JP2007070119A - Sheet processing device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance productivity by shortening a time required for stitching processing of a bundle of sheets regardless of the number of portions for stitching processing without causing a large size of a device, complication of a device constitution and cost increase. <P>SOLUTION: A finisher 600 has a stapler 301 for clamping and stitching the bundle of sheets successively intruded and superposed between an upper jaw part 301U and a lower jaw part 301L constituting a stitching part; and an alignment means for aligning the sheets intruded between the stitching parts 301U, 301L. A clearance between the stitching parts 301U, 301L of the stapler 301 is held in a stand-by attitude at a first clearance distance L until the final sheet of the bundle of sheets intrudes between the stitching parts 301U, 301L and is changed to a second clearance distance M before starting stitching action smaller than the first clearance distance L until alignment action of the final sheet is completed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sheet processing apparatus capable of binding a plurality of portions of a sheet bundle and an image forming apparatus using the sheet processing apparatus.

  2. Description of the Related Art Conventionally, as a sheet processing apparatus used in an image forming apparatus, a sheet bundle that is stacked and aligned on an intermediate processing tray can be bound by sequentially moving a stapler to positions corresponding to a plurality of binding positions. There is.

  For example, when the binding process is performed on one sheet bundle on the intermediate processing tray at one corner of the sheet bundle corner, the stapler has a predetermined angle at a position corresponding to a predetermined sheet bundle corner which is a binding position. Waiting in an inclined state. Then, for the sheet bundle aligned on the intermediate processing tray, binding processing at one corner portion is performed by the stapler waiting at the corner binding position. In this way, a sheet bundle is created that has undergone binding processing at one corner.

Japanese Patent Laid-Open No. 2001-220055

  When performing the above-described sheet bundle binding process, buffering that can temporarily store the sheet so that a new sheet does not enter the processing tray during the processing on the processing tray. In many cases, the mechanism is provided in the upstream portion of the processing tray. However, in order to realize further high-speed processing, the image forming process for the sheet on the image forming apparatus main body side is temporarily stopped during the sheet bundle binding process in the sheet processing apparatus, and the binding process is completed. Therefore, the intermittent operation control of restarting the image forming process is unavoidable. Therefore, when the above-described sheet bundle binding process is performed, there is a problem in that productivity is reduced by the time required for the binding process.

  As a means for shortening the time required for the binding process, it is conceivable to increase the binding speed at the binding position of the stapler. However, in order to realize this, it is necessary to power up the drive motor related to the stapler binding. In this case, there may be problems such as an increase in cost due to power-up of the motor, an increase in size of the apparatus, and an increase in operating noise.

  In addition, as a technique for shortening the time required for the binding process, Japanese Patent Laid-Open No. 2001-220055 (hereinafter referred to as Patent Document 1) is disclosed. In the technique of Patent Document 1, when the stapler is moved, the sheet bundle is moved in a direction opposite to the moving direction of the stapler, thereby reducing the moving distance of the stapler itself and reducing the time required for the binding process. However, this configuration is effective in reducing the time required for the two-point binding process, but is not effective in reducing the time required for the one-point binding process.

  Accordingly, an object of the present invention is to reduce the time required for the sheet bundle binding process regardless of the number of locations of the binding process, without increasing the size of the apparatus, complicating the apparatus configuration, and increasing the cost. It is to improve.

  In order to achieve the above object, a typical configuration of the present invention includes a binding unit that sandwiches and stacks sheet bundles that are sequentially entered and stacked between a first binding unit and a second binding unit, and the first binding unit. A sheet processing apparatus comprising: an alignment unit configured to align a sheet that has entered between the first binding unit and the second binding unit; and a control unit that controls the binding unit, wherein the control unit includes: The gap between the first binding portion and the second binding portion of the binding means is made to wait at the first gap distance until the final sheet of the sheet bundle enters between the binding portions, and the final sheet Control is performed so as to change to a second frontage distance before starting the binding operation that is smaller than the first frontage distance before the alignment operation ends.

  According to the present invention, without increasing the size of the apparatus, complicating the apparatus configuration, and increasing the cost, the time required for the sheet bundle binding process can be shortened and the productivity can be reduced regardless of the number of places of the binding process. Can be improved.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic cross-sectional view of an image forming apparatus including a sheet processing apparatus according to an embodiment of the present invention.

  The image forming apparatus shown in FIG. 1 includes a monochrome / color image forming apparatus main body 100 and a finisher 600 as a sheet processing apparatus having a saddle stitching processing unit 200 and a side stitching processing unit 300. The image forming apparatus main body 100 includes an image reader 120 and a printer 110, and a document feeder 130 is attached to the image reader 120. The originals separated and fed one by one by the document feeder 130 are read by the image reader 120.

  The sheets selectively fed from the cassettes 107a to 107d in the image forming apparatus main body 100 are sent to the image forming unit. In the image forming means, yellow, magenta, cyan, and black toner images are formed on the photosensitive drums 101a to 101d, respectively. The toner images of four colors are sequentially transferred onto the sheet from the photosensitive drums 101a to 101d, and the toner images are fixed by the fixing device 111, and are discharged out of the apparatus main body. The sheet discharged from the image forming apparatus main body 100 is sent to the finisher 600.

  The finisher 600 can sequentially take in the sheets discharged from the image forming apparatus and selectively perform a predetermined process. In the finisher 600 according to the present embodiment, it is possible to perform a punching process that punches holes in the vicinity of the rear end of the captured sheet. In addition, it is possible to perform alignment processing that aligns and bundles a plurality of captured sheets into a single sheet bundle, and flat binding processing that binds the rear end of the bundled sheet bundle. Also, alignment processing for aligning a plurality of captured sheets and binding them into one sheet bundle, saddle stitching processing for binding the center of the bundled sheet bundle, and folding processing for folding the saddle-stitched sheet bundle into two are performed. it can. Although it is possible to perform sort processing for sorting and discharging sheet bundles and non-sort processing for discharging without sorting, detailed description is omitted here because it is a known technique.

  The finisher 600 has an inlet roller pair 602 for guiding the sheet discharged from the image forming apparatus main body 100 to the inside. A switching flapper 601 for guiding the sheet to the side stitch bookbinding path X or the saddle stitch bookbinding path Y is provided downstream of the entrance roller pair 602.

  First, the operation of the side stitching processing unit 300 will be briefly described. The sheet guided to the flat stitch binding path X is sent toward the buffer roller 605 via the conveyance roller pair 603. The conveyance roller pair 603 and the buffer roller 605 are configured to be able to rotate forward and backward.

  A punch unit 650 is provided between the conveying roller pair 603 and the buffer roller 605. The punch unit 650 operates as necessary, and punches near the rear end of the conveyed sheet.

  The buffer roller 605 is a roller capable of stacking and winding a predetermined number of sheets sent to the outer periphery thereof. The sheet wound around the buffer roller 605 is guided to the sample tray 621 side by the switching flapper 611 disposed downstream, or is guided to the intermediate tray (hereinafter referred to as processing tray) 330 side in the flat stitching processing unit 300. .

  The sheet guided to the sample tray 605 side is discharged and stacked on the sample tray 621 by the second discharge roller pair 609.

  The sheet guided to the processing tray 330 side is discharged and stacked on the processing tray 330 by the first discharge roller pair 320. The sheets stacked on the processing tray 330 are subjected to alignment processing, flat binding processing, and the like as necessary, and then discharged onto the stack tray 622 by the bundle discharge rollers 380a and 380b. In the binding process for binding sheets stacked on the processing tray 330, a stapler 301 as a binding unit is used, and the corner and back portions of the sheet bundle are bound. Note that a series of flat stitching processes by the stapler unit having the stapler 301 will be described in detail later.

  Next, the operation of the saddle stitching processing unit 200 will be briefly described. The sheet guided to the saddle stitch bookbinding path Y is stored in the storage guide 220 by the transport roller pair 213 and further transported until the leading end of the sheet comes into contact with the movable sheet positioning member. In addition, two pairs of staplers 218 are provided in the middle position of the storage guide 220, and the staplers 218 are configured to bind the center of the sheet bundle in cooperation with the anvil 219 opposed thereto.

  At the downstream position of the stapler 218, folding roller pairs 226a and 226b are provided. A protruding member 225 is provided at a position opposite to the folding roller pair 226. When the sheet bundle bound by the stapler 218 is folded, the sheet positioning member is lowered by a predetermined distance so that the binding position of the sheet bundle becomes the center position of the folding roller pair 226 after the binding process is completed. Next, by projecting the protruding member 225 toward the sheet bundle, the sheet bundle is pushed out between the pair of folding rollers 226, and the sheet bundle is folded into two by the folding roller pair 226 to form a saddle stitched bookbinding bundle. .

  Here, the configuration of a control unit that controls the entire image forming apparatus will be described with reference to FIG. FIG. 7 is a block diagram illustrating a configuration of a control unit that controls the entire image forming apparatus of FIG.

  As illustrated in FIG. 7, the CPU circuit unit 150 as a control unit includes a CPU 151, a ROM 152, and a RAM 153. The CPU circuit unit 150 then controls the document feeder control unit 155, the image reader control unit 156, the image signal control unit 157, the printer control unit 158, and the finisher control according to the program stored in the ROM 152 and the setting of the operation unit 154. The unit 159 and the external interface 160 are collectively controlled. The document feeder controller 155 controls the document feeder 130, the image reader controller 156 controls the image reader 120, the printer controller 158 controls the printer 110, and the finisher controller 159 controls the finisher 600. In the present exemplary embodiment, the finisher 600 is indirectly controlled by the CPU circuit unit 150 on the image forming apparatus main body side via the finisher control unit 159. However, the present invention is not limited to this. . For example, the finisher 600 may be controlled only by the finisher control unit 159 as a control unit, or the finisher 600 may be directly controlled by the CPU circuit unit 150 on the image forming apparatus main body side.

  The RAM 153 is used as an area for temporarily holding control data and a work area for computations associated with control. The external interface 160 is an interface from the computer 161 and develops print data into an image and outputs the image to the image signal control unit 157. The image read by the image sensor is output from the image reader control unit 156 to the image signal control unit 157, and the image output from the image signal control unit 157 to the printer control unit 158 is input to the exposure control unit.

  Next, the configuration and operation of the side stitching processing unit 300 in the finisher 600 will be described in detail. The side stitching processing unit 300 includes a stapler unit including a stapler 301 and a processing tray unit including a processing tray 330.

  First, the stapler unit of the side stitching processing unit 300 will be described with reference to FIGS. 2 is a top view of the stapler unit, and FIG. 3 is a front view of the stapler unit. explain.

  As shown in FIGS. 2 and 3, the stapler (binding means) 301 is fixed on a slide support 303. Rolling rollers 304 and 305 are engaged with the lower portion of the slide support 303, and the rolling rollers 304 and 305 are guided by guide rail grooves 307 on the staple moving table 306. As a result, the stapler 301 moves substantially in parallel along the trailing edge of the sheets stacked on the processing tray 330. As shown in FIG. 2, the stapler 301 is maintained in a posture inclined at a predetermined angle α with respect to the trailing edge of the sheet at the corners (positions A and D) of the sheet on the processing tray 330. Will be. In the present embodiment, the predetermined angle α is approximately 30 °. However, the angle α can be changed by changing the shape of the guide rail groove 307.

  The staple unit is provided with a position sensor (not shown) that detects the home position of the stapler 301. This position sensor is provided on the staple moving base 306. The stapler 301 is set at the home position in FIG. 2 corresponding to the front side of the apparatus, and stands by at this position A in a standby state such as when the apparatus is stopped. Note that the stapler 301 according to the present embodiment can move to the corners (positions A and D) and the backs (positions B and C) of the sheet and perform binding processing according to the setting.

  Next, a mechanism for moving the stapler 301 in the arrow Y direction will be described with reference to FIG. The moving mechanism of the stapler 201 includes a driving motor 310 that can rotate forward and backward, and a moving belt 308 that is stretched between belt pulleys 309 a and 309 b that are rotated by the driving motor 310. The moving belt 308 is engaged with a belt support portion 311 provided at a lower portion of the slide abutment 303. As a result, the moving belt 308 is rotated by forward / reverse rotation driving of the drive motor 310, and the stapler 301 moves together with the moving belt 308 in the arrow Y direction.

  Next, a processing tray unit including the processing tray 330 will be described with reference to FIGS.

  The processing tray unit includes a processing tray 330, a rear end stopper 331, left and right end alignment means 340 and 341, a swing guide 350, a drawing paddle 360, and a bundle discharge roller pair 380. As the aligning means for aligning the sheets, the trailing end stopper 331 and the pull-in paddle 360 function as aligning means for aligning in the sheet conveying direction, and the aligning means 340 and 341 at the left and right ends are aligned in the sheet width direction. It functions as a matching means for performing matching.

  The processing tray 330 is set to be inclined downward from the downstream side (left side in FIG. 3) in the sheet bundle discharge direction toward the upstream side (right side in FIG. 3). A rear end stopper 331 is disposed at the upstream end of the processing tray 330. In addition, right and left end alignment means 340 and 341 are arranged in the middle portion of the processing tray 330. A retractable paddle 360 and a swing guide 350 are disposed in the upper region of the processing tray 330.

  Note that the rear end stopper 331 has a contact support surface 331a that supports the rear end edge of the sheet P as shown in FIG. 3, and the lower end side of the processing tray 330 is centered on the support pin 331b and is in the arrow Z direction. It is configured to be swingable.

  In this embodiment, as shown in FIG. 2, the rear end stopper 331 is provided at four locations (331A, 331B, 331C, 331D in FIG. 2), and each is supported so as to be able to swing independently. Each of the rear end stoppers 331A to 331D functions at a position where the stapler 301 enters a clinch area (an area where the sheet bundle is sandwiched) at a predetermined binding position (A, B, C, D in FIG. 2). For this reason, if the trailing edge stopper at the binding position of the stapler 301 remains at the position where the trailing edge of the sheet abuts, the trailing edge stopper is sandwiched by the clinch of the stapler 301. Therefore, in order to prevent this, only the trailing edge stopper located at the binding position of the stapler 301 is avoided in the arrow Z direction, and the trailing edge of the sheet P entering the processing tray 330 with the remaining three trailing edge stoppers. I try to hit it. For example, in FIG. 2, when the stapler 301 performs the binding process at the position A, only the rear end stopper 331A takes a position avoiding the clinch region (in the arrow Z direction), and the remaining three rear end stoppers 331B, 331C, and 331D. The rear edge of the sheet P is abutted and supported.

  Then, the sheet P discharged from the first discharge roller pair 320 onto the processing tray 330 has its trailing edge on the abutting support surface 331a of the trailing edge stopper 331 due to its own weight and the action of the drawing paddle 360. It is hit. Further, the sheet P is aligned at the left and right ends (the end in the width direction orthogonal to the sheet conveying direction) by the alignment means 340 and 341 at the left and right ends. Thereby, the sheets stored on the processing tray 330 are sequentially aligned and bundled as one sheet bundle.

  Further, one lower discharge roller 380 a constituting the bundle discharge roller pair 380 is disposed at the downstream end of the processing tray 330. Further, at the front end portion of the lower surface of the swing guide 350, the other upper discharge port 1380b that is detachably contacted with the lower discharge roller 380a is disposed. Each of these discharge rollers 380a and 380b is configured to be rotated forward and backward by a drive motor.

  The swing guide 350 is driven and controlled to swing freely around the support rod 351, and the closed position in which the upper discharge roller 380b is in contact with the lower discharge roller 380a is the home position. When the sheet P is discharged onto the processing tray 330, the bundle discharge roller pair 380 is shifted to the open state. This open state is a state in which the upper discharge roller 380b is separated from the lower discharge roller 380a by swinging the swing guide 350 upward. When the sheet bundle that has been processed on the processing tray 330 is discharged onto the stack tray 622, the bundle discharge roller pair 380 is shifted to a closed state. The closed state is a state in which the sheet bundle is sandwiched between the upper discharge roller 380b and the lower discharge roller 380a by swinging the swing guide 350 downward. Alternatively, when there is no sheet bundle, the upper discharge roller 380b is in contact with the lower discharge roller 380a.

  Next, a series of flat stitching processing by the stapler unit of the flat stitching processing unit 300 will be described in detail.

  The stapler 301 waits in advance at a desired clinching position (any one of the binding positions A to D shown in FIG. 2) with respect to the sheet bundle according to the binding mode (in this embodiment, the one-position binding mode or the two-position binding mode). ing. The stapler 301 staples the sheet bundle when the discharge and alignment of the final sheet P of the bundle are completed. Note that the stapler unit according to the present embodiment corresponds to the binding mode (one-point binding mode in which binding processing is performed at one corner of the sheet bundle, and two-point binding mode in which binding processing is performed at two back portions of the sheet bundle). Although the binding process is possible, the following description exemplifies a one-point binding mode.

  Here, the configuration of the stapler 301 will be described. As shown in FIG. 3, the stapler 301 includes a moving-side upper jaw portion 301U as a first binding portion and a fixed-side lower jaw portion 301L as a second binding portion. The stapler 301 is bound with a sheet bundle sandwiched between the upper jaw portion 301U and the lower jaw portion 301L. Specifically, when the upper jaw 301U descends and clinch the sheet bundle together with the lower jaw 301L, the staple needle protruding from the lower jaw 301L penetrates the sheet bundle, and the end of the needle is bent inward by the upper jaw 301U. Then, the sheet bundle is stapled so as to hold the sheet bundle. After the clinching is completed, the upper jaw portion 301U rises again, and prepares for the next clinching operation in a state where the gap distance L with the lower jaw portion 301L is maintained.

  The gap distance L varies depending on conditions such as the number of sheets bundled, the bundle thickness, and the sheet curl amount (hereinafter referred to as binding conditions). In the present embodiment, the frontage distance L is determined according to the binding conditions such as the number of staple-bound sheets, the amount of sheet curl, and the air layer between sheets. Specifically, taking into account the staple binding sheet bundle = 100 sheets bundle, the sheet curl amount = 10 mm, the air layer between the sheets, and the like, the frontage distance L is set to 30 to 35 mm.

  Next, with reference to FIGS. 2, 5, and 6, processing when the one-position binding mode is selected in the above-described binding mode setting will be described.

  First, when the one-point binding mode is selected, the stapler 301 is moved to a predetermined binding position of the sheet bundle (in this embodiment, one of the positions A and D in FIG. 2) as shown in FIG. 6 (S101). ). Then, the sheets are discharged onto the processing tray 330 and are sequentially aligned (S102, S103). During this aligning operation, the stapler 301 stands by at the predetermined binding position (any one of positions A and D in FIG. 2). At this time, the stapler 301 stands by at the frontage distance (first frontage distance) L between the binding portions 301U and 301L. For this reason, when aligning the sheets discharged onto the processing tray 330, for example, even if the sheet end is curled, the sheet end is not caught on the upper jaw 301U of the stapler 301. Enter between 301L.

  When the final sheet of the sheet bundle is discharged onto the processing tray 330 (S104), this final sheet alignment process is started (S105). The final sheet discharged onto the processing tray 330 is first abutted against the trailing edge stopper 331 by the action of the pull-in paddle 360 or the like. Next, the aligning means 340 and 341 starts the aligning operation at the end in the sheet width direction. When the aligning operation of the sheet width direction end portion is started, in order to synchronize with this, the upper jaw portion 301U of the stapler 301 is formed in order to make the gap distance of the stapler 301 smaller than the first gap distance L. Starts to descend (S105). That is, the stapler 301 is in the first binding position until the trailing edge of the final sheet discharged onto the processing tray 330 is abutted against the trailing edge stopper 331 at the predetermined binding position (any one of positions A and D in FIG. 2). Is waiting in a state where the frontage distance L is maintained. Then, the upper jaw portion 301U of the stapler 301 starts to descend during the alignment operation of the end portion in the width direction of the final sheet.

  Then, the alignment of the end portions in the width direction of the final sheet by the alignment units 340 and 341 is completed (S106). Further, the lowering of the upper jaw portion 301U of the stapler 301 is also completed before the sheet alignment by the alignment means 340 and 341 is completed (S106). Accordingly, the stapler 301 before the binding operation at the predetermined binding position (any one of the positions A and D in FIG. 2) is held at the second frontage distance M that is narrower than the first frontage distance L (M <L). Then, the stapler 301 clinches the sheet bundle from the position of the frontage distance M that is narrowed before the binding operation, and staples the stitches (S107). The sheet bundle that has been stapled is discharged onto the stack tray by the bundle discharge roller pair (S108).

  In the present embodiment, the descending position control up to the frontage distance M of the stapler 301 counts the number of rotation pulses of the clinch motor that drives the cam mechanism from the home position detected using a sensor provided in the stapler 301. Is done. The frontage distance M is determined according to the output waveform of the clinch motor in the stapler 301. That is, since the bundle thickness of the sheet bundle is detected based on the power consumption (needle binding load), the frontage distance M can be set according to the bundle thickness. These controls are performed based on the calculation results in the CPU circuit unit 150.

The front opening distance M before the binding operation varies depending on the binding conditions such as the bundle thickness and the number of sheets, and is controlled by a value determined in advance according to the binding conditions. In general, when the bundle distance is M _L when the bundle thickness is thick or the number of bundles is large, and the gap distance is M _S when the bundle thickness is thin or the number of bundles is small, M _L > M _S The relationship is as follows.

  As described above, the gap distance M of the stapler 301 can be set to be smaller than the first gap distance L during the alignment operation of the final sheet by the alignment means 340 and 341 because the trailing edge of the sheet bundle including the final sheet can be set. This is because it has already entered between the upper jaw portions 301U and 301L. For this reason, even if the curl at the rear end of the sheet is large, the rear end of the sheet does not collide with the upper jaw and cause misalignment. For this reason, before starting the binding operation, the upper jaw portion 301 is lowered during the final sheet aligning operation by the aligning means 340 and 341 to a second front opening distance M that is narrower than the first front opening distance L. It becomes possible to do. Furthermore, the frontage distance M can be reduced to the minimum frontage distance according to the binding condition.

  As described above, by controlling the position of the frontage distance of the stapler 301, the sheet processing time required for staple binding can be shortened. Since the time required for needle binding can be shortened in this way, the productivity of the entire image forming apparatus can be improved.

  Specifically, according to the above-described embodiment, for example, the effect of creating 50 or 100 copies of a bundle of 100 sheets by one-point binding processing is verified. Note that the opening distance M of the sheet bundle of 100 sheets is set to 12 to 13 mm. In this case, the clinching time TD (frontage distance L = 13 mm) at one location was 150 ms (= 0.15 seconds). In contrast to this, if the conventional control that does not narrow the frontage distance of the stapler 301 is used, the clinch time TO (frontage distance = 30 mm) at one location is 400 ms (= 0.4 seconds). Therefore, according to the present embodiment, the processing time required for one-point binding of one sheet bundle is reduced by 250 ms (= 0.25 seconds) as compared with the conventional comparative example. Therefore, the processing time can be reduced by approximately 12.5 seconds for 50 copies, and 25 seconds for 100 copies.

  As described above, according to the present embodiment, the position of the stapler is narrowed during the final sheet aligning operation, and the size of the apparatus, the structure of the apparatus, and the cost are not increased. The time required for the binding process can be shortened and the productivity can be improved.

  Further, according to the present embodiment, the frontage distance before the binding operation is narrowed to the minimum frontage distance capable of the binding operation in accordance with the binding conditions such as the number of sheet bundles and the bundle thickness. This makes it possible to further improve the productivity when the number of sheet bundles is small or when the sheets are made of relatively thin sheets.

  In the above-described embodiment, one-point binding is illustrated as an example of the number of binding positions for one sheet bundle. However, the present invention is effective even when binding at two or more positions. When the binding process is performed at two or more locations on one sheet bundle, the upper jaw portion 301U rises after the clinching operation at the first location is completed, but the following distance M is maintained while maintaining the frontage distance M with the lower jaw portion 301L. It is even better to prepare for the clinching operation. This not only shortens the time required for the binding process at each binding location regardless of the number of locations for the binding process, but also increases the productivity by further reducing the time required for the binding process as the number of binding locations increases. Can be made.

  In the above-described embodiment, the type of stapler in which the upper jaw portion 301U is movable is illustrated, but the present invention is not limited to this. For example, a stapler in which only the lower jaw portion 301L is movable may be used, or a stapler in which both the upper and lower jaw portions 301U and 301L are movable may be obtained, and similar effects can be obtained.

  In the above-described embodiment, the configuration in which the present invention is applied to the flat stitching processing unit in the finisher 600 is exemplified, but the present invention is not limited to this. For example, the same effect can be obtained even when the present invention is applied to the saddle stitching processing unit in the finisher 600.

  In the above-described embodiment, the copying machine is exemplified as the image forming apparatus. However, the present invention is not limited to this, and may be another image forming apparatus such as a printer or a facsimile apparatus. Alternatively, the image forming apparatus may be another image forming apparatus that combines these functions. The same effect can be obtained by applying the present invention to a sheet processing apparatus used in these image forming apparatuses.

  In the above-described embodiment, the sheet processing apparatus that is detachable from the image forming apparatus main body 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.

Schematic sectional view showing the entire image forming apparatus provided with a sheet processing apparatus Schematic top view of flat stitching processing unit in sheet processing apparatus Schematic cross-sectional view of a side stitching processing unit in a sheet processing apparatus Schematic top view of the stapler unit moving mechanism in the flat stitching processing section Schematic cross section showing the frontage distance of the stapler The flowchart figure which shows the flow of operation | movement at the time of a binding process FIG. 2 is a block diagram illustrating a configuration of a control unit that controls the entire image forming apparatus.

Explanation of symbols

A, B, C, D ... Binding position L ... Frontage distance (first frontage distance)
M ... frontage distance (second frontage distance)
P ... Sheet 100 ... Image forming apparatus main body 150 ... CPU circuit unit (control means included in the image forming apparatus main body)
159 ... Finisher control section (control means possessed by the finisher)
200 ... saddle stitching processing unit 218 ... stapler 300 ... flat stitching processing unit 301 ... stapler (binding means)
301L ... lower jaw part (second binding part)
301U ... Maxilla (first binding part)
330 ... processing tray 331 ... rear end stoppers 340 and 341 ... alignment means 600 ... finisher (sheet processing apparatus)

Claims (7)

A binding unit that sequentially enters between the first binding unit and the second binding unit and sandwiches and stacks the stacked sheet bundle, and a sheet that enters between the first binding unit and the second binding unit. A sheet processing apparatus having alignment means for aligning and a control means for controlling the binding means,
The control means causes the frontage between the first binding portion and the second binding portion of the binding means to wait at a first frontage distance until the final sheet of the sheet bundle enters between the binding portions, and the alignment The sheet processing apparatus is controlled to change to a second frontage distance before starting the binding operation that is smaller than the first frontage distance before the final sheet aligning operation by the means is completed.   2. The sheet processing apparatus according to claim 1, wherein the control unit changes the second frontage distance in accordance with at least one binding condition of the number of sheets bundled, the bundle thickness, and the curl amount.   The sheet processing apparatus according to claim 2, wherein the control unit sets the second frontage distance to a minimum frontage distance at which a binding operation can be performed under the binding condition.   4. The image forming apparatus comprising: an image forming unit that forms an image on a sheet; and a sheet processing apparatus that performs processing on the sheet on which the image is formed. 5. An image forming apparatus comprising the sheet processing apparatus according to claim 1. An image forming apparatus comprising: an image forming unit that forms an image on a sheet; a sheet processing device that performs processing on the sheet on which the image is formed; and a control unit that controls the sheet processing device.
The sheet processing apparatus includes a binding unit that sandwiches and stacks sheet bundles that are sequentially entered and stacked between the first binding unit and the second binding unit, the first binding unit, and the second binding unit. Alignment means for aligning the sheet that has entered between the sections,
The control means causes the frontage between the first binding portion and the second binding portion of the binding means to wait at a first frontage distance until the final sheet of the sheet bundle enters between the binding portions, and the alignment An image forming apparatus that controls to change to a second frontage distance before starting the binding operation that is smaller than the first frontage distance before the final sheet alignment operation by the means is completed.   The image forming apparatus according to claim 5, wherein the control unit changes the second frontage distance in accordance with at least one binding condition of the number of sheets bundled, the bundle thickness, and the curl amount. The image forming apparatus according to claim 6, wherein the control unit sets the second frontage distance to a minimum frontage distance at which a binding operation can be performed under the binding condition.

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