Sheet processing apparatus and image forming system

Abstract

To provide a sheet processing device capable of performing accurate drilling and an image forming system equipped with the same.SOLUTION: This sheet processing device comprises: a conveyance unit that conveys a sheet in a sheet conveying direction; a drilling unit that drills a hole in the sheet conveyed by the conveyance unit; a movement unit that moves the drilling unit in a direction intersecting the sheet conveying direction; a detection unit that is disposed upstream of the drilling unit in the sheet conveying direction and that changes an output value on the basis of the position of the end of the conveyed sheet in the intersecting direction; a cleaning unit that cleans the detection unit; and an interlocking unit that moves the cleaning unit in linkage with the movement of the drilling unit in the intersecting direction. The cleaning unit is moved by the interlocking unit to clean the detection unit.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a sheet processing apparatus for processing sheets and an image forming system including the same. [Background technology]

[0002] 2. Description of the Related Art As an option for an image forming apparatus, such as an electrophotographic multifunction peripheral, a sheet processing apparatus is used that performs processes such as binding and sorting on sheets on which images have been formed by the image forming apparatus main body.

[0003] Conventionally, a sheet post-processing device has been proposed that detects the side edge of a sheet using a lateral registration detection sensor and moves a punching means in the width direction to match the size of the sheet (see Patent Document 1).Also proposed is a sheet processing device that detects the side edge of a sheet using a line sensor and moves a punch unit in the width direction according to the detection result of the line sensor (see Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-279170 [Patent Document 2] Patent Publication No. 2021-62440 Summary of the Invention [Problem to be solved by the invention]

[0005] The lateral registration detection sensor described in Patent Document 1 and the line sensor described in Patent Document 2 are both optical sensors that receive light using a light receiving unit. If paper dust discharged from a conveyed sheet accumulates on the optical sensor, the optical sensor may not be able to correctly detect the side edge of the sheet. This can reduce the positioning accuracy of the perforation means or punch unit, which moves widthwise in response to the detection result of the optical sensor, and can reduce the positional accuracy of holes punched in the sheet.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a sheet processing apparatus capable of punching holes with high accuracy and an image forming system including the same. [Means for solving the problem]

[0007] The present invention is a sheet processing device comprising: a conveying unit that conveys a sheet in a sheet conveying direction; a punching unit that punches holes in the sheet conveyed by the conveying unit; a moving unit that moves the punching unit in a cross direction that intersects the sheet conveying direction; a detection unit that is arranged upstream of the punching unit in the sheet conveying direction and changes an output value based on the position of the end of the conveyed sheet in the cross direction; a cleaning unit that cleans the detection unit; and an interlocking unit that moves the cleaning unit in conjunction with the movement of the punching unit in the cross direction, wherein the cleaning unit cleans the detection unit by being moved by the interlocking unit. [Effects of the Invention]

[0008] According to the present invention, it is possible to punch holes in a sheet with high precision. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is an overall schematic diagram showing an image forming system according to a first embodiment. [Figure 2] 1A is a schematic diagram showing a punch positioned at a punch start position, FIG. 1B is a schematic diagram showing a punch positioned at a punch completion position, and FIG. 1C is a schematic diagram showing a punch positioned at a separation position. [Figure 3] FIG. 2 is a block diagram showing functional blocks of a post-processing device. [Figure 4] FIG. 2 is a block diagram showing the hardware configuration of a post-processing device. [Figure 5] (a) is a plan view showing the state where the leading edge of the sheet has reached the inlet sensor, (b) is a plan view showing the state where the target position of the hole has reached the line sensor, (c) is a plan view showing the state where the sheet has been moved in the width direction, and (d) is a plan view showing the state where the sheet has been perforated. [Figure 6](a) is a plan view showing the state when the target position of the second hole has reached the line sensor, (b) is a plan view showing the state when the sheet has been moved in the width direction, (c) is a plan view showing the state when the sheet has been perforated, and (d) is a plan view showing the state after the rear end of the sheet has passed the line sensor. [Figure 7] 1A is a plan view showing the cleaning unit, FIG. 1B is a plan view showing the punch base abutting against the arm, and FIG. 1C is a plan view showing the nonwoven fabric having moved to a cleaning completion position. [Figure 8] 10 is a flowchart showing cleaning control. [Figure 9] (a) is a plan view showing a cleaning unit according to a second embodiment, (b) is a plan view showing the punch base abutting against the arm, and (c) is a plan view showing the nonwoven fabric moving to the cleaning completion position. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings.

[0011] First Embodiment [Overall configuration] The image forming system 1S according to the first embodiment is made up of an image forming device 1, an image reading device 2, a document feeding device 3, and a post-processing device 4. The image forming system 1S forms an image on a sheet, which is a recording material, and processes the sheet using the post-processing device 4 as needed before outputting it. Below, we will briefly explain the operation of each device, and then provide a detailed explanation of the post-processing device 4.

[0012] The document feeder 3 transports documents placed on a document tray 18 to image reading units 16 and 19. The image reading units 16 and 19 are each an image sensor that reads image information from the document surface, and both sides of the document are read in one document transport. The document from which the image information has been read is discharged to a document discharge unit 20. In addition, the image reading unit 2 can read image information from a stationary document set on the document glass (including a document that cannot be used with the document feeder 3, such as a booklet document) by reciprocating the image reading unit 16 using a drive unit 17.

[0013] Image forming apparatus 1 is an electrophotographic device equipped with a direct transfer type image forming unit 1B. Image forming unit 1B includes a cartridge 8 equipped with a photosensitive drum 9 and a laser scanner unit 15 disposed above cartridge 8. During image formation, the surface of rotating photosensitive drum 9 is charged, and laser scanner unit 15 exposes photosensitive drum 9 based on image information, thereby writing an electrostatic latent image onto the drum surface. The electrostatic latent image carried on photosensitive drum 9 is developed into a toner image by charged toner particles, and the toner image is transported to a transfer unit where photosensitive drum 9 faces transfer roller 10. A control unit of image forming apparatus 1 controls image forming unit 1B to perform image formation based on image information read by image reading units 16 and 19 or image information received from an external computer via a network.

[0014] The image forming apparatus 1 is equipped with a plurality of feeding devices 6 that feed sheets as recording materials one by one at predetermined intervals. The sheets fed from the feeding devices 6 are corrected for skew by registration rollers 7 and then transported to a transfer section, where a toner image carried on a photosensitive drum 9 is transferred onto the sheets. A fixing unit 11 is disposed downstream of the transfer section in the sheet transport direction. The fixing unit 11 has a pair of rotating bodies that sandwich and transport the sheets, and a heating element such as a halogen lamp for heating the toner image, and fixes the image by applying heat and pressure to the toner image on the sheet.

[0015] When an image-formed sheet is to be discharged outside the image forming apparatus 1, the sheet that has passed through the fixing unit 11 is conveyed to the post-processing device 4 via the horizontal conveying section 14. In the case of a sheet on which image formation on the first side has been completed in double-sided printing, the sheet that has passed through the fixing unit 11 is handed over to the reversing rollers 12, is conveyed in a switchback manner by the reversing rollers 12, and is conveyed again to the registration rollers 7 via the re-conveying section 13. The sheet then passes through the transfer section and the fixing unit 11 again, where an image is formed on the second side, and is then conveyed to the post-processing device 4 via the horizontal conveying section 14.

[0016] The image forming unit 1B is an example of an image forming means for forming an image on a sheet, and may be an electrophotographic unit of an intermediate transfer type in which a toner image formed on a photosensitive member is transferred to a sheet via an intermediate transfer member. Alternatively, a printing unit of an inkjet type or an offset printing type may be used as the image forming means.

[0017] [Post-processing device] The post-processing device 4 as a sheet processing device has a punching processing section 4A that punches holes in sheets and a binding processing section 4B that binds sheets, and performs punching and binding processes on sheets received from the image forming device 1 and discharges the sheets as a sheet bundle. The post-processing device 4 can also simply discharge the sheets received from the image forming device 1 without performing punching and binding processes on them.

[0018] The post-processing device 4 is provided with an receiving path 81, an inner discharge path 82, a first discharge path 83, and a second discharge path 84 as transport paths for transporting sheets, and an upper discharge tray 25 and a lower discharge tray 37 as destinations for discharging sheets. The receiving path 81 as the first transport path is a transport path that receives and transports sheets from the image forming device 1, and the inner discharge path 82 as the second transport path is a transport path that extends below the receiving path 81 and guides the sheets toward the binding processing unit 4B. The first discharge path 83 is a transport path that discharges sheets to the upper discharge tray 25, and the second discharge path 84 as the third transport path is a transport path that extends along the sheet discharge direction and guides the sheets to the lower discharge tray 37.

[0019] A sheet discharged from the horizontal conveying unit 14 of the image forming apparatus 1 is received by the entrance rollers 21 serving as a conveying unit arranged in the receiving path 81, and is conveyed through the receiving path 81 toward the pre-reversal rollers 22. The entrance sensor 27 detects the sheet at a detection position between the entrance rollers 21 and the pre-reversal rollers 22. The pre-reversal rollers 22 convey the sheet received from the entrance rollers 21 toward the first discharge path 83.

[0020] At a predetermined timing after the entrance sensor 27 detects the passage of the trailing edge of the sheet, the pre-reversal rollers 22 accelerate the sheet conveying speed to a speed faster than the conveying speed in the horizontal conveying section 14. Alternatively, the sheet conveying speed by the entrance rollers 21 may be set to be faster than that of the horizontal conveying section 14, and the conveying speed may be accelerated by the entrance rollers 21 upstream of the pre-reversal rollers 22. In this case, it is preferable to install a one-way clutch between the conveying rollers of the horizontal conveying section 14 and the motor that drives them, so that the conveying rollers will rotate freely even if the sheet is pulled by the entrance rollers 21.

[0021] When the sheet is discharged to the upper discharge tray 25, the reversing rollers 24 discharge the sheet received from the pre-reversing rollers 22 to the upper discharge tray 25. In this case, the reversing rollers 24 decelerate to a predetermined discharge speed at a predetermined timing after the rear end of the sheet has passed the pre-reversing rollers 22.

[0022] When the sheet is discharged to the lower discharge tray 37, the reversing rollers 24 as a reversing unit perform switchback transport to reverse the sheet received from the pre-reversing rollers 22, and transport the sheet to the internal discharge path 82. A check valve 23 is disposed at a branching point where the receiving path 81 and the internal discharge path 82 branch off from the first discharge path 83, upstream of the reversing rollers 24 in the sheet discharge direction by the reversing rollers 24. The check valve 23 has a function of preventing the sheet switched back by the reversing rollers 24 from flowing back into the receiving path 81. The pre-reversing rollers 22 reverse their rotation direction when the trailing edge of the sheet passes through the check valve 23.

[0023] The inner discharge roller 26, intermediate conveyance roller 28, and kick-out roller 29, which are a pair of rotating bodies arranged in the inner discharge path 82, sequentially transfer the sheets received from the reversing roller 24 and convey them toward the binding processing unit 4B. When buffering sheets, the inner discharge roller 26 temporarily stops while holding the preceding sheet. The inner discharge roller 26 then reverses in synchronization with the succeeding sheet heading toward the reversing roller 24, buffering the preceding sheet by overlapping it on the succeeding sheet in the first discharge path. By repeatedly switching back the inner discharge roller 26, the sheet buffering makes it possible to buffer multiple sheets regardless of their lengths.

[0024] The intermediate pre-stacking sensor 38 detects a sheet between the intermediate conveying roller 28 and the kick-out roller 29. The entrance sensor 27 and the intermediate pre-stacking sensor 38 can be optical sensors that use light to detect the presence or absence of a sheet at the detection position, and can detect the passage of the leading and trailing ends of a sheet and the presence or absence of a jammed sheet.

[0025] The binding processing section 4B has an intermediate lower guide 31 as a stacking section on which sheets are stacked, a vertical alignment roller 32, a vertical alignment reference plate 33, a bundle discharge guide 34, a guide drive section 35, and a stapler and a horizontal alignment mechanism (not shown). Sheets sent from the internal discharge path 82 are stacked on the intermediate lower guide 31 and abutted against the vertical alignment reference plate 33 by the vertical alignment roller 32. This aligns the sheets in the sheet conveyance direction.

[0026] Next, the sheets are aligned in the width direction perpendicular to the sheet conveyance direction by a lateral alignment mechanism (not shown) and stapled by a stapler (not shown). The sheet stack stapled by the stapler is pushed out by a stack discharge guide 34 driven by a guide drive unit 35 and delivered to stack discharge rollers 36 via a second discharge path 84. The sheet stack is then discharged outside the machine by the stack discharge rollers 36 as a discharge unit and stacked on a lower discharge tray 37.

[0027] Both the upper discharge tray 25 and the lower discharge tray 37 are movable up and down relative to the housing of the post-processing device 4. The post-processing device 4 is equipped with sheet surface detection sensors that detect the position of the upper surface of sheets on the upper discharge tray 25 and the lower discharge tray 37, and when either sensor detects a sheet, the corresponding tray is lowered. Furthermore, when the sheet surface detection sensor detects that a sheet has been removed from the upper discharge tray 25 or the lower discharge tray 37, that tray is raised. Therefore, the upper discharge tray 25 and the lower discharge tray 37 are controlled to move up and down so as to keep the upper surfaces of the stacked sheets constant.

[0028] [Perforation processing section] Next, the punching processing unit 4A will be described in detail. As shown in FIGS. 2(a) to 2(c), the punching processing unit 4A has inlet rollers 21 that transport the sheet SH in the sheet transport direction D1, an inlet sensor 27, a side edge detection unit 305, a punch unit 62, and a shift unit (not shown). The side edge detection unit 305 has an illumination unit 63 and a line sensor 61, and the illumination unit 63 and the line sensor 61 are arranged to face each other across the receiving path 81 (see FIG. 1). The side edge detection unit 305 is arranged upstream of the punch unit 62 in the sheet transport direction D1. The inlet sensor 27 is arranged upstream of the side edge detection unit 305 in the sheet transport direction D1, and changes a signal when a leading edge 506 (see FIG. 5(a)), which is the downstream edge of the sheet in the sheet transport direction D1, passes through the inlet sensor 27.

[0029] The line sensor 61 as a detection unit extends in the width direction of the sheet SH, which is perpendicular to the sheet conveying direction D1, and changes a signal as an output value based on the position of the edge of the sheet SH in the width direction. More specifically, the line sensor 61 is composed of an optical sensor, and changes its output value based on the boundary position of the difference in density on the line sensor 61 that appears when light irradiated from the illumination unit 63 is blocked by the sheet SH. This makes it possible to detect the position of the side edge, which is the edge in the width direction of the sheet SH.

[0030] Punch unit 62, which serves as a punching section, is a rotary punch unit and includes punch 202 that rotates in the R1 direction around axial center 201 as an axis, and die 205 that rotates in the R2 direction opposite to the R1 direction around axial center 204. Gears (not shown) with the same number of teeth are provided at axial centers 201 and 204, respectively, and these gears mesh with each other. More specifically, drive from punch motor M1 is input to a gear provided at axial center 204 of die 205, and this gear meshes with a gear provided at axial center 201 of punch 202.

[0031] As a result, the punch 202 and the die 205 are rotated synchronously by the punch motor M1 so that the cutting edge 202a of the punch 202 fits into the hole 205a of the die 205. The punch motor M1 is configured to drive the cutting edge 202a of the punch 202 so that the circumferential speed of the cutting edge 202a is the same as the speed of the sheet SH in the sheet conveying direction D1, thereby enabling punching while conveying the sheet SH. The punch motor M1 is configured as a stepping motor, but may also be configured as a motor of another drive type, such as a DC brushless motor.

[0032] FIG. 2(a) is a schematic diagram showing the punch 202 positioned at the punching start position. FIG. 2(b) is a schematic diagram showing the punch 202 positioned at the punching completion position. FIG. 2(c) is a schematic diagram showing the punch 202 positioned at the separation position. The punch 202 rotates in the R1 direction. It starts to contact the sheet SH at the punching start position shown in FIG. 2(a) and engages with the die 205 at the punching completion position shown in FIG. 2(b). The punch 202 then separates from the sheet SH at the separation position shown in FIG. 2(c). After the leading edge of the sheet SH is detected by the inlet sensor 27, the punch 202 is rotated at a predetermined timing, allowing the sheet SH to be perforated at various hole pitches while being conveyed.

[0033] The rotational position of the punch 202 is detected by a punch position sensor S1. The punch unit 62 is provided with a light-shielding plate (not shown) that rotates integrally with the punch 202. The punch position sensor S1 changes its output signal when the light path is blocked or opened by the light-shielding plate. For example, in this embodiment, while the punch 202 is positioned in the R1 direction from the punching start position to the separated position, the light path of the punch position sensor S1 is blocked by a fan-shaped light-shielding plate. That is, when the punch 202 is positioned at the punching start position, the light path of the punch position sensor S1 begins to be blocked by the light-shielding plate, and when the punch 202 is positioned at the separated position, the light path of the punch position sensor S1 begins to be opened.

[0034] The rotational position of the punch 202 is detected by a punch position sensor S1, and the rotational position is controlled by pulses from a punch motor M1, which is a stepping motor. In this embodiment, the punch 202 is configured to wait at a home position upstream in the R1 direction from the punching start position.

[0035] The punching processing section 4A is also provided with a shift unit (not shown) for shifting the punch unit 62 in a width direction W (see FIG. 5A) perpendicular to the sheet conveying direction D1. In this embodiment, the width direction W as the intersecting direction is a direction perpendicular to the sheet conveying direction D1, but it may be any direction intersecting the sheet conveying direction D1. As shown in FIG. 7A, the shift unit has a punch base 70 as a moving part that holds the punch unit 62 and is movable together with the punch unit 62 in the width direction W, and a feed screw mechanism (not shown) that moves the punch base 70 in the width direction W. The feed screw mechanism is driven by a shift motor M2. Instead of the feed screw mechanism, the punch base 70 may be moved in the width direction W by a gear train, a belt, or the like driven by the shift motor M2.

[0036] The punch unit 62 and punch base 70 move in the forward direction by rotating the shift motor M2 forward, and move in the reverse direction, which is opposite to the forward direction, by rotating the shift motor M2 backward. These forward and reverse directions are parallel to the width direction W. By moving in the forward direction from the width direction home position, the punch unit 62 approaches the center of the conveying path (receiving path 81) in the width direction W. By moving in the reverse direction from the width direction home position, the punch unit 62 moves away from the center of the conveying path (receiving path 81) in the width direction W. The shift motor M2 is a pulse motor, and the position of the punch unit 62 in the width direction W is managed by the number of pulses input to the shift motor M2, with the width direction home position as a reference.

[0037] [Control system] Next, a control system of the post-processing device 4 according to this embodiment will be described. Fig. 3 is a block diagram showing the functional blocks of the post-processing device 4, and Fig. 4 is a block diagram showing the hardware configuration of the post-processing device 4. As shown in Figs. 3 and 4, the post-processing device 4 has a controller 301, an engine control unit 302, and a post-processing control unit 303, and the post-processing control unit 303 has functional blocks such as a conveyance control unit 309, a sensor control unit 310, and a punch control unit 308.

[0038] The conveyance control unit 309 controls the conveyance of the sheet SH, and the sensor control unit 310 detects the side edge 507 (see FIG. 5(b)) as the end of the sheet SH in the width direction W. The punch control unit 308 controls the punch unit 62 so that a hole is punched at a desired position in the sheet SH.

[0039] The post-processing control unit 303 has a hardware configuration including a CPU 320, a ROM 321, and a RAM 322. The CPU 320 reads out and performs calculations on various programs stored in the ROM 321. The RAM 322 is used as a work area for the CPU 320.

[0040] An image transmitted from an external device 300 such as a server or a computer is expanded and adjusted by a controller 301, which then instructs an image forming operation to an engine control unit 302. An instruction as to whether or not to punch a sheet SH is given from a touch panel (not shown) attached to the image forming apparatus 1, the image reading device 2, or the document feeder 3, or from the external device 300, and is sent to a post-processing control unit 303 via the controller 301.

[0041] The post-processing control unit 303 is connected to the entrance sensor 27, lighting unit 63, line sensor 61, punch motor M1, punch position sensor S1, shift motor M2, shift sensor S2, etc. An ON signal or an OFF signal is output from the entrance sensor 27 to the post-processing control unit 303. An ON signal or an OFF signal is output from the post-processing control unit 303 to the lighting unit 63. A timing signal indicating the start timing of detection by the line sensor 61 is output from the post-processing control unit 303 to the line sensor 61, and image data is output from the line sensor 61 to the post-processing control unit 303.

[0042] A drive signal is output from the post-processing control unit 303 to the punch motor M1 via a motor driver. Similarly, a drive signal is output from the post-processing control unit 303 to the shift motor M2 via a motor driver. A sensor signal consisting of an ON (High) signal or an OFF (Low) signal is output from the punch position sensor S1 to the post-processing control unit 303. When the optical path of the punch position sensor S1 is blocked by the above-mentioned light blocking plate, an ON (High) signal is output from the punch position sensor S1. When the optical path is open, an OFF (Low) signal is output from the punch position sensor S1.

[0043] Similarly, a sensor signal consisting of an ON (High) signal or an OFF (Low) signal is output from the shift sensor S2 to the post-processing control unit 303. As shown in FIGS. 7(a) to 7(c), a light-shielding portion 70a is provided on the punch base 70. When the optical path of the shift motor M2 consisting of an optical sensor is blocked by the light-shielding portion 70a, an ON (High) signal is output from the shift sensor S2, and when the optical path is open, an OFF (Low) signal is output from the shift sensor S2. In other words, the shift sensor S2 as a movement detection portion changes the signal as an output value based on the position of the punch base 70.

[0044] [Punch action] Next, the punching operation on a sheet SH will be described. In this embodiment, the case where the sheet SH is skewed and in a two-hole punching mode in which two holes are punched in one sheet SH will be described as an example. In FIGS. 5(a) to 5(d) and 6(a) to 6(d), reference numeral 250 indicates the center of the punch 202 at the punching completion position (hereinafter referred to as punch center 250). Target positions P1 and P2 shown on the sheet SH are target positions of holes punched by the punch 202 and are indicated by dashed lines. For example, when holes are punched at target positions P1 and P2, holes P1' and P2' are indicated by solid lines. Target position P1 is located downstream of target position P2 in the sheet conveying direction D1 and is the position of the first hole to be punched in the sheet SH. Target position P2 is the position of the second hole to be punched in the sheet SH.

[0045] When the punching operation to punch holes P1' and P2' in the sheet SH begins, as shown in Figure 5(a), the leading edge 506 of the sheet SH being transported by the inlet rollers 21 is detected by the inlet sensor 27, and the signal from the inlet sensor 27 changes. At this stage, holes P1' and P2' in the sheet SH have not yet been punched, so they are shown by dashed lines. At this time, the transport control unit 309 of the post-processing control unit 303 detects that the sheet SH has reached the punch area, and instructs the sensor control unit 310 to prepare for edge detection of the sheet SH and the punch control unit 308 to prepare for the punching operation.

[0046] 5B, when the sheet SH is further conveyed by the inlet rollers 21, the target position P1 reaches the line sensor 61. The line sensor 61 detects the difference in density at the boundary between the area covered by the sheet SH and the area not covered by the sheet SH, thereby detecting the position of the side edge 507 in the width direction W of the sheet SH that is located at a position where the target position P1 and the line sensor 61 overlap in the sheet conveyance direction D1.

[0047] The post-processing control unit 303 determines that the target position P1 has reached the line sensor 61 a predetermined time after the leading edge 506 of the sheet SH is detected by the inlet sensor 27. This predetermined time is set according to a preset target position of the hole. Furthermore, when the sheet SH is skewed, the timing at which the leading edge 506 is detected differs slightly compared to when the sheet SH is not skewed, but the error in the output value of the line sensor 61 due to this difference in detection timing is so small that it can be ignored.

[0048] The post-processing control unit 303 calculates a first movement distance of the punch unit 62 based on the punch center 250 of the punch unit 62, the position of which is managed by the shift sensor S2 and the shift motor M2, and the position of the side edge 507 detected by the line sensor 61. The first movement distance is the difference in the width direction W between the punch center 250 and the position of the side edge 507 detected in FIG. 5(b).

[0049] Next, as shown in Fig. 5(c), the post-processing control unit 303 drives the shift motor M2 to move the punch unit 62 a first movement distance in the width direction W, thereby aligning the punch center 250 with the target position P1 in the width direction W. The movement of the punch unit 62 in the width direction W is completed before the target position P1 reaches the punch center 250 and before the cutting edge 202a (see Fig. 2(a)) of the punch 202 rotated by the punch motor M1 comes into contact with the sheet SH.

[0050] 5(d) is a plan view showing a state in which the punch center 250 coincides with the target position P1 and a hole P1' has been punched by the punch 202. In this state, the punch 202 is located at the punching completion position, and the punch 202 is driven by the punch motor M1 in accordance with this timing.

[0051] 6A, when the sheet SH is further conveyed by the inlet rollers 21, the target position P2 reaches the line sensor 61. The line sensor 61 detects the difference in density at the boundary between the area covered by the sheet SH and the area not covered by the sheet SH, thereby detecting the position of the side edge 507 in the width direction W of the sheet SH that is located at a position where the target position P2 and the line sensor 61 overlap in the sheet conveyance direction D1.

[0052] Then, the post-processing control unit 303 calculates a second movement distance of the punch unit 62 based on the punch center 250 of the punch unit 62 and the position of the side edge 507 detected by the line sensor 61. The second movement distance is the difference in the width direction W between the punch center 250 and the position of the side edge 507 detected in FIG. 6(a).

[0053] Next, as shown in Fig. 6(b), the post-processing control unit 303 drives the shift motor M2 to move the punch unit 62 a second movement distance in the width direction W, thereby aligning the punch center 250 with the target position P2 in the width direction W. The movement of the punch unit 62 in the width direction W is completed before the target position P1 reaches the punch center 250 and before the cutting edge 202a (see Fig. 2(a)) of the punch 202 rotated by the punch motor M1 comes into contact with the sheet SH.

[0054] 6(c) is a plan view showing a state in which the punch center 250 coincides with the target position P2 and a hole P2' has been punched by the punch 202. In this state, the punch 202 is located at the punching completion position, and the punch 202 is driven by the punch motor M1 in accordance with this timing.

[0055] Fig. 6(d) is a plan view showing the state after the trailing edge 508 of the sheet SH has passed the line sensor 61. The sheet SH has holes P1' and P2' formed at the target positions P1 and P2. In Fig. 6(d), the shift motor M2 is not driven after punching at the target position P2, but the shift motor M2 may be driven to return the punch unit 62 to the widthwise home position (see Fig. 5(a)) in preparation for the next sheet reaching the punch area.

[0056] As described above, by detecting the position of the side edge 507 of the sheet SH by the line sensor 61 for each of the target positions P1 and P2, the position of the punch unit 62 in the width direction W can be adjusted with high precision, and holes can be punched as intended at the target positions P1 and P2. If there are three or more holes to be punched in the sheet SH, the above-described operation is repeated.

[0057] [Cleaning unit] Next, a cleaning unit 410 that cleans the line sensor 61 will be described with reference to Figures 7(a) to (c). As shown in Figure 7(a), the line sensor 61 has a transparent member 161 having a detection surface 161a that faces the surface of the sheet conveyed by the inlet rollers 21 (see Figure 1), and a plurality of light receiving elements 162 that are arranged in the width direction W and receive light that has passed through the transparent member 161. Note that, as the line sensor 61, for example, a CIS (Contact Image Sensor), a CCD (Charge Coupled Device) sensor, or a CMOS (Complementary Metal Oxide Semiconductor) sensor may be used.

[0058] The cleaning unit 410 has an arm 401 that rotates around a rotation shaft 403, a nonwoven fabric 400 supported on one end of the arm 401, and a coil spring 402 that biases the arm 401. The other end of the arm 401 is provided with a contact portion 401a that can contact the punch base 70. The other end of the arm 401 is located on the opposite side of the rotation shaft 403 from the one end to which the nonwoven fabric 400 is attached. The arm 401 is biased by the coil spring 402 around the rotation shaft 403 in the R4 direction shown in FIG. 7(b), and is positioned at the standby position shown in FIG. 7(a) by hitting a stopper (not shown).

[0059] The punch base 70 that holds the punch unit 62 has a light-shielding portion 70a that extends in the width direction W, and a pressing portion 70b that can press the contact portion 401a of the arm 401. As shown in FIG. 7(a), when the punch unit 62 and the punch base 70 are located at their width-direction home positions and the arm 401 of the cleaning unit 410 is located at the standby position, the pressing portion 70b is separated from the contact portion 401a.

[0060] When the punch unit 62 and punch base 70 move in the Rvs direction due to the reverse rotation of the shift motor M2, the pressing portion 70b of the punch base 70 presses the contact portion 401a of the arm 401, as shown in FIG. 7(b). This causes the arm 401 to rotate in the R3 direction around the rotation shaft 403 against the biasing force of the coil spring 402. In FIG. 7(b), the optical path of the shift sensor S2 is blocked by the light-blocking portion 70a, and the shift sensor S2 changes from OFF (Low) to ON (High). At this time, the nonwoven fabric 400 attached to the arm 401 begins to contact the detection surface 161a of the transparent member 161 of the line sensor 61.

[0061] Then, when the punch unit 62 and punch base 70 further move in the Rvs direction, the arm 401 further rotates in the R3 direction, as shown in FIG. 7(c). This causes the nonwoven fabric 400 to rub against the detection surface 161a, cleaning up the paper dust that has accumulated on the detection surface 161a. In this way, the arm 401, which functions as an interlocking unit and a rotating member, moves the nonwoven fabric 400, which functions as a cleaning unit, in conjunction with the movement of the punch unit 62 in the width direction W. The paper dust is discharged from the sheet SH being conveyed. The deposits that accumulate on the detection surface 161a are not limited to paper dust, but may also be fillers added to the sheet SH, dust, etc.

[0062] Here, the detection surface 161a can be divided into an area AR1 and an area AR2, and the area AR1 can be divided into an area AR11 and an area AR12. The area AR1 is an area from the left end 161L of the detection surface 161a to a position P11, and the position P11 is a position through which the side edge (left end) of a sheet of the smallest size that can be punched by the punch unit 62 passes. The area AR2 is an area from the position P11 to the right end 161R of the detection surface 161a. The area AR11 is an area from the left end 161L to a position P10, and the position P10 is a position through which the side edge (left end) of a sheet of the largest size that can be punched by the punch unit 62 passes. The area AR12, which is a predetermined area, is an area from the position P11 to the position P11.

[0063] The post-processing device 4 of this embodiment can punch holes in sheets of multiple sizes, and the position of the side edge (left edge) of a sheet passing over the line sensor 61 varies depending on the size of the sheet. Paper dust discharged from the sheet tends to accumulate in the area of ​​the detection surface 161a through which the sheet passes, i.e., areas AR12 and AR2. However, because area AR2 is an area through which the sheet passes regardless of its size, paper dust accumulated in area AR2 is removed by the sheet itself as it passes over the line sensor 61. For this reason, it is preferable that the nonwoven fabric 400 be configured to be able to clean at least area AR12. In this embodiment, the nonwoven fabric 400 is configured to be able to clean area AR1, which includes areas AR11 and AR12. On the other hand, for the reasons described above, the nonwoven fabric 400 does not clean area AR2.

[0064] When the punch control unit 308 (see FIG. 3) determines that cleaning of the line sensor 61 is necessary, it rotates the shift motor M2 in the reverse direction, swinging the nonwoven fabric 400 from the position shown in FIG. 7(a) to the position shown in FIG. 7(c), and then rotates the shift motor M2 in the forward direction. As a result, the punch unit 62 and punch base 70 return to the widthwise home position shown in FIG. 7(a), and the arm 401 rotates in the R4 direction due to the biasing force of the coil spring 402. The nonwoven fabric 400 then returns to the position shown in FIG. 7(a).

[0065] [Cleaning Control] Next, cleaning control by cleaning unit 410 will be described in more detail with reference to the flowchart in Fig. 8. Here, when shift sensor S2 is OFF, punch unit 62 is defined as being in the punch position correction area, and when shift sensor S2 is ON, punch unit 62 is defined as being in the sensor cleaning area. The punch position correction area is an area where punch unit 62 moves in the width direction W when punching, and the sensor cleaning area is adjacent to the punch position correction area in the width direction W and is an area where punch unit 62 moves in the width direction W when cleaning line sensor 61.

[0066] When cleaning control is started, the post-processing control unit 303 starts initialization of the post-processing device 4 (step S601). Cleaning control is started, for example, when power is turned on to the post-processing device 4, and initialization of the post-processing device 4 includes cleaning of the line sensor 61 and movement operation of the punch unit 62 to the home position in the rotation direction.

[0067] Next, the post-processing control unit 303 checks whether there is any remaining paper remaining in the post-processing device 4 (step S602) and determines whether there is any remaining paper (step S603). If there is any remaining paper (step S603: Yes), the post-processing control unit 303 notifies the user that there is any remaining paper, for example, on a touch panel (step S604), and ends the process.

[0068] If there is no remaining paper (step S603: No), cleaning control by the cleaning unit 410 continues, and the punch unit 62 starts returning to its widthwise home position (step S605). That is, the post-processing control unit 303 determines whether the shift sensor S2 is ON (step S606). If the shift sensor S2 is ON (step S606: Yes), the post-processing control unit 303 starts the forward rotation of the shift motor M2 (step S607) and determines whether the shift sensor S2 has turned OFF (step S608). If the shift sensor S2 remains ON (step S608: No), the forward rotation of the shift motor M2 continues.

[0069] If the shift sensor S2 is turned off in step S608, or if the shift sensor S2 was originally off in step S606 (step S606: No), proceed to step S609. At this time, the punch unit 62 has completed returning to the home position in the width direction and is therefore located within the punch position correction area.

[0070] Next, the post-processing control unit 303 starts reverse rotation of the shift motor M2 to move the punch unit 62 to the sensor cleaning area (step S609). Then, the post-processing control unit 303 determines whether the shift sensor S2 is ON (step S610). If the shift sensor S2 remains OFF (step S610: No), the shift motor M2 continues to rotate reversely. In other words, the shift motor M2 as a drive source is driven based on the output value of the shift sensor S2 to move the punch base 70 in the width direction W.

[0071] If the shift sensor S2 changes from OFF to ON (step S610: Yes), the post-processing control unit 303 continues the reverse rotation of the shift motor M2 for an additional time T1 after the shift sensor S2 turns ON. Note that, before the shift sensor S2 turns ON, the pressing portion 70b of the punch base 70 starts pressing the abutting portion 401a of the arm 401 of the cleaning unit 410. As a result, the arm 401 rotates in the R3 direction, and the nonwoven fabric 400 moves to the cleaning completion position shown in FIG. 7(c), completing cleaning of the detection surface 161a of the line sensor 61. After the time T1 has elapsed, the post-processing control unit 303 stops driving the shift motor M2 (step S611).

[0072] Next, the post-processing control unit 303 rotates the shift motor M2 forward again to move the punch unit 62 toward the widthwise home position in the punch position correction area (step S612). Then, the post-processing control unit 303 determines whether the shift sensor S2 has turned OFF (step S613). If the shift sensor S2 remains ON (step S613: No), the shift motor M2 continues to rotate forward.

[0073] If the shift sensor S2 changes from ON to OFF (step S613: Yes), the post-processing control unit 303 continues the forward rotation of the shift motor M2 for an additional time T2 and then stops the shift motor M2 (step S614). As a result, the punch unit 62 stops at the width-direction home position within the punch position correction area. This completes the cleaning control.

[0074] 8, the cleaning control of the cleaning unit 410 has been described using the example of when the post-processing device 4 is turned on, but the present invention is not limited to this. For example, the processes in steps S605 to S614 may be performed when a job for punching holes in a sheet is started or after the job is completed. Also, the number of sheets passing through the line sensor 61 may be counted, and the detection surface 161a of the line sensor 61 may be cleaned at every predetermined count.

[0075] As described above, by providing the cleaning unit 410 in the post-processing device 4 and cleaning the detection surface 161a of the line sensor 61 with the cleaning unit 410, it is possible to improve the detection accuracy of the side edge 507 of the sheet by the line sensor 61. This improves the positioning accuracy of the punch unit 62 in the width direction W, and enables the sheet to be punched with high accuracy.

[0076] Furthermore, in this embodiment, the punch unit 62 is moved in the width direction W by the shift motor M2, and the nonwoven fabric 400 is moved in conjunction with the shift motor M2 via the arm 401. Therefore, even without providing a separate motor for moving the nonwoven fabric 400, the nonwoven fabric 400 can be moved by the shift motor M2, thereby achieving a more compact and cost-effective device.

[0077] Furthermore, in this embodiment, the cleaning unit 410 is configured to clean only the area AR1 of the detection surface 161a of the line sensor 61, and not the area AR2, thereby reducing the time it takes to clean the line sensor 61.

[0078] <Second embodiment> Next, a second embodiment of the present invention will be described. The second embodiment differs from the first embodiment in the area of ​​the detection surface 161a of the line sensor 61 that is cleaned by the nonwoven fabric 400. Therefore, the same components as those in the first embodiment will not be shown in the drawings or will be described with the same reference numerals in the drawings.

[0079] 9, in this embodiment, nonwoven fabric 400 cleans the entire area AR20 of detection surface 161a of line sensor 61. That is, the cleaning area of ​​detection surface 161a by nonwoven fabric 400 can be arbitrarily adjusted depending on the length of nonwoven fabric 400, the distance from pivot shaft 403 to contact portion 401a and nonwoven fabric 400, the positional relationship between light-shielding portion 70a of punch base 70 and shift sensor S2, etc.

[0080] As described above, by providing the cleaning unit 410 in the post-processing device 4 and cleaning the entire area AR20 of the detection surface 161a of the line sensor 61 with the cleaning unit 410, it is possible to improve the detection accuracy of the side edge 507 of the sheet by the line sensor 61. This improves the positioning accuracy of the punch unit 62 in the width direction W, and enables the sheet to be punched with high precision.

[0081] <Other embodiments> In any of the above-described embodiments, the cleaning control of the line sensor 61 by the cleaning unit 410 involves only one reciprocating movement of the nonwoven fabric 400 over the detection surface 161a, but this is not limited to this. For example, the nonwoven fabric 400 may reciprocate multiple times over the detection surface 161a by repeating steps S609 to S613 in FIG. 8.

[0082] Furthermore, in all of the above-described embodiments, the punch base 70 directly presses the arm 401, causing the arm 401 to rotate and cleaning the line sensor 61 with the nonwoven fabric 400; however, the present invention is not limited to this. For example, the punch base 70 and the arm 401 may be connected to each other by a gear train, and the arm 401 may rotate in conjunction with the movement of the punch unit 62 and the punch base 70. Furthermore, the nonwoven fabric 400 is not limited to being rotated about the rotation shaft 403 by the arm 401, and may be attached to a sliding member, for example, so as to slide in the width direction W.

[0083] In addition, in all of the above-described embodiments, the nonwoven fabric 400 of the cleaning unit 410 is linked to the movement of the punch unit 62 and the punch base 70 in the width direction W, but this is not limiting. For example, the arm 401 may be driven by a motor other than the shift motor M2 to swing the nonwoven fabric 400. For example, the conveying motor M3 may be used as the motor for driving the arm 401, or a new motor may be added.

[0084] In addition, in all of the above-described embodiments, nonwoven fabric 400 is used as the cleaning unit that removes paper dust, but this is not limited to this. For example, woven fabric, a flocked sheet, or other materials may be used instead of nonwoven fabric 400, and the material is not limited. However, it is preferable that the cleaning unit that removes paper dust does not damage the detection surface 161a of the line sensor 61 and does not become charged.

[0085] In addition, although the above-described embodiments have been described using an electrophotographic image forming apparatus 1, the present invention is not limited to this. For example, the present invention can also be applied to an inkjet image forming apparatus that forms an image on a sheet by ejecting ink liquid from nozzles.

[0086] The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that realizes one or more functions. [Explanation of symbols]

[0087] 1: Image forming apparatus / 1B: Image forming unit / 1S: Image forming system / 4: Sheet processing device (post-processing device) / 21: Conveying unit (inlet roller) / 24: Reversing unit (reversing roller) / 26: Rotating body pair (inner discharge roller) / 31: Stacking unit (intermediate lower guide) / 36: Discharge unit (bundle discharge roller) / 61: Detection unit (line sensor) / 62: Perforation unit (punch unit) / 70: Moving unit (punch base) / 81: First conveying path (receiving path) / 82: Second conveying path (inner discharge path) ) / 84: third conveying path (second discharge path) / 161: transparent member / 161a: detection surface / 162: light receiving element / 201: shaft (shaft center) / 202: punch / 400: cleaning unit (nonwoven fabric) / 401: interlocking unit, rotating member (arm) / 403: rotating shaft / 507: end (side end) / AR12: area / AR20: entire area / D1: sheet conveying direction / P10, P11: position / M2: drive source (shift motor) / S2: movement detection unit (shift sensor) / W: cross direction (width direction)

Claims

1. a conveying section that conveys the sheet in a sheet conveying direction; a punching unit that punches holes in the sheet conveyed by the conveying unit; a moving unit that moves the punching unit in a direction intersecting the sheet conveying direction; a detection unit that is disposed upstream of the punching unit in the sheet conveying direction and that changes an output value based on the position of an end of the conveyed sheet in the cross direction; a cleaning unit that cleans the detection unit; a linking unit that moves the cleaning unit in conjunction with movement of the punching unit in the cross direction, The cleaning unit cleans the detection unit by being moved by the interlocking unit. A sheet processing apparatus characterized by:

2. the interlocking portion supports the cleaning portion and moves together with the cleaning portion by being pressed by the moving portion; 2. The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is a sheet processing apparatus.

3. The interlocking portion is a rotating member that rotates around a rotation axis when pressed by the moving portion.

3. The sheet processing apparatus according to claim 2, wherein the sheet processing apparatus is a sheet processing apparatus.

4. the moving unit holds the punching unit and is movable together with the punching unit in the intersecting direction, a movement detection unit that changes an output value based on the position of the moving unit; a drive source that drives the moving unit based on the output value of the movement detection unit and moves the moving unit in the intersecting direction, 4. The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is a sheet processing apparatus.

5. the detection unit is a line sensor including a transparent member having a detection surface facing a surface of the sheet conveyed by the conveyance unit, and a plurality of light receiving elements arranged in the intersecting direction and receiving light that has passed through the transparent member, The cleaning unit cleans the detection surface.

5. The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is a sheet processing apparatus.

6. the cleaning unit cleans at least a predetermined area on the detection surface between a position where the end of a sheet of the smallest size that can be punched by the punching unit passes and a position where the end of a sheet of the largest size that can be punched by the punching unit passes.

6. The sheet processing apparatus according to claim 5, wherein the sheet processing apparatus is a sheet processing apparatus.

7. The cleaning unit cleans the entire detection surface.

6. The sheet processing apparatus according to claim 5, wherein the sheet processing apparatus is a sheet processing apparatus.

8. The cleaning unit removes deposits on the detection surface.

8. The sheet processing apparatus according to claim 5, wherein the sheet processing apparatus is a sheet processing apparatus.

9. The deposit is paper dust discharged from the sheet.

9. The sheet processing apparatus according to claim 8, wherein the sheet processing apparatus is a sheet processing apparatus.

10. the punching unit punches holes in the sheet while it is being conveyed by the conveying unit; 10. The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is a sheet processing apparatus.

11. The punching unit has a punch that rotates around an axis extending in the intersecting direction.

11. The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is a sheet processing apparatus.

12. a first conveying path for receiving a sheet; a reversing unit that reverses the sheet received from the first conveying path; a stacking section on which the sheets inverted by the inverting section are stacked; a second conveying path extending below the first conveying path, receiving the sheet inverted by the inverting unit, and guiding the sheet to the stacking unit; A discharge section that discharges the sheet outside the machine; a third conveying path extending from the stacking portion toward the discharge portion and guiding the sheet to the discharge portion; a pair of rotating bodies that are arranged in the second conveying path and that discharge the sheet to the stacking portion, 12. The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is a sheet processing apparatus.

13. the perforation unit is disposed on the first transport path; The sheet processing apparatus according to claim 12 .

14. a sheet processing apparatus according to any one of claims 1 to 13; an image forming unit that forms an image on a sheet, An image forming system comprising:

Images