JP2000355455A - Paper sheet after treating device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper sheet after treating device equipped with a paper discharging means having the improved paper sheet aligning performance of a paper discharge device mounted on a paper sheet after treating device, and a simple mechanism. SOLUTION: In a paper sheet after treating device where a image formed paper sheet is carried by a carrying means for a paper sheet after treating device, and then is loaded on an intermediate stacker 31 to be after-treated by an after treating means, and after that, is discharged by a paper discharging means to be placed on a paper discharge bowl; the paper discharging means has a paper discharging roller, composed of paper discharging upper and lower rollers 21 and 22 for nipping, carrying, and discharging the paper sheet and rotatable normally and inversely, a crimping means 23 for oscillating the roller 21 to pressedly contact with and separate from the roller 22, and a driving means having the drive source of a single drive motor M1 for driving the rollers 21 and 22 and the means 23 and rotatable in normally and inversely.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrophotographic copying machine,
The present invention relates to a sheet post-processing apparatus and an image forming apparatus that discharge an image-formed sheet discharged from an image forming apparatus main body such as a printer or a facsimile by a sheet discharging unit and place the sheet on a sheet discharge tray.

[0002]

2. Description of the Related Art A sheet post-processing device is used as a device for collating and binding a plurality of image-recorded sheets discharged from an image forming apparatus body by a number of copies by a binding means. Further, the sheet post-processing apparatus includes a shift sorting process, a collating process, a punching process,
Some have functions such as bookbinding.

The paper post-processing apparatus is connected to a main body of an image forming apparatus such as a copying machine, a printer, a facsimile or the like, and is driven in accordance with a sequence operation of a copy or print process.

[0004] The sheet post-processing device performs sheet post-processing such as binding processing, shift sorting, and collation on the received sheets, and then discharges the sheets onto a sheet discharge tray.

The paper post-processing apparatus has already been disclosed in JP-A-60-142359 and JP-A-60-158463.
No. 62-239169, No. 62-288002
No. 63-267667, JP-A-2-276691
JP-A-8-319054 and JP-B-5-41991 disclose a configuration in which various sheets are conveyed to a post-processing unit and brought into contact with a stopping means.

[0006]

The image-formed paper conveyed into the paper post-processing apparatus is conveyed by the conveying means, and then conveyed backward and conveyed onto the intermediate stacker, where the rear end of the paper is conveyed. It is stopped at a predetermined position by contacting the stopping means. A plurality of sheets are sequentially conveyed and stacked at this stop position, and the rear end is aligned. After the post-processing such as the binding processing is performed on the rear-aligned sheet bundle, the sheet bundle is discharged to a discharge tray outside the apparatus by a discharge unit.

The following mechanism is known as a paper discharging means of such a paper post-processing apparatus.

(1) A sheet post-processing apparatus that conveys a sheet to a post-processing section by a winding ring, abuts a stop means, and lowers a sheet discharging roller only at the time of sheet discharging to discharge a sheet bundle.

(2) The intermediate stacker is set at a steep inclination angle, the paper is conveyed to the post-processing section by free fall of the paper, brought into contact with the stopping means, and the paper discharge roller is moved up and down using the engaging mechanism. And a sheet discharging means for discharging a sheet bundle by applying a pressing force to a sheet discharging roller using a solenoid.

(3) An automatic vertical force variable device is provided in the paper discharging means to obtain a higher gripping force when discharging a sheet bundle in which a plurality of sheets are bound than when discharging one sheet. Paper post-processing device for applying normal force
23 publication).

In any of the above-mentioned paper post-processing apparatuses, it is difficult to stabilize the paper transportability for paper of all characteristics, and there is a possibility that the paper may be curled or affected by static electricity. There is also a problem that the mechanism is complicated and the production cost is high.

The present invention solves the above-mentioned problems in a conventional sheet post-processing apparatus, improves sheet alignment performance, and provides a sheet post-processing apparatus and an image forming apparatus provided with a sheet discharging means having a simple mechanism. It is intended to do so.

[0013]

A sheet post-processing apparatus for achieving the above object transports an image-formed sheet by a conveying means of the sheet post-processing apparatus, and then stacks the sheet on an intermediate stacker.
In a paper post-processing device that is post-processed by post-processing means and then discharged by a paper discharging means and placed on a paper discharge tray, the paper discharging means is capable of rotating forward and reverse to convey, discharge, and hold a sheet. A discharge roller comprising an upper discharge roller and a lower discharge roller; a pressurizing means for swinging the upper discharge roller so as to be able to press and separate from the lower discharge roller; and a discharge upper roller and a lower discharge roller And a drive unit that uses a drive motor that can be rotated forward and backward to drive the pressure bonding unit and the pressing unit (claim 1).

According to a seventh aspect of the present invention, there is provided an image forming apparatus including the sheet post-processing device.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of an image forming apparatus having a sheet post-processing apparatus provided with a sheet discharging means according to the present invention will be described with reference to the accompanying drawings.

FIG. 1 is an overall configuration diagram of an image forming apparatus 1 equipped with a sheet post-processing device FS, an automatic document feeder DF, and an image reading device (scanner) SC.

The illustrated image forming apparatus main body 1A includes an image processing section 2, an image writing section 3, an image forming section 4, a high voltage power supply section 5, a cassette sheet feeding section 6, a fixing device 7, a sheet discharging section 8, an automatic duplex copy. A transport unit (ADU) 9 is provided.

An image reading device SC and an automatic document feeder DF are mounted on the upper portion of the main body 1A of the image forming apparatus. A sheet post-processing device FS is connected to the upper left side of the image forming apparatus main body 1A on the side of the paper discharge unit 8 in the drawing.

The document d placed on the document table of the automatic document feeder DF is transported in the direction of the arrow and is read by the image reading device SC.
The image on one side or both sides of the original is read by the optical system of (1), and is read by the CCD image sensor C1.

The analog signal photoelectrically converted by the CCD image sensor C1 is subjected to analog processing, A / D conversion, shading correction, image compression processing and the like in the image processing section 2, and then sent to the image writing section 3. .

In the image writing section 3, the output light from the semiconductor laser is applied to the photosensitive drum 4A of the image forming section 4 to form a latent image. In the image forming unit 4, processes such as charging, exposure, development, transfer, separation, and cleaning are performed, and an image is transferred to the sheet S transported from the cassette sheet feeding unit 6. The sheet S carrying the image is fixed by the fixing device 7 and sent from the sheet discharge unit 8 to the sheet post-processing device FS. Alternatively, the single-sided image-processed sheet S sent to the automatic double-sided copy conveyance section 9 by the conveyance path switching plate 8A is subjected to double-sided image processing in the image forming section 4 again, and then from the sheet discharge section 8 to the sheet post-processing apparatus FS. Sent in.

The sheet post-processing device FS is detachably mounted on the upper left portion of the main body 1A of the image forming apparatus. The sheet post-processing device FS includes a sheet transporting unit 10, a sheet discharging unit 20, a sheet post-processing unit 30, and an elevating sheet discharging unit 40.

In FIG. 1, on the right side of the image forming apparatus main body 1A, a cassette sheet feeding section 6 is provided below the image forming section 4 in the height direction of the apparatus main body, and a fixing device 7 is provided above the image forming section 4. A paper section 8 is provided. With this vertical arrangement, a paper transport path in a substantially vertical direction is formed. The sheet S sent from the cassette sheet feeding section 6 is conveyed along the vertically upper sheet conveying path and discharged outside the apparatus main body.

A paper transport path by the automatic double-sided copy transport section 9 is formed substantially parallel to the vertical paper transport path.

By forming the above-described vertical paper transport path, a shortest distance paper transport path from the cassette paper feed unit 6 to the paper discharge unit 8 is formed.

The sheet conveying means 10 of the sheet post-processing apparatus FS is accommodated in the space above the image forming apparatus main body 1A as shown. The paper inlet 11 of the paper transporting means 10 is connected to the paper discharge roller 8B of the paper discharge part 8 of the image forming apparatus main body 1A. In this mounted state, the sheet discharging means 20 and the sheet post-processing means 30 of the sheet post-processing apparatus FS are accommodated in the upper left space of the image forming apparatus main body in the drawing. The elevating sheet discharging means 40 including a plurality of sheet discharging trays 41 and the elevating driving means 42 is located on the side of the apparatus main body.

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

In FIG. 2, the sheet post-processing device FS includes a sheet conveying means 10, a sheet discharging means 20, a sheet post-processing means 30,
It is composed of elevating and discharging means 40, is unitized, is detachable from the apparatus main body, and can be pulled out toward the front side of the drawing by moving means such as a guide rail.

The paper transport means 10 is connected to a paper inlet 11 facing the paper discharge roller 8B of the paper discharge section 8 and guides the discharged paper S to the paper discharge means 20 (hereinafter referred to as a guide). A transport roller 1 composed of a driving roller and a driven roller for nipping and transporting the sheet S;
4, 15, and 16. The paper path formed by the guide plates 12, 13 and the transport rollers 14, 15, 16 forms a substantially horizontal transport path. Each drive roller of the transport rollers 14, 15, 16 is rotated forward by a drive motor (not shown).

The paper discharging means 20 comprises a paper discharging upper roller 21, a paper discharging lower roller 22, and a pressure bonding means 23 which are connected to a driving source and rotate forward and backward. The upper discharge roller 21 is moved up and down by a torque limiter, and presses the lower discharge roller 22 by a pressing unit 23.

The sheet post-processing means 30 includes
Intermediate stacker 31 for stacking a plurality of sheets S transported by the printer, width aligning means 32 for aligning and regulating the width direction of the sheets S stacked on the intermediate stacker 31, intermediate stacker 31
Stopping means 33 for abutting the leading end of the paper S stacked thereon in the traveling direction to position the paper S in the transport direction, and the staple S
A binding unit (stapler) 34 for driving P into a sheet bundle, and a moving unit 35 for moving and rotating the binding unit 34 to a predetermined position.

The elevating / discharging means 40 comprises a plurality of inclined discharge trays (also referred to as bins) 41 and an elevating drive means 42 for raising and lowering the discharge tray 41 in the vertical direction.

Although the illustrated sheet post-processing apparatus FS has a four-stage paper discharge tray 41, since there is a space below and above the elevating paper discharge means 40, the number of bins is increased. A processing device (for example, a paper post-processing device for 10 to 20 bins) FS can also be mounted. Further, the sheet post-processing device FS can also have a function of sorting sheets such as a mailbox.

FIG. 3 is a schematic diagram showing a process of transporting and discharging the sheet S in the sheet post-processing device FS.

(1) Paper discharge (paper transport path, FIG. 3
(See (a).) The image-formed sheet S discharged from the paper discharge roller 8B of the paper discharge unit 8 of the image forming apparatus 1 is introduced into the paper entrance 11 of the paper conveying means 10 of the paper post-processing apparatus FS. Information board 1
Transport rollers 14, 1 that pass through the transport path in 2 and rotate forward
5 is conveyed while being nipped by the transport roller 16 that rotates in the forward direction.

The leading end of the paper S passes through the paper discharge upper roller 21 and the lower paper discharge roller 22 which are rotated forward and are pressed and pinched, and the inclined surface of the paper discharge tray 41 of the lifting / lowering paper discharge means 40. It rises along. When the rear end of the sheet S passes through the nipping position of the transport roller 16, the rear end of the sheet S descends by its own weight and comes into contact with the inclined surface of the intermediate stacker 31.

(2) Reverse feeding and discharging before sheet post-processing (sheet conveying path, see FIG. 3B) The sensor PS1 provided near the conveying roller 15
After detecting the passage of the rear end portion, a predetermined time is measured by a timer, and then the upper discharge roller 21 is driven in reverse rotation to descend,
Press against paper. The lower discharge roller 22 driven by the same driving source stops driving by the clutch and is driven to rotate by the upper discharge roller 21. The upper discharge roller 21 is
It is made of a flexible foam such as a sponge roller, and is lightly pressed against the sheet S on the discharge lower roller 22.

By switching the reverse rotation of the upper discharge roller 21, the paper S lightly pressed against the reverse upper discharge roller 21 and the lower discharge roller 22 stopped at the nipping position,
The sheet S is conveyed obliquely downward on the intermediate stacker 31, and the rear end of the sheet S abuts against the stopping means 33, and the conveyance is stopped.

A pair of width aligning means 32 movably provided on both side surfaces of the intermediate stacker 31 can move in a direction orthogonal to the paper transport direction, and when the paper S is transported on the intermediate stacker 31 is received. When the sheet S is opened wider than the sheet width and is conveyed on the intermediate stacker 31 and stops by contacting the stop means 33, the side edge of the sheet S in the width direction is lightly hit to align the width of the sheet bundle.

Similarly, the succeeding sheet S also has a sheet transport path,
, And sequentially stacked on the upper surface of the preceding sheet S on the intermediate stacker 31, each time the width is adjusted and the stopping means 33
Stop in contact with.

After the rear ends of all the sheets S for one book abut against the stopping means 33, the staples SP are driven into the sheet bundle by the binding means 34 to form a booklet.

(3) Discharge after Paper Post-Processing (Paper Conveying Path, See FIG. 3C) When the binding process is completed, the stopped upper discharge roller 21
Is switched to forward rotation, and the lower discharge roller 22 and the upper discharge roller 21 switched to strong pressure contact by the pressing means 23
The sheet bundle nipped between is transported obliquely upward and stored in the sheet discharge tray 41.

FIG. 4 is a plan view of a main part of the paper discharging means 20, and FIG. 5 is a front view of the paper discharging means.

The drive motor M1 which can be rotated forward and backward is rotated by a rotation shaft 231 of the crimping means 23 via a timing belt TB1.
To rotate. The swing member 232 fixed to the rotation shaft 231 is held so as to be swingable about the rotation shaft 231. 233 is a torque limiter provided on the rotating shaft 231, and 234 is a pressing force adjusting spring for adjusting the pressing force of the swing member 232.

A groove 232A is provided at the tip of the swinging member 232.
Are drilled. The upper discharge roller 2 is provided in the groove 232A.
One rotating shaft 211 is loosely fitted and movably supported.

The rotary shaft 211 has two hard rollers 21
2 is rotatably supported, and the sponge roller 213 is fixed.

A pulley fixed to one shaft end of the rotating shaft 211 and a pulley fixed to the rotating shaft 231 have:
A timing belt TB2 is erected. Rotating shaft 23
By the forward / reverse rotation of 1, the rotation shaft 211 rotates forward / reverse via the timing belt TB2.

The distal ends of the two pressing springs 214 fixed to the rotating shaft 231 are pressed against the rotating shaft 211 and urged downward.

The swing member 232 swings up and down by driving the torque limiter 233 by forward and reverse rotation of the rotating shaft 211.

Above the swinging member 232, a rotatable rotating shaft 236 fitted to a bearing 235 of the crimping device main body and horizontally rotatably supported. The rotation shaft 236 is rotated by receiving the drive from the drive motor M2 via gears G1, G2, G3, G4, and G5.

A pressing cam 237 is fixed to the rotating shaft 236, and can be integrally rotated. By the rotation of the pressing cam 237, the swing member 232 is pressed through the leaf spring 214.

A gear G6 fixed to the shaft end of the rotating shaft 231
Is connected to a gear G7 via a mechanical clutch K1. The pulley on the same axis as the gear G7 rotates the rotation shaft 221 of the lower discharge roller 22 via the timing belt TB3.

Two lower rollers 222 each having a rubber coating layer on the outer peripheral surface are fixed to the rotating shaft 221. The elastic roller 212 of the upper discharge roller 21 comes into pressure contact with and separates from the lower roller 222. The hard roller 223 disposed at the center between the two lower rollers 222 is formed of a hard resin, and can be freely rotated by fitting to the rotation shaft 221. The sponge roller 213 of the upper discharge roller 21 is a hard roller 2
23 and is separated from it.

In FIG. 5, a paper holding member 36 is swingably supported above the intermediate stacker 31. The leading end of the paper holding member 36 is urged by its own weight or a spring,
The sheet is lightly contacted with the upper surface of the sheet placed on the intermediate stacker 31 to prevent the sheet from advancing to the stopping means 33 and to align the sheet.

FIG. 6 and FIG. 7 are front views showing the sheet conveying and sheet discharging processes by the sheet discharging means. Hereinafter, sheet conveyance and sheet ejection during sheet post-processing will be described.

(1) FIG. 6 (a): Paper transport guide plate 1
The first sheet S1 conveyed on the third roller 3 includes a driving roller 16A driven by a driving motor (not shown) and a driven roller 16 which is pressed against and driven by the driving roller 16A.
B and transported. The leading end of the sheet S <b> 1 enters the sheet discharge opening 24 in a state where the upper discharge roller 21 is separated from the lower discharge roller 22.

At this time, the upper discharge roller 21 and the lower discharge roller 22 are rotated forward by the drive motor M1, and
The reference numeral 32 is swung by a predetermined torque of the torque limiter 233 and retracts to an upper position to stop.

(2) See FIG. 6B: The sensor PS1 is
After the passage of the rear end of the first sheet S1 is detected, a predetermined time is measured by a timer, and then the upper discharge roller 21 is driven in reverse by the reverse drive of the drive motor M1. at the same time,
The lower discharge roller 22 is driven by the reverse rotation of the drive motor M1.
Stops rotation by the mechanical clutch K1.

Further, the torque of the torque limiter 233 provided on the rotary shaft 231 is rotated by the reverse rotation of the drive motor M1 to cause the swing member 232 to swing, thereby causing the upper discharge roller 21 to rotate.
Is lowered, and a predetermined pressing force of about 50 g · f is applied. Sponge roller 213 of upper discharge roller 21 driven and rotated
The first sheet S1 is conveyed by a conveying force slightly pressed against the sheet, and is slid on the surface of the intermediate stacker 31 to stop the sheet S1.
Transport in the direction.

(3) See FIG. 6C: First sheet S1
After the rear end of the drive motor M1
Is switched to forward rotation, the upper discharge roller 21 and lower discharge roller 22 rotate forward, and the swinging member 232 is swung by the predetermined torque of the torque limiter 233 and retracts to an upper position to stop. It returns to the same state as (a). In this state, the second sheet S2 is replaced with the first sheet S1.
Similarly to the above, the sheet is conveyed while being sandwiched between the driving roller 16A and the driven roller 16B, and enters the sheet discharge opening 24.

(4) See FIG. 7A: First sheet S1
Sensor PS1 (refer to FIG. 3A)
However, after detecting the passage of the rear end portion of the second sheet S2, a predetermined time is measured by a timer, and then the upper discharge roller 21 is driven in reverse rotation by the reverse rotation drive of the drive motor M1, and shakes by the torque limiter 233. The moving member 232 is swung downward, and is maintained in the same state as in FIG.

The second sheet S2 is conveyed in the same manner as when the first sheet S1 is conveyed, is placed on the first sheet S1, and the rear end thereof comes into contact with the stopping means 33. And stop.

The third and subsequent sheets are also the first sheets S1, 2
6A to 6C are repeated in the same manner as the sheet S2, and the sheets are stacked on the intermediate stacker 31. Even when the thickness of the paper stacked on the intermediate stacker 31 increases, the upper discharge roller 21 presses the paper with a constant urging force of the torque limiter.

(5) See FIG. 7B: After the binding process for the sheet bundle, the pressing cam 23 is driven by the driving rotation of the driving motor M2.
7 rotates and presses the receiving surface 232 </ b> B of the swinging member 232 to make strong contact. Since the upper discharge roller 21 is urged by the pressing spring 214, the pressing force of the upper discharge roller 21 changes according to the thickness of the sheet bundle. The upper discharge roller 21 is strongly pressed by the lower swing member 232 and the pressing spring 214 to strongly press the sheet bundle sandwiched between the lower discharge rollers 22.

In the pressed state of the sheet bundle, the sponge roller 213 of the upper discharge roller 21 is deformed by being pressed by the hard roller 223 of the lower discharge roller 22. Also, in this sheet pressing state, the two hard rollers 212 of the upper discharge roller 21 are connected to the two lower rollers 22 of the lower discharge roller 22.
2 are strongly pressed against each other to securely hold the sheet bundle.

By the forward rotation of the drive motor M1, the upper discharge roller 21 rotates forward. At the same time, the mechanical clutch K1 is engaged, and the lower discharge roller 22 rotates forward. The bound sheet bundle is conveyed while being sandwiched between the forwardly rotating upper discharge roller 21 and the lower discharge roller 22, and is discharged to the discharge tray 41.

In the embodiment of the present invention, a paper post-processing apparatus connected to a copying machine has been described. However, a paper post-processing apparatus used by connecting to an image forming apparatus such as a printer or a facsimile or a light printing machine or the like. It is also applicable to For example, it is also possible to remove the automatic document feeder DF and the image reading device SC which are detachably provided to the image forming apparatus main body 1A, and to apply the invention to a printer specification.

[0068]

According to the present invention, a sheet post-processing apparatus and an image forming apparatus provided with the sheet post-processing apparatus are arranged so that a sheet conveyed by a conveying means can be pressed, separated, and forward / reversely rotated by a discharge upper roller and a sheet discharge lower. By transporting the sheet bundle to the post-processing means by the rollers and enabling the paper bundle to be discharged after the post-processing, the paper transport performance and paper alignment performance have been improved without being affected by the curl of the paper and the static electricity. Is done.

Further, by using a single forward / reverse driving motor and a torque limiter together to perform forward / reverse rotation of the upper discharge roller and lower discharge roller and up / down driving of the upper discharge roller, the mechanism is improved. It is simple and effective in reducing manufacturing costs.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an image forming apparatus equipped with a sheet post-processing device, an automatic document feeder, and an image reading device.

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

FIG. 3 is a schematic view showing a process of conveying and discharging a sheet in a sheet post-processing apparatus.

FIG. 4 is a plan view of a main part of a paper discharging unit.

FIG. 5 is a front view of a sheet discharging unit.

FIG. 6 is a front view showing a sheet conveying and sheet discharging process by a sheet discharging unit.

FIG. 7 is a front view showing a sheet conveying and sheet discharging process by a sheet discharging unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image forming apparatus 1A Image forming apparatus main body 10 Paper transport means 12,13 Paper transport guide plate 14,15,16 Transport roller 20 Paper discharge means 21 Upper paper discharge roller 211,221,231,236 Rotating shaft 212 Elastic roller 213 Sponge roller 214 Pressing spring 22 Discharge lower roller 222 Lower roller 223 Hard roller 23 Crimping means 232 Swinging member 233 Torque limiter 234 Pressing force adjusting spring 237 Pressing cam 24 Discharge opening 30 Paper post-processing means 31 Intermediate stacker 33 Stopping means 34 Binding Means (stapler) 40 Elevating and discharging means 41 Ejection tray (bin) 42 Elevating driving means FS Paper post-processing device K1 Mechanical clutch K2 One-way clutch M1, M2 Drive motor PS1 Sensor S, S1, S2, Paper

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yuji Kanazawa 5-1-27-1, Kichijoji-Kitacho, Tokyo (72) Inventor Mamoru Tomotsune 2-6-41 Nakamachi, Asaka-shi, Saitama (72) Inventor Takashi Yoshida (10) Inventor, Hideyo Ohashi 743-28, Fujikubo, Miyoshi-cho, Iruma-gun, Saitama, Japan (72) Inventor, Yoshihiko Nishimoto Terms (reference) 2H072 AA09 AA22 CA01 FB07 FB09 GA02 GA08 JA02 3F049 CA16 CA33 DA12 EA17 LA02 LA05 LA07 LB03 3F050 AA04 BA04 BB02 BD03 BD07 CA01 CD02 CE05 LA02 LA05 LA07 LB03 3F108 GA02 GA03 GA04 GB01 GB07 HA02

Claims (7)

[Claims] 1. A sheet on which an image has been formed is transported by a transporting means of a paper post-processing apparatus, and then stacked on an intermediate stacker.
In a sheet post-processing device that is post-processed by post-processing means and then discharged by a paper discharging means and placed on a paper discharge tray, the paper discharging means is capable of rotating forward and reverse for transporting and discharging paper while nipping the paper. A discharge roller comprising an upper discharge roller and a lower discharge roller; a pressurizing means for swinging the upper discharge roller so as to be able to press and separate from the lower discharge roller; and a discharge upper roller and a lower discharge roller And a driving unit that uses a drive motor that can rotate forward and reverse to drive the pressure bonding unit and the pressure bonding unit. 2. When the paper conveyed from the conveyance means is stacked on the intermediate stacker by the paper discharge upper roller driven in reverse rotation, the paper discharge upper roller keeps the paper constant regardless of the paper load amount. 2. The sheet post-processing apparatus according to claim 1, wherein the pressure is applied by a pressing force. 3. The sheet post-processing apparatus according to claim 1, wherein a torque limiter is provided in said driving means. 4. A pressing means for pressing the upper discharge roller is provided, and when the sheet bundle post-processed by the post-processing means is discharged by the discharge means, the pressing means is driven to drive the upper sheet discharge roller. 2. The sheet post-processing apparatus according to claim 1, wherein the lower sheet discharge roller is pressed by a roller pressing force to pinch and discharge the post-processed sheet bundle. 5. The sheet discharging lower roller is driven and rotated by the driving unit only when the sheet discharging unit discharges the sheet bundle post-processed by the post-processing unit. A paper post-processing device according to claim 1. 6. An apparatus according to claim 6, wherein said upper sheet discharging roller is provided with a pressing force adjusting means, and when the sheet bundle post-processed by said post-processing means is discharged by said sheet discharging means,
2. The sheet post-processing apparatus according to claim 1, wherein the pressing force of the upper discharge roller is variable. 7. An image forming apparatus comprising the sheet post-processing device according to claim 1. Description: