JP2014031244A - Sheet processing device and image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a sheet loaded on a processing tray from being pushed out by a buffer sheet.SOLUTION: A sheet processing device includes: a processing tray 29 on which a conveyed sheet is loaded; a buffer part which buffers the conveyed sheet to eject the sheet to the processing tray as a buffer sheet; and a sheet bundle carry-out part which moves while nipping the sheet loaded on the processing tray to eject the sheet from the processing tray. The sheet bundle carry-out part nips the sheet loaded on the processing tray when the buffer part ejects the buffer sheet.

Description

  The present invention relates to a sheet processing apparatus that processes a sheet and an image forming apparatus including the sheet processing apparatus.

  2. Description of the Related Art Conventionally, a sheet processing apparatus sequentially receives sheets formed with an image forming apparatus that forms an image on a sheet, aligns the end portions of the sheets into a bundle, and then binds the book. Some are post-processed such as processing and drilling.

  Such a sheet processing apparatus cannot discharge the sheet to be subjected to the next post-processing onto the processing tray while the post-processing is performed on the preceding sheet bundle on the processing tray (stacking unit). Therefore, until the post-processing of the preceding sheet bundle is completed and the sheet bundle moves from the processing tray to another stacking tray (receiving means), the image formation of the subsequent sheets must be interrupted and waited. There wasn't. As a result, there has been a problem that the speed of sheet post-processing cannot be increased and the productivity as a system is lowered.

  Therefore, conventionally, a sheet processing apparatus has been developed in which a buffer unit that temporarily stores (buffers) a sheet after image formation and waits until the post-processing of the preceding sheet is completed is arranged on the upstream side of the processing tray. (Patent Document 1). Such a sheet processing apparatus temporarily stores a subsequent image-formed sheet in a buffer unit while performing post-processing by bundling previously discharged sheets. The sheet processing apparatus discharges a plurality of sheets (buffer sheets) stored in the buffer unit onto the processing tray after the preceding sheet bundle finishes the post-processing and is discharged from the processing tray to the stacking tray. Further, subsequent sheets are also discharged, and when the desired number of sheets is reached, post-processing is performed. Thereby, when performing post-processing of a large number of sheet bundles, the sheet processing apparatus can efficiently and quickly perform post-processing of the sheet, and the productivity of the system can be improved.

Japanese Patent Laid-Open No. 2001-130828

  However, in the conventional sheet processing apparatus, when a plurality of sheets stored in the buffer unit are discharged to the processing tray, the top of the sheets stacked on the processing tray or the sheets stacked on the stacking tray It is conveyed while touching the sheet.

  At this time, since a plurality of sheets are discharged in a bundle, the sheets stacked on the processing tray or the stacking tray may be pushed out to cause a stacking failure.

  Further, an image forming apparatus provided with such a sheet processing apparatus forms an image again when the sheet stacked on the stacking unit is pushed out by the buffered sheet, falls, and is damaged. The image forming efficiency was low.

  The present invention provides a sheet processing apparatus in which sheets stacked on a stacking unit or a receiving unit are not pushed out by a plurality of buffered sheets, and an image forming apparatus including the sheet processing apparatus. become.

  The sheet processing apparatus of the present invention includes a stacking unit that stacks conveyed sheets, a holding unit that holds a plurality of conveyed sheets, and that transports a plurality of sheets to the stacking unit, and the stacking And a discharge means for discharging the sheet from the stacking means, while the holding means is transporting a plurality of sheets. The sheet stacked on the stacking means can be gripped.

  An image forming apparatus of the present invention includes: an image forming unit that forms an image on a sheet; and a sheet processing device that processes a sheet image-formed by the image forming unit, and the sheet processing device includes the sheet processing described above. It is a device.

  In the sheet processing apparatus according to the present invention, when a plurality of sheets held by the holding unit are being discharged, the discharging unit holds the sheets stacked on the stacking unit. Extrusion by a plurality of sheets can be prevented.

  The image forming apparatus according to the present invention includes the sheet processing apparatus that prevents the sheets stacked on the stacking unit from being pushed out by the plurality of sheets of the holding unit. It is not necessary to form the image, and the image forming efficiency can be increased.

1 is an overall configuration diagram of an image forming system according to the present invention. FIG. 2 is an overall configuration diagram of a sheet processing apparatus in the system of FIG. 1. FIG. 3 is an explanatory diagram of a main part of the sheet processing apparatus of FIG. 2. It is a configuration explanatory view of the rear end regulating means and alignment means of the processing tray. It is explanatory drawing of the discharge mechanism of a processing tray. (A) is explanatory drawing which shows the structure of a switchback roller pair. (B) is a figure which shows the standby state of a switchback roller pair. (C) is a diagram showing a sheet engagement state of a switchback roller pair. It is explanatory drawing of the aligning part and kicker part of a processing tray. (A) is explanatory drawing which shows the whole structure. (B) is a diagram showing a state where the number of sheets stacked is small. (C) is a diagram showing a state in which the number of sheets stacked is large. It is explanatory drawing of the kicker part of a processing tray. (A) is a figure which shows the positional relationship of a carrying-in guide and a carrying-out guide. (B) is a figure which shows the structure of a kicker part. (C) is a figure which shows the drive mechanism of a kicker part. FIG. 5 is a view when the side aligning portion in the processing tray aligns a large sized sheet at the center center, and is a view of FIG. 4 as viewed from below. FIG. 5 is a view when the side aligning portion in the processing tray aligns the middle-sized sheet at the center, and is a view when FIG. 4 is viewed from below. FIG. 5 is a view when the side aligning portion in the processing tray aligns a small-sized sheet at the center center, and is a view when FIG. 4 is viewed from below. FIG. 5 is a view when the side aligning portion in the processing tray performs offset alignment of a large size sheet, and is a view when FIG. 4 is viewed from below. It is a perspective view which shows the whole structure of a sheet bundle carrying-out part. It is explanatory drawing which shows the planar structure of a sheet bundle carrying-out part. It is explanatory drawing of the guide mechanism of a sheet bundle carrying-out part. It is explanatory drawing of the drive mechanism of a sheet bundle carrying-out part. It is explanatory drawing of the sheet gripping mechanism of a sheet bundle carrying-out part. (A) is the figure which showed the state which nipped the sheet | seat bundle. FIG. 6B is an explanatory diagram of a state where the nip of the sheet bundle is released. It is explanatory drawing of the sheet | seat gripping mechanism of a sheet bundle carrying-out part, and is explanatory drawing of the state which carried out the sheet bundle to the stack tray. It is an operation state explanatory view of a sheet bundle carrying-out part. (A) is a figure which shows the state in which a sheet | seat bundle carrying-out part is located in a 1st standby position. FIG. 8B is a diagram illustrating a state in which the rear ends of the sheet bundle are aligned. FIG. 10C is a diagram illustrating an initial state in which the sheet bundle carrying-out unit is retracted to the second standby position. (D) is a diagram showing a state in which the rear end of the sheet bundle is aligned in the state of (c). It is an operation state explanatory view of a sheet bundle carrying-out part. (A) is a figure which shows the state in which a sheet | seat bundle carrying-out part is located in a 2nd standby position. FIG. 6B is a diagram illustrating a state where the sheet bundle carrying-out unit nips the sheet bundle. FIG. 6C is a diagram illustrating a state where the sheet bundle carrying-out unit carries out the sheet bundle. It is an operation state explanatory view of a sheet bundle carrying-out part. (A) is a figure which shows the state which the sheet bundle carrying-out part transferred the sheet bundle on the stack tray. FIG. 6B is a diagram illustrating a state where the sheet bundle carrying-out unit carries the sheet bundle onto the stack tray. FIG. 10C is a diagram illustrating a state immediately after the sheet bundle carrying-out unit has stacked the sheet bundle on the stack tray. FIG. 6D is a diagram illustrating a state in which the sheet bundle carry-out unit has returned to the first standby position. It is a figure which shows tray tray outlet periphery. (A) is a figure which shows a safety mechanism. (B) is the AA sectional view. It is a figure of a safety mechanism different from the safety mechanism shown in FIG. It is a figure which shows the raising / lowering mechanism of a stack tray, and an arm lever. It is a figure which shows the raising / lowering state of a stack tray. FIG. 6A is a diagram illustrating a state in the middle of stacking sheets from the first transport path to the stack tray. FIG. 6B is a diagram illustrating a state in which sheets are stacked on the processing tray from the first conveyance path. (C) is a diagram showing a state in which a sheet bundle is carried out from the processing tray onto the stack tray. It is a control block diagram of an image forming system. It is a figure which shows a buffer part and a buffer discharge part. It is a figure for operation | movement description with a buffer part and a buffer discharge | emission part. FIG. 28 is a diagram for explaining operations of the buffer unit and the buffer discharge unit following FIG. 27. FIG. 28 is a view of a sheet curled by the buffer path shown in FIG. 27. FIG. 10 is a diagram in a case where a shift occurs between sheets when a sheet is discharged from a conveyance path to a processing tray. It is a figure which shows the state in which the sheet | seat bundle carrying-out part has received several sheets (buffer sheet) on the stack tray. FIG. 32 is a diagram illustrating an operation state of the sheet bundle carrying-out unit following FIG. 31. It is a figure which shows the operation state of the sheet | seat bundle carrying-out part following FIG. It is a flowchart for operation | movement description of a sheet bundle carrying-out part (especially sheet gripping mechanism).

  Hereinafter, an image forming system according to an embodiment of the present invention will be described. The main part of the present invention is described at the end of the embodiment. Moreover, the numerical value taken up is a reference numerical value, and is not a numerical value that limits the present invention. 1 is an overall configuration diagram showing an image forming system C including an image forming apparatus A and a sheet processing apparatus B according to the present invention, FIG. 2 is an explanatory diagram of a detailed configuration of the sheet processing apparatus B, and FIG. It is explanatory drawing of the principal part.

[Configuration of Image Forming System C]
An image forming system C shown in FIG. 1 includes an image forming apparatus A and a sheet processing apparatus B. The image forming system C is configured by connecting the sheet carry-in port 23a of the sheet processing apparatus B to the paper discharge port 3 of the image forming apparatus A. In the image forming system C, the sheet on which the image is formed by the image forming apparatus A is stapled or aligned by the sheet processing apparatus B and discharged to the stack tray 21 and the saddle tray 22.

[Configuration of Image Forming Apparatus A]
The image forming apparatus A will be described with reference to FIG. In the image forming apparatus A, a sheet is sent from the paper feeding unit 1 to the image forming unit 2, printed on the sheet by the image forming unit 2, and then discharged from the paper discharge port 3.

  The sheet feeding unit 1 stores sheets of a plurality of sizes in sheet feeding cassettes 1 a and 1 b, separates the designated sheets one by one and feeds them to the image forming unit 2. In the image forming unit 2, a photosensitive drum 4, a print head (laser light emitter) 5, a developing device 6, a transfer charger 7, and a fixing device 8 are arranged around the photosensitive drum 4. The image forming unit 2 forms an electrostatic latent image on the photosensitive drum 4 with a laser light emitter 5, and attaches toner to the developer drum 6 to form a toner image. Then, the image forming unit 2 transfers the image onto the sheet by the transfer charger 7 and heat-fixes the sheet by the fixing device 8 to fix the toner image. The sheets on which images are formed in this way are sequentially carried out from the paper discharge port 3. The circulation path 9 is a double-sided printing path in which a sheet printed on the front side from the fixing device 8 is turned upside down via the switchback path 10 and then fed again to the image forming unit 2 and printed on the back side of the sheet. It is. As described above, the double-sided printed sheet is turned upside down by the switchback path 10 and then carried out from the paper discharge port 3.

  The image reading device 11 scans a document sheet set on the platen 12 with a scan unit 13 and electrically reads it with a photoelectric conversion element (not shown). The image data is digitally processed, for example, by the image processing unit, then transferred to the data storage unit 14 and sent to the laser emitter 5 as an image signal. The document feeder 15 is a feeder device that feeds document sheets stored in the stack tray 16 to the platen 12.

  The image forming apparatus A is provided with an image forming apparatus control unit 150 (FIG. 25). Image forming conditions such as sheet size designation, color / monochrome printing designation, number of copies designated, single-sided / double-sided printing designation, enlarged / reduced printing designation, etc. are set from the control panel 18 (FIG. 25) of the image forming apparatus A. The On the other hand, in the image forming apparatus A, image data read by the scan unit 13 or image data transferred from an external network is accumulated in the data storage unit 17. Image data is transferred from the data storage unit 17 to the buffer memory 19, and data signals are sequentially transferred from the buffer memory 19 to the laser emitter 5.

  From the control panel 18, post-processing conditions are also input and designated simultaneously with the image forming conditions such as single-sided / double-sided printing, enlargement / reduction printing, and monochrome / color printing described above. As the post-processing conditions, for example, “print-out mode”, “binding finishing mode”, “booklet finishing mode”, and the like are selected.

[Configuration of Sheet Processing Apparatus B]
The sheet processing apparatus B receives a sheet on which an image has been formed from the paper discharge port 3 of the image forming apparatus A, and (i) accommodates the sheet in the stack tray 21 (the aforementioned “print-out mode”). . Further, the sheet processing apparatus B is configured to (ii) align the sheets from the sheet discharge outlet 3 in a bundle and staple them, and then store them in the stack tray (first stack tray) 21 (described above). "Binding mode"). Further, the sheet processing apparatus B (iii) aligns the sheets from the sheet discharge outlet 3 in a bundle shape, staples the center of the sheet, folds it into a booklet, and stores it in a saddle tray (second stack tray) 22. ("Booklet finishing mode" described above).

  In FIG. 1, the sheet moves from the right to the left when guided along the first conveyance path K1, and therefore, the left end is the leading end and the right end is the trailing end. However, when the sheets are stacked on the processing tray 29 and move to the sheet end regulating portion 32, the sheets move from the left to the right, so that the right end is the leading end and the left end is the trailing end. As described above, the leading edge and the trailing edge of the sheet change depending on the conveyance direction. Therefore, for convenience of explanation, with regard to the leading edge and leading edge portion, the trailing edge, and the trailing edge portion of the sheet, regardless of whether the sheet is located on the first conveyance path K1, the processing tray 29, or the stack tray 21, FIG. In FIG. 2, let the left end be a front end and a front end, and the right end be a rear end and a rear end.

  The casing (exterior cover) 20 of the sheet processing apparatus B is provided with a sheet carry-in port 23 a, and the sheet carry-in port 23 a is connected to the paper discharge port 3 of the image forming apparatus A. Then, in the casing 20, the first processing unit BX1 that aligns and stacks the sheets from the sheet carry-in port 23a and finishes the binding, and the second process that completes and stacks the sheets from the sheet carry-in port 23a and finishes the booklet. Part BX2 is provided. A first conveyance path K1 is provided between the first processing unit BX1 and the sheet carry-in port 23a, and a second conveyance path K2 is provided between the second processing unit BX2 and the sheet carry-in port 23a. The sheet carry-in entrance 23a is provided with a carry-in roller 23, a sheet sensor S1, and a path switching member 24 that distributes the sheets to the first or second conveyance paths K1 and K2. The path switching member 24 distributes and guides the sheet from the sheet carry-in port 23a to the first processing unit BX1 and the second processing unit BX2.

  A buffer path K3 is provided between the punch unit 60 and the processing tray 29 in the first transport path K1. The buffer path K3 temporarily retains subsequent sheets sent to the sheet carry-in port 23a during the post-processing operation when post-processing such as stapling is performed on the sheet bundle that has been aligned and accumulated on the processing tray 29. It is like that. Therefore, the buffer path K3 is branched and arranged in the first conveyance path K1 in the vertical direction of the casing 20 on the upstream side of the path to the processing tray 29 as shown in FIG. The buffer path K3 can retain the switchback sheet from the first transport path K1. Therefore, the buffer path K3 can temporarily retain the subsequent sheet sent to the carry-in port when post-processing (end stitching processing described later) is performed on the sheet bundle that has been aligned and accumulated on the processing tray 29. . The sheets in the buffer path K3 are transferred to the processing tray 29 after the processed sheet bundle in the processing tray 29 is unloaded.

  The first transport path K1 is disposed substantially horizontally in the upper part of the apparatus housing constituted by the casing 20, and the first processing unit BX1 is disposed downstream of the first transport path K1, and the stack tray 21 is disposed downstream thereof. Is arranged. The second transport path K2 is disposed substantially vertically in the lower portion of the casing 20, the second processing unit BX2 is disposed on the downstream side of the second transport path K2, and the saddle tray 22 is disposed on the downstream side thereof. Has been. In the first transport path K1, the punch unit 60 is disposed between the sheet carry-in port 23a and the first processing unit BX1. A trimmer unit 90 is arranged between the second processing unit BX2 and the saddle tray 22 in the second transport path K2.

  The first transport path K1 is provided with a pair of paper discharge rollers 25 and a paper discharge port 25x at the path exit end, and a paper discharge sensor S2 is disposed in the paper discharge port 25x. The paper discharge sensor S2 detects a sheet passing through the first transport path K1, detects the jam, and counts the number of sheets passed. A processing tray 29 is disposed with a step formed downstream of the paper discharge port 25x. In addition, a conveyance roller 27 is provided in the second conveyance path K2, and a stacking guide 45, which will be described later, is disposed with a step formed on the downstream side thereof.

[Configuration of the first processing unit BX1]
The first processing unit BX1 (FIGS. 2 and 3) includes a processing tray 29 disposed on the first transport path K1, an end binding stapler unit 31 disposed on the processing tray 29, and an aligning unit 51. Has been.

[Structure of processing tray 29]
The processing tray 29 serving as a stacking unit on which the conveyed sheets are stacked is formed of a synthetic resin plate or the like, and includes a sheet support surface 29a for stacking and supporting the sheets. The sheet support surface 29a is disposed with a step formed downstream of the paper discharge port 25x, and is configured to stack sheets from the paper discharge port 25x. The sheet support surface 29a is formed to have a length shorter than the length in the sheet discharge direction, and supports the rear end portion of the sheet from the sheet discharge port 25x. In this case, the leading end of the sheet is supported (bridge supported) on the uppermost sheet of the stack tray 21.

  The processing tray 29 is provided with a sheet end regulating portion 32. The sheet end regulating portion 32 receives and aligns the sheet rear end from the sheet discharge outlet 25x. 3 includes a fixed stopper 32A that is fixed at the center in the sheet width direction, and left and right movable stoppers 32C and 32B that are movable in the left and right directions at the width direction end portions (left and right end portions of the sheet). It consists of These stoppers are arranged at a predetermined interval, and are formed by a plurality of stopper members described later.

  Above the processing tray 29, a switchback roller pair 26 (movable roller 26 a and driven roller 26 b) that transfers a sheet carried on the processing tray 29 to the sheet end regulating unit 32, an aligning unit 51, and a side A matching unit 34 is arranged. Each configuration will be described below.

[Configuration of Sheet Edge Restricting Unit 32]
The processing tray 29 is provided with a sheet end regulating portion 32 that positions the trailing end of the loaded sheet. Each of the stoppers 32A, 32B, and 32C constituting the sheet end regulating portion 32 shown in FIG. 4 includes a sheet end surface regulating surface 32a that receives and regulates the trailing edge of the sheet, and a sheet upper surface that regulates the upper surface of the uppermost sheet. It is formed with the regulation surface 32b. The sheet end regulating portion 32 is disposed at the rear end edge of the processing tray 29, receives and regulates the rear end edge of the sheet transferred by the switchback roller pair 26 and the aligning portion 51, which will be described later, and is set in advance. The sheet is positioned at a post-processing position (binding position; the same applies hereinafter). At this time, the sheet upper surface regulating surface 32b regulates the warping surface of the sheet with the trailing end curled, and the sheet edge surface regulating surface 32a regulates the position of the sheet edge.

  The sheet end surface regulating surface 32a and the sheet upper surface regulating surface 32b are integrally formed of a resin, a metal plate, or the like, and both the regulating surfaces can be formed of individual members. The leaf spring 32s is attached to the fixed stopper 32A, the left movable stopper 32C, and the right movable stopper 32B in order to correct the curl at the trailing edge of the sheet.

  As described above, the left and right movable stoppers 32C and 32B positioned at the left and right ends of the sheet are moved according to the sheet size. Therefore, the left slide member 38b and the right slide member 38a are fitted and supported on the bottom wall of the processing tray 29 so as to be movable in the sheet width direction. A right movable stopper 32B and a left movable stopper 32C are fixed to the left and right slide members 38b, 38a. The left and right slide members 38b and 38a are connected to interlock with a left side alignment plate 34L and a right side alignment plate 34R that align the seat sides as will be described later.

  Each stopper 32A, 32B, 32C of the sheet end regulating portion 32 is configured such that at least the sheet upper surface regulating surface 32b can be moved up and down in the sheet stacking direction. When the sheet bundle on the processing tray 29 is unloaded from the processing tray 29 by the sheet bundle unloading unit 100 described later, the sheet bundle on the tray 29 may be lifted upward by the sheet bundle unloading unit 100. Therefore, the sheet upper surface regulating surface 32b can be moved upward following the upward movement of the sheet bundle.

  Therefore, as shown in FIG. 4, the fixed stopper 32 </ b> A is pivotally supported by the bottom wall of the processing tray 29 so as to be swingable, and is urged and supported by the urging spring 33 downward in the drawing. The first and second movable stoppers 32B and 32C are attached to the left and right slide members 38b and 38a so as to be elastically deformable (portions indicated by reference numeral 32α).

[Configuration of Switchback Roller Pair (Sheet Transfer Unit) 26]
In the processing tray 29 (FIG. 3), a switchback roller pair 26 for guiding the sheet carried in from the sheet discharge outlet 25x to the sheet end regulating portion 32 is disposed. The switchback roller pair 26 is constituted by a friction rotating body such as a roller and a belt for transferring a sheet conveyed to the processing tray 29 from the sheet discharge outlet 25x to the sheet end regulating portion 32.

  As shown in FIG. 5, the switchback roller pair 26 is disposed above the processing tray 29 and conveys the uppermost sheet P on the processing tray 29 in the forward and reverse directions. The movable roller 26a of the switchback roller pair 26 has an operating position (FIG. 5C) in contact with the sheet on the processing tray 29, and a standby position spaced above the sheet (FIG. 5B). Are supported by the lift support arm 28 so as to move up and down. That is, the lifting / lowering support arm 28 is supported by an apparatus frame (not shown) so as to be swingable by a swinging rotary shaft 28a, and the swinging rotary shaft 28a is connected to a lift motor MY via a pinion 28p. . Note that a position sensor (not shown) is disposed on the lifting support arm 28. The position sensor detects the position of the lifting support arm 28 so that the movable roller 26a can move up and down between the standby position and the operating position.

  The movable movable roller 26a that is axially supported by the elevating support arm 28 is rotated forward and backward by a forward / reverse motor (not shown), and the sheet carried on the processing tray 29 is conveyed forward and backward in the paper discharge direction and in the opposite direction. It is supposed to be. Therefore, the roller rotation shaft 26z of the movable roller 26a is supported by a long groove 28u formed in the lift support arm 28 as shown in FIG. 5A, and can move up and down in the sheet stacking direction (vertical direction in FIG. 5A). It is supported by the shaft. The movable roller 26a on the movable side is provided with a paper surface contact sensor Ss. The leaf spring 28z constantly biases the roller rotation shaft 26z downward, and the shaft is lifted when the movable roller 26a is lowered to prevent malfunction of the paper surface contact sensor Ss.

“Paper contact sensor Ss”
The lift support arm 28 is provided with a paper surface contact sensor Ss for detecting the position of the roller rotation shaft 26z of the movable roller 26a that moves up and down along the long groove 28u. The paper surface contact sensor Ss detects the position of the roller rotation shaft 26z that moves (moves upward) in the long groove 28u by the contact pressure at which the movable roller 26a contacts the uppermost sheet on the processing tray. For this reason, the lift support arm 28 is provided with a sensor lever 30 having a rotation center o1 at a position different from the swing rotation shaft 28a, and a roller rotation shaft 26z is axially coupled to the tip of the sensor lever 30. The sensor flag 30f formed at the rear end of the sensor lever 30 is detected by the paper surface contact sensor Ss. The paper surface contact sensor Ss is a photo sensor. Such a movable roller 26a swings the lifting support arm 28 up and down by the lifting motor MY, thereby contacting the standby position above the processing tray (FIG. 5B) and the sheet carried on the processing tray. It moves up and down between the positions (FIG. 5C). Then, the paper surface contact sensor Ss disposed on the elevating support arm 28 detects that the movable roller 26a of the switchback roller pair 26 contacts the sheet carried on the processing tray 29.

“Configuration of Control Unit 165”
The control unit 165 (FIG. 25) that controls the lift motor MY is configured as follows. The control unit 165 is incorporated in a control CPU 161, which will be described later, and controls to raise and lower the elevation support arm 28 to a standby position and an operation position. The control unit 165 is stopped at a standby position by a position sensor (not shown) disposed on the elevating support arm 28. Then, the control unit 165 detects the leading edge of the sheet carried out from the paper discharge port 25x by the paper discharge sensor S2, and displays the lifting motor MY after a predetermined time after the front edge of the sheet passes directly below the paper discharge sensor S2. 5 (a) is rotated counterclockwise. Then, the elevating support arm 28 rotates in the counterclockwise direction of FIG. 5A around the swing rotation shaft 28a. As a result, the roller rotating shaft 26z of the movable roller 26a is supported by the long groove 28u, so that the operating position (FIG. 5 (c)) is changed from the standby position (FIG. 5 (b)) at substantially the same speed as the lifting support arm 28. To descend. At this time, the sensor lever 30 connected to the movable roller 26a also moves (lowers) in the same direction at the same speed as the lifting support arm 28.

  The control unit 165 sets the lowering speed (rotational speed of the lifting motor MY) Va of the lifting support arm 28 to be equal to or higher than the speed (free falling speed) Vr at which the movable roller 26a on the movable side falls within the long groove 28u by its own weight. It is set to be slow (Va ≦ Vr). This is to prevent the sheet contact sensor Ss from malfunctioning due to rebound or the like when the descending speed Va of the elevating support arm 28 is made faster than the movable roller 26a that freely falls in the long groove 28u and the movable roller 26a becomes unstable. . That is, erroneous detection such as chattering of the paper surface contact sensor Ss is prevented by limiting the speed Vr at which the movable roller 26a falls by the speed of the elevating support arm 28 and gradually lowering it.

  Next, when the peripheral surface of the movable roller 26a abuts on the uppermost sheet on the processing tray 29, the movable roller 26a of the switchback roller pair 26 stops on the uppermost sheet, but the lifting support arm 28 continues swinging in the same direction. At this time, the sensor lever 30 swings clockwise (in the direction indicated by the arrow in FIG. 5C) about the central rotation center o1. Then, the paper surface contact sensor Ss detects the sensor lever 30 and is turned “ON”. The raising / lowering motor MY stops by the detection signal of the paper surface contact sensor Ss. As a result, the movable roller 26a always comes into contact with the uppermost sheet with a constant pressure contact force (for example, its own weight) Pt regardless of the amount of sheets stacked on the processing tray 29 (FIG. 5C). )reference).

  Concurrently with the lowering of the switchback roller pair 26 to the operating position, the control unit 165 drives a forward / reverse motor (not shown) to rotate the movable roller 26a forward and backward. Then, the sheet carried on the uppermost sheet on the processing tray 29 from the sheet discharge outlet 25x receives a certain conveyance force and is transferred in the sheet discharge direction and the sheet discharge opposite direction. The movable roller 26 a rotates clockwise when the sheet is conveyed from the sheet discharge outlet 25 x in the sheet discharge direction, and pulls the trailing end of the sheet into the processing tray 29. Then, the movable roller 26a rotates reversely after the trailing edge of the sheet has passed through the sheet discharge outlet 25x, and is transported back to the sheet edge regulating portion 32 side. During this sheet conveyance process, the sheet and the movable roller 26a contact the uppermost sheet with a constant pressing force regardless of the number of sheets stacked on the processing tray, and apply a preset predetermined conveyance force to the sheet. become.

"Aligning part 51"
On the processing tray 29, an aligning unit 51 that transfers the sheet to the sheet end regulating unit 32 together with the switchback roller pair 26 is provided. As shown in FIG. 6A, the aligning unit 51 is disposed immediately below the sheet discharge outlet 25x, and scrapes the rear end of the sheet carried into the processing tray 29 toward the sheet end regulating unit 32. For example, a friction rotating body 52 serving as an aligning rotating body is provided.

  The friction rotating body 52 is a rotating body such as a roller or a belt made of rubber or sponge (porous foam), contacts the uppermost sheet on the processing tray 29, and causes the sheet to move in a predetermined direction by the friction force. To be transferred to. The friction rotating body 52 moves up and down in accordance with the number of sheets stacked on the processing tray 29. For this reason, a friction rotating body (roller) 52 is supported by a bearing on an elevating support arm 54 that is pivotally supported by a swing rotation shaft 53 on an apparatus frame (not shown). A driving pinion 53p is attached to the oscillating rotating shaft 53, and a stepping motor MC is connected to the driving pinion 53p. A torque limiter (not shown) is built in between the drive pinion 53p and the swing rotation shaft 53. Therefore, when the friction rotating body 52 attached to the lifting / lowering support arm 54 comes into contact with the uppermost sheet on the processing tray 29, the torque limiter idles due to the reaction force, and the friction rotating body 52 always moves to the uppermost sheet with a constant pressure. It comes to contact.

  Therefore, the elevating support arm 54 stops at a position where the friction rotating body 52 is in contact with the uppermost sheet regardless of the number of stacked sheets stacked on the processing tray 29. After the elevating support arm 54 stops on the uppermost sheet, a torque limiter (not shown) idles and applies a predetermined pressing force to the friction rotating body 52. Note that an idle pulley is supported on the swing rotation shaft 53, and a drive motor (not shown) is connected to the pulley. The rotational force of the drive motor is transmitted from the pulley to the friction rotator 52 with a belt or the like. Accordingly, the friction rotator 52 rotates counterclockwise in FIG. 6 at the operation position shown in FIGS. 6B and 6C and directs the sheet carried on the processing tray 29 toward the sheet end regulating portion 32. It is designed to be transported.

  The elevating support arm 54 is provided with a carry-in guide 54 a on the upstream side of the friction rotating body 52, and a carry-out guide 54 b facing the downstream side is rotatably attached. The carry-in guide 54 a is formed in a guide shape for guiding the trailing end of the sheet to the friction rotating body 52. The carry-out guide 54 b is located between the friction rotator 52 and the sheet end regulating portion 32, and is formed in a guide shape that guides the rear end of the sheet to the sheet end regulating portion 32.

"Import guide 54a"
As shown in FIG. 6A, the carry-in guide 54a is formed integrally with the lifting support arm 54, and the sheet carry-in side is high in friction rotation so as to guide the rear end of the sheet in the circumferential direction of the friction rotating body 52. A tapered surface 54a1 is formed so as to be lowered on the body side. Therefore, even if the trailing edge of the sheet sent toward the sheet edge regulating portion 32 by the switchback roller pair 26 is curled and warped, the trailing edge of the sheet is directed to the friction rotating body 52 along the tapered surface 54a1. You will be guided. Further, since the carry-in guide 54a is integrally formed with the lifting support arm 54, the carry-in guide 54a is lifted upward according to the number of sheets stacked on the processing tray. If the friction rotating body 52 is reduced in size by reducing the diameter of the friction rotating body 52, the sheet with the curled rear end may be caught in the friction rotating body 52 and jammed. Therefore, when the trailing edge of the sheet is guided by the carry-in guide 54a, the angular relationship between the tapered surface 54a1 and the roller peripheral surface changes according to the number of stacked sheets, thereby causing a jam. In order to solve such a problem, the friction rotating body 52 and the carry-in guide 54a are integrated to move up and down according to the number of stacked sheets.

"Unloading guide 54b"
The carry-out guide 54 b includes a guide surface 54 b 1 that guides the rear end side of the sheet fed by the friction rotating body 52 from above and guides it to the sheet end regulating portion 32. The carry-out guide 54 b is rotatably provided on the lifting support arm 54 coaxially with the friction rotating body 52. Accordingly, the sheet can be moved upward according to the number of sheets stacked on the processing tray.

  However, the carry-in guide 54 a is restricted from rotating in the direction approaching the processing tray 29. For this reason, as shown in FIG. 7A, the carry-in guide 54a has an interval (L1) between the carry-in guide 54a and the uppermost sheet as compared with an interval (L2) between the carry-out guide 54b and the uppermost sheet. Large (L1> L2) is set.

"Configuration of kicker section 55"
The carry-in guide 54 a is configured to guide the sheet from the paper discharge port 25 x to the friction rotating body 52 in cooperation with the kicker portion 55 disposed on the upstream side. The kicker unit 55 will be described. A step is formed between the paper discharge outlet 25 x and the processing tray 29. For this reason, the trailing edge of the sheet sent by the switchback roller pair 26 from the paper discharge outlet 25 x falls on the processing tray 29. Therefore, a kicker portion 55 is provided at the paper discharge outlet 25x.

  As shown in FIG. 6A, the kicker portion 55 includes a base end swing lever 55a attached to the apparatus frame by a rotating shaft 56, a kick lever 55b, and the like. A drive motor MK is connected to the rotation shaft 56 of the base end swing lever 55a by a gear. A kick lever 55b is pivotally connected to the distal end of the base end swing lever 55a. 7A and 7C, the rotating shaft 56 is rotated by the drive motor MK, and the shaft fulcrum 55b1 of the kick lever 55b is connected to the rotating shaft 56 via a gear and a belt. It is connected. The base end swing lever 55a of the kicker portion 55 at the broken line position (standby position) in FIG. 7B swings in the direction indicated by the arrow a (counterclockwise) when the drive motor MK is rotated clockwise in FIG. To do. At this time, since the kick lever 55b is connected to the rotating shaft 56, the gear, and the belt, the kick lever 55b rotates in the direction of arrow b (clockwise) in FIG. Accordingly, when the drive motor 57 is rotated forward (clockwise in the drawing), the kicker portion 55 is rotated from the broken line state to the solid line state in FIG. 7B and discharged from the discharge port 25x. The rear end is pressed onto the lower processing tray 29.

  The control CPU 161 (FIG. 25) is a detection signal that the rear end of the sheet has passed through the paper discharge sensor S2 of the paper discharge port 25x, and the drive motor 57 is matched with the timing at which the rear end of the sheet passes the paper discharge roller pair 25. The kicker 55 kicks the trailing edge of the sheet onto the tray. The sheet dropped by the kicker section 55 is conveyed to the sheet end regulating section 32 side by the movable roller 26a of the switchback roller pair 26, guided by the carry-in guide 54a, and sent to the friction rotating body 52.

[Configuration of Left Side Alignment Plate 34L and Right Side Alignment Plate 34R]
The processing tray 29 is provided with left and right side alignment plates 34L and 34R for aligning and aligning sheets (FIGS. 4, 8, 9, 10, and 11). The side aligning unit 34 aligns the sheets carried into the processing tray 29 from the paper discharge outlet 25x with reference to the center (width center) CL of the sheet and the left and right side edges of the sheet as a reference. One of the side references to be aligned is adopted. Description will be made based on the perspective view shown in FIG. 4 and the operation state diagrams shown in FIGS.

  As shown in FIG. 4, the side aligning portion 34 includes a left side aligning plate 34L that abuts on the left edge of the sheet on the processing tray 29 and a right side aligning plate 34R that abuts on the right edge of the sheet. . The left and right side alignment plates 34L and 34R are fitted and supported in alignment plate grooves 29b (see FIG. 4) formed in the sheet support surface 29a of the processing tray 29, respectively, and can be moved in the sheet width direction. ing. The width direction of the sheet is a direction orthogonal to the direction in which the sheet moves on the processing tray 29. As shown in FIG. 8, a pair of pulleys 35 is disposed on the bottom of the processing tray 29 along the alignment plate groove 29b (FIG. 4), and a belt 36 is bridged over the pair of pulleys 35. The left and right side alignment plates 34L and 34R are fixed to the belt 36. Further, shift motors MZ1 and MZ2 are connected to one of the pulleys 35.

  The left side alignment plate 34L and the right side alignment plate 34R move in the sheet width direction (left and right in the drawing) by driving the respective shift motors MZ1, MZ2. Therefore, the left and right shift motors MZ1, MZ2 are synchronously rotated in the opposite direction by the same amount, so that the sheets carried on the processing tray 29 can be aligned with the center reference. FIG. 8 shows a state in which a large size sheet is width aligned, and FIG. 9 shows a state in which a medium size sheet is width aligned. FIG. 10 shows a state where a small size sheet is width-aligned. On the other hand, the sheet bundle aligned on the processing tray 29 on the center basis can be offset by rotating the left and right shift motors MZ1, MZ2 in the same direction by the same amount. FIG. 11 is a diagram illustrating a case where a large-size sheet is offset. Thus, offsetting a large-size sheet by a predetermined amount requires that the post-processing apparatus be moved to the side of the apparatus when the post-processing position is biased toward the sheet corner (corner staple described later), which increases the size of the apparatus. Bring. Thus, post-processing such as corner binding can be performed by offsetting the sheet bundle accumulated on the processing tray 29 by a predetermined amount. This achieves a compact and compact device.

[Interlocking mechanism between left and right side alignment plates 34L, 34R and movable stoppers 32C, 32B]
The left and right side alignment plates 34L and 34R are interlocked with the sheet end regulating portion 32 as follows. The sheet end regulating portion 32 includes a fixed stopper 32A, a right movable stopper 32B, and a left movable stopper 32C. The left and right movable stoppers 32C and 32B are connected to left and right slide members 38b and 38a that are fitted and supported on the processing tray 29 so as to be movable in the sheet width direction.

  The left and right movable stoppers 32C and 32B are coupled to the left and right side alignment plates 34L and 34R by a coupling spring 37 as shown in FIG. That is, the right slide member 38a having the right movable stopper 32B is connected by the connecting spring 37a, and the left slide member 38b having the left movable stopper 32C is connected by the connecting spring 37b. The left and right side alignment plates 34L, 34R reciprocate between the strokes LS1 in the sheet width direction. On the other hand, the left and right movable stoppers 32C and 32B are driven between the strokes LS2. For this reason, stop members (not shown) are arranged on the processing tray 29 side in the left and right movable stoppers 32C and 32B.

  The strokes LS1 and LS2 are set such that LS1> LS2, and the left and right movable stoppers 32C and 32B move by the same amount until they abut against this stop member in conjunction with the movement of the left and right side alignment plates 34L and 34R. The movable stoppers 32B and 32C abut against the stop member and then stop at the position of the stop member, but the left and right side alignment plates 34L and 34R further move. At this time, the connecting springs 37a and 37b connecting the two extend (extend). Therefore, the left and right side alignment plates 34L and 34R move between strokes LS1 corresponding to the sheet size, and the movable stoppers 32B and 32C move between strokes LS2. Thus, the reason why the strokes of the left and right movable stoppers 32C and 32B are set short is that a sheet bundle carrying-out portion 100 described later is disposed at the center of the sheet.

  As described above, when the left and right movable stoppers 32C and 32B constituting the sheet end regulating portion 32 are interlocked with the side aligning portion 34 and the movement strokes of the both are made different, the embodiment using the connection spring 37 has been described in the illustrated embodiment. . However, the left and right side alignment plates 34L and 34R and the left and right movable stoppers 32C and 32B may use a sliding transmission mechanism or a deceleration transmission mechanism.

  In the case of a sliding transmission mechanism, the left and right side alignment plates 34L and 34R and the left and right movable stoppers 32C and 32B are connected by a sliding friction clutch, and the clutch plates slide after the left and right movable stoppers 32C and 32B hit the stop member. Configured to exercise. In the speed reduction transmission mechanism, the left and right side alignment plates 34L and 34R and the left and right movable stoppers 32C and 32B are connected by a gear transmission mechanism. The gear ratio of the speed reduction transmission mechanism is set so that the left and right side alignment plates 34L and 34R move with the stroke LS1, and the movable stoppers 32B and 32C move with the stroke LS2.

  Control of the side alignment unit 34 will be described. The left and right side alignment plates 34L and 34R are provided with position sensors at preset home positions, and the left and right side alignment plates 34L and 34R are positioned at the home position when the apparatus is activated. The control CPU 161 (FIG. 25) receives the size information of the sheet on which the image is formed from the image forming apparatus A, and based on this information, the control unit 166 positions the left and right side alignment plates 34L and 34R at predetermined standby positions. . This standby position is set to a position (a position for forming an alignable moving width) that is a predetermined amount away from the width size of the sheet sent to the processing tray 29. Therefore, the control CPU 161 turns the left and right shift motors MZ1 and MZ2 in the opposite directions after the expected time that the trailing edge of the sheet unloaded from the sheet discharge outlet 25x is loaded onto the processing tray (after the timer time has elapsed from the sheet discharge sensor S2). In synchronization with each other by a predetermined amount. Then, the sheets carried onto the processing tray 29 are aligned in the width direction by the left and right side alignment plates 34L and 34R.

"Corner staple mode"
The post-processing control unit 160 (FIG. 25) moves the left and right side alignment plates 34L and 34R by a predetermined amount in the sheet width direction when binding a bundle of sheets that are aligned and stacked on the processing tray by the stapler unit 31 described later. And offset it. This is because when the stapler unit 31 is moved to this position when binding the sheet corner, the sheet processing apparatus B becomes larger in the sheet width direction. Therefore, the sheet processing apparatus B of the present embodiment can offset the sheet bundle on the processing tray by driving the shift motors MZ1, MZ2 of the left and right side alignment plates 34L, 34R in the same direction by the same amount in the corner staple mode. It has become.

[Configuration of Sheet Bundle Unloading Unit 100]
The processing tray 29 is provided with a sheet bundle unloading unit 100 for unloading the processed sheet bundle to the downstream stack tray 21 (FIG. 1). 12 is an external perspective view of the sheet bundle carrying-out unit 100, FIG. 13 is an explanatory view showing a planar configuration, FIG. 14 is an explanatory view of a guide mechanism, FIG. 15 is an explanatory view of a drive mechanism, and FIG. It is explanatory drawing of the sheet | seat gripping mechanism of a carrying-out part. The sheet bundle carrying-out unit 100 is disposed at the bottom of the processing tray 29, and mainly protrudes above the sheet support surface 29a to hold the sheet bundle, and a carrier on which the sheet holding mechanism 105 is mounted and supported. It is comprised with the member 110. FIG.

  As shown in FIGS. 12 and 16, the sheet bundle carrying-out unit 100 includes a sheet gripping mechanism 105 and a carrier member 110, a gripping mechanism driving unit 127 (FIG. 16), and a carrier driving unit 114. The sheet gripping mechanism 105 includes a movable gripper 105a and a fixed gripper 105b. Further, the carrier member 110 is mounted with the sheet gripping mechanism 105 and is configured to reciprocate from the proximal end portion (post-processing position) of the processing tray 29 to the distal end portion (bundle unloading position). Each configuration will be described below.

"Sheet gripping mechanism 105"
The sheet gripping mechanism 105 is constituted by a protruding piece, a gripper, or the like that grips the rear end edge of the sheet bundle stacked on the processing tray, and a guide groove 29G (FIG. 13) formed on the sheet support surface 29a of the processing tray 29. Is placed inside. As shown in FIG. 13, a guide groove 29G is formed in the processing tray 29 between the processing position and the stack tray 21 (FIGS. 1 to 3) arranged on the downstream side of the processing tray 29 in the sheet bundle carrying-out direction. Is formed. The guide groove 29G is formed with two guide grooves 29G1, 29G2 at a distance in the sheet width direction, and the sheet gripping mechanism 105 is disposed in each of the right and left guide grooves 29G1, 29G2 as follows.

  The sheet gripping mechanism 105 is a so-called gripper mechanism that grips and carries out the trailing edge of the sheet bundle on the processing tray 29. As shown in FIGS. 12 and 16, the movable gripper 105a and the fixed gripper 105b are connected to each other by a pivot pin (connection shaft) 106 (FIG. 16) so as to approach and separate from each other. A biasing spring 107 (FIG. 16) is provided between the movable gripper 105a and the fixed gripper 105b. The tip nip portion 105ax of the movable gripper 105a and the tip nip portion 105bx of the fixed gripper 105b are always in pressure contact with each other by the urging spring 107 (FIG. 16A).

  The fixed gripper 105b is fitted and supported in a guide groove 115 (FIG. 16) formed in the carrier member 110 so as to be movable in the carry-out direction. Further, the movable gripper 105a (FIG. 16) is connected to a traveling belt 116 built in the carrier member 110 by a connection spring 117. Accordingly, when the traveling belt 116 of the carrier member 110 rotates in the left direction in FIG. 16, the fixed gripper 105b and the movable gripper 105a move in the sheet bundle carrying-out direction with the leading end nip portions 105ax and 105bx being in pressure contact with each other ( FIG. 16 (a) state). When the traveling belt 116 rotates backward in the right direction in FIG. 16, the movable gripper 105a swings clockwise around the pivot pin 106, and the tip nip portion 105ax is gripped away from the tip nip portion 105bx of the fixed gripper 105b. Is released (state shown in FIG. 16B).

"Carrier member 110"
The carrier member 110 that mounts and supports the sheet gripping mechanism 105 will be described. As shown in FIGS. 12 and 16, the carrier member 110 is an appropriately shaped frame member that supports the sheet gripping mechanism 105, and the sheet bundle unloading direction along the guide groove 29 </ b> G (FIG. 13) formed in the processing tray 29. Is supported so as to be movable.

  A support structure of the carrier member 110 will be described. The rear end portion 110b of the carrier member 110 is supported by the slide member 119 so as to linearly reciprocate along the slide member 119 shown in FIG. Further, the leading end portion 110a (FIG. 16) of the carrier member 110 reciprocates while drawing a loop along the loop guide groove 29Ga shown in FIG. As a result, the sheet gripping mechanism 105 mounted on the carrier member 110 moves from the standby position to the carry-out position by the upper path protruding on the processing tray, and after the sheet bundle is carried out to the stack tray 21, It returns to the standby position with the lower pass. Reference numeral 111 shown in FIG. 16 is a guide pin provided at the front end portion 110a of the carrier member 110, and is fitted in the loop guide groove 29Ga.

“Sliding member 119”
As shown in FIG. 13, the slide member 119 is fitted to the guide rail 121 arranged at the bottom of the processing tray 29 so that a predetermined stroke can be reciprocated in the same direction as the guide groove 29G (upper and lower ends in FIG. 13). It is supported. A driving rotary shaft 125 is mounted on the slide member 119. A rear end portion 110 b of the carrier member 110 is axially connected to the drive rotation shaft 125. FIG. 13 shows the state of the shaft connection, and the carrier member 110 is connected so as to reciprocate with a predetermined stroke in the sheet bundle unloading direction by the drive rotation shaft 125 of the rear end portion 110b, and at the same time, the front end portion 110a is driven by this drive. The rotary shaft 125 is swingable. The slide member 119 is connected to a drive arm (crank member) 126 (FIG. 16), and is reciprocated by a predetermined stroke by the drive arm 126. Further, the driving pulley of the traveling belt 116 is connected to the driving rotating shaft 125 (FIGS. 13 and 16), and the gripping mechanism driving unit 127 (FIG. 16) is connected.

"Loop guide groove 29Ga"
Loop guide grooves 29Ga (FIGS. 13 and 14) facing each other are formed on the left and right side walls of the guide groove 29G. In the loop guide groove 29Ga, a guide pin 111 (FIGS. 13, 15, and 16) provided at the tip 110a (FIGS. 13 and 16) of the carrier member 110 is fitted and supported. The loop guide groove 29Ga (FIG. 14) is an endless groove formed in a loop shape by the upper travel path 113a and the lower travel path 113b along the sheet support surface 29a of the processing tray 29. The guide pin 111 moves from the standby position to the unloading position along the upper travel path 113a (outward path), and moves from the unloading position to the standby position along the lower travel path 113b (return path).

  Since the carrier member 110 supported by the slide member 119 and the loop guide groove 29Ga moves from the standby position to the stack tray 21 side as shown in FIG. 14, the guide pins 111 are guided to the upper travel path 113a. Move while maintaining a horizontal posture. Further, when the carrier member 110 returns from the stack tray 21 to the standby position, the guide pin 111 is guided to the lower travel path 113b, and thus moves in an inclined posture.

  Further, as shown in FIG. 14, the loop guide groove 29Ga is formed with a loop groove 112 for guiding the guide pin 108 (FIGS. 12 and 16) provided on the movable gripper 105a of the sheet gripping mechanism 105. The movable gripper 105a and the fixed gripper 105b move along the loop groove 112.

  The sheet gripping mechanism 105 mounted on the carrier member 110 has an operating posture protruding above the processing tray 29 when the guide pin 111 of the carrier member 110 is guided by the upper travel path 113a and moves in the sheet bundle carrying-out direction. . When the guide pin 111 is guided by the lower travel path 113b and moves to the standby position, the sheet gripping mechanism 105 assumes a standby posture that is immersed in the guide groove. This state will be described later with reference to FIGS.

  As shown in FIG. 16, the carrier member 110 configured in this manner is provided with a pair of pulleys 130a and 130b before and after the sheet bundle carrying-out direction, and a traveling belt 116 (see also FIG. 13) is placed between the pulleys. Passed. One drive pulley 130 b is supported by the drive rotation shaft 125. The rotation of the drive rotation shaft 125 causes the sheet gripping mechanism 105 to move to the proximal end storage position (the state shown in FIG. 18A) that overlaps the carrier member 110, and the leading end unloading position that protrudes from the carrier member 110 in the sheet bundle unloading direction (see FIG. 20 (a) state).

“Mounting structure of sheet gripping mechanism 105”
The carrier member 110 is disposed at the bottom of the processing tray 29, and the sheet gripping mechanism 105 is mounted on the top thereof. As described above, the sheet gripping mechanism 105 is configured by connecting the movable gripper 105a to the upper portion of the fixed gripper 105b by the pivot pin 106 (FIGS. 16 and 17). The fixed gripper 105b is supported by the carrier member 110 so as to be movable in the sheet bundle carrying-out direction. Reference numeral 115 shown in FIG. 16 is a slide guide groove formed in the carrier member 110. A fixed gripper 105 b is fitted and supported in the guide groove 115. The movable gripper 105a is pivotally supported by the fixed gripper 105b by a pivot pin 106, but its rear end is connected to a traveling belt 116 built in the carrier member 110 by a connection spring 117. As shown in FIGS. 15 and 16, the carrier member 110 and the sheet gripping mechanism 105 include a carrier driving unit 114 and a gripping mechanism driving unit 127, respectively.

"Carrier driver 114"
As shown in FIG. 13, the carrier member 110 is connected (coupled) to the slide member 119 with a drive rotating shaft 125. As schematically shown in FIG. 16, a shaft pin 122 is integrally formed with the slide member 119, and a drive arm 126 is fitted to the shaft pin 122. The drive arm 126 is a crank member, and is connected to the drive motor MH so as to swing around a swing shaft 131 supported by the apparatus frame. The drive arm 126 and the shaft pin 122 are connected by a long hole 122a. Therefore, when the drive arm 126 is moved back and forth by a predetermined angle (oscillated left and right in FIG. 16) by the drive motor MH, the slide member 119 reciprocates back and forth with a predetermined stroke. As the drive arm 126 moves back and forth, the rear end portion 110b of the carrier member 110 moves back and forth along a linear trajectory, and the front end portion 110a moves back and forth along a loop trajectory along the loop guide groove 29Ga. As described above, the carrier member 110 includes the carrier driving unit 114 that moves the carrier member 110 in the sheet bundle carrying-out direction along the processing tray 29.

“Grip mechanism drive unit 127”
In the schematic view of FIG. 16, the fixed gripper 105 b and the movable gripper 105 a constituting the sheet gripping mechanism 105 are connected to each other by a pivot pin 106. The fixed gripper 105b is supported by the carrier member 110 so as to move back and forth in the sheet bundle carrying-out direction along the slide guide groove 115. Further, the rear end portion of the movable gripper 105 a is connected to the traveling belt 116 of the carrier member 110 by a connection spring 117. A driving motor ME is connected to the driving pulley 130b of the traveling belt 116 provided on the carrier member 110. The drive motor ME is a motor capable of forward and reverse rotation. When the drive motor ME rotates in the forward direction, the traveling belt 116 rotates (circulates) in the left direction in FIG. The movable gripper 105a and the fixed gripper 105b are moved along the slide guide groove 115 from the standby position to the carry-out position (sheet bundle carrying-out direction) following the rotation of the traveling belt 116.

  When the drive motor ME is rotated in the reverse direction, as shown in FIG. 16B, the movable gripper 105a and the fixed gripper 105b move from the carry-out position to the standby position (return direction). At the same time, when the traveling belt 116 further rotates rearward from the standby position, the connecting spring 117 moves in the clockwise direction following the drive pulley 130b. With the backward movement of the drive pulley 130b, the connecting spring 117 pulls the rear end portion of the movable gripper 105a downward. At this time, the movable gripper 105a rotates clockwise around the pivot pin 106, and the nip portion 105ax at the tip is expanded upward (see FIG. 16B). As described above, the sheet gripping mechanism 105 includes the gripping mechanism driving unit 127 that moves the position of the sheet gripping mechanism 105 in the sheet bundle carrying-out direction along the carrier member 110.

“Operation of the sheet gripping mechanism 105”
The operation of the sheet gripping mechanism 105 will be described. The sheet gripping mechanism 105 includes the “first standby position Gp1”, “second standby position Gp2”, “nip position Gp3”, “bundle unloading position Gp4”, “nip release position Gp5”, and “first standby position Gp1”. It is controlled to move in order. The control unit 167 of the sheet gripping mechanism 105 will be described later.

“First standby position Gp1”
A control unit 167 (FIG. 25), which will be described later, moves the sheet gripping mechanism 105 to the first standby position Gp1 shown in FIG. 18A in an “initial operation” (described later) when the sheet processing apparatus B is activated. At the first standby position Gp1, the sheet gripping mechanism 105 assumes a standby posture that is immersed in the guide groove 29G (FIG. 13) of the processing tray 29. When the sheet gripping mechanism 105 is in this standby position, the sheet carried on the processing tray 29 is abutted and aligned with the sheet end regulating portion 32 (FIG. 3) as shown in FIG. Accordingly, the sheet gripping mechanism 105 is stacked on the processing tray 29 with the sheet gripping mechanism 105 in the standby posture, and post-processing is performed at a preset processing position of the sheet bundle.

“Backward movement of the sheet gripping mechanism 105”
In response to the job end signal from the image forming apparatus A, the controller 167 (FIG. 25) moves the sheet gripping mechanism 105 backward toward the second standby position Gp2 on the rear side. The control unit 167 rotates the drive motor MH of the drive arm 126 backward by a predetermined amount. In the process of retreating toward the second standby position Gp2, in the sheet gripping mechanism 105, the guide pin 111 of the carrier member 110 moves from the lower travel path 113b of the loop guide groove 29Ga (FIG. 14) to the upper travel path 131a. The movable gripper 105a protrudes above the sheet support surface 29a of the processing tray 29 (FIG. 18C). At this time, the rear end Pb of the sheet S is pushed upward by the movable gripper 105a, but the sheet end regulating portion 32 follows the rear end Pb of the sheet from the position of the broken line to the position of the solid line as shown in FIG. Then, it is elastically deformed upward and curved. This ensures a smooth movement of the sheet gripping mechanism 105.

“Second standby position Gp2”
Next, the control unit 167 rotates the drive motor MH of the drive arm 126 (FIGS. 16 and 17) reversely by a predetermined amount and then stops it. And the control part 167 rotates the drive motor ME of the drive pulley 130b provided in the carrier member 110 clockwise (FIG. 16 (a) (b)). Then, the movable gripper 105a shifts from the nip posture of FIG. 18C to the nip release posture of FIG. In this state, the sheet gripping mechanism 105 is positioned at the second standby position Gp2.

"Nip operation"
The control unit 167 rotates the drive motor MH of the drive arm 126 (FIGS. 16 and 17) in the forward direction, and moves the carrier member 110 in the sheet bundle carrying-out direction. Simultaneously with this drive control, the control unit 167 rotates the drive pulley 130b of the carrier member 110 in the clockwise direction (FIGS. 16A and 16B). At this time, the sheet gripping mechanism 105 can be stopped by adjusting the moving speed Vb of the traveling belt 116 with respect to the moving speed Vc of the carrier member 110. That is, when the sheet gripping mechanism 105 is moved in the direction opposite to the moving direction of the carrier member 110 with respect to the sheet on the processing tray 29, the sheet gripping mechanism 105 is stationary when viewed from the sheet. For example, when the speeds Vc and Vb are set to the same speed (Vc = −Vb), the sheet gripping mechanism 105 is stationary. Thus, the grip operation by the sheet gripping mechanism 105 can be performed reliably.

  Next, the control unit 167 continuously rotates the drive motor MH of the drive arm 126 in the forward direction, and simultaneously rotates the drive pulley 130b of the carrier member 110 in the counterclockwise direction (FIGS. 16A and 16B). Then, as described in FIGS. 16A and 16B, the connection spring 117 is loosened by the movement of the traveling belt 116, and the movable gripper 105 a is pressed against the fixed gripper 105 b by the biasing spring 107. Thus, the rear end portion of the sheet bundle on the processing tray 69 is nipped (gripped) by the movable gripper 105a and the fixed gripper 105b. This state is shown in FIG.

`` Move bundle transfer position ''
The control unit 167 stops the drive pulley 130b (FIGS. 16A and 16B) of the carrier member 110 and continues the forward rotation of the drive motor MH of the drive arm 126. Then, the sheet bundle PT nipped by the sheet gripping mechanism 105 is transferred along the processing tray 29 from the state shown in FIG. 19B to the state shown in FIG. In a state where the sheet bundle is transferred to the carry-out position shown in FIG. 19C, the control unit 167 rotates the drive pulley 130b of the carrier member 110 counterclockwise. Then, the fixed / movable grippers 105a and 105b connected to the running belt 116 protrude from the carrier member 110 to the upper side of the stack tray 21 (FIGS. 1 and 2) in the state of FIG. As a result, the rear end of the sheet bundle is carried out onto the stack tray 21 and the front end thereof protrudes above the uppermost sheet bundle on the tray.

"Nip released"
Next, the control unit 167 temporarily stops the drive motor MH of the drive arm 126. Then, the carrier member 110 falls in the loop guide groove 29Ga. Then, the sheet gripping mechanism 105 drops onto the uppermost sheet on the tray in the state shown in FIG. Therefore, the control unit 167 reversely rotates the drive motor MH of the drive arm 126 (FIGS. 16A and 16B). Then, the carrier member 110 returns to the first standby position Gp1 side along the lower travel path 113b of the loop guide groove 29Ga. At this time, the sheet bundle nipped by the sheet gripping mechanism 105 is blocked by the side wall of the stack tray 21 and the nip is released (FIG. 20C).

"Return state"
Next, the control unit 167 continues the rotation of the drive motor MH of the drive arm 126 to return the carrier member 110 from the bundle carry-out position Gp4 to the first standby position Gp1. Then, the sheet gripping mechanism 105 returns to the state of being immersed in the guide groove 29G of the processing tray 29 in the state of FIG.

[Safety mechanism for tray output]
In the processing tray 29, the following safety mechanism 135 is disposed at the tray discharge port 29 x at the exit end for carrying out the sheet bundle to the stack tray 21. The safety mechanism 135 includes a foreign matter detection unit 137 disposed at the tray discharge port 29x, a control unit that prevents the stapler unit 31 from operating based on detection information from the foreign matter detection unit 137, and the like. The foreign matter detection unit 137 includes a shielding member 133 that opens and closes the tray discharge port 29x and a position detection sensor St that detects the position of the shielding member 133.

“Shielding member 133 of foreign object detector 137”
The shielding member 133 is disposed at the tray discharge port 29x of the processing tray 29, and opens and closes the tray discharge port 29x formed above the sheet support surface 29a of the processing tray 29. The shielding member 133 is a shutter plate that abuts on the uppermost sheet on the sheet support surface 29a of the processing tray 29, and always abuts on the uppermost sheet with its own weight so as to shield the tray discharge port 29x. It has become. The reason why the shielding member 133 is provided at the tray discharge port 29x is to prevent foreign matters such as office tools from entering the post-processing section or the user from inadvertently entering the finger on the processing tray 29. is there.

  The shielding member 133 is attached to the outer casing 20 so as to be movable up and down so as not to hinder the sheet stacking on the processing tray 29 or the sheet bundle carrying out of the processed sheet bundle to the stack tray 21. The shielding member 133 opens the tray discharge port 29x when the user moves upward when the sheets accumulated on the processing tray 29 are jammed or when the stapler unit 31 is jammed. Jam processing, needle clogging processing, etc. can be performed.

“Position Detection Sensor St of Foreign Object Detection Unit 137”
The position detection sensor St detects the open / close state of the shielding member 133. A sensor flag 134 is provided on the shielding member 133. In the casing 20, a sensor 138 (a micro switch in the drawing) having a sensor actuator Se that detects the sensor flag 134 is disposed. The detection signal of the sensor 138 is transferred to the control unit 168 so that the stapler unit 31 does not operate.

  The height of the shielding member 133 varies depending on the number of sheets stacked on the processing tray 29. The height is low when the number of stacked sheets is small, and high when the number of stacked sheets is large. Go up and down. If the sensor 138 detects the fixed height position of the shielding member 133 so as to allow or not operate the stapler unit 31, the following problem arises. That is, if the stacking height of the sheets stacked on the processing tray 29 is set high, the height position of the shielding member 133 detected by the sensor 138 must be set high accordingly. If the stacking height of the sheets stacked on the processing tray 29 is set to a low position, the stapler unit 31 does not operate during normal operation. For this reason, when an erroneous operation of lifting the shielding member 133 is performed in a state where several sheets are stacked on the processing tray 29, there is a problem that the stapler unit 31 operates without the sensor 138 detecting the shielding member 133. .

  In order to solve this problem, the safety mechanism 135 employs one of the following two methods. (I) The height of the detection position of the sensor 138 is adjusted according to the thickness of the stacked sheet bundle. (Ii) The sensor 138 detects a plurality of height positions, and determines whether or not to operate the stapler unit 31 according to the bundle thickness of the stacked sheets.

  (I) An embodiment in which the height of the detection position of the sensor 138 is adjusted according to the thickness of the stacked sheet bundle. As shown in FIG. 21, the micro switch constituting the sensor 138 is supported on the casing 20 by a guide rail (not shown) or the like that can move up and down along the sheet stacking direction. A rack gear 141 is provided on the sensor bracket 140 on which the microswitch is mounted, and a pinion 142 connected to the stepping motor MT is engaged with the rack gear 141. In this configuration, when the stepping motor MT is rotated, the sensor 138 moves up and down in the sheet stacking height direction, and the detection height of the sensor flag 134 protruding from the shielding member 133 by the actuator Se of the sensor 138 is detected. The position can be adjusted.

  (Ii) An embodiment in which the sensor 138 detects a plurality of height positions. As shown in FIG. 22, the shielding member 133 is provided with a first flag 134a, a second flag 134b, and a third flag 134c in order from the highest. The control unit 168 determines whether or not to operate the stapler unit 31 based on a signal from the sensor 138 that detects the plurality of flags 134a to 134c.

“Control Unit 168”
The control unit 168 (FIG. 25) is incorporated in the control CPU 160. The control unit 168 in the configuration (i) of the safety mechanism 135 acquires the number of sheets stacked on the processing tray 29 from the image forming apparatus A, for example, from an image data. Then, the control unit 168 causes the arithmetic circuit (not shown) to calculate the sheet bundle thickness accumulated on the processing tray 29 from the preset standard sheet thickness and the number of sheets. The control unit 168 sets the height position of the sensor (microswitch) 138 according to the sheet bundle thickness. A power pulse corresponding to the set height position is supplied to the stepping motor MT. Then, the height position of the sensor 138 changes. The actuator Se of the sensor 138 detects the flag 134 of the shielding member 133 at a height position corresponding to the thickness of the sheet bundle that is partly stacked on the processing tray 29.

  As a result, the sensor 138 detects the flag 134 when the shielding member 133 is raised beyond the thickness of the sheet bundle stacked on the processing tray 29. In this case, the height position of the sensor 138 is set to be slightly higher than the thickness of the sheet bundle to be stacked and aligned. Then, the control unit 168 prevents the stapler unit 31 from operating when the sensor 138 detects the flag 134 of the shielding member 133.

  The control unit 168 in the configuration (ii) of the safety mechanism 135, when the sensor 138 detects the first flag 134a, the bundle thickness of the sheet bundle stacked on the processing tray 29 and the preset flags 134a to 134a. The height position of 134c is compared. Then, the control unit 168 determines “abnormal” when the height position of the flag is high, and prevents the stapler unit 31 from operating. For this reason, the control unit 168 includes a count counter that detects the number of sheets carried out to the processing tray 29, and an arithmetic circuit (not shown) that calculates the sheet bundle thickness from the count number. When the sensor 138 detects the first flag 134a, the control unit 168 compares the preset height position of the first flag 134a with the bundle thickness of the sheet bundle stacked on the processing tray 29. Then, it is determined whether or not the stapler unit 31 is operated. Next, when the sensor 138 detects the second flag 134b, the height position of the second flag set in advance and the bundle thickness of the sheet bundle stacked on the processing tray are compared to determine whether or not there is an abnormality. Determine. Similarly, it is determined whether or not the third flag 134c is abnormal.

  In the “abnormality determination”, the thickness of the sheet bundle stacked on the processing tray is compared with a preset flag detection position (height position), and the shielding member 133 is positioned at the top of the processing tray 29. The state of being lifted above the seat. The detection results of the first, second, and third flags 134a, 134b, and 134c are stored in a storage circuit (not shown), and the signal from the sensor 138 is the first flag signal, or the second and third flags. It is designed to identify whether the signal is a signal.

  In this way, when the sensor 138 issues the first detection signal from the initial state, the control unit 168 controls the bundle thickness of the sheet bundle stacked on the processing tray and the height position of the first flag 134a. To compare. The control unit 168 compares the bundle thickness of the sheet bundle with the height position of the second flag 134b for the second detection signal. The control unit 168 similarly determines the third detection signal. Accordingly, the control unit 168 can determine “abnormal” by detecting the open / closed state of the shielding member 133 step by step according to the thickness of the sheet bundle stacked on the processing tray 29.

[Storage section]
On the side wall of the casing 20, a stack tray 21 and a saddle tray 22 are arranged vertically as shown in FIG. The stack tray 21 stands by at the exit end (tray discharge port) 29x of the processing tray 29 so as to store the sheet bundle that has been subjected to the binding processing from the first processing unit BX1, and moves up and down along the casing 20. It has become. The saddle tray 22 is disposed downstream of the stacking guide 45, the folding processing mechanism 44, and the trimmer unit 90 in the second processing unit BX2. The trimmer unit 90 cuts and aligns a predetermined amount of the small edge portion of the folded sheet folded by the folding processing mechanism 44. The saddle tray 22 is disposed so as to store a sheet bundle that is processed in a booklet form from the second processing unit BX2 and discharged from the paper discharge port 22x.

[Raising / lowering mechanism of stack tray 21]
The stack tray 21 will be described with reference to FIG. The stack tray 21 is raised and lowered according to the stacking height of sheets. The stack tray 21 is formed in a tray shape for stacking sheets, and protrudes from the side wall of the casing 20 to the outside of the apparatus. As shown in FIG. 23, the tray base end portion 21a is provided with guide rollers 20r at two upper and lower portions. The guide roller 20r is fitted and supported by an elevating guide 20u provided in the casing 20.

  A lift motor MS is mounted on the bottom of the stack tray 21. The lift motor MS is connected to a drive pinion 21p via a speed reduction mechanism. A rack gear 20h is disposed in the casing 20 in the sheet stacking direction (vertical direction in FIG. 23), and a drive pinion 21p is engaged with the rack gear 20h. The elevating motor MS is a motor capable of forward and reverse rotation. The drive shaft of the lift motor MS is provided with an encoder (not shown) that detects the amount of rotation. The casing 20 is provided with a level sensor Sr that detects the height position of the uppermost stacked sheet.

[Level sensor Sr]
As shown in FIG. 23, the level sensor Sr includes an arm lever 58, a sensor S21 for detecting the position of the arm lever 58, and an operating solenoid SL2 connected to the arm lever 58. The lifting control unit 164 (FIG. 25) operates the operating solenoid SL2 in response to the paper discharge instruction signal to move the arm lever 58 up and down. The sheet discharge instruction signal is issued from the lift control unit 164 at a timing after the expected time for the sheet to reach the stack tray 21 from the sheet rear end passage signal of the sheet discharge sensor S2 (FIG. 22). Further, the elevation control unit 164 (FIG. 25) raises and lowers the stack tray 21 at a timing after the expected time that the trailing end of the sheet bundle reaches the stack tray 21 from the operation signal of the sheet gripping mechanism 105. ing.

  Therefore, the stack tray 21 moves up and down in the sheet stacking direction (up and down direction in FIG. 23) when the lifting motor MS rotates forward and backward. The level sensor Sr detects the height position of the stack tray 21 and the position of the uppermost sheet of the sheet bundle when the sheet bundle is stacked on the stack tray 21. Based on the detection result, the lifting motor MS is rotationally driven in the forward and reverse directions under the control of the lifting control unit 164. The amount of rotation of the lifting motor MS is detected by an encoder. When the sheet stacking surface 21b of the stack tray 21 is stacked on the stack tray 21, when the uppermost sheet of the sheet stack reaches a position slightly lower than the tray discharge port 29x, the stack tray 21 moves up and down. Stop.

[Elevation control unit 164]
The lift control unit 164 (FIG. 25) that controls the lift motor MS is configured as follows. A control mode for transferring a sheet from the paper discharge port 25x onto the stack tray 21 will be described. The sheet is unloaded in the “straight sheet discharge mode”, “bridge unloading mode”, and “process bundle unloading mode” from the sheet discharge outlet 25x. This carry-out mode is selected, for example, when the processing mode of the image forming apparatus A is set.

  The “straight paper discharge mode” is a mode in which an image-formed sheet is directly carried out from the paper discharge port 25x to the stack tray 21 without being processed. In the straight paper discharge mode, the sheet sent to the sheet carry-in port 23a (FIGS. 1 and 2) is sent to the first transport path K1 (FIG. 21), and passes through the paper discharge roller pair 25 and the paper discharge sensor S2. Then, it is conveyed onto the processing tray 29. At this time, the movable roller 26a of the switchback roller pair 26 is in pressure contact with the driven roller 26b disposed on the processing tray 29 and rotates in the paper discharge direction (clockwise in FIGS. 21 and 24A). . The switchback roller pair 26 carries out the sheet from the sheet discharge outlet 25 x onto the processing tray 29 and accumulates it on the uppermost sheet on the stack tray 21. The driven roller 26b is rotated by a motor in a direction in which the movable roller 26a conveys the sheet when a plurality of sheets are sandwiched between the movable roller 26a. However, the driven roller 26b has a clutch (not shown) so as to rotate following the movable roller 26a regardless of the rotational force of the motor when there is one sheet.

  The “bridge carry-out mode” is a mode in which sheets are stacked in a bundle on the processing tray 29 from the paper discharge port 25x in order to perform post-processing on the sheets on which images have been formed. In this bridge carry-out mode, the sheet sent to the sheet carry-in port 23a (FIGS. 1 and 2) is sent to the first transport path K1 (FIG. 21), and passes through the paper discharge roller pair 25 and the paper discharge sensor S2. It is conveyed to the processing tray 29. Around the processing tray 29, a sheet end regulating portion 32, a switchback roller pair 26, an aligning portion 51, and a side aligning portion 34 are arranged. The sheets from the sheet discharge outlet 25x are collected in a bundle on the uppermost sheet on the processing tray 29.

  The “processing bundle carry-out mode” is a mode in which the rear end of the sheet bundle stacked on the processing tray 29 (FIG. 3) is bound by the stapler unit 31, and the sheet bundle is carried out from the processing tray 29 to the stack tray 21. is there. In the processing tray 29, a sheet bundle carrying-out unit 100 is arranged.

  In each of the above modes, the elevation controller 164 (FIG. 25) determines the height difference H between the uppermost sheet stacked on the stack tray 21 and the sheet support surface 29a of the processing tray 29 as the “straight discharge mode”. In this case, the first height position H1 (FIG. 24A) is set. In the “bridge carry-out mode”, the second height position H2 (FIG. 24B) is set. In the “process bundle carry-out mode”, the third height position H3 (FIG. 24C) is set. Set. The height difference H at this time is set so as to increase in the order of the first, second, and third height positions (H1 <H2 <H3). In the control of the height position, the level sensor Sr detects the position of the uppermost sheet on the stack tray 21, and the elevation motor MS rotates a predetermined amount based on the detection signal to set the height difference H.

  The first height position H1 is set so that there is almost no height difference between the uppermost sheet on the stack tray 21 and the sheet support surface 29a. That is, the first height position H1 is set so that the sheet sent to the sheet support surface 29a is smoothly carried onto the uppermost sheet on the stack tray 21. However, the rear end of the uppermost sheet may curl up, or the uppermost sheet may be positioned above the sheet support surface 29a due to an elevation error of the stack tray 21. Therefore, the height of the stack tray 21 is set so that the uppermost sheet on the stack tray 21 is slightly lower than the sheet support surface 29a.

  At the same time as this consideration, it is difficult to control the stack tray 21 to be lowered by the thickness of one sheet each time a sheet is stacked. Therefore, normally, the stack tray 21 is lowered (can be lowered) when the level sensor Sr detects that the sheet discharge from the sheet discharge outlet 25x has been repeated several times. For this reason, the first height position H1 is set to 5 mm to 10 mm, for example.

  In the second height position H2, when stacking a sheet bundle on the stack tray 21, at least a difference in height between the uppermost sheet on the stack tray 21 and the sheet support surface 29a is stacked on the stack tray 21. The thickness corresponding to the thickness of the sheet bundle is set slightly larger than this. If setting is made so that there is no difference in height between the two, there is a problem that the sheet carried out from the sheet discharge outlet 25x pushes the sheet stacked on the stack tray and shifts the position of the sheet. Further, the stack tray 21 is inclined so that the front end in the paper discharge direction becomes higher (FIG. 24B). For this reason, the sheet bundle stacked on the processing tray 29 is bent in a state in which the leading end in the sheet discharge direction is pushed upward. The trailing edges (binding ends) of the sheets that are aligned in a bundle due to the curvature become uneven. As a result, when the rear end portion of the sheet bundle on the processing tray 29 is bound, there is a problem that the rear end portion is in an irregular state.

  Therefore, the second height position H2 is set to a height difference larger than the first height position H1. The height position H2 corresponding to the allowable positional deviation amount of the rear end portion due to the curvature when the sheet bundle having the maximum allowable stacking height is stacked on the sheet support surface 29a of the processing tray was experimentally determined. As a result, it is found that the second height position H2 is preferably about 10 mm to 30 mm, and is set within the range.

  The third height position H3 is a sheet in which the height difference between the uppermost sheet on the stack tray 21 and the sheet support surface 29a is the maximum allowable stacking height of the sheets stacked on the processing tray 29 set in advance. It is set sufficiently larger than the thickness equivalent of the bundle. That is, when the sheet bundle with the rear end of the processing tray 29 bound is carried out onto the stack tray 21, the height difference (height position H3) between the uppermost sheet and the sheet support surface 29a is at least. The maximum allowable loading height is set. In this case, the sheet bundle on the processing tray 29 is carried out by being gripped (gripped) by the sheet gripping mechanism 105. This is because when the unbound sheet bundle is dropped and stored from the sheet support surface 29a of the processing tray 29, the alignment state is disturbed. Therefore, the sheet gripping mechanism 105 grips the rear end portion of the sheet bundle and releases the grip immediately before the rear end portion of the sheet bundle is landed on the uppermost sheet on the stack tray 21. Yes. As a result, the sheet bundle can be stacked on the stack tray while maintaining alignment of the trailing end of the sheet bundle. Incidentally, the third height position H3 is set to 30 mm to 50 mm.

  The elevation controller 164 performs the following control when the stack tray 21 is lowered from the second height position H2 to the third height position H3 in the “processing bundle carry-out mode”. (I) The lift motor MS is activated by an operation completion signal of the stapler unit 31 or a timing signal at which the carrier member 110 starts moving in the sheet carry-out direction by this signal, and the stack tray 21 is moved from the second height position H2 to the third position. Lower to height position H3. (Ii) The stacking-processed sheet bundle reaches the stack tray 21 from the operation completion signal of the stapler unit 31, and the lifting motor MS is activated immediately before the trailing edge of the sheet falls on the uppermost sheet. The tray is lowered from the second height position H2 to the third height position H3.

  Then, the lift control unit 164 drops the grip of the sheet gripping mechanism 105, the height difference (third height position H 3) between the sheet support surface 29 a of the processing tray 29 and the stack tray 21, and the trailing end of the sheet bundle drops. Control to release in the process of. Therefore, the sheet bundle is gradually dropped and accumulated on the uppermost sheet with a small drop. As a result, the alignment of the sheets accumulated on the stack tray 21 can be maintained.

[Explanation of control unit]
The control unit of the image forming system C will be described based on the block diagram of FIG. An image forming system C illustrated in FIG. 1 includes an image forming apparatus control unit 150 of the image forming apparatus A, a post-processing control unit 160 of the sheet processing apparatus B, and the like. The image forming apparatus control unit 150 includes an image formation control unit 151, a paper feed control unit 152, and an input unit 153. Then, an “image forming mode” and a “post-processing mode” are selected by the user from the control panel 18 provided in the input unit 153.

  The “image forming mode” is a mode for setting the number of printouts, sheet size, color / monochrome printing, enlargement / reduction printing, duplex / single-sided printing, and other image formation conditions. The image forming apparatus control unit 150 controls the image forming control unit 151 and the paper feed control unit 152 according to the set image forming conditions to form a predetermined image on the sheet, and then removes the sheet from the paper discharge port 3. Carry out sequentially.

  “Post-processing mode” includes modes such as “print-out mode”, “staple binding finishing mode”, and “sheet bundle folding finishing mode”. Therefore, the image forming apparatus control unit 150 transfers to the post-processing control unit 160 the post-processing finishing mode, the number of sheets, the number of copies, and the binding mode (single-position binding or plural-position binding) information. At the same time, the image forming apparatus control unit 150 transfers a job end signal to the post-processing control unit 160 every time image formation ends.

  The post-processing control unit 160 includes a control CPU 161 that operates the sheet processing apparatus B according to a designated finishing mode, a ROM 162 that stores a post-processing operation program, and a RAM 163 that stores control data. The control CPU 161 includes a sheet conveyance control unit 164a that performs conveyance of the sheet sent to the sheet carry-in port 23a, and a punch control unit 164p that operates the punch unit 60 that opens a hole in the sheet sent to the sheet carry-in port 23a. I have. Further, the control CPU 161 includes a sheet stacking operation control unit 164b that executes a stacking operation of sheets, a binding operation control unit 164c that executes a binding process of sheets, and a sheet bundle folding operation control unit 164d that executes a bundle folding operation of sheets. It has.

  The sheet conveyance control unit 164a is connected to a control circuit of a drive motor (not shown) for the carry-in roller 23 and the paper discharge roller pair 25 in the first conveyance path K1 (FIG. 2), and is arranged in the first conveyance path K1. The detection signal from the sheet sensor S1 is received. Further, the sheet stacking operation control unit 164b is connected to a drive circuit of a forward / reverse rotation motor of the switchback roller pair 26 and a shift motor of the sheet end regulating unit 32 in order to stack sheets on the processing tray 29 (FIG. 3). . The binding operation control unit 164c is connected to the drive circuit of the drive motor MD built in the stapler unit 31 for trailing edge binding of the processing tray 29 (FIG. 2) and the saddle stitching stapler unit 40 of the accumulation guide 45.

  The sheet bundle folding operation control unit 164d is connected to a drive circuit for a driving motor that drives and rotates the folding rolls 46a and 46b (FIG. 2) and a driving circuit for a clutch (not shown) of the folding rolls 46a and 46b. Further, the sheet bundle folding operation control unit 164d is connected to a control circuit of a shift unit that controls the raising and lowering of the conveying roller 27 and the leading end stopper 43 of the stacking guide 45 in the second conveying path K2 (FIG. 2). Further, the sheet bundle folding operation control unit 164d activates the pushing plate 47 that folds the sheet bundle into two by pushing the sheet bundle bound to the saddle stitching stapler unit 40 into the nip of the folding rolls 46a and 46b. Has been. Further, it is wired so as to receive a detection signal from a sheet sensor arranged in the second conveyance path K2. The post-processing control unit 160 described above causes the sheet processing apparatus B to execute the next processing operation.

"Printout mode"
In the printout mode, the image forming apparatus A forms a series of images on a sheet, and sequentially conveys the sheet from the sheet discharge port 3 face down, and guides it to the sheet discharge roller pair 25 through the first conveyance path K1. To do. The sheet on which the image is formed by the image forming unit 2 has an image forming surface facing upward (face up), but is passed through the front / back reversing path 71 while being guided from the fixing device 8 to the paper discharge port 3. Both sides are reversed and face down. The sheet conveyance control unit 164a moves the movable roller 26a upward after an expected time that the sheet leading edge reaches the switchback roller pair 26 of the processing tray 29 based on a signal that the sheet sensor S1 detects the leading edge of the sheet at the sheet discharge outlet 25x. Is lowered onto the processing tray 29 from the standby position. Then, the sheet conveyance control unit 164a rotates the movable roller 26a in the clockwise direction in FIG. The sheet that has entered the processing tray 29 is carried out toward the stack tray 21 by the switchback roller pair 26. In this way, subsequent sheets are sequentially carried out and stacked on the stack tray 21.

  Therefore, the printout mode is a mode in which the sheets formed with the image forming apparatus A are discharged to the stack tray 21 through the first conveyance path K1 of the sheet processing apparatus B and stacked in the page order in the face-down state. .

"Staple binding finish mode"
In the staple binding finishing mode, the image forming apparatus A forms a series of images on a sheet, and sequentially conveys the sheet from the sheet discharge port 3 face down, and passes the first conveyance path K1 to the sheet discharge roller pair 25. invite. The sheet conveyance control unit 164a moves the movable roller 26a upward after an expected time that the sheet leading edge reaches the switchback roller pair 26 of the processing tray 29 based on a signal that the sheet sensor S1 detects the leading edge of the sheet at the sheet discharge outlet 25x. It is lowered onto the processing tray 29 from the standby position. Then, the sheet conveyance control unit 164a rotates the movable roller 26a in the clockwise direction in FIG. Then, the sheet conveyance control unit 164a rotates the movable roller 26a counterclockwise in FIG. 2 after the estimated time when the trailing edge of the sheet is carried onto the processing tray 29. As a result, the sheet is switched back and conveyed onto the processing tray 29 from the paper discharge outlet 25x. By repeating this sheet conveyance control, the sheet conveyance control unit 164a accumulates a desired number of sheets in a bundle in a face-down state on the processing tray 29.

  The control CPU 161 operates the side aligning unit 34 each time the sheets are stacked on the processing tray 29 to align the width direction positions of the sheets stacked on the processing tray 29 (width alignment). Next, the control CPU 161 operates the end binding stapler unit 31 in response to a job end signal from the image forming apparatus A, and binds the rear end portion of the sheet bundle stacked on the processing tray 29. After this stapling operation, the control CPU 161 operates and moves the sheet bundle carrying-out unit 100. Then, the staple-bound sheet bundle is carried out to the stack tray 21 and stacked. As a result, a desired number of sheets formed by the image forming apparatus A are bound and stacked on the stack tray 21.

[Buffer unit 201 and buffer discharge unit 202]
When post-processing such as stapling is performed on the sheet bundle accumulated on the processing tray 29, subsequent sheets sent to the sheet carry-in port 23a during this post-processing operation are temporarily stored (buffered) in the buffer path K3. ) When the sheet bundle that has been processed on the processing tray 29 is carried out, the stored subsequent sheets are transferred to the processing tray 29.

  Hereinafter, configurations and operations of the buffer unit 201 and the buffer discharge unit 202 as holding units will be described. FIG. 26 is a diagram illustrating the configuration of the buffer unit 201 and the buffer discharge unit 202, and FIGS. 27 and 28 are diagrams illustrating the operation of the buffer unit 201 and the buffer discharge unit 202. In FIG. 26, the buffer unit 201 includes a first transport path K1, a second transport path K2, a path switching member 173, a first buffer roller pair 171, a second buffer roller pair 172, and the like. The buffer discharge unit 202 includes a pair of discharge rollers 25 and the like.

  The sheet on which the image is formed by the image forming apparatus A is guided from the sheet discharge port 3 to the sheet carry-in port 23a of the sheet processing apparatus B (see FIG. 1), and is conveyed to the first conveyance path K1 by the carry-in roller 23. In the first transport path K1, a first buffer roller pair 171 and a path switching member 173 are provided at a branch point s1 to the buffer path K3. Further, a second buffer roller pair 172 is provided in the buffer path K3.

  In some cases, the preceding sheet bundle is on the processing tray 29. In this case, in FIG. 27A, the succeeding first sheet P1 is moved along the first transport path K1 and the first buffer roller pair 171 until the rear end (right end in FIG. 27) reaches the branch point s1. The paper is conveyed toward the stack tray 21 by the paper roller pair 25. When the trailing edge of the sheet P1 reaches the branch point s1, as shown in FIG. 27B, the rotation of the first buffer roller pair 171 and the discharge roller pair 25 is reversed in the direction in which the sheet P1 is conveyed to the buffer path K3. At the same time, the path switching member 173 rotates from the broken line position to the solid line position. The path switching member 173 guides the sheet P1 to the buffer path K3 while preventing the sheet P1 from moving backward from the branch point s1 to the first transport path K1. The sheet P1 is conveyed to a predetermined position in the buffer path K3 by the rotation of the second buffer roller pair 172. As shown in FIG. 27, the buffer path K3 is curved and extends vertically downward with respect to the first transport path K1. The sheet P1 that has entered the buffer path K3 having such a shape is curled downward as shown in FIG. 29 depending on the shape of the buffer path K3. Therefore, the sheet easily enters the processing tray 29 when it is carried into the processing tray 29 described later.

  Next, as shown in FIG. 27 (c), when the first sheet P1 and the second sheet P2 constituting one sheet bundle are conveyed from the sheet carry-in port 23a, the second buffer roller The pair 172 sends out the sheet P1 to the first transport path K1 again at a predetermined timing. As a result, the sheet P1 and the sheet P2 merge at the branch point s1. At this time, the feeding of each of the sheets P1 and P2 is controlled so that the leading end (left end in FIG. 27) of the sheet P1 overlaps with the leading end of the sheet P2 retracted by a predetermined amount (offset amount x). . Here, there are two sheets waiting, but when storing more sheets, they are stacked with a predetermined offset amount x. The stacked sheets are conveyed again to the buffer path K3. Thereafter, when a new succeeding sheet is conveyed, it is sent out again to the first conveyance path K1 so as to be shifted by a predetermined offset amount x and overlap. Then, the operations shown in FIGS. 27 (b) and 27 (c) are repeated so that the respective sheets are sequentially stacked while maintaining a predetermined offset amount x. In this manner, the subsequent sheets fed while the processing of the preceding sheet bundle stacked on the processing tray 29 is sequentially stacked to become a plurality of sheets (buffer sheets).

  The processing of the preceding sheet bundle in the processing tray 29 is completed. Then, in FIG. 27D, the two sheets P1 and P2 overlapped with the predetermined offset amount x are first maintained while the offset amount x is maintained by the first buffer roller pair 171 and the paper discharge roller pair 25. The transport path K1 is transported toward the stack tray 21.

  Then, as shown in FIG. 28A, the two sheets P1 and P2 as buffer sheets reach the switchback roller pair 26, and are moved by the movable roller 26a and the driven roller 26b which are lowered from the standby position to the operating position. Further, it is conveyed to the stack tray 21 side. At this time, the offset amount x is maintained. Then, as shown in FIG. 28B, when the rear end of the lowermost sheet (here, sheet P1) passes through the paper discharge port 25x, the front end of the sheet is supported by the stack tray 21. The rear end side is held by the switchback roller pair 26. For this reason, the trailing edge of the sheet falls by its own weight while maintaining the posture and falls (enters) the processing tray 29.

  In this way, when the switchback roller pair 26 is arranged below the branch point s2 (FIG. 28B) from the first transport path K1 to the switchback path (path from the stack tray 21 to the processing tray 29). The sheet can easily enter the processing tray. Next, when the sheet is discharged from the first conveyance path K1, as shown in FIG. 28C, the switchback roller pair 26 reversely rotates in the direction in which the sheets P1 and P2 abut against the sheet end regulating portion 32. start. Further, the aligning unit 51 is lowered from the standby position to the operating position, and is driven in a direction in which the sheets P1 and P2 are abutted against the sheet end regulating unit 32 in the same manner as the switchback roller pair 26. For this reason, the sheets P1 and P2 are conveyed by the switchback roller pair 26, and at the same time, are guided by the aligning unit 51 from the lowermost sheet (here, the sheet P1) to the sheet end regulating unit 32 in order.

  Thus, the offset state of the sheet offset in the first transport path K1 and the buffer path K3 is maintained until it reaches the processing tray 29. For this reason, the aligning part 51 can contact the sheet end regulation part 32 in order from the sheet located at the lowest position. Even in the case of three or more sheets, it can be reliably aligned in the same manner.

  Note that switching the sheet back in the path from the first transport path K1 to the processing tray 29 has the following advantages. That is, FIG. 30 is an explanatory view showing a mode of switching back the seat. Here, an example is shown in which three sheets P1, P2, and P3 are conveyed. First, as shown in FIG. 30A, sheets P1, P2, and P3 stacked with a predetermined offset amount x are moved from the first transport path K1 by the discharge roller pair 25 and the switchback roller pair 26. It is conveyed to the stack tray 21 side. At that time, since the uppermost sheet P3 and the lowermost sheet P1 are in direct contact with the discharge roller pair 25 and the switchback roller pair 26, friction is caused as shown in FIGS. 30 (b) and 30 (c). There is a risk that the offset collapses. However, as shown in FIG. 30 (d), when the switchback is performed, the rotation of the switchback roller pair 26 reverses, so that a deviation in the first conveyance path K1 and a forward / reverse deviation occur, and the collapsed offset is based on There is a return effect. For this reason, the sheet is discharged on the processing tray 29 with the offset maintained, and the aligning unit 51 can correctly align.

  In the present embodiment, an example in which a sheet is switched back and discharged to the processing tray 29 is shown. However, the present invention is not limited to this, and for example, even if the sheet is discharged to the processing tray without being switched back. good. Even in this case, it is necessary to contact the aligning unit 51 in order from the lowest sheet on the processing tray 29. Therefore, contrary to the present embodiment, the leading edge of the succeeding sheet is overlapped with the leading edge of the preceding sheet previously transported to the buffer path in a state where the leading edge of the succeeding sheet is retracted by the predetermined offset amount x.

  The sheet processing apparatus B of the present invention stores a predetermined number of sheets offset in the transport direction by the buffer unit 201, and further, the buffer discharge unit 202 holds the offset state of the predetermined number of sheets on the processing tray 29. To be discharged. For this reason, the friction rotating body 52 can sequentially scrape the offset sheets toward the sheet end regulating portion 32 side. Therefore, a predetermined number of sheets conveyed from the buffer unit 201 can be reliably aligned. Accordingly, it is possible to improve the processing efficiency and reliability of the sheet processing apparatus. The buffer unit 201 and the buffer discharge unit 202 constitute holding means for buffering the conveyed sheet and discharging it to the processing tray 29 as a buffer sheet.

  Further, the buffer discharge unit 202 may switch back the buffer sheet from the first transport path K1 to the second transport path K2, and then discharge the buffer sheet to the processing tray. In this way, it is possible to correct an offset shift that may occur during conveyance of the sheet, and to stably align the sheets. At this time, if a discharge roller for switching back a predetermined number of sheets is disposed below a branch point from the first discharge path to the second discharge path, the predetermined number of sheets offset at the time of switchback is the second. It becomes easier to enter the discharge route. Further, if the offset predetermined number of sheets is curled in the direction from the first discharge path to the second discharge path, the predetermined number of sheets offset at the time of switchback enters the second discharge path. It becomes easy to do. This curling mechanism (curling mechanism) can be realized with a simple configuration if the shape of the storage path of the buffer unit 201 is curved.

"Operation and control of sheet gripping mechanism when buffer processing is performed"
Next, the operation of the sheet bundle unloading unit 100, particularly the sheet gripping mechanism 105, during the buffer processing described above will be described based on the flowchart of FIG. The operation flow of FIG. 34 is executed by the post-processing control unit 160 in the present embodiment, but the present invention is not limited to this, and may be executed by the image forming apparatus control unit 150.

  The sheet gripping mechanism 105 clamps (grips) the sheet bundle PT stacked on the processing tray 29 (S176), moves to the position shown in FIGS. 20B and 31A, and stack tray 21. (S177). If there is a buffer sheet PB that has been subjected to buffer processing (FIG. 31A, YES in S178), the sheet gripping mechanism 105 holds the sheets on the stack tray 21 while FIG. 20B and FIG. Waiting at the position (a) (S179). The sheet gripping mechanism 105 moves until the buffer sheet PB is conveyed toward the stack tray 21 by the paper discharge roller pair 25 (FIG. 31B), and the rear end PBb of the buffer sheet PB comes out of the paper discharge roller pair 25. The sheet on the stack tray 21 is gripped (FIG. 32A). Then, the sheet gripping mechanism 105 releases the grip on the stack tray 21 after the trailing end PBb of the buffer sheet PB exits the pair of paper discharge rollers 25 (FIGS. 20C and 32B). S180). The rear end PBb of the buffer sheet falls on the processing tray 29 as shown in FIG. The sheet gripping mechanism 105 returns to the state shown in FIGS. 20D and 33B (S181). The buffer sheet PB is switched back on the processing tray 29 by the switchback roller pair 26 and the friction rotating body 52 (FIG. 33A), and the rear end is received by the sheet end regulating portion 32 and aligned. (FIG. 33B).

  When the buffer process is not performed (NO in S178), the sheet gripping mechanism 105 moves to the state of FIG. 20B and FIG. 31A, and then waits by gripping the sheet on the spot. If not, the grip is released (S180), and the state returns to the state of FIG. 20 (d) (S181). The above operation is repeated until the last sheet, and the process is terminated (YES in S182).

  By the way, when the buffer sheet is discharged to the processing tray 29, the leading end PBa of the buffer sheet PB passes through the switchback roller pair 26 as shown in FIGS. May extend over the sheet. On the other hand, there are cases where the sheet bundle PT on the stack tray 21 has not been bound while being aligned, or the number of sheet bundles PT is small even when bound. In such a case, since the buffer sheet PB is formed by overlapping several sheets, there is a weight, and there is a possibility that the upper sheet of the sheet bundle on the stack tray 21 or the sheet bundle may be pushed out by its own weight. is there. This phenomenon appears remarkably when the number of buffer sheets is large or heavy.

  However, in the sheet processing apparatus B of the present invention, when the buffer sheet PB passes over the processing tray 29 and extends to the stack tray 21 and is discharged, the sheet gripping mechanism 105 of the sheet bundle PT discharged to the stack tray The gripping is continued. That is, the sheet bundle carrying-out unit 100 holds the sheet bundle PT on the processing tray 29 (holds a plurality of sheets) as shown in FIGS. It can be discharged to a stack tray (receiving means) 21. For this reason, the sheet processing apparatus B can grip the sheet bundle loaded on the processing tray 29 when the sheet bundle carrying-out unit 100 is discharging the buffer sheet from the buffer discharge unit 202, and the sheet bundle is buffered. The following movement is prevented while in contact with the sheet. Therefore, the sheet processing apparatus can prevent the sheets on the stack tray or the sheet bundle from being pushed out by the buffer sheet. In the above, the sheet bundle carrying-out unit 100 constitutes a discharge unit because the sheet stacked on the processing tray 29 is moved while being gripped and discharged from the processing tray 29.

  In the above description, the case where the sheet gripping mechanism 105 of the sheet bundle carrying-out unit 100 waits at the leading end of the stacking tray 29 and receives a buffer sheet has been described, but the present invention is not limited to this.

  In other words, the buffer sheet PB may be discharged while the sheet bundle PT is not discharged to the stack tray 21 and is on the processing tray 29. Even in such a case, the sheet bundle PT on the processing tray 29 may be pushed out by the buffer sheet PB. However, the sheet bundle carrying-out unit 100 holds the sheet bundle stacked on the processing tray 29 until the buffer discharge unit 202 discharges the buffer sheet and ends. Therefore, the sheet processing apparatus B is configured to prevent the sheet bundle from following and moving while in contact with the buffer sheet.

  Note that the sheet bundle carrying-out unit 100 removes the sheet on the processing tray 29 until the buffer sheet is conveyed to the sheet end regulating unit 32 as the regulating unit by the switchback roller pair 26 and the friction rotating body 52 as the conveying unit. It may be gripped. In this case, even if the buffer sheet moves on the sheet on the processing tray 29, the alignment of the sheet on the processing tray 29 is rarely disturbed.

  In the above description, the sheet bundle unloading unit 100 operates to grip the sheet bundle under the control of the control CPU 161 when the paper discharge sensor S2 (FIG. 3) detects the buffer sheet. For this reason, the sheet bundle carrying-out unit 100 starts gripping the sheet after the discharge sensor S2 detects the leading edge of the buffer sheet. When the discharge sensor S2 detects the trailing edge of the buffer sheet, the sheet gripping unit 100 holds the sheet. Is to be canceled. However, the sheet bundle carrying-out unit 100 does not release the gripping when the sheet bundle is gripped and discharged.

  For this reason, the sheet processing apparatus according to the present invention is configured such that when there is a sheet bundle on the processing tray 29, even if the buffer sheet is discharged and the leading end PBa of the buffer sheet PB contacts the sheet bundle on the processing tray, The sheet bundle can be prevented from being pushed out.

  Therefore, in the sheet processing apparatus according to the present invention, when the buffer sheet is discharged to the processing tray, the sheet holding mechanism 105 holds the sheet bundle in front of the buffer sheet, so that the sheet bundle (or sheet) contacts the buffer sheet. Thus, the follow-up movement can be prevented.

  Further, the image forming apparatus A includes a sheet processing apparatus that prevents the sheets stacked on the processing tray and the stack tray from being pushed out by the buffer sheet, and it is necessary to form an image again on the sheet that is pushed and damaged. Therefore, the image forming efficiency can be increased.

A: Image forming apparatus, B: Sheet processing apparatus, C: Image forming system, P: Sheet, PB: Buffer sheet, PT: Sheet bundle, K1: First transport path, K3: Buffer path,
21: Stack tray (receiving means), 23: Loading roller, 25: Paper discharge roller pair, 25x: Paper discharge port, 26: Switchback roller pair (conveying means), 26a: Movable roller, 26b: Driven roller, 29: Processing tray (stacking means), 29a: sheet support surface, 31: edge-binding stapler unit, 32: sheet edge regulating portion (regulating means), 32A: fixed stopper, 32B: right movable stopper, 32C: left movable stopper, 34: Side alignment unit, 44: folding processing mechanism, 52: friction rotating body (conveying means), 100: sheet bundle carrying out part (discharge means), 105: sheet gripping mechanism, 105a: movable gripper, 105b: fixed gripper, 106: pivot Pin 107: Biasing spring 108: Guide pin 110: Carrier member 111: Guide pin 114: Carrier drive unit 127: gripping mechanism driving unit, 160: post-processing control unit of the post-processing device, 161: control CPU, 171: first buffer roller pair, 172: second buffer roller pair, 201: buffer unit (holding means), 202: Buffer discharge unit (holding means).

Claims (6)

A stacking means on which the conveyed sheets are stacked;
Holding means for holding a plurality of conveyed sheets, and conveying the plurality of sheets to the stacking means;
A discharge means for moving the sheet stacked on the stacking means while gripping the sheet and discharging the sheet from the stacking means,
The discharging means is capable of gripping the sheets stacked on the stacking means when the holding means is conveying a plurality of sheets.
A sheet processing apparatus. A receiving means for loading sheets positioned downstream of the stacking means;
The discharging means can move while gripping the sheets stacked on the stacking means, and can discharge the sheets from the stacking means to the receiving means, and the holding means can transport a plurality of sheets. Holding the sheets stacked on the stacking means moved to the receiving means,
The sheet processing apparatus according to claim 1. The receiving means can be raised and lowered with respect to the stacking means, and can be lowered with respect to the stacking means as the stacking height of the stacked sheets increases.
The sheet processing apparatus according to claim 2. The discharging unit grips the sheets stacked on the stacking unit until the plurality of sheets held by the holding unit are conveyed to the stacking unit.
The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is a sheet processing apparatus. Regulation means for regulating the position of the sheet by regulating the sheet conveyed to the stacking means;
Conveying means for conveying the sheet conveyed to the stacking means in the direction of the regulating means,
A plurality of sheets held by the holding means are conveyed to the stacking means, and the discharging means are stacked on the stacking means until the plurality of sheets are conveyed in the direction of the regulating means by the conveying means. Grip the sheet,
The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is a sheet processing apparatus. An image forming unit for forming an image on a sheet;
A sheet processing apparatus for processing a sheet image-formed by the image forming unit,
The sheet processing apparatus is the sheet processing apparatus according to any one of claims 1 to 5.
An image forming apparatus.

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