JP6314887B2 - Sheet post-processing apparatus and image forming system including the same - Google Patents

Description

  The present invention relates to a sheet post-processing apparatus that performs post-processing such as punch hole forming processing and binding processing on a sheet of paper or the like on which an image is formed by an image forming apparatus such as a copying machine, a facsimile, or a printer, and an image forming system including the same. About.

  2. Description of the Related Art Conventionally, a plurality of sheets (sheets) on which images are formed by an image forming apparatus such as a copying machine or a printer are stacked, and a binding process for binding the stacked sheet bundles together with staples, and punch holes in a punch hole forming apparatus. Paper post-processing devices capable of executing punch hole forming processing for punching (punching) are used.

  In such a sheet post-processing apparatus, the punch hole forming apparatus forms a plurality of punch holes not along the sheet conveying direction but along the edge in the direction orthogonal to the conveying direction. The reason for this is that when punch holes are formed along the edge in the paper transport direction, it is necessary to temporarily stop the paper, and there is a concern about a decrease in productivity (processing efficiency), and the A3 size. This is because there is no demand for forming punch holes along the edges in the paper transport direction because A4 size paper can be transported horizontally (transverse paper) in an image forming apparatus capable of printing on paper.

  However, in recent years, with the demand for space-saving image forming apparatuses, image forming apparatuses that carry A4 size paper vertically (longitudinal paper) have been put on the market. For this reason, there is a demand for forming punch holes along the edges in the sheet conveyance direction.

  As a method of forming a plurality of punch holes in the paper conveyance direction, for example, in Patent Document 1, when performing folding processing on a punched sheet, the punching of the sheet is overlapped at two places. A post-processing device for changing the drilling position relative to the centerline is disclosed. Further, in Patent Document 2, in a sheet post-processing apparatus that forms punch holes without stopping a sheet being conveyed, a punching device and an end detection unit that detects a side edge of the sheet are orthogonal to the conveying direction. A sheet processing apparatus that can move in the direction and forms punch holes at positions corresponding to the size of the conveyed sheet is disclosed.

JP 2002-68777 A JP 2000-21802 A

  By the way, in the binding process for binding a sheet bundle with staples, when the binding process is performed at a plurality of locations at the rear end of the sheet bundle in the conveyance direction (hereinafter referred to as saddle stitching process), the sheet bundle is moved from the reference stacking position of the processing tray. Staples and discharges without any problems. On the other hand, when binding processing is performed at one position on the near side or the back side of the rear end in the transport direction of the sheet bundle (hereinafter referred to as the end binding process), the sheet bundle is moved from the reference stacking position of the processing tray to the near side or the far side. After shifting and stapling, the sheet is discharged as it is.

  When performing the above edge binding process on a sheet bundle in which punch holes are formed along the edge in the sheet conveyance direction, depending on the sheet size, the sheet shift amount (about 10 to 20 mm) and the sheet conveyance direction end Since the punch hole formation position (about 10 to 15 mm) from the edge is close, the leading edge of the succeeding paper may be caught in the punch hole of the already discharged paper. As a result, there has been a problem that the paper discharged onto the discharge tray is pushed out and misalignment occurs.

  SUMMARY OF THE INVENTION In view of the above problems, the present invention, when shifting and ejecting a sheet having punch holes formed in the transport direction, pushes out the paper due to interference between the punch holes of the already ejected sheet and the leading edge of the subsequent sheet. Another object of the present invention is to provide a sheet post-processing apparatus that can prevent misalignment and an image forming system including the sheet post-processing apparatus.

  To achieve the above object, the present invention is a sheet post-processing apparatus including a punch hole forming device, a processing tray, a stapler, and a discharge tray. The punch hole forming device forms punch holes along the side edge of the sheet parallel to the sheet conveying direction. The processing tray is disposed on the downstream side in the sheet conveying direction of the punch hole forming apparatus, and receives and stacks a predetermined number of sheets. The stapler performs a binding process on a predetermined position of the sheet bundle stacked on the processing tray. The discharge tray is disposed downstream of the processing tray in the sheet conveyance direction, and the sheets stacked on the processing tray are discharged. The stapler moves the sheet bundle from the reference position to the edge binding position shifted from the reference position in the sheet width direction. Thus, it is possible to execute an end binding process in which a binding process is performed at one end in the conveyance direction and at one end in the sheet width direction. When punch holes are formed in the sheet bundle to be subjected to the end binding process, the sheet bundle subjected to the binding process at the end binding position is returned to the reference position and then discharged from the processing tray to the discharge tray.

  According to the first configuration of the present invention, when the edge binding process is performed on the sheet in which the punch hole is formed, the sheet bundle subjected to the binding process at the end binding position is discharged after being returned to the reference position. The corner of the subsequent processed sheet is not caught in the punched hole of the already discharged sheet. Therefore, the sheet discharged onto the discharge tray is not pushed out in the discharge direction by the subsequent sheet, and it is possible to effectively prevent sheet misalignment and dropping from the discharge tray.

Schematic showing the internal configuration of the image forming apparatus 100 and the sheet post-processing apparatus 20 of the present invention. FIG. 2 is a partially enlarged view of the periphery of a processing tray 30 in the paper post-processing apparatus 20 in FIG. 1 and shows a state in which discharge rollers 29a are arranged at a separation position. FIG. 2 is a partially enlarged view around a processing tray 30 in the paper post-processing apparatus 20 in FIG. 1 and shows a state in which a discharge roller 29a is arranged at a contact position. A block diagram showing a control path of an image forming system including the image forming apparatus 100 and the sheet post-processing apparatus 20 The flowchart which shows an example of punch hole formation processing and binding processing control in the paper finishing device 20 of the present invention. A plan view of a sheet post-processing apparatus 20 that performs edge binding to a sheet bundle in which punch holes are formed along an edge on the front side of the apparatus. A plan view of a sheet post-processing apparatus 20 that performs edge binding on a sheet bundle in which punch holes are not formed. A plan view of a sheet post-processing apparatus 20 that performs saddle stitching on a sheet bundle in which punch holes are formed along the front edge of the apparatus. The flowchart which shows the other example of punch hole formation processing in the paper post-processing apparatus 20 of this invention, and binding processing control.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, an image forming system including the image forming apparatus 100 and the sheet post-processing apparatus 20 of the present invention will be described with reference to FIG. FIG. 1 is a schematic diagram showing internal configurations of an image forming apparatus 100 and a sheet post-processing apparatus 20 according to the present invention. In the present exemplary embodiment, a multifunction peripheral is illustrated as an example of the image forming apparatus 100. However, the paper post-processing apparatus 20 of the present invention may be applied to a printer other than a digital multifunction peripheral, such as a laser printer, an inkjet printer, or a facsimile apparatus. Can be similarly connected.

  As shown in FIG. 1, the image forming apparatus 100 is a so-called in-cylinder discharge type digital multi-function peripheral, and mainly includes a main body housing 2 a and an upper housing 2 b disposed on the main body housing 2 a. Yes. The upper housing 2b is provided with various mechanisms, which will be described later, for reading an image of an original as an electrical signal, and an original conveying device 3 is attached to the upper portion of the upper housing 2b. On the other hand, the main body housing 2a is provided with various mechanisms, which will be described later, for transferring an image to a sheet based on an electric signal of the read original image. A sheet post-processing device 20 is attached to the left side of the main body housing 2a. ing.

  In the present embodiment, the main body housing 2a includes a lower housing 2aa and a connection housing 2ab that is positioned along the right side and is connected to the upper housing 2b above the lower housing 2aa. A paper feed unit 4, an image forming unit 6 for forming a toner image on the paper P, a fixing device 7 for fixing the toner image on the paper, and the like are provided. A paper discharge portion (discharge portion) 18 for conveying the paper P and discharging it from the main body housing 20 is provided.

  A cylinder discharge space 16 that is largely open toward the left side and the front is formed on the left side of the connecting housing 2ab immediately below the upper housing 2b. A relay unit 19 is provided that receives and stacks the paper P discharged from the left side surface of the connecting housing 2ab and enables the paper P to be conveyed to the paper post-processing device 20 when a predetermined post-processing is performed. Yes.

  In the main body housing 2 a, the sheet feeding unit 4 disposed at the lower part, the sheet conveying unit 5 disposed on the side and above the sheet feeding unit 4, and the sheet feeding unit 4 are disposed above the sheet feeding unit 4. An image forming unit 6 and a fixing unit 7 disposed on the downstream side of the image forming unit 6 in the sheet conveying direction (the right side in FIG. 2) are provided.

  The paper feed unit 4 is provided with a plurality of paper feed cassettes 4a provided with separating and feeding means such as paper feed rollers on the downstream side in the paper transport direction, and the paper P placed in the paper feed cassette 4a. Are fed one by one from the uppermost sheet P to the sheet transport unit 5 by the rotation operation of the sheet feeding roller. The paper transport unit 5 transports the paper P fed from the paper feed unit 4 to the image forming unit 6 by each transport roller pair 5a.

  The image forming unit 6 and the fixing unit 7 are elongated in the width direction (the front-rear direction and the direction orthogonal to the paper surface of FIG. 1) perpendicular to the paper conveyance direction inside the apparatus main body 100, and in the upper part in the lower housing 2aa. The image forming unit 6 and the fixing unit 7 are arranged in this order from the left side in FIG. 1 along the conveyance direction of the paper P (from left to right).

  The image forming unit 6 forms a predetermined toner image on the paper P by an electrophotographic process. The image forming unit 6 is a photosensitive drum 9 that is an image bearing member that is rotatably supported. A charging device 11, an exposure device 12, a developing device 13, a transfer device 14, a cleaning device 15, and a static elimination device (not shown) are provided around the periphery along the rotation direction. The fixing unit 7 heats and presses the sheet P on which the toner image has been transferred in the image forming unit 6 between a pair of fixing rollers 7a including a heating roller and a pressure roller, thereby forming an unfixed toner image. It is fixed on the paper P.

  An image reading unit 8 is provided in the upper housing 2b. The image reading unit 8 reads image information of a document, and when reading each document by hand, the document conveying device 3 is opened and a contact glass 8a provided on the upper surface of the upper housing 2b. When a document is placed on the document stack and the document bundle is automatically read one by one, the document bundle is placed on the paper feed tray 3a of the document transport device 3 in a closed state. When the original bundle is placed on the paper feed tray 3a, the originals from the original bundle are automatically and sequentially sent onto the contact glass 8a one by one. In either case, the original positioned on the contact glass 8a is irradiated with light from an exposure lamp (not shown), and the reflected light is transmitted as image light to an optical system (not shown) such as a reflecting mirror and an imaging lens. To the photoelectric conversion unit (CCD).

  Hereinafter, a basic operation of the image forming apparatus 100 configured as described above will be described. First, the surface of the photosensitive drum 9 that rotates counterclockwise in FIG. 1 is uniformly charged by the charging device 11. Subsequently, based on the image information read by the image reading unit 8, a laser beam from the exposure device 12 (laser device or the like) is applied to the peripheral surface of the photosensitive drum 9, and thereby the surface of the photosensitive drum 9 is statically irradiated. An electrostatic latent image is formed. By supplying toner as a developer from the developing device 13 to the electrostatic latent image, a toner image is formed.

  Next, the paper P from the paper supply unit 4 passes through the paper transport path 5 and is transported toward the photosensitive drum 9 on which the toner image is formed at a predetermined timing. Here, the transfer device 14 including a transfer roller or the like. Thus, the toner image on the surface of the photosensitive drum 9 is transferred to the paper P. The paper P on which the toner image is transferred is separated from the photosensitive drum 9 and conveyed toward the fixing unit 7. The paper P is heated and pressurized when passing through the fixing roller pair 7a to fix the toner image.

  After the toner image has been transferred onto the paper P, the photosensitive drum 9 has the residual toner remaining on the peripheral surface removed by the cleaning device 15 and then the residual charge is removed by a static eliminator (not shown). A static elimination process is performed. Thereafter, the peripheral surface is charged again by the charging device 11, and image formation is performed in the same manner.

  The sheet P that has passed through the fixing unit 7 is conveyed in the connection housing 2ab along the sheet conveying path 5 as it is vertically upward. The upper part of the paper conveyance path 5 branches into two upper and lower conveyance paths toward the left in the connecting housing 2ab, and the conveyance direction of the paper P can be switched by the switching claw 17 arranged at the branching portion. ing.

  A paper discharge portion 18 is provided in the connection housing 2ab. The paper discharge unit 18 includes an upper discharge roller pair 18a and a lower discharge roller pair 18b disposed immediately below the upper discharge roller pair 18a, and the paper P conveyed through the paper conveyance path 5 is a switching claw. 17 is guided to an upper conveyance path or a lower conveyance path.

  The paper P guided to the upper conveyance path by the switching claw 17 is discharged leftward from the upper discharge roller pair 18a, and the paper P guided to the lower conveyance path by the switching claw 17 is discharged by the lower discharge roller pair 18b. It is discharged to the left. The switching claw 17 is configured to switch the guide direction by the control unit 70 (see FIG. 4).

  The relay unit 19 is detachably attached to the bottom surface 16a of the in-cylinder discharge space 16, and the in-cylinder discharge space 16 is provided with a detection sensor (not shown) that detects the attachment of the relay unit 19. . The detection sensor is composed of a PI sensor or the like, and transmits the detection result to the control unit 70.

  Further, the bottom surface 16a is formed with an inclined surface that is inclined upward toward the downstream side in the sheet discharge direction (left side in FIG. 1), and when the relay unit 19 is separated from the in-body discharge space 16, The bottom surface 16a is used as a paper discharge tray. In this case, the detection sensor detects that the relay unit 19 is not attached, and when the detection result is transmitted to the control unit 70, the switching claw 17 guides the paper P to the upper discharge roller pair 18a. The paper P discharged from the upper discharge roller pair 18a is discharged onto the bottom surface 16a.

  On the other hand, when the detection sensor detects that the relay unit 19 is installed in the in-body discharge space 16 and the detection result is transmitted to the control unit 70, the switching claw 17 causes the paper P to be transferred to the lower discharge roller pair 18b. invite. Then, the paper P discharged from the lower discharge roller pair 18 b is carried into the relay unit 19. The paper P carried into the relay unit 19 passes through the relay unit 19 and is carried into the paper post-processing device 20.

  The detection result can be displayed on the operation unit 80 (see FIG. 4), and the user can switch the guide direction of the paper P on the operation panel. Further, the upper surface portion of the relay unit 19 constitutes a paper discharge tray on which the paper P discharged from the upper discharge roller pair 18a is placed.

  Inside the paper post-processing device 20, a punch hole forming device 21 that forms punch holes on the loaded paper P, a processing tray 30 that stacks a plurality of the loaded paper P, and a processing tray 30. A stapler 40 is provided for binding a bundle of sheets stacked thereon with staples. A discharge tray 50 that can be raised and lowered to a position suitable for discharging the paper P is provided on the side surface of the paper post-processing device 20.

  The punch hole forming device 21 is disposed on the upper portion of the paper post-processing device 20 and forms a plurality of punch holes along one side edge (the front side or the rear side) parallel to the transport direction of the paper P. . At a substantially central portion in the direction (perpendicular to the paper surface in FIG. 1) upstream of the punch hole forming device 21 and perpendicular to the paper transport direction, a pair of paper carry-in rollers in the relay unit 19 is placed in the paper post-processing device 20. A carry-in detection sensor (not shown) for detecting the leading edge of the paper P to be carried in is arranged.

  The control unit 70 controls the driving of the paper carry-in roller pair in the relay unit 19 based on the detection timing of the leading edge of the paper P by the carry-in detection sensor, so that the conveyance direction of the paper P conveyed to the punch hole forming device 21 is controlled. Adjust the punch hole formation position. Specifically, a conveyance direction pulse adjustment value for adding or subtracting a reference conveyance pulse value from the detection of the leading or trailing edge of the paper P by the carry-in detection sensor to the stop of the paper carry-in roller pair is set.

  2 and 3 are partial cross-sectional views around the processing tray 30 in the sheet post-processing apparatus 20. A first discharge roller pair 27 is disposed on the downstream side of the punch hole forming device 21 (see FIG. 1) with respect to the paper transport direction. An actuator type paper detection sensor 28 that detects the passage of the paper P is disposed upstream of the first discharge roller pair 27.

  Further, below the first discharge roller pair 27, a processing tray 30 on which a predetermined number of sheets P conveyed by the first discharge roller pair 27 are aligned and stacked, and a bundle of sheets P stacked on the processing tray 30 ( A stapler 40 (see FIG. 1) that performs a binding process is provided on the sheet bundle.

  A second discharge roller pair 29 that discharges the sheet bundle from the processing tray 30 to the discharge tray 50 is disposed on the downstream side of the processing tray 30 with respect to the sheet conveyance direction. The second discharge roller pair 29 includes a rubber discharge roller 29a that can be rotated forward and backward by a drive motor (not shown), and a resin discharge roller 29b that rotates following the discharge roller 29a. . The discharge roller 29a is supported by a roller holder 31 that can swing up and down about the rotation shaft 31a.

  At the upper side of the processing tray 30 and downstream of the first discharge roller pair 27 (left side in FIG. 2), the paper P carried by the first discharge roller pair 27 is struck in the direction of the processing tray 30 and along the tray surface. A hitting member 33 is provided for the purpose. The processing tray 30 is provided so as to incline downward toward the rear end side (right side in FIG. 2) of the stacked paper P, and the second discharge roller pair 29 rotates in reverse to cause the paper P to move to the rear end. The paper P is drawn onto the processing tray 30 from the side, and the rear end of the paper P comes into contact with the abutting portion 30a. As a result, the sheets are stacked on the processing tray 30 with the rear ends thereof aligned. Further, the processing tray 30 is provided with a pair of side edge alignment cursors 60 for aligning the sheet bundle loaded on the processing tray 30 in the width direction (direction perpendicular to the paper surface of FIG. 2).

  The stapler 40 can be moved in the paper width direction perpendicular to the transport direction by a moving mechanism (not shown), and moves to a predetermined position along the lower end of the processing tray 30 according to the content of the binding process.

  Next, the operation of the sheet post-processing apparatus 20 will be described. When a sheet P (indicated by a broken line in FIGS. 2 and 3) on which image forming processing has been performed by the image forming apparatus 100 is carried in, if punch hole formation is instructed, the sheet P is conveyed by the punch hole forming apparatus 21. When punch holes are formed at predetermined positions (for example, two locations along the side edge on the front side of the apparatus) of the sheet P to be printed, and punch hole formation is not instructed, the punch holes forming apparatus 21 is passed through.

  Then, the paper P is conveyed further downstream by the first discharge roller pair 27. At this time, as shown in FIG. 2, the roller holder 31 swings upward, and the discharge roller 29a is disposed at a position (retracted position) away from the discharge roller 29b. Therefore, the paper P conveyed by the first discharge roller pair 27 protrudes to the discharge tray 50 through the gap between the discharge roller 29a and the discharge roller 29b.

  At the timing when the rear end of the sheet P passes through the first discharge roller pair 27, the roller holder 31 is swung downward and the discharge roller 29a is disposed at a position (contact position) where the discharge roller 29a contacts the discharge roller 29b. Thereafter, the tapping member 33 is driven to cause the paper P to follow the processing tray 30. In this state, by rotating the discharge roller 29a in the reverse direction (counterclockwise direction in FIG. 3), the paper P is drawn along the processing tray 30, and the trailing edge is aligned by the abutting portion 30a. The abutting portion 30a is not continuously formed over the entire area in the paper width direction, but is partially formed with a notch. At this time, the upper part of the paper P is nipped by the second discharge roller pair 29, and the front end of the paper P protrudes from the second discharge roller pair 29 onto the discharge tray 50. When the paper P is pulled along the processing tray 30, the paper P is nipped in a state where the discharge roller 29a is pressed against the discharge roller 29b only by its own weight so that the paper P is not pulled more than necessary. To do.

  When the acceptance of the paper P for one bundle is completed, the stapler 40 is moved to the notch position of the abutting portion 30a to insert the rear end of the paper bundle into the staple portion 40a, and the staple portion 40a binds the paper bundle. Processing is performed. After the sheet bundle is bound by the staple unit 40a, the sheet bundle is conveyed upward along the processing tray 30 by rotating the second discharge roller pair 29 in the normal direction (in the direction of the arrow in FIG. 3), and the discharge tray 50 Discharged to the top. When the sheet bundle is discharged to the discharge tray 50, not only the weight of the roller holder 31 but also the roller holder 31 is urged downward by a biasing member such as a spring so that the discharge roller 29a is pressed against the discharge roller 29b. As a result, the sheet bundle is nipped with a stronger force than when the sheet P is pulled in, so that the sheet bundle can be reliably discharged to the discharge tray 50.

  When the shift discharge is set, when the second discharge roller pair 29 is driven to discharge the sheet bundle to the discharge tray 50, the roller holder 31 is first moved to the retracted position. After that, the side edge alignment cursor 60 is arranged at a position (shift position) shifted by a predetermined amount from the position where the paper P is received (reference position) or from the reference position in a direction orthogonal to the discharge direction (paper width direction). Then, the roller holder 31 is moved to the contact position to discharge the paper. As a result, the sheet bundle is alternately discharged to the reference discharge position on the discharge tray 50 and the shift discharge position shifted by a predetermined amount in the direction orthogonal to the discharge direction (paper width direction) from the reference position. When being discharged onto the tray 50 (see FIG. 1), they are alternately stacked in the paper width direction and sorted.

  FIG. 4 is a block diagram illustrating a control path of the image forming system including the image forming apparatus 100 and the sheet post-processing apparatus 20. Note that the control unit 70 itself is complicated because various controls of each part of the apparatus are performed in using the image forming system. Therefore, in FIG. 4, portions of the control unit 70 and the sheet post-processing device 20 that are necessary for carrying out the present invention are mainly described. Here, the entire image forming system is controlled using the control unit 70 provided in the image forming apparatus 100, but a control unit may be provided in the sheet post-processing apparatus 20.

  The control unit 70 includes a central processing unit (CPU) 71 as a central processing unit, a read only memory (ROM) 72 that is a read-only storage unit, a random access memory (RAM) 73 that is a readable / writable storage unit, And at least a temporary storage unit 74 for storing image data and the like, a counter 75, and a plurality of (here, two) I / Fs (interfaces) 76. A control signal is transmitted to each device in the processing device 20 and an input signal from the operation unit 80 is received.

  The ROM 72 stores data that cannot be changed, such as system control programs and numerical values necessary for control. The RAM 73 stores necessary data generated during system control, data temporarily required for control, and the like. Further, the ROM 72 (or RAM 73) stores a reference conveyance pulse value transmitted to a roller drive motor (not shown) from the detection of the leading edge of the paper P by the carry-in detection sensor (not shown) until the paper carry-in roller is stopped. Is also remembered.

  The counter 75 counts the number of sheets printed on the image forming apparatus 100 and counts the number of sheets P carried into the sheet post-processing apparatus 20 from the image forming apparatus 100 based on a detection signal of the carry-in detection sensor. Alternatively, the number of sheets of paper P carried on the processing tray 30 is counted based on a detection signal of the paper detection sensor 28 disposed on the upstream side of the processing tray 30 with respect to the paper transport direction. Note that the number of times may be stored in the RAM 73, for example, without providing the counter 75 separately.

  In addition, the control unit 70 transmits a control signal from the CPU 71 to the respective units and apparatuses in the system including the image forming apparatus 100 and the sheet post-processing apparatus 20 through the I / F 76. In addition, a signal indicating the state and an input signal are transmitted from each part or device to the CPU 71 through the I / F 76. Examples of each part and device controlled by the control unit 70 include, for example, a sheet conveying unit 5, an image forming unit 6, a fixing device 7 (see FIG. 1) of the image forming apparatus 100, and punch hole formation of the sheet post-processing apparatus 20. Examples of the apparatus 21 include a first discharge roller pair 27, a second discharge roller pair 29, a processing tray 30, a stapler 40, and a side edge alignment cursor 60.

  The operation unit 80 is provided with a liquid crystal display unit 81, LEDs 82 indicating various states, and a numeric keypad 83. The user operates the operation unit 80 to input an instruction, whereby the image forming apparatus 100, paper post-processing is performed. Various settings of the apparatus 20 are performed, and various functions such as an image forming function and a post-processing function are executed. The liquid crystal display unit 81 displays the system status, displays the image formation status and the number of prints, and can be used as a touch panel for various settings such as functions such as double-sided printing and black-and-white reversal, magnification setting, and density setting. . The numeric keypad 83 is used for setting the number of prints and for inputting a transmission destination FAX number when the image forming apparatus 100 has a FAX function.

  In addition, the operation unit 80 includes a start button for instructing the user to start image formation, a stop / clear button used when the image formation is stopped, and other settings for the system to default states. A reset button or the like is provided.

  FIG. 5 is a flowchart showing an example of punch hole formation processing and shift discharge control in the paper post-processing apparatus 20 of the present invention. The punch hole forming process and the binding process procedure will be described along the steps of FIG. 5 with reference to FIGS.

  When the user inputs a print instruction from the operation unit 80 (see FIG. 4) or the personal computer setting screen (operation terminal) (step S1), the control unit 70 determines whether punch hole formation processing is set. (Step S2). If the punch hole forming process is set (YES in step S2), the punch hole forming device 21 forms a punch hole at a predetermined position along one side edge in a direction parallel to the transport direction. (Step S3). As a method for setting the punch hole formation position, for example, there is a method of transmitting the punch hole position information calculated from the paper size information input from the operation unit 80 or the personal computer setting screen to the control unit 70.

  Next, the control unit 70 determines whether or not the binding process is set (step S4). If the binding process is set (YES in step S4), it is determined whether or not the set binding process is an end binding process (step S5). If the edge binding process is set (YES in step S5), a predetermined number of sheets P are stacked on the reference position of the processing tray 30, and then the stacked sheet bundle is orthogonal to the transport direction (here, the front side). ) To the end binding position shifted by a predetermined amount (step S6). Thereafter, the end binding process is executed by the stapler 40 that has been moved to the end binding position in advance (step S7).

  Next, the control unit 70 determines whether or not punch holes are formed in the sheet bundle that has been subjected to the edge binding process (step S8). If a punch hole is formed (YES in step S8), the sheet bundle on the processing tray 30 is returned from the end binding position to the reference position (step S9). Then, the sheet bundle is conveyed upward along the processing tray 30 by the second discharge roller pair 29, and as shown in FIG. 6, a straight line O is defined with reference to a straight line O passing through the center in the direction orthogonal to the sheet conveying direction. Is discharged to a reference discharge position P1 that overlaps the center of the discharge tray 50 in the width direction (step S10).

  On the other hand, if no punch hole is formed in the sheet bundle (NO in step S8), the sheet bundle on the processing tray 30 is conveyed upward along the processing tray 30 from the edge binding position, as shown in FIG. Then, the sheet bundle is discharged from the reference discharge position P1 to the end binding discharge position P2 shifted by a predetermined amount in the paper width direction (front side here) (step S10).

  If the set binding process is not the edge binding process (NO in step S5), the saddle stitch process is performed on the sheet bundle stacked at the reference position of the processing tray 30 (step S11). Then, the sheet bundle on the processing tray 30 is conveyed upward along the processing tray 30 and discharged to the reference discharge position P1 on the discharge tray 50 as shown in FIG. 8 (step S10).

  If the binding process is not set (NO in step S4), a predetermined number of sheets P are stacked on the reference position of the processing tray 30, and then discharged to the reference discharge position P1 on the discharge tray 50 (step S10). ). Thereafter, it is determined whether or not the predetermined number of prints has been completed (step S12). If printing has been completed, the process is terminated. If printing continues, the process returns to step S2, and the same processing is repeated thereafter (steps S2 to S12).

  By performing the above-described control, when the edge binding process is performed on the sheet bundle in which punch holes are formed, the sheet bundle after the binding process is returned from the end binding position on the processing tray 30 to the reference position. The paper is discharged to the reference discharge position P1 of the discharge tray 50. Therefore, as in the case where the edge binding process is not performed on the subsequent sheet bundle (when the saddle stitching process is performed), the corner portion of the subsequent sheet bundle is caught in the punch hole of the sheet bundle already discharged to the reference discharge position P1. Absent. Therefore, the sheet bundle discharged onto the discharge tray 50 is not pushed out in the discharge direction by the subsequent sheet bundle, and it is possible to effectively prevent the sheet bundle from being misaligned or dropped from the discharge tray 50.

  On the other hand, when the edge binding process is performed on a sheet bundle in which punch holes are not formed, the sheet bundle after the binding process is directly discharged from the end binding position on the processing tray 30 to the end binding discharge position P2. Therefore, the step of returning the sheet bundle after the binding processing on the processing tray 30 from the end binding position to the reference position can be omitted, and the processing efficiency is improved.

  Further, the shift amount when shifting the sheet bundle from the reference position to the end binding position differs depending on the sheet size. Therefore, as shown in FIG. 9, a sheet of a predetermined size in which the punch hole formation position when the sheet bundle is moved from the reference position to the end binding position and the side edge of the sheet bundle stacked at the reference position overlap. (Step S9), and only when the sheet is a predetermined size (YES in step S9), after returning the sheet bundle subjected to the binding process at the end binding position to the reference position (step S10). It is also possible to discharge from the processing tray 30 to the reference discharge position of the discharge tray 50 (step S13).

  According to the control of FIG. 9, the sheet bundle is returned from the end binding position to the reference position only when the corner portion of the subsequent sheet bundle may be caught in the punch hole of the sheet bundle that has already been discharged to the end binding discharge position P2. A process is added. Therefore, it is possible to improve the processing efficiency of the sheet post-processing device 20 as much as possible by minimizing the step of returning the sheet bundle from the end binding position to the reference position.

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning of this invention. For example, in the above embodiment, the configuration in which the image forming apparatus 100 and the paper post-processing apparatus 20 are directly connected has been described as an example. However, a slip sheet is inserted between the image forming apparatus 100 and the paper post-processing apparatus 20. The present invention can also be applied to a configuration in which an insert device is mounted.

  In the above embodiment, the single stapler 40 is moved to perform the saddle stitching process and the end binding process. However, the saddle stitching stapler and the end stapler may be provided separately.

  The present invention is applicable to a sheet post-processing apparatus capable of forming punch holes along the sheet conveying direction. By using the present invention, when performing a binding process on a sheet in which a plurality of punch holes are formed in the conveyance direction, sheet post-processing that can prevent sheet extrusion and misalignment due to interference between the punch holes and the corners of the sheet An apparatus and an image forming system including the apparatus can be provided.

6 Image forming unit 8 Image reading unit 20 Paper post-processing device (sheet post-processing device)
DESCRIPTION OF SYMBOLS 21 Punch hole formation apparatus 27 1st discharge roller pair 28 Paper detection sensor 29 2nd discharge roller pair 30 Processing tray 40 Stapler 50 Discharge tray 60 Side edge alignment cursor 70 Control part 90 Punch hole 100 Image forming apparatus

Claims (5)

A punch hole forming device that forms punch holes along the side edge of the sheet parallel to the sheet conveying direction;
A processing tray disposed downstream of the punch hole forming device in the sheet conveying direction, for receiving and stacking a predetermined number of sheets;
A stapler for performing a binding process on a predetermined position of the sheet bundle stacked on the processing tray;
A discharge tray disposed on the downstream side of the processing tray in the sheet conveying direction and for discharging sheets stacked on the processing tray;
In a sheet post-processing apparatus comprising:
The stapler includes a saddle stitching process in which a binding process is performed at a plurality of positions at a rear end in a conveyance direction of a sheet bundle stacked at a reference position of the processing tray, and an end binding position in which the sheet bundle is shifted in the sheet width direction from the reference position. And end binding processing for performing binding processing at one end in the sheet width direction at the rear end in the conveyance direction,
When punch holes are formed in the sheet bundle to be subjected to the edge binding process, the sheet bundle subjected to the binding process at the edge binding position is returned to the reference position, and then discharged from the processing tray to the discharge tray .
A sheet post-processing apparatus , wherein when a punch hole is not formed in a sheet bundle to be subjected to the edge binding process, the sheet bundle subjected to the binding process is discharged from the edge binding position to the discharge tray . A punch hole forming device that forms punch holes along the side edge of the sheet parallel to the sheet conveying direction;
A processing tray disposed downstream of the punch hole forming device in the sheet conveying direction, for receiving and stacking a predetermined number of sheets;
A stapler for performing a binding process on a predetermined position of the sheet bundle stacked on the processing tray;
A discharge tray disposed on the downstream side of the processing tray in the sheet conveying direction and for discharging sheets stacked on the processing tray;
In a sheet post-processing apparatus comprising:
The stapler includes a saddle stitching process in which a binding process is performed at a plurality of positions at a rear end in a conveyance direction of a sheet bundle stacked at a reference position of the processing tray, and an end binding position in which the sheet bundle is shifted in the sheet width direction from the reference position. And end binding processing for performing binding processing at one end in the sheet width direction at the rear end in the conveyance direction,
When punch holes are formed in the sheet bundle to be subjected to the edge binding process, the sheet bundle subjected to the binding process at the edge binding position is returned to the reference position, and then discharged from the processing tray to the discharge tray.
The binding is performed at the end binding position only when the punch hole formation position when the sheet bundle is shifted from the reference position to the end binding position and the side edge of the sheet bundle stacked at the reference position overlap. after returning the sheet bundle subjected to processing in said reference position, characterized and to Resid over preparative post-processing apparatus to be discharged from the processing tray to the output tray. When punch holes are formed in the sheet bundle to be subjected to the edge binding process, punch hole formation positions when the sheet bundle is shifted from the reference position to the edge binding position, and sheets stacked at the reference position The sheet bundle having been subjected to the binding process at the end binding position is returned to the reference position and then discharged from the processing tray to the discharge tray only when the side edge of the bundle overlaps. sheet post-processing apparatus according to 1.   4. The reference position according to claim 1, wherein the reference position is a position where a straight line passing through a center in a direction orthogonal to a sheet conveyance direction and a center in the width direction of the discharge tray overlap each other. Sheet post-processing device. A sheet post-processing apparatus according to any one of claims 1 to 4,
An image forming apparatus connected to the sheet post-processing apparatus to form an image on the sheet and to convey the sheet on which the image is formed to the sheet post-processing apparatus;
A control unit for controlling the sheet post-processing apparatus and the image forming apparatus;
An image forming system.

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