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

Abstract

The present invention relates to a post-processing apparatus (200), an image forming apparatus (1), and an image forming system, provided with a circulation transport path, a zeroth transport member (R0), and a control section (50). The circulation transport path includes a first transport path (W1), a second transport path (W2), a third transport path (W3), a first transport member (R1), a second transport member (R2), and a third transport member (R3). The first and second transport members transport a preceding sheet (P1) along the first and second transport paths. The third transport member transports it from the third transport path to the first transport path. The zeroth transport member transports a succeeding sheet (P2) to the first transport member. The control section controls the third transport member to stop the preceding sheet, and then controls the zeroth transport member and the third transport member to overlap the preceding sheet with the succeeding sheet to form a sheet bundle (Q) having a shift amount (G) between leading ends of the preceding sheet and the succeeding sheet, and to make the leading ends of the preceding sheet and the succeeding sheet touch the first transport member.

Description

Technical Field

[0001] Embodiments of this disclosure relate to a post-processing device, an image forming apparatus having the post-processing device, and an image forming system having the post-processing device. Background Technology

[0002] Various types of post-processing devices are known to perform predetermined post-processing operations on sheet-like recording media on which images are formed. These post-processing devices are included as part of an image forming apparatus, or are connected to an image forming apparatus to form an image forming system.

[0003] When image forming processing, which involves forming an image on a sheet, and subsequent processing (post-processing) are performed as a series of operations, the long processing time of post-processing requires waiting time for the next image forming process, which may reduce productivity. To reduce the waiting time in the image forming apparatus caused by the long processing time of post-processing, a post-processing device including a pre-stacking mechanism temporarily stores the sheet that has been conveyed after image forming processing in the post-processing device.

[0004] Citation List

[0005] Patent documents

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2014-125312 Summary of the Invention

[0007] Technical issues

[0008] Japanese Patent Application Publication No. 2014-125312 discloses a post-processing device with a sheet circulation path, which enables a pre-stacking mechanism without increasing the size of the post-processing device. Additionally, Japanese Patent Application Publication No. 2014-125312 also discloses a technique for abutting and overlapping sheets with a conveyor roller arranged in the sheet circulation path.

[0009] However, because the preceding sheet conveyed in the sheet circulation path comes into contact with and bends against the conveyor roller, the technology disclosed in Japanese Patent Application Publication No. 2014-125312 cannot correct the skewness of the subsequent sheet, and the bending of the preceding sheet will interfere with the conveying of the subsequent sheet.

[0010] The purpose of this disclosure is to provide a post-processing apparatus that improves the accuracy of skew correction of overlapping sheets when performing post-processing including the processing of overlapping multi-sheet sheets.

[0011] Solution to the problem

[0012] The post-processing equipment includes a circulating conveyor path, a zero-level conveyor unit, and a control unit. The circulating conveyor path includes a first conveyor path, a second conveyor path, a third conveyor path, a first conveyor unit, a second conveyor unit, and a third conveyor unit. The first conveyor unit conveys the preceding sheet from the first conveyor path. The second conveyor unit conveys the preceding sheet along the second conveyor path. The third conveyor unit conveys the preceding sheet from the third conveyor path to the first conveyor path. The circulating conveyor path is configured to allow the preceding sheet to sequentially circulate through the first, second, and third conveyor paths via the first, second, and third conveyor units; the zero-level conveyor unit conveys the subsequent sheet towards the first conveyor unit in the first conveyor path. The control unit controls the operation of the zeroth conveying component, the first conveying component, the second conveying component, and the third conveying component. The control unit controls the third conveying component to stop the preceding sheet, and then controls the zeroth conveying component and the third conveying component to overlap the preceding sheet with the following sheet to form a sheet bundle with a displacement between the front end of the preceding sheet and the front end of the following sheet, and to make the front end of the preceding sheet and the front end of the following sheet touch the first conveying component.

[0013] Effects of the present invention

[0014] According to this disclosure, when the post-processing equipment performs post-processing including the processing of overlapping multi-sheet sheets, the post-processing equipment can improve the accuracy of skew correction of the overlapping sheets. Attached Figure Description

[0015] The accompanying drawings are intended to illustrate exemplary embodiments of the invention and should not be construed as limiting its scope. Unless explicitly stated otherwise, the drawings should not be considered to be drawn to scale. Furthermore, in all the drawings, the same or similar reference numerals denote the same or similar parts.

[0016] Figure 1 The image shown is a side view of an image forming apparatus that includes a post-processing device according to an embodiment of the present disclosure.

[0017] Figure 2 What is shown is Figure 1 A block diagram of the control structure of the image forming apparatus.

[0018] Figure 3 The diagram shows the internal structure of a sheet folding apparatus used as the post-processing equipment involved in this disclosure.

[0019] Figure 4 The diagram shown is an enlarged view of the internal structure of the sheet folding device according to this embodiment of the present disclosure.

[0020] Figure 5 The diagram shown is an enlarged view of the internal structure of the sheet folding apparatus according to this embodiment of the present disclosure, used to illustrate the post-processing.

[0021] Figure 6 The diagram shown is an enlarged view of the internal structure of the sheet folding device according to this embodiment of the present disclosure, for illustrative purposes. Figure 5 The next process shown.

[0022] Figure 7 The diagram shown is an enlarged view of the internal structure of the sheet folding device according to this embodiment of the present disclosure, for illustrative purposes. Figure 6 The next process shown.

[0023] Figure 8 The diagram shown is an enlarged view of the internal structure of the sheet folding device according to this embodiment of the present disclosure, for illustrative purposes. Figure 7 The next process shown.

[0024] Figure 9 The diagram shown is an enlarged view of the internal structure of the sheet folding device according to this embodiment of the present disclosure, for illustrative purposes. Figure 8 The next process shown.

[0025] Figure 10 The diagram shown is an enlarged view of the internal structure of the sheet folding device according to this embodiment of the present disclosure, for illustrative purposes. Figure 9 The next process shown.

[0026] Figure 11 The diagram shown is an enlarged view of the internal structure of the sheet folding device according to this embodiment of the present disclosure, for illustrative purposes. Figure 10 The next step in the folding action shown.

[0027] Figure 12 The diagram shown is an enlarged view of the internal structure of the sheet folding device according to this embodiment of the present disclosure, for illustrative purposes. Figure 11 The next folding action after the folding action shown.

[0028] Figure 13 The diagram shown is an enlarged view of the internal structure of the sheet folding device according to this embodiment of the present disclosure, for illustrative purposes. Figure 12 The next folding action after the folding action shown.

[0029] Figure 14 The diagram shown is an enlarged view of the internal structure of the sheet folding device according to this embodiment of the present disclosure, for illustrative purposes. Figure 13 The next folding action after the folding action shown.

[0030] Figure 15 The diagram shown is an enlarged view of the internal structure of the sheet folding equipment, used to illustrate the preceding sheet before the subsequent sheet.

[0031] Figure 16 The diagram shown is an enlarged view of the internal structure of the sheet folding apparatus according to this embodiment of the present disclosure, used to illustrate the subsequent sheet before the preceding sheet.

[0032] Figure 17 The diagram shown is an enlarged view of the internal structure of the sheet folding device according to this embodiment of the present disclosure, for illustrative purposes. Figure 16 The next process shown.

[0033] Figure 18 The diagram shown is an enlarged view of the internal structure of the sheet folding apparatus according to this embodiment of the present disclosure, used to illustrate the displacement when the preceding sheet and the subsequent sheet overlap each other.

[0034] Figure 19 The diagram shown is an enlarged view of the internal structure of the sheet folding device according to this embodiment of the present disclosure, used to illustrate the displacement amount when the next sheet is overlapped onto the subsequent sheet and the previous sheet.

[0035] Figure 20 The diagram shown is an enlarged view of the internal structure of the sheet folding device according to this embodiment of the present disclosure, used to illustrate the displacement amount when the next sheet is overlapped onto the subsequent sheet and the previous sheet.

[0036] Figure 21A , 21B The image shown is an enlarged view of the internal structure of a sheet folding device without a set displacement amount.

[0037] Figure 22 The diagram shows a flowchart of the controls involved in the first example executed by the sheet folding equipment.

[0038] Figure 23 The diagram shows a flowchart of the control involved in the second example performed by the sheet folding equipment.

[0039] Figure 24 The diagram shows a flowchart of the control involved in the third example performed by the sheet folding device.

[0040] Figure 25 The diagram shows a flowchart of the control involved in the fourth example performed by the sheet folding device.

[0041] Figure 26 The diagram shows a flowchart of the control involved in the fifth example performed by the sheet folding device. Detailed Implementation

[0042] The terms used herein are for illustrative purposes only and are not intended to limit the invention. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0043] In describing the embodiments shown in the accompanying drawings, specific terms have been used for clarity. However, the disclosure of this specification is not intended to be limited to the selected specific terms, and it should be understood that each specific element includes all technical equivalents that have similar functions, operate in a similar manner, and achieve similar results.

[0044] [Overview of Image Forming Apparatus]

[0045] First, the image forming apparatus according to the embodiments of this disclosure will be described. Figure 1 The diagram shown is an external view of the image forming apparatus 1, which serves as a printer. The image forming apparatus 1 includes an image forming device 100, which is the main body of the printer, and a sheet folding device 200, which can be connected to the image forming device 100 and serves as a post-processing device. Figure 1 As shown, the image forming apparatus 1 is an in-body discharge type device, and the sheet folding device 200 is incorporated into a part of the image forming apparatus 100. That is, the image forming apparatus 1 includes the sheet folding device 200 as a post-processing device to receive the recording medium on which the image is formed and to perform post-processing on the recording medium. The configuration of the sheet folding device 200 will be described later.

[0046] [Functional Structure of the Control Block]

[0047] Next, refer to Figure 2 This section describes the control blocks for controlling the image forming apparatus 100 and the sheet folding apparatus 200 involved in this embodiment. For example... Figure 2 As shown, the image forming apparatus 100 includes an image forming apparatus control unit 10 as a control block. The image forming apparatus control unit 10 includes a central processing unit (CPU) 11, a read-only memory (ROM) 12, a random access memory (RAM) 13, and a serial interface (serial I / F) 14.

[0048] The image forming apparatus control unit 10 is connected to the image forming unit 20, the image reading unit 30, and the operation display unit 40, which is typically a control panel. The image forming unit 20, the image reading unit 30, and the operation display unit 40 each include components that fully perform their functions. Each component of the image forming unit 20, the image reading unit 30, and the operation display unit 40 operates based on control signals issued by the image forming apparatus control unit 10.

[0049] The image forming unit 20 performs an image forming operation on a sheet P or a sheet-like recording medium, which serves as a recording medium, based on image data. The image reading unit 30 reads the image formed on the sheet P and acquires the image data of the image on the sheet P. The operation display unit 40 serves as an input unit for the operation conditions entered into the image forming unit 20 and the image reading unit 30, and as a display unit for displaying, for example, the operation result.

[0050] ROM12 stores control programs for controlling the image forming unit 20, the image reading unit 30, and the operation display unit 40. CPU11 reads the control program stored in ROM12 into RAM13. In addition, CPU11 stores data in RAM13 for use in control, and executes the control defined by the control program while using RAM13 as a working area.

[0051] like Figure 2 As shown, the sheet folding device 200 includes a post-processing control unit 50 as a control block. The post-processing control unit 50 includes a central processing unit (CPU) 51, a read-only memory (ROM) 52, a random access memory (RAM) 53, and a serial interface (serial I / F) 54.

[0052] The post-processing control unit 50 is connected to various components 60 and various sensors 70. The various components 60 are, for example, sheet transport rollers and pairs of sheet folding rollers, and include configurations for performing sheet folding operations on recording media. A drive motor drives the various components 60. For example, the drive motor drives and rotates various rollers and various roller pairs. The post-processing control unit 50 controls a driver 61 connected to the post-processing control unit 50 to drive the drive motors that drive the various components 60. The various components 60 perform operations such as transporting and folding the sheet P, which is the recording medium.

[0053] Various sensors 70 are multiple sheet detection sensors used to detect the position of sheet P in the sheet transport path, and are configured in the sheet transport path described later. The post-processing control unit 50 executes a pre-stored control program and determines the transport volume and position of the sheet P to be post-processed based on the detection signals output from the various sensors 70 to the post-processing control unit 50. Based on the drive quantities of various components 60, the post-processing control unit 50 can calculate the transport volume (transport distance) of sheet P after the leading edge of sheet P is detected by the sheet detection sensors and determine the position of sheet P.

[0054] The ROM 52 stores the control program for the post-processing control unit 50 to execute predetermined processes. The CPU 51 reads the control program stored in the ROM 52 into the RAM 53. Additionally, the CPU 51 stores data in the RAM 53 for use in controlling the sheet folding process, and executes the sheet folding process control defined by the control program while using the RAM 53 as a work area. As described above, the post-processing control unit 50 executes the control program stored in the ROM 52, controls the sheet detection sensor to detect the sheet P, and controls various components 60 to transport the sheet P.

[0055] The image forming apparatus control unit 10 of the image forming apparatus 100 and the post-processing control unit 50 of the sheet folding apparatus 200 are connected in a communicable manner via serial I / F 14 and serial I / F 54. This communication path is used to exchange control commands and data for transport control of the recording medium between the image forming apparatus control unit 10 and the post-processing control unit 50. Based on the control commands sent from the image forming apparatus 100, data about the recording medium, and data about the position of the recording medium obtained from various sensors 70, the sheet folding apparatus 200 determines whether to perform transport control and sheet folding operations on the recording medium, and switches the type of sheet folding operation.

[0056] The image forming apparatus 100 (i.e., the image forming apparatus control unit 10) sends information about the sheet P as data to the sheet folding apparatus 200 (i.e., the post-processing control unit 50). This data includes the type and thickness of the sheet P sent from the image forming apparatus 100 and received by the sheet folding apparatus 200. Additionally, the data includes the number of overlapping sheets P, the type of folding process performed on the sheet P, and whether an image exists at the folding position in the sheet P. Control commands from the image forming apparatus control unit 10 to the post-processing control unit 50 include commands indicating whether the transmitted sheet P corresponds to the last page (i.e., the last sheet) of the collective processing unit.

[0057] [Overview of the post-processing unit]

[0058] The internal structure of the sheet folding apparatus 200, which is the post-processing equipment according to this embodiment of the present disclosure, will be described below. Figure 3 The diagram shown is a schematic representation of the internal structure of a sheet folding device 200. The sheet folding device 200 includes multiple sheet conveying paths, multiple roller pairs, and multiple sheet detection sensors. Each of the multiple roller pairs serves as either a conveying component or a folding component.

[0059] The sheet folding equipment 200 has seven conveying paths that are largely distinct from each other. For example... Figure 3As shown, the sheet folding equipment 200 includes a first conveying path W1, a second conveying path W2, a third conveying path W3, a fourth conveying path W4, a fifth conveying path W5, a sixth conveying path W6, and a seventh conveying path W7.

[0060] Furthermore, the sheet folding equipment 200 includes multiple roller pairs arranged along a first conveying path W1, a second conveying path W2, a third conveying path W3, a fourth conveying path W4, a fifth conveying path W5, and a sixth conveying path W6, respectively. Each of the multiple roller pairs is respectively arranged in the conveying path to convey the sheet P and serves as a zero conveying member R0, a first conveying member R1, a second conveying member R2, a third conveying member R3, a fourth conveying member R4, a fifth conveying member R5, and a sixth conveying member R6. The post-processing control unit 50 executes a control program to control these conveying members and start and stop the conveying of the sheet P.

[0061] The sheet folding device 200 has multiple switching guides. For example, the multiple switching guides guide sheet P from a first conveying path W1 to a second conveying path W2, and sheet P, guided and conveyed to the second conveying path W2, is conveyed back to the first conveying path W1 via a third conveying path W3. That is, the multiple switching guides guide sheet P to a circulating conveying path in which sheet P circulates. Alternatively, the multiple switching guides guide sheet P to a fourth conveying path W4 downstream of the first conveying path W1, i.e., a circulating conveying path that does not guide sheet P from the first conveying path W1 to the downstream of the second conveying path W2. Alternatively, the multiple switching guides guide sheet P from the first conveying path W1 to the second conveying path W2, and further guide sheet P to a fifth conveying path W5 downstream of the second conveying path W2. To perform the above-described switching of conveying paths, the sheet folding device 200 includes multiple switching guides.

[0062] like Figures 4 to 10 As shown, the multiple switching guides include a first switching guide J1, a second switching guide J2, and a third switching guide J3. These multiple switching guides are included in various components 60 controlled by the post-processing control unit 50. The post-processing control unit 50 controls the operation of the multiple switching guides to determine the conveying path of the sheet P. Additionally, the sheet folding device 200 has a first folding component F1 and a second folding component F2 for folding the sheet P in the cyclic conveying path.

[0063] The sheet folding apparatus 200 includes a zero-level transport member R0 near the inlet 21 where the sheet P is received from the image forming apparatus 100, serving as an entry roller pair. After the post-processing control unit 50 receives a signal indicating that the sheet P will be discharged from the image forming apparatus 100, the post-processing control unit 50 controls the drive motor of the zero-level transport member R0 to begin rotating the zero-level transport member R0. Subsequently, the leading edge of the sheet P reaches the clamping portion of the roller pair of the zero-level transport member R0, and the zero-level transport member R0 transports the sheet P downstream of the transport path.

[0064] As described below, before the sheet folding device 200 discharges the sheet P received from the image forming device 100 to the outlet 22 downstream of all transport paths, the sheet folding device 200 receives the next sheet P and performs sheet overlap processing and folding processing, whereby the next sheet P is transported and overlapped onto the previous sheet P. In the following description, for illustrative purposes, the sheet P received from the image forming device 100, i.e., the previous sheet, is referred to as "previous sheet P1". The next sheet P, i.e., the sheet P following the previous sheet P1, is referred to as "subsequent sheet P2". After the previous sheet P1 is received by the sheet folding device 200, the subsequent sheet P2 is received by the sheet folding device 200. Furthermore, the sheet P received by the sheet folding device 200 after the subsequent sheet P2 and subjected to sheet overlap processing is referred to as "next sheet P3". Additionally, the multi-sheet sheets P stacked together are referred to as "sheet bundle Q".

[0065] In addition, the sheet folding device 200 can overlap and fold more than three sheets P. The number of sheets P stacked or folded in the sheet folding device 200 is not limited to three sheets.

[0066] The first conveying component R1 has a pair of rollers facing each other across the first conveying path W1, forming a gap between the rollers. The first folding component F1 includes a pair of rollers facing each other and disposed between the first sheet conveying path W1 and the second sheet conveying path W2, forming a gap between the rollers. The path guided by the gaps in the first conveying component R1 and the first folding component F1 will guide the sheet P1 from the first conveying path W1 to the second conveying path W2.

[0067] The preceding sheet P1, guided to the second transport path W2, is conveyed to the third transport path W3 via the second transport member R2. Subsequently, the third transport member R3 temporarily halts the conveying of the preceding sheet P1 in the third transport path W3. When the sheet folding device 200 receives the subsequent sheet P2 from the image forming device 100, the third transport member R3 resumes the conveying of the preceding sheet P1, which was temporarily halted in the third transport path W3. As a result, the preceding sheet P1 returns to its upstream position in the first transport path W1, where it meets the subsequent sheet P2. This constitutes a cyclic transport path.

[0068] In the aforementioned cyclic conveying path, the preceding sheet P1 and the subsequent sheet P2 overlap to form a sheet bundle Q. The folding process performed on the sheet bundle Q is described below.

[0069] The post-processing control unit 50 controls the first folding component F1 to fold the sheet bundle Q. The sheet bundle Q, folded by the first folding component F1, is conveyed from the second conveying path W2 to the fifth conveying path W5. The fourth conveying component R4, the fifth conveying component R5, and the first folding component F1 are driven by the same drive motor. The drive motor can rotate in both forward and reverse directions. By changing the direction of rotation, the drive motor conveys the sheet bundle Q, in which the preceding sheet P1 and the subsequent sheet P2 are overlapped, and performs the sheet folding process.

[0070] A branch claw 23 is disposed downstream of and adjacent to the sixth conveying component R6. The branch claw 23 switches the guiding posture to guide the sheet P (or sheet bundle Q) toward the sixth conveying path W6 or the seventh conveying path W7. The branch claw 23 can switch the guiding posture, for example, by driving a solenoid. Alternatively, a drive mechanism including a motor, gears, cams, etc., can be used instead of a solenoid.

[0071] Sheet P, having passed through the fourth conveyor path W4 or the fifth conveyor path W5, is discharged and stacked onto the output tray 24 of the sheet folding device 200. When the image forming system is configured to include a post-processing device arranged downstream of the sheet folding device 200, the seventh conveyor path W7 is the path that transfers sheet P to the post-processing device. The post-processing device performs post-processing such as alignment or binding on the folded or unclamped sheet P.

[0072] The first sheet detection sensor SN1 is located downstream of and adjacent to the zeroth conveying component R0 on the first conveying path W1. The second sheet detection sensor SN2 is located upstream of and adjacent to the first conveying component R1. The third sheet detection sensor SN3 is located downstream of and adjacent to the second conveying component R2 on the third conveying path W3. The fourth sheet detection sensor SN4 is located downstream of and adjacent to the third conveying component R3 on the third conveying path W3. The fifth sheet detection sensor SN5 is located downstream of and adjacent to the fourth conveying component R4 on the fourth conveying path W4. The sixth sheet detection sensor SN6 is located downstream of and adjacent to the fifth conveying component R5 on the fifth conveying path W5. The seventh sheet detection sensor SN7 is located downstream of and adjacent to the sixth conveying component R6 on the sixth conveying path W6.

[0073] Figure 3 The sheet folding device 200 shown is capable of performing inward and outward triple folds on overlapping sheets P. (Refer to...) Figures 4-10 This describes the action of overlapping two sheets P in the sheet circulation path to form a sheet bundle Q.

[0074] Figure 4 The image shows a sheet folding device 200 in its initial state before the sheet P is fed from the image forming apparatus 100. When the leading edge of the sheet P1 fed from the image forming apparatus 100 reaches the exit of the image forming apparatus 100, the post-processing control unit 50 in the sheet folding device 200 begins to rotate the zeroth conveying device R0. (As shown...) Figure 5 As shown, the zeroth conveying unit R0 receives the preceding sheet P1 and conveys the preceding sheet P1 to the first conveying path W1. Additionally, the post-processing control unit 50... Figure 4 The first switching guide J1 is moved as shown to transport the first sheet P1 to the second transport path W2 instead of the fourth transport path W4.

[0075] The first sheet detection sensor SN1 detects the leading edge of the preceding sheet P1 conveyed by the zeroth conveying member R0 and notifies the post-processing control unit 50 of the detection signal. When the first sheet detection sensor detects the leading edge of the preceding sheet P1, the first conveying member R1 stops. Figure 5 As shown, the post-processing control unit 50 maintains the first conveying member R1 in a stopped state until the amount of conveying the prior sheet P1 required to correct the bending of the prior sheet P1 at the front end of the prior sheet P1 (i.e., the first protrusion amount) reaches a predetermined value after the detection signal is notified.

[0076] like Figure 6As shown, when the first protrusion reaches a predetermined value, that is, when the correction of the skew at the front end of the first sheet P1 is completed, the post-processing control unit 50 starts the rotation of the first conveying member R1.

[0077] When the front end of the sheet P1 enters the gap of the first conveying member R1, the post-processing control unit 50 causes the first folding member F1, the second conveying member R2 and the third conveying member R3 to rotate.

[0078] like Figure 7 As shown, the rotation of the first conveying member R1 and the first folding member F1 conveys the first sheet P1 to the second conveying path W2, and the first sheet P1 is conveyed along the downward slope of the second conveying path W2. The second conveying member R2 conveys the first sheet P1, which is being conveyed along the downward slope of the second conveying path W2, to the third conveying path W3. Subsequently, the third conveying member R3 conveys the first sheet P1 to the fourth sheet detection sensor SN4. The fourth sheet detection sensor SN4 detects the leading edge of the first sheet P1 and notifies the post-processing control unit 50 of the detection signal. After receiving the detection signal from the fourth sheet detection sensor SN4, the post-processing control unit 50 calculates the timing of the first sheet P1 reaching a position corresponding to a second protrusion amount Δ2 corresponding to the position of the first sheet P1 leaving the fourth sheet detection sensor SN4.

[0079] When the post-processing control unit 50 determines that the front end of the pre-sheet P1 has reached the position corresponding to the second protrusion Δ2, such as Figure 8 As shown, the post-processing control unit 50 stops the rotation of the first folding member F1, the second conveying member R2 and the third conveying member R3, thereby stopping the conveying of the prior sheet P1.

[0080] However, even when the post-processing control unit 50 stops the conveying of the first sheet P1, the post-processing control unit 50 continues to rotate the first conveying member R1 to receive the subsequent sheet P2 conveyed from the image forming apparatus 100.

[0081] Subsequently, after the first sheet detection sensor SN1 detects the leading edge of the subsequent sheet P2 and notifies the post-processing control unit 50 of the detection signal, the post-processing control unit 50 calculates as follows: Figure 9 The timing of stopping the conveying of the subsequent sheet P2 is shown. At the stopping time, the leading edge of the subsequent sheet P2 reaches a position corresponding to the third protrusion Δ3 away from the first sheet detection sensor SN1. When the leading edge of the subsequent sheet P2 reaches the position corresponding to the third protrusion Δ3, the post-processing control unit 50 restarts the rotation of the second conveying member R2 and the third conveying member R3. As a result, as shown... Figure 9As shown, the feeding of the previously stopped sheet P1 is restarted. Thus, the leading edge of the subsequent sheet P2, which contacts the first feeding member R1, is slightly earlier than the leading edge of the previously contacted sheet P1, and the skewness of the subsequent sheet P2 is corrected.

[0082] The post-processing control unit 50 calculates the third protrusion amount Δ3 based on the speed of the sheet moved by the zeroth conveying member R0, the speed of the sheet conveyed by the third conveying member R3, and the positions of the zeroth conveying member R0, the third conveying member R3, the first sheet detection sensor SN1, the second sheet detection sensor SN2, and the fourth sheet detection sensor SN4, i.e., the distance between these components. When the leading edges of the preceding sheet P1 and the following sheet P2 meet each other before the preceding sheet P1 and the following sheet P2 contact the first conveying member R1, the third protrusion amount Δ3 defines the displacement between the leading edges of the preceding sheet P1 and the following sheet P2.

[0083] After that, as Figure 9 As shown, the front ends of the first sheet P1 and the front ends of the subsequent sheet P2 meet each other in front of the second sheet detection sensor SN2 to form a sheet bundle Q, and the sheet bundle Q passes through the roller gap of the first conveying member R1 and is conveyed downstream from the roller gap of the first conveying member R1.

[0084] Subsequently, the post-processing control unit 50 determines whether the number of sheets to be folded, as notified by the image forming apparatus 100, matches the number of sheets received by the sheet folding device 200. When the number of sheets to be folded matches the number of sheets received by the sheet folding device 200, the post-processing control unit 50 performs the following folding process. When the number of sheets to be folded does not match the number of sheets received by the sheet folding device 200, the post-processing control unit 50 performs the following process again. Figures 7 to 9 The process shown involves the next sheet P3 (i.e., the sheet P transported after the subsequent sheet P2) from the image forming apparatus 100 encountering the sheet bundle Q to overlap the next sheet P3 onto the sheet bundle Q. Furthermore, the post-processing control unit 50 can determine, for example, whether the sheet P has been transported immediately ahead of the roller gap of the second transport member R2 based on the number of drive steps of the drive motor that drives and rotates the first transport member R1. Therefore, it is preferable to use a stepper motor as the drive motor to drive and rotate each transport member.

[0085] [Overview of folding process]

[0086] The folding operation of the sheet folding device 200 according to this embodiment will now be described. Figures 11-14 This is an enlarged view illustrating the internal structure of a sheet folding device for performing an outward triple folding operation on a sheet bundle Q formed on the upstream side of the first conveying member R1.

[0087] Reference Figure 10 The sheet bundle Q is formed when the first sheet P1 meets the subsequent sheet P2, and the zeroth conveying component R0 and the first conveying component R1 convey the sheet bundle Q. When the leading end of the sheet bundle Q enters the roller gap of the first conveying component R1, the sheet bundle Q is conveyed to the fourth conveying component R4.

[0088] When the first conveying member R1 conveys the sheet bundle Q to the immediate front of the roller gap of the fourth conveying member R4, the post-processing control unit 50 drives the motor to, in addition to causing the first conveying member R1 to... Figure 11 The circular arrow in the middle rotates in the direction of the arc, and also causes the fourth conveying component R4 to move towards... Figure 11 The circular arrow indicates rotation. After the fifth sheet detection sensor SN5 detects the leading edge of the sheet bundle Q and notifies the post-processing control unit 50 of the detection signal, the post-processing control unit 50 drives the fourth conveying member R4 to convey the leading edge of the sheet bundle Q by a fourth protrusion amount Δ4. When the leading edge of the sheet bundle Q has been conveyed by the fourth protrusion amount Δ4, the post-processing control unit 50 temporarily stops the fourth conveying member R4.

[0089] Next, as Figure 12 As shown, the post-processing control unit 50 causes the fourth conveying member R4 and the first folding member F1 to rotate in opposite directions, so that the first conveying member R1 moves towards... Figure 11 While rotating in the direction shown, it moves towards the direction shown. Figure 11 The sheet bundle Q is conveyed in the opposite direction shown. The reverse rotation of the fourth conveying component R4 conveys the sheet bundle Q in the opposite direction to the conveying direction.

[0090] like Figure 13 As shown, the first conveying member R1 rotates and conveys the sheet bundle Q in the conveying direction, while the fourth conveying member R4 rotates in the opposite direction to convey the sheet bundle Q in the opposite direction. As a result, the sheet bundle Q forms a bend before the roller gap of the first folding member F1. The bend enters the roller gap, and the first folding member F1 performs a first fold, thereby forming a first fold line.

[0091] The first folding component F1 conveys the sheet bundle Q, which has undergone the first fold, to the second conveying path W2, and conveys the sheet bundle Q along the downward slope of the second conveying path W2. After the third sheet detection sensor SN3 detects the front end of the sheet bundle Q, the second conveying component R2 conveys the front end of the sheet bundle Q by a fifth protrusion Δ5. When the second conveying component R2 conveys the front end of the sheet bundle Q by the fifth protrusion Δ5, the post-processing control unit 50 temporarily stops the second conveying component R2.

[0092] Next, in Figure 13 While rotating the fourth conveying component R4 and the first folding component F1 in the conveying direction shown, the post-processing control unit 50 moves towards the direction shown. Figure 13 The direction shown is opposite to the direction in which the second conveying member R2 rotates. The reverse rotation of the second conveying member R2 conveys the sheet bundle Q in the direction opposite to that of the second conveying member R2. Additionally, the post-processing control unit 50... Figure 13 The fourth conveying component R4 and the first folding component F1 are rotated in the direction shown to convey the sheet bundle Q. The result is as follows: Figure 14 As shown, the sheet bundle Q is bent before the roller gap of the second folding member F2, which also serves as the fifth conveying member R5. The bent portion enters the roller gap, and the second folding member F12 performs a second fold, thereby forming a second fold line.

[0093] The sheet bundle Q, after the second fold, is conveyed to the output tray 24 via the fifth conveying path W5. The fourth protrusion Δ4 and the fifth protrusion Δ5 are determined based on the total length of the sheet P and the folding method set for the sheet P (or sheet bundle Q). The post-processing control unit 50 determines whether the sheet P or sheet bundle Q has moved by the fourth protrusion Δ4 based on the rotation amount of the fourth conveying member R4 (i.e., the number of drive steps of the drive motor), and determines whether the sheet P or sheet bundle Q has moved by the fifth protrusion Δ5 based on the rotation amount of the second conveying member R2 (i.e., the number of drive steps of the drive motor).

[0094] When the sheet folding device 200 performs an outward triple folding operation on sheet P, as a first folding operation, sheet P is folded outward from the front end of sheet P in the sheet conveying direction at a position corresponding to two-thirds (2 / 3) of the total length of sheet P. Then, as a second folding operation, sheet P is folded inward at a position corresponding to two-thirds (2 / 3) of the total length of sheet P. When the sheet folding device 200 performs an inward triple folding operation on sheet P, as a first folding operation, sheet P is folded outward from the front end of sheet P in the sheet conveying direction at a position corresponding to one-third (1 / 3) of the total length of sheet P, and as a second folding operation, it is folded inward at a position corresponding to two-thirds (2 / 3) of the total length of sheet P.

[0095] [Example of the first action]

[0096] Next, refer to Figures 15 to 18 A first operational example of the sheet folding apparatus 200 according to this embodiment will be described. (Refer to...) Figure 15 and 16 The movement of the preceding sheet P1 and the following sheet P2 is described as follows: the front end of the preceding sheet P1, which is stationary on the third conveying path W3, precedes the front end of the following sheet P2 and is offset from the front end of the following sheet P2 in the sheet conveying direction. The preceding sheet P1 and the following sheet P2 are conveyed overlappingly.

[0097] like Figure 15As shown, before the subsequent sheet P2 contacts the first conveying component R1, the leading edge of the preceding sheet P1, preceding the leading edge of the subsequent sheet P2, collides with the rollers of the first conveying component R1. When the leading edge of the preceding sheet P1 collides with the rollers of the first conveying component R1, the preceding sheet P1... Figure 16 The bending is shown. Since the subsequent sheet P2 received from the image forming apparatus 100 is located above the preceding sheet P1 in the first transport path W1, the aforementioned bending of the preceding sheet P1 causes the subsequent sheet P2 to bend. As a result, as Figure 16 As shown, the first sheet P1 pushes aside the subsequent sheet P2, and the front end of the subsequent sheet P2 does not reach the roller of the first conveying component R1 and does not touch the roller.

[0098] As a result, the skew correction of subsequent sheet P2 is insufficient, and the leading edges of the sheets in sheet bundle Q are misaligned when subsequent sheet P2 overlaps with the preceding sheet P1. The same problem occurs when the leading edge of subsequent sheet P2 aligns with the leading edge of the preceding sheet P1, which is stationary on the third conveying path W3. However, these problems are caused by variations in the first sheet detection sensor SN1, variations in the fourth sheet detection sensor SN4, the curling of sheet P, and mechanical variations in the sensor positions. When the preceding sheet P1 and subsequent sheet P2 overlap, these factors cause the preceding sheet P1 to precede the subsequent sheet P2, resulting in the aforementioned problems.

[0099] Reference Figure 17 and 18 To illustrate the movement of the preceding sheet P1 and the following sheet P2, the leading edge of the following sheet P2 precedes the leading edge of the preceding sheet P1 and is offset by a length G from the leading edge of the preceding sheet P1 in the sheet conveying direction. The preceding sheet P1 and the following sheet P2 are conveyed overlappingly. Figure 17 When conveying the preceding sheet P1 and the following sheet P2 as shown, the leading edge of the following sheet P2 touches the roller of the first conveying component R1 before the leading edge of the preceding sheet P1 contacts the leading edge of the first conveying component R1.

[0100] When the leading edge of the subsequent sheet P2 collides with the roller of the first conveying member R1, the subsequent sheet P2 bends. However, since the preceding sheet P1 is below the subsequent sheet P2 in the first conveying path W1, the bending of the subsequent sheet P2 does not affect the conveying of the preceding sheet P1. Therefore, the leading edges of both the preceding sheet P1 and the subsequent sheet P2 can reach the first conveying member R1. As a result, the above configuration can prevent bending caused by… Figure 16 The inadequacy of the skew correction caused by the bending of the prior sheet P1 and the misalignment between the front ends of the sheets to be overlapped are shown.

[0101] Consider several methods to determine the restart timing of conveying the preceding sheet P1, which is stopped on the third conveyor path W3. The following example illustrates a method when the preceding sheet P1 and the following sheet P2 are conveyed at the same speed. In the following description, the point where the leading edge of the preceding sheet P1 meets the following sheet P2 is as follows: Figure 17 The point shown is called the confluence point H. The distance from the confluence point H to the front end of the preceding sheet P1, which protrudes by a second protrusion amount Δ2 from the fourth sheet detection sensor SN4, is set to be no less than the sum of length G and the distance from the confluence point H to the front end of the subsequent sheet P2, which protrudes by a third protrusion amount Δ3. When the front end of the subsequent sheet P2 reaches the position corresponding to the third protrusion amount Δ3, the third conveying member R3 restarts its rotation. As a result, the front end of the subsequent sheet P2 precedes the front end of the preceding sheet P1 and is offset by length G from the front end of the preceding sheet P1 in the sheet conveying direction, allowing the preceding sheet P1 and the subsequent sheet P2 to be conveyed overlappingly. If factors such as the layout of components in the post-processing equipment prevent the distance from the confluence point H to the front end of the preceding sheet P1, which protrudes by a second protrusion amount Δ2 from the fourth sheet detection sensor SN4, from being equal to or greater than the sum of the length G and the distance from the confluence point H to the front end of the subsequent sheet P2, which protrudes by a third protrusion amount Δ3 from the first sheet detection sensor SN1, then, except for the third protrusion amount Δ3 from the first sheet detection sensor SN1, when the front end of the subsequent sheet P2 has been conveyed for a length G, the third conveying component R3 restarts its rotation. As a result, the front end of the subsequent sheet P2 precedes the front end of the preceding sheet P1 and is offset by a length G from the front end of the preceding sheet P1 in the sheet conveying direction, allowing the preceding sheet P1 and the subsequent sheet P2 to be conveyed overlappingly.

[0102] [Example of the second action]

[0103] Next, refer to Figures 19 to 2 1. A second operational example of the sheet folding apparatus 200 according to this embodiment will be described. (Refer to...) Figures 19 to 2 1. The following describes the displacement (i.e., length G) between the front end of the first sheet P1 and the front end of the subsequent sheet P2 when the first sheet P1 and the subsequent sheet P2 overlap.

[0104] exist Figure 19 In this context, length G is set as displacement Amm, which is the amount of displacement between the leading edge of the preceding sheet P1 and the leading edge of the following sheet P2 when the preceding sheet P1 and the following sheet P2 overlap. The unit of length G is millimeters. Hereinafter, the units for length G and the protrusion amount are millimeters.

[0105] like Figure 19As shown, a first sheet P1 is overlapped on a subsequent sheet P2, and the leading edge of the subsequent sheet P2 is displaced from the leading edge of the first sheet P1 by an amount Amm to form a sheet bundle Q. The sheet bundle Q collides with the first conveying member R1, which is in a stopped state. In this case, the post-processing control unit 50 controls the conveying of the sheet bundle Q, such that the first protrusion Δ1 of the sheet bundle Q colliding with the first conveying member R1 becomes "amm".

[0106] After the sheet bundle Q collides with the first conveying member R1, the post-processing control unit 50 drives and rotates the first conveying member R1 to convey the sheet bundle Q, including the preceding sheet P1 and the following sheet P2, to the first folding member F1. Subsequently, the post-processing control unit 50 drives and rotates the first conveying member R1, the second conveying member R2, and the third conveying member R3 to convey the sheet bundle Q to the fourth sheet detection sensor SN4. Then, the post-processing control unit 50 conveys the sheet bundle Q (the preceding sheet P1 and the following sheet P2) until the leading edge of the preceding sheet P1 or the following sheet P2 reaches a position corresponding to a second protrusion Δ2, which is a predetermined protrusion amount after the fourth sheet detection sensor SN4 detects the leading edge of the preceding sheet P1 or the following sheet P2. When the leading edge of the preceding sheet P1 or the following sheet P2 reaches the position corresponding to the second protrusion Δ2, the post-processing control unit 50 stops conveying the sheet bundle Q.

[0107] While the third conveying component R3 holds and stops the preceding sheet P1 and the following sheet P2, the next sheet P3... Figure 20 As shown, after the image forming apparatus 100 delivers the next sheet P2, the post-processing control unit 50 monitors the time elapsed since the first sheet detection sensor SN1 detected the leading edge of the next sheet P3.

[0108] When the elapsed time becomes the scheduled time, such as Figure 20 As shown, the post-processing control unit 50 drives the second conveying component R2 and the third conveying component R3 to overlap the preceding sheet P1 and the subsequent sheet P2 onto the next sheet P3. When the sheet bundle Q, including the preceding sheet P1 and the subsequent sheet P2, overlaps onto the next sheet P3, the length G between the front end of the next sheet P3 and the front end of the sheet bundle Q is set to a displacement amount B mm. The displacement amount B is shorter than the displacement amount A, and the relationship A>B holds true.

[0109] Reference Figure 21A , 21B The reasons for the post-processing control unit 50 performing the above-mentioned controls are explained below. Figure 21AAs shown, assume that the first sheet P1 and the subsequent sheet P2 contact the first conveying component R1 to correct their respective skewness and are neatly arranged at the front ends of the first sheet P1 and the subsequent sheet P2, respectively. They are then conveyed along a circular conveying path to the position where the fourth sheet detection sensor SN4 detects either the first sheet P1 or the subsequent sheet P2. At this time, the first sheet P1 travels along the inner path of the circular conveying path, and the subsequent sheet P2 travels along the outer path. That is, the movement of the first sheet P1 is shorter than the movement of the subsequent sheet P2, similar to the difference in the tracks between the front and rear inner wheels when a vehicle turns.

[0110] The result is, as Figure 21B As shown, even if the front end of the first sheet P1 and the front end of the subsequent sheet P2 are aligned in the roller gap of the first conveying component R1, when the fourth sheet detection sensor SN4 detects the front end of the first sheet P1 or the subsequent sheet P2, the first sheet P1 is ahead of the subsequent sheet P2. Figure 21B The leading amount Cmm shown is not limited to the amount caused by the aforementioned differences, but also by the variation in the position of the leading edges of the preceding sheet P1 and the subsequent sheet P2 entering the roller gap of the first to third conveying components. This variation is increased by the curling of the preceding sheet P1 and the subsequent sheet P2.

[0111] When the fourth sheet detection sensor SN4 detects the leading edge of the preceding sheet P1 or the leading edge of the following sheet P2, in order to align the leading edge of the preceding sheet P1 with the leading edge of the following sheet P2, the post-processing control unit 50 controls the zero-level conveying member R0 and the third-level conveying member R3 so that the leading edge of the following sheet P2 leads the leading edge of the preceding sheet P1 by a lead amount Cmm. When the preceding sheet P1 and the following sheet P2 are conveyed downstream from the first conveying member R1, the lead amount Cmm corresponds to the displacement between the leading edges of the preceding sheet P1 and the following sheet P2.

[0112] Based on the above, when the preceding sheet P1 encounters the following sheet P2, the displacement Amm between the front end of the preceding sheet P1 and the front end of the following sheet P2 is calculated as the sum of "amm" (the first protrusion Δ1) and the preceding amount Cmm, with "+αmm" as a margin. When the following sheet P3 encounters the sheet bundle Q, the displacement Bmm between the front end of the following sheet P3 and the front end of the sheet bundle Q (including the preceding sheet P1 and the following sheet P2) is calculated as the sum of "amm" (the first protrusion Δ1) of the following sheet P3 and "+αmm" as a margin.

[0113] In the above embodiment, three sheets P overlap. When four or more sheets P overlap, the displacement of the last overlapping sheet P (i.e., the last sheet PL) is different from the displacement of the sheets that are not the last overlapping sheets.

[0114] [The first example of the control process for a sheet folding machine 200]

[0115] Next, an example of the control flow of the sheet folding equipment 200 will be described. The control program executed by the post-processing control unit 50 includes the following control flow.

[0116] Figure 22 The diagram shows a flowchart of a first example of the control flow of the sheet folding device 200. First, in step S2101, the post-processing control unit 50 obtains information about the sheet P from the image forming device control unit 10. Then, the preceding sheet P1 is conveyed in the sheet circulation path, and the fourth sheet detection sensor SN4 detects the leading edge of the preceding sheet P1. In step S2102, the post-processing control unit 50 stops conveying the preceding sheet P1 after the fourth sheet detection sensor SN4 detects the leading edge of the preceding sheet P1, which has reached the position corresponding to the second protrusion amount Δ2.

[0117] In step S2103, the sheet folding device 200 receives the subsequent sheet P2. In step S2104, the post-processing control unit 50 determines the type of the preceding sheet P1.

[0118] When the post-processing control unit 50 determines that the preceding sheet P1 is a normal sheet, the post-processing control unit 50 sets the third protrusion amount Δ3 to a displacement amount Amm. The third protrusion amount Δ3 is the amount of protrusion of the leading edge of the subsequent sheet P2 from the position of the first sheet detection sensor SN1 after the first sheet detection sensor SN1 detects the leading edge of the subsequent sheet P2. Then, in step S2105, after the third protrusion amount Δ3 relative to the subsequent sheet P2 reaches the displacement amount Amm, the post-processing control unit 50 restarts the rotation of the third conveying member R3 and causes the preceding sheet P1 to encounter the subsequent sheet P2 in the first conveying path W1.

[0119] When the post-processing control unit 50 determines that the preceding sheet P1 is a thick sheet, the post-processing control unit 50 sets the third protrusion amount Δ3 to a displacement amount A'mm that is larger than the displacement amount Amm. Then, in step S2106, after the third protrusion amount Δ3 relative to the subsequent sheet P2 reaches the displacement amount A'mm, the post-processing control unit 50 restarts the rotation of the third conveying member R3 and causes the preceding sheet P1 to encounter the subsequent sheet P2 in the first conveying path W1.

[0120] When the preceding sheet is thick, the subsequent sheet P2 overlaps the preceding sheet P1 until it is conveyed to the position of the fourth sheet detection sensor SN4. The thickness of the preceding sheet P1 increases the conveying distance of the subsequent sheet P2, and the conveying distance of the subsequent sheet P2 overlapping the thicker sheet is longer than that of the subsequent sheet P2 overlapping the ordinary sheet. In the first example, the third protrusion Δ3 is set as a displacement A'mm to pre-increase the displacement between the front end of the preceding sheet P1 and the front end of the subsequent sheet P2. When the preceding sheet P1 and the subsequent sheet P2 reach the position detected by the fourth sheet detection sensor SN4, the above control reduces the distance between the front end of the preceding sheet P1 and the front end of the subsequent sheet P2.

[0121] In step S2107, in the first conveying path W1, the preceding sheet P1 encounters the subsequent sheet P2, and the preceding sheet P1 and the subsequent sheet P2 collide with the stopped first conveying component R1 to correct the skew.

[0122] In step S2108, during the folding process, the post-processing control unit 50 performs the folding process as described above and discharges the sheet bundle Q.

[0123] [Second example of the control process for sheet folding equipment 200]

[0124] Figure 23 The diagram shows a second flowchart of the control flow of the sheet folding device 200. First, in step S2201, the post-processing control unit 50 obtains information about the sheet P from the image forming device control unit 10. Then, the preceding sheet P1 is conveyed in the sheet circulation path, and the fourth sheet detection sensor SN4 detects the leading edge of the preceding sheet P1. In step S2202, the post-processing control unit 50 stops conveying the preceding sheet P1 after the fourth sheet detection sensor SN4 detects the leading edge of the preceding sheet P1, which has reached the position corresponding to the second protrusion amount Δ2.

[0125] In step S2203, the sheet folding device 200 receives the subsequent sheet P2. In step S2204, the post-processing control unit 50 determines the type of the preceding sheet P1.

[0126] When the post-processing control unit 50 determines that the preceding sheet P1 is a normal sheet, the post-processing control unit 50 sets the third protrusion amount Δ3 to a displacement amount Amm. Then, in step S2205, after the third protrusion amount Δ3 relative to the subsequent sheet P2 reaches the displacement amount Amm, the post-processing control unit 50 restarts the rotation of the third conveying member R3 and causes the preceding sheet P1 to encounter the subsequent sheet P2 in the first conveying path W1.

[0127] In step S2207, in the first conveying path W1, the preceding sheet P1 encounters the following sheet P2, and the preceding sheet P1 and the following sheet P2 collide with the stopped first conveying member R1 to correct the skew. In step S2207, the post-processing control unit 50 controls the conveying of the sheet bundle Q, such that the first protrusion Δ1 of the sheet bundle Q colliding with the first conveying member R1 becomes "amm".

[0128] When the post-processing control unit 50 determines that the preceding sheet P1 is a thick sheet, the post-processing control unit 50 sets the third protrusion amount Δ3 to a displacement amount A'mm that is larger than the displacement amount Amm. Then, in step S2206, after the third protrusion amount Δ3 relative to the subsequent sheet P2 reaches the displacement amount A'mm, the post-processing control unit 50 restarts the rotation of the third conveying member R3 and causes the preceding sheet P1 to encounter the subsequent sheet P2 in the first conveying path W1.

[0129] In step S2208, in the first conveying path W1, the preceding sheet P1 encounters the following sheet P2, and the preceding sheet P1 and the following sheet P2 collide with the stopped first conveying member R1 to correct the skew. In step S2208, the post-processing control unit 50 controls the conveying of the sheet bundle Q, such that the first protrusion Δ1 of the sheet bundle Q colliding with the first conveying member R1 becomes "a'mm", which is larger than "amm".

[0130] After step S2207 or step S2208, when performing the folding process, the post-processing control unit 50 performs the folding process as described above and discharges the sheet bundle Q in step S2209.

[0131] When the next sheet P3 encounters a sheet bundle Q including the preceding sheet P1 and the following sheet P2 to form a new sheet bundle and collide with the first conveying member R1 in the stop, the post-processing control unit 50 sets the first protrusion amount Δ1 to a length longer than "a'mm".

[0132] That is, when the post-processing control unit 50 changes the displacement between the front end of the preceding sheet P1 and the front end of the subsequent sheet P2 to "A'" based on information about the sheet type, the post-processing control unit 50 increases the first protrusion amount Δ1 of the next sheet P3 overlapping the subsequent sheet P2 and the preceding sheet P1. During the correction of the skewness of the next sheet P3, the above control can correct the skewness of the preceding sheet P1 and the subsequent sheet P2. As a result, the above control can improve the alignment accuracy of the front ends.

[0133] [The third example of the control process for sheet folding equipment 200]

[0134] Figure 24The diagram shows the third flowchart of the control flow of the sheet folding device 200. First, in step S2301, the post-processing control unit 50 obtains information about the printing surface of the sheet from the image forming device control unit 10 as information about the sheet P. Then, the preceding sheet P1 is conveyed in the sheet circulation path, and the fourth sheet detection sensor SN4 detects the leading edge of the preceding sheet P1. In step S2302, after the fourth sheet detection sensor SN4 detects the leading edge of the preceding sheet P1, the post-processing control unit 50 stops conveying the preceding sheet P1, which has reached the position corresponding to the second protrusion amount Δ2.

[0135] In step S2303, the sheet folding device 200 receives the subsequent sheet P2. In step S2304, the post-processing control unit 50 determines whether the printing surface of the preceding sheet P1 is the upper surface or the lower surface.

[0136] When the post-processing control unit 50 determines that the printing surface of the preceding sheet P1 is on the upper surface of the preceding sheet P1, the post-processing control unit 50 sets the third protrusion amount Δ3 to a displacement amount Emm. Then, in step S2305, after the third protrusion amount Δ3 relative to the subsequent sheet P2 reaches the displacement amount Emm, the post-processing control unit 50 restarts the rotation of the third conveying member R3 and causes the preceding sheet P1 to encounter the subsequent sheet P2 in the first conveying path W1.

[0137] When the post-processing control unit 50 determines that the printing surface of the preceding sheet P1 is on the lower surface of the preceding sheet P1, the post-processing control unit 50 sets the third protrusion amount Δ3 to a displacement amount Fmm that is larger than the displacement amount Emm. Then, in step S2306, after the third protrusion amount Δ3 relative to the subsequent sheet P2 reaches the displacement amount Fmm, the post-processing control unit 50 restarts the rotation of the third conveying member R3 and causes the preceding sheet P1 to encounter the subsequent sheet P2 in the first conveying path W1.

[0138] In step S2307, in the first conveying path W1, the preceding sheet P1 encounters the following sheet P2, and the preceding sheet P1 and the following sheet P2 collide with the stopped first conveying member R1 to correct the skew. Additionally, in step S2307, during the folding process, the post-processing control unit 50 performs the folding process as described above and discharges the sheet bundle Q.

[0139] In this example, the post-processing control unit 50 changes the displacement between the leading edge of the preceding sheet P1 and the leading edge of the subsequent sheet P2 based on the state of the printing surfaces of the overlapping sheets. The post-processing control unit 50 receives information about the printing surface of the sheet P from the image forming apparatus control unit 10, the printing surface of the sheet P being the surface on which the image is formed.

[0140] When the printing surface is on the upper surface of the first sheet P1, the post-processing control unit 50 controls the zeroth transport member R0 and the third transport member R3, so that the displacement between the front end of the first sheet P1 and the front end of the subsequent sheet P2 becomes Emm. When the printing surface is on the lower surface of the first sheet P1, the post-processing control unit 50 controls the zeroth transport member R0 and the third transport member R3, so that the displacement between the front end of the first sheet P1 and the front end of the subsequent sheet P2 becomes Fmm. In both cases, the first sheet P1 precedes the subsequent sheet P2, thus forming a relationship of Fmm > Emm.

[0141] When the printing surface is on the upper surface of the first sheet P1, if image forming processing is performed using an electrophotographic method, the toner adhering to the printing surface will affect and reduce friction between the sheets P. As a result, when folding is performed on the sheet bundle Q, the subsequent sheet P2 slides, and the leading edges of the sheets overlapping in the sheet bundle Q shift. Anticipating this, by pre-displacing the sheets P, it is possible to reduce the shift after folding.

[0142] [Fourth example of the control process for sheet folding equipment 200]

[0143] Figure 25 The diagram shows the fourth flow chart of the control process of the sheet folding device 200. First, in step S2401, the post-processing control unit 50 obtains information about the position of the printed image on the sheet P from the image forming device control unit 10 as information about the sheet P. Then, the preceding sheet P1 is conveyed in the sheet circulation path, and the fourth sheet detection sensor SN4 detects the leading edge of the preceding sheet P1. In step S2402, after the fourth sheet detection sensor SN4 detects the leading edge of the preceding sheet P1, the post-processing control unit 50 stops conveying the preceding sheet P1 after it reaches the position corresponding to the second protrusion amount Δ2.

[0144] In step S2403, the sheet folding device 200 receives the subsequent sheet P2. In step S2404, the post-processing control unit 50 determines whether the printed image is in the folded position.

[0145] When the post-processing control unit 50 determines that the printed image is in the folded position (Yes in step S2404), the post-processing control unit 50 sets the third protrusion amount Δ3 to the displacement amount Gmm. Then, in step S2405, after the third protrusion amount Δ3 relative to the subsequent sheet P2 reaches the displacement amount Gmm, the post-processing control unit 50 restarts the rotation of the third conveying member R3 and causes the preceding sheet P1 to encounter the subsequent sheet P2 in the first conveying path W1.

[0146] When the post-processing control unit 50 determines that the printed image is not in the folded position (No in step S2404), the post-processing control unit 50 sets the third protrusion Δ3 to a displacement Hmm greater than Gmm. Then, in step S2406, after the third protrusion Δ3 relative to the subsequent sheet P2 reaches the displacement Hmm, the post-processing control unit 50 restarts the rotation of the third conveying member R3 and causes the preceding sheet P1 to encounter the subsequent sheet P2 in the first conveying path W1.

[0147] In step S2407, in the first conveying path W1, the preceding sheet P1 encounters the following sheet P2, and the preceding sheet P1 and the following sheet P2 collide with the stopped first conveying member R1 to correct the misalignment. Additionally, in step S2407, during the folding process, the post-processing control unit 50 performs the folding process as described above and discharges the sheet bundle Q.

[0148] In this example, the post-processing control unit 50 receives information about the position of the printed image from the image forming apparatus 100. When the printed image is in the folded position of the sheet P, the post-processing control unit 50 changes the displacement between the leading edge of the first sheet P1 and the leading edge of the subsequent sheet P2 to "Gmm". When the printed image is not in the folded position of the sheet P, the post-processing control unit 50 changes the displacement between the leading edge of the first sheet P1 and the leading edge of the subsequent sheet P2 to "Hmm". Regardless of the displacement amount, the first sheet P1 is pre-displaced.

[0149] When the printed image is in the folded position, if the image forming process is performed using an electrophotographic method, the toner adhering to the printed surface will affect and reduce friction between the sheets P. As a result, when folding is performed on the sheet bundle Q, the subsequent sheet P2 slides, and the leading edges of the sheets overlapping in the sheet bundle Q shift. Anticipating this, by pre-displacing the sheets P, it is possible to reduce the shifting after folding.

[0150] [The fifth example of the control process for sheet folding equipment 200]

[0151] Figure 26 The diagram shows the fifth step of the control flow of the sheet folding device 200. First, in step S2501, the post-processing control unit 50 obtains folding type information from the image forming device control unit 10 as information for the sheet P. Then, the preceding sheet P1 is conveyed in the sheet circulation path, and the fourth sheet detection sensor SN4 detects the leading edge of the preceding sheet P1. In step S2502, after the fourth sheet detection sensor SN4 detects the leading edge of the preceding sheet P1, the post-processing control unit 50 stops conveying the preceding sheet P1, which has reached the position corresponding to the second protrusion amount Δ2.

[0152] In step S2503, the sheet folding device 200 receives the subsequent sheet P2. In step S2504, the post-processing control unit 50 determines the type of folding.

[0153] When the post-processing control unit 50 determines that the folding type is an outward triple fold, the post-processing control unit 50 sets the third protrusion amount Δ3 to a displacement amount Kmm. Then, in step S2505, after the third protrusion amount Δ3 relative to the subsequent sheet P2 reaches the displacement amount Kmm, the post-processing control unit 50 restarts the rotation of the third conveying member R3 and makes the preceding sheet P1 meet the subsequent sheet P2 in the first conveying path W1.

[0154] In step S2507, in the first conveying path W1, the preceding sheet P1 encounters the subsequent sheet P2, and the preceding sheet P1 and the subsequent sheet P2 collide with the stopped first conveying component R1 to correct the skew.

[0155] When the post-processing control unit 50 determines that the folding type is not an outward triple fold, the post-processing control unit 50 sets the third protrusion Δ3 to a displacement amount Lmm greater than Kmm. Then, in step S2506, after the third protrusion Δ3 relative to the subsequent sheet P2 reaches the displacement amount Lmm, the post-processing control unit 50 restarts the rotation of the third conveying member R3 and makes the preceding sheet P1 meet the subsequent sheet P2 in the first conveying path W1.

[0156] In step S2508, in the first conveying path W1, the preceding sheet P1 encounters the following sheet P2, and both the preceding sheet P1 and the following sheet P2 collide with the stopped first conveying member R1 to correct the skew. Then, in step S2508, the sheet folding device performs a specified inward three-fold and discharges the paper bundle Q.

[0157] In this example, the post-processing control unit 50 receives information about the fold type from the image forming apparatus 100. When the fold type is an outward tri-fold, the post-processing control unit 50 changes the displacement between the front end of the first sheet P1 and the front end of the subsequent sheet P2 to "Kmm". When the fold type is an inward tri-fold, the post-processing control unit 50 changes the displacement between the front end of the first sheet P1 and the front end of the subsequent sheet P2 to "Lmm". Regardless of the displacement amount, the first sheet P1 is pre-displaced.

[0158] Setting the displacement between the front end of the preceding sheet P1 and the front end of the subsequent sheet P2 in the inner three-fold process to be greater than that in the outer three-fold process can improve the alignment accuracy of the front ends after the folding process is completed.

[0159] The sheet folding device 200 described in this embodiment can improve the accuracy of skew correction of overlapping sheets and the accuracy of alignment of the front ends of overlapping sheets when performing post-processing that includes processing of overlapping multi-sheet sheets in a post-processing device.

[0160] This disclosure is not limited to the specific embodiments described above, and many additional modifications and variations can be made within the technical scope of this disclosure based on its teachings. Therefore, it should be understood that those skilled in the art can practice the disclosure of this specification in ways other than those specifically described herein. Such implementations and variations thereof are included within the scope and spirit of the embodiments of this disclosure, and are also included within the scope of the embodiments recited in the claims and their equivalents.

[0161] The above embodiments are illustrative and do not limit the invention. Therefore, many additional modifications and variations can be made in light of the above teachings. For example, within the scope of the invention, elements and / or features of different illustrative embodiments can be combined with and / or substituted for each other. Any of the above operations can be performed in various other ways, for example, in an order different from that described above. Each of the functions of the embodiments can be implemented by one or more processing circuits or circuits. The processing circuit includes a programmable processor, which includes circuitry. The processing circuit also includes devices such as application-specific integrated circuits (ASICs), digital signal processors (DSPs), field-programmable gate arrays (FPGAs), and conventional circuit components configured to perform the listed functions.

[0162] This patent application is based on and claims priority to Japanese Patent Application No. 2020-141859, filed with the Japan Patent Office on August 25, 2020, the entire disclosure of which is incorporated herein by reference.

[0163] List of reference numerals

[0164] 1 Image forming apparatus

[0165] 10 Image Forming Equipment Control Unit

[0166] 11. Central Processing Unit (CPU)

[0167] 12 Read-Only Memory (ROM)

[0168] 13. Random Access Memory (RAM)

[0169] 14 Serial Interfaces (I / F)

[0170] 20 image forming units

[0171] 21 entrances

[0172] 22 Exports

[0173] 23-branch claw

[0174] 24 output trays

[0175] 30 image reading units

[0176] 40 operation display units

[0177] Post-processing control department

[0178] 51 Central Processing Unit (CPU)

[0179] 52 Read-Only Memory (ROM)

[0180] 53 Random Access Memory (RAM)

[0181] 54 Serial Interfaces (I / F)

[0182] 60 components

[0183] 61 drives

[0184] 70 sensors

[0185] 100 Image Forming Equipment

[0186] 200 sheet folding equipment

[0187] F1 First Fold

[0188] F2 Second Fold

[0189] J1 First Switching Guide

[0190] J2 Second Switching Guide

[0191] J3 Third Switching Bootstrap

[0192] P-sheet

[0193] P1 First-hand sheet

[0194] P2 Subsequent Films

[0195] P3 Next sheet

[0196] PL final sheet

[0197] Q sheet bundle

[0198] R0 Zeroth Conveying Component

[0199] R1 First Conveying Component

[0200] R2 Second Conveying Component

[0201] R3 Third Conveying Component

[0202] R4 Fourth Conveying Component

[0203] R5 Fifth Conveying Component

[0204] R6 Sixth Conveying Component

[0205] SN1 First Sheet Inspection Sensor

[0206] SN2 Second Sheet Detection Sensor

[0207] SN3 Third Sheet Detection Sensor

[0208] SN4 Fourth Sheet Detection Sensor

[0209] SN5 Fifth Sheet Inspection Sensor

[0210] SN6 sixth sheet detection sensor

[0211] SN7 Seventh Sheet Detection Sensor

[0212] W1 First Conveying Path

[0213] W2 Second Conveying Path

[0214] W3 Third Conveying Path

[0215] W4 Fourth Conveying Path

[0216] W5 Fifth Conveying Path

[0217] W6 Sixth Conveying Path

[0218] W7 Seventh Conveying Path

Claims

1. A post-processing device, characterized in that... include: A circular transport path has the following characteristics: First transport path; Second transport path; Third delivery path; A first conveying component is configured to convey a prior sheet from the first conveying path; The second conveying component is configured to convey the prior sheet along the second conveying path, and A third conveying component is configured to convey the prior sheet from the third conveying path to the first conveying path. The cyclic conveying path is configured such that the prior sheet sequentially circulates through the first conveying component, the second conveying component, and the third conveying component; A zeroth conveying component is configured to convey the prior sheet and subsequent sheet toward the first conveying component in the first conveying path; and The control unit is configured to control the operation of the zeroth conveying component, the first conveying component, the second conveying component, and the third conveying component. The control unit is configured as follows: The first conveying member that stops the collision of the prior sheet, after the prior sheet collides with the first conveying member, drives and rotates the first conveying member to continue conveying the prior sheet; When multiple sheets are stacked on top of each other on the circulating conveyor path, the third conveyor component is controlled to stop the preceding sheet. Then, the zeroth conveyor component and the third conveyor component are controlled to overlap the preceding sheet with the subsequent sheet, forming a bundle of preceding sheets with a displacement between the leading edges of the preceding and subsequent sheets, such that the leading edge of the subsequent sheet leads the leading edge of the preceding sheet. The bundle of preceding sheets is then caused to collide with the stopped first conveyor component. After the bundle of preceding sheets collides with the first conveyor component, the first conveyor component is driven and rotated to continue conveying the bundle of preceding sheets. The zeroth conveying component and the third conveying component are controlled to repeatedly overlap the preceding sheet bundle with the subsequent sheet, forming a sheet bundle with a displacement between the front end of the preceding sheet bundle and the front end of the subsequent sheet in such a way that the front end of the subsequent sheet leads the front end of the preceding sheet bundle, thereby forming a sheet bundle comprising multiple sheets, and the displacement between the front end of the last sheet finally overlapped on the preceding sheet bundle and the front end of the subsequent sheet is less than the displacement between the front end of the preceding sheet and the front end of the subsequent sheet.

2. The post-processing equipment according to claim 1, characterized in that: The control unit is configured to change the displacement amount according to the type of the prior sheet.

3. The post-processing equipment according to claim 1 or 2, characterized in that: The control unit is configured to change the displacement amount based on the state of the printed surface of the prior sheet.

4. The post-processing equipment according to claim 1 or 2, characterized in that: The control unit is configured to change the displacement amount based on the relationship between the folding position of the sheet bundle to be folded and the image forming position of the image formed on the sheet of the sheet bundle.

5. The post-processing equipment according to claim 1 or 2, characterized in that: The control unit is configured to change the displacement amount according to the folding type of the bundle of sheets to be folded.

6. An image forming apparatus, characterized in that... include: An image forming apparatus configured to form an image on a sheet, and The post-processing apparatus according to any one of claims 1 to 5.

7. An image forming system, characterized in that... include: An image forming apparatus configured to form an image on a sheet, and The post-processing apparatus according to any one of claims 1 to 5.

Images