JP2007031119A - Offset stacking device for sheets and image forming device equipped with stacking device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make offset motions in a plurality of places using a simple structure. <P>SOLUTION: An offset stacking device 400 for sheets is equipped with a post-treatment tray 410 whereon the ejected sheets are stacked, an offset roller 407 to move the sheets stacked on the post-treatment tray 410 to a plurality of offset positions in the direction intersecting the sheet ejecting direction, and a clamping pawl and a sheet bundle ejecting member to move the sheets moved by the offset roller 407 to downstream side in the sheet ejecting direction of the post-treatment tray 410. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sheet offset stacking apparatus for offset stacking sheets, and an image forming apparatus including the sheet offset stacking apparatus in an apparatus main body.

  Conventionally, in an image forming apparatus that forms an image on a sheet, the upstream end in the sheet discharge direction of the sheet discharged from the apparatus main body of the image forming apparatus is aligned, and the sheet is offset and moved in a direction crossing the sheet conveyance direction. Some have a sheet aligning device (see FIG. 19).

  The sheet aligning apparatus 900 first discharges a sheet sent from an apparatus main body (not shown) of the image forming apparatus to a staple tray 902 by a discharge roller pair 901. Then, the paddle 903 having elasticity rotates counterclockwise in FIG. 19 to move the sheet on the staple tray 902 to the upstream side in the sheet discharge direction, and the nip between the staple tray 902 and the alignment belt 904 having elasticity. To send. The alignment belt 904 rotates in synchronization with the discharge roller pair 901, moves the sheet to the upstream side in the sheet discharge direction following the paddle 903, and abuts against the stopper 905. The stopper 905 receives the upstream end of the sheet in the sheet conveyance direction.

  Thereafter, the sheet discharged following the staple tray 902 is also brought into contact with the stopper 905 in the same manner. As a result, a predetermined number of sheets are stacked on the staple tray 902 to form a bundle. Then, the pair of discharge rollers 907 that have been separated so far rotate while sandwiching the sheet bundle, and discharge to the discharge tray 906.

  The sheet aligning apparatus 900 is configured so that the sheet bundle can be offset and discharged onto the discharge tray 906 for offset stacking. The offset stacking refers to stacking the subsequent sheet bundle with the position shifted in the direction (width direction) intersecting the sheet discharge direction with respect to the sheet bundle previously discharged to the discharge tray 906.

  To offset the sheets, the width aligning plate 908 moves in the sheet width direction after the sheets are abutted against the stopper 905. The width alignment plate 908 presses the side edge of the sheet while moving in the width direction, and presses the other side edge of the sheet against the fixed orthogonal regulating plate 909. For this reason, the position of the sheet is shifted in the width direction with respect to the sheet bundle previously discharged to the discharge tray 906. The width alignment plate 908 shifts the position in the width direction in the same manner for the next sheet to be discharged.

  A predetermined number of sheets shifted in the width direction are stacked on the staple tray 902 to form a bundle. The sheet bundle is discharged to a discharge tray 906 by a discharge roller pair 907. As a result, the sheet bundle is stacked with its position shifted in the width direction with respect to the sheet bundle previously discharged to the discharge tray 906. That is, the sheet bundle is in an offset stacking state.

JP 2002-187666 A

  However, the conventional sheet offset stacking apparatus 900 has a complicated structure because the sheet is taken over by the paddle 903 and the alignment belt 904 and conveyed upstream in the sheet discharge direction, and the upstream end of the sheet is pressed against the stopper 905. It was.

  Further, since the conventional sheet offset stacking apparatus 900 presses the sheet against the orthogonal side regulation plate 909 by the width alignment plate 908 and performs offset stacking, the offset operation can be performed only at one place. For this reason, when there are many types of sheet bundles, the offset sheet bundles need to be taken out several times and the sheet bundle sorting efficiency is poor.

  In addition, the conventional image forming apparatus provided with the sheet offset stacking apparatus that needs to take out the offset sheet bundle in several times needs to stop the image forming operation every time the offset sheet bundle is taken out, The image forming operation efficiency was poor.

  An object of the present invention is to provide a sheet offset stacking apparatus capable of performing offset operations at a plurality of locations with a simple structure.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that includes a sheet offset stacking apparatus that can perform offset operations at a plurality of locations and that does not need to perform image forming operations in several steps.

  In order to achieve the above object, a sheet offset stacking apparatus according to the present invention includes a sheet stacking unit on which discharged sheets are stacked, and the sheet stacked on the sheet stacking unit in a direction intersecting the sheet discharge direction. A sheet conveying unit configured to move to a plurality of offset positions; and a sheet moving unit configured to move a sheet moved by the sheet conveying unit to a downstream side of the sheet stacking unit in the sheet discharging direction.

  The sheet offset stacking apparatus according to the present invention includes a side end aligning unit that receives a side end of the sheet moved in the intersecting direction by the sheet conveying unit along the sheet discharge direction, and the sheet moving unit includes: The sheet is once brought into contact with the side edge aligning means and then moved from the side edge aligning means to any one of a plurality of offset positions.

  The sheet offset stacking apparatus of the present invention includes an upstream end receiving unit that is disposed upstream of the sheet discharging direction and receives an upstream end of the sheet, and the sheet conveying unit discharges the sheet. When waiting on the sheet stacking means, and when the sheet is discharged to the sheet stacking means, it contacts the upper surface of the sheet, conveys the sheet to the upstream side in the sheet discharge direction, and the upstream It is possible to contact the end receiving means.

  In the sheet offset stacking apparatus of the present invention, the sheet moving unit is also used as a sheet holding unit that holds the sheets stacked on the sheet stacking unit.

  The sheet offset stacking apparatus of the present invention includes offset position setting means for setting the plurality of offset positions by an external operation.

  In order to achieve the above object, an image forming apparatus of the present invention includes an image forming unit that forms an image on a sheet, a sheet stacking unit that discharges and stacks a sheet on which an image is formed by the image forming unit, A sheet conveying unit configured to move the sheets stacked on the sheet stacking unit to a plurality of offset positions in a direction intersecting with the sheet discharge direction; and the sheet moved by the sheet conveying unit as the sheet of the sheet stacking unit. Sheet moving means for moving to the downstream side in the discharge direction.

  In order to achieve the above object, an image forming apparatus according to the present invention includes: an image forming unit that forms an image on a sheet; and a sheet offset stacking device that offset stacks a sheet on which an image is formed by the image forming unit. The sheet offset stacking apparatus is any one of the above sheet offset stacking apparatuses.

  In the sheet offset stacking apparatus according to the present invention, the sheet conveying unit moves the sheet to a plurality of offset positions in a direction intersecting the sheet discharge direction, so that the offset operation is performed at the plurality of offset positions. And the number of sheet bundles can be increased. As a result, the sheet offset stacking apparatus of the present invention can improve the sorting efficiency of the sheet bundle.

  Since the sheet offset stacking apparatus of the present invention includes the side edge aligning means for receiving the side edge of the sheet moved in the intersecting direction, each offset position is reliably set based on the side edge aligning means. can do.

  The sheet offset stacking apparatus of the present invention waits above the sheet stacking unit when the sheet is discharged, and when the sheet is discharged to the sheet stacking unit, the sheet is transferred in the sheet discharge direction. Since it can be conveyed upstream and brought into contact with the upstream end receiving means, the upstream ends of the sheets stacked on the sheet stacking means can be reliably aligned one by one.

  In the sheet offset stacking apparatus of the present invention, since the moving unit is also used as the sheet holding unit that holds the sheets stacked on the sheet stacking unit, even if the succeeding sheet is discharged onto the preceding sheet, the preceding unit Sheet misalignment can be prevented and consistency can be maintained. Also, since the moving means can hold and move the sheet to the downstream side, it can be moved and discharged while maintaining the integrity of the sheet, and the sorting of the offset sheet bundle can be made clear. Can do.

  Since the sheet offset stacking apparatus of the present invention includes setting means for setting a plurality of offset positions by external operation, the offset positions can be freely selected, and sheets can be offset stacked at a desired position. it can.

  The image forming apparatus of the present invention includes a sheet offset stacking apparatus that can perform offset operations at a plurality of offset positions. Therefore, it is not necessary to perform the image forming operation in several steps, and the image forming operation efficiency can be improved. it can.

  Hereinafter, a sheet offset stacking apparatus according to an embodiment of the present invention and an image forming apparatus including the sheet offset stacking apparatus in an apparatus main body, for example, a copier will be described with reference to the drawings.

  FIG. 1 is a front view of a schematic configuration of a copying machine including a sheet offset stacking apparatus according to the present invention in an apparatus main body.

  Examples of the image forming apparatus include a copying machine, a facsimile, a printer, and a complex machine of these. Therefore, the image forming apparatus is not limited to a copying machine.

  Further, the sheet offset stacking apparatus 400 of the present invention is not connected only to the apparatus main body 500A of the copying machine 500. The sheet offset stacking apparatus 400 is separate from the apparatus main body 500A of the copier 500, but may be incorporated in the apparatus main body 500A.

  Further, the sheet offset stacking apparatus according to the present embodiment includes the stapler unit 420 to bind the sheet bundle. However, instead of the stapler unit 420, the sheet offset stacking apparatus includes a punching device to punch holes in the sheet bundle. May be. Therefore, the sheet offset stacking device is not limited to binding a bundle of sheets. Furthermore, a stapler unit and a punching device are not necessarily required. The sheet offset stacking apparatus may have only a function for offset stacking of sheets.

  The copier 500 includes a reader unit 100, a printer unit 200, a sheet offset stacking device 400, and the like. An automatic document feeder 300 (hereinafter referred to as “ADF”) for supplying documents one by one onto the platen glass 102 is provided on the upper part of the apparatus main body 500A of the copying machine 500. A sheet offset stacking device 400 that performs post-processing of the sheets discharged from the copying machine 500 is connected to the side of the apparatus main body 500A of the copying machine 500.

  The copier 500 reads an image of a document supplied by the ADF 300 with the reader unit 100 or reads an image of a document placed on the platen glass 102 of the reader unit 100 with the reader unit 100 and prints the image on the printer. In addition to functioning as a copying machine for copying on a sheet by the unit 200, the printer unit 200 receives an image signal sent from an external personal computer and functions as a printer for forming the image signal on a sheet. Yes. Further, the copier 500 transmits an image signal read by the reader unit 100 to another facsimile, or receives a facsimile signal from another facsimile by the printer unit 200, and prints an image on a sheet based on the signal. It also functions as a facsimile machine to be formed. When the copier 500 is used only as a printer, there is no need to provide the automatic document feeder 300 and the reader unit 100.

  In FIG. 1, a reader unit 100 converts a document image into image data. The printer unit 200 has a plurality of types of sheet cassettes 204 and 205 on which a plurality of sheets are stacked, and outputs image data as a visible image on a sheet in accordance with a print command.

  When the document is conveyed to a predetermined position on the platen glass 102 by the ADF 300, the reader unit 100 turns on the lamp 103 of the reader unit 100 and moves the scanner unit 104 so that the lamp 103 irradiates the document. . The reflected light from the document is input to the CCD image sensor unit 109 through the mirrors 105, 106, 107 and the lens 108. The reflected light of the original irradiated to the CCD image sensor unit 109 is subjected to electrical processing such as photoelectric conversion in the CCD image sensor unit 109 and is subjected to normal digital processing. Thereafter, these image signals are input to the printer unit 200.

  The image signal input to the printer unit 200 is converted into an optical signal modulated by the exposure control unit 201 and irradiates the photosensitive drum 202. The latent image formed on the photosensitive drum 202 by this irradiation light is developed by the developing unit 203 to become a toner image. Then, in synchronization with the leading edge of the toner image, the sheet is conveyed from one of the sheet cassettes 204 and 205, and the toner image is transferred to the sheet by the transfer device 206. The transferred toner image is fixed on the sheet by the fixing unit 207. The sheet on which the toner image is fixed passes through a path 214 and is discharged from the sheet discharge unit 208 to the outside of the apparatus main body 500A of the copier 500. Thereafter, the sheets are sorted, bound, and the like according to an operation mode designated in advance by the sheet offset stacking apparatus 400. The exposure control unit 201, the photosensitive drum 202, the developing unit 203, the transfer unit 206, and the like constitute an image forming unit.

  Next, the order of forming sequentially read images on both sides of one sheet will be described.

  The sheet on which the toner image is fixed on one side by the fixing unit 207 is guided to the paths 215 and 218 by the direction switching members 209 and 217 held at the solid line positions, and by the direction switching member 213 held at the broken line positions. Guided to the reverse path 212. When the rear end of the sheet passes through the direction switching member 213, the direction switching member 213 switches to the solid line position. Then, the roller 211 reverses the rotation direction. As a result, the conveyance direction is reversed, the sheet is reversed (switchback conveyance), and is conveyed to the transfer paper stacking unit 210. Then, the sheet is sent to the photosensitive drum 202. When the next document is prepared on the platen glass 102, the image of the document is read in the same manner as the above process. The read image is transferred to the sheet supplied from the transfer paper stacking unit 210. In this way, two document images are formed on the front and back surfaces of the same sheet.

  FIG. 2 is an enlarged cross-sectional view for explaining the configuration of the sheet offset stacking apparatus 400 shown in FIG.

  The sheet offset stacking apparatus 400 includes a stapling function that is a binding operation by the staple unit 420 in addition to an offset stacking operation for sorting sheets.

  A schematic operation of the sheet offset stacking apparatus 400 will be described. The offset roller arm 406 is shown on both sides of the offset roller 407 in FIGS. 4 to 10, and is shown between the offset rollers 407 in FIGS. This is because the positions are made different for easy understanding of the operation explanation, and the offset roller arm 406 may be disposed at any position.

  In FIG. 2, a sheet receiving unit 401 receives a sheet discharged from the printer unit 200. The sheet received by the sheet receiving unit 401 is detected by the entrance sensor 403, conveyed by the conveyance roller 405, and then discharged onto, for example, a post-processing tray 410 that is a sheet stacking unit as illustrated in FIG. 3. A sheet bundle discharge sensor 415 (see FIG. 2) detects the sheets stacked on the post-processing tray 410.

  The sheet discharged as shown in FIG. 4 reaches the upstream end receiving means such as the trailing end stopper 411 by the rotation in the direction opposite to the sheet discharging direction of the offset roller 407 as the sheet conveying means as shown in FIG. Returned. Thereafter, as shown in FIG. 6, the offset roller 407 performs alignment operation by abutting the upstream end Pb of the sheet P in the sheet discharge direction against the trailing end stopper 411.

  As shown in FIG. 7, the offset roller 407 moves the sheet to, for example, a side end alignment wall 416 that is a side end alignment unit existing on the side of the stapler unit 420 (see FIG. 12) while being in contact with the sheet. Then, alignment of the side end portions Pa along the sheet discharge direction is performed (the width of the sheet is aligned).

  As shown in FIGS. 8 and 9, after the offset roller 407 is lifted by the pickup solenoid 433 (see FIG. 12), the aligned sheets are held in place by the clamp claws 412 and sequentially fed. It is designed not to be affected by the transporting by. The sequentially discharged sheets are aligned on the post-processing tray 410 by the offset roller 407 to form a sheet bundle. As shown in FIG. 10, the sheet bundle is bound by the staple unit 420 (see FIG. 12) when the staple mode is selected.

  Thereafter, as shown in FIG. 14, the sheet bundle is moved toward the stack tray 421 by the movement of the sheet bundle discharge member 413 while being held by the clamp claws 412. The clamp pawl 412 and the sheet bundle discharge member 413 constitute a sheet holding unit and a sheet moving unit. When the clamp claw 412 releases the sheet bundle on the stack tray 421, the sheet bundle is discharged onto the stack tray 421 and stacked.

  11 and 12 are diagrams showing a driving mechanism of the offset roller 407. FIG.

  The offset roller 407 is supported by an offset roller arm 406 that can move upward so that a sheet can be received on the processing tray 410. The offset roller arm 406 is lifted around the shaft 406a by the ON operation of the pickup solenoid 433. The offset roller 407 receives a rotational force via the belts 431a and 431b by the transport motor 431. When the conveyance motor 431 is rotated, the offset roller 407 conveys the sheet to the downstream side in the sheet conveyance direction (sheet discharge direction) by an amount corresponding to the rotation amount of the conveyance motor 431. Further, the offset roller 407 also rotates in the reverse direction in the direction in which the sheet is conveyed upstream in the sheet conveying direction (sheet discharging direction). The belt 431b is stretched over pulleys 422 and 422a.

  The pulley 422 needs to be able to move on the shaft 406a in the thrust direction together with the offset roller arm 406 and to receive a rotational force from the shaft 406a. For this reason, the axis 406a is an angular axis. Further, the pulley is formed with a square hole with which the square shaft is engaged. The offset roller arm 406 does not need to receive a rotational force from the shaft 406a. For this reason, the offset roller arm 406 is formed with a round hole through which the shaft 406a passes.

  When the sheet is conveyed on the processing tray 410 for a predetermined distance and the entrance sensor 403 (see FIG. 2) detects the trailing edge of the sheet, the pickup solenoid 433 is turned off. Then, the offset roller 407 descends by its own weight, contacts the sheet, and conveys the sheet to the downstream side in the sheet conveyance direction. The offset roller 407 stops the sheet after conveying the sheet to the downstream side in the sheet conveying direction, rotates in the reverse direction, and conveys the sheet to the upstream side in the sheet conveying direction. The sheet is abutted against the trailing end stopper 411 and aligned at the upstream end in the sheet conveying direction.

  The sheet bundle discharge member 413 installed in the vicinity of the rear end stopper 411 is configured such that power is transmitted through the pinion 435 and the rack 436 by the sheet bundle discharge motor 430. The sheet bundle discharge member 413 is fixed to the home position by excitation of the sheet bundle discharge motor 430. The clamp pawl 412 is opened and closed by a clamp solenoid 434. The clamp claw 412 opens when the offset roller 407 conveys the sheet downstream in the sheet conveying direction and stops rotating.

  Further, the offset roller 407 can be moved to the side end alignment wall 416 that serves as the alignment position reference of the sheet on the side where the stapler unit 420 is installed via the pinion 423 and the rack 424 by driving the offset motor 432. ing. For this reason, the offset roller 407 moves the sheet whose rear end is positioned at the rear end stopper 411 to the side end alignment wall 416 due to the frictional force between the sheet and the offset roller 407, and hits the sheet. It slides slightly and stops.

  Since the copying machine 500 to which the sheet offset stacking device 400 is attached knows the size of the sheet discharged from the sheet discharge unit 208 (see FIG. 1), the control unit of the sheet offset stacking device 400 composed of a microcomputer system. For example, the CPU 111 can grasp the size of the sheet conveyed on the processing tray 410 by serial communication with the control unit 501 of the copying machine 500. Therefore, the CPU 111 of the sheet offset stacking apparatus 400 grasps the sheet size every time the sheet is discharged from the copying machine 500, and rotates the offset motor 432 that moves the offset roller 407 in the width direction by the movement amount corresponding to the sheet size. It is supposed to let you. As a result, the offset roller 407 moves by an amount corresponding to the size of the sheets stacked on the processing tray 410 and can reliably press the side edge of the sheet against the side edge alignment wall 416. Yes.

  Further, in order to correct the deviation in the conveyance direction after moving in the sheet width direction, the offset roller 407 rotates again in the upstream direction in the sheet conveyance direction, and the alignment operation of the trailing edge of the sheet is completed. Yes. Thereby, highly accurate matching is realized. When the alignment process for the designated number of sheets is completed, the clamp pawl 412 is closed to hold the sheet bundle.

  A stapler unit 420 is disposed in the vicinity of the side end alignment wall 416 on the processing tray 410. The stapler unit 420 is capable of binding (stapling) a sheet bundle formed on the processing tray 410.

  The offset operation will be described with reference to FIGS.

  The first sorting operation is an operation in which the fed sheets are aligned one by one with the side edge alignment wall 416, and are bundled and discharged to the stack tray 421. The second and subsequent sorting operations are sheets. Are brought into contact with the side edge alignment wall 416 one by one, moved to the offset position, discharged onto the stack tray 421, and sheets are stacked on the stack tray 421.

  The offset operation will be described in detail.

  The first sorting operation is performed as follows. First, the offset roller 407 presses the sheets one by one against the side edge alignment wall 416 to form a sheet bundle with the side edges aligned. Next, the clamp claw 412 holds the sheet bundle. Then, as shown in FIG. 14, the sheet bundle discharge member 413 moves from the post-processing tray 410 to the stack tray 421 together with the clamp claws 412 that hold the sheet bundle. At this time, the sheet bundle moves while the side end is in contact with the side end alignment wall 416. Finally, the clamp pawl 412 is opened, and the sheet bundle is released and stacked on the stack tray 421. Thus, in the first sorting operation, the sheets are bundled and discharged to the stack tray 421. The position is a position along the side end alignment wall 416. In addition, since the sheet bundle stacked on the stack tray 421 constitutes a part of the post-processing tray 410, when the sheet bundle is discharged from the post-processing tray, the stack tray 421 is stacked on the stacked sheet bundle. Descends until the uppermost surface thereof substantially coincides with the post-processing tray 410. In other words, the stack tray 421 is lowered by substantially the thickness of the sheet bundle.

  The second sorting operation is performed as follows. The offset roller 407 once makes the first sheet contact the side edge alignment wall 416 and then moves the sheet by a predetermined distance (first offset distance) L1 from the side edge alignment wall 416 to move the sheet by a predetermined distance. Let Thereafter, the clamp claw 412 holds the sheet. Then, the sheet bundle discharge member 413 moves from the post-processing tray 410 to the stack tray 421 together with the clamp pawl 412 that holds the sheet. Finally, the clamp claw 412 is opened, and the sheet bundle is released and stacked on the first sheet bundle already stacked on the stack tray 421. At this time, the discharged first sheet is stacked at a position offset by a specified distance with respect to the first sheet bundle. Thereafter, the second sheet is stacked on the first sheet. The third and subsequent sheets are similarly stacked on the previously discharged sheet. Finally, the second sheet is bundled at a position offset by a specified distance with respect to the first sheet bundle and stacked on the first sheet bundle. When the stacking height of the second sheet reaches a certain level, the stack tray 421 is lowered by the height, and the uppermost surface of the sheets stacked on the stack tray 421 almost coincides with the post-processing tray 410. To do. Thus, the succeeding sheet does not push out the preceding sheet stacked on the stack tray 421.

  The third sort operation is performed in the same manner. However, the specified distance (first offset distance) from the side edge alignment wall 416 is set to be longer than the previous sheet bundle by the offset distance (L1 <L2 <L3).

  As a result, the sheet bundle is offset and stacked on the stack tray 421 at a plurality of locations (three locations in the example shown in FIG. 13).

  Note that the offset roller 407 is moved by rotating the pinion 423 rotated by the offset motor 432 and moving the rack 424.

  In the above description, the offset roller 407 moves the sheet to the offset position after the side end portion of the sheet is brought into contact with the side end alignment wall 416. This is because the side end alignment wall 416 is moved. In order to make the offset position accurate with respect to the reference, the side edge of the sheet may be moved from the beginning to the offset position without contacting the side edge alignment wall 416.

  FIG. 15 is a block diagram illustrating a configuration of a control unit of the sheet offset stacking apparatus 400.

  The CPU 111 has a ROM 110 inside. The ROM 110 stores a program corresponding to the control procedure described in the flowcharts shown in FIGS. The CPU 111 reads out and executes this program, and controls each unit. The CPU 111 has a RAM 120 built-in. The RAM 120 stores work data and input data denoted by reference numeral 121. The CPU 111 controls each unit based on the stored data.

  Various sensors such as an inlet sensor 403 and a sheet bundle discharge sensor 415 are connected to the input port of the CPU 111. Further, various motors such as a conveyance motor 431, an offset motor 432, a sheet bundle discharge motor 430, and various solenoids such as a pickup solenoid 433 and a clamp solenoid 434 are connected to the output port of the CPU 111. Based on the state of these sensors, the CPU 111 executes a program stored in the ROM 110 to control loads such as various motors and various solenoids connected to the output port.

  The CPU 111 includes a serial interface unit 130, and exchanges control data with the control unit 501 of the copying machine main body 500A shown in FIG. The CPU 111 controls each unit based on control data sent from the control unit 501 of the apparatus main body 500A via the serial interface unit 130.

  Next, the configuration diagram shown in FIGS. 1 to 14, the block diagram showing the configuration of the control unit of the sheet offset stacking device 400 shown in FIG. 15, and the explanation of the operation of the sheet offset stacking device 400 shown in FIGS. The operation of the sheet offset stacking apparatus 400 will be described based on the flowchart of FIG.

  When copying operation by the copying machine 500 is started, the CPU 111 of the sheet offset stacking apparatus 400 checks whether or not a sheet discharge signal is received from the control unit 501 of the apparatus body 500A of the copying machine 500 (S100). In the case of reception, the CPU 111 drives the pickup solenoid 433 shown in FIG. 12 to rotate the offset roller arm 406 to the position shown by the broken line in FIG. 4 and raises the offset roller 407 supported by the offset roller arm 406 ( S110).

  The CPU 111 drives the conveyance motor 431 shown in FIG. 12, and conveys the conveyance roller 405 shown in FIG. 2 and the offset roller 407 that rotates in synchronization with the conveyance roller 405 to the downstream side in the sheet conveyance direction (sheet discharge direction). It is rotated in the direction that can be performed (S120). As a result, the offset roller 407 rises and rotates to wait for a sheet to be fed.

  When the leading edge of the first sheet passes through the inlet sensor 403 shown in FIG. 2 (S130) and reaches the conveying roller 405, the sheet is conveyed by the conveying roller 405, and the apparatus main body 500A of the copier 500 shown in FIG. The delivery from the apparatus main body 500A is completed away from the internal sheet discharge unit 208 (S140).

  A conveyance roller 405 conveys the sheet to the post-processing tray 410. When the CPU 111 receives a sheet entry detection signal for detecting the trailing edge of the first sheet from the entrance sensor 403, the CPU 111 turns off the pickup solenoid 433 shown in FIG. 12 (S150). The offset roller 407 falls on the sheet surface by its own weight. In S120, the offset roller 407 has already been rotated in the same direction as the conveying roller 405, and conveys the sheet downstream to a predetermined position (S160).

  After that, when the sheet is conveyed to the predetermined stop position beyond the clamp claw 412, the CPU 111 stops the conveyance motor 431 and stops the rotation of the offset roller 407 (S 170), and stops conveying the sheet. Let When the rotation of the offset roller 407 stops, the CPU 111 operates the clamp solenoid 434 shown in FIG. 11 to open the clamp pawl 412 installed near the rear end stopper 411 as shown in FIG. 5 (S180). ). The CPU 111 rotates the transport motor 431 in the direction opposite to the sheet transport direction and reverses the offset roller 407. As shown in FIG. 6, the offset roller 407 reverses and conveys the sheet upstream, and as shown in FIG. 7, the upstream end (rear end) of the sheet abuts against the rear end stopper 411 (S190). . The CPU 111 stops the rotation.

  The amount of rotation of the offset roller 407 when the sheet is abutted against the trailing end stopper 411 is determined in consideration of the skew of the sheet that is generated when the sheet is fed from the copying machine 500, and the upstream of the sheet is stopped by conveying the sheet downstream. It is calculated by the CPU 111 so as to convey a distance slightly longer than the distance from the point of conveyance to the side (switchback conveyance) to the rear end stopper 411.

  The CPU 111 checks the size information of the sheet discharged from the copying machine 500 (S200), and the side edge alignment movement amount according to the size of the discharged sheet, that is, the sheet of the sheet discharged onto the post-processing tray 410. A moving distance necessary to press the side end along the discharge direction against the side end alignment wall 416 is calculated (S210). The offset roller 407 is offset to the side end alignment wall 416 by the rotation of the offset motor 432 and the pinion 423 and the movement of the rack 424 shown in FIG. 13 (S220).

  The sheet in contact with the offset roller 407 moves together with the offset roller 407 toward the side end alignment wall 416 by the frictional force of the offset roller 407. As shown in FIG. 7, the offset roller 407 abuts the side end Pa of the sheet P against the side end alignment wall 416, and then moves and stops slightly while sliding on the sheet. Then, the offset roller 407 conveys the sheet slightly downstream to make contact with the trailing edge stopper 411 and corrects the trailing edge in order to correct the misalignment of the trailing edge of the sheet after the side edge alignment movement. Thereby, the alignment of the side edge and the rear edge of the first sheet is completed (S230).

  When the offset process is not selected (NO in S410), the CPU 111 operates the pickup solenoid 433 to raise the offset roller 407 and move it away from the sheet (S240). Then, the CPU 111 turns off the clamp solenoid 434 and closes the clamp claw 412. The clamp claw 412 presses and holds the aligned sheet on the side end alignment wall 416 (S250).

  As a result, the sheet discharged first is not carried for conveyance downstream of the subsequent sheet to be discharged next in the sheet conveyance direction. While being lifted, the offset roller 407 moves to the home position by the rotation of the offset motor 432 and the pinion 423 and the movement of the rack 424 (S260).

  Thereafter, the CPU 111 checks whether or not the sheet stacked on the processing tray 410 is a sheet corresponding to the last page of the copy original (S270). If the CPU 111 determines that the page is not the last page based on the information sent from the copying machine 500, the CPU 111 returns to S100 and receives the sheet discharge signal sent from the copying machine 500 next, and the sheet of the last page is processed in the processing tray 410. The above flow is repeated until it is loaded on. Accordingly, the CPU 111 of the sheet offset stacking apparatus 400 grasps the size of the sheet every time the sheet is discharged from the copying machine 500, calculates the side edge alignment movement amount suitable for the sheet, and calculates the offset roller 407. Thus, the sheet is moved by the moving amount to align with the side end alignment wall 416.

  If the CPU 111 determines that the sheet is the last page, a sheet bundle corresponding to the copy document is formed on the processing tray 410, and thus checks whether or not the stapling process is selected (S280). If it is selected, the stapler unit 420 is driven to execute the stapling process (S290).

  After the stapling process is completed or when the stapling process is not selected, the CPU 111 clamps the sheet bundle discharging member 413 by rotating the sheet bundle discharging motor 430 and the pinion 435 and moving the rack 436. After grabbing with the claw 412 and moving toward the stack tray 421 (S300), the clamp solenoid 434 is driven to open the clamp claw 412, and the sheet bundle is discharged to the stack tray 421. Then, the stack tray 421 is lowered according to the thickness of the sheet bundle (S310). The sheet bundle discharge member 413 returns to the home position (S320), and the transport motor 431 stops rotating and stops the rotation of the transport roller 405 and the offset roller 407 (S330). Then, the pickup solenoid 433 is turned off and the offset roller 407 is lowered (S340). Thereby, a series of processes of the sheet offset stacking apparatus 400 is completed.

  If the offset process is selected in S410 (YES in S410), the CPU 111 stops the transport motor 431 and stops the rotation of the offset roller 407 (S420). The CPU 111 calculates the offset movement amount of the offset roller 407 (S430), and offset-moves the offset roller 407 by the calculated distance (S440). The CPU 111 turns off the clamp solenoid 434, closes the clamp claw 412, and presses and holds the sheet (S450). Thereafter, the offset roller 407 is lifted by the pickup solenoid 433 (S460) and then moved to the home position by the offset motor 432 (S470).

  The CPU 111 moves the sheet bundle discharge member 413 toward the stack tray 421 while the sheet bundle is gripped by the clamp claws 412 by the rotation of the sheet bundle discharge motor 430 and the pinion 435 and the movement of the rack 436 (S480). Then, the CPU 111 drives the clamp solenoid 434 to open the clamp pawl 412 and discharge the sheet bundle to the stack tray 421. Then, the stack tray 421 is lowered according to the thickness of the sheet bundle (S490).

  The CPU 111 returns the sheet bundle discharge member 413 to the home position (S500), and turns off the pickup solenoid 433 (S510). The offset roller 407 is lowered by its own weight.

  Thereafter, the CPU 111 checks whether or not the sheet stored on the post-processing tray 410 is a sheet corresponding to the last page of the copy original (S520). If the CPU 111 determines that the page is not the final page based on the information sent from the copying machine 500, the CPU 111 returns to S100 and receives the next sheet discharge signal sent from the copying machine 500, and the sheet on the last page is the post-processing tray. The above-described flow is repeated until it is accommodated in 410.

  Next, a method of calculating the offset movement amount from the side end alignment wall 416 will be described based on the flowchart of FIG.

  When the offset mode is selected by the user, the CPU 111 generates an offset movement amount calculation signal inside (S530). In the case of the first sort (S540), the distance from the side end alignment wall 416 that is the offset movement amount is 0 (S550), and the CPU 111 stores the calculated value in the RAM 120 (S560). The same calculated value is stored in the RAM 120 during the first sort.

  In the case of not the first sort (S540) but the second sort (S570), the CPU 111 sets the distance from the side end alignment wall 416, which is an offset movement amount, to a set value (for example, set in the RAM 120). 10) is multiplied by 1 (S580). The CPU 111 checks whether or not the calculated value is less than or equal to the maximum movement distance (S590), and stores the calculated value in the RAM 120 inside the CPU 111 (S560). The same calculated value is stored during the second sort.

  In the case of the n-th sort (S600), the CPU multiplies the distance from the side end alignment wall 416, which is the offset movement amount, by a setting value (for example, 10 mm) set in the RAM 120 by (n-1). (S610). The CPU 111 checks whether or not the calculated value is less than or equal to the maximum movement distance (S620), and stores the calculated value in the RAM 120 inside the CPU 111 (S560). The same calculated value is stored during the nth sort.

  In this way, the CPU 111 calculates the amount of offset movement that moves from the side end alignment wall 416 in the second, third,..., Nth sort.

  Further, although the set value that is the basic count of the offset movement distance set in the RAM 120 is described as a fixed value, the set value may be arbitrarily changed according to the paper size and the number of copies.

  Further, if the user can arbitrarily set the set value by using, for example, the operation panel 502 (see FIG. 1) which is an offset position setting means provided in the copying machine 500, the sheet offset stacking apparatus comprising a microcomputer system is provided. The CPU 111 of 400 can store the set value of the user input in the RAM 120 in the CPU 111 of the sheet offset stacking apparatus 400 by using serial communication with the control unit 501 of the copier 500. As a result, the amount of offset movement can be easily changed. When either one of the CPU 111 and the control unit 501 is incorporated in the other, it is not necessary to perform serial communication. Further, the operation panel may be provided in the sheet offset stacking apparatus 400 and the set value may be directly input to the CPU 111.

  The sheet offset stacking apparatus 400 described above has a function of moving a sheet to the downstream side and the upstream side in the sheet conveyance direction, and moves the sheet to the side edge alignment wall 416 or an offset position (a direction intersecting the sheet conveyance direction). An offset roller 407 having a function of moving the sheet to the downstream side and the upstream side in the sheet conveying direction, and a side edge alignment wall. The function may be distributed to 416 and the sheet orthogonal direction moving means having the function of moving to the offset position.

  The sheet offset stacking apparatus 400 stores a program corresponding to the control procedure shown in the flowcharts of FIGS. 16 to 18 on the ROM 110, and the CPU 111 reads the program to perform control. The same effect can be obtained even if the processing is performed by hardware.

1 is a schematic front view of a copying machine including a sheet offset stacking apparatus according to the present invention in an apparatus main body. It is an expanded sectional view of the sheet offset stacking apparatus of the present invention shown in FIG. FIG. 10 is a diagram illustrating a state where an offset roller of the sheet offset stacking apparatus is lowered onto the sheet and conveys the sheet downstream. FIG. 6 is a perspective view of a sheet offset stacking apparatus when an offset roller is lowered onto a sheet and conveys a sheet to the downstream side. FIG. 6 is a perspective view of a sheet offset stacking apparatus when an offset roller is transporting a sheet upstream. FIG. 10 is a perspective view of the sheet offset stacking device when the offset roller abuts the trailing end of the sheet against the trailing end stopper. FIG. 6 is a perspective view of a sheet offset stacking apparatus when an offset roller abuts a side edge of a sheet against a positioning wall. FIG. 6 is a perspective view of a sheet offset stacking device when an offset roller is separated from a sheet. FIG. 5 is a perspective view of a sheet offset stacking apparatus when a sheet is clamped by a clamp member and an offset roller returns to a position shown in FIG. 4. FIG. 6 is a perspective view of a sheet offset stacking apparatus when binding a sheet bundle by a stapler unit. It is an explanatory view of a drive mechanism of an offset roller, a conveyance roller, a sheet bundle discharge member, and a clamp claw. It is a top view of a sheet offset stacking apparatus. FIG. 6 is a plan view for explaining the operation of the sheet offset stacking apparatus when sheets are offset and stacked. FIG. 10 is a diagram for explaining an operation of discharging a sheet bundle to a stack tray by a sheet bundle discharge member. It is a block diagram showing a configuration of a control unit of the sheet offset stacking apparatus. 6 is a flowchart for explaining the operation of the sheet offset stacking apparatus. FIG. 17 is a flowchart for explaining an offset operation, following FIG. 16. It is a flowchart for operation | movement description which calculates offset movement amount. It is a schematic front view of the conventional sheet aligning apparatus.

Explanation of symbols

P sheet Pa sheet side edge Pb sheet upstream edge 100 reader unit 111 CPU
200 Printer 202 Photosensitive drum (image forming means)
300 Automatic document feeder (aka “ADF”)
400 Sheet offset stacking device 406 Offset roller arm 407 Offset roller (sheet conveying means)
410 Post-processing tray (sheet stacking means)
411 Rear end stopper (Upstream end receiving means)
412 Clamp claw (sheet moving means, sheet holding means)
413 Sheet bundle discharging member (sheet moving means, sheet holding means)
416 Side end alignment wall (side end alignment means)
420 Stapler unit 421 Stack tray 500 Copying machine (image forming apparatus)
500A Copier (image forming apparatus) main body 501 Control unit 502 Operation panel (offset position setting means)

Claims (7)

A sheet stacking means for stacking discharged sheets;
Sheet conveying means for moving the sheets stacked on the sheet stacking means to a plurality of offset positions in a direction intersecting the sheet discharge direction;
Sheet moving means for moving the sheet moved by the sheet conveying means to the downstream side in the sheet discharge direction of the sheet stacking means;
A sheet offset stacking apparatus comprising: Side end aligning means for receiving a side end portion along the sheet discharge direction of the sheet moved in the intersecting direction by the sheet conveying means,
The sheet moving means moves the sheet from the side end aligning means to any one of the offset positions after the sheet is once brought into contact with the side end aligning means. The sheet offset stacking apparatus according to Item 1. An upstream end receiving means disposed on the upstream side in the discharge direction of the sheet and receiving an upstream end of the sheet;
The sheet conveying means waits above the sheet stacking means when the sheet is discharged, and contacts the upper surface of the sheet when the sheet is discharged to the sheet stacking means. The sheet offset stacking apparatus according to claim 1, wherein the sheet offset stacking apparatus is capable of being conveyed to an upstream side in a sheet discharging direction and contacting the upstream end receiving unit.   The sheet offset stacking apparatus according to claim 1, wherein the sheet moving unit is also used as a sheet holding unit configured to hold a sheet stacked on the sheet stacking unit.   The sheet offset stacking apparatus according to claim 1, further comprising an offset position setting unit configured to set the plurality of offset positions by an external operation. Image forming means for forming an image on a sheet;
A sheet stacking unit on which the sheet on which an image is formed by the image forming unit is discharged and stacked;
Sheet conveying means for moving the sheets stacked on the sheet stacking means to a plurality of offset positions in a direction intersecting the sheet discharge direction;
Sheet moving means for moving the sheet moved by the sheet conveying means to the downstream side in the sheet discharge direction of the sheet stacking means;
An image forming apparatus comprising: Image forming means for forming an image on a sheet;
A sheet offset stacking apparatus for offset stacking sheets on which images are formed by the image forming unit,
6. The image forming apparatus according to claim 1, wherein the sheet offset stacking apparatus is the sheet offset stacking apparatus according to claim 1.

Images