JP2011241025A - Sheet processing apparatus and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet processing apparatus for reliably performing processing for breaking a bent part of the flux of sheets, and to provide an image forming apparatus.SOLUTION: A roller separation mechanism 800A for separating a pair of folding rollers 810 and 810b maintains the pair of folding rollers 810a, 810b separated by a pair of first folding conveyance rollers 811a, 811b and a second folding conveyance rollers 812a, 812b until the conveyed sheet flux reaches a position where the breaking processing is performed by a press unit 860.

Description

  The present invention relates to a sheet processing apparatus and an image forming apparatus, and more particularly to an apparatus for folding and binding a sheet bundle.

  2. Description of the Related Art Conventionally, an image forming apparatus such as a copying machine or a laser beam printer includes a sheet processing apparatus that takes in a sheet to be discharged after an image is formed, and folds the taken sheet or a bundle of sheets into a booklet. There is something. In such a conventional sheet processing apparatus, when a bundle of sheets is bound, for example, after stacking a predetermined number of sheets of about 20 sheets or less, the sheet bundle is folded by a stitching / folding machine as a folding means, so that the sheet bundle is booklet. Shape. Note that the sheet bundle folded by such a stitching / folding machine includes a simply folded sheet bundle, a sheet bundle folded by saddle stitching, and bound with an adhesive without binding with a thread or staple (wireless binding). And a folded sheet bundle.

  However, since any sheet bundle has some elasticity, the folded end of the sheet bundle swells and bends into a U shape after being folded. Since such a sheet bundle cannot be placed in a flat state, it becomes unstable and easily collapses when stacked, so that it is difficult to store and transport the stacked sheets.

  Therefore, in order to prevent such a problem, there is a sheet processing apparatus including a press unit having an end processing roller that clamps a folded end portion of a sheet bundle from both front and back surfaces (see Patent Document 1). In this press unit, the end processing roller is caused to travel along the folding top portion with the folding end portion sandwiched therebetween, thereby performing a crushing process for crushing the bent bending end portion.

JP 2008-184111 A

  By the way, in such a conventional sheet processing apparatus, when the folding end portion is crushed by the press unit, after the leading end portion of the sheet bundle that has passed through the pair of folding rollers reaches the press unit, the sheet bundle is stopped. The end processing roller is moved from Here, when the thickness of the folded sheet bundle is thick, the folded end portion of the sheet bundle between the innermost sheet that is the innermost sheet of the sheet bundle and the outermost sheet that is the outermost sheet of the sheet bundle. An inclined surface of the cross section of the fore edge on the opposite side is produced. Depending on the sheet size, when the sheet bundle is stopped, the edge edge of the sheet bundle may be positioned in the nip region of the pair of folding rollers.

  In this case, as shown in FIG. 13, the nip pressure of the pair of folding rollers 810 is applied to the inclined surface of the end portion of the sheet bundle PA, and a force for moving the sheet bundle PA in the downstream direction is generated. Here, the nip pressure of the folding roller pair 810 is larger than the nip pressure of the conveying roller that conveys the sheet bundle PA folded by the folding roller pair 810 to the press unit. For this reason, when a force that moves the sheet bundle PA in the downstream direction is generated by the pair of folding rollers 810, the sheet bundle PA moves, and the stop position accuracy of the folded end portion of the sheet bundle PA becomes unstable. As a result, since the back portion (folded end portion) of the sheet bundle (booklet) to be processed comes off from the end processing roller, the folded end portion cannot be sufficiently crushed and the foldability is lowered. .

  If the width of the edge processing roller in the sheet bundle conveying direction is increased, the crushing process can be performed even when the folded end of the sheet bundle is detached from the edge processing roller, but the apparatus is increased in size. Further, the folding roller pair may be arranged at a position where no nip pressure is applied to the end edge of the sheet bundle, but in this case, a sheet bundle of the same size can be processed. Cannot process sheet bundles of different sizes.

  Therefore, the present invention has been made in view of such a situation, and an object of the present invention is to provide a sheet processing apparatus and an image forming apparatus that can reliably perform the crushing process of the folded end portion of the sheet bundle. Is.

  The present invention relates to a sheet processing apparatus in which a folded end portion of a folded sheet bundle is crushed after the sheet bundle is folded in two, and the folded end portion is conveyed as a downstream end in the sheet conveying direction while folding the sheet bundle in two. A pair of folding rollers that can be contacted and separated, a crushing portion that crushes a folded end portion of a sheet bundle that is folded by the pair of folding rollers, and a position where a crushing process is performed on the sheet bundle that is folded by the pair of folding rollers. A pair of conveying rollers for conveying the sheet to the sheet and a separating mechanism for separating the pair of folding rollers, and the folding end of the sheet bundle conveyed by the pair of conveying rollers is crushed by the separating mechanism. It is characterized in that it is in a state of being separated before reaching the position where the operation is performed.

  As in the present invention, the folding end of the folding end of the sheet bundle is made by separating the folding roller pair until the sheet bundle conveyed by the conveying roller pair reaches a position where the crushing process is performed. It can be done reliably.

1 is a diagram illustrating a configuration of an image forming apparatus including a sheet processing apparatus according to an embodiment of the present invention. The figure explaining the structure of the finisher which is the said sheet processing apparatus. FIG. 3 is a control block diagram for controlling a saddle stitch bookbinding apparatus provided in the image forming apparatus and the finisher. The control block diagram of the said saddle stitch bookbinding apparatus. FIG. 3 is a perspective view of a roller separation mechanism that is provided in the saddle stitch binding apparatus and separates a pair of folding rollers. The perspective view of the press unit provided in the said saddle stitch bookbinding apparatus. The inside explanatory drawing of the above-mentioned press unit. The flowchart explaining the saddle stitch bookbinding operation | movement of the said saddle stitch bookbinding apparatus. FIG. 6 is a first diagram illustrating a saddle stitch bookbinding operation of the saddle stitch bookbinding apparatus. The 2nd figure explaining the saddle stitch bookbinding operation | movement of the said saddle stitch bookbinding apparatus. FIG. 10 is a third diagram illustrating the saddle stitch bookbinding operation of the saddle stitch bookbinding apparatus. The figure explaining press processing operation of the above-mentioned press unit. The figure explaining the subject of the conventional sheet processing apparatus.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail based on the drawings. FIG. 1 is a diagram illustrating a configuration of an image forming apparatus including a sheet processing apparatus according to an embodiment of the present invention.

  In FIG. 1, 600 is an image forming apparatus, 602 is an image forming apparatus main body (hereinafter referred to as apparatus main body), 650 is a document reading unit (image reader) provided on the upper part of the apparatus main body 602, and 651 is a plurality of documents automatically. This is a document conveying device for automatically reading.

  The apparatus main body 602 includes paper cassettes 909a and 909b on which normal sheets P for image formation are stacked, an image forming unit 603 that forms a toner image on a sheet using an electrophotographic process, and a toner image formed on the sheet. A fixing unit 904 and the like are provided. Further, an operation unit 601 is connected to the upper surface of the apparatus main body 602 so that a user can perform various inputs / settings on the apparatus main body 602, and a finisher 500 that is a sheet processing apparatus is connected to the side of the apparatus main body 602. Yes. Reference numeral 960 denotes a CPU circuit unit that is a control unit that controls the apparatus main body 602 and the finisher 500.

  In such an image forming apparatus 600, when an image of a document (not shown) is formed on a sheet, first, an image sensor transported by the document transport device 651 is used as an image sensor provided in the document reading unit 650. Read by 650a. Thereafter, the read digital data is input to the exposure unit 604, and the exposure unit 604 irradiates light corresponding to the digital data to the photosensitive drum 914 (914a to 914d) provided in the image forming unit 603. When light is irradiated in this way, an electrostatic latent image is formed on the surface of the photosensitive drum, and by developing the electrostatic latent image, toner images of colors of yellow, magenta, cyan, and black are formed on the surface of the photosensitive drum. Is formed.

  Next, the four color toner images are transferred onto the sheet fed from the sheet feeding cassettes 909 a and 909 b, and then the toner image transferred onto the sheet is permanently fixed by the fixing unit 904. Note that after fixing the toner image in this manner, in the mode in which an image is formed on one side of the sheet, the sheet is discharged from the discharge roller pair 907 to the finisher 500 as it is.

  In the mode in which images are formed on both sides of the sheet, the sheet is transferred from the fixing unit 904 to the reversing roller 905, and then the reversing roller 905 is reversed at a predetermined timing so that the sheet is conveyed to the duplex conveying rollers 906a to 906f. Transport in the direction of. Thereafter, the sheet is conveyed again to the image forming unit 603, and toner images of four colors of yellow, magenta, cyan, and black are transferred to the back surface. The sheet having the four-color toner image transferred on the back surface is conveyed again to the fixing unit 904 to fix the toner image, and then discharged from the discharge roller pair 907 to be side portions of the apparatus main body 602. The finisher 500 is connected to the finisher 500.

  The finisher 500 sequentially takes in the sheets discharged from the apparatus main body 602, aligns the plurality of taken-in sheets and bundles them into one bundle, and performs punching to make a hole near the rear end of the taken-in sheets. ing. The finisher 500 performs processing such as stapling processing (binding processing) for stapling the rear end side of the sheet bundle, binding processing, and the like. The stapler 700 for stapling the sheet and the sheet bundle are folded in two. A saddle stitch bookbinding apparatus 800 for bookbinding is provided.

  As shown in FIG. 2, the finisher 500 includes an entrance roller pair 502 for taking a sheet into the apparatus, and the sheet discharged from the apparatus main body 602 is delivered to the entrance roller pair 502. At this time, the sheet delivery timing is simultaneously detected by the entrance sensor 501.

  After that, the sheet conveyed by the inlet roller pair 502 is detected by the lateral registration detection sensor 504 while passing through the conveyance path 503, and how much is the center (center) position of the finisher 500. It is detected whether a deviation in the width direction has occurred. In addition, after the shift in the width direction (hereinafter referred to as a lateral registration error) is detected in this way, the shift unit 508 moves forward or backward while the sheet is being conveyed to the shift roller pairs 505 and 506. The sheet shift operation is performed by moving the predetermined amount.

  Next, the sheet is conveyed by the conveyance roller 510 and the separation roller 511 and reaches the buffer roller pair 515. Thereafter, when the paper is discharged to the upper tray 536, the upper path switching member 5118 is brought into a broken line state in the figure by driving means such as a solenoid (not shown). As a result, the sheet is guided to the upper path conveyance path 517 and discharged to the upper tray 536 by the upper discharge roller 520.

  When the sheet is not discharged to the upper tray 536, the sheet conveyed by the buffer roller pair 515 is guided to the bundle conveyance path 521 by the upper path switching member 518 in the state indicated by the solid line. Thereafter, the sheet passes through the transport path sequentially by the transport roller 522 and the bundle transport roller pair 524. Next, when the conveyed sheet is discharged to the lower stacking tray 537, the sheet is conveyed to the lower path 526 by the saddle path switching member 525 in the state shown by the solid line. Thereafter, the sheet is discharged to the intermediate processing tray 538 by the lower discharge roller pair 528. Then, the discharged sheets are aligned while the sheets are sequentially stacked by the return means such as the paddle 531 and the belt roller 558, and an intermediate process as a sheet stacking unit for performing processing on the aligned and stacked sheet bundle. A predetermined number of sheets are aligned on the tray.

  Next, the sheet bundle subjected to the alignment process on the intermediate processing tray in this manner is subjected to a binding process by a stapler 532 constituting a binding unit as necessary, and thereafter, a lower stacking tray by a bundle discharge roller pair 530. The paper is discharged to 537. The stapler 532 is movable in a direction orthogonal to the sheet discharge direction (hereinafter referred to as a depth direction), and can bind a plurality of locations at the rear end portion of the sheet bundle.

  On the other hand, when the sheet is subjected to saddle (saddle stitching) processing, the saddle path switching member 525 is moved to a position indicated by a broken line by driving means such as a solenoid (not shown). Thus, the sheet is conveyed to the saddle path 533 and guided to the saddle stitch bookbinding apparatus 800 by the saddle entrance roller pair 801.

  Next, the sheet sent to the saddle stitch bookbinding apparatus 800 is delivered to the saddle entrance roller pair 801, and the carry-in entrance is selected by a switching member 802 operated by a solenoid according to the size, and stored as a sheet stacking means. It is carried into the guide 803. The carried-in sheet is continuously conveyed by a sliding roller 804 having a sliding property on the roller surface.

  The saddle inlet roller pair 801 and the sliding roller 804 are driven by an inlet roller motor M1 and controlled by an inlet sensor S1. The sheet conveyed to the storage guide 803 has an end (downstream end in the conveyance direction) hitting an end stopper 805 that has been moved to a predetermined position in advance according to the sheet size (length in the sheet conveyance direction). It is conveyed until it touches. The end stopper 805 is controlled by the end stopper movement sensor S2, is movable in the sheet conveyance direction along the sheet guide surface of the storage guide 803, and is driven by the end stopper movement motor M2 to convey the sheet. Can be moved to. Further, the end stopper 805 has a regulating surface 805a protruding from the storage guide 803, and receives and holds the downstream end portion of the sheet conveyed to the storage guide 803 by the regulating surface 805a.

  A stapler 820 that is a binding means that binds the central portion in the conveyance direction of a bundle of a plurality of sheets stored in the storage guide 803 is provided in the middle of the storage guide 803 so as to face the storage guide 803. Yes. The stapler 820 is divided into a driver 820a that protrudes the needle and an anvil 820b that bends the protruded needle. When the storage of the sheet is completed, the stapler 820 staples the central portion in the conveyance direction of the bundle made of the sheet.

  On the downstream side of the stapler 820, a pair of folding rollers 810 a and 810 b that constitute a folding unit that folds the sheet bundle stored in the storage guide 803 in the center in the conveyance direction, and a protruding member 830 sandwich the storage guide 803. It is provided so as to face each other. The protrusion member 830 protrudes toward the center in the conveyance direction of the sheet bundle stored in the storage guide 803 by driving the protrusion motor M3.

  When the sheet bundle bound by the stapler 820 is folded, the sheet bundle at the staple position is set so that the staple position (central portion in the conveyance direction) of the sheet bundle becomes the nip position of the folding roller pair 810 after the staple process is finished. Move. Thereafter, by protruding the protruding member 830, the sheet bundle can be folded in half at the center while pushing the sheet bundle into the nip of the pair of folding rollers 810a and 810b. When the sheet bundle is folded without performing the binding process, the sheet bundle is moved so that the central portion in the conveyance direction of the sheet bundle stored in the storage guide 803 is the nip position between the pair of folding rollers 810a and 810b. Thereafter, the protruding member 830 protrudes.

  Note that the movement of the sheet bundle from the sheet storage position (each receiving position) to the stapling position and from the stapling position to the folding position is performed by lowering or raising the end stopper 805 by the end stopper moving motor M2. Further, at the positions of the folding roller pairs 810a and 810b, an alignment plate pair 825 having a surface protruding to the storage guide 803 while surrounding the outer peripheral surfaces of the folding roller pairs 810a and 810b is provided. The alignment plate pair 825 is stored in the storage guide 803 by detecting the position by the alignment plate movement HP sensor S5 and moving in the width direction orthogonal to the sheet conveyance direction under the driving of the alignment plate moving motor M5. Alignment (positioning) of the sheet in the width direction is performed.

  Next, the sheet bundle folded in two by the pair of folding rollers 810a and 810b is crushed by the first fold conveyance roller pair 811a and 811b and the second fold conveyance roller pair 812a and 812b. It is conveyed to a press unit 860 which is a section. Then, after the downstream end (front end) in the sheet conveyance direction is conveyed to the press unit 860, the first fold conveyance roller pair 811a and 811b and the second fold conveyance roller pair 812a and 812b, which are conveyance roller pairs, are stopped and the sheet bundle is stopped. Stop.

  In addition, after the sheet bundle ejecting operation by the ejecting member 830 is completed and the leading ends of the sheet bundle reach the first folding conveyance roller pair 811a and 811b, the folding roller pair 810a and 810b are brought out of the pressure contact state by a roller separation mechanism described later. The separated state. Thereafter, the protruding member 830 is returned to the home position. The home position of the protrusion member 830 is a position retracted from the storage guide 803, and this home position is controlled by the protrusion sensor S3. Further, when the protruding member 830 is returned, the load resistance due to the nip pressure of the folding roller pair 810a, 810b when the protruding member 830 is returned by moving the folding roller pair 810a, 810b away from the pressure contact state. Can be reduced.

  After that, the press roller pair 861 of the press unit 860 is folded by moving the press roller pair 861 along the folding end of the sheet bundle while pressing the back folded portion of the sheet bundle (booklet) whose conveyance is stopped. A refolding process is performed on the end portion. Next, after the refolding process is performed by the press unit 860 as described above, the sheet bundle is conveyed again in the downstream direction and discharged to the folded bundle discharge tray 842.

  The fold bundle discharge tray 842 rotates the conveyor on the tray surface by the fold bundle discharge tray motor M8, and sequentially moves the discharged sheet bundle in the downstream direction while being controlled by the fold bundle discharge tray sensor S9. Load a bunch. The folding roller pair 810, the first folding conveyance roller pair 811 and the second folding conveyance roller pair 812 are controlled to rotate at the same speed by the same folding conveyance motor M4 based on the detection of the folding conveyance sensor S4.

  FIG. 3 is a control block diagram for controlling the image forming apparatus 600 and the saddle stitch bookbinding apparatus 800. As illustrated in FIG. 3, the CPU circuit unit 960 includes a CPU 629, a ROM 631, and a RAM 655. The CPU circuit unit 960 controls the document feeding device control unit 632, the image reader control unit 633, the image signal control unit 634, the printer control unit 635, the saddle stitch binding device control unit 636, and the external interface 637. Note that the CPU circuit unit 960 performs control according to the program stored in the ROM 631 and the setting of the operation unit 601.

  The document feeder controller 632 controls the document feeder 651, and the image reader controller 633 controls the image reader. The printer control unit 635 controls the apparatus main body 602. The saddle stitch bookbinding controller 636 is provided in a finisher controller (not shown) mounted on the finisher 500 and controls the saddle stitch bookbinding apparatus 800. In the present embodiment, a configuration in which the finisher control unit (saddle stitch bookbinding device control unit 636) is mounted on the saddle stitch bookbinding device 800 will be described. However, the present invention is not limited to this, and a finisher control unit (saddle stitch bookbinding device control unit 636) is provided in the device body 602 integrally with the CPU circuit unit 960, and the saddle stitch bookbinding device from the device body 602 side. 800 may be controlled.

  The RAM 655 is used as an area for temporarily storing control data and a work area for calculations associated with control. An external interface 637 is an interface from a computer (PC) 620, which develops print data into an image and outputs the image to the image signal control unit 634. An image read by the image sensor is output from the image reader control unit 633 to the image signal control unit 634, and an image output from the image signal control unit 634 to the printer control unit 635 is input to the exposure control unit.

  In the present embodiment, the saddle stitch bookbinding control unit 636 performs drive control of the finisher 500 by exchanging information with the CPU circuit unit 630. Further, the saddle stitch bookbinding apparatus control unit 636 may be disposed integrally with the CPU circuit unit 630 on the apparatus main body side, and the finisher 500 may be directly controlled from the apparatus main body side.

  FIG. 4 is a control block diagram of the saddle stitch bookbinding apparatus 800 according to the present embodiment. As shown in FIG. 4, the saddle stitch bookbinding apparatus control unit 636 includes a CPU (microcomputer) 701, a RAM 702, a ROM 703, an input / output unit (I / O) 705, a communication interface 706, and a network interface 704. Various sensor signals are input to the input port of the I / O 705, and the output port of the I / O 705 is connected to each drive system connected via a control block (not shown) and various drivers (not shown). Has been.

  Then, the CPU 701 controls the driving of the inlet roller motor M1 by the inlet sensor S1, the driving control of the end stopper moving motor M2 by the end stopper moving sensor S2, and the driving of the thrust motor M3 by the thrust sensor S3 via the conveyance control unit 708. Execute drive control. Further, the CPU 701 executes drive control of the folding conveyance motor M4 by the folding conveyance sensor S4 and drive control of the alignment plate movement motor M5 by the alignment plate movement HP sensor S5 via the conveyance control unit 708. Further, the CPU 701 controls the driving of the roller separation driving motor M6 by the roller separation HP sensor S6 and the folding detection sensor S7 via the conveyance control unit 708, and the driving of the folding bundle discharge tray motor M8 by the folding bundle discharge tray sensor S9. Control is executed. Further, the CPU 701 executes drive control of the press drive motor M7 by the pre-press fold detection sensor S8 via the conveyance control unit 708.

  FIG. 5 is a perspective view of a roller separation mechanism 800A that is a separation mechanism that separates the pair of folding rollers 810a and 810b, which are a pair of sheet conveyance rotators. As shown in FIG. 5, the pair of folding rollers 810 a and 810 b includes an upper roller arm plate (front) 813, an upper roller arm plate (back) 814, a lower roller arm plate (front) 815, and a lower roller arm plate (back) 816. Is supported via bearing members 824a to 824d.

  In the present embodiment, the folding roller 810a, which is the first rotating body that can contact and separate the folding roller pair 810a, 810b, is an upper roller arm plate 813 that is a first swinging member that is provided oppositely. , 814 are rotatably supported. Further, the folding roller 810b, which is the second rotating body, is rotatably supported by the lower roller arm plates 815, 816, which are the second swinging members provided to face each other.

  The upper roller arm plates 813 and 814 and the lower roller arm plates 815 and 816 are biased by pressure springs 817a and 817b so that the pair of folding rollers 810a and 810b are in pressure contact with each other. Further, the upper roller arm plates 813 and 814 and the lower roller arm plates 815 and 816 rotatably support the pair of folding rollers 810a and 810b at one swinging end portion (one end portion). Further, the saddle stitch bookbinding apparatus 800 is supported by a side plate (not shown) so as to be swingable through shafts 823a and 823b and shafts 823c and 823d.

  Further, fan gears 818a to 818d are integrally attached to the other swinging end portions (other end portions) of the upper roller arm plates 813 and 814 and the lower roller arm plates 815 and 816, respectively. The roller separation mechanism 800A is provided with drive transmission gears 816a and 817 so as to mesh with the fan gears 818a and 818b to swing the upper roller arm plate 813 and the lower roller arm plate 815. In addition, drive transmission gears 821 and 822 are provided so as to mesh with the fan gears 818c and 818d to swing the upper roller arm plate 814 and the lower roller arm plate 816.

  The drive transmission gears 816a and 817 are rotated by driving from the roller separation drive motor M6 that is transmitted via the drive transmission gear 815a. Further, when the drive transmission gears 816a and 817 are rotated in this manner, the fan gear 818a of the upper roller arm plate 813 and the fan gear 818b of the lower roller arm plate 815 are rotated, and accordingly, the upper roller arm plate 813 and the lower roller arm are rotated. The plate 815 swings.

  Further, a drive transmission gear 820 is coaxially disposed on the drive transmission shaft 819 to which the drive transmission gear 815a is fixed, and the drive transmission gears 821 and 822 are roller separation drive transmitted via the drive transmission gear 820. It is rotated by driving from the motor M6. Further, when the drive transmission gears 821 and 822 are rotated in this manner, the fan gear 818c of the upper roller arm plate 814 and the fan gear 818d of the lower roller arm plate 816 are rotated, and accordingly, the upper roller arm plate 814 and the lower roller arm are rotated. The plate 816 swings. By driving the roller separation drive motor M6 in this way, the upper roller arm plates 813 and 814 and the lower roller arm plates 815 and 816 can be swung synchronously, thereby the folding roller pairs 810a and 810b. Can also be performed synchronously.

  Here, in the roller separation mechanism 800A, when the folded end portion tip (top portion) of the folded sheet bundle reaches the first fold conveying roller pair 811a, 811b, and the folded bundle detection sensor S7 detects passage of the leading end, The pair of folding rollers 810a and 810b is released from the pressure contact state to the separated state. It should be noted that when the separation state is set in this way, the separation amount (width) of the pair of folding rollers 810a and 810b is set to be larger than the thickness of the maximum number of sheet bundles. As a result, the folding roller pair 810a and 810b can be separated from the sheet bundle after the bent end of the sheet bundle reaches the first folding conveying roller pair 811a and 811b. Thereafter, the sheet bundle is conveyed by the first folding conveyance roller pair 811a and 811b, and the leading end portion passes the pre-press detection sensor S8. Further, after being conveyed to the press unit 860 by the second fold conveying roller pair 812a, 812b, it stops.

  FIG. 6 is a perspective view of the press unit 860, and FIG. 7 is an internal explanatory diagram of the press unit 860. Here, as shown in FIG. 6, the press unit 860 includes a base sheet metal 863 incorporating a main part, a press roller pair 861, a sheet guide 871 that guides the sheet bundle to the press roller pair 861, and the like. have.

  The press holder 862 extends in the width direction perpendicular to the sheet bundle discharge direction, and is connected to two parallel slide shafts 864 and 865 fixed to a side plate (not shown) of the press unit 860 via slide bearings 874 and 875. And is slidably supported. Further, the press holder 862 is fixed to a timing belt 868 that is rotationally driven by the press drive motor M7. When the press drive motor M7 rotates and the timing belt 868 moves, the press holder 862 moves while being supported by the slide shafts 864 and 865. To do.

  In FIG. 7, reference numerals 873a and 873b denote press arms that are swingably supported by swinging shafts 874a and 874b fixed to a frame 839 via bearings. A pair of press rollers 861a and 861b are rotatably attached to one end of the press arms 873a and 873b via roller shafts 872a and 872b, respectively. Further, tension springs 875a and 875b are hung on the other ends of the press arms 873a and 873b and the frame 839, and the press roller pairs 861a and 861b are brought into pressure contact with each other by the tension springs 875a and 875b. . When the sheet bundle is inserted into the press roller pair 861a and 861b, the press arms 873a and 873b rotate around the swinging shafts 874a and 874b against the tension springs 875a and 875b, and the rollers are separated. .

  In FIG. 6, 883 is a gear provided on the press holder 862 to rotate the pair of press rollers 861 a and 861 b. This gear 883 is provided on the base metal plate 863 and extends parallel to the slide shafts 864 and 865. The rack gear 851 is engaged. When the press holder 862 moves while being supported by the slide shafts 864 and 865 by the press drive motor M7, the gear 883 rotates while meshing with the rack gear 851. The gear 883 and the press roller pair 861a and 861b are connected by a gear train (not shown). When the gear 883 rotates in this way, the press roller pair 861a and 861b also rotate. Each gear train is set so that the moving speed of the press holder 862 and the peripheral speeds of the two press roller pairs 861a and 861b are equal.

  Here, when the folded sheet bundle is crushed by the press roller pair 861, the first and second fold conveying roller pairs 811a, 811b, 812a, and 812b are held. Thus, when the crushing process is performed, the sheet bundle is not displaced due to the movement of the press roller pair 861. Note that the leading edge stop position (press leading edge position) of the sheet bundle during the crushing process is provided in the conveyance guide 814a shown in FIG. 3 so that the relative relationship with the press roller pair 861 is constant regardless of the size. Control is based on a detection signal from the pre-press fold detection sensor S8.

  On the other hand, the sheet bundle rear end position (press rear end position) during the crushing process is regulated so that the rear end (upstream end in the sheet conveying direction) is regulated by the storage guide 803 and the rear end is not opened. Placement is determined. When the sheet size is a sheet bundle whose rear end position is outside the area of the storage guide 803, the sheet storage guide that forms the subsequent sheet bundle even during the bending end reinforcement processing by the press roller pair 861. The storage to 803 and the alignment operation are performed. Thereby, the productivity of the apparatus is improved.

  Next, the saddle stitch bookbinding operation of the saddle stitch bookbinding apparatus 800 provided with the roller separation mechanism 800A and the press unit 860 configured as described above will be described with reference to the flowchart shown in FIG.

  When the saddle stitch binding mode is set by the user, the sheet on which the image is formed is discharged to the storage guide 803 while being guided by the switching member 802 corresponding to the size of the sheet P as shown in FIG. The Further, the sheet P is abutted against an end stopper 805 that is stopped in advance at a position suitable for the sheet size while receiving the conveying force of the sliding roller 804, and is positioned in the conveying direction.

  Next, the sheet P stored in the storage guide 803 is subjected to the following alignment and stapling after storage (S102). That is, the sheet P is positioned in the width direction by nipping and alignment by the alignment plate pair 825 that has been waiting at a position where there is no problem when the sheet is discharged. Note that this sheet storage and alignment operation is performed each time the sheet P is discharged. When the alignment of the final sheet as the sheet bundle is completed, the stapler 820 staples the central portion in the conveyance direction of the sheet bundle.

  Next, the staple-stitched sheet bundle is moved downward (in the direction of arrow D) as the end stopper 805 moves, as shown in FIG. 9B. The end stopper 805 stops at the center portion of the sheet bundle PA, that is, the staple binding portion, at a position corresponding to the nip of the folding roller pair 810.

  Next, a folding process is performed by the protruding member 830 and the pair of folding rollers 810a and 810b with respect to the sheet bundle PA (S103). That is, the protruding member 830 located at the standby position starts to move to the nip of the pair of folding rollers 810a and 810b (in the direction of arrow E). As a result, as shown in FIG. 10A, the center portion of the sheet bundle PA moves while expanding the folding roller pair 810a and 810b, and is inserted into the nip of the folding roller pair 810a and 810b to be folded. .

  At the time of this folding process, the folding roller pair 810a, 810b is driven by the folding conveyance motor M4 together with the first folding conveyance roller pair 811a, 811b and the second folding conveyance roller pair 812a, 812b. Are conveyed with the bent end as the head. Accordingly, the sheet bundle PA is conveyed to the press unit 860 through the first fold conveyance roller pair 811a and 811b and the second fold conveyance roller pair 812a and 812b while being guided by the conveyance guides 813a and 814a.

  At this time, when the fold detection sensor S7, which is a detection unit for detecting the leading edge of the sheet bundle, detects the leading edge of the sheet bundle (Y in S104), a pair of folding rollers by the roller separation mechanism 800A as shown in FIG. 10B. The separation operation of 810a and 810b is started (S105). As a result, the folding rollers 810a and 810b of the pair of folding rollers 810a and 810b move in the directions of arrows f and g as shown in FIG.

  Thereafter, the sheet bundle PA passes through the second fold conveyance roller pair 812a, 812b, and the pre-press fold detection sensor S8 detects the leading edge of the sheet bundle (Y in S106). Then, based on the detection of the leading edge of the sheet bundle by the pre-press folding bundle detection sensor S8, thereafter, the sheet bundle PA is conveyed to a position where the leading end is nipped by the press roller pair 861.

  Here, the pair of folding rollers 810a and 810b by the roller separation mechanism 800A until the sheet bundle PA is conveyed to the position where the leading end is nipped by the press roller pair 861, which is the processing position where the crushing process is performed, as described above. Is completed (S107). Note that the roller separation speed and the sheet bundle conveyance speed are set so that this separation operation is completed before the sheet bundle PA stops at the press position. When the sheet bundle PA is conveyed to a position where the leading end is nipped by the press roller pair 861, the folding conveyance motor M4 is stopped, and the sheet bundle PA is stopped at the pressing position (S108).

  At this time, as shown in FIG. 11A, the sheet bundle PA is held by the second fold conveyance roller pair 812a and 812b near the leading end and the first fold conveyance roller pair 811a and 812b near the center. Further, since the pair of folding rollers 810a and 810b are separated from each other, the vicinity of the rear end of the sheet bundle is kept in a state where no nip pressure is applied. In addition, the protrusion member 830 moves to the retracted position again when the protrusion is completed.

  Next, press processing by the press unit 860 is performed (S109). Here, when performing this pressing process, that is, the crushing process, prior to the conveyance of the sheet bundle PA, the press holder 862 corresponds to the size (width direction) of the sheet bundle PA as shown in FIG. Waiting at the standby position (back side). Then, when the sheet bundle PA is stopped and the bent end portion of the sheet bundle PA is inserted into the sheet guide 871, the press unit 860 is driven by the press drive motor M7 and rotates the press roller pair 861 while moving the near side. The movement in the direction of arrow J is started.

  After this, the press roller pair 861 contacts the side surface near the bent end of the sheet bundle PA that is stopped and held, but the press roller pair 861 itself is rotated by driving on both sides. As shown, it is possible to smoothly run up the side surface and nip the end portion. As a result, the sheet bundle PA can be nipped by the press roller pair 861 without delay in response in synchronization with the movement of the press holder 862, so that the folded sheet bundle PA is wrinkled, torn, roller marks, etc. Does no damage. This effect does not change even if the thickness of the sheet bundle PA increases.

  Next, when the movement of the press roller pair 861 is completed and the pressing process of the sheet bundle PA is completed (Y in S110), the press unit 860 moves to the home position and opens the path in the conveyance direction of the sheet bundle PA. Thereafter, as shown in FIG. 11B, a pressing operation is started to return the pair of folding rollers 810a and 810b from the separated state to the pressed state (contact state) by the roller separating mechanism, and the sheet bundle PA Is discharged to the folding tray 840 (S111). The pressure contact operation by the roller separation mechanism may be completed by the time when the next sheet bundle is pushed out by the protruding member 830.

  By the way, in the present embodiment, as described above, after the leading end portion of the sheet bundle that has passed through the pair of folding rollers 810a and 810b is conveyed to the press unit 860, the sheet bundle is stopped. In this case, as a phenomenon of a thick half-fold sheet bundle, there is usually an inclined surface with a small cross section between the innermost sheet which is the innermost sheet of the sheet bundle and the outermost sheet which is the outermost sheet of the sheet bundle. Arise.

  Further, when the sheet bundle is stopped in this way, the edge end portion opposite to the folded end portion of the sheet bundle may coincide with the nip position of the pair of folding rollers 810a and 810b depending on the size. In this case, as shown in FIG. 13 described above, the nip pressure of the pair of folding rollers 810a and 810b is applied to the inclined surface, and accordingly, a force for moving the sheet bundle PA in the downstream direction is generated. Here, the nip pressure of the pair of folding rollers 810a and 810b is larger than the nip pressure of the pair of first folding and conveying rollers 811a and 811b and the pair of second folding and conveying rollers 812a and 812b. For this reason, when a force for moving the sheet bundle PA in the downstream direction is generated by the pair of folding rollers 810a and 810b, the sheet bundle PA is moved, and the stop position accuracy of the sheet bundle PA becomes unstable.

  However, in the present embodiment, as described above, after the folded end portion tip (top portion) of the sheet bundle reaches the first fold conveying roller pair 811a and 811b, the folded roller pair 810a and 810b are pressed. It is in a separated state. For this reason, the nip pressure of the pair of folding rollers 810a and 810b is not applied to the inclined surface of the end edge of the sheet bundle, and the sheet bundle stopping accuracy after being conveyed to the press unit 860 is stabilized.

  Further, with this configuration, it is not necessary to increase the width (sheet bundle conveyance direction) of the press roller pair 861 in consideration of the shift amount of the stop position, so that the apparatus can be miniaturized. Further, regardless of whether the sheet is a fixed size or an irregular size, the nip pressure is not applied to the inclined surface of the small edge of the sheet bundle by separating the folding rollers 810a and 810b. The degree of freedom in arrangement increases, and the entire apparatus can be reduced in size.

  Further, even when the sheet is jammed by the pair of folding rollers 810a and 810b, the take-out property of the sheet bundle can be improved by separating the pair of folding rollers 810a and 810b. Furthermore, not only the folding roller pair 810a and 810b but also the first folding conveying roller pair 811a and 811b are moved away from each other, so that the sheet bundle take-out property can be improved.

  As described above, the folding roller pair 810a and 810b are separated from each other before reaching the position where the sheet bundle is crushed and stopped, thereby improving the accuracy of the position where the sheet bundle is folded and stopped. Can be made. Thereby, the crushing process of the folded end portion of the sheet bundle can be reliably performed regardless of the sheet size.

  Heretofore, the folding roller pairs 810a and 810b are moved apart from each other regardless of the sheet size, but the present invention is not limited to this. For example, when the length of the sheet bundle in the sheet conveyance direction is stopped at a position where the leading end of the sheet bundle is crushed by the press unit 860, the rear end of the sheet bundle is more than the nip region of the pair of folding rollers 810a and 810b. There is a case where the length is located downstream in the transport direction. In such a case, the separating operation of the pair of folding rollers 810a and 810b may not be performed. In addition, when the number of sheet bundles is small and the sheet bundle is not thick, for example, when the sheet is folded or folded in two Alternatively, the separation operation by the roller separation mechanism may not be performed.

  In the present embodiment, the folded sheet bundle is conveyed to the position where the press unit 860 performs the crushing process by the first fold conveying roller pair 811a and 811b and the second fold conveying roller pair 812a and 812b. However, the present invention is not limited to this. For example, the first fold conveyance roller pair 811a and 811b may be eliminated, and the sheet may be conveyed to the press unit 860 only by the second fold conveyance roller pair 812a and 812b. With this configuration, the cost can be reduced by downsizing the device and reducing the number of components.

  The same effect can be obtained by using a conveyance belt that can hold a folded sheet bundle instead of the first folding conveyance roller pair 811a and 811b and the second folding conveyance roller pair 812a and 812b, or other sheet bundle holding means. be able to. Further, in the description so far, the press unit 860 performs the crushing process of the folded end portion of the sheet bundle. However, the folding top portion which is the folded end portion of the sheet bundle from the side along with the crushing process of the folded end portion. It is good also as what presses and performs the flattening process of a folding top part.

500 ... finisher, 600 ... image forming apparatus, 601 ... operation section, 602 ... image forming apparatus main body, 800 ... saddle stitch bookbinding section, 800A ... roller separation mechanism 810a, 810b ... folding roller pair, 811a, 811b ... first fold conveyance Roller pair, 812a, 812b ... 2nd folding conveying roller pair, 860 ... Press unit, 861 ... Press roller pair, P ... Sheet, PA ... Sheet bundle, S7 ... Fold detection sensor

Claims (6)

In the sheet processing apparatus in which the folded end portion of the folded sheet bundle is crushed after the sheet bundle is folded in two,
A pair of folding rollers that can be separated from each other while conveying the folded end as a downstream end in the sheet conveying direction while folding the sheet bundle in two,
A crushing portion for crushing a folded end portion of the sheet bundle folded by the pair of folding rollers;
A pair of conveying rollers that conveys the sheet bundle folded by the pair of folding rollers to a position where a crushing process is performed by the crushing unit;
A separation mechanism that separates the pair of folding rollers,
The sheet processing apparatus, wherein the pair of folding rollers is separated by the separation mechanism until the folded end of the sheet bundle conveyed by the conveyance roller pair reaches a position where the crushing process is performed. A detection unit that detects a bent end portion of the sheet bundle conveyed by the conveyance roller,
The sheet processing apparatus according to claim 1, wherein the separating operation of the pair of folding rollers by the separating mechanism is started based on detection of a folded end portion of the sheet bundle by the detecting unit.   3. The sheet processing apparatus according to claim 1, wherein the pair of folding rollers is returned to a contact state by the separation mechanism after the crushing process by the crushing unit is completed.   When the sheet conveyance direction length of the sheet bundle reaches the position where the sheet bundle is subjected to the crushing process, the upstream end of the sheet bundle in the sheet conveyance direction is positioned downstream of the nip region of the pair of folding rollers in the sheet conveyance direction. 4. The sheet processing apparatus according to claim 1, wherein, in the case of such a length, the separating operation of the pair of folding rollers by the separating mechanism is not performed. 5.   5. The sheet processing apparatus according to claim 1, wherein a separation amount of the folding roller pair by the separation mechanism is larger than a thickness of a sheet bundle to be crushed.   An image forming unit that forms an image on a sheet, and a sheet processing apparatus according to claim 1 that performs processing on a sheet bundle composed of a plurality of sheets on which images are formed. An image forming apparatus.

Images