JP4921192B2 - Sheet cutting apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a sheet post-processing apparatus and an image forming apparatus, and more particularly to a sheet cutting apparatus for performing a cutting process on a booklet in which a plurality of sheets are combined, and an image forming apparatus including the sheet cutting apparatus.

  2. Description of the Related Art Conventionally, a cutting device (trimmer) that combines a central portion of a plurality of sheets and cuts one end of a sheet bundle that is folded in two at a combining position to improve the appearance is widely used as proposed in Patent Document 1. Are known.

  For example, in the cutting apparatus as shown in FIG. 9, the sheet bundle as shown in FIG. 10 (a) discharged from the booklet-shaped sheet bundle creation apparatus is received by the conveyor belt, and the sheet bundle is sent to the downstream cutting section. Then, the sheet bundle is positioned and cut in the conveyance path. Then, as shown in FIG. 10 (b), the cutting waste cut by the cutting blade when the sheet bundle is cut is stored in the waste box 635. Therefore, a shutter 625 that is opened to form a cutting waste passage when the sheet bundle is cut and serves as a conveyance guide when the sheet bundle is conveyed is provided in the conveyance path.

  As shown in FIG. 9, when not cut, the shutter 625 is urged by a torsion coil spring (not shown) to serve as a conveyance guide that forms a sheet bundle conveyance path. At the time of cutting the sheet bundle, the movable blade (upper blade) 633 is driven by a motor and a link (not shown), and the movable blade 633 descends toward the fixed blade (lower blade) 634 to cut the sheet bundle. At this time, as the movable blade 633 descends, the shutter 625 starts to be pushed and opened by the cam 636 provided on the movable blade 633, and the opening amount becomes maximum immediately before the sheet bundle cutting.

  The movable blade 633 traverses the sheet bundle conveyance path while cutting the sheet bundle, and when the movable blade 633 reaches the bottom dead center in the vicinity of the lowermost point of the movable region of the link, the opening amount of the shutter is maximized. When the movable blade 633 rises to the same position as the position where the shutter opening amount is maximized, the shutter 625 starts to close, and at the top dead center of the movable blade 633 near the uppermost point of the movable area of the link, the sheet bundle conveying path is passed. Form. The cutting waste falls into the waste box 635 while the cutting waste passage is opened by the shutter 625.

JP 2000-198613 A

  However, when the number of sheets in the bundle is large, a large amount of cutting waste is generated, and it may take time until the cutting waste falls into the cutting waste box 635. In such a case, when the shutter 625 is closed in a state where the cutting waste does not fall down, the cutting waste includes the shutter 625 when the movable blade 633 moves up and passes through the sheet bundle conveyance passage. Fall on top. In this state, the next sheet bundle is conveyed on the shutter 625, whereby the cutting waste is pushed out. Then, the extruded cutting waste may block the sensors in the sheet bundle conveyance path, which may cause erroneous detection.

  Also, if the shutter 625 is opened for a long time, the next sheet bundle after the cut sheet bundle cannot enter the cutting section, and the productivity is lowered.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a sheet cutting apparatus that appropriately processes cutting waste without affecting productivity, and an image forming apparatus including the sheet cutting apparatus. is there.

A typical means in the present invention for solving the above-described problems is a sheet bundle conveyance path for conveying a sheet bundle, and a sheet bundle in the sheet bundle conveyance path by cutting from the first position to the second position. A sheet bundle cutting means having a movable blade , a fixed blade that cuts the sheet bundle in cooperation with the movable blade, and a shutter that interlocks with the movement of the movable blade from the first position to the second position. An opening / closing member; a cutting waste storage means for storing the cutting waste cut by the sheet bundle cutting means through the waste passage; and a shutter means for opening and closing the waste passage; and the shutter means includes the movable blade. When in the first position, the waste passage is closed to form a part of the sheet bundle conveyance passage, and when the movable blade moves from the first position to the second position, the shutter closing member said A passage opening not, when the movable blade and the shutter opening and closing member is in the second position, the opening amount of the waste passage of the shutter unit by the shutter opening and closing member is a maximum, the movable blade and the shutter When the opening / closing member stops at the second position, the maximum open state of the waste passage is maintained for a predetermined time.

  According to the present invention, after the movable blade of the sheet bundle cutting means moves and cuts the sheet bundle, the cutting waste passage is kept open for the time set by the shutter means, so that the cutting waste from the movable blade is surely removed. It can be stored in the cutting waste storage means.

  Next, a sheet cutting apparatus and an image forming apparatus using the sheet cutting apparatus according to an embodiment of the present invention will be specifically described with reference to the drawings.

[First Embodiment]
FIG. 1 is a cross-sectional explanatory view of a copying machine that is an image forming apparatus using the sheet cutting apparatus according to the first embodiment, and FIG. 2 is a cross-sectional explanatory view of the sheet cutting apparatus.

(Overall configuration of image forming apparatus)
As shown in FIG. 1, the copier 1000 of the present embodiment includes a document feeding unit 100, an image reader unit 200 and a printer unit 300, a folding processing unit 400, a finisher 500, a saddle stitch bookbinding unit 800 (see FIG. 2), Has inserter 900 and the like. The folding processing unit 400, the saddle stitch bookbinding unit 800, the inserter 900, and the like can be provided as options.

  Referring to FIG. 1, a document is set on tray 1001 of document feeder 100 in an upright state as viewed from the user and in a face-up state (the surface on which an image is formed is upward). It is assumed that the binding position of the document is located at the left end portion of the document. Documents set on the tray 1001 are conveyed by the document feeder 100 one by one from the first page in the left direction (arrow direction in the figure), that is, with the binding position as the leading edge. Further, the original is further conveyed from the left to the right on the platen glass 102 via a curved path, and then discharged onto the discharge tray 112. At this time, the scanner unit 104 is held in a predetermined position, and the document reading process is performed when the document passes from the left to the right on the scanner unit 104 (document flow scanning). .

  When the document passes over the platen glass 102, the document is irradiated by the lamp 103 of the scanner unit 104, and the reflected light from the document is guided to the image sensor 109 via the mirrors 105, 106, 107 and the lens 108. .

  It is also possible to perform document reading processing by temporarily stopping the document conveyed by the document feeder 100 on the platen glass 102 and moving the scanner unit 104 from left to right in this state (document fixed reading). ). When reading a document without using the document feeding unit 100, the user lifts the document feeding unit 100 and sets the document on the platen glass 102. In this case, the above-described original fixed reading is performed.

  The document image data read by the image sensor 109 is subjected to predetermined image processing and sent to the exposure control unit 110. The exposure control unit 110 outputs laser light corresponding to the image signal. With this laser beam output, an image is formed by image forming means using an electrostatic recording system.

  That is, the laser beam is irradiated onto the photosensitive drum 111 while being scanned by the polygon mirror 110a, and an electrostatic latent image corresponding to the scanned laser beam is formed on the photosensitive drum 111.

  The electrostatic latent image formed on the photosensitive drum 111 is developed by the developing unit 113 and visualized as a toner image. On the other hand, the recording sheet is conveyed to the transfer unit 116 from any of the cassettes 114 and 115, the manual feeding unit 125, and the double-sided conveyance path 124. Then, the visualized toner image is transferred to the recording sheet P in the transfer unit 116. The recording sheet after the transfer is subjected to a fixing process by a fixing unit 177.

  The recording sheet that has passed through the fixing unit 177 is once guided to the path 122 by the flapper 121, and after the trailing end of the recording sheet has passed through the flapper 121, the recording sheet is switched back and conveyed to the discharge roller 118 by the flapper 121. The recording sheet is discharged from the printer unit 300 by the discharge roller 118. Accordingly, the surface on which the toner image is formed can be discharged from the printer unit 300 in a downward state (face-down) (reverse discharge).

  As described above, the recording sheet is discharged out of the apparatus face down. As a result, when the image forming process is performed in order from the first page, for example, when the image forming process is performed using the document feeder 100, or when the image forming process is performed on the image data from the computer, the page order is aligned. be able to.

  When image forming processing is performed on both sides of the sheet, the sheet is guided straight from the fixing unit 177 toward the discharge roller 118, and the sheet is switched back immediately after the trailing edge of the sheet passes through the flapper 121. Guide to the duplex transport path.

(Folding section and finisher)
Next, configurations of the folding processing unit 400 and the finisher 500 will be described with reference to FIGS. 1 and 2.

  The folding processing unit 400 has a conveyance path 131 for introducing the sheet discharged from the printer unit 300 and guiding it to the finisher 500 side. On the conveyance path 131, conveyance roller pairs 130 and 133 are provided. A switching flapper 135 provided in the vicinity of the conveying roller pair 133 is for guiding the sheet conveyed by the conveying roller pair 130 to the folding path 136 or the finisher 500 side.

  When the sheet folding process is performed, the switching flapper 135 is switched to the folding path 136 and the sheet is guided to the folding path 136. The sheet guided to the folding path 136 is conveyed to the folding roller and folded into a Z shape. On the other hand, when the folding process is not performed, the switching flapper 135 is switched to the finisher 500 side, and the sheet discharged from the printer unit 300 is directly fed through the conveyance path 131.

  The sheet conveyed through the folding path 136 is folded by the folding rollers 140 and 141 by a loop formed by abutting the leading end against the stopper 137. The sheet is Z-folded by further folding the loop formed by abutting the bent portion against the upper stopper 143 by the folding rollers 141 and 142. The Z-folded sheet is sent to the conveyance path 131 via the conveyance path 145, and is discharged to the finisher 500 attached to the downstream side in the sheet conveyance direction (hereinafter simply referred to as “downstream side”) by the conveyance roller pair 133. Note that the folding processing operation by the folding processing unit 400 is selectively performed.

  The finisher 500 performs processing to take in sheets from the printer unit 300 conveyed via the folding processing unit 400, align the plurality of taken-in sheets, and bundle them as one sheet bundle. The finisher 500 is for performing sheet processing such as stapling processing (binding processing) for stapling the trailing end side of the sheet bundle, sorting processing, non-sorting processing, and the like.

  As shown in FIG. 2, the finisher 500 has a conveyance path 520 for taking the sheet conveyed through the folding processing unit 400 into the apparatus, and the conveyance path 520 is provided with a plurality of conveyance roller pairs. Yes.

  A punch unit 530 is provided in the middle of the conveyance path 520, and the punch unit 530 operates as necessary to perform a punching process at the rear end of the conveyed sheet.

  A flapper 513 provided at the end of the transport path 520 switches the route between an upper discharge path 521 and a lower discharge path 522 connected to the downstream side. The upper discharge path 521 performs discharge to the upper stack tray. 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 are subjected to sorting processing and stapling processing according to settings from the operation unit. Thereafter, the stack tray 700, It is discharged to 701.

  Note that the above-described stapling process is performed by the stapler 560, and the stapler 560 can be moved in the sheet width direction and can be stapled at an arbitrary position on the sheet.

(Saddle stitch bookbinding)
Next, the configuration of the saddle stitch bookbinding unit 800 will be described with reference to FIG. The sheet switched to the right side by the switching flapper 514 provided in the middle of the lower discharge path 522 passes through the saddle discharge path 523 shown in FIG. The sheet is delivered to a pair of saddle entrance rollers 801, a carry-in entrance is selected by a flapper 802 operated by a solenoid according to the size, and is carried into a storage guide 803 of the saddle stitch bookbinding portion 800. The loaded sheet is conveyed by the sliding roller 804 until the leading end contacts the movable sheet positioning member 805. The saddle entrance roller pair 801 and the sliding roller 804 are driven by a motor M1. In addition, a stapler 820 is provided in the middle of the storage guide 803 so as to face the storage guide 803. The stapler 820 is divided into a driver 820a that projects a staple needle S (see FIG. 3) and an anvil 820b that bends the projected needle. The sheet positioning member 805 stops at a position where the center portion in the sheet conveyance direction becomes the binding position of the stapler 820 when the sheet is carried in. The sheet positioning member 805 is movable under the driving of the motor M2, and changes its position according to the sheet size.

  A folding roller pair 810 (810a, 810b) is provided on the downstream side of the stapler 820, and a protruding member 830 is provided at a position opposite to the folding roller pair 810. The projecting member 830 has a position retracted from the storage guide 803 as a home position, and folds while pushing the sheet bundle into the nip of the pair of folding rollers 810 by projecting toward the sheet bundle stored by driving the motor M3. It is. Thereafter, the protruding member 830 returns to the home position again. In addition, a pressure F1 sufficient to crease the bundle is applied between the pair of folding rollers 810 by a spring (not shown). The creased sheet bundle is discharged to a folded bundle discharge tray (not shown) via the first folding conveyance roller pair 811 (811a, 811b) and the second folding conveyance roller pair 812 (812a, 812b). The first fold conveyance roller pair 811 and the second fold conveyance roller pair 812 are also subjected to pressures F2 and F3 sufficient to convey and stop the folded bundle.

  The folding roller pair 810, the first folding transport roller pair 811 and the second folding transport roller pair 812 are rotated at the same speed by the same motor M4 (not shown).

  Further, when folding the sheet bundle bound by the stapler 820, the sheet positioning member 805 is moved away from the position at the time of the stapling process so that the staple position of the sheet bundle comes to the nip position of the pair of folding rollers 810 after the stapling process is completed. Descent a predetermined distance. Accordingly, the sheet bundle can be folded around the position where the stapling process is performed.

  In FIG. 2, reference numeral 815 denotes an alignment plate pair that has a surface protruding to the storage guide 803 while rotating around the outer peripheral surfaces of the pair of folding rollers 810a and 810b and aligns the sheets stored in the storage guide 803. The alignment plate pair 815 is positioned in the width direction of the sheet by moving in the sandwiching direction with respect to the sheet under the driving of the motor M5.

  A press unit 860 is provided on the downstream side of the second fold conveyance roller pair 812 so as to spatially overlap the fold bundle discharge tray. The press unit 860 moves in a direction perpendicular to the sheet bundle conveying direction, nips the fold portion of the sheet bundle by the press roller pair 861, and moves to strengthen the fold. In this way, the booklet-shaped sheet bundle T shown in FIG. 3 is formed.

(Trimmer unit)
Next, the trimmer unit 600 will be described with reference to FIG. The trimmer unit 600 of this embodiment includes a first transport unit 610, a second transport unit 620, and a trim unit 630 that constitute a sheet bundle transport unit in order from the upstream side in the sheet transport direction (hereinafter simply referred to as “upstream side”). A third transport unit 640, a fourth transport unit 650, and a discharge unit 660 are disposed.

  The first conveying unit 610 has a lower conveying belt 611 only on the lower side in order to receive a sheet bundle from the saddle stitch binding unit 800, and side guides 612 are disposed on both sides of the lower conveying belt 611, and these are the sheets. By operating in the width direction of the bundle, the skew of the sheet can be corrected. The side guide 612 is provided with a pressing guide 614 that prevents the sheet bundle from being opened, so that the sheet bundle can be smoothly transferred to the second conveying unit 620.

  A first conveyance unit inlet sensor 615 and a first conveyance unit outlet sensor 616 that detect the presence or absence of a sheet bundle are disposed on the upstream side and the downstream side of the holding guide 614. Conveying claws 613 are disposed on both sides of the lower conveying belt 611. The conveyance claw 613 can move in the sheet bundle conveyance direction, and moves at the same speed as the lower conveyance belt 611 to deliver the sheet bundle to the second conveyance unit 620. When a slip occurs between the lower conveyance belt 611 and the sheet bundle, the conveyance claw 613 comes into contact with the rear end of the sheet bundle on the side opposite to the fold and conveys the sheet bundle while pushing the rear end of the sheet bundle so as not to be conveyed.

  Next, the second, third, and fourth transport units have a pair of transport belts 621, 622, 645, 646, and 655, 656, respectively, and the upper and lower transport belts of each transport unit are driven by the same motor. These are configured to have the same conveyance speed.

  FIG. 4 is an enlarged explanatory view of the trim part. As shown in FIG. 4, a second conveyance unit entrance sensor 623 is disposed in the clamping portion J of the second conveyance unit 620 so as to detect that a sheet bundle has been delivered to the second conveyance unit 620. It has become. The third transport unit 640 is provided with a stopper 641 that can appear and disappear in the transport path and can also move in the sheet transport direction. The stopper 641 serves as a sheet bundle positioning means for positioning the sheet bundle to be conveyed in the sheet bundle conveyance path. The stopper 641 is driven by a motor via cams 642 and 648 with the K portion as a rotation center, and is placed on the conveyance path. Appearance and evacuation are possible. The stopper 641 is mounted on the slide block 643 and is driven by a motor (not shown) along the slide guide 644, and moves according to the sheet bundle conveyance direction size and the sheet bundle stop position. The fourth conveyance unit 650 conveys the sheet bundle upward.

  In the trim part 630, a cutter unit 631 serving as a sheet bundle cutting means is arranged in a direction perpendicular to the conveyance path. FIG. 7 is an explanatory perspective view of the cutter unit 631. FIG. 7 shows components only in the vicinity of the third conveyance unit 640, and the upper conveyance belt and the like are omitted.

  The cutter unit 631 is driven by a motor (not shown), and moves up and down in a direction perpendicular to the conveyance surface by a link 637. The holding member 632 and the upper blade 633 are disposed in the cutter unit 631. The upper blade 633, which is a movable blade, can be moved between the first position where the cutting operation starts and the second position where the cutting operation is completed by the vertical movement of the cutter unit 631. In this embodiment, the top dead center U (see FIG. 6) near the uppermost point of the ascending movable area of the cutter unit 631 is set to the first position, and the lower dead center near the lowermost point of the descending movable area of the cutter unit 631 Point D (see FIG. 8) is set to the second position. The motor rotation stop control is performed so that the cutter unit 631 stops at the top dead center U and the bottom dead center D. The movable region of the cutter unit 631 is set so as to secure a stroke necessary for cutting the sheet bundle in consideration of manufacturing errors of components, mounting errors, motor response deviation, and the like. Therefore, the top dead center U and the bottom dead center D of the upper blade 633 are not necessarily coincident with the uppermost point and the lowermost point of the movable region.

  The upper blade 633 is normally stopped at the top dead center as an initial position. Then, when cutting the sheet bundle, the sheet moves downward from the top dead center toward the bottom dead center, and the upper blade 633 and the fixed lower blade 634 cooperate with each other in the meantime. Cut. When the cutter unit 631 is lowered, the pressing member 632 contacts the sheet bundle in advance. The pressing member 632 is urged downward by a spring (not shown). For this reason, it is possible to cut the sheet bundle while sandwiching the sheet bundle.

When the cutter unit 631 is lowered, the shutter 625 disposed on the downstream side of the second conveyance unit 620 is pushed by cams 636 serving as shutter opening / closing members attached to both sides of the cutter unit 631 outside the sheet bundle conveyance path. It is. As a result, the shutter 625 opens and closes (rotates) around the fulcrum Q as the cutter unit 631 descends. The shutter 625 constitutes shutter means for opening and closing a cutting waste passage for allowing cutting waste to pass to the cutting waste storage means.

  Further, a waste box 635 serving as a cutting waste storage means for storing cutting waste is disposed below the cutter unit 631, and the waste cut by the cutter unit 631 is stored. For example, when the upper blade 633 is at the top dead center and the shutter 625 is not pushed by the cam 636, the shutter 625 is urged by a torsion coil spring (not shown) to convey the lower blade 634 from the conveyor belt 622. Thus, a part of the sheet bundle conveyance path is formed. At this time, the shutter 625 closes the cutting waste path to the waste box 635.

  As shown in FIG. 2, a discharge unit 660 is disposed on the most downstream side, and stacks of sheet bundles conveyed by the fourth conveyance unit 650 are stacked.

(Control part)
FIG. 5 is a block diagram of the copying machine 1000. The CPU circuit unit 150 includes a CPU (not shown), and controls a document feeding control unit 101, an image reader control unit 201, an image signal control unit 202, a printer in accordance with a control program stored in the ROM 151 and settings of the operation unit 1. The controller 301, the folding processing controller 401, the finisher controller 501 and the external I / F 203 are controlled. The document feeding control unit 101 controls the document feeding unit 100, the image reader control unit 201 controls the image reader unit 200, and the printer control unit 301 controls the printer unit 300. Further, the folding processing control unit 401 controls the folding processing unit 400, and the finisher control unit 501 controls the finisher 500, the trimmer unit 600, the saddle stitch binding unit 800, and the inserter 900.

  The operation unit 1 includes a plurality of keys for setting various functions relating to image formation, a display unit for displaying a setting state, and the like. Then, a key signal corresponding to the operation of each key by the user is output to the CPU circuit unit 150, and corresponding information is displayed on the display unit based on the signal from the CPU circuit unit 150.

  The RAM 152 is used as an area for temporarily storing control data and a work area for operations associated with control. An external I / F 203 is an interface between the copying machine 1000 and an external computer 204, develops print data from the computer 204 into a bitmap image, and outputs it as image data to the image signal control unit 202. Further, an image of a document read by an image sensor (not shown) is output from the image reader control unit 201 to the image signal control unit 202. The printer control unit 301 outputs the image data from the image signal control unit 202 to an exposure control unit (not shown).

(Sheet cutting operation)
Next, based on the above configuration, the operation of each part of the sheet bundle conveying unit in the trimmer unit 600 of the present invention will be described together with the flow of the sheet bundle.

  The sheet bundle that has been creased by the press unit 860 is resumed and delivered to the first conveyance unit 610 of the trimmer unit 600. The lower conveying belt 611 of the first conveying unit 610 rotates and conveys the sheet bundle. After the sheet bundle is detected by the first conveying unit outlet sensor 616, conveyance is temporarily stopped. Thereafter, the side guides 612 disposed on both sides of the transport path perform an alignment operation. Thereafter, the conveyance of the sheet bundle is resumed by the conveyance claws 613 and the lower conveyance belt 611 arranged on the upstream side of the first conveyance unit. Then, when the sheet bundle is detected by the second conveyance unit entrance sensor 623 disposed in the clamping unit J of the second conveyance unit 620, the conveyance claw 613 is retracted upstream of conveyance. On the other hand, the sheet bundle passes through the second conveying unit 620 and the trim unit 630 and is conveyed to the third conveying unit 640.

  In the third transport unit 640, a stopper 641 appears in advance on the transport path at an appropriate position according to the size of the transported sheet bundle, and the sheet bundle comes into contact with the stopper 641 and stops at a predetermined position ( FIG. 6). Thereafter, the conveyance belt of the third conveyance unit 640 stops, and as shown in FIG. 8, the cutter unit 631 of the trim unit 630 starts to descend, and the upper blade 633 cuts the rear end of the sheet bundle. At this time, the shutter 625 is pushed by the cam 636 that descends in conjunction with the lowering of the cutter unit 631, thereby opening the cutting waste path from the cutting portion to the waste box 635 to the maximum before the sheet bundle is cut. ing. The opening amount of the cutting waste passage by the shutter 625 becomes maximum when the cutter unit 631 is at the bottom dead center. In the cam 636 in the present embodiment, after the shutter 625 is pushed by the cam 636 and the opening amount of the cutting waste passage is maximized, the linear portion of the cam 636 is the upper surface of the shutter 625 up to the lowest movable region of the link 637. The shutter 625 is maintained at the maximum open position. (FIG. 8) The bottom dead center of the cutter unit 631 is set in the movable region of the link 637 where the opening amount of the cutting waste passage is maximized.

  Then, after reaching the bottom dead center that is near the lowest movable point of the link 637, the cutter unit 631 stops for a set time and then returns to the initial position (top dead center). In this operation, the stop time (set time) at the bottom dead center of the cutter unit 631 is set to a predetermined time sufficient for reliably dropping the cutting waste from the upper blade 633. In this embodiment, after the sheet bundle is cut by the cutter unit 631, the sheet bundle that is next conveyed to the cutter unit 631 and the sheet bundle when the number of sheets in the bundle is the minimum is the cutter unit 631. It is set shorter than the time until it is transported. That is, the time is set in time for the minimum bundle number of sheet bundles created by the saddle stitch bookbinding unit 800.

  Further, as the cutter unit 631 returns to the initial position, the cam 636 is separated from the shutter 625, and the notch passage of the shutter 625 is closed by a torsion coil spring (not shown). Thereafter, the stopper 641 is retracted, and the conveyance of the third conveyance unit 640 is resumed. The sheet bundle is transferred to the fourth conveyance unit 650 disposed downstream of the third conveyance unit 640.

  The sheet bundle conveyed upward by the fourth conveying unit 650 is discharged to the discharge unit 660 and sequentially stacked in a straw shape. By disposing the discharge port at the upper portion by the fourth conveying unit 650, the user's ability to take out the sheet bundle is improved.

  When the sheet bundle is continuously conveyed to the cutter unit 631 and cut as described above, the sheet bundle rear end is cut by the upper blade 633, and then a predetermined time period until the next sheet bundle is conveyed, The cutter unit 631 is stopped near the bottom dead center D. As a result, the shutter 625 maintains the maximum open state until the cutting waste falls into the waste bin 635, so that the cutting waste is reliably accommodated in the waste waste box 635.

  Then, the time for the upper blade 633 to stop at the bottom dead center is set within the bundle between the sheet bundle to be cut and the sheet bundle to be cut next when the number of sheets in the bundle is the minimum. The productivity of sheet bundle processing is not reduced.

[Second Embodiment]
Next, as a second embodiment, a case will be described in which the stop time at the bottom dead center D of the cutter unit 631 is changed according to the number of sheet bundles to be cut.

  In the first embodiment described above, the sheet bundle is conveyed in the minimum number of sheets of the sheet bundle created by the saddle stitch bookbinding section 800 for a predetermined stop time (set time) at the bottom dead center D of the cutter unit 631. It was set to be in time within the interval. However, when a plurality of sheet bundles are created and the cutting process is performed on each bundle, the time required for the cutting process greatly depends on the number of sheets in the bundle.

  Here, it is assumed that a time from when the sheet bundle is saddle-stitched through feeding to image formation, folded and strengthened by the press unit 860, and discharged. In addition, the time from receipt of the sheet bundle by the first conveyance unit 610 of the trimmer unit 600 to delivery to the second conveyance unit 620 is T2. Also, T3 is the time from when the second conveying unit 620 receives the sheet bundle, the trim unit 630 cuts, and passes through the third conveying unit 640 to the fourth conveying unit 650. Further, T4 is the time from the receipt by the fourth transport unit 650 to the ejection to the ejection unit 660. At this time, if T1 ≧ T2 + T3 + T4, the sheet bundle is in time, and productivity is not affected.

  Here, n is the number of sheets in the sheet bundle, Tm is the time taken for one sheet to be sent from the feeding guide to the storage guide 803 of the saddle stitching bookbinding section 800 through image formation. Let Ti be the time required for the sheet bundle processing until the sheet is discharged. At this time, it can be expressed as T1 = n × Tm + Ti.

  Further, assuming that the stop time at the bottom dead center D of the upper blade 633 in the trim part 630 is T3a, and the other time is T3b, T3 = T3a + T3b.

  Therefore, T1 = n × Tm + Ti ≧ T2 + (T3a + T3b) + T4. From this, it is understood that the stop time T3a at the bottom dead center D can be extended by n × Tm every time n sheets increase.

  Information on the number of sheets in the sheet bundle is transmitted from the CPU circuit unit 150 of FIG. 5 to the finisher control unit 501, and the finisher control unit 501 controls the stop time (set time) at the bottom dead center D of the cutter unit 631 according to the information. To do.

  As described above, the stop time at the bottom dead center of the cutter unit 631 is set and controlled in accordance with the number of sheets to be processed. The shutter 625 is opened. As a result, a necessary opening time can be ensured even when the number of sheet bundles is large and a large amount of cutting waste occurs. For this reason, the cutting waste from the upper blade 633 is surely dropped into the waste box 635, and the cutting waste attached to the upper blade 633 does not remain in the sheet bundle conveyance passage when the upper blade 633 returns to the upper side of the sheet bundle conveyance passage. .

  The stop time is set to be shorter than the time from when the sheet bundle is cut by the cutter unit 631 until the next sheet bundle conveyed to the cutter unit 631 is conveyed to the cutter unit 631. Then, the opening time of the cutting waste passage is changed according to the number of conveyed sheet bundles and is set so as to be within the inter-bundle time, so that the productivity is not affected. In other words, when the number of sheet bundles is small, the time for creating some sheet bundles is short, but the amount of trimming waste generated when trimming is also small. There is no problem even if it does not decrease.

FIG. 4 is a cross-sectional explanatory diagram of an image forming apparatus including a sheet cutting device. It is a cross-sectional explanatory drawing of a folding process part, a finisher, a saddle stitch bookbinding part, and a trimmer unit. It is explanatory drawing of the sheet bundle which carried out the folding process. It is a section explanatory view of a sheet cutting device. It is a block diagram of a control part. It is explanatory drawing of the sheet | seat cutting apparatus in the state which has an upper blade in a top dead center. It is a perspective explanatory view of a sheet cutting device. It is explanatory drawing of the sheet | seat cutting apparatus in the state which has an upper blade in a bottom dead center. It is explanatory drawing of the sheet cutting apparatus which concerns on a prior art. It is explanatory drawing of the sheet bundle which carried out the folding process.

Explanation of symbols

P ... Recording sheet 1 ... Operation unit
100 ... Document feeder
1000 ... Copier
101 ... Document feed control unit
111… Photosensitive drum
112… discharge tray
113… Developer
116… Transcription part
145… Conveyance path
177… Fixing part
300 ... Printer section
400 ... Folding section
500… Finisher
520… Conveyance path
551… Bundle discharge roller pair
560… stapler
610 ... 1st conveyance part
611 ... Lower conveyor belt
612… Side guide
613… Conveying claw
614… Holding guide
620 ... 2nd conveyance part
621,622… Conveyor belt
625 ... shutter
630… trim part
631… Cutter unit
632… Holding member
633… Upper blade
634… Lower blade
635… Scrap box
636… Cam
637… Link
640 ... 3rd conveyance part
641… Stopper
642,648 ... cam
643… Slide block
650 ... 4th transport section
660… discharge section
800 ... saddle stitch bookbinding
802 Flapper
803… Storage guide
805 ... Sheet positioning member
810… Folding roller pair
811, 812 ... Folding conveyance roller pair

Claims (7)

A sheet bundle conveyance path for conveying the sheet bundle;
A sheet bundle cutting comprising: a movable blade that moves from the first position to the second position to cut the sheet bundle in the sheet bundle conveyance path; and a fixed blade that cuts the sheet bundle in cooperation with the movable blade. Means,
Cutting waste storage means for storing the cutting waste cut by the sheet bundle cutting means through the waste passage,
Shutter means for opening and closing the waste passage;
A shutter opening and closing member that opens and closes the shutter means in conjunction with the movement of the movable blade from the first position to the second position;
Have
When the movable blade is in the first position, the shutter means closes the waste passage to form a part of the sheet bundle conveyance passage, and the movable blade moves from the first position to the second position. When moving, the waste passage is opened by the shutter opening and closing member ,
When the movable blade is in the second position, the opening amount of the waste passage of the shutter means by the shutter opening / closing member is maximum,
The sheet cutting device according to claim 1, wherein the movable blade is stopped at the second position so that the shutter opening / closing member maintains the waste passage of the shutter means in a fully opened state for a predetermined time . The sheet cutting apparatus according to claim 1, wherein the shutter opening / closing member is a cam member. The sheet cutting apparatus according to claim 1 or 2, wherein the first position is a top dead center, and the second position is a bottom dead center.   The predetermined time is the sheet bundle to be cut next after the sheet bundle is cut by the sheet bundle cutting means, and the sheet bundle when the number of sheets in the bundle is the minimum is conveyed to the sheet bundle cutting means. The sheet cutting device according to any one of claims 1 to 3, wherein the sheet cutting device is shorter than a time until it is done.   The sheet cutting apparatus according to claim 1, wherein the predetermined time is changed according to the number of sheets of the sheet bundle conveyed to the sheet bundle cutting means.   5. The predetermined time is shorter than a time until a sheet bundle to be cut next is conveyed to the sheet bundle cutting unit after the sheet bundle is cut by the sheet bundle cutting unit. The sheet cutting device according to 1.   6. An image forming apparatus comprising: an image forming unit that forms an image on a sheet; and a sheet cutting device that transports and cuts the image-formed sheets in a bundle, and the sheet cutting device includes: An image forming apparatus comprising the sheet cutting device according to claim 1.

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