JP5287182B2 - Paper post-processing apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a sheet post-processing apparatus that processes a sheet after an image is formed in an image forming apparatus such as a copying machine or a printer, and an image forming apparatus including the same.

  Image forming devices are becoming more colored and higher in image quality, and the quality of printing paper is diversifying, such as paper that supports color printing and recycled recycled paper. Various measures have been taken to improve transport and stackability. Yes.

  For example, when paper with a large amount of friction between sheets (surface-coated paper, etc.) is discharged to the paper output tray, the subsequent paper is discharged onto the stacked paper, causing friction between the paper and static electricity. The stack paper and the subsequent paper are brought into close contact with each other, and the subsequent paper pushes out the stack paper. For this reason, a stack defect is likely to occur, for example, the leading stack paper falls from the paper discharge tray.

  In such a case, the discharge angle of the stacked paper is reduced, the time when the subsequent paper to be discharged and the stacked paper are in contact with each other, or the transport distance is reduced, so that Extrusion is less likely to occur.

For example, the invention disclosed in Patent Document 1 improves stackability by changing the inclination angle of the paper discharge tray according to the post-processing mode. Further, the invention disclosed in Patent Document 2 changes the tray angle according to the post-processing mode by the tray angle changing means to which the stacking tray is mounted, and sets the number of stacked sheets when the saddle stitching or the middle folding post-processing is performed. I try to do more. Further, the invention disclosed in Patent Document 2 can cope with the thickness of the stapled bundle of paper by enabling opening and closing of the upper side of the paper discharge port.
JP-A-10-324445 Japanese Patent No. 3970509

  However, in the inventions disclosed in Patent Document 1 and Patent Document 2, when discharging a paper with a large coefficient of friction or a paper with a large curl, it is not possible to prevent a stack failure or a paper drop, and there is an alignment accuracy. There was a problem of being lowered.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and is capable of preventing stack failure and falling of paper and improving alignment accuracy when discharging paper having a large friction coefficient and paper having a large curl. It is an object of the present invention to provide a post-processing apparatus and an image forming apparatus including the post-processing apparatus.

In order to achieve the above object, according to a first aspect of the present invention, there is provided, as a first aspect, a conveying unit that conveys a sheet output from the image forming apparatus, a sheet discharging unit that discharges the sheet to the outside of the housing, and a discharged sheet. A sheet post-processing apparatus having a stacking unit for stacking a sheet, wherein the sheet discharge unit changes a discharge angle at which the sheet is discharged out of the housing, and a plurality of discharge guides whose angles can be adjusted independently. there is provided a sheet post-processing apparatus characterized by having a plate.

  In order to achieve the above object, the present invention provides, as a second aspect, an image forming apparatus provided with the sheet post-processing apparatus according to the first aspect of the present invention, either integrally or separately. .

  According to the present invention, there is provided a paper post-processing device and a paper post-processing device that can prevent stacking failure and paper fall and improve alignment accuracy when discharging paper having a large friction coefficient or paper having a large curl. An image forming apparatus can be provided.

A preferred embodiment of the present invention will be described.
FIG. 1 shows a configuration of a sheet post-processing apparatus according to the present embodiment.
The transfer paper discharged from the image forming apparatus 100 passes through the inlet guide plate 201 of the paper post-processing device 200 and is carried into the paper post-processing device 200 by the transport roller 202. The conveyance paths 220 and 221 are conveyance paths when the sheet is not bound, and the conveyance direction of the sheet is switched by the branching claws 230 and 231. The paper sent to the transport path 220 is transported by the transport roller 204, and the paper sent to the transport path 221 is transported by the transport rollers 207a and 207b. When the binding process is performed, the sheet is sent in the direction of the conveyance path 222 and is sent in the direction of the binding device 404 by the conveyance roller 208.

  When the non-staple mode is selected in the operation unit of the image forming apparatus 100, the paper passes through the branching claws 230 and 231 (the normal branching claws 230 and 231 guide the paper toward the non-staple conveyance path 220. The paper is discharged and stacked on the stacking tray 502 by paper discharge rollers 205 and 206.

The stacking tray 502 is controlled so that it is gradually lowered by a drive motor (not shown) when the number of sheets increases, and a plurality of sheet amount sensors 803 and 804 are provided for the sheets stacked on the stacking tray 502. By detecting the detection plate 502a 502, the number of stacked sheets can be detected. Note that the sheet stacking amount may be detected by discharging the sheet to the stacking tray 502 and counting it.
The paper discharge roller 205 is attached to the paper discharge guide plate 240, and the paper discharge roller 206 is attached to the paper discharge guide plate 243. Further, the paper discharge guide plates 240 and 243 have separate driving units, and are usually positioned in a substantially horizontal state. The paper discharge guide plates 240 and 243 are configured to transmit the conveyance drive to the paper in the closed state. However, as will be described later, a paper is provided at the end of the paper discharge roller 205 to wave the paper. The sheet can be conveyed even if the nip between the paper discharge rollers 205 and 206 is separated. In this embodiment, it is assumed that the paper discharge roller 205 is a driving roller and the paper discharge roller 206 is a driven roller.

As shown in FIG. 2, the paper discharge guide plates 240 and 243 can be moved up and down independently, and the paper discharge angle can be changed by operating them together. When the upper and lower paper discharge guide plates 240 and 243 are set to be almost horizontal, the discharge angle of the paper 504 is substantially horizontal (FIG. 2, solid line). When the upper and lower discharge guide plates 240 and 243 are both raised, the discharge angle of the discharge rollers 205 and 206 becomes smaller than the angle of the stacking tray 502 (FIG. 2, broken line).
By operating the paper discharge guide plates 240 and 243 independently, the paper discharge angle, the distance between the paper discharge guide plates, and the distance between the paired paper discharge rollers 205 and 206 can be freely changed. The discharge angle can be controlled to suit the situation such as the number of sheets and characteristics.
In addition, since the interval between the discharge guide plates 240 and 243 can be arbitrarily adjusted by controlling the discharge angles of the discharge guide plates 240 and 243 to different angles, various post-processing such as a bundle discharge mode during stapling can be performed. The mode can be supported.

The operation of the paper discharge guide plates 240 and 243 will be described. In FIG. 3, the lower paper discharge guide plate 240 can be rotated upward and about the shaft 244 via the link 241b by the rotation of the cam 241a. The drive mechanism of the cam 241 is composed of a stepping motor (not shown) and a home position detection sensor. The position where the paper discharge guide plate 240 is lowered is the home position, and the rotation angle from the home position is the rotation pulse of the stepping motor. An arbitrary angle can be set steplessly by numerical control.
When sheets are continuously stacked on the stacking tray 502, the top surface of the stacked sheets is not always at the same angle as the stacking tray 502, and may change depending on the curl state, the number of stacked sheets, and the like. Many. Therefore, by changing the discharge angle in a stepless manner according to conditions such as the angle of the loaded paper surface and the paper surface height, it is possible to prevent stack failures and paper dropping and improve alignment accuracy.

  In FIG. 4, the paper discharge roller 205 is rotated by a driving force transmitted from a pulley installed in a motor 303 via a paper discharge drive timing belt 304, a pulley 305, a timing belt 306, and a pulley 307. The variable angle shaft 244 of the paper discharge guide plate 240 and the rotation shaft of the pulley 305 are coaxial, and the distance between the pulley 305 and the pulley 307 does not change even if the angle of the paper discharge guide plate 240 is raised or lowered.

  As shown in FIG. 5, the upper sheet discharge guide plate 243 is configured to move up and down along with the rotation of the rotation plate 310 via the timing belt 309 by rotating the stepping motor 308. The rotary plate 310 has a shaft 243a, and the paper discharge guide plate 243 is attached to the shaft 243a, and is rotatable about this. In the present embodiment, when the paper discharge guide plate 243 is in the horizontal position, the home position is set, and the angle of the paper discharge guide plate 243 is detected by the slit 310a provided in the rotary plate 310 and the position detection sensor 311 of the rotary plate 310. To do. Further, the paper discharge guide plate 243 is normally abutted by its own weight with the paper discharge roller 206 in contact with the paper discharge roller 205, and pressure is applied to the nip of the paper discharge rollers 205 and 206. .

The center of the rotation axis of the rotation plate 310 is coaxial with the rotation axis of the sheet discharge guide plate 240 so that the nip positions of the sheet discharge rollers 205 and 206 are the same even if the angle of the sheet discharge guide plates 240 and 243 is changed. It has become. Even when the angle of the paper discharge guide plates 240 and 243 is changed, the nip of the paper discharge rollers 205 and 206 is not changed, and the paper discharge angle to the stacking tray 502 is proportional to the angle change amount of the paper discharge guide plates 240 and 243. It has a structure that can be changed at an angle. As a result, even if the angle of the paper discharge guide plates 240 and 243 is changed, the nip position and angle of the paper discharge rollers 205 and 206 for conveying the paper do not change, and the discharge angle of the paper discharge guide plates 240 and 243 is stacked. Even if it is reduced with respect to the tray 502, the nip angle of the paper discharge rollers 205 and 206 is changed in a direction to increase with respect to the stacking tray 502, and the discharge angle is not offset. Therefore, the paper discharge angle to the stacking tray 502 can be adjusted with simple control.
Further, by making the rotation shafts of the discharge guide plates 240 and 243 coaxial, the nip positions and angles of the discharge rollers 205 and 206 of the paired discharge guide plates 240 and 243 are always constant with a simple structure. It is possible to make the paper discharge angle variable with a simple mechanism.

  By making the angles of the paper discharge guide plates 240 and 243 different from each other, the nip of the paper discharge rollers 205 and 206 of the paper discharge guide plates 240 and 243 can be separated, for example, In order to transport and discharge the stapled paper bundle from the staple tray, it is possible to perform transport and open / close operations with the paper discharge rollers 205 and 206 spaced apart.

  Further, the interval between the paper discharge rollers 205 and 206 can be changed according to conditions such as the number of paper bundles and paper thickness. For example, the paper discharge guide 240 can be set at a horizontal position, and the paper discharge guide plate 243 can be set at an upward angle so that the interval between the paper discharge rollers 205 and 206 is increased.

  The sheet discharge guide plate 243 has a structure that can freely rotate in the vertical and horizontal directions about the shaft 243a. However, when the nip interval between the sheet discharge rollers 205 and 206 is separated, the sheet discharge guide plate 243 is configured with the pin 310a. It is supported by that and it is regulated not to go down any more.

  Further, if the discharge guide plate 240 is set to an angle above the horizontal and the discharge guide plate 243 is set to an angle upward from the discharge guide plate 240, the transport roller 205 with respect to the inclination angle of the stacking tray 502. , 206 can be freely changed with the nip separated. When adjusting the pressure applied to the nip between the paper discharge rollers 205 and 206 when paper is discharged, fine adjustment is possible by the difference in angle between the paper discharge guide plates 240 and 243.

  As the transport path 222 in the staple mode, two transport routes, a first route 222a and a second route 222b, are provided in parallel. A switching claw 232 for switching the paper transport direction to each transport route is provided upstream of these two transport routes. The paper transported to the first transport route 222a temporarily stops in the middle of the transport route, and is transported again by the transport roller 212 in synchronization with the paper transported through the second transport route 222b by the transport roller 209. By starting, it is possible to overlap sheets in the middle of the conveyance path.

  At the rear end (upstream in the transport direction) of the alignment tray 405, a reference fence 403 is provided for abutting and aligning the fed sheets. The reference fence 403 is disposed on the upstream side of the alignment tray paper discharge roller 211.

  The overlapped sheets are sent to the alignment tray discharge roller 211 by the transport roller 210. A fur brush 211a is provided integrally with the roller on the lower side of the alignment tray discharge roller 211, and when the sheet falls on the reference fence 403 of the alignment tray 405, it rotates in the dropping direction. Is scraped off.

  On both sides of the alignment tray 405 in the direction perpendicular to the conveyance direction, joggers 401 are provided that align the sheets discharged to the alignment tray 405 by pushing in the lateral direction.

  A hitting roller 213 is provided below the alignment tray discharge roller 211 and above the alignment tray 405 to convey the discharged paper to the reference fence 403 side. The hitting roller 213 is configured to be movable between a retracted position retracted from the conveyance path and an alignment position for aligning the paper, and when the paper is discharged, the paper is placed on the reference fence 403 side at the retracted position. When approaching, it moves to the alignment position. The hitting roller 213 is operated mainly when paper is discharged to the alignment tray 405 one by one.

  A tip stopper 402 is provided on the downstream side of the hitting roller 213 so as to be substantially perpendicular to the alignment tray 405. The leading end stopper 402 can move at an arbitrary speed in accordance with the situation along the sheet conveyance direction. For this reason, the leading edge of the paper ejected from the paper ejection roller is abutted to regulate the amount of protrusion, and the paper is moved upstream so as to approach the reference fence 403 side, thereby aligning the paper in the transport direction. The front end stopper 402 is operated mainly when two or more sheets are discharged. This is because, when sheets are overlapped and discharged, if the sheet is struck back and transported by the roller 213, the sheet in contact with the roller is likely to be misaligned with other sheets, and misalignment in the alignment tray 405 is likely to occur. Because.

  Further, the front end stopper 402 is rotated when the sheet bundle is discharged and retracted from the conveyance path, thereby enabling the discharge of the sheet bundle.

  In the vicinity of the reference fence 403, a stapler 404 for binding the aligned sheets is provided. The stapler 404 can move along the reference fence 403, and can move to positions corresponding to various sizes or positions such as two-point binding. Further, the stapler 404 is provided with a mechanism that can change the angle at the end face position of the paper, and can be bound obliquely to the corner of the paper.

  In the alignment tray 405, a discharge belt 406 is stretched in the transport direction, and a discharge claw 406a that hooks stapled paper and discharges it from the alignment tray 405 is installed on the discharge belt 406.

  The stapled sheet bundle is hooked by the claw 406a of the discharge belt 406, conveyed from the alignment tray 405 along the guide plate 242 attached integrally with the discharge guide plate 240, and stacked by the discharge rollers 205 and 206. Release to 502.

When the non-staple mode is selected in the operation unit of the image forming apparatus 100, the paper passes through the branching claws 230 and 231 (the normal branching claws 230 and 231 are in a state of guiding the paper in the direction of the non-staple conveyance path 220. The paper is discharged and stacked on the stacking tray 502 by paper discharge rollers 205 and 206 (installed). Information such as the type and size of the sheet conveyed from the image forming apparatus 100 is recognized by a signal transmitted from the image forming apparatus 100 to the post-processing apparatus 200 for each sheet. For example, when the conveyed paper 504 is plain paper, the paper discharge guide plates 240 and 243 are set to the home position (horizontal position in this embodiment), and the paper discharge roller 206 is connected to the paper discharge guide plate 243. The vehicle rides on its own weight, and is conveyed and discharged at the nip between the discharge rollers 205 and 206.
By changing the angle at which the paper is discharged to the stacking tray 502 according to the conditions such as the size, type, thickness, and weight of the paper, the stackability of the paper stacked on the stacking tray 502 can be improved.
When the sheet 504 to be discharged and conveyed has high adhesion (for example, high friction) between the sheets, such as coated paper used in color copying, the subsequent sheet contacts the sheet surface loaded on the stacking tray 502. However, when the paper is discharged, the stacked paper may move and the stackability may deteriorate (FIG. 6). In the case of such a sheet, the discharge angle of the discharge guide plates 240 and 243 is reduced with respect to the inclination angle of the stacking tray 502, and the incident angle at which the leading edge of the subsequent sheet 504 contacts the stacked sheet 505 is decreased. (FIG. 2, broken line), the stacking property is improved by releasing the force of pushing the stacked paper 505 or shortening the distance that the papers 504 and 505 are brought into contact with each other. Further, by setting the paper discharge angle of the paper discharge guide plates 240 and 243 upward from the horizontal, the paper 504 and the stacked paper 505 are less likely to be in close contact with each other, and the paper 505 is less likely to be pushed out and stackability is improved. (FIG. 7).
The larger the paper, the longer the contact distance with the paper 505 when the paper 504 is discharged, and the paper 505 is easily pushed out. In addition, thick paper or the like has a small friction between stacked sheets, and a stack failure due to slippage is likely to occur during discharge of the subsequent sheet 504. Even in such a case, by reducing the incident angle of the paper 504 to the paper 505, it is possible to improve the stackability by releasing the force for pushing the paper 505 (FIG. 7).

  Further, the stacking property of the sheets stacked on the stacking tray 502 is improved by changing the sheet discharge angle according to the number of sheets stacked on the stacking tray 502 and the curl amount. When the number of sheets stacked on the stacking tray 502 is small or when the curl amount is small, the sheets 505 are stacked along the inclination of the stacking tray 502 as shown in FIG. Therefore, the stacked paper 505 is not easily displaced even if the paper 504 discharged subsequently comes into contact. On the other hand, when the number of stacked sheets is large or the amount of curl is large, as shown in FIG. 9, the stacked upper surface of the stacked sheets 505 is almost horizontal or tilted in a direction orthogonal to the transport direction. It's easy to do. In such a state, the stacked sheets 505 are stacked in an unstable state, and even a slight friction or the like is likely to shift in the sheet discharge direction or a direction perpendicular thereto. Therefore, the stacked paper 505 is pushed out by the subsequent paper 504 and stacking failure is likely to occur. Therefore, when a large number of sheets are stacked or a sheet with a large curl amount is discharged, the discharge angle of the discharge guide plates 240 and 243 is set to the inclination angle of the stacking tray 502 as shown in FIG. By reducing the incident angle at which the leading edge of the succeeding paper 504 comes into contact with the stacked paper 505, or by setting the angle so that the paper 504 being discharged is not in contact with the stacked paper 505 as much as possible. Is less likely to be pushed out and stackability is improved.

  In the stack state as shown in FIG. 9, the stacked paper 505 tends to be pushed out as the discharge speed of the paper 504 increases. Therefore, when the paper discharge speed of the paper 504 is high, stackability can be improved by reducing the discharge angle with respect to the inclination angle of the stacking tray 502 as shown in FIG.

If the leading edge of the paper hangs down during paper discharge, the stacking property deteriorates. Therefore, as shown in FIG. 11, it is possible to wave the paper by providing ridges on both sides of the paper discharge roller 205 and to discharge the paper with a waist. It is common.
However, for example, when the paper 504 to be discharged and transported is a hard paper such as a coated paper or a thick paper used in color copying, the nip portion of the discharge roller 205 and 206 and the nip portion of the discharge rollers 205 and 206 A peripheral speed difference from (B section) occurs, and the paper is rubbed and stains are likely to occur on the image surface. Further, there may be a problem that the image surface of the sheet is folded due to the step between the A part and the B part and the pressure at the nip part. Therefore, in the present embodiment, as shown in FIG. 12, the opening angle of the paper discharge guide plates 240 and 243 is adjusted, the nip pressure of the paper discharge rollers 205 and 206 is reduced, or a slight gap is formed in the nip portion. To prevent image smears and creases from occurring on the paper.

  It is possible to improve productivity by transporting the paper as fast as possible. For example, if the paper is transported and discharged at a speed higher than the transport speed of the paper discharged from the image forming apparatus 100, The necessary time can be earned by the shift operation. However, when the paper is discharged at a high speed, it is likely that the paper jumps out too much in the transport direction or does not return to the rear end side with the stacking tray 502. Further, as the paper discharge speed increases, the stacked paper 505 is more easily pushed out to the subsequent paper 504 as illustrated in FIGS. 6 and 9. Therefore, in this embodiment, when the paper discharge speed is high, as shown in FIGS. 7 and 10, the discharge angle is set upward, the paper drop position is at the front, and the paper is prevented from jumping too much. . Further, since the paper 505 is less likely to come into contact with the paper 504 during discharge, the paper 505 is less likely to be pushed out.

Next, the operation in the staple mode will be described.
A start signal, a conveyance speed signal, a mode signal for instructing the staple mode, a signal indicating the staple position / angle / binding position, and a signal indicating the size / type of the conveyed paper from the image forming apparatus 100 to the post-processing apparatus 200 Etc. are sent. With these signals, the post-processing apparatus 200 switches the transport path so that the paper is transported at the same first transport speed as the main body and transported to the alignment tray 405.
The tapping roller 213 is also retracted to the retracted position so that the sheet can be received. In the alignment tray 405, the jogger 401 is moved to a standby position corresponding to the size. The stapler 404 moves and rotates to a position corresponding to the paper size, angle, and binding position, and prepares to receive the paper. The leading edge stopper 402 rises in the alignment tray 405, moves to a predetermined position, and prepares to receive a sheet.

Subsequently, a sheet is sent out from the image forming apparatus 100. The post-processing device 200 receives the paper and transports it by the transport rollers 202 and 203, switches the switching claw 230 to the paper transport path 222 side, and transports the paper to the transport path 222 side.
The transported paper is sent to a prestack unit in which transport paths are provided in parallel. The paper is sent to the respective conveyance paths by the branching claws 232 installed in front of the prestack unit. The first sheet is sent to the first route 222a and temporarily stops in the first route 222a. The next fed sheet is conveyed to the second route 222b by the branching claw 232. The sheet conveyed to the second route 222b is conveyed without stopping on the way. When the sheet conveyed on the second route 222b joins the first route 222a downstream, the sheet stopped on the first route 222a is conveyed again at the same time, and at the same time, the sheet is aligned with the alignment tray. In order to gain time for alignment at 405, the sheet is accelerated to a second conveyance speed that is faster than the first conveyance speed, and two sheets are overlapped and conveyed.
The sheets conveyed in a superimposed manner are discharged from the alignment tray discharge roller 211 to the alignment tray 405. At the same time as the paper is discharged, the transport speed by the alignment tray paper discharge roller 211 is returned to the first transport speed in order to receive the subsequent paper. At this time, the peripheral speed of the fur brush 211a integrated with the alignment tray paper discharge roller 211 also becomes the first transport speed.
When the sheet is discharged, the leading end stopper 402 abuts the leading end of the sheet discharged from the alignment tray discharge roller 211 to regulate the amount of protrusion, and drops the sheet toward the reference fence 403. When the sheet starts to fall, the leading end stopper 402 is lowered so as to bring the leading end of the sheet toward the reference fence 403 while chasing the leading end of the falling sheet. When the trailing edge of the paper approaches the reference fence 403, the paper is scraped off by the fur brush 211a and falls to the reference fence 403, and at the same time, the leading end stopper 402 moves to the reference fence 403 side. As a result, the discharged paper is pressed against the reference fence 403, and the paper is aligned in the transport direction. After that, the front end stopper 402 is stopped for a predetermined time and retracted to the subsequent sheet receiving position, and at the same time, the alignment in the horizontal direction is performed by the jogger 401, thereby aligning in a direction orthogonal to the transport direction of the stacked and discharged sheets. I do. Thereafter, the stapler 404 performs an operation of binding the sheet bundle.

  The stapled sheet bundle is hooked by the claw 406a of the discharge belt 406 and discharged from the alignment tray 405 to the stacking tray 502 through the discharge guide plates 240 and 243. When the sheet bundle is discharged, adjustment is made so that the nips of the discharge rollers 205 and 206 of the discharge guide plates 240 and 243 are opened. As for the discharge angle of the paper discharge guide plate, for example, when the number of paper bundles is small, the paper is stiffened and the front end is discharged relatively straight, so that the paper is discharged in a nearly horizontal state. . If the number of paper bundles is large, the paper is thick and cannot be seated, so the leading edge of the paper hangs down, touches the stacking tray 502 or the loaded paper 505, and tends to be rounded. Paper is ejected upward.

In this embodiment, before the leading edge of the sheet bundle reaches the discharging rollers 205 and 206, the nip of the discharging rollers 205 and 206 is opened in advance, and the leading edge of the sheet bundle ensures the nip position of the discharging rollers 205 and 206. The nip between the paper discharge guide plates 240 and 243 is closed at a timing after the passage of the paper, and the paper discharge roller 206 as a driven roller is placed on the paper discharge roller 205 by the weight of the paper discharge guide plate 243. The conveying force is transmitted to the sheet bundle, and the bundle is discharged to the stacking tray 502.
Thereafter, the above operation is repeated for the designated number of copies.

  FIG. 13 shows the configuration of the control system of the sheet post-processing apparatus according to this embodiment. Signals from the control unit 150 of the image forming apparatus 100 and the sensors in the paper post-processing apparatus 200 are input to the control unit 250 of the paper post-processing apparatus 200. The control unit 250 of the paper post-processing apparatus 200 controls various drivers 251 based on these signals, and a motor 261 for driving the paper discharge guide plate 240 and a motor 262 for driving the paper discharge guide plate 243. In addition, each of the motors 263 to 268 for driving other members (conveying roller, branch claw, hitting roller, etc.) is driven to execute the above operation. Since the configuration of the control system is the same as that of a known paper post-processing apparatus, a detailed description is omitted.

As described above, according to the present embodiment, when the paper is discharged, the discharge angle to the discharge tray is changed, the discharge angle is reduced with respect to the stacked paper, or the subsequent paper to be discharged is stacked. Since the contact time with the paper and the transport distance can be shortened, the stacked paper can be prevented from being pushed out. Therefore, even with paper with high friction or paper with large curl, it is possible to prevent stacking failure and paper dropping and improve alignment accuracy.
Also, paper discharge guide plate spacing, opening / closing operation, opening amount, and discharge angle can be set to post-processing mode (shift, binding presence / absence, binding type, folding, punching, single-sided / double-sided), paper size and type, etc. Since the paper discharge angle with respect to the paper discharge tray or the loaded paper surface can be controlled to the optimum angle depending on conditions such as thickness, weight, etc., it is possible to prevent stack failures and paper fall and improve alignment accuracy. it can.

  In addition, the said embodiment is an example of suitable implementation of this invention, and various deformation | transformation are possible for this invention, without being limited to this.

It is a figure which shows the structure of the paper post-processing apparatus which concerns on suitable embodiment of this invention. It is a figure which shows the mechanism which changes the discharge angle of a paper discharge guide plate. FIG. 6 is a diagram illustrating an operation mechanism below a paper discharge guide plate. It is a figure which shows the drive mechanism below a paper discharge guide plate. It is a figure which shows the operation | movement mechanism of a paper discharge guide plate upper side. It is a figure which shows the relationship between a discharge angle and the stacking | stacking property of a paper. It is a figure which shows the relationship between a discharge angle and the stacking | stacking property of a paper. It is a figure which shows the relationship between a discharge angle and the stacking | stacking property of a paper. It is a figure which shows the relationship between a discharge angle and the stacking | stacking property of a paper. It is a figure which shows the relationship between a discharge angle and the stacking | stacking property of a paper. It is a figure which shows the state which made the nip part contact a pair of discharge roller. FIG. 4 is a diagram illustrating a state where a gap is left in a nip portion of a pair of paper discharge rollers. It is a figure which shows the structure of the control system of a paper post-processing apparatus.

Explanation of symbols

100 Image forming apparatus 150, 250 Control unit 200 Post-processing apparatus 201 Entrance guide plate 202, 203, 204, 207a, 207b, 208, 209, 210, 212 Transport roller 211 Alignment tray discharge roller 213 Tapping roller 220, 221, 222 Transport path 222a First route 222b Second route 230, 231 Branch claw 232 Switching claw 241a Cam 241b Link 244 Shaft 251 Driver 261, 262, 263, 264, 265, 266, 267, 268, 303 Motor 304, 306, 309 Timing belt 305, 307 Pulley 308 Stepping motor 310 Rotating plate 310a Slit 311 Position detection sensor 401 Jogger 402 Tip stopper 403 Reference fence 404 Binding device 405 Alignment Ray 406 Release belt 406a Claw 502 Stack tray 502a Detection plate 803, 804 Paper amount sensor

Claims (12)

A paper post-processing device having a transport unit that transports a sheet output from the image forming apparatus, a sheet discharge unit that discharges the sheet out of the housing, and a stacking unit that stacks the discharged sheet.
The paper post-processing apparatus, characterized in that the paper discharge means includes means for changing a paper discharge angle at which the paper is discharged out of the housing and a plurality of paper discharge guide plates whose angles can be adjusted independently. .   The sheet post-processing apparatus according to claim 1, wherein the sheet discharge angle can be set to an arbitrary angle.   3. The sheet post-processing apparatus according to claim 1, wherein the discharge angle can be changed steplessly. It has a pair of discharge rollers for delivering the sheet to the outside of the housing, spacing of the discharge roller pair claim, wherein substantially constant der Rukoto irrespective of the opening angle the discharge guide plates are forms The sheet post-processing apparatus according to any one of 1 to 3. Wherein the plurality of angle of the sheet discharge guide plate is rotatably installed have sheet finisher of any one of claims 1, wherein 4 to Rukoto about the same or closely spaced axes. By setting the angle at which different said plurality of discharge guide plates, respectively, the paper post-processing of any one of claims 1 5, characterized in that a change in distance between the plurality of discharge guide plates apparatus. Wherein the plurality of discharge guide plate of the opening angle and the angle a sheet post-processing apparatus according to claim 6, optionally wherein the changeable der Rukoto. Depending on the nature of the paper, the paper post-processing apparatus according to any one of claims 1 to 7, wherein said sheet discharge means, characterized in that to change the angle of discharge of the sheet to the outside of the housing. In accordance with the specified operation mode by the image forming apparatus, a sheet post-processing apparatus of any one of claims 1 to 8, wherein that you change the paper ejection angle. 10. The post-sheet according to claim 1 , wherein the discharge angle is changed in accordance with the number of sheets on a stacking tray on which the sheets discharged by the discharge unit are stacked. Processing equipment. In accordance with the conveyance speed of the sheet, the sheet post-processing apparatus of any one of claims 1k et al 10, wherein Rukoto changing the discharge angle. An image forming apparatus comprising the sheet post-processing apparatus according to claim 1, either integrally or separately .

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