Sheet processing device and image formation system

Abstract

A corner spine processing part C2 performs corner spine processing for pressing a spine of a sheet bundle, which is clamped by an upper clamp unit 121 and a lower clamp unit 120, using a pressing roller 123 so that the spine of the sheet bundle protrudes to the downstream side with respect to the upper clamp unit 121 and the lower clamp unit 120. In a state in which the upper clamp unit 121 and the lower clamp unit 120 have unclamped the sheet bundle subjected to the corner spine processing by the corner spine processing part C2, a saddle control part is capable of executing a mode in which the sheet bundle subjected to the corner spine processing is conveyed to the downstream side in the conveyance direction by a saddle third roller pair 118, and the sheet bundle is subjected to the corner spine processing again by the corner spine processing part C2.

Description

Sheet processing apparatus and image forming system

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

[0002] As a sheet processing device, a configuration has been proposed in which a folded sheet stack is clamped by a pair of clamping units, and a roller moves and presses the spine of the sheet stack that protrudes beyond the clamping units, thereby cornering the spine of the sheet stack (hereinafter referred to as corner spine processing) (Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2001-260564

[0004] In the configuration described in Patent Document 1, the distance between the stop plate and the clamping unit (the amount by which the spine of the sheet bundle protrudes from the clamping unit) is adjusted according to the bulk (thickness) of the sheet bundle, which is based on the number and material of sheets included in the sheet bundle. In this case, it is believed that the amount by which the spine of the sheet bundle protrudes from the clamping unit increases as the number of sheets included in the sheet bundle increases, thereby enabling better square spine processing of the sheet bundle. Note that in the above configuration, adjusting the amount by which the spine of the sheet bundle protrudes from the clamping unit affects the strength of the square spine processing (the finished product after square spine processing). Therefore, it is also conceivable to adjust the amount by which the spine of the sheet bundle protrudes based on user operation.

[0005] Here, the more the spine of the sheet stack protrudes from the clamping unit due to adjustments based on sheet stack information or user operation, the more likely it is that the spine of the sheet stack will be damaged when the pressure roller moves and begins to press against the spine of the sheet stack, and the user may not be able to obtain the desired end product.

[0006] An object of the present invention is to provide a configuration that can prevent the spine of a sheet bundle from being damaged when square spine processing is performed on the sheet bundle.

[0007] One aspect of the present invention is a sheet processing apparatus including: a conveying section that conveys a sheet bundle that has been saddle-stitched and center-folded so that the spine of the sheet bundle is located downstream of the fore-edge in the conveying direction; a pair of clamping units that move relative to the sheet bundle conveyed by the conveying section to clamp and release the clamping of the sheet bundle; a square spine processing section that performs square spine processing by pressing the spine of the sheet bundle clamped between the pair of clamping units toward the pair of clamping units with the pressure roller so that the spine of the sheet bundle protrudes downstream from the pair of clamping units in the conveying direction of the sheet bundle by the conveying section; and a control section that is capable of executing a mode in which, when the clamping by the pair of clamping units is released from the sheet bundle that has been square spine processed by the square spine processing section, the sheet bundle that has been square spine processed is conveyed downstream in the conveying direction by the conveying section and the square spine processing is again performed by the square spine processing section.

[0008] One aspect of the present invention is an image forming unit that forms an image on a sheet; a saddle stitching processing unit that performs a saddle stitching process on a sheet bundle including sheets on which an image has been formed by the image forming unit; a center folding processing unit that performs a center folding process on the sheet bundle that has been saddle stitched by the saddle stitching processing unit; a conveying section that conveys the sheet bundle that has been saddle stitched and center folded so that the spine of the sheet bundle is located downstream of the fore edge in the conveying direction; a pair of clamping units that move relative to the sheet bundle conveyed by the conveying section to clamp and release the sheet bundle; and a control unit that is capable of executing a mode in which, when the clamping by the pair of clamping units is released from the clamping of the sheet bundle that has been subjected to the square spine processing by the square spine processing processor, the sheet bundle that has been subjected to the square spine processing by the square spine processing processor is transported downstream in the transport direction by the conveying unit, and the square spine processing is again performed by the square spine processing processor.

[0009] According to the present invention, it is possible to prevent the spine of a sheet bundle from being damaged when square spine processing is performed on the sheet bundle.

[0010] 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 pressure roller unit according to an embodiment; a cross-sectional view of a pressure roller 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 showing a pressure roller unit and a part of a drive unit according to an embodiment; a perspective view of the vicinity of the square spine processing unit according to an embodiment; a cross-sectional view of a pressure roller unit and a clamping unit according to an embodiment; a schematic view showing a state in which conveyance of a sheet bundle is stopped in a square spine processing operation according to an embodiment; a schematic view showing a state in which a sheet bundle is clamped in a square spine processing operation according to an embodiment; a schematic view showing a state in which square spine processing is being performed on a sheet bundle in a square spine processing operation according to an embodiment; a schematic view showing a state in which the clamp of a sheet bundle is released in a square spine processing operation according to an embodiment. 1 is a schematic diagram showing a state in which the conveyance of a sheet bundle is stopped by a clamping unit in a second square spine processing operation in an embodiment. 2 is a schematic diagram showing a state in which the sheet bundle is clamped in a second square spine processing operation in an embodiment. 3 is a schematic diagram showing a state in which the second square spine processing is being performed on the sheet bundle in a second square spine processing operation in an embodiment. 4 is a schematic diagram showing a state in which the clamp of the sheet bundle is released in a second square spine processing operation in an embodiment. 5 is a diagram showing a mode selection screen according to an embodiment. 6 is a diagram showing a warning screen according to an embodiment. 7 is a diagram showing a cancellation screen according to an embodiment. 8 is a flowchart showing an example of control of square spine processing according to an embodiment.

[0011] The embodiment will be described with reference to Figures 1 to 16. First, the schematic configuration of an image forming system according to the embodiment will be described with reference to Figure 1.

[0012] [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 for 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 a copier, printer, printing machine, facsimile, or multifunction device having multiple 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 ).

[0013] 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.

[0014] 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 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 according to a size specified by the control unit 310 ( FIG. 3 ) of the image forming apparatus A. A sheet S supplied from one of the multiple cassettes 2a, 2b, and 2c is further conveyed downstream by conveyance rollers 7. The leading edge of the sheet S conveyed by the conveyance rollers 7 is aligned by a pair of registration rollers 8, and skew is corrected. The sheet S, whose leading edge has been aligned by the pair of registration rollers 8, is then fed to the downstream image forming unit 3 at a predetermined timing.

[0015] 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.

[0016] 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.

[0017] The image forming unit 3 shown in FIG. 1 includes a photoconductor 9 formed in a drum or belt shape, an exposure device 10 that exposes the photoconductor 9 to light, a development device 11 that develops an electrostatic latent image on the photoconductor 9 using 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 to light 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] [Overall Configuration of Sheet Processing Apparatus] Next, the overall configuration of sheet processing apparatus B, which performs processes such as stapling 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, a path refers to the entire route along which sheets are conveyed by conveying guides, conveying rollers, etc.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] [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 outlet 16 of the image forming device A and the receiving section 26 of the sheet processing device B from the installation surface are approximately the same, and the discharge outlet 16 and the receiving section 26 are connected.

[0027] [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.

[0028] 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.

[0029] 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.

[0030] [Path branching section] 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.

[0031] [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).

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] [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. After being center-folded and folded, the sheet guided to the saddle section B2 by the saddle path 32 passes through a substantially horizontal post-fold path guide 114, a second roller post-path guide 116, a clamp pre-guide 119, and a saddle discharge guide 124, and is discharged to a saddle discharge unit 131. In this embodiment, the saddle discharge guide 124 as a discharge guide section is used as an auxiliary guide for properly stacking the sheet in the saddle discharge unit 131.

[0038] [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.

[0039] 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.

[0040] 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.

[0041] 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 described in the claims. 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 described in the claims.

[0042] [Saddle Unit] The saddle unit B2 will be described with reference to FIGS. 2 and 4. The saddle unit B2 includes a center-folding mechanism C1 and a square spine processing unit C2. The center-folding mechanism C1 collates and stacks sheets fed from the conveying path 28 into 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 as the second conveying unit, described later), and folds the sheet bundle at the stitched position (hereinafter also referred to as "magazine finishing"). The square spine processing unit 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 saddle third roller pair 118 as the first conveying unit, described later). The square spine processing unit C2 creases the spine of the center-folded sheet bundle. A saddle discharge unit 131 is located downstream of the square spine processing unit C2 in the first conveying direction, and stacks the bound sheet bundle. It is also possible to collate and stack one or more sheets, and then perform only center folding, which folds the center of the sheet in the conveying direction, without saddle stitching or square spine processing.

[0043] [Center-Folding Mechanism] The center-folding mechanism C1 has 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, and accumulates sheets into a bundle and performs center-folding and saddle stitching processes. That is, sheets transported from the transport path 28 to the saddle path 32 are transported by saddle path rollers 100 as a second transport section to a collecting section and a saddle stack tray 150 as a second collecting 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 bundle. The sheet bundle 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 unit 104 performs binding processing on the center portion in the conveying direction (middle portion in the second conveying direction) of the sheet bundle positioned by the leading edge regulating stopper 109. The center folding processing unit 112 has a pushing plate 112a and a pair of folding rollers 113, and folds the sheet bundle by conveying the sheet bundle with the pair of folding rollers 113 while pushing the vicinity of the position where binding processing was performed by the saddle stitching processing unit 104 (the center portion in the conveying direction of the sheet bundle where binding processing was performed) with the pushing plate 112a, and conveys the sheet bundle so that the spine of the sheet bundle is on the downstream side in the conveying direction.

[0044] The saddle stitching unit 104 is a mechanism that performs binding by moving the head unit and the anvil unit along the center line of the sheets while sandwiching the sheet stack between them. 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.

[0045] [Square Spine Processing Section] The square spine processing section C2 performs square spine processing on a sheet bundle by center-folding the fold lines of the sheet bundle into a square spine shape, and includes a clamp mechanism C5 and a pressure roller unit 134. That is, the square spine processing section C2 includes a pair of clamping units: a lower clamp unit 120 and an upper clamp unit 121, and a pressure roller 123. The lower clamp unit 120 and the upper clamp unit 121 clamp and release the clamping of the sheet bundle by moving relatively along the thickness direction of the sheet bundle conveyed by a third saddle roller pair 118 (described later). The pressure roller 123 presses the spine of the sheet bundle by moving along the width direction of the sheet bundle (the direction perpendicular to the conveying direction of the sheet bundle, i.e., the front-to-back direction in FIGS. 2 and 4 ). The square spine processing unit C2 performs square spine processing to corner the spine of the sheet bundle 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. Note that the above-mentioned "corner" includes a curved surface, and refers to the boundary between the cover and spine of the sheet bundle, and the boundary between the spine and back cover.

[0046] Specifically, the square spine processing unit C2 clamps a portion of the sheet bundle, which has been center-folded by the center-folding mechanism C1, from both sides in the vertical direction (thickness direction of the sheet bundle) while projecting the spine downstream in the first transport direction. The pressure roller 123 presses the spine of the sheet bundle, which is clamped between the lower clamp unit 120 and the upper clamp unit 121, along the width direction of the sheet bundle, which is perpendicular to the transport direction and thickness direction of the sheet bundle. In this way, the square spine processing unit C2 performs square spine processing, which forms a corner on the spine of the sheet bundle. Square spine processing is a process in which the pressure roller 123 flattens the spine of the sheet bundle shown in FIGS. 11A and 11B (described later), forming two creases on the spine of the sheet bundle and forming two corners on the spine of the sheet bundle, as shown in FIGS. 11C and 11D. The two corners on the spine of the sheet bundle are formed at positions in the thickness direction of the sheet bundle where staples inserted during binding by the saddle stitching unit 104 will be sandwiched. The two corners formed on the spine of the sheet stack are positioned to sandwich the fold formed during the center folding process by the center folding unit 112 .

[0047] 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.

[0048] 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 by disposing the saddle path 32 and the saddle section B2 in a substantially vertical direction, it is possible to slim down the horizontal width of the device.

[0049] A saddle discharge unit 131 is disposed downstream of the saddle section B2 in the sheet bundle conveyance direction, and stores the folded sheet bundle in a magazine shape. The illustrated saddle discharge unit 131 is disposed vertically below the first tray 49. This is because the device specifications assume that the first tray 49 will be used more frequently than the saddle discharge unit 131, and the first tray 49 is set at a height position that makes it easy to remove sheets from the tray.

[0050] [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.

[0051] 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.

[0052] The saddle inlet rollers 101 further convey the sheets delivered by the saddle path rollers 100 from the saddle path 32 downward. 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 pressing guide 103 presses the trailing edges of the sheets stacked on the saddle stack tray 150. The saddle stitching processing unit 104 performs a binding process on the center of the sheet stack accumulated on the saddle stack tray 150 in the conveying direction. The pull-in separation roller 105 assists in the conveyance of the sheets conveyed to the saddle stack tray 150 and is a roller that pulls the sheets toward the leading edge regulating stopper 109. The pull-in separation roller 105 is arranged so as to be able to abut against and separate from the opposing roller 105a.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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).

[0061] [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 of the fore edge in the conveying direction, and then transfers the sheet bundle to the post-folding path guide 114. The post-folding path guide 114 is disposed downstream of the folding roller pair 113 in the conveying direction, 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.

[0062] 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.

[0063] The post-fold path guide 114 guides the conveyance of the sheet bundle and leads it to a second saddle roller pair 115 located downstream in the conveyance direction. A second saddle roller conveyance direction 115c, which is a direction along a perpendicular to a line passing through the rotation centers of the rollers of the second saddle roller pair 115, is disposed along a direction that descends vertically downward as it moves downstream in the conveyance direction. The second saddle roller pair 115 is driven by the center-folding control unit 344 to convey the sheet bundle.

[0064] The sheet bundle conveyed by the saddle second roller pair 115 is delivered to and guided by a second roller post-path guide 116, which is disposed downstream in the conveyance direction and parallel to the saddle second roller conveyance direction 115c (FIG. 2). The second roller post-path guide 116 also has a second roller post-path upper guide 116a that guides the top surface of the sheet bundle, and a second roller post-path lower guide 116b that guides the bottom surface of the sheet bundle. A saddle conveyance sensor 117 is disposed vertically above the guide surface of the second roller post-path upper guide 116a, between the sheet bundle receiving opening and the sheet bundle discharge opening. The saddle conveyance sensor 117 detects the position of the leading edge of the sheet bundle.

[0065] The second roller post-path guide 116 guides the conveyance of the sheet and leads it to a saddle third roller pair 118 located downstream in the conveyance direction. A saddle third roller conveyance direction 118c (FIG. 2), which is a direction along a perpendicular line (a second virtual line β2, FIG. 4, which will be described next) to a line passing through the rotation centers of the rollers of the saddle third roller pair 118, is disposed along a direction that descends vertically downward as it approaches the downstream in the conveyance direction.

[0066] The saddle third roller pair 118, which serves as a conveying unit and a conveying roller pair, is driven by the center folding control unit 344 to sandwich and convey the saddle-stitched and center-folded sheet bundle so that the spine of the sheet bundle is located downstream of the fore-edge end 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 is at the leading edge. If the direction in which the sheet bundle is conveyed by the saddle third roller pair 118, which also serves as the first conveying unit, is the first conveying direction (saddle third roller conveying direction 118c), the saddle path roller 100, which serves as a second conveying unit and conveys sheets to the center folding mechanism C1, is located upstream of the saddle third roller pair 118 in the first conveying direction. The saddle path roller 100 conveys the sheets in a second conveying direction, which is different from the first conveying direction, upstream of the saddle third roller pair 118 in the first conveying direction. Hereinafter, the upstream and downstream sides of the first conveying direction (saddle third roller conveying direction 118c), which is the direction in which the sheet stack is conveyed by the saddle third roller pair 118, may be simply referred to as the "upstream side" and the "downstream side".

[0067] The folding roller pair 113, the second saddle roller pair 115, and the third saddle roller pair 118 are driven by the same motor, and the center folding control unit 344 controls the driving of each of these roller pairs by controlling this motor. The third saddle roller pair 118 holds the sheet bundle center-folded by the center folding processing unit 112 and transports it toward the square spine processing unit C2, and is located immediately upstream of the square spine processing unit C2.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] [Details of the Square Spine Processing Section] The square spine processing section C2 will be described with reference to Figs. 2 and 4, as well as Figs. 5 to 10. As described above, the square spine processing section C2 includes a pair of clamping units, namely, a lower clamp unit 120 and an upper clamp unit 121, and a pressure roller 123. As shown in Fig. 5, 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.

[0073] The clamp front guide 119 includes a clamp front upper guide portion 119a as a first guide portion that guides the top surface of the sheet stack, and a clamp front lower guide portion 119b as a second guide portion that guides the bottom surface of the sheet stack. The clamp front upper guide portion 119a and the clamp front lower 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 center-folding 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 upper guide portion 119a and the clamp front lower 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). Note that at least one of the clamp front upper guide portion 119a and the clamp front lower guide portion 119b may be omitted.

[0074] 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.

[0075] In this embodiment, the upper clamp unit 121 serving as the first clamp unit is movable, and the lower clamp unit 120 serving as the second clamp unit is fixed. That is, the upper clamp unit 121 moves in a direction approaching the lower clamp unit 120 to clamp the sheet bundle. 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 bundle 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 FIGS. 5 and 11A-D).

[0076] 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 upper guide portion 119a and the clamp front lower 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 lower guide portion 119b is fixed to the lower clamp unit 120, and the clamp front upper guide portion 119a is fixed to the upper clamp unit 121. In this embodiment, the clamp front upper guide portion 119a moves together with the upper clamp unit 121 in a substantially vertical direction (the thickness direction of the sheet bundle).

[0077] [Pressure Roller Unit] Next, the internal configuration of the pressure roller unit 134 will be described using Figures 5 to 10. The pressure roller unit 134 has a unit frame 147, roller pressure units 138a and 138b, pressure springs 145a and 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 Figures 5 and 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.

[0078] 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.

[0079] 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.

[0080] 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 lower plate 147d and extending upward 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.

[0081] 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.

[0082] 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. 5). 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.

[0083] 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.

[0084] When the leading edge of the sheet bundle conveyed by the saddle third roller pair 118 is detected by the saddle conveyance sensor 117, the conveyance distance is counted by the square spine processing control unit 345, and the sheet bundle is stopped after being conveyed a predetermined distance. Specifically, as shown in FIG. 11A (described later), the center-folded sheet bundle is stopped in a state where the spine of the sheet bundle protrudes downstream in the conveyance direction beyond the upper clamp unit 121 and the lower clamp unit 120. In this embodiment, in the square spine processing, the amount of protrusion of the spine of the sheet bundle from the upper clamp unit 121 and the lower clamp unit 120 is adjusted by controlling the conveyance distance of the sheet bundle by the saddle third roller pair 118.

[0085] [Upper Clamp Unit and Lower Clamp Unit] The upper clamp unit 121 moves from a receiving position (first position) where it receives a sheet bundle to a clamp holding position (second position) where it holds the sheet bundle, thereby pressurizing the sheet bundle between itself and the lower clamp unit 120 and holding the sheet bundle with the upper clamp surface 142 and the lower clamp surface 143. At this time, as shown in Fig. 11B described later, the leading edge of the sheet bundle protrudes by a predetermined protrusion amount P1 from end surfaces 120c and 121b on the downstream side in the conveying direction of the lower clamp unit 120 and the upper clamp unit 121 after clamp holding.

[0086] The upper clamp unit 121 is operated by driving a clamp drive motor 132 (FIGS. 7A and 7B) by the square spine processing control unit 345. 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. A plurality of 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.

[0087] [Square spine processing section] As shown in Figure 11C described later, the square spine processing section C2 performs square spine processing on a sheet bundle held between the lower clamp unit 120 and the upper clamp unit 121 in a state where it protrudes a predetermined protrusion amount P1 from the end faces 120c, 121b by pressing the spine of the sheet bundle while scanning in the width direction of the sheet bundle with a pressure roller 123 located downstream in the conveying direction.

[0088] During square spine processing, the pressure roller 123 is moved by operating the drive motor 135 ( FIG. 7B ) via the square spine processing control unit 345. As shown in FIG. 8 , the pressure roller 123 is connected to a drive belt 137 arranged in the width direction of the sheet bundle, and is movable in the width direction of the sheet bundle along a guide rail 120b (see FIG. 9 ). The drive belt 137 is rotated by power transmitted from the drive motor 135 via a drive train 136 ( FIG. 7B ) consisting of a gear train. This allows the pressure roller 123 to scan the sheet bundle in the width direction. The home positions of the pressure roller 123 are located on the front and rear sides of the sheet processing device B. That is, the pressure roller 123 can be moved from the rear side to the front side for the first sheet bundle to perform square spine processing, and then the pressure roller 123 can be moved from the front side to the rear side for the second sheet bundle to perform square spine processing. A sensor (not shown) is provided at each home position of the pressure roller 123, making it possible to detect the position of the pressure roller 123. However, the 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 way, when the home position is provided on either side, for example, the pressure roller 123 may be moved from the rear side to the front side for the first sheet stack to perform the square spine processing, and then the pressure roller 123 may be returned from the front side to the rear side, and the pressure roller 123 may be moved from the rear side to the front side for the second sheet stack to perform the square spine processing, etc.

[0089] 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.

[0090] 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.

[0091] 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. 11D, 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.

[0092] [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 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 down vertically from the first fulcrum 124b.

[0093] 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.

[0094] The guide surface 124d is located below a line extending from 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.

[0095] 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.

[0096] As the sheet bundle continues to be conveyed by the saddle third roller pair 118, it is delivered to a saddle discharge unit 131 that is disposed downstream of the pressure roller unit 134 in the first conveying 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.

[0097] 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.

[0098] 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.

[0099] The sheet bundle delivered to the saddle discharge unit 131 is guided and transported by the saddle discharge upstream belt 127 and the saddle discharge downstream belt 129, and then stacked. 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.

[0100] 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. The stopping position of this preceding sheet bundle 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 a position that makes contact with the upper surface of the preceding sheet bundle when the succeeding sheet bundle 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).

[0101] 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, so that the succeeding sheet bundle is stably stacked in a tiled manner without causing problems such as getting caught on the preceding sheet bundle, curling, or being pushed out. In other words, by appropriately changing the above-mentioned transport amount according to the size of the sheet bundle, the succeeding sheet bundle can be stably stacked on top of the preceding sheet bundle.

[0102] 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.

[0103] 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.

[0104] [Control of Square Spine Processing] Next, the control of square spine processing in this embodiment will be described with reference to Figures 11 to 16. As described above, the square spine processing unit C2 performs square spine processing to square the spine of a sheet bundle that has been saddle-stitched and center-folded. In this embodiment, in addition to the first mode, which is normal square spine processing, a second mode can be performed to perform stronger square spine processing on the sheet bundle. 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.

[0105] [First Mode] First, the first mode will be described with reference to FIGS. 11A to 11D. In the first mode, the pressure roller 123 is pressed against the spine of the sheet bundle Sb only once. The center-folding control unit 344 is triggered by the saddle transport sensor 117 detecting the leading edge of the sheet bundle Sb, and transports the center-folded sheet bundle Sb between the upper clamp unit 121 and the lower clamp unit 120, which are spaced apart. Then, as shown in FIG. 11A, the center-folding control unit 344 stops transport of the sheet bundle Sb in a state in which the spine Ssp of the sheet bundle Sb protrudes further downstream in the first transport direction than the downstream end faces 121b and 120c of the upper clamp unit 121 and the lower clamp unit 120 in the first transport direction.

[0106] 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. 11B, the sheet bundle Sb is clamped between 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.

[0107] 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. 11C, 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. 11D, 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. In the first mode, the square spine processing is completed up to this point, and the above-described discharge operation of the sheet bundle Sb is performed.

[0108] [Second Mode] Next, the second mode will be described using FIGS. 12A to 12D in addition to FIGS. 11A to 11D. In the second mode, in addition to the first mode described above, a square spine treatment is further performed on the spine Ssp of the sheet bundle Sb. That is, in the second mode, the sheet bundle Sb that has been subjected to the square spine treatment is transported downstream in the first transport direction by the third saddle roller pair 118, and the square spine treatment is performed again. A specific description will be given. In the second mode, after the square spine treatment shown in FIGS. 11A to 11D is performed, a second square spine treatment is performed as shown in FIGS. 12A to 12D.

[0109] 11D, after the sheet bundle Sb has been subjected to the square spine processing once, the upper clamp unit 121 is raised to release the sheet bundle Sb from the clamping by the upper clamp unit 121 and the lower clamp unit 120, and the upper clamp unit 121 is moved to the standby position. During the first square spine processing, the pressure roller 123 moves from the front side to the rear side, and when the first square spine processing is completed, the pressure roller 123 is located at the home position on the rear side.

[0110] Next, the center-folding control unit 344 drives the third saddle roller pair 118 to transport the sheet bundle Sb further downstream as shown in FIG. 12A , and stops the transport of the sheet bundle Sb when it has been transported a predetermined distance. 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. 12B , the sheet bundle Sb is clamped between 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 a distance P2 beyond the downstream end faces 121b and 120c of the upper clamp unit 121 and the lower clamp unit 120 in the first transport direction.

[0111] At this time, the protrusion amount P2 of the spine Ssp of the sheet bundle Sb from the end faces 121b, 120c of the upper clamp unit 121 and the lower clamp unit 120 is set to be equal to or less than the protrusion amount P1 during the first square spine processing. That is, in the first square spine processing, the protrusion amount of the spine Ssp of the sheet bundle Sb held between the upper clamp unit 121 and the lower clamp unit 120 from the end faces 121b, 120c of the upper clamp unit 121 and the lower clamp unit 120 before being pressed by the pressing roller 123 is set to be the first protrusion amount P1. Also, in the second square spine processing, the protrusion amount of the spine Ssp of the sheet bundle Sb held between the upper clamp unit 121 and the lower clamp unit 120 from the end faces 121b, 120c of the upper clamp unit 121 and the lower clamp unit 120 before being pressed by the pressing roller 123 is set to be the second protrusion amount P2. In this case, the second protrusion amount P2 is the same as the first protrusion amount P1 or is smaller than the first protrusion amount P1, that is, is equal to or smaller than the first protrusion amount P1 (P2≦P1).

[0112] In this embodiment, the protrusion amounts P1 and P2 are set by controlling the conveyance stop position of the sheet bundle Sb by driving the third saddle roller pair 118 using the center folding control unit 344. That is, as described above, the protrusion amounts P1 and P2 are adjusted by controlling the conveyance amount of the sheet bundle by the third saddle roller pair 118. However, a stopper that abuts against the spine of the sheet bundle may be disposed downstream of the upper clamp unit 121 and the lower clamp unit 120, and the protrusion amounts of the spine of the sheet bundle may be set to P1 and P2 by changing the position of this stopper. Note that if P1 and P2 are the same, the position of the stopper may not be changed. In either case, the stopper is movable between a position where it abuts against the sheet bundle and a position retracted from this position.

[0113] 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. 12C, the pressure roller 123 moves from the rear side to the front side 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 a second square spine processing. That is, in the first square spine processing, the pressure roller 123 moves from the front side to the rear side, and at the start of the second square spine processing, the pressure roller 123 has already moved to the rear side. Therefore, in the second square spine processing, the pressure roller 123 moves from the rear side to the front side. Note that if the pressure roller 123 has moved from the rear side to the front side in the first square spine processing, the pressure roller 123 will move from the front side to the rear side in the second square spine processing. In addition, if the home position is only on either the front side or the rear side, the pressure roller 123 returns to the home position each time the square spine processing is completed, so the pressure roller 123 is moved from the same position for the first and second times. In other words, the pressure roller 123 may be configured to move back and forth during the first square spine processing, and to move back and forth during the second square spine processing as well.

[0114] This embodiment has a mode in which the square spine processing can be performed multiple times (at least two times). This allows for a smaller protrusion of the spine Ssp of the sheet bundle Sb in one square spine processing. Furthermore, since the spine Ssp of the sheet bundle Sb that has undergone square spine processing once is protruded from the upper clamp unit 121 and the lower clamp unit 120 before square spine processing is performed again, it allows for stronger square spine processing. Then, as shown in FIG. 12D , 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 and release the clamping of the sheet bundle Sb. That is, after the second square spine processing is performed, the upper clamp unit 121 is raised, separated from the sheet bundle Sb, and moved to the standby position. Then, the discharge processing is performed as described above. In the second mode of this embodiment, square spine processing is performed twice, but square spine processing may be performed three or more times. That is, the first mode is a mode in which the square spine processing is performed only once for one sheet bundle, while the second mode is a mode in which the square spine processing is performed multiple times for one sheet bundle, and the number of times the square spine processing is performed can be set appropriately as long as it is multiple. Also, the number of times the square spine processing is performed may be selectable.

[0115] In the above-described square spine processing, increasing the amount by which the spine of the sheet bundle protrudes from the end faces 121b, 120c of the upper clamp unit 121 and the lower clamp unit 120 increases the pressing force of the pressure roller 123 against the spine of the sheet bundle, resulting in a stronger square spine processing shape. However, if the spine of the sheet bundle protrudes too much from the end faces 121b, 120c of the upper clamp unit 121 and the lower clamp unit 120, when the pressure roller 123 scans along the lower clamp unit 120 and the upper clamp unit 121, a large impact is applied when the pressure roller 123 rides over the end (protruding portion) of the spine of the sheet bundle, causing damage (scratches, wrinkles, etc.) to the spine of the sheet bundle.

[0116] In the second mode described above, by performing the square spine processing twice rather than increasing the protrusion amount of the spine of the sheet bundle at one time, the protrusion amount of the spine of the sheet bundle can be reduced each time, thereby suppressing damage when the pressure roller 123 runs up on the spine of the sheet bundle. In other words, by performing the first square spine processing and setting the protrusion amount of the spine of the sheet bundle from the end faces 121b, 120c of the upper clamp unit 121 and the lower clamp unit 120 to P2 (P2≦P1) when performing the second square spine processing, it is possible to reduce the impact when the pressure roller 123 runs up on the end (protrusion) of the spine of the sheet bundle.

[0117] Furthermore, the amount of protrusion of the spine of the sheet stack from the end surfaces 121b, 120c of the upper clamp unit 121 and the lower clamp unit 120 can be substantially greater than when square spine processing is performed only once. That is, in the second mode, the spine of the sheet stack is crushed once in the first square spine processing, and the second square spine processing causes the sheet stack to protrude further from this state. Therefore, the combined amount of protrusions is greater than when square spine processing is performed only once. Therefore, by performing the second mode, it is possible to form a stronger square spine processing shape.

[0118] As described above, in this embodiment, by executing the second mode, damage (scratches and wrinkles) to the spine of the sheet stack can be suppressed. Furthermore, the opening of the sheet stack after folding can be suppressed. Furthermore, the second mode requires additional clamping of the sheet stack and a second square spine processing, which increases the processing time compared to the first mode. Therefore, it is preferable to provide a high-productivity mode and a high-quality mode, which can be selected by an operator such as a user. For example, when the high-productivity mode is selected, only the first mode can be executed when square spine processing is performed. When the high-quality mode is selected, the first mode and the second mode can be selectively executed when square spine processing is performed. The selection between the first mode and the second mode is described below.

[0119] [Mode Selection] The selection between the first mode and the second mode will be described with reference to Figures 13 to 15. Figure 13 shows a UI screen for mode selection that is displayed on a display unit, such as an LCD screen, of the operation unit 302 of the image forming system 1000. In this embodiment, the display unit is a touch panel that can be operated by hand, and the mode selection screen is displayed on the touch panel of the operation unit 302 and can be operated by touch by an operator such as a user or a service technician.

[0120] When selecting a mode, first select "ON" or "OFF" for "Square back processing." If ON is selected, the mode in which square back processing is performed is selected, and at this point, the first mode or the second mode can be performed. Next, select "ON" or "OFF" for "Strong mode." If ON is selected, the second mode is performed, and if OFF is selected, the first mode is selected. Then, if "OK" is selected, the mode is confirmed. Figure 13 shows the screen when square back processing in the strong mode (second mode) is selected.

[0121] If the type of sheet is incompatible with the second mode, the "strong mode" may be made unselectable. For example, the selection screen for the "strong mode" may be hidden or grayed out. In addition, the type of sheet bundle incompatible with the second mode may be, for example, a sheet bundle with a basis weight of a predetermined value or less (80 g / m ２ The type of sheet bundle that corresponds to the second mode is a thin sheet bundle that is made up of five sheets with a basis weight of a predetermined value or less (80 g / m or less). ２ The sheet bundle is a thick one, consisting of 25 sheets even if the number of sheets is less than 100 (see below). The sheet basis weight is set in advance for each of cassettes 2a to 2d (FIG. 1) by an operator such as a user via operation unit 302. Saddle control unit 350 acquires information on the basis weight of the sheets in each cassette from image forming apparatus A via communication unit 341.

[0122] If the "strong mode" is not displayed or grayed out for sheets that are not compatible with the second mode, a warning screen as shown in Fig. 14 may be displayed. That is, Fig. 14 shows a warning screen when the "strong mode" is selected for a sheet that is not compatible with the second mode on the screen of Fig. 13. For sheets that are not compatible with the second mode (for example, sheets with a basis weight of 80 g / m), ２ If the second mode is executed for sheets (such as the following sheets), the spine of the sheet bundle may be crushed, which may result in a decrease in the quality of the finished product. For this reason, the second mode is preferably executed when the basis weight of the sheets included in the sheet bundle to be squared is greater than a predetermined value, and if the second mode is selected when the basis weight of the sheets is equal to or less than the predetermined value, a warning message is displayed, thereby improving usability.

[0123] If the operator selects "No" on the screen in Fig. 14, the second mode is forcibly executed, and if the operator selects "Yes," the second mode is canceled. If the second mode is canceled, the square spine processing may be executed in the first mode, or a screen may be displayed again to confirm with the user whether or not to execute the square spine processing.

[0124] On the other hand, if the "strong mode" is not hidden or grayed out for sheets that are not compatible with the second mode, a cancel screen as shown in FIG. 15 may be displayed instead of the warning screen as shown in FIG. 14. FIG. 15 shows a screen that automatically cancels the second mode when the "strong mode" is selected for a sheet that is not compatible with the second mode on the screen as shown in FIG. 13. When the operator presses "OK" on this screen, the second mode is automatically canceled. In this case, the square spine processing may be performed in the first mode, or a screen may be displayed that prompts the user again to confirm whether or not to perform square spine processing.

[0125] 13, when the "strong mode" is selected for a sheet that is not compatible with the second mode, the screen that is displayed may be not only the automatic cancellation screen of FIG. 15 but also a screen that prompts the user to change the sheet type set by the user to a type that is compatible with the second mode. For example, a screen that prompts the user to select a feeding cassette that contains sheets that are compatible with the second mode from among a plurality of feeding cassettes that each contain different types of sheets may be displayed.

[0126] [Control Flow of Square Spine Processing] Next, an example of the control flow for the square spine processing described above will be described with reference to FIG. 16 . The second mode, which performs square spine processing twice, is particularly effective for sheet bundles containing a predetermined number of sheets or more (e.g., 20 or more). If the number of sheets in a sheet bundle is less than the predetermined number, sufficient cornering of the spine of the sheet bundle can be achieved without performing the second mode. Furthermore, performing the second mode when the number of sheets in a sheet bundle is less than the predetermined number may result in a low-quality product, such as excessively crushed corners on the spine of the sheet bundle. Therefore, in the following flow, the second mode is enabled when the number of sheets in the sheet bundle is greater than the predetermined number (X or more). However, if the number of sheets in the sheet bundle is less than the predetermined number, the second mode is canceled and the first mode is executed, even if the second mode is selected, as in the cases described with reference to FIGS. 14 and 15 . The following control is executed by the saddle control unit 350 of the sheet processing apparatus B in response to a command from the control unit 310 of the image forming apparatus A. The saddle control unit 350 acquires information about the sheets, such as the number of sheets included in the sheet bundle and the basis weight of the sheets in each cassette, from the image forming apparatus A via the communication unit 341 .

[0127] First, when control is initiated, as described above, sheets are conveyed to the saddle section B2, and the sheet bundle that has undergone saddle stitching and center folding is conveyed to the square spine processing section C2 by the third saddle roller pair 118 (S1). Next, conveyance of the sheet bundle is stopped at a position where the spine of the sheet bundle protrudes by L1 beyond the downstream end faces (hereinafter referred to as clamp ends) of the upper clamp unit 121 and the lower clamp unit 120 in the conveying direction (S2). In this state, the sheet bundle is clamped by the upper clamp unit 121 and the lower clamp unit 120 (S3). In this state, the amount of protrusion of the spine of the sheet bundle from the clamp ends is P1 (see FIG. 11B). Then, with the sheet bundle clamped, the first square spine processing is performed on the sheet bundle (S4).

[0128] The saddle control unit 350 determines whether the number of sheets in the sheet stack is X or more (S5), and if the number of sheets is less than X (NO in S5), releases the clamping of the sheet stack by the upper clamp unit 121 and the lower clamp unit 120 to execute the first mode even if the second mode is selected (S6), and then discharges the sheet stack that has been subjected to the square spine processing (S7).

[0129] If the number of sheets in the sheet bundle is X or more (YES in S5), the saddle control unit 350 checks whether the second mode is selected (S8). If the second mode is not selected (NO in S8), the saddle control unit 350 releases the clamping of the sheet bundle by the upper clamp unit 121 and the lower clamp unit 120 (S9), and discharges the sheet bundle that has been subjected to the square spine processing (S10).

[0130] If the second mode is selected in S8 (YES in S8), the upper clamp unit 121 and the lower clamp unit 120 release the clamping of the sheet bundle to execute the second mode (S11). Next, the sheet bundle is conveyed by the third saddle roller pair 118 (S12), and conveyance of the sheet bundle is stopped at a position where the spine of the sheet bundle protrudes from the clamp end by L2 (L2≦L1) (S13). In this state, the upper clamp unit 121 and the lower clamp unit 120 clamp the sheet bundle (S14). In this state, the amount of protrusion of the spine of the sheet bundle from the clamp end is P2 (see FIG. 12B). Then, with the sheet bundle clamped, a second square spine processing is performed on the sheet bundle (S15). After the processing, the upper clamp unit 121 and the lower clamp unit 120 release the clamping of the sheet bundle (S16), and the sheet bundle subjected to the square spine processing is discharged (S17).

[0131] Note that the above-mentioned S5 may be the type of sheet described in FIGS. 14 and 15 instead of the number of sheets in the sheet stack. For example, S5 may be set to "the basis weight of the sheet is a predetermined value Y (80 g / m ２ ) exceeds the limit?". In addition, in S5, the second mode may be made executable when both the number of sheets in the sheet bundle and the type of sheets are satisfied.

[0132] Whether or not to execute the second mode may not only be determined by selecting a mode as described above, but may also be executed when the sheet bundle for which the user has set the square spine processing to be executed is a thick bundle. That is, the second mode may be executed according to the number of sheets and basis weight of the sheet bundle set by the user. In such a case, the protrusion amount that may damage the spine when the pressure roller 123 rides over it may be set to a predetermined protrusion amount, and the second mode may be executed when the protrusion amount of the spine Ssp of the sheet bundle Sb from the end surfaces 121b, 120c of the upper clamp unit 121 and the lower clamp unit 120, which is determined according to the thickness (bulk) of the sheet bundle, exceeds the predetermined protrusion amount.

[0133] Alternatively, the user may be allowed to set the amount of spine protrusion (or the strength of the spine square processing) during the square spine processing, and the second mode may be executed when the user's setting exceeds the predetermined protrusion amount. In this case, if the predetermined protrusion amount is such that damage occurs when the pressing roller 123 rides over the sheet, the first protrusion amount may be set to a protrusion amount that is equal to or less than the predetermined protrusion amount and does not cause damage, and the second protrusion amount may be determined so that the sum of the first protrusion amount and the second protrusion amount is the protrusion amount set by the user.

[0134] <Other Embodiments> In the above-described embodiment, square spine processing is performed downstream inside the saddle unit B2 in the sheet processing device B. However, similar square spine processing may be performed in a separate housing connected to the outside. For example, a single unit may be provided that performs only square spine processing without saddle stitching or center folding. In this case, this unit includes the square spine processing unit C2 described above and a conveying unit including a pair of conveying rollers that conveys the sheet bundle that has been saddle stitched and center folded to the square spine processing unit C2.

[0135] 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.

[0136] Furthermore, in the above embodiment, a pair of rollers is used as an example of a conveying unit that conveys a sheet inside the sheet processing device B, but a belt may be used to convey the sheet. Specifically, any of the following may be used: a pair of rollers that sandwich the sheet between a belt, a pair of belts that sandwich the sheet between a belt, or a belt and rollers that sandwich the sheet. The conveying configuration may be changed depending on the position and route of the sheet. For example, a pair of rollers may be used to convey the sheet at one position, and a pair of belts may be used to convey the sheet at another position.

[0137] 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 may also be used. 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 also 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 also 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.

[0138] The disclosure of this embodiment also includes the following configurations: (Configuration 1) A sheet processing apparatus including: a conveying unit that conveys a sheet bundle that has been saddle-stitched and center-folded so that the spine of the sheet bundle is located downstream of the fore-edge in a conveying direction, a pair of clamping units that move relative to the sheet bundle conveyed by the conveying unit to clamp and release the clamping of the sheet bundle, and a square spine processing unit that performs square spine processing by pressing the spine of the sheet bundle clamped between the pair of clamping units with the pressure rollers toward the pair of clamping units in a conveying direction of the sheet bundle by the conveying unit so that the spine of the sheet bundle protrudes downstream from the pair of clamping units in the conveying direction of the sheet bundle by the conveying unit, and a control unit that is capable of executing a mode in which, when the clamping by the pair of clamping units is released from the sheet bundle that has been square spine processed by the square spine processing unit, the sheet bundle that has been square spine processed is conveyed downstream in the conveying direction by the conveying unit, and the square spine processing is again performed by the square spine processing unit. (Configuration 2) The sheet processing apparatus according to Configuration 1, wherein the control unit controls the square spine processing unit and the transport unit so that a protrusion amount of the spine of the sheet bundle sandwiched between the pair of clamping units before being pressed by the pressure roller becomes a first protrusion amount, and controls the square spine processing unit and the transport unit so that a protrusion amount of the spine of the sheet bundle sandwiched between the pair of clamping units before being pressed by the pressure roller becomes a second protrusion amount less than the first protrusion amount when the square spine processing is performed again on the sheet bundle that has been subjected to the square spine processing. (Configuration 3) The sheet processing apparatus according to Configuration 2, wherein the control unit adjusts the protrusion amount by controlling a transport amount of the sheet bundle by the transport unit in the square spine processing. (Configuration 4) The sheet processing apparatus according to any one of Configurations 1 to 3, wherein the control unit is capable of executing a first mode in which the square spine processing is performed only once for one sheet bundle and a second mode in which the square spine processing is performed multiple times for one sheet bundle. (Configuration 5) The sheet processing apparatus according to Configuration 4, wherein the control unit executes the second mode when the number of sheets included in the sheet bundle on which the square spine processing is performed is equal to or greater than a predetermined number.(Configuration 6) The sheet processing apparatus according to Configuration 4, wherein the control unit executes the second mode when the basis weight of a sheet included in the sheet bundle to be subjected to the square spine processing exceeds a predetermined value. (Configuration 7) The sheet processing apparatus according to any one of Configurations 1 to 6, wherein the transport unit is a first transport unit, and further includes: a second transport unit configured to transport sheets in a second transport direction different from the first transport direction upstream of the first transport unit in the first transport direction when a direction in which the sheet bundle is transported by the first transport unit is a first transport direction; a saddle stitching processing unit configured to stitch a middle portion of the sheet bundle made up of a plurality of sheets transported by the second transport unit in the second transport direction; and a center folding processing unit configured to fold the sheet bundle at the position stitched by the saddle stitching processing unit and transport the sheet bundle so that the spine of the sheet bundle is downstream in the first transport direction; and the sheet processing apparatus according to any one of Configurations 1 to 6, wherein the first transport unit receives the sheet bundle transported downstream in the first transport direction from the center folding processing unit and transports the sheet bundle toward the square spine processing unit.(Configuration 8) An image forming unit that forms an image on a sheet; a saddle stitching unit that performs saddle stitching on a sheet bundle including sheets on which an image has been formed by the image forming unit; a center folding unit that performs center folding on the sheet bundle that has been saddle stitched by the saddle stitching unit; a conveying section that conveys the sheet bundle that has been saddle stitched and center folded so that the spine of the sheet bundle is located downstream of the fore edge in the conveying direction; a square spine processing section that has the following features: a pair of clamping units that clamp and release the sheet bundle by moving relative to the sheet bundle conveyed by the conveying section; and a pressure roller that presses the spine of the sheet bundle clamped between the pair of clamping units toward the pair of clamping units, and performs square spine processing by pressing the pressure roller against the spine of the sheet bundle clamped between the pair of clamping units so that the spine of the sheet bundle protrudes downstream from the pair of clamping units in the conveying direction of the sheet bundle by the conveying section. and a control unit capable of executing a mode in which, when the clamping by the pair of clamping units is released from the sheet bundle that has been subjected to the square spine processing by the square spine processing unit, the sheet bundle that has been subjected to the square spine processing is transported downstream in the transport direction by the transport unit, and the square spine processing is again performed by the square spine processing unit.

[0139] The sheet processing apparatus and image forming system according to the present invention are suitable for a sheet processing apparatus that performs square spine processing on a sheet, and an image forming system that includes such a sheet processing apparatus.

[0140] 3: Image forming section 100: Saddle path roller (second conveying section) 104: Saddle stitching processing section (saddle stitching processing unit) 112: Center folding processing section (center folding processing unit) 118: Saddle third roller pair (conveying section, first conveying section) 120: Lower clamp unit (clamping section) 121: Upper clamp unit (clamping section) 123: Pressing roller 1000: Image forming system A: Image forming apparatus B: Sheet processing apparatus C2: Square spine processing section

Claims

1. A sheet processing device comprising: a conveying section that conveys a sheet bundle that has been saddle-stitched and center-folded so that the spine of the sheet bundle is located downstream of the fore-edge in a conveying direction; a pair of clamping units that clamp and release the clamping of the sheet bundle by moving relatively to the sheet bundle conveyed by the conveying section; and a square spine processing section that performs square spine processing by pressing the spine of the sheet bundle clamped between the pair of clamping units with the pressure roller toward the pair of clamping units so that the spine of the sheet bundle protrudes downstream relative to the pair of clamping units in the conveying direction of the sheet bundle by the conveying section; and a control section that is capable of executing a mode in which, when the clamping by the pair of clamping units of the sheet bundle that has been subjected to the square spine processing by the square spine processing section is released, the sheet bundle that has been subjected to the square spine processing is conveyed downstream in the conveying direction by the conveying section, and the square spine processing is performed again by the square spine processing section.

2. The control unit controls the square spine processing unit and the conveying unit so that a protruding amount of the spine of the sheet stack clamped between the pair of clamping units before being pressed by the pressure roller becomes a first protruding amount, and controls the square spine processing unit and the conveying unit so that a protruding amount of the spine of the sheet stack clamped between the pair of clamping units before being pressed by the pressure roller becomes a second protruding amount less than the first protruding amount when the square spine processing is performed again on the sheet stack that has been subjected to the square spine processing.

3. The sheet processing apparatus according to claim 2, wherein the control unit adjusts the protrusion amount by controlling the transport amount of the sheet stack by the transport unit during the square spine processing.

4. The sheet processing apparatus according to claim 1, wherein the control unit is capable of executing a first mode in which the square spine processing is performed only once for one sheet stack, and a second mode in which the square spine processing is performed multiple times for one sheet stack.

5. The sheet processing apparatus according to claim 4, wherein the control section executes the second mode when the number of sheets included in the sheet bundle on which the square spine processing is performed is equal to or greater than a predetermined number.

6. The sheet processing apparatus according to claim 4, wherein the control unit executes the second mode when the basis weight of a sheet included in the sheet bundle on which the square spine processing is performed exceeds a predetermined value.

7. The sheet processing device according to claim 1, further comprising: a first conveying section, the conveying section being a first conveying section, and a second conveying section which, when a direction in which the first conveying section conveys the sheet stack is defined as a first conveying direction, conveys sheets in a second conveying direction different from the first conveying direction upstream of the first conveying section in the first conveying direction; a saddle-stitching processing unit which performs a binding process on a middle portion of the sheet stack consisting of a plurality of sheets conveyed by the second conveying section, in the second conveying direction; and a center-folding processing unit which performs a center-folding process by folding the sheet stack at the position where it has been bound by the saddle-stitching processing unit, and conveying the sheet stack so that its spine is downstream in the first conveying direction; and the first conveying section receives the sheet stack conveyed downstream in the first conveying direction from the center-folding processing unit and conveys it toward the square spine processing section.

8. An image forming unit which forms an image on a sheet; a saddle stitching processing unit which performs saddle stitching on a sheet bundle including a sheet on which an image has been formed by the image forming unit; a center folding processing unit which performs center folding on the sheet bundle which has been saddle stitched by the saddle stitching processing unit; a conveying section which conveys the sheet bundle which has been saddle stitched and center folded so that the spine of the sheet bundle is located downstream of the fore-edge in the conveying direction; a pair of clamping units which clamp and release the clamping of the sheet bundle by moving relative to the sheet bundle conveyed by the conveying section; and a pressure roller which presses the spine of the sheet bundle clamped by the pair of clamping units towards the pair of clamping units, performing a square spine processing in which the pressure roller presses the spine of the sheet bundle clamped by the pair of clamping units so that the spine of the sheet bundle protrudes downstream relative to the pair of clamping units in the conveying direction of the sheet bundle by the conveying section. a control unit capable of executing a mode in which, in a state in which the clamping by the pair of clamping units is released from the sheet bundle on which the square spine processing has been performed by the square spine processing unit, the sheet bundle on which the square spine processing has been performed is transported downstream in the transport direction by the transport unit, and the square spine processing is performed again by the square spine processing unit.

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