JP2002193515A - Sheet post-processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently gather sheets recorded with images by each copy and bind them for discharging them at a high speed and prevent occurrence of wrinkles and flaws on a sheet bundle especially when the sheet bundles are discharged. SOLUTION: This device comprises a stacker for loading sheets and storing them temporarily, a binding means for binding sheet bundles loaded on the stacker, an discharging belt having a discharge claw protruded for conveying the bound sheet bundles, a paper discharging means for discharging the sheet bundles, and a paper discharging tray for storing the discharged sheet bundles. When a discharging linear velocity of the paper discharging means is higher than an extruding linear velocity of the sheet bundles by the discharging claw and the discharging claw rotates with making an arc locus in a conveying process to discharge sheet bundles with the minimum size, rear ends of the sheet bundles do not collide with the discharging claw.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet post-processing apparatus for automatically binding and discharging a recording sheet (sheet) on which an image is recorded by an image forming apparatus by a stapler, and more particularly, to a high-speed image forming apparatus. The present invention relates to a sheet post-processing apparatus capable of coping with the following.

[0002]

2. Description of the Related Art A sheet post-processing device called a finisher is used as a device for collating and stapling a plurality of image-recorded sheets discharged from an image forming apparatus for each number of copies by a stapler.

The finisher has a function connected to the image forming apparatus main body, and is driven in accordance with a sequence operation of a copy process.

[0004] Thus, for an image forming apparatus capable of processing the copying process at a high speed, high-speed processing possible finisher capable of performing the function following the its speed is required.

[0005] For such a high-speed processing of the possible finisher, already JP-A-60-142359, the same 6
Nos. 0-158463 and 62-239169, and JP-A Nos. 62-288002 and 63-267667.
The proposals in JP-A-2-27691 and JP-B-5-41991 are disclosed.

[0006]

One of the sheet post-processing apparatuses of the type in which a stapled sheet bundle is conveyed by discharge means and discharged to an external discharge tray is bound at one end. When the combined sheet bundle is conveyed on a discharge belt, and is further nipped and discharged by a pair of upper and lower discharge rollers, if the linear velocity of the conveyance belt and the linear velocity of the discharge rollers are the same, the discharge belt The gripping portion for pushing the rear end of the sheet protruding in the middle of the sheet rotates integrally with the rear end of the sheet, and competes with the rear end of the sheet when the gripping portion is separated from the rear end of the sheet. And cause scratches and tears at the rear end of the sheet.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to improve the above-mentioned problem. Accordingly, it is an object of the present invention to provide a sheet post-processing device (finisher) capable of smoothly discharging a sheet bundle.

[0008]

The object of the present invention is to provide a stacker for stacking and temporarily storing sheets carried out from an image forming apparatus, a binding means for aligning and binding a bundle of sheets stacked on the stacker, A discharge belt for projecting the stapled sheet bundle, a discharge belt protruding from a discharge claw, a discharge unit for nipping and discharging the sheet bundle conveyed by the discharge belt, and a sheet discharged from the discharge unit A discharge tray for storing a bundle, wherein the discharge linear velocity of the discharge means is higher than the linear velocity of pushing the sheet bundle by the discharge claw, and the conveying step of discharging a sheet bundle of a minimum size. The sheet post-processing apparatus is characterized in that the rear end portion of the sheet bundle is set so as not to collide with the discharge claw when the discharge claw rotates along an arc trajectory.

[0009]

Next, an embodiment of a sheet post-processing apparatus according to the present invention will be described with reference to the accompanying drawings.

FIG. 1 is an overall configuration diagram of a copying machine provided with a sheet post-processing apparatus. 100 is a copying machine main body, 200 is a paper feeding unit (PFU device), and 300 is a circulating automatic document feeder (RDH device). ), 400 denotes a sheet post-processing apparatus (finisher, hereinafter also referred to as FNS apparatus).

The copier body 100 includes a scanning exposure unit 110,
The image forming unit 120, the paper feeding unit 130, the transporting unit 140, the fixing unit 150, the paper discharge switching unit 160, the plurality of paper feeding cassettes 17
0 and double-sided recording sheet refeeding device (ADU device) 1
80.

In the drawing, a dashed line indicates a conveying path of the sheet P. After the sheet P accommodated in the sheet feeding cassette 170 or the sheet feeding unit (PFU device) 200 at the lower portion of the copying machine main body 100 is subjected to image formation by the image forming unit 120,
After the main route accommodated in the FNS device 400 via the conveyance unit 140, the fixing unit 150, and the paper discharge switching unit 160, and the sheet P branched from the paper discharge switching unit 160 is temporarily stocked in the ADU device 180, And a circulation route which is re-fed and reaches the paper feeding section 130 of the copying machine main body 100.

The document D loaded on the document mounting table of the RDH apparatus 300 starts to be fed by the operation of a copy button on the operation panel of the copying machine main body 100, passes through the feeding section 301, and is conveyed by the transport belt 302. It is conveyed on the platen glass 111 and set at the exposure position.

The document D is read by receiving the exposure scan of the document image by the operation of the operation exposure unit 110, and after the reading is completed, the transport belt 302 rotates again and is fed.
The originals are stored in the lowermost layer of the original bundle on the original mounting table via the reverse paper discharge path 303.

Although the circulation feeding of the document D has been described above, the RDH device 300 is an automatic document feeding device (AD).
F), the original D having finished reading the image goes straight ahead and passes through the discharge tray 3 via a discharge roller.
04, and are stacked.

A copy image of the original D obtained by the exposure scanning is recorded on a sheet P fed from the sheet feed cassette 170 or the PFU device 200 through an image processing process of the copying machine main body 100.

The sheet P on which an image has been recorded is the ADU
The sheet is once fed to the apparatus 180, turned upside down, discharged from the sheet discharge switching section 160 with the image side facing down, and fed to the FNS apparatus 400 of the present invention.

FIG. 2 is a sectional view showing the structure of the FNS apparatus 400. The FNS apparatus 400 is installed with its position and height adjusted so that the sheet P receiving roller 401 coincides with the paper discharge port of the copier main body 100.
Is connected to the control system so as to be driven in accordance with the operation of.

The conveying path of the sheet P connected behind the receiving roller 401 is an upper offset conveying path 410.
(First transport path), a second transport path 420 in the middle stage and a third transport path 430 in the lower stage, and the sheet P is selected by selecting an angle occupied by the switching gates G1 and G2.
Is fed to one of the transport paths. U1
Is a first unit constituting the first transport path, and U2 is a second unit.
The second unit U3 constituting the transport path is a third unit constituting the third transport path.

The second transport path 420 and the third transport path 430 have guide belts 422 and 432 at each end on the downstream side of the transport, and feed the rear end of the sheet P to the stapler. At positions facing the guide belts 422 and 432, discharge belts 425 and 435 having discharge claws 424 and 434, respectively, and the discharge belts 4
A first stacker 426 and a second stacker 436 are respectively installed at predetermined inclination angles at positions sandwiching 25 and 435. Of the three rollers for winding the guide belts 422 and 432, the lowermost roller is the impeller 42
8, 438, when the sheet P switches back, the sliding contact of the impellers 428, 438 may be used to reliably contact the stoppers 441, 451.

Further, the first stacker 426 and the second stacker 436 have first
A stapler ST1 and a second stapler ST2 are arranged.

[0022] In the sheet conveying downstream of the first stacker 426, in the vicinity sheet discharge unit of the FNS apparatus 400, first paper discharging section 460 formed of a pair of upper and lower discharge rollers is provided. Similarly, a second sheet discharging means 470 is provided downstream of the second stacker 436.

Further, on the right side of the FNS device 400,
Discharge tray elevating means 480 is provided. The discharge tray elevating means 480 is provided with a pair of support members 482 before and after engaging with the plurality of guide rollers 481 and moving up and down. The support member 482 includes a first discharge tray T1 and a second support member 482. The paper discharge trays T2 are individually nipped and moved up and down.

[0024] The pair of support members 482 is fixed to the lifting wire 484 was stretched between the separate dedicated motor M1, M2 and the pulley 483, the motor M1, the first discharge of the rotation of the M2 tray T1 And the second discharge tray T
2 are individually translated in the vertical direction.

The control circuit built in the copying machine main body 100 is composed of a basic circuit as shown in FIG. 3, and prior to the start of a copy operation, a paper discharge mode (staple mode or non-sort mode) is selected, and The number of copies and the number of copies are set.

When the mode is set to the non-sort mode in which the binding is unnecessary or the offset mode for shifting and aligning, the switching gates G1 and G2 are kept in the initial state, the sheet P advances straight, and the receiving roller 401 and the intermediate roller 402 The sheet is discharged out of the apparatus via a first transfer path (offset transfer path) 410 including a transfer belt 403 and a transfer roller 404, and is placed and stored on an upper first discharge tray T1.

When the offset mode is selected as the discharge mode, the switching gates G1 and G2 feed the sheet P upward, feed the sheet P to the first transfer path 410, and feed the sheet P to the transfer belt 403 and the discharge belt 403. First through the roller 404
The sheet is discharged onto the discharge tray T1.

A pair of discharge rollers 404 comprising a drive roller and a driven roller are provided with an offset drive section which can reciprocate in the direction perpendicular to the drawing, and shift-drive after detecting the rear end passage of the discharged sheet P. Then, the sheets P are stacked in a zigzag manner in the left-right direction with respect to the discharged sheets according to the number of copies so that the sheets P can be easily sorted.

When the binding mode is selected as the paper discharging mode, the switching gate G2 rotates, and the sheet P fed by the receiving roller 401 goes straight and is fed to the second conveying path 420. The sheet P is once pushed up and placed on the first stacker 426 via the guide belt 422 in the second unit U2. At this time, the rear end of the sheet P is caused by the rotation of the guide belt 422 and the weight of the sheet P. The first stapler ST1 slides down on the first stacker 426, and the binding portion (the stopper 441 of the sheet transfer portion 440) of the first stapler ST1.
It is guided to.

The first sheet P corresponding to the number of originals D
After the last sheet is detected by the sensor S1, the switching gate G1 is rotated, and the second sheet P is fed downward and fed to the third conveyance path 430, and guided as described above. By the action of the belt 432, the push-up and placement on the second stacker 436 is started. The transfer unit 450 of the third unit U3 is connected to the sheet transfer unit 44 of the second unit U2.
It has the same structure as 0.

On the other hand, during the feeding of the second sheet P,
The sheets P of the first set after the stacking are stapled by the operation of the first stapler ST1 and then pushed back on the first stacker 426 by the push-back operation of the transfer lever 442 at a predetermined position against gravity. Pushed up and held.

FIG. 4 is a front view of the sheet discharge section. FIG.
5A is a plan view of the sheet discharge unit, and FIG. 5B is a cross-sectional view taken along line AA.

The transfer lever 442 of the sheet transfer section 440 reciprocates only when the bound sheet bundle is discharged.

The first discharge belt 425 is connected to the motor M3.
Drives the gears Z1 and Z2 and the timing belt TB1
, The rear end face of the sheet P is pushed up by the ejection claw 424, and the sheet P of the first set stapled while stopping after making one revolution is stopped by the first ejection. The sheet is discharged onto the paper tray T1.

In the meantime, the lamination of the second sheet P is completed, and the switching gate G2 is returned again.
The binding of the second sheet P is performed by the operation of the second stapler ST2, and the binding is performed by the protrusion of the stopper 451 and the rotation of the second discharge belt 435, as described above.
The sheet P of the set is discharged onto the second discharge tray T2.

As described above, according to the FNS apparatus 400 of the present invention, a plurality of sheets P on which images have been recorded can be collated and bound at two places in parallel without any particular time lag. Post-processing of P will be performed quickly.

The motor M3 is operated in accordance with the discharge amount of the sheets P, and the first and second discharge trays T1 and T2 are lowered by the number corresponding to the number of sheets to be processed, so that the sheets P can be discharged. .

The above-mentioned first and second staplers S
T1 and ST2 are both the first and second stackers 42.
By providing the 6 and respective drawings front of 436, the upper left 1 but places the can bound together by staples, if the additional installation of the stapler also to the back side of the drawing two positions when discharged by the sheet P every portrait Can be stapled, and when the sheet P is placed in a landscape orientation and discharged, the upper left portion can be stapled.

The position of the sheet P discharged onto the stackers 426 and 436 moves in parallel via the reference surface (rising surface) 426A integrated with the stacker 426 and the engagement of the pinion 427A and the rack 427B by the operation of the motor M2. Alignment means 427 comprising a sliding member 427C to be moved
And is regulated by.

When a large number of sheets P are discharged onto the stacker 426 (436) and are conveyed at high speed, the bundle of sheets P gradually stacked on the stacker 426 (436) increases rapidly and becomes thicker. Thus, the final sheet P does not drop by its own weight without fail along the upper surface of the inclined sheet bundle, stops halfway, and the rear end of the sheet P is
In some cases, stapling may not be performed correctly without contacting 1). When the number of stapleable sheet bundles is 50,
The irregularity of the sheets P tends to occur after about the 25th sheet. Hereinafter, the aligning process for surely aligning even a thick sheet bundle of 25 sheets or more and enabling accurate binding will be described with reference to FIG. The number of copies to be copied and the set value (N1) of the number of sheets for each copy are transmitted from the copying machine body by communication. Stacker 426 (436) of sheet post-processing apparatus 400
The number of sheets P passing therethrough is sequentially counted by a sensor S42 (S43) provided near the entrance (N2). The sheet P is conveyed onto the stacker 426 (436),
It slides down the inclined surface, comes into contact with the stopper 441 (451), and stops. At this stop position, the slide member (movable alignment plate) 427C of the alignment means 427 moves toward the side edge of the sheet P from a position about 20 mm away from the outside in the width direction of the sheet P, and moves the sheet P. The sheet P is pressed against the reference surface 426A, and is further moved to a position about 3 mm inward from the width of the sheet P, and is reversed to return to the original position. Each time the sheet P is conveyed one by one onto the stacker 426 (436), the movable alignment plate 427C makes one reciprocation to perform the paper alignment operation. When the subsequent sheet P slides down on the stacker 426 (436), the preceding sheet P slides down to the stopper 441 (451) side due to its own weight and sliding contact of the subsequent sheet P. The number of sheets P conveyed onto the stacker 426 (436) is counted by the sensor S42 (S43).
When it is detected that the set value N1 has been matched (N2 = N1), the sheet bundle obtained by stacking the final sheet P is
After the movable alignment plate 427C makes one reciprocal movement by the paper alignment operation, it moves to the side end of the sheet bundle again,
The sheet bundle side end is pressed (final alignment operation). In the sheet bundle pressing state, a paper pressing lever 443 described later is raised to press the rear end of the sheet bundle, and the stapling operation is performed. When the number of sheets N2 is 25 or less, the above-described paper alignment operation for each sheet and the final alignment operation after the final sheet is stopped are performed. When the number of sheets N2 is 25 or more, the above-described paper alignment operation is performed, and the last sheet P is stacked in the stacker 426.
(436) After being placed on the upper sheet bundle, the final alignment operation is performed about 1 second later, and the paper holding lever 443 is raised and the stapling operation is performed with the side edges of the sheet bundle pressed. This When loading a large number of sheets of more than 25 sheets on the stacker 426 (436), the final paper will be stopped without contact the stopper. On the contrary,
By leaving a margin of about one second after paper alignment for the final alignment operation, the final sheet P is
And slides down on its own weight, and it stops proceeds toward the stopper 441 (451). In this way, the final sheet P can slide down reliably to the predetermined stop position. Particularly when the sheet is conveyed at a high speed, the result of the sheet alignment is large. The margin time of about 1 second is not limited to this, and the sheet conveyance speed, the surface friction of the sheet,
It varies depending on the mass of the sheet, the inclination angle of the stacker 426 (436), and the like, and the optimum margin time is determined by these setting conditions.

Further, each of the above staplers ST1, ST
2. Stackers 426, 436, discharge belts 425, 43
5 and the like are supported by each substrate of the second unit U2 and the third unit U3, and a pair of guide rails R provided respectively.
1 and R2, the FNS device 400 can be attached to and detached from the FNS device 400. If the front side of the device can be opened by a door, the stapler and the like can be removed in a unit state. And maintenance such as jam clearance can be easily performed.

FIG. 6 is a perspective view of the stapler ST1 and the sheet transfer section 440. The transfer unit and the stapler ST provided at the end of the upper second conveyance path 420
Since the transfer unit 1 and the stapler ST2 provided at the end of the lower third conveyance path 430 have the same structure, the common structure will be described below.

The sheet transfer section 440 and the stapler ST1 are integral with each other, can slide on a slide rail (not shown) and can move in a direction orthogonal to the sheet conveying direction, and is stretched between a driving pulley and a driven pulley. It is fixed to a part of a rotatable timing belt and is connected to a stepping motor M4 as a driving source via a gear train.
Then, the sheet transfer section 440 and the stapler ST1
Is controlled by the stepping motor M4.

The sheet transfer section 440 is connected to the second transport path 4
20, slides on the first discharge belt 425 and the first stacker 426 by the guide belt 422, ascends, and temporarily stops the trailing end of the sheet P which has been lowered after discharge, and stops at this stop position. After the alignment process (stapling process), the sheet is sent out again and the discharge belt 42 is
5 is a mechanism for sending out by the discharge claw 424 of FIG.

The sheet delivery unit 440, the sheet P
Abutment reference stopper 4 that abuts and aligns the rear end of
41, a pair of movable left and right transfer levers 442 for sending the sheet P to the discharge belt 425 side, and a pair of movable left and right paper press levers 443 for holding the sheet P during stapling.

The driving of the motor M4 raises the paper pressing lever 443 to press and hold the sheet bundle. Next, a stapling operation is performed. Then, the delivery lever 442
Is moved diagonally rightward in the figure. This transfer lever 44
2, the abutment surface portion 44 of the transfer lever 442
2A pushes the rear end of the sheet P and sends it to the discharge belt 425 side.

FIG. 7 is a sectional view of the sheet discharging means 460. The sheet bundle P placed on the discharge belt 425 obliquely ascends on the rotating discharge belt 425 and the surface of the stacker 426 while the rear end portion of the sheet is held by the discharge claw 424, and the sheet bundle P The leading end of P is a sheet discharging means 460
And then placed on the first tray T1.

The paper discharging means 460 includes a driving source (motor M5).
Roller 461 and upper roller 46 that are connected to
2 and an arm 46 for swingably supporting the upper roller 462
3, support shaft 464 for supporting the swingable arm 463
A spring 465 for urging the arm 463 with a spring; and a guide plate 4 for sheet introduction provided near the peripheral surface of the lower roller 461.
26. The lower roller 461 is FN
The S device 400 is rotatably supported at a predetermined position of the frame. The upper roller 462 is in pressure contact with the lower roller 461 by its own weight and a predetermined urging force of the spring 465.
468 is a sheet introduction F fixed near the lower roller 461.
It is a guide plate. The lower surface of the arm 463 also serves as an upper guide plate 463A for introducing a sheet.

The paper discharge means 470 at the most downstream of the third transport path 430 has substantially the same structure as the paper discharge means 460.

FIG. 8 is a plan view showing a driving system of the sheet discharging means 460, and FIG. 9 is a configuration diagram of the driving system.

Gear Z1 fixed to the drive shaft of motor M5
Is the gear Z2 provided on the intermediate shaft, the timing pulley TP1
And is branched into two systems.

The lower branch causes the timing belt TB1 to rotate the timing pulley TP2. A drive shaft 428A and a drive roller 428B are provided coaxially with the timing pulley TP2 via a coupling 466, and a discharge belt 425 is provided together with the other driven roller 428C.
Is rotated.

The upper branch includes a timing pulley TP3 and a gear Z3 provided on an intermediate shaft by a timing belt TB2.
Is further branched into upper and lower systems. Branch of downward,
The lower roller shaft 461A coaxially integrated with the gear Z5 is rotated via the gears Z3, Z4, Z5. The upper branch includes gears Z3, Z6, Z7 and timing pulleys TP4, T
P5, the gear Z through the timing belt TB3.
8, and the upper roller shaft 462A, which is coaxially integrated with the gear Z9, is rotated.

The gear Z7 and the timing pulley TP4 are integrally provided at the shaft end of the support shaft 464, and the timing pulley TP5 and the gear are mounted on an arm 463 swingable about the support shaft 464. Z8 and an upper roller shaft 4 having a gear Z9 meshing with the gear Z8.
62A are disposed. Therefore, the upper roller shaft 462A
Is both swing transmission system around the support shaft 464.

As described above, in the sheet post-processing apparatus of the present invention, the lower roller 461 and the upper roller 462 having the main conveying force are driven and rotated by the motor M5 of the driving source for driving the discharge belt 425, and the driving is performed. The rotated upper roller 462 can swing about a support shaft 464. The sheet bundle P extruded on the discharge belt 425 by the discharge claw 424 slides on the first stacker 425, and further passes through the lower guide plate 468. The arm 46 which reaches the nip portion 461 and has an upper guide plate 463A
3 and the upper roller 462, and lift the upper roller 46.
2 and the lower roller 461, are conveyed, and are placed on the first discharge tray T <b> 1.

FIG. 10 is a sectional view showing the process of discharging the sheet bundle P. FIG. 10A illustrates a rear end portion P of the sheet bundle P.
_B is conveyed being pushed by the ejection claw 424, upper roller 462 of the tip P _A of the sheet bundle P is discharge means 460
And a state in which the lower roller 461 is nipped by a nip portion.

In the driving system of the sheet post-processing apparatus of the present invention,
The linear velocity of the discharge belt 425, that is, the ratio (V1: V2) of the linear velocity V1 of pushing the sheet bundle P by the discharge claws 424 to the linear velocity V2 of the lower roller 461 is (1: 1.1) to (1: 1.1).
(1: 1.4). For example, the linear velocity V2 of the lower roller 461 was set to 692 mm / s while the linear velocity V1 of the discharge belt 425 was set to 550 mm / s.
Thus the linear velocity V2 of the sheet discharging downstream, by setting slightly faster than the linear speed V1 of the ejection claw 424 on the upstream side, to the tip P _A of the sheet bundle P is applied to the nip portion, FIG. 10 As shown in (A), the sheet is conveyed at the linear velocity V1 of the discharge claw 424. And after the tip P _A of the sheet bundle P is nipped by the nip pressure between the lower roller 461 and the upper roller 462, the sheet bundle P is conveyed by the slightly faster by the linear velocity V2. Therefore, the rear end P of the sheet bundle P
_B gradually separates from the pushing surface of the ejection claw 424. Further, at the time shown in FIG. 10B, when the conveyance of the sheet bundle P further proceeds and the discharge claw 424 starts to rotate along the peripheral surface of the drive roller 428B in a circular path R, the sheet bundle P
The rear end portion P _B, so as not to interfere escaped out of range of the circular path R, is set the linear velocity difference. That is, the linear velocities V1 and V2 are set to the minimum size, for example, B5
When the sheet bundle P having a medium size is conveyed, the discharge claw 4
When 24 rotates in an arc trajectory R, so that the trailing end P _B of the sheet bundle P does not collide with the ejection claw 424, the rear end P _B
And the discharge claw 424 are separated from each other.

In this embodiment, an example is shown in which the apparatus is connected to a copying apparatus. However, the present invention can be used in connection with an image forming apparatus such as a printer or a facsimile, or a light printing machine.

[0059]

According to the present invention, a plurality of thick sheet bundles can be efficiently and smoothly collated and bound for each copy at high speed, and wrinkles and scratches are generated on the sheet bundle particularly when the sheet bundle is discharged. And a sheet post-processing apparatus without the above.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a copier including a sheet post-processing apparatus of the present invention.

FIG. 2 is a sectional view of a sheet post-processing apparatus.

FIG. 3 is a block diagram showing the basics of a control system.

FIG. 4 is a front view of a sheet discharge unit.

5A and 5B are a plan view and a cross-sectional view taken along line AA of a sheet discharge unit.

FIG. 6 is a perspective view of a stapler and a sheet transfer unit.

FIG. 7 is a cross-sectional view of a sheet discharging unit.

FIG. 8 is a plan view showing a driving system of a paper discharging unit.

FIG. 9 is a configuration diagram of a drive system of a paper discharging unit.

FIG. 10 is a cross-sectional view illustrating a sheet bundle discharging process.

[Explanation of symbols]

100 Copier body 400 Sheet post-processing device (FNS device, finisher) 420 (430) Second (third) transport path 422, 432 Guide belt 424, 434 Discharge claw 425 (435) First (second) discharge belt 426 (436) First (second) stacker 440 Sheet transfer section 441 Stopper 442 Transfer lever 443 Paper holding lever 460, 470 Discharge means 461 Lower roller 462 Upper roller 463 Arm 464 Support shaft 465 Spring 468 Lower guide plate 480 Discharge tray lifting means G1, G2 switching gate M1, M2, M3, M4, M5 motor P sheet (recording paper), sheet bundle ST1 first stapler (stitching means) ST2 second stapler (stitching means) T1 first discharge tray (upper Tray) T2 2nd output tray (lower tray) V1 , V2, V3 linear velocity

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H072 AB09 CA01 CA04 CA05 GA08 JA02 JA03 3F049 AA01 CA00 DA12 DB02 EA13 LA01 LB01 3F054 AA01 AB01 AC01 BA04 BB01 BJ03 DA01 3F108 GA01 GB01 HA02 HA32

Claims (1)

[Claims] A stacker for stacking and temporarily storing sheets conveyed from the image forming apparatus; a binding unit for aligning and binding the sheet bundle stacked on the stacker; A discharge belt that conveys the paper, a discharge belt protruding from the discharge claws, a paper discharge unit that sandwiches and discharges the sheet bundle conveyed by the discharge belt, and a paper discharge tray that stores the sheet bundle discharged from the paper discharge unit. The discharge linear velocity of the paper discharge means is higher than the linear velocity of pushing the sheet bundle by the discharge pawl, and the discharge pawl moves along an arc trajectory in the conveying process of discharging the sheet bundle of the minimum size. A sheet post-processing apparatus, wherein a rear end portion of a sheet bundle is set so as not to collide with a discharge claw when drawing and rotating.