Sheet loading device and image forming system

Abstract

To reduce impact noise when an upper surface of a sheet is pressed down by a sheet pressing paddle 320.SOLUTION: A rotation shaft 3201 is located on a lower surface side of a sheet being discharged by an upper discharge roller 230A and a lower discharge roller 230B. A sheet pressing paddle 320 rotates about a rotation shaft 3201 to press down an upper surface of the sheet discharged onto a loading tray with a paddle part 3203. A take-in motor rotates the sheet pressing paddle 320 from a state where the paddle presses the sheet loaded on the loading tray, temporarily stops rotating until the upper surface of the next sheet to be discharged by the upper discharge roller 230A and the lower discharge roller 230B is pressed down, by starting the rotation again, the sheet pressing paddle 320 is driven to press the upper surface of the next sheet discharged onto the loading tray at a rotation speed slower than the fastest rotation speed of the sheet pressing paddle 320 before temporarily stopped.SELECTED DRAWING: Figure 47

Description

[Technical field]

[0001] The present invention relates to a sheet stacking device for stacking sheets, and an image forming system including the sheet stacking device. [Background technology]

[0002] Patent Document 1 describes a configuration having a pressing member that presses down the upper surfaces of already-stacked sheets after the sheets are discharged onto the stacking tray. In the configuration described in Patent Document 1, the pressing member rotates around a rotation axis to press down the upper surfaces of the sheets on the stacking tray. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-30603 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the case of the configuration described in the patent document, the next sheet is discharged while the sheets already on the stack tray are being held down by the holding member, and before the leading edge of the next sheet comes into contact with the sheet discharged onto the stack tray, the holding member must be rotated to hold down the top surface of the discharged sheet, which may result in the holding member coming into forcefully contact with the top surface of the sheet and generating a collision noise. [Means for solving the problem]

[0005] One aspect of the present invention is a sheet stacking device comprising: a loading section for loading sheets; a discharge section for discharging sheets onto the loading section; a pressing member having a rotating shaft located on the underside of the sheet being discharged by the discharge section, a fixed section fixed to the rotating shaft, and an elastic abutment section provided on the fixed section, and rotating around the rotating shaft to press down the upper surface of the sheet discharged to the loading section with the abutment section; and a drive section that drives the pressing member to rotate from a state in which it is holding down a sheet loaded on the loading section, stop the rotation temporarily before pressing down the upper surface of the next sheet discharged by the discharge section, and start the rotation again so that the pressing member presses down the upper surface of the next sheet discharged to the loading section at a rotational speed slower than the fastest rotational speed of the pressing member before it was stopped.

[0006] One aspect of the present invention is a sheet stacking device comprising a loading section for loading sheets, a discharge section for discharging sheets onto the loading section, a pressing member having a rotating shaft located on the underside of the sheet being discharged by the discharge section, a fixed section fixed to the rotating shaft, and an elastic abutment section provided on the fixed section, and rotating around the rotating shaft to press the upper surface of the sheet discharged to the loading section with the abutment section, and a drive section that rotates the pressing member from a state in which it is pressing down on the sheets loaded on the loading section, decelerates the rotational speed from a first speed to a second speed before pressing the upper surface of the next sheet discharged by the discharge section, and then drives the pressing member to press the upper surface of the next sheet discharged to the loading section. Effect of the Invention

[0007] According to the present invention, it is possible to reduce the impact noise generated when the pressing member presses down on the upper surface of the sheet. [Brief description of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view showing a schematic configuration of an image forming system according to a first embodiment. [Diagram 2] 1 is a schematic cross-sectional view of a sheet processing apparatus according to a first embodiment. [Diagram 3] 1 is a schematic perspective view showing a sheet processing apparatus according to a first embodiment with an upper cover removed; [Figure 4] 1A is a diagram showing an alignment plate on a processing tray as viewed from the width direction, FIG. 1B is a diagram showing the alignment plate as viewed from the downstream side in the sheet conveying direction, and FIG. [Diagram 5] FIG. 2A is a perspective view of the periphery of a sheet pressing paddle according to the first embodiment, and FIG. 2B is a perspective view of the sheet pressing paddle. [Figure 6] 1A is a perspective view of the periphery of a processing tray in a home position of a sheet processing apparatus according to a first embodiment, and FIG. 1B is a schematic cross-sectional view of the sheet processing apparatus. [Figure 7] 5A is a diagram showing a state of a discharge roller, a state of a pick-up paddle, and a state of a trailing end drop-off member in a home position of the sheet processing apparatus according to the first embodiment, as viewed from the width direction. [Figure 8] FIG. 4 is a perspective view showing an engagement relationship between a trailing end dropping member and a sweeping paddle according to the first embodiment. [Figure 9] 1A is a perspective view of the periphery of a processing tray when the sheet processing apparatus according to the first embodiment discharges a sheet, and FIG. 1B is a schematic cross-sectional view of the sheet processing apparatus. [Figure 10] 5A is a diagram showing a state of a discharge roller, a state of a pick-up paddle, and a state of a trailing end drop-off member when a sheet is discharged from the sheet processing apparatus according to the first embodiment, as viewed from the width direction. [Figure 11] 1A is a perspective view of the periphery of a processing tray when the sheet processing apparatus according to the first embodiment picks up a sheet, and FIG. 1B is a schematic cross-sectional view of the sheet processing apparatus. [Figure 12] 5A is a diagram showing a state of a discharge roller, a state of a pick-up paddle, and a state of a trailing end drop-off member when the sheet processing apparatus according to the first embodiment picks up a sheet, as viewed from the width direction. [Figure 13] 4 is a table showing the correspondence between each motor and each component of the sheet processing apparatus according to the first embodiment. [Figure 14]FIG. 2 is a block diagram showing a control configuration of the sheet processing apparatus according to the first embodiment. [Figure 15] 5 is a flowchart showing an example of a control flow of the sheet processing apparatus according to the first embodiment. [Figure 16] 1A is a schematic diagram of a main part of a sheet processing apparatus at a home position of a first shift discharge process according to a first embodiment, as viewed from above, and FIG. 1B is a schematic cross-sectional view of the configuration. [Figure 17] 1A is a schematic diagram of a main part of a sheet processing apparatus when receiving a sheet in a first shift discharge process according to a first embodiment, and FIG. 1B is a schematic cross-sectional view of the configuration. [Figure 18] 1A is a schematic diagram of a main part of a sheet processing apparatus when an upper discharge roller is lowered in a first shift discharge process according to a first embodiment, and FIG. 1B is a schematic cross-sectional view of the configuration. [Figure 19] 1A is a schematic diagram of a main part of a sheet processing apparatus when conveyance is stopped in a first shift discharge process according to a first embodiment, and FIG. 1B is a schematic cross-sectional view of the configuration. [Figure 20] 1A is a schematic diagram of a main part of the sheet processing apparatus when an alignment plate moves in a first shift discharge process according to a first embodiment, and FIG. 1B is a schematic cross-sectional view of the configuration. [Figure 21] 1A is a schematic diagram of a main part of the sheet processing apparatus when a sheet is shifted by an alignment plate in a first shift discharge process according to a first embodiment, and FIG. 1B is a schematic cross-sectional view of the configuration. [Figure 22] 1A is a schematic diagram of a main part of a sheet processing apparatus when a first shift discharge process of a sheet is completed, and FIG. 1B is a schematic cross-sectional view of the configuration thereof; [Figure 23] 1A is a schematic diagram of a main part of the sheet processing apparatus when an alignment plate is retracted in a first shift discharge process according to a first embodiment, and FIG. 1B is a schematic cross-sectional view of the configuration. [Figure 24] 1A is a schematic diagram of a main part of a sheet processing apparatus when discharging a sheet in a first shift discharging process according to a first embodiment, as viewed from above, and FIG. 1B is a schematic cross-sectional view of the configuration. [Diagram 25]1A is a schematic diagram of a main part of a sheet processing apparatus when sheet discharge in a first shift discharge process according to a first embodiment is completed, and FIG. 1B is a schematic cross-sectional view of the configuration thereof. [Figure 26] 1A is a schematic diagram of a main part of the sheet processing apparatus when the leading edge of the sheet in the second shift discharge process has passed the discharge rollers according to the first embodiment, and FIG. [Figure 27] 1A is a schematic diagram of a main part of the sheet processing apparatus in a state in which the rear end of the sheet in the second shift discharge process has passed through the pre-processing rollers according to the first embodiment, and FIG. [Figure 28] 1A is a schematic diagram of a main part of the sheet processing apparatus when a sheet is picked up in a second shift discharge process according to a first embodiment, and FIG. 1B is a schematic cross-sectional view of the configuration. [Figure 29] 1A is a schematic diagram of a main part of the sheet processing apparatus when a returning member is lowered in a second shift discharge process according to a first embodiment, and FIG. 1B is a schematic cross-sectional view of the configuration. [Diagram 30] 1A is a schematic diagram of the main parts of the sheet processing device when the trailing end dropping member, the pick-up paddle, and the returning member are raised in the second shift discharge process according to the first embodiment, and FIG. [Diagram 31] 1A is a schematic diagram of a main part of the sheet processing apparatus when a sheet is shifted by an alignment plate in a second shift discharge process according to a first embodiment, and FIG. 1B is a schematic cross-sectional view of the configuration. [Diagram 32] 1A is a schematic diagram of a main part of the sheet processing apparatus when shifting of sheets in a second shift discharge process according to a first embodiment is completed, and FIG. 1B is a schematic cross-sectional view of the configuration. [Diagram 33] 1A is a schematic diagram of a main part of the sheet processing apparatus when an alignment plate is retracted in a second shift discharge process according to a first embodiment, and FIG. 1B is a schematic cross-sectional view of the configuration. [Diagram 34] 1A is a schematic diagram of a main part of the sheet processing apparatus when discharging a sheet in a second shift discharging process according to a first embodiment, as viewed from above, and FIG. 1B is a schematic cross-sectional view of the configuration. [Diagram 35]1A is a schematic diagram of a main part of the sheet processing apparatus when sheet discharge in the second shift discharge process according to the first embodiment is completed, and FIG. 1B is a schematic cross-sectional view of the configuration. [Diagram 36] 3 is a schematic cross-sectional view of the sheet pressing paddle and its surroundings, showing a home position of the sheet pressing paddle according to the first embodiment; FIG. [Figure 37] 3 is a schematic cross-sectional view of the periphery of the sheet pressing paddle, showing a sheet receiving position of the sheet pressing paddle according to the first embodiment; FIG. [Figure 38] 4 is a schematic cross-sectional view of the sheet pressing paddle and its surroundings, illustrating a state in which the sheet pressing paddle according to the first embodiment presses down a first sheet on a stack tray. FIG. [Figure 39] 4 is a schematic cross-sectional view of the sheet pressing paddle and its surroundings, illustrating a state in which the sheet pressing paddle according to the first embodiment is pressing a first sheet on a stack tray and a subsequent second sheet is being discharged. FIG. [Diagram 40] 4 is a schematic cross-sectional view of the sheet pressing paddle and its surroundings, illustrating a state in which the sheet pressing paddle according to the first embodiment starts to rotate; FIG. [Diagram 41] 4 is a schematic cross-sectional view of the periphery of the sheet pressure paddle, illustrating a state in which the rotation of the sheet pressure paddle according to the first embodiment is accelerating; FIG. [Diagram 42] 4 is a schematic cross-sectional view of the sheet pressing paddle and its surroundings, illustrating a state in which the rotation of the sheet pressing paddle according to the first embodiment is temporarily stopped; FIG. [Diagram 43] 4 is a schematic cross-sectional view of the sheet pressing paddle and its surroundings, illustrating a state in which the sheet pressing paddle according to the first embodiment presses down a second sheet on the stack tray. FIG. [Diagram 44] FIG. 11 is a schematic cross-sectional view of the area around the sheet pressure paddle, showing (a) a state in which the sheet pressure paddle in the first embodiment is rotating, (b) a state in which the tip of the sheet pressure paddle is elastically deflected downstream in the direction of rotation when the rotation of the sheet pressure paddle is temporarily stopped, and (c) a state in which the tip of the sheet pressure paddle is elastically deflected upstream in the direction of rotation. [Diagram 45]FIG. 4A is a schematic diagram showing the operation of the sheet pressing paddle according to the first embodiment when detecting the home position, and FIG. [Figure 46] FIG. 4A is a schematic diagram showing the operation of a sheet pressing paddle according to the first embodiment when the sheet pressing paddle moves from a home position to a sheet pressing position, and FIG. [Figure 47] FIG. 4A is a schematic diagram showing an operation of a sheet pressing paddle according to the first embodiment when the sheet pressing paddle moves from a sheet pressing position to a sheet pressing position for a next sheet, and FIG. [Figure 48] 11A is a schematic diagram showing the operation of a sheet pressing paddle according to a second embodiment when the sheet pressing paddle moves from a home position to a sheet pressing position, and FIG. [Figure 49] 13A is a schematic diagram showing an operation of a sheet pressing paddle according to a second embodiment when the sheet pressing paddle moves from a sheet pressing position to a sheet pressing position for a next sheet, and FIG. [Figure 50] FIG. 11 is a cross-sectional view showing a schematic configuration of an image forming system according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] <First embodiment> The first embodiment will be described with reference to Figures 1 to 47. First, the schematic configuration of an image forming system according to the present embodiment will be described with reference to Figure 1.

[0010] [Image formation system] 1 is a cross-sectional view showing a schematic configuration of an image forming system according to the present embodiment. The image forming system 1000 includes an image forming apparatus 100 and a sheet processing apparatus 200. The image forming apparatus 100 may be a copier, printer, facsimile, or a multifunction machine having a plurality of these functions, and forms an image on a sheet such as paper or a plastic sheet. In this embodiment, the image forming apparatus 100 is an electrophotographic printer, and a sheet on which a toner image has been formed is discharged from a discharge port 101. The image forming apparatus 100 may be an inkjet image forming apparatus.

[0011] The image forming apparatus 100 of this embodiment includes an image forming apparatus main body 110 and an image reading device 120 arranged above the image forming apparatus main body 110. In the image forming apparatus main body 110, a toner image is formed on a sheet in an image forming section 103. The image forming section 103 of this embodiment forms a full-color toner image using toner of four colors, yellow (y), magenta (m), cyan (c), and black (k). For this reason, the image forming section 103 has a plurality of image forming stations that form toner images of each color. The configuration of the image forming stations of each color is the same except that the colors of the toner are different.

[0012] In the image forming station for each color, the surface of the photosensitive drum 10 is charged by a charging member 11 and exposed to light by an exposure device (not shown), thereby forming an electrostatic latent image on the photosensitive drum 10. This electrostatic latent image is then developed into a toner image by a developing device 12 using a developer. The toner image formed on the photosensitive drum 10 is primarily transferred onto an intermediate transfer belt 14 by a primary transfer roller 13. Residual toner remaining on the photosensitive drum 10 after the primary transfer is removed by a drum cleaner 15.

[0013] This cycle of charging, exposing, developing, primary transfer and drum cleaning is repeated in the same way at each image forming station, and the yellow, magenta, cyan and black toner images are transferred in sequence onto the intermediate transfer belt 14, forming a full-color toner image.

[0014] Meanwhile, the image forming apparatus 100 has a plurality of cassettes 20 for storing sheets. The sheets stored in each cassette 20 are conveyed to a sheet conveying path 22 by the rotation of a feed roller 21, and reach a registration roller 23. The registration roller 23 feeds the sheet to a secondary transfer section 17 formed by the intermediate transfer belt 14 and a secondary transfer roller 16 in synchronization with the toner image on the intermediate transfer belt 14. The multi-color toner images formed on the intermediate transfer belt 14 are secondarily transferred collectively onto the sheet in the secondary transfer section 17. Residual toner and paper powder remaining on the intermediate transfer belt 14 after the secondary transfer are removed by a belt cleaner 18.

[0015] The sheet that has passed through the secondary transfer unit 17 is transported to the fixing device 30, which serves as an image heating device. The fixing device 30 has a heating roller 31 and a pressure roller 32, which form a heating nip portion that sandwiches and transports the sheet between them. The sheet transported to the fixing device 30 is heated and pressurized in the heating nip portion, and the unfixed toner image is fixed onto the sheet. The sheet with the fixed toner image is transported through the discharge transport path 24 and is discharged to the outside of the machine from a discharge port 101 by discharge rollers 25, completing a series of image forming operations.

[0016] As described above, the image forming apparatus 100 of this embodiment includes the image forming apparatus main body 110 and the image reading device 120. The image reading device 120 reads an image on an original placed on the platen glass 122 by the image reading unit 121, and sends a read image signal to the image forming apparatus main body 110. In addition, an automatic document feeder (ADF) 123 that transports the original to the image reading unit 121 is disposed above the image reading device 120. The image reading device 120 can also read an image on an original fed by the document feeding device 123.

[0017] The image forming apparatus main body 110 has a first housing section 111 in which the image forming section 103 and the like are arranged, and a second housing section 112 in which the discharge conveying path 24 and the discharge rollers 25 are arranged, and the second housing section 112 is provided above the first housing section 111. The image reading device 120 is provided above the second housing section 112. In addition, the second housing section 112 is provided with an operation panel (not shown) so that a user can input instructions (printing conditions, mode settings, etc.) to the image forming apparatus 100 and the sheet processing apparatus 200.

[0018] In this embodiment, with this configuration, there is an internal space 130 surrounded by the first housing 111, the second housing 112, and the image reading device 120. The image forming apparatus body 110 is configured so that a sheet is discharged from the discharge port 101 into the internal space 130. A sheet processing device 200 and the like are detachably attached to the internal space 130. In this embodiment, the image forming system 1000 is configured by installing the sheet processing device 200, but other devices that perform sheet processing may also be installed.

[0019] The sheet processing apparatus 200 is connected to the discharge port 101 and receives the sheets discharged from the discharge port 101. Then, as will be described in detail later, it is possible to perform predetermined processing such as binding processing on the sheets.

[0020] [Sheet processing device] The configuration of the sheet processing apparatus 200 of this embodiment will be described with reference to Figs. 2 to 12(c). The sheet processing apparatus 200 of this embodiment corresponds to a sheet stacking apparatus. First, the overall configuration of the sheet processing apparatus 200 will be described with reference to Figs. 2 and 3. In the following description, the front side (front (F) side) is one side (the near side in Fig. 2, the near right side in Fig. 3) in the sheet width direction perpendicular to the sheet conveying direction, and is the side where an operator operates the image forming system 1000, for example, the side where an operation panel is installed. The rear side (rear (R) side) is the opposite side to the front side, and is the other side (the far side in Fig. 2, the far left side in Fig. 3) in the sheet width direction.

[0021] [Overall configuration of sheet processing device] The sheet processing apparatus 200 includes a conveying path 210A, pre-processing rollers 211A and 212A as a first conveying section, a processing tray 220 as a placement section, an upper discharge roller (nip member) 230A and a lower discharge roller 230B as a pair of discharge rotating bodies (discharge section), a pick-up paddle 240A as a second conveying section, a trailing end drop member 250A as a sheet drop section, an alignment section 270A as a first and second shift section, a return member 280, a trailing end regulating member 290 as a striking section, a stacking tray 300 as a stacking section, and a sheet pressing paddle 320 as a pressing member. In this embodiment, the sheet pressing paddle 320 also functions as a discharged sheet pick-up paddle as a pick-up section. The sheet received from the image forming apparatus 100 is conveyed to the conveying path 210A.

[0022] The sheet conveyed from the conveying path 210A is directly discharged to the stacking tray 300 or placed on the processing tray 220 depending on the mode of processing the sheet. Note that direct discharge to the stacking tray 300 means that the sheet is discharged to the stacking tray 300 without being conveyed backward to a position on the processing tray 220 where stapling (binding) can be performed. In other words, the sheet processing device 200 has a mode in which the sheet stapled by the staple unit 400 is discharged to the stacking tray 300, and a mode in which the sheet is discharged to the stacking tray 300 without stapling by the staple unit 400. In this embodiment, the sheet can be aligned by a pair of alignment plates 271A of the alignment section 270A without being placed on the processing tray 220. Also, the sheet can be aligned on the processing tray 220, and the staple unit 400 can staple the sheet placed on the processing tray 220. Furthermore, the sheet or sheet stack placed on the processing tray 220 can be discharged onto the stacking tray 300 by a pair of discharge rotating bodies, such as an upper discharge roller 230A and a lower discharge roller 230B. The configuration of each section will be described in detail below.

[0023] [Transport path] The conveying path 210A is a path for conveying a sheet in a first conveying direction (a predetermined direction), and includes an upper guide 2101 for guiding the upper surface of the conveyed sheet, and a lower guide 2102 for guiding the lower surface of the sheet. In the conveying path 210A, pre-processing rollers 211A and 212A and upstream rollers (entrance rollers) 213a and 213b are arranged as a first conveying section (a pair of conveying rotating bodies). These are arranged in pairs so as to be spaced apart in the sheet width direction (arrow γ direction in FIG. 3) intersecting with the sheet conveying direction (first conveying direction, arrow β direction in FIG. 2 (left-right direction)).

[0024] The pre-processing rollers 211A and 212A are a conveying section, a first conveying section, and a pair of conveying rotors that convey a sheet in a predetermined direction, and at least one of them rotates while sandwiching a sheet. The upstream rollers 213a and 213b are at least one of them rotates while sandwiching a sheet. The upstream rollers 213a and 213b are disposed at the entrance of the sheet processing apparatus 200, and receive the sheet conveyed from the upstream side of the sheet processing apparatus 200 and convey it to the conveying path 210A. Then, the sheet that has passed through the conveying path 210A reaches the pre-processing rollers 211A and 212A.

[0025] The pre-processing rollers 211A and 212A form a pre-processing nip portion 211a capable of nipping and transporting a sheet. The pre-processing nip portion 211a nips the sheet and transports it in the first transport direction, and the sheet is discharged from the transport path 210A. As described later, the pre-processing rollers 211A and 212A can be brought into contact with or separated from each other, or the nip pressure can be changed.

[0026] [Processing tray] The processing tray 220 as a placement unit is disposed downstream in the sheet conveying direction (first conveying direction) of the conveying path 210A and vertically below the conveying path 210. The processing tray 220 is inclined with respect to the horizontal plane so that the upstream side in the first conveying direction is lower than the downstream side. The processing tray 220 temporarily places a sheet conveyed to the downstream side in the first conveying direction by the pre-processing rollers 211A and 212A. The processing tray 220 can stack a plurality of sheets, and the aligning unit 270A aligns the sheets in the width direction and moves them in the width direction (shifts the sheets) on the processing tray 220. At the upstream end of the processing tray 220 in the first conveying direction, a rear end regulating member 290 is disposed as an abutting unit against which the upstream end edge in the first conveying direction of the sheet placed on the processing tray 220 (the downstream end edge in the second conveying direction opposite to the first conveying direction, the rear end of the sheet) is abutted. A part of the processing tray 220 (for example, the downstream end in the first transport direction) may protrude vertically upward beyond the transport path 210A.

[0027] Further, a staple unit 400 is disposed upstream of the processing tray 220 in the first transport direction as a processing section. The staple unit 400 performs a predetermined process of stapling (binding) the sheet stack that has been aligned in the width direction and has its rear end regulated by the processing tray 220. The staple unit 400 can change the staple position for the sheet stack, and moves according to the staple position. The predetermined process may be other processes such as punching other than stapling. The sheet or sheet stack placed on the processing tray 220 is discharged to the stacking tray 300 by upper discharge rollers 230A and lower discharge rollers 230B, as described later.

[0028] [Scraping paddle] The take-in paddle 240A as a second transport section transports the sheet on the processing tray 220 in a second transport direction opposite to the first transport direction (switchback transport). The take-in 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 swing fulcrum 2403 that swingably supports the paddle arm 2402. That is, the paddle arm 2402 can swing up and down around the swing fulcrum 2403, and the paddle section 2401 is rotatably provided at the tip of the paddle arm 2402.

[0029] The pick-up paddle 240A can swing around a swing fulcrum 2403 between a return position where the paddle portion 2401 contacts the upper surface of the sheet on the processing tray 220 to convey the sheet in the second conveying direction, and an upper retreat position where the paddle portion 2401 retreats above the return position. The swing fulcrum 2403 is disposed upstream in the first conveying direction from a pre-processing nip portion 211a, which is a nip position where the pre-processing rollers 211A and 212A hold the sheet, and vertically above the pre-processing nip portion 211a. The paddle arm 2402 extends downstream in the first conveying direction from the swing fulcrum 2403, and the paddle portion 2401 is provided at its tip. As shown in FIG. 3, a pair of pick-up paddles 240A are disposed on both sides in the width direction of an upper discharge roller 230A, which will be described later.

[0030] [Rear end drop part] A pair of trailing end drop members 250A serving as sheet drop sections are provided on both sides of the pair of take-in paddles 240A. That is, the pair of trailing end drop members 250A are disposed on both sides of the take-in paddle 240A in the width direction, and move vertically in conjunction with the take-in paddle 240A as described below, thereby coming into contact with the upper surface of the upstream side of the sheet in the first conveying direction, and dropping the upstream end (rear end) of the sheet toward the processing tray 220. Note that the trailing end drop members 250A may be driven separately from the take-in paddle 240A.

[0031] The trailing end dropping member 250A has a rotation shaft 2501 as a rotation center downstream in the first transport direction from the pre-processing rollers 211A, 212A as a pair of transport rollers. The trailing end dropping member 250A extends from the rotation shaft 2501 to the upstream side in the first transport direction and is rotatable about the rotation shaft 2501 from an upper position above the pre-processing rollers 211A, 212A to a lower position below the pre-processing rollers 211A, 212A. By rotating from the upper position to the lower position, the trailing end dropping member 250A abuts against the sheet transported by the pre-processing rollers 211A, 212A from above and drops the sheet onto the processing tray 220 below.

[0032] [Return part] The returning member 280 further transports the sheet transported by the take-in paddle 240A toward the trailing end regulating member 290 as described above, and brings the trailing end of the sheet into contact with the trailing end regulating member 290 to regulate the trailing end position of the sheet. Such a returning member 280 is formed of a knurled belt 281, and by rotating and driving the knurled belt 281, the returning member 280 further takes in the sheet transported upstream in the first transport direction by the take-in paddle 240A, and brings the trailing end into contact with the trailing end regulating member 290. The returning member 280 is movable between a contact position where it can contact the sheet and a retracted position retracted upward from the contact position, and moves to the contact position when the sheet is transported toward the trailing end regulating member 290, and moves to the retracted position when the sheet on the processing tray 220 is transported toward the stacking tray 300.

[0033] [Discharge roller] The upper discharge roller (upper discharge rotator) 230A and the lower discharge roller (lower discharge rotator) 230B constitute a pair of discharge rotators, a pair of discharge rollers, and a discharge section, and transport and discharge the sheet transported downstream in the first transport direction by the pre-processing rollers 211A and 212A downstream of the processing tray 220 in the first transport direction. The upper discharge roller 230A can move between a clamping position (contact position) where the sheet is clamped between the lower discharge roller 230B and a retracted position retracted upward from the clamping position, and clamps the sheet between the lower discharge roller 230B at the clamping position. That is, the upper discharge roller 230A functions as a nipping member that nips the sheet between the lower discharge roller 230B at the clamping position. The upper discharge roller 230A and the lower discharge roller 230B are arranged in pairs, spaced apart from each other in the width direction of the sheet. In this embodiment, the pair of sweeping paddles 240A are disposed on the inner side in the width direction.

[0034] The upper discharge roller 230A and the lower discharge roller 230B hold a sheet or a sheet stack at the clamping position, and the lower discharge roller 230B rotates to convey the clamped sheet or sheet stack. The upper discharge roller 230A is a driven roller that rotates following the rotation of the lower discharge roller 230B, but it may be driven. That is, in this embodiment, the upper discharge roller 230A is a driven rotating body, and the lower discharge roller 230B is a driving rotating body. The upper discharge roller 230A functions as a nip member that can hold a sheet between the lower discharge roller 230B at the clamping position, but this nip member may be another rotating body such as a belt instead of a roller, or may be an abutting member that abuts against the sheet without rotating, such as a lever member.

[0035] The lower discharge roller 230B may be a rotating body such as a belt other than a roller. When the lower discharge roller 230B as the lower discharge rotating body is an endless belt, for example, this belt is stretched by a plurality of rollers, and the outer circumferential surface of the belt stretched by one of the rollers abuts against a nip member such as the upper discharge roller 230A to form the discharge nip portion 230a (see FIG. 9(b) described later). In this case, the rotation axis of the lower discharge rotating body is the rotation axis of the roller that stretches the belt at the position where the discharge nip portion 230a is formed.

[0036] The upper discharge roller 230A can rotate around the rotation shaft 2301 between the clamping position and the retreat position. In other words, the upper discharge roller 230A can move up and down between the clamping position and the retreat position. The upper discharge roller 230A is provided at the tip of a discharge arm 2302 serving as a support. The rotation shaft 2301 is provided coaxially with the swing fulcrum 2403 described above, and is disposed upstream in the first conveying direction from the pre-processing nip portion 211a where the pre-processing rollers 211A and 212A clamp the sheet, and vertically above the pre-processing nip portion 211a. The discharge arm 2302 is extended from the rotation shaft 2301 to the downstream side in the first conveying direction, and the upper discharge roller 230A is provided at the tip of the discharge arm 2302. The rotation shaft 2301 does not have to be disposed coaxially with the swing fulcrum 2403, but in this embodiment, the rotation shafts of the upper discharge roller 230A and the pick-up paddle 240A are disposed coaxially.

[0037] The pivot shaft 2301 is disposed upstream in the first conveying direction of a discharge nip portion where the upper discharge roller 230A nips the sheet between the lower discharge roller 230B and the upper discharge roller 230A at the clamping position. In addition, the upper discharge roller 230A is located vertically above the pre-processing nip portion 211a where the pre-processing rollers 211A and 212A nips the sheet at the retracted position, and the pivot shaft 2301 is located vertically above the center of the upper discharge roller 230A at the retracted position.

[0038] Since the positional relationship between the rotation shaft 2301 and the pre-processing nip portion 211a is defined as described above, the upper discharge roller 230A allows the sheet that has passed through the pre-processing nip portion 211a to move toward the stacking tray 300 when in the retracted position. Meanwhile, the upper discharge roller 230A moves downward from the retracted position toward the clamping position by rotating counterclockwise in FIG. 2 about the rotation shaft 2301. Then, the upper discharge roller 230A moves to the clamping position, whereby the sheet can be clamped between the upper discharge roller 230A and the lower discharge roller 230B.

[0039] [Matching part] The alignment section 270A as a shift section will be described with reference to Figs. 2 and 3 as well as Figs. 4(a) to 4(c). The alignment section 270A moves in a shift direction (width direction) intersecting with the first transport direction while being in contact with an edge of the sheet transported downstream in the first transport direction by the pre-processing rollers 211A and 212A, thereby moving the sheet in the shift direction. The alignment section 270A has a pair of alignment plates 271A as a first shift section and a second shift section, which are arranged to face each other in the shift direction.

[0040] The pair of alignment plates 271A are disposed further downstream than the downstream end of the conveying path 210A in the first conveying direction, and align the sheet in the width direction by moving in the width direction and contacting the width direction edge of the sheet. In this embodiment, the pair of alignment plates 271A are disposed on both sides of 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 extend from the upstream side to the downstream side in the first conveying direction with respect to the upper discharge roller 230A and the lower discharge roller 230B. That is, the pair of alignment plates 271A are disposed so as to straddle the upper discharge roller 230A and the lower discharge roller 230B in the first conveying direction. The pair of alignment plates 271A have the same configuration. The pair of alignment plates 271A move in the shift direction by driving the front side (F side) alignment plate moving motor MT16 and the rear side (R side) alignment plate moving motor MT17 (see FIG. 13) as the first and second driving units. In the pair of alignment plates 271A, the alignment plate on the upstream side in the shift direction is defined as a first shift section, and the alignment plate on the downstream side in the shift direction is defined as a second shift section in a first shift discharge process (switchbackless shift discharge process) and a second shift discharge process (switchback shift discharge process) described later. In addition, the motor that drives the first shift section is defined as a first drive section, and the motor that drives the second shift section is defined as a second drive section.

[0041] The alignment plate 271A is formed so that the width in the vertical direction is wider on the downstream side in the first transport direction. That is, the alignment plate 271A has a first plate portion 2701 on the downstream side in the first transport direction, and a second plate portion 2702 formed so as to be continuous with the first plate portion 2701 on the upstream side in the first transport direction. The first plate portion 2701 has a larger area in the vertical direction than the second plate portion 2702 so that the first plate portion 2701 can abut against the sheet even if the leading end side of the transported sheet is curled upward or downward. On the other hand, the second plate portion 2702 is formed so that the height in the vertical direction is lower than that of the first plate portion 2701 so that the second plate portion 2702 does not interfere with the trailing end dropping member 250A even if the trailing end dropping member 250A is located at a lower position. In addition, the upper edge of the second plate portion 2702 is inclined so as to become lower toward the upstream side in the first transport direction.

[0042] The first plate portion 2701 is formed so as to straddle the upper discharge rollers 230A and the lower discharge rollers 230B from the upstream side to the downstream side in the first transport direction. This allows at least the first plate portion 2701 to come into contact with the sheet even when the sheet is discharged by a first shift discharge process described later. The second plate portion 2702 is located on the processing tray 220 and is formed continuously with the first plate portion 2701 in the first transport direction. This allows at least the second plate portion 2702 to come into contact with the sheet placed on the processing tray 220 by a second shift discharge process described later.

[0043] As shown in Fig. 4(a) to Fig. 4(c), the first plate portion 2701 has a curl suppressing portion 2703 and a support portion 2704. The curl suppressing portion 2703 is provided downstream in the first conveying direction from a discharge nip portion 230a (see Fig. 9(b) described later), which is a nip position where a sheet is sandwiched between the upper discharge roller 230A and the lower discharge roller 230B, and vertically above the discharge nip portion 230a, and suppresses the leading edge of a sheet curled upward. In this embodiment, the curl suppressing portion 2703 is a protruding portion protruding from the upper end portion of the first plate portion 2701 toward the inside in the width direction (the side that contacts the sheet, the right side in Fig. 4(b)), and the leading edge of the curled sheet is pressed by the abutment of the width direction edge of the curled sheet. In addition, an uneven portion 2705 is provided below the curl suppression portion 2703. Depending on the state of curl, the widthwise edge of the sheet can be caught in this uneven portion 2705, making it possible to suppress the leading edge of the curled sheet.

[0044] The support portion 2704 is provided downstream in the first conveying direction from the discharge nip portion 230a, which is a nip position where the upper discharge roller 230A and the lower discharge roller 230B hold the sheet, and vertically below the discharge nip portion 230a, and supports the sheet from below. In this embodiment, the support portion 2704 is a protruding portion protruding from the lower end of the first plate portion 2701 toward the inside in the width direction (the side that contacts the sheet, the right side in FIG. 4(b)). Also, as shown in FIGS. 4(a) and 4(c), an inclined portion 2704a that is inclined downward toward the downstream side is formed at the downstream end of the support portion 2704 in the first conveying direction. This makes it possible to smoothly guide the sheet supported by the support portion 2704 to the stacking tray 300. Furthermore, by supporting the sheet downstream of the discharge nip portion 230a in the first transport direction by the support portion 2704, the area where the pair of alignment plates 271A contact the side edges of the sheet can be increased compared to when the sheet is not supported.

[0045] [Loading tray] As described above, the stacking tray 300 as a stacking section stacks sheets discharged by the upper discharge roller 230A and the lower discharge roller 230B. The stacking tray 300 is provided on the downstream side of the processing tray 220 in the first transport direction and is movable vertically downward. The stacking tray 300 is inclined with respect to the horizontal plane so that the upstream side in the first transport direction is lower than the downstream side. The stacking tray 300 is supported so as to be movable in the vertical direction along rails arranged in the vertical direction, for example, and is raised and lowered by driving a stacking tray lifting motor MT20 (FIG. 13) as a lifting means.

[0046] At the upstream end of the stacking tray 300 in the first transport direction, there are provided an upright surface 310a as a stacking side regulating means for regulating the upstream end (rear end) in a predetermined direction of the sheet or sheet bundle stacked on the stacking tray 300, and a rear end presser 310b for pressing the rear end of the sheet abutting against the upright surface 310a. The rear end presser 310b is inclined more toward the downstream side in the first transport direction as it goes upward, so that even if the rear end of the sheet is curled upward, it can be pressed by this rear end presser 310b.

[0047] Further, a rotation shaft 3201 (see FIG. 2 and FIG. 5(a) described later) of the sheet pressing paddle 320 is provided coaxially with a rotation shaft 230B1 (see FIG. 5(a) described later) of the lower discharge roller 230B. The rotation shaft 3201 of the sheet pressing paddle 320 does not have to be coaxial with the rotation shaft 230B1. The rotation shaft 3201 of the sheet pressing paddle 320 is located on the lower surface side of the sheet being discharged by the upper discharge roller 230A and the lower discharge roller 230B. Specifically, the rotation shaft 3201 may be provided between the discharge nip portion 230a (see FIG. 9(b) described later) of the upper discharge roller 230A and the lower discharge roller 230B as a pair of discharge rotors and the upstream end of the stacking tray 300 in the first conveying direction in the vertical direction. In this embodiment, as shown in FIG. 2, the rotation shaft 3201 of the sheet pressing paddle 320 is disposed vertically between the downstream end of the processing tray 220 in the first transport direction and the upper end of the standing surface 310a.

[0048] The stacking tray 300 can be raised and lowered by a stacking tray lifting motor MT20 between a first stacking position and a second stacking position lower than the first stacking position. The second stacking position is a position where the stacking tray 300, which has been lowered when discharging sheets onto the stacking tray 300, switches to an upward movement. When discharging sheets, the stacking tray 300 is raised and lowered, and the sheet pressing paddle 320 rotates to convey (scrape) the sheets on the stacking tray 300 in a second conveying direction opposite to the first conveying direction. Then, the upper surface of the sheet on the stacking tray 300 or a sheet bundle consisting of multiple sheets is pressed down by the sheet pressing paddle 320.

[0049] [Sheet holding paddle peripheral configuration] Here, the configuration of the pressing member and the sheet pressing paddle 320 as a scraping portion of this embodiment will be described with reference to Figures 5(a) and 5(b). Figure 5(a) is a perspective view showing the drive configuration of the lower discharge roller 230B and the sheet pressing paddle 320.

[0050] The lower discharge roller 230B is driven by a discharge roller motor MT14 via a drive transmission mechanism 2300. In the illustrated example, the drive transmission mechanism 2300 is made up of a pulley and a belt, and transmits the rotational drive of the drive shaft of the discharge roller motor MT14 to a rotation shaft 230B1 of the lower discharge roller 230B. On the other hand, the sheet pressing paddle 320 is driven by a take-in motor MT15 as a drive unit via a drive transmission mechanism 3200. In the illustrated example, the drive transmission mechanism 3200 is made up of a pulley and a belt, and transmits the rotational drive of the drive shaft of the take-in motor MT15 to a rotation shaft 3201 of the sheet pressing paddle 320.

[0051] The rotating shaft 230B1 of the lower discharge roller 230B is configured so that the rotating shaft 3201 of the sheet pressure paddle 320 can penetrate through the inside thereof, and the two sheet pressure paddles 320 on both sides of the lower discharge roller 230B in the direction of the rotation axis can be arranged on one rotating shaft 3201. The rotating shaft 230B1 of the lower discharge roller 230B is rotatably supported by the rotating shaft 3201 of the sheet pressure paddle 320 via, for example, a bearing. This allows the lower discharge roller 230B and the sheet pressure paddle 320 to be driven independently by different motors. The drive transmission mechanisms 2300 and 3200 may be configured using other drive transmission members such as multiple gears, in addition to the configuration using pulleys and belts.

[0052] 5(b), the sheet pressing paddle 320 has a fixed portion 3202 fixed to a rotating shaft 3201, and a plate-shaped paddle portion 3203 serving as an elastic contact portion provided on the fixed portion 3202. The paddle portion 3203 extends from the fixed portion 3202 fixed to the rotating shaft 3201 in a direction perpendicular to the rotating shaft 3201. Moreover, the paddle portion 3203 is formed of an elastic material such as rubber (for example, ethylene propylene rubber (EPDM) with a hardness of 30±5 HS(A) ((old JIS K6301, spring type A)). The sheet pressing paddle 320 configured in this manner rotates by rotation of the rotating shaft 3201, and picks up the sheets on the stacking tray 300 as described above. Furthermore, when the paddle portion 3203 comes into contact with a sheet on the stacking tray 300 due to rotation, it elastically deforms, thereby enabling the sheet to be picked up and the rear end of the sheet to be pressed down more reliably. The detailed operation of the sheet pressing paddle 320 will be described later.

[0053] [Drive configuration of each part] Next, the drive configuration of the upper discharge roller 230A, the pick-up paddle 240A, and the trailing end drop member 250A will be described with reference to Figs. 6(a) to 12(c). In this embodiment, the upper discharge roller 230A, the pick-up paddle 240A, and the trailing end drop member 250A are configured to work in conjunction with each other. As shown in Fig. 6(a), the drive configuration 600 includes a processing motor 610 (MT12, Fig. 13) as a drive source, a drive transmission mechanism 611, a rotating shaft 612, and a cam mechanism 613. The processing motor 610 can rotate forward and backward, 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 in which the drive is transmitted by a belt, may be used.

[0054] The rotating shaft 612 is disposed in the width direction above the upper discharge rollers 230A, the pick-up paddles 240A, and the trailing-end dropping member 250A. The cam mechanism 613 is operated by the rotation of the rotating shaft 612. The cam mechanism 613 has a first cam member 620 and a second cam member 630 which rotate together with the rotating shaft 612. The first cam member 620 is disposed between the pair of upper discharge rollers 230A, and operates the upper discharge rollers 230A. The second cam members 630 are provided adjacent to each of the pair of pick-up paddles 240A, and operate the pick-up paddles 240A and the trailing-end dropping member 250A.

[0055] As shown in Fig. 7(a), the first cam member 620 has a groove 621 formed on the inside thereof into which the protrusion 2303 provided on the discharge arm 2302 of the upper discharge roller 230A can enter. The groove 621 has an outer peripheral surface, i.e., an inner peripheral surface of the first cam member 620, as an inner cam surface 622. The inner cam surface 622 is a cam surface whose distance from the rotation center of the rotation shaft 612 varies depending on the phase in the rotation direction. The first cam member 620 also has an outer peripheral surface formed as an 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 varies depending on the phase in the rotation direction.

[0056] In addition to the above-mentioned protrusion 2303, the discharge arm 2302 of the upper discharge roller 230A has an abutment portion 2304 that can abut against an outer cam surface 623 of the first cam member 620. The first cam member 620 rotates together with the rotating shaft 612 to change the abutment position (phase) between the inner cam surface 622 and the protrusion 2303 or separate them, and to change the abutment position (phase) between the outer cam surface 623 and the abutment portion 2304 or separate them, thereby rotating the upper discharge roller 230A around the rotating shaft 2301 between the clamping position and the retracted position, as described below.

[0057] As shown in FIG. 7B, the second cam member 630 has a groove 631 formed on the inside thereof into which the first protrusion 2404 provided on the paddle arm 2402 of the pick-up paddle 240A can enter. The groove 631 has an outer peripheral surface, i.e., an inner peripheral surface of the second cam member 630, as an inner cam surface 632. The inner cam surface 632 is a cam surface whose distance from the center of rotation of the rotating shaft 612 varies depending on the phase in the rotation direction. The second cam member 630 rotates together with the rotating shaft 612 to change the contact position (phase) between the inner cam surface 632 and the first protrusion 2404, thereby rotating the pick-up paddle 240A around the swing fulcrum 2403 between a return position and an upper retracted position, as described below.

[0058] 7(c) and 8, a support portion 2406 that swings about a swing fulcrum 2403 together with the paddle arm 2402 of the pick-up paddle 240A and supports an end of the rotation shaft 2401a of the paddle portion 2401 is provided with a second protrusion 2405 that can enter an engagement recess 2502 formed in the trailing end dropping member 250A. When the pick-up paddle 240A rotates, the engagement recess 2502 abuts against or separates from the second protrusion 2405, thereby rotating the trailing end dropping member 250A between an upper position and a lower position about the rotation shaft 2501 in conjunction with the rotation of the pick-up paddle 240A. The driving of the upper discharge roller 230A, the pick-up paddle 240A, and the trailing end dropping member 250A will be specifically described below.

[0059] [Home position] 6(a) to 7(c) show the home positions (HP) of the upper discharge roller 230A, the pick-up paddle 240A, and the trailing-end dropping member 250A. At the home positions, as shown in FIGS. 6(a) and 6(b), the upper discharge roller 230A is in the retracted position, the pick-up paddle 240A is in the upper retracted position, and the trailing-end dropping member 250A is in the upper position.

[0060] In this state, as shown in FIG. 7(a), the protrusion 2303 of the upper discharge roller 230A abuts at a position close to the center of the rotation shaft 612 of the inner cam surface 622 of the first cam member 620, so that the upper discharge roller 230A is supported by the first cam member 620.

[0061] Furthermore, as shown in FIG. 7(b), the first protrusion 2404 of the sweeping paddle 240A abuts at a position close to the center of the rotation shaft 612 of the inner cam surface 632 of the second cam member 630, thereby supporting the sweeping paddle 240A on the second cam member 630.

[0062] Furthermore, as shown in FIG. 7(c), the engagement recess 2502 of the trailing end dropping member 250A abuts against the second protrusion 2405 of the sweeping paddle 240A, so that the trailing end dropping member 250A is supported by the sweeping paddle 240A via the second protrusion 2405.

[0063] [Upper ejection roller lowering] Next, the operation of moving the upper discharge roller 230A from the home position (retracted position) to the clamping position will be described with reference to Fig. 9(a) to Fig. 10(c). When the processing motor 610 is driven to rotate the rotating shaft 612 in a first direction (counterclockwise in Fig. 10(a) and (b)) in order to lower the upper discharge roller 230A from the home position, the first cam member 620 also rotates in the same direction, and the protrusion 2303 moves along the inner cam surface 622. The inner cam surface 622 is formed so that the distance from the center of the rotating shaft 612 increases when the inner cam surface 622 rotates counterclockwise from the home position. Therefore, this operation causes the upper discharge roller 230A to descend.

[0064] Next, when the upper discharge roller 230A moves to the clamping position and comes into contact with the lower discharge roller 230B, as shown in Fig. 10(a), the inner cam surface 622 of the first cam member 620 separates from the protrusion 2303, 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 manner, the upper discharge roller 230A is pressed toward the lower discharge roller 230B, and a predetermined nip pressure is applied between these rollers.

[0065] At this time, the second cam member 630 also rotates together with the rotating shaft 612, but as shown in FIG. 10(b), the distance from the center of the rotating shaft 612 to the position where the inner cam surface 632 abuts against the first protrusion 2404 is approximately the same as the distance at the home position. Therefore, even if the second cam member 630 rotates, the pick-up paddle 240A is maintained at the home position. Since the pick-up paddle 240A is maintained at the home position, the trailing end dropping member 250A is also maintained at the home position, as shown in FIG. 10(c). That is, in this state, as shown in FIG. 9(b), the upper discharge roller 230A moves to the clamping position, but the pick-up paddle 240A and the trailing end dropping member 250A are maintained at the home position.

[0066] When the upper discharge roller 230A is raised, the processing motor 610 is driven to rotate the rotating shaft 612 in a second direction opposite to the first direction (counterclockwise in Figs. 10(a) and (b)). Then, the first cam member 620 rotates together with the rotating shaft 612 in the same direction, and the protrusion 2303 moves along the inner cam surface 622, and the upper discharge roller 230A is raised. Then, it returns to the home position shown in Fig. 7(a).

[0067] Here, when the scavenging paddle 240A and the trailing end dropping member 250A return from the state of Figures 10(b) and (c) to the state of Figures 7(b) and (c), the first protrusion 2404 moves along the inner cam surface 632 of the second cam member 630, but the inner cam surface 632 is formed so that the distance from the center of the rotation shaft 612 to the position where the inner cam surface 632 abuts against the first protrusion 2404 does not change. Therefore, the scavenging paddle 240A remains in the home position. Since the scavenging paddle 240A is maintained in the home position, the trailing end dropping member 250A also remains in the home position.

[0068] [Lowering of the raking paddle and rear end drop member] Next, the operation of moving the pick-up paddle 240A and the trailing end dropping member 250A from the home position (upper retracted position, upper position) to the return position and the lower position will be described with reference to Figs. 11(a) to 12(c). In order to lower the pick-up paddle 240A and the trailing end dropping member 250A from the home position, when the processing motor 610 is driven to rotate the rotating shaft 612 in a second direction (clockwise in Figs. 12(a) and 12(b)) opposite to the first direction, the first cam member 620 also rotates in the same direction, and the protrusion 2303 moves along the inner cam surface 622. The inner cam surface 622 is formed so that the distance from the center of the rotating shaft 612 does not change substantially even when the inner cam surface 622 rotates clockwise from the home position. Therefore, as shown in Fig. 12(a), the upper discharge roller 230A is maintained at the home position.

[0069] Meanwhile, the second cam member 630 also rotates in the same direction together with the rotating shaft 612, and the first protrusion 2404 moves along the inner cam surface 632. The inner cam surface 632 is formed so that when it rotates clockwise from the home position, it becomes more distant from the center of the rotating shaft 612. Therefore, this action causes the sweeping paddle 240A to descend and move to the return position.

[0070] At this time, the trailing end dropping member 250A also descends together with the pick-up paddle 240A. In this embodiment, the trailing end dropping member 250A has a positioning portion 2503 that is positioned at the lower position by engaging with the upper guide 2101 of the conveying path 210A when it rotates from the upper position to 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 (upstream end in the first conveying direction) of the trailing end dropping member 250A. The protruding portion 2504 also has a role of regulating the leading end of the sheet conveyed toward the pre-processing nip portion 211a on the upstream side in the first conveying direction of the pre-processing nip portion 211a when the trailing end dropping member 250A is in the lower position.

[0071] The positioning portion 2503 is an engagement portion provided on the upper end of the protrusion 2504 so as to be able to engage with the upper guide 2101, and by abutting against the upper surface of the upper guide 2101, it prevents the trailing end dropping member 250A from descending any further. The engagement recess 2502 is formed so as to be separated from the second protrusion 2405 in this state. Therefore, the trailing end dropping member 250A is disengaged from the sweeping paddle 240A, and is positioned at a lower position by the positioning portion 2503.

[0072] As a result, even if the pick-up paddle 240A reaches the return position, the trailing end dropping member 250A is not lowered any further and is positioned at the lower position due to the engagement between the positioning portion 2503 and the upper guide 2101. In this state, as shown in Fig. 11(b), the pick-up paddle 240A and the trailing end dropping member 250A move to the return position and the lower position, and the upper discharge roller 230A is located at the home position.

[0073] The above-mentioned protrusion 2504 and positioning portion 2053 shown in Fig. 12(c) are omitted in Fig. 1 to Fig. 11(b). Such protrusion 2504 and positioning portion 2053 may be omitted, in which case a separate positioning mechanism may be provided to position the trailing-end dropping member 250A at the lower position. For example, positioning may be performed by engaging the engagement recess 2502 with the second protrusion 2405 at the lower position.

[0074] When the sweeping paddle 240A and the trailing end dropping member 250A are raised, the motor 610 is driven to rotate the rotating shaft 612 in a first direction (counterclockwise in Figs. 12(a) and (b)). Then, the second cam member 630 rotates together with the rotating shaft 612 in the same direction, the first protrusion 2404 moves along the inner cam surface 632, and the sweeping paddle 240A rises. At this time, the second protrusion 2405 re-engages with the engagement recess 2052, and this engagement also raises the trailing end dropping member 250A. Then, the sweeping paddle 240A and the trailing end dropping member 250A return to their home positions shown in Figs. 6(a) to 7(c).

[0075] 7(a) from the state of Fig. 12(a), the protrusion 2303 moves along the inner cam surface 622 of the first cam member 620, but the inner cam surface 622 is formed so that the distance from the center of the rotation shaft 612 to the position where the inner cam surface 622 abuts against the protrusion 2303 does not change at this time. Therefore, the upper discharge roller 230A remains maintained at the home position.

[0076] In this embodiment, when the rotating shaft 612 is rotated from the home position in the counterclockwise direction in Figures 7(a) to 7(c), the upper discharge roller 230A is lowered, and the pick-up paddle 240A and the trailing end drop-off member 250A are maintained in the home position. On the other hand, when the rotating shaft 612 is rotated from the home position in the clockwise direction in Figures 7(a) to 7(c), the upper discharge roller 230A is maintained in the home position, and the pick-up paddle 240A and the trailing end drop-off member 250A are lowered.

[0077] 10(a) to 10(c), the upper discharge roller 230A is raised, and the pick-up paddle 240A and the trailing end drop-off member 250A are maintained in their home positions. On the other hand, when the rotation shaft 612 is rotated in the counterclockwise direction in FIG. 12(a) to 12(c), the upper discharge roller 230A is maintained in its home position, and the pick-up paddle 240A and the trailing end drop-off member 250A are raised, with the pick-up paddle 240A and the trailing end drop-off member 250A in their return and lower positions.

[0078] Fig. 13 shows the relationship between each motor and each component. The columns in Fig. 13 show, from the left, the number, motor name, driving parts, operation, direction of operation during forward rotation, and direction of operation during reverse rotation. In Fig. 13, the processing motor MT12 is the processing motor 610 described above. As is clear from Fig. 13, 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 pick-up paddle 240A, and the returning member 280.

[0079] Further, the processing motor MT12 raises and lowers the pick-up paddle 240A, the trailing end drop member 250A, and the upper discharge roller (nip member) 230A. In this embodiment, in addition to the above, there is provided a return lift motor MT13 for raising and lowering the returning member 280, a discharge roller motor MT14 for driving the lower discharge roller 230B, a pickup motor (sheet holding motor) MT15 for driving the discharge pickup paddle (sheet holding (bundle holding) paddle) 320, an F-side alignment plate moving motor MT16 for moving (laterally) the front alignment plate 271A in the width direction, an R-side alignment plate moving motor MT17 for moving (laterally) the rear alignment plate 271A in the width direction, 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 lift motor MT20 for raising and lowering the loading tray 300.

[0080] [Control configuration of sheet processing device] The control configuration of the sheet processing apparatus 200 will be described with reference to Figs. 14 and 15. Fig. 14 is a block diagram showing each motor and each sensor of the sheet processing apparatus 200. Signals from each of these sensors are input to a control unit 203 as a control means, and each motor is controlled by the control unit 203. The control unit 203 is communicably connected to a control unit of the image forming apparatus 100, and controls the entire sheet processing apparatus 200.

[0081] Such a control unit 203 has a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). The CPU controls each unit while reading a program corresponding to a control procedure stored in the ROM. Working data and input data are stored in the RAM, and the CPU performs control by referring to the data stored in the RAM based on the above-mentioned programs, etc.

[0082] Each motor shown in FIG. 14 is as described above. Meanwhile, each sensor will be described with reference to FIG. 2. First, the entrance sensor SN11 is provided on the conveying path 210A and detects the leading edge of the sheet conveyed to the conveying path 210A. The processing upper HP sensor SN12 detects the home positions of the take-in paddle 240A, the trailing end dropping member 250A, and the upper discharge roller (nip member) 230A. The return lift HP sensor SN13 detects the home position of the return member 280 (a position retracted 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 paddle HP sensor (sheet pressing HP sensor) SN15 detects the home position of the sheet pressing paddle 320.

[0083] The F-side alignment plate HP sensor SN16 and the R-side alignment plate HP sensor SN17 respectively detect that the front alignment plate 271A and the rear alignment plate 271A are in positions (home positions) spaced apart in the width direction from the sheets 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 top sheet placed on the stacking tray 300. The stacking tray encoder sensor SN20 detects the position of the stacking tray 300 in the lifting / lowering direction. The stacking tray lower limit position detection sensor SN21 detects the lower limit position of the stacking tray 300. The control unit 203 performs various controls, as described below, based on the signals of these sensors.

[0084] Next, the flow of control in each mode of this embodiment will be described with reference to Fig. 15. In this embodiment, there are a straight discharge mode in which a sheet sent to the sheet processing apparatus 200 is discharged directly to the stacking tray 300 without undergoing a predetermined process, a shift mode in which a sheet sent to the sheet processing apparatus 200 is shifted in the width direction (shifted) and discharged to the stacking tray 300 in order to separate the sheets discharged to the stacking tray 300, and a staple mode in which a sheet sent to the sheet processing apparatus 200 is stapled as a predetermined process and discharged to the stacking tray 300. Each of these modes is selected by a user through an operation panel of the image forming apparatus 100 or a PC connected via a network or the like.

[0085] In this embodiment, the mode can be set manually by the user or automatically based on the paper type (sheet length), and in the shift mode, whether to select the first shift discharge process or the second shift discharge process described below can be set appropriately depending on the final product desired by the user.

[0086] In the staple mode as the binding and discharging process, the sheet conveyed downstream in the first conveying direction by the pre-processing rollers 211A and 212A is conveyed in the second conveying direction by the pick-up paddle 240A on the processing tray 220, and the downstream edge (rear end) of the sheet in the second conveying direction is abutted against the rear end regulating member 290, that is, the rear end of the sheet is regulated. Then, the alignment section 270A (a pair of alignment plates 271A) is driven by the F-side alignment plate moving motor MT16 and the R-side alignment plate moving motor MT17, so that the sheet abutted against the rear end regulating member 290 by the alignment section 270A is moved in the sheet width direction (the same direction as the shift direction) and positioned at the binding position. That is, the alignment process is performed. In this embodiment, the pair of alignment plates 271A is used for center alignment, and the sheets are aligned by hitting them from both sides in the sheet width direction. By repeating such an operation of regulating the rear end of the sheet and the alignment process, a sheet stack is formed on the processing tray 220. Thereafter, the sheet stack positioned at the binding position is stapled, and the stapled sheet stack is discharged by the upper discharge rollers 230A and the lower discharge rollers 230B onto the stacking tray 300. In the following shift mode, the pair of alignment plates 271A, the F-side alignment plate moving motor MT16, and the R-side alignment plate moving motor MT17 used in the alignment process when forming the sheet stack in this staple mode are used to perform a shift operation of sheets that are not to be stapled.

[0087] In the shift mode, there are a case where the shift operation is performed on a sheet (first sheet, small size sheet) whose length in the sheet conveying direction (first conveying direction) is a first length, and a case where the shift operation is performed on a sheet (second sheet, large size sheet) whose length in the first conveying direction is a second length longer than the first length. The small size sheet is, for example, a sheet whose length in the first conveying direction is equal to or shorter than a predetermined length, and the large size sheet is, for example, a sheet whose length in the first conveying direction is longer than a predetermined length. The predetermined length is, for example, a so-called A4 vertical size in which an A4 size paper is sent in a vertical direction (the direction in which the longitudinal direction is the conveying direction). In the shift mode, a productivity priority mode that prioritizes productivity and an alignment priority mode that prioritizes sheet alignment can be selected and executed. In any shift mode, the sheet can be shifted in both directions, from the rear side to the front side and from the front side to the rear side (the shift direction is both directions).

[0088] The switchbackless shift discharge process and the productivity priority mode as the first shift discharge process are modes in which the sheet transported downstream in the first conveying direction by the pre-processing rollers 211A, 212A is not transported in the second conveying direction by the pick-up paddle 240A, but is instead moved (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, and is discharged onto the stacking tray 300 by the upper discharge rollers 230A and the lower discharge rollers 230B.

[0089] In the alignment priority mode as the switchback shift discharge process and the second shift discharge process, a sheet conveyed downstream in the first conveying direction by the pre-processing rollers 211A, 212A is conveyed in the second conveying direction by the take-in paddle 240A on the processing tray 220, and the downstream edge of the sheet in the second conveying direction is abutted (regulated) against the trailing end regulating member 290, and then, without stapling by the staple unit 400, a switchback shift operation is performed in which the sheet is moved (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, and the sheet is discharged onto the stacking tray 300 by the upper discharge rollers 230A and the lower discharge rollers 230B. A detailed description of this point will be given later.

[0090] When control is started, the control unit 203 determines whether the discharge mode is the straight discharge mode, the shift mode, or the staple mode (S1). If the straight discharge mode is selected, the sheets sent to the sheet processing device 200 are discharged one by one onto the stacking tray 300 without undergoing any predetermined processing (S2).

[0091] If the shift mode is selected in S1, it is determined whether the sheet size is a large size sheet or a small size sheet (S3). If it is a small size sheet, it is determined whether productivity is prioritized (S4). If productivity is prioritized, the sheet discharged from the conveying path 210A is not conveyed in the second conveying direction by the processing tray 220, but is shifted by the alignment unit 270A and discharged to the stacking tray 300 (S5). If productivity is not prioritized in S4, the sheet discharged from the conveying path 210A is put into the processing tray 220, and is shifted by the alignment unit 270A on the processing tray 220 and discharged to the stacking tray 300 (S6). If the sheet is a large size sheet in S3, the process also proceeds to S6.

[0092] In S1, when the staple mode is selected, the sheet discharged from the conveying path 210A is conveyed in the second conveying direction on the processing tray 220 by the pick-up paddle 240A, and the downstream edge of the sheet in the second conveying direction is abutted against the trailing end regulating member 290. That is, the trailing end of the sheet is regulated. Then, after regulating the trailing 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 at the binding position by the alignment section 270A (a pair of alignment plates 271A). Such operations of regulating the trailing end of the sheet and aligning are 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 stacking tray 300 (S9).

[0093] The operation of the sheet processing apparatus 200 in the first shift discharge process and the second shift discharge process in the shift mode will be described with reference to FIGS. 16(a) to 35(b).

[0094] [First shift discharge process (productivity priority mode)] First, the first shift discharge process (productivity priority mode) of the shift mode will be described with reference to Fig. 16(a) to Fig. 25(b). As shown in Fig. 16(a) and (b), when the sheet S has not yet been conveyed to the conveying path 210A, the upper discharge roller 230A, the pick-up paddle 240A, and the trailing end drop member 250A are each located at their home positions. Also, the pair of alignment plates 271A are located at their home positions, which are the positions furthest apart from each other.

[0095] 17(a) and 17(b), when the sheet S is conveyed to the entrance of the conveying path 210A, the pair of alignment plates 271A move from their home positions toward each other and wait at the receiving position for receiving the sheet. Also, even in this state, the upper discharge roller 230A, the pick-up paddle 240A, and the trailing end drop member 250A are each located at their home positions.

[0096] 18(a) and (b), when the downstream end (leading end) of the sheet S in the first conveying direction passes through the pre-processing nip portion 211a of the pre-processing rollers 211A and 212A and the leading end of the sheet S passes through the lower discharge roller 230B, the upper discharge roller 230A starts to descend. For example, when the leading end of the sheet S reaches a position 10 mm downstream from the nip position where the upper discharge roller 230A and the lower discharge roller 230B nip the sheet, 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 upper discharge roller 230A is positioned closer to the lower discharge roller 230B than the retracted position, and the upper discharge roller 230A and the lower discharge roller 230B are positioned at a separated position where they are separated from each other. At this time, the pick-up paddle 240A and the trailing end drop member 250A remain in their home positions.

[0097] 19(a) and (b), when the upstream end (rear end) of the sheet S in the first transport direction passes through the pre-processing nip portion 211a of the pre-processing rollers 211A and 212A, the upper discharge roller 230A is lowered to the nip position, and the sheet is nipped between the upper discharge roller 230A and the lower discharge roller 230B. In addition, 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 portion 211a, the upper discharge roller 230A is positioned at the nip position. As a result, the sheet S is nipped between the upper discharge roller 230A and the lower discharge roller 230B, and transport is stopped.

[0098] 20(a) and (b), the upper discharge rollers 230A are raised to the separated position, and the pair of alignment plates 271A are moved to widthwise positions that match the size of the sheet S. This results in the sheet S being sandwiched from both sides in the widthwise direction (both sides in the shift direction). Note that because the sheet S is sandwiched between the pair of alignment plates 271A, the sheet S is prevented from shifting in the first transport direction or the second transport direction even if the upper discharge rollers 230A are raised to the separated position.

[0099] Then, as shown in Figs. 21(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 Figs. 22(a) and (b), the upper discharge roller 230A is lowered to the sandwiching position, and the sheet S is again 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 Figs. 23(a) and (b). In this example, since the shift direction is from the rear side to the front side, the rear alignment plate of the pair of alignment plates 271A is defined as the first shift part, and the front alignment plate is defined as the second shift part. In addition, the rear alignment plate moving motor MT17 is defined as the first drive part, and the front alignment plate moving motor MT16 is defined as the second drive part. Conversely, when the shift direction is from the front side to the rear side, the front alignment plate of the pair of alignment plates 271A is the first shift part, and the rear alignment plate is the second shift part. Also, the front alignment plate moving motor MT16 is the first drive part, and the rear alignment plate moving motor MT17 is the second drive part.

[0100] 24(a) and (b), the lower discharge roller 230B is rotated to discharge the sheet S nipped between the upper discharge roller 230A and the lower discharge roller 230B onto the stacking tray 300. After the sheet S is discharged onto the stacking tray 300, the sheet S is picked up by the sheet pressing paddle 320 and the rear end of the sheet S is pressed down, as shown in FIGS. 25(a) and (b). At this time, the pair of alignment plates 271A move to the receiving position to receive the next sheet.

[0101] In such a productivity priority mode, since there is no operation of transporting the sheet S in the second transport direction on the processing tray 220 (switchback transport), the shift operation of the sheet S can be performed faster than when it is performed on the processing tray 220. Note that the productivity priority mode is preferably applicable to small size sheets, but may also be executed for large size sheets. In other words, it may be executed for all sheets that are shifted and discharged without being stapled.

[0102] [Second shift discharge process (alignment priority mode)] Next, the second shift discharge process (alignment priority mode) of the shift mode will be described with reference to Fig. 26(a) to Fig. 35(b). The alignment priority mode may be performed for small size sheets, but here, the case where it is performed for large size sheets will be described. The state where the sheet S has not yet been conveyed to the conveying path 210A, and the state where the sheet S has been conveyed to the entrance of the conveying path 210A are the same as Fig. 16(a) to Fig. 17(b) shown in the first shift discharge process.

[0103] 26(a) and 26(b), in the second shift discharge process, even if the downstream end (leading end) of the sheet S in the first transport direction passes through the pre-processing nip portion 211a of the pre-processing rollers 211A and 212A and the leading end of the sheet S passes through the lower discharge roller 230B, the upper discharge roller 230A does not descend. That is, in this state, the upper discharge roller 230A, the pick-up paddle 240A, and the trailing end drop member 250A remain positioned at their home positions.

[0104] 27(a) and (b), when the upstream end (rear end) of the sheet S in the first transport direction passes through the pre-processing nip portion 211a of the pre-processing rollers 211A and 212A, the pick-up paddle 240A starts to descend. Then, as shown in FIGS. 28(a) and (b), the pick-up paddle 240A is placed in the return position and the rear end dropping member 250A is placed in the lowered position, so that the sheet S is dropped onto the processing tray 220 and the pick-up paddle 240A transports the sheet S in the second transport direction.

[0105] 29(a) and (b), the return member 280 (knurled belt 281) is also lowered, and the sheet S is conveyed in the second conveying direction by the pick-up paddle 240A and the return member 280, and the rear end of the sheet S is brought into contact with the rear end regulating member 290. Thereafter, as shown in FIGS. 30(a) and (b), the pick-up paddle 240A, the rear end dropping member 250A, and the return member 280 are raised. In this state, as shown in FIGS. 31(a) and (b), of the pair of alignment plates 271A, only the alignment plate 271A (first shift portion) on the upstream side in the shift direction (upper side in FIG. 31(a)) 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 sandwiching the sheet between the pair of alignment plates 271A. The alignment plate 271A on the downstream side (lower side in FIG. 31(a)) waits at the receiving position when the shift operation starts, and moves from this receiving position in the shift direction according to the shift amount of the sheet S. Note that, during the shift operation by the alignment plate 271A, the knurled belt 281 may be brought into contact with the upper surface of the sheet in a rotating state. This causes the shift operation to be performed with the rear end of the sheet abutting against the rear end regulating member 290, so that the behavior of the sheet becomes stable.

[0106] The reason why the downstream alignment plate 271A is not moved from the receiving position toward the sheet S side in this manner is that, in the second shift discharge process, the shift operation can be performed with multiple sheets placed on the processing tray 220. That is, when performing the shift operation for the second and subsequent sheets, if the downstream alignment plate 271A is moved from the receiving position toward the sheet S side, the first sheet will also be pushed and moved by the downstream alignment plate 271A, which may disrupt the alignment of the first sheet.

[0107] When the shift operation of the sheet S is completed, as shown in Fig. 32(a) and (b), the upper discharge roller 230A is lowered to the clamping position, 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 is retracted from the sheet S, as shown in Fig. 33(a) and (b). In this example, the case where the second shift discharge process is performed on one sheet S will be described, but when the second shift discharge process is performed 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 manner as the sheet S described above.

[0108] When discharging the sheet that has undergone the shift operation, with the upper discharge roller 230A positioned at the nip position, i.e., in the state shown in Figs. 33(a) and (b), the lower discharge roller 230B is rotated as shown in Figs. 34(a) and (b), and the sheet S nipped between the upper discharge roller 230A and the lower discharge roller 230B is discharged onto the stacking tray 300. After the sheet S is discharged onto the stacking tray 300, the sheet pressing paddle 320 picks up the sheet S and further presses the rear end of the sheet S, as shown in Figs. 35(a) and (b). At this time, the pair of alignment plates 271A move to the receiving position to receive the next sheet.

[0109] In this way, in the alignment priority mode, the sheets S are aligned and shifted on the processing tray 220, so that the alignment of the sheets S can be improved compared to the productivity priority mode. However, in the alignment priority mode, the sheets are temporarily placed on the processing tray 220, so that the processing takes longer than in the productivity priority mode. However, in the case of large-sized sheets, the processing in the image forming apparatus 100 also takes time. Therefore, when the alignment priority mode is executed for a large-sized sheet, the shift operation can be performed with a productivity suitable for the productivity of the image forming apparatus 100, and further, the alignment of the sheets can be improved. Note that the productivity priority mode as described above may be executed even for a large-sized sheet.

[0110] In this embodiment, when the staple mode, the first shift discharge process, and the second shift discharge process are performed, the front alignment plate moving motor MT16 and the rear alignment plate moving motor MT17, which are common drive sources, are used to perform each process, and the common alignment plate 271A is used. This allows for lower costs compared to a configuration that requires separate alignment plates and drive sources for each process.

[0111] In the above example, the shift operation is performed in the first shift discharge process and the second shift discharge process with the upper discharge roller 230A separated from the lower discharge roller 230B. However, the shift operation may be performed with the nip pressure between the upper discharge roller 230A and the lower discharge roller 230B lowered. That is, in the above example, the drive configuration 600 for moving the upper discharge roller 230A functions as a discharge rotor moving member for moving the upper discharge roller 230A to the clamping position, the separated position, and further to the retreat position. However, the drive configuration 600 may function as a discharge rotor nip pressure switching mechanism for switching the nip pressure for clamping the sheet between the upper discharge roller 230A and the lower discharge roller 230B between the first nip pressure and the second nip pressure that is weaker than the first nip pressure. The shift operation may be performed with the nip pressure set to the second nip pressure. The first nip pressure is a nip pressure when the sheet is discharged between the upper discharge roller 230A and the lower discharge roller 230B.

[0112] In the above example, in the first shift discharge process, the shift operation is performed after the sheet passes through the pre-processing nip portion 211a of the pre-processing rollers 211A and 212A, but the shift operation may be performed while the sheet is in the pre-processing nip portion 211a. Either one of the pre-processing rollers 211A and 212A may be movable between a clamping position where the sheet is clamped and a spaced position where the rollers are separated from each other, and the pre-processing rollers 211A and 212A may be moved to the spaced 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 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 to the clamping position and the spaced position may be the same as that of the second embodiment. Also, a small size sheet may be shifted by the pair of alignment plates 271A after the trailing edge of the sheet passes through the pre-processing nip portion 211a, and a large size sheet may be shifted by the pair of alignment plates 271A after the leading edge of the sheet passes through the discharge nip portion 230a and before the trailing edge of the sheet passes through the pre-processing nip portion 211a. This allows the portion of the large size sheet where the pair of alignment plates 271A come into contact to be closer to the center of gravity of the sheet, and the force with which the sheet rotates during the shift operation can be reduced.

[0113] In the above example, when the first shift discharge process is performed, the pair of alignment plates 271A are moved in the shift direction to shift the sheet S while the sheet S is between the upper discharge roller 230A and the lower discharge roller 230B and the upper discharge roller 230A is positioned at the separation position (or in the second nip pressure state). Similarly, when the second shift discharge process is performed, the pair of alignment plates 271A are moved in the shift direction to shift the sheet S while the sheet S is between the upper discharge roller 230A and the lower discharge roller 230B and the upper discharge roller 230A is positioned at the separation position (or in the second nip pressure state). Furthermore, when performing staple mode, when aligning 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 and the upper discharge roller 230A is positioned at the separated position (or in the second nip pressure state), to align the sheet in the sheet width direction.

[0114] That is, when the sheet S is shifted using the pair of alignment plates 271A in the first shift discharge process, it is necessary to release the nip between the members nipping the sheet S (or change the nip pressure to the second nip pressure), but the nip release mechanism (the 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 shared compared to the second embodiment described later, and the staple mode, the first shift discharge process, and the second shift discharge process can be performed at a lower cost.

[0115] [Formation of sheet stacks by shift discharge processing] Here, in this embodiment, a process of shifting sheets one by one in the shift direction and discharging them onto the stacking tray 300 without binding them to form a sheet bundle consisting of a plurality of unstitched sheets will be described. For example, a plurality of unstitched sheet bundles may be shifted relative to each other in the shift direction and discharged onto the stacking tray 300. As a process of shifting and discharging sheets without stapling them in this way, in this embodiment, the above-mentioned switchback shift discharge process (alignment priority mode) and switchbackless shift discharge process (productivity priority mode) can be executed.

[0116] In the switchbackless shift discharge process, sheets are shifted one by one and discharged onto the stacking tray 300. In this case, if the sheets shifted onto the stacking tray 300 are simply stacked to form a sheet bundle, the alignment of the sheets on the stacking tray 300 may be deteriorated. In addition, even if the sheet bundle is formed on the stacking tray 300 and then the sheet pressing paddle 320 is used to pick up the sheets, only the top sheet of the sheet bundle is picked up, and conversely, the alignment of the sheets may be deteriorated. Therefore, in this embodiment, as described above with reference to FIGS. 25(a) and 25(b), after the sheets are discharged onto the stacking tray 300, the sheets are picked up by the sheet pressing paddle 320.

[0117] That is, when forming a sheet stack shifted onto the stacking tray 300 (on the stacking section) without performing a binding process, the shift discharge process and the scraping process are repeatedly performed on a plurality of sheets to form a sheet stack consisting of a plurality of sheets on the stacking tray 300. The shift discharge process is a process in which the sheet is shifted by the alignment section 270A, and the sheet shifted by the alignment section 270A is discharged onto the stacking tray 300 by the upper discharge rollers 230A and the lower discharge rollers 230B, and is the above-mentioned switchback-less shift discharge process. The scraping process is a process in which the sheet discharged onto the stacking tray 300 is conveyed in the second conveying direction by the sheet pressing paddle 320.

[0118] Furthermore, when the shift discharge process and the take-in process are repeated, the take-in paddle 320 stops at a position on the stacking tray 300 where it presses the upper surface of the sheet that it has taken in until the next sheet is discharged (until the trailing edge of the sheet passes the nip point of the discharge rollers 230). Then, when the next sheet is discharged onto the stacking tray 300, the take-in paddle 320 rotates to take in the sheet and further presses the trailing edge of the sheet. This makes it possible to prevent the sheet that has already been taken in on the stacking tray 300 from being shifted by the next sheet.

[0119] This improves the alignment of the sheet stack when forming an unstitched sheet stack moved in the shift direction on the stacking tray 300. That is, the sheet is shifted and discharged onto the stacking tray 300, and the sheet is further picked up by the sheet pressing paddle 320, so that the sheet discharged onto the stacking tray 300 can be abutted against the standing surface 310a provided at the upstream end of the stacking tray 300 in the first conveying direction. This operation is then repeated for each sheet, so that the alignment of the sheet stack discharged onto the stacking tray 300 can be improved.

[0120] This operation can also be performed in the switchback shift discharge process. That is, when the switchback shift discharge process is performed, a sheet bundle is usually formed on the processing tray 220 and then discharged onto the stacking tray 300. However, the sheets may be shifted one by one on the processing tray 220 and discharged onto the stacking tray 300. Even in this case, as described above with reference to Figures 35(a) and (b), the alignment of the sheet bundle discharged onto the stacking tray 300 can be improved by performing a scraping process on each sheet discharged onto the stacking tray 300.

[0121] [Sheet pressure paddle operation] Next, the operation of the sheet pressing paddle 320 as a pressing member will be described with reference to FIGS. 36 to 47. As described above, the sheet pressing paddle 320 presses down the upper surface of the sheet discharged onto the stacking tray 300. The sheet pressing paddle 320 rotates around the rotation shaft 3201, so that the paddle portion 3203 comes into contact with the upper surface of the sheet. At this time, if the paddle portion 3203 comes into contact with the upper surface of the sheet forcefully, a collision sound may be generated. For this reason, in this embodiment, the take-in motor MT15 rotates the sheet pressing paddle 320 from a state in which the sheet is being stacked on the stacking tray 300, stops the rotation once before pressing the upper surface of the next sheet discharged by the upper discharge roller 230A and the lower discharge roller 230B, and starts the rotation again, so that the sheet pressing paddle 320 presses down the upper surface of the next sheet discharged onto the stacking tray 300 at a rotation speed slower than the fastest rotation speed of the sheet pressing paddle 320 before it was stopped. The specific details will be explained below.

[0122] 36 shows the home position (HP) of the sheet pressure paddle 320. The home position is a position that does not interfere with other members in the space above the stacking tray 300 so that the paddle portion 3203 of the sheet pressure paddle 320 does not become warped. For example, when waiting for a job, the sheet pressure paddle 320 is located at the home position. A flag 321 is provided on the rotation shaft 3201 of the sheet pressure paddle 320, and when the sheet pressure paddle 320 is located at the home position, the flag 321 is detected by the paddle HP sensor SN15.

[0123] Here, since the sheet pressing paddle 320 rotates around the rotation shaft 3201, the paddle portion 3203 passes through the processing tray 220 side. For this reason, as shown in FIG. 36, a recess 3204 through which the paddle portion 3203 can pass when the sheet pressing paddle 320 rotates is formed on the processing tray 220 side. That is, since the sheet pressing paddle 320 rotates around the rotation shaft 3201, it rotates counterclockwise in FIG. 36 from above the stacking tray 300 toward the processing tray 220 side, passes through the processing tray 220 side, and returns to above the stacking tray 300 again. For this reason, at the downstream end of the processing tray 220 in the predetermined direction, at a position corresponding to the sheet pressing paddle 320 in the width direction, a recess 3204 is formed so as to be recessed toward the upstream side in the predetermined direction. Then, the paddle portion 3203 passes through the recess 3204 when the sheet pressing paddle 320 rotates.

[0124] In this embodiment, a moving mechanism 221 (a rack and pinion mechanism in this embodiment) for moving the alignment plate 271A in the width direction is provided inside the processing tray 220. Since the moving mechanism 221 is provided across the width direction, the recess 3204 can only be recessed up to the front of the moving mechanism 221. That is, in this embodiment, the recess 3204 cannot be recessed to an amount corresponding to the length of the sheet pressing paddle 320. Meanwhile, since the paddle portion 3203 of the sheet pressing paddle 320 has elasticity, the paddle portion 3203 passes through the recess 3204 by elastic deformation, as shown in FIG. 40 described later.

[0125] 37 shows the sheet receiving position of the sheet pressure paddle 320. The sheet receiving position is the position of the sheet pressure paddle 320 when receiving a sheet onto the stacking tray 300. When there is no sheet on the stacking tray 300, the sheet receiving position is a position where the paddle portion 3203 of the sheet pressure paddle 320 abuts against the upper surface of the stacking tray 300 in an elastically bent state. On the other hand, when there is a sheet on the stacking tray 300, the sheet receiving position is a position where the paddle portion 3203 of the sheet pressure paddle 320 abuts against the upper surface of the sheet on the stacking tray 300 in an elastically bent state, as shown in FIG.

[0126] 38 to 43, the operation of pressing down the top surface of a sheet discharged onto the stacking tray 300 by the sheet pressing paddle 320 will be described. Here, the operation of pressing down the next second sheet S2 by the sheet pressing paddle 320 will be described in a state in which the first sheet S1 is pressed down on the stacking tray 300 by the sheet pressing paddle 320. In the following description, a case will be described in which a sheet conveyed by the pre-processing rollers 211A, 212A is delivered to the upper discharge rollers 230A and the lower discharge rollers 230B and is discharged directly onto the stacking tray 300 by the upper discharge rollers 230A and the lower discharge rollers 230B, but the operation of the sheet pressing paddle 320 is similar in the case of the discharge operation of the other sheets described above.

[0127] First, Fig. 38 shows a state in which a first sheet S1 stacked on the stacking tray 300 is being pressed down by the sheet pressing paddle 320, and a second sheet S2, which is the sheet next to the first sheet S1, is being transported by the pre-processing rollers 211A and 212A. While the second sheet S2 is being sandwiched and transported between the upper discharge rollers 230A and the lower discharge rollers 230B, the sheet pressing paddle 320 continues to press down the first sheet S1, as shown in Fig. 39. Since the sheet pressing paddle 320 presses down the first sheet S1 in this way, when the second sheet S2 is transported on top of the first sheet S1, it is possible to prevent the first sheet S1 from shifting even if the leading edge of the second sheet abuts against the first sheet S1.

[0128] As shown in Fig. 40, while the second sheet S2 is being sandwiched and conveyed between the upper discharge roller 230A and the lower discharge roller 230B, the sheet pressing paddle 320 starts rotating in the counterclockwise direction in the figure. At this time, the paddle portion 3203 enters the recessed portion 3204 while elastically deforming. Then, as shown in Fig. 41, after the rear end (upstream end in the predetermined direction) of the second sheet S2 passes through the discharge nip portion 230a between the upper discharge roller 230A and the lower discharge roller 230B, the paddle portion 3203 jumps out of the recessed portion 3204 and the rotation accelerates. At this time, the third sheet S3, which is the sheet next to the second sheet S2, is being sandwiched and conveyed between the pre-processing rollers 211A and 212A.

[0129] Next, as shown in Fig. 42, the sheet pressing paddle 320 stops rotating once before the paddle portion 3203 comes into contact with the second sheet S2. That is, the sheet pressing paddle 320 rotates from a state in which it presses the first sheet S1 stacked on the stacking tray 300, and stops rotating once before pressing the upper surface of the next second sheet S2 discharged by the upper discharge roller 230A and the lower discharge roller 230B. The position at which the sheet pressing paddle 320 stops rotating once is a position at which the tip of the paddle portion 3203 does not come into contact with the first sheet S1 stacked on the stacking tray 300 when it sways downstream in the rotation direction due to elasticity when the sheet pressing paddle 320 stops rotating once. That is, since the paddle portion 3203 has elasticity as described above, when the rotation of the sheet pressing paddle 320 is stopped, the tip of the paddle portion 3203 sways downstream in the rotation direction due to elasticity due to inertia. For this reason, in this embodiment, the stop position of the sheet pressing paddle 320 is set taking into consideration the amplitude of the elastic vibration of the paddle portion 3203 .

[0130] On the other hand, as described below, the sheet pressing paddle 320 will stop rotating once and then start rotating again to press down the upper surface of the sheet on the stacking tray 300. Therefore, from the viewpoint of suppressing collision noise, it is not preferable to make the rotation speed of the sheet pressing paddle 320 after restarting rotation too fast. If the position where the sheet pressing paddle 320 stops rotating once is too far from the stacking tray 300, the rotation speed of the sheet pressing paddle 320 after restarting rotation is slow, so it takes time to press down the sheet, and productivity decreases. Therefore, from the viewpoint of productivity, it is preferable to set the position where the sheet pressing paddle 320 stops rotating once as close as possible to the stacking tray 300.

[0131] In this embodiment, the position at which the sheet pressure paddle 320 temporarily stops rotating is a position above the stacking tray 300 where the paddle portion 3203 in a non-elastically deformed state is approximately parallel to the horizontal direction, as shown in Fig. 42. This position can be set appropriately in consideration of the positional relationship between the stacking tray 300 and the rotation shaft 3201 of the sheet pressure paddle 320, the angle of the stacking surface of the stacking tray 300 with respect to the horizontal direction, and the timing at which the sheet pressure paddle 320 temporarily stops rotating preferably satisfies the following points.

[0132] First, the timing at which the sheet pressing paddle 320 temporarily stops rotating is the timing at which the paddle portion 3203 is located upstream in the rotation direction from the contact position where the paddle portion 3203 contacts the upper surface of the stacking tray 300, and is located within a range up to a position 180° upstream in the rotation direction of the contact position. In this embodiment, since the paddle portion 3203 passes through the recessed portion 3204 as described above, if the paddle portion 3203 stops while located within the recessed portion 3204, the rotation is resumed thereafter, and when the paddle portion 3203 protrudes from the recessed portion 3204, an elastic restoration action is performed, which may cause the operation of the sheet pressing paddle 320 to become unstable. For this reason, it is preferable that the timing at which the sheet pressing paddle 320 temporarily stops rotating is at least after the paddle portion 3203 has passed the recessed portion 3204.

[0133] As described above, the rotation shaft 3201 of the sheet pressing paddle 320 is provided coaxially with the rotation shaft 230B1 of the lower discharge roller 230B (see FIG. 5A). Therefore, in this embodiment, it is preferable that the timing at which the sheet pressing paddle 320 temporarily stops rotating is the timing at which the paddle portion 3203 is located downstream in the rotation direction from the nip point between the upper discharge roller 230A and the lower discharge roller 230B. Note that, when a pair of rollers contact each other at a point, the nip point is the point, and when a pair of rollers contact each other with a width in the sheet conveying direction, the nip point is the center position of the width in the sheet conveying direction.

[0134] As described above, after the sheet pressure paddle 320 stops rotating, the sheet pressure paddle 320 starts rotating again. At this time, the sheet pressure paddle 320 rotates at a slower rotation speed than the fastest rotation speed of the sheet pressure paddle 320 before it stopped. Then, as shown in Fig. 43, the sheet pressure paddle 320 presses down the upper surface of the second sheet S2 discharged onto the stacking tray 300. At this time, the next third sheet S3 is being sandwiched and conveyed between the upper discharge roller 230A and the lower discharge roller 230B, and the above-mentioned operations shown in Figs. 39 to 43 are repeated for the third sheet S3 as well.

[0135] The timing for the sheet pressing paddle 320 to stop rotating once and start rotating again is preferably as early as possible after the rotation for productivity has stopped. However, since the paddle portion 3203 has elasticity, if the timing at which the tip of the paddle portion 3203 sways downstream in the rotation direction due to elasticity coincides with the timing at which the sheet pressing paddle 320 resumes rotation, the paddle portion 3203 will come into strong contact with the sheet due to the elasticity of the paddle portion 3203 swaying downstream in the rotation direction, resulting in a loud collision sound.

[0136] Therefore, in this embodiment, when the sheet pressing paddle 320 stops rotating, the tip of the paddle portion 3203 elastically swings downstream in the rotation direction, and then the tip of the paddle portion 3203 elastically swings upstream in the rotation direction. This point will be described with reference to Figures 44(a) to 44(c). First, Figure 44(a) shows a state in which the sheet pressing paddle 320 is rotating to press the sheet S discharged onto the stacking tray 300.

[0137] Next, as shown in Fig. 44(b), when the rotation of the sheet pressing paddle 320 is temporarily stopped, the tip of the paddle portion 3203 is elastically swung downstream in the rotation direction. Thereafter, as shown in Fig. 44(c), the tip of the paddle portion 3203 that has swung downstream in the rotation direction returns in the opposite direction due to the elasticity of the paddle portion 3203, and thus swung upstream in the rotation direction. In this embodiment, the rotation of the sheet pressing paddle 320 is resumed at the timing when the paddle portion 3203 is swung upstream in the rotation direction in this way. Then, after the paddle portion 3203 has swung upstream in the rotation direction, the paddle portion 3203 is made to come into contact with the sheet S on the stacking tray 300 before it starts to swung downstream in the rotation direction again due to its elasticity.

[0138] In this manner, in this embodiment, when the sheet pressure paddle 320 presses down the upper surface of the sheet discharged onto the stacking tray 300, the sheet pressure paddle 320 is operated so that the rotation of the sheet pressure paddle 320 is temporarily stopped and then the sheet pressure paddle 320 starts rotating again at a rotation speed slower than the fastest rotation speed of the sheet pressure paddle 320 before the sheet pressure paddle 320 was temporarily stopped. This makes it possible to prevent the paddle portion 3203 of the sheet pressure paddle 320 from coming into forceful contact with the sheet on the stacking tray 300, thereby reducing the impact noise.

[0139] In addition, since the timing for resuming rotation of the sheet pressing paddle 320 is set to the timing when the paddle portion 3203 is elastically swung toward the upstream side in the rotation direction as described above, it is possible to prevent the paddle portion 3203 from coming into forceful contact with the sheets on the stacking tray 300, compared to the case where rotation is resumed when the paddle portion 3203 is swung toward the downstream side in the rotation direction. This makes it possible to further reduce the collision noise.

[0140] Next, the operation of the sheet pressing paddle 320 of the present embodiment described above will be described in more detail with reference to FIG. 45(a) to FIG. 47(b). First, FIG. 45(a) and (b) show the detection operation of the home position of the sheet pressing paddle 320. As described above, the sheet pressing paddle 320 rotates by driving the take-in motor MT15. In the case of the present embodiment, the take-in motor MT15 is a pulse motor. FIG. 45(a) is a diagram showing the state in which the sheet pressing paddle 320 rotates once at a constant speed. In FIG. 45(a), the locus of the movement of the sheet pressing paddle 320 is shown typically by a circular arc locus. Also, the position of the sheet pressing paddle 320 shown in FIG. 45(a) is the sheet receiving position (i.e., the pressing position) as in FIG. 37, but in FIG. 45(a), the paddle portion 3203 is not elastically deformed as in FIG. 37. FIG. 45(b) is a diagram showing the relationship between the position of the sheet pressing paddle 320, the elapsed time, and the speed (pps) of the take-in motor MT15 at that time.

[0141] When a sheet is received on the stacking tray 300 during a job, the sheet pressing paddle 320 is located at the sheet receiving position shown in FIG. 37. This position is also the position where the sheet is pressed when there is a sheet on the stacking tray 300, so in FIG. 45(b), this position is called the "pressing position." When a home position detection operation is performed, rotation starts from this pressing position. In this embodiment, the take-in motor MT15 rotates once at a constant speed of, for example, 600 pps during a home position detection operation. At this time, the home position is detected when a flag 321 provided on the rotating shaft 3201 passes the paddle HP sensor SN15.

[0142] 46(a) and (b) show the operation when the sheet pressure paddle 320 is moved from the home position to the pressing position. FIG. 46(a) is a diagram showing the state in which the sheet pressure paddle 320 rotates from the home position to the pressing position. FIG. 46(a) shows the path along which the sheet pressure paddle 320 moves, as a circular arc path. FIG. 46(a) also shows the state in which the sheet pressure paddle 320 is in the sheet receiving position (i.e., the pressing position) without elastically deforming the paddle portion 3203, as in FIG. 45(a). FIG. 46(b) is a diagram showing the relationship between the position of the sheet pressure paddle 320, the elapsed time, and the speed (pps) of the take-in motor MT15 at that time.

[0143] The operation of the sheet pressure paddle 320 moving from the home position to the pressing position is performed, for example, when a job including an operation of discharging a plurality of sheets to the stacking tray 300 is executed, before the first sheet of the job is discharged to the stacking tray 300. In this embodiment, the rotation operation of the sheet pressure paddle 320 is performed by first accelerating the rotation speed of the sheet pressure paddle 320 to a first speed (maximum speed in this embodiment), and then decelerating from the first speed to a second speed to temporarily stop the rotation of the sheet pressure paddle 320. The position and timing of the temporary stop are as described above. Then, the sheet pressure paddle 320 is moved to the pressing position at the second speed lower than the first speed. At this position, the sheet is waited for to be discharged to the stacking tray 300.

[0144] Specifically, the rotation of the sheet pressure paddle 320 is accelerated to 1000 pps from the home position to an angle of 2.25°, and then the sheet pressure paddle 320 is rotated at a constant speed of 1000 pps for an angle of 37.5°. Then, the rotation of the sheet pressure paddle 320 is decelerated from 1000 pps to 600 pps for the angle of 2.25°, and the rotation of the sheet pressure paddle 320 is temporarily stopped. Then, the rotation of the sheet pressure paddle 320 is resumed and rotated at a constant speed of 600 pps for an angle of 108°. As a result, the sheet pressure paddle 320 is located at the pressing position. At this time, the rotation of the sheet pressure paddle 320 is temporarily stopped, and the sheet pressure paddle 320 comes into contact with the upper surface of the stacking tray 300 at a second low speed, thereby reducing the impact sound.

[0145] The amount of movement of the sheet pressure paddle 320 when it moves from the home position to the pressing position is smaller than the amount of movement when it makes one revolution from the pressing position and returns to the pressing position again. For this reason, the movement of the sheet pressure paddle 320 at this time may be performed without stopping the rotation. At this time, it is moved from the home position to the pressing position at the second speed. In this case, the time required to move the sheet pressure paddle 320 from the home position to the pressing position becomes long, but the timing of moving the sheet pressure paddle 320 from the home position to the pressing position is the start of a job, which is a stage before the sheet is discharged to the stacking tray 300, so there is plenty of time. Therefore, even if it takes time at this time, there is almost no impact on productivity.

[0146] 47(a) and (b) show the operation when the sheet pressing paddle 320 rotates once from the pressing position and moves to the pressing position again in order to press the upper surface of the sheet discharged to the stacking tray 300. FIG. 47(a) is a diagram showing the state in which the sheet pressing paddle 320 rotates once from the pressing position. FIG. 47(a) shows the path of the sheet pressing paddle 320 moving as a circular arc path. Also, FIG. 47(a) shows the state in which the sheet pressing paddle 320 is in the sheet receiving position (i.e., the pressing position) without elastically deforming the paddle portion 3203, similar to FIG. 45(a). FIG. 47(b) is a diagram showing the relationship between the position of the sheet pressing paddle 320 at that time, the elapsed time, and the speed (pps) of the take-in motor MT15.

[0147] The operation of the sheet pressing paddle 320 rotating once from the pressing position is performed, for example, when a job including an operation of discharging a plurality of sheets to the stacking tray 300 is executed and the first and subsequent sheets of the job are discharged to the stacking tray 300. In this embodiment, the rotation operation of the sheet pressing paddle 320 starts at a low second speed, and then accelerates the rotation speed to a first speed (maximum speed in this embodiment). This is because, as described above, the sheet pressing paddle 320 also functions as a discharged sheet pick-up paddle. That is, the sheet pressing paddle 320 performs an operation of picking up the sheet on the stacking tray 300 toward the upright surface 310a (FIG. 2). At this time, if the rotation speed of the sheet pressing paddle 320 is high, there is a risk that the sheet may be damaged by buckling or the like. Alternatively, when the paddle portion 3203 separates from the sheet, the strain stored in the sheet is released, and the sheet moves in a direction away from the standing surface 310a, which may affect the alignment of the sheet.

[0148] The reason why the sheet pressure paddle 320 starts rotating at the low second speed and then at the high first speed is also because the paddle portion 3203 passes through the recessed portion 3204 when the sheet pressure paddle 320 is rotated from the pressing position. That is, if the sheet pressure paddle 320 is rotated at the high first speed when the paddle portion 3203 passes through the recessed portion 3204, a large load is applied to the paddle portion 3203 due to friction with the recessed portion 3204. For this reason, in this embodiment, the sheet pressure paddle 320 starts rotating at the low second speed, and the sheet pressure paddle 320 is rotated at the second speed until the paddle portion 3203 is partway through passing through the recessed portion 3204, and the rotation of the sheet pressure paddle 320 is accelerated before the paddle portion 3203 comes out of the recessed portion 3204.

[0149] Next, after rotating at a first speed, the rotation of the sheet pressing paddle 320 is decelerated from the first speed to a second speed and temporarily stopped. The position and timing of the temporary stop are as described above. Then, the sheet pressing paddle 320 is moved to the pressing position at the second speed, which is lower than the first speed. As a result, the upper surface of the sheet discharged onto the stacking tray 300 is pressed by the sheet pressing paddle 320.

[0150] Specifically, the sheet pressure paddle 320 is rotated at a constant speed of 600 pps from the pressing position to an angle of 10°, and then the rotation speed of the sheet pressure paddle 320 is accelerated to 1000 pps until the angle reaches 2.25°. Then, the sheet pressure paddle 320 is rotated at a constant speed of 1000 pps for an angle of 237.5°. Next, the rotation speed of the sheet pressure paddle 320 is decelerated from 1000 pps to 600 pps for an angle of 2.25°, and then the rotation of the sheet pressure paddle 320 is temporarily stopped. In this embodiment, the rotation of the sheet pressure paddle 320 is stopped for a predetermined time (30 ms in the illustrated example). The time for which the rotation of the sheet pressure paddle 320 is temporarily stopped varies depending on the length and hardness of the sheet pressure paddle 320. Then, the rotation of the sheet pressure paddle 320 is resumed and rotated at a constant speed of 600 pps for an angle of 108°. As a result, the sheet pressing paddle 320 is located at the pressing position. At this time, the sheet pressing paddle 320 is temporarily stopped from rotating, and then comes into contact with the upper surface of the stacking tray 300 at a second slow speed, thereby reducing the impact noise.

[0151] In the above description, the rotation of the sheet pressing paddle 320 is temporarily stopped from the operation for the first sheet of the job, but for the first sheet, the sheet pressing paddle 320 may be rotated at a low speed (for example, the second speed) without stopping the rotation, so that the sheet pressing paddle 320 presses the top surface of the sheet. That is, unlike the second and subsequent sheets, the first sheet is not pressed before the sheet pressing operation, so there is ample time until the sheet pressing paddle 320 presses the top surface. Therefore, for the first sheet, for example, the start timing of the rotation of the sheet pressing paddle 320 can be made earlier than the operation for the second and subsequent sheets. Therefore, the first sheet can be pressed by rotating the sheet pressing paddle 320 at a constant speed at the second speed, and if the paddle portion 3203 abuts against the top surface of the sheet at a low speed, the collision sound is reduced.

[0152] On the other hand, for the second and subsequent sheets, as described in FIG. 38 to FIG. 43, it is necessary to perform the sheet pressing operation by the sheet pressing paddle 320 so as to be in time with the conveying timing of the successively conveyed sheets. For this reason, if the sheet pressing paddle 320 is rotated at a constant speed by the second speed as in the case of the first sheet, the pressing operation of the next sheet will not be in time. In this case, it is conceivable to widen the sheet conveying interval so as to be in time with the pressing operation of the next sheet, but this would result in a decrease in productivity. Therefore, in this embodiment, the sheet pressing paddle 320 is operated as described above for at least the second and subsequent sheets of the job, that is, the next sheet when sheets are already stacked on the stacking tray 300.

[0153] That is, when the sheet pressing paddle 320 rotates from a state in which it presses down the sheets stacked on the stacking tray 300, it accelerates the rotation speed to a first speed, then decelerates the rotation speed from the first speed to a second speed, stops the rotation, and rotates at the second speed to press down the top surface of the next sheet discharged to the stacking tray 300. This makes it possible to suppress a decrease in productivity while reducing the impact noise. It is preferable that the deceleration rate from the first speed to the second speed is set to a rate that allows a large speed difference within a range in which the plastic deformation of the paddle portion 3203 is not promoted as the speed is decelerated from the first speed to the second speed. That is, if the plastic deformation of the paddle portion 3203 increases due to the acceleration of the deceleration, the convergence time of the vibration of the paddle portion 3203 at the time of stopping becomes longer. On the other hand, if the speed difference between the first speed and the second speed is large, the stop time of the sheet pressure paddle 320 can be made long, but if the speed difference is large, the vibration of the paddle portion 3203 is difficult to converge. In the case of this embodiment, the deceleration rate from the first speed to the second speed is preferably, for example, 60% or more and 80% or less. If the second speed is less than 60% of the first speed, the rotation speed of the sheet pressure paddle 320 becomes too slow, which reduces productivity. On the other hand, if the second speed is more than 80% of the first speed, the rotation speed of the sheet pressure paddle 320 is too fast, which may not reduce the impact noise sufficiently.

[0154] <Second embodiment> The second embodiment will be described with reference to Fig. 48(a) to Fig. 49(b). In the above-mentioned first embodiment, an example was described in which the rotation of the sheet pressing paddle 320 was temporarily stopped when pressing down the upper surface of the sheet on the stacking tray 300. In contrast, in this embodiment, the rotation of the sheet pressing paddle 320 is not stopped but is slowed down when pressing down the upper surface of the sheet on the stacking tray 300. Since other configurations and functions are similar to those of the above-mentioned first embodiment, the same reference numerals are used for similar configurations, and illustrations and descriptions are omitted or simplified, and the following description will focus on the points that are different from the first embodiment.

[0155] There is a higher-speed image forming system. In this case, the sheet conveying interval becomes shorter, so if the rotation of the sheet pressing paddle 320 is stopped once as in the first embodiment, there is a risk that the pressing operation of the next sheet will not be completed in time. Therefore, in this embodiment, the rotation of the sheet pressing paddle 320 is not stopped once, but is only slowed down to reduce the impact noise. That is, the sheet pressing paddle 320 rotates from a state in which it is pressing the sheets stacked on the stacking tray 300, and then the rotation speed is slowed down from a first speed to a second speed before pressing the top surface of the next sheet discharged by the upper discharge roller 230A and the lower discharge roller 230B, and then the top surface of the next sheet discharged on the stacking tray 300 is pressed.

[0156] 48(a) and (b) show the operation when the sheet pressure paddle 320 is moved from the home position to the pressing position. FIG. 48(a) is a diagram showing the state in which the sheet pressure paddle 320 rotates from the home position to the pressing position. FIG. 48(a) shows the path along which the sheet pressure paddle 320 moves, as a circular arc path. FIG. 48(a) also shows the state in which the sheet pressure paddle 320 is in the sheet receiving position (i.e., the pressing position) without elastically deforming the paddle portion 3203, as in FIG. 45(a). FIG. 48(b) is a diagram showing the relationship between the position of the sheet pressure paddle 320, the elapsed time, and the speed (pps) of the take-in motor MT15 at that time.

[0157] The operation of the sheet pressing paddle 320 moving from the home position to the pressing position is performed, for example, when a job including an operation of discharging a plurality of sheets to the stacking tray 300 is executed, before the first sheet of the job is discharged to the stacking tray 300. In this embodiment, the rotation operation of the sheet pressing paddle 320 is performed by first accelerating the rotation speed of the sheet pressing paddle 320 to a first speed (maximum speed in this embodiment) and then decelerating from the first speed to a second speed. The timing of decelerating from the first speed to the second speed is the same as the timing of temporarily stopping the rotation of the sheet pressing paddle 320 in the first embodiment. Then, the sheet pressing paddle 320 is moved to the pressing position at a second speed lower than the first speed. At this position, the sheet is waited for to be discharged to the stacking tray 300.

[0158] Specifically, the rotation of the sheet pressure paddle 320 is accelerated to 1000 pps from the home position to an angle of 2.25°, and then the sheet pressure paddle 320 is rotated at a constant speed of 1000 pps for an angle of 37.5°. Then, the rotation of the sheet pressure paddle 320 is decelerated from 1000 pps to 600 pps for the angle of 2.25°. Then, the sheet pressure paddle 320 is rotated at a constant speed of 600 pps for an angle of 108°. As a result, the sheet pressure paddle 320 is positioned at the pressing position. At this time, the sheet pressure paddle 320 comes into contact with the upper surface of the stacking tray 300 at a low second speed, so that the collision sound is reduced. Note that when moving from the home position to the pressing position, the sheet pressure paddle 320 may be rotated at a constant speed at the second speed.

[0159] 49(a) and (b) show the operation when the sheet pressing paddle 320 rotates once from the pressing position and moves to the pressing position again in order to press the upper surface of the sheet discharged to the stacking tray 300. FIG. 49(a) is a diagram showing the state in which the sheet pressing paddle 320 rotates once from the pressing position. FIG. 49(a) shows the path of the sheet pressing paddle 320 moving as a circular arc path. Also, FIG. 49(a) shows the state in which the sheet pressing paddle 320 is in the sheet receiving position (i.e., the pressing position) without elastically deforming the paddle portion 3203, similar to FIG. 45(a). FIG. 49(b) is a diagram showing the relationship between the position of the sheet pressing paddle 320 at that time, the elapsed time, and the speed (pps) of the take-in motor MT15.

[0160] The operation of the sheet pressure paddle 320 making one rotation from the pressing position is performed, for example, when a job including an operation of discharging a plurality of sheets onto the stacking tray 300 is executed and the first and subsequent sheets of the job are discharged onto the stacking tray 300. In this embodiment, the rotation operation of the sheet pressure paddle 320 first starts the sheet pressure paddle 320 rotating at a low second speed, and then accelerates the rotation speed to a first speed (maximum speed in this embodiment).

[0161] Next, after rotating at a first speed, the speed is decelerated from the first speed to a second speed. The timing of decelerating from the first speed to the second speed is the same as the timing of temporarily stopping the rotation of the sheet pressure paddle 320 in the first embodiment. Then, the sheet pressure paddle 320 is moved to the pressing position at a second speed lower than the first speed. As a result, the sheet pressure paddle 320 presses down the upper surface of the sheet discharged onto the stacking tray 300.

[0162] Specifically, the sheet pressure paddle 320 is rotated at a constant speed of 600 pps from the pressing position to an angle of 10°, and then the rotation speed of the sheet pressure paddle 320 is accelerated to 1000 pps until the angle reaches 2.25°. Then, the sheet pressure paddle 320 is rotated at a constant speed of 1000 pps for an angle of 237.5°. Next, the rotation speed of the sheet pressure paddle 320 is decelerated from 1000 pps to 600 pps for an angle of 2.25°. Then, the sheet pressure paddle 320 is rotated at a constant speed of 600 pps for an angle of 108°. As a result, the sheet pressure paddle 320 is positioned at the pressing position. At this time, the sheet pressure paddle 320 comes into contact with the upper surface of the stacking tray 300 at a low second speed, so that the collision sound is reduced.

[0163] In the above description, the rotation of the sheet pressure paddle 320 is decelerated from the operation for the first sheet of the job. However, for the first sheet, the rotation of the sheet pressure paddle 320 may not be decelerated, but the sheet pressure paddle 320 may be rotated at a low speed (e.g., a second speed) so that the sheet pressure paddle 320 presses down the top surface of the sheet.

[0164] On the other hand, for the second and subsequent sheets, as described in FIG. 38 to FIG. 43, it is necessary to perform the sheet pressing operation by the sheet pressing paddle 320 so as to be in time with the conveying timing of the successively conveyed sheets. For this reason, if the sheet pressing paddle 320 is rotated at a constant speed by the second speed as in the case of the first sheet, the pressing operation of the next sheet will not be in time. In this case, it is conceivable to widen the sheet conveying interval so as to be in time with the pressing operation of the next sheet, but this would result in a decrease in productivity. Therefore, in this embodiment, the sheet pressing paddle 320 is operated as described above for at least the second and subsequent sheets of the job, that is, the next sheet when sheets are already stacked on the stacking tray 300.

[0165] That is, when the sheet pressing paddle 320 rotates from a state in which it is pressing down a sheet stacked on the stacking tray 300, the rotation speed is accelerated to a first speed, and then the rotation speed is decelerated from the first speed to a second speed, and the sheet pressing paddle 320 rotates at the second speed to press down the top surface of the next sheet discharged onto the stacking tray 300. This makes it possible to reduce the impact noise while suppressing a decrease in productivity. The rate of deceleration from the first speed to the second speed is the same as in the first embodiment.

[0166] <Third embodiment> The third embodiment will be described with reference to Fig. 50. In the above-mentioned embodiments, the sheet processing apparatus 200 including the staple unit 400 has been described, but the present invention is also applicable to a sheet processing apparatus 200A not including the staple unit 400 as shown in Fig. 50.

[0167] The image forming system 1000A shown in Fig. 50 includes an image forming apparatus 100A and a sheet processing apparatus 200A as a sheet stacking apparatus. The image forming apparatus 100 shown in Fig. 1 is a full-color image forming apparatus, and the sheet processing apparatus 200 is disposed in the internal space 130. In contrast, the image forming apparatus 100A of the present embodiment is a monochrome image forming apparatus having one image forming station, and the sheet processing apparatus 200A as a sheet stacking apparatus is connected to the downstream side of the image forming apparatus 100A in the sheet conveying direction. The basic configuration of the image forming apparatus 100A of the present embodiment is the same as that of the image forming apparatus 100 of Fig. 1, and therefore a detailed description thereof will be omitted.

[0168] The sheet processing apparatus 200A shown in FIG. 50 has a shift device 410 that performs only a shift process to shift a sheet in the width direction. The shift device 410 has the same configuration as a conventionally known configuration, but in the illustrated example, a pair of rollers 412 that conveys a sheet in a straight path 411 can move in the width direction while holding the sheet. The sheet that has been moved in the width direction (shifted) by the pair of rollers 412 is discharged from the pair of rollers 412 that also functions as a discharge section to a stacking tray 300A as a stacking section. In this embodiment, the upper surface of the sheet discharged to the stacking tray 300A by the pair of rollers 412 is pressed by a sheet pressing paddle 320A as a pressing member, as in each of the above-mentioned embodiments.

[0169] The sheet pressing paddle 320A rotates about a rotation axis provided coaxially with the rotation axis of the lower roller 412A of the roller pair 412. Similarly to the above-mentioned embodiments, the sheet pressing paddle 320A, when pressing the upper surface of the sheet, stops rotating once or slows down the rotation before pressing the upper surface of the sheet discharged onto the stacking tray 300A. In short, the present invention is applicable not only to the sheet processing apparatus 200 shown in FIG. 1 but also to a configuration such as the sheet processing apparatus 200A shown in FIG. 50 that does not include a staple unit, in which a sheet is discharged onto a stacking tray and the upper surface of the discharged sheet is pressed by a pressing member such as a rotating sheet pressing paddle.

[0170] <Other embodiments> In each of the above-described embodiments, the sheet processing device 200, 200A is arranged in the internal space 130 of the image forming apparatus 100, but the sheet processing device of the present invention may be, for example, attached to the side of the image forming apparatus. Also, the sheet processing device may be controlled by a control unit included in the image forming apparatus.

[0171] The disclosure of this embodiment also includes the following configuration. (Configuration 1) A loading section for loading sheets; a discharge section that discharges a sheet to the stacking section; a rotation shaft located on a lower surface side of the sheet being discharged by the discharge unit; a pressing member having a fixed portion fixed to the rotating shaft and an elastic contact portion provided on the fixed portion, the pressing member rotating about the rotating shaft to press an upper surface of the sheet discharged to the stacking portion with the contact portion; a drive unit that rotates the pressure member from a state in which it is pressing down on a sheet loaded on the stacking section, stops the rotation temporarily before pressing down on the top surface of the next sheet to be discharged by the discharge section, and then starts the rotation again, thereby driving the pressure member to press down on the top surface of the next sheet discharged to the stacking section at a rotational speed slower than the fastest rotational speed of the pressure member before the temporary stop. (Configuration 2) The timing at which the pressing member stops rotating and starts rotating again is the timing at which the tip of the contact portion elastically swings downstream in the direction of rotation when the pressing member stops rotating, and then the tip elastically swings upstream in the direction of rotation. (Configuration 3) A sheet stacking device as described in configuration 1 or 2, in which the position at which the pressing member temporarily stops rotating is a position at which the tip of the contact portion does not come into contact with the sheets loaded in the loading section when the pressing member temporarily stops rotating and the tip of the contact portion elastically swings downstream in the rotation direction. (Configuration 4) The timing at which the pressing member temporarily stops rotating is the timing at which the contact portion is located upstream of the contact position where the contact portion contacts the upper surface of the stacking portion, within a range of up to a position 180° upstream of the contact position in the rotational direction. (Configuration 5) The discharge section is a pair of discharge rollers that sandwich and transport a sheet, the rotation shaft is coaxial with the rotation shaft of the lower roller of the pair of discharge rollers, The sheet stacking device according to configuration 3, wherein the pressing member temporarily stops rotating when the contact portion is located downstream of a nip point between the pair of discharge rollers in a rotation direction. (Configuration 6) A sheet stacking device described in any one of configurations 1 to 5, wherein when rotating the pressing member from a state pressing down on a sheet loaded on the stacking section, the drive section accelerates the rotation speed to a first speed, then decelerates the rotation speed from the first speed to a second speed, stops the rotation, and rotates at the second speed to press down on the top surface of the next sheet discharged to the stacking section. (Configuration 7) A conveying unit that conveys the sheet in a predetermined direction; a placement section for placing the sheet conveyed in the predetermined direction by the conveying section; A processing unit that performs a binding process on a sheet bundle from the plurality of sheets placed on the placement unit, A sheet stacking device according to any one of configurations 1 to 6, wherein the discharge section is capable of discharging a sheet stack that has been bound by the processing section and a sheet that has been transported in the specified direction by the transport section to the stacking section. (Configuration 8) A loading section for loading sheets; a discharge section that discharges a sheet to the stacking section; a rotation shaft located on a lower surface side of the sheet being discharged by the discharge unit; a pressing member having a fixed portion fixed to the rotating shaft and an elastic contact portion provided on the fixed portion, the pressing member rotating about the rotating shaft to press an upper surface of the sheet discharged to the stacking portion with the contact portion; a drive section that rotates the pressing member from a state in which the pressing member is pressing a sheet loaded on the stacking section, decelerates the rotational speed from a first speed to a second speed before pressing the top surface of the next sheet discharged by the discharge section, and then drives the pressing member to press the top surface of the next sheet discharged to the stacking section. (Configuration 9) A sheet stacking device as described in configuration 8, wherein the timing at which the pressing member starts to decelerate its rotational speed from the first speed is the timing at which the contact portion is located upstream in the rotational direction from a contact position where the contact portion contacts the upper surface of the stacking portion, and within a range up to a position 180° upstream in the rotational direction from the contact position. (Configuration 10) The discharge section is a pair of discharge rollers that sandwich and transport a sheet, the rotation shaft is coaxial with the rotation shaft of the lower roller of the pair of discharge rollers, The sheet stacking device according to configuration 9, wherein the timing at which the pressing member starts to reduce the rotational speed from the first speed is the timing at which the contact portion is located downstream in the rotational direction from a nip point of the pair of discharge rollers. (Configuration 11) A conveying unit that conveys the sheet in a predetermined direction; a placement section for placing the sheet conveyed in the predetermined direction by the conveying section; A processing unit that performs a binding process on a sheet bundle from the plurality of sheets placed on the placement unit, A sheet stacking device according to any one of configurations 8 to 10, wherein the discharge section is capable of discharging a sheet stack that has been bound by the processing section and a sheet that has been transported in the specified direction by the transport section to the stacking section. (Configuration 12) an image forming apparatus having an image forming unit that forms an image on a sheet; The sheet stacking device according to any one of configurations 1 to 11, The sheet stacking device is an image forming system that stacks, on the stacking section, sheets on which images have been formed by the image forming section. [Explanation of symbols]

[0172] 100, 100A...Image forming device 103... Image forming unit 200, 200A...Sheet processing device (sheet stacking device) 211A, 212A: Pre-processing rollers (first conveying section, pair of conveying rotating bodies) 220 Processing tray (mounting section) 230A···Upper discharge roller (discharge section, discharge rotor) 230B: Lower discharge roller (discharge section, discharge rotor) 230B1 Rotating shaft 300, 300A··· Loading tray (loading section) 320, 320A... Sheet holding paddle (holding member) 400··· Staple unit (processing section) 1000, 1000A... Image formation system 3201 Rotating shaft 3202...Fixed part 3203 Paddle part (contact part) MT15···Screwing motor (drive unit)

Claims

1. A loading section for loading sheets; a discharge section that discharges a sheet to the stacking section; a rotation shaft located on a lower surface side of the sheet being discharged by the discharge unit; a pressing member having a fixed portion fixed to the rotating shaft and an elastic contact portion provided on the fixed portion, the pressing member rotating about the rotating shaft to press an upper surface of the sheet discharged to the stacking portion with the contact portion; a drive unit that rotates the pressure member from a state in which it is pressing down on a sheet loaded on the stacking section, stops the rotation temporarily before pressing down on the top surface of the next sheet to be discharged by the discharge section, and then starts the rotation again, thereby driving the pressure member to press down on the top surface of the next sheet discharged to the stacking section at a rotational speed slower than the fastest rotational speed of the pressure member before the temporary stop.

2. The timing at which the pressing member stops rotating and starts rotating again is the timing at which the tip of the contact portion elastically swings downstream in the direction of rotation when the pressing member stops rotating, and then the tip elastically swings upstream in the direction of rotation.

3. The sheet stacking device of claim 1, wherein the position at which the pressing member temporarily stops rotating is a position at which the tip of the contact portion does not come into contact with the sheets stacked in the stacking section when the pressing member temporarily stops rotating and the tip of the contact portion elastically swings downstream in the rotation direction.

4. The sheet stacking device of claim 3, wherein the timing at which the pressing member temporarily stops rotating is the timing at which the contact portion is located upstream of the contact position where the contact portion contacts the upper surface of the stacking portion, within a range of up to a position 180° upstream of the contact position in the rotational direction.

5. The discharge section is a pair of discharge rollers that sandwich and transport a sheet, the rotation shaft is coaxial with the rotation shaft of the lower roller of the pair of discharge rollers, 4. The sheet stacking device according to claim 3, wherein the pressing member temporarily stops rotating when the contact portion is located downstream of a nip point between the pair of discharge rollers in a rotational direction.

6. 2. The sheet stacking device according to claim 1, wherein when the pressing member is rotated from a state in which it is pressing down on a sheet loaded on the stacking section, the drive section accelerates the rotation speed to a first speed, then decelerates the rotation speed from the first speed to a second speed, then stops the rotation, and then rotates at the second speed to press down on the top surface of the next sheet discharged to the stacking section.

7. A conveying unit that conveys the sheet in a predetermined direction; a placement section for placing the sheet conveyed in the predetermined direction by the conveying section; A processing unit that performs a binding process on a sheet bundle from the plurality of sheets placed on the placement unit, The sheet stacking device according to claim 1 , wherein the discharge section is capable of discharging the sheet bundle bound by the processing section and the sheet transported in the predetermined direction by the transport section onto the stacking section.

8. A loading section for loading sheets; a discharge section that discharges a sheet to the stacking section; a rotation shaft located on a lower surface side of the sheet being discharged by the discharge unit; a pressing member having a fixed portion fixed to the rotating shaft and an elastic contact portion provided on the fixed portion, the pressing member rotating about the rotating shaft to press an upper surface of the sheet discharged to the stacking portion with the contact portion; a drive section that rotates the pressing member from a state in which the pressing member is pressing a sheet loaded on the stacking section, decelerates the rotational speed from a first speed to a second speed before pressing the top surface of the next sheet discharged by the discharge section, and then drives the pressing member to press the top surface of the next sheet discharged to the stacking section.

9. A sheet stacking device as described in claim 8, wherein the timing at which the pressing member starts to decelerate its rotational speed from the first speed is the timing at which the contact portion is located upstream in the rotational direction from the contact position where the contact portion contacts the upper surface of the stacking portion, and within a range up to a position 180° upstream in the rotational direction of the contact position.

10. The discharge section is a pair of discharge rollers that sandwich and transport a sheet, the rotation shaft is coaxial with the rotation shaft of the lower roller of the pair of discharge rollers, 10. The sheet stacking device according to claim 9, wherein the pressing member starts to reduce the rotation speed from the first speed when the contact portion is located downstream of a nip point between the pair of discharge rollers in the rotation direction.

11. A conveying unit that conveys the sheet in a predetermined direction; a placement section for placing the sheet conveyed in the predetermined direction by the conveying section; A processing unit that performs a binding process on a sheet bundle from the plurality of sheets placed on the placement unit, The sheet stacking device according to claim 8 , wherein the discharge section is capable of discharging the sheet bundle bound by the processing section and the sheet transported in the predetermined direction by the transport section onto the stacking section.

12. an image forming apparatus having an image forming unit that forms an image on a sheet; The sheet stacking device according to any one of claims 1 to 11, The sheet stacking device is an image forming system that stacks, on the stacking section, sheets on which images have been formed by the image forming section.

Images