JP4748577B2 - Sheet processing apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a sheet processing apparatus that aligns side edges of a sheet along a sheet conveyance direction, and an image forming apparatus including the sheet processing apparatus.

  2. Description of the Related Art Conventionally, an image forming apparatus that forms an image on a sheet may include a sheet processing apparatus that performs processing on a sheet on which an image is formed by the main body of the image forming apparatus. The sheet processing apparatus includes an apparatus that aligns (aligns) side edges along the sheet conveyance direction (see Patent Document 1). Note that aligning the side edges of the sheet is called side edge alignment. Further, when performing side edge alignment of sheets having the same width, the width alignment is performed to align the sheet width.

  For example, as shown in FIG. 6, the sheet processing apparatus described in Patent Document 1 moves in a direction (width direction) intersecting the sheet conveyance direction while keeping the offset roller 407 that conveys the sheet in contact with the sheet. Let Then, the sheet moves in the width direction together with the offset roller 407, and the side end is brought into contact with the side end positioning wall 416. As a result, the sheets are aligned at the side edges.

  However, the offset roller causes the sheet to contact the side edge positioning wall 416 when the sheet has been conveyed away from the side edge positioning wall 416 from a predetermined position or when there is an error in the sheet width size. I can't. For this reason, the distance by which the offset roller moves the sheet in the width direction is set to a distance obtained by adding the position error of the conveyed sheet and the sheet width size error to the original movement distance. That is, the offset roller 407 is set to slide on the sheet after the side edge of the sheet comes into contact with the side edge positioning wall 416.

JP 2005-132611 A

  However, in the conventional sheet processing apparatus, the sheet is brought into contact with the side end positioning wall at a stroke by one movement of the offset roller. For this reason, the following problem has arisen.

  (1) In the conventional sheet processing apparatus, when the sheet is conveyed to a position close to the side end positioning wall, after the sheet is brought into contact with the side end positioning wall, the offset roller moves excessively on the sheet. It will be. For this reason, a loop as indicated by symbol D in FIG. 14 may be formed at the side end portion of the sheet in contact with the side end positioning wall, for example, depending on the friction coefficient between the sheet and the offset roller. This loop is released when the offset roller moves away from the sheet. When the loop is released, the sheet moves away from the side end positioning wall due to the force of releasing the loop, and the sheet is misaligned in the sheet width direction (side end misalignment).

  (2) Since the conventional sheet processing apparatus is moved in the width direction at a stroke by one movement, the sheet may slide on the sheet before contacting the side end positioning wall. In this case, when the sheet is conveyed to a position away from the side end positioning wall, the offset roller cannot bring the sheet into contact with the side end positioning wall. As a result, the sheet processing apparatus causes alignment failure in the sheet width direction (side edge alignment failure).

  In addition, the image forming apparatus provided with the sheet processing apparatus having the above problems in the apparatus main body has a problem that it is difficult for the user to handle the sheet because the user needs to realign the sheets.

  Further, for example, when stapling a sheet bundle whose side ends are aligned, the stapling process is performed in a state where the side ends are not aligned correctly, so that the binding quality of the sheet bundle is significantly reduced.

  An object of the present invention is to provide a sheet processing apparatus in which the alignment accuracy of the side edges of the sheet is improved.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that includes a sheet processing apparatus that improves the alignment accuracy of the side edges of sheets, and that eliminates the need for the user to perform sheet alignment again and is easy for the user to handle.

The sheet processing apparatus according to the present invention includes a stacking unit on which a sheet transported in a predetermined transport direction is stacked , and moves in contact with an upper surface of the sheet stacked on the stacking unit, thereby moving the sheet in the predetermined transport direction. It includes a moving means for moving in a direction intersecting, and a side end positioning means for receiving the side edge of the sheet is moved in the intersecting direction by the moving means relative to said mounting means includes a plurality of A sheet of a size can be stacked, and the moving means contacts the upper surface of the sheet stacked on the stacking means , and then positions the side edge of the sheet according to the sheet size of the sheet. run the first operation of moving the movement amount the direction crossing for moving up means, once separated from the sheet after the first operation, then, from the spaced position of the seat Further performs the second operation of moving in a direction the cross and abut again to the surface, is characterized in that.

  An image forming apparatus according to the present invention includes: an image forming unit that forms an image on a sheet; and a sheet processing device that processes a sheet on which an image has been formed by the image forming unit. It is a device.

The sheet processing apparatus of the present invention, the moving means, the sheet is moved to the side end positioning means, so as to separate the sheet or et once. For this reason, the sheet processing apparatus according to the present invention releases the sheet at least once when a loop is about to be formed on the sheet that is in contact with the side edge positioning means or during the formation. It does not form a loop. Even if a loop is formed, the loop can be made smaller. Therefore, the sheet processing apparatus of the present invention can reliably perform alignment (side edge alignment) in the sheet width direction.

  Further, the sheet processing apparatus according to the present invention provides a moving means for the sheet because the moving means is separated from the sheet at least once when the moving means is about to slide on the sheet before the sheet abuts the side end positioning wall. Can be prevented from slipping. Therefore, the sheet processing apparatus of the present invention can reliably align the sheet in the sheet width direction (side end alignment) by reliably bringing the sheet into contact with the side end positioning wall.

  The image forming apparatus according to the present invention includes a sheet processing apparatus that improves the alignment accuracy of the side edges of the sheet, so that it is not necessary for the user to perform sheet alignment again, and the user can easily handle the sheet.

  Further, for example, when the sheet processing apparatus can bind the sheet bundle by aligning the side edges of the sheets, the binding quality of the sheet bundle can be improved.

  Hereinafter, a sheet processing apparatus according to an embodiment of the present invention and an image forming apparatus including the sheet processing apparatus will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view of an image forming apparatus including a sheet processing apparatus according to an embodiment of the present invention along the sheet conveyance direction.

  The image forming apparatus 500 includes a reader unit (image input apparatus) 120 that reads an original image and converts it into image data on the upper part of the image forming apparatus main body 500A. An automatic document feeder (ADF) 300 is provided above the reader unit 120. The sheet processing apparatus 400 performs a side edge alignment process for aligning the side edges of the sheets on which an image is formed and discharged by the image forming apparatus main body 500A, and a stapling process for binding the sheet bundle. Note that when performing side edge alignment of sheets having the same width, the sheet width alignment is performed simultaneously. Further, the sheet processing apparatus 400 may be configured to perform only the sheet side edge alignment processing.

  A rail member 440 is provided below the sheet processing apparatus 400. The sheet processing apparatus 400 is pulled out obliquely with respect to the conveying direction by the rail member 440 so that the staples of the stapler unit 420 (see FIG. 4) can be replenished.

  A reader unit (image reading apparatus) 120 converts a document into image data. For example, the printer unit 200 as image forming means is a portion that forms image data as a toner image on the photosensitive drum 202 by a print command, transfers the toner image to a sheet, and visualizes the image.

  The image forming apparatus 500 having such a configuration reads the originals (not shown) conveyed one by one from the automatic document feeder 300 onto the platen glass 102 of the reader unit by the reader unit 120 and copies the originals on the sheet. It is like that.

  When the document is conveyed to a predetermined position on the platen glass 102, the lamp 103 of the reader unit 120 is turned on, the scanner unit 104 is moved, and the lamp 103 is moved while irradiating the document. Reflected light from the document is input to the CCD image sensor unit 109 through the mirrors 105, 106, 107 and the lens 108, and electrical processing such as photoelectric conversion is performed in the CCD image sensor unit 109, and normal digital processing is performed. The

  The image signal that has been subjected to the electrical processing is converted into a modulated optical signal by the exposure control unit 201 of the printer unit 200 and irradiates the photosensitive drum 202. A latent image is formed on the photosensitive drum 202 by the irradiation light. This latent image is developed by the developing device 203 and formed on the photosensitive drum 202 as a toner image.

  The sheet S sent out from the sheet cassettes 204 and 205 is timed with the leading edge of the toner image, and the toner image is transferred by the transfer unit 206. The toner image transferred to the sheet S is fixed to the sheet by the fixing unit 207. Thereafter, the sheet S is discharged from the paper discharge unit 208.

  After the image formation, the sheet S discharged from the paper discharge unit 208 is conveyed to the sheet processing apparatus 400, and side edge alignment processing and stapling processing are performed according to an operation mode designated in advance by the sheet processing apparatus 400. . Then, the sheets are stacked on the stack tray 421.

  The image forming apparatus according to the present exemplary embodiment transmits a function of forming image information on a sheet based on image information transmitted from the outside and the image information read by the reader unit 120 to another image forming apparatus. And a function to perform. Accordingly, the image forming apparatus of the present embodiment does not necessarily require the automatic document feeder 300.

  Next, the sheet processing apparatus 400 will be described. The sheet processing apparatus is operated under the control of the CPU 100. The CPU 100 exchanges signals necessary for control with a control unit in the apparatus main body 500A of the image forming apparatus.

  The sheet processing apparatus 400 performs side edge alignment processing for aligning the side edges of sheets discharged after the image is formed by the image forming apparatus main body 500A, sorting processing for sorting sheets, and stapling processing for binding sheet bundles. ing. Note that the side edge of the sheet is an edge of the sheet along the sheet conveyance direction. When performing side edge alignment of sheets having the same width, sheet width alignment is performed simultaneously. Further, the sheet processing apparatus 400 may be configured to perform only the sheet side edge alignment processing.

  As shown in FIG. 2, the sheet processing apparatus 400 includes, for example, a processing tray 410 serving as a stacking unit on which sheets S sequentially discharged from the image forming apparatus main body 500A are stacked, and a sheet bundle processed on the processing tray 410. A stack tray 421 and the like to be finally loaded are provided. The sheet processing apparatus 400 stacks a number of sheets corresponding to the number of documents on the processing tray 410 in a bundle, and discharges and stacks the sheets on the stack tray 421 for each sheet bundle.

  In FIG. 2, a sheet receiving unit 401 is a part that receives the sheet S discharged from the image forming apparatus main body 500A. The sheet S discharged to the sheet receiving unit 401 is detected by the entrance sensor 403 and then conveyed by the conveying roller 405 and the offset roller 407, and then discharged onto the processing tray 410 shown in FIG. Note that the sheets S stacked on the processing tray 410 are detected by the sheet bundle discharge sensor 415 shown in FIG.

  The offset roller 407 is held up and down by an offset roller arm 406 that can move up and down around a shaft 406a shown in FIGS. The offset roller 407 moves upward via the offset roller arm 406 when the sheet S is discharged to the processing tray 410. As a result, the sheet S is discharged onto the processing tray 410 without being obstructed by the offset roller 407.

  The offset roller arm 406 is moved up and down by a pickup solenoid 433 with a shaft 406a as a fulcrum. That is, the offset roller 407 is moved up and down by the on / off operation of the pickup solenoid 433.

  As shown in FIG. 5, the offset roller 407 is rotated via belts 431a and 431b by a conveying motor 431 that rotates the conveying roller 405. When the transport motor 431 rotates, the offset roller 407 rotates (reverses) in the transport direction or in the direction opposite to the transport direction by an amount corresponding to the rotation amount of the transport motor 431.

  Accordingly, after the entrance sensor 403 detects the leading edge of the sheet, the pickup solenoid 433 is turned off when a predetermined time set in advance according to the sheet size elapses. Then, the offset roller 407 descends onto the sheet by its own weight, and then rotates in the sheet conveyance direction for a predetermined time to convey the sheet downstream.

  The offset roller 407 reverses for a predetermined time when a predetermined time elapses. The reversely rotating offset roller 407 abuts the trailing end (upstream end) of the sheet against an upstream end positioning unit, for example, a sheet trailing end stopper 411 erected at the upstream end of the processing tray 410 in the conveyance direction. Align in the transport direction.

  In FIG. 4, for example, a side end positioning wall 416 that is a side end positioning unit is a member that regulates the position of an end (side end) in a direction (hereinafter referred to as a width direction) that intersects the sheet conveyance direction of the sheet. The stapler unit 420 is disposed in the vicinity of the side end positioning wall 416 of the processing tray 410 so as to bind the sheet bundle formed on the processing tray 410. The offset roller 407 moves in the width direction via the pinion 423 and the rack 424 by driving of the offset motor 432, and comes close to the side end positioning wall 416. The offset roller 407 and the offset motor 432 are examples of moving means.

  The offset roller 407 rotates in the reverse direction and moves the sheet S having the upstream end (rear end) in the sheet conveying direction against the sheet rear end stopper 411 as it is, and moves in the sheet width direction (arrow K direction). Then, the sheet is moved following the offset roller 407 by the frictional force of the offset roller 407, and the side end is brought into contact with the side end positioning wall 416. As a result, the sheet is positioned in the width direction (side edge alignment).

  The sheet S is guided by the guide surface 700d of the sheet pressing member 700 shown in FIGS. 4 and 14 immediately before coming into contact with the side end positioning wall 416 and enters between the pressing piece 700b and the processing tray 410, and the side end positioning wall. 416 abuts. The guide surface 700d is an inclined surface that approaches the processing tray 410 as it approaches the side end positioning wall 416.

  As shown in FIGS. 4 and 14, the sheet pressing member 700 is rotatably provided on the shaft 406 a and presses the sheet by its own weight. The sheet pressing member 700 is not always necessary.

The offset roller 407 (FIG. 6) is illustrated at a distance (X in FIG. 9A) from the position of the side edge of the sheet S conveyed from the image forming apparatus 500 into the sheet processing apparatus 400 to the side edge positioning wall 416. The side edge of the sheet is aligned by moving the distance Y of 9 (c) and the distance Z of FIG. 9 (d). Offset rollers are at a distance X, the position of the distance Y, the distance to stop at the position of Z, are brought into contact spaced against the seat back in place. That is, the offset roller performs the first offset movement to the position of the distance X, the second offset movement from the position of the distance X to the position of the distance Y, and the third time from the position of the distance Y to the position of the distance Z. Therefore the offset movement, and performs the side edge alignment of the sheet. Although the offset roller 407 is stopped three times, the number of times is not limited to three and may be any number. It may be only once.

  The offset roller 407 moves the sheet S conveyed from the image forming apparatus 500 into the sheet processing apparatus 400 by a distance (FIG. 9A) by the first offset movement (alignment operation in the width direction) (FIG. 6C). X). At this time, if the sheet is a sheet conveyed without being skewed from the image forming apparatus 500, the sheet abuts against the side end positioning wall 416 without causing a loop (FIG. 9B). When the sheet is a sheet that is conveyed obliquely in a direction approaching the side end positioning wall 416 from the image forming apparatus 500, the sheet is positioned closer to the side end positioning wall 416 by the amount of the skew. Therefore, a loop (D in FIG. 14) is formed at the side end of the sheet S. Note that the distance X is set to a distance at which side edge alignment can be performed without forming a loop on the sheet conveyed without skew, and therefore, in the case of a skewed sheet, the minimum amount of the skew is equal to the sheet. The distance is set to form a limit loop. Therefore, the loop generated in the skew sheet is a minimum loop corresponding to the skew.

  Subsequently, when the pickup solenoid 433 is turned on while the offset roller 407 is stopped at the position of the distance X, the offset roller 407 is separated from the sheet S ((a) in FIG. 7), and is formed by the first offset movement. The opened loop is opened (in the direction of arrow H in FIG. 14). At this time, the sheet pressing member 700 presses the sheet S with its own weight.

  After that, when the pickup solenoid 433 is turned off, the offset roller 407 comes into contact again with the position separated from the sheet S (FIGS. 7A and 9B) (FIG. 7B).

  When the offset motor 432 rotates again to make the offset roller 407 perform the second offset movement, the offset roller 407 approaches the sheet positioning wall 416 (FIGS. 7C and 9C). At this time, the sheet movement amount Y of the offset roller 407 is set so that the side edge of the sheet S is conveyed to the side edge positioning wall 416 by about 3 mm (to the extent that a loop cannot be formed at the sheet side edge). .

  When the second offset movement by the offset roller 407 causes a misalignment of the sheet S side end due to the first offset movement, the misalignment can be absorbed.

  In addition, since the feeding amount in the second offset movement of the offset roller 407 is set to a minimum, loop formation on the sheet S side end can be suppressed.

  After that, by continuing the second offset movement and the third offset movement of the offset roller 407 (FIG. 9D), the side edge of the sheet S is reliably brought into contact with the side edge positioning wall 416. At the same time, the skew in the sheet width direction is corrected.

  Further, the sheet S conveyed from the image forming apparatus 500 into the sheet processing apparatus 400 may be skewed and conveyed to a position away from the side end positioning wall 416. Further, in the first offset movement of the offset roller 407, if the sliding resistance of the sheet with respect to the processing tray 410 or the sliding resistance between the sheets is large, the offset roller slips on the sheet and the sheet is positioned on the side edge positioning wall 416. May not be able to move to

  Even in such a case, the offset roller 407 performs the retry alignment that repeats further offset movement after the third time (FIGS. 9C and 9D), thereby positioning the side edge of the sheet S to the side edge. The sheet can be reliably aligned by abutting against the wall 416. In addition, the skew of the sheet can be corrected.

  The description of the sheet post-processing operation will be continued.

  The sheet discharged onto the processing tray 410 is conveyed to the stack tray 421 (see FIGS. 1 to 3) by an offset roller 407 that rotates in the sheet conveying direction as shown in FIG. Thereafter, as shown in FIG. 6B, the sheet is returned to the sheet trailing edge stopper 411 by the reverse rotation of the offset roller 407, and the trailing edge (upstream edge) is abutted against the sheet trailing edge stopper 411. Be matched.

  Then, as shown in FIG. 6C, the offset roller 407 moves closer to the side end positioning wall 416 along the shaft 406a while being in contact with the upper surface of the sheet S, and the width direction side of the sheet S is reached. The first alignment in the width direction in which the end Sa is pressed against the side end positioning wall 416 is performed. Thereafter, the offset roller 407 performs the second and subsequent alignments in the sheet width direction. Finally, the offset roller 407 performs side edge alignment of the sheet S.

  In FIG. 5, the clamp solenoid 434 rotates the sheet clamp member 412. The clamp solenoid 434 is turned on when the rotation is stopped after the offset roller 407 conveys the sheet and when the offset roller 407 moves in the sheet width direction, and rotates the sheet clamp member 412 upward via the lever 434a. It is supposed to be moved.

  When the alignment processing for the designated number of sheets is completed, the clamp solenoid 434 closes the sheet clamp member 412 and causes the sheet clamp member 412 to hold the sheet bundle.

  On the other hand, in FIG. 5, the sheet clamp member 412 holds the rear end portion of the aligned sheets S by the biasing force of a biasing member (not shown). After the alignment of the trailing edge of the sheet, as shown in FIG. 7A, after the offset roller 407 is lifted by the pickup solenoid 433, the sheet clamp member 412 moves the aligned sheet S to the position shown in FIG. Press (hold) from above as shown in (b). As a result, the sheet S previously discharged to the processing tray 410 is then held at a predetermined position without being influenced by the accompanying sheet S that is sequentially fed.

  In addition, the sheet clamp member 412 is in a position rotated upward so that the sheet S can be received while the offset roller 407 is reversed to align the trailing end of the sheet as shown in FIG. 6B. Is retained. Further, as shown in FIG. 6C, the sheet clamp member 412 is subjected to a load of movement of the sheet S even when the sheet S is moved in the width direction together with the offset roller 407 in order to align the side edges of the sheet. It is held in a position rotated upward so that it does not become.

  In FIG. 5, when the power of the sheet bundle discharge motor 430 is transmitted via the rack and the pinion, the sheet bundle discharge member 413 and the home position near the sheet trailing edge stopper 411 are discharged from the stack tray 421. It is designed to reciprocate between. The sheet bundle discharge member 413 is normally fixed at the home position by excitation of the sheet bundle discharge motor 430.

  5 and 10, the sheet bundle discharge member 413 holds the sheet clamp member 412 so as to be rotatable. The sheet bundle discharging member 413 moves the aligned sheet bundle or the aligned and bound sheet bundle bound by the stapler unit 420 (see FIG. 4) to the stack tray 421 while holding the sheet clamp member 412. To do.

  Thereafter, when the sheet bundle discharge member 413 reaches the leading end of the processing tray 410 that is the sheet discharge position indicated by the solid line in FIG. 10, the sheet clamp member 412 releases the holding of the sheet bundle SA on the stack tray 421. As a result, the sheet bundle SA is discharged to the stack tray 421.

  FIG. 11 is a block diagram illustrating a configuration of a control unit of the sheet processing apparatus 400. The CPU 100 has a ROM 110 therein, and programs and the like corresponding to control procedures shown in FIG. 12 and FIG. The CPU 100 controls each unit while reading this program. The CPU 100 may be integrated with a control unit 140 (see FIG. 1) provided in the image forming apparatus main body, and may be incorporated in either the sheet processing apparatus or the image forming apparatus main body.

  Further, the CPU 100 has a RAM 121 in which work data and input data are stored, and the CPU 100 performs control with reference to data stored in the RAM 121 based on the program. Furthermore, sensors such as an inlet sensor 403 and a sheet bundle discharge sensor 415 are connected to the input port of the CPU 100. Based on the state of each sensor, the CPU controls loads such as the conveyance motor 431, the offset motor 432, the sheet bundle discharge motor 430, the pickup solenoid 433, and the clamp solenoid 434 connected to the output port according to the above-described program. ing.

  The CPU 100 also includes a serial interface unit (I / O) 130. The CPU 100 exchanges control data with the control unit 140 of the apparatus main body 500A of the image forming apparatus via the serial interface unit (I / O) 130. Further, the CPU 100 controls each part of the sheet processing apparatus based on control data sent from the control part 140 of the image forming apparatus main body 500A via the serial interface part (I / O) 130. Yes.

Incidentally, the image forming apparatus main body 500A grasps the size of the sheet discharged from the sheet discharging portion 208. For this reason, the CPU 100 of the sheet processing apparatus 400 can grasp the size of the sheets stacked on the processing tray 410 by serial communication with the control unit 140 of the image forming apparatus main body 500A.

  The CPU 100 of the sheet processing apparatus 400 can grasp the size and control the offset motor 432 each time the sheet S is discharged from the image forming apparatus main body 500A. For this reason, the CPU 100 of the sheet processing apparatus 400 can control the offset motor 432 to move the offset roller 407 away from the sheet to a position corresponding to the contact position of the offset roller 407 with respect to the sheet. . As a result, the offset roller 407 contacts the sheet when moved by an amount corresponding to the width of the sheet discharged on the processing tray 410 and moves the sheet S by moving by a preset sheet width. It can abut against the end positioning wall 416. Further, the CPU 100 controls the pickup solenoid 433 to separate the offset roller 407 from the sheet. Thereafter, the CPU 100 brings the offset roller 407 into contact with the sheet again, and moves a predetermined fixed amount toward the side end positioning wall 416. The CPU 100 can repeat these operations to bring the side end of the sheet S into contact with the side end positioning wall 416 and align it. Further, skew in the width direction of the sheet can be corrected.

  Next, the sheet processing operation of the sheet processing apparatus 400 configured as described above is shown in the configuration diagrams shown in FIGS. 1 to 10 and 14, the control block diagram shown in FIG. 11, and FIGS. 12 and 13. This will be described based on the flowchart. In the following description of the flowchart, it is assumed that the sheet is conveyed based on the center.

  When the image forming operation is started in the image forming apparatus main body 500A, the CPU 100 (see FIG. 11) of the sheet processing apparatus 400 checks whether a sheet discharge signal is received from the image forming apparatus main body 500A (S100). At this time, the offset roller 407 stands by at a center position that matches the center reference of the conveyed sheet. This position is called a standby position. A position where the offset roller 407 contacts the sheet is referred to as a contact position.

  The standby position and the contact position may be the same or different, but here the sheet is conveyed on the basis of the center, so the standby position and the contact position are the same.

  Here, when the sheet discharge signal is received (YES in S100), the CPU 100 turns on the pickup solenoid 433 (see FIG. 4) (S110). The pickup solenoid 433 pulls up the offset roller arm 406 having the offset roller 407. Thereafter, the CPU 100 rotates the offset motor 432 (see FIG. 4) to move the offset roller 407 to the contact position (FIG. 6A) corresponding to the sheet size.

  Next, the CPU 100 rotates the transport motor 431 (see FIG. 4) (S120). The conveyance motor 431 rotates so that the conveyance roller 405 (see FIGS. 2 and 4) installed in the middle of the path can convey the sheet in the same direction as the sheet discharge direction of the image forming apparatus main body 500A. Here, the leading edge of the first sheet passes through the inlet sensor 403 (see FIG. 2) and turns on the inlet sensor 403 (YES in S130). The first sheet reaches the conveyance roller 405, receives conveyance force from the conveyance roller 405, leaves the sheet discharge unit 208 (see FIG. 1) of the image forming apparatus main body 500A (YES in S140), and passes to the sheet processing apparatus 400. It is.

  Next, the CPU 100 conveys the sheet to the processing tray 410 by the conveying roller 405 and turns off the pickup solenoid 433 before the sheet is completely removed from the conveying roller 405 (S150), and sets the offset roller 407 under its own weight. Land on top. Thereafter, as shown in FIG. 6A, the CPU 100 controls the transport motor 431 to transport the sheet S to a predetermined position downstream in the sheet transport direction by the offset roller 407 (S160). When the sheet S is conveyed to a predetermined position on the downstream side in the sheet conveying direction (YES in S160), the CPU 100 stops the rotation of the conveying motor 431 (S170) and stops conveying the sheet S.

  Next, when the rotation of the offset roller 407 stops, the CPU 100 turns on the clamp solenoid 434 (S180), and as shown in FIG. 6B, the sheet clamp installed near the sheet trailing edge stopper 411. Open member 412. Thereafter, the CPU 100 controls the rotation of the transport motor 431 in the direction opposite to the transport direction, and pulls back the sheet S from the predetermined position downstream in the sheet transport direction to the upstream side by the offset roller 407 (S190). The end is brought into contact with the sheet rear end stopper 411.

  Note that the rotation amount of the offset roller 407 when the trailing edge of the sheet abuts against the sheet trailing edge stopper 411 is set to a rotation amount that eliminates the skew of the sheet S that is generated when the sheet is fed from the image forming apparatus main body 500A. Has been. That is, the rotation amount of the offset roller 407 can convey the sheet slightly more than the distance from the switchback point where the conveyance of the sheet S to the downstream side in the sheet conveyance direction is stopped and returned to the upstream side to the sheet trailing edge stopper 411. Is set to

  Next, the CPU 100 checks the sheet size to be discharged based on the size information from the image forming apparatus main body 500A (S200), and according to the discharged sheet size, the sheet side edge is conveyed to the side edge positioning wall 416. The amount of movement is calculated (S210).

  Then, the CPU 100 controls the offset motor 432 (see FIG. 4), and the offset roller 407 is offset to the side end positioning wall 416 through the pinion 423 and the rack 424 as shown in FIG. (S220). When the offset roller 407 moves, the sheet S in contact with the offset roller 407 moves together with the offset roller 407 toward the side end positioning wall 416 by the frictional force of the offset roller 407.

  At this time, the sheet clamp member 412 is rotated upward as shown in FIG. 7A so as not to be a load of movement of the sheet S. Further, even if the sheet clamp member 412 is directed upward, it does not interfere with the offset roller 407 and the offset roller arm 406.

  Next, the offset roller 407 moves the sheet S by an amount that abuts against the side end positioning wall 416 to bring the side end portion of the sheet S into contact with the side end positioning wall 416 and performs the first offset movement (S220). .

  Next, the CPU 100 turns on the pickup solenoid 433 (S230) and pulls up the offset roller 407 supported by the offset roller arm 406. Then, the CPU 100 turns off the pickup solenoid 433 (S240), and causes the offset roller 407 to land on the sheet with its own weight.

  Next, the CPU 100 calculates the amount of movement of the offset roller 407 by which the sheet side edge is offset again to the side edge positioning wall 416 (S250). Then, the CPU 100 controls the offset motor 432 (refer to FIG. 4) to the offset roller 407 via the pinion 423 and the rack 424 toward the side end positioning wall 416 as shown in FIG. The second offset is moved (S260). When the offset roller 407 performs the second offset movement, the sheet S in contact with the offset roller 407 moves together with the offset roller 407 toward the side end positioning wall 416 by the frictional force of the offset roller 407.

  At this time, if the side edge of the sheet S is already in contact with the side edge positioning wall 416, the sheet S does not move, and only the offset roller 407 moves while slipping on the upper surface of the sheet S (S260). Further, the sheet clamp member 412 is rotated upward as shown in FIG. 7C so as not to be a load of movement of the sheet S.

  Thereafter, the CPU 100 repeats the second offset operation (S230 to S260) of the offset roller 407 a plurality of times.

  Thereby, even if the sliding resistance of the sheet S is large and the offset roller 407 slips on the sheet S, the offset roller 407 performs retry alignment so that the side edge of the sheet S is changed to the side edge. The positioning wall 416 can be reliably brought into contact.

  When the alignment of the first sheet S is completed in this way, the CPU 100 turns on the pickup solenoid 433 (see FIG. 4) (S270) and lifts the offset roller 407 as shown in FIG. 8A. Then, the CPU 100 and the clamp solenoid 434 (see FIG. 5) are turned off (S280).

  As a result, as shown in FIG. 8B, the sheet S is held by the sheet clamp member 412, and is prevented from being conveyed to the downstream side in the sheet conveying direction by the next discharged sheet.

  Next, the CPU 100 rotates the offset motor 432 and returns the lifted offset roller 407 to the home position which is the standby position described in the processing S100 ((b) and S290 in FIG. 8). .

  Then, the CPU 100 checks whether or not the sheet S accommodated on the processing tray 410 is the last sheet corresponding to the last page of the copy original (S300). If the CPU 100 determines that it is not the final sheet S based on the information sent from the image forming apparatus main body 500A (NO in S300), the CPU 100 returns to the processing S100 and the last sheet S is sent to the processing tray 410. Steps S100 to S300 are repeated until the above.

  Whenever the sheet S is sent from the image forming apparatus main body 500A, the CPU 100 of the sheet processing apparatus 400 grasps the width size of the sheet S and calculates the offset amount. Then, the CPU 100 can convey the sheet S in contact with the offset roller 407 by an offset amount suitable for each sheet size, and abut against the side end positioning wall 416 for alignment.

On the other hand, if the CPU 100 determines that the sheet is the final sheet (YES in S300), a sheet bundle corresponding to the copy document is formed on the processing tray 410, and therefore whether or not the stapling process is selected next. Is checked (S310). CPU100 is, (YES in S310) if the stapling process is selected, bind the sheet bundle by operating the stapler La unit 420 (S320).

  Next, when the stapling process is not selected (NO in S300), or when the stapling process is completed, the CPU 100 rotates the sheet bundle discharge motor 430 (see FIG. 5). The sheet bundle discharge motor 430 advances the sheet bundle discharge member 413 (see FIGS. 5 and 10) holding the sheet bundle with the sheet clamp member 412 toward the stack tray 421 to discharge and move the sheet bundle SA ( S330).

  The CPU 100 operates the clamp solenoid 434 to release the grip of the sheet bundle by the sheet clamp member 412 and discharge the sheet bundle to the stack tray 421 (S340). Then, the CPU 100 controls the sheet bundle discharge motor 430 to return the sheet bundle discharge member 413 to the home position (S350). Further, thereafter, the CPU 100 stops the transport motor 431 in order to stop the rotation of the transport roller 405 and the offset roller 407 (S360). The CPU 100 also turns off the pickup solenoid 433 (S370) and lowers the offset roller 407 by its own weight. As a result, the sheet processing apparatus ends a series of alignment processes.

  In the sheet processing apparatus of the present embodiment, the CPU performs control while the CPU reads the program written on the RAM (or ROM) shown in the flowcharts of FIGS. 12 and 13. The same effect can be obtained even if it is configured to perform.

  Further, since the sheet processing apparatus of the present embodiment assumes that the sheet is conveyed with the center reference, the standby position of the offset roller 407 is made to wait at the center position corresponding to the center reference of the conveyed sheet. . In the sheet processing apparatus according to the present embodiment, when the sheet is sent from the image forming apparatus main body with one side reference, the standby position of the offset roller is set at a certain distance from the one side reference position of the sheet regardless of the sheet size. To the position. Even in this case, the offset roller 407 is offset a plurality of times to perform side edge alignment of the sheet.

  Further, in the above-described contents, the offset movement after the second time is assumed to repeat the offset matching amount at the second offset roller 407. However, the offset matching amount of the offset roller after the second time is changed to the second time to perform the alignment. Of course.

  As described above, the sheet processing apparatus according to this embodiment is configured to position the side edge of the sheet after the upstream end of the sheet is brought into contact with the sheet trailing edge stopper 411 by the offset roller 407. However, when the above-described pressing member 710 is used, the offset roller 407 causes the side edge of the sheet to abut against the side edge positioning wall 416 to position the side edge of the sheet, and then the upstream edge of the sheet is used as the sheet trailing edge stopper You may make it contact | abut to 411. In this case, the same effect can be obtained.

  Since the image forming apparatus 500 of the present invention includes the sheet processing apparatus 400 that improves the alignment accuracy of the side edges of the sheets, it is possible to improve the sheet binding quality when stapling the sheet bundle. Further, even when the sheet is not subjected to the stapling process, the user does not need to realign the sheet, and the apparatus is easy to handle for the user.

1 is a cross-sectional view of an image forming apparatus including a sheet processing apparatus according to an embodiment of the present invention along a sheet conveying direction. FIG. 2 is a cross-sectional view along the sheet conveyance direction in the sheet processing apparatus of FIG. 1. It is a figure which shows a mode that a sheet | seat is discharged by the processing tray of the sheet processing apparatus of FIG. FIG. 2 is a schematic plan view of a drive mechanism portion of an offset roller and a conveyance roller of the sheet processing apparatus of FIG. 1. FIG. 2 is a schematic front view of a driving mechanism for an offset roller, a conveyance roller, a sheet bundle discharge member, and a sheet clamp member of the sheet processing apparatus of FIG. 1. FIG. 2 is a diagram for explaining the operation of an offset roller and the accompanying sheet movement in the sheet processing apparatus of FIG. 1. (A) It is a figure which the offset roller is conveying the sheet | seat downstream. FIG. 6B is a diagram illustrating that the offset roller conveys the sheet to a predetermined position on the downstream side and then conveys the sheet toward the sheet trailing edge stopper. (C) The offset roller conveys the sheet toward the side end positioning wall by the first offset movement. FIG. 2 is a diagram for explaining the operation of an offset roller and the accompanying sheet movement in the sheet processing apparatus of FIG. 1. (A) It is a figure of the state which left | separated from the sheet | seat after the offset roller butted the sheet | seat on the side end positioning wall. (B) It is a figure of the state in which the offset roller contacted the sheet again. (C) is a diagram in which the offset roller conveys the sheet toward the side end positioning wall by the second offset movement. FIG. 2 is a diagram for explaining the operation of an offset roller and the accompanying sheet movement in the sheet processing apparatus of FIG. 1. (A) It is a figure of the state which left | separated from the sheet | seat after the offset roller butted the sheet | seat at the side edge positioning wall by the 2nd offset movement. (B) It is a figure of the state which an offset roller returns to a standby position. FIG. 2 is a diagram for explaining the operation of an offset roller and the accompanying sheet movement in the sheet processing apparatus of FIG. 1. (A) It is a figure of the state in which the offset roller is waiting at a home position. (B) It is a figure of the state in which the offset roller is conveying the sheet | seat toward the side end positioning wall by the 1st offset movement. (C) It is a figure of the state which the offset roller is conveying the sheet | seat toward the side end positioning wall by the offset movement of the 2nd time. (D) It is a figure of the state which the offset roller is conveying toward the side end positioning wall by the 3rd offset movement. FIG. 8 is a diagram for explaining the operation of the sheet clamp member in the sheet processing apparatus of FIG. 1. 3 is a block diagram illustrating a configuration of a control unit of the sheet processing apparatus. FIG. 6 is a flowchart for explaining a part of the sheet processing operation of the sheet processing apparatus. It is a flowchart following FIG. FIG. 5 is a view corresponding to a view of FIG. 4 viewed from the left side, and is a view showing a relationship between an offset roller unit and a sheet pressing member.

Explanation of symbols

S sheet SA sheet bundle 100 CPU
200 Printer unit (image forming means)
300 Automatic Document Feeder 400 Sheet Processing Device (Sheet Processing Device)
401 Sheet receiving portion 406 Offset roller arm 407 Offset roller (moving means)
410 Processing tray (loading means)
411 Sheet rear end stopper (upstream side positioning means)
412 Sheet clamp member 416 Side end positioning wall (side end positioning means)
420 Stapler unit 432 Offset motor (moving means)
433 Pickup solenoid 500 Image forming apparatus 500A Image forming apparatus main body

Claims (4)

Stacking means for stacking sheets conveyed in a predetermined conveying direction ;
Moving means for moving the sheet in a direction intersecting the predetermined conveying direction by moving in contact with the upper surface of the sheet stacked on the stacking means;
In the sheet processing apparatus comprising: a side end positioning unit that receives a side end of the sheet moved in the intersecting direction by the moving unit;
The stacking means can stack a plurality of sizes of sheets,
The moving means contacts the upper surface of the sheets stacked on the stacking means , and then, according to the sheet size of the sheets, the moving amount for moving the side edges of the sheets to the side edge positioning means run the first operation of moving in a direction intersecting, once separated from the sheet, then moved from a position spaced the intersecting direction to abut again on the upper surface of the sheet after the first operation Further perform the second action,
A sheet processing apparatus. An upstream end positioning unit that is provided upstream of the stacking unit in the predetermined conveyance direction and receives an upstream end of a sheet ;
It said moving means are possible conveying the sheets stacked on the stacking unit on the upstream side of said predetermined conveying direction, wherein the upstream end of the sheet to convey the sheet stacked on said stacking means to said upstream Positioning by contacting the upstream end positioning means,
The sheet processing apparatus according to claim 1. The moving means has a roller capable of forward and reverse rotation,
The roller is capable of transporting the sheets stacked on the stacking means to the upstream side and the downstream side in the predetermined transport direction.
The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is a sheet processing apparatus. Image forming means for forming an image on a sheet;
A sheet processing apparatus for processing a sheet on which an image is formed by the image forming unit,
The sheet processing apparatus is the sheet processing apparatus according to any one of claims 1 to 3.
An image forming apparatus.

Images