Sheet processing device and image formation system

Abstract

A restriction part abuts on the back of a sheet bundle when moved from an initial position to a restriction position, thereby restricting the amount by which the sheet bundle projects from a position of being clamped by a clamp. An adjustment part adjusts the initial position of the restriction part with respect to the clamp position in advance each time corner back processing is performed.

Description

Sheet processing apparatus and image forming system

[0001] The present disclosure relates to a sheet processing apparatus that performs square spine processing on a sheet stack, and an image forming system that includes the sheet processing apparatus.

[0002] There is a sheet processing device that performs a process of forming a corner on the spine of a sheet bundle (hereinafter referred to as "square spine processing") by clamping a folded sheet bundle with a pair of clamps and pressing the spine of the sheet bundle that protrudes beyond the clamps while moving a roller. Patent Document 1 discloses a configuration that performs square spine processing by providing a regulating unit that abuts the spine of the sheet bundle to regulate the amount of protrusion of the sheet bundle from the clamp, and pressing the spine of the sheet bundle that protrudes by an amount determined by the regulating unit.

[0003] JP 2009-227449 A

[0004] However, in the case of the configuration of Patent Document 1, the positions of the restricting portion and the clamping portion may be misaligned due to variations in product tolerances, etc. In this case, even if the restricting portion is moved to the restricting position, there is a risk that the restricting portion will not move to the intended position. Therefore, there is a possibility that the back corner processing will not be performed properly.

[0005] The present disclosure provides a configuration for improving the positional accuracy of a regulating portion that regulates the amount of protrusion of the spine of a sheet stack from a clamp portion.

[0006] One aspect of the present disclosure is a sheet processing device including: a conveying unit that conveys a folded sheet stack with a crease bound; a clamping unit that clamps the sheet stack conveyed by the conveying unit at a clamping position; and a pressing unit that presses the sheet stack, and the sheet processing device performs a square spine processing on the spine of the sheet stack clamped by the clamping unit by moving the pressing unit along the crease of the sheet stack; a regulating unit that restricts the amount by which the sheet stack protrudes from the clamping position by hitting the spine of the sheet stack when moving from an initial position to a regulating position; and an adjusting unit that pre-adjusts the initial position of the regulating unit relative to the clamping position each time the square spine processing is performed.

[0007] According to the present disclosure, it is possible to improve the positional accuracy of a regulating portion that regulates the amount of protrusion of the spine of a sheet bundle from a clamp when performing square spine processing on the sheet bundle.

[0008] 1 is a schematic cross-sectional view of an image forming system according to an embodiment; a schematic cross-sectional view of a sheet processing device according to an embodiment; a control block diagram of an image forming system according to an embodiment; an enlarged cross-sectional view of a saddle unit according to an embodiment; a front view of a square spine processing unit according to an embodiment; a perspective view of a square spine processing unit according to an embodiment; a cross-sectional view of a square spine processing unit according to an embodiment; a perspective view of the square spine processing unit according to an embodiment, seen from the front side; a perspective view of the square spine processing unit according to an embodiment, seen from the rear side; a perspective view of a square spine processing unit and a part of a drive unit according to an embodiment; a perspective view of the square spine processing unit and the vicinity of a clamp unit according to an embodiment; a cross-sectional view of a square spine processing unit and a clamp unit according to an embodiment; a diagram for explaining a skew correction unit according to an embodiment; a perspective view of the skew correction unit, showing a state in which a contact unit is located at a retracted position in an embodiment; a view of the skew correction unit, seen from the downstream side in the conveying direction of a sheet bundle, showing a state in which a contact unit is located at a retracted position in an embodiment; a schematic cross-sectional view of the skew correction unit, showing a state in which a contact unit is located at a retracted position in an embodiment; 1 is a perspective view of a skew correction unit showing a state in which a contact portion is lifted in an embodiment; FIG. 2 is a view showing a state in which a contact portion is lifted in an embodiment, showing the skew correction unit as viewed from the downstream side in the conveying direction of a sheet bundle; FIG. 3 is a schematic cross-sectional view of a skew correction unit showing a state in which a contact portion is lifted in an embodiment; FIG. 4 is a perspective view of a skew correction unit showing a state in which a contact member has moved in a direction approaching a clamp unit in an embodiment; FIG. 5 is a schematic cross-sectional view of a skew correction unit showing a state in which a contact member has moved in a direction approaching a clamp unit in an embodiment; FIG. 6 is a view showing a state in which a reference position of a contact member is adjusted to match a lower clamp unit and an upper clamp unit in the operation of adjusting the reference position of a contact member and performing a skew correction process in an embodiment; FIG. 7 is a view showing a state in which a contact member has moved from an adjusted position to a contact position in the operation of adjusting the reference position of a contact member and performing a skew correction process in an embodiment; FIG. 8 is a view showing a state in which a contact member has moved to a contact position and accepted a sheet bundle in the operation of adjusting the reference position of a contact member and performing a skew correction process in an embodiment. 10A and 10B are diagrams illustrating a state in which the contact member has moved from the contact position toward the lower clamp unit and the upper clamp unit in the operation of adjusting the reference position of the contact member and performing the skew correction process in the embodiment.1 is a schematic diagram showing a state in which conveyance of a sheet bundle is stopped by a clamp unit in an operation of square spine processing in an embodiment. 2 is a schematic diagram showing a state in which a sheet bundle is clamped in an operation of square spine processing in an embodiment. 3 is a schematic diagram showing a state in which square spine processing is being performed on a sheet bundle in an operation of square spine processing in an embodiment. 4 is a schematic diagram showing a state in which the clamp of the sheet bundle is released in an operation of square spine processing in an embodiment. 5 is a flowchart showing an example of control of skew correction processing and square spine processing according to an embodiment.

[0009] The embodiment will be described with reference to Figures 1 to 17. First, the schematic configuration of an image forming system according to the embodiment will be described with reference to Figure 1.

[0010] [Image Forming System] In this embodiment, a copier is used as the image forming apparatus. A sheet processing device is connected to the sheet discharge port of the copier, and the sheet processing device further includes a saddle unit that performs saddle stitching and center folding. The image forming system 1000 includes an image forming apparatus A and a sheet processing apparatus B. The downstream sheet processing apparatus B receives a sheet S on which an image is formed by the image forming apparatus A, performs saddle stitching, center folding, and square spine processing as necessary, and then discharges the sheet to a downstream discharge unit. The image forming apparatus A includes various types of devices, such as copiers, printers, printing machines, facsimiles, and multifunction devices that combine these functions. The image forming apparatus A and the sheet processing apparatus B will be described in detail below. In the following description, the side of the image forming apparatus A and the sheet processing apparatus B where a user or other operator operates the device (e.g., the side with an operation panel and operation buttons) will be referred to as the front side (the side facing the paper in FIGS. 1 and 2 ), and the side opposite the front side will be referred to as the rear side (the side facing the paper in FIGS. 1 and 2 ).

[0011] 1, the image forming apparatus A includes an image forming unit A1, an image reading unit A2, and a document feeding unit A3. The image forming unit A1 includes a feeding section 2, an image forming section 3, a discharge section 4, and a data processing section 5 within a housing 1.

[0012] The feeding unit 2 includes multiple cassettes 2a, 2b, and 2c, each of which can store sheets S of different preselected standard sizes in multiple stages. The sheets S are, for example, paper or plastic sheets. Each cassette 2a, 2b, and 2c is provided with a separation mechanism that separates the sheets S stored therein one by one and a feeding mechanism that dispenses the sheets S. The sheets S stored in the feeding unit 2 configured as described above are dispensed in accordance with a size specified by the control unit 310 ( FIG. 3 ) of the image forming apparatus A. The sheets S supplied from the multiple cassettes 2a, 2b, and 2c are further conveyed downstream by conveyance rollers 7. The leading edges of the sheets conveyed by the conveyance rollers 7 are aligned by a pair of registration rollers 8, and skew is corrected. The sheets S, whose leading edges have been aligned by the pair of registration rollers 8, are then fed to the downstream image forming unit 3 at a predetermined timing.

[0013] A large-capacity cassette 2d and a manual feed tray 2e are connected to the image forming apparatus A. The large-capacity cassette 2d is an optional unit that stores sheets of a size that are consumed in large quantities. The manual feed tray 2e is configured to be able to feed special sheets that are difficult to separate and feed, such as cardboard sheets, coated sheets, and film sheets.

[0014] The image forming unit 3 may be configured to form an image on the sheet S fed from the feeding unit 2, and various image forming mechanisms may be employed. In the illustrated embodiment, an electrostatic image forming mechanism is shown as the image forming unit 3. However, the image forming unit 3 is not limited to the illustrated electrostatic image forming mechanism, and an inkjet image forming mechanism, an offset image forming mechanism, or the like may also be employed.

[0015] The image forming unit 3 shown in FIG. 1 includes a drum- or belt-shaped photoconductor 9, an exposure device 10 that exposes the photoconductor 9, a development device 11 that develops the photoconductor 9 with toner, a charging device (not shown) that charges the photoconductor 9, and a cleaner (not shown) that cleans the photoconductor 9. FIG. 1 shows a monochrome printing mechanism as an example. The photoconductor 9 is exposed by the exposure device 10 to form an electrostatic latent image, which is then developed by the development device 11 to form a toner image on the photoconductor 9. The toner image formed on the photoconductor 9 is transferred by a transfer device 12 to a sheet S conveyed from a pair of registration rollers 8. The sheet S with the transferred toner image is fixed by a fixing device 13. The image forming apparatus A also includes a reversing conveyance path, where the sheet S with the fixed toner image is turned over by the fixing device 13 and then sent again to the pair of registration rollers 8, where an image is formed on the back side of the sheet S. Discharge rollers 15 are provided downstream of the fixing device 13 and downstream of the branch to the reverse conveying path, and the discharge rollers 15 transport the sheet S from a discharge outlet 16 of the image forming device A to a sheet processing device B described later.

[0016] An image reading unit A2 that optically reads an original image is provided above the image forming unit A1 configured in this manner, and an original feeding unit A3 is mounted above the image reading unit A2.

[0017] The image reading unit A2 includes a first platen glass 17, a second platen glass 21, a reading carriage 18 having a light source, a photoelectric conversion element 19, and a reduction optical system 20 formed by combining mirrors and lenses. The reading carriage 18 scans along the first platen glass 17, irradiating the image of an original document placed on the first platen glass 17 with light from the light source, and the reduction optical system 20 guides the reflected light from the image of the original document to the photoelectric conversion element 19, thereby reading the image. The photoelectric conversion element 19 converts image data into an electrical signal and transfers it to the image forming unit 3, so that the image read by the image reading unit A2 can be formed on a sheet by the image forming unit A1.

[0018] The document feeding unit A3 includes a feed tray 22 and a discharge tray 24, and transports documents placed on the feed tray 22 one by one, passes them over the second platen glass 21, and discharges them onto the discharge tray 24. When reading a document fed from the document feeding unit A3 and passing over the second platen glass 21, the reading carriage 18 is stopped below the second platen glass 21 in advance, and image data is read from the image passing over the second platen glass 21.

[0019] [Overall Configuration of Sheet Processing Apparatus] Next, the overall configuration of sheet processing apparatus B, which performs various processes such as binding and folding on sheets conveyed from image forming apparatus A, will be described with reference to Fig. 2. Fig. 2 shows the detailed configuration of sheet processing apparatus B. Sheet processing apparatus B processes sheets received from receiving section 26, which is the entrance of conveying path 28 connected to discharge outlet 16 of image forming apparatus A, and can then stack the sheets on a first tray (first stacking tray) 49, a saddle discharge unit 131, and a second tray (second stacking tray) 71, which will be described later. In this embodiment, the term "path" refers to the entire route along which sheets are conveyed by conveying guides, conveying rollers, etc.

[0020] In the illustrated device, a sheet sent to a conveying path 28 as a conveying path and a first conveying path is discharged to a first tray 49 after being processed by a processing section B1 described later, or a sheet conveyed on the conveying path 28 is discharged to a second tray 71, or a sheet is discharged to a saddle discharge unit 131 after being processed by a saddle section B2 described later. Each device has a control section, a communication section, etc., as shown in the block diagram illustrating the control configuration of the entire device in Figure 3, and controls the device using these sections.

[0021] Processing section B1, which serves as an end binding processing section, is disposed below the path exit (transfer section 35) of conveying path 28, and is capable of collating and stacking multiple sheets sequentially delivered from conveying path 28 via transfer section 35 to form a sheet bundle, and performing a binding process, which is an example of a predetermined process, on the end of this sheet bundle. The bound sheet bundle is stacked on first tray 49, which serves as a stacking section. The rear end (upstream end) of the sheet or sheet bundle stacked on first tray 49 abuts against stacking wall 50 on the upstream side of first tray 49 in the sheet discharge direction, and the sheet or sheet bundle is stacked along stacking wall 50.

[0022] The first tray 49 can be raised and lowered relative to the processing tray 37, which will be described later, and stacks a sheet bundle that has been bound by a binding processing mechanism 47, which will be described later. In this embodiment, the first tray 49 and the second tray 71 can be raised and lowered by a lifting mechanism (not shown). That is, in this embodiment, when sheets are sent to the first tray 49 or the second tray 71 serving as a stacking tray, the first tray 49 or the second tray 71 is raised and lowered to keep the position of the top sheet on the stacking surface of the tray constant relative to the discharge roller pair 42 or the second discharge roller 207 so that the alignment of the stacked sheets does not deteriorate.

[0023] The saddle section B2 is disposed below the receiving / transferring section of the saddle path 32, which serves as a second conveying path branching vertically downward from the conveying path 28, and collates and accumulates a plurality of sheets sequentially delivered from the conveying path 28 via the saddle path 32 and the receiving / transferring section to form a sheet bundle, and then saddle-stitches the sheets or folds them without saddle-stitching them, and discharges them to the saddle discharge unit 131. Each component will be described in detail below.

[0024] [Housing] As shown in FIG. 2 , the sheet processing apparatus B includes a housing 27, a transport path 28, a processing section B1, a saddle section B2, a first tray 49, a saddle discharge unit 131, a second tray 71, and the like. The transport path 28, processing section B1, and saddle section B2 are disposed inside the housing 27. The transport path 28 also includes a sheet receiving section 26 and a sheet delivery section 35. The processing section B1 and saddle section B2 process sheets delivered from the delivery section 35 of the transport path 28. The first tray 49, the saddle discharge unit 131, and the second tray 71 stack sheets sent from each processing section. The illustrated housing 27 is connected to the housing 1 of the image forming apparatus A, which is located upstream of the transport path 28 in the sheet transport direction. The housing 27 and the housing 1 are arranged so that the heights of the discharge port 16 of the image forming apparatus A and the receiving section 26 of the sheet processing apparatus B from the installation surface are approximately the same, and the discharge port 16 and the receiving section 26 are connected. In this embodiment, the housing includes an exterior cover and a support frame.

[0025] [Sheet Loading Path] The transport path 28, which is the sheet loading path, is a substantially linear path that crosses the housing 27 in a substantially horizontal direction and includes a receiving section 26 that is connected to the discharge outlet (main body discharge outlet) 16 of the image forming apparatus A, and a delivery section 35 that is located on the opposite side of the apparatus from the receiving section 26. The transport path 28 is provided with an entrance roller 29, a first transport roller 201, a second transport roller 202, and a third transport roller 203 that are transport rollers that can transport a sheet in a first direction from the receiving section 26 toward the first discharge path 31 and can transport a sheet in a second direction from the first discharge path 31 toward the receiving section 26. That is, the entrance roller 29, the first transport roller 201, the second transport roller 202, and the third transport roller 203 can transport a sheet in the transport path in the first direction and in a second direction opposite to the first direction, and are arranged in this order from the receiving section 26 side.

[0026] The first discharge path 31 is connected to a transfer section 35 of the conveying path 28, and a first conveying roller 36 is disposed at this connection section. A sheet that is transferred from the conveying path 28 to the first discharge path 31 and then discharged from the first discharge path 31 is stacked on a first tray 49 or guided to processing section B1. Note that each of the above-mentioned conveying rollers may be other members capable of conveying a sheet, such as a conveying belt.

[0027] 2, the conveying path 28 is connected to a saddle path 32 and an upper conveying path 30, which are branch paths. The saddle path 32 and the upper conveying path 30 are arranged in this order in the first direction from the receiving unit 26 toward the first discharge path 31. The saddle path 32 branches off from the conveying path 28 in the vertically downward direction, and the upper conveying path 30 branches off from the conveying path 28 in the vertically upward direction. At the branch points of the conveying path 28, and the saddle path 32 and the upper conveying path 30, respectively, a saddle path switching member 33 and an upper conveying path switching member 34 are arranged as switching members that switch the conveying direction of the conveyed sheet.

[0028] [Path branching means] The upper conveying path switching member 34 is composed of a switching guide that moves to change the conveying path so that the sheet transported from the receiving section 26 is transported to either the first discharge path 31 or the upper conveying path 30, and is moved by a drive unit (not shown) such as an electromagnetic solenoid or a mini motor.

[0029] [Upper Conveyance Path] The upper conveyance path 30 (printout discharge path), which conveys sheets other than those discharged to the first discharge path 31, branches off from the conveyance path 28, and the path branch is provided with an upper conveyance path switching member 34 for guiding the sheet to the upper conveyance path 30. The upper conveyance path 30 is also provided with a fourth conveyance roller 204, a fifth conveyance roller 205, a sixth conveyance roller 206, and a second discharge roller 207 as conveyance rollers that guide the sheet to the second tray 71. As a result, the sheet guided to the upper conveyance path 30 is discharged from the upper conveyance path discharge port 40 to the second tray 71 (overflow tray).

[0030] The processing section B1 is composed of a processing tray 37 as a loading section for loading sheets transported through the first discharge path 31 downstream of the transport path 28 and collating and stacking the loaded sheets, and a binding mechanism 47 for binding the stacked sheet bundle. The processing section B1 performs binding on the sheet bundle loaded on the processing tray 37. The binding mechanism 47 is disposed vertically below the transport path 28. As shown in FIG. 2 , the first discharge path 31 has a step formed therebelow, and the processing tray 37 is disposed below the step. A first switchback path is provided between the first discharge path 31 and the processing tray 37. The first switchback path reverses the transport direction of a sheet after it has been partially discharged from the discharge opening 31 a of the first discharge path 31 to the first tray 49, and guides the sheet onto the processing tray 37.

[0031] Specifically, the first discharge path 31 is provided with upper conveying rollers 41 and lower conveying rollers 48 that sandwich and convey a sheet. The upper conveying rollers 41 and the lower conveying rollers 48 form a pair of discharge rollers 42 as a discharge section. The upper conveying roller 41 can come into contact with and separate from the lower conveying roller 48, and can convey the sheet in a direction toward the first tray 49 with the upper conveying roller 41 and the lower conveying roller 48 sandwiching the sheet, and in a direction opposite to this direction. The upper conveying rollers 41 and the lower conveying rollers 48 can then convey the sheet toward the processing tray 37 via the first switchback path.

[0032] Furthermore, the upper conveying roller 41 and the lower conveying roller 48 (i.e., the discharge roller pair 42) discharge the sheet or sheet stack on the processing tray 37 from the discharge opening 31a to a first tray 49 serving as a stacking tray (stacking portion). The discharge opening 31a is an opening above the lower conveying roller 48 of the housing 27. Furthermore, the discharge roller pair 42 discharges the sheet that has been conveyed to the first discharge path 31 without passing through the processing tray 37 from the discharge opening 31a to the first tray 49.

[0033] The binding mechanism 47 has a trailing edge regulating section 47a that contacts the edge (trailing edge) of a sheet to position the sheet. A raking section 38 is disposed on the processing tray 37, which transports the sheet, transported to the processing tray 37 by the upper transport rollers 41 and the lower transport rollers 48, toward the trailing edge regulating section 47a. The binding mechanism 47 binds the edge of a sheet bundle made up of multiple sheets that is placed on the processing tray 37 and whose edge positions are regulated by the trailing edge regulating section 47a. The binding mechanism 47 also has a sheet bundle discharge mechanism that discharges the sheet bundle to the first tray 49 after stapling the edge of the sheet bundle.

[0034] 2 supports the sheets fed from the first discharge path 31 so as to straddle the processing tray 37 and the first tray 49 on the downstream side thereof. In other words, the leading edge of the sheet fed from the first discharge path 31 is supported on the uppermost sheet of the first tray 49 on the downstream side, and the trailing edge is supported on the processing tray 37.

[0035] [Saddle Path] A saddle path 32 for conveying a sheet to the saddle section B2 is connected to the conveying path 28, and a path branch section is provided with a saddle path switching member 33 for guiding a sheet to the saddle path 32. The sheet guided to the saddle section B2 by the saddle path 32 is center-folded and folded, and then discharged to the saddle discharge unit 131 via a post-fold path guide 114, a second roller post-path guide 116, a clamp pre-guide 119, and a saddle discharge guide 124. In this embodiment, the saddle discharge guide 124 as a discharge guide section is used as an auxiliary guide to ensure that the sheet is properly stacked in the saddle discharge unit 131.

[0036] [Control Configuration] An outline of the control configuration of image forming system 1000 will be described using Figure 3. First, image forming apparatus A has a control unit 310, an operation unit 302, a conveyance control unit 303, an image processing unit 304, a drive unit 305, and a communication unit 306. The control unit 310 has a CPU (Central Processing Unit) 311, a ROM (Read Only Memory) 312, and a RAM (Random Access Memory) 313. The CPU 311 controls each unit while reading out programs corresponding to control procedures stored in the ROM 312. In addition, working data and input data are stored in the RAM 313, and the CPU 311 performs control by referring to the data stored in the RAM 313 based on the programs and the like.

[0037] The operation unit 302 is, for example, an operation panel provided in the image forming apparatus A and connected to the control unit 310, through which an operator operates the apparatus and performs various settings. The transport control unit 303 controls various transport rollers that transport sheets in the image forming apparatus A and a switching member that switches the transport path. The image processing unit 304 controls the image forming unit 3. The drive unit 305 controls various motors and power supplies. The communication unit 306 connects the control unit 310 to an external device 301 such as a personal computer and a communication unit 321 of the sheet processing apparatus B so that the control unit 310 can communicate with each other.

[0038] The sheet processing apparatus B includes a stacker control unit 330, a conveyance control unit 322, an edge binding control unit 323, a discharge processing control unit 324, and a communication unit 321. The stacker control unit 330, like the control unit 310, includes a CPU 331, a ROM 332, and a RAM 333. The conveyance control unit 322 controls various conveyance rollers that convey sheets and switching members that switch conveyance paths in areas other than the saddle unit B2 of the sheet processing apparatus B. The edge binding control unit 323 controls the processing unit B1. The discharge processing control unit 324 controls sheet discharge and various stacking trays on which the discharged sheets are stacked. The communication unit 321 communicatively connects the stacker control unit 330 to the communication unit 306 of the image forming apparatus A and the communication unit 341 of the saddle unit B2. Communication between the communication unit 306 and the communication unit 321 may be performed via wired or wireless communication.

[0039] The saddle unit B2 includes a saddle control unit 350, a conveyance control unit 342, a saddle stitching control unit 343, a center folding control unit 344, a square spine processing control unit 345, and a communication unit 341. Like the control unit 310, the saddle control unit 350 includes a CPU 351, a ROM 352, and a RAM 353. The conveyance control unit 342 controls various conveyance rollers that convey sheets in the saddle unit B2 and a switching member that switches the conveyance path. The saddle stitching control unit 343 controls the saddle stitching processing unit 104. The center folding control unit 344 controls the center folding processing mechanism C1. The square spine processing control unit 345 controls the square spine processing unit C2. The communication unit 341 communicatively connects the communication unit 321 of the sheet processing device B and the saddle control unit 350. In this embodiment, the saddle control unit 350 communicates with the stacker control unit 330 via the communication units 341 and 321. However, a common control unit may control each unit. In this embodiment, the sheet processing apparatus B is controlled by a conveyance control unit 322, an edge binding control unit 323, a discharge processing control unit 324, a stacker control unit 330, and a saddle control unit 350. However, each unit may be controlled by a single control unit. In this embodiment, the saddle control unit 350 is an example of a control unit. However, when control is performed using a control unit common to other control units as described above, the common control unit is an example of a control unit.

[0040] [Saddle Section] The saddle section B2 will be described with reference to FIGS. 2 and 4. The saddle section B2 includes a center-folding mechanism C1 and a square spine processing section C2. The center-folding mechanism C1 collates and stacks sheets fed from the conveying path 28 to form a sheet bundle, binds the sheet bundle at the center of the sheet bundle (the middle of the second conveying direction, which is the conveying direction of the saddle path rollers 100, described later), and performs a center-folding process to fold the sheet bundle at the stitched position. The square spine processing section C2 is located downstream of the center-folding mechanism C1 in the sheet bundle conveying direction (the downstream of the first conveying direction, which is the conveying direction of the third saddle roller pair 118, described later). The square spine processing section C2 forms a square spine on the center-folded sheet bundle. In this embodiment, for convenience, the fold portion of the center-folded sheet bundle before the square spine processing is also referred to as the spine of the sheet bundle. A saddle discharge unit 131 is disposed downstream in the first conveyance direction of the square spine processing unit C2, and stacks the bound sheet bundle. It is also possible to align and stack one or more sheets, and then perform saddle stitching and center folding, which folds the center of the conveyance direction, without square spine processing.

[0041] [Center Folding Mechanism] The center folding mechanism C1 includes a leading edge restriction stopper 109, a saddle stitching processing section (saddle stitch stapling unit) 104 as a saddle stitching processing unit, and a center folding processing section 112 as a center folding processing unit. The center folding processing mechanism C1 accumulates sheets into a stack and performs center folding and saddle stitching. Specifically, sheets transported from the transport path 28 to the saddle path 32 are transported by saddle path rollers 100 to a saddle stack tray 150, which serves as a stacking section and a second stacking section. The saddle stack tray 150 accumulates multiple sheets transported in the second transport direction by the saddle path rollers 100 via the saddle path 32 to form a sheet stack. The sheet stack accumulated on the saddle stack tray 150 is positioned at a predetermined position on the saddle stack tray 150 by the leading edge restriction stopper 109. The saddle stitching processing section 104 performs binding on the center portion of the sheet stack positioned by the leading edge restriction stopper 109 in the transport direction (middle portion in the second transport direction). The center folding processing section 112 has a push plate 112a and a pair of folding rollers 113, and folds the sheet bundle by pushing the push plate 112a near the position where the binding processing was performed by the center binding processing section 104 (the center of the sheet bundle in the conveying direction of the binding processing) while transporting the sheet bundle with the pair of folding rollers 113, so that the spine of the sheet bundle is transported downstream in the conveying direction.

[0042] The saddle stitching unit 104 is a mechanism that performs binding by moving the sheet stack between a head unit and an anvil unit along the center line of the sheets while sandwiching the sheet stack. The center folding unit 112, as shown in Figures 2 and 4, uses a pusher plate 112a to insert the sheet stack into the nip between a pair of folding rollers 113 that are pressed against each other, and then conveys the sheet stack while folding it by the rotation of the pair of folding rollers 113.

[0043] [Square Spine Processing Unit] The square spine processing unit C2, which serves as a square spine processing unit, processes a sheet bundle to square the spine along the crease (line) of the center-folded sheet bundle. The square spine processing unit C2 includes a pair of clamping units, a lower clamping unit 120 and an upper clamping unit 121, and a square spine processing unit 134 having a pressure roller 123. The lower clamping unit 120 and the upper clamping unit 121 clamp and release the sheet bundle by moving relatively along the thickness direction of the sheet bundle conveyed by the saddle third roller pair 118 (described later). The lower clamping unit 120 and the upper clamping unit 121 are an example of a clamping unit that clamps the saddle-stitched and center-folded sheet bundle. The pressure roller 123 is an example of a pressing unit that presses the spine of the sheet bundle toward the lower clamping unit 120 and the upper clamping unit 121.

[0044] The pressure roller 123 presses the spine of the sheet bundle by moving along the width direction of the sheet bundle (a direction perpendicular to the conveyance direction of the sheet bundle, the direction of the rotation axis of the third saddle roller pair 118, the front-to-back direction in FIGS. 2 and 4 ). The square spine processing unit C2 performs square spine processing by pressing the spine of the sheet bundle clamped between the lower clamp unit 120 and the upper clamp unit 121 with the pressure roller 123 while the spine of the sheet bundle protrudes downstream relative to the lower clamp unit 120 and the upper clamp unit 121 in the first conveyance direction. The "corner" mentioned above includes a curved surface, and refers to the boundary between the front cover and the spine, and the boundary between the spine and the back cover of the sheet bundle. In this embodiment, the "orthogonal direction" does not only refer to the orthogonal direction, but also includes a direction that is approximately orthogonal and a direction that intersects. In other words, it also includes cases where the conveyance direction of the sheet bundle and the width direction of the sheet bundle are not necessarily orthogonal. The term "orthogonal directions" also includes intersecting directions in the following description.

[0045] Specifically, the square spine processing unit C2 clamps a portion of the sheet bundle from both sides in the vertical direction (thickness direction of the sheet bundle) while the spine of the sheet bundle center-folded by the center-folding processing mechanism C1 protrudes downstream in the first conveyance direction. The pressure roller 123 presses the spine of the sheet bundle clamped between the lower clamp unit 120 and the upper clamp unit 121 toward the lower clamp unit 120 and the upper clamp unit 121 in the width direction of the sheet bundle, which is perpendicular to the conveyance direction and thickness direction of the sheet bundle. In this way, the square spine processing unit C2 performs square spine processing to form a corner on the spine of the sheet bundle. The square spine processing is a process in which the pressure roller 123 flattens the spine of the sheet bundle shown in Figures 16A and 16B (described later), forming two creases in the spine of the sheet bundle and forming two corners on the spine of the sheet bundle, as shown in Figures 16C and 16D. The two corners of the spine of the sheet bundle are formed at positions in the thickness direction of the sheet bundle that will sandwich the staples driven in when the sheet bundle is bound by the saddle stitching processing unit 104. The two corners of the spine of the sheet bundle are also formed at positions that will sandwich the folds that are formed when the center folding processing unit 112 performs the center folding.

[0046] In addition, a center-folding conveying mechanism is arranged between the center-folding processing mechanism C1 and the square spine processing section C2, which conveys the sheet stack center-folded by the center-folding processing mechanism C1 to the downstream square spine processing section C2 and stops it.

[0047] As described above, the processing section B1 and the conveying path 28 are disposed in a substantially horizontal direction, the saddle path 32 that guides the sheets to the saddle section B2 is disposed in a substantially vertical direction, and the saddle stack tray 150 that collates and stacks the sheets is disposed so as to follow the substantially vertical direction. By disposing the conveying path 28 in a direction that crosses the housing 27 in this way, and disposing the saddle path 32 and the saddle section B2 in a substantially vertical direction, it is possible to reduce the width (size) of the device in the horizontal direction.

[0048] A saddle discharge unit 131 is disposed downstream of the saddle portion B2 in the sheet bundle conveying direction, and stores the sheet bundle processed by the saddle portion B2. The illustrated saddle discharge unit 131 is disposed vertically below the first tray 49.

[0049] [Configuration of Saddle Section] Next, the configurations of the center-folding processing mechanism C1, center-folding conveyance mechanism C3, and square spine processing section C2 that constitute the saddle section B2 will be described in more detail.

[0050] 2, the saddle path switching member 33 is switched so as to transport the sheet to the saddle path 32, thereby guiding the sheet to the center-folding processing mechanism C1. In the height direction of the center-folding processing mechanism C1, there are arranged, in order from the upper vertical side (upstream side) that is the entrance side, a saddle entrance roller 101, a sorting beater 102, a trailing edge press guide 103, a saddle stitching processing section 104, a pull-in separation roller 105, a center-folding processing section 112, a first alignment roller 107, a second alignment roller 108, a leading edge regulating stopper 109, and a leading edge gripper 110.

[0051] The saddle inlet rollers 101 further convey the sheets delivered by the saddle path rollers 100 from the saddle path 32 downward. An inlet sensor 190 is provided upstream of the saddle inlet rollers 101 to detect when the sheet reaches the saddle path 32. The sorting beater 102 shifts the sheets conveyed downward from the saddle inlet rollers 101 to the right side in FIG. 2 and accumulates the sheets on the saddle stack tray 150. The trailing edge press guide 103 presses the trailing edges of the sheets stacked on the saddle stack tray 150. The saddle stitching processing unit 104 performs a stitching process on the center of the sheet stack accumulated on the saddle stack tray 150 in the conveying direction. The pull-in separation rollers 105 assist in the conveyance of the sheets conveyed to the saddle stack tray 150 and pull the sheets toward the leading edge regulating stopper 109. The pull-in and separation roller 105 is disposed so as to be able to come into contact with and separate from the opposing roller 105a.

[0052] The center-folding processing section 112 has a pair of folding rollers 113, a pushing plate 112a as a pressing section, and a roller guide 111. The pair of folding rollers 113 form creases during center-folding. The pushing plate 112a pushes the sheet into the nip between the pair of folding rollers 113. The roller guide 111 covers the pair of folding rollers 113. The first alignment roller 107 and the second alignment roller 108 transport the sheet transported to the saddle stack tray 150 and align the sheet in the height direction. The leading edge regulating stopper 109 abuts against the leading edge (lower edge) of the transported sheet, thereby determining the height position of the leading edge of the sheet. The leading edge gripper 110 presses the leading edge (lower edge) of the sheet stacked on the leading edge regulating stopper 109.

[0053] The saddle inlet roller 101 and the lead-in separation roller 105 are driven by the same motor. The trailing edge presser guide 103 is positioned opposite the sorting beater 102, sandwiching the saddle stack tray 150 therebetween. The saddle stitching processing section 104 is disposed downstream of the sorting beater 102 and the trailing edge presser guide 103, and upstream of the lead-in separation roller 105.

[0054] A sheet conveyed from the saddle path 32 to the saddle section B2 is conveyed by the saddle inlet rollers 101 to a leading edge regulating stopper 109 that has moved to a position according to the sheet size. The pull-in separation rollers 105 have an auxiliary conveyance function for accurately conveying the sheet being conveyed to the leading edge regulating stopper 109 in the saddle stack tray 150. At this time, the pair of folding rollers 113 are covered by roller guides 111 to prevent the leading edge of the sheet from getting caught on the pair of folding rollers 113 and to convey the sheet efficiently.

[0055] The first alignment roller 107 and the second alignment roller 108 accurately abut the conveyed sheet against a leading edge regulation stopper 109, and align the sheet in the height direction.

[0056] The sorting beater 102 prepares to receive the next sheet by bringing the sheet that has been conveyed to the leading edge regulating stopper 109 up to the trailing edge press guide 103 and holding down the trailing edge (upper edge) of the brought-up sheet with the trailing edge press guide 103. At this time, the trailing edge press guide 103 moves to a position according to the size and waits there.

[0057] The leading edge (lower edge) of the sheet bundle formed by stacking a predetermined number of sheets on the saddle stack tray 150 is gripped and fixed by the leading edge gripper 110. In this state, the saddle stitching processing unit 104 performs a binding process on the center of the sheet bundle in the second conveyance direction. After the binding process, the leading edge regulating stopper 109 is lowered while the leading edge (lower edge) of the sheet bundle is still gripped by the leading edge gripper 110. At this time, the leading edge regulating stopper 109 is lowered so that the position where the abutting plate 112a pushes the pair of folding rollers 113 is half the sheet size, thereby lowering the sheet bundle from the binding position.

[0058] When performing center folding, the roller guide 111 is retracted, the leading edge gripper 110 is released, and then the abutting plate 112a pushes the center of the sheet stack into the nip portion of the pair of folding rollers 113. This causes the sheet stack to be center folded.

[0059] The saddle inlet roller 101, the pull-in separation roller 105, the sorting beater 102, and the trailing edge press guide 103 are controlled by a conveyance control unit 342 (FIG. 3). In addition, the leading edge regulating stopper 109, the leading edge gripper 110, the saddle stitching processing unit 104, the first alignment roller 107, and the second alignment roller 108 are controlled by a saddle stitching control unit 343 (FIG. 3). In addition, the folding roller pair 113 and the abutting plate 112a are controlled by a center folding control unit 344 (FIG. 3).

[0060] [Center-Folding Conveying Mechanism] The configuration of the center-folding conveying mechanism C3 will be described with reference to FIGS. 2 and 4. The center-folding conveying mechanism C3 transfers the sheet bundle center-folded by the center-folding mechanism C1 to the square spine processing unit C2. Specifically, the center-folding conveying mechanism C3 first conveys the center-folded sheet bundle directly using the folding roller pair 113 so that the spine of the sheet bundle is located downstream in the conveying direction from the edge of the fore-edge, and then transfers the sheet bundle to the post-folding path guide 114. The post-folding path guide 114 is disposed downstream in the conveying direction from the folding roller pair 113 along a direction (here, substantially horizontal) that bends downward in the vertical direction with respect to the folding roller conveying direction 113c (FIG. 2), which is a direction along a perpendicular line (first virtual line α2, FIG. 4, described below) to a line passing through the rotation centers of the folding roller pair 113, which serves as the first conveying roller pair.

[0061] As shown in FIG. 4 , a first line α1 passing through the rotation centers of the pair of folding rollers 113 and a line perpendicular to the width direction (the direction perpendicular to the conveying direction of the sheet stack, i.e., the front-to-back direction in FIGS. 2 and 4 ) and passing through the nip of the pair of folding rollers 113 when the sheet stack is not being sandwiched are defined as a first imaginary line α2. In this case, the pair of folding rollers 113 are disposed so that the first imaginary line α2 is parallel to the horizontal direction or tilts upward in the vertical direction relative to the horizontal direction as it moves downstream in the conveying direction. In this embodiment, the first imaginary line α2 tilts upward in the vertical direction relative to the horizontal direction as it moves downstream in the conveying direction. Meanwhile, the post-fold path guide 114 extends in a direction tilted relative to the first imaginary line α2, and in this embodiment, it extends in a substantially horizontal direction.

[0062] The post-fold path guide 114 guides the sheet bundle conveyed by the folding roller pair 113 and leads the sheet bundle to a saddle second roller pair 115 located downstream in the conveying direction. The post-fold path guide 114 also has a second post-fold path lower guide 114a that guides the vertical lower side of the conveyed sheet bundle, and a second post-fold path upper guide 114b that guides the upper side of the sheet bundle. A saddle second roller conveying direction 115c, which is a direction along a perpendicular to a line passing through the rotation centers of each roller of the saddle second roller pair 115, is disposed along a direction that descends vertically downward as it moves downstream in the conveying direction. The saddle second roller pair 115 is driven by the center folding control unit 344 to convey the sheet bundle.

[0063] The sheet bundle conveyed by the saddle second roller pair 115 is delivered to and guided by a second roller post-path guide 116 disposed downstream in the conveying direction and parallel to a saddle second roller conveying direction 115c (FIG. 2). The second roller post-path guide 116 also has a second roller post-path lower guide 116a that guides the lower side of the conveyed sheet bundle in the vertical direction, and a second roller post-path upper guide 116b that guides the upper side of the sheet bundle.

[0064] The second roller post-path guide 116 guides the sheet bundle conveyed by the saddle second roller pair 115 to the saddle third roller pair 118 located downstream in the conveying direction. The saddle third roller conveying direction 118c (FIG. 2), which is a direction perpendicular to a line passing through the rotation centers of the rollers of the saddle third roller pair 118 (the second virtual line β2 described below, FIG. 4), is arranged in a direction that descends vertically downward as it moves downstream in the conveying direction. A saddle conveying sensor 117 is located downstream in the conveying direction from the saddle third roller pair 118 and between the sheet bundle receiving port and the sheet bundle discharge port. This saddle conveying sensor 117 detects the presence or absence of a sheet bundle. Therefore, by detecting the presence or absence of a sheet bundle, it is possible to detect that the leading edge of the sheet bundle has reached the saddle conveying sensor 117.

[0065] The saddle third roller pair 118, which serves as a conveying means and a conveying roller pair, is driven by the center folding control unit 344 to sandwich and convey the sheet bundle that has been saddle-stitched and center-folded so that the spine of the sheet bundle is located downstream of the edge of the fore-edge in the conveying direction. In other words, the saddle third roller pair 118 conveys the sheet bundle so that the spine of the sheet bundle leads. Hereinafter, the upstream side and downstream side of the first conveying direction (saddle third roller conveying direction 118c), which is the direction in which the sheet bundle is conveyed by the saddle third roller pair 118, may also be simply referred to as the "upstream side" and the "downstream side."

[0066] The folding roller pair 113, the second saddle roller pair 115, and the third saddle roller pair 118 are each driven by a different motor, and the center folding control unit 344 controls the driving of each roller pair by controlling these motors. The third saddle roller pair 118 is a conveying roller pair located immediately upstream of the square spine processing unit C2, and sandwiches the sheet bundle center-folded by the center folding unit 112 and conveys it toward the square spine processing unit C2.

[0067] 4, a second line β1 passing through the rotation centers of the saddle third roller pair 118 and a line perpendicular to the width direction passing through the nip of the saddle third roller pair 118 when the sheet stack is not being sandwiched are defined as a second imaginary line β2. In this case, the saddle third roller pair 118 is disposed so that the second imaginary line β2 intersects with the first imaginary line α2 and is inclined downward in the vertical direction as it moves downstream in the conveying direction of the folding roller pair 113.

[0068] In other words, the saddle third roller pair 118 is disposed so that the second imaginary line β2 is inclined downward in the vertical direction relative to the horizontal direction as it moves downstream in the conveying direction. That is, in this embodiment, the second imaginary line β2 is inclined with respect to the first imaginary line α2. The folding roller pair 113 conveys the sheet bundle in a direction (folding roller conveying direction 113c) that is inclined upward in the vertical direction relative to the horizontal direction or the horizontal direction as it moves downstream in the conveying direction. In contrast, the saddle third roller pair 118 conveys the sheet bundle in a direction (saddle third roller conveying direction 118c) that is inclined downward in the vertical direction relative to the horizontal direction as it moves downstream in the conveying direction.

[0069] Therefore, in the present embodiment, the center-folding conveying path C4, which serves as a third conveying path for conveying the sheet bundle between the folding roller pair 113 and the saddle third roller pair 118, is bent so that the sheet bundle conveyed by the folding roller pair 113 is handed over to the saddle third roller pair 118. That is, the center-folding conveying path C4 has a post-folding path guide 114 and a post-second roller path guide 116, and the conveying path is bent between the post-folding path guide 114 and the post-second roller path guide 116. In other words, the direction in which the sheet bundle is guided by the post-folding path guide 114 is inclined relative to the direction in which the sheet bundle is guided by the post-folding path guide 114.

[0070] In this way, by differentiating the sheet bundle conveyance direction of the folding roller pair 113 from that of the saddle third roller pair 118 and bending the conveyance path between the post-fold path guide 114 and the post-second roller path guide 116, the width of the sheet processing apparatus B (length in the second conveyance direction, length in the left-right direction in FIG. 2 ) can be reduced, resulting in a more compact apparatus. Furthermore, by discharging the sheet bundle downward by the saddle third roller pair 118, with the folding roller conveyance direction 113c, which is the sheet conveyance direction of the saddle third roller pair 118, diagonally downward, the sheet bundle processed by the saddle section B2 can be discharged to a lower position in the apparatus. As a result, the saddle discharge unit 131, to which the sheet bundle processed by the saddle section B2 is discharged, can be located lower in the apparatus, increasing the distance that the first tray 49, located above the saddle discharge unit 131, can descend. As a result, the sheet stacking capacity of the first tray 49 can be increased. In addition, when the arrangement of the transport path guide for the above-mentioned sheet or sheet stack, or the transport direction of the sheet or sheet stack, is horizontal, vertical, or parallel, this also includes cases where there is an angle relative to the horizontal, vertical, or parallel due to tolerances, etc.

[0071] [Details of the Square Spine Processing Section] The square spine processing section C2 will be described with reference to Figures 2 and 4, as well as Figures 5 to 10. As described above, the square spine processing section C2 includes a pair of clamps, namely, a lower clamp unit 120 and an upper clamp unit 121, and a square spine processing unit 134 having a pressure roller 123. The clamp mechanism C5, which includes the lower clamp unit 120 and the upper clamp unit 121, includes a clamp front guide 119. The clamp front guide 119 is disposed downstream of the saddle third roller pair 118 in the conveying direction and along a direction that bends downward in the vertical direction relative to the saddle third roller conveying direction 118c, and guides the conveyance of the sheet stack.

[0072] The clamp front guide 119 includes a clamp front lower guide portion 119a that guides the bottom surface of the sheet stack and a clamp front upper guide portion 119b that guides the top surface of the sheet stack. The clamp front lower guide portion 119a and the clamp front upper guide portion 119b are positioned in the thickness direction away from a line centered on the saddle third roller conveyance direction 118c by more than half the thickness of the sheet stack that can pass through the device (the thickness of the sheet stack when a center-folding process is performed on a sheet stack with the maximum thickness that can be conveyed in the device). In other words, the distance between the clamp front lower guide portion 119a and the clamp front upper guide portion 119b is greater than the maximum thickness of the sheet stack that can be processed by the sheet processing device B (the maximum thickness of the sheet stack that can be center-folded by the center-folding mechanism C1). Here, the clamp front lower guide portion 119a is an example of a guide portion that guides the bottom surface of the sheet stack in the vertical direction.

[0073] The lower clamp unit 120 and the upper clamp unit 121 are relatively movable between a first position where they can receive the sheet bundle conveyed from the saddle third roller pair 118 and a second position where they clamp the sheet bundle. By moving from the first position to the second position, the lower clamp unit 120 and the upper clamp unit 121 clamp a portion of the sheet bundle from both sides in the thickness direction of the sheet bundle.

[0074] In this embodiment, the upper clamp unit 121 is movable, and the lower clamp unit 120 is fixed. That is, the upper clamp unit 121 is configured to clamp the sheet bundle by moving in a direction approaching the lower clamp unit 120. Therefore, in this embodiment, the lower clamp unit 120 corresponds to a fixed first clamp, and the upper clamp unit 121 is movable in a direction approaching the lower clamp unit 120 and a direction away from the lower clamp unit 120, and corresponds to a second clamp that clamps the sheet bundle together with the lower clamp unit 120. However, the upper clamp unit 121 may be fixed and the lower clamp unit 120 may be movable, or both may be movable. In either case, the sheet stack is clamped between an upper clamp surface (upper clamp pressing portion) 142, which is the surface of the upper clamp unit 121 facing the lower clamp unit 120, and a lower clamp surface (lower clamp pressing portion) 143, which is the surface of the lower clamp unit 120 facing the upper clamp unit 121 (see Figures 16A to 16D).

[0075] The lower clamp surface 143 of the lower clamp unit 120 and the upper clamp surface 142 of the upper clamp unit 121 are parallel to the clamp front lower guide portion 119a and the clamp front upper guide portion 119b, respectively, and are disposed downstream of the clamp front guide 119 in the sheet bundle conveying direction. The sheet bundle conveyed while being guided by the clamp front guide 119 is further guided by the upper clamp surface 142 and the lower clamp surface 143 to be conveyed a predetermined amount. The clamp front upper guide portion 119b is fixed to the lower clamp unit 120, and the clamp front lower guide portion 119a is fixed to the upper clamp unit 121. In this embodiment, the clamp front lower guide portion 119a moves together with the upper clamp unit 121 in a substantially vertical direction (the thickness direction of the sheet bundle).

[0076] [Square spine processing unit] Next, the internal configuration of the square spine processing unit 134 will be described using Figures 5 to 10. The square spine processing unit 134 has a unit frame 147, roller pressure units 138a, 138b, pressure springs 145a, 145b, an upper movement restriction unit 139, and a lower movement restriction unit 140 as components for supporting and moving the pressure roller (square spine processing roller) 123. As shown in Figure 10, the pressure roller 123 is arranged so that its outer circumferential surface contacts the downstream end surfaces of the lower clamp unit 120 and the upper clamp unit 121. In addition, as shown in Figure 6B, a roller shaft 141 is arranged on the inner diameter side of the pressure roller 123, and the pressure roller 123 is rotatable relative to the roller shaft 141.

[0077] 6A and 6B, the unit frame 147 has a pair of side plates 147a arranged on either side of the pressure roller 123, a rear plate 147b arranged on the left side of the pressure roller 123 on the downstream side (FIG. 6B) in the first conveying direction, and an upper plate 147c and a lower plate 147d arranged on either side in the rotational axis direction of the pressure roller 123 and provided so as to bend from both ends of the rear plate 147b. By configuring the unit frame 147 in this way, the pressure roller 123 is housed inside the side plates and the pressure roller 123 is exposed on the upstream side in the first conveying direction.

[0078] In this embodiment, the rear side plate 147b, upper side plate 147c, and lower side plate 147d are integrally formed, and as shown in FIG. 6B, they have a generally U-shaped cross section. These may be separate bodies, or may be integrally formed with the pair of side plates 147a. Both ends of the roller shaft 141 of the pressure roller 123 are rotatably supported by the upper side plate 147c and the lower side plate 147d, respectively. The upper side plate 147c and the lower side plate 147d extend upstream of the pressure roller 123 in the first conveying direction, and an upper movement restricting portion 139 and a lower movement restricting portion 140 are supported at their leading end portions, respectively.

[0079] That is, the upper movement restricting portion 139 is provided at the tip of a support shaft 139a fixed to the upper plate 147c and extending downward from the upper plate 147c. The lower movement restricting portion 140 is provided at the tip of a support shaft 140a fixed to the upper plate 147c and extending downward from the lower plate 147d. The upper movement restricting portion 139 is a roller rotatably supported at the tip of the support shaft 139a, and the lower movement restricting portion 140 is a roller rotatably supported at the tip of the support shaft 140a. In this embodiment, two lower movement restricting portions 140 are arranged side by side, but one may be provided. The number of upper movement restricting portions 139 may also be two. The upper movement restricting portion 139 and the lower movement restricting portion 140 are located on both sides of the pressure roller 123 in the direction of the rotational axis of the roller shaft 141.

[0080] Roller pressure members 138a and 138b are connected to the roller shaft 141 on the outer side of the pressure roller 123 in the roller thickness direction and downstream in the conveying direction. Pressure springs 145a and 145b are arranged between the roller pressure members 138a and 138b and a rear side plate 147b of the unit frame 147, and the pressure springs 145a and 145b urge the roller shaft 141. Because the roller shaft 141 is configured to be movable in the conveying direction, the pressure with which the pressure roller 123 presses the spine of the sheet stack due to the urging forces of the pressure springs 145a and 145b changes in accordance with changes in the amount of protrusion of the spine of the sheet stack from the lower clamp unit 120 and the upper clamp unit 121, which will be described later.

[0081] Furthermore, the pressure roller 123 is biased by pressure springs 145a and 145b via the roller shaft 141, and is therefore pressed against the lower clamp unit 120 and the upper clamp unit 121. On the other hand, an upper movement restricting portion 139 and a lower movement restricting portion 140 are arranged on the opposite side of the pressure roller 123 with the lower clamp unit 120 and the upper clamp unit 121 sandwiched therebetween, so as to face the lower clamp unit 120 and the upper clamp unit 121, respectively (FIG. 10). That is, the upper movement restricting portion 139 is arranged with respect to the upper clamp unit 121, and the lower movement restricting portion 140 is arranged with respect to the lower clamp unit 120, on the upstream side of the lower clamp unit 120 and the upper clamp unit 121 in the conveying direction (first conveying direction) of the sheet bundle.

[0082] 9 and 10 , an upstream end surface 120a of the lower clamp unit 120 abuts against the lower movement restricting portion 140. Furthermore, an upstream end surface 121a of the upper clamp unit 121 abuts against the upper movement restricting portion 139. In this embodiment, the lower movement restricting portion 140 and the upper movement restricting portion 139 are rollers having rotation axes in a direction perpendicular to the width direction of the sheet bundle and the conveying direction of the sheet bundle (the up-down direction in FIG. 10 , approximately vertical in this embodiment), respectively, and rotate while abutting against the end surfaces 120a, 121a. As a result, the pressure force applied to the lower clamp unit 120 and the upper clamp unit 121 from the pressure roller 123 restricts the lower clamp unit 120 and the upper clamp unit 121 from moving upstream.

[0083] The leading edge of the sheet bundle conveyed by the third saddle roller pair 118 can be detected by the saddle conveyance sensor 117. By counting from the detection timing of the saddle conveyance sensor 117, the conveyance amount of the sheet bundle can be controlled by the square spine processing control unit 345. In other words, based on the detection result of the saddle conveyance sensor 117, the position of the leading edge of the sheet bundle (the downstream end in the conveyance direction, the spine of the sheet bundle in this embodiment) can be controlled.

[0084] [Upper Clamp Unit and Lower Clamp Unit] The upper clamp unit 121 moves from a receiving position (first position) where it accepts a sheet bundle to a clamp holding position (second position) where it holds the sheet bundle, thereby pressing the sheet bundle against the lower clamp unit 120 and holding the sheet bundle between the upper clamp surface 142 and the lower clamp surface 143. As shown in FIGS. 7A and 7B , the lower clamp unit 120 is fixed to a frame 146 of the square spine processing unit C2 and is fixed via the frame 146 to a support frame included in the housing 27 of the sheet processing device B. The frame 146 includes a front frame and a rear frame made of sheet metal, and a bottom frame connecting the front frame and the rear frame. The lower clamp unit 120 is fixed to each of the front frame and the rear frame. The upper clamp unit 121 is movably supported through through holes formed in the front frame and the rear frame, respectively. At this time, as shown in Figure 16B described later, the leading edge of the sheet stack protrudes by a predetermined protrusion amount P1 from the downstream end faces 120c and 121b of the lower clamp unit 120 and the upper clamp unit 121 in the conveying direction after clamping.

[0085] The upper clamp unit 121 is operated by the square spine processing control unit 345 driving the clamp drive motor 132 (FIGS. 7A and 7B). As shown in FIGS. 7A and 7B, the square spine processing unit C2 further transmits drive power from a clamp drive train 133, which is composed of a pulley, a belt, and a gear train, to a clamp drive link 122, thereby moving the upper clamp unit 121 connected to the clamp drive link 122 in the thickness direction of the sheet stack. Multiple clamp springs 144 that pressurize the sheet stack are built between the clamp drive link 122 and the upper clamp unit 121. While the movement amount of the clamp drive link 122 remains constant, the compression amount of the clamp springs 144 changes depending on the thickness of the sheet stack, thereby changing the pressure. The clamp holding position described above also changes depending on the thickness of the sheet stack. Note that FIG. 7 does not show a movement mechanism for a contact member, which will be described later.

[0086] 16C, the square spine processing unit C2 performs square spine processing by pressing the spine of a sheet bundle held between the lower clamp unit 120 and the upper clamp unit 121 while scanning the sheet bundle widthwise with a pressure roller 123 disposed downstream in the conveying direction, the pressure roller 123 being positioned downstream in the conveying direction. The protrusion amount P1 of the spine of the sheet bundle from the end faces 120c, 121b is determined by the position of a contact member of a skew correction unit, which will be described later.

[0087] When processing square spines, the square spine processing control unit 345 operates the drive motor 135 (FIG. 7B) to move the pressure roller 123. As shown in FIG. 8, the pressure roller 123 is connected to a drive belt 137 arranged in the width direction of the sheet stack, and is movable in the width direction of the sheet stack along a guide rail 120b shown in FIG. 9 (described later). The drive belt 137 rotates by power transmitted from the drive motor 135 via a drive train 136 (FIG. 7B) composed of a gear train. This allows the pressure roller 123 to scan in the width direction of the sheet stack.

[0088] The home positions of the pressure rollers 123 are provided on the front and rear sides of the sheet processing device B. That is, the pressure rollers 123 are moved from the rear side to the front side for the first sheet stack to perform square spine processing, and then the pressure rollers 123 are moved from the front side to the rear side for the second sheet stack to perform square spine processing. A sensor (not shown) is provided at each home position of the pressure rollers 123, making it possible to detect the position of the pressure rollers 123.

[0089] However, a home position may be provided on either the front side or the rear side, and the pressure roller 123 may scan in the width direction from the front side to the rear side or from the rear side to the front side. In this case, for example, after the pressure roller 123 is moved from the rear side to the front side for the first sheet bundle to perform the square spine processing, the pressure roller 123 may be returned from the front side to the rear side, and the pressure roller 123 may also be moved from the rear side to the front side for the second sheet bundle to perform the square spine processing.

[0090] Furthermore, in one round of square spine processing, the pressure roller 123 is moved in one direction, from the front side to the rear side or from the rear side to the front side, but the pressure roller 123 may also be moved back and forth in one round of square spine processing. For example, in one round of square spine processing, whether the pressure roller 123 moves in one direction or back and forth may be set depending on the number and type of sheets included in the sheet stack. This setting may be performed automatically by the control unit, or may be set by an operator such as a user or service technician. Furthermore, in one round of square spine processing, the operator may be able to arbitrarily set whether the pressure roller 123 moves in one direction or back and forth.

[0091] As shown in FIGS. 9 and 10 , the lower clamp unit 120 has a guide rail 120b formed along the width direction of the sheet stack. The lower movement restricting portion 140 engages with the guide rail 120b and moves along the guide rail 120b when the pressure roller 123 moves in the width direction of the sheet stack. The guide rail 120b is formed by combining multiple members and has a generally U-shaped cross section, as shown in FIG. 10 , allowing a portion of the roller-shaped lower movement restricting portion 140 to enter. The lower surface of the outer diameter side of the lower movement restricting portion 140 engages with the lower surface of the guide rail 120b, and the outer peripheral surface of the lower movement restricting portion 140 abuts against the end surface 120a. This restricts movement of the pressure roller 123 in the thickness direction of the sheet stack. The guide rail 120b may be a groove formed in a member upstream of the lower clamp unit 120 in the conveying direction.

[0092] After the square spine treatment is completed, the drive motor 135 (FIG. 7B) is operated to move the pressure roller 123 in the width direction, thereby retracting it from the conveyance path of the sheet bundle, and the clamp drive motor 132 (FIGS. 7A and 7B) is further operated to move the upper clamp unit 121 in a direction away from the sheet bundle (FIG. 16D, which will be described later). This allows the sheet bundle to be conveyed further downstream. It is also possible to discharge the sheet bundle without performing the square spine treatment described above.

[0093] [Discharge Section] As shown in Figure 2, the sheet bundle that has passed through the saddle section B2 is conveyed by the saddle third roller pair 118 toward a saddle discharge guide 124 that is disposed further downstream in the first conveyance direction than the pressure roller 123. The saddle discharge guide 124 is supported so as to be swingable about a first fulcrum 124b having a rotation axis parallel to the rotation axes of the rollers of the saddle third roller pair 118. The first fulcrum 124b is located above a line extending downstream in the conveyance direction of the sheet bundle by the saddle third roller pair 118 (first conveyance direction, saddle third roller conveyance direction 118c). The saddle discharge guide 124 is disposed so as to hang vertically downward from the first fulcrum 124b.

[0094] The upstream side of the saddle discharge guide 124 in the first transport direction is inclined vertically from the first fulcrum 124b toward the intermediate portion 124a toward the upstream side in the first transport direction. The upstream side of the saddle discharge guide 124 in the first transport direction is inclined vertically from the intermediate portion 124a toward the lower end toward the downstream side in the first transport direction. That is, the upstream side of the saddle discharge guide 124 in the first transport direction is curved so that the intermediate portion 124a in the vertical direction protrudes further upstream in the first transport direction than the other portions. A guide surface 124d is provided on the upstream side of the saddle discharge guide 124 in the first transport direction between the intermediate portion 124a and the lower end.

[0095] The guide surface 124d is located below a line extending downstream in the saddle third roller conveying direction 118c, and comes into contact with the sheet stack conveyed by the saddle third roller pair 118, guiding the sheet stack downward. The saddle discharge guide 124 is rotatable about the first fulcrum 124b when the sheet stack comes into contact with the guide surface 124d. Note that depending on the rigidity of the sheet stack, the saddle discharge guide 124 may not come into contact with the guide surface 124d of the saddle discharge guide 124, and even if it does come into contact, the amount of rotation varies depending on the rigidity, so the saddle discharge guide 124 does not necessarily rotate.

[0096] A second fulcrum 124c is provided at the lower end of the saddle ejection guide 124, and a saddle ejection roller 125 (described later) is connected to the second fulcrum 124c so as to be rotatable about the second fulcrum 124c. The second fulcrum 124c is located below the guide surface 124d and has a rotation axis parallel to the rotation axis of the first fulcrum 124b.

[0097] As the sheet bundle continues to be conveyed by the third saddle roller pair 118, it is delivered to a saddle discharge unit 131 that is disposed downstream of the square spine processing unit 134 in the first conveyance direction and vertically below the saddle discharge guide 124. The saddle discharge unit 131 has a saddle discharge upstream belt 127, a saddle discharge upstream sensor 128, a saddle discharge downstream belt 129, and a saddle discharge downstream sensor 130.

[0098] The saddle discharge upstream belt 127 is located below the guide surface 124d of the saddle discharge guide 124 and guides and transports the sheet bundle guided downward by the guide surface 124d further downstream. The saddle discharge upstream belt 127 is inclined so that it slopes vertically downward as it moves downstream in the transport direction. The saddle discharge downstream belt 129, which serves as a sheet bundle discharge section, receives the sheet bundle transported from the saddle discharge upstream belt 127 and guides and transports it further downstream. The saddle discharge downstream belt 129 is inclined so that it slopes vertically upward as it moves downstream in the transport direction. Therefore, the sheet bundle guided by the guide surface 124d to the saddle discharge upstream belt 127 is transported in a direction inclined vertically downward by the saddle discharge upstream belt 127, and then transported in a direction inclined vertically upward by the saddle discharge downstream belt 129.

[0099] In addition, a saddle discharge upstream sensor 128 that detects the sheet stack on the upstream side is arranged on the upstream side within the conveyable area of ​​the saddle discharge upstream belt 127, and a saddle discharge downstream sensor 130 that detects the sheet stack on the downstream side is arranged on the upstream side within the conveyable area of ​​the saddle discharge downstream belt 129.

[0100] The sheet bundle delivered to the saddle discharge unit 131 is stacked while being transported by the saddle discharge upstream belt 127 and the saddle discharge downstream belt 129. The saddle discharge upstream belt 127 nip the sheet bundle at a nip point between it and the saddle discharge roller 125 described above on the downstream side in the transport direction. The sheet bundle present on the saddle discharge upstream belt 127 is configured to suppress opening of the opening side (fore-edge side) at this nip point. The position of this nip point can be changed around the second fulcrum 124c depending on the thickness of the sheet bundle.

[0101] While the succeeding sheet bundle is being processed, the preceding sheet bundle is conveyed upstream in the conveying direction by the saddle discharge upstream belt 127 and stopped at a predetermined conveyance distance after being detected by the saddle discharge upstream sensor 128 or the saddle discharge downstream sensor 130. This conveyance distance is a position that can prevent the opening side of the preceding sheet bundle from opening at the nip point with the saddle discharge roller 125, and is positioned so that the succeeding sheet bundle comes into contact with the upper surface of the preceding sheet bundle when it is discharged. That is, in this embodiment, the succeeding sheet bundle is stacked on top of the preceding sheet bundle in the saddle discharge unit 131 (in a so-called tiled manner).

[0102] In this way, the saddle discharge unit 131 discharges the succeeding sheet bundle onto the top surface of the preceding sheet bundle without entering the opening of the preceding sheet bundle, and the succeeding sheet bundle is stably stacked in a tiled manner without causing any problems such as getting caught, curling, or being pushed out of the preceding sheet bundle.

[0103] The saddle discharge port 126 is disposed downstream of the saddle discharge guide 124 in the first conveying direction and between the saddle discharge upstream belt 127 and the saddle discharge downstream belt 129. The sheet bundle conveyed to the saddle discharge unit 131 passes through the saddle discharge port 126 and is discharged to the outside of the sheet processing apparatus B, making it easier for the user to access the discharged sheet bundle.

[0104] If another device is present downstream of the saddle discharge unit 131, it is also possible to transfer the sheet bundle to the downstream device by continuing conveyance without stacking. In this embodiment, a discharge cover 151 serving as a cover member is provided on the outside of the saddle discharge port 126. The discharge cover 151 is positioned so as not to prevent the sheet bundle from being discharged from the saddle discharge port 126, and is positioned so as not to allow an operator such as a user to access the inside of the device through the saddle discharge port 126.

[0105] [Skew Correction of Sheet Bundle] Next, skew correction of a sheet bundle performed before square spine processing of the sheet bundle in this embodiment will be described with reference to Figures 11 to 15D. A sheet bundle that has been saddle-stitched by the saddle-stitching processing unit 104 and center-folded by the center-folding processing mechanism C1 may be transported in a skewed state due to the influence of component tolerances in each component.

[0106] When square spine processing is performed by the square spine processing unit C2 with the sheet bundle skewed, the amount of protrusion of the spine of the sheet bundle downstream from the downstream end faces 121b and 120c in the conveying direction of the upper clamp unit 121 and the lower clamp unit 120 varies in the width direction. In this state, if the spine of the sheet bundle is pressed by the pressure roller 123, the finish during square spine processing will be uneven in the width direction of the sheet bundle, and there is a risk that the user will not be able to provide the desired product.

[0107] Therefore, in this embodiment, skew of the sheet bundle is corrected before square spine processing is performed on the sheet bundle. The configuration of the skew correction unit 500 will be described below with reference to FIGS. 11 to 14B. FIG. 11 is a diagram illustrating the skew correction unit that corrects skew of the sheet bundle. FIG. 11 is a perspective view of the square spine processing unit 134 as viewed from the upstream side of the third saddle roller pair 118 in the conveying direction. The skew correction unit 500 has a contact member (regulating portion) 501 that contacts the spine of the sheet bundle, and a movement mechanism 510 (an example of a second movement mechanism) that raises the contact member 501 from a retracted position and moves it to a pressing position where it can contact the sheet bundle.

[0108] 12A to 12C are diagrams showing a state in which the abutting member 501 is located at the retracted position, in which Fig. 12A is a perspective view of the skew correction unit 500, Fig. 12B is a diagram showing the skew correction unit 300 as seen from the downstream side in the conveying direction of the sheet bundle, and Fig. 12C is a schematic cross-sectional view of the square spine processing unit 134. As shown in Figs. 11 and 12A to 12C, the moving mechanism 510 is provided vertically below the lower clamp unit 120 and the upper clamp unit 121.

[0109] 12C , the contact member 501 is located below the lower clamp unit 120. The contact member 501 located at the retracted position is retracted below the pressure roller 123 so as not to obstruct the movement of the pressure roller 123. When the contact member 501 is located at the retracted position, the pressure roller 123 can move in the width direction of the sheet stack. In other words, when the contact member 501 is located at the retracted position, the square spine processing unit 134 can perform square spine processing.

[0110] Next, the movement mechanism (adjustment unit) 510 that moves the abutting member 501 in a predetermined direction, including the sheet bundle transport direction and the direction opposite to the transport direction, will be described with reference to FIGS. 12A to 13C. FIGS. 13A to 13C show a state in which the abutting member 501 is lifted. FIG. 13A is a perspective view of the skew correction unit 500, FIG. 13B is a view of the skew correction unit 500 as seen from the downstream side in the sheet bundle transport direction, and FIG. 13C is a schematic cross-sectional view of the square spine processing unit 134. As shown in FIG. 13B, in the raised position, the abutting member 501 can abut against the spine of a sheet bundle that has passed between the lower clamp unit 120 and the upper clamp unit 121, which are spaced apart. In other words, when the lower clamp unit 120 and the upper clamp unit 121 are open, the abutting member 501 is positioned to partially block the open area between the lower clamp unit 120 and the upper clamp unit 121.

[0111] The abutting member 501 can be raised from the retracted position shown in FIGS. 12A to 12C to the raised position shown in FIGS. 13A to 13C by swinging the link mechanisms 502a and 502b using the movement mechanism 510. The movement of the abutting member 501 from the retracted position to the raised position is driven by the motor 511. First, the motor 511 is driven, causing the drive pulley 511a of the motor 511 to rotate in the direction of the arrow in FIG. 12A. Then, the gear 513 rotates in the direction of the arrow in FIG. 12A via the gear train 512, causing the shaft 513a to rotate together with the gear 513, and the link mechanism 502a connected to the shaft 513a to rotate around the rotation center 502aa. As the link mechanism 502a rotates, the abutting member 501 is lifted while rotating in the direction along the movement direction of the clamp member around the rotation center 502ab. Then, the link mechanism 502b rotates together with the link mechanism 502a around the rotation center 502ba via the rotation center 502bb of the abutting member 501, and the abutting member 501 is raised to a predetermined position while being supported by the link mechanisms 502a and 502b. When the abutting member 501 is in the raised position, the abutting member 501 is supported by the link mechanisms 502a and 502b. When the motor 511 rotates in the reverse direction, the respective gears rotate in the direction opposite to the arrow direction described above, and the abutting member 501 can be moved from the raised position to the retracted position.

[0112] In this way, the link mechanisms 502a and 502b enable the abutting member 501 to move from the raised position to the retracted position. As a result, the link mechanisms 502a and 502b do not move downward below the moving mechanism 510, and therefore there is no need to provide a space to accommodate the link mechanisms below the drive unit. Therefore, compared to a configuration in which movement from the raised position to the retracted position is performed using a rack and gears, no space is required to accommodate the rack when the abutting member 501 is in the retracted position, making it possible to reduce the size of the device in the vertical direction (the direction in which the clamp moves).

[0113] Furthermore, even if, as in this embodiment, the moving mechanism 510 for operating the abutment member 501 cannot be positioned so as to overlap with the abutment member 501 in the width direction (the movement direction of the pressure roller 123) due to the arrangement of other units, it is possible to move the abutment member 501 in a direction along the movement direction of the clamp by using link mechanisms 502a and 502b.

[0114] In this embodiment, the link mechanisms 502a and 502b use a linear link between the moving mechanism 510 and the abutting member 501, but a two-stage extension structure may be used by providing a joint. In this case, the two link mechanisms may not be driven in the same direction, but may extend and contract symmetrically. This also makes it possible to reduce the vertical space required for movement compared to a structure in which a rack is used to move the abutting member 501 from the abutting position to the retracted position.

[0115] When the abutting member 501 is moved to the raised position by the movement mechanism 510, it can move toward and away from the lower clamp unit 120 and the upper clamp unit 121. This allows the abutting member 501 to move to a position that restricts the amount of protrusion of the sheet bundle from the clamping position of the lower clamp unit 120 and the upper clamp unit 121. After receiving the sheet bundle (after abutting against the sheet bundle), the abutting member 501 further moves toward the lower clamp unit 120 and the upper clamp unit 121, and as it moves, it pushes back the spine of the sheet bundle, thereby correcting skew of the sheet bundle (correction of skew of the sheet bundle will be described later).

[0116] With the abutting member 501 raised to the raised position, the movement mechanism 510 slides the link mechanisms 502a and 502b together with the support shaft, thereby enabling the abutting member 501 to move toward and away from the lower clamp unit 120 and the upper clamp unit 121. The structure for sliding the abutting member 501 together with the link mechanisms 502a and 502b is driven by a motor 514. For the sake of explanation, the operation related to driving will be described using FIG. 12A, but the sliding movement of the abutting member 501 is performed with the abutting member 501 raised to a predetermined position (the position shown in FIGS. 13A to 13C).

[0117] First, the motor 514 is driven to rotate the drive pulley 514a of the motor 514 in the direction of the arrow in FIG. 12A . Then, the gear 516 rotates in the direction of the arrow in FIG. 12A via the gear train 515, causing the slide rack 517 to move toward the lower clamp unit 120 and the upper clamp unit 121. The slide sheet metal 518 connected to the slide rack 517 also moves as the slide rack 517 moves. The link mechanisms 502a and 502b are connected to the slide sheet metal 518 via shafts (not shown). Therefore, as the slide sheet metal 518 slides, the abutment member 501 supported by the link mechanisms 502a and 502b moves toward the lower clamp unit 120 and the upper clamp unit 121. When the motor 514 rotates in the reverse direction, the gears rotate in the opposite direction to the arrows, allowing the slide sheet metal 518 to slide in the reverse direction.

[0118] As described above, the movement mechanism 510 can push back the spine of the sheet stack in the direction opposite to the conveying direction by moving the contact member 501 from the retracted position to the raised position and further from the raised position in a direction approaching the lower clamp unit 120 and the upper clamp unit 121. At this time, the sheet stack is pushed back by the contact member 501, and follows the contact member 501, thereby correcting skew. At this time, the contact member 501 corrects skew of the sheet stack by contacting at least two points on the spine of the sheet stack. In this embodiment, the contact member 501 is plate-shaped, but it may be two members as long as they can correct skew by contacting at least two points.

[0119] The position at which the sliding movement of the abutting member 501 is stopped by the moving mechanism 510 is a position at which the spine of the sheet stack protrudes downstream in the first conveyance direction beyond the end faces 121b, 120c of the lower clamp unit 120 and the upper clamp unit 121. In this way, the stopping position of the abutting member 501 determines the amount by which the spine of the sheet stack protrudes beyond the end faces 121b, 120c of the lower clamp unit 120 and the upper clamp unit 121. Figures 14A and 14B are diagrams showing the stopped state after the abutting member 501 has slid toward the lower clamp unit 120 and the upper clamp unit 121. Figure 14A is a perspective view of the skew correction unit 500, and Figure 14B is a schematic cross-sectional view of the skew correction unit 500.

[0120] As the sliding metal plate 518 slides, the shaft 513a, which is connected to rotate the link mechanisms 502a, b, also slides from the state shown in Fig. 13A to the state shown in Fig. 14A. Here, the gear 512a of the gear train 512, which meshes with the gear 513, is longer than the gear 513 in the direction of the rotation axis, so that the sliding metal plate 518 can be slid while the gear 513 and the gear 512a are meshed with each other. Therefore, the sliding metal plate 518 can be slid without releasing the meshing between the gear train 512 and the gear 513.

[0121] Furthermore, the distance between the lower clamp unit 120 and the upper clamp unit 121 and the abutment member 501 is determined based on the position at which the abutment member 501 stops. The amount of protrusion of the spine of the sheet bundle when the sheet bundle is clamped by the lower clamp unit 120 and the upper clamp unit 121 is regulated based on the position of the abutment member 501 here. For example, depending on the number of sheets in the sheet bundle and the material of the sheets, the position of the abutment member 501 is specified so that the amount of protrusion is increased when the stiffness of the sheet bundle is high compared to when the stiffness of the sheet bundle is low. In this way, by controlling the position of the abutment member 501 using parameters that determine the amount of protrusion of the spine of the sheet bundle based on information about the sheet bundle, it is possible to perform square spine processing well even on sheet bundles with high stiffness that are difficult to square spine process.

[0122] However, with this configuration, the relative position of the contact member 501 relative to the lower clamp unit 120 and the upper clamp unit 121 when raised to the contact position may vary from device to device due to dimensional tolerances of components, etc. In this case, even if the position of the contact member 501 is controlled using parameters, etc., to achieve a protrusion amount corresponding to the sheet stack information, it may not be moved to the desired position due to individual differences in components, etc., between devices. For example, the position of the contact member 501 when raised may be 0.8 mm away from the clamp members in device A, or 0.5 mm away from the clamp members in device B. In this case, if the same control is implemented for each device, there is a risk that the strength of the spine processing may differ between device A and device B. In this case, the user may not be able to obtain the desired result. In other words, the dimensional tolerances of the components constituting the device may cause the contact member 501 to deviate from the ideal design position, potentially resulting in an undesired result for the user.

[0123] Therefore, this embodiment has an adjustment mode for adjusting the initial position of the contact member 501 relative to the lower clamp unit 120. The initial position adjustment operation of the contact member 501, skew correction of the sheet stack, and protrusion amount adjustment will be described below.

[0124] 15A to 15D are schematic cross-sectional views illustrating the operation of adjusting the amount of spine protrusion by correcting skew of a sheet bundle after adjusting the initial positions of the abutting member 501 and the lower clamp unit 120. FIG. 15A illustrates a state in which the initial positions of the abutting member 501 and the lower and upper clamp units 120 and 121 are being adjusted. FIG. 15B illustrates a state in which the abutting member 501 has moved from the adjusted initial position to the pressing position. FIG. 15C illustrates a state in which the abutting member 501 has moved to the pressing position and accepted the sheet bundle. FIG. 15D illustrates a state in which the abutting member 501 has moved from the pressing position toward the lower and upper clamp units 120 and 121. In this embodiment, the pressing position of the abutting member 501 refers to a position away from the lower and upper clamp units 120 and 121 by a distance calculated by adding the amount of movement required to correct skew of the sheet bundle and the amount of spine protrusion based on information about the sheet bundle. In this embodiment, the pressing position refers to a position based on information about the sheet bundle.

[0125] As shown in FIG. 15A , the abutment member 501 is lifted to a raised position by the link mechanisms 502 a and 502 b as shown in FIGS. 13A to 13C , and then moved by the moving mechanism 510 so as to be pressed against the lower clamp unit 120 and the upper clamp unit 121, thereby adjusting the initial position. At this time, the moving mechanism 510 moves the abutment member 501 15 mm from the state in which the abutment member 501 is positioned at the abutment position toward the clamps so that the abutment member 501 is sufficiently pressed against the lower clamp unit 120 and the upper clamp unit 121 and the distance becomes zero. Here, because the moving mechanism 510 includes a torque limiter, the motor 514 can continue to be driven while the abutment member 501 is in abutment with the clamps, allowing the abutment member 501 to be pressed against the clamps. In this way, by pressing the abutment member 501 against the lower clamp unit 120 and the upper clamp unit 121, the initial positions of the abutment member 501 and the lower clamp unit 120 are adjusted to a position following the side surfaces of the clamps.

[0126] In this embodiment, the abutting member 501 is brought into contact with the lower clamp unit 120 and the upper clamp unit 121 when they are open. However, the reference position may be adjusted by bringing the abutting member 501 into contact with either the lower clamp unit 120 or the upper clamp unit 121 when they are closed. The initial position may be adjusted by bringing the abutting member 501 into contact with either the lower clamp unit 120 or the upper clamp unit 121. In this case, the initial position is adjusted relative to the lower clamp unit 120, which is fixed to the frame of the square spine processing unit C2, rather than the movable upper clamp unit 121, thereby further reducing the influence of component tolerances. Furthermore, by configuring the lower clamp unit 120 to be positioned closer to the abutting member 501 on the contact surfaces of the upper clamp unit 121 and the lower clamp unit 120, even when the component dimensional tolerances are maximized, the initial positions of the abutting member 501 and the lower clamp unit 120 can be more effectively adjusted.

[0127] 15B, after the initial position is adjusted, the contact member 501 moves and stops in a direction away from the lower clamp unit 120 and the upper clamp unit 121. The square spine processing unit 134 receives the sheet bundle in this state.

[0128] The sheet bundle that has been saddle-stitched and center-folded (the sheet bundle folded in half with the crease bound) is conveyed in the direction of the arrow in Fig. 15C by the second saddle roller pair 115 and the third saddle roller pair 118. Then, in response to the detection of the leading edge (spine) of the sheet bundle by the saddle conveyance sensor 117, the second saddle roller pair 115 and the third saddle roller pair 118 convey the sheet bundle by a predetermined distance and then stop conveying.

[0129] Thereafter, the conveyance control unit 342 controls a separation mechanism (an example of a first movement mechanism) (not shown) to separate the second saddle roller pair 115 and the third saddle roller pair 118 from each other, thereby releasing the sheet bundle from its grip. In this state, the aforementioned movement mechanism 510 moves the contact member 501 in the direction of the arrow shown in FIG. 15D . The movement of the contact member 501 at this time brings the contact member 501 into contact with the spine of the sheet bundle. Then, the contact member 501 moves in the direction of the arrow in FIG. 15D while in contact with the spine of the sheet bundle, thereby pushing the sheet bundle back in the direction opposite to the conveyance direction.

[0130] The sheet stack is pushed back while in contact with the abutting member 501, so that the spine follows the abutting member 501 and the skew is corrected. In the state shown in FIG. 15D , the saddle second roller 115a and the saddle third roller 118a, which are located on the lower side in the vertical direction, are spaced apart to a position lower than the second post-fold path lower guide 114a, the second roller post-path lower guide 116a, and the clamp front lower guide portion 119a. The saddle third roller 118a is an example of a first conveying means, the saddle third roller 118b is an example of a second conveying means, and the pair of saddle third rollers 118 is an example of a conveying portion that conveys the sheet stack to the square spine processing portion C2.

[0131] Therefore, when the sheet bundle is pushed back by the contact member 501, it does not come into contact with the saddle second roller 115a and the saddle third roller 118a. The second post-fold path lower guide 114a, the second roller post-path lower guide 116a, and the clamp front lower guide portion 119a are all made of sheet metal, and the surface friction of the guide surface of the second roller post-path lower guide 116a that guides the sheet bundle is approximately one-tenth that of the saddle second roller 115a and the saddle third roller 118a, which have a conveying force. This allows the sheet bundle to move in the direction opposite to the conveying direction without load. As described above, in this embodiment, compared to a configuration in which skew of the sheet bundle is corrected by continuing conveyance by the conveyor belt while the sheet bundle is in contact with the contact member, damage to the cover of the sheet bundle can be suppressed because the sheet bundle does not come into contact with a member having a conveying force during skew correction.

[0132] Note that the same effect can be obtained if the portion having the conveying force to convey the sheet bundle can be positioned below the second roller post-path lower guide 116a, which is a conveying guide. In order to obtain the above effect, the portions that do not directly convey the sheet bundle and are not positioned to obstruct the conveyance of the sheet bundle, such as the portions that support the saddle second roller 115a and the saddle third roller 118a, may be positioned above the second roller post-path lower guide 116a, the clamp front lower guide portion 119a, or the second post-fold path lower guide 114a.

[0133] 15D, the contact member 501 stops at a position where the amount of protrusion of the spine of the sheet bundle from the lower clamp unit 120 and the upper clamp unit 121 is a predetermined amount determined based on information about the sheet bundle. In this state, the sheet bundle is sandwiched between the lower clamp unit 120 and the upper clamp unit 121. At this time, the second saddle roller pair 115 and the third saddle roller pair 118 also release their separated state to sandwich the sheet bundle. Thereafter, the movement mechanism 510 retracts the contact member 501 to the retracted position shown in FIGS. 12A to 12C, and the pressure roller 123 moves in the width direction of the sheet bundle, thereby enabling square spine processing to be performed on the sheet bundle after skew correction.

[0134] As described above, in this embodiment, the contact member 501 is adjusted to its initial position relative to the clamp by conforming to the side surfaces of the lower clamp unit 120 and the upper clamp unit 121, and then moved to a regulating position for regulating the amount of protrusion of the spine of the sheet bundle. This improves the positional accuracy of the regulating position of the regulating unit that regulates the amount of protrusion of the spine of the sheet bundle from the clamp position. Furthermore, even in a configuration in which the amount of protrusion of the spine is determined based on parameters calculated in advance according to the thickness of the sheet bundle, the contact member 501 can be moved to a targeted position, making it possible to perform better square spine processing.

[0135] [Control of Square Spine Processing] Next, the control of square spine processing in this embodiment will be described with reference to Figures 16A to 16D. As described above, the square spine processing unit C2 performs square spine processing to add a corner to the spine of the sheet bundle whose skew has been corrected by the skew correction unit 500. In this embodiment, the center-folding control unit 344 shown in Figure 3 controls each conveying roller pair, namely, the folding roller pair 113, the second saddle roller pair 115, and the third saddle roller pair 118, with the same drive.

[0136] The center folding control unit 344 is triggered by the detection of the leading edge of the sheet stack Sb by the saddle conveyance sensor 117 to perform the skew correction operation by the above-described skew correction unit 500. Then, as shown in FIG. 16A , the center folding control unit 344 stops the return operation of the sheet stack Sb by the abutting member 501 in a state in which the spine Ssp of the sheet stack Sb protrudes further downstream in the first conveyance direction than the downstream end faces 121 b and 120 c of the upper clamp unit 121 and the lower clamp unit 120 in the first conveyance direction.

[0137] In this state, the square spine processing control unit 345 drives the clamp drive motor 132 (FIGS. 7A and 7B) to move the upper clamp unit 121 toward the lower clamp unit 120, and as shown in FIG. 16B, the sheet bundle Sb is clamped by the upper clamp unit 121 and the lower clamp unit 120. At this time, the spine Ssp of the sheet bundle Sb protrudes downstream by an amount P1 beyond the end faces 121b and 120c of the upper clamp unit 121 and the lower clamp unit 120 on the downstream side in the first conveyance direction.

[0138] Next, the square spine processing control unit 345 operates the drive motor 135 (FIG. 7B) to move the pressure roller 123 in the width direction of the sheet bundle Sb. At this time, as shown in FIG. 16C, the pressure roller 123 moves in the width direction while pressing the spine Ssp of the sheet bundle Sb, thereby subjecting the spine Ssp of the sheet bundle Sb to square spine processing. Thereafter, as shown in FIG. 16D, the square spine processing control unit 345 drives the clamp drive motor 132 (FIGS. 7A and 7B) to separate the upper clamp unit 121 from the lower clamp unit 120, thereby releasing the clamping of the sheet bundle Sb. This completes the square spine processing, and the sheet bundle Sb is discharged as described above.

[0139] In this manner, in the present embodiment, since the square spine processing is performed on the sheet bundle after correcting the skew of the sheet bundle, it is possible to perform the square spine processing uniformly across the width of the sheet bundle. Also, compared to a configuration in which the skew of the sheet bundle is corrected by continuing the conveyance of the conveyor belt while the sheet bundle is in contact with an abutting member, the sheet bundle does not come into contact with a member having a conveying force during the skew correction, so that it is possible to prevent damage to the cover of the sheet bundle.

[0140] [Control flow of skew correction processing and square spine processing] Next, an example of the control flow of the skew correction processing and square spine processing described above will be described with reference to Fig. 17. In the control flow of Fig. 17, each unit is controlled by the saddle control unit 350 shown in Fig. 3.

[0141] First, in response to the entrance sensor 190 detecting that a sheet has been conveyed to the saddle portion B2 (S1: Y), the aforementioned movement mechanism 510 adjusts the initial position of the contact member 501 relative to the upper clamp unit 121 and the lower clamp unit 120 (S2). Thereafter, the movement mechanism 510 moves the contact member 501 from the position where it abuts against the lower clamp unit 120 and the upper clamp unit 121 to a regulating position ( FIGS. 13A and 13B ) away from the lower clamp unit 120 and the upper clamp unit 121 by a distance calculated by adding the amount of movement required to correct skew of the sheet bundle and the amount of spine protrusion based on information about the sheet bundle (S3). Then, in response to the saddle conveyance sensor 117 detecting the sheet bundle (S4: Y), the sheet bundle that has been saddle-stitched and center-folded is conveyed by the saddle second roller pair 115 and the saddle third roller pair 118 for a predetermined time (S5: Y), and then conveyance is stopped (S6). At this time, the conveyance of the sheet stack is stopped at a position where the spine of the sheet stack protrudes from the downstream end faces (hereinafter, clamp ends) of the upper clamp unit 121 and the lower clamp unit 120 in the conveying direction. In this embodiment, after the sheet stack is detected by the saddle conveyance sensor 117, the sheet stack is conveyed at 175 mm / s and then conveyance is stopped so that the spine of the sheet stack protrudes 12 mm from the downstream end faces of the upper clamp unit 121 and the lower clamp unit 120 in the conveying direction.

[0142] In this state, the second saddle roller pair 115 and the third saddle roller pair 118 are separated from each other as shown in Fig. 15C (S7). Then, the contact member 501 is moved in the opposite direction to the conveying direction as shown in Fig. 15D (S8). In this embodiment, the sheet bundle is pushed back in the opposite direction to the conveying direction by the contact member 501 to a position where the spine of the sheet bundle protrudes 4 mm from the end faces of the upper clamp unit 121 and the lower clamp unit 120 on the downstream side in the conveying direction. The above position is, for example, when the sheet bundle has a weight of 80 g / m ２ In this example, the sheet stack is made up of 30 sheets of 1000 x 1000 mm. After the sheet stack is pushed back by the contact member 501, the amount of protrusion from the end faces of the upper clamp unit 121 and the lower clamp unit 120 on the downstream side in the conveying direction may be variable depending on the number of sheets and the basis weight of the sheet stack.

[0143] When moving the abutting member 501 in S2, as described above, the motor 511 is first rotated in the forward direction to swing the link mechanisms 502a and 502b, thereby moving the abutting member 501 from the retracted position to the raised position. Then, the motor 514 is rotated in the forward direction to slide the sliding metal plate 518 toward the upper clamp unit 121 and the lower clamp unit 120, thereby adjusting the initial position. Then, in S3, the motor 514 is rotated in the reverse direction to slide the sliding metal plate 518 away from the upper clamp unit 121 and the lower clamp unit 120, thereby moving the abutting member 501 to the pressing position. Then, in S8, the motor 514 is rotated in the forward direction to slide the sliding metal plate 518 toward the upper clamp unit 121 and the lower clamp unit 120, thereby causing the abutting member 501 to push back the sheet bundle.

[0144] In this state, the sheet stack is clamped by the upper clamp unit 121 and the lower clamp unit 120 (S9), and then the sheet stack is clamped by the second saddle roller pair 115 and the third saddle roller pair 118 (S10).

[0145] Then, with the sheet stack sandwiched between the clamps and the respective pairs of conveying rollers, the abutting member 501 is moved to the retracted position (S11). Here, when moving the abutting member 501 to the retracted position, first, the motor 514 is rotated in the reverse direction to slide the slide metal plate 518 in a direction away from the upper clamp unit 121 and the lower clamp unit 120, thereby moving the abutting member 501 away from the upper clamp unit 121 and the lower clamp unit 120. Thereafter, the motor 511 is rotated in the reverse direction to swing the link mechanisms 502a and 502b, thereby moving the abutting member 501 from the pressing position to the retracted position.

[0146] Then, the pressure roller 123 presses the spine of the sheet stack toward the upper clamp unit 121 and the lower clamp unit 120 while moving in the width direction of the sheet stack (in the direction of the rotation axis of the saddle third roller pair 118 and along the fold of the sheet stack), thereby performing square spine processing on the sheet stack (S12).

[0147] The saddle control section 350 then releases the sheet bundle from the clamping by the upper clamp unit 121 and the lower clamp unit 120 (S13), and then discharges the sheet bundle that has been subjected to the square spine processing (S14).

[0148] In this manner, in this embodiment, by adjusting the initial position of the contact member 501 relative to the clamp member and then moving the contact member 501 to a regulating position based on information about the sheet bundle, the amount of spine protrusion from the clamp can be more accurately regulated, thereby enabling satisfactory square spine processing. Also, by performing square spine processing after correcting the skew of the sheet bundle, square spine processing can be performed more uniformly across the width of the sheet bundle, thereby improving the quality of the finished product.

[0149] Other Embodiments In the above-described embodiment, skew correction of the sheet bundle is performed by pushing back the spine of the sheet bundle with the contact member 501. However, skew correction may be performed by continuing the conveyance of the sheet bundle by the conveyor belt while the contact member 501 is positioned at the pressing position. In other words, instead of correcting skew by pushing back the sheet bundle with the contact member 501, skew correction may be performed by pressing the sheet bundle against the contact member 501. Even with this configuration, the relative position of the contact member 501 may be adjusted as described above, and then the contact member 501 may be moved to a restricting position that restricts the protrusion amount of the sheet bundle, and the conveyor belt may convey the sheet bundle so as to press the sheet bundle at the restricting position. Even with this configuration, the control of this embodiment can be used to more accurately control the protrusion amount of the spine from the clamp, thereby enabling satisfactory square spine processing.

[0150] In the above-described embodiment, a configuration has been described in which the relative position between the abutting member 501 and the clamp is adjusted by directly pressing the abutting member 501 against the lower clamp unit 120 (and the upper clamp unit 121), but other configurations are possible as long as the relative position can be adjusted. For example, the relative position between the abutting member 501 and the clamp may be indirectly adjusted by pressing the abutting member 501 against a metal plate or the like fixed to the lower clamp unit 120. Alternatively, a sensor may be fixed to the lower clamp unit 120, and the relative position may be adjusted in response to detection of the position of the abutting member 501 by the sensor.

[0151] In the above-described configuration, the retracted position of the abutting member 501 is vertically below the abutting position, but the retracted position may be vertically above the abutting position as long as the moving mechanism 510 is configured to be located above the clamp. Even in this configuration, it is possible to achieve a more compact device in the movement direction of the clamp compared to a configuration in which the abutting member 501 is moved using a rack.

[0152] In the above-described embodiment, a pair of conveying rollers is used as a conveying means for conveying the sheet bundle that has been saddle-stitched and center-folded, but a conveying belt may be used for conveying the sheet bundle. Alternatively, a conveying means that forms a conveying nip with a conveying belt and conveying rollers may be used for conveying the sheet bundle. Even in this configuration, the conveying load can be reduced by pushing back the sheet bundle with the abutting member 501 while the roller or belt having a conveying force is retracted below (or above) the conveying guide, thereby preventing damage to the cover of the sheet bundle during skew correction.

[0153] In the above-described embodiment, the square spine processing is performed downstream inside the saddle unit B2 in the sheet processing device B. However, the same square spine processing may be performed in a separate housing externally connected to the housing in which the saddle unit B2 is provided. For example, a single unit may be provided that performs only the square spine processing without performing saddle stitching or center folding. In this case, the unit includes the square spine processing unit C2 described above and a conveying means such as a conveying roller pair that conveys the sheet bundle that has been saddle stitched and center folded to the square spine processing unit C2.

[0154] Furthermore, in the above-described embodiment, the sheet processing device B has a control unit that controls each internal configuration of the sheet processing device B, but each internal configuration of the sheet processing device B may also be configured to be controlled by a control unit provided in the image forming device.

[0155] In the above embodiment, the retracted position of the contact member 501 is below the lower clamp unit 120, but the retracted position may be set above the upper clamp unit 121. In this case, the moving mechanism 510 or the like may be provided above the square spine processing section C2. The retracted position of the contact member 501 is not limited to being above or below the clamp unit, and may be set to any position as long as it does not interfere with the movement of the pressure roller 123 when the contact member 501 is positioned at the retracted position.

[0156] Furthermore, in the above embodiment, the image forming system 1000 in which the sheet processing apparatus B is directly connected to the image forming apparatus A has been described, but other system configurations are also possible. For example, a configuration in which another processing apparatus, a conveying apparatus, etc. is connected between the image forming apparatus A and the sheet processing apparatus B may be used. Furthermore, in the above embodiment, the image forming apparatus A is described as forming a monochrome image using toner, but the image forming apparatus may be an image forming apparatus that forms a color image using toner, or an image forming apparatus that forms an image on a sheet using ink.

[0157] Summary of the present disclosure The present disclosure includes aspects described in the following items: (Item 1) A sheet processing device including: a conveying unit that conveys a folded sheet bundle bound at a crease; a clamping unit that clamps the sheet bundle conveyed by the conveying unit at a clamping position; and a pressing unit that presses the sheet bundle, the square spine processing unit performing a square spine treatment on the spine of the sheet bundle by moving the pressing unit along the crease of the sheet bundle clamped by the clamping unit; a restricting unit that restricts an amount of protrusion of the sheet bundle from the clamping position by hitting the spine of the sheet bundle when moving from an initial position to a restricting position; and an adjusting unit that pre-adjusts the initial position of the restricting unit with respect to the clamping position each time the square spine treatment is performed. (Item 2) The sheet processing apparatus according to item 1, wherein the regulating unit is movable in a direction toward the clamp unit and a direction away from the clamp unit, and the adjustment unit moves the regulating unit in a direction toward the clamp unit to adjust the initial position, and then moves the regulating unit in a direction away from the clamp unit to the regulating position based on information about the sheet stack transported by the transport unit. (Item 3) The sheet processing apparatus according to item 2, wherein the adjustment unit abuts the regulating unit against the clamp unit when adjusting the initial position. (Item 4) The sheet processing apparatus according to item 3, wherein the clamp unit includes a fixed first clamp and a second clamp that is movable in a direction toward the first clamp and a direction away from the first clamp and clamps the sheet stack together with the first clamp, and the adjustment unit abuts the regulating unit against the first clamp when adjusting the initial position. (Item 5) The sheet processing apparatus according to item 1, wherein the adjustment unit adjusts the initial position and then moves the regulating unit in a direction away from the clamp unit to move the sheet stack to a position where the protrusion amount is based on information about the sheet stack. (Item 6) The sheet processing apparatus according to any one of items 2 to 4, wherein the transport unit transports the sheet stack so as to press it against the regulating unit after adjusting the initial position. (Item 7) The sheet processing apparatus according to item 5, wherein the transport unit transports the sheet stack so as to press it against the regulating unit after adjusting the initial position.(Item 8) An image forming system comprising: an image forming device having an image forming unit that forms an image on a sheet; and a sheet processing device according to any one of items 1 to 7 that is connected to the image forming device and receives a sheet on which an image has been formed by the image forming unit.

[0158] The sheet processing apparatus and image forming system according to the present disclosure are suitable for a sheet processing apparatus that performs square spine processing on a sheet stack, and an image forming system that includes the sheet processing apparatus.

[0159] The present disclosure is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the present disclosure. Therefore, the following claims are appended to apprise the public of the scope of the present disclosure.

[0160] This application claims priority based on Japanese Patent Application No. 2024-106309 filed on July 1, 2024, Japanese Patent Application No. 2024-106312 filed on July 1, 2024, Japanese Patent Application No. 2024-106313 filed on July 1, 2024, and Japanese Patent Application No. 2025-101664 filed on June 17, 2025, the entire contents of which are incorporated herein by reference.

[0161] 3: Image forming unit 100: Saddle path roller (second conveying means) 104: Saddle stitching processing unit 112: Center folding processing unit 118: Saddle third roller pair (conveying means, first conveying means) 120: Lower clamp unit (clamp) 121: Upper clamp unit (clamp) 123: Pressing roller 500: Skew correction unit 501: Contact member 510: Movement mechanism 1000: Image forming system A: Image forming apparatus B: Sheet processing apparatus C2: Square spine processing unit

Claims

1. A sheet processing device comprising: a conveying unit that conveys a folded sheet stack bound at the crease; a clamping unit that clamps the sheet stack conveyed by the conveying unit at a clamping position; and a pressing unit that presses the sheet stack, and performs a square spine processing on the spine of the sheet stack by moving the pressing unit along the crease of the sheet stack clamped by the clamping unit; a regulating unit that restricts the amount of protrusion of the sheet stack from the clamping position by hitting the spine of the sheet stack when moving from an initial position to a regulating position; and an adjusting unit that pre-adjusts the initial position of the regulating unit relative to the clamping position each time the square spine processing is performed.

2. The sheet processing apparatus according to claim 1, wherein the regulating unit is movable in a direction approaching the clamp unit and a direction away from the clamp unit, and the adjustment unit moves the regulating unit in a direction approaching the clamp unit to adjust the initial position, and then moves the regulating unit in a direction away from the clamp to move it to the regulating position based on information about the sheet stack transported by the transport unit.

3. The sheet processing apparatus according to claim 2, wherein the adjustment section abuts the regulating section against the clamp section when adjusting the initial position.

4. A sheet processing apparatus as described in claim 3, wherein the clamping section has a fixed first clamp and a second clamp that is movable in a direction approaching the first clamp and a direction away from the first clamp and clamps the sheet stack together with the first clamp, and the adjustment section abuts the regulating section against the first clamp when adjusting the initial position.

5. A sheet processing apparatus as described in claim 1, wherein the adjustment unit adjusts the initial position and then moves the regulating unit away from the clamp unit to move the sheet stack to a position where the protrusion amount is based on information about the sheet stack.

6. The sheet processing apparatus according to claim 2, wherein the transport section transports the sheet stack so as to press the sheet stack against the regulating section after adjusting the initial position.

7. An image forming system comprising: an image forming device having an image forming unit that forms an image on a sheet; and a sheet processing device according to claim 1 that is connected to the image forming device and that receives a sheet on which an image has been formed by the image forming unit.

Images