Sheet processing device and image forming system

Abstract

To achieve productivity improvement of a shift discharge process at a low cost.SOLUTION: In the binding discharge process, by the repetition of transporting a transported sheet in the reverse direction on a processing tray 220 by a raking paddle 240A, batting the rear end of the sheet against a rear end regulating member 290, thereafter moving the sheet by an alignment part 270A in the shift direction and positioning it at the binding position, multiple sheets are positioned at the binding position, and the binding process is performed on them. The multiple bound sheets are discharged onto a loading tray 300 by an upper side discharge roller 230A and a bottom side discharge roller 230B. In the switch back-less shift discharge process, the transported sheet is shifted in the shift direction by the alignment part 270A by driving the drive part without performing the transport in the reverse direction by the raking paddle 240A and is discharged by the upper side discharge roller 230A and the bottom side discharge roller 230B to the loading tray 300.SELECTED DRAWING: Figure 2

Description

Technical Field

[0005] , , , , , , ,

[0006] ,

[0001] The present invention relates to a sheet processing apparatus that performs a predetermined process such as stapling on a sheet. and an image forming system equipped with a sheet processing device

Background Art

[0002] In a sheet processing apparatus, a sheet conveyed in the conveyance direction from a conveyance path is placed on a processing tray, the sheet on the processing tray is conveyed in the direction opposite to the conveyance direction, the rear end of the sheet (the downstream edge in the reverse conveyance direction) is abutted against a rear end regulating member, and a stapling process is performed on the sheet abutted against the rear end regulating member using a stapler. As such a sheet processing apparatus, there is a case where a shift discharge process is performed in which a sheet on which the stapling process is not performed is moved in a shift direction intersecting the conveyance direction and then discharged to a stacking tray (Patent Document 1).

[0003] When performing the shift discharge process with the configuration described in Patent Document 1, the sheet conveyed from the conveyance path is once conveyed in the reverse direction on the processing tray so that the rear end of the sheet abuts against the rear end regulating member, and the sheet abutted against the rear end regulating member is moved in the shift direction by aligning means and then discharged.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] It is desired to realize an improvement in productivity of the above-described shift discharge process at a low cost.

Means for Solving the Problems

[0006] ​One aspect of the present disclosure includes: a first conveying unit for conveying a sheet in a first conveying direction; a placement unit for placing the sheet conveyed by the first conveying unit; abutment unit against which the upstream end of the sheet on the placement unit in the first conveying direction abuts; a second conveying unit for conveying the sheet in a second conveying direction toward the abutment unit, with the upstream end of the sheet on the placement unit in the first conveying direction toward the abutment unit; a shift unit that moves in a shift direction intersecting the first conveying direction while in contact with one edge of the sheet conveyed by the first conveying unit along the first conveying direction, thereby moving the sheet conveyed by the first conveying unit in the shift direction; and a shift unit for moving the shift unit in the shift direction. A drive unit that drives the foot section; a processing unit that performs a binding process on a plurality of sheets that have been transported in the second transport direction by the second transport unit so that their downstream end in the second transport direction abuts against the abutment section, and which have been moved in the shift direction by the shift unit to be positioned at the binding position; a loading section located downstream of the above-described loading section in the first transport direction for loading the sheets transported by the first transport unit; a pair of discharge rollers having an upper discharge roller and a lower discharge roller, configured to discharge the sheets transported by the first transport unit to the loading section; and the upper discharge roller in a clamping position in which the sheet is clamped between the upper discharge roller and the lower discharge roller. The upper discharge roller is spaced apart from the lower discharge roller.The device comprises a first separation position and an upper discharge roller moving unit that moves the upper discharge roller to a second separation position located between the clamping position and the first separation position in the vertical direction; a sensor that detects a sheet; and a control unit configured to control the first transport unit, the second transport unit, the drive unit, the pair of discharge rollers, and the upper discharge roller moving unit based on the signal from the sensor. The control unit transports the sheet transported by the first transport unit in the second transport direction on the aforementioned placement unit, bringing the downstream end of the sheet in the second transport direction to abut the abutment unit, and by driving the drive unit, moves the sheet abutted against the abutment unit in the shift direction to position it at the binding position. This process is repeated, thereby enabling the device to move multiple sheets positioned at the binding position. A binding discharge process in which the processing unit performs the binding process and discharges the multiple sheets that have been bound by the discharge roller pair to the loading section, and a switchbackless shift discharge process in which, with the upper discharge roller in the first separation position, the sheet is transported in the first transport direction until the downstream end of the sheet in the first transport direction passes between the upper discharge roller and the lower discharge roller, then the upper discharge roller is moved from the first separation position to the second separation position to push the sheet down, then with the upper discharge roller in the second separation position, the drive unit is driven to shift the sheet in the shift direction without transporting the sheet in the second transport direction by the second transport unit, then the upper discharge roller is moved to the clamping position and the sheet is discharged to the loading section by the discharge roller pair, Selectively It is an executable sheet processing device. Another aspect of the present disclosure includes an image forming unit for forming an image on a sheet, a first transport unit for transporting the sheet on which the image has been formed by the image forming unit in a first transport direction, a placement unit for placing the sheet transported by the first transport unit, abutment unit against which the upstream end of the sheet on the placement unit in the first transport direction abuts, a second transport unit for transporting the sheet in a second transport direction toward the abutment unit, a shift unit that moves the sheet transported by the first transport unit in the shift direction by moving in a shift direction intersecting the first transport direction while in contact with one edge of the sheet transported by the first transport unit along the first transport direction, and the shift unit A drive unit that drives the shift unit to move in the shift direction; a processing unit that performs a binding process on a plurality of sheets that have been transported by the second transport unit in the second transport direction so that their downstream end in the second transport direction abuts against the stopper unit, and which have been moved by the shift unit in the shift direction to be positioned at the binding position; a loading unit that is located downstream of the above-described loading unit in the first transport direction and loads the sheets transported by the first transport unit; a pair of discharge rollers having an upper discharge roller and a lower discharge roller, configured to discharge the sheets transported by the first transport unit to the loading unit; and the upper discharge roller in a clamping position in which the sheet is clamped between the upper discharge roller and the lower discharge roller. The upper discharge roller is spaced apart from the lower discharge roller.The device comprises a first separation position and an upper discharge roller moving unit that moves the upper discharge roller to a second separation position located between the clamping position and the first separation position in the vertical direction; a sensor that detects a sheet; and a control unit configured to control the first transport unit, the second transport unit, the drive unit, the pair of discharge rollers, and the upper discharge roller moving unit based on the signal from the sensor. The control unit transports the sheet transported by the first transport unit in the second transport direction on the aforementioned placement unit, bringing the downstream end of the sheet in the second transport direction to abut the abutment unit, and by driving the drive unit, moves the sheet abutted against the abutment unit in the shift direction to position it at the binding position. This process is repeated, thereby enabling the device to move multiple sheets positioned at the binding position. A binding discharge process in which the processing unit performs the binding process and discharges the multiple sheets that have been bound by the discharge roller pair to the loading section, and a switchbackless shift discharge process in which, with the upper discharge roller in the first separation position, the sheet is transported in the first transport direction until the downstream end of the sheet in the first transport direction passes between the upper discharge roller and the lower discharge roller, then the upper discharge roller is moved from the first separation position to the second separation position to push the sheet down, then with the upper discharge roller in the second separation position, the drive unit is driven to shift the sheet in the shift direction without transporting the sheet in the second transport direction by the second transport unit, then the upper discharge roller is moved to the clamping position and the sheet is discharged to the loading section by the discharge roller pair, Selectively It is a feasible image formation system. [Effects of the Invention]

[0007] According to the present invention, the productivity of shift discharge processing can be improved at a low cost. [Brief explanation of the drawing]

[0008] [Figure 1] A schematic cross-sectional view of the image forming system according to the first embodiment. [Figure 2] A schematic cross-sectional view of the sheet processing apparatus according to the first embodiment. [Figure 3] A schematic perspective view showing the sheet processing apparatus according to the first embodiment with the upper cover removed. [Figure 4] (a) A view of the alignment plate on the processing tray as seen from the width direction, (b) A view of the alignment plate as seen from the downstream side in the sheet transport direction, and (c) A perspective view of the alignment plate according to the first embodiment. [Figure 5] (a) A perspective view of the area around the processing tray and (b) A schematic cross-sectional view of the sheet processing device in the home position according to the first embodiment. [Figure 6] A view from the width direction of (a) the discharge roller, (b) the scraping paddle, and (c) the rear end dropping member in the home position of the sheet processing apparatus according to the first embodiment. [Figure 7] A perspective view showing the engagement relationship between the rear end drop member and the scraping paddle according to the first embodiment. [Figure 8] (a) A perspective view of the area around the processing tray and (b) A schematic cross-sectional view of the sheet processing device during sheet discharge according to the first embodiment. [Figure 9] A view from the width direction of (a) the state of the discharge roller, (b) the state of the scraping paddle, and (c) the state of the rear end dropping member when a sheet is discharged from the sheet processing device according to the first embodiment. [Figure 10] (a) A perspective view of the area around the processing tray and (b) A schematic cross-sectional view of the sheet processing device during sheet scraping according to the first embodiment. [Figure 11] A view from the width direction of (a) the discharge roller, (b) the scraping paddle, and (c) the rear end dropping member during sheet scraping of the sheet processing device according to the first embodiment. [Figure 12] A table showing the correspondence between each motor and each component of the sheet processing apparatus according to the first embodiment. [Figure 13] A block diagram showing the control configuration of a sheet processing apparatus according to the first embodiment. [Figure 14] A flowchart showing an example of the control flow of a sheet processing apparatus according to the first embodiment. [Figure 15] (a) A schematic diagram of the main part of the sheet processing apparatus at the home position of the first shift discharge process according to the first embodiment, as viewed from above, and (b) a schematic cross-sectional configuration diagram. [Figure 16] (a) A schematic diagram of the main part of the sheet processing apparatus when receiving a sheet in the first shift discharge process according to the first embodiment, as viewed from above, and (b) a schematic cross-sectional configuration diagram. [Figure 17] (a) A schematic diagram of the main part of the sheet processing apparatus when the upper discharge roller descends in the first shift discharge process according to the first embodiment, as viewed from above, and (b) a schematic cross-sectional configuration diagram. [Figure 18] (a) A schematic diagram of the main part of the sheet processing apparatus when conveyance stops in the first shift discharge process according to the first embodiment, as viewed from above, and (b) a schematic cross-sectional configuration diagram. [Figure 19] (a) A schematic diagram of the main part of the sheet processing apparatus when the alignment plate moves in the first shift discharge process according to the first embodiment, as viewed from above, and (b) a schematic cross-sectional configuration diagram. [Figure 20] (a) A schematic diagram of the main part of the sheet processing apparatus when the sheet is shifted by the alignment plate in the first shift discharge process according to the first embodiment, as viewed from above, and (b) a schematic cross-sectional configuration diagram. [Figure 21] (a) A schematic diagram of the main part of the sheet processing apparatus when the sheet shift is completed in the first shift discharge process according to the first embodiment, as viewed from above, and (b) a schematic cross-sectional configuration diagram. [Figure 22] (a) A schematic diagram of the main part of the sheet processing apparatus when the alignment plate retracts in the first shift discharge process according to the first embodiment, as viewed from above, and (b) a schematic cross-sectional configuration diagram. [Figure 23] (a) A schematic diagram of the main part of the sheet processing apparatus when discharging the sheet in the first shift discharge process according to the first embodiment, as viewed from above, and (b) a schematic cross-sectional configuration diagram. [Figure 24] (a) A schematic diagram of the main part of the sheet processing apparatus when the sheet discharge is completed in the first shift discharge process according to the first embodiment, as viewed from above, and (b) a schematic cross-sectional configuration diagram. [Figure 25] (a) Schematic diagram of the main part of the sheet processing apparatus when the leading end of the sheet in the second shift discharge process according to the first embodiment has passed beyond the discharge roller, as viewed from above, and (b) schematic cross-sectional configuration diagram. [Figure 26] (a) Schematic diagram of the main part of the sheet processing apparatus when the trailing end of the sheet in the second shift discharge process according to the first embodiment has passed beyond the pre-processing roller, as viewed from above, and (b) schematic cross-sectional configuration diagram. [Figure 27] (a) Schematic diagram of the main part of the sheet processing apparatus when the sheet is being drawn in during the second shift discharge process according to the first embodiment, as viewed from above, and (b) schematic cross-sectional configuration diagram. [Figure 28] (a) Schematic diagram of the main part of the sheet processing apparatus when the return member in the second shift discharge process according to the first embodiment is descending, as viewed from above, and (b) schematic cross-sectional configuration diagram. [Figure 29] (a) Schematic diagram of the main part of the sheet processing apparatus when the trailing end dropping member, drawing paddle, and return member in the second shift discharge process according to the first embodiment are ascending, as viewed from above, and (b) schematic cross-sectional configuration diagram. [Figure 30] (a) Schematic diagram of the main part of the sheet processing apparatus when the sheet is being shifted by the alignment plate in the second shift discharge process according to the first embodiment, as viewed from above, and (b) schematic cross-sectional configuration diagram. [Figure 31] (a) Schematic diagram of the main part of the sheet processing apparatus when the sheet shift in the second shift discharge process according to the first embodiment is completed, as viewed from above, and (b) schematic cross-sectional configuration diagram. [Figure 32] (a) Schematic diagram of the main part of the sheet processing apparatus when the alignment plate in the second shift discharge process according to the first embodiment is retracted, as viewed from above, and (b) schematic cross-sectional configuration diagram. [Figure 33] (a) Schematic diagram of the main part of the sheet processing apparatus when the sheet is being discharged in the second shift discharge process according to the first embodiment, as viewed from above, and (b) schematic cross-sectional configuration diagram. [Figure 34] (a) Schematic diagram of the main part of the sheet processing apparatus when the sheet discharge in the second shift discharge process according to the first embodiment is completed, as viewed from above, and (b) schematic cross-sectional configuration diagram. [Figure 35] A schematic cross-sectional view of the image forming system according to the second embodiment. [Figure 36] A schematic perspective view of the sheet processing device according to the second embodiment. [Figure 37] (a) A schematic diagram of a sheet processing apparatus according to the second embodiment, viewed from above, and (b) a schematic diagram viewed from the side. [Figure 38] Schematic diagrams showing (a) a first example, (b) a second example, and (c) a third example of the sheet nip position of the scraping belt and discharge belt according to the second embodiment. [Figure 39] A schematic diagram showing another example of the support configuration of the scraping belt according to the second embodiment, (a) showing a state with few sheets on the processing tray, and (b) showing a state with many sheets on the processing tray. [Figure 40] A perspective view showing a part of the drive configuration according to the second embodiment. [Figure 41] A side view of the first drive configuration showing (a) the state in which nip pressure is applied to the roller before processing according to the second embodiment, and (b) the state in which the nip pressure is released. [Figure 42] A perspective view showing a part of the drive configuration according to the second embodiment. [Figure 43] A perspective view showing the drive configuration of the scraping belt and rear end drop member according to the second embodiment. [Figure 44] A perspective view showing the operation of the discharge roller according to the second embodiment, (a) showing the discharge roller in the retracted position, and (b) showing the discharge roller in the contact position. [Figure 45] A perspective view showing the operation of the scraping belt and rear end drop member according to the second embodiment, (a) showing the scraping belt and rear end drop member in the first position, and (b) showing the scraping belt and rear end drop member in the second position. [Figure 46] A perspective view showing the operation of the scraping belt and rear end drop member according to the second embodiment, (a) showing the scraping belt and rear end drop member in the second position, and (b) showing the scraping belt and rear end drop member returning from the second position to the first position. [Figure 47] A diagram illustrating another example of the support configuration for the discharge roller in the second embodiment. [Figure 48] A table showing the correspondence between each motor and each component of the sheet processing apparatus according to the second embodiment. [Figure 49] A block diagram showing the control configuration of a sheet processing apparatus according to the second embodiment. [Figure 50] (a) A schematic diagram of a sheet processing device viewed from above, and (b) a schematic diagram viewed from the side, showing the state in which the leading edge of the sheet has reached the pre-processing roller in the straight discharge mode according to the second embodiment. [Figure 51] (a) a schematic diagram of a sheet processing device viewed from above, and (b) a schematic diagram of a sheet processing device viewed from the side, showing the state after the leading edge of the sheet has passed the pre-processing roller in the straight discharge mode according to the second embodiment. [Figure 52] (a) A schematic diagram of a sheet processing device viewed from above, and (b) a schematic diagram viewed from the side, showing a state in which the sheet is nipped between the discharge roller and the discharge belt in the straight discharge mode according to the second embodiment. [Figure 53] (a) A schematic diagram of a sheet processing device viewed from above, and (b) a schematic diagram viewed from the side, showing the state in which the sheet has been discharged onto the loading tray in the straight discharge mode according to the second embodiment. [Figure 54] (a) A schematic diagram of a sheet processing device viewed from above, and (b) a schematic diagram viewed from the side, showing the state in the shift mode (productivity priority) according to the second embodiment, where the leading edge of the sheet has reached the pre-processing roller. [Figure 55] (a) A schematic diagram of a sheet processing device viewed from above, and (b) a schematic diagram viewed from the side, showing the state after the leading edge of the sheet has passed the pre-processing roller in the shift mode (productivity priority) according to the second embodiment. [Figure 56] (a) A schematic diagram of a sheet processing device viewed from above, and (b) a schematic diagram viewed from the side, showing the sheet being shifted in the shift mode (productivity priority) according to the second embodiment. [Figure 57](a) A schematic diagram of a sheet processing device viewed from above, and (b) a schematic diagram of a sheet processing device viewed from the side, showing the state in which the sheet shift is completed in the shift mode (productivity priority) according to the second embodiment. [Figure 58] (a) A schematic diagram of a sheet processing device viewed from above, and (b) a schematic diagram viewed from the side, showing the state in which the sheets have been discharged onto the loading tray in the shift mode (productivity priority) according to the second embodiment. [Figure 59] (a) A schematic diagram of a sheet processing device viewed from above, and (b) a schematic diagram viewed from the side, showing the state in which the leading edge of the sheet has reached the pre-processing roller in the shift mode (prioritizing alignment) for a large sheet according to the second embodiment. [Figure 60] (a) A schematic diagram of a sheet processing device viewed from above, and (b) a schematic diagram viewed from the side, showing the state after the rear end of the sheet has passed the pre-processing roller in the shift mode (alignment priority) for a large sheet according to the second embodiment. [Figure 61] (a) A schematic diagram of a sheet processing device viewed from above, and (b) a schematic diagram of a sheet viewed from the side, showing the sheet nipped by the scraping belt and discharge roller and discharge belt in shift mode (prioritizing alignment) for a large sheet according to the second embodiment. [Figure 62] (a) A schematic diagram of a sheet processing device viewed from above, and (b) a schematic diagram viewed from the side, showing the sheet in a state where it is abutting against a rear end restricting member in a shift mode (prioritizing alignment) for a large sheet according to the second embodiment. [Figure 63] (a) A schematic diagram of a sheet processing device viewed from above, and (b) a schematic diagram viewed from the side, showing the sheet being shifted in shift mode (prioritizing alignment) for a large sheet according to the second embodiment. [Figure 64] (a) A schematic diagram of a sheet processing device viewed from above, and (b) a schematic diagram viewed from the side, showing the state in which the sheet shift is completed in the shift mode (prioritizing alignment) for a large sheet according to the second embodiment. [Figure 65](a) A schematic diagram of a sheet processing device viewed from above, and (b) a schematic diagram viewed from the side, showing the state in which a sheet is discharged onto a loading tray in shift mode (prioritizing alignment) for a large sheet according to the second embodiment. [Figure 66] (a) A schematic diagram of a sheet processing device viewed from above, and (b) a schematic diagram viewed from the side, showing the state in which the leading edge of the sheet has reached the pre-processing roller in the stapling mode according to the second embodiment. [Figure 67] (a) A schematic diagram of a sheet processing device viewed from above, and (b) a schematic diagram viewed from the side, showing the sheet in a state where the sheet is abutted against the rear end restricting member in the stapling mode according to the second embodiment. [Figure 68] (a) A schematic diagram of a sheet processing device viewed from above, and (b) a schematic diagram viewed from the side, showing a state in which the widthwise side edge of the sheet is restricted in the stapling mode according to the second embodiment. [Figure 69] (a) A schematic diagram of a sheet processing device viewed from above, and (b) a schematic diagram of a sheet processing device viewed from the side, showing a state in which the rear end of a sheet is held down and the next sheet can be accepted in a stapling mode according to the second embodiment. [Figure 70] (a) A schematic diagram of a sheet processing device viewed from above, and (b) a schematic diagram of a sheet processing device viewed from the side, showing the state in which the second sheet is abutted against the rear end regulating member in the stapling mode according to the second embodiment. [Figure 71] (a) A schematic diagram of a sheet processing device viewed from above, and (b) a schematic diagram of a sheet processing device viewed from the side, showing a state in which the widthwise side edges of two sheets are restricted in a stapling mode according to the second embodiment. [Figure 72] (a) A schematic diagram of a sheet processing device viewed from above, and (b) a schematic diagram of a sheet processing device viewed from the side, showing a state in which multiple sheets are being stapled in the stapling mode according to the second embodiment. [Figure 73] (a) A schematic diagram of a sheet processing device viewed from above, and (b) a schematic diagram of a sheet processing device viewed from the side, showing the state in which a stapled sheet bundle is nipped between a scraping belt and a discharge roller and discharge belt in the stapling mode according to the second embodiment. [Figure 74](a) A schematic diagram of a sheet processing device viewed from above, and (b) a schematic diagram of a sheet processing device viewed from the side, showing the state in which a stack of stapled sheets is discharged onto a loading tray in the stapling mode according to the second embodiment. [Figure 75] (a) A schematic diagram of a sheet processing device viewed from above, and (b) a schematic diagram viewed from the side, showing the state in which the sheet is nipped by the discharge roller and discharge belt during the sheet discharge operation according to the second embodiment. [Figure 76] (a) A schematic diagram of the sheet processing device viewed from above, and (b) a schematic diagram of the sheet processing device viewed from the side, showing the state in which the loading tray begins to descend during the sheet discharge operation according to the second embodiment. [Figure 77] (a) A schematic diagram of a sheet processing device viewed from above, and (b) a schematic diagram of a sheet processing device viewed from the side, showing the state in which the rear end of the sheet is guided downward by the sheet holding belt during the sheet discharge operation according to the second embodiment. [Figure 78] (a) A schematic diagram of the sheet processing device viewed from above, and (b) a schematic diagram of the sheet processing device viewed from the side, showing the state in which the loading tray is raised during the sheet discharge operation according to the second embodiment. [Figure 79] (a) A schematic diagram of a sheet processing device viewed from above, and (b) a schematic diagram of a sheet processing device viewed from the side, showing the state in which the rear end of a sheet loaded on a loading tray is held down by a sheet holding belt during the sheet discharge operation according to the second embodiment. [Figure 80] A schematic cross-sectional view of a sheet processing device according to a first example of another embodiment. [Figure 81] A schematic cross-sectional view of a sheet processing device according to a second example of another embodiment. [Figure 82] A schematic cross-sectional view of a sheet processing device according to a third example of another embodiment, (a) schematic cross-sectional view of the sheet processing device at the home position of the first shift discharge process, (b) schematic cross-sectional view of the sheet processing device when the upper discharge roller of the first shift discharge process is descending, and (c) schematic cross-sectional view of the sheet processing device when the sheet is shifted by the alignment plate of the first shift discharge process. [Figure 83]A schematic diagram of a discharge arm and a second rear end drop member according to a third example of another embodiment, showing (a) the state in which the second rear end drop member is in the upper position and (b) the state in which the second rear end drop member is in the lower position. [Modes for carrying out the invention]

[0009] <First Embodiment> The first embodiment will be described using Figures 1 to 34. First, the schematic configuration of the image forming system of this embodiment will be described using Figure 1.

[0010] [Image Forming System] Figure 1 is a cross-sectional view showing the schematic configuration of the image forming system of this embodiment. The image forming system 1000A includes an image forming apparatus 100, a punch unit 150, and a sheet processing apparatus 200A. The image forming apparatus 100 is a copier, printer, facsimile, or a multifunction device having multiple of these functions, and forms an image on a sheet such as paper or a plastic sheet. In this embodiment, it is an electrophotographic printer, and the sheet on which the toner image has been formed is discharged from the first discharge unit 101 or the second discharge unit 102. Note that the image forming apparatus 100 may also be an inkjet type image forming apparatus.

[0011] In this embodiment of the image forming apparatus, although detailed illustrations are omitted, a toner image is formed on the sheet in the image forming unit 103. Briefly, the surface of the photosensitive drum is charged, and by exposing that surface, an electrostatic latent image is formed on the photosensitive drum. This electrostatic latent image is then developed with a developer in the developing unit to form a toner image. The toner image formed on the photosensitive drum is transferred to the sheet, and further fixed to the sheet by heating and pressurizing in the fixing unit. The sheet with the fixed toner image passes through the transport path 104 and is sent to the first discharge unit 101 or the second discharge unit 102.

[0012] Furthermore, the image forming apparatus 100 of this embodiment includes an image forming apparatus body 110 equipped with an image forming unit 103, a transport path 104, a first discharge unit 101 and a second discharge unit 102, and an image reading unit 120 positioned above the image forming apparatus body 110. The image reading unit 120 reads an image on a document and sends the read image signal to the image forming apparatus body 110. The image forming apparatus body 110 has a first housing section 111 in which the image forming unit 103 is located, and a second housing section 112 in which a part of the transport path 104, the first discharge unit 101 and the second discharge unit 102 are located, with the second housing section 112 positioned above the first housing section 111. The image reading unit 120 is positioned above the second housing section 112. Furthermore, the second housing section is equipped with an operation panel (not shown) that allows the user to input instructions (such as printing conditions and mode settings) for the image forming apparatus 100, punch unit 150, and sheet processing apparatus 200.

[0013] In this embodiment, the system has an internal space 130 surrounded by the first housing 111, the second housing 112, and the image reading unit 120. The sheet is discharged into the internal space 130 from either the first discharge unit 101 or the second discharge unit 102. A punch unit 150 and a sheet processing device 200A can be attached to and removed from this internal space 130. In this embodiment, the image forming system 1000A is configured by attaching the punch unit 150 and the sheet processing device 200A, but either one of them, or other sheet processing devices, may be attached instead.

[0014] The punch unit 150 is connected to the first discharge unit 101 and can receive the sheet discharged from the first discharge unit 101 and perform punching on the sheet. The sheet processing device 200A is connected to the sheet discharge unit of the punch unit 150 and can receive the sheet discharged from the punch unit 150. As will be described in detail later, it is possible to perform predetermined processing such as stapling on the sheet. It is also possible to transfer the sheet to the sheet processing device 200A without performing punching on the punch unit 150, and the sheet processing device 200A can discharge the sheet without performing predetermined processing. The sheet discharged from the second discharge unit 102 is discharged onto the sheet mounting surface 160 above the punch unit 150 and the sheet processing device 200A.

[0015] In the internal space 130 of the drum, rails 131 are arranged along the left-right direction in Figure 1, and the punch unit 150 and the sheet processing device 200 can be attached and detached along the rails 131 in the directions of arrows α1 and α2. Alternatively, the punch unit 150 can be omitted, and the sheet processing device 200A can be directly connected to the first discharge unit 101. Furthermore, by making the punch unit 150 and the sheet processing device 200A detachable in this way, sheet jamming can be handled.

[0016] For example, if a sheet jams in the first discharge section 101, the punch unit 150 and the sheet processing device 200A are pulled out in the direction of arrow α1 to expose the first discharge section 101. Also, if a sheet jam occurs in the punch unit 150, only the sheet processing device 200A is pulled out in the direction of arrow α1 to expose the punch unit 150. When mounting the punch unit 150 and the sheet processing device 200A into the image forming apparatus 100, they are pushed in in the direction of arrow α2. Thus, in this embodiment, since the sheet processing device 200A is placed in the internal space 130 of the cylinder of the image forming apparatus 100, it is required to miniaturize the sheet processing device 200A.

[0017] [Sheet processing device] The configuration of the sheet processing apparatus 200A in this embodiment will be explained using Figures 2 to 11(c). First, the overall configuration of the sheet processing apparatus 200A will be explained using Figures 2 and 3.

[0018] [Overall configuration of the sheet processing device] The sheet processing apparatus 200A includes a transport path 210A, pre-processing rollers 211A and 212A as the first transport section, a processing tray 220 as the loading section, an upper discharge roller (nip member) 230A and a lower discharge roller 230B as a pair of discharge rotating bodies (discharge section), a scraping paddle 240A as the second transport section, a rear end dropping member 250A as the sheet dropping section, a matching section 270A as the first and second shift sections, a return member 280, a rear end regulating member 290 as the abutting section, a loading tray 300 as the loading section, a sheet pressing paddle 320A, and the like. Sheets received from the image forming apparatus 100 or punch unit 150 are transported to the transport path 210A.

[0019] The sheets transported from the transport path 210A are either directly discharged to the loading tray 300 or placed on the processing tray 220, depending on the mode of processing the sheets. Direct discharge to the loading tray 300 means that the sheets are discharged to the loading tray 300 without being transported back to a position on the processing tray 220 where stapling can be performed. In other words, the sheet processing device 200A has a mode in which sheets that have been stapled by the stapling unit 400 are discharged to the loading tray 300, and a mode in which sheets are discharged to the loading tray 300 without stapling by the stapling unit 400. In this embodiment, sheet alignment is made possible by the alignment unit 270A without placing the sheets on the processing tray 220. Sheet alignment is also possible on the processing tray 220, and stapling is made possible on sheets placed on the processing tray 220 by the stapling unit 400. Furthermore, the sheets or sheet bundles placed on the processing tray 220 are connected to a pair of discharge rotating bodies (Discharge rollers) The contents can be discharged onto the loading tray 300 via the upper discharge roller 230A and the lower discharge roller 230B. The configuration of each part will be explained in detail below.

[0020] [Transport path] The transport path 210A is a path for transporting the sheet in a first transport direction (a predetermined direction), and includes an upper guide 2101 that guides the upper surface of the sheet being transported, and a lower guide 2102 that guides the lower surface of the sheet. The transport path 210A is arranged with pre-processing rollers 211A, 212A and upstream rollers (inlet rollers) 213a, 213b as a first transport section (a pair of transport rotating bodies). These are arranged in pairs so as to be spaced apart in the width direction of the sheet (arrow γ direction in Figure 3) that intersects the sheet transport direction (first transport direction, arrow β direction in Figure 2 (left-right direction)).

[0021] The pre-processing rollers 211A and 212A are a first conveying section and a pair of conveying rotating bodies that convey the sheet, with at least one rotating while gripping the sheet. The upstream rollers 213a and 213b also grip the sheet, with at least one rotating while gripping the sheet. The upstream rollers 213a and 213b are located at the entrance of the sheet processing device 200A, receiving the sheet conveyed from the upstream side of the sheet processing device 200A and conveying it to the conveying path 210A. The sheet that has passed through the conveying path 210A then reaches the pre-processing rollers 211A and 212A.

[0022] The pre-processing rollers 211A and 212A form a pre-processing nip section 211a capable of gripping and conveying the sheet. The sheet is then gripped by the pre-processing nip section 211a and conveyed in the first conveying direction, and the sheet is discharged from the conveying path 210A. As will be described later, the pre-processing rollers 211A and 212A can be brought into contact with each other, separated, or the nip pressure can be changed.

[0023] [Processing tray] The processing tray 220, which serves as the sheet placement section, is positioned downstream of the sheet transport direction (first transport direction) of the transport path 210A and vertically below the transport path 210. The processing tray 220 is also inclined with respect to the horizontal plane such that the upstream side in the first transport direction is lower than the downstream side. The processing tray 220 temporarily places sheets that have been transported downstream in the first transport direction by the pre-processing rollers 211A and 212A. The processing tray 220 can also stack multiple sheets, and the alignment section 270A on the processing tray 220 aligns the sheets in the width direction and moves them in the width direction (sheet shifting). At the upstream end of the processing tray 220 in the first transport direction, there is a rear end regulating member 290 which acts as a stopper against which the upstream edge of the sheet in the first transport direction (the downstream edge in the second transport direction, opposite to the first transport direction, the rear end of the sheet) of the sheet placed on the processing tray 220 abuts. Furthermore, a portion of the processing tray 220 (for example, the downstream end in the first transport direction) may protrude vertically upward from the transport path 210A.

[0024] Furthermore, a stapling unit 400, which functions as a processing unit, is positioned upstream of the processing tray 220 in the first transport direction. The stapling unit 400 performs a predetermined stapling process (binding process) on the sheet bundles that have been aligned in the width direction and restricted at the rear end by the processing tray 220. The stapling unit 400 can change the stapling position on the sheet bundle and moves according to the stapling position. Note that the predetermined process may be other processes such as punching, in addition to stapling. The sheets or sheet bundles placed on the processing tray 220 are discharged to the loading tray 300 by the upper discharge roller 230A and the lower discharge roller 230B, as described later.

[0025] [Paddle for digging] The scraping paddle 240A, which serves as the second conveying unit, conveys the sheets on the processing tray 220 in a second conveying direction opposite to the first conveying direction (switchback conveying). The scraping paddle 240A has a paddle section 2401 as a rotating member, a paddle arm 2402 as a support section that supports the paddle section 2401, and a pivot point 2403 that pivotably supports the paddle arm 2402. That is, the paddle arm 2402 is pivotable in the vertical direction around the pivot point 2403, and the paddle section 2401 is rotatably mounted at the tip of the paddle arm 2402.

[0026] Such a scraping paddle 240A can swing around a pivot point 2403 between a return position in which the paddle portion 2401 contacts the upper surface of the sheet on the processing tray 220 and the sheet can be transported in the second transport direction, and an upper retracted position in which the paddle portion 2401 is retracted above the return position. The pivot point 2403 is located upstream in the first transport direction from the pre-processing nip portion 211a, which is the nip position where the sheet is gripped by the pre-processing rollers 211A and 212A, and vertically above the pre-processing nip portion 211a. The paddle arm 2402 extends downstream from the pivot point 2403 in the first transport direction, and the paddle portion 2401 is provided at its tip. Furthermore, as shown in Figure 3, a pair of scraping paddles 240A are arranged on both sides in the width direction of the upper discharge roller 230A, which will be described later.

[0027] [Rear end drop member] The rear end dropping members 250A, which serve as sheet dropping sections, are provided in pairs on both sides of the pair of scraping paddles 240A. That is, the pair of rear end dropping members 250A are positioned on both sides of the scraping paddles 240A in the width direction and, as will be described later, move vertically in conjunction with the scraping paddles 240A, so as to contact the upper surface on the upstream side in the first conveying direction of the sheet and operate to drop the upstream end (rear end) of the sheet toward the processing tray 220. The rear end dropping members 250A may also be driven independently of the scraping paddles 240A.

[0028] Such a rear end drop member 250A has a pivot axis 2501 as the pivot center downstream in the first transport direction from the pair of pre-processing rollers 211A and 212A, which act as transport rollers. It extends upstream from the pivot axis 2501 in the first transport direction and is rotatable around the pivot axis 2501 from an upper position above the pre-processing rollers 211A and 212A to a lower position below the pre-processing rollers 211A and 212A. By rotating from the upper position to the lower position, the rear end drop member 250A contacts the sheet transported by the pre-processing rollers 211A and 212A from above, dropping the sheet into the processing tray 220 below.

[0029] [Return component] The return member 280 further transports the sheet, which has been conveyed toward the rear end restricting member 290 by the scraping paddle 240A as described above, toward the rear end restricting member 290, and restricts the position of the rear end of the sheet by bringing the rear end of the sheet into contact with the rear end restricting member 290. Such a return member 280 is made of a knurled belt 281, and by rotating the knurled belt 281, it further scrapes the sheet that has been conveyed toward the upstream side in the first transport direction by the scraping paddle 240A, bringing the rear end into contact with the rear end restricting member 290. The return member 280 is movable between a contact position where it can contact the sheet and a retracted position moved upward from the contact position. When transporting the sheet toward the rear end restricting member 290, it moves to the contact position, and when transporting the sheet on the processing tray 220 toward the loading tray 300, it moves to the retracted position.

[0030] [Discharge roller] The upper discharge roller 230A and the lower discharge roller 230B constitute a pair of discharge rotating bodies and a discharge section, and discharge the sheet that has been conveyed downstream in the first conveying direction by the pre-processing rollers 211A and 212A to a point downstream in the first conveying direction from the processing tray 220. The upper discharge roller 230A is movable between a clamping position (contact position) in which it clamps the sheet between itself and the lower discharge roller 230B, and a retracted position which is retracted upward from the clamping position, and clamps the sheet between itself and the lower discharge roller 230B in the clamping position. That is, the upper discharge roller 230A functions as a nipping member that nips the sheet between itself and the lower discharge roller 230B in the clamping position. The upper discharge roller 230A and the lower discharge roller 230B are each arranged in pairs spaced apart in the width direction of the sheet. In this embodiment, they are arranged inside the width direction of the pair of scraping paddles 240A.

[0031] The upper discharge roller 230A and the lower discharge roller 230B grip a sheet or sheet bundle at the gripping position, and the gripped sheet or sheet bundle is conveyed by the rotation of the lower discharge roller 230B, for example. The upper discharge roller 230A is a driven roller that rotates in accordance with the rotation of the lower discharge roller 230B, but it may also be driven. That is, in this embodiment, the upper discharge roller 230A is the driven rotating body, and the lower discharge roller 230B is the driving rotation. The upper discharge roller 230A also functions as a nip member that can grip a sheet between itself and the lower discharge roller 230B at the gripping position, but this nip member may be another rotating body such as a belt instead of a roller, or it may be a contact member that contacts the sheet without rotating, such as a lever member. The lower discharge roller 230B may be a rotating body other than a roller, such as a belt.

[0032] The upper discharge roller 230A is rotatable around the pivot axis 2301 between the gripping position and the retracted position. In other words, the upper discharge roller 230A is vertically movable between the gripping position and the retracted position. The upper discharge roller 230A is provided at the tip of the discharge arm 2302, which serves as a support. The pivot axis 2301 is provided coaxially with the aforementioned pivot point 2403 and is located upstream in the first conveying direction from the pre-processing nip section 211a, which grips the sheet with the pre-processing rollers 211A and 212A, and vertically above the pre-processing nip section 211a. The discharge arm 2302 extends downstream from the pivot axis 2301 in the first conveying direction, and the upper discharge roller 230A is provided at its tip. The pivot shaft 2301 does not necessarily have to be coaxial with the pivot point 2403, but in this embodiment, the pivot shafts of the upper discharge roller 230A and the scraping paddle 240A are coaxial.

[0033] The pivot shaft 2301 is positioned upstream in the first conveying direction from the discharge nip section where the upper discharge roller 230A nips the sheet between itself and the lower discharge roller 230B in the clamping position. Furthermore, in the retracted position, the upper discharge roller 230A is positioned vertically above the pre-processing nip section 211a where it nips the sheet with the pre-processing rollers 211A and 212A, and the pivot shaft 2301 is positioned vertically above the center of the upper discharge roller 230A in the retracted position.

[0034] As described above, the upper discharge roller 230A has a positional relationship with the pivot axis 2301 and the pre-processing nip portion 211a, so when it is in the retracted position, it allows the sheet that has passed the pre-processing nip portion 211a to move toward the loading tray 300. On the other hand, the upper discharge roller 230A moves downward from the retracted position toward the clamping position by rotating counterclockwise around the pivot axis 2301 in Figure 2. When the upper discharge roller 230A moves toward the clamping position, the sheet can be clamped between the upper discharge roller 230A and the lower discharge roller 230B.

[0035] [Matching part] The alignment section 270A, which functions as a shift section, will be described with reference to Figures 4(a) to 4(c), in addition to Figures 2 and 3. The alignment section 270A moves in the shift direction (width direction) intersecting the first conveying direction while in contact with the edge of the sheet that has been conveyed downstream in the first conveying direction by the pre-processing rollers 211A and 212A along the first conveying direction. Such an alignment section 270A has a pair of alignment plates 271A, which are a first shift section and a second shift section, arranged to face each other with respect to the shift direction.

[0036] The pair of alignment plates 271A are positioned further downstream than the downstream end of the first transport direction of the transport path 210A, and move in the width direction to contact the widthwise edge of the sheet, thereby aligning the sheet in the width direction. In this embodiment, they are positioned on both sides in the width direction of the sheet placed on the processing tray 220, and are movable in the width direction. The pair of alignment plates 271A also extend from the upstream side to the downstream side in the first transport direction relative to the upper discharge roller 230A and the lower discharge roller 230B. The configuration of the pair of alignment plates 271A is the same. The pair of alignment plates 271A move in the shift direction by the drive of the front (F side) alignment plate moving motor MT16 and the rear (R side) alignment plate moving motor MT17 (see Figure 12), which serve as the first and second drive units. In the first shift discharge process (switchbackless shift discharge process) and the second shift discharge process (switchback shift discharge process) described later, the matching plate on the upstream side in the shift direction is designated as the first shift section, and the matching plate on the downstream side in the shift direction is designated as the second shift section. Furthermore, the motor that drives the first shift section is designated as the first drive section, and the motor that drives the second shift section is designated as the second drive section.

[0037] The matching plate 271A is formed so that its vertical width is wider on the downstream side in the first conveying direction. That is, the matching plate 271A has a first plate portion 2701 on the downstream side in the first conveying direction and a second plate portion 2702 formed to be continuous with the first plate portion 2701 on the upstream side in the first conveying direction. The first plate portion 2701 has a larger vertical area than the second plate portion 2702 so that it can come into contact with the sheet even if the leading edge of the conveyed sheet is curled upward or downward. On the other hand, the second plate portion 2702 is formed so that its vertical height is lower than that of the first plate portion 2701 so that it does not interfere with the rear end drop member 250A even if the rear end drop member 250A is in a lower position. In addition, the upper edge of the second plate portion 2702 is inclined so that it becomes lower as it is directed towards the upstream side in the first conveying direction.

[0038] Furthermore, the first plate portion 2701 is formed to span from the upstream to the downstream side in the first transport direction with respect to the upper discharge roller 230A and the lower discharge roller 230B. This ensures that at least the first plate portion 2701 can contact the sheet even when the sheet is discharged by the first shift discharge process described later. The second plate portion 2702 is located on the processing tray 220 and is formed continuously with respect to the first plate portion 2701 in the first transport direction. This ensures that at least the second plate portion 2702 can contact the sheet placed on the processing tray 220 by the second shift discharge process described later.

[0039] Furthermore, the first plate portion 2701 has a curl-holding portion 2703 and a support portion 2704, as shown in Figures 4(a) to 4(c). The curl-holding portion 2703 is located downstream in the first conveying direction from the discharge nip portion 230a (see Figure 8(b), described later), which is the nip position where the sheet is held between the upper discharge roller 230A and the lower discharge roller 230B, and is also located vertically above the discharge nip portion 230a, and holds down the leading edge of the sheet that has curled upward. In this embodiment, the curl-holding portion 2703 is a projection that protrudes inward in the width direction from the upper end of the first plate portion 2701 (the side that contacts the sheet, the right side in Figure 4(b)), and the leading edge of the curled sheet in the width direction contacts it, thereby holding down the leading edge of the sheet. Furthermore, a grooved portion 2705 is provided below the curl-holding portion 2703, and depending on the curl state, the widthwise edge of the sheet can catch on this grooved portion 2705, making it possible to hold down the tip of the curled sheet.

[0040] The support portion 2704 is located downstream in the first conveying direction from the discharge nip portion 230a, which is the nip position where the sheet is gripped by the upper discharge roller 230A and the lower discharge roller 230B, and is also located vertically below the discharge nip portion 230a, thereby supporting the sheet from below. In this embodiment, the support portion 2704 is a projection that protrudes inward in the width direction from the lower end of the first plate portion 2701 (the side that contacts the sheet, the right side in Figure 4(b)). Furthermore, as shown in Figures 4(a) and 4(c), the downstream end of the support portion 2704 in the first conveying direction has an inclined portion 2704a that slopes downward as it goes downstream. This allows the sheet supported by the support portion 2704 to be smoothly guided to the loading tray 300. Furthermore, by supporting the sheet downstream of the discharge nip section 230a in the first conveying direction with the support section 2704, the area in which the pair of matching plates 271A contact the side edge of the sheet can be increased compared to when they are not supported.

[0041] [Loading tray] As described above, the loading tray 300, which serves as the loading section, loads the sheets discharged by the upper discharge roller 230A and the lower discharge roller 230B. The loading tray 300 is located downstream of the processing tray 220 in the first transport direction and is provided so as to be able to move up and down vertically. Furthermore, the loading tray 300 is inclined with respect to the horizontal plane such that the upstream side in the first transport direction is lower than the downstream side. Such a loading tray 300 is supported so as to be able to move vertically along rails arranged in the vertical direction, and moves up and down by driving the loading tray lifting motor MT20 (Figure 12), which serves as the lifting means.

[0042] At the upstream end of the loading tray 300 in the first transport direction, there is a vertical surface 310a, which serves as a loading-side restricting means for restricting the upstream end (rear end) of a sheet or sheet bundle loaded on the loading tray 300 in a predetermined direction, and a rear end retainer 310b for pressing down on the rear end of a sheet that is in contact with the vertical surface 310a. The rear end retainer 310b is inclined toward the downstream side in the first transport direction as it extends upward, so that even if the rear end of a sheet is curled upward, it can be pressed down by this rear end retainer 310b. In addition, a sheet pressing paddle 320A is provided coaxially with the rotation axis of the lower discharge roller 230B.

[0043] The loading tray 300 can be raised and lowered by the loading tray lifting motor MT20, from a first loading position to a second loading position which is lower than the first loading position. The second loading position is the position where the loading tray 300, which was descending when discharging sheets onto the loading tray 300, switches to an upward movement. When discharging sheets, the loading tray 300 moves up and down, and the sheet-holding paddle 320A rotates, pressing down on the sheets or bundles of sheets on the loading tray 300 with the sheet-holding paddle 320A.

[0044] [Drive system configuration for each part] Next, the drive configuration of the upper discharge roller 230A, the scraping paddle 240A, and the rear end drop member 250A will be explained using Figures 5(a) to 11(c). In this embodiment, the upper discharge roller 230A, the scraping paddle 240A, and the rear end drop member 250A are configured to interlock with each other. As shown in Figure 5(a), this drive configuration 600 includes a processing motor 610 (MT12, Figure 12) as a drive source, a drive transmission mechanism 611, a rotating shaft 612, and a cam mechanism 613. The processing motor 610 can rotate in both forward and reverse directions, and the drive of the processing motor 610 is transmitted to the rotating shaft 612 via the drive transmission mechanism 611. In this embodiment, the drive transmission mechanism 611 is configured with a gear train, but other drive transmission configurations, such as a configuration that transmits drive by a belt, may also be used.

[0045] The rotating shaft 612 is positioned above the upper discharge roller 230A, the scraping paddle 240A, and the rear end drop member 250A, extending in the width direction. The rotation of the rotating shaft 612 causes the cam mechanism 613 to operate. The cam mechanism 613 has a first cam member 620 and a second cam member 630 that rotate together with the rotating shaft 612. The first cam member 620 is positioned between the pair of upper discharge rollers 230A and operates the upper discharge rollers 230A. The second cam member 630 is provided adjacent to each of the pair of scraping paddles 240A and operates the scraping paddles 240A and the rear end drop member 250A.

[0046] As shown in Figure 6(a), the first cam member 620 has a groove 621 formed on its inner side, into which a projection 2303 provided on the discharge arm 2302 of the upper discharge roller 230A can enter. The outer circumferential surface of the groove 621, i.e., the inner circumferential surface of the first cam member 620, is the inner cam surface 622. The inner cam surface 622 is a cam surface whose distance from the rotation center of the rotation shaft 612 differs depending on the phase in the rotation direction. The outer circumferential surface of the first cam member 620 is the outer cam surface 623. The outer cam surface 623 is also a cam surface whose distance from the rotation center of the rotation shaft 612 differs depending on the phase in the rotation direction.

[0047] The discharge arm 2302 of the upper discharge roller 230A has a contact portion 2304 that can contact the outer cam surface 623 of the first cam member 620, in addition to the projection 2303 described above. By rotating together with the rotation shaft 612, the first cam member 620 changes the contact position (phase) between the inner cam surface 622 and the projection 2303, or separates them, and changes the contact position (phase) between the outer cam surface 623 and the contact portion 2304, or separates them, thereby rotating the upper discharge roller 230A around the rotation shaft 2301 from the clamping position to the retracted position, as will be described later.

[0048] As shown in Figure 6(b), the second cam member 630 has a groove 631 formed on its inner side, into which the first projection 2404 provided on the paddle arm 2402 of the scraping paddle 240A can enter. The outer circumferential surface of the groove 631, i.e., the inner circumferential surface of the second cam member 630, is the inner cam surface 632. The inner cam surface 632 is a cam surface whose distance from the rotation center of the rotation axis 612 differs depending on the phase in the rotation direction. By rotating together with the rotation axis 612, the second cam member 630 changes the contact position (phase) between the inner cam surface 632 and the first projection 2404, thereby rotating the scraping paddle 240A around the pivot point 2403 from the return position to the upward retracted position, as will be described later.

[0049] Furthermore, the support portion 2406, which pivots together with the paddle arm 2402 of the scraping paddle 240A around the pivot point 2403 and supports the end of the rotation axis 2401a of the paddle portion 2401, is provided with a second projection 2405 that can enter an engaging recess 2502 formed in the rear end drop member 250A, as shown in Figures 6(c) and 7. The engaging recess 2502 contacts or separates from the second projection 2405, and in conjunction with the rotation of the scraping paddle 240A, it rotates the rear end drop member 250A around the rotation axis 2501 from an upper position to a lower position. The driving of the upper discharge roller 230A, the scraping paddle 240A, and the rear end drop member 250A will be described in detail below.

[0050] [Home position] First, Figures 5(a) to 6(c) show the home position (HP) of the upper discharge roller 230A, the scraping paddle 240A, and the rear end drop member 250A. In the home position, as shown in Figures 5(a) and (b), the upper discharge roller 230A is in the retracted position, the scraping paddle 240A is in the upward retracted position, and the rear end drop member 250A is in the upward position.

[0051] In this state, as shown in Figure 6(a), the projection 2303 of the upper discharge roller 230A contacts the inner cam surface 622 of the first cam member 620 at a position close to the center of the rotation axis 612, thereby supporting the upper discharge roller 230A on the first cam member 620.

[0052] Furthermore, as shown in Figure 6(b), the scraping paddle 240A is supported by the second cam member 630 because the first projection 2404 of the scraping paddle 240A contacts the inner cam surface 632 of the second cam member 630 at a position close to the center of the rotation axis 612.

[0053] Furthermore, as shown in Figure 6(c), the rear end drop member 250A is supported by the scraping paddle 240A via the second projection 2405, as the engaging recess 2502 of the rear end drop member 250A abuts against the second projection 2405 of the scraping paddle 240A.

[0054] [Lower discharge roller] Next, the operation of moving the upper discharge roller 230A from the home position (retracted position) to the clamping position will be explained using Figures 8(a) to 9(c). In order to lower the upper discharge roller 230A from the home position, the processing motor (Upper discharge roller moving section) When 610 is driven to rotate the rotating shaft 612 in the first direction (counterclockwise in Figures 9(a) and (b)), the first cam member 620 also rotates in the same direction, and the projection 2303 moves along the inner cam surface 622. The inner cam surface 622 is formed such that when it rotates counterclockwise from its home position, the distance from the center of the rotating shaft 612 increases. As a result of this movement, the upper discharge roller 230A descends.

[0055] Next, when the upper discharge roller 230A moves to the clamping position and contacts the lower discharge roller 230B, as shown in Figure 9(a), the inner cam surface 622 and projection 2303 of the first cam member 620 separate, and the outer cam surface 623 comes into contact with the contact portion 2304. By bringing the outer cam surface 623 into contact with the contact portion 2304 in this way, the upper discharge roller 230A is pressurized toward the lower discharge roller 230B, thereby applying a predetermined nip pressure between these rollers.

[0056] In this case, the second cam member 630 also rotates together with the rotation shaft 612, but as shown in Figure 9(b), the distance from the center of the rotation shaft 612 to the position where the inner cam surface 632 contacts the first projection 2404 is approximately the same as the distance in the home position. Therefore, even when the second cam member 630 rotates, the scraping paddle 240A is maintained in the home position. Because the scraping paddle 240A is maintained in the home position, the rear end drop member 250A is also maintained in the home position, as shown in Figure 9(c). That is, in this state, as shown in Figure 8(b), the upper discharge roller 230A moves to the clamping position, but the scraping paddle 240A and the rear end drop member 250A are maintained in the home position.

[0057] When raising the upper discharge roller 230A, the motor 610 is driven to rotate the rotating shaft 612 in a second direction opposite to the first direction (counterclockwise in Figures 9(a) and (b)). As a result, the first cam member 620 rotates in the same direction as the rotating shaft 612, causing the projection 2303 to move along the inner cam surface 622, and the upper discharge roller 230A rises. Then it returns to the home position shown in Figure 6(a).

[0058] Here, when the scraping paddle 240A and the rear end drop member 250A return from the state shown in Figures 9(b) and (c) to the state shown in Figures 6(b) and (c), the first projection 2404 moves along the inner cam surface 632 of the second cam member 630. However, the inner cam surface 632 is formed such that the distance from the center of the rotation axis 612 to the position where the inner cam surface 632 contacts the first projection 2404 does not change. Therefore, the scraping paddle 240A remains in its home position. Because the scraping paddle 240A is maintained in its home position, the rear end drop member 250A also remains in its home position.

[0059] [Lowering of the scraping paddle and the rear end drop member] Next, the operation of moving the scraping paddle 240A and the rear end dropping member 250A from the home position (upper retracted position, upper position) to the return position and lower position will be explained using Figures 10(a) to 11(c). In order to lower the scraping paddle 240A and the rear end dropping member 250A from the home position, the motor 610 is driven to rotate the rotation shaft 612 in a second direction opposite to the first direction (clockwise in Figures 11(a) and (b)). As a result, the first cam member 620 also rotates in the same direction, and the projection 2303 moves along the inner cam surface 622. The inner cam surface 622 is formed such that the distance from the center of the rotation shaft 612 remains almost unchanged even when rotated clockwise from the home position. Therefore, as shown in Figure 11(a), the upper discharge roller 230A is maintained in the home position.

[0060] Meanwhile, the second cam member 630 also rotates in the same direction as the rotation shaft 612, causing the first projection 2404 to move along the inner cam surface 632. The inner cam surface 632 is formed such that when it rotates clockwise from the home position, its distance from the center of the rotation shaft 612 increases. As a result of this movement, the scraping paddle 240A descends and moves to the return position.

[0061] At this time, the rear end drop member 250A also descends together with the scraping paddle 240A. In this embodiment, the rear end drop member 250A has a positioning portion 2503 that, when rotated from an upper position to a lower position, engages with the upper guide 2101 of the transport path 210A to position it in the lower position. The positioning portion 2503 is provided at the upper end of a protruding portion 2504 that is provided to protrude upward from the tip of the rear end drop member 250A (the upstream end in the first transport direction). The protruding portion 2504 also serves to restrict the leading edge of the sheet being transported toward the pre-processing nip portion 211a, upstream of the pre-processing nip portion 211a in the first transport direction, when the rear end drop member 250A is in the lower position.

[0062] The positioning portion 2503 is an engaging portion provided at the upper end of the protrusion 2504 so as to be able to engage with the upper guide 2101, and by contacting the upper surface of the upper guide 2101, it restricts the rear end drop member 250A from descending any further. The engaging recess 2502 is formed to be separated from the second projection 2405 in this state. Therefore, the rear end drop member 250A is in a state where it is disengaged from the scraping paddle 240A and is positioned in a lower position by the positioning portion 2503.

[0063] As a result, even when the scraping paddle 240A reaches the return position, the rear end drop member 250A does not descend further due to the engagement between the positioning part 2503 and the upper guide 2101, and is positioned in the lower position. In this state, as shown in Figure 10(b), the scraping paddle 240A and the rear end drop member 250A move to the return position and the lower position, and the upper discharge roller 230A moves to the home position.

[0064] Note that the aforementioned protrusion 2504 and positioning portion 2053 shown in Figure 11(c) are omitted from Figures 1 to 10(b). Such protrusions 2504 and positioning portion 2053 may be omitted, in which case another positioning mechanism may be provided to position the rear end drop member 250A to a lower position. For example, positioning may be performed by the engagement of the engagement recess 2502 and the second projection 2405 at the lower position.

[0065] When raising the scraping paddle 240A and the rear end drop member 250A, the motor 610 is driven to rotate the rotating shaft 612 in the first direction (counterclockwise in Figures 11(a) and (b)). As a result, the second cam member 630 rotates in the same direction as the rotating shaft 612, causing the first projection 2404 to move along the inner cam surface 632, and the scraping paddle 240A rises. At this time, the second projection 2405 re-engages with the engagement recess 2052, and this engagement also raises the rear end drop member 250A. Then, the scraping paddle 240A and the rear end drop member 250A return to the home position shown in Figures 5(a) to 6(c).

[0066] Here, when the upper discharge roller 230A returns from the state shown in Figure 11(a) to the state shown in Figure 6(a), the projection 2303 moves along the inner cam surface 622 of the first cam member 620. However, the inner cam surface 622 is formed such that the distance from the center of the rotation axis 612 to the position where the inner cam surface 622 contacts the projection 2303 does not change. Therefore, the upper discharge roller 230A remains in its home position.

[0067] In this embodiment, when the rotating shaft 612 is rotated counterclockwise from the home position as shown in Figures 6(a) to 6(c), the upper discharge roller 230A descends, and the scraping paddle 240A and the rear end dropping member 250A are maintained in the home position. On the other hand, when the rotating shaft 612 is rotated clockwise from the home position as shown in Figures 6(a) to 6(c), the upper discharge roller 230A is maintained in the home position, and the scraping paddle 240A and the rear end dropping member 250A descend.

[0068] Furthermore, when the upper discharge roller 230A is in the clamping position shown in Figure 9(a), rotating the rotation shaft 612 clockwise as shown in Figures 9(a) to 9(c) causes the upper discharge roller 230A to rise, and the scraping paddle 240A and the rear end dropping member 250A are maintained in the home position. On the other hand, when the scraping paddle 240A and the rear end dropping member 250A are in the return position and the lower position, rotating the rotation shaft 612 counterclockwise as shown in Figures 11(a) to 11(c) causes the upper discharge roller 230A to be maintained in the home position, and the scraping paddle 240A and the rear end dropping member 250A to rise.

[0069] Figure 12 shows the relationship between each motor and each component. The columns in Figure 12, from left to right, show the number, motor name, drive component, operation, direction of operation in forward rotation, and direction of operation in reverse rotation. In Figure 12, the processing motor MT12 is the processing motor 610 mentioned above. As is clear from Figure 12, the conveying motor MT11 drives either of the upstream rollers (inlet rollers) 213a and 213b, either of the pre-processing rollers 211A and 212A, the scraping paddle 240A, and the return member 280.

[0070] In addition, the processing motor MT12 raises and lowers the scraping paddle 240A, the rear end drop member 250A, and the upper discharge roller (nip member) 230A. In this embodiment, in addition to the above, there is also a return lifting motor MT13 for raising and lowering the return member 280, a discharge roller motor MT14 for driving the upper discharge roller 230A, a sheet presser motor MT15 for driving the sheet presser (bundle presser) paddle 320A, an F-side alignment plate moving motor MT16 for moving the front alignment plate 271A in the width direction (lateral movement), an R-side alignment plate moving motor MT17 for moving the rear alignment plate 271A in the width direction (lateral movement), an STP moving motor MT18 for moving the staple unit (STP) 400 to change the staple position, an STP motor MT19 for driving the staple unit 400 to staple the sheet bundle, and a loading tray lifting motor MT20 for raising and lowering the loading tray 300.

[0071] [Control configuration for sheet processing device] The control configuration of the sheet processing apparatus 200A will be explained using Figures 13 and 14. Figure 13 is a block diagram showing the motors and sensors of the sheet processing apparatus 200A. The signals from these sensors are input to the control unit 203, which acts as a control means, and each motor is controlled by the control unit 203. The control unit 203 is connected to the control unit of the image forming apparatus 100 in a communication manner and controls the entire sheet processing apparatus 200A.

[0072] Such a control unit 203 includes a CPU (Central Processing Unit), ROM (Read Only Memory), and RAM (Random Access Memory). The CPU controls each part while reading programs corresponding to control procedures stored in ROM. The RAM stores working data and input data, and the CPU performs control by referring to the data stored in RAM based on the aforementioned programs, etc.

[0073] The motors shown in Figure 13 are as described above. On the other hand, each sensor will be explained with reference to Figure 2. First, the inlet sensor SN11 is installed on the transport path 210A and detects the leading edge of the sheet being transported on the transport path 210A. The processing HP sensor SN12 detects the home positions of the scraping paddle 240A, the rear end drop member 250A, and the upper discharge roller (nip member) 230A. The return lifting HP sensor SN13 detects the home position of the return member 280 (the position after it has been moved away from the processing tray 220). The processing tray sheet detection sensor SN14 detects the presence or absence of a sheet on the processing tray 220. The sheet press HP sensor SN15 detects the home position of the sheet press paddle 320A.

[0074] The F-side alignment plate HP sensor SN16 and the R-side alignment plate HP sensor SN17 detect that the front alignment plate 271A and the rear alignment plate 271A, respectively, are in a position (home position) separated in the width direction from the sheet placed on the processing tray 220. The stapler movement HP sensor SN18 detects that the staple unit 400 is in the home position. The sheet detection sensor SN19 detects the topmost sheet placed on the loading tray 300. The loading tray encoder sensor SN20 detects the vertical position of the loading tray 300. The loading tray lower limit position detection sensor SN21 detects the lower limit position of the loading tray 300. The control unit 203 performs the following controls based on the signals from each of these sensors.

[0075] Next, the control flow for each mode of this embodiment will be explained using Figure 14. In this embodiment, there is a straight discharge mode in which the sheets sent to the sheet processing device 200A are discharged directly to the loading tray 300 without any predetermined processing; a shift mode in which the sheets sent to the sheet processing device 200A are moved in the width direction (shift operation) before being discharged to the loading tray 300 in order to separate the sheets discharged to the loading tray 300; and a staple mode in which the sheets sent to the sheet processing device 200A are stapled as a predetermined processing before being discharged to the loading tray 300. Each of these modes is selected by the user through the operation panel of the image forming apparatus 100 or a PC connected via a network, etc.

[0076] In this embodiment, both manual mode setting by the user and automatic mode setting based on paper type (sheet length) are possible. In shift mode, the user can appropriately set whether to select the first shift discharge process or the second shift discharge process, as described later, depending on the desired output.

[0077] In the stapling mode, which is the binding discharge process, the sheets conveyed downstream in the first transport direction by the pre-processing rollers 211A and 212A are conveyed in the second transport direction by the scraping paddle 240A on the processing tray 220, so that the downstream edge (rear end) of the sheet in the second transport direction abuts against the rear end restricting member 290, that is, the rear end of the sheet is restricted. Then, by driving the alignment section 270A (a pair of alignment plates 271A) with the F-side alignment plate moving motor MT16 and the R-side alignment plate moving motor MT17, the sheet that has abutted against the rear end restricting member 290 is moved by the alignment section 270A in the sheet width direction (same direction as the shift direction) and positioned at the stapling position. That is, alignment processing is performed. In this embodiment, center alignment is performed, and the sheet is struck from both sides in the sheet width direction using the pair of alignment plates 271A to perform alignment. By repeating this operation of restricting the rear end of the sheet and the alignment processing, a sheet bundle is formed on the processing tray 220. Subsequently, the sheet bundle positioned at the binding position is stapled, and the stapled sheet bundle is discharged to the loading tray 300 by the upper discharge roller 230A and the lower discharge roller 230B. In the following shift mode, the pair of alignment plates 271A used in the alignment process during sheet bundle formation in this stapling mode, along with the F-side alignment plate moving motor MT16 and the R-side alignment plate moving motor MT17, are used to perform a shift operation for sheets that are not to be stapled.

[0078] Furthermore, the shift mode includes two cases: one in which the sheet is shifted to a sheet whose length in the first transport direction (first transport direction) is a first length (first sheet, small-sized sheet), and another in which the sheet is shifted to a sheet whose length in the first transport direction is longer than the first length (second sheet, large-sized sheet). A small-sized sheet is, for example, a sheet whose length in the first transport direction is less than or equal to a predetermined length, and a large-sized sheet is, for example, a sheet whose length in the first transport direction is longer than a predetermined length. The predetermined length is, for example, the so-called A4 portrait size, where A4 size paper is fed vertically (the direction in which the long side is the transport direction). In addition, in the shift mode, it is possible to select and execute a productivity-priority mode that prioritizes productivity and an alignment-priority mode that prioritizes sheet alignment. Furthermore, in either shift mode, the sheet can be shifted in both directions: from the rear to the front and from the front to the rear (the shift direction is bidirectional).

[0079] The productivity-prioritizing mode, which is the switchbackless shift discharge process and the first shift discharge process, is a mode in which the sheet, which has been conveyed downstream in the first conveying direction by the pre-processing rollers 211A and 212A, is shifted in the shift direction by the matching section 270A (a pair of matching plates 271A) by driving the F-side matching plate moving motor MT16 and the R-side matching plate moving motor MT17, without conveying it in the second conveying direction by the scraping paddle 240A, and is discharged to the loading tray 300 by the upper discharge roller 230A and the lower discharge roller 230B.

[0080] The alignment priority mode, which is the switchback shift discharge process and the second shift discharge process, is a mode in which the sheet, which has been conveyed downstream in the first conveying direction by the pre-processing rollers 211A and 212A, is conveyed in the second conveying direction by the scraping paddle 240A on the processing tray 220, and after the downstream edge of the sheet in the second conveying direction is abutted against (restricted) the rear end restricting member 290, the sheet is shifted in the shift direction by the alignment section 270A (a pair of alignment plates 271A) by driving the F-side alignment plate moving motor MT16 and the R-side alignment plate moving motor MT17 without stapling by the staple unit 400, and then discharged to the loading tray 300 by the upper discharge roller 230A and the lower discharge roller 230B. A detailed explanation of this point will be given later.

[0081] When control is initiated, the control unit 203 determines whether the discharge mode is selected as straight discharge mode, shift mode, or staple mode (S1). If straight discharge mode is selected, the sheets sent to the sheet processing device 200A are discharged one by one into the loading tray 300 without any predetermined processing (S2).

[0082] In S1, if shift mode is selected, it is determined whether the sheet size is large or small (S3). If it is small, it is determined whether productivity is the priority (S4). If productivity is the priority, the sheet discharged from the transport path 210A is not transported in the second transport direction by the processing tray 220, but is shifted by the alignment unit 270A and discharged to the loading tray 300 (S5). If productivity is not the priority in S4, the sheet discharged from the transport path 210A is scooped into the processing tray 220, and the alignment unit 270A performs a shift operation on the processing tray 220 and discharges to the loading tray 300 (S6). If it is large in S3, the process proceeds to S6.

[0083] In S1, if the stapling mode is selected, the sheets discharged from the transport path 210A are transported in the second transport direction by the scraping paddle 240A on the processing tray 220, and the downstream edge of the sheet in the second transport direction is brought into contact with the rear end restricting member 290. That is, the rear end of the sheet is restricted. After restricting the rear end of the sheet, the F-side alignment plate moving motor MT16 and the R-side alignment plate moving motor MT17 are driven to position (align) the sheet to the stapling position by the alignment unit 270A (a pair of alignment plates 271A). This operation of restricting the rear end of the sheet and aligning it is repeated to form a sheet bundle on the processing tray 220 (S7). Then, the sheet bundle is stapled (S8). After that, the stapled sheet bundle is discharged to the loading tray 300 (S9).

[0084] The operation of the sheet processing device 200A in the first shift discharge process and the second shift discharge process in the shift mode described above will be explained using Figures 15(a) to 34(b).

[0085] [First Shift Discharge Processing (Productivity Priority Mode)] First, the first shift discharge process (productivity priority mode) among the shift modes will be explained using Figures 15(a) to 24(b). As shown in Figures 15(a) and (b), when the sheet S has not yet been conveyed to the transport path 210A, the upper discharge roller 230A, the scraping paddle 240A, and the rear end drop member 250A are all in their home positions. Also, the pair of alignment plates 271A are in their home positions, which are the positions furthest apart from each other.

[0086] Next, as shown in Figures 16(a) and (b), when the sheet S is transported to the entrance of the transport path 210A, the pair of alignment plates 271A move from their home positions toward each other and wait in the receiving position to receive the sheet. In this state as well, the upper discharge roller 230A, the scraping paddle 240A, and the rear end drop member 250A are all located in their home positions.

[0087] Next, as shown in Figures 17(a) and (b), when the downstream end (tip) of the sheet S in the first conveying direction passes the pre-processing nip portion 211a of the pre-processing rollers 211A and 212A, and the tip of the sheet S passes the lower discharge roller 230B, the upper discharge roller 230A begins to descend. For example, when the tip of the sheet S reaches a position 10 mm downstream from the nip position where the sheet is nipped by the upper discharge roller 230A and the lower discharge roller 230B, the upper discharge roller 230A is lowered so that the gap between the upper discharge roller 230A and the lower discharge roller 230B becomes 2 mm. That is, the retracted position. (1st separation position) The upper discharge roller 230A is closer to the lower discharge roller 230B than the upper discharge roller 230A and the lower discharge roller 230B are spaced apart from each other. (2nd separation position) They are positioned in this manner. At this time, the scraping paddle 240A and the rear end drop member 250A remain in their home positions.

[0088] Next, as shown in Figures 18(a) and (b), when the upstream end (rear end) of the sheet S in the first conveying direction passes the pre-processing nip section 211a of the pre-processing rollers 211A and 212A, the upper discharge roller 230A is lowered to the gripping position, and the sheet is nipped between the upper discharge roller 230A and the lower discharge roller 230B. At the same time, the rotation of the lower discharge roller 230B is stopped. For example, when the rear end of the sheet S reaches a position 10 mm downstream from the pre-processing nip section 211a, the upper discharge roller 230A is positioned in the gripping position. As a result, the sheet S is nipped between the upper discharge roller 230A and the lower discharge roller 230B, and conveying is stopped.

[0089] In this state, as shown in Figures 19(a) and (b), the upper discharge roller 230A is raised to a separated position, and the pair of alignment plates 271A are moved to a position in the width direction that matches the size of the sheet S. As a result, the sheet S is held between the plates from both sides in the width direction (both sides in the shift direction). Since the sheet S is held between the pair of alignment plates 271A, even if the upper discharge roller 230A is raised to a separated position, the sheet S is prevented from shifting in the first or second conveying direction.

[0090] Then, as shown in Figures 20(a) and (b), the sheet S is moved in the shift direction while being sandwiched between the pair of alignment plates 271A. That is, a shift operation is performed. After the shift operation is completed, as shown in Figures 21(a) and (b), the upper discharge roller 230A is lowered to the clamping position, and the sheet S is again nipped between the upper discharge roller 230A and the lower discharge roller 230B. Once the sheet S is nipped between the upper discharge roller 230A and the lower discharge roller 230B, the pair of alignment plates 271A are retracted from the sheet S, as shown in Figures 22(a) and (b). In this example, the shift direction is from the rear to the front, so the rear alignment plate of the pair of alignment plates 271A is designated as the first shift unit, and the front alignment plate is designated as the second shift unit. The rear alignment plate moving motor MT17 is designated as the first drive unit, and the front alignment plate moving motor MT16 is designated as the second drive unit. Conversely, if the shift direction is from the front to the rear, the front matching plate of the pair of matching plates 271A is designated as the first shift unit, and the rear matching plate is designated as the second shift unit. Furthermore, the front matching plate moving motor MT16 is designated as the first drive unit, and the rear matching plate moving motor MT17 is designated as the second drive unit.

[0091] Next, as shown in Figures 23(a) and (b), the lower discharge roller 230B is rotated to discharge the sheet S nipped by the upper discharge roller 230A and the lower discharge roller 230B into the loading tray 300. Once the sheet S is discharged into the loading tray 300, the rear end of the sheet S is pressed down by the sheet holding paddle 320A, as shown in Figures 24(a) and (b). At this time, the pair of alignment plates 271A move to the receiving position to receive the next sheet.

[0092] In this productivity-prioritizing mode, there is no operation to transport the sheet S in the second transport direction on the processing tray 220 (switchback transport), so the sheet S can be shifted faster than when the shifting operation is performed on the processing tray 220. While the productivity-prioritizing mode is preferably applicable to small-sized sheets, it may also be applied to large-sized sheets. In other words, it may be applied to all sheets that are shifted and discharged without stapling.

[0093] [Second shift discharge processing (alignment priority mode)] Next, the second shift discharge process (alignment priority mode) among the shift modes will be explained using Figures 25(a) to 34(b). Note that the alignment priority mode may be performed on small-sized sheets, but here we will explain the case where it is performed on large-sized sheets. The state in which the sheet S has not yet been transported to the transport path 210A, and the state in which the sheet S has been transported to the entrance of the transport path 210A, are the same as those shown in Figures 15(a) to 16(b) for the first shift discharge process.

[0094] In the second shift discharge process, as shown in Figures 25(a) and (b), even when the downstream end (tip) of the sheet S in the first conveying direction passes the pre-processing nip portion 211a of the pre-processing rollers 211A and 212A, and the tip of the sheet S passes the lower discharge roller 230B, the upper discharge roller 230A does not descend. That is, in this state, the upper discharge roller 230A, the scraping paddle 240A, and the rear end drop member 250A remain in their home positions.

[0095] Next, as shown in Figures 26(a) and (b), once the upstream end (rear end) of the sheet S in the first transport direction has passed the pre-processing nip portion 211a of the pre-processing rollers 211A and 212A, the scraping paddle 240A begins to descend. Then, as shown in Figures 27(a) and (b), the scraping paddle 240A is returned to its original position and the rear end dropping member 250A is lowered, causing the sheet S to fall onto the processing tray 220, and the scraping paddle 240A then transports the sheet S in the second transport direction.

[0096] Furthermore, as shown in Figures 28(a) and (b), the return member 280 (knurled belt 281) is also lowered, and the sheet S is transported in the second transport direction by the scraping paddle 240A and the return member 280, bringing the rear end of the sheet S into contact with the rear end regulating member 290. Then, as shown in Figures 29(a) and (b), the scraping paddle 240A, the rear end dropping member 250A and the return member 280 are raised. In this state, as shown in Figures 30(a) and (b), of the pair of alignment plates 271A, only the alignment plate 271A on the upstream side in the shift direction (upper side in Figure 30(a)) (first shift section) is moved toward the sheet S, and the sheet S is further moved in the shift direction by this alignment plate 271A. That is, in the second shift discharge process, the sheet S is shifted by moving the alignment plate 271A on the upstream side in the shift direction without clamping the sheet between the pair of alignment plates 271A. The matching plate 271A on the downstream side (lower side in Figure 30(a)) is initially in a receiving position when the shift operation begins, and moves from this receiving position in the shift direction according to the amount of shift of the seat S. Alternatively, the knurled belt 281 may be rotated and brought into contact with the upper surface of the seat during the shift operation by the matching plate 271A. This ensures that the rear end of the seat abuts against the rear end regulating member 290 during the shift operation, thus stabilizing the seat's behavior.

[0097] The reason the downstream alignment plate 271A is not moved from the receiving position to the sheet S side is to enable the shift operation in the second shift discharge process with multiple sheets placed on the processing tray 220. In other words, when performing a shift operation on the second and subsequent sheets, if the downstream alignment plate 271A is moved from the receiving position to the sheet side, the first sheet will also be pushed and moved by this downstream alignment plate 271A, which could disrupt the alignment of the first sheet.

[0098] Once the sheet S shift operation is complete, the upper discharge roller 230A is lowered to the gripping position, as shown in Figures 31(a) and (b), and the sheet S is nipped between the upper discharge roller 230A and the lower discharge roller 230B. After the sheet S is nipped between the upper discharge roller 230A and the lower discharge roller 230B, the pair of alignment plates 271A are retracted from the sheet S, as shown in Figures 32(a) and (b). This example describes the case where the second shift discharge process is performed on one sheet S, but when performing the second shift discharge process on two or more sheets, the upper discharge roller 230A is raised from this state, and the shift operation of the second and subsequent sheets is performed in the same way as the sheet S described above.

[0099] When discharging a sheet that has undergone a shift operation, with the upper discharge roller 230A in the gripping position, i.e., in the state shown in Figures 32(a) and (b), the lower discharge roller 230B is rotated as shown in Figures 33(a) and (b) to discharge the sheet S nipped between the upper discharge roller 230A and the lower discharge roller 230B into the loading tray 300. Once the sheet S has been discharged into the loading tray 300, the rear end of the sheet S is pressed down by the sheet holding paddle 320A as shown in Figures 34(a) and (b). At this time, the pair of alignment plates 271A move to the receiving position to receive the next sheet.

[0100] In this alignment-priority mode, the sheets S are aligned and shifted on the processing tray 220, resulting in better alignment of the sheets S than in the productivity-priority mode. However, in alignment-priority mode, the sheets are first placed on the processing tray 220, which takes longer than in productivity-priority mode. However, processing large-sized sheets also takes time within the image forming apparatus 100. Therefore, when executing alignment-priority mode for large-sized sheets, the shift operation can be performed at a productivity level suitable for the image forming apparatus 100, and the alignment of the sheets can be further improved. Note that even with large-sized sheets, the productivity-priority mode described above may be executed instead.

[0101] In this embodiment, when performing the staple mode, first shift discharge process, and second shift discharge process, the front-side matching plate moving motor MT16 and the rear-side matching plate moving motor MT17, which are common drive sources, and the common matching plate 271A are used to perform each process. Therefore, costs can be reduced compared to configurations that require separate matching plates or drive sources for each process.

[0102] In the above example, during the first and second shift discharge processes, the shift operation was performed with the upper discharge roller 230A separated from the lower discharge roller 230B. However, the shift operation may also be performed with a lower nip pressure between the upper discharge roller 230A and the lower discharge roller 230B. That is, in the above example, the drive configuration 600 for moving the upper discharge roller 230A functions as a discharge rotating body moving member that moves the upper discharge roller 230A between a clamping position, a separated position, and a retracted position. However, this drive configuration 600 may also function as a discharge rotating body nip pressure switching mechanism that switches the nip pressure used to clamp the sheet between the upper discharge roller 230A and the lower discharge roller 230B between a first nip pressure and a second nip pressure weaker than the first nip pressure. The shift operation may also be performed with the nip pressure set to the second nip pressure. The first nip pressure is the nip pressure when the sheet is discharged by the upper discharge roller 230A and the lower discharge roller 230B.

[0103] Furthermore, in the above example, in the first shift discharge process, the shift operation was performed after the sheet had passed the pre-processing nip portion 211a of the pre-processing rollers 211A and 212A. However, the shift operation may be performed while the sheet is still in the pre-processing nip portion 211a. Either the pre-processing rollers 211A and 212A may be made movable between a clamping position that holds the sheet and a separated position that separates them from each other, and the pre-processing rollers 211A and 212A may be moved to the separated position during the shift operation in the first shift discharge process. In addition, the nip pressure of the pre-processing rollers 211A and 212A may be made switchable between a first nip pressure and a second nip pressure weaker than the first nip pressure, and the second nip pressure may be used during the shift operation in the first shift discharge process. The mechanism for switching the nip pressure of the pre-processing rollers 211A and 212A and moving them between the clamping position and the separated position may be the same as in the second embodiment. Alternatively, for small-sized sheets, the shift operation by the pair of alignment plates 271A may be performed after the rear end of the sheet has passed the pre-processing nip section 211a, while for large-sized sheets, the shift operation by the pair of alignment plates 271A may be performed after the front end of the sheet has passed the discharge nip section 230a and before the rear end of the sheet has passed the pre-processing nip section 211a. This brings the portion of the large-sized sheet that contacts the pair of alignment plates 271A closer to the center of gravity of the sheet, thereby reducing the rotational force on the sheet during the shift operation.

[0104] Furthermore, in the above example, when the first shift discharge process is performed, the sheet S is shifted by moving the pair of alignment plates 271A in the shift direction while the sheet S is positioned between the upper discharge roller 230A and the lower discharge roller 230B, with the upper discharge roller 230A in a separated position (or in the second nip pressure state). Similarly, when the second shift discharge process is performed, the sheet S is shifted by moving the pair of alignment plates 271A in the shift direction while the sheet S is positioned between the upper discharge roller 230A and the lower discharge roller 230B, with the upper discharge roller 230A in a separated position (or in the second nip pressure state). Furthermore, when performing stapling mode, to align the sheet S on the processing tray 220 in the sheet width direction, the pair of alignment plates 271A are moved in the shift direction while the sheet S is positioned between the upper discharge roller 230A and the lower discharge roller 230B, with the upper discharge roller 230A in a separated position (or in the second nip pressure state) to align the sheet width direction.

[0105] In other words, when shifting the sheet S using a pair of matching plates 271A in the first shift discharge process, it is necessary to release the nip of the member that is nipping the sheet S (or change the nip pressure to the second nip pressure). However, the nip release mechanism (a mechanism that moves the upper discharge roller 230A between the clamping position and the separated position) is not provided exclusively for the first shift discharge process, but is also used for the second shift discharge process and the staple mode. Therefore, in the first embodiment described above, the nip release mechanism is common to all components compared to the second embodiment described later, and thus the staple mode, first shift discharge process, and second shift discharge process can be performed at a lower cost.

[0106] <Second Embodiment> A second embodiment will be described with reference to Figures 35 to 79. The image forming system 1000 of this embodiment has a similar schematic configuration to the image forming system 1000A of the first embodiment. That is, as shown in Figure 35, the image forming system 1000 of this embodiment includes an image forming apparatus 100, a punch unit 150, and a sheet processing apparatus 200. The configuration of the image forming apparatus 100 and the punch unit 150 is the same as in the first embodiment. However, the sheet processing apparatus 200 differs from the sheet processing apparatus 200A of the first embodiment in the following respects. The other configurations and operations are the same as in the first embodiment described above, so the sheet processing apparatus 200 of this embodiment will be described below.

[0107] [Sheet processing device] The configuration of the sheet processing apparatus 200 in this embodiment will be described using Figures 36 to 49. First, the overall configuration of the sheet processing apparatus 200 will be described using Figures 36 and 37(a) and (b).

[0108] [Overall configuration of the sheet processing device] The sheet processing device 200 includes a transport path 210, a processing tray 220 as a loading section, a discharge roller (nip member) 230, a scraping section 240 as a second transport section, a rear end dropping member 250 as a sheet dropping member, a discharge belt (bundle dispensing belt) 260, a alignment section 270 as a shift section, a return member 280, a rear end regulating member 290, a loading tray 300, a vertical surface 310, a sheet holding belt 320, and the like. The discharge roller 230 and the discharge belt 260 correspond to the discharge section and a pair of discharge rotating bodies. Sheets received from the image forming apparatus 100 or punch unit 150 are transported to the transport path 210.

[0109] The sheets transported from the transport path 210 are either directly discharged to the loading tray 300 or placed on the processing tray 220, depending on the mode of processing the sheets. Direct discharge to the loading tray 300 means that the sheets are discharged to the loading tray 300 without being transported back to a position on the processing tray 220 where stapling can be performed. In other words, the sheet processing device 200 has a mode in which sheets that have been stapled by the stapling unit 400 are discharged to the loading tray 300, and a mode in which sheets are discharged to the loading tray 300 without stapling by the stapling unit 400. In this embodiment, sheet alignment is made possible by the alignment unit 270 without placing the sheets on the processing tray 220. Sheet alignment is also possible on the processing tray 220, and stapling is made possible on sheets placed on the processing tray 220 by the stapling unit 400. Furthermore, the sheets or bundles of sheets placed on the processing tray 220 can be discharged to the loading tray 300 via the discharge belt 260 or the like. The configuration of each part will be described in detail below.

[0110] [Transport path] The transport path 210 is a path for transporting the sheet in a predetermined direction (first transport direction). The transport path 210 is equipped with a pre-processing roller 211 as a first rotating body, a transport belt 212 as a second rotating body, an upstream roller 213 as a third rotating body, and a knurled belt 214. These are each arranged in pairs so as to be spaced apart in the width direction of the sheet (arrow γ direction in Figure 37(a) (up and down direction)) that intersects the sheet transport direction (predetermined direction, arrow β direction in Figure 37(a) (left and right direction)).

[0111] The conveyor belt 212 is an endless belt positioned along the entire length of the conveyor path 210 in a predetermined direction to support the underside of the sheet received by the sheet processing device 200. The conveyor belt 212 is stretched over a pair of rollers 212a and 212b, and rotates when one of the rollers 212a is driven. An upstream roller 213 is positioned at the upstream end of the conveyor belt 212 in a predetermined direction, and the sheet is gripped (nipped) between the upstream roller 213 and the conveyor belt 212 at the entrance to the conveyor path 210 to convey the sheet.

[0112] A pre-processing roller 211 is positioned at the downstream end of the conveyor belt 212 in a predetermined direction, forming a pre-processing nip section 211a that can grip and convey the sheet between the pre-processing roller 211 and the conveyor belt 212. The pre-processing roller 211 and the conveyor belt 212 correspond to the first conveying section and a pair of conveying rotating bodies. The sheet is then gripped by the pre-processing nip section 211a and conveyed in a predetermined direction, and the sheet is discharged from the conveying path 210. In this embodiment, the pre-processing roller 211 and the conveyor belt 212 constitute a pair of conveying rotating bodies and a conveying means. As will be described later, the contact pressure (nip pressure) of the pre-processing roller 211 against the conveyor belt 212 can be changed.

[0113] The pre-processing roller 211 is rotationally driven in the same way as the conveyor belt 212, but since the conveyor belt 212 is rotationally driven, it may also be configured to rotate in accordance with the conveyor belt 212 without being rotationally driven itself. In this embodiment, the conveying path 210 is composed of multiple rollers and a conveyor belt, but the conveying path may also be configured by arranging multiple spheres above the conveyor belt so as to be rotatable in any direction. In this configuration, as will be described in detail later, it becomes possible to shift the sheet even when there is a sheet on the conveying path without adjusting the nip pressure, such as by reducing the nip pressure of the pre-processing roller 211.

[0114] The knurled belt 214 has its rotation axis coaxial with the downstream roller 212a that tensions the conveyor belt 212, and is rotatable together with the roller 212a. This knurled belt 214 is provided so as to protrude downstream of the downstream end of the conveyor belt 212 in a predetermined direction, making it less likely for the rear end (upstream end in a predetermined direction) of the sheet to remain on the pre-processing nip portion 211a when the sheet is discharged by the pre-processing roller 211 and the conveyor belt 212.

[0115] [Processing tray] The processing tray 220 is positioned downstream of the conveying path 210 in the sheet conveying direction and vertically below the conveying path 210. The processing tray 220 is also inclined with respect to the horizontal plane such that the upstream side in a predetermined direction is lower than the downstream side. The processing tray 220 can hold sheets conveyed from the conveying path 210, and can stack multiple sheets on top of each other. The alignment unit 270 on the processing tray 220 aligns the sheets in the width direction and moves them in the width direction (sheet shifting). Furthermore, a rear end regulating member 290, which is a regulating means and a processing-side regulating means, is positioned at the upstream end (rear end) of the sheet placed on the processing tray 220 in a predetermined direction.

[0116] Furthermore, a staple unit 400, which serves as a processing unit, is positioned upstream of the processing tray 220 in a predetermined direction. The staple unit 400 performs a stapling process, which is a predetermined process, on the sheet bundle that has been aligned in the width direction and restricted at the rear end by the processing tray 220. The staple unit 400 can change the staple position relative to the sheet bundle and moves according to the staple position. Note that the predetermined process may be other processes such as punching, in addition to stapling. The sheets or sheet bundles placed on the processing tray 220 are discharged to the loading tray 300 by the discharge roller 230, scraping section 240, and discharge belt 260, as will be described later.

[0117] [Ejection belt] The discharge belt 260 constitutes a pair of discharge rotating bodies and a discharge section that convey the sheet by clamping it between itself and the discharge roller 230. The discharge belt 260 is stretched by at least two tension rollers 261 and 262. That is, in this embodiment, the discharge belt 260 is stretched by two tension rollers 261 and 262, but there may be three or more tension rollers that stretch the discharge belt 260. Also, in this embodiment, three discharge belts 260 are arranged at positions spaced apart with respect to the width direction of the sheet. Of these three discharge belts 260, the central discharge belt 260 is positioned to clamp the sheet between itself and the scraping section 240, which will be described later, and the discharge belts 260 on both sides are positioned to clamp the sheet between themselves and the discharge rollers 230, respectively.

[0118] The discharge belt 260 is arranged along a predetermined direction and rotates when the tension roller 261 is rotationally driven, transporting the sheets or sheet bundles on the processing tray 220 toward the loading tray 300. In other words, the tension roller 261 is the drive roller that drives the discharge belt 260. Note that other rotating bodies such as discharge rollers may be used instead of the discharge belt, as long as they can transport the sheets or sheet bundles on the processing tray 220 toward the loading tray 300.

[0119] [Scooping area] The scraping section 240, which serves as the transfer means, processing-side transfer means, and dropping member, transfers the sheet placed on the processing tray 220 toward the rear end regulating member 290. The scraping section 240 is movable from a first position located vertically above the pre-processing nip section 211a, which nips the sheet with the pre-processing roller 211 and the conveyor belt 212, to a second position where it contacts the upper surface of the sheet placed on the processing tray 220 and can transfer the sheet toward the rear end regulating member 290.

[0120] At the second position, the scraping section 240 grips the sheet placed on the processing tray 220 between itself and the discharge belt 260. The position where the scraping section 240 grips the sheet between itself and the discharge belt 260 is upstream in a predetermined direction from the position where the discharge roller 230 (described later) grips the sheet between itself and the discharge belt 260. That is, at the second position, the scraping section 240 is located between the pre-processing roller 211 and the position where the sheet is nipped by the discharge roller 230 and the discharge belt 260 (discharge nip section) in a predetermined direction.

[0121] Such a scraping section 240 is rotationally driven in both forward and reverse directions, and as described above, it can transport the sheet on the processing tray 220 toward the rear end restricting member 290, that is, toward the upstream side in a predetermined direction, and together with the discharge belt 260, it can transport the sheet placed on the processing tray 220 toward the downstream side in a predetermined direction. That is, the scraping section 240 is equipped with a scraping belt 240a, as will be described later, and the scraping belt 240a can be rotationally driven in both forward and reverse directions. In the second position, it comes into contact with the sheet on the processing tray 220, and by rotating the scraping belt 240a in the forward direction in this state, the sheet is transported toward the rear end restricting member 290. On the other hand, by rotating the scraping belt 240a in the reverse direction, the sheet or sheet bundle on the processing tray 220 is transported toward the loading tray 300.

[0122] Sheets or bundles of sheets placed on the processing tray 220 are gripped by the discharge roller 230 and discharge belt 260 (described later) and discharged to the loading tray 300. However, conveyance by the discharge roller 230 and discharge belt 260 alone may not reliably discharge bundles of sheets. Conventionally, the discharge of bundles of sheets was assisted by moving the rear end restricting member 290 to the side from which the bundles of sheets were discharged. However, this embodiment does not employ such a configuration, and the rear end restricting member 290 does not move in the direction of discharging bundles of sheets. Therefore, in this embodiment, in order to assist in the discharge of bundles of sheets, the scraping section 240 is used to convey the bundles of sheets placed on the processing tray 220 toward the loading tray 300.

[0123] In particular, in this embodiment, the scraping section 240 is located between the pre-processing roller 211 and the discharge nip section in a predetermined direction at the second position, making it easier to transmit drive to the sheet on the processing tray 220. That is, the sheet on the processing tray 220 hangs down toward the loading tray 300 on the downstream side in a predetermined direction. Therefore, when the sheet is nipped at the discharge nip section, the downstream side of the discharge nip section hangs down, and the upstream side floats up. In this embodiment, by pressing the floating portion of the sheet on the processing tray 220 upstream of the discharge nip section against the scraping section 240, the drive of the scraping section 240 can be efficiently transmitted to the sheet, and sheet discharge can be efficiently assisted.

[0124] Furthermore, at the second position, the scraping section 240 grips the sheet or sheet bundle placed on the processing tray 220 between itself and the discharge belt 260. That is, the scraping section 240 presses against the upper surface of the sheet at a position facing the discharge belt 260 with the sheet or sheet bundle sandwiched between them. This increases the conveying force of the sheet or sheet bundle by the discharge belt 260. Moreover, by positioning the scraping section 240 to contact the sheet as close as possible to the discharge nip section, the scraping section 240 can provide assistance for a longer period of time.

[0125] The scraping section 240 includes a scraping belt 240a as a transfer belt, and at least two rollers 240b and 240c that tension the scraping belt 240a. That is, in this embodiment, the scraping belt 240a is tensioned by two rollers 240b and 240c, but there may be three or more rollers that tension the scraping belt 240a. In the second position, the tensioned surface of the scraping belt 240a, which is tensioned by the two rollers 240b and 240c, can contact the sheet placed on the processing tray 220. That is, the scraping section 240 can contact the sheet on the processing tray 220 with a wide contact area, thereby making it easier to transmit drive in the conveying direction to the sheet. In other words, by increasing and stabilizing the surface area in contact with the sheet, the conveying efficiency is improved and the contact pressure can be reduced. As a result, the occurrence of damage during sheet conveying can be reduced.

[0126] In this embodiment, the relationship between the contact positions of the scraping belt 240a and the discharge belt 260 is as shown in Figure 38(a). That is, at the second position, the scraping belt 240a is positioned to sandwich the sheet and the portion of the discharge belt 260 that is stretched between the two tension rollers 261 and 262. However, the relationship between the contact positions of the scraping belt 240a and the discharge belt 260 may be as shown in Figures 38(b) and (c).

[0127] That is, as shown in Figure 38(b), the scraping belt 240a may, at the second position, clamp the sheet between the tension roller 262 on the upstream side in a predetermined direction of the two tension rollers 261 and 262 and the discharge belt 260. Alternatively, as shown in Figure 38(c), at the second position, the portion of the scraping belt 240a stretched between the two rollers 240b and 240c may clamp the sheet between the tension roller 262 on the upstream side in a predetermined direction of the two tension rollers 261 and 262 and the discharge belt 260.

[0128] The scraping section 240 may be made of a rotating body other than a belt, such as a roller. For example, in the case of a roller, the roller may sandwich the sheet between the portion of the discharge belt 260 stretched over it and between two tension rollers 261 and 262, or the roller may sandwich the sheet between the tension roller 262 on the upstream side in a predetermined direction of the two tension rollers 261 and 262, via the discharge belt 260. However, in order to ensure a sufficient contact area with the sheet on the processing tray 220, it is preferable for the scraping section 240 to be made of a belt as in this embodiment.

[0129] Such a scraping section 240 is rotated around a pivot axis 242, which serves as the first pivot axis, between a first position and a second position by a scraping rotation mechanism 241, which serves as both a means of movement and a first means of rotation. In other words, the scraping section 240 is vertically movable between a first position and a second position. The scraping rotation mechanism 241 comprises a scraping arm 243, which serves as the first support member for supporting the scraping section 240, and a pivot axis 242 that rotatably supports the scraping arm 243, so that the scraping section 240, supported at the tip of the scraping arm 243, is rotatable around the pivot axis 242.

[0130] Here, it is preferable that the scraping section 240 moves along the vertical direction, and it is conceivable that the mechanism for moving the scraping section 240 between the first and second positions be a linear motion mechanism. However, if a linear motion mechanism is adopted, there is a risk that the device will become larger in the vertical direction, for example, by arranging a motor or a shaft for linear motion in the vertical direction. As described above, since the sheet processing apparatus 200 of this embodiment is arranged in the internal space 130 of the cylinder of the image forming apparatus 100, it is undesirable for the dimensions in the vertical direction to be large. Therefore, in this embodiment, a scraping rotation mechanism 241 is adopted that rotates the scraping section 240 around a pivot axis 242. Note that if the sheet processing apparatus can secure vertical dimensions, a linear motion mechanism may be adopted as the mechanism for raising and lowering the scraping section 240. Furthermore, by making the distance between the pivot axis 242 and the scraping section 240 as large as possible and increasing the rotation radius, the scraping section 240 can be moved as much as possible along the vertical direction.

[0131] The pivot shaft 242 is positioned downstream in a predetermined direction from the discharge nip section where the discharge roller 230 nips the sheet between itself and the discharge belt 260 at the contact position. This allows for a larger rotation trajectory (radius of rotation) of the scraping section 240, enabling movement closer to linear motion. Furthermore, at the first position, the scraping section 240 is positioned vertically above the pre-processing nip section 211a where the sheet is nipped between the pre-processing roller 211 and the conveyor belt 212, and the pivot shaft 242 is positioned vertically above the scraping section 240 at the first position.

[0132] As will be described later, the pivot axis 232 of the discharge roller 230 is positioned upstream of the discharge nip section in a predetermined direction, and the direction of rotation is preferably counterclockwise as shown in Figure 37(b) in relation to the sheet being conveyed from the pre-processing nip section 211a. On the other hand, the pivot axis 242 of the scraping section 240 is required to have a large radius of rotation as described above, and the second position is preferably upstream of the discharge nip section in a predetermined direction. From this viewpoint, in this embodiment, the pivot axis 242 is positioned downstream of the discharge nip section in a predetermined direction, and the direction of rotation of the scraping section 240 is set to the opposite side of the rotation direction of the discharge roller 230, that is, in the direction of arrow R1 (clockwise) in Figure 37(b). Furthermore, the rotational trajectories of each are set to overlap when viewed from the width direction.

[0133] In other words, the rotational trajectory of the scraping arm 243 supporting the scraping section 240 is on the side of the rotation axis 232 of the discharge roller 230 (the second rotation axis side) rather than the rotation axis 242. On the other hand, the rotational trajectory of the discharge arm 233 supporting the discharge roller 230, which will be described later, is on the side of the rotation axis 242 of the scraping section 240 (the first rotation axis side) rather than the rotation axis 232. Furthermore, the rotational trajectory of the scraping arm 243 overlaps with a portion of the rotational trajectory of the discharge arm 233 when viewed from the width direction of the sheet, which intersects the sheet conveying direction. For this reason, in this embodiment, the discharge roller 230 and the scraping section 240 are positioned at offset positions with respect to the width direction. Specifically, two discharge rollers 230 are placed on both sides in the width direction, and one scraping section 240 is placed between the two discharge rollers 230. This configuration allows for a larger rotation radius of the scraping section 240, and also enables the scraping section 240 to contact the sheet on the processing tray 220 upstream of the discharge nip section in a predetermined direction.

[0134] In this embodiment, as described above, in order to increase the rotation radius of the scraping section 240, the pivot shaft 242 is positioned above the discharge port 201 of the sheet processing device 200 shown in Figure 35. The discharge port 201 of the sheet processing device 200 is provided with a canopy 202 to prevent fingers or other objects from entering the staple unit 400. In particular, in this embodiment, the length of the processing tray 220 has been shortened to reduce costs, making it easy for fingers or other objects to reach the staple unit 400, but the canopy 202 prevents fingers or other objects from reaching the staple unit 400 from the discharge port 201. If such a canopy 202 were not provided, it would be necessary to install a safety switch that detects the intrusion of fingers or other objects and automatically stops the operation of the staple unit 400, which would increase costs.

[0135] For these reasons, a canopy portion 202 is provided above the discharge port 201. In this embodiment, by providing this canopy portion 202, it is possible to position the pivot axis 242 of the scraping portion 240 near the discharge port 201. This allows the pivot axis 242 to be separated from the scraping portion 240, which moves above the processing tray 220, thereby increasing the rotation radius of the scraping portion 240 and making the direction of movement of the scraping portion 240 as linear as possible.

[0136] The reason for moving the scraping section 240 in a direction as linear as possible is to minimize the change in the angle of the tensioned surface of the scraping belt 240a when the scraping section 240 is in the first and second positions. Specifically, in the second position, in order to secure the contact area between the scraping belt 240a and the sheet, the tensioned surface of the scraping belt 240a is configured to be approximately parallel to the sheet mounting surface of the processing tray 220 or the upper surface of the sheet on the processing tray 220. Approximately parallel means, for example, that the angle of the tensioned surface with respect to the upper surface of the sheet is within ±5°. If the rotation radius of the scraping section 240 is small, when the scraping section 240 is moved to the first position, the tensioned surface of the scraping belt 240a will rise, and the vertical dimension of the scraping section 240 in the first position will increase. This would then require the device to be larger in order to secure the space for this dimension. Therefore, in this embodiment, the rotation radius of the scraping portion 240 is increased.

[0137] Furthermore, as the number of sheets placed on the processing tray 220 increases, the position at which the scraping belt 240a contacts the sheets rises. Therefore, in the case of a mechanism in which the angle of the tensioned surface of the scraping belt 240a does not change, the contact area between the scraping belt 240a and the sheets will change depending on the amount of sheets loaded. For this reason, a mechanism that allows the angle of the scraping belt 240a to be changed may be added. For example, as shown in Figures 39(a) and (b), the rollers 240b and 240c that tension the scraping belt 240a are connected by an arm 240d, and a pivot axis 240e is provided on the roller 240c on the upstream side in a predetermined direction, so that the scraping belt 240a can rotate around the pivot axis 240e relative to the scraping arm 243. Then, by providing a compression spring or torsion spring so that the roller 240b on the downstream side in a predetermined direction is biased toward the sheet, the angle of the tensioned surface of the scraping belt 240a changes in accordance with the surface of the sheet. As a result, regardless of the amount of sheets loaded on the processing tray 220, the tensioned surface of the scraping belt 240a can contact the upper surface of the sheet with a wide contact area.

[0138] Furthermore, in this embodiment, the scraping section 240 also functions as a dropping member that drops the rear end (upstream end in a predetermined direction) of the sheet being conveyed from the pre-processing roller 211 toward the processing tray 220. That is, the scraping rotation mechanism 241 positions the scraping section 240 in a first position when the sheet is being conveyed by the pre-processing roller 211 and the conveyor belt 212. On the other hand, after the upstream end (rear end) of the sheet in a predetermined direction has passed the pre-processing nip section 211a of the pre-processing roller 211 and the conveyor belt 212, the scraping rotation mechanism 241 moves the scraping section 240 from the first position to a second position, dropping the sheet toward the processing tray 220. This prevents the rear end of the sheet from remaining on the pre-processing nip section 211a. Furthermore, the timing for the start of movement of the scraping section 240 from the first position to the second position may be before the upstream end in the sheet transport direction passes the pre-processing nip section 211a, and it is sufficient if the movement to the second position is completed after the upstream end in the sheet transport direction has passed the pre-processing nip section 211a, so that the sheet can be dropped into the processing tray 220. The same applies to the movement timing of the rear end dropping member 250, which will be described later.

[0139] In particular, in this embodiment, the scraping section 240 is positioned in a first position when the sheet is being conveyed by the pre-processing roller 211 and the conveyor belt 212. That is, the scraping section 240 is waiting above the pre-processing nip section 211a. Therefore, it is easier to bring the scraping section 240 into contact with the upper surface of the rear end of the sheet that has passed through the pre-processing nip section 211a and to push it further downward, thereby more reliably dropping the rear end of the sheet into the processing tray 220. Furthermore, the scraping section 240, which also functions when dropping the rear end of the sheet, has a scraping belt 240a stretched by two rollers 240b and 240c as described above. In this embodiment, when dropping the rear end of the sheet, the stretched surface of the scraping belt 240a is brought into contact with the upper surface of the sheet. Therefore, for example, a larger contact area with the sheet can be secured compared to when the scraping section is a roller, and the rear end of the sheet can be dropped more reliably.

[0140] [Rear end drop member] The aforementioned scraping section 240 is located in the center of the sheet in the width direction, and there is a possibility that the rear end of the sheet may not be sufficiently dropped by the scraping section 240 alone. For this reason, this embodiment further includes a rear end dropping member 250 as an upstream end dropping member. A pair of rear end dropping members 250 are provided on both sides of the scraping section 240. That is, the pair of rear end dropping members 250 are arranged on both sides of the scraping section 240 with respect to the width direction of the sheet intersecting the sheet transport direction, and move vertically in conjunction with the scraping section 240, so that after the upstream end of the sheet in a predetermined direction has passed the pre-processing nip section 211a, they come into contact with the upper surface of the upstream side (upstream side in the sheet transport direction) of the sheet, and drop the upstream end (rear end) of the sheet toward the processing tray 220.

[0141] Each of these rear end drop members 250 is a plate-shaped member and, like the scraping section 240, is rotatably supported on the pivot shaft 242. They rotate vertically together with the scraping section 240 by the scraping rotation mechanism 241. When the scraping section 240 is in the first position, the tips of the pair of rear end drop members 250 are positioned above the pre-processing nip section 211a, similar to the scraping section 240. When the scraping section 240 is in the second position, the surfaces of the pair of rear end drop members 250 that contact the sheet (the lower surfaces of the tips) are positioned above the surface of the scraping section 240 that contacts the sheet. The lower surfaces of the tips of the rear end drop members 250 contact the upper surface of the curled portion of the sheet placed on the processing tray 220 if the sheet is curled, and the upper surface of the lifted portion if the rear end of the sheet bundle is lifted when the sheet bundle is discharged. Furthermore, if the rear end drop member 250 is positioned in the second position so as to face the discharge belt 260 with the sheet or sheet bundle in between, it may be positioned to contact the upper surface of the sheet or sheet bundle placed on the processing tray 220, similar to the scraping section 240. In this way, when the rear end drop member 250 is positioned to sandwich the sheet between itself and the discharge belt 260, the upper surface of the sheet or sheet bundle is pressed against the scraping section 240 on both sides in the width direction at the second position, thereby more reliably pressing the sheet or sheet bundle toward the discharge belt 260 and more reliably transporting the sheet or sheet bundle. The tips of the pair of rear end drop members 250 are bent sections 251 that are folded so as to be substantially parallel to the upper surface of the sheet on the processing tray 220 at the second position. The rotational trajectory of the pair of rear end drop members 250 is the same as that of the scraping section 240 and the scraping arm 243.

[0142] [Return component] The return member 280 further transports the sheet, which has been conveyed toward the rear end restricting member 290 by the scraping section 240 as described above, toward the rear end restricting member 290, and restricts the position of the rear end of the sheet by bringing the rear end of the sheet into contact with the rear end restricting member 290. Such a return member 280 is made up of a knurled belt 281, and by rotating the knurled belt 281, it further scrapes the sheet that has been conveyed toward the upstream side in a predetermined direction by the scraping section 240, bringing the rear end into contact with the rear end restricting member 290. The return member 280 is movable between a contact position where it can contact the sheet and a retracted position which is moved upward from the contact position. As will be described in more detail later, it moves to the contact position when conveying the sheet toward the rear end restricting member 290, and to the retracted position when conveying the sheet on the processing tray 220 toward the loading tray 300.

[0143] [Discharge roller] The discharge roller 230, together with the discharge belt 260, constitutes a pair of discharge rotating bodies and a discharge section. The discharge roller 230, as the upper discharge rotating body, is movable between a contact position in contact with the upper surface of the sheet placed on the processing tray 220 and a retracted position moved upward from the contact position, and at the contact position it grips the sheet between itself and the discharge belt 260. In other words, the discharge roller 230 functions as a nipping member that nips the sheet between itself and the discharge belt 260 at the contact position. Two discharge rollers 230 are arranged spaced apart in the width direction of the sheet, and as described above, each discharge roller 230 is capable of gripping the sheet between itself and the corresponding discharge belt 260 at the contact position.

[0144] Furthermore, in this embodiment, two discharge rollers 230 are arranged spaced apart in the width direction. That is, one discharge roller 230 is positioned between one of the pair of rear end drop members 250 and the scraping section 240, and another between the other rear end drop member 250 and the scraping section 240. These two discharge rollers 230 grip the sheets or sheet bundles with the discharge belts 260 on both sides in the width direction at the contact point. Then, as the discharge belts 260 rotate, the sheets or sheet bundles gripped by the discharge rollers 230 and the discharge belts 260 are conveyed. By gripping and conveying the sheets or sheet bundles with the discharge rollers 230 and the discharge belts 260 at positions spaced apart in the width direction in this way, skew is less likely to occur when conveying the sheets or sheet bundles. Furthermore, in this process, the sheet or sheet bundle is held between the discharge belt 260 and the scraping section 240 in the center of the width direction, assisting in the discharge of the sheet or sheet bundle. As a result, the conveying force can be transmitted to the sheet at three points in the width direction when the sheet or sheet bundle is discharged, allowing for more reliable discharge of the sheet or sheet bundle while suppressing skew.

[0145] The discharge roller 230 is a driven roller that rotates in accordance with the rotation of the discharge belt 260, but it may also be driven. That is, in this embodiment, the discharge roller 230 is the driven rotating body, and the discharge belt 260 is the driving rotation. Furthermore, the discharge roller 230 functions as a nip member that can clamp the sheet between itself and the discharge belt 260 at the contact position, but this nip member may be another rotating body such as a belt instead of a roller, or it may be a contact member that contacts the sheet without rotating, such as a lever member.

[0146] At the contact point, the discharge roller 230 is positioned to face the downstream tension roller 261 of the tension rollers 261 and 252 that tension the discharge belt 260, via the discharge belt 260. This allows the sheet to be gripped between the discharge roller 230 and the tension roller 261 via the discharge belt 260 at the contact point, ensuring more secure gripping and transport of the sheet.

[0147] The discharge roller 230 is rotatable from a contact position to a retracted position around a pivot shaft 232, which serves as a second pivot axis, by a discharge roller rotation mechanism 231, which serves as a second pivoting means. In other words, the discharge roller 230 is vertically adjustable from the contact position to the retracted position. The discharge roller rotation mechanism 231 comprises a discharge arm 233, which serves as a second support member supporting the discharge roller 230, and a pivot shaft 232, which rotatably supports the discharge arm 233. The discharge roller 230, supported at the tip of the discharge arm 233, is rotatable around the pivot shaft 232. The detailed configuration of the discharge roller rotation mechanism 231 will be described later.

[0148] The pivot shaft 232 is positioned upstream in a predetermined direction from the discharge nip section where the discharge roller 230 nips the sheet between itself and the discharge belt 260 at the contact position. Furthermore, the discharge roller 230 is positioned vertically above the pre-processing nip section 211a where the sheet is nipped between the pre-processing roller 211 and the conveyor belt 212 at the retracted position, and the pivot shaft 232 is positioned vertically above the discharge roller 230 at the retracted position.

[0149] Since the positional relationship between the discharge roller 230 and the pivot axis 232 and the pre-processing nip portion 211a is defined as described above, when it is in the retracted position, it allows the sheet that has passed through the pre-processing nip portion 211a to move toward the loading tray 300. On the other hand, the discharge roller 230 rotates around the pivot axis 232 in the direction of arrow R2 (counterclockwise) in Figure 37(b), moving downward from the retracted position toward the contact position. At this time, the discharge arm 233 enters the path through which the sheet that has passed through the pre-processing nip portion 211a travels, and also plays the role of guiding the sheet downward. Specifically, when the sheet that has passed through the pre-processing nip portion 211a is guided by the discharge arm 233, the discharge roller 230 stops at a guide position, which is a position between the contact position and the retracted position in the vertical direction. Then, as the discharge roller 230 moves further downward from the guide position to the contact position, the sheet can be clamped between the discharge roller 230 and the discharge belt 260.

[0150] [Matching part] The alignment unit 270, which serves as both an alignment means and a shift unit, has a pair of alignment plates 271, which serve as a first shift unit and a second shift unit. The pair of alignment plates 271 are positioned further downstream than the downstream end (the predetermined downstream end) in the sheet transport direction of the transport path 210, and move in the width direction of the sheet intersecting the sheet transport direction to contact the widthwise edge of the sheet, thereby aligning the sheet in the width direction. In this embodiment, they are positioned on both sides in the width direction of the sheet placed on the processing tray 220, and are movable in the width direction. The configuration of the pair of alignment plates 271 is the same. The pair of alignment plates 271 move in the shift direction by the drive of the front (F side) alignment plate moving motor MT5 and the rear (R side) alignment plate moving motor MT6 (see Figure 49), which serve as the first and second drive units.

[0151] Furthermore, the pair of matching plates 271 have a first contact portion 272 and a second contact portion 273. The first contact portion 272 is located further downstream than the downstream end of the conveying path 210 in the sheet conveying direction, and is capable of contacting the widthwise edge of the sheet that hangs down from the conveying path 210 towards the processing tray 220. That is, the first contact portion 272 is positioned so as to be able to contact the widthwise edge of the sheet when the leading edge (downstream end in a predetermined direction) of the sheet being conveyed on the conveying path 210 has passed the pre-processing nip portion 211a, but the rear end has not passed the pre-processing nip portion 211a, and the first contact portion 272 hangs down from the conveying path 210 towards the pre-processing nip portion 211a. In this embodiment, the first contact portion 272 is shown to be located further downstream than the downstream end of the conveying path 210 in the sheet conveying direction. However, the first contact portion 272 may be extended not only further downstream than the downstream end of the conveying path 210 in the sheet conveying direction, but also upstream of the pre-processing nip portion 211a in the sheet conveying direction, so as to contact the edge in the sheet width direction while straddling the pre-processing nip portion 211a.

[0152] The second contact portion 273 is positioned below the first contact portion 272 and extends downstream of the first contact portion 272 in the sheet transport direction, and is capable of contacting the widthwise edge of the sheet when the sheet placed on the processing tray 220 has a downstream end in the sheet transport direction that protrudes further toward the loading tray 300 side (loading tray side) than the downstream end of the processing tray 220 in the sheet transport direction. In other words, the second contact portion 273 is provided in a position that can contact the widthwise edge of the sheet when it is placed on the processing tray 220. The processing tray 220 is usually shorter than the sheet placed on it, and even if the rear end of the sheet is restricted as described above when placed on the processing tray 220, the leading edge of the sheet will hang down toward the loading tray 300 side. The second contact portion 273 is formed in a position that can contact the widthwise edge of the sheet in this state.

[0153] Furthermore, as will be described in more detail later, the second contact portion 273 can also contact the widthwise edge of the sheet hanging down from the transport path 210 towards the processing tray 220, together with the first contact portion 272. As described above, the discharge roller 230 rotates from the retracted position to the guide position. As will be described in more detail later, the discharge roller 230 and the discharge arm 233 start rotating toward the guide position in time with the sheet being discharged from the transport path 210, and also serve as guide means to contact the leading edge or top surface of the sheet as it is being discharged from the transport path 210, guiding the sheet downwards. As the sheet is guided downwards by the discharge roller 230 and the discharge arm 233 in this way, the widthwise edge of the sheet comes into contact with the first contact portion 272 and the second contact portion 273.

[0154] Here, the first contact portion 272 is located vertically above the second contact portion 273. The pair of alignment plates 271 also have a notch 274 cut out so as not to interfere with the rear end drop member 250 described above. That is, the pair of alignment plates 271 have a second contact portion 273 that is long in a predetermined direction, a first contact portion 272 formed to extend upward from the upstream portion of the second contact portion 273 in a predetermined direction, and a notch 274 formed above the downstream portion of the second contact portion 273 in a predetermined direction. As described above, since the rear end drop member 250 rotates around a pivot axis 242 downstream of the discharge nip portion in a predetermined direction, the downstream portion of the pair of alignment plates 271 in a predetermined direction is notched out to prevent interference with the rear end drop member 250.

[0155] On the other hand, as described above, the first contact portion 272 is provided above the upstream portion in a predetermined direction of the second contact portion 273 so that it can come into contact with the widthwise edge of the sheet hanging down from the transport path 210. Furthermore, the second contact portion 273 is formed to also exist below the notch portion 274 so that the widthwise edge of the sheet hanging down from the transport path 210 can come into contact with the second contact portion 273.

[0156] As will be explained in more detail later, when the sheet hangs down from the transport path 210 and is brought into contact with the widthwise edge of the sheet, the nip pressure of the pre-processing roller 211 is set to almost zero, and even when the sheet is on the transport path 210, the pair of alignment plates 271 enable alignment of the sheet or movement (shifting) of the sheet in the widthwise direction. Furthermore, as described above, the second contact portion 273 comes into contact with the widthwise edge of the sheet hanging down from the transport path 210 together with the first contact portion 272, enabling alignment of the sheet or movement of the sheet in the widthwise direction. In addition, the second contact portion 273 is movable in the widthwise direction along the sheet-mounting surface of the processing tray 220 so that it can come into contact with the widthwise edge of the sheet placed on the processing tray 220, and is formed to be longer than the first contact portion 272 in a predetermined direction, so that the contact area with the widthwise edge of the sheet on the processing tray 220 is increased.

[0157] [Loading tray] As described above, the loading tray 300 is used to load the sheets discharged by the discharge roller 230 and the discharge belt 260. The loading tray 300 is located downstream of the processing tray 220 in a predetermined direction and is capable of moving up and down vertically. Furthermore, the loading tray 300 is inclined with respect to the horizontal plane such that the upstream side in a predetermined direction is lower than the downstream side. Such a loading tray 300 is supported, for example, so as to be movable vertically along rails arranged in the vertical direction, and moves up and down by driving a lifting motor MT9 (Figure 48) as a means of lifting and lowering.

[0158] At the upstream end of the loading tray 300 in a predetermined direction, there is a vertical surface 310 which serves as a loading-side restricting means to restrict the upstream end (rear end) of the sheet or sheet bundle loaded on the loading tray 300 in a predetermined direction. At the downstream end of the processing tray 220 in a predetermined direction, there is a sheet retaining belt 320 which is an endless belt and at least a portion of it is provided to protrude downstream of the vertical surface 310 in a predetermined direction and below the sheet mounting surface of the processing tray 220. The sheet retaining belt 320 is a knurled belt similar to the return member 280 described above.

[0159] The loading tray 300 can be raised and lowered by the lifting motor MT9 between a first loading position and a second loading position which is lower than the first loading position. The first loading position is the position where the sheet on the loading tray can come into contact with the sheet holding belt 320. The second loading position is the position where the operation of the loading tray 300, which was descending when discharging a sheet onto the loading tray 300, switches to an upward movement.

[0160] As will be explained in more detail later, the loading tray 300 moves up and down when a sheet or sheet bundle is discharged, and the upper surface of the rear end of the sheet or sheet bundle on the loading tray 300 comes into contact with the sheet retaining belt 320. As a result, the rear end of the sheet or sheet bundle on the loading tray 300 is held down by the sheet retaining belt 320, and even if the sheet or sheet bundle is discharged afterward, it is possible to prevent the sheet or sheet bundle already loaded on the loading tray 300 from shifting.

[0161] In addition to its function of holding down the rear end of a sheet or sheet bundle on the loading tray 300, the sheet holding belt 320 is also rotationally driven to transport the sheet or sheet bundle on the loading tray 300 toward the vertical surface 310, and aligns the rear end of the sheet or sheet bundle by abutting it against the vertical surface 310. This sheet holding belt 320 is arranged coaxially with the tension roller 261 that drives the discharge belt 260, which acts as a driving rotating body. That is, a roller that drives the sheet holding belt 320 is also provided on the drive shaft 261a of the tension roller 261, and the discharge belt 260 and the sheet holding belt 320 rotate synchronously.

[0162] [Drive configuration of sheet processing device] Next, the drive configuration 500 for each part of the sheet processing device 200 will be explained using Figures 40 to 48. Figure 40 shows the configuration of the drive configuration 500 for varying the nip pressure of the pre-processing roller 211, driving the conveyor belt 212, and raising and lowering the discharge roller 230. The conveyor motor MT1 transmits power to the drive shaft 502 of the roller 212a that drives the conveyor belt 212 via the transmission belt 501. Since a roller that drives the knurled belt 214 is also provided on the drive shaft 502, the knurled belt 214 is also rotationally driven by the conveyor motor MT1.

[0163] Furthermore, the drive of the transport motor MT1 is transmitted to the pre-processing roller 211 and the return member 280 via a transmission mechanism (not shown). Therefore, the transport motor MT1 synchronously rotates the pre-processing roller 211, the transport belt 212, the knurled belt 214, and the return member 280.

[0164] The lifting motor MT3 is connected to the pivot shaft 232 of the discharge roller 230, and when the lifting motor MT3 is driven, the discharge roller 230 moves up and down from the contact position to the retracted position as described above. In this embodiment, the nip pressure of the pre-processing roller 211 can also be changed by driving the lifting motor MT3. That is, the lifting motor MT3 also functions as a nip pressure adjustment means (conveyor rotating body nip pressure switching mechanism) that can adjust the nip pressure that grips the sheet between the pre-processing roller 211 as the first rotating body and the conveyor belt 212 as the second rotating body. The pre-processing roller 211 and the conveyor belt 212 correspond to the first conveying section and the pair of conveyor rotating bodies that convey the sheet in the first conveying direction (predetermined direction).

[0165] Figures 41(a) and (b) show this configuration. The pre-processing roller 211 is held by the roller holding part 511, which is movable in the vertical direction, that is, it is movable in a direction toward or toward the portion of the conveyor belt 212 that is stretched over the roller 212a. The roller holding part 511 is biased by a torsion spring 512, which acts as a biasing means, in a direction that presses the pre-processing roller 211 against the conveyor belt 212. The torsion spring 512 is also supported by the pivot shaft 232 of the discharge roller 230 and rotates together with the pivot shaft 232.

[0166] Specifically, one end of the torsion spring 512 is in contact with the roller holding portion 511, and a portion of the other end of the torsion spring 512, straddling the pivot shaft 232, is in contact with a projection 233a provided on the discharge arm 233 that supports the discharge roller 230. As a result, the torsion spring 512 is positioned in a state of elastic tension between the roller holding portion 511 and the projection 233a. When the discharge arm 233 rotates together with the pivot shaft 232, the position of the portion of the other end of the torsion spring 512 that is in contact with the projection 233a changes, and the torsion spring 512 rotates together with the pivot shaft 232 around the pivot shaft 232. This changes the force biasing the roller holding portion 511 by the torsion spring 512, and the nip pressure on the pre-processing roller 211 can be changed.

[0167] Figure 41(a) shows the discharge roller 230 in the retracted position. In this state, the roller holder 511 is biased by the torsion spring 512, and the pre-processing roller 211 is in contact with the conveyor belt 212 with a predetermined nip pressure (first pressure). On the other hand, Figure 41(b) shows the discharge roller 230 descending toward the contact position. When the pivot shaft 232 rotates in the direction that lowers the discharge roller 230 toward the contact position due to the drive of the lifting motor MT3, the torsion spring 512 also rotates along with it. As a result, the biasing of the roller holder 511 by the torsion spring 512 is released, and the nip pressure of the pre-processing roller 211 toward the conveyor belt 212 becomes approximately 0 (a second pressure smaller than the first pressure). In other words, the pre-processing roller 211 is in contact with the conveyor belt 212 due to its own weight.

[0168] In this embodiment, the nip pressure of the pre-processing roller 211 against the conveyor belt 212 can be changed by driving the lifting motor MT3 to raise and lower the discharge roller 230. Therefore, as will be described later, when the alignment operation by the alignment unit 270 is performed with a portion of the sheet remaining on the conveyor path 210, the nip pressure of the pre-processing roller 211 can be reduced to almost zero by lowering the discharge roller 230. If the nip pressure of the pre-processing roller 211 is almost zero, the sheet can be moved in the width direction even if it is pinched between the pre-processing roller 211 and the conveyor belt 212.

[0169] As shown in Figure 40, a flag 513 is provided at the end of the pivot shaft 232, and this flag 513 can be detected by the nip member HP position detection sensor SN2. The nip member HP position detection sensor SN2 is a photointerrupter equipped with a light-emitting unit and a light-receiving unit, and when the flag 513 is positioned between the light-emitting unit and the light-receiving unit, it detects that the discharge roller (nip member) 230 is in a retracted position, i.e., the home position.

[0170] As shown in Figure 42, the lifting motor MT3 is connected to the pivot shaft 242 of the scraping section 240 and the rear end drop member 250 via a transmission belt 514 and an electromagnetic clutch CL1. Specifically, the transmission belt 514 is stretched between a pulley 515 provided on the pivot shaft 232 of the discharge roller 230 and a pulley 516 driven and connected to the electromagnetic clutch CL1 by a gear or the like. The electromagnetic clutch CL1 is connected to the pivot shaft 242. As shown in Figures 43 and 44(a), the connection between the electromagnetic clutch CL1 and the pivot shaft 242 is made by the engagement of a lifting lever 517 provided on the electromagnetic clutch CL1 and a projection 518 protruding from the pivot shaft 242.

[0171] In other words, the lifting lever 517 is fixed to the output shaft of the electromagnetic clutch CL1, and as the output shaft rotates, it swings around the pivot center of the pivot shaft 242. The projection 518 is located below the lifting lever 517 and is positioned to engage with the lifting lever 517. Therefore, when the lifting lever 517 swings, it engages with the projection 518, and the pivot shaft 242 on which the projection 518 is located rotates. In this embodiment, as will be described later, the scraping arm 243 and the rear end drop member 250 are biased upward by the tension spring 252, so the projection 518 is also biased to abut against the lifting lever 517 which is located above it. Therefore, when the electromagnetic clutch CL1 is ON and the lifting motor MT3 is driven in the forward direction, the scraping part 240 and the rear end drop member 250 move downward due to the engagement between the lifting lever 517 and the projection 518. On the other hand, when the lifting motor MT3 is driven in the reverse direction, the lifting lever 517 swings upward, and the projection 518 follows the lifting lever 517 and moves upward due to the tension spring 252. In other words, by driving the lifting motor MT3 in the reverse direction, the scraping section 240 and the rear end drop member 250 can be moved upward.

[0172] In summary, when the electromagnetic clutch CL1 is ON, the drive from the pulley 516 is connected to the pivot shaft 242, causing the pivot shaft 242 to rotate due to the drive of the lifting motor MT3, and the scraping section 240 and the rear end dropping member 250 to move up and down. On the other hand, when the electromagnetic clutch CL1 is OFF, the drive transmission between the pulley 516 and the pivot shaft 242 is disconnected, so even if the lifting motor MT3 is driven, the pivot shaft 242 does not rotate, and in this case, only the discharge roller 230 moves up and down.

[0173] Furthermore, a tension spring 252 is provided on the rear end drop member 250. One end of the tension spring 252 is connected to the front end of the rear end drop member 250, and the other end is connected to a frame on the upper surface of the device (not shown), biasing the rear end drop member 250 upward, i.e., toward the first position. Therefore, the rear end drop member 250 is biased upward.

[0174] Here, as shown in Figure 43, the pivot shaft 242 is positioned around the drive shaft 244 for driving the scraping belt 240a, which will be described later, so as to be rotatable relative to the drive shaft 244. The drive shaft 244 is not connected to the electromagnetic clutch CL1, and the pivot shaft 242 can rotate independently of the drive shaft 244. The pivot shaft 242 has a first part 242a to which the base end (supported part; not necessarily the end of the member, and there may be a part that protrudes on the opposite side of the member from the front end of the member relative to the supported part) of the rear end drop member 250 is fixed, and a second part 242b to which the base end (supported part; not necessarily the end of the member, and there may be a part that protrudes on the opposite side of the member from the front end of the member relative to the supported part) of the scraping arm 243 of the scraping part 240 is fixed, and the first part 242a and the second part 242b are connected to each other and can rotate together. Therefore, when the rear end drop member 250 moves upward due to the biasing force of the tension spring 252, the scraping arm 243 moves upward together with the rear end drop member 250.

[0175] For example, after moving the scraping section 240 and the rear end dropping member 250 to the second position, turning off the electromagnetic clutch CL1 causes the rear end dropping member 250 and the scraping section 240 to quickly rise towards the first position due to the tension spring 252. In other words, even without driving the lifting motor MT3, the scraping section 240 and the rear end dropping member 250 can be moved upward simply by turning off the electromagnetic clutch CL1. For example, to receive the next sheet, it is faster to turn off the electromagnetic clutch CL1 and move upward using the biasing force of the tension spring 252 than to move by driving the lifting motor MT3. Therefore, in this embodiment, the next sheet can be received into the processing tray 220 quickly, and productivity can be increased.

[0176] Here, the lifting and lowering operations of the discharge roller 230, the scraping section 240, and the rear end dropping member 250 will be explained using Figures 44(a) to 46(b). First, Figures 44(a) and 45(a) show the discharge roller 230 in the retracted position and the scraping section 240 and the rear end dropping member 250 in the first position. From the state shown in Figure 44(a), if the lifting motor MT3 is driven with the electromagnetic clutch CL1 turned OFF, only the discharge roller 230 will descend from the retracted position toward the contact position, as shown in Figure 44(b).

[0177] On the other hand, when the electromagnetic clutch CL1 is turned ON and the lifting motor MT3 is driven from the state shown in Figure 45(a), the discharge roller 230 descends toward the contact position, and the scraping section 240 and the rear end dropping member 250 also descend toward the second position, as shown in Figure 45(b). Next, when the electromagnetic clutch CL1 is turned OFF from the state shown in Figure 46(a), where the discharge roller 230 is in the contact position and the scraping section 240 and the rear end dropping member 250 are in the second position, the scraping section 240 and the rear end dropping member 250 move upward due to the tension spring 252, as shown in Figure 46(b). Thus, in this embodiment, by controlling the ON and OFF timing of the electromagnetic clutch CL1, the lifting timing of the discharge roller 230 and the scraping section 240 and the rear end dropping member 250 can be staggered.

[0178] As shown in Figure 47, the discharge arm 233A of the discharge roller 230 may be provided with a pivot shaft 233B in the middle, allowing the tip end to rotate relative to the pivot shaft 233B, and this tip end may be biased downward by a spring. In this case, even if the scraping section 240 and the rear end dropping member 250 descend after the discharge roller 230, the scraping section 240 and the rear end dropping member 250 can still make contact with the sheet on the processing tray 220.

[0179] In other words, when the discharge roller 230 is in the contact position, turning on the electromagnetic clutch CL1 and then driving the lifting motor MT3 will cause the discharge roller 230 to move downward from the contact position. With the configuration shown in Figure 47, if the discharge roller 230 tries to move further downward, the tip of the discharge arm 233A rotates around the pivot axis 233B, thereby allowing the discharge roller 230 to move. Therefore, even if the scraping section 240 and the rear end dropping member 250 descend after the discharge roller 230, the scraping section 240 and the rear end dropping member 250 can descend to a position where they can contact the sheet on the processing tray 220.

[0180] As shown in Figure 42, the transport motor MT2 is capable of transmitting power to a drive shaft 244 for driving the scraping belt 240a via a transmission belt 520. A pulley 521 is provided on the drive shaft 244 at a position between the scraping arms 243, and a drive belt 522 is stretched between this pulley 521 and the rollers 240c (Figure 43) that tension the scraping belt 240a. When the transport motor MT2 is driven, the drive shaft 244 rotates via the transmission belt 520, and the rollers 240c are rotated via the pulley 521 and drive belt 522 provided on the drive shaft 244. Then, the scraping belt 240a, which is tensioned by the rollers 240c, is rotated. As described above, since the drive shaft 244 is capable of relative rotation to the pivot shaft 242, the drive of the transport motor MT2 causes the drive shaft 244 to rotate freely relative to the pivot shaft 242.

[0181] Furthermore, the drive shaft 244 and the tension roller 261 that rotates the discharge belt 260 are connected by a drive transmission unit 523. The drive transmission unit 523 includes a pulley 523a provided on the drive shaft 244, a first intermediate pulley 523b, a first transmission belt 523c stretched between pulley 523a and the first intermediate pulley 523b, a second intermediate pulley 523d ​​that rotates integrally with the first intermediate pulley 523b, an electromagnetic clutch CL2, a pulley 523e driven and connected to the electromagnetic clutch CL2 by gears or the like, a second transmission belt 523f stretched between the second intermediate pulley 523d ​​and the pulley 523e, and a drive shaft 523g driven and connected to the electromagnetic clutch CL2. The tension roller 261 is provided on the drive shaft 523g.

[0182] Therefore, when the conveyor motor MT2 is driven, the first transmission belt 523c and the second transmission belt 523f rotate. When the electromagnetic clutch CL2 is ON, the drive of the conveyor motor MT2 is transmitted to the drive shaft 523g, causing the tension roller 261 to rotate and the discharge belt 260 to rotate. On the other hand, when the electromagnetic clutch CL2 is OFF, even if the conveyor motor MT2 is driven, the drive is not transmitted to the drive shaft 523g, and the discharge belt 260 does not rotate.

[0183] Furthermore, in this embodiment, the drive shaft 523g is also connected to the roller 321 that drives the sheet-holding belt 320. That is, the roller 321 is mounted on the drive shaft 523g, and rotates together with the tensioning roller 261 when the drive shaft 523g rotates. Therefore, when the electromagnetic clutch CL2 is ON and the transport motor MT2 is driven, the roller 321 rotates, and the sheet-holding belt 320 is also rotated. On the other hand, when the electromagnetic clutch CL2 is OFF, the sheet-holding belt 320 does not rotate even when the transport motor MT2 is driven.

[0184] Figure 48 shows the relationship between each motor and each component. The columns in Figure 48, from left to right, indicate the number, the name of the motor, the presence or absence of a clutch between the motor and the drive component, the drive component, operation, the state and direction of operation of the clutch during forward rotation, the state and direction of operation of the clutch during reverse rotation, and remarks. In Figure 48, the transport motors MT1 and MT2 and the lifting motor MT3 are as described above. As is clear from Figure 48, the transport motor MT1 drives the rollers (transport rollers) 212a that drive the transport belt 212, the pre-processing roller 211, and the return member 280. In other words, in this embodiment, the transport belt 212, the pre-processing roller 211, and the return member 280 all share the same drive source.

[0185] Furthermore, the conveyor motor MT2 drives the drive shaft 244 for driving the scraping belt 240a, the tension roller 261 for driving the discharge belt 260, and the drive shaft 523g for driving the sheet pressing belt 320. In other words, in this embodiment, the drive source for the scraping belt 240a, the discharge belt 260, and the sheet pressing belt 320 is the same. In addition, the lifting motor MT3 raises and lowers the discharge roller (nip member) 230, changes the nip pressure of the pre-processing roller 211, and raises and lowers the scraping section 240 and the rear end dropping member 250. In other words, in this embodiment, the raising and lowering of the discharge roller 230, the raising and lowering of the scraping section 240 and the rear end dropping member 250, and the change in the nip pressure of the pre-processing roller 211 are all performed by the same drive source.

[0186] In this embodiment, in addition to the above, a lifting motor MT4 for raising and lowering the return member 280, a alignment plate moving motor MT5 for moving the front alignment plate 271 in the width direction, a alignment plate moving motor MT6 for moving the rear alignment plate 271 in the width direction, an STP moving motor MT7 for moving the staple unit 400 to change the staple position, an STP clinch motor MT8 for driving the staple unit 400 to staple the sheet bundle, and a lifting motor MT9 for raising and lowering the loading tray 300.

[0187] [Control configuration for sheet processing device] The control configuration of the sheet processing apparatus 200 will be explained using Figure 49 and Figure 14 described above. Figure 49 is a block diagram showing the drive configuration of each motor and clutch, and each sensor of the sheet processing apparatus 200. The signals from each of these sensors are input to the control unit 203, which acts as a control means, and each drive configuration is controlled by the control unit 203. The control unit 203 is connected to the control unit of the image forming apparatus 100 in a communication manner and controls the entire sheet processing apparatus 200.

[0188] Such a control unit 203 includes a CPU (Central Processing Unit), ROM (Read Only Memory), and RAM (Random Access Memory). The CPU controls each part while reading programs corresponding to control procedures stored in ROM. The RAM stores working data and input data, and the CPU performs control by referring to the data stored in RAM based on the aforementioned programs, etc.

[0189] The motors, clutches, etc. shown in Figure 49 are as described above. On the other hand, each sensor will be explained with reference to Figure 37(b). First, the inlet sensor SN1 is provided on the transport path 210 and detects the leading edge of the sheet being transported on the transport path 210. The nip member HP position detection sensor SN2 is provided around the pivot shaft 232 as described above and detects that the discharge roller (nip member) 230 is in the retracted position (home position). The scraping section HP position detection sensor SN3 is provided around the pivot shaft 242 and detects that the scraping section 240 and the rear end drop member 250 are in the first position (home position). The knurled belt HP position detection sensor SN4 detects the position (home position) where the return member 280 has been retracted from the processing tray 220.

[0190] The front alignment plate HP position detection sensor SN5 and the rear alignment plate HP position detection sensor SN6 detect when the front alignment plate 271 and the rear alignment plate 271 are at a position (home position) separated in the width direction from the sheet placed on the processing tray 220, respectively. The stapler HP position detection sensor SN7 detects when the staple unit 400 is at its home position. The loading tray HP position detection sensor SN8 detects the home position of the loading tray 300. The loading tray lower limit position detection sensor SN9 detects the lower limit position of the loading tray 300. The processing tray sheet presence / absence detection sensor SN10 detects the presence or absence of a sheet on the processing tray 220. The control unit 203 performs the following controls based on the signals from each of these sensors.

[0191] Next, the control flow for each mode of this embodiment will be explained using Figure 14 described above. In this embodiment, there is a straight discharge mode in which the sheets sent to the sheet processing device 200 are discharged directly to the loading tray 300 without any predetermined processing; a shift mode in which the sheets sent to the sheet processing device 200 are moved in the width direction (shift operation) and discharged to the loading tray 300; and a staple mode in which the sheets sent to the sheet processing device 200 are stapled as a predetermined process and then discharged to the loading tray 300. Each of these modes is selected by the user.

[0192] Furthermore, the shift mode includes two types of shift operations: one for shifting to large-sized sheets where the length in the sheet transport direction (a predetermined direction) is longer than a predetermined length, and another for shifting to small-sized sheets where the length in the predetermined direction is less than or equal to a predetermined length. The predetermined length is, for example, the size of A4 paper when fed vertically (the direction in which the long side is the transport direction), commonly known as A4 portrait. In addition, in shift mode, it is possible to select and execute a productivity-priority mode that prioritizes productivity and an alignment-priority mode that prioritizes sheet alignment.

[0193] The first mode (first shift discharge processing), which prioritizes productivity, is a mode in which the sheet is aligned in the width direction by the alignment unit 270 while hanging down from the transport path 210 towards the processing tray. The second mode (second shift discharge processing), which prioritizes alignment, is a mode in which the sheet is placed on the processing tray 220 and the sheet is aligned in the width direction by the alignment unit 270 for sheets that are not stapled by the staple unit 400. A more detailed explanation of this point will be given later.

[0194] When control is initiated, the control unit 203 determines whether the discharge mode selected is straight discharge mode, shift mode, or staple mode (S1). If straight discharge mode is selected, the sheets sent to the sheet processing device 200 are discharged one by one into the loading tray 300 without any predetermined processing (S2).

[0195] In S1, if shift mode is selected, it is determined whether the sheet size is large or small (S3). If it is small, it is determined whether productivity is the priority (S4). If productivity is the priority, the sheets discharged from the transport path 210 are shifted without shifting in the processing tray 220, and discharged to the loading tray 300 with a portion of the transport path 210 remaining (S5). If productivity is not the priority in S4, the sheets discharged from the transport path 210 are scooped into the processing tray 220, and a shift operation is performed on the processing tray 220 before being discharged to the loading tray 300 (S6). If it is large in S3, the process proceeds to S6.

[0196] In S1, if the stapling mode is selected, the sheets discharged from the transport path 210 are fed into the processing tray 220 and aligned to form a sheet bundle on the processing tray 220 (S7). Then, the sheet bundle is stapled (S8). After that, the sheet bundle is discharged into the loading tray 300 (S9).

[0197] The operation of the sheet processing device 200 in each of the above modes will be explained with reference to Figures 50 to 74.

[0198] [Straight discharge mode] The straight discharge mode will be explained using Figures 50 to 53. As shown in Figures 50(a) and (b), when the sheet S is being transported on the transport path 210, the discharge roller 230 is in the retracted position, and the scraping section 240 and the rear end drop member 250 are in the first position. Next, as shown in Figures 51(a) and (b), the sheet S is discharged in a predetermined direction from the pre-processing roller 211 located at the downstream end of the transport path 210 in a predetermined direction and from the pre-processing nip section 211a of the transport belt 212. In this state as well, the discharge roller 230 is in the retracted position, and the scraping section 240 and the rear end drop member 250 are in the first position.

[0199] When a predetermined amount of sheet S is conveyed from the pre-processing nip section 211a, the discharge roller 230 descends to a contact position, as shown in Figures 52(a) and (b), and grips sheet S between the discharge roller 230 and the discharge belt 260. At this time, the rear end of sheet S does not pass through the pre-processing nip section 211a. Therefore, sheet S is held between the discharge nip section 230a and the pre-processing nip section 211a between the discharge roller 230 and the discharge belt 260. However, as described above, when the discharge roller 230 descends to the contact position, the nip pressure of the pre-processing roller 211 becomes almost zero. Therefore, sheet S is mainly held and conveyed between the discharge roller 230 and the discharge belt 260, and as shown in Figures 53(a) and (b), it is discharged directly to the loading tray 300 without being loaded onto the pre-processing roller 211.

[0200] [Shift Mode (Productivity Priority)] The productivity priority mode among the shift modes will be explained using Figures 54 to 58. As shown in Figures 54(a) and (b), when the sheet S is being transported on the transport path 210, the discharge roller 230 is in the retracted position, and the scraping section 240 and the rear end drop member 250 are in the first position. Next, as shown in Figures 55(a) and (b), after the downstream end (front) of the sheet S in the sheet transport direction passes through the pre-processing nip section 211a between the pre-processing roller 211 and the transport belt 212, and the upstream end (rear end) of the sheet S in the sheet transport direction passes through the nip section between the upstream roller 213 as the third rotating body and the transport belt 212, the nip pressure of the pre-processing roller 211 is changed from the first pressure (first nip pressure) to the second pressure (second nip pressure). That is, the nip pressure is set to approximately 0. Furthermore, the timing for starting the change from the first pressure to the second pressure may be before the upstream end in the sheet conveying direction passes the nip between the upstream roller 213 and the conveying belt 212, or the change to the second pressure may be completed after the upstream end in the sheet conveying direction has passed the nip between the upstream roller 213 and the conveying belt 212.

[0201] In this embodiment, once the rear end of the sheet S passes the inlet sensor SN1 on the transport path 210, the discharge roller 230 begins to descend and move toward the guide position. This reduces the nip pressure of the pre-processing roller 211 to approximately zero. Also, once the rear end of the sheet S passes the inlet sensor SN1 on the transport path 210, the front and rear alignment plates 271 begin to move toward the widthwise edge of the sheet S. In this state, the sheet S hangs down from the transport path 210 toward the processing tray 220, and the widthwise edge of this hanging portion comes into contact with the first contact portion 272 of the alignment plate 271, performing widthwise alignment. At this time, since the nip pressure of the pre-processing roller 211 is approximately zero, the alignment plate 271 smoothly aligns the sheet. In other words, when the alignment unit 270 aligns the widthwise sheet hanging down from the transport path 210, the nip pressure of the pre-processing roller 211 is adjusted to approximately zero.

[0202] Next, as the sheet S is further transported, as shown in Figures 56(a) and (b), the leading edge of the sheet S is guided downward by the discharge arm 233 of the discharge roller 230, which has moved to a guide position (while moving). Then, at the moment when the leading edge of the sheet S passes the downstream end of the discharge belt 260 in a predetermined direction, the upper surface of the sheet S is pressed against the discharge roller 230. At this time, the sheet S is transported by the conveyor belt 212 because the nip pressure of the pre-processing roller 211 is almost zero. Since the sheet S is resting on the conveyor belt 212 by its own weight, and a certain amount of contact area is secured between the sheet S and the conveyor belt 212, the sheet S can be transported downstream in a predetermined direction by the conveyor belt 212.

[0203] As shown in Figures 56(a) and (b), the discharge roller 230 pushes the leading edge of the sheet S downward in the width direction, so that the leading edge of the sheet S in the width direction faces the second contact portion 273 of the alignment plate 271. Also, the rear end of the sheet S does not pass through the pre-processing nip portion 211a. In productivity priority mode, in this state, the first contact portion 272 and the second contact portion 273 of the pair of alignment plates 271 are brought into contact with the width direction edge of the sheet, and the sheet S is shifted in the desired direction. That is, in productivity priority mode of this embodiment, the sheet S is not placed on the processing tray 220, but hangs down from the transport path 210, and the first contact portion 272 and the second contact portion 273, which are two contact portions of the pair of alignment plates 271 spaced apart in a predetermined direction, are brought into contact with the width direction edge of the sheet S. In this process, the first contact portion 272 contacts the curved portion of the sheet SL that hangs down from the transport path 210, and the second contact portion 273 contacts the leading edge of the sheet SL. Then, by moving the pair of alignment plates 271 in the desired direction, the sheet S is moved in the width direction (shift direction).

[0204] Once the sheet S has moved in the width direction (shift operation) is complete, the discharge roller 230 is lowered from the guide position to the contact position, as shown in Figures 57(a) and (b), and the sheet S is clamped between the discharge roller 230 and the discharge belt 260. The sheet S is then transported mainly by the discharge roller 230 and the discharge belt 260, and the sheet S is discharged into the loading tray 300, as shown in Figures 58(a) and (b).

[0205] In this productivity-prioritizing mode, there is no operation to place the sheet S on the processing tray 220, so the sheet S shift operation can be performed faster than when it is performed on the processing tray 220. In addition, during the shift operation, the sheet S is brought into contact with the alignment plate 271 in a sagging and curved state, so the sheet S can be aligned and shifted in a more rigid state, and the alignment and shift operations can be performed in a state in which the sheet is less likely to bend.

[0206] Furthermore, in this embodiment, the leading edge of the sheet S is pushed down by moving the discharge roller 230 to the guide position, allowing it to more reliably contact the second contact portion 273 of the alignment plate 271. By having the alignment plate 271 contact two widthwise edges of the sheet S that are spaced apart in a predetermined direction, the sheet S can be shifted in a more stable manner. In other words, the sheet can be moved in the width direction while suppressing skew during the shift operation.

[0207] The productivity priority mode is preferably applicable to small-sized sheets, but may also be used for large-sized sheets. Furthermore, for example, if the length of the sheet in a given direction is short, the shift operation may be performed by bringing only the first contact portion 272 into contact with the widthwise edge of the sheet.

[0208] Furthermore, in the above example, in the first shift discharge process, the shift operation was performed with the nip pressure of the pre-processing roller 211 set to a second nip pressure, which is weaker than the first nip pressure. However, the shift operation may also be performed with the pre-processing roller 211 separated from the conveyor belt 212. For example, the configuration in which the lifting motor MT3 moves the pre-processing roller 211 may be made to function as a conveying rotating body moving member that moves the pre-processing roller 211 from a clamping position where it clamps the sheet between the pre-processing roller 211 and the conveyor belt 212 to a separated position where the pre-processing roller 211 and the conveyor belt 212 are separated from each other. The shift operation may then be performed with the pre-processing roller 211 in the separated position.

[0209] [Shift Mode (Alignment Priority)] Figures 59 to 65 will be used to explain the alignment priority mode among the shift modes. Note that the alignment priority mode may be used for small-sized sheets, but here we will explain its use for large-sized sheets. As shown in Figures 59(a) and (b), when the sheet SL is being transported on the transport path 210, the discharge roller 230 is in the retracted position, and the scraping section 240 and the rear end drop member 250 are in the first position.

[0210] As shown in Figures 60(a) and (b), when the rear end of sheet SL passes the pre-processing nip section 211a, the discharge roller 230, scraping section 240, and rear end dropping member 250 begin to descend. Note that the timing of the start of the descent of the discharge roller 230, scraping section 240, and rear end dropping member 250 may be before the rear end of sheet SL passes the pre-processing nip section 211a. In any case, it is sufficient that the timing coincides with the rear end of sheet SL passing the pre-processing nip section 211a when the scraping section 240 and rear end dropping member 250 drop the rear end of sheet SL toward the processing tray 220.

[0211] As shown in Figures 61(a) and (b), the discharge roller 230 moves to the contact position, and the scraping section 240 and the rear end dropping member 250 move down to the second position. As a result, the sheet SL discharged from the transport path 210 is held between the discharge roller 230 and the discharge belt 260, and its rear end is dropped toward the processing tray 220 by the scraping section 240 and the rear end dropping member 250, where it is placed. At this time, the sheet SL is also held between the scraping belt 240a of the scraping section 240 and the discharge belt 260.

[0212] Next, as shown in Figures 62(a) and (b), the scraping belt 240a and the discharge belt 260 are rotated in opposite directions to transport the sheet SL placed on the processing tray 220 toward the rear end regulating member 290. At this time, the return member 280 descends, and the knurled belt 281 of the return member 280 comes into contact with the upper surface of the rear end of the sheet SL. Then, by rotating the knurled belt 281, the sheet SL is transported further, and the rear end of the sheet SL abuts against the rear end regulating member 290. This aligns the sheet SL in a predetermined direction.

[0213] Next, as shown in Figures 63(a) and (b), the discharge roller 230 is raised to the retracted position, the scraping section 240 and the rear end dropping member 250 are raised to the first position, and the return member 280 is raised, thereby retracting each of these members from the upper surface of the sheet SL. In this state, the front and rear alignment plates 271 are moved in the width direction (shift direction) to perform width alignment and shifting operations on the sheet SL. At this time, since the sheet SL is placed on the processing tray 220, it comes into contact with the second contact portion 273 of the alignment plate 271. The second contact portion 273 is positioned below the first contact portion 272 and extends downstream of the first contact portion 272 in a predetermined direction, and comes into contact with the widthwise edge of the sheet SL over a relatively wide range in that predetermined direction. Furthermore, the second contact portion 273 contacts the widthwise edge of the sheet SL, which is placed on the processing tray 220, with the leading edge of the sheet SL protruding towards the loading tray 300 beyond the downstream end of the processing tray 220 in a predetermined direction.

[0214] Once the sheet SL has completed its shifting operation, the discharge roller 230 is lowered to the contact position, as shown in Figures 64(a) and (b), to clamp the sheet SL between the discharge roller 230 and the discharge belt 260. Then, by rotating the discharge belt 260 in the forward direction, the sheet SL is discharged from the processing tray 220 to the loading tray 300, as shown in Figures 65(a) and (b).

[0215] In this alignment-priority mode, the sheet SL is aligned and shifted on the processing tray 220, resulting in better alignment of the sheet SL than in the productivity-priority mode. In particular, in alignment-priority mode, the sheet SL is placed on the processing tray 220, the rear end of the sheet SL is abutted against the rear end regulating member 290, and the entire area of ​​the second contact portion 273 in a predetermined direction is brought into contact with the widthwise edge of the sheet SL to perform the shifting operation. The length of the entire area of ​​the second contact portion 273 in a predetermined direction is longer than the combined length of the first contact portion 272 that contacts the sheet in productivity-priority mode and a part of the second contact portion, so in alignment-priority mode, the alignment plate 271 can contact the widthwise edge of the sheet over a wide area.

[0216] Furthermore, in productivity-priority mode, the sheet shifts while hanging down from the transport path 210, whereas in alignment-priority mode, the sheet shifts while resting on the processing tray 220, allowing for a more stable sheet shift operation. Additionally, since the leading edge of the sheet SL protrudes further towards the loading tray 300 than the processing tray 220, the leading edge of the sheet SL hangs down onto the loading tray 300 and is curved. Therefore, the sheet SL can shift with greater rigidity than when it is not curved. For these reasons, the alignment of the sheet SL can be improved in alignment-priority mode compared to productivity-priority mode.

[0217] However, in alignment priority mode, the sheet is first placed on the processing tray 220, which takes longer to process compared to productivity priority mode. However, in the case of large-sized sheets, processing within the image forming apparatus 100 also takes time. Therefore, when alignment priority mode is executed for large-sized sheets, the shift operation can be performed at a productivity level suitable for the productivity of the image forming apparatus 100, and furthermore, the alignment of the sheets can be improved. Note that even with large-sized sheets, the productivity priority mode described above may be executed.

[0218] [Staple Mode] The stapling mode will be explained using Figures 66 to 74. As shown in Figures 66(a) and (b), when the first sheet S1 is transported on the transport path 210, the discharge roller 230 is in the retracted position, and the scraping section 240 and the rear end drop member 250 are in the first position. When the rear end of the sheet S1 passes the pre-processing nip section 211a, the discharge roller 230, scraping section 240 and rear end drop member 250 begin to descend, as in Figure 60 above, and as in Figure 61, the discharge roller 230 descends to the contact position, and the scraping section 240 and rear end drop member 250 descend to the second position. That is, the sheet S1 discharged from the transport path 210 is placed on the processing tray 220, and the sheet S1 is clamped between the discharge roller 230 and the discharge belt 260, as well as between the scraping belt 240a of the scraping section 240 and the discharge belt 260. Furthermore, the timing for the discharge roller 230, scraping section 240, and rear end dropping member 250 to begin descending may be before the rear end of the sheet S1 passes the pre-processing nip section 211a.

[0219] Next, as shown in Figures 67(a) and (b), the scraping belt 240a and the discharge belt 260 are rotated in opposite directions to transport the sheet S1 placed on the processing tray 220 toward the rear end regulating member 290. At this time, the return member 280 descends, and the knurled belt 281 of the return member 280 comes into contact with the upper surface of the rear end of the sheet S1. Then, by rotating the knurled belt 281, the sheet S1 is transported further, and the rear end of the sheet S1 abuts against the rear end regulating member 290. This aligns the sheet S1 in a predetermined direction.

[0220] Next, as shown in Figures 68(a) and (b), the discharge roller 230 is raised to the retracted position, the scraping section 240 and the rear end drop member 250 are raised to the first position, and the return member 280 is also raised, thereby retracting each of these members from the upper surface of the sheet S1. In this state, the front and rear alignment plates 271 are moved in the width direction to align the sheet S1 in the width direction. At this time, since the sheet S1 is placed on the processing tray 220, it comes into contact with the second contact portion 273 of the alignment plate 271. Up to this point, it is the same as the alignment priority mode.

[0221] Next, as shown in FIGS. 69(a) and (b), in order to provide the second sheet, the return member 280 is lowered to sandwich the rear end of the sheet S1 between the ratchet belt 281 and the processing tray 220. Thereby, even when the second sheet is conveyed onto the processing tray 220, it is possible to prevent the first sheet S1 from shifting. In this state, the second sheet S2 discharged from the conveyance path 210 is placed on the sheet S1 placed on the processing tray 220 in the same manner as when the above-described first sheet S1 is placed on the processing tray 220.

[0222] Then, as shown in FIGS. 70(a) and (b), the scraping belt 240a and the discharge belt 260 are rotated in opposite directions to convey the first sheet S2 placed on the processing tray 220 toward the rear end regulating member 290. At this time, the return member 280 once rises and descends at the timing when the rear end of the sheet S2 reaches the return member 280. Then, the ratchet belt 281 of the return member 280 abuts on the upper surface on the rear end side of the sheet S2. By rotating the ratchet belt 281, the sheet S2 is further conveyed, and the rear end of the sheet S2 is abutted against the rear end regulating member 290. Thereby, alignment of the sheet S2 in a predetermined direction is performed. When the sheet placed on the processing tray 220 is the second sheet or later, only the scraping belt 240a is rotated in the reverse direction without rotating the discharge belt 260, and the rear end of the sheet is abutted against the rear end regulating member 290 in the same manner as the first sheet. In addition, even when the rear end of the first sheet is abutted against the rear end regulating member 290, only the scraping belt 240a may be rotated in the reverse direction without rotating the discharge belt 260.

[0223] Next, as shown in FIGS. 71(a) and 71(b), the discharge roller 230 is moved to the retracted position, the scraping-in part 240 and the rear-end dropping member 250 are each raised to the first position, and the returning member 280 is raised, and these members are retracted from the upper surface of the sheet S2. In this state, the front and rear alignment plates 271 are moved in the width direction to align the sheet S2 in the width direction. The operation of placing the sheet on the processing tray 220 and aligning the sheet on the processing tray 220 is performed for the number of sheets based on the input job information, and a sheet stack ST is formed on the processing tray 220.

[0224] After forming the sheet stack ST, as shown in FIGS. 72(a) and 72(b), the stapler unit 400 is driven to staple the sheet stack ST. After performing the stapling process, as shown in FIGS. 73(a) and 73(b), the front and rear alignment plates 271 are retracted from the widthwise edge of the sheet stack ST, the discharge roller 230 is moved to the contact position, and the scraping-in part 240 is lowered to the second position. As a result, the sheet stack ST is sandwiched between the discharge roller 230 and the scraping-in belt 240a and the discharge belt 260. Then, by driving the discharge belt 260 and the scraping-in belt 240a, as shown in FIGS. 74(a) and 74(b), the sheet stack ST is discharged from the processing tray 220 to the stacking tray 300.

[0225] Thus, in this embodiment, the discharge of the sheet stack ST is performed by driving the scraping-in belt 240a in addition to the conveyance by the discharge roller 230 and the discharge belt 260. In particular, since the tensioning surface of the scraping-in belt 240a contacts the upper surface of the sheet stack ST, the conveyance force of the sheet stack ST is high. Therefore, the discharge of the sheet stack ST from the processing tray 220 can be performed more reliably.

[0226] To increase the sheet transport force, it is conceivable to increase the contact pressure (nip pressure) of the discharge roller 230 against the discharge belt 260. However, in this case, it is necessary to ensure the strength of the structure supporting the discharge roller 230, which would increase the size of the device. Also, if the discharge roller 230 is pressed too hard against the sheet, there is a risk of ink bleeding through to the back. Therefore, in this embodiment, a scraping belt 240a is pressed against the sheet separately from the discharge roller 230, and the scraping belt 240a assists in the discharge of the sheet.

[0227] Therefore, the nip pressure of the discharge roller 230 does not need to be increased unnecessarily, which suppresses the size increase of the device and also suppresses the occurrence of back-side printing. In addition, the scraping belt 240a has the function of transporting the sheet on the processing tray 220 toward the rear end restricting member 290, and only the rotation direction of the scraping belt 240a is switched when transporting the sheet toward the rear end restricting member 290 and when discharging the sheet. Therefore, the device can be made smaller than when separate components for each function are provided.

[0228] [Sheet ejection operation] The operation of discharging the sheets to the loading tray 300 in this embodiment will be explained with reference to Figures 75 to 79. First, as shown in Figures 75(a) and (b), the sheets S are picked up and transported between the discharge roller 230 and the discharge belt 260, and then discharged to the loading tray 300. At this time, the loading tray 300 is in the first loading position. The first loading position is the home position when no sheets are loaded on the loading tray 300, and when sheets are loaded, it is a position determined according to the amount of sheets loaded.

[0229] Next, the loading tray 300 descends from the first loading position to the second loading position so that the downstream end (tip) of the sheet S discharged by the discharge roller 230 and discharge belt 260 in a predetermined direction comes into contact with the sheet mounting surface 301 of the loading tray 300 or the sheet placed on the sheet mounting surface 301. In this embodiment, as shown in Figures 76(a) and (b), once the rear end of the sheet S passes through the discharge nip portion 230a between the discharge roller 230 and the discharge belt 260, the loading tray 300 begins to descend from the first loading position to the second loading position. The sheet retaining belt 320 is stretched over the roller 321 in a flexed state. Therefore, when the loading tray 300 is in the first loading position, the sheet retaining belt 320 is slightly pushed up by the sheet placed on the loading tray 300. Even if the loading tray 300 descends from the first loading position to the second loading position from this state, the sheet-holding belt 320 remains in contact with the sheet on the loading tray 300 until the sag of the sheet-holding belt 320 is eliminated. Therefore, the sheet-holding effect of the sheet-holding belt 320 continues for a predetermined section from the time the loading tray 300 begins to descend.

[0230] When the sheet S is discharged from the discharge nip section 230a, as shown in Figures 77(a) and (b), the sheet holding belt 320 rotates and contacts the upstream end (rear end) of the sheet S being discharged by the discharge roller 230 and the discharge belt 260 in a predetermined direction, thereby guiding the rear end of the sheet S toward the loading tray 300.

[0231] As described above, the sheet retaining belt 320 is a knurled belt, and a roller for driving the sheet retaining belt 320 is also provided on the drive shaft 261a of the tensioning roller 261 that drives the discharge belt 260. Therefore, the sheet retaining belt 320 rotates in sync with the discharge belt 260. In addition, at least a portion of the sheet retaining belt 320 is provided to protrude downstream in a predetermined direction from the vertical surface 310, and below the sheet mounting surface of the processing tray 220. Therefore, as the sheet retaining belt 320 rotates, the rear end of the sheet S that has passed through the discharge nip section 230a is guided to the loading tray 300 so that it is scraped off by the sheet retaining belt 320. That is, as shown by the dotted and dashed lines in Figure 77(b), the rear end of the sheet S is scraped off by the sheet retaining belt 320. This makes it less likely for the rear end of the sheet S to remain in the discharge nip section 230a.

[0232] Next, after the upstream end of the sheet S in a predetermined direction is discharged onto the sheet mounting surface 301 or onto a sheet placed on the sheet mounting surface 301, the loading tray 300 rises from the second loading position to the first loading position so that the loading tray 300 reaches the first loading position. In this embodiment, as shown in Figures 78(a) and (b), after the rear end of the sheet S is discharged onto the loading tray 300, the loading tray 300 begins to rise from the second loading position towards the first loading position. As the loading tray 300 rises from the second loading position to the first loading position in this way, the sheet holding belt 320 presses down on the upper surface of the rear end of the sheet S that has been discharged onto the loading tray 300.

[0233] Next, as shown in Figures 79(a) and (b), the sheet-holding belt 320 transports the sheet S on the loading tray 300, which has risen from the second loading position to the first loading position, toward the vertical surface 310, which serves as a loading-side restricting means. That is, as the sheet-holding belt 320 rotates, it grips the sheet S on the loading tray 300, causing the rear end of the sheet S to abut against the vertical surface 310. At this time, the sheet-holding belt 320 may be in contact with the upper surface of the sheet S while rotating, or it may rotate after it has come into contact with the upper surface of the sheet S. In other words, when the loading tray 300 rises from the second loading position to the first loading position, the rotation of the sheet-holding belt 320 may begin at least before the loading tray 300 reaches the first loading position, or the rotation of the sheet-holding belt 320 may begin after the loading tray 300 reaches the first loading position. In any case, the rotation of the seat retaining belt 320 is stopped at the moment the rear end of the seat S hits the vertical surface 310.

[0234] In this embodiment, the upper surface of the sheet S discharged onto the loading tray 300 is held down by the sheet holding belt 320. For this purpose, the loading tray 300 is made capable of moving up and down between a first loading position and a second loading position, and the timing of its descent from the first loading position and rise from the second loading position is controlled as described above in accordance with the discharge of the sheets. Furthermore, the sheet holding belt 320, provided at the downstream end of the processing tray 220 in a predetermined direction, is used to hold down the upper surface of the rear end of the sheet discharged onto the loading tray 300.

[0235] This prevents the sheet S from shifting even when the next sheet is discharged onto the sheet S placed on the loading tray 300. Depending on the angle of the loading tray 300, the rear end of the previously discharged sheet S may be held down by the sheet retaining belt 320 after the leading edge of the next sheet has made contact. That is, when the sheet placement surface 301 of the loading tray 300 is inclined with respect to the horizontal plane such that the downstream side in a predetermined direction is upward, and this angle is large, the sheet is less likely to shift even if the leading edge of the next sheet contacts the upper surface of the sheet already placed on it. Therefore, in such cases, the next sheet may be discharged in such a way that the leading edge of the next sheet contacts the sheet S before the loading tray 300 on which the sheet S is placed reaches the first loading position.

[0236] In any case, in this embodiment, the sheet holding belt 320 has the function of holding down the rear end of the sheet S discharged onto the loading tray 300, and the function of scraping off the rear end of the sheet S so that it does not remain on the discharge nip portion 230a. For this reason, in this embodiment, costs can be reduced compared to the case in which separate mechanisms for each of these functions are provided.

[0237] In this embodiment as well, when performing the staple mode, first shift discharge process, and second shift discharge process, the front-side matching plate moving motor MT5 and the rear-side matching plate moving motor MT6, which are common drive sources, and the common matching plate 271 are used to perform each process. Therefore, compared to a configuration that requires separate matching plates and drive sources for each process, costs can be reduced, and productivity can be improved for a given sheet by performing the first shift discharge process. It should also be noted that, as in the first embodiment, the first shift discharge process can be applied to all sheets that are shifted and discharged without stapling.

[0238] <Other Embodiments> Furthermore, the present invention is also applicable to the configurations shown in Figures 80, 81, and 82(a) to 83(b). Note that components similar to those in the first embodiment are denoted by the same reference numerals and their descriptions are omitted.

[0239] The sheet processing device shown in Figure 80 is a modified version of the first embodiment, with the upper discharge roller 230A and lower discharge roller 230B removed and an extrusion member 291 added as a discharge section. In this sheet processing device, the sheet S, which has been transported in a first transport direction (from right to left in the figure) by the pre-processing rollers 211A and 212A (first transport section) and placed on the processing tray 220, is transported in a second transport direction (from left to right in the figure) by the scraping paddle 240A and the knurled belt 281 of the return member 280 (together forming the second transport section), and the rear end of the sheet S is brought into contact with the rear end regulating member 290, which is a stopper section. After that, the width direction of the sheet S is aligned with a pair of alignment plates 271A, and the next sheet S is received and the above operation is repeated to create a sheet bundle, which is then stapled with a staple unit 400. Subsequently, the extrusion member 291 engages with the rear end of the sheet bundle (the upstream end in the first conveying direction) and moves in the first conveying direction, thereby discharging the sheet bundle into the loading tray 300.

[0240] When performing the first shift discharge process with such a sheet processing device, the pre-processing rollers 211A and 212A transport the sheet S in the first conveying direction, and when the rear end of the sheet S passes the pre-processing nip portion 211a of the pre-processing roller, the pair of alignment plates 271A shift the sheet S in the shift direction (at which point the scraping paddle 240A may be lowered slightly so that the rear end of the sheet S contacts the pair of alignment plates 271A), and then the extrusion member 291 discharges the sheet S into the loading tray 300.

[0241] Then, when performing the second shift discharge process, the pre-processing rollers 211A and 212A transport the sheet S in the first transport direction, and once the rear end of the sheet S passes the pre-processing nip portion 211a of the pre-processing roller and is placed on the sheet S processing tray 220, the scraping paddle 240A and knurled belt 281 transport the sheet S in the second transport direction, and the rear end of the sheet S abuts against the rear end regulating member 290, which is a stopper. After that, the pair of alignment plates 271A shift the sheet S in the shift direction, and then the extrusion member 291 discharges the sheet S to the loading tray 300.

[0242] The sheet processing apparatus shown in Figure 81 is a modified version of the first embodiment with the addition of an extrusion member 291. This sheet processing apparatus uses pre-processing rollers 211A and 212A (first conveying section) to convey sheets S in a first conveying direction (from right to left in the figure) and place them on a processing tray 220. The sheets S are then conveyed in a second conveying direction (from left to right in the figure) by a scraping paddle 240A and a knurled belt 281 of a return member 280 (together forming the second conveying section), causing the rear end of the sheet S to abut against a rear end regulating member 290, which is a stopper. Subsequently, a pair of alignment plates 271A align the width of the sheets S, and the next sheet S is received and the above operation is repeated to create a sheet bundle. The sheet bundle is then stapled using a staple unit 400. Subsequently, the extrusion member 291 engages with the rear end of the sheet bundle (the upstream end in the first conveying direction) and moves in the first conveying direction to extrude it. In this state, the upper discharge roller 230A and the lower discharge roller 230B are moved to a clamping position, and at least one of the upper discharge roller 230A and the lower discharge roller 230B is rotated to discharge the sheet bundle into the loading tray 300.

[0243] When performing the first shift discharge process with such a sheet processing device, the pre-processing rollers 211A and 212A transport the sheet S in the first transport direction, and it is handed over to the upper discharge roller 230A and the lower discharge roller 230B. Once the rear end of the sheet S has passed the pre-processing nip portion 211a of the pre-processing roller, the upper discharge roller 230A and the lower discharge roller 230B are moved to a separated position, and the pair of alignment plates 271A shift the sheet S in the shift direction. After that, the upper discharge roller 230A and the lower discharge roller 230B move to a clamping position and rotate to discharge the sheet S into the loading tray 300.

[0244] When performing the second shift discharge process, before the process, rollers 211A and 212A convey the sheet S in the first conveyance direction. When the rear end of the sheet S passes through the pre-process nip portion 211a of the pre-process roller and is placed on the sheet S processing tray 220, the scraping paddle 240A and the knurled belt 281 convey the sheet S in the second conveyance direction, and the rear end of the sheet S is abutted against the rear end regulating member 290 which is the abutting portion. Thereafter, with the upper discharge roller 230A and the lower discharge roller 230B in the separated position, the sheet S is shifted in the shift direction by the pair of alignment plates 271A, and then the sheet S is discharged to the stacking tray 300 by the pushing member 291. At that time, the sheet S may be discharged to the stacking tray 300 only by the pushing member 291, or the sheet S may be pushed out halfway by the pushing member 291 and then discharged to the stacking tray 300 by the upper discharge roller 230A and the lower discharge roller 230B from the middle.

[0245] Also, in the sheet processing apparatus shown in FIGS. 80 and 81 as well, the alignment of the stapling process, the first shift discharge process, and the second shift discharge process can be realized at low cost using the common alignment plate 271A.

[0246] Further, the sheet processing apparatus shown in FIGS. 82(a) to 83(b) is obtained by adding a second rear end dropping member 234 that moves in conjunction with the movement of the upper discharge roller 230A to the mechanical configuration of the first embodiment. The second rear end dropping member 234 is rotatably provided on the rotation shaft 2301 of the upper discharge roller 230A. The tip of the second rear end dropping member 234 (the end on the upstream side in the first conveyance direction) is positioned vertically above the lower surface of the discharge arm 2302 when the upper discharge roller 230A is in the retracted position, as shown in FIG. 82(a). Then, as shown in FIG. 82(b), the tip of the second rear end dropping member 234 rotates in a direction away from the discharge arm 2302, that is, in a direction approaching the processing tray 220 as the upper discharge roller 230A moves to the clamping position.

[0247] The second rear end drop member 234 operates in conjunction with the rotation of the upper discharge roller 230A. This mechanism will be explained using Figures 83(a) and (b). Figures 83(a) and (b) are schematic diagrams showing the relationship between the discharge arm 2302 that supports the upper discharge roller 230A and the second rear end drop member 234. The pivot axis 234a of the second rear end drop member 234 is provided coaxially with the rotation axis 230A1 of the upper discharge roller 230A and is rotatable relative to the rotation axis 230A1. Therefore, even if the upper discharge roller 230A rotates, the pivot axis 234a does not rotate. A pulley 234b is fixed to the pivot shaft 234a, and when the pulley 234b rotates, the pivot shaft 234a also rotates, and the second rear end drop member 234, whose base end (supported portion; not necessarily the end of the member, and there may be a portion that protrudes on the side opposite to the front end of the member relative to the supported portion; the end on the downstream side in the first conveying direction) is fixed to the pivot shaft 234a, also rotates.

[0248] On the other hand, a pulley 234c is fixed coaxially with the pivot shaft 2301 on the upstream side of the discharge arm 2302 in the first transport direction. The pulley 234c is rotatable relative to the pivot shaft 2301 and does not rotate even when the pivot shaft 2301 rotates. An endless belt 234d is stretched between pulleys 234b and 234c. When the discharge arm 2302 rotates around the pivot shaft 2301, the relative position of pulley 234b with respect to pulley 234c changes, causing belt 234d to rotate, and this rotation of belt 234d causes pulley 234b to rotate. Then, as the pivot shaft 234a rotates together with pulley 234b, the second rear end drop member 234 swings up and down.

[0249] Figure 83(a) shows the upper discharge roller 230A in its home position, at which point the second rear end drop member 234 is approximately parallel to the discharge arm 2302. This position is defined as the upper position of the second rear end drop member 234. To move the upper discharge roller 230A from this position to the clamping position, the discharge arm 2302 is rotated downward around the pivot axis 2301. As shown in Figure 83(b), the belt 234d travels in the direction of arrow P, and the pulley 234b and the rear end drop member 234 rotate in the direction of arrow Q around the pivot axis 234a. That is, the tip of the rear end drop member 234 moves from the upper position shown in Figure 83(a) to the lower position shown in Figure 83(b). In this manner, the second rear end drop member 234 moves in conjunction with the rotation of the discharge arm 2302 so as to be positioned upward when the upper discharge roller 230A is in the home position, and downward when the upper discharge roller 230A is in the clamping position.

[0250] The second rear end drop member 234, operating in this manner, presses down on the rear end of the sheet S from above during the first shift discharge process, thereby positioning the rear edge of the sheet S to be more easily contacted by the pair of alignment plates 271A. Furthermore, the sheet S curves beyond the discharge nip portion 230a on the rear end side, and the pair of alignment plates 271A contact this curved portion to shift the sheet S, allowing the shift operation to be performed with higher rigidity of the sheet S.

[0251] Figure 82(a) shows the state in which the upper discharge roller 230A receives the sheet in the retracted position. In this state, the tip of the second rear end drop member 234 is positioned vertically above the lower surface of the discharge arm 2032, so that the tip of the sheet S does not get stuck between the discharge arm 2302 and the second rear end drop member 234. Once the tip of the sheet S has passed between the upper discharge roller 230A and the lower discharge roller 230B, as shown in Figure 82(b), the upper discharge roller 230A is moved to the gripping position to transport the sheet S until the rear end passes the pre-processing nip section 211a. At that time, the second rear end drop member 234 moves from the upper position to the lower position in conjunction with the movement of the upper discharge roller 230A, dropping the rear end of the sheet S from above downwards. As described above, the rear end drop member 250A is not operated in the first shift discharge process. By providing such a second rear end drop member 234, the sheet S can be reliably dropped onto the processing tray 220 even in the first shift discharge process. Furthermore, the matching plates 271A can be reliably brought into contact with the sheet S during the shift operation of the sheet S by the pair of matching plates 271A described below.

[0252] Once the sheet S is dropped onto the processing tray 220 by the second rear drop member 234, the upper discharge roller 230A is moved to a separated position, as shown in Figure 28(c), and the pair of alignment plates 271A move the sheet S in the shift direction. In Figure 82(c), the second rear drop member 234 is not in contact with the upper surface of the sheet S when the upper discharge roller 230A is in a separated position, but the second rear drop member 234 may press down on the upper surface of the sheet to an extent that does not load the shift operation by the pair of alignment plates 271A.

[0253] In the first embodiment described above, the rear end drop member 250A is configured not to move to a lower position when the upper discharge roller 230A descends to a clamping or separated position. In this case, the first shift discharge process can be made more stable by providing a second rear end drop member 234. Alternatively, the rear end drop member 250A may be driven separately so that it is positioned in a lowered position when the seat shifts. Furthermore, if the second rear end drop member 234 is driven separately from the rotation of the upper discharge roller 230A, the rear end drop member 250A may be omitted.

[0254] Furthermore, although the second rear end drop member 234 is rotatably mounted on the pivot shaft 2301 of the upper discharge roller 230A, it may be mounted on a different member or configured to be independently movable. In other words, it is sufficient if the rear end of the sheet can be lowered downward to a position where the side edge of the rear end of the sheet can contact the pair of alignment plates 271A during the sheet shifting operation by the pair of alignment plates 271A.

[0255] Furthermore, in the embodiments described above, examples were shown in which a pair of alignment plates 271A (271) move in the shift direction while gripping both edges in the sheet width direction during the first shift discharge process. However, the following operations are also applicable. (1) to (5) below describe the operation of the pair of alignment plates when the sheet has been conveyed in the first conveying direction by the pre-processing roller 211A and the pair of alignment plates 271A are ready to start the shift operation. As described above, the alignment plate on the upstream side in the shift direction is called the first shift section, and the alignment plate on the downstream side in the shift direction is called the second shift section.

[0256] (1) Move the first shift section and the second shift section toward each other to first grip both edges of the sheet in the sheet width direction, and then move the first shift section and the second shift section simultaneously in the shift direction to shift the sheet. (2) With the second shift section stopped, move the first shift section in the shift direction and abut the sheet against the second shift section. Then move the first shift section and the second shift section simultaneously in the shift direction to shift the sheet. (3) Move both the first shift section and the second shift section in the shift direction, with the movement speed of the first shift section being faster than the movement speed of the second shift section. Before the shift operation is completed, the sheet is gripped by the first shift section and the sheet is shifted in that state. (4) With the first shift section stopped, move the second shift section toward the first shift section and bring it into contact with the edge of the sheet on the second shift section side. (5) With the first shift unit stopped, the second shift unit is moved toward the first shift unit to grip both edges of the seat, and in that state, the first shift unit and the second shift unit are moved toward the shift unit to shift the seat.

[0257] Furthermore, in the embodiments described above, the shift direction is in both directions, from the rear to the front and from the front to the rear, and both of the pair of alignment plates 271A (271) move in the shift direction. However, one of the alignment plates 271A may be fixed in place and the other may move toward the fixed alignment plate. In that case, the moving alignment plate becomes the first shift unit, and the drive motor for moving the first shift unit becomes the first drive unit. In this case, during stapling, the sheet width is aligned by moving the sheet toward the fixed alignment plate using the movable alignment plate which is the first shift unit, and the position thus positioned becomes the stapling position. Also, in the first and second shift discharge processes, the sheet is shifted to one side and discharged to the loading tray 300 by moving the sheet toward the fixed alignment plate using the movable alignment plate which is the first shift unit. Then, the sheets discharged to the loading tray 300 can be sorted by combining the sheets discharged with one-sided shifts and the sheets discharged straight.

[0258] In the embodiments described above, the sheet processing apparatus 200 is arranged within the internal space 130 of the image forming apparatus 100. However, the sheet processing apparatus of the present invention may be configured, for example, to be mounted on the side of the image forming apparatus. Furthermore, the sheet processing apparatus may be controlled by a control unit provided in the image forming apparatus.

[0259] Furthermore, the disclosure of this embodiment includes the following configuration. (Composition 1) A first conveying unit that conveys the sheet in a first conveying direction, A mounting section for temporarily placing sheets that have been transported in the first transport direction by the first transport section, A second conveying unit conveys the sheet on the aforementioned storage unit, which has been conveyed by the first conveying unit, in a second conveying direction opposite to the first conveying direction. A stopper portion against which the downstream edge of the sheet conveyed in the second conveying direction by the second conveying portion abuts, A first shift unit moves the sheet that has been conveyed in the first conveying direction by the first conveying unit in the shift direction by moving it in a shift direction intersecting the first conveying direction while in contact with one edge of the sheet that has been conveyed in the first conveying direction along the first conveying direction, A first drive unit that drives the first shift unit to move the first shift unit in the shift direction, A processing unit that performs a binding process on a plurality of sheets that have been transported in the second transport direction by the second transport unit so that their downstream edge in the second transport direction abuts against the abutment unit, and then moved in the shift direction by the first shift unit to be positioned at the binding position, A loading section is located downstream of the aforementioned loading section in the first transport direction, and loads sheets that have been transported in the first transport direction by the first transport section, A discharge unit that discharges the sheets conveyed in the first conveying direction by the first conveying unit to the loading unit, Equipped with, After the sheet is conveyed in the first conveying direction by the first conveying unit, the sheet conveyed in the first conveying direction by the first conveying unit is conveyed in the second conveying direction by the second conveying unit on the aforementioned storage unit so that the downstream edge of the sheet in the second conveying direction abuts against the abutment unit, and the first shift unit is driven by the first drive unit to move the sheet abutted against the abutment unit in the shift direction and position it at the binding position, and so on, the binding process is performed by the processing unit on a plurality of sheets positioned at the binding position, and the plurality of bound sheets are discharged to the storage unit by the discharge unit, binding and discharge process, A sheet processing apparatus capable of performing a switchbackless shift discharge process, in which, after the sheet is conveyed in the first conveying direction by the first conveying unit, the sheet conveyed in the first conveying direction by the first conveying unit is driven by the first drive unit to move the sheet conveyed in the first conveying direction by the first conveying unit in the shift direction, without the sheet conveyed in the first conveying direction by the first conveying unit being conveyed in the second conveying direction by the second conveying unit, and the sheet moved in the shift direction by the first shift unit is discharged to the loading unit by the discharge unit. (Configuration 2) Furthermore, the sheet processing apparatus according to Configuration 1 is capable of performing a switchback shift discharge process, in which, after the sheet is conveyed in the first conveying direction by the first conveying unit, the sheet conveyed in the first conveying direction by the first conveying unit is conveyed in the second conveying direction by the second conveying unit on the aforementioned storage unit so that the downstream edge of the sheet in the second conveying direction abuts against the abutment unit, the first shift unit drives the first shift unit to move the sheet conveyed in the first conveying direction by the first conveying unit in the shift direction, and the sheet moved in the shift direction by the first shift unit is discharged to the storage unit by the discharge unit without performing the binding process by the processing unit. (Composition 3) The discharge unit is a pair of discharge rotating bodies, at least one of which rotates while gripping the sheet that has been conveyed in the first conveying direction by the first conveying unit. The system further includes a discharge rotating body moving member that moves at least one of the pair of discharge rotating bodies from a clamping position where the pair of discharge rotating bodies clamp a sheet conveyed in the first conveying direction by the first conveying unit to a separated position where the pair of discharge rotating bodies are separated from each other. The sheet processing apparatus according to configuration 2, wherein, in the switchbackless shift discharge processing and the switchback shift discharge processing, the sheet conveyed in the first conveying direction by the first conveying unit is located between the pair of discharge rotating bodies, and the pair of discharge rotating bodies are separated by the discharge rotating body moving member, and the sheet is moved in the shift direction by the first shifting unit. (Composition 4) The discharge unit is a pair of discharge rotating bodies, at least one of which rotates while gripping the sheet that has been conveyed in the first conveying direction by the first conveying unit. The discharge rotating body further comprises a discharge rotating body nip pressure switching mechanism that switches the nip pressure used by the pair of discharge rotating bodies to grip the sheet conveyed in the first conveying direction by the first conveying unit between a first nip pressure and a second nip pressure weaker than the first nip pressure. The sheet processing apparatus according to configuration 2, wherein, in the switchbackless shift discharge processing and the switchback shift discharge processing, the sheet conveyed in the first conveying direction by the first conveying unit is between the pair of discharge rotating bodies, and the nip pressure of the pair of discharge rotating bodies is set to the second nip pressure by the discharge rotating body nip pressure switching mechanism, and the sheet is moved in the shift direction by the first shifting unit. (Composition 5) The first conveying unit is a pair of conveying rotating bodies, at least one of which rotates while holding the sheet. The system further includes a conveying rotating body moving member that moves at least one of the pair of conveying rotating bodies from a clamping position where the sheet is clamped between the pair of conveying rotating bodies to a separated position where the pair of conveying rotating bodies are separated from each other. A sheet processing apparatus according to any one of configurations 1 to 4, wherein, in the switchbackless shift discharge process, the sheet is located between the pair of conveying rotating bodies, and the pair of conveying rotating bodies are separated by the conveying rotating body moving member, and the sheet is moved in the shift direction by the first shift unit. (Composition 6) The first conveying unit is a pair of conveying rotating bodies, at least one of which rotates while holding the sheet. The system further includes a conveying rotating body nip pressure switching mechanism that switches the nip pressure used to grip the sheet between the pair of conveying rotating bodies between a first nip pressure and a second nip pressure weaker than the first nip pressure. A sheet processing apparatus according to any one of configurations 1 to 4, wherein, in the switchbackless shift discharge process, the sheet is located between the pair of conveying rotating bodies, and the nip pressure of the pair of conveying rotating bodies is set to the second nip pressure by the conveying rotating body nip pressure switching mechanism, and the sheet is moved in the shift direction by the first shift unit. (Composition 7) A sheet processing apparatus according to any one of configurations 2 to 4, wherein, when a sheet conveyed in the first conveying direction by the first conveying unit is shifted in the shift direction and discharged without performing the binding process, the switchback-less shift discharge process is performed on a first sheet whose length in the first conveying direction is a first length, and the switchback-shift discharge process is performed on a second sheet whose length in the first conveying direction is a second length that is longer than the first length. (Composition 8) The sheet processing apparatus according to configuration 3 or 4, wherein the first shift section extends from the upstream side to the downstream side in the first conveying direction with respect to the pair of discharge rotating bodies. (Composition 9) The sheet processing apparatus according to configuration 8, wherein the first shift section is provided downstream in the first conveying direction from the nip position where the sheet is held by the pair of discharge rotating bodies, and vertically above the nip position, and has a curl-holding section that holds down the leading edge of the sheet conveyed in the first conveying direction by the upwardly curled first conveying section. (Composition 10) The sheet processing apparatus according to configuration 8 or 9, wherein the first shift section is provided downstream in the first conveying direction from the nip position where the sheet is held by the pair of discharge rotating bodies, and vertically below the nip position, and has a support section that supports the sheet conveyed in the first conveying direction by the first conveying section from below. (Composition 11) A second shift unit that is movable in the shift direction while in contact with the other edge of the sheet that has been conveyed in the first conveying direction by the first conveying unit, along the first conveying direction, The system further comprises a second drive unit that drives the second shift unit to move the second shift unit in the shift direction, A sheet processing apparatus according to any one of configurations 1 to 10, wherein the first shift unit and the second shift unit move the sheet conveyed in the first conveying direction by the first conveying unit in the shift direction while sandwiching it from both sides in the shift direction. [Explanation of Symbols]

[0260] 200, 200A... Sheet processing equipment 210, 210A... Transport path 211, 211A, 212A... Rollers before processing 212... Conveyor belt 220... Processing tray 230... Discharge Roller 230A... Upper discharge roller 230B... Lower discharge roller 240... Scraping section 240a... scraping belt 240A... raking paddle 250, 250A... Rear end drop member 260... Discharge belt 270, 270A...Matching section 271, 271A...Matching plate 280...Return parts 290...Rear end restricting member 300... Loading tray 310... Standing Face 320...Seat retaining belt 400 staple unit 600... Drive configuration 2703... Curl-holding part 2704...Support part MT3... Lifting motor MT16···F-side matching plate moving motor MT17···R-side matching plate moving motor

Claims

1. A first conveying unit that conveys the sheet in a first conveying direction, A mounting section for placing the sheet transported by the first transport section, The abutment portion against which the upstream end of the sheet on the mounting portion in the first transport direction abuts, A second conveying unit that conveys the sheet in a second conveying direction such that the upstream end of the sheet on the mounting unit in the first conveying direction is toward the abutment unit, A shift unit moves the sheet conveyed by the first conveying unit in the shift direction by contacting one edge of the sheet along the first conveying direction and moving in a shift direction intersecting the first conveying direction, A drive unit that drives the shift unit to move the shift unit in the shift direction, A processing unit that performs a binding process on a plurality of sheets that have been transported in the second transport direction by the second transport unit so that their downstream ends in the second transport direction abut against the abutment unit, and then moved in the shift direction by the shift unit to be positioned at the binding position, A loading section is located downstream of the aforementioned loading section in the first transport direction and loads the sheets transported by the first transport section, A pair of discharge rollers having an upper discharge roller and a lower discharge roller, configured to discharge the sheets conveyed by the first conveying unit to the loading unit, An upper discharge roller moving unit moves the upper discharge roller between a clamping position in which the sheet is clamped between the upper discharge roller and the lower discharge roller, a first separation position in which the upper discharge roller is separated from the lower discharge roller, and a second separation position in which the upper discharge roller is located in the vertical direction between the clamping position and the first separation position. A sensor that detects the sheet, A control unit configured to control the first transport unit, the second transport unit, the drive unit, the discharge roller pair, and the upper discharge roller moving unit based on the signal from the sensor, Equipped with, The control unit, A binding and discharge process is performed by repeatedly moving the sheets that have been transported by the first transport unit in the second transport direction on the aforementioned storage unit by the second transport unit so that the downstream end of the sheet in the second transport direction abuts against the abutment unit, and by driving the drive unit so that the sheet abutted against the abutment unit is moved in the shift direction by the shift unit to be positioned at the binding position, thereby performing the binding process on a plurality of sheets positioned at the binding position by the processing unit, and discharging the plurality of bound sheets to the loading unit by the discharge roller pair, A switchbackless shift discharge process is performed in which, with the upper discharge roller in the first separation position, the sheet is conveyed in the first conveying direction until the downstream end of the sheet in the first conveying direction passes between the upper discharge roller and the lower discharge roller, then the upper discharge roller is moved from the first separation position toward the second separation position to push down the sheet, then with the upper discharge roller in the second separation position, the drive unit is driven to shift the sheet in the shift direction without the second conveying unit conveying the sheet toward the second conveying direction, and then the upper discharge roller is moved toward the clamping position to discharge the sheet to the loading unit by the pair of discharge rollers. A sheet processing device capable of selectively executing [a specific action].

2. The sheet processing apparatus according to claim 1, wherein the control unit further conveys the sheet in the first conveying direction by the first conveying unit, then conveys the sheet conveyed in the first conveying direction by the first conveying unit in the second conveying direction by the second conveying unit on the aforementioned loading unit so that the downstream end of the sheet in the second conveying direction abuts against the abutment unit, and drives the shift unit to move the sheet conveyed in the first conveying direction by the first conveying unit in the shift direction by the shift unit, and without performing the binding process by the processing unit, the sheet moved in the shift direction by the shift unit is discharged to the loading unit by the discharge roller pair.

3. The sheet processing apparatus according to claim 2, wherein when the control unit shifts and discharges a sheet conveyed by the first conveying unit in the shift direction without performing the binding process, it performs the switchback-less shift discharge process for a first sheet whose length in the first conveying direction is a first length, and it performs the switchback-shift discharge process for a second sheet whose length in the first conveying direction is a second length that is longer than the first length.

4. The sheet processing apparatus according to claim 1, wherein the shift section extends from the upstream side to the downstream side in the first conveying direction with respect to the discharge roller pair.

5. The sheet processing apparatus according to claim 4, wherein the shift section is provided downstream in the first conveying direction from the nip position where the sheet is held between the discharge roller pair, and vertically below the nip position, and has a support section that supports the sheet conveyed by the first conveying section from below.

6. Another shift unit that is movable in the shift direction while in contact with the other edge of the sheet conveyed by the first conveying unit along the first conveying direction, The system further comprises another drive unit for driving the other shift unit to move the other shift unit in the shift direction, The sheet processing apparatus according to claim 1, wherein, in the switchbackless shift discharge process, the shift unit and the other shift unit move the sheet conveyed by the first conveying unit in the shift direction while sandwiching it from both sides in the shift direction.

7. An image forming unit that forms an image on a sheet, A first transport unit transports the sheet on which the image has been formed by the image forming unit in a first transport direction, A mounting section for placing the sheet transported by the first transport section, The abutment portion against which the upstream end of the sheet on the mounting portion in the first transport direction abuts, A second conveying unit that conveys the sheet in a second conveying direction such that the upstream end of the sheet on the mounting unit in the first conveying direction is toward the abutment unit, A shift unit moves the sheet conveyed by the first conveying unit in the shift direction by contacting one edge of the sheet along the first conveying direction and moving in a shift direction intersecting the first conveying direction, A drive unit that drives the shift unit to move the shift unit in the shift direction, A processing unit that performs a binding process on a plurality of sheets that have been transported in the second transport direction by the second transport unit so that their downstream ends in the second transport direction abut against the abutment unit, and then moved in the shift direction by the shift unit to be positioned at the binding position, A loading section is located downstream of the loading section in the first transport direction and loads the sheets transported by the first transport section; and a pair of discharge rollers has an upper discharge roller and a lower discharge roller and is configured to discharge the sheets transported by the first transport section to the loading section. An upper discharge roller moving unit moves the upper discharge roller between a clamping position in which the sheet is clamped between the upper discharge roller and the lower discharge roller, a first separation position in which the upper discharge roller is separated from the lower discharge roller, and a second separation position in which the upper discharge roller is located in the vertical direction between the clamping position and the first separation position. A sensor that detects the sheet, A control unit configured to control the first transport unit, the second transport unit, the drive unit, the discharge roller pair, and the upper discharge roller moving unit based on the signal from the sensor, Equipped with, The control unit, A binding and discharge process is performed by repeatedly moving the sheets that have been transported by the first transport unit in the second transport direction on the aforementioned storage unit by the second transport unit so that the downstream end of the sheet in the second transport direction abuts against the abutment unit, and by driving the drive unit so that the sheet abutted against the abutment unit is moved in the shift direction by the shift unit to be positioned at the binding position, thereby performing the binding process on a plurality of sheets positioned at the binding position by the processing unit, and discharging the plurality of bound sheets to the loading unit by the discharge roller pair, A switchbackless shift discharge process is performed in which, with the upper discharge roller in the first separation position, the sheet is conveyed in the first conveying direction until the downstream end of the sheet in the first conveying direction passes between the upper discharge roller and the lower discharge roller, then the upper discharge roller is moved from the first separation position toward the second separation position to push down the sheet, then with the upper discharge roller in the second separation position, the drive unit is driven to shift the sheet in the shift direction without the second conveying unit conveying the sheet toward the second conveying direction, and then the upper discharge roller is moved toward the clamping position to discharge the sheet to the loading unit by the pair of discharge rollers. An image forming system capable of selectively performing certain actions.

Images