JP2010189096A - Sheet processing device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase efficiency in an operation space of a gripping member on the inside of a device so that the gripping member does not interfere with the other apparatus on the inside of the device. <P>SOLUTION: This sheet processing device has a storage guide 803 for successively stacking a carried sheet, a stapler 820 for selectively applying processing in a predetermined processing position to a sheet bundle composed of a plurality of sheets stacked on the storage guide 803, and a sheet gripping member 802 gripping and moving an end part of the sheet bundle stacked on the storage guide 803 to the processing position. The sheet gripping member 802 releases gripping of the sheet bundle once in a first position for gripping the end part of the sheet bundle till then before moving the sheet bundle to the processing position, and moves to a second position for approaching the end part of the sheet bundle from the first position in the opposite direction of the direction for moving the sheet bundle to the processing position, and moves the sheet bundle to the processing position after gripping the sheet bundle again in the second position. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sheet processing apparatus that selectively processes a sheet bundle composed of a plurality of sheets, and an image forming apparatus having the sheet processing apparatus.

  2. Description of the Related Art Conventionally, a sheet processing apparatus connected to an image forming apparatus performs bookbinding by performing predetermined processing on a sheet output from the image forming apparatus as a sheet bundle composed of a plurality of sheets. As one form of bookbinding, there is a saddle stitch bookbinding in which a central portion of a sheet bundle is bound and the binding portion is folded in half.

  In the saddle stitch bookbinding process, the conveyed sheets are sequentially stacked, and the aligned sheet bundle is moved to a processing position (binding processing position or folding processing position) before processing. However, when the sheet bundle is moved to the processing position, there is a problem that the consistency of the sheet bundle is impaired. Further, for example, when a sheet bundle made of sheets such as thin paper having a small basis weight is moved, there is a problem that the sheet bundle is buckled due to weak stiffness. Therefore, a configuration has been proposed in which a gripping member for gripping a sheet bundle is provided, and when the sheet bundle is moved to the processing position, the sheet bundle is gripped using the gripping member and moved to the processing position (patent) Reference 1).

JP 08-295458

  However, in order to move the sheet bundle using the gripping member, it is necessary to secure a space for moving the gripping member inside the apparatus so that the gripping member does not interfere with other devices inside the apparatus. There was a risk of increasing the size of the apparatus.

  Therefore, an object of the present invention is to increase the efficiency of the operating space of the gripping member inside the apparatus so that the gripping member does not interfere with other devices inside the apparatus and the apparatus is not enlarged by securing the movement space of the gripping member. It is to plan.

  The present invention provides a sheet stacking unit for sequentially stacking conveyed sheets, and a process for selectively processing a sheet bundle composed of a plurality of sheets stacked on the sheet stacking unit at a predetermined processing position. And sheet gripping means for gripping and moving the end of the sheet bundle stacked on the sheet stacking means to the processing position, and the sheet gripping means moves the sheet bundle to the processing position. Previously, the gripping of the sheet bundle is once released at the first position where the end of the sheet bundle has been gripped so far, and the direction is opposite to the direction in which the sheet bundle is moved to the processing position, The sheet bundle is moved from the first position in a direction approaching the end of the sheet bundle, the sheet bundle is gripped again at the moved second position, and then the sheet bundle is moved to the processing position. Features.

  According to the present invention, before the sheet bundle is moved to the processing position, the sheet bundle is moved again in the direction opposite to the direction in which the sheet bundle is moved to the processing position, and the sheet bundle is gripped again. Therefore, the movement space from the gripping position (first position) before the gripping of the sheet bundle to the processing position can be minimized, and the operation space of the sheet gripping means in the apparatus can be made efficient. it can. Thereby, it is possible to prevent the sheet gripping means from interfering with other devices inside the apparatus, and it is also possible to prevent the apparatus from becoming large due to securing the movement space of the sheet gripping means.

Overall configuration diagram showing the configuration of the main part of the image forming apparatus Overall block diagram showing the configuration of a controller that controls the entire image forming apparatus Plan view showing an operation display device in the image forming apparatus (A), (b), and (c) are bookbinding mode setting screens. Sectional view showing the schematic configuration of the finisher Flow chart showing the flow of operations in bookbinding mode Sectional view showing the flow of sheets in the finisher during bookbinding mode Sectional view showing the flow of sheets in the finisher during bookbinding mode (A) (b) (c) is a schematic cross-sectional view showing the difference in operation of the sheet gripping member due to the difference in sheet gripping position

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in the following embodiments should be appropriately changed according to the configuration of the apparatus to which the present invention is applied and various conditions. Therefore, unless specifically stated otherwise, the scope of the present invention is not intended to be limited thereto.

  Here, an image forming apparatus provided with an image forming apparatus main body and a sheet processing apparatus will be described as an example.

(Overall configuration of image forming apparatus)
First, the overall configuration of the image forming apparatus will be described with reference to FIG. FIG. 1 is an overall configuration diagram illustrating a configuration of a main part of the image forming apparatus.

  As shown in FIG. 1, the image forming apparatus includes an image forming apparatus main body 10 and a finisher 500 as a sheet processing apparatus. The image forming apparatus main body 10 includes an image reader 200 that reads an image of a document and a printer 300 that records an image on a sheet.

  A document feeder 100 is mounted on the image reader 200. The document feeder 100 feeds documents set upward on the document tray one by one in order from the first page, conveys them to the reading position on the platen glass 102 through a curved path, and then discharges them to the outside. The sheet is discharged toward the tray 112.

  When the original passes through the reading position on the platen glass 102, the image of the original is read by the scanner unit 104 held at a position corresponding to the reading position. This reading method is generally referred to as document scanning. Specifically, when the document passes through the reading position, the reading surface (image surface) of the document is irradiated with light from the lamp 103 of the scanner unit 104, and the reflected light from the document passes through the mirrors 105, 106, and 107. Through the lens 108. The light that has passed through the lens 108 forms an image on the imaging surface of the image sensor 109.

  By transporting the document so as to pass through the reading position in this way, document scanning is performed in which the direction perpendicular to the document transport direction is the main scanning direction and the transport direction is the sub-scanning direction. That is, when the original passes through the reading position, the entire original image is read by conveying the original in the sub-scanning direction while reading the original image by the image sensor 109 line by line in the main scanning direction. The image optically read in this way is converted into image data by the image sensor 109 and output. Image data output from the image sensor 109 is subjected to predetermined processing in an image signal control unit 922 (see FIG. 2) described later, and then input as a video signal to the exposure control unit 110 of the printer 300.

  It is also possible to read the image of the document by transporting the document onto the platen glass 102 by the document feeder 100 and stopping it at a predetermined position, and scanning the scanner unit 104 in the sub-scanning direction in this state. This reading method is a so-called fixed document reading.

  When reading a document without using the document feeder 100, first, the user lifts the document feeder 100 and places the document on the platen glass 102. Then, the original is read by scanning the scanner unit 104 in the sub-scanning direction. That is, when reading a document without using the document feeder 100, a fixed document reading is performed.

  The exposure control unit 110 of the printer 300 modulates and outputs a laser beam based on the input video signal, and the laser beam is irradiated onto the photosensitive drum 111 while being scanned by the polygon mirror 110a. An electrostatic latent image corresponding to the scanned laser beam is formed on the photosensitive drum 111. Here, as will be described later, the exposure control unit 110 outputs a laser beam so that a correct image (an image that is not a mirror image) is formed during document fixed reading.

  The electrostatic latent image on the photosensitive drum 111 is visualized as a developer image by a developer supplied from a developing unit 113 that forms an image forming unit together with the photosensitive drum 111. In addition, at a timing synchronized with the start of laser light irradiation, the sheet is fed from each of the cassettes 114 and 115, the manual feeding portion 125, or the duplex conveyance path 124. This sheet is conveyed between the photosensitive drum 111 and the transfer unit 116. The developer image formed on the photosensitive drum 111 is transferred onto the sheet fed by the transfer unit 116.

  The sheet onto which the developer image has been transferred is conveyed to the fixing unit 117, and the fixing unit 117 fixes the developer image on the sheet by applying heat and pressure to the sheet. The sheet that has passed through the fixing unit 117 is discharged from the printer 300 to the outside (finisher 500) through the switching member 121 and the discharge roller 118.

  Here, when the sheet is discharged with its image forming surface facing downward (face down), the sheet that has passed through the fixing unit 117 is once guided into the reversing path 122 by the switching operation of the switching member 121. After the trailing edge of the sheet passes through the switching member 121, the sheet is switched back and discharged from the printer 300 by the discharge roller 118. Hereinafter, this discharge form is called reverse discharge. The reverse discharge is performed when an image read using the document feeder 100 is formed, or when an image is formed in order from the first page, such as when an image output from a computer is formed. The order of the discharged sheets is the correct page order.

  In addition, when a hard sheet such as an OHP sheet is fed from the manual feeding unit 125 and an image is formed on the sheet, the image forming surface is faced up without leading the sheet to the reverse path 122 (face up). ) By the discharge roller 118.

  Further, when double-sided recording for image formation is set on both sides of the sheet, the sheet is guided to the reverse path 122 by the switching operation of the switching member 121 and then conveyed to the double-sided conveyance path 124. Control is performed so that the sheet guided to the duplex conveyance path 124 is fed again between the photosensitive drum 111 and the transfer unit 116 at the timing described above.

  The sheet discharged from the printer 300 is sent to the finisher 500. The finisher 500 selectively performs end binding processing, saddle stitching processing, center folding processing, and the like.

(Controller of image forming apparatus)
Next, the configuration of a controller that controls the entire image forming apparatus will be described with reference to FIG. FIG. 2 is an overall block diagram showing a configuration of a controller that controls the entire image forming apparatus of FIG.

  As shown in FIG. 2, the controller has a CPU circuit unit 900. The CPU circuit unit 900 includes a CPU (not shown), a ROM 901, and a RAM 902, and comprehensively controls each block 911, 921, 922, 931, 941, 951 by a control program stored in the ROM 901. . The RAM 902 temporarily stores control data and is used as a work area for arithmetic processing associated with control.

  The document feeder control unit 911 drives and controls the document feeder 100 based on an instruction from the CPU circuit unit 900. The image reader control unit 921 performs drive control on the scanner unit 104 and the image sensor 109 described above, and transfers an analog image signal output from the image sensor 109 to the image signal control unit 922.

  The image signal control unit 922 converts each analog image signal from the image sensor 109 into a digital image signal, performs each process, converts the digital image signal into a video signal, and outputs the video signal to the printer control unit 931. In addition, the digital image signal input from the computer 903 via the external I / F 904 is subjected to various processes, and the digital image signal is converted into a video signal and output to the printer control unit 931. The processing operation by the image signal control unit 922 is controlled by the CPU circuit unit 900. The printer control unit 931 drives the above-described exposure control unit 110 based on the input video signal.

  The operation display device control unit 941 exchanges information between the operation display device 400 (see FIG. 1) and the CPU circuit unit 900. The operation display device 400 includes a plurality of keys for setting various functions relating to image formation, a display unit for displaying information indicating a setting state, and the like. The operation display control unit 941 outputs key signals corresponding to the operation of each key to the CPU circuit unit 900, and displays corresponding information on the display unit based on the signals from the CPU circuit unit 900.

  The finisher control unit 951 is mounted on the finisher 500, and performs drive control of the entire finisher by exchanging information with the CPU circuit unit 900. The finisher control unit 951 includes a CPU, ROM, RAM, and the like (not shown). Data is exchanged by communicating with the CPU circuit unit 900 provided on the image forming apparatus main body 10 side via a communication IC (not shown), and various programs stored in the ROM are executed based on instructions from the CPU circuit unit 900. Then, drive control of the finisher 500 is performed.

  Here, the control configuration of the saddle stitch binding unit 800 in the finisher 500 will be described specifically and simply. The finisher control unit 951 performs drive control of the following various motors. The conveyance motor M1 drives the conveyance roller pair 801. The sheet gripping motor M2 drives the sheet gripping member 802 to grip the sheet bundle or release the gripping. The sheet gripping member moving motor M3 moves the sheet gripping member 802 along the storage guide 803. The positioning motor M4 drives the sheet positioning member 804 up and down. The folding motor M5 drives the folding roller pair 810a and 810b. The thrust motor M6 drives the ejection member 830.

(Operation display device)
FIG. 3 is a plan view showing the operation display device 400 in the image forming apparatus of FIG. As shown in FIG. 3, various keys are arranged on the operation display device 400. Reference numeral 402 denotes a start key for starting an image forming operation. Reference numeral 403 denotes a stop key for interrupting the image forming operation. Reference numerals 404 to 412 and 414 denote numeric keys for setting a numerical value. Reference numeral 413 denotes an ID key, 415 denotes a clear key, and 416 denotes a reset key. Reference numeral 417 denotes a user mode key for setting various devices. In addition, the operation display device 400 is provided with a display unit 420 having a touch panel formed on the top thereof, so that a soft key can be created on the screen.

  The image forming apparatus has processing modes such as non-sorting, sorting, stapling sorting (binding mode), and bookbinding mode as processing modes. Such setting of the processing mode is performed by an input operation from the operation display device 400 (or the computer 903). For example, when setting the processing mode, if the “sorter” soft key is selected on the initial screen shown in FIG. 3, a menu selection screen is displayed on the display unit 420, and this menu selection screen is used to set the processing mode. Settings are made.

  In addition, when “application mode” which is a soft key is selected on the initial screen shown in FIG. 3, the display unit 420 is switched to a screen for selecting various modes as shown in FIG. Here, a bookbinding mode or the like performed in the saddle stitch bookbinding portion of the finisher 500 described later can be selected. Briefly, when “binding” is selected on the screen shown in FIG. 4A, a key capable of selecting a cassette storing sheets to be output is displayed as shown in FIG. 4B. Here, when a cassette storing sheets of a size to be used is selected and the “Next” soft key is pressed, as shown in FIG. 4C, a screen for setting processing for a bookbinding bundle is displayed. Here, when the bookbinding mode is selected, the center folding process for folding the center of the sheet bundle is performed, but the user can select whether or not to perform the saddle stitching process for binding the center of the sheet bundle. Select "Yes" or "Do not saddle stitch". Thereafter, when the “OK” key is pressed, the setting is completed, the screen returns to the initial screen, and the start key 402 is pressed to wait for the operation to start. Hereinafter, the configuration of the finisher and the operation of the saddle stitching processing unit will be described in detail.

(Finisher)
First, the configuration of the finisher 500 will be described with reference to FIG. FIG. 5 is a configuration diagram of the finisher 500 of FIG.

  As shown in FIG. 5, the finisher 500 has a conveyance path 520 for sequentially taking sheets discharged from the image forming apparatus main body 10, and the conveyance path 520 is provided with a plurality of conveyance roller pairs.

  A punch unit 530 is provided in the middle of the conveyance path 520. The punch unit 530 operates as necessary, and performs a punching (punching) process on the rear end portion of the conveyed sheet.

  A switching member 513 is provided at the end of the transport path 520. The switching member 513 switches the route between an upper discharge path 521 and a lower discharge path 522 connected downstream. The upper discharge path 521 performs discharge to the upper stack tray 701. On the other hand, the lower discharge path 522 discharges to the processing tray 550. The sheets discharged to the processing tray 550 are accommodated in a bundle while being sequentially aligned, and sorting and stapling are selectively performed according to settings from the operation display device 400 or the computer 903. A sheet bundle that has been selectively subjected to various processes is discharged to the stack trays 700 and 701 by a bundle discharge roller pair 551.

  The stapling process described above is performed by the stapler 560. The stapler 560 is movable in the width direction orthogonal to the sheet conveyance direction, and can be stapled at an arbitrary position on the sheet. The stack trays 700 and 701 are configured to be movable in the vertical direction. The upper stack tray 701 can receive sheets from the upper discharge path 521 and the processing tray 550. Further, the lower stack tray 700 can receive sheets from the processing tray 550. In this way, a large number of sheets can be stacked on the stack trays 700 and 701, and the stacked sheets are regulated and aligned by the rear end guide 710 extending in the vertical direction at the rear end.

  A switching member 514 is provided in the middle of the lower discharge path 522 to guide the sheet to the processing tray 550 or the bookbinding path 523. The sheet guided to the bookbinding path 523 by the switching member 514 is sent to the saddle stitch bookbinding unit 800.

(Saddle stitch bookbinding)
Next, the configuration of the saddle stitch binding unit 800 as a sheet processing apparatus will be described with reference to FIGS. 2 and 5.

  The sheets sent to the saddle stitch bookbinding unit 800 are sent to a storage guide 803 as a sheet stacking unit by a pair of conveyance rollers 801 driven by a conveyance motor M1, and sequentially stacked. The leading edge of the sheet conveyed to the storage guide 803 is received and held by the sheet positioning member 805. Further, the sheet is gripped by the rear end being pressed against the storage guide 803 by the sheet gripping member 802. The sheet gripping member 802 is driven by the sheet gripping motor M2 so that one end of the sheet (the rear end of the sheet) is pressed against the storage guide 803 every time a sheet is stacked on the storage guide 803. It is a sheet gripping means for gripping. Further, the sheet positioning member 804 receives the driving of the positioning motor M4, and the position of the other end (sheet front end) corresponding to the length in the sheet conveyance direction with reference to the position of the sheet gripping member 802. It is the receiving means which moves to. Then, the sheet gripping member 802 and the sheet positioning member 804 move a sheet bundle composed of a plurality of sheets stacked on the storage guide 803 to a predetermined processing position. At this time, the sheet positioning member 804 is moved by the positioning motor M4, and the sheet gripping member 802 is moved by the sheet gripping member moving motor M3. The movement operation of the sheet bundle to the processing position will be described in detail later.

  In the saddle stitch bookbinding portion 800, staplers 820a and anvils 820b serving as binding means, folding roller pairs 810a and 810b serving as folding means, and a protruding member 830 are provided as processing means for selectively processing the sheet bundle. Is provided. At the binding processing position of the binding means, a stapler 820a and an anvil 820b are provided to face each other with a storage guide 803 interposed therebetween. At this processing position, the stapler 820a and the anvil 820b cooperate to perform stapling on the sheet bundle stacked and stored in the storage guide 803. At the folding processing position of the folding means, the nip portion of the pair of folding rollers 810a and 810b and the protruding member 830 are provided to face each other via the storage guide 803. At this processing position, the pair of folding rollers 810a and 810b and the protruding member 830 cooperate to perform a folding process on the sheet bundle stacked and stored in the storage guide 803. The sheet bundle subjected to the folding process is guided to a conveyance path 813 and discharged onto the bookbinding tray 850 by the pair of folding conveyance rollers 811a and 811b and the pair of folding conveyance rollers 812a and 812b.

(Binding mode operation)
Next, the operation of the bookbinding mode in the finisher 500 will be described with reference to FIGS. 6, 7, and 8. FIG. 6 is a flowchart showing the flow of operations in the bookbinding mode in the saddle stitch bookbinding unit. 7 and 8 are schematic cross-sectional views showing the flow of sheets in the bookbinding mode.

  When the bookbinding mode is specified on the operation display device 400 described above and the start key 402 is pressed in step S1000, the operation in the bookbinding mode is started, and the process proceeds to step S1001. The sheet P discharged from the image forming apparatus main body 10, taken into the finisher 500, and guided to the saddle stitch bookbinding section 800 is sent into the storage guide 803 by a pair of conveyance rollers 801 that are rotationally driven by the conveyance motor M1. (See FIG. 7 (a)). When the leading edge of the sheet P sent into the storage guide 803 reaches the sheet positioning member 804 and the conveyance is stopped, it is determined in step S1001 that the stacking operation of one sheet is completed. In step S1002, the alignment member 815 operates in the width direction orthogonal to the sheet conveyance direction, and alignment in the sheet width direction is performed. The sheet positioning member 805 moves to a position corresponding to the length of the sheet P in the conveyance direction with reference to the position of the sheet gripping member 802 (the position where the trailing edge of the sheet P passes through the conveyance roller pair 801). Yes. As described above, when the leading edge of the sheet P sent to the storage guide 803 reaches the sheet positioning member 804, alignment in the sheet conveyance direction is achieved.

  After the sheet alignment operation, in step S1003, a gripping operation is performed on the sheet P conveyed to the storage guide 803. As shown in FIGS. 7A to 7C, the sheet gripping operation is performed at a first position that does not hinder the conveyance of the sheet to the storage guide 803. First, the sheet gripping member 802 moves the rear end of the sheet P to the storage guide 803 as shown in FIG. 7A at the first position until the rear end of the sheet P passes through the conveying roller pair 801. The holding posture to hold down is maintained. Then, after the alignment, the sheet gripping motor M2 is driven, and the sheet gripping member 802 that has maintained the pressing posture is moved to the first position as shown in FIG. 7B. Rotate to the retracted posture to release. Thereafter, the sheet gripping member 802 is again rotated at the first position so as to hold the rear end of the sheet P as shown in FIG. Press to 803. This series of operations is a gripping operation for gripping one end portion (sheet trailing end) of the sheet so as to press against the storage guide 803, and is performed every time a sheet is stacked on the storage guide 803.

  In step S1004, it is determined whether or not the sheet is a final sheet of a sheet bundle including a plurality of sheets. If it is not the last sheet in the sheet bundle, the process returns to step S1001 to wait for the stacking operation for the next sheet to be completed. If it is determined in step S1004 that the sheet is the last sheet in the sheet bundle, it is determined in step S1005 whether or not the sheet bundle needs to be moved to a processing position by the stapler 820 before stapling. Hereinafter, this operation is referred to as bundle movement before stapling.

  If the center of the aligned sheet bundle is already at the processing position by the stapler 820, it is determined that there is no pre-stapling bundle movement. If it is determined in step S1005 that there is no bundle movement before stapling, the process proceeds to step S1011 and the stapler 820 performs stapling processing (hereinafter referred to as saddle stitching) in the center of the sheet bundle.

  On the other hand, if the center of the aligned sheet bundle is not at the processing position by the stapler 820, it is determined that there is a bundle movement before stapling. If it is determined in step S1005 that the pre-staple bundle movement has occurred, it is determined in step S1006 whether or not to move the sheet gripping member 802 and re-hold the sheet bundle before moving the sheet bundle to the processing position. . Hereinafter, this operation is referred to as bundle re-gripping movement. Whether or not to perform the bundle re-gripping movement is determined based on two pieces of information of the sheet conveyance direction length and the sheet basis weight notified from the image forming apparatus body 10 to the finisher 500. Table 1 below shows the relationship between the operation in the bundle re-gripping movement with respect to the length in the sheet conveyance direction and the basis weight of the sheet.

As shown in Table 1, when the length of the sheet in the conveyance direction is a predetermined length (here 457.2 mm) or less, it is determined that there is no bundle re-gripping movement. Also, when the basis weight of the sheet is equal to or greater than a predetermined value (here, 64 g / m ² or more), it is determined that there is no bundle re-gripping movement. If it is determined in step S1006 that there is no bundle re-gripping movement, the process proceeds to step S1010, and the sheet holding member 802 is moved before the sheet bundle is moved to the processing position, and the sheet bundle is not re-gripped. Move the bundle to the processing position.

On the other hand, as shown in Table 1, when the length of the sheet in the conveyance direction exceeds a predetermined length (here 457.2 mm), it is determined that there is a bundle re-gripping movement. Further, when the basis weight of the sheet is less than a predetermined value (here, less than 64 g / m ² ), it is determined that there is a bundle re-gripping movement. In addition, even if the basis weight of the sheet is less than the predetermined value (here, less than 64 g / m ² ), if the length in the sheet conveyance direction is equal to or less than the predetermined length (here 309.4 mm), the alignment is performed. The center of the sheet bundle is already at the processing position by the stapler 820. For this reason, as described above, it is already determined that there is no bundle movement before stapling, and the bundle movement before stapling is not performed.

  If it is determined in step S1006 that there is a bundle re-gripping movement, the control from step S1007 is performed, and before the sheet bundle is moved to the processing position, the sheet gripping member 802 is moved and the sheet bundle is re-gripped. Is called. Specifically, first, in step S1007, the sheet gripping member 802 drives the sheet gripping motor M2 to grip the sheet bundle at the first position where the end (rear end) of the sheet bundle has been gripped so far. Release it once. Thereafter, the process proceeds to step S1008, and as shown in FIG. 7D, the sheet gripping member moving motor M3 is driven to move the sheet gripping member 802 downstream in the sheet transport direction. That is, the sheet gripping member 802 is moved in a direction opposite to the direction in which the sheet bundle is moved to the binding processing position, and in a direction approaching the end (rear end) of the sheet bundle from the first position. This moved position is set as a second position. In step S1009, the sheet gripping member 802 grips the sheet bundle P again at the second position moved as described above by driving the sheet gripping motor M2. As a result, the sheet gripping member 802 that has gripped the end portion of the sheet bundle P grips not only the end portion of the sheet bundle but also a portion closer to the center portion of the sheet bundle. When the re-grip of the sheet bundle is completed, an operation of moving the sheet bundle to the stapling position (binding processing position) is performed in step S1010. That is, the positioning motor M4 and the sheet gripping member moving motor M3 are driven, and the sheet bundle is moved by the positioning member 805 and the sheet gripping member 802 until the center position of the sheet bundle reaches the staple position by the stapler 820 (FIG. )reference). At this time, the positioning motor M4 and the sheet gripping member moving motor M3 are driven so that the positioning member 805 and the sheet gripping member 802 move in the same direction and at the same speed.

  As described above, when the bundle re-gripping movement is performed before the sheet bundle is moved to the processing position, the sheet gripping member is moved in the direction opposite to the moving direction of the sheet bundle and the sheet bundle is re-gripped, The sheet bundle is moved to the processing position. Therefore, the movement space from the gripping position (first position) before the gripping of the sheet bundle to the processing position can be minimized, and the operation space of the sheet gripping member 802 in the apparatus can be made more efficient. Can do. Thereby, it is possible to prevent the sheet gripping member 802 from interfering with other devices inside the apparatus, and it is also possible to prevent an increase in the size of the apparatus due to securing a moving space for the sheet gripping member 802.

  Further, as a further effect of performing this control, since the gripping position at the time of stacking the sheets and the gripping position at the time of moving the sheet bundle are different, the load on the sheet surface due to the sheet gripping can be distributed. As a result, it is possible to prevent image peeling and sheet damage due to concentration of the load on the sheet surface due to sheet gripping to a part, and to prevent deterioration of the quality of the bookbinding product.

  In addition, in order to prevent interference between the sheet gripping member and other devices in the apparatus, an operation of re-holding the sheet bundle is performed as shown in FIG. 9A. If the gripping operation is always performed, there is no need to perform the operation of gripping the sheet bundle again. However, if the sheet gripping operation is performed at a position after the re-gripping operation from the beginning, the movement amount for opening the sheet gripping member increases in the gripping operation for each sheet as shown in FIG. 9C. . As a result, the gripping operation for each sheet takes time, which leads to a decrease in productivity. As shown in FIG. 9B, when the gripping operation for each sheet is performed, as described above, the opening amount of the sheet gripping member for each sheet is small by gripping the rear end portion of the sheet. Since the operation time is shortened, a decrease in productivity can be minimized.

  When the movement of the sheet bundle to the center position (staple position) is completed in step S1010, the saddle stitching operation by the stapler 820 is performed in step S1011 (see FIG. 8B). When the saddle stitching is completed, an operation of moving the sheet bundle to the nip position (folding processing position) is performed in step S1012. That is, the positioning motor M4 and the sheet gripping member moving motor M3 are driven, and the sheet bundle is moved by the positioning member 805 and the sheet gripping member 802 until the binding processing position of the sheet bundle reaches the folding processing position of the pair of folding rollers 810a and 810b. (See FIG. 8C). When the movement is completed, in step S1013, the sheet gripping motor M2 is driven to rotate the sheet gripping member 802 to the retracted posture, and the gripping of the sheet bundle is released. Next, in step S1014, the folding roller pair 810a, 810b is driven to rotate by the folding motor M5, and at the same time, the projecting member 830 is projected by the thrust motor M6 to push the sheet bundle to the folding roller pair 810a, 810b (FIG. 8). (See (d)). The extruded sheet bundle is conveyed downstream while being folded into the folding roller pairs 810a and 810b, and discharged to the bookbinding tray 850 by the folding and conveying roller pairs 811a and 811b and the folding and conveying roller pairs 812a and 812b (step S1015). ).

  In the above-described embodiment, the stapler (binding means) 820, the folding roller pair 810, and the protruding member 830 are exemplified as the processing means for processing the sheet bundle at a predetermined processing position. However, the present invention is not limited to this. It is not a thing. Both the binding means and the folding means as the processing means perform saddle stitching in which the central portion in the sheet conveyance direction is bound at a predetermined binding processing position, or center folding in which the central portion is folded in two at a predetermined folding processing position. Although illustrated, this invention is not limited to this. The position where the sheet bundle is processed is not limited to the central portion in the sheet conveyance direction described above, and may be set as appropriate. Further, in the above-described embodiment, the position where the binding processing position by the binding unit and the folding processing position by the folding unit are different in the sheet conveyance direction is exemplified, but the same processing position may be used. In this case, the time required for sheet processing is further reduced.

  In the above-described embodiment, the sheet processing apparatus that can be appropriately attached to the main body of the image forming apparatus has been exemplified. However, the present invention is not limited to this. For example, the image forming apparatus may be a sheet processing apparatus that is integrally provided, and the same effects can be obtained by applying the present invention to the sheet processing apparatus.

M1, M2, M3, M4, M5, M6... Motor 10... Image forming apparatus main body 111... Photoconductor drum 113... Development device 400 ... Operation display device 500 ... Finisher 523 ... Bookbinding pass 530 ... Punch units 700, 701. 800 ... saddle stitch bookbinding portion 801 ... conveying roller pair 802 ... sheet gripping member 803 ... storage guide 805 ... sheet positioning member 810a, 810b ... folding roller pair 820a ... stapler 820b ... anvil 830 ... ejection member 850 ... bookbinding tray 900 ... CPU circuit Unit 922 ... Image signal control unit 951 ... Finisher control unit

Claims (5)

Sheet stacking means for sequentially stacking conveyed sheets; and
Processing means for selectively performing processing at a predetermined processing position on a sheet bundle composed of a plurality of sheets stacked on the sheet stacking means;
A sheet gripping means for gripping an end of a sheet bundle stacked on the sheet stacking means and moving the sheet bundle to the processing position;
Have
Before moving the sheet bundle to the processing position, the sheet gripping unit once releases the holding of the sheet bundle at the first position where the end of the sheet bundle has been gripped so far, and moves to the processing position. The direction is opposite to the direction in which the sheet bundle is moved, and the sheet bundle is moved from the first position to a second position closer to the end of the sheet bundle, and the sheet bundle is gripped again at the second position. Then, the sheet processing apparatus moves the sheet bundle to the processing position.   The sheet gripping means holds the end of the sheet against the sheet stacking means every time a sheet is stacked on the sheet stacking means at the first position that does not hinder the conveyance of the sheet to the sheet stacking means. The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus grips the sheet. Apart from the sheet gripping means, it has a receiving means for moving a sheet bundle made up of a plurality of sheets stacked on the sheet stacking means to the processing position,
The receiving means moves to the position of the other end according to the length of the sheet in the conveying direction with reference to the position of the sheet holding means for holding one end of the sheet bundle, and the sheet stacking means The sheet processing apparatus according to claim 1, wherein the other end portion of the sheet conveyed to the sheet is received and held, and the held sheet bundle is moved to the processing position.   The movement operation of the sheet gripping means before moving the sheet bundle to the processing position is performed when the length in the sheet conveyance direction exceeds a predetermined length, or when the basis weight of the sheet is less than a predetermined value. 4. The method according to claim 1, wherein the sheet is not carried out when the length of the sheet in the conveyance direction is equal to or less than a predetermined length even if the basis weight of the sheet is less than the predetermined value. The sheet processing apparatus according to the description.   The sheet processing apparatus according to claim 1, wherein an image forming unit that forms an image on a sheet, and a sheet processing apparatus that selectively performs processing on a sheet bundle including a plurality of sheets on which images are formed. And an image forming apparatus.

Images