a1, and performs the stapling process. In this way, stapler 14 stops at several places in the movement process in the opposite direction and performs the stapling process.
When the stapling process is finished in this way, as shown in
In the aforementioned movement of stapler 14, distance L1 between the first stapling position and the second stapling position depends on the binding intervals of sheets, while movement distance L2 of transversal aligning plates 47a and 47b in the separation direction from the normal aligning position may be a distance that stapling positions ST of the first sheet bundle and second sheet bundle which are stapled are not overlaid each other, for example, a distance that the stapling positions are shifted by about 15 mm. When movement distance L2 is set, for example, to less than L1/2, the movement distance of transversal aligning plates 47a and 47b can be made smaller.
As mentioned above, stapler 14, at the normal aligning position, can perform the stapling process during the alternating motion from position al to a2 and from position a2 to a1, thus the movement distance of stapler 14 can be minimized. Therefore, the time in correspondence with the movement of stapler 14 can be reduced and the process can be performed at high speed. Further, after the stapling process, transversal aligning plates 47a and 47b convey sheet bundles alternately in directions A1 and A2.
Further, in the examples shown in
Namely, the sheet bundle stapled in
Further, in the example shown in
As mentioned above, in the embodiment of the present invention, sheets stapled and ejected, when stacked on sheet receiving tray 16 (or 18), can be prevented from breaking and pressing out. Therefore, a sheet post-processing apparatus convenient to a user can be obtained free of a lowering of the efficiency of the image forming apparatus.
In the embodiment aforementioned, the stapling positions of every sheet bundle are the same positions, and the sheet bundles are shifted from each other after the stapling process and are ejected to sheet receiving tray 16 (or 18). However, the present invention is not limited to it.
As shown in
Furthermore, as shown in
Further, as shown in
Further, the present invention is not limited to the above explanation and without being deviated from the claims, the present invention can be modified variously. For example, the examples that stapler 14 performs the stapling process at one place and two places are explained, though it can perform the stapling process at three places.
Claims
1. A sheet post-processing apparatus for stapling and ejecting sheets conveyed from an image forming apparatus, comprising:
- processing tray means for loading the sheets conveyed from the image forming apparatus;
- stapling means for stapling a sheet bundle of the sheets loaded on the processing tray means; and
- ejection means for leading the stapled sheet bundle to a sheet receiving tray and ejecting the same so as to shift the stapling positions of the plurality of sheet bundles loaded on the sheet receiving tray from each other at each upper and lower stages.
2. A sheet post-processing apparatus to staple and eject sheets conveyed from an image forming apparatus, comprising:
- a processing tray to load the sheets conveyed from the image forming apparatus;
- a stapler to staple a sheet bundle of the sheets loaded on the processing tray; and
- an ejection unit to leading the stapled sheet bundle to a sheet receiving tray and eject the same so as to shift the stapling positions of the sheet bundles loaded on the sheet receiving tray from each other at each upper and lower stages.
3. The apparatus according to claim 2 further comprising:
- an aligning unit including a pair of aligning plates to align the sheets loaded on the processing tray from both sides in the conveying direction to move the pair of aligning plates to a normal aligning position and a position shifted from the normal aligning position by a predetermined distance in a direction perpendicular to the conveying direction,
- wherein the stapler can move along edges in the conveying direction of the sheets aligned by the aligning unit and staple the conveyed sheets at several places at the normal aligning position, and
- the sheet ejection unit leads the sheet bundles stapled onto the sheet receiving tray in the state that the sheet bundles are shifted from each other in the direction perpendicular to the conveying direction by the aligning unit.
4. The apparatus according to claim 3, wherein:
- the aligning unit can move the pair of aligning plates to the normal aligning position and at a predetermined distance around the normal aligning position in a first direction perpendicular to the conveying direction and in a second direction opposite to the first direction, and
- the ejection unit leads the sheet bundles stapled at the normal aligning position onto the sheet receiving tray by shifting them alternately in the first direction and second direction.
5. The apparatus according to claim 3, wherein:
- the stapler, when the pair of aligning plates are at the normal aligning position, moves in the first direction, and at a first position and a second position in the movement direction, staples sheets conveyed, and
- moves next the stapler in the opposite direction of the first direction and at the second position and first position in the movement direction, staples sheets conveyed next.
6. The apparatus according to claim 3, wherein assuming an interval between stapling positions by the stapler as L1 and the predetermined distance of moving of the aligning unit from the normal aligning position as L2, L2<L1/2.
7. The apparatus according to claim 3, wherein positions stapled by the stapler are at least two places along the edges of the sheets.
8. The apparatus according to claim 3, wherein the aligning unit includes, in addition to the pair of aligning plates to align the sheets loaded on the processing tray from both sides in the conveying direction, second aligning unit to aligning the edges of the sheets in the conveying direction.
9. The apparatus according to claim 8, wherein the second aligning unit includes a stopper installed on the stapler to stop the edges of the sheets in the conveying direction.
10. The apparatus according to claim 2, wherein the stapler staples a first sheet bundle loaded on the processing tray at a first stapling position and staples a next second sheet bundle at a second stapling position shifted from the first stapling position, and the ejection unit ejects the first sheet bundle and second sheet bundle onto the sheet receiving tray.
11. The apparatus according to claim 10, wherein the first sheet bundle and second sheet bundle are stacked on the sheet receiving tray in the state that both sides thereof in the conveying direction are aligned.
12. The apparatus according to claim 10, wherein positions stapled by the stapler are at least two places along the edges of the sheets.
13. The apparatus according to claim 10, wherein a position stapled by the stapler is one place of a corner of each sheet.
14. A sheet post-processing method for stapling and ejecting sheets conveyed from an image forming apparatus, comprising:
- loading the sheets conveyed from the image forming apparatus on a processing tray;
- stapling a sheet bundle of the sheets loaded on the processing tray by a stapler; and
- leading the stapled sheet bundles to the sheet receiving tray and ejecting the same so as to shift the stapling positions of the sheet bundles loaded on the sheet receiving tray from each other at each upper and lower stages.
15. The sheet post-processing method according to claim 14 further comprising:
- aligning the sheets loaded on the processing tray from both sides in the conveying direction by a pair of aligning plates, wherein the pair of aligning plates moves to a normal aligning position and a position shifted from the normal aligning position by a predetermined distance in a direction perpendicular to the conveying direction;
- the stapler moves along edges in the conveying direction of the sheets aligned and staples every conveyed sheet at several places at the normal aligning position; and
- the sheet bundles stapled are led onto the sheet receiving tray in the state that they are shifted from each other in the direction perpendicular to the conveying direction.
16. The sheet post-processing method according to claim 15, wherein the pair of aligning plates are moved to the normal aligning position and at a predetermined distance around the normal aligning position in a first direction perpendicular to the conveying direction and in a second direction opposite to the first direction, and
- the sheet bundles stapled are moved onto the sheet receiving tray in the state that they are alternately shifted in the first direction and second direction.
17. The sheet post-processing method according to claim 15, wherein when the pair of aligning plates are at the normal aligning position, the stapler moves in the first direction and at a first position and a second position in the movement direction, staples sheets conveyed, and
- the stapler moves next in the opposite direction of the first direction and at the second position and first position in the movement direction, staples sheets conveyed next.
18. The sheet post-processing method according to claim 15, wherein assuming an interval between stapling positions by the stapler as L1 and the predetermined distance of moving from the normal aligning position as L2, L2<L1/2.
19. The sheet post-processing method according to claim 14, wherein the stapler performs the stapling process for a first sheet bundle loaded on the processing tray at a first stapling position and performs the stapling process for a next second sheet bundle at a second stapling position shifted from the first stapling position, and the first sheet bundle and second sheet bundle stapled are ejected onto the sheet receiving tray.
20. The sheet post-processing method according to claim 19, wherein the first sheet bundle and second sheet bundle are stacked on the sheet receiving tray in the state that both sides thereof in the conveying direction are aligned.
Type: Application
Filed: Dec 21, 2006
Publication Date: Jun 21, 2007
Applicant: TOSHIBA TEC KABUSHIKI KAISHA (Tokyo)
Inventors: Yasunobu Terao (Shinagawa-ku, Tokyo), Mikio Yamamoto (Shinagawa-ku, Tokyo), Yoshiaki Sugizaki (Shinagawa-ku, Tokyo), Hiroyuki Taki (Shinagawa-ku, Tokyo)
Application Number: 11/614,182
International Classification: B65H 37/04 (20060101);