Sheet processing device, sheet processing method and image forming system

Abstract

To provide a sheet processing device capable of forming a press saddle-stitched booklet that is easy to open without peeling off a press stitching due to a page turning operation.SOLUTION: A sheet processing device includes: center folding means that performs center folding processing on a sheet bundle made up of a plurality of sheet materials; and press stitching means that performs a press stitching on the sheet bundle subjected to the center folding processing. The press stitching means includes a back part forming processing unit that forms a back part on the sheet bundle subjected to the center folding processing, and a press stitching processing unit that performs the press stitching processing on the sheet bundle subjected to the center folding processing. The back part forming processing unit includes: a folding plate member having protrusions at both end parts in a plate thickness direction on a pushing surface of the sheet bundle; and a folding plate engagement member that engages with the folding plate member via the sheet bundle.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a sheet processing apparatus, a sheet processing method, and an image forming system. [Background technology]

[0002] Sheet processing devices are known that can perform a "binding process" to bind a sheet bundle formed by bundling sheet-like recording media. There are several types of binding processes that can be performed by sheet processing devices. For example, an "end binding process" that binds the ends of the sheet bundle, and a "saddle stitching process" that folds the sheet bundle in half and stitches the sheets near the fold position, etc., are known. Saddle stitching is a binding method that is primarily used when creating books such as booklets.

[0003] In order to provide a saddle-stitched booklet with aligned edges without edge trimming, a saddle-stitching binding device has been disclosed that crimps and binds both sides away from the center fold position, and then performs a square spine fold to form a square spine in the booklet (see, for example, Patent Document 1).

[0004] Furthermore, for the purpose of providing a pressure saddle stitching device, a saddle stitching bookbinding device that pressure binds at a position away from the folding position has been disclosed (see, for example, Patent Document 2).

[0005] Also disclosed is a staple saddle stitching device that folds the spine of a booklet into a square shape, and that has a groove in the stopper plate for the staple to engage with, in order to prevent the staple from shifting from the center of the spine and provide a booklet that looks good (see, for example, Patent Document 3).

[0006] Furthermore, a pressure saddle stitch bookbinding device has been disclosed that performs a center folding process after pressure binding the center of a booklet, with the aim of providing a staple-free bound booklet (see, for example, Patent Document 4). Summary of the Invention [Problem to be solved by the invention]

[0007] Patent Documents 1 to 4 disclose conventional techniques for performing pressure saddle stitching and folding the spine of a booklet. However, when these conventional techniques are used to form a saddle-stitched booklet, there are issues such as the feeling of discomfort in the spread when turning the pages, or the pressure applied to the pressure-bonded part by the page-turning operation causing the pressure-bonded part to peel off. In other words, when pressure binding is used for saddle stitching, the conventional techniques have issues with the quality and binding strength of the finished product (booklet).

[0008] An object of the present invention is to provide a sheet processing apparatus capable of forming a press-stitched saddle-stitched booklet that can be easily opened without the press-stitched binding coming off when the pages are turned over. [Means for solving the problem]

[0009] In order to solve the above problem, one aspect of the present invention is a center folding device that performs a center folding process on a sheet bundle made up of a plurality of sheet materials, a pressure binding device that performs pressure binding on the sheet bundle that has been center folded, The crimp binding means has a spine forming processing section that forms a spine on the sheet bundle that has been subjected to the center folding processing, and a crimp binding processing section that performs the crimp binding processing on the sheet bundle that has been subjected to the center folding processing, and the spine forming processing section has a folding plate member that has protrusions on both ends in the plate thickness direction on the extrusion surface of the sheet bundle, and a folding plate engaging member that engages with the folding plate member via the sheet bundle. [Effects of the Invention]

[0010] According to the present invention, a press-stitched saddle-stitched booklet can be formed that is easy to open and that does not come apart when pages are turned over. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a diagram showing the overall configuration of an image forming system according to a first embodiment. [Figure 2] FIG. 2 is a diagram showing the internal structure of the post-processing device according to the first embodiment. [Figure 3] FIG. 4 is a schematic diagram of the edge binding processing section as seen from the discharge port side. [Figure 4] 5A and 5B are schematic diagrams illustrating the configuration of crimping teeth of the crimp-end binding processing section. [Figure 5] FIG. 4 is a diagram showing movement positions of an edge binding processing unit. [Figure 6] 5A and 5B are schematic diagrams illustrating the operation of the saddle stitching processing section. [Figure 7] FIG. 6 is a cross-sectional view showing the operation of the saddle stitching processing section. [Figure 8] FIG. 10 is a schematic diagram showing the pressing state of the saddle stitching processing section. [Figure 9] 1 is a schematic diagram of a press-bonded saddle-stitched booklet bound in the first embodiment. [Figure 10] FIG. 2 is a hardware configuration diagram of a control unit of the post-processing device. [Figure 11] FIG. 10 is a schematic diagram showing a first modified example of the saddle stitching processing section. [Figure 12] BB cross-sectional view showing the operation of the saddle stitching processing unit according to the first modification. [Figure 13] 10A and 10B are cross-sectional views showing the operation of the saddle stitching processing unit according to the second modified example. [Figure 14] 10A and 10B are cross-sectional views showing the operation of the saddle stitching processing unit according to the third modified example. [Figure 15] 10A and 10B are cross-sectional views showing the operation of the saddle stitching processing unit according to the fourth modification. [Figure 16] 13A and 13B are cross-sectional views showing the operation of the saddle stitching processing unit according to the fifth modified example. [Figure 17] Schematic diagram of a laminated saddle-stitched booklet bound using variant example 5. [Figure 18] FIG. 13 is a schematic diagram showing a sixth modified example of the saddle stitching processing section. [Figure 19] Schematic diagram of a laminated saddle-stitched booklet bound using variant example 6. [Figure 20] 13A and 13B are cross-sectional views showing the operation of the seventh modified example of the saddle stitching processing section. [Figure 21] FIG. 10 is a diagram showing the overall configuration of an image forming system according to a second embodiment. [Figure 22] FIG. 10 is a diagram showing the internal structure of a post-processing device according to a second embodiment. [Figure 23] FIG. 13 is a schematic diagram showing an eighth modified example of the saddle stitching processing section. [Figure 24]13A and 13B are cross-sectional views showing the operation of the saddle stitching processing unit according to Modification 8. [Figure 25] FIG. 13 is a schematic diagram showing an eighth modified example of the saddle stitching processing section. [Figure 26] FIG. 13 is a schematic diagram showing a saddle stitching processing unit according to a ninth modified example. [Figure 27] 10A and 10B are cross-sectional views showing the operation of a saddle stitching processing unit according to a modified example 10; DETAILED DESCRIPTION OF THE INVENTION

[0012] [First embodiment] A first embodiment of a sheet processing apparatus, a sheet processing method, and an image forming system according to the present invention will be described below with reference to the drawings. Fig. 1 is a diagram showing the overall configuration of an MFP 100 as an embodiment of an image forming system. As shown in Fig. 1, the MFP 100 includes an image forming apparatus 101 that forms an image on paper P, which corresponds to an example of a sheet material as a sheet-like medium, and a post-processing apparatus 110 that performs predetermined post-processing on the paper P on which the image has been formed. The MFP 100 corresponds to an embodiment of an internal image forming system in which the post-processing apparatus 110 is disposed in the internal space of the image forming apparatus 101.

[0013] The image forming apparatus 101 forms an image on a sheet P and discharges the sheet P with the image formed thereon to a post-processing device 110. The image forming apparatus 101 includes a tray for storing the sheet P, a transport unit for transporting the sheet P stored in the tray, and an image forming unit for forming an image on the sheet P transported by the transport unit. The image forming unit is capable of performing a well-known image forming method. For example, it may be an inkjet method in which liquid ink is ejected and adhered to the sheet P to form an image, or an electrophotographic method in which an image is formed using toner. The configuration and operation of the image forming apparatus 101 correspond to those well-known, and therefore a detailed description thereof will be omitted.

[0014] Next, a post-processing device 110 as an embodiment of a sheet processing device according to the present invention will be described in detail. Fig. 2 is a diagram showing the internal structure of the post-processing device 110 according to the first embodiment. The post-processing device 110 has a function of performing post-processing on sheets P on which images have been formed by the image forming device 101, and receives sheets P on which images have been formed from an inlet 1100 that receives sheets P from the image forming device 101, and performs binding processing to bind a sheet bundle Pb formed by bundling multiple sheets together.

[0015] More specifically, the binding process according to this embodiment includes "pressure binding," which binds a paper stack Pb formed by stacking multiple sheets of paper P by applying pressure to the binding position to deform the sheets, and "staple binding," which binds the paper stack Pb using staples at the binding position. Furthermore, pressure binding includes an end binding process that binds the ends of the paper stack Pb, and a saddle binding process that binds the center of the paper stack Pb.

[0016] The post-processing device 110 includes a first conveying roller pair 111 and a second conveying roller pair 112 for conveying the paper P carried in through the carry-in entrance 1100 along a conveying path. The first conveying roller pair 111 and the second conveying roller pair 112 convey the paper P supplied from the image forming device 101 along the first conveying path Ph1 inside the post-processing device 110.

[0017] The first transport path Ph1 is a path extending from an entrance 1100 through which the paper P is transported from the image forming apparatus 101 to the internal tray 114.

[0018] [Edge Binding Processing] The post-processing device 110 includes a return conveying roller 113, an internal tray 114, an end fence 115, a side fence 116 (not shown), a staple end binding processing unit 117 and a crimp end binding processing unit 118 as end binding processing units, a pair of discharge rollers 119, and a discharge tray 120.

[0019] The return conveyance rollers 113 constitute conveyance rollers for conveying the paper P that has passed through the second conveyance roller pair 112 toward the end fence 115 while placing the paper P on the internal tray 114. The conveyance direction of the return conveyance rollers 113 is different from the conveyance direction of the first conveyance roller pair 111 and the second conveyance roller pair 112, and corresponds to a direction that switches back (reverse direction) from the conveyance direction of the first conveyance roller pair 111 and the second conveyance roller pair 112. Therefore, conveyance by the return conveyance rollers 113 is referred to as switchback conveyance.

[0020] The first conveying roller pair 111, the second conveying roller pair 112, and the return conveying roller 113 convey the paper P as the sheet material to the internal tray 114 for binding processing. The first conveying roller pair 111, the second conveying roller pair 112, the return conveying roller 113, and the first conveying path Ph1 constitute a conveying means for conveying the paper P to the internal tray 114 as a stacking means.

[0021] The internal tray 114 corresponds to a stacking means for temporarily placing multiple sheets of paper P that are conveyed sequentially. The sheets of paper P placed on the internal tray 114 are switchback-conveyed by the return conveyance roller 113 to a position where they collide with the end fence 115. The end fence 115 constitutes an alignment member for aligning the ends of the sheets of paper P in the conveying direction during switchback conveyance. The end fence 115 aligns the ends of the multiple sheets of paper P stacked on the internal tray 114, forming a paper stack Pb.

[0022] 2, a pair of side fences 116 are arranged in the width direction of the internal tray 114 (width direction of the paper P). In other words, in the direction perpendicular to the conveyance direction of the paper P by switchback conveyance, i.e., the conveyance direction when the paper P is conveyed to the end fence 115, a pair of side fences 116 are arranged on both side ends of the internal tray 114.

[0023] The side fences 116 perform a "jogger action" by repeatedly contacting and separating from the widthwise edges of the multiple sheets of paper P loaded on the internal tray 114. This jogger action also aligns the widthwise edges of the multiple sheets of paper P. In other words, the side fences 116 constitute alignment members for aligning both widthwise edges (both edges perpendicular to the conveying direction) of the sheets of paper P loaded on the internal tray 114.

[0024] The staple end binding processing unit 117 and the pressure end binding processing unit 118 as end binding processing units perform binding processing on the end of the sheet bundle Pb aligned by the end fence 115 and the side fence 116.

[0025] After the binding process is performed, the return conveyance rollers 113 come into contact with the sheet bundle Pb placed on the internal tray 114 and rotate. The rotation direction at this time is opposite to the rotation direction during switchback conveyance. Therefore, the return conveyance rollers 113 discharge the sheet bundle Pb that has been edge-stitched from the first discharge opening 1101 toward the discharge tray 120.

[0026] There are several types of "end binding processes" that the staple end binding processing unit 117 and the crimp end binding processing unit 118 perform on the paper stack Pb. For example, these include a "parallel binding process" that performs binding along one side of the paper stack Pb that is parallel to the main scanning direction, a "diagonal binding process" that performs binding at a corner of the paper stack Pb, and a "two-point binding process" that performs binding at multiple points spaced apart in the width direction along one side of the paper stack Pb that is parallel to the conveyance direction.

[0027] 3 is a schematic diagram of the edge binding processing unit 1110, which includes the staple-end binding processing unit 117 and the crimp-end binding processing unit 118, as seen from the first discharge opening 1101 in the direction of the end fence 115. As shown in FIG. 3, the edge binding processing unit 1110 is attached to an edge binding processing unit base member 151 with the staple-end binding processing unit 117 and the crimp-end binding processing unit 118 spaced apart from each other in the main scanning direction, and is supported by a guide shaft 152 extending in the main scanning direction via this edge binding processing unit base member 151. Therefore, both the staple-end binding processing unit 117 and the crimp-end binding processing unit 118 are supported so as to be movable along the guide shaft 152.

[0028] The staple end binding processing unit 117 includes a staple end binding main scanning movement motor 161, a drive force transmission mechanism 162, and a staple end binding processing unit base member 163, and is configured to be movable in the main scanning direction along the guide shaft 152 by the drive force of the staple end binding main scanning movement motor 161.

[0029] The staple-end binding main scanning movement motor 161 generates a driving force for moving the staple-end binding processing unit 117. The driving force transmission mechanism 162 transmits the driving force of the staple-end binding main scanning movement motor 161 to a staple-end binding processing unit base member 163 via a pulley and a timing belt. This makes it possible for the staple-end binding processing unit 117 to move in the main scanning direction along the guide shaft 152.

[0030] Furthermore, the staple-end binding processing unit 117 includes a staple-end binding posture rotation motor 164, and rotates relative to the staple-end binding processing unit base member 163 around a staple-end binding rotation shaft 165 as the center of rotation.

[0031] The staple-end binding processing unit 117 also includes a staple-end binding clinch motor 166, and performs the staple binding process by opening and closing a staple clincher 167 to pierce and clinch the paper stack Pb with staples.

[0032] The crimped end binding processing unit 118 includes a crimped end binding main scanning movement motor 171, a drive force transmission mechanism 172, and a crimped end binding processing unit base member 173, and is configured to be movable in the main scanning direction along the guide shaft 152 by the drive force of the crimped end binding main scanning movement motor 171.

[0033] The crimp-end binding main scanning movement motor 171 generates a driving force for moving the crimp-end binding processing unit 118. The driving force transmission mechanism 172 transmits the driving force of the crimp-end binding main scanning movement motor 171 to the crimp-end binding processing unit base member 173 via pulleys and a timing belt. This allows the crimp-end binding processing unit 118 to move in the main scanning direction along the guide shaft 152.

[0034] Furthermore, the crimp-end binding processing section 118 includes a crimp-end binding posture rotation motor 174, and rotates relative to the crimp-end binding processing section base member 173 around a crimp binding rotation shaft 175 as the center of rotation.

[0035] The crimp-end binding processing unit 118 also includes a crimp-end binding clinch motor 176, and the driving force of the crimp-end binding clinch motor 176 causes an "opening and closing operation" in which the upper crimping teeth 177 approach or move away from the lower crimping teeth 178. This opening and closing operation allows the end of the paper-sheet bundle Pb to be sandwiched between the uneven upper and lower crimping teeth 177 and 178, causing pressure deformation. This pressure deformation causes the fibers of the sheets P that make up the paper-sheet bundle Pb to become entangled, and a single paper-sheet bundle Pb made up of multiple sheets P is formed. This binding process using pressure deformation is referred to as "pressure binding."

[0036] FIG. 4 is a schematic diagram showing the configuration of upper and lower crimping teeth 177 and 178 as a crimping unit included in the crimp-end binding processing unit 118. As shown in FIG. 4, the crimping unit includes a pair of upper and lower crimping teeth 177 and 178. The upper and lower crimping teeth 177 and 178 are arranged opposite each other in the thickness direction of the sheet stack Pb so as to be able to sandwich the sheet stack Pb placed on the internal tray 114. The upper and lower crimping teeth 177 and 178 are formed in an uneven shape with alternating concave and convex portions. Furthermore, the upper and lower crimping teeth 177 and 178 are formed with the concave and convex portions misaligned so as to mesh with each other. The crimping unit is configured so that the upper crimping teeth 177 open and close (contact and separation) with respect to the lower crimping teeth 178 by the driving force of a crimp-end binding clinch motor 176.

[0037] When the plurality of sheets P constituting the sheet bundle Pb are being supplied to the internal tray 114, the upper and lower pressure teeth 177 and 178 are spaced apart, as shown in FIG. 4A. Once all of the sheets P constituting the sheet bundle Pb have been placed on the internal tray 114 and a predetermined alignment operation (operation of aligning the edges) has been completed, the pressure-end binding processing unit 118 moves to the binding position, and the upper and lower pressure teeth 177 and 178 approach and mesh together, as shown in FIG. 4B. That is, the upper and lower pressure teeth 177 and 178 sandwich the predetermined binding position for the sheet bundle Pb, pressuring and deforming the sheet bundle Pb in the thickness direction. This causes the sheet bundle Pb placed on the internal tray 114 to be pressure-bound. The pressure-bound sheet bundle Pb is then discharged by the discharge roller pair 119 from the first discharge opening 1101 toward the discharge tray 120.

[0038] The crimp-end binding processing unit 118 only needs to perform the function of applying pressure to the sheet stack Pb and crimping a specific position, so it is sufficient if the upper and lower crimping teeth 177 and 178 can mesh and apply pressure when the sheet stack Pb is sandwiched between them and bound. Therefore, the configuration capable of closing the upper and lower crimping teeth 177 and 178 is not limited to the exemplary configuration disclosed in this embodiment. For example, a link mechanism-type crimping mechanism (such as that disclosed in Japanese Patent No. 6057167) that uses a drive source and a link mechanism that rotates forward or backward and performs the actions of moving the upper and lower crimping teeth 177 and 178 toward (crimping) and away from each other may be used. Alternatively, a linear-type crimping mechanism that linearly performs the actions of pressing and separating the upper and lower crimping teeth 177 and 178 from each other may be used.

[0039] 3, the crimping unit is provided with a binding tooth slide mechanism for moving the upper crimping teeth 177 and the lower crimping teeth 178 relative to the frame of the crimp-end binding processing unit 118. The binding tooth slide mechanism is composed of a binding tooth slide motor 179 and a drive transmission mechanism as a linear motion conversion mechanism such as a rack-and-pinion mechanism or a crankshaft mechanism that transmits the driving force of the binding tooth slide motor 179. When the driving force from the binding tooth slide motor 179 is transmitted to the upper crimping teeth 177 and the lower crimping teeth 178 by the drive transmission mechanism, the upper crimping teeth 177 and the lower crimping teeth 178 slide along their respective longitudinal directions (the longitudinal direction of the end-binding processing unit base member 151).

[0040] Here, the amount of slide movement of the upper crimping teeth 177 and the lower crimping teeth 178 is, for example, equal to the length of the crimp mark. The upper crimping teeth 177 and the lower crimping teeth 178 perform the crimp binding operation multiple times before and after the slide movement. That is, when the length of the crimp mark by the upper crimping teeth 177 and the lower crimping teeth 178 is 10 mm, by also setting the amount of slide movement to 10 mm, it is possible to obtain a crimp mark length of 20 mm in width by combining the crimping operation before the slide movement (first hit) and the crimping operation after the slide movement (second hit), and the binding force is improved by approximately two times.

[0041] [Binding process overview] 5A and 5B are diagrams illustrating the positions of the staple-end binding processing unit 117 and the crimp-end binding processing unit 118 according to the process steps. FIG. 5A illustrates a standby state (standby state) for the binding process. As shown in FIG. 5A, in the standby state, the staple-end binding processing unit 117 is located at a staple-binding standby position HP1. The crimp-end binding processing unit 118 is located at a crimp-binding standby position HP2.

[0042] 5(b) and 5(c) illustrate an example of how the crimp-end binding processing unit 118 performs the diagonal binding process. As shown in FIG. 5(b), before the first sheet P1 of the sheet bundle Pb is supplied to the internal tray 114, the crimp-end binding processing unit 118 is moved in the main scanning direction and rotated diagonally so that the crimp-end binding processing unit 118 faces the first binding position B1. The movement and rotation of the crimp-end binding processing unit 118 are controlled by a controller 190 serving as a control means, which will be described later with reference to FIG.

[0043] 5(c), the controller 190, with the crimp-end binding processing unit 118 positioned opposite the first binding position B1, executes a jogging operation each time a sheet P is transported to the internal tray 114. The jogging operation is executed by the controller 190 controlling the side fences 116 to slide in the width direction.

[0044] Next, in the state illustrated in FIG. 5(c), the controller 190 repeats the stacking and aligning operations of the sheets P until the number of sheets P for constituting the sheet bundle Pb reaches a predetermined number N.

[0045] Next, when the controller 190 detects that the number of sheets P placed on the internal tray 114 has reached a predetermined number N, it operates the crimp end binding processing unit 118 to perform a crimp binding operation on the first binding position B1 of the stack of sheets Pb placed on the internal tray 114.

[0046] Next, the controller 190 discharges the sheet bundle Pb that has been press-stitched at the first binding position B1 onto the discharge tray 120. Furthermore, the controller 190 moves the press-end binding processing unit 118 to the press-stitch standby position HP2 shown in FIG. 5(a).

[0047] 5(d) and 5(e) illustrate an example of how two-point binding is performed by the staple-end binding processing unit 117. The second binding position B2 and the third binding position B3 are spaced apart from each other in the main scanning direction. Before the first sheet P1 of the sheet bundle Pb is supplied to the internal tray 114, the controller 190 moves the staple-end binding processing unit 117 in the main scanning direction so that the staple-end binding processing unit 117 faces the second binding position B2. Next, as shown in FIG. 5(d), with the staple-end binding processing unit 117 moved to a position where it can face the second binding position B2, the controller 190 causes the side fence 116 to perform a jogging operation.

[0048] Next, in the state illustrated in FIG. 5(d), the controller 190 repeats the stacking and aligning operations of the sheets P until the number of sheets P for constituting the sheet bundle Pb reaches a predetermined number N.

[0049] Next, when the controller 190 detects that the number of sheets P placed on the internal tray 114 has reached a predetermined number N, it operates the staple end binding processing unit 117 to perform a staple binding operation on the first binding position B1 of the stack of sheets Pb placed on the internal tray 114.

[0050] Next, as shown in FIG. 5(e), the controller 190 causes the staple end binding processing unit 117 to face the third pressure binding position B3, and performs a staple binding operation on the third binding position B3 of the paper stack Pb placed on the internal tray 114.

[0051] 5, in two-point binding, the binding process is performed at the second binding position B2 and then at the third binding position B3. However, the order in which two-point binding is performed is not limited to this. That is, two-point binding may be performed by binding at the third binding position B3 and then at the second binding position B2. In cases where the number of sets to be bound is consecutive, for example, odd-numbered sets are bound at the second binding position B2 and then at the third binding position B3, and even-numbered sets are bound at the third binding position B3 and then at the second binding position B2. In this way, by performing the binding process by changing the order of the binding positions depending on the order of the total number of sets to be bound, the efficiency of the binding process can be improved.

[0052] Next, the controller 190 discharges the sheet bundle Pb stapled at the second pressure binding position B2 and the third pressure binding position B3 onto the discharge tray 120. Furthermore, as shown in FIG. 5(a), the controller 190 moves the staple-end binding processing unit 117 to the staple standby position HP1.

[0053] In the above embodiment, examples of diagonal binding or two-point binding at the corners of the paper stack Pb have been described, but the present invention is also applicable to cases where three or more points of the paper stack Pb spaced apart in the main scanning direction are bound.

[0054] [Outline of the pressure binding processing unit] 2, details of the part of the configuration of post-processing device 110 that performs the pressure saddle stitching process will be described. As shown in Fig. 2, post-processing device 110 includes return conveyance rollers 113, an internal tray 114, and a side fence 116 (not shown), as well as a movable end fence 131, a folding blade 132, a folding roller pair 133, a folding blade engagement roller 134, a center-folded booklet discharge roller pair 135, and a center-folded booklet discharge tray 136.

[0055] The movable end fence 131, the folding blade 132, and the pair of folding rollers 133 constitute a center folding means. The folding blade 132, the pair of folding rollers 133, and the folding blade engaging roller 134 constitute a pressure saddle stitching means.

[0056] The movable end fence 131 is a mechanism that moves the position of the end of the paper P placed on the internal tray 114 in the conveying direction, and aligns the center folding position, which is set near the center of the paper P in the conveying direction, with the position of the folding blade 132.

[0057] After the sheets P corresponding to the predetermined number N of sheets P constituting the sheet bundle Pb are stacked on the internal tray 114 and the alignment process is completed, the movable end fence 131 moves to adjust the center-fold position of the sheet bundle Pb to a position facing the folding blade 132. Alternatively, at the stage where the predetermined number N of sheets P constituting the sheet bundle Pb are being placed, the position of the movable fence may be moved so that the center-fold position of the sheet bundle Pb is a position facing the folding blade 132, and then the sheets P may be placed on the internal tray 114. In either case, the center-fold position of the sheet bundle Pb is adjusted to a position where it is pushed by the folding blade 132 toward the folding roller pair 133. Then, with these adjustments made, the folding blade 132 pushes the sheet bundle Pb toward the folding roller pair 133, and the folding roller pair 133 and the folding blade engagement roller 134 operate to perform the pressure-bonding saddle stitching process.

[0058] More specifically, when the sheet P transported from the image forming apparatus 101 passes through the second transport roller pair 112 and is placed on the internal tray 114, the return transport roller 113 causes the sheet P to be switched back and transported toward the movable end fence 131. The series of steps leading up to this switchback transport corresponds to the transport step. At this time, the movable end fence 131 may have already moved to a position corresponding to the center-folding position, or may be in the same position as the end fence 115.

[0059] The internal tray 114 temporarily holds a plurality of sheets P that are conveyed sequentially. A movable end fence 131 that is movable toward the conveyance direction side of the end fence 115 is provided on the internal tray 114. This movable end fence 131 is a member that is movable in the conveyance direction of the sheets P along the internal tray 114. The movable end fence 131 is configured to move under the control of the controller 190 according to the conveyance direction length of the sheets P placed on the internal tray 114 (which is also synonymous with the conveyance direction length in switchback conveyance), thereby changing the position of the sheets P. The position of the movable end fence 131 is set so that the center position of the sheet P in the conveyance direction length is opposite the folding blade 132.

[0060] 2, the side fences 116 align the positions of the sheets P or the sheet stack Pb placed on the internal tray 114 in the main scanning direction (width direction). The pressure saddle stitching processing unit performs pressure saddle stitching on the sheet stack Pb aligned by the movable end fence 131 and the side fences 116. The sheet stack Pb that has been subjected to pressure saddle stitching is discharged by a pair of center-folded booklet discharge rollers 135 and loaded onto a center-folded booklet discharge tray 136 through a second discharge port 1103.

[0061] [Operation of pressure binding method] Next, the operation of the pressure saddle stitching processing means will be described with reference to FIG. 6 and other figures. FIG. 6 is a schematic diagram that mainly shows a folding blade 132 as a folding plate member that constitutes the pressure saddle stitching processing means, a folding roller pair 133 as a folding roller pair member, and a folding blade engagement roller 134 as a folding plate engagement member, and outlines the center-fold binding process performed by these operations. FIG. 6(a) illustrates a state in which, after the conveying process and the stacking process, the sheet stack Pb is stacked on the internal tray 114, the edges of the sheets P are aligned, and the positions of all the sheets P are aligned. In FIG. 6(a), the folding blade 132, the folding roller pair 133, and the folding blade engagement roller 134 are located in their initial positions.

[0062] The initial position of the folding blade 132 is a position spaced from the surface of the sheet bundle Pb in a direction substantially perpendicular to the sheet bundle Pb. In the initial position, the folding blade 132 faces a folding position where the sheet bundle Pb is folded in the middle, and is configured to move back and forth in the thickness direction of the sheet bundle Pb by a folding blade movement motor 141 (FIG. 10) that constitutes a folding plate member movement mechanism. The folding blade 132 moves back and forth relative to the sheet bundle Pb between a push-in position for forming a fold in the middle folding process of folding the central portion of the sheet bundle Pb in the conveyance direction length as part of the sheet bundle Pb, and a retracted position where the folding blade 132 is removed from the sheet bundle Pb after folding the center of the sheet bundle Pb. The retracted position of the folding blade 132 corresponds to the initial position (HP position).

[0063] As shown in Fig. 6, the folding blade 132 is a plate-like member having a predetermined thickness, and has folding blade pressure teeth 132a formed on the surface (side surface) that faces the folding blade engagement roller 134 and pushes out the stack of paper-sheets Pb. The folding blade 132 has both end (corner) shapes in the thickness direction of the plate (plate thickness direction) that protrude beyond the folding blade pressure teeth 132a. These protruding portions are called flanges 132b. The flanges 132b are formed on both sides of the plate-like folding blade 132. The flanges 132b protrude by the same length in the direction in which the folding blade 132 moves (the direction relative to the folding blade engagement roller 134).

[0064] The shape of the flange portion 132b of the folding blade 132 may be a shape that protrudes perpendicularly to the folding blade crimping tooth portion 132a, or may be a shape that is inclined so as to guide the paper stack Pb toward the folding blade crimping tooth portion 132a.

[0065] The pair of folding rollers 133 are arranged symmetrically with respect to the center line of the folding blade 132. That is, the pair of folding rollers 133 are arranged at symmetrical positions with respect to the center line in the movement direction when the folding blade 132 performs a center-folding operation on the sheet P. The pair of folding rollers 133 are configured to be rotated by a folding roller pair rotation motor 142 (see FIG. 10). The pair of folding rollers 133 are also configured to be able to move toward and away from each other by a folding roller pair contact / separation motor 143 (see FIG. 10) that constitutes a pressure mechanism.

[0066] The distance between the pair of rollers constituting the folding roller pair 133 is adjusted under the control of the controller 190. When the sheet stack Pb is pushed by the folding blade 132 toward the nip position of the folding roller pair 133, the pair of rollers of the folding roller pair 133 are set to an "acceptance position" under the control of the controller 190, where the nip position is spaced apart according to a predetermined separation amount. Note that the controller 190 may set the position of the folding roller pair 133 to a position spaced apart from the acceptance position before the start of the center-folding process. The "acceptance position" of the folding roller pair 133 when accepting the sheet stack Pb is also the standby position during the center-folding and binding process, and therefore also corresponds to the standby position.

[0067] The folding blade engagement roller 134, which constitutes the pressure binding means, is a disk-shaped member having a predetermined thickness, and is provided with a rotation axis that penetrates the disk in the thickness direction, and is supported so as to be rotatable around this rotation axis. The folding blade engagement roller 134 is provided with engagement pressure teeth 134a having an uneven shape on the outer periphery of the disk (the outer periphery of the disk). The thickness of the folding blade engagement roller 134 (the dimension in the rotation axis direction) is preferably thinner than the formation interval of the flange portions 132b of the folding blade 132 (the thickness of the folding blade 132).

[0068] The engagement and crimping teeth 134a of the folding blade engagement roller 134 are gear-shaped portions in which irregularities are repeatedly formed at predetermined intervals on the cylindrical outer circumferential surface of the folding blade engagement roller 134. These irregularities are formed parallel to the rotation axis of the folding blade engagement roller 134.

[0069] The pressure-bonding saddle-stitching process according to this embodiment first executes a center-folding process. In the center-folding process, the controller 190 first adjusts the positions of the pair of rollers constituting the folding roller pair 133 using the folding roller pair contact / separation motor 143 to make the sheet stack Pb ready to be received. The folding roller pair contact / separation motor 143 adjusts the gap at the nip position of the folding roller pair 133. The adjustment amount (separation amount) of the gap at the nip position by the folding roller pair contact / separation motor 143 is intended to create a gap large enough for the folding blade 132 to push the center of the sheet stack Pb in the conveyance direction (length direction) into the nip position (gap) of the folding roller pair 133 and for the folding blade 132 to advance through the nip position while pushing the sheet stack Pb. Therefore, the adjustment amount of the gap at the receiving position of the folding roller pair 133 is changed depending on the predetermined number N of sheets P constituting the sheet stack Pb and size information including the size and thickness of the sheets P.

[0070] That is, as a preliminary step to the center folding process, when the folding blade 132 guides the sheet bundle Pb to the gap (nip position) between the rollers of the folding roller pair 133, the controller 190 separates the rollers to allow the folding blade 132 and the sheet bundle Pb to pass between the rollers. At this time, at the "receiving position" which is the position of the rollers constituting the folding roller pair 133, for example, the outer peripheries of the rollers are slightly separated from each other.

[0071] 6(b), the folding blade 132 guides the sheet bundle Pb toward the nip position of the folding roller pair 133. At this time, the folding roller pair 133 is pressed against the folding blade 132 by the elastic force of the folding roller pair pressure member 144 (see FIG. 8). In other words, the degree to which the sheet bundle Pb is pressed against the folding blade 132 is determined by the elastic force of the folding roller pair pressure member 144.

[0072] Information for adjusting the receiving position of the pair of folding rollers 133 (the type and thickness of the sheets P, and the number of sheets P constituting one unit of the sheet bundle Pb) is set in advance in the controller 190 via the operation panel 102. That is, when starting the center-folding process, the controller 190 calculates an adjustment value based on the number of sheets P constituting the sheet bundle Pb that have already been set, the type of sheets P (mainly differences in thickness), and the like, and uses the value obtained by adding the thickness of the folding blade 132 to this as the gap adjustment amount.

[0073] As shown in FIG. 6B, folding blade 132, which serves as a rack-type pressure blade, advances toward folding roller pair 133, the gap of which has been adjusted, while pushing sheet bundle Pb. At this time, folding roller pair 133, which serves as a center folding means, rotates in accordance with the advancement speed of folding blade 132 while pressing sheet bundle Pb in a direction perpendicular to the advancement direction. That is, folding blade 132 and sheet bundle Pb, which is guided by the advancement of folding blade 132, are pushed between folding roller pair 133. When sheet bundle Pb is pushed into folding roller pair 133, the pushed-in position of sheet bundle Pb is folded, thereby performing center folding. When folding blade 132 guides (pushes) sheet bundle Pb between folding roller pair 133, the gap between folding roller pair 133 is widened by an amount equivalent to twice the thickness of sheet bundle Pb.

[0074] 6(c), the tip of folding blade 132 continues to move to a position sufficiently beyond the nip position of folding roller pair 133, and the center-folding process for sheet stack Pb proceeds. During this center-folding process, a portion of sheet stack Pb (a portion approximately at the center in the conveying direction) becomes fold portion Fp (see FIG. 9). When the center-folding process shown in FIGS. 6(b) and 6(c) is being performed, folding blade engagement roller 134 is located in a retracted position spaced apart from the tip of folding blade 132 that has passed the nip position, as shown in FIG. 6(c).

[0075] 6(d), the folding blade engagement roller 134 moves from the retracted position toward the folding blade 132. The destination of this movement is the engagement position where the folding blade engagement roller 134 and the folding blade 132 come into contact with each other with the stack of sheets Pb interposed therebetween. When the folding blade engagement roller 134 moves to the engagement position, the folding blade 132 and the folding blade engagement roller 134 enter a pressing state in which they sandwich the stack of sheets Pb. In this pressing state, the folding blade pressing teeth 132a formed on the folding blade 132 and the engagement pressing teeth 134a formed on the outer circumferential surface of the disc of the folding blade engagement roller 134 mesh with each other to press the stack of sheets Pb from both sides, thereby performing pressure pressing.

[0076] Furthermore, while the fold portion Fp of the sheet stack Pb is being pressed against the sheet, the action of the flange portion 132b of the folding blade 132 and the folding blade engagement roller 134 causes a portion of the sheet stack Pb to go beyond the outer peripheral surface of the disk of the folding blade engagement roller 134 and reach the disk surface side of the folding blade engagement roller 134. The portion between the portions of the sheet stack Pb is pressed by the folding blade pressure teeth 132a and the engagement pressure teeth 134a. In other words, the sheet stack Pb is folded into a W shape in the direction opposite to the traveling direction of the folding blade 132. In this case, the position where the fold is formed (the folding position, also called the folding position) is determined by the flange portion 132b.

[0077] Therefore, the spine Cb of the paper stack Pb is formed with a width corresponding to the distance between the opposing flanges 132b, starting from the center of the length in the conveying direction. Also, fold lines f (see FIG. 9) are formed as fold lines at each position of the flanges 132b. The fold lines f formed at this time are formed in two places on either side of the spine Cb. In other words, this process corresponds to a spine pressure binding process in which the spine Cb is formed while forming the two fold lines f and, at the same time, pressure binding is performed on the spine Cb.

[0078] The controller 190 controls the operation of the folding blade 132 so as to maintain the pressing state of the folding blade 132 and the folding blade engagement roller 134 against the sheet bundle Pb, thereby forming the spine Cb, and causes the folding blade engagement roller 134 to scan in the width direction (main scanning direction) of the sheet bundle Pb. During this scanning in the width direction, the folding blade engagement roller 134 moves while rotating. In other words, while forming the spine Cb in the sheet bundle Pb, the controller 190 also controls the execution of the pressure binding process in parallel with this. This control process is referred to as the "spine pressure binding process."

[0079] In the spine pressure binding process, the flange portion 132b of the folding blade 132 and the folding blade engagement roller 134 enclose and pinch the sheet stack Pb protruding in the thickness direction of the folding blade engagement roller 134. As a result, a square spine is formed in the sheet stack Pb, and at the same time, pressure binding can be performed on the formed spine Cb. In other words, the operation described in FIG. 6(d) is both a spine forming process and a spine pressure binding process, and corresponds to a spine pressure binding process.

[0080] Finally, as shown in Figure 6(e), the controller 190 retracts the folding blade engagement roller 134 in the width direction of the sheet bundle Pb, and also retracts the folding blade 132 to the retracted position. Then, the controller 190 rotates the pair of folding rollers 133 to transport the sheet bundle Pb through the pair of folding rollers 133, and discharges the pressure-bonded saddle-stitched booklet with the spine Cb press-bound onto the center-folded booklet discharge tray 136 (see Figure 2). By folding the booklet into a W shape during the folding process, the finished booklet becomes a strong, spine-folded booklet that is difficult to open.

[0081] As described above, when performing saddle stitching on a sheet stack Pb, the post-processing device 110 according to this embodiment first performs a center folding process, and then performs a spine folding process to form a spine Cb of the center-folded sheet stack Pb. At the same time, it performs a pressure binding process on the spine Cb. That is, in the saddle stitching method according to an embodiment of the sheet processing method according to the present invention, the center folding process is followed by a spine forming process, and at the same time, a pressure binding process (spine pressure binding process) is performed on the spine Cb. As a result, unlike conventional methods, it is possible to form a pressure-saddle stitched booklet that is easy to open and that does not come apart due to folding processes and page turning operations.

[0082] 7 is a cross-sectional view showing the operation of the saddle stitching unit, as viewed from the paper conveyance direction side at the center position of the thickness of the folding blade 132. The center position of the thickness of the folding blade 132 corresponds to the centerline of the center fold. As already described, the folding blade 132 has folding blade pressure teeth 132a as uneven folding plate pressure teeth on the sheet material pushing surface that faces the folding blade engagement roller 134 in the traveling direction.

[0083] Fig. 7(a) corresponds to the state illustrated in Fig. 6(c). As already explained, in the state illustrated in Fig. 6(c), the folding blade 132 pushes the sheet stack Pb to a position beyond the nip position of the pair of folding rollers 133.

[0084] When the folding blade 132 pushes the sheet bundle Pb into the nip position of the folding roller pair 133 and advances, the folding blade engagement roller 134 waits at a position outside the width direction of the sheet bundle Pb that has been folded into a booklet when the center-folding process has been performed on the sheet bundle Pb. This standby position corresponds to the initial position (HP position). The folding blade engagement roller 134 in this initial position (HP position) is on the outside in the main scanning direction of the sheet bundle Pb that has been pushed into the nip position of the folding roller pair 133 and advances, and corresponds to a position where it is separated from the sheet bundle Pb. Note that FIG. 7 shows only the folding blade pressing tooth portion 132a of the components of the folding blade 132.

[0085] The folding blade engaging roller 134 (engagement pressure tooth portion 134a) is moved in the main scanning direction (width direction) by a folding blade engaging roller scanning motor 145 (FIG. 9). The saddle stitching processing section is provided with an engagement roller guide rail 146 as a folding blade engaging roller contact / separation mechanism, and the engagement pressure tooth portion 134a of the folding blade engaging roller 134 is configured to move in the main scanning direction along the engagement roller guide rail 146.

[0086] The engaging roller guide rail 146 has a dimension longer than the dimension of the sheet stack Pb in the main scanning direction, and the portion outside the end of the sheet stack Pb in the main scanning direction is spaced apart from the fold of the sheet stack Pb that has passed the nip position of the folding roller pair 133. Also, the engaging roller guide rail 146 is configured to approach the fold of the sheet stack Pb that has passed the nip position of the folding roller pair 133 at the portion inside the end of the sheet stack Pb in the main scanning direction.

[0087] Therefore, the engagement pressure tooth portion 134a of the folding blade engagement roller 134 does not come into contact with the fold formed on the bundle of paper-sheets Pb on the outside including the end in the main scanning direction, but moves to pinch the fold on the inside of the end in the main scanning direction with the folding blade 132. Then, as the engagement pressure tooth portion 134a moves in the main scanning direction along the engagement roller guide rail 146, the fold of the bundle of paper-sheets Pb is sequentially pinched at the positions where the folding blade 132 pinches it, thereby binding the bundle of paper-sheets Pb.

[0088] 7(b) corresponds to the state of FIG. 6(d). That is, this corresponds to a pressurized state in which the engagement pressure tooth portion 134a of the folding blade engagement roller 134 is pressed against the folding blade 132, pressurizing and deforming the sheet stack Pb sandwiched between the folding blade 132. When the folding blade engagement roller 134 is in a position to press the fold of the sheet stack Pb and the folding blade engagement roller 134 is scanning while forming the spine Cb by the folding blade engagement roller 134, the folding roller pair 133 is in a pressurized state to sandwich and not move the sheet stack Pb so as not to push back the sheet stack Pb. The controller 190 controls the folding roller pair 133 to maintain the pressurized state. That is, when the pressurized saddle stitching process is performed on the sheet stack Pb, the folding roller pair 133 is controlled to maintain the pressurized state so that the folding blade 132 does not retreat due to the pressure of the folding blade engagement roller 134.

[0089] Then, as the folding blade engagement roller 134 presses against the folding blade 132, the concave and convex teeth of the engagement crimping teeth portion 134a as engagement crimping teeth provided on the folding blade engagement roller 134 and the folding blade crimping teeth portion 132a as folding plate crimping teeth provided on the pushing surface of the folding blade 132 engage to sandwich the sheet stack Pb. As a result, the spine Cb of the sheet stack Pb is intermittently pressurized and deformed in the main scanning direction, and the spine crimp binding process is performed.

[0090] The folding blade pressure teeth 132a have recesses and protrusions arranged at predetermined intervals in the main scanning direction, like the rack teeth of a rack-and-pinion mechanism. When the folding blade engagement roller 134 is scanned in the main scanning direction by the folding blade engagement roller scanning motor 145 (FIG. 9), the meshing position between the engagement pressure teeth 134a of the folding blade engagement roller 134 and the folding blade pressure teeth 132a moves in the main scanning direction. This movement of the meshing position (engagement position) executes the pressure binding process for the spine Cb of the sheet stack Pb. While the pressure binding process is being executed, the folding roller pair 133 is kept pressed toward the nip position so that the folding blade engagement roller 134 can move back and forth in the main scanning direction while maintaining the engagement position. This prevents the sheet stack Pb and the folding blade 132 from escaping due to the pressure of the folding blade engagement roller 134.

[0091] In this way, when the engagement crimping teeth 134a approach the spine Cb formed on the stack of sheets Pb, they move diagonally from the outside in the width direction of the stack of sheets Pb toward the spine Cb. As a result, they approach from a direction that will not collide with the widthwise end of the spine Cb of the stack of sheets Pb, and the engagement position of the folding blade 132 with the folding blade crimping teeth 132a starts from the inside of the widthwise end of the stack of sheets Pb. This prevents the end from being turned up as it passes through the end of the stack of sheets Pb.

[0092] In FIG. 7C, after pressure binding is performed on the spine Cb of the sheet bundle Pb, the sheet bundle Pb is removed to a position retracted from the width of the sheet bundle Pb in the main scanning direction and is also separated in the center-fold discharge direction.

[0093] When the next sheet bundle Pb is subsequently press-stitched, the rollers move in the opposite main scanning direction, i.e., from left to right in FIG. 7(b) for odd-numbered sheets and from right to left in FIG. 7(b) for even-numbered sheets.

[0094] Although the folding blade engagement roller contact / separation mechanism according to this embodiment is configured using the engagement roller guide rail 146 and the folding blade engagement roller scanning motor 145 (FIG. 10), it is not limited to this. A movement motor that moves the folding blade engagement roller 134 forward and backward in the center-folding discharge direction may also be provided.

[0095] Fig. 8 is a schematic diagram showing a state when the saddle stitching unit presses the sheet stack Pb. As shown in Fig. 8, the folding blade 132 corresponds to a folding plate member that guides the vicinity of the center in the conveyance direction of the sheet stack Pb placed and stacked on the internal tray 114 toward the nip position of the pair of folding rollers 133, which is a predetermined direction. As already explained, the folding blade 132 is a plate-like member having a predetermined width (thickness), and is provided with a folding blade pressing tooth portion 132a on one of its side surfaces that faces the folding blade engagement roller 134. The folding blade 132 also has flange portions 132b provided on both surfaces of the plate.

[0096] The pair of folding rollers 133 corresponds to a pair of folding rollers that sandwich the sheet bundle Pb guided by the folding blade 132 and advancing toward the nip position, and further advances the sheet bundle Pb in the advancing direction.

[0097] That is, the folding roller pair 133 is urged toward the folding blade 132 by the folding roller pair pressure member 144 so that the folding roller pair 133 sandwiches the paper stack Pb with the folding blade 132 at the nip position. This urging causes the folding roller pair 133 to press the folding blade 132, which adds the nip position. Note that the folding roller pair pressure member 144 is an elastic member such as a spring, and so while pressing the folding roller pair 133 toward the folding blade 132, it is in a state in which it can be pushed back by its elastic force when the folding blade 132 and the paper stack Pb proceed between the folding roller pair 133 (the nip position).

[0098] 6(b) and 6(c), the pair of folding rollers 133 conveys the sheet stack Pb while pressing it toward the folding blade 132, so that the sheet stack Pb is folded as it passes between the pair of folding rollers 133 by being pressed against the fold by the end of the folding blade 132 in the direction of travel. Also, in the state of FIG. 6(d), with the pair of folding rollers 133 pressing the sheet stack Pb, the folding blade engagement roller 134 holds the sheet stack Pb during pressure binding.

[0099] The folding blade engaging roller 134 is pressed toward the folding blade 132 by a folding blade engaging roller pressure member 147. The folding blade engaging roller 134 is a roller-shaped member and is supported on a shaft. The rotation axis of the folding blade engaging roller 134 is the axis in the direction in which the folding roller pair 133 is biased against the folding blade 132.

[0100] The folding blade engaging roller 134 has an engaging and crimping tooth portion 134a as a cylindrical portion having a predetermined width in the rotation axis direction.

[0101] The engagement pressure tooth portion 134a presses the sheet stack Pb interposed between it and the folding blade 132 due to the biasing force of the folding blade engagement roller pressure member 147, thereby performing the pressure binding process. Then, by being pressed toward the folding blade 132 by the engagement pressure tooth portion 134a, the portion of the sheet stack Pb sandwiched between the flange portion 132b of the folding blade 132 and the folding blade engagement roller 134 is oriented in a direction along the flange portion 132b of the folding blade 132. As a result, the portion of the sheet stack Pb sandwiched between the flange portion 132b of the folding blade 132 and the folding blade engagement roller 134 is folded into a W shape.

[0102] This folding direction is opposite to the direction of entry of the folding blade 132. The folded portions at this time are formed at two locations spaced a predetermined distance apart in the thickness direction of the folding blade 132, so two fold lines are formed in the paper-sheet bundle Pb by the pressure binding operation. As a result, a square spine is formed at the folded portion of the paper-sheet bundle Pb, and a spine Cb, which is a substantially flat area, is formed between the fold lines. In other words, a square spine fold is performed by the pressure binding process.

[0103] [Booklet Bk] FIG. 9 is a perspective view illustrating a booklet Bk formed by the above-described crimping saddle stitching operation. As shown in FIG. 9, the booklet Bk is formed by folding the sheet bundle Pb at the crease Fp during the center-folding process, and a square spine is formed on the spine Cb. The spine Cb is then deformed by the engaging crimping teeth 134a and the folding blade 132, forming crimp marks Ct at predetermined intervals along the length of the spine Cb. These crimp marks Ct can be formed at positions that overlap with the positions (crease Fp) where the sheet bundle Pb is folded during the center-folding process. The booklet Bk has two creases f that form the spine Cb, which are movable when a page is turned. The two creases f are formed near both sides of the crimp marks Ct.

[0104] Therefore, the booklet Bk produced by the saddle stitching and pressure binding processes according to this embodiment has a structure in which, when a page is turned by the fold f due to a page turning operation, the load is not applied to the pressure-bonded portion, and therefore, the structure does not induce peeling of the bound portion due to the page turning operation. Furthermore, since the fold f is formed in two places on either side of the spine Cb, the fold f that moves during the page turning operation is one of the two places. This fold f is in a position that does not overlap with the fold portion Fp that is pushed into the nip position of the folding roller pair 133 by the folding blade 132. The fold portion Fp then becomes the binding position for the pressure binding process.

[0105] Therefore, when a page is turned, the page is turned at the fold f, and the fold portion Fp, which corresponds to the center when the booklet Bk is opened, is bound, so the page is not turned across the binding position. In other words, because the center fold lines (fold f) are symmetrical on both sides of the binding position, the left and right pages can be opened evenly, and the quality of the booklet Bk is maintained.

[0106] [Control configuration] 10 is a hardware configuration diagram of a controller 190 that controls the operation of the post-processing device 110 according to the first embodiment. As shown in Fig. 10, the controller 190 includes a central processing unit (CPU) 191, a random access memory (RAM) 192, a read only memory (ROM) 193, a hard disk drive (HDD) 194, and an interface (I / F) 1905, all of which are connected via a common bus 1906.

[0107] The CPU 1901 is a computing means and controls the overall operation of the post-processing device 110. The RAM 1902 is a volatile storage medium capable of reading and writing information at high speed, and is used as a work area when the CPU 1901 processes information. The ROM 1903 is a read-only non-volatile storage medium in which programs such as firmware are stored. The HDD 1904 is a non-volatile storage medium with a large storage capacity that is capable of reading and writing information, and in which an OS (Operating System), various control programs, application programs, etc. are stored.

[0108] The post-processing device 110 processes a control program stored in the ROM 1903, an information processing program (application program) loaded from a storage medium such as the HDD 1904 to the RAM 1902, and the like, using the arithmetic functions of the CPU 1901. This processing constitutes a software control unit including various functional modules of the post-processing device 110. The combination of the software control unit thus constituted and the hardware resources installed in the post-processing device 110 constitutes a functional block that realizes the functions of the post-processing device 110. In other words, the CPU 1901, RAM 1902, ROM 1903, and HDD 1904 constitute a controller 190 (control unit) that controls the operation of the post-processing device 110.

[0109] The I / F 1905 is an interface that connects the first conveying roller pair 111, the second conveying roller pair 112, the return conveying roller 113, the side fence 116, the discharge roller pair 119, the movable end fence 131, the folding blade moving motor 141, the folding roller pair rotation motor 142, the folding roller pair contact / separation motor 143, the folding blade engagement roller scanning motor 145, the staple end binding main scanning moving motor 161, the staple end binding posture rotation motor 164, the staple end binding clinch motor 166, the crimp end binding main scanning moving motor 171, the crimp end binding posture rotation motor 174, the crimp end binding clinch motor 176, the binding tooth slide motor 179, the crimping roller moving motor 188, and the operation panel 102 to the common bus 1906.

[0110] The controller 190 operates, via the I / F 1905, the first conveying roller pair 111, the second conveying roller pair 112, the return conveying roller 113, the side fence 116, the discharge roller pair 119, the movable end fence 131, the folding blade moving motor 141, the folding roller pair rotation motor 142, the folding roller pair contact / separation motor 143, the folding blade engagement roller scanning motor 145, the staple end binding main scanning moving motor 161, the staple end binding posture rotation motor 164, the staple end binding clinch motor 166, the crimp end binding main scanning moving motor 171, the crimp end binding posture rotation motor 174, the crimp end binding clinch motor 176, the binding tooth slide motor 179, and the crimp roller moving motor 188.

[0111] As already explained in FIG. 1, the image forming apparatus 101 includes an operation panel 102. The operation panel 102 includes an operation unit that accepts input operations from a user and a display (notification unit) that notifies the user of information. The operation unit includes, for example, hard keys, a touch panel superimposed on the display, etc. The operation panel 102 acquires information from the user through the operation unit and provides the information to the user through the display. Note that the notification unit is not limited to a display, and may be an LED lamp, a speaker, etc. Also, the post-processing device 110 may be provided with an operation panel 102 similar to the above.

[0112] [Variation 1] Next, a first modified example of the saddle stitching processing unit will be described with reference to Figures 11 and 12. The difference from the saddle stitching processing unit according to the first embodiment is that the folding blade engaging member is not a roller member that scans (rotates), but is configured as a folding blade engaging die 181 as a blade member that extends in the width direction. Note that components common to the saddle stitching processing unit according to the first embodiment are given the same reference numerals, and detailed description thereof will be omitted.

[0113] 11 is a schematic diagram showing a saddle stitching processing section according to Modification 1. The pair of folding rollers 133 sandwich the folding blade 132 and the sheet stack Pb, and are pressed against each other by a folding roller pair pressure member 144.

[0114] The folding blade engagement die 181 is pressed against the folding blade 132 with the paper stack Pb sandwiched therebetween by the folding blade engagement roller pressure member 147. By utilizing this pressing force, the die pressure-bonding portion 181a of the folding blade engagement die 181 performs pressure binding, and the flange portion 132b of the folding blade 132 performs a square spine fold.

[0115] Figure 12 is a cross-sectional view showing the operation of Variation 1 of the saddle stitching processing unit. It is a cross-sectional view taken along the BB line as seen from the paper conveyance direction side at the center line of the center fold, in other words, at the center position of the thickness of the folding blade 132. Figure 12(a) corresponds to the state shown in Figure 6(c). The folding blade 132 pushes the paper stack Pb to a position beyond the nip position of the pair of folding rollers 133, and the folding blade engagement die 181 is in the standby position (HP position) and is spaced apart from the paper stack Pb in the center fold discharge direction.

[0116] The folding blade engaging die 181 is moved toward the folding blade by a folding blade engaging die moving motor 182 (not shown).

[0117] Figure 12(b) corresponds to the state of Figure 6(d). The folding blade engagement die 181 is pressed against the folding blade 132, sandwiching the sheet bundle Pb, and the concave and convex teeth of the die pressure-bonding portion 181a of the folding blade engagement die and the folding blade pressure-bonding teeth portion 132a provided on the pushing surface of the folding blade 132 engage with each other, sandwiching the sheet bundle Pb. The folding blade engagement die 181 is pressed by the folding blade engagement die pressure member 183, so that the spine of the sheet bundle Pb is pressure-bonded and bound.

[0118] [Variation 2] Next, a second modified example of the saddle stitching processing section will be described with reference to FIG. 13. The difference from the first modified example of the saddle stitching processing section is that the folding blade 184 does not have uneven crimping teeth uniformly arranged in the width direction, but has crimping teeth arranged partially (intermittently) at multiple locations as a folding plate crimping tooth group. Also, the folding blade engaging die 185 has crimping teeth arranged as an engaging crimping tooth group at a position opposite the folding plate crimping tooth group. The portion where the engaging crimping tooth group is not arranged is a flat portion. Note that the same reference numerals are used for components common to the saddle stitching processing section according to the first embodiment, and detailed description thereof will be omitted.

[0119] Figure 13 is a cross-sectional view showing the operation of Variation 2 of the saddle stitching processing unit. It is a cross-sectional view seen from the paper conveyance direction side at the center line of the center fold, in other words, the center position of the thickness of the folding blade 132. Figure 13(a) corresponds to the state of Figure 6(c). The folding blade 184 pushes the paper stack Pb to a position beyond the nip position of the folding roller pair 133, and the folding blade engagement die 185 is located in the standby position (HP position) and is separated from the paper stack Pb in the center fold discharge direction.

[0120] The folding blade engaging die 185 is moved toward the folding blade by a folding blade engaging die moving motor 182 (not shown).

[0121] Figure 13(b) corresponds to the state of Figure 6(d). The folding blade engagement die 185 is pressed against the folding blade 184, sandwiching the sheet bundle Pb, and the concave and convex teeth of the pressure-bonding portion 185a of the folding blade engagement die and the concave and convex teeth 184a provided on the pushing surface of the folding blade 184 engage with each other, sandwiching the sheet bundle Pb. The folding blade engagement die 185 is pressed by the folding blade engagement die pressure member 183, so that the spine of the sheet bundle Pb is crimped and bound.

[0122] [Variation 3] Next, a third variation of the saddle stitching processing unit will be described with reference to Fig. 14. The difference from the first variation of the saddle stitching processing unit is that the folding blade engaging member does not move linearly facing the folding blade 132 to engage with it, but moves along a rotational trajectory so that the concave and convex crimping teeth sequentially engage with it. Note that the same reference numerals are used for components common to the saddle stitching processing unit according to the first embodiment, and detailed descriptions thereof will be omitted.

[0123] Figure 14 is a cross-sectional view showing the operation of Variation 3 of the saddle stitching processing unit. It is a cross-sectional view taken along the center line of the center fold. In other words, it is a cross-sectional view taken from the paper conveyance direction side at the center position of the thickness of the folding blade 132. Figure 14(a) corresponds to the state of Figure 6(c). In Figure 14(a), the folding blade 132 pushes the paper stack Pb to a position beyond the nip position of the folding roller pair 133, and the folding blade engagement die 186 is in the standby position (HP position) and is spaced apart from the paper stack Pb in the center fold discharge direction.

[0124] The folding blade engagement die 186 is moved toward the folding blade 132 by a folding blade engagement die moving motor 182 (not shown), and moves along a rotational trajectory so that the concave and convex teeth sequentially mesh with each other.

[0125] Figure 14(b) corresponds to the state of Figure 6(d). In Figure 14(b), the folding blade engagement die 186 is pressed toward the folding blade 132 so as to sandwich the paper-sheet bundle Pb, and the concave and convex teeth of the crimping portion 186a of the folding blade engagement die 186 and the folding blade crimping teeth portion 132a provided on the pushing surface of the folding blade 132 engage with each other, sandwiching the paper-sheet bundle Pb. When the folding blade engagement die 186 is pressed by the folding blade engagement die pressure member 183, the spine of the paper-sheet bundle Pb is crimped and bound.

[0126] The crimping portion 186a of the folding blade engaging die 186 is not flat but has a curved surface, and the curved surface may be provided with concave and convex teeth, and the folding blade engaging die 186 may move along a rotational trajectory so that the concave and convex teeth mesh sequentially.

[0127] In this way, the concave and convex teeth are sequentially meshed with each other, thereby reducing the pressure applied during crimp binding and realizing a more compact device.

[0128] [Variation 4] Next, a fourth variation of the saddle stitching processing unit will be described with reference to Fig. 15. The difference from the saddle stitching processing unit according to the first embodiment is that the folding blade 132 is provided with a pressure roller 187 having uneven teeth on its outer periphery that scans in the main scanning direction at the tip end. Note that components common to the saddle stitching processing unit according to the first embodiment are given the same reference numerals, and detailed descriptions thereof will be omitted.

[0129] Figure 15 is a cross-sectional view showing the operation of Variation 4 of the saddle stitching processing unit. It is a cross-sectional view seen from the center line of the center fold. In other words, it is a cross-sectional view seen from the paper transport direction side at the center position of the thickness of the folding blade 132. Figure 15(a) corresponds to the state of Figure 6(c). The folding blade 132 pushes the paper stack Pb to a position beyond the nip position of the folding roller pair 133, and the folding blade engagement roller 134 and pressure roller 187 are located in the standby position (HP position) and are separated from the paper stack Pb in the center fold discharge direction.

[0130] The pressure roller 187 as a first roller member is supported so as to be guided by the pressure roller rail 132c. The pressure roller rail 132c is disposed in the longitudinal direction (main scanning direction) of the folding blade 132. The pressure roller 187 is moved in the main scanning direction of the paper stack Pb by a pressure roller movement motor 188 (see FIG. 10).

[0131] Figure 15(b) corresponds to the state of Figure 6(d). The folding blade engagement roller 134 serving as a second roller member is guided by the engagement roller guide rail 146 to approach the pressure roller 187 and is pressed against the pressure roller 187 via the stack of sheets Pb. The uneven teeth of the engagement pressure tooth portion 134a of the folding blade engagement roller and the uneven teeth 187a provided on the pressing surface of the pressure roller 187 engage with each other, sandwiching the stack of sheets Pb. The folding blade engagement roller 134 is pressed by the folding blade engagement roller pressure member 147, so that the spine Cb of the stack of sheets Pb is pressure-bound.

[0132] [Variation 5] Next, a fifth modified example of the saddle stitching processing unit will be described with reference to Fig. 16. The difference from the first embodiment is that the concave and convex crimping teeth of the folding blade 184 are not uniformly arranged in the width direction, but are arranged partially (intermittently) at multiple spaced positions. Note that the folding blade 184 according to the fifth modified example has a flat shape in the portion other than the concave and convex portions of the surface on which the concave and convex shapes are formed (the surface facing the folding blade engagement roller 134). Note that the same reference numerals are used for components common to the first embodiment of the saddle stitching processing unit, and detailed description thereof will be omitted.

[0133] Figure 16 is a cross-sectional view showing the operation of Variation 5 of the saddle stitching processing unit. It is a cross-sectional view of the center line of the center fold. In other words, it is a cross-sectional view seen from the paper conveyance direction side at the center position of the thickness of the folding blade 132. Figure 16(a) corresponds to the state of Figure 6(c). The folding blade 132 pushes the paper stack Pb to a position beyond the nip position of the folding roller pair 133, and the folding blade engagement roller 134 is located in the standby position (HP position) and is separated from the paper stack Pb in the center fold discharge direction.

[0134] Figure 16(b) corresponds to the state of Figure 6(d). The folding blade engagement roller 134 is pressed against the folding blade 132, sandwiching the stack of sheets Pb, and the uneven teeth of the engagement pressure tooth portion 134a of the folding blade engagement roller and the folding blade pressure tooth portion 132a engage with each other, sandwiching the stack of sheets Pb. The folding blade engagement roller 134 is pressed by the folding blade engagement roller pressure member 147, so that the spine of the stack of sheets Pb is pressure-bound.

[0135] Fig. 17 is a schematic diagram of a booklet Bk formed in Modification 5. As illustrated in Fig. 17, the spine Cb of the booklet Bk is formed with a square spine. The spine Cb is intermittently press-bound, and press marks Ct are intermittently formed in the longitudinal direction of the spine Cb (the width direction of the paper stack Pb).

[0136] [Variation 6] Next, a sixth variation of the saddle stitching processing unit will be described with reference to Figures 18 and 19. The difference from the saddle stitching processing unit according to the first embodiment is that the engagement pressure tooth portions 134a of the folding blade engagement roller are not aligned perpendicular to the main scanning direction, but are configured, for example, in a "helical tooth" shape inclined relative to the main scanning direction. Here, the inclination angle of the engagement pressure tooth portions 134a is, for example, 15 degrees. Note that the same reference numerals are used for components common to the saddle stitching processing unit according to the first embodiment, and detailed description thereof will be omitted.

[0137] Fig. 19 is a schematic diagram of a press-stitched booklet bound in Modification Example 6. As illustrated in Fig. 19, the spine Cb of the booklet Bk is formed with a square spine. The spine Cb is press-stitched intermittently, and press marks Ct inclined in the main scanning direction are formed intermittently in the longitudinal direction of the spine Cb (the width direction of the paper stack Pb).

[0138] [Variation 7] Next, a seventh modified example of the saddle stitching processing unit will be described with reference to Fig. 20. The difference from the saddle stitching processing unit according to the first embodiment is that the scanning trajectory of the folding blade engagement roller 134 is configured to draw a figure eight. Note that components common to the saddle stitching processing unit according to the first embodiment are given the same reference numerals, and detailed description thereof will be omitted.

[0139] Figure 20 is a cross-sectional view showing the operation of Variant 7 of the saddle stitching processing section. It is a cross-sectional view at the center line of the center fold. In other words, it is a cross-sectional view seen from the paper conveyance direction side at the center position of the thickness of the folding blade 132. Figure 20(a) corresponds to the state of Figure 6(c). The folding blade 132 pushes the paper stack Pb to a position beyond the nip position of the folding roller pair 133, and the folding blade engagement roller 134 is located in the standby position (HP position) and is separated from the paper stack Pb in the center fold discharge direction.

[0140] The folding blade engaging roller 134 is supported on an engaging roller guide rail 146a. The folding blade engaging roller 134 is moved along the engaging roller guide rail 146a by a folding blade engaging roller scanning motor 145 (see FIG. 10). The movement of the folding blade engaging roller 134 is controlled by a controller 190 (FIG. 10).

[0141] The engagement roller guide rail 146a is arranged to connect between a position where the engagement crimping teeth 134a of the folding blade engagement roller 134 engage with the folding blade crimping teeth 132a of the folding blade 132, and a position where the engagement crimping teeth 134a are spaced apart from the folding blade 132. The engagement roller guide rail 146a brings the folding blade engagement roller 134 closer to the folding blade 132 in a predetermined section in the longitudinal direction, and separates it in other sections.

[0142] Figure 20(b) corresponds to the state of Figure 6(d). The folding blade engagement roller 134 is guided by the engagement roller guide rail 146a and is pressed toward the folding blade 132, sandwiching the bundle of sheets Pb, from a first predetermined position in the width direction of the bundle of sheets Pb. At this time, the concave and convex teeth of the engagement pressure tooth portion 134a of the folding blade engagement roller and the folding blade pressure tooth portion 132a provided on the pushing surface of the folding blade 132 engage with each other, sandwiching the bundle of sheets Pb. The folding blade engagement roller 134 is pressed by the folding blade engagement roller pressure member 147, so that the spine Cb of the bundle of sheets Pb is pressure-bound.

[0143] As shown in FIG. 20(b), the folding blade engagement roller 134 is guided by the engagement roller guide rail 146a and moves in the main scanning direction to a retracted position past the end of the paper stack, and press-stitches approximately half of the width of the paper stack Pb.

[0144] Subsequently, as shown in FIG. 20(c), the folding blade engaging roller 134 is guided by the engaging roller guide rail 146a, moves away from the sheet stack Pb again at the retreat position, and moves in the opposite direction in the main scanning direction.

[0145] Next, as shown in Figure 20(d), the folding blade engagement roller 134 is guided by the engagement roller guide rail 146a and moves in the main scanning direction from the second predetermined position, again pressing the paper stack Pb, until it passes the other end of the paper stack Pb.

[0146] The folding blade engagement roller 134 is guided by the engagement roller guide rail 146a and moves along a trajectory that traces a series of figure eights, thereby crimping and binding the entire width of the spine of the booklet. Details of the movement mechanism that traces the figure eight are similar to the movement mechanism disclosed in, for example, Japanese Patent No. 5858017.

[0147] The folding blade engagement roller 134 presses and deforms the spine Cb of the paper stack Pb, thereby crimping and folding the paper stack squarely. Because the crimping and folding are performed sequentially while scanning in the main scanning direction, the pressure can be concentrated at the processing point, reducing the pressure and enabling the device to be more compact. However, if unintended deformation of the paper stack (for example, paper wrinkles) occurs, the paper wrinkles will accumulate and expand as the paper stack is scanned in the main scanning direction.

[0148] The folding blade engagement roller 134 moves in a trajectory that traces a series of figure eights, so that the front half of the paper width is processed first from the center to the edge, and then the rear half is processed from the center to the edge. Even if unintended deformation of the paper stack (for example, paper wrinkles) occurs, the accumulation of paper wrinkles can be reduced by half.

[0149] [Variation 8] Next, an eighth modified example of the saddle stitching processing unit will be described with reference to Figure 23. The difference from the saddle stitching processing unit according to the first embodiment is that the folding blade pressing teeth 132a having an uneven shape are not provided on the pushing surface of the folding blade 132. Another difference from the first embodiment is that the cylindrical outer periphery of the folding blade engaging roller 191 is not provided with a configuration equivalent to the engaging pressing teeth 134a, and a reheating unit is provided on the cylindrical outer periphery of the folding blade engaging roller 191. Note that the same reference numerals are used for components common to the saddle stitching processing unit according to the first embodiment, and detailed description thereof will be omitted.

[0150] 23 is a schematic diagram showing the saddle stitching processing section in Modification 8. The pair of folding rollers 133 sandwich the folding blade 132 and the sheet stack Pb, and are pressed against each other by a folding roller pair pressure member 144.

[0151] The folding blade engagement roller 191 is pressed against the folding blade 132 with the paper stack Pb sandwiched therebetween by a folding blade engagement roller pressure member 147. By utilizing this pressure and heat, the heat and pressure bonding portion 191a of the folding blade engagement roller 191 performs toner pressure binding, and the flange portion 191b performs square spine folding.

[0152] The folding blade engagement roller 191, which constitutes the toner pressure binding means, is a cylindrical roller-shaped member, and has a rotation axis set in a direction penetrating both ends that sandwich the cylindrical outer periphery, and is supported so as to be rotatable around this rotation axis. The folding blade engagement roller 191 has a heat pressure bonding portion 191a on the cylindrical outer periphery (cylindrical outer periphery surface).

[0153] The heat-pressure bonding portion 191a of the folding blade engaging roller 191 is a portion that is heated by a heater installed inside the folding blade engaging roller 191.

[0154] Figure 24 is a cross-sectional view showing the operation of Variant 8 of the saddle stitching processing unit. It is a cross-sectional view of the center line of the center fold. In other words, it is a cross-sectional view taken along the line BB as seen from the paper transport direction side at the center position of the thickness of the folding blade 132. Figure 24(a) corresponds to the state of Figure 6(c). The folding blade 132 has pushed the paper stack Pb to a position beyond the nip position of the folding roller pair 133, and the folding blade engagement roller 191 is in the standby position (HP position) and is spaced apart from the paper stack Pb in the center fold discharge direction.

[0155] The folding blade engaging roller 191 (heat pressing unit 191a) is moved in the main scanning direction (width direction) by a folding blade engaging roller scanning motor 145 (FIG. 10). The saddle stitching processing unit is provided with an engaging roller guide rail 146 as a folding blade engaging roller contact and separation mechanism, and the folding blade engaging roller 191 is configured to move in the main scanning direction along the engaging roller guide rail 146.

[0156] Fig. 24(b) corresponds to the state of Fig. 6(d). The folding blade engagement roller 191 is pressed against the folding blade 132 with the paper stack Pb sandwiched therebetween, and the heat and pressure bonding portion 191a of the folding blade engagement roller is pressed against the pushing surface of the folding blade 132, and the paper stack Pb is heated and pressurized with the paper stack Pb sandwiched therebetween, whereby the spine of the paper stack Pb is pressure-bound.

[0157] Figure 25(a) is a schematic diagram of the sheet stack Pb before center folding and pressure binding in Modification 8, and corresponds to the state shown in Figure 6(a). As shown in Figure 25(a), an adhesive toner image tn is formed by an image forming device at a position corresponding to the fold of the booklet Bk. Details of the method for forming the adhesive toner image tn by an image forming device are well known, as disclosed in JP-A-2004-209858 and the like.

[0158] Fig. 25(b) is a schematic diagram of a booklet Bk formed in Modification Example 8. As illustrated in Fig. 25(b), a square spine is formed in the spine Cb of the booklet Bk. Then, in the spine Cb, the adhesive toner image tn is reheated and the booklet Bk is bound with toner pressure.

[0159] [Variation 9] Next, a saddle stitching processing unit according to Variation 9 will be described with reference to Fig. 26. The difference from the saddle stitching processing unit according to Variation 8 is that the heat-pressing unit is configured in the folding blade 192 (heat-pressing unit 192a) rather than in the folding blade engagement roller 191. Note that components common to the saddle stitching processing unit according to Variation 8 are given the same reference numerals, and detailed description thereof will be omitted.

[0160] 23 is a schematic diagram showing a saddle stitching processing section in a modified example 9. The pair of folding rollers 133 sandwich the folding blade 192 and the sheet stack Pb, and are pressed against each other by a folding roller pair pressure member 144.

[0161] Furthermore, the folding blade engagement roller 191 is pressed against the folding blade 132 with the paper stack Pb sandwiched therebetween by the folding blade engagement roller pressure member 147. By utilizing this pressure and heat, the heat and pressure bonding portion 192a of the folding blade 192 performs toner pressure binding, and the flange portion 192b performs square spine folding.

[0162] The heat-pressure bonding portion 192 a of the folding blade 192 is a portion that is heated by a heater connected to the inside of the folding blade 192 .

[0163] The heating portion of the folding blade 192 may not be a partial heating portion, but the entire folding blade 192 may be a heating component.

[0164] [Variation 10] Next, a saddle stitching processing unit according to Modification 10 will be described with reference to Fig. 27. The difference from the saddle stitching processing unit according to Modification 8 is that the folding blade engaging member is not a roller member that scans (rotates), but is configured as a folding blade engaging die 193 as a blade member that extends in the width direction. Note that components common to the saddle stitching processing unit according to the first embodiment are given the same reference numerals, and detailed description thereof will be omitted.

[0165] Figure 27 is a cross-sectional view showing the operation of Variant 9 of the saddle stitching processing unit. It is a cross-sectional view of the center line of the center fold. In other words, it is a cross-sectional view taken along the line BB as seen from the paper transport direction side at the center position of the thickness of the folding blade 132. Figure 27(a) corresponds to the state of Figure 6(c). The folding blade 132 has pushed the paper stack Pb to a position beyond the nip position of the pair of folding rollers 133, and the folding blade engagement die 193 is in the standby position (HP position) and is spaced apart from the paper stack Pb in the center fold discharge direction.

[0166] The folding blade engaging die 193 is moved toward the folding blade 132 by a folding blade engaging die moving motor 182 (not shown).

[0167] Fig. 27(b) corresponds to the state of Fig. 6(d). The folding blade engagement die 193 is pressed against the folding blade 132 with the paper-sheet bundle Pb sandwiched therebetween, and the heat and pressure bonding portion 192a of the folding blade engagement roller 191 is pressed against the pushing surface of the folding blade 132, and the paper-sheet bundle Pb is heated and pressurized with the paper-sheet bundle Pb sandwiched therebetween, whereby the spine of the paper-sheet bundle Pb is pressure-bound.

[0168] [Second embodiment] Next, a second embodiment of the image forming system according to the present invention will be described. Fig. 21 is a diagram showing the overall configuration of an MFP 200 as the second embodiment of the image forming system. The MFP 200 has the function of forming an image on a sheet P (medium) and performing post-processing on the sheet P on which the image has been formed. As shown in Fig. 21, the MFP 200 is made up of an image forming device 201 and a console-type post-processing device 210 arranged adjacent to the image forming device.

[0169] The image forming device 201 forms an image on a sheet P and discharges the sheet P with the image formed thereon to the post-processing device 210. The image forming device 201 includes a tray for storing the sheet P, a transport unit for transporting the sheet P stored in the tray, and an image forming unit for forming an image on the sheet P transported by the transport unit. The image forming unit may be of an inkjet type that forms an image using ink, or of an electrophotographic type that forms an image using toner. The configuration of the image forming device 201 is already well known, so a detailed description thereof will be omitted.

[0170] FIG. 22 is a diagram showing the internal structure of a post-processing device 210 according to the second embodiment. The post-processing device 210 performs post-processing on sheets P on which images have been formed by the image forming device 201. The post-processing according to this embodiment is a binding process that binds a stack of multiple sheets P on which images have been formed (hereinafter referred to as a "sheet stack Pb"). More specifically, the binding process according to this embodiment includes so-called "pressure binding" in which the sheet stack Pb is pressurized and deformed at a press binding position, and "staple binding" in which the sheet stack Pb is bound with staples. Furthermore, press binding includes an end binding process that binds the ends of the sheet stack Pb, and a saddle binding process that binds the center of the sheet stack Pb.

[0171] Components common to the saddle stitching processing unit according to the first embodiment are given the same reference numerals, and detailed description thereof will be omitted.

[0172] [Saddle Stitch Processing] As shown in FIG. 22, the post-processing device 210 includes a folding blade 232 , a pair of folding rollers 233 , a folding blade engaging roller 234 , a pair of half-folded booklet discharge rollers 235 , and a half-folded booklet discharge tray 236 .

[0173] The conveying rollers switch back and convey the paper P toward the movable end fence 238 while placing the paper P on the saddle stitching inner tray 237.

[0174] The saddle stitching internal tray 237 temporarily holds multiple sheets of paper P that are transported in sequence. The movable end fence 238 is movable along the saddle stitching internal tray 237 in the transport direction of the sheets of paper P, and aligns the position of the sheets so that the folding blade 232 faces the center position of the length in the paper transport direction according to the sheet size. The side fences align the position in the main scanning direction (width direction) of the sheets of paper P or the sheet stack Pb placed on the saddle stitching internal tray 237. The saddle stitching processing unit saddle stitches the sheet stack Pb aligned by the movable end fence 238 and the side fences. The saddle stitched sheet stack Pb is discharged by a pair of center-folded booklet discharge rollers 235 and stacked on a center-folded booklet discharge tray 236.

[0175] According to the present embodiment described above, the center-folding process, square-folding process, and saddle-stitching process can be performed simultaneously in parallel. In the prior art, the center-folding process is performed after the saddle-stitching process, so the present embodiment can improve the efficiency of the booklet formation process compared to the prior art.

[0176] Furthermore, according to this embodiment, the spine of the booklet can be folded in a square shape (U-shaped folding) and the spine of the booklet can be crimp-bound.

[0177] Furthermore, according to this embodiment, the folding blade is provided with a flange for folding the spine of the booklet into a square, which makes it possible to achieve a square fold with a clearer crease.

[0178] The present invention is not limited to the above-described exemplary embodiments, and various modifications are possible without departing from the technical gist thereof. The present invention covers all technical matters included in the technical concept described in the claims. The above-described embodiments are preferred examples, but a person skilled in the art can realize various modifications from the disclosed content. Such modifications are also included in the technical scope described in the claims.

[0179] For example, aspects of the present invention are as follows. <1> a center folding unit for performing center folding on a sheet bundle made up of a plurality of sheet materials; a pressure binding means for pressure binding the sheet bundle that has been subjected to the center-folding process; Equipped with The pressure binding means is a spine forming processing section for forming a spine on the sheet bundle that has been subjected to the center-folding processing; a pressure binding processing unit that performs the pressure binding process on the sheet bundle that has been subjected to the center folding process; and The back forming processing unit includes: a folding plate member having protrusions at both ends in a plate thickness direction on a pushing surface of the sheet stack; a folding plate engaging member that engages with the folding plate member via the sheet bundle; Equipped with The sheet processing apparatus is characterized by the above. <2> The center folding means is The folding plate member; a pair of folding rollers that sandwich the sheet stack that has been guided by the folding plate member and pushed out in a predetermined direction while advancing the sheet stack in the direction; Equipped with The aforementioned <1> 2. The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is a sheet processing apparatus. <3> the folding plate engagement member is biased toward the folding plate member; The spine is sandwiched between the folding plate member and pressed. The aforementioned <1> or the above <2> 2. The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is a sheet processing apparatus. <4> The folding plate engaging member is a roller-shaped member supported by a journal, a spine forming process for forming a spine in the sheet bundle by reciprocating in the longitudinal direction of the spine and a pressure binding process; The aforementioned <1> and above <3> 10. The sheet processing apparatus according to claim 9, wherein the sheet is a sheet having a thickness of 100 μm or less. <5> the folding plate member has a folding plate pressing tooth having a concave-convex shape on a surface facing the folding plate engaging member, The folding plate engaging member has engagement crimping teeth having a concave-convex shape that engage with the folding plate crimping teeth. The aforementioned <1> and above <4> 10. The sheet processing apparatus according to claim 9, wherein the sheet processing apparatus is a sheet processing apparatus having a plurality of nozzles. <6> the folding plate engaging member simultaneously performs a spine forming process for forming a spine in the sheet bundle and the pressure binding process by moving the spine in the longitudinal direction; The aforementioned <1> and above <5> 10. The sheet processing apparatus according to claim 9, wherein the sheet processing apparatus is a sheet processing apparatus having a plurality of nozzles. <7> The folding plate member has a plurality of spaced apart, concave-convex folding plate pressing teeth on a surface facing the folding plate engaging member, the folding plate engaging member has a plurality of spaced apart engaging crimping teeth having a concave-convex shape that engage with the folding plate crimping teeth, The crimp binding process is performed by moving the folding plate member toward the folding plate engaging member. The aforementioned <1> and above <6> 10. The sheet processing apparatus according to claim 9, wherein the sheet processing apparatus is a sheet processing apparatus having a plurality of nozzles. <8> The folding plate engaging member is a plate-shaped blade member that faces the folding plate member, and the pressure binding process is performed by moving the blade member toward the folding plate member. The aforementioned <1> and above <7> 10. The sheet processing apparatus according to claim 9, wherein the sheet processing apparatus is a sheet processing apparatus having a plurality of nozzles. <9> The pressure binding processing unit includes: a first roller member having concave and convex teeth; a second roller member that engages with the first roller member via the sheet stack; It consists of The aforementioned <1> and above <8> 10. The sheet processing apparatus according to claim 9, wherein the sheet processing apparatus is a sheet processing apparatus having a plurality of nozzles. <10> The protrusion of the folding plate member is engaged across the opposing surface of the folding plate engaging member. The aforementioned <1> and above <9> 10. The sheet processing apparatus according to claim 9, wherein the sheet processing apparatus is a sheet processing apparatus having a plurality of nozzles. <11> the engaging and crimping teeth have a repeated concave and convex shape in the main scanning direction of the sheet stack; The aforementioned <5> 2. The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is a sheet processing apparatus. <12> the engaging and crimping teeth have a repeated uneven shape inclined in the main scanning direction of the sheet stack; The aforementioned <5> 2. The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is a sheet processing apparatus. <13> the folding plate member has a surface facing the folding plate engaging member, the surface having a plurality of concave-convex shaped folding plate pressing teeth at a plurality of positions, and the surface other than the portions where the concave-convex shaped folding plate pressing teeth are formed is flat. The aforementioned <5> 2. The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is a sheet processing apparatus. <14> The pressure binding means is The folding plate member; a folding plate engaging and heating member that presses the sheet stack toward the folding plate member and includes a heating portion that heats the sheet stack; Equipped with The folding plate engagement heating member heats an adhesive medium formed in the adhesive portion of the sheet stack. The aforementioned <1> and above <13> 10. The sheet processing apparatus according to claim 9, wherein the sheet processing apparatus is a sheet processing apparatus having a plurality of nozzles. <15> The pressure binding means is the folding plate member including a heating unit that heats the sheet stack; The folding plate engaging heating member; Equipped with The folding plate engagement heating member heats an adhesive medium formed in the adhesive portion of the sheet stack. The aforementioned <14> 2. The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is a sheet processing apparatus. <16> An image forming system including an image forming apparatus and a sheet processing apparatus that performs a predetermined process on a sheet material on which an image has been formed by the image forming apparatus, the adhesive medium is formed by the image forming device; The sheet processing device <14> or the above <15> The sheet processing apparatus according to claim 1, The image forming system is characterized by the above. <17> The adhesive medium is a toner that forms a visible image. The aforementioned <16> 2. The image forming system according to claim 1, wherein: <18> An image forming system including an image forming apparatus and a sheet processing apparatus that performs a predetermined process on a sheet material on which an image has been formed by the image forming apparatus, The sheet processing device <1> The sheet processing apparatus according to claim 1, The image forming system is characterized by the above. <19> A sheet processing method that can be performed in a sheet processing apparatus that includes a center folding unit that performs a center folding process on a sheet bundle made up of a plurality of stacked sheet materials, and a pressure binding unit that performs a pressure binding process on the sheet bundle that has been center folded, wherein the pressure binding unit: a spine forming process for forming a spine along the fold formed in the sheet bundle; a spine crimp binding process for performing the crimp binding process on the spine; The sheet processing method is characterized by carrying out the following steps. [Explanation of symbols]

[0180] 100:MFP 101: Image forming device 102: Operation panel 110: Post-processing device 117: Staple binding processing section 118: Pressure binding processing section 119: Discharge roller pair 120: Discharge tray 131: Movable end fence 132: Folding blade 132a: Folding blade crimping teeth 132b: flange part 132c: Pressure roller rail 133: Pair of folding rollers 134: Folding blade engaging roller 134a: Engagement crimp teeth 135: Pair of center-folded booklet discharge rollers 136: Center-folded booklet ejection tray 141: Folding blade movement motor 142: Folding roller pair rotation motor 143: Folding roller pair contact / separation motor 144: Folding roller pair pressure member 145: Folding blade engagement roller scanning motor 146: Engagement roller guide rail 146a: Engagement roller guide rail 147: Folding blade engaging roller pressure member 177: Upper crimping teeth 178: Lower crimping teeth 181: Folding blade engagement die 181a: Die crimping part 182: Folding blade engagement die moving motor 183: Folding blade engagement die pressure member 184: Folding blade 184a: Concave and Convex Teeth 185: Folding blade engagement die 185a: Crimping part 186: Folding blade engagement die 186a: Crimping part 187: Pressure roller 187a: Concave and Convex Teeth 188: Pressure roller movement motor 190: Controller 191: Folding blade engaging roller 191a: Heat pressing section 191b: Flange part 192: Folding blade 192a: Heat pressing section 192b: Flange part 193: Folding blade engagement die [Prior art documents] [Patent documents]

[0181] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-031268 [Patent Document 2] Patent No. 6089675 [Patent Document 3] Japanese Patent Application Laid-Open No. 2004-168012 [Patent Document 4] Patent No. 5361858

Claims

1. a center folding unit for performing center folding on a sheet bundle made up of a plurality of sheet materials; a pressure binding means for pressure binding the sheet bundle that has been subjected to the center-folding process; Equipped with The pressure binding means is a spine forming processing section for forming a spine on the sheet bundle that has been subjected to the center-folding processing; a pressure binding processing unit that performs the pressure binding process on the sheet bundle that has been subjected to the center folding process; and The back forming processing unit includes: a folding plate member having protrusions at both ends in a plate thickness direction on a pushing surface of the sheet stack; a folding plate engaging member that engages with the folding plate member via the sheet bundle; Equipped with A sheet processing apparatus characterized by:

2. The center folding means is The folding plate member; a pair of folding rollers that sandwich the sheet stack that has been guided by the folding plate member and pushed out in a predetermined direction while advancing the sheet stack in the direction; Equipped with The sheet processing apparatus according to claim 1 .

3. the folding plate engagement member is biased toward the folding plate member; The spine is sandwiched between the folding plate member and pressed. The sheet processing apparatus according to claim 1 .

4. The folding plate engaging member is a roller-shaped member supported by a journal, a spine forming process for forming a spine in the sheet bundle by reciprocating in the longitudinal direction of the spine and a pressure binding process; The sheet processing apparatus according to claim 1 .

5. the folding plate member has a folding plate pressing tooth having a concave-convex shape on a surface facing the folding plate engaging member, The folding plate engaging member has engagement crimping teeth having a concave-convex shape that engage with the folding plate crimping teeth. The sheet processing apparatus according to claim 1 .

6. the folding plate engaging member simultaneously performs a spine forming process for forming a spine in the sheet bundle and the pressure binding process by moving the spine in the longitudinal direction; The sheet processing apparatus according to claim 1 .

7. The folding plate member has a plurality of spaced apart, concave-convex folding plate pressing teeth on a surface facing the folding plate engaging member, the folding plate engaging member has a plurality of spaced apart engaging crimping teeth having a concave-convex shape that engage with the folding plate crimping teeth, The crimp binding process is performed by moving the folding plate member toward the folding plate engaging member. The sheet processing apparatus according to claim 1 .

8. The folding plate engaging member is a plate-shaped blade member that faces the folding plate member, and the pressure binding process is performed by moving the blade member toward the folding plate member. The sheet processing apparatus according to claim 1 .

9. The pressure binding processing unit includes: a first roller member having uneven teeth; a second roller member that engages with the first roller member via the sheet stack; It consists of The sheet processing apparatus according to claim 1 .

10. The protrusion of the folding plate member is engaged across the opposing surface of the folding plate engaging member. The sheet processing apparatus according to claim 1 .

11. the engaging and crimping teeth have a repeated concave and convex shape in the main scanning direction of the sheet stack; The sheet processing apparatus according to claim 5 .

12. the engaging and crimping teeth have a repeated uneven shape inclined in the main scanning direction of the sheet stack; The sheet processing apparatus according to claim 5 .

13. the folding plate member has a surface facing the folding plate engaging member, the surface having a plurality of concave-convex shaped folding plate pressing teeth at a plurality of positions, and the surface other than the portions where the concave-convex shaped folding plate pressing teeth are formed is flat. The sheet processing apparatus according to claim 5 .

14. The pressure binding means is The folding plate member; a folding plate engaging and heating member that presses the sheet stack toward the folding plate member and includes a heating portion that heats the sheet stack; Equipped with The folding plate engagement heating member heats an adhesive medium formed in the adhesive portion of the sheet stack. The sheet processing apparatus according to claim 1 .

15. The pressure binding means is the folding plate member including a heating unit that heats the sheet stack; The folding plate engaging heating member; Equipped with The folding plate engagement heating member heats an adhesive medium formed in the adhesive portion of the sheet stack. The sheet processing apparatus according to claim 14 .

16. An image forming system including an image forming apparatus and a sheet processing apparatus that performs a predetermined process on a sheet material on which an image has been formed by the image forming apparatus, the adhesive medium is formed by the image forming device; The sheet processing apparatus is the sheet processing apparatus according to claim 14 or 15. An image forming system comprising:

17. The adhesive medium is a toner that forms a visible image. The imaging system of claim 16.

18. An image forming system including an image forming apparatus and a sheet processing apparatus that performs a predetermined process on a sheet material on which an image has been formed by the image forming apparatus, The sheet processing apparatus is the sheet processing apparatus according to claim 1. An image forming system comprising:

19. A sheet processing method that can be performed in a sheet processing apparatus that includes a center folding unit that performs a center folding process on a sheet bundle made up of a plurality of stacked sheet materials, and a pressure binding unit that performs a pressure binding process on the sheet bundle that has been center folded, wherein the pressure binding unit: a spine forming process for forming a spine along the fold formed in the sheet bundle; a spine crimp binding process for performing the crimp binding process on the spine; A sheet processing method comprising the steps of:

Images