Post-processing device, image forming apparatus, and image forming system

Abstract

To provide a post-processing device capable of suppressing deterioration of processing property of transportation failure of a sheet, even when having a transportation route correction structure for improving overlapping accuracy of sheet end parts.SOLUTION: A post-processing device has: first transportation means for transporting sheets transported along a first transporting route to the downward side; second transportation means for transporting the sheets along a second transporting route; and third transportation means for transporting the sheets along a third transporting route. The sheets are circulated in the order of the first, second and third transportation routes, and the multiple sheets are overlapped. A transportation route correction member is provided for directing a transportation direction of the sheets transported from a circulation route to the first transportation means, when joining from the third transportation route to the first transportation route. The transportation route correction member has a retreating mechanism allowing retreating from a joining position where the third transportation route joins to the first transportation route.SELECTED DRAWING: Figure 18

Description

Technical Field

[0001] The present invention relates to a post-processing device, an image forming apparatus including the post-processing device, and an image forming system.

Background Art

[0002] There is known a post-processing device that performs alignment processing for stacking a plurality of sheets, which are sheet-like media, with their ends aligned, folding processing for folding the stacked plurality of sheets, and the like. Further, in an image forming apparatus that forms an image on a sheet, an image forming apparatus including a post-processing mechanism for the sheet on which the image has been formed, and an image forming system in which a post-processing device and an image forming apparatus are connected are also known.

[0003] In a post-processing device that abuts the leading end in the sheet conveyance direction against a conveyance roller to align and stack a plurality of sheets and then performs folding processing on the stacked sheets, a configuration including a circulation path is disclosed (see Patent Document 1).

Summary of the Invention

Problems to be Solved by the Invention

[0004] The circulation path disclosed in Patent Document 1 branches from the downstream of a folding conveyance member that performs folding processing, circulates and conveys the sheet to the upstream side of the folding conveyance member, and is configured to overlap with a subsequent sheet.

[0005] In the configuration according to this prior art, when a subsequent sheet is abutted against a conveyance roller for conveying the sheet to the folding conveyance member and the subsequent sheet is bent, the preceding sheet that has circulated and returned will travel along the bent subsequent sheet toward the conveyance roller. In this case, compared with when the subsequent sheet is not bent, the conveyance length of the preceding sheet becomes longer, and the conveyance gap between the preceding sheet and the subsequent sheet increases.

[0006] Patent Document 1 does not consider a configuration for preventing an increase in the conveyance gap caused by the bending of the subsequent sheet, nor is there a suggestive disclosure. Therefore, in the prior art, there is a problem in suppressing the "shift" in the superposition of a plurality of sheets using a circulation path.

[0007] To address this problem, a configuration for correcting the conveyance path of the preceding sheet may be provided. However, since it is necessary to provide such a configuration in the vicinity where the circulation path and the loading path merge, if a conveyance failure such as a sheet jam occurs in the vicinity of the merge, the configuration for correcting the conveyance path will interfere with the removal of the sheet. That is, it becomes a factor for reducing the processability of conveyance failures.

[0008] An object of the present invention is to provide a post-processing apparatus that can suppress a decrease in the processability of sheet conveyance failures even when provided with a conveyance path correction structure for improving the superposition accuracy of sheet ends.

Means for Solving the Problem

[0009] To solve the above technical problem, one aspect of the present invention includes first conveyance means for conveying a sheet being conveyed along a first conveyance path downstream, second conveyance means for conveying the sheet along a second conveyance path, and third conveyance means for conveying the sheet along a third conveyance path, and is a post-processing apparatus for circulating the sheet in the order of the first conveyance path, the second conveyance path, and the third conveyance path to superpose a plurality of sheets, and includes a conveyance path correction member for directing the conveyance direction of the sheet conveyed from the circulation path toward the first conveyance means when merging from the third conveyance path to the first conveyance path, and the conveyance path correction member has a retraction mechanism that can retract from a merge position where it merges from the third conveyance path to the first conveyance path.

Effects of the Invention

[0010] According to the present invention, even when provided with a conveyance path correction structure for improving the superposition accuracy of sheet ends, a decrease in the processability of sheet conveyance failures can be suppressed.

Brief Description of the Drawings

[0011]

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Mode for Carrying Out the Invention

[0012] [Embodiment of Image Forming Apparatus] First, an embodiment of the image forming apparatus according to the present invention will be described. FIG. 1 is an external view of a printer 10 as an image forming apparatus. The printer 10 includes a printer unit 100 as an image forming unit and a post-processing device such as a folding processing unit 200 that can be connected to the printer unit 100. As shown in FIG. 1, the printer 10 is of an in-body discharge type, and has a configuration in which the folding processing unit 200 is incorporated into a part of the printer unit 100. In the printer 10, the folding processing unit 200 can be selected as the discharge destination of a recording medium (sheet P) on which an image has been formed. The internal configuration of the folding processing unit 200 will be described later.

[0013] [Embodiment of Image Forming System] FIG. 2 is a diagram showing a schematic configuration of a printer system 1 as an embodiment of an image forming system according to the present invention. In FIG. 2, the printer system 1 is configured by connecting a printer 100a and a folding processing device 200a as a post-processing device. The printer system 1 operates such that a sheet P on which an image is formed by the printer 100a is conveyed to the folding processing device 200a, and predetermined folding processing is performed in the folding processing device 200a.

[0014] [Functional Configuration of Control Block] Next, an embodiment of a control block that controls the operations of the printer unit 100 and the folding processing unit 200 according to the present embodiment will be described with reference to FIG. 3. As shown in FIG. 3, the printer unit 100 includes a printer control unit 110 as a control block. The printer control unit 110 includes a CPU (Central Processing Unit) 1 11, a ROM (Read Only Memory) 1 12, a RAM (Random Access Memory) 1 13, and a serial I / F 114.

[0015] An image creation unit 120, an image reading unit 130, and an operation display unit 140 are connected to the printer control unit 110. The image creation unit 120, the image reading unit 130, and the operation display unit 140 each include a configuration for exerting their respective functions. Each configuration included in the image creation unit 120, the image reading unit 130, and the operation display unit 140 operates based on a control signal from the printer control unit 110.

[0016] The image creation unit 120 is configured to perform an image forming process based on image data on a sheet P as a sheet-like recording medium. The image reading unit 130 is configured to read an image formed on the sheet P and acquire image data. The operation display unit 140 has a function that serves as an input unit for inputting operation conditions in the image creation unit 120 and the image reading unit 130 and a display unit for displaying operation results and the like.

[0017] A control program for controlling the image creation unit 120, the image reading unit 130, and the operation display unit 140 is stored in the ROM 112. The CPU 111 reads out the control program stored in the ROM 112 and expands it in the RAM 113. Then, the CPU 111 stores data necessary for control in the RAM 113 and executes the control defined by the control program while using the RAM 113 as a work area.

[0018] Also, as shown in FIG. 3, the folding processing unit 200 includes a post-processing control unit 210 as a control block. The post-processing control unit 210 includes a CPU 211, a ROM 212, a RAM 213, and a serial I / F 214.

[0019] Various loads 220 and various sensors 240 are connected to the post-processing control unit 210. The various loads 220 are rollers and roller pairs described later. The rollers and roller pairs corresponding to the various loads 220 respectively constitute a conveyance roller pair and a folding roller pair. The various loads 220 are operated by drive motors that rotationally drive each roller and each roller pair. The drive motors constituting the various loads 220 are operated by a driver 230 that receives an instruction from the post-processing control unit 210. The various loads 220 are configured to perform operations including conveyance control of the sheet P as a recording medium and folding processing on the sheet P.

[0020] The various sensors 240 are a plurality of sheet detection means for detecting the position within the conveyance path of the sheet P, and are arranged in plurality within the conveyance path described later. The conveyance amount and position of the sheet P to be post-processed are determined by the post-processing control unit 210 processing according to a predetermined control program based on the detection signal output by the various sensors 240 toward the post-processing control unit 210. Note that the position of the sheet P can be calculated by the post-processing control unit 210 based on the operation amount of the various loads 220 of the conveyance amount (conveyance distance) of the sheet P since the leading edge of the sheet P is detected by the sheet detection means.

[0021] The control program for the post-processing control unit 210 to execute a predetermined processing function is stored in the ROM 212. The CPU 211 reads out the control program stored in the ROM 212 and expands it in the RAM 213. Then, the CPU 211 stores the data necessary for control in the RAM 213 and executes the control of the folding operation defined by the control program while using the RAM 213 as a work area. As described above, by executing the control program stored in the ROM 212 by the post-processing control unit 210, it is possible to perform the detection of the sheet P and the conveyance control of the sheet P, which will be described later.

[0022] The printer control unit 110 included in the printer unit 100 and the post-processing control unit 210 included in the folding processing unit 200 are communicably connected via the serial I / F 114 and the serial I / F 214. Using this communication path, control commands and information necessary for the conveyance control of the recording medium and the like are exchanged. The folding processing unit 200 switches the conveyance control of the recording medium, the presence or absence of the folding process, and the type of the folding process based on the control commands and information regarding the sheet P sent from the printer unit 100 and the information regarding the position of the recording medium obtained from the various sensors 240.

[0023] Note that the information regarding the sheet P sent from the printer unit 100 (printer control unit 110) to the folding processing unit 200 (post-processing control unit 210) includes a plurality of information. For example, it includes a plurality of sheet type information indicating the type of the sheet P, the thickness of the sheet P, the size of the sheet P, etc., which are transferred from the printer unit 100 to the folding processing unit 200. Further, the information also includes information indicating the designation of the stacking quantity regarding the sheet P, the type of the folding process for the sheet P, and the presence or absence of an image at the folding position of the sheet P. And the control commands notified from the printer control unit 110 to the post-processing control unit 210 also include whether the sheet P to be transferred corresponds to the last page (final sheet) of the unit in which the sheet P is processed in a grouped manner.

[0024] [Embodiment of the Post-Processing Device] Next, as the first embodiment of the post-processing apparatus according to the present invention, the internal configuration of the folding processing unit 200 will be described. FIG. 4 is a configuration diagram schematically showing the internal configuration of the folding processing unit 200. The folding processing unit 200 includes a plurality of conveyance paths, a plurality of roller pairs for conveying the sheet P in each conveyance path and performing folding processing, and a plurality of sheet detection sensors for detecting the conveyance position of the sheet P. Note that each of the plurality of roller pairs constitutes a conveyance means or a folding means.

[0025] The conveyance paths included in the folding processing unit 200 are roughly classified into seven. As shown in FIG. 4, it includes a first conveyance path W1, a second conveyance path W2, a third conveyance path W3, a fourth conveyance path W4, a fifth conveyance path W5, a sixth conveyance path W6, and a seventh conveyance path W7.

[0026] And a plurality of roller pairs are arranged along each of the first conveyance path W1, the second conveyance path W2, the third conveyance path W3, the fourth conveyance path W4, the fifth conveyance path W5, and the sixth conveyance path W6. That is, roller pairs constituting the zero-th conveyance means R0, the first conveyance means R1, the second conveyance means R2, the third conveyance means R3, the fourth conveyance means R4, the fifth conveyance means R5, and the sixth conveyance means R6 are arranged at their respective positions on the conveyance path for conveying the sheet P. The rotation start and rotation stop of each conveyance roller pair as these conveyance means are controlled by a control program executed by the post-processing control unit 210. By this control, the conveyance start and conveyance stop of the sheet P are executed.

[0027] Further, the folding processing unit 200 includes a plurality of conveyance branching means. The plurality of conveyance branching means switches, for example, between a state of conveying the sheet P from the first conveyance path W1 to the second conveyance path W2 and a state of conveying the sheet P conveyed to the second conveyance path W2 in a direction of returning it to the first conveyance path W1. Also, while returning from the second conveyance path W2 to the first conveyance path W1, it switches to a state of conveying to the third conveyance path W3 and conveying to a circulation conveyance path for circulating the sheet P.

[0028] In addition, the conveyance diverting means executes switching so as to convey the sheet P to the fourth conveyance path downstream of the second conveyance path without circulating it through the circulation conveyance path.

[0029] In addition, the conveyance diverting means executes switching so as to convey the sheet from the first conveyance path W1 through the third conveyance path W3 to the fifth conveyance path downstream of the second conveyance path. A plurality of conveyance diverting means are arranged in the folding processing unit 200 so as to execute switching of these conveyance paths.

[0030] The plurality of conveyance diverting means are configured as a first conveyance diverting means J1, a second conveyance diverting means J2, and a third conveyance diverting means J3, as shown in FIGS. 5 to 14, for example. These plurality of conveyance diverting means are included in various loads 220 whose operations are controlled by the post-processing control unit 210. Therefore, the post-processing control unit 210 controls the conveyance path of the sheet P by controlling the operations of the plurality of conveyance diverting means. Note that a first folding means F1 and a second folding means F2 for performing a folding process on the sheet P are also arranged in the middle of the circulation conveyance path.

[0031] In the vicinity of the inlet 21 where the folding processing unit 200 receives the sheet from the printer unit 100, a zero-th conveyance means R0 as an inlet conveyance roller pair is arranged. After receiving information indicating that the printer unit 100 has discharged the sheet P, the drive motor that rotationally drives the zero-th conveyance means R0 starts rotating under the control of the post-processing control unit 210. Then, when the leading edge of the sheet P reaches the nip of the roller pair of the zero-th conveyance means R0, the zero-th conveyance means R0 conveys the sheet P to the downstream side.

[0032] As will be described later, before discharging the sheet P carried in from the printer unit 100 from the downstream outlet 22, the folding processing unit 200 accepts the next sheet P and performs conveyance processing and folding processing in which the previous sheet P and the subsequent sheet P are overlapped. Therefore, in the following description, for the sake of explanation, the preceding sheet P is denoted as "preceding sheet P1". Also, the sheet P that follows the preceding sheet P1 and is accepted by the folding processing unit 200 after the preceding sheet P1 is denoted as "subsequent sheet P2". And the sheet P that is accepted by the folding processing unit 200 next after the subsequent sheet P2 and is the target of the overlapping process is denoted as "next sheet P3". Also, a plurality of sheets obtained by overlapping a plurality of sheets P are denoted as "sheet bundle Q".

[0033] Note that the number of sheets P when performing the overlapping process or the folding process in the folding processing unit 200 is not limited to three, and more sheets can also be processed.

[0034] The first conveyance means R1 consists of a pair of rollers facing each other across the first conveyance path W1, and forms a nip between the rollers. The first folding means F1 is disposed opposite between the first conveyance path W1 and the second conveyance path W2, and forms a nip therebetween. The path guided by this nip guides the preceding sheet P1 from the first conveyance path W1 to the second conveyance path W2.

[0035] Furthermore, the third conveyance means R3 guides the preceding sheet P1 guided to the second conveyance path W2 to the third conveyance path W3 and temporarily stops the conveyance of the preceding sheet P1 on the third conveyance path W3. The preceding sheet P1 temporarily stopped on the third conveyance path W3 is restarted when the subsequent sheet P2 is received from the printer unit 100. As a result, the preceding sheet P1 returns upstream of the first conveyance means R1 of the first conveyance path W1 and merges with the subsequent sheet P2. The circulation conveyance path is configured as described above.

[0036] In the circulation conveyance path described above, the preceding sheet P1 and the subsequent sheet P2 are overlapped to form a sheet bundle Q. Subsequently, the flow when performing the folding process on the sheet bundle Q will be described.

[0037] The folding process for the sheet bundle Q is performed by a first folding means F1 that operates under the control of a post-processing control unit 210. Then, the sheet bundle Q on which the folding process has been performed by the first folding means F1 is transferred from the second conveyance path W2 to the fifth conveyance path W5. The fourth conveyance means R4, the fifth conveyance means R5, and the first folding means F1 are driven by the same drive motor. The drive motor can rotate in both forward and reverse directions, and by changing the rotation direction, it conveys the sheet bundle Q formed by overlapping the preceding sheet P1 and the subsequent sheet P2 and also performs the folding process.

[0038] Also, a branching claw 23 is arranged immediately after the sixth conveyance means R6. The branching claw 23 switches the guide position when guiding the sheet P (sheet bundle Q) to the sixth conveyance path W6 side and when guiding the sheet P (sheet bundle Q) to the seventh conveyance path W7 side. The branching claw 23 can switch its position by, for example, a solenoid. Note that a drive mechanism including a motor, gears, cams, etc. can also be used instead of the solenoid.

[0039] The sheet P that has passed through the fourth conveyance path W4 or the fifth conveyance path W5 is discharged and stacked on the discharge tray 24 of the folding unit 200. The seventh conveyance path W7 is a path for transferring the sheet P to a post-processing device when a post-processing device is provided downstream of the folding unit 200 as an image forming system. In the post-processing device, post-processing such as alignment processing and binding processing is performed on the sheet P that has been folded or the sheet P that has not been folded.

[0040] Immediately after the zero-th conveying means R0 of the first conveying path W1, a first sheet detection sensor SN1 is arranged. Immediately before the first conveying means R1, a second sheet detection sensor SN2 is arranged. Immediately after the second conveying means R2 in the third conveying path W3, a third sheet P detection sensor SN3 is arranged. Immediately after the third conveying means R3 in the third conveying path W3, a fourth sheet detection sensor SN4 is arranged. Immediately after the fourth conveying means R4 in the fourth conveying path W4, a fifth sheet detection sensor SN5 is arranged. Immediately after the fifth conveying means R5 in the fifth conveying path W5, a sixth sheet P detection sensor SN6 is arranged. Immediately after the sixth conveying means R6 in the sixth conveying path W6, a seventh sheet detection sensor SN7 is arranged.

[0041] [Example of stacking operation] By the folding processing unit 200 illustrated in FIG. 4, the sheet P can be folded in three inside and three outside in a stacked state. FIGS. 5 to 10 will describe a series of operations for generating a sheet bundle Q by stacking two sheets P via a circulating conveying path.

[0042] FIG. 5 shows an initial state before the sheet P is conveyed from the printer unit 100 side. In the state of FIG. 5, at the point where the leading end of the preceding sheet P1 conveyed from the printer unit 100 side reaches the paper discharge port of the printer unit 100, the post-processing control unit 210 starts the rotation of the zero-th conveying means R0.

[0043] By the rotation of the zero-th conveying means R0, as shown in FIG. 6, the preceding sheet P1 is conveyed to the first conveying path W1. Further, in order to convey the preceding sheet P1 to the second conveying path W2 instead of the fourth conveying path W4 and guide it to the circulating conveying path, the post-processing control unit 210 moves the first conveying branch means J1 to the position shown in FIG. 6.

[0044] When the tip of the preceding sheet P1 conveyed by the zero-th conveying means R0 is detected by the first sheet detection sensor SN1, a detection signal is notified to the post-processing control unit 210. Then, after receiving the detection signal, the post-processing control unit 210 calculates the timing at which the leading protrusion amount of the sheet P reaches a predetermined value from the nip position of the first conveying means R1. Note that the protrusion out amount of the leading edge of the sheet P from the nip position of the first conveying means R1 is referred to as "first protrusion out amount Δ1". At the timing when the first protrusion out amount Δ1 is reached, the rotation of the first conveying means R1 is started.

[0045] When the tip of the preceding sheet P1 enters the nip of the first conveying means R1, the post-processing control unit 210 rotates the first folding means F1, the second conveying means R2, and the third conveying means R3.

[0046] Then, as shown in FIG. 7, the preceding sheet P1 is conveyed to the second conveying path W2 by the operation of the first conveying means R1, and is further conveyed to the second conveying means R2 along the slope of the downward gradient of the second conveying path W2, and is conveyed to the third conveying path W3 by the operation of the second conveying means R2. When the tip of the preceding sheet P1 is detected by the fourth sheet detection sensor SN4, a detection signal is notified from the fourth sheet detection sensor SN4 to the post-processing control unit 210. Therefore, after receiving the detection signal, the post-processing control unit 210 calculates the timing from when the preceding sheet P1 is conveyed until its tip reaches a position corresponding to the second protrusion amount Δ2 from the position of the fourth sheet detection sensor SN4.

[0047] As shown in FIG. 8, when it is determined that the leading edge of the preceding sheet P1 has reached a position corresponding to the second protrusion amount Δ2, the rotation of the first folding means F1, the second conveying means R2, and the third conveying means R3 is stopped, and the conveyance of the preceding sheet P1 is stopped.

[0048] Note that even when the conveyance of the preceding sheet P1 is stopped, in order to receive the subsequent sheet P2 conveyed from the printer unit 100 next, the rotation of the first conveying means R1 is kept continuous.

[0049] Subsequently, as shown in FIG. 9, after the detection signal indicating that the leading edge of the subsequent sheet P2 has been detected by the first sheet detection sensor SN1 is notified, while conveying the subsequent sheet P2, the conveyance of the preceding sheet P1 is resumed at the timing calculated from the detection of the first sheet detection sensor SN1, and the subsequent sheet P2 is conveyed while being overlapped with the preceding sheet P1 in a state where it slightly precedes the preceding sheet P1. This timing corresponds to the timing until the subsequent sheet P2 reaches a position corresponding to the third protrusion amount Δ3 when the leading edge of the subsequent sheet P2 merges with the preceding sheet P1. Then, when the leading edge of the subsequent sheet P2 reaches a position corresponding to the third protrusion amount Δ3, the rotation of the second conveying means R2 and the third conveying means R3 is resumed. As a result, as shown in FIG. 9, the conveyance of the preceding sheet P1 that had been stopped is resumed.

[0050] That is, without stopping the subsequent sheet P2, while conveying the subsequent sheet P2, the "timing" is calculated from the detection of the first sheet detection sensor SN1. At the calculated timing, the conveyance of the preceding sheet P1 is resumed. By this control, the subsequent sheet P2 is conveyed while being overlapped with the preceding sheet P1 in a state where it slightly precedes the preceding sheet P1.

[0051] Note that the third protrusion amount Δ3 is calculated based on the motor speeds of the zero conveying means R0 and the third conveying means R3, and the distances of the first sheet detection sensor SN1, the second sheet detection sensor SN2, and the fourth sheet detection sensor SN4. The third protrusion amount Δ3 is also for forming a displacement amount when the leading edges of the preceding sheet P1 and the subsequent sheet P2 merge in front of the first conveying means R1.

[0052] Then, the leading edge of the preceding sheet P1 and the leading edge of the subsequent sheet P2 merge, and a sheet bundle Q is generated, and as shown in FIG. 10, it passes through the nip of the first conveying means R1 and is conveyed downstream. As described above, control is performed such that the subsequent sheet P2 first hits the nip of the first conveying means R1, and then the preceding sheet P1 hits the nip of the first conveying means R1. As a result, when the third protrusion amount Δ3 is large, even if they have not yet merged in front of the second sheet detection sensor SN2, the merging timing can be adjusted.

[0053] After that, the post-processing control unit 210 determines whether the number of stacked sheets set notified from the printer unit 100 matches the number of received sheets. If they match, the folding process described below is performed. If they do not match, the processes from FIG. 7 to FIG. 9 are performed again, and the next sheet P3 (the sheet P next to the subsequent sheet P2) conveyed from the printer unit 100 side is merged with the sheet bundle Q and stacked. Note that whether the sheet P has been conveyed to just before the nip of the second conveying means R2 can be determined, for example, from the number of drive steps of the motor that drives the first conveying means R1. Therefore, a drive motor that rotationally drives each conveying means may be a stepping motor or the like. Note that a DC motor can also be applied if control is performed based on the timing calculated by detection of each sensor.

[0054] [Embodiment of Folding Process] Next, the flow of the folding process in the folding process unit 200 according to the present embodiment will be described. FIGS. 11 to 14 are operation explanatory diagrams for triple-fold folding the sheet bundle Q received from the upstream.

[0055] As described with reference to FIG. 10, the merged sheet bundle Q is conveyed as it is by the zeroth conveying means R0 and the first conveying means R1. Then, when the leading end of the sheet bundle Q enters the nip of the first conveying means R1, the sheet bundle Q is conveyed toward the fourth conveying means R4 side.

[0056] When the post-processing control unit 210 is conveyed to just before the nip of the fourth conveying means R4, it drives the motor and rotates the first conveying means R1 and the fourth conveying means R4 in the direction of the arc arrow in FIG. 11. The leading end of the sheet bundle Q is conveyed from the point where it is detected by the fifth sheet detection sensor SN5 until the leading end reaches the fourth protrusion amount Δ4.

[0057] Thereafter, while rotating the first conveying means R1 in the conveying direction, the post-processing control unit 210 reversely rotates the fourth conveying means R4 (first folding means F1) to convey the sheet bundle Q in the direction opposite to the conveying direction shown in FIG. 7 (see FIG. 12). Due to the reverse rotation of the fourth conveying means R4, the sheet bundle Q is conveyed in the reverse direction.

[0058] On the other hand, as shown in FIG. 13, the first conveying means R1 rotates in the direction continued from the state shown in FIG. 9 and conveys the sheet bundle Q. As a result, a bend is formed in front of the nip of the first folding means F1. This bend enters the nip and the first folding is performed, forming the first fold line.

[0059] The sheet bundle Q subjected to the first folding is conveyed to the second conveying path W2 and conveyed along the slope of the downward gradient of the second conveying path W2. The sheet bundle Q is conveyed from the point where the leading end of the sheet bundle Q is detected by the third sheet P detection sensor SN3 until the leading end of the sheet P reaches the fifth protruding amount Δ5.

[0060] Thereafter, while the post-processing control unit 210 rotates the fourth conveying means R4 (first folding means F1) in the conveying direction, the second conveying means R2 is reversely rotated with respect to the rotation direction shown in FIG. 13. Due to the reverse rotation of the second conveying means R2, the sheet P is conveyed in the reverse direction. On the other hand, the post-processing control unit 210 rotates the fourth conveying means R4 (first folding means F1) in the direction continued from FIG. 13 to convey the sheet P. As a result, as shown in FIG. 14, a bend is formed in front of the nip of the fifth conveying means R5 (second folding means F2). Then, this bend enters the nip and the second folding is performed, forming the second fold line.

[0061] The sheet bundle Q subjected to the second folding passes through the fifth conveying path W5 and is conveyed to the discharge tray 24. The fourth protruding amount Δ4 and the fifth protruding amount Δ5 are determined based on the total length of the sheet P and the folding method set for the sheet P (sheet bundle Q). Then, the post-processing control unit 210 determines the fourth protruding amount Δ4 and the fifth protruding amount Δ5 based on this setting by the rotation amount (the number of drive steps of the drive motor) of the second conveying means R2.

[0062] In the case of an outer three - fold, the first fold is made at a position corresponding to 1 / 3 of the full length of the sheet P from the leading end in the conveyance direction of the sheet P. Then, the second fold is made at a position corresponding to 1 / 3 of the full length of the sheet P on the opposite side. In the case of an inner three - fold, the first fold is made at a position corresponding to 2 / 3 of the full length of the sheet P from the leading end of the sheet P in the conveyance direction, and the second fold is made at a position 1 / 3 of the full length on the opposite side.

[0063] Thereafter, the sheet bundle Q on which the second fold has been made is conveyed downstream by the fifth conveying means R5 via the fifth conveying path W5.

[0064] [Comparative Example] Here, in order to clarify the features of the embodiment according to the present invention, an example of the folding processing unit 200 not provided with a conveyance path correction member is shown in FIG. 15. Using the comparative example shown in FIG. 15, the problems caused by not providing a conveyance path correction member will be explained.

[0065] FIG. 15(a) illustrates a state in which the subsequent sheet P2 is first abutted against the first conveying means R1 in order to overlap the preceding sheet P1, and the preceding sheet P1 circulates through the first conveying path via the circulation conveying path. W1 The circle M in the figure indicates the vicinity of the confluence point of the loading path and the circulation path.

[0066] The subsequent sheet P2 is conveyed by the zero - th conveying means R0 while being abutted against the first conveying means R1 until the preceding sheet P1 converges. Here, as shown in FIG. 15(b), assume an example where the subsequent sheet P2x does not bend inside the first conveying path, as an example of an ideal conveying state. In this case, the preceding sheet P1x abuts against the subsequent sheet P2x at the position of the circle M and passes through the ideal conveying path. Thereafter, the subsequent sheet P2 x is conveyed to the first conveying means R1 along the subsequent sheet P2 x The overlapping of the preceding sheet P1x and the subsequent sheet P2

[0067] However, in reality, as shown in FIG. 15(c), the subsequent sheet P of 2 is bent within the first conveyance path W1, so the leading sheet P1 does not contact the subsequent sheet P2 at the position of the circle M, and the conveyance length becomes longer compared to the leading sheet P1x passing through the ideal conveyance path. In this case, since the conveyance path length of the leading sheet P1 becomes longer compared to the ideal conveyance state, the conveyance gap with the subsequent sheet P2 will increase.

[0068] As a result, when the leading sheet P1 and the subsequent sheet P2 are overlapped, the ends are displaced, and then, in the subsequent folding process, the folded sheet is in a state where the ends are displaced.

[0069] In the folding processing unit 200 according to the present embodiment described below, by providing a conveyance path correction member that suppresses the above-described conveyance gap, the accuracy of overlapping a plurality of sheets P can be improved.

[0070] [First Embodiment of Conveyance Path Correction Unit] FIG. 16 illustrates a path correction unit 250 as a conveyance path correction member included in the folding processing unit 200 according to the present embodiment. The path correction unit 250 is disposed at the position of the circle M that has already been described, that is, at the confluence position of the carry-in path and the circulation path. By providing the path correction unit 250, the conveyance gap as described using the comparative example can be suppressed, so that the displacement of overlapping a plurality of sheets P can be suppressed.

[0071] As illustrated in FIG. 16(a), the path correction unit 250 is disposed at a position where it can correct the conveyance direction after the leading edge of the preceding sheet P1 being circulated and conveyed enters the first conveyance path W1 so as to be directed toward the first conveyance means R1. For example, when the sheet P circulates from the third conveyance path W3 to the first conveyance path W1, the conveyance directions of the preceding sheet P1 and the subsequent sheet P2 interfere with each other in the vicinity of the confluence point. In the process of stacking a plurality of sheets P, when the conveyance directions of the plurality of sheets P interfere with each other, it is necessary to correct the conveyance direction of each individual sheet P at the interference position to an ideal direction. Therefore, the path correction unit 250 in the present embodiment includes a plate-like member that protrudes downstream in the conveyance direction from the joint portion of the guide plate constituting the third conveyance path W3 and the guide plate constituting the first conveyance path W1.

[0072] When the leading edge of the circulated and conveyed preceding sheet P1 abuts against the plate-like member of the path correction unit 250, the direction along the surface direction of the plate-like member becomes the conveyance direction direction of the preceding sheet P1. The surface direction at this time is the direction toward the first conveyance means R1 and corresponds to the downstream direction in the conveyance direction.

[0073] Therefore, as shown in FIG. 16(b), the plate-like member provided in the path correction unit 250 corrects the conveyance direction of the preceding sheet P1 so as to be directed toward the first conveyance means R1 in the vicinity of the confluence position with the circulation path where the preceding sheet P1 returns.

[0074] As a result, as shown in FIG. 16(c), even if the subsequent sheet P2 is bent in a state of being abutted against the first conveyance means R1, the conveyance path of the preceding sheet P1 is corrected and can be abutted against the first conveyance means R1 in the same manner as the subsequent sheet P2. As a result, the accuracy of overlapping the ends of the plurality of sheets P can be improved.

[0075] Next, with reference to FIG. 17, a further problem that is assumed to occur by providing the path correction unit 250 will be described. FIG. 17 illustrates a case where the subsequent sheet P2 has a conveyance failure (when a jam occurs) while being conveyed to the first conveyance means R1 via the first conveyance path W1 as an incoming path. In order to eliminate the jam, it is necessary to remove the subsequent sheet P2 that has become a conveyance failure.

[0076] As illustrated in FIG. 17(a), a guide plate 260 that forms a part of the wall surface connecting the third conveyance path W3 to the first conveyance path W1 is configured to rotate. By rotating this guide plate 260, an opening is formed that allows access to the first conveyance path W1 from the outside. The user can perform a process of pulling out and removing the sheet P remaining as a conveyance failure through the opening.

[0077] However, as illustrated in FIG. 17(b), in order to pull out the subsequent sheet P2 in the processing direction S, it is necessary to access a space for pulling out the subsequent sheet P2 (that is, a space near the confluence point of the first conveyance path W1 and the third conveyance path W3). However, the arrangement of the path correction unit 250 in this space obstructs the removal process. In particular, as the path correction unit 250, a plate-like member protruding toward the confluence point side narrows the processing space for the subsequent sheet P2. Therefore, the processability of the process of pulling out the subsequent sheet P2 from the portion of the guide plate 260 is reduced.

[0078] As described above, when the path correction unit 250 is provided, the accuracy of superposition increases because the preceding sheet P1 can be conveyed as intended, while the processability of the removal process of the subsequent sheet P2 at the time of jam occurrence decreases. In this regard, the path correction unit 250 according to the present embodiment can solve the above-assumed problems.

[0079] FIG. 18 illustrates the operation of the correction guide plate 251 included in the path correction unit 250 according to the present embodiment. FIG. 18(a) illustrates a state in which the guide plate 260 is rotated outward of the first conveyance path W1 to provide an opening in the first conveyance path W1 to enable access to the inside. By setting the state shown in FIG. 18(a), it is possible to access the sheet P that has a conveyance defect inside and pull and remove the sheet P in the processing direction S.

[0080] The correction guide plate 251 is configured such that its tip rotates in the direction of the processing direction S by the tensile force when removing the subsequent sheet P2. The correction guide plate 251 is normally biased in the direction opposite to the processing direction S and guides the sheet P conveyed on the carry-in path to the first conveying means R1. That is, when a force is applied in the processing direction S and the tensile force becomes greater than the above-described biasing force, as illustrated in FIG. 18(a), the correction guide plate 251 is pulled by the subsequent sheet P2 and moves in the direction of retracting from the processing space. That is, when performing the process of removing the sheet P from the conveyance path, the path correction unit 250 has a retracting mechanism that can retract from the conveyance path according to the force applied by the processing direction. This retracting mechanism is effective particularly in the retraction of the correction guide plate 251 from the confluence position where the third conveyance path W3 merges into the first conveyance path W1 when a conveyance defect of the sheet P occurs.

[0081] After that, when the subsequent sheet P2 is removed, the force applied to the correction guide plate 251 disappears, so it returns to its original state.

[0082] One end of an elastic member is fixed to the end portion on the downstream side in the conveyance direction of the correction guide plate 251, and the other end of this elastic member is fixed to the housing of the folding processing unit 200, and the correction guide plate 251 is biased in the direction opposite to the processing direction S.

[0083] Therefore, as shown in Fig. 18(a), when a jam occurs, the correction guide plate 251 rotates due to the force that pulls the sheet P (the subsequent sheet P2) in the processing direction (removal direction), and stays at a position retracted from the removal process during processing. Then, when the removal of the subsequent sheet P2 is completed, it rotates back to the original state as illustrated in Fig. 18(b) by the biasing of the elastic member.

[0084] Next, an example of the detailed structure of the path correction unit 250 will be described. Fig. 19 is a perspective view of the path correction unit 250 as seen obliquely from the front in the X direction orthogonal to the Y direction, which is the conveyance direction of the sheet P, that is, in the width direction of the sheet P. As illustrated in Fig. 19, the path correction unit 250 includes a correction guide plate 251, an elastic material part 252, and a first biasing member 253.

[0085] The correction guide plate 251 has a plate member 2511 corresponding to a plate-like member that corrects the conveyance direction of the preceding sheet P1 conveyed along the circulation path to the direction of the first conveyance means R1 (Y direction), and a plate holding part 2512 for holding the plate member 2511 at a predetermined position. In the plate holding part 2512, there is a rib that stands up from the X-direction end of the plate member 2511 toward the Z direction, and a shaft hole 2 5 13 is provided for rotatably holding the plate member 2511.

[0086] The elastic material part 252 as an elastic member installed on the plate member 2511 is a plate-like member installed at the downstream end of the plate member 2511 in the conveyance direction and is made of a material softer than the plate member 2511. This elastic material part 252 is an elastic member deformable in the vertical direction with respect to the conveyance direction. The flexibility of the elastic material part 252 only needs to be deformable in a direction orthogonal to the conveyance direction of the sheet P by an external force applied in the processing direction for removing the sheet P when a jam occurs. And it only needs to have elasticity to return to the original position when the external force applied in the processing direction disappears.

[0087] The first biasing member 253 has one end fixed to the end of the plate member 2511 and the other end fixed to the housing of the folding processing unit 200 or the like. The first biasing member 253 is a biasing member that applies a biasing force to pull up the downstream end of the plate member 2511 in the upward direction (Z direction) with respect to the conveyance direction. Due to the biasing of the first biasing member 253, the correction guide plate 251 returns to a predetermined position when the force in the processing direction in the removal process of the sheet P disappears.

[0088] The correction guide plate 251 is pivotally supported at a predetermined position by inserting a pin fixed to the housing of the folding processing unit 200 into a shaft hole 251 3 formed in the plate holding portion 2512. Then, the correction guide plate 251 rotates in the Z - Y plane with the shaft hole 2513 as the rotation center.

[0089] Therefore, when a downward force in the conveyance direction is applied to the elastic material portion 252 disposed at the downstream end in the conveyance direction of the correction guide plate 251, and when the elastic material portion 252 reaches the deformation limit, the downstream end in the conveyance direction rotates. As a result, it can retreat from the vicinity of the merging position.

[0090] When a further downward force in the conveyance direction is applied and the deformation of the elastic material portion 252 reaches the deformation limit where it no longer deforms, the plate member 2511 rotates downward in the conveyance direction due to the force applied to the elastic material portion 252. As a result, the path correction portion 250 is in a more retracted state from the vicinity of the merging position, and a processing space can be secured for pulling out the subsequent sheet P2 that has caused a jam.

[0091] Next, the operation of the path correction portion 250 when performing the removal process of the sheet P will be described with reference to FIG. 20. FIG. 20(a) illustrates a state where the sheet P has a conveyance failure and stops at the merging point of the circulation path and the carry-in path, that is, a jam state where the sheet P remains on the conveyance path. In the jam state, a process (removal process) of pulling out the stationary sheet P downward in the conveyance direction (-Z direction) is to be performed.

[0092] When the sheet P is pulled downward in the conveyance direction by the removal process, a downward external force is applied to the elastic material portion 252 at the downstream end of the correction guide plate 251 in the conveyance direction. This state is illustrated in FIG. 20(b). Due to the deformation of the elastic material portion 252, the downstream end of the correction guide plate 251 in the conveyance direction is in a state of retreating from the position where the sheet P had stayed.

[0093] When the sheet P is further pulled, as illustrated in FIG. 20(c), the external force becomes stronger than the tensile force of the first biasing member 253. As a result, the correction guide plate 251 rotates about the shaft hole 2513, and the downstream end in the conveyance direction rotates downward (-Z direction).

[0094] After that, as illustrated in FIG. 20(c), when the sheet P is removed, the correction guide plate 251 rotates by the tensile force of the first biasing member 253 and returns to the original position (FIG. 20(a)).

[0095] As described above, when removing the sheet P from the conveyance path, the pulling force for removing the sheet P causes the path correction unit 250 to retreat from the removal process space, enabling a situation where removal is easier. Also, if the jammed sheet P is removed, the path correction unit 250 returns to the initial position. Thereby, by securing the processing space during the removal process, the processability can be improved. Further, since it automatically returns to the original state when the process is completed, a decrease in the processability of conveyance defects can be suppressed.

[0096] In this embodiment, the first biasing member 253 is exemplified as the biasing force for restoring the correction guide plate 251 to the initial position. However, the member for restoring the correction guide plate 251 is not limited to this. For example, any member that deforms like a torsion coil spring and has the property of returning to its original state may be used.

[0097] [Second Embodiment of the Conveyance Path Correction Unit] Next, another embodiment of the conveyance path correction unit included in the post-processing apparatus according to the present invention will be described. FIG. 21 illustrates a path correction unit 250a as a conveyance path correction unit included in the folding processing unit 200 according to the present embodiment. The path correction unit 250a can be retracted to the upstream side in the conveyance direction. And after removing the sheet P in the jam state, it can return to the original position. The "original position" of the path correction unit 250a corresponds to a position where the conveyance direction of the preceding sheet P1 conveyed through the circulation path can be corrected to the first conveyance means R1.

[0098] When the subsequent sheet P2 has a conveyance failure at the confluence position with the circulation path, the jam sensor included in the various sensors 240 outputs a detection signal to the post-processing control unit 210. The post-processing control unit 210 notifies the user of the occurrence of a jam and moves the path correction unit 250a to the side of the zero-th conveyance means R0 as shown in FIG. 21(a). As a result, as shown in FIG. 21(a), the path correction unit 250a can be retracted from the space for removing the sheet P, and a processing space can be secured. And the sheet P can be pulled out in the processing direction S.

[0099] Note that the downstream end of the path correction unit 250a may also be made of an elastic material like the path correction unit 250. Thereby, even if a load is applied to the tip of the path correction unit 250a when removing the sheet P, the load can be released by bending, so that the removal of the sheet P can be facilitated.

[0100] Further, the guide plate 260 may be rotated, and the sensor may detect that an opening is provided, and the post-processing control unit 210 may execute the retraction operation of the path correction unit 250 triggered by the detection signal of the opening / closing sensor of the guide plate 260.

[0101] And when the opening / closing sensor detects that the guide plate 260 is closed as shown in FIG. 21(b), the post-processing control unit 210 may execute a return operation to return the path correction unit 250 to the original position.

[0102] Next, an example of the detailed structure of the path correction unit 250a will be described. FIG. 22 is a perspective view of the path correction unit 250a as viewed obliquely from the front in the X direction, which is the direction orthogonal to the Y direction as the conveyance direction of the sheet P. As illustrated in FIG. 22, the path correction unit 250a includes a correction guide plate 251a, an elastic material portion 252a, a second biasing member 253a, and a solenoid unit 254.

[0103] The correction guide plate 251a includes a plate member 2511a corresponding to a plate-like member that corrects the conveyance direction of the preceding sheet P1 conveyed along the circulation path to the direction of the first conveyance means R1 (Y direction), and a rib protruding in the X direction from the end portion of the plate member 2511a in the X direction, which is a movement holding portion 2512a that moves the correction guide plate 251a to a predetermined position.

[0104] The elastic material portion 252a is a plate-like member attached to the end portion on the downstream side in the conveyance direction of the plate member 2511a so as to extend in the conveyance direction, and is made of a material that elastically deforms.

[0105] One end of the second biasing member 253a is fixed to the movement holding portion 2512a that is the end portion of the plate member 2511a, and the other end is fixed to the housing of the folding processing unit 200 or the like. The second biasing member 253a biases the correction guide plate 251a to slide upstream in the conveyance direction. The second biasing member 253a is an elastic member that exerts a tensile force to slide the correction guide plate 251a from the merging position to the retracted position.

[0106] When the solenoid unit 254 is in the ON state, it biases the movement holding unit 2512a to pull it downstream in the conveyance direction. The operation of the solenoid unit 254 is performed by the post-processing control unit 210. When the opening / closing sensor of the guide plate 260 detects that the guide plate 260 has been opened, the post-processing control unit 210 turns off the solenoid unit 254. As a result, the correction guide plate 251a moves upstream in the conveyance direction by the biasing force of the second biasing member 253a. When the opening / closing sensor detects that the guide plate 260 has been closed, the solenoid unit 254 is turned on. The biasing force of the solenoid unit 254 is set to be stronger than the biasing force of the second biasing member 253a. Thereby, when the solenoid unit 254 is ON, the correction guide plate 251a is held at the merging position (see Fig. 21(a)).

[0107] [Second Embodiment of the Conveyance Path Correction Unit] Next, yet another embodiment of the conveyance path correction unit included in the post-processing apparatus according to the present invention will be described. Fig. 23 is a perspective view of the path correction unit 250b according to this embodiment as viewed obliquely from the front in the X direction, which is the direction orthogonal to the Y direction as the conveyance direction of the sheet P. As illustrated in Fig. 2 3 As exemplified, the path correction unit 250a includes a correction guide plate 251b and an elastic material part 252b, and the correction guide plate 251b is biased in a predetermined direction so as to rotate about the shaft hole 2513b. Note that the illustration of the biasing member is omitted.

[0108] The correction guide plate 251b has a plate member 2511b corresponding to a plate-like member that corrects the conveyance direction of the preceding sheet P1 conveyed through the circulation path to the direction (Y direction) of the first conveyance means R1, and a rib protruding from the upstream end of the plate member 2511b in the Y direction and serving as a rotation holding unit 2512b that rotates the correction guide plate 251b at a predetermined position.

[0109] The elastic material part 252b is a plate-like member attached to the downstream end of the plate member 2511b so as to extend in the conveyance direction and is made of a material that elastically deforms.

[0110] When the path correction unit 250b receives the subsequent sheet P2 and conveys the preceding sheet P1 that has been circulated and conveyed in the direction of the first conveying means R1, it is in the state illustrated in FIG. 23(a). In this case, the preceding sheet P1 is conveyed along the correction guide plate 251b without being affected by the deflection of the subsequent sheet P2.

[0111] When a conveyance failure occurs in the subsequent sheet P2, as illustrated in FIG. 23(b), the plate member 2511b is rotated about the shaft hole 2513b. Thereby, the correction guide plate 251b can be retracted from the merging position.

[0112] Note that the rotation of the correction guide plate 251b may use power such as a motor as a driving source, or a configuration that transmits the driving force from the driving source via a gear may be used.

[0113] As described above, according to the folding processing unit 200 according to the present embodiment, when performing post-processing including a process of stacking a plurality of sheets, the accuracy of aligning the leading ends of the stacked sheets and the accuracy of skew correction can be improved. And when a conveyance failure occurs in the configuration of stacking a plurality of sheets, the processability of the removal process of the defective sheet can be improved.

[0114] Note that the present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the technical gist thereof, and all technical matters included in the technical idea described in the claims are the subject of the present invention. The above embodiments show preferred examples, but those skilled in the art can realize various modified examples from the disclosed content. Such modified examples are also included in the technical scope described in the claims.

Explanation of Reference Numerals

[0115] 1: Printer 10: Printer control unit 11: CPU 12: ROM 13: RAM 14: Serial I / F 20: Image Creation Unit 21: Entrance 22: Exit 23: Diverging Claw 24: Discharge Tray 30: Image Reading Unit 40: Operation Display Unit 50: Post-Processing Control Unit 51: CPU 52: ROM 53: RAM 54: Serial I / F 60: Load 61: Driver 70: Sensor 100: Printer Main Body 200: Sheet Folding Device F1: First Folding Means F2: Second Folding Means J1: First Conveyor Diverging Means J2: Second Conveyor Diverging Means J3: Third Conveyor Diverging Means P: Sheet P1: Leading Sheet P2: Subsequent Sheet P3: Next Sheet PL: Final Sheet Q: Sheet Bundle R0: Zeroeth Conveyor Means R1: First Conveyor Means R2: Second Conveyor Means R3: Third Conveyor Means R4: Fourth Conveyor Means R5: Fifth Conveyor Means R6: Sixth Conveyor Means SN1: First Sheet Detection Sensor SN2: Second Sheet Detection Sensor SN3: Third Sheet P Detection Sensor SN4: Fourth Sheet Detection Sensor SN5: Fifth Sheet Detection Sensor SN6: Sixth Sheet P Detection Sensor SN7: Seventh Sheet Detection Sensor W1: First Conveyor Path W2: Second Conveyor Path W3: Third Conveyor Route W4: Fourth Conveyor Route W5: Fifth Conveyor Route W6: Sixth Conveyor Route W7: Seventh Conveyor Route

Prior Art Documents

Patent Documents

[0116]

Patent Document 1

Claims

1. A post-processing device comprising: a first conveying means for conveying downstream a sheet conveyed along a first conveying path; a second conveying means for conveying the sheet along a second conveying path; and a third conveying means for conveying the sheet along a third conveying path, the post-processing device circulating the sheet in the order of the first conveying path, the second conveying path, and the third conveying path to stack a plurality of sheets, wherein when merging from the third conveying path to the first conveying path, the post-processing device includes a conveying path correcting member for directing the conveying direction of the sheet conveyed from the circulating path toward the first conveying means, and the conveying path correcting member has a retracting mechanism capable of retracting from a merging position where the third conveying path merges into the first conveying path. The post-processing device is characterized by this.

2. The post-processing device according to claim 1, wherein the conveying path correcting member is disposed at a position where the conveying direction of a preceding sheet conveyed in a circulating manner and the conveying direction of a subsequent sheet being carried in interfere with each other in the first conveying path.

3. The conveying path correcting member is a plate member for correcting the conveying direction of the sheet in the first conveying path, a biasing member for biasing the surface direction of the plate member in a direction toward the first conveying means, and an elastic member installed at a downstream end portion of the plate member in the conveying direction and deformable in a direction orthogonal to the conveying direction. The post-processing device according to claim 1 or 2 is characterized by this.

4. When removing the sheet that has become defective in conveyance in the first conveying path, the plate member rotates in a direction orthogonal to the conveying direction to retract from the merging position and returns to the merging position after the removal of the sheet. The post-processing device according to claim 3 is characterized by this.

5. When removing the sheet that has become defective in conveyance in the first conveying path, the plate member pulls the sheet in the removal direction, causing the elastic member to deform. When the deformation limit of the elastic member is reached, the plate member rotates to retract from the merging position and returns to the merging position after the removal of the sheet. The post-processing device according to claim 3 is characterized by this.

6. The plate member is divided in a direction orthogonal to the conveying direction. When removing the sheet in the first conveying path, the plate member rotates in a direction orthogonal to the conveying direction to retract from the merging position, and after the removal of the sheet, each rotates to return to the merging position. The post-processing device according to claim 3 is characterized by this.

7. The post-processing device according to claim 3, wherein when removing the sheet in the first conveyance path, the plate member slides upstream in the conveyance direction to retract from the confluence position and returns to the confluence position after the sheet is removed.

8. An image forming apparatus including an image forming unit that forms an image on a sheet and a post-processing unit that performs post-processing on the sheet, wherein the post-processing unit is the post-processing device according to any one of claims 1 to 7.

9. An image forming system characterized by being configured by connecting an image forming apparatus including an image forming unit that forms an image on a sheet and the post-processing device according to any one of claims 1 to 7.

Images