JP2006193283A - Sheet post-processing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet post-processing device capable of enhancing the reliability to jamming or the like when a sheet is discharged to a processing tray, and enhancing the matching property and the stacking property during the matching by changing the inclination of the tray between when the sheets are discharged, when the bundle is discharged, and when the sheets are matched. <P>SOLUTION: In the sheet-processing device 500, a processing tray 540 which is a temporary sheet stacking means and a stack tray 504 are arranged in a substantially horizontal direction on the upstream side and the downstream side, respectively. Even when a series of post-processing operations are completed, and a processed sheet bundle is discharged into the stack tray 504, the processing tray facilitates the discharge of the sheet bundle in a substantially horizontal condition. The inclination of the processing tray 540 may be changed according to the thickness of the sheet bundle stacked on the processing tray 540. The larger the inclination of the processing tray is, the higher the effect of butting the sheet to a rear end stopper is. However, the larger the thickness of the sheet bundle is, the more the sheet bundle is buckled. Thus, the angle of inclination is reduced to avoid any trouble such as the buckling of the sheet bundle by realizing a steep inclination. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sheet stacking alignment apparatus that aligns and stacks sheets, a sheet processing apparatus including the sheet stacking alignment apparatus, and an image forming apparatus including the sheet processing apparatus.

  2. Description of the Related Art Conventionally, an image forming apparatus in which an in-body discharge type post-processing device is incorporated has been proposed as a post-processing device capable of reducing the occupation area (see, for example, Patent Document 1). This is because, in an image forming apparatus equipped with a post-processing apparatus as shown in FIG. 9, the sheet S on which an image is formed by the main body of the image forming apparatus is temporarily stacked on a processing tray 540 in the sheet processing apparatus 500. Thus, post-sheet processing such as sheet S alignment and binding processing is performed. In the post-processing apparatus having the conventional inclined tray configuration, the discharged sheet S can be expected to return due to the inclination of the tray. Therefore, on the processing tray 540, the simple configuration is not illustrated regarding the alignment in the sheet conveyance direction. The return alignment is performed with something like a return belt.

  In addition, in order to convey the sheet discharged from the image forming apparatus onto a substantially horizontal alignment tray, a discharge roller pair including an upper roller and a lower roller is disposed at the sheet discharge port portion. There is also a processing device (see, for example, Patent Document 2). In this configuration, the upper roller includes a working position where the peripheral surface of the lower roller contacts, a roller position changing means for selectively positioning at a retracted position isolated from the working position, and a driving means for driving the upper roller in the forward and reverse directions. Yes. When the sheet discharged from the image forming apparatus is conveyed onto the alignment tray, the upper roller is controlled to be positioned at the working position, and the upper roller is driven to rotate in reverse so that post-processing is performed on the alignment tray 540. When the sheet bundle is discharged onto the stack tray 581, the upper roller is controlled to be positioned at the working position, and the upper roller is driven and controlled to rotate forward.

In any case, in order to reduce the size of the post-processing device, the loading surface of the temporary stacking tray for temporarily stacking the discharged paper such as the processing tray and the alignment tray is configured to be gently inclined or substantially horizontal. ing.
Japanese Patent Application No. 4388071 JP-A-11-171396

  However, when the temporary stacking tray is gently inclined or substantially horizontal in this way, when the paper ejected to the temporary stacking tray is skewed and ejected, there is no return due to the weight of the paper derived from the tilt of the tray. There is a case where the paper edge does not contact the reference wall with little action. Even if alignment in the direction perpendicular to the paper discharge direction, i.e., the width direction is performed, the skew of the paper cannot be corrected, the paper is stacked obliquely, and the end of the sheet protrudes from the sheet bundle. There was a problem of poor alignment.

  In addition, when the ejected sheet is returned to the reference wall by returning it in a switchback state by a return belt made of a ring-shaped elastic body, when the transported sheet is aligned in the transport direction, the ejected sheet is inclined. Even if not, the force of rotating with respect to the sheet works due to the interaction between the elastic force of the return belt and the return force and the operation of the alignment member for alignment in the width direction at the time of alignment in the width direction, It may not contact the reference wall.

  An object of the present invention is to solve misalignment that occurs when the temporary stacking tray is gently inclined while maintaining the downsizing of the apparatus.

  In order to solve the above-described problems, according to the first aspect of the present invention, there is provided a sheet conveying means for conveying a sheet, a processing tray for stacking sheets conveyed by the sheet conveying means, and the processing tray. A stack tray on which the sheet bundle processed above is stacked; a discharge means for discharging the sheet conveyed from the sheet conveying means onto the processing tray; and the processing tray sandwiching the sheets discharged by the discharge means In the sheet processing apparatus having swingable clamping means for conveying and discharging onto the stack tray, the sheet stacking surface of the processing tray swings.

  According to a second aspect of the present invention, the swingable processing tray swings at an angle such that a sheet stacking surface faces down on a reference side on which the sheets stacked on the processing tray are aligned.

  According to a third aspect of the present invention, the swingable processing tray swings on the holding means side of the processing tray.

  According to a fourth aspect of the present invention, the swingable processing tray swings after the sheet is discharged onto the processing tray.

  According to a fifth aspect of the present invention, the swingable processing tray swings after the leading edge of the sheet discharged to the processing tray passes through the holding means.

  According to a sixth aspect of the present invention, alignment means for aligning the sheets discharged to the processing tray is provided, and the swingable processing tray is configured to align the sheets discharged to the processing tray. The stacking surface swings so that the angle with respect to the horizontal direction becomes large.

  According to a seventh aspect of the present invention, when the sheet is discharged to the processing tray, the swingable processing tray swings so that an angle with respect to a horizontal direction of a sheet stacking surface of the processing tray becomes small. To do.

  According to an eighth aspect of the present invention, the swingable processing tray swings so that an angle with respect to a horizontal direction of a sheet stacking surface of the processing tray becomes small when a sheet bundle is discharged from the processing tray to the stack tray. It is characterized by doing.

  According to a ninth aspect of the present invention, the amount by which the processing tray is swung is changed according to the state of the stacked paper.

  According to the present invention, by changing the inclination of the tray at the time of sheet discharge and at the time of bundle discharge and sheet alignment, the sheet is discharged to the processing tray, thereby improving the reliability against jamming and the like. Sometimes consistency and loadability can be improved.

  Further, when changing the inclination of the tray, the space occupied by the processing tray is reduced by moving the swinging roller side of the processing tray up and down.

  Hereinafter, embodiments of a sheet stacking and alignment apparatus, a sheet processing apparatus, and an image forming apparatus to which the present invention is applied will be specifically described with reference to the drawings.

  Hereinafter, an embodiment of an image forming apparatus according to the present invention will be described with reference to the drawings. 1 is a cross-sectional view of an image forming apparatus main body 200 equipped with a sheet processing apparatus 500 according to the first embodiment of the present invention, FIG. 2 is a top view of the sheet processing apparatus 500, and FIG. 3 is a cross-sectional view of the sheet processing apparatus 500. It is.

<Overall configuration>
As shown in FIG. 1, an image-formed sheet S that is disposed in the upper part of the image forming apparatus main body 200 and in the lower part of the document reading apparatus 100 and is discharged from the image forming apparatus main body 200 is temporarily processed in the processing tray 540. A sheet processing apparatus 500 that stacks and performs post-processing such as staple binding and alignment and then aligns and stacks processed sheets S on a stack tray 504 disposed substantially horizontally will be described as an example. .

  As shown in FIG. 1, a document reading unit 150 is mounted on the image forming apparatus 200, and an automatic document reading device 100 is mounted on the document reading unit 150. The automatic document reader 100 separates the document set upward, feeds it one by one to the left sequentially from the first page, and conveys the document onto the platen glass 102 through a curved path. After reading, the paper is discharged to the paper discharge tray 112. The light of the lamp of the scanner unit 104 is irradiated on the original, and the reflected light from the original is guided to the image sensor 109 via the mirrors 105 and 106 and the lens 107, whereby the original is read. The image of the original read by the image sensor 109 is subjected to image processing and sent to the exposure control unit 202, and laser light is emitted.

  Next, the laser beam is reflected by the rotating polygon mirror, and is further folded back by the reflecting mirror. The surface is uniformly irradiated on the photosensitive drum 203 serving as an image forming unit, and is electrostatic latent. An image is formed. The electrostatic latent image on the photosensitive drum 203 is developed by the developing unit 205 and then transferred as a toner image onto a sheet S composed of paper, an OHP sheet, or the like.

  The sheet S is selectively and appropriately fed from the sheet cassettes 231, 232, 233 and 234 by the pickup roller 238 constituting the sheet feeding unit, separated by the separating unit 237, and fed one by one, by the pair of rollers before registration After the skew is corrected, the toner image is transferred to the transfer position in synchronization with the rotation of the photosensitive drum 203, and the toner image formed on the photosensitive drum 203 is transferred to the sheet S via the transfer belt 211.

  Thereafter, the sheet S is guided to the fixing roller pair 206, and the toner image transferred to the sheet S by being heated and pressed by the fixing roller pair 206 is permanently fixed. The fixing roller pair 206 is in contact with a fixing upper separation claw and a fixing lower separation claw, whereby the sheet S is separated from the fixing roller pair 206.

  The separated sheet S is conveyed to the outside of the image forming apparatus main body 200 by the main body side discharge roller pair 207 and guided to the sheet processing apparatus 500 connected to the image forming apparatus main body 200.

  Next, the configuration of the sheet post-processing apparatus 500 will be specifically described.

  In FIG. 1, a sheet processing apparatus 500 includes a processing tray 540 that is a temporary sheet stacking unit on the upstream side and a stack tray 504 that is disposed substantially horizontally on the downstream side, and a pair of discharge rollers on the main body side of the image forming apparatus 200. The sheet S discharged from 207 is post-processed on the processing tray 540 and stacked on the stack tray 504. The post-processing mode performed in the processing tray 540 includes a sort mode for sorting a plurality of copies, a staple binding mode for binding a plurality of sheets by the staple unit 510, and the like. It is selected and set by means. Note that it is possible to select a staple binding position such as one-point binding or two-point binding, and the staple unit 510 moves from the setting contents such as the sheet size and the binding position to the actual staple binding position.

  As shown in FIGS. 2 and 3, the sheet S discharged from the image forming apparatus 200 is discharged toward the stack tray 504 by a discharge unit 508 including a discharge roller 508 a on the sheet processing apparatus 500 side and a discharge roller 508 b driven by the discharge roller 508 a. However, at the timing when the trailing edge of the sheet S passes the discharge unit 508, the trailing edge of the sheet S is dropped onto the processing tray 540 by the swing roller 550 and is sandwiched between the swing roller 550 and the driven roller 571. .

<Swing roller configuration>
The operation of the swing arm and the swing roller 550 will be described with reference to FIGS.

  As shown in FIG. 4, the swing roller 550 is attached to a swing arm 551 that can swing up and down about a swing roller shaft 552. Drive from a swing arm drive motor (not shown) is transmitted to the swing arm shaft 553 via a swing cam 554. When the swing arm drive motor rotates, the swing arm 551 is rotated by the swing cam 554. And swings up and down about the swing roller shaft 552 as a center. The swing arm 551 is provided with a swing arm tension spring 555 for assisting upward swing.

  The swing roller 550 is connected to a swing roller drive motor (not shown) from the swing roller shaft 552 via a swing roller drive belt 556 and a swing roller driven pulley 557.

<Oscillating roller operation>
The home position of the swing roller 550 is set at an upper portion where it does not come into contact with the sheet S discharged onto the processing tray 540 by the discharge unit 508 (FIG. 4a). When the sheet S is discharged from the discharge unit 508, the swing arm 551 receives the drive of the swing arm drive motor 643 and rotates counterclockwise about the swing roller shaft 552, thereby causing the swing roller 550 to rotate. Then, the trailing edge of the sheet S is pressed by the swing roller 550, and the trailing edge of the sheet is dropped onto the processing tray 540 (FIG. 4b).

  Then, the swing roller 550 forms a nip with the driven roller 571 and rotates counterclockwise under the drive of the swing roller drive motor, whereby the trailing edge of the sheet S on the processing tray 540 is directed to the return belt 560. Until the contact, the sheet S is drawn along the lower guide 561 in the direction opposite to the conveying direction until then (FIG. 4c). Thereafter, the swing roller 550 is again raised to the home position to prepare for the discharge of the next sheet S (FIG. 4a).

<Return belt>
Next, the operation of the return belt will be described with reference to FIGS.

  The return belt 560 is supported in the vertical direction by the discharge roller shaft 509, and is normally set at a position in contact with the sheet S on the processing tray 540. A return belt 560, which is at least one sheet feeding rotary member, arranged in a direction orthogonal to the direction in which the sheet S abuts against the sheet trailing edge stopper 562, is returned by the discharge roller 508 a and the housing 563. The belt pulley 564 is configured to include a belt 565 (FIG. 3), and the discharge roller shaft 509 rotates counterclockwise, whereby the belt member 565 conveys the sheet S toward the sheet trailing edge stopper 562 (FIG. 5a). ).

  Further, the return belt 560 escapes in the sheet thickness direction in accordance with the number of sheets S stacked on the processing tray 540 (FIG. 5b).

  As described above, the rear end of the sheet S is positioned at the end of the processing tray 540 by the counterclockwise rotation of the swing roller 550 and the return belt 560, and is a sheet receiving unit that receives the sheet S on the processing tray 540. A sheet S is fed to the trailing edge stopper 562 and aligned in the sheet conveying direction one by one.

  The alignment in the sheet width direction will be described with reference to FIG.

  The front alignment plate 541 and the rear alignment plate 542 are driven by a front alignment motor and a rear alignment motor (not shown), respectively, and move in a direction parallel to the discharge roller shaft 509.

  When the post-processing apparatus 500 is not in operation, the front alignment plate 541 and the rear alignment plate 542 stand by at the alignment home position where they do not hit the alignment plate when the sheet is conveyed.

  The alignment plates 541 and 542 move to a standby position corresponding to the size of the sheet before the sheet is conveyed from the image forming apparatus. After the sheets S are aligned in the transport direction as described above, the alignment plates 541 and 542 are moved to the alignment positions in the post-processing mode set before the start of the job, whereby alignment in the sheet width direction is performed.

  For example, in the sort mode, when the N-th sheet is aligned in the width direction, the front alignment plate 541 stands by at the reference position, and the rear alignment plate 542 moves from the standby position to the sheet alignment position, so that the front side is the reference. The sheet is discharged onto the stack tray 504 by an operation described later. When aligning the (N + 1) th sheet, the rear alignment plate 542 waits at the reference position, and the front alignment plate 541 moves from the standby position to the sheet alignment position to perform alignment based on the rear side. It is discharged to the tray 504. As a result, the sheets can be stacked on the stack tray 504 in a state of being sorted every time the bundle is discharged.

  Of course, it is also possible to align with reference to the center position of the sheet. In that case, the alignment plates 541 and 542 are aligned by moving from the standby position to the alignment position based on the center position.

  When the staple binding mode is selected, the above-described width alignment operation is performed at a position corresponding to the set staple binding position.

  When the needle binding mode is selected, the needle binding operation is subsequently performed. The stapler unit 510 performs a needle binding operation by driving a staple clinching motor disposed in the stapler unit 510. The stapler unit 510 is movable in the front-rear direction by driving a staple slide motor (not shown).

  When the job is started, the stapler unit 510 moves to the actual staple binding position calculated from the contents of the staple binding position set before the job start and the sheet size. The stapler unit 510 performs a staple binding operation on the aligned sheet bundle S that has undergone the above-described width direction alignment.

<Bundle discharging means>
Next, the bundle discharging means will be described with reference to FIG.

  After completion of alignment in the sheet conveying direction, alignment in the sheet width direction, and staple binding operation, the swing roller 550 is driven by the swing arm drive motor until it contacts the sheet bundle S around the swing roller shaft 552. After descending (FIG. 6 a) and forming a nip with the driven roller 571, the sheet rotates in the clockwise direction until the rear end of the sheet bundle S reaches the vicinity of the upper end of the rear end alignment wall 570 and stops (FIG. 6 b).

  Thereafter, the swing roller 550 is separated from the sheet bundle S and returns to the home position (FIG. 6c). At the same time, the trailing edge aligning wall 570 is swung in the direction opposite to the sheet conveyance by the cam 572 located below the trailing end aligning wall 570 around the cam rocking rotation shaft 573.

<Seat trailing edge alignment>
A means for discharging, aligning and stacking the sheet bundle S on the processing tray 540 onto the stack tray 504 will be described with reference to FIG. The rear end alignment wall 570 is biased by a spring 512, and swings about the swinging rotation shaft 573 by contacting the cam 572 at the home position (FIGS. 3 and 7).

  In a state where the rear end of the sheet bundle S discharged by the bundle discharging means is in contact with the upper end of the rear end alignment wall 570 (FIG. 6b), the rear end alignment wall 570 is retracted upstream in the sheet conveying direction (FIG. 6c). The rear end of the sheet bundle S is brought into contact with the inclined surface portion of the rear end alignment wall 570 (FIG. 7a). In the process of returning the retracted trailing edge alignment wall 570 to the home position about the pivot axis, the trailing edge of the sheet bundle S is aligned by pressing the trailing edge of the sheet bundle S horizontally with the trailing edge alignment wall 570. , The sheet bundle S is stacked on the stack tray 504 (FIGS. 7b and 7c).

  The sheet bundle placed on the stack tray 504 is pulled back toward the trailing edge alignment wall by the sheet return member 583 after the sheet bundle is discharged and pressed from the upper surface of the sheet bundle. The sheet return member 583 is a paddle-shaped member, and is configured to rotate around a paddle rotation shaft 590 (FIGS. 6 and 7) provided in the rear end alignment wall. Each time the bundle is discharged onto the stack tray 504, the sheet return member 583 rotates counterclockwise to pull back the discharged sheet bundle in the direction of the rear end alignment wall 570 and press the rear end of the sheet bundle. Can do.

  The sheet return member 583 is held in the state shown in FIGS. 6a and 6b except during the sheet return operation, and holds the sheet. The position of the member at this time is detected by a paddle home position sensor 532 (not shown).

  The stack tray 504 is configured to be movable up and down by driving means (not shown) in order to keep the upper surface height of the stacked sheet bundle S constant.

  In this embodiment, the sheet stacking surface of the stack tray 504 is set to be substantially horizontal. However, even when the sheet stacking surface is inclined, the sheet trailing edge aligning means works effectively, and the sheet stacking surface is substantially set. When it is horizontal, the effect is further increased. Further, by setting the sheet stacking surface 504a to an inclination angle of 18 ° or less downward toward the sheet rear end alignment wall, the sheet stacking surface 504a is discharged from the rear end of the bundle of sheets stacked on the stack tray 504 and the processing tray 540. The apparatus can be reduced in size while avoiding interference with the subsequent sheet bundle.

<Processing tray>
Next, an operation for changing the inclination angle of the stacking surface of the processing tray according to the embodiment of this patent will be described with reference to FIG.

  The processing tray 540 swing arm 551 is in the standby position, and the swing roller 550 is opened so that the leading edge of the discharged sheet hits the swing arm 551 and the paper discharge operation is not hindered. At this time, the processing tray is in a substantially horizontal state, and the discharge of the sheet is not obstructed by taking a large opening area (FIG. 8A). When the leading edge of the sheet S is downstream of the bundle paper discharge roller, the processing tray 540 rotates in the clockwise direction in the drawing around the rotation axis in the vicinity of the trailing edge stopper 562. At the same time, the rear end alignment wall 570 slides upward in order to support the sheet bundle stacked on the processing tray 540 (FIG. 8B). When the trailing edge of the sheet passes through the paper discharge roller 508, the swing arm 551 descends, and the swing roller 550 at the front end of the swing arm 551 and the driven roller 571 disposed on the upper end of the rear end alignment wall 570. A sheet can be sandwiched between them (FIG. 8-c). Thereafter, the swing roller 550 rotates counterclockwise in the drawing, returns the sheet to the return belt 560, and then returns the sheet until it hits the trailing end stopper 562 by the return belt (FIG. 8D). When the sheet hits the trailing end stopper 562, the swing arm 551 returns to the standby position again, and the swing roller is in an open state. In this state, alignment in the direction perpendicular to the conveyance direction, that is, in the width direction is performed using the front alignment plate and the rear alignment plate.

  When the alignment in the width direction is completed, the processing tray 540 and the trailing edge alignment wall 570 are again in the original state of FIG. 8A to prepare for the discharge of the next sheet.

  Further, when the series of post-processing operations are completed and the processed sheet bundle is discharged to the stack tray 504 (FIG. 8-ef), the processing tray is in a substantially horizontal state to facilitate discharge of the sheet bundle. .

  By the way, the inclination of the processing tray 540 may be changed according to the thickness of the sheet bundle stacked on the processing tray 540. The greater the tilt of the processing tray, the greater the effect of the sheet hitting the trailing edge stopper.However, the greater the thickness of the sheet bundle, the more likely the sheet bundle will be crushed. Avoid the harmful effects of steep slopes such as hip breaks.

  As described above, when the sheet is discharged, the processing tray is set to a substantially horizontal state, so that the opening for discharging the sheet is enlarged, and even when a large curled sheet is discharged, the sheet is discharged. It is possible to prevent obstruction, and the reliability of the device against jamming is increased.

  On the other hand, after the leading edge of the sheet passes through the swing roller and when aligning the sheet, the action of returning due to the weight of the paper guided by the inclination of the tray is increased by increasing the inclination of the processing tray. The sheet end is easy to hit the trailing end stopper. At the same time, it is easy to correct sheet skew correction. Accordingly, sheet alignment and stackability can be improved.

Cross-sectional explanatory drawing which shows the whole structure of the sheet processing apparatus which concerns on 1st embodiment. Similarly, a top view of the sheet stacking alignment apparatus. Similarly, sectional drawing which shows the moving mechanism of the alignment member provided in the rocking roller and the processing tray. Similarly, sectional drawing which shows operation | movement of a rocking | fluctuating roller. Similarly, sectional drawing which shows operation | movement of a return belt. Similarly, sectional drawing which shows discharge operation | movement of a sheet bundle. Sectional drawing which shows the alignment operation | movement of the sheet bundle rear end which concerns on 1st embodiment. The figure explaining operation | movement of a process tray inclination-angle change. Sectional drawing which shows the whole structure of the conventional sheet processing apparatus.

Explanation of symbols

S Sheet 100 Document Reading Device 101 Document Set Tray 102 Platen Glass 104 Scanner Unit 105 Mirror 106 Mirror 107 Lens 109 Image Sensor 112 Paper Discharge Tray 150 Document Reading Unit 202 Exposure Control Unit 203 Photosensitive Drum 205 Developing Unit 206 Fixing Roller Pair 207 Main Body Side discharge roller 200 Image forming device 237 Separating means 238 Pickup roller 500 Sheet post-processing device 504 Stack tray 508 Discharge unit 508a Discharge roller 508b Discharge roller 509 Discharge roller shaft 510 Staple unit 512 Rear end alignment wall bias spring 520 Paddle 540 Processing tray 541 Front alignment plate 542 Rear alignment plate 550 Oscillating roller 551 Oscillating arm 552 Oscillating roller shaft 553 Oscillating arm shaft 554 Oscillating cam 5 5 Swing arm tension spring 556 Swing roller drive belt 557 Swing roller driven pulley 560 Return belt 561 Lower guide 562 Seat rear end stopper 563 Housing 564 Return belt pulley 565 Belt 570 Rear end alignment wall 571 Driven roller 572 Cam 573 Swing Rotating shaft 574 Pinion gear 575 Rear end alignment wall home position sensor 577 Rack support roller 578 Rack gear 580 Bundle discharge means 581 Stack tray 582 Gripper 583 Sheet return member (paddle)
585 Front end regulating plate 590 Paddle rotation shaft 595 Sheet detection means 644 Rear end alignment wall drive motor

Claims (9)

Sheet conveying means for conveying sheets, processing tray for stacking sheets conveyed by the sheet conveying means, stack tray for stacking bundles of sheets processed on the processing tray, and processing sheets conveyed from the sheet conveying means In a sheet processing apparatus comprising: a discharging unit that discharges on a tray; and a swingable holding unit that holds the sheet discharged by the discharging unit, and that conveys and discharges the sheet onto the processing tray.
A sheet processing apparatus, wherein a sheet stacking surface of the processing tray swings.   2. The sheet processing apparatus according to claim 1, wherein the swingable processing tray swings at an angle such that a sheet stacking surface faces a reference side on which the sheets stacked on the processing tray are aligned. A sheet processing apparatus.   3. The sheet processing apparatus according to claim 1, wherein the swingable processing tray swings on the holding means side.   4. The sheet processing apparatus according to claim 1, wherein the swingable processing tray swings after the sheet is discharged onto the processing tray.   5. The sheet processing apparatus according to claim 1, wherein the swingable processing tray swings after a leading end of a sheet discharged to the processing tray passes through the holding means. . 6. The sheet processing apparatus according to claim 1, further comprising alignment means for aligning the sheets discharged to the processing tray,
The sheet processing apparatus, wherein the swingable processing tray swings so that an angle with respect to a horizontal direction of a sheet stacking surface of the processing tray becomes large when aligning sheets discharged to the processing tray.   7. The sheet processing apparatus according to claim 1, wherein the swingable processing tray swings so that an angle with respect to a horizontal direction of a sheet stacking surface of the processing tray becomes small when a sheet is discharged to the processing tray. A sheet processing apparatus.   8. The sheet processing apparatus according to claim 1, wherein the swingable processing tray has a small angle with respect to a horizontal direction of a sheet stacking surface of the processing tray when the sheet bundle is discharged from the processing tray to the stack tray. A sheet processing apparatus that swings as described above.   9. The post-processing apparatus according to claim 1, wherein an amount of swinging of the processing tray is changed according to a state of the stacked paper.

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