Post-processing device

Abstract

To provide a post-processing device that improves productivity when performing post-processing on sheets ejected from an image forming device, and eliminates misalignment of the sheets.SOLUTION: A post-processing device comprises a shift mechanism that shifts at least one of a first transportation roller and a second transportation roller. Shift operations by the shift mechanism comprise a first shift operation performed on the first transportation roller and a second shift operation performed on the second transportation roller, and the shift operations eliminate misalignment detected by a detection unit for the first sheet and the second sheet.SELECTED DRAWING: Figure 34

Description

[Technical field]

[0001] The present invention relates to a post-processing device capable of performing post-processing on a sheet on which an image has been formed. [Background technology]

[0002] A sheet post-processing device is known as a device that is connected to the sheet discharge port of an image forming device, temporarily holds image-formed sheets in the conveying path or on a tray, performs post-processing on the sheets, and then stores the sheets in a storage stacker. Examples of post-processing include punching holes in the sheets, accumulating and binding the sheets, folding the sheets, and the like.

[0003] Also, a jog mechanism is known that stores and separates sheets in a stacker by changing the position of the sheet discharge perpendicular direction. This jog mechanism is known to be realized by a mechanism that performs an operation of shifting the sheet by a predetermined amount in the perpendicular direction to the conveyance (hereinafter referred to as "offset movement") in the conveyance path or on a tray that is temporarily placed on the sheet.

[0004] Patent document 1 describes a configuration in which a sheet is received from a main body paper discharge port 3 of an image forming device A and transported to a second accumulation section 35 via a second switchback transport path SP2 branched off from a sheet input path P1.

[0005] Patent Document 2 describes a branch path 34 that guides the sheet to a second post-processing section 49. Also, the document describes a configuration in which a path buffer section Pb is provided in the straight path 33 and the branch path 34 to temporarily store the sheet. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2008-213971 A [Patent Document 2] JP 2015-209278 A Summary of the Invention [Problem to be solved by the invention]

[0007] It is required to improve the productivity of post-processing in a configuration that allows the post-processing section to receive subsequent sheets while the post-processing section is performing post-processing on the preceding sheet bundle in the post-processing section. In addition, since the sheets discharged from the image forming apparatus generally have a positional deviation, it is necessary to provide a configuration that eliminates the deviation.

[0008] SUMMARY OF THE DISCLOSURE An object of the present invention is to provide a post-processing device that improves productivity when post-processing is performed on sheets discharged from an image forming apparatus and eliminates positional deviation of the sheets. [Means for solving the problem]

[0009] In order to solve the above problems, a post-processing device according to the present invention includes a receiving section that receives a sheet, a detection section that detects a deviation of the sheet received by the receiving section in a direction perpendicular to a conveying direction, a first conveying roller that conveys the sheet received by the receiving section, a guide section that forms a conveying path together with the first conveying roller and is configured to be able to switch the conveying path of the sheet, a stacking section that is provided on one side of the conveying path and receives and stacks a sheet conveyed in reverse by the reverse operation of the first conveying roller via the guide section from the rear end of the sheet, a post-processing section that performs post-processing on the sheet stack stacked in the stacking section, and a post-processing section that is provided on the other side of the conveying path and, when a preceding sheet stack is present in the stacking section, receives a sheet conveyed in reverse by the reverse operation of the first conveying roller via the guide section from the rear end of the sheet, the first conveying roller overlaps a first sheet conveyed by the second conveying roller from the evacuation path with a second sheet received by the receiving section, and conveys the sheet to the stacking section by a reverse rotation of the first conveying roller, and the shift operation by the shift mechanism includes a first shift operation performed on the first conveying roller and a second shift operation performed on the second conveying roller, and the shift operation eliminates the misalignment of the first sheet and the second sheet detected by the detection section by the shift operation. Effect of the Invention

[0010] According to the present invention, it is possible to further improve the productivity when performing post-processing on a sheet discharged from an image forming apparatus, and to eliminate positional deviation of the sheet. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram illustrating an external appearance of an image forming system. [Diagram 2] FIG. 2 is a diagram illustrating a configuration of a sheet post-processing device. [Diagram 3] FIG. 13 is a diagram showing a configuration in the vicinity of a straight path. [Figure 4] FIG. 2 is a diagram showing a configuration of a punch unit. [Diagram 5] FIG. 2 is a diagram showing a configuration of a punch unit. [Figure 6] 11A and 11B are diagrams illustrating a shift mechanism of a conveying roller. [Figure 7] 11A and 11B are diagrams illustrating a shift mechanism of a conveying roller. [Figure 8] FIG. 13 is a diagram for explaining a binding mechanism. [Figure 9] FIG. 13 is a diagram for explaining a binding mechanism. [Figure 10] FIG. 13 is a diagram for explaining a binding mechanism. [Figure 11] 11A and 11B are diagrams for explaining a tray lifting mechanism. [Figure 12] 11A and 11B are diagrams for explaining a sheet discharge mechanism. [Figure 13] FIG. 2 is a diagram showing a configuration of a staple unit. [Figure 14] FIG. 2 is a diagram showing the configuration around a control unit. [Figure 15] 13 is a flowchart showing a process in a bookbinding process paper discharge mode. [Figure 16] 10A and 10B are diagrams for explaining a sheet buffer operation in the sheet processing apparatus; [Figure 17] 10A and 10B are diagrams for explaining a sheet buffer operation in the sheet processing apparatus; [Figure 18] 10A and 10B are diagrams for explaining a sheet buffer operation in the sheet processing apparatus; [Figure 19] 10A and 10B are diagrams for explaining a sheet buffer operation in the sheet processing apparatus; [Figure 20] 10A and 10B are diagrams for explaining a sheet buffer operation in the sheet processing apparatus; [Figure 21] 10A and 10B are diagrams for explaining a sheet buffer operation in the sheet processing apparatus; [Figure 22] 10A and 10B are diagrams for explaining a sheet buffer operation in the sheet processing apparatus; [Figure 23] 10A and 10B are diagrams for explaining a sheet buffer operation in the sheet processing apparatus; [Figure 24] 11A and 11B are diagrams for explaining lateral registration adjustment. [Diagram 25] 11A and 11B are diagrams for explaining lateral registration adjustment. [Figure 26] 11A and 11B are diagrams for explaining lateral registration adjustment. [Figure 27] 11A and 11B are diagrams for explaining lateral registration adjustment. [Figure 28] 11A and 11B are diagrams for explaining lateral registration adjustment. [Figure 29] 11A and 11B are diagrams for explaining lateral registration adjustment. [Diagram 30] 11A and 11B are diagrams for explaining lateral registration adjustment. [Diagram 31] 11A and 11B are diagrams for explaining lateral registration adjustment. [Diagram 32] 11A and 11B are diagrams for explaining lateral registration adjustment. [Diagram 33] 11A and 11B are diagrams for explaining lateral registration adjustment. [Diagram 34] 13 is a flowchart showing a sheet buffer operation. [Diagram 35] 13 is a flowchart showing a sheet buffer operation. [Diagram 36] 13A and 13B are diagrams for explaining the operation in the case of a large-sized sheet. [Figure 37] 13A and 13B are diagrams for explaining the operation in the case of a large-sized sheet. [Figure 38] 13A and 13B are diagrams for explaining the operation in the case of a large-sized sheet. [Figure 39] 13A and 13B are diagrams for explaining the operation in the case of a large-sized sheet. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, the embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0013] [Image forming equipment] An image forming apparatus A in the image forming system shown in Fig. 1 will be described. The image forming apparatus A shown in the figure shows an electrostatic printing mechanism, and is configured to include an image forming unit A1, a scanner unit A2, and a feeder unit A3. An apparatus housing 1 is provided with mounting legs 25 for installation on an installation surface (e.g., a floor surface). Inside the apparatus housing 1, a paper feed section 2, an image forming section 3, a paper discharge section 4, and a data processing section 5 are built in.

[0014] The paper feed unit 2 includes cassette mechanisms 2a-2c that store sheets of multiple sizes on which images are to be formed, and feeds sheets of a size specified by the main body control unit 90 to a paper feed path 6. For this purpose, multiple cassettes 2a-2c are detachably arranged in the device housing 1, and each cassette incorporates a separation mechanism that separates the sheets inside one by one, and a paper feed mechanism that feeds out the sheets. The paper feed path 6 is provided with a transport roller 7 that feeds the sheets supplied from the multiple cassettes 2a-2c downstream, and a registration roller pair 8 that aligns the leading edges of each sheet is provided at the end of the path.

[0015] In addition, a large-capacity cassette 2d and a manual feed tray 2e are connected to the paper feed path 6, and the large-capacity cassette 2d is configured to include an optional unit for storing sheets of a size that is consumed in large quantities, and the manual feed tray 2e is configured to be able to supply special sheets such as cardboard sheets, coated sheets, and film sheets that are difficult to separate and feed.

[0016] The image forming unit 3 is shown as an example of an electrostatic printing mechanism, and includes a photoconductor 9 (drum, belt), a light emitter 10 that emits an optical beam to the photoconductor 9, a developer 11, and a cleaner (not shown) that are arranged around the rotating photoconductor. The illustrated one shows a monochrome printing mechanism, in which a latent image is optically formed on the photoconductor drum 9 by the light emitter 10, and toner ink is applied to the latent image by the developer 11. Then, a sheet is sent from the paper feed path 6 to the image forming unit 3 in accordance with the timing of image formation on the photoconductor 9, an image is transferred onto the sheet by a transfer charger 12, and the image is fixed by a fixing unit (roller) 13 arranged on a paper discharge path 14. A paper discharge roller 15 and a paper discharge port 16 are arranged on the paper discharge path 14, and the sheet is transported to a sheet post-processing device B described later.

[0017] Scanner unit A2 includes a platen 17 on which an image original is placed, a carriage 18 that moves back and forth along the platen 17, a light source mounted on carriage 18, and a reduction optical system 20 (a combination of mirrors and lenses) that guides reflected light from the original on platen 17 to photoelectric conversion unit 19. Reference numeral 21 in the figure denotes a second platen (traveling platen), which reads an image on a sheet sent from feeder unit A3 by means of carriage 18 and reduction optical system 20. Photoelectric conversion unit 19 transfers the photoelectrically converted image data to image forming unit 3.

[0018] The feeder unit A3 includes a paper feed tray 22, a paper feed path 23 that guides sheets fed from the paper feed tray to a traveling platen 21, and a paper discharge tray 24 that stores documents whose images have been read by the platen.

[0019] The image forming apparatus A is not limited to the above mechanism, and may employ printing mechanisms such as an offset printing mechanism, an inkjet printing mechanism, and an ink ribbon transfer printing mechanism (thermal transfer ribbon printing, dye-sublimation ribbon printing, etc.).

[0020] [Sheet post-processing device] The sheet post-processing device B is a device for post-processing sheets discharged from the sheet discharge port 16 of the image forming device A and has, for example, (1) a function for stacking and storing image-formed sheets (printout mode), (2) a function for storing image-formed sheets in portions (jog sorting mode), (3) a function for collating and stacking image-formed sheets and binding them (binding processing mode), and (4) a function for collating and binding the image-formed sheets, folding them, and finishing them into books (binding processing mode).

[0021] In this embodiment, the sheet post-processing device B does not need to have all the above functions, and is configured appropriately according to the device specifications (design specifications). As an example, this embodiment is assumed to have a function of folding and bookbinding the sheets on which images are formed after collating and binding them.

[0022] FIG. 2 shows the configuration of the sheet post-processing device B, and FIG. 3 shows the configuration around the straight path 28. The sheet post-processing device B processes the sheets carried in from the straight path entrance 26 connected to the paper discharge port 16 of the image forming device A, and then stores the sheets in a storage section (a first stack tray 49, a second stack tray 61, and a third stack tray 71 described below). The illustrated device transfers the sheets sent to the straight path 28 from a processing section B1 including a binding unit 47 to a first stack tray 49 (hereinafter referred to as the "first tray") and a third stack tray 71 (hereinafter referred to as the "third tray"). Also, the sheet sent to the straight path 28 is transferred from a saddle section B2 to a second stack tray 61 (hereinafter referred to as the "second tray"). The straight path 28 is formed in a substantially straight line, so that even thick paper can be transported.

[0023] The processing section B1 is disposed at the path exit (straight path paper discharge port 35) of the straight path 28, and collates and stacks the sheets fed in sequence, performs a stapling process, and stores them in the first tray 49. The saddle section B2 is disposed at the path exit (saddle path paper discharge port) of the saddle path 32 branching off from the straight path 28, and is a post-processing section that collates and stacks the sheets fed in sequence, saddle-staples them (they may not be saddle-stapled), folds them, and stores them in the second tray 61. Each component will be described in detail below.

[0024] <Device housing> 2, the sheet post-processing device B includes a device housing 27, a straight path 28 that is built into the device housing and has a straight path inlet 26 and a straight path paper discharge outlet 35, a processing section B1 and a saddle section B2 that process sheets fed from the straight path 28, and a first tray 49, a second tray 61, and a third tray 71 that store sheets fed from each processing section. The illustrated device housing 27 is disposed at approximately the same height as the housing 1 of the image forming device A located upstream, and the paper discharge outlet 16 of the image forming device A and the straight path inlet 26 of the sheet post-processing device B are connected on the installation surface.

[0025] The housing 27 of the sheet post-processing device is configured to include a device frame 70. The device frame 70 forms the framework of a box-shaped device as shown in FIG. 6, and includes a front side frame 70f located at the front in the state of FIG. 1, a rear side frame 70r located at the back, and a stay member (connecting reinforcement member) connecting the two side frames. The straight path 28, the processing section B1, the saddle section B2, etc., which will be described later, are attached between the left and right side frames. The device housing 27 is not limited to the shape shown in the figure, and may have a shape suitable for design, and the device frame 70 is not limited to a structure of left and right side frames and connecting stays, and various frame structures such as a monocoque structure can be adopted.

[0026] <Sheet delivery route> 3, the straight path 28 is formed of a substantially linear path that crosses the device housing 27 in a substantially horizontal direction, and includes a straight path entrance 26 that is connected to the paper exit (main body paper exit) 16 of the image forming device A, and a straight path paper exit 35 that is located on the opposite side of the entrance (straight path entrance 26) across the device. In the straight path 28, an entrance roller 29, a first conveying roller 201, a second conveying roller 202, and a third conveying roller 203 are arranged in this order from the straight path entrance 26 side as a conveying mechanism that can convey a sheet from the straight path entrance 26 to the straight path paper exit 35 and can convey from the straight path paper exit 35 to the straight path entrance 26. In addition, a paper exit roller 36 (including a sheet conveying mechanism such as a belt) is arranged at the straight path paper exit 35 as a conveying mechanism. In addition, an entrance sensor S1 that detects the leading and trailing ends of the received sheet and a lateral registration detection sensor S0 (detection unit) that detects the end face position (side edge) parallel to the conveying direction of the sheet are arranged near the straight path entrance 26. In addition, a discharge sensor S2 that detects the leading and trailing ends of the sheet is arranged near the straight path discharge outlet 35. The sheet discharged from the straight path discharge outlet 35 is discharged to the first tray 49 via the first discharge path 31 connected to the straight path discharge outlet 35, or is guided to the processing unit B1. In addition, a punch unit 100 that punches holes in the sheet is arranged in the straight path 28.

[0027] <Sheet delivery route layout> In the straight path 28, as shown in FIG. 2 and FIG. 3, the "saddle path 32", the "saddle buffer path P2", the "processing buffer path P1", and the "upper conveying path 30" are arranged in this order from the straight path entrance 26 toward the straight path paper discharge port 35, and at the branching points of each of the above paths, the saddle path flapper 33b, the saddle buffer path flapper 33a, the processing buffer path flapper 200, and the upper conveying path flapper 34 are arranged as a conveying switching mechanism (branching mechanism) for the conveyed sheet. In this embodiment, the saddle buffer path P2 and the upper conveying path 30 are configured as an evacuation path for evacuating the sheet. In addition, as shown in FIG. 2, the saddle part B2 is provided on one side of the straight path 28, and the saddle buffer path P2 and the upper conveying path 30 are provided on the opposite side (the other side). This can further improve the conveying efficiency of the sheet located in the evacuation path to the saddle part B2.

[0028] Among the above paths, the saddle path 32, the saddle buffer path P2, and the processing section buffer path P1 are configured as switchback paths that transport the sheet in the opposite direction to the transport direction from the straight path entrance 26 to the straight path paper discharge outlet 35 and introduce the sheet into each of the above paths. In addition, the upper transport path 30 is configured to transport the sheet in the same direction as the transport direction from the straight path entrance 26 to the straight path paper discharge outlet 35.

[0029] <Path branching mechanism> The saddle path flapper 33b, saddle buffer path flapper 33a, and processing section buffer path flapper 200, which are the above-mentioned sheet branching mechanisms, are composed of flapper guides that are movable so as to be able to switch the conveying path of the sheet carried in from the straight path entrance 26, and are connected to a driving mechanism (not shown) such as an electromagnetic solenoid or a mini motor. The above-mentioned saddle path flapper 33b guides the sheet sent from the straight path entrance 26 to the saddle path 32. The saddle buffer flapper 33a guides the sheet sent from the straight path entrance 26 to the saddle buffer path P2. The processing section buffer flapper 200 guides the sheet sent from the straight path entrance 26 to the processing section buffer path P1 via the processing section buffer rollers 301a and 301b. The upper conveying path flapper 34 includes a movable flapper guide that switches the conveying path so that the sheet fed from the straight path inlet 26 is conveyed to either the straight path paper discharge outlet 35 or the upper conveying path 30, and is connected to a drive mechanism (not shown) such as an electromagnetic solenoid or a mini motor.

[0030] <Upper transport path> An upper conveying path 30 (printout paper discharge path) that carries in sheets other than those to be discharged to the straight path paper discharge port 35 is connected to the straight path 28, and an upper conveying path flapper 34 for guiding sheets to the upper conveying path 30 is provided at the path branching portion. The upper conveying path 30 is also provided with upper conveying rollers 303 (303a, 303b) that guide the sheets to the third tray 71. As a result, the sheets guided to the upper conveying path 30 are discharged from the upper conveying path paper discharge port 40 to the third tray 71 (overflow tray). In this embodiment, the upper conveying path 30 is also used as a sheet evacuation path.

[0031] <Saddle Pass> A saddle path 32 for conveying the sheet to the saddle section B2 is connected to the straight path 28, and a path branching section is provided with a saddle path flapper 33b for guiding the sheet to the saddle path 32. The sheet guided from the saddle path 32 to the saddle section B2 via the saddle path paper discharge port is saddle-stitched and folded, and then discharged to the second tray 61 via the substantially horizontal saddle discharge path 68.

[0032] <Saddle buffer path> A saddle buffer path P2 for temporarily carrying in and waiting for sheets to be saddle-stitched and folded in the saddle section B2 is connected to the straight path 28, and a saddle buffer path flapper 33a for guiding the sheets to the saddle buffer path P2 is provided. The saddle buffer path P2 is also provided with conveying rollers 302 (302a, 302b) for carrying in the sheets and temporarily waiting for them.

[0033] A fourth tray discharge port 305 is provided on the downstream extension of the saddle buffer path P2, so that the sheets carried into the saddle buffer path P2 can be discharged and stacked on the fourth tray 310. In this case, the fourth tray 310 is disposed vertically above the saddle buffer path P2. The fourth tray 310 may be shared with an exterior component on the top surface of the sheet post-processing device B, may be fixed to the device housing, or may be provided with a drive mechanism and configured to be liftable and lowerable in a substantially vertical direction.

[0034] The device can be made more compact by arranging the saddle buffer path P2 in an overlapping position vertically above the punch unit 100. However, if space is required to flip the punch unit 100 upward to remove sheets retained in the punch unit 100, the saddle buffer path P2 may be arranged in a non-overlapping position vertically above the punch unit 100.

[0035] <Transport roller shift mechanism in the loading path> Here, the conveyance shift mechanism provided in the conveyance rollers on the conveyance path will be described with reference to Figs. 6 and 7. The first conveyance roller 201, the second conveyance roller 202, the third conveyance roller 203, and the conveyance rollers 302a and 302b are each configured to include a drive roller 111 and a driven roller 112 rotatably supported by bearings on the left and right side frames 70f and 70r. A drive rotation shaft is connected to the drive roller shaft 113 by a transmission mechanism 116 (the illustrated one is a gear transmission), and a drive motor (not shown) common to the paper discharge roller 36 is connected to the drive rotation shaft 115. The driven roller shaft 114 is supported by bearings on the left and right side frames 70f and 70r so as to be free to move.

[0036] Each of the above-mentioned conveying rollers is rotatably attached to a shift member 117 that connects the driving roller shaft 113 and the driven roller shaft 114. The shift member 117 connects the driving roller shaft 113 and the driven roller shaft 114 so that they move integrally in the axial direction (thrust direction) and can rotate independently in the radial direction. The driving roller shaft 113 is supported by bearings on the left and right side frames 70f and 70r, with one end of the driving roller shaft 113 located in a range indicated by the axial movement region of the conveying roller on the front side of the side frame 70f and the other end located on the rear side of the side frame 70r, and the shift member 117 (e.g., a block member made of synthetic resin) supported by the driving roller shaft 113 and the driven roller shaft 114 to integrally connect both roller shafts.

[0037] A rack 117a is formed integrally with the shift member 117, and is engaged with a shift motor M9 and a transmission pinion 117b attached to the side frame 70r (device frame; the same applies below). With this configuration, the shift member 117 can be moved (shifted) in the axial direction of the conveying roller by rotating the shift motor M9 (the illustrated one is a stepping motor that can rotate forward and backward).

[0038] A driven gear 118 is formed integrally with the driving rotation shaft 115, and the rotation of the driving motor is transmitted to the driven gear 118. In addition, a pair of conveying rollers (a driving roller and a driven roller) are pressed against the driven rotation shaft 119 so that the driven rotation shaft 119 is rotated by the rotation of the driving rotation shaft 115.

[0039] In this embodiment, the driving rotation shaft 115 and the driven rotation shaft 119 are connected to each other, and are configured so that the axial movement of one of them drives the other. Alternatively, one of the driving roller 111 and the driven roller 112 may be attached to a rotation shaft so as to be able to slide (slide) in the axial direction, and the other roller may be moved in position in the axial direction and linked to that movement.

[0040] <Transport shift operation> Here, the shift operation (jog sorting mode) of the sheet carried into the sheet post-processing device B will be described. The sheet sent from the image forming device A is transported in the order of the straight path entrance 26, entrance rollers 29, first transport rollers 201, second transport rollers 202, and third transport rollers 203. At this time, the entrance sensor S1 simultaneously detects the timing of the sheet delivery. The sheet carried in by the entrance rollers 29 passes through the straight path 28 and the edge position of the sheet is detected by the lateral registration detection sensor S0. The lateral registration detection sensor S0 detects the extent to which the sheet has a lateral registration error X with respect to the center (middle) position.

[0041] When the lateral registration error X is detected by the lateral registration detection sensor S0, the first conveying roller 201, the second conveying roller 202, and the third conveying roller 203 move a predetermined amount in the front and rear directions while conveying the sheet in order, thereby performing a shift operation of the sheet (also called "lateral registration detection process"). After that, the sheet is conveyed by being sorted by the upper conveying path flapper 34 of the branching mechanism to the straight path paper discharge outlet 35 or the upper conveying path 30, and is discharged onto the first tray 49 or the second tray 71.

[0042] <Processing section> The processing section B1 is a post-processing section including a processing tray 37 disposed downstream of the straight path 28 for collating and stacking sheets sent from the straight path paper discharge outlet 35, and a binding processing mechanism for stapling the stacked sheet bundle. As shown in Fig. 3, a step is formed at the straight path paper discharge outlet 35 of the straight path 28, and the processing tray 37 is disposed below the step, and a first paper discharge path (first switchback path) 31 is formed between the straight path paper discharge outlet 35 and the processing tray 37 for reversing the conveying direction from the paper discharge outlet and guiding the sheets onto the tray.

[0043] A sheet carry-in mechanism that carries sheets from the straight path paper discharge outlet 35 onto the tray is disposed between the straight path paper discharge outlet 35 and the processing tray 37, and a positioning mechanism that positions the sheets at a predetermined binding position and a sheet bundle carry-out mechanism that discharges the bound sheet bundle onto the downstream first tray 49 are disposed in the processing tray 37. Each component will be described later.

[0044] 3 bridges the sheet fed from the straight path discharge port 35 between itself and the downstream first tray 49. That is, the sheet fed from the straight path discharge port 35 is supported in a bridge manner with its leading edge on the topmost sheet of the downstream first tray 49 and its trailing edge on the processing tray 37.

[0045] <Saddle section> The saddle section B2 is a post-processing section that collates and stacks the sheets sent from the straight path 28, stitches the center portion, and folds the center portion inward (hereinafter referred to as "magazine finishing"). A second tray 61 is disposed downstream of the saddle section B2 and stores the bound sheet stack. Note that the configuration may be such that one or more sheets are collated and stacked, and only the center portion is folded inward without saddle stitching.

[0046] The saddle portion B2 includes a guide member 66 that accumulates sheets in a bundle, a leading edge regulating stopper 67 that positions the sheets at a predetermined position on the guide member 66, a staple device 63 (saddle stitch stapling unit) that staples the central portion of the sheets positioned by the leading edge regulating stopper 67, and a folding mechanism (a pair of folding rolls 64 and a folding blade 65) that folds the sheet bundle at the central portion after the stapling process.

[0047] The saddle stitch staple unit 63 employs a commonly known mechanism that performs binding processing by moving the sheet stack between a head unit and an anvil unit along the center (line) of the sheets while the sheet stack is sandwiched between them. Also, the folding processing mechanism is configured to insert the fold of the sheet stack into a pair of folding rolls 64 pressed against each other with a folding blade 65, and fold the sheet stack by the rolling of the pair of rolls, as shown in FIG. 2.

[0048] The illustrated processing section B1 and straight path 28 are disposed in a substantially horizontal direction, the saddle path 32 that guides the sheets to the saddle section B2 is disposed in a vertical direction, and the guide member 66 that aligns and stacks the sheets is disposed in a substantially vertical direction. In this way, by disposing the straight path 28 in a direction that crosses the device housing 27, and disposing the saddle path 32 and saddle section B2 in the vertical direction, it is possible to slim down the device.

[0049] A second tray 61 is disposed downstream of the saddle portion B2 and is capable of storing a stack of sheets folded into a magazine shape. The second tray 61 is disposed below the first tray 49. This is because it is assumed that the first tray 49 is used more frequently than the second tray 61, and the position of the first tray 49 is set at a height that makes it easy to remove the sheets on the tray.

[0050] <Punch unit> 5, a punch unit 100 that is disposed on the straight path 28 and punches holes in a sheet fed from the straight path inlet 26 will be described. The punch unit 100 has a plurality of punch members 101a to 101e arranged at predetermined intervals in a direction perpendicular to the sheet conveying direction of the straight path 28, and punches a selected number of holes in the sheet.

[0051] 4 shows the overall configuration of the punch unit 100. The punch unit 100 includes a unit frame 102, a plurality of punch members 101a to 101e arranged on the unit frame 102 so as to be vertically movable, a drive cam for vertically moving each punch member (reciprocating in the punching direction), and a drive motor M7 for driving the drive cam.

[0052] Reference numeral 104 in the figure denotes a waste box, which is disposed below the punch member 101 and stores punched waste paper. The waste box 104 is attached to a guide rail (not shown) so as to be slidable on the device frame 70 (different from the unit frame). Reference numeral 106 in the figure denotes a rotation operation member, which forcibly rotates the drive cam to separate (peel off) the punch member 101 that has bitten into the sheet when a jam occurs in the punch member 101 or when an abnormality occurs in the drive motor M7. For this reason, the rotation operation member 106 is composed of a manual rotation knob connected to a rotation shaft 107 of the drive cam.

[0053] As shown in FIG. 5, the unit frame 102 includes an upper frame 102a having a predetermined length in a direction perpendicular to the sheet conveying direction of the straight path 28, and a lower frame 102b. A plurality of punch members 101a to 101e are arranged on the upper frame 102a at predetermined intervals in a direction perpendicular to the sheet conveying direction (hereinafter referred to as the "conveyance perpendicular direction") so as to be reciprocable (vertically movable) in the punching direction. The lower frame 102b has punch holes (dies) formed at positions facing each punch unit 101. A drive shaft 107 is arranged on the unit frame 102, and a drive cam for moving each punch member 101 up and down is attached to the drive shaft 107. A drive motor M7 is connected to the drive shaft 107 via a transmission mechanism.

[0054] The drive cam is composed of a cylindrical cam member that is axially attached to the drive rotation shaft 107 and corresponds to the multiple punch members 101, and each punch member is connected to this cam member by a connecting pin. Then, the punch members 101 are adapted to move up and down in the punching direction by rotating the drive rotation shaft 107 through a predetermined angle. At this time, a first group 101b, 101d (e.g., punching two holes) of the multiple punch members moves up and down in the punching direction at a first rotation angle of the drive rotation shaft 107, and a second group 101a, 101c, 101e (e.g., punching three holes) moves up and down in the punching direction at a different second rotation angle.

[0055] Therefore, the binding process control unit 95 described later controls the motor M7 to rotate the drive shaft 107 back and forth within a preset angle range, thereby causing the punch members 101b and 101d of the first group to perform a punching motion, and causes the drive shaft 107 to reciprocate within a different angle range, thereby causing the punch members 101a, 101c, and 101e of the second group to perform a punching motion.

[0056] The waste box 104 is disposed below the punch member 101, supported by a guide rail (not shown) provided on the device frame, and is detachable from the front side of the device.

[0057] A drive motor M7 is connected to the drive rotation shaft 107 via a reduction mechanism (gear transmission mechanism), and the rotating member is placed on the front side of the side frame 70f through a hole provided in the side frame 70f so that the operator can rotate it manually. A front cover is placed on the front side of the device so that it can be opened and closed, and the rotation operation member 106 can be operated in the open state. Note that when the cover is in the open state, the drive power is not supplied (cut off) to the drive motor M7.

[0058] [Configuration of processing unit] Next, the configurations of the sheet carry-in mechanism, sheet positioning mechanism, binding mechanism, and sheet bundle carry-out mechanism of processing section B1 will be described.

[0059] <Sheet loading mechanism> As shown in FIG. 3, between the straight path paper discharge outlet 35 and the processing tray 37, there are arranged a reversing conveying mechanism that switches back and conveys the sheet from the straight path paper discharge outlet 35 in the paper discharge direction and the opposite direction to the paper discharge direction, a guide mechanism (sheet guide member) 44 that guides the sheet toward the tray, and a pick-up rotor 46 that guides the sheet to the trailing end regulating section.

[0060] The inversion transport mechanism includes a lift roller 41 that moves up and down between an operating position where it engages with the sheet being brought onto the processing tray 37 and a separated standby position, and a paddle rotor 42 that transports the sheet in the opposite direction to the sheet discharge direction, and the lift roller 41 and the paddle rotor 42 are attached to a swinging bracket 43.

[0061] A swing bracket 43 is disposed on the device frame 27 so as to be swingable about a rotation shaft (e.g., a paper discharge roller shaft), and the rotation shafts of the lift roller 41 and the paddle rotor 42 are bearing-supported on the swing bracket 43. An elevation motor (not shown) is connected to the swing bracket 43, and the swing bracket 43 moves the mounted lift roller 41 and paddle rotor 42 up and down between an operating position where the lift roller 41 and the paddle rotor 42 are engaged with a sheet and a standby position separated from the sheet.

[0062] A drive motor (not shown) is connected to the lift roller 41 and the paddle rotor 42, and a drive is transmitted to rotate the lift roller 41 in a forward and reverse direction and to rotate the paddle rotor 42 in a reverse direction (opposite the direction of paper discharge). The processing tray 37 is also provided with a driven roller 48 that is in pressure contact with the lift roller 41, and nips a single sheet or a stack of sheets and discharges them downstream.

[0063] Between the lift roller 41 and the take-in rotor 46 described later, a guide mechanism is disposed that guides the rear end of a sheet carried onto the processing tray 37 toward the sheet end regulating section 38. The guide mechanism includes a sheet guide member 44 that moves up and down from the dotted line state to the solid line state in Fig. 3, and the sheet guide member 44 retreats to the dotted line position when the sheet is discharged from the straight path paper discharge outlet 35, and guides the sheet rear end onto the processing tray 37 after the sheet rear end has passed the straight path paper discharge outlet 35. For this reason, a drive mechanism (not shown) is connected to the sheet guide member 44, and the sheet guide member 44 moves up and down according to the timing of guiding the sheet rear end from the straight path paper discharge outlet 35 onto the processing tray 37.

[0064] <Seat positioning mechanism> Positioning mechanisms 38, 39 for positioning sheets at a predetermined binding position are arranged on the processing tray 37, and the one shown in the figure includes a sheet end regulating section 38 that abuts and regulates the rear end of the sheet, and a side edge alignment section 39 that positions the side edges of the sheet at reference positions (center reference, one side reference).

[0065] The sheet end regulating section 38 is composed of a stopper member that abuts and regulates the rear end of the sheet as shown in Fig. 3. Also, the side edge alignment member 39 will be described later with reference to Fig. 9, but the sheet is discharged from the straight path 28 with a center reference, and depending on the type of binding mode, the sheet is positioned with the same center reference or with one side reference.

[0066] <Side edge alignment mechanism> 9, the side edge alignment plates 39F, 39R protrude upward from the paper mounting surface 37a of the processing tray 37, have regulating surfaces 39x that engage with the side edges of the sheets, and are arranged in a pair on the left and right to face each other. The pair of side edge alignment parts 39 are arranged on the processing tray 37 so as to be able to reciprocate with a predetermined stroke. This stroke is set according to the size difference between the maximum size sheet and the minimum size sheet and the offset amount by which the sheet stack after alignment is moved to the left or right (offset transport).

[0067] That is, the movement stroke of the left and right side edge alignment plates 39F, 39R is set by the movement amount for aligning sheets of different sizes and the offset amount of the sheet bundle after alignment. When corner binding is performed, the side edge alignment plates 39F, 39R move the sheets discharged based on the center reference by a predetermined amount to the right in the case of right corner binding, and to the left in the case of left corner binding (offset movement). This offset movement may be performed one by one each time a sheet is brought into the processing tray 37 (for each brought-in sheet), or may be performed for each bundle to perform binding processing after aligning the sheets into a bundle.

[0068] 9, the side edge alignment section 39 includes a right edge alignment member 39F (apparatus front side) and a left edge alignment member 39R (apparatus rear side), and both side edge alignment members are supported on the processing tray 37 so that regulating surfaces 39x that engage with the side edges of sheets move toward or away from each other. The processing tray 37 is provided with a slit groove (not shown) that penetrates from the front to the back, and the side edge alignment section 39 having the regulating surfaces 39x that engage with the side edges of sheets is slidably fitted into the slit groove.

[0069] Each side edge alignment plate 39F, 39R is slidably supported by a plurality of guide rollers 80 (which may be rail members) on the rear side of the tray, and a rack 81 is integrally formed. The left and right racks 81 are connected to alignment motors M1, M2 via pinions 82. The left and right alignment motors M1, M2 are composed of stepping motors, and are configured to detect the positions of the left and right side edge alignment plates 39F, 39R using a position sensor (not shown), and to move each alignment member to the left or right by a specified amount based on the detected value. Note that the mechanism is not limited to the rack-pinion mechanism shown in the figure, and each side edge alignment plate 39F, 39R may be fixed to a timing belt and connected to a motor that reciprocates the timing belt left and right by a pulley.

[0070] In the above configuration, the binding process control unit 95, which will be described later, makes the left and right side edge alignment members 39F and 39R wait at a predetermined waiting position (a position of the sheet width size + α) based on the sheet size information provided by the image forming apparatus A. In the case of "multi-binding", the sheet is carried onto the processing tray 37, and the alignment operation is started when the sheet end hits the sheet end regulating unit 38. This alignment operation is performed by rotating the left and right alignment motors M1 and M2 by the same amount in opposite directions (approaching directions). Then, the sheets carried onto the processing tray 37 are positioned based on the sheet center and stacked into a bundle. By repeating the sheet carrying-in operation and the alignment operation, the sheets are collated and accumulated into a bundle on the processing tray 37. At this time, sheets of different sizes are positioned based on the center. In the case of "corner binding", the sheet is carried onto the processing tray 37, and the alignment operation is started when the sheet end hits the sheet end regulating unit 38. This aligning operation is performed by making the movement amount of the aligning plate on the side of the binding position different from that on the side opposite to the binding position, and the movement amount is set so that the sheet corner is positioned at a preset binding position.

[0071] <Binding processing mechanism> A binding mechanism 47 that binds the sheet stack accumulated on the paper mounting surface 37a is disposed on the processing tray 37. The paper mounting surface 37a on the processing tray 37 is positioned at a predetermined binding position by a positioning mechanism (a sheet end regulating portion 38 and a side edge aligning portion 39). The binding mechanism 47 is configured as a binding unit 47 (hereinafter the same as "staple unit") that staples the sheet stack.

[0072] A binding processing mechanism 47 is arranged in the processing tray 37 to bind the rear end of the sheet conveyed from the straight path paper discharge port 35. The binding processing mechanism 47 is composed of a staple unit 47 that can be moved along the rear end of the paper support surface 37a of the processing tray 37 as shown in FIG. 8.

[0073] 8 and 9 show the staple unit 47 disposed on the processing tray 37. In Fig. 9, the staple position Cp1 is set at the sheet corner located on the left side of the drawing. The staple unit 47 moves at a predetermined stroke SL1 along a first traveling rail 53 and a second traveling rail 54 formed on the device frame 27b.

[0074] 9 shows the sheets carried into the processing tray 37 and the movement stroke SL1 of the binding unit 47. Different sizes of sheets are carried into the processing tray 37, from the maximum size sheet to the minimum size sheet, with the center as a reference. A pair of left and right side edge alignment plates 39F, 39R align the sheets so that the different sizes of sheets match with each other, with the binding side edge of the sheet (the left edge in the figure) as a reference. For this reason, the left and right side edge alignment plates 39F, 39R are connected to different drive motors M1, M2, respectively, and a binding process control unit 95, which will be described later, sets the movement amount of the left and right side edge alignment plates 39F, 39R according to the sheet size.

[0075] In addition, the binding process control unit 95 described later aligns the sheets based on the center reference in the binding process other than the binding process of the sheet corners, for example, in the multi-binding mode described later. In this case, the left and right side edge alignment plates 39F, 39R position the sheets at the binding position by moving toward the sheet center by the same amount from the standby position.

[0076] 9, the binding unit 47 moves a stroke SL1 between a standby position Wp1 (first standby position) and the binding position Cp1. That is, the binding unit 47 moves back and forth between the standby position Wp1 and the binding position Cp1 along traveling rails 53, 54 (guide grooves, guide rods, etc.). The first standby position Wp1 is set outside the maximum size sheet to be bound on the processing tray 37.

[0077] Fig. 10 shows the configuration of the binding unit 47. A pair of left and right pulleys 58a, 58b are arranged on the device frame 27b along the movement area (left and right direction in Fig. 9) of the staple unit 47, a timing belt 59 (toothed belt) is stretched between the two pulleys, and a drive motor M3 (stepping motor) is connected to one of the pulleys, the pulley 58a.

[0078] <Staple moving mechanism> As shown in Fig. 8, the staple unit 47 is mounted to the device frame (chassis frame) 27b, which is fixed to the side frames 70f, 70r by penetrating an opening provided in the side frame 70f of the device frame 70, so as to be movable at a predetermined stroke. A first traveling rail 53 and a second traveling rail 54 are arranged on the device frame 27b. A traveling rail surface 53x is formed on the first traveling rail 53, and a traveling cam surface 54x is formed on the second traveling rail 54. The traveling rail surface 53x and the traveling cam surface 54x cooperate with each other to support the staple unit 47 (hereinafter referred to as "moving unit" in this section) so as to be reciprocatable at a predetermined stroke, and at the same time control its angular posture.

[0079] The first traveling rail 53 and the second traveling rail 54 are formed with a rail surface 53x and a traveling cam surface 54x so as to reciprocate within the movement range of the moving unit. As shown in Fig. 10, a timing belt 59 connected to a drive motor (travel motor) M3 is fixed to the staple unit 47. The timing belt 59 is wound around a pair of pulleys 58a, 58b journaled on the device frame 27b, and the drive motor M3 is connected to one of the pulleys. Therefore, the forward and reverse rotation of the drive motor M3 causes the staple unit 47 to reciprocate with a stroke SL1.

[0080] The staple unit 47 engages with the first and second traveling rails 53, 54 as follows. As shown in Fig. 8, the staple unit 47 is provided with a first rolling roller 83 (rail fitting member) that engages with the traveling rail surface 53x, and a second rolling roller 84 (cam follower member) that engages with the traveling cam surface 54x. The staple unit 47 is also formed with ball-shaped sliding rollers 47x (two in the figure) that engage with the support surface of the frame 27b. The staple unit 47 is also formed with guide rollers 47y that engage with the bottom surface of the bottom frame, preventing the staple unit 47 from floating up from the device frame 27b.

[0081] With the above-mentioned configuration, the staple unit 47 is supported movably by the device frame 27b with the sliding rollers 47x and the guide rollers 47y. The first rolling rollers 83 and the second rolling rollers 84 rotate along the traveling rail surface 53x and the traveling cam surface 54x, respectively, while following the rail surface 53x and the cam surface 54x.

[0082] <Stack tray lifting mechanism> As shown in Fig. 11, the sheet post-processing device B is provided with a first tray 49. The first tray 49 is configured to be raised and lowered according to the amount of sheets loaded. For this purpose, guide rollers 85 are provided at two positions, one above the other, at the base end of the first tray 49, and the guide rollers 85 are fitted and supported by lifting guides 86 provided on the device frame 27. A lifting gear 88 is provided at the base end of the first tray 49 and is connected to a lifting rack gear 87. A lifting motor M4 is connected to the lifting gear 88. Therefore, by controlling the rotation of the lifting motor M4, the first tray 49 is raised and lowered according to the amount of sheets loaded.

[0083] <Sheet bundle discharge mechanism> A sheet bundle discharge mechanism that discharges the stapled sheet bundle toward the downstream first tray 49 is disposed on the processing tray 37. Known configurations for transporting the sheet bundle downstream include a method of transporting the sheet bundle by a pair of rollers that are in pressure contact with each other (discharge roller mechanism) and a conveyor mechanism that pushes out the rear ends of the sheets with a push-out member that moves from the upstream side to the downstream side along the tray surface. The illustrated device employs both of these mechanisms.

[0084] The sheet bundle discharge mechanism is shown in Fig. 12. The conveyor mechanism includes a push-out protrusion 45 that transfers the sheets from a binding position (processing position) located upstream along the processing tray 37 to a stack tray (first tray) 49 downstream, a conveyor belt 45v that moves the push-out protrusion, and a drive motor M6. A driven roller 48 is disposed at the discharge outlet (the boundary between the paper mounting surface 37a and the first tray 49) of the processing tray 37, and a lift roller 41 that is in pressure contact with the driven roller 48 is disposed opposite the driven roller 48, and the driven roller 48 and the lift roller 41 form a discharge roller mechanism.

[0085] Therefore, the processing tray 37 is provided with conveyor mechanisms 45, 45v for pushing the sheet bundle from the upstream side to the downstream side, and discharge roller mechanisms 48, 41 for nipping and discharging the sheet bundle. FIG. 12(a) shows a state in which the sheet bundle is located at the binding position on the processing tray 37. At this time, the conveyor mechanisms 45, 45v and the discharge roller mechanisms 48, 41 are in operation. FIG. 12(b) shows a state in which the sheet bundle is being transferred from the processing position to the downstream side, and the sheet bundle is sent downstream by the positional movement of the push-out protrusion 45 and the rotation of the discharge roller mechanisms 48, 41. FIG. 12(c) shows a state immediately before the sheet bundle is discharged to the first tray 49 on the downstream side, and the sheet bundle on the processing tray is gradually (at a low speed) sent downstream by the rotation of the discharge roller mechanisms 48, 41. At this time, the push-out protrusion 45 waits at the illustrated position and returns (moves backward) to the initial position.

[0086] <Configuration of the staple unit> The configuration of the above-mentioned staple unit will be described with reference to Fig. 13. The staple unit 47 is configured as a unit separate from the sheet post-processing device B. A box-shaped unit frame 47a, a drive cam 47d axially supported by the unit frame 47a so as to be swingable, and a drive motor M4 for rotating the drive cam 47d are mounted on the unit frame 47a.

[0087] The staple head 47b and the anvil member 47c are disposed on the drive cam 47d at the stapling position, and the staple head 47b is biased by a biasing spring (not shown) on the drive cam 47d from an upper standby position to a lower staple position (anvil member) to move up and down. A staple cartridge 52 is detachably mounted on the unit frame 47a.

[0088] The staple cartridge 52 stores straight blank staples, and a staple feed mechanism supplies the staples to the staple head 47b. The staple head 47b has a former member that bends the straight staples into a U-shape and a driver that presses the bent staples into a sheet stack. With this configuration, the drive motor M4 rotates the drive cam 47d, storing energy in the spring. When the rotation angle reaches a predetermined angle, the staple head 47b vigorously descends toward the anvil member 47c. With this operation, the staple is bent into a U-shape and then inserted into the sheet stack by the driver. The tip of the staple is then bent by the anvil member 47c and stapled.

[0089] A staple feed mechanism is provided between the staple cartridge 52 and the staple head 47b, and a sensor (empty sensor) is provided in the staple feed mechanism to detect the absence of staples. A cartridge sensor (not shown) is provided in the unit frame 47a to detect whether the staple cartridge 52 is inserted.

[0090] The staple cartridge 52 employs a structure in which staples connected in a strip shape are stored in a box-shaped cartridge in a stacked manner, or in a roll-like manner. The unit frame 47a is provided with circuits for controlling the above-mentioned sensors and a circuit board for controlling the drive motor M4, and is configured to issue a warning signal when the staple cartridge 52 is not stored or when the staples are empty. The staple control circuit is configured to control the drive motor M4 to execute a stapling operation in response to a staple signal, and to issue an "operation end signal" when the staple head portion 47b moves from the standby position to the stapling position and then returns to the standby position.

[0091] <Control configuration explanation> The control configuration of the image forming system in Fig. 1 will be described with reference to Fig. 14. The image forming system shown in Fig. 14 includes a control unit 90 (hereinafter referred to as the "main body control unit") of the image forming apparatus A and a control unit 95 (hereinafter referred to as the "binding process control unit") of the sheet post-processing apparatus B. The main body control unit 90 controls a print control unit 91, a paper feed control unit 92, and an input unit 93 (control panel).

[0092] Then, the "image formation mode" and "post-processing mode" are set based on user operations received via the input unit 93 (control panel). In the image formation mode, for example, mode settings such as color / monochrome printing, double-sided / single-sided printing, and image formation conditions such as sheet size, sheet paper quality, number of printout copies, enlarged / reduced printing, are set. In the "post-processing mode", for example, "printout mode", "bookbinding processing paper discharge mode", "staple binding processing mode", and "jog sorting mode" are set.

[0093] The main body control unit 90 also transfers data indicating that the mode is the post-processing mode, the number of sheets, the number of copies, and the thickness of the sheets on which images are formed, to the binding process control unit 95. At the same time, the main body control unit 90 transfers a job end signal to the binding process control unit 95 each time image formation is completed.

[0094] Regarding the post-processing modes, the "printout mode" is a mode in which sheets from the straight path paper discharge port 35 are stored in the stack tray 49 via the processing tray 37 without being bound. In this case, the sheets are stacked on top of each other on the processing tray 37, and the stacked sheet bundle is conveyed to the stack tray 49 in response to a job end signal from the main body control unit 90.

[0095] The "product processing and ejection mode" is a mode in which the sheets on which images are formed are collated, bound, and then folded to complete the bookbinding process. Details will be described later with reference to FIG.

[0096] The "staple binding processing mode" is a mode in which sheets from the straight path paper discharge outlet 35 are accumulated and collated on the processing tray 37, and this sheet bundle is bound and then stored in the stack tray 49. In this case, the operator specifies that the sheets on which images are formed are, in principle, of the same paper thickness and size. In this staple binding processing mode, one of "multi-binding," "right corner binding," and "left corner binding" is selected and specified.

[0097] In the "jog sorting mode," sheets on which images are formed by the image forming apparatus A are separated into a group in which the sheets are offset and accumulated, and a group in which the sheets are not offset. The stack tray alternately stacks the sheet bundles that have been offset and the sheet bundles that have not been offset.

[0098] <Binding process control section> The binding process control unit 95 operates the sheet post-processing device B in accordance with the post-processing mode set by the image formation control unit 90. The binding process control unit 95 includes a control CPU. A ROM 96 and a RAM 97 are connected to the binding process control unit 95, and the operation of the sheet post-processing device B in this embodiment is executed by the control program stored in the ROM 96 and the control data stored in the RAM 97. For this reason, the binding process control unit 95 controls the drive circuits of all the drive motors described above, and starts, stops, and controls the forward and reverse rotation of each motor.

[0099] The bookbinding process discharge mode, which is one of the post-processing modes, will be described with reference to Fig. 15. S101 to S102 indicate the process in the image forming apparatus A, and S103 to S113 indicate the process in the sheet post-processing apparatus B. That is, the process in S101 to S102 is realized, for example, by the main body control unit 90 reading a program stored in ROM into RAM and executing it. The process in S103 to S115 is realized, for example, by the binding process control unit 95 reading a program stored in ROM 96 into RAM 97 and executing it.

[0100] In S101, the main body control unit 90 forms an image on a sheet, and in S102, the main body control unit 90 ejects the sheet on which the image has been formed. The sheet on which the image has been formed by the image forming apparatus A is guided to the straight path .

[0101] In S103, the binding process control unit 95 controls each motor to transport the sheet discharged from the image forming apparatus A along a path to the leading end regulating stopper 67. The sheet transport control in S103 will be described later.

[0102] In S104, the binding process control unit 95 moves the position of the leading edge regulating stopper 67 to a position where the sheet can be introduced. At that time, the binding process control unit 95 sets the position of the leading edge regulating stopper 67 based on the size of the sheet in the conveying direction received from the image forming apparatus A. In S105, the binding process control unit 95 causes the leading edge regulating stopper 67 after the movement to introduce the sheet. The introduced sheet is brought into a state where it is abutted against the receiving portion of the leading edge regulating stopper 67, so that the leading edges of the sheets are aligned.

[0103] In S106, the binding process control unit 95 determines whether the final sheet has been conveyed to the leading edge regulating stopper 67 based on the specified number of sheets for post-processing. The process from S105 is repeated until it is determined that the final sheet has been conveyed to the leading edge regulating stopper 67. If it is determined that the final sheet has been conveyed to the leading edge regulating stopper 67, the process proceeds to S107.

[0104] In S107, the binding process control unit 95 moves the position of the leading end regulating stopper 67 where the specified number of sheets have been conveyed to the bottom. In S108, the binding process control unit 95 aligns the sheets in the width direction. The alignment of the sheets here is performed by a side end regulating member (not shown).

[0105] In S109, the binding process control unit 95 rotates the folding roll 64. In S110, the binding process control unit 95 advances the folding blade 65 in the folding direction. In S111, the binding process control unit 95 determines whether the rotation amount of the folding roller 64 reaches a predetermined amount. If it is determined that the rotation amount of the folding roller 64 has not reached the predetermined amount, the process of S111 is repeated. If it is determined that the rotation amount of the folding roller 64 has reached the predetermined amount, the process proceeds to S112. In S112, the binding process control unit 95 retreats the folding blade 65. In S113, the binding process control unit 95 conveys the folded sheet, which has been subjected to the above folding process, in the paper discharge direction by the downstream saddle portion paper discharge roller. As a result, the folded sheet is stored in the second tray 61 via the saddle discharge path 68.

[0106] In the above, an example in which the folding process is performed after the position of the leading edge regulating stopper 67 is moved in S107 has been described, but the present invention is not limited to this configuration. After the position of the leading edge regulating stopper 67 is moved and before the folding process is performed, other post-processing may be performed. For example, binding may be performed. For example, based on receiving a job end signal from the image forming apparatus A, a binding unit (saddle stitching unit) (not shown) provided in the saddle section B2 may be moved to the center of the sheets to perform the binding process. In this case, the binding process is performed at one or two specified positions.

[0107] Image formation continues in the image forming apparatus A even while post-processing is being performed in the saddle portion B2. Therefore, in this embodiment, a buffer operation is performed to accumulate sheets conveyed from the image forming apparatus A in the sheet processing apparatus B. This allows post-processing to be continued without decreasing the frequency at which sheets are discharged from the image forming apparatus A, i.e., without decreasing the productivity of the image forming apparatus A.

[0108] An overview of the sheet buffer operation in the sheet processing apparatus B executed in S103 will be described with reference to Fig. 16 to Fig. 23. Fig. 16 to Fig. 23 show cross-sectional views seen from the side of the sheet processing apparatus B. Hereinafter, the first conveying roller 201, the second conveying roller 202, and the third conveying roller 203 will be referred to as the shift roller 201, the shift roller 202, and the intermediate conveying roller 203.

[0109] First, a buffer operation for a sheet having a small size in the sheet conveying direction will be described. In this embodiment, as an example of the definition of a small size, a size that fits within the path length of the straight path 28 (e.g., A4 portrait) is defined as a small size.

[0110] Fig. 16(a) shows how the processes of S109 to S112 in Fig. 15 are performed in the saddle section B2 on the sheet S0 that is previously present in the sheet processing device B. Fig. 16(a) also shows a state in which the sheet S1 discharged from the image forming device A has been transported to the entrance roller 29 and the shift roller 201 via the straight path entrance 26. In the state shown in Fig. 16(a), a lateral registration error is detected for the sheet S1, which will be described later. Fig. 16(b) shows a state in which the leading edge of the sheet S1 has been transported further to a position beyond the shift roller 202. At this time, a lateral registration adjustment is performed on the sheet S1, which will be described later.

[0111] Fig. 17(a) shows a state where the leading edge of the sheet S1 has been transported to a position beyond the discharge roller 36. Fig. 17(b) shows a state where the position of the upper flapper 33a has been moved to the buffer path guiding position.

[0112] FIG. 18(a) shows a state where the position of the lower flapper 33b is moved to the buffer path guide position. The movement of the upper flapper 33a and the lower flapper 33b forms a path for conveying the sheet S1 to the saddle buffer path P2. FIG. 18(b) shows a state where the sheet S1 is retreated to the saddle buffer path P2. In this manner, in this embodiment, by retreating the sheet S1 to the saddle buffer path P2, the sheet discharged subsequently from the image forming apparatus A can be continuously received by the straight path 28. Also, FIG. 18(b) shows that the post-processing (folding process) for the sheet S0 is being performed. Here, being performed refers not only to the folding process, but also to a state where the sheet S0 has not yet been discharged to the second tray 61 even after the folding process itself has been completed.

[0113] Fig. 19(a) shows a state in which the sheet S1 is further conveyed toward the fourth tray discharge port 305 of the saddle buffer path P2. At this time, post-processing of the sheet S0 is being performed. Fig. 19(b) shows a state in which the position of the lower flapper 33b has been moved. By moving the lower flapper 33b, the following sheet S2 can be received in the straight path 28.

[0114] FIG. 20(a) shows a state where sheet S1 is located at a predetermined position in saddle buffer path P2. As shown in FIG. 20(a), the entire length of the sheet in the conveying direction is retreated to saddle buffer path P2. At this time, post-processing for sheet S0 is being performed. FIG. 20(b) shows a state where sheet S2, which is subsequently discharged from image forming apparatus A, is conveyed to inlet roller 29 and shift roller 201 via straight path inlet 26. In the state of FIG. 20(b), detection of lateral registration error for sheet S2, which will be described later, is performed. At this time, sheet S1, which is located in saddle buffer path P2, is subjected to lateral registration adjustment so as to match the lateral registration error of sheet S2. The operation will be described later. At this time, post-processing for sheet S0 is being performed.

[0115] FIG. 21(a) shows a state in which sheets S1 and S2 are transported synchronously to the shift rollers 202. The transport synchronization between the sheets is performed, for example, based on the drive pulses of a stepping motor. At this time, post-processing for sheet S0 is being performed. FIG. 21(b) shows a state in which sheets S1 and S2 are transported synchronously to just before the intermediate transport rollers 203. At this time, lateral registration adjustment is performed to align sheets S1 and S2 with the center. This operation will be described later. At this time, post-processing for sheet S0 is being performed.

[0116] FIG. 22(a) shows a state where sheets S1 and S2 are transported to the discharge roller 36 while overlapping each other. At this time, the rear ends of sheets S1 and S2 have passed through the shift roller 201. At this time, post-processing for sheet S0 is being performed. FIG. 22(b) shows a state where the positions of the upper flapper 33a and the lower flapper 33b have been moved. By the movement of the upper flapper 33a and the lower flapper 33b, a path for transporting sheets S1 and S2 to the saddle portion B2 is formed. At this time, sheet S0 is discharged to the second tray 61. FIG. 23 shows a state where sheets S1 and S2 are transported to the leading edge regulating stopper 67.

[0117] Thus, according to this embodiment, even if post-processing of a sheet is being performed in the saddle section B2, the sheet S1 can be evacuated to the saddle buffer path P2 and the succeeding sheet S2 can be received from the image forming apparatus A. This makes it possible to perform post-processing of the sheet without impairing the productivity of the image forming apparatus A. Furthermore, as a result of the leading edge of the sheet hitting the leading edge regulation stopper 67, the sheets S1, S2 are accumulated in order from the bottom in the stacked state, so that the order among the multiple sheets is maintained.

[0118] In some of Figs. 16 to 23, it has been described that the lateral registration error is detected and the lateral registration is adjusted. Hereinafter, the detection of the lateral registration error and the lateral registration adjustment will be described with reference to Figs. 24 to 33. The upper parts of Figs. 24 to 33 are simplified diagrams showing the configuration in the vicinity of the straight path 28 in Figs. 16 to 23. The lower parts of Figs. 24 to 33 are diagrams showing the upper straight path 28 as viewed from the top of the device. Also, the inlet roller 29, the shift roller 201, the shift roller 202, the intermediate conveyor roller 203, and the buffer rollers 302a and 302b in the lower parts of Figs. 24 to 33 correspond to the inlet roller 29, the shift roller 201, the shift roller 202, the intermediate conveyor roller 203, and the buffer rollers 302a and 302b in the upper parts of Figs. 24 to 33. Also, as shown in the upper part, the roller pairs arranged on the straight path 28 appear to overlap each other when viewed from above. On the other hand, the rollers arranged in the saddle buffer path P2 appear misaligned when viewed from above due to the curved conveying path, and this is shown.

[0119] Fig. 24(a) shows a state in which sheet S1 is discharged from image forming apparatus A. At this time, the central axis of sheet S1 is usually not positioned at the center in the width direction, and a lateral registration error occurs. Fig. 24(b) shows a state in which sheet S1 is conveyed to just before shift roller 201. At this time, registration detection sensor 100 detects the lateral registration error of sheet S1.

[0120] Fig. 25(a) shows a state where detection of the lateral registration error of the sheet S1 by the registration detection sensor 100 has been completed. Fig. 25(b) shows a state where the sheet S1 has been transported to a position beyond the shift roller 202. At this time, the nip of the inlet roller 29 is released. In other words, the sheet S1 is in a state where it is nipped by the shift roller 201 and the shift roller 202. The shift roller 201 and the shift roller 202 can be shifted by the transport roller shift mechanism described above.

[0121] In Fig. 26(a), the shift roller 201 and the shift roller 202 perform lateral registration adjustment so as to align the central axis of the sheet S1 in the conveying direction with the center. This corresponds to the state in Fig. 16(b). Fig. 26(b) shows a state in which the sheet S1 has been conveyed to a position beyond the intermediate conveying roller 203. At this time, the inlet roller 29 is in a nip state, and is in a state in which the sheet S1 can receive the succeeding sheet.

[0122] Fig. 27(a) is a diagram showing a state where the position of the shift roller 201 is returned to the original position (receiving position). Fig. 27(b) is a diagram showing a state where the sheet S1 is reversely conveyed to the saddle buffer path P2 by the intermediate conveying rollers 203, the shift rollers 202, the buffer rollers 302a, and the buffer rollers 302b. That is, in the state of Fig. 27(b), the intermediate conveying rollers 203 and the shift rollers 202 are controlled to perform a reverse operation. At this time, the upper flapper 33a and the lower flapper 33b are in a state where they have moved as shown in Fig. 18(a).

[0123] Fig. 28(a) is a diagram showing a state where the shift roller 202 has been returned to its original position (receiving position). Fig. 28(b) shows a state where the sheet S2 is subsequently discharged from the image forming apparatus A and conveyed to a position beyond the shift roller 201. At this time, the central axis of the sheet S2 is not positioned at the center in the width direction, and a lateral registration error has occurred.

[0124] Fig. 29(a) shows a state in which the registration detection sensor 100 detects the lateral registration error of the sheet S2. Fig. 29(b) shows a state in which the registration detection sensor 100 has finished detecting the lateral registration error of the sheet S2 and the sheet S2 has been further conveyed to just before the shift roller 202.

[0125] Fig. 30(a) is a diagram showing a state where the sheet S1 located in the saddle buffer path P2 is adjusted to match the lateral registration error of the sheet S2 by the shift operation of the buffer rollers 302a and 302b. That is, the first shift operation is performed on the sheet S1. This corresponds to the state of Fig. 21(a). The buffer rollers 302a and 302b can be shifted by the above-mentioned conveying roller shift mechanism. Fig. 30(b) shows a state where the sheets S1 and S2 are conveyed synchronously to the downstream side of the straight path 28.

[0126] FIG. 31(a) shows a state in which the sheets S1 and S2 are conveyed synchronously to a position beyond the shift roller 202. At this time, the nip of the inlet roller 29 is released. In other words, the sheet S2 overlaps the sheet S1 and is nipped by the shift roller 201 and the shift roller 2022. FIG. 31(b) shows a state in which the shift rollers 201, 202 and the buffer rollers 302a, 302b perform a shift operation to adjust the lateral registration of the sheets S1 and S2 to the center. This corresponds to the state in FIG. 21(b). In other words, the second shift operation is performed on the sheet S1.

[0127] Fig. 32(a) is a diagram showing a state where the sheets S1 and S2 are overlapped and transported to a position beyond the intermediate transport roller 203. Fig. 32(b) is a diagram showing a state where the shift roller 201 has been moved to its original position (receiving position). At this time, the upper flapper 33a and the lower flapper 33b are in a state where they have been moved to positions where the sheets can be guided to the saddle path 32, as shown in Fig. 22(b).

[0128] Fig. 33(a) is a diagram showing a state in which the sheet S1 and the sheet S2 are overlapped and conveyed to the saddle path 32. Fig. 33(b) is a diagram showing a state in which the shift roller 202 has been moved to the original position (receiving position).

[0129] In this manner, according to this embodiment, it is possible to adjust the registration error of each sheet discharged from the image forming apparatus A and continuously received on the straight path 28, and the sheet S1 and the sheet S2 do not rub against each other.

[0130] Fig. 34 is a flowchart showing a process of a sheet buffer operation executed in the sheet processing apparatus B. The process of Fig. 34 is realized, for example, by the binding process control unit 95 reading a program stored in the ROM 96 into the RAM 97 and executing the program.

[0131] In S201, sheet S1 is discharged from image forming apparatus A. The process of S201 is executed in image forming apparatus A. In S202, binding process control unit 95 moves the sheet support to an operating position. The sheet support is a member for preventing the sheet transported on straight path 28 from falling. In S203, binding process control unit 95 detects that sheet S1 has reached inlet rollers 29. In S204, binding process control unit 95 detects a lateral registration error of sheet S1 by registration detection sensor 100.

[0132] In S205, the binding process control unit 95 separates the inlet roller 29 (releases the nip). This is to adjust the lateral registration of the sheet S1 by the shift operation of the shift roller 201 and the shift roller 202 in a later stage. In S206, the binding process control unit 95 starts the shift operation of the shift roller 201 and the shift roller 202. Here, the shift direction is a direction to eliminate the lateral registration error of the sheet S1. In S207, the binding process control unit 95 accelerates the sheet S1 and conveys it to the downstream side of the straight path 28. In S208, the binding process control unit 95 completes the shift operation of the shift roller 201 and the shift roller 202.

[0133] In S209, the binding process control unit 95 again brings the inlet rollers 29 into a nipped state. In S210, the binding process control unit 95 returns the shift rollers 201 to their original positions (receiving positions). This corresponds to the state in FIG. 27(a).

[0134] In S211, the binding process control unit 95 starts moving the upper flapper 33a to the buffer path guide position, and in S212, starts moving the lower flapper 33b to the buffer path guide position. In S213, the binding process control unit 95 completes moving the upper flapper 33a to the buffer path guide position, and in S214, the binding process control unit 95 completes moving the lower flapper 33b to the buffer path guide position. This corresponds to the state of FIG. 18(a).

[0135] In S215, the binding process control unit 95 stops the shift roller 202 and the intermediate conveying roller 203. In S216, the binding process control unit 95 reverses the shift roller 202 and the intermediate conveying roller 203 to convey the sheet S1 in the reverse direction. In S217, the binding process control unit 95 starts moving the lower flapper 33b to its original position (receiving position). In S218, the binding process control unit 95 retreats the sheet S1 to the buffer path P2. In S219, the binding process control unit 95 completes moving the lower flapper 33b to its original position. This corresponds to the state of FIG. 19(b). In S220, the binding process control unit 95 moves the shift roller 202 to its original position (receiving position). This corresponds to the state of FIG. 28(a).

[0136] In S221, the sheet S2 is discharged from the image forming apparatus A. The process of S221 is executed in the image forming apparatus A.

[0137] In S222, the binding process control unit 95 detects a lateral registration error of the sheet S2 by the registration detection sensor 100. In S223, the binding process control unit 95 performs a lateral registration adjustment so that the sheet S1 located in the saddle buffer path P2 is adjusted to match the lateral registration error of the sheet S2 by a shift operation of the buffer rollers 302a and 302b.

[0138] In S224, the binding process control unit 95 separates the inlet rollers 29 (releases the nip). This is to perform lateral registration adjustment of the sheets S1 and S2 by the shifting operations of the shift rollers 201 and 202 and the buffer rollers 302a and 302b in the subsequent stage.

[0139] In S225, the binding process control unit 95 conveys the sheets S1 and S2 to the shift rollers 202 in an overlapping state.

[0140] In S226, the binding process control unit 95 performs registration adjustment to align the central axis of the sheet S1 with the center by the shift operation of the buffer rollers 302a and 302b and the shift roller 202. On the other hand, in S227, the binding process control unit 95 performs registration adjustment to align the central axis of the sheet S2 with the center by the shift operation of the shift rollers 201 and 202. The process of S226 and the process of S227 are performed simultaneously in parallel.

[0141] In S228, the binding process control unit 95 again brings the inlet rollers 29 into a nipped state. In S229, the binding process control unit 95 returns the shift rollers 201 to their original positions (receiving positions). This corresponds to the state in FIG. 32(b).

[0142] In S230, the binding process control unit 95 starts moving the lower flapper 33b to the saddle path guide position, and in S231, starts moving the upper flapper 33a to the saddle path guide position. In S232, the binding process control unit 95 completes moving the lower flapper 33b to the saddle path guide position, and in S233, completes moving the upper flapper 33a to the saddle path guide position. This corresponds to the state of FIG. 22(b).

[0143] In S234, the binding process control unit 95 reversely operates the intermediate conveying roller 203 and the shift roller 202 to convey the sheets S1 and S2 in a stacked manner to the saddle path 32 in the reverse direction.

[0144] In S235, the binding process control unit 95 moves the upper flapper 33a to the original position (receiving position), and in S236, the binding process control unit 95 moves the lower flapper 33b to the original position (receiving position).

[0145] In S237, the binding process control unit 95 performs saddle processing on the sheets S1 and S2 carried into the leading edge regulating stopper 67. This corresponds to the processes of S109 to S111 in Fig. 15. In S238, the binding process control unit 95 stores the sheets S1 and S2 that have been subjected to the saddle processing in the second tray 61 via the saddle discharge path 68 (discharge unit). Thereafter, the process in Fig. 34 ends.

[0146] The following describes the buffer operation of a large-size sheet, which is longer in the sheet transport direction than a small-size sheet, in terms of the differences from the small-size sheet.

[0147] Fig. 35 is a flow chart showing a process of a buffer operation for a large size sheet executed in the sheet processing apparatus B. The process of Fig. 35 is realized, for example, by the binding process control unit 95 reading out a program stored in the ROM 96 into the RAM 97 and executing it. The process of Fig. 35 differs from Fig. 34 in that the processes of S303, S307, S311, S324, and S331 are executed. The processes of S301, S302, S304 to S306, S308 to S310, S312 to S323, S325 to S330, and S332 to S341 are the same as those explained in S201, S202, S203 to S205, S206 to S208, S210 to S221, S222 to S227, and S229 to S238, and therefore the explanation thereof will be omitted.

[0148] In S303, the binding process control unit 95 moves the upper conveying path flapper 34 to the upper conveying path guide position. This forms a path along which the sheet conveyed on the straight path 28 is guided to the upper conveying path 30. When the rear end of the small-sized sheet passes through the shift roller 202, the leading edge is located near the discharge roller 36. However, when the rear end of the large-sized sheet passes through the shift roller 202, the leading edge passes through the nip point of the discharge roller 36. In this case, the leading edge of the large-sized sheet comes out to the processing tray 37, and there is a risk that the sheet may come into contact with a sheet or a component on the processing tray 37 and be damaged. Therefore, in this embodiment, in the case of a large-sized sheet, the sheet is conveyed on the upper conveying path 30 as shown in Figures 36 to 39, so that the above-mentioned damage to the sheet can be prevented. The state in Figure 36 corresponds to the state in Figure 17 in the case of a small-sized sheet. The state in Figure 37 corresponds to the state in Figure 18(a) in the case of a small-sized sheet. The state in Figure 38 corresponds to the state in Figure 22 in the case of a small-sized sheet. The state of FIG. 39 corresponds to the state of FIG. 32 in the case of a small size sheet.

[0149] In S307 and S324, the binding process control unit 95 separates the intermediate conveying rollers 203 and the upper conveying rollers 303. This enables the shift rollers 201 and 202 to perform registration adjustment for large-sized sheets.

[0150] In S311 and S331, the binding process control unit 95 again brings the intermediate conveying rollers 203 and the upper conveying rollers 303 into a nip state, thereby enabling conveyance of a large size sheet.

[0151] As described above, according to this embodiment, in a configuration in which post-processing is performed on sheets continuously supplied from the image forming apparatus A, it is possible to further improve productivity.

[0152] Furthermore, by providing a path configuration such as the saddle buffer path P2, buffer operation is possible even if the straight path is short in length, making it possible to reduce product size while maintaining the advantages of transporting thick paper using an approximately straight path, and preventing a decrease in productivity.

[0153] The disclosure of this embodiment includes the following post-processing device. (Item 1) A receiving section for receiving the sheet; a detection unit that detects a deviation of the sheet received by the receiving unit in a direction perpendicular to a conveying direction; a first conveying roller for conveying the sheet received by the receiving section; a guide portion that forms a conveying path together with the first conveying roller and is configured to be able to switch the conveying path of the sheet; a stacking unit that is provided on one side of the conveying path and receives the sheet conveyed in a reverse direction by the reverse operation of the first conveying roller via the guide unit, from the rear end of the sheet, and stacks the sheet; a post-processing unit that performs post-processing on the sheet bundle accumulated in the stacking unit; an evacuation path that is provided on the other side of the conveying path and receives a sheet conveyed in a reverse direction by a reverse operation of the first conveying roller via the guide portion from a rear end of the sheet when a preceding sheet stack is present in the stacking portion; a second conveying roller that is provided in the evacuation path and that holds the sheet conveyed to the evacuation path and conveys the sheet along the evacuation path; a shift mechanism that shifts at least one of the first conveying roller and the second conveying roller; Equipped with the first conveying rollers overlap the first sheet conveyed by the second conveying rollers from the retreat path with the second sheet received by the receiving section, and convey the sheet to the stacking section by a reverse operation of the first conveying rollers; the shift operation by the shift mechanism includes a first shift operation performed on the first conveyor roller and a second shift operation performed on the second conveyor roller, and the shift operation eliminates the misalignment of the first sheet and the second sheet detected by the detection unit. A post-processing device comprising: (Item 2) 2. The post-processing device according to item 1, wherein the receiving section receives the first sheet and the second sheet following the first sheet. (Item 3) The first shift operation is performed on the first sheet located on the conveying path, and then The first shift operation is performed on the first sheet located in the retreat path, and then the second shift operation is performed for the first sheet. the second shift operation is performed a second time on the first sheet that is positioned on the retreat path after the second shift operation is performed; 3. The post-processing device according to item 2, (Item 4) 4. The post-processing device according to item 3, wherein the first shift operation is performed on the second sheet positioned on the transport path. (Item 5) 5. The post-processing device according to item 4, wherein the second shifting operation for the first sheet and the first shifting operation for the second sheet are performed in parallel. (Item 6) 6. The post-processing device according to item 5, wherein the second shifting operation for the first sheet and the first shifting operation for the second sheet are performed simultaneously. (Item 7) The post-processing device described in any one of items 1 to 6, characterized in that the evacuation path receives the entire length of the sheet in the conveying direction, which has been reverse-conveyed by the reverse operation of the first conveying roller, from the rear end of the sheet via the guide section, and evacuates the sheet. (Item 8) a second guide portion that forms a conveying path together with the first conveying roller and is configured to be able to switch the conveying path of the sheet; a second evacuation path provided on the other side of the conveying path and configured to evacuate the sheet conveyed by the first conveying roller via the second guide portion; 8. The post-processing device according to any one of items 1 to 7, further comprising: (Item 9) 9. The post-processing device according to item 8, wherein when the sheet received by the receiving section is a sheet having a first size in the transport direction, the sheet is evacuated to the second evacuation path. (Item 10) 10. The post-processing device according to item 9, characterized in that if the sheet received by the receiving section is a sheet having a second size smaller than the first size in the transport direction, the sheet is not evacuated to the second evacuation path. (Item 11) 11. The post-processing device according to any one of items 1 to 10, wherein the post-processing is a folding process. (Item 12) 12. The post-processing device according to claim 1, wherein the post-processing includes a plurality of processes. (Item 13) 13. The post-processing device according to any one of items 1 to 12, wherein the receiving section receives a sheet discharged from an image forming device. (Item 14) 14. The post-processing device according to any one of items 1 to 13, further comprising a second post-processing unit different from the post-processing unit, on a downstream side of the transport path. (Item 15) 15. The post-processing device according to any one of items 1 to 14, wherein the transport path is substantially linear. (Item 16) 16. The post-processing device according to any one of items 1 to 15, further comprising a discharge section that discharges the sheet bundle that has been subjected to the post-processing by the post-processing section from the stacking section.

[0154] The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0155] 28 Straight path: 201 Inlet roller: 202, 203 Shift roller: 203 Intermediate conveying roller: 33a Upper flapper: 33b Lower flapper

Claims

1. A receiving section for receiving the sheet; a detection unit that detects a deviation of the sheet received by the receiving unit in a direction perpendicular to a conveying direction; a first conveying roller for conveying the sheet received by the receiving portion; a guide portion that forms a conveying path together with the first conveying roller and is configured to be able to switch the conveying path of the sheet; a stacking unit that is provided on one side of the conveying path and receives the sheet conveyed in a reverse direction by the reverse operation of the first conveying roller via the guide unit, from the rear end of the sheet, and stacks the sheet; a post-processing unit that performs post-processing on the sheet bundle accumulated in the stacking unit; an evacuation path that is provided on the other side of the conveying path and receives a sheet conveyed in a reverse direction by a reverse operation of the first conveying roller via the guide portion, from a rear end of the sheet, when a preceding sheet stack is present in the stacking portion; a second conveying roller that is provided in the evacuation path and that holds the sheet conveyed to the evacuation path and conveys the sheet along the evacuation path; a shift mechanism that shifts at least one of the first conveying roller and the second conveying roller; Equipped with the first conveying rollers overlap the first sheet conveyed by the second conveying rollers from the retreat path with the second sheet received by the receiving unit, and convey the sheet to the stacking unit by a reverse operation of the first conveying rollers; the shift operation by the shift mechanism includes a first shift operation performed on the first conveyor roller and a second shift operation performed on the second conveyor roller, and the shift operation eliminates the misalignment of the first sheet and the second sheet detected by the detection unit. A post-processing device comprising:

2. The post-processing device according to claim 1 , wherein the receiving section receives the first sheet and the second sheet following the first sheet.

3. The first shift operation is performed on the first sheet located on the conveying path, and then The first shift operation is performed on the first sheet located on the retreat path, and then the second shift operation is performed for the first sheet. a second shift operation is performed on the first sheet that is positioned on the retraction path after the second shift operation is performed; The post-processing device according to claim 2 .

4. 4. The post-processing device according to claim 3, wherein the first shift operation is performed on the second sheet positioned on the transport path.

5. 5. The post-processing device according to claim 4, wherein the second shifting operation for the first sheet and the first shifting operation for the second sheet are performed in parallel.

6. 6. The post-processing device according to claim 5, wherein the second shifting operation for the first sheet and the first shifting operation for the second sheet are performed simultaneously.

7. 2 . The post-processing device according to claim 1 , wherein the evacuation path receives the entire length of the sheet in the conveying direction, which is reversely conveyed by the reverse operation of the first conveying roller, from the rear end of the sheet via the guide portion, and evacuates the sheet.

8. a second guide portion that forms a conveying path together with the first conveying roller and is configured to be able to switch the conveying path of the sheet; a second evacuation path provided on the other side of the conveying path and configured to evacuate the sheet conveyed by the first conveying roller via the second guide portion; The post-processing device according to claim 1 , further comprising:

9. 9. The post-processing device according to claim 8, wherein when the sheet received by the receiving unit has a first size in the transport direction, the sheet is retreated to the second retreat path.

10. 10. The post-processing device according to claim 9, wherein when the sheet received by the receiving unit has a second size smaller than the first size in the transport direction, the sheet is not evacuated to the second evacuation path.

11. The post-processing device according to claim 1 , wherein the post-processing is a folding process.

12. The post-processing device according to claim 1 , wherein the post-processing includes a plurality of processes.

13. The post-processing device according to claim 1 , wherein the receiving section receives the sheet discharged from an image forming device.

14. The post-processing device according to claim 1 , further comprising a second post-processing unit different from the post-processing unit, disposed downstream of the transport path.

15. The post-processing device according to claim 1 , wherein the transport path is substantially linear.

16. The post-processing apparatus according to claim 1 , further comprising a discharge section that discharges the sheet bundle that has been subjected to the post-processing by the post-processing section from the stacking section.

Images