JP4378264B2 - Sheet stacking apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a sheet stacking apparatus provided in association with a folding mechanism and apparatus for folding sheets, a sheet processing apparatus such as a finisher apparatus for performing saddle stitching and the like, and the sheet stacking apparatus or the sheet The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a digital multi-function machine provided with a processing apparatus as a single body or a separate body.

  Sheets folded by the sheet processing apparatus are discharged to a dedicated stacking tray, and the forms thereof are various. For example, as a basic form of a stacking tray configuration for stacking saddle-stitched sheet bundles, as shown in FIG. 33, a sheet discharge roller 83 for discharging a folded sheet 550 to the outside of the apparatus and a sheet 550 are stacked. A stacking tray 203 that has a rotation fulcrum above the sheet discharge port and a pressure arm 501 that presses the bulge of the folded sheet 550 on the stacking tray 203 is generally known. . In such a sheet stacking tray configuration, there are various problems.

  Of course, the folded sheet tends to swell, and when the next sheet is discharged there, it collides with the stacked sheet and does not stack cleanly. Therefore, in the invention described in Patent Document 1, the invention shown in FIG. The pressure arm 501 is added to the horizontal stacking tray 203 (corresponding to the lower tray in the embodiment described later), and is lifted from the stacking tray 203 so as not to cause sheet discharge resistance. When the number of stacked parts is large, the front end part does not come into contact, and therefore, a method of suppressing the swelling of the sheet 550 with the convex part 552 at the center part is adopted.

  On the other hand, in the invention described in Patent Document 2, as shown in FIG. 35, a large-size fixed stopper 561 and a small-size stopper 562 that can be moved forward and backward are provided at the downstream end of the stacking tray 203, and a small-size sheet bundle is placed at a fixed position. So that it can be loaded stably.

As a related invention, for example, the invention described in Patent Document 3 is also known.
Japanese Patent No. 3413056 JP 2002-137860 A JP 2002-104712 A

  However, in the invention described in Patent Document 1, it is sufficient that the stacked sheets are stacked at a fixed position, but from a large size (for example, A4 size in which the A3 size is folded in half) to a small size (for example, A5 in which the A4 size is folded in half). In general, the sheet stacking surface of the stacking tray 203 is slightly larger than the maximum size, and the stopper 551 is provided at the downstream end to prevent the stacked sheets from spilling down as described above. In this stacking tray 203, a small-size sheet bundle is not stably stacked at a fixed position, so that the effect of the pressure arm 501 is not exhibited as shown in FIG. 34, and stacking may be disturbed. .

  In the invention described in Patent Document 2, as shown in FIG. 36, the user has to operate the stopper 562 of the stacking tray 203 depending on the sheet size. There is.

  The present invention has been made in view of such a situation of the prior art, and an object of the present invention is to make it possible to satisfactorily stack sheets of a large size to a small size without depending on a user operation.

In order to achieve the above object, the first means has a discharge means for discharging the folded sheets, a stacking tray for stacking the sheets, and a rotation fulcrum on the upper side in the vicinity of the discharge means, In a sheet stacking apparatus that is provided so as to be able to rotate according to the height of the sheets stacked on the stacking tray and presses the upper surface of the sheet on the stacking tray, the arm according to the amount of rotation of the arm and means for changing the pressure of the means for changing the pre-Symbol pressure increases the higher the pressure the amount of rotation of the arm is increased, the higher the load of said arm lower sheet stacking height on the tray It is characterized by lowering.

The second means is that, in the first means, the distance from the contact point of the arm tip to the stacking tray to the discharge means is set shorter than the large sheet length and longer than the small sheet length. It is characterized by.

According to a third means, in the first means, the shape on the paper passing side of the arm is such that the inclination angle with respect to the stacking surface of the stacking tray on the side close to the stacking tray is inclined on the side away from the stacking tray It is characterized by being set larger than the corner .

According to a fourth means, in any one of the first to third means, the rotation fulcrum of the arm is shared or has a rotation fulcrum in the vicinity of the rotation fulcrum, and the sheet discharged at the leading end A sheet rear end pressing member provided integrally with the arm for pressing the rear end portion that has floated is further provided.

A fifth means is characterized in that, in any one of the first to fourth means, the stacking tray is set to have a gentle inclination angle in the vicinity of the arm tip .

A sixth means is characterized in that the image forming apparatus includes a sheet stacking apparatus according to any one of the first to fifth means.

  In the embodiment described later, the discharge means is the lower discharge roller 83, the stacking tray is the lower tray 203, the arm is the pressure arm 501, the rotation fulcrum is 501a, and the means for changing the pressing force is the tension spring. The rotatable roller corresponds to the guide roller 504, and the sheet trailing edge pressing member corresponds to the pressing arm 502.

According to the present invention, the pressing force of the arm is low for a small number of low-waist sheets, and the pressurizing force is high for a large number of thick and thin sheets, thereby improving the stackability of discharged sheets. .

  Embodiments of the present invention will be described below with reference to the drawings.

1. Overall Configuration FIG. 1 is a diagram showing a system configuration of an image forming system including a sheet post-processing apparatus and an image forming apparatus as a sheet processing apparatus according to a first embodiment of the present invention. And a part of the image forming apparatus.

  In FIG. 1, a sheet post-processing apparatus PD is attached to a side portion of the image forming apparatus PR, and a recording medium discharged from the image forming apparatus PR, here, a sheet is guided to the sheet post-processing apparatus PD. The sheet passes through a conveyance path A having post-processing means (in this embodiment, a punch unit 100 as a punching means) for post-processing one sheet, and then to the conveyance path B and the shift tray 202 which are led to the upper tray 201. The branching claw 15 and the branching claw 16 are configured to distribute to the conveyance path C that leads to the conveyance path D that leads to the conveyance path C that guides and the processing tray F that performs alignment and stapling (hereinafter also referred to as a staple processing tray).

  The image forming apparatus PR includes an image processing circuit that converts input image data into printable image data, although not shown, and an optical writing device that performs optical writing on a photoconductor based on an image signal output from the image processing circuit A developing device for developing toner on a latent image formed on a photosensitive member by optical writing, a transfer device for transferring a toner image visualized by the developing device to a sheet, and a fixing device for fixing the toner image transferred on the sheet At least the paper on which the toner image is fixed is sent to the paper post-processing device PD, and desired post-processing is performed by the paper post-processing device PD. Here, the image forming apparatus PR is of an electrophotographic system as described above, but any known image forming apparatus such as an ink jet system or a thermal transfer system can be used. In this embodiment, the image processing circuit, the optical writing device, the developing device, the transfer device, and the fixing device constitute an image forming unit.

  The paper guided to the staple processing tray F through the transport paths A and D, and aligned and stapled in the staple processing tray is guided to the shift tray 202 by the branch guide plate 54 and the movable guide 55 which are deflecting means. The sheet is configured to be distributed to a path C, a processing tray G that performs folding or the like (hereinafter also referred to as a middle folding processing tray). Led to. Further, a branching claw 17 is disposed in the conveyance path D, and is held in the state shown in the figure by a low load spring (not shown). After the trailing edge of the sheet passes through this, the conveyance rollers 9, 10 and the staple discharge roller 11 is configured such that at least the transport roller 9 is reversed to guide and stay at the rear end to the paper storage unit E, and can be transported while superposed on the next paper. By repeating this operation, it is possible to convey two or more sheets in a superimposed manner.

  In the conveyance path A common to the upstream of the conveyance path B, the conveyance path C, and the conveyance path D, an inlet sensor 301 that detects a sheet received from the image forming apparatus PR, an inlet roller 1, a punch unit 100, The punch and waste hopper 101, the conveying roller 2, the branching claw 15, and the branching claw 16 are sequentially arranged. The branch claw 15 and the branch claw 16 are held in the state shown in FIG. 1 by a spring (not shown), and when the solenoid (not shown) is turned on, the branch claw 15 rotates upward and the branch claw 16 rotates downward. The paper is distributed to the conveyance path B, the conveyance path C, and the conveyance path D.

  When guiding the paper to the conveyance path B, the branching claw 15 is in the state of FIG. 1 and the solenoid is OFF. When guiding the paper to the conveyance path C, the branching claw 15 is turned on by turning on the solenoid from the state of FIG. When the paper is guided to the transport path D, the branch claw 16 is in the state of FIG. 1, the solenoid is OFF, and the branch claw 15 is in the state of FIG. By turning on the solenoid, the solenoid is turned upward.

  In this paper post-processing apparatus, punching (punching unit 100), paper alignment + edge binding (jogger fence 53, edge binding stapler S1), paper alignment + saddle stitching (jogger fence 53, saddle stitching stapler) is performed on the paper. S2), paper sorting (shift tray 202), center folding (folding plate 74, folding rollers 81, 82), and the like can be performed.

2. Shift Tray Unit The shift tray paper discharge unit I located at the most downstream portion of the paper post-processing apparatus PD includes a shift paper discharge roller 6, a return roller 13, a paper surface detection sensor 330, a shift tray 202, and FIG. The shift mechanism J shown in FIG. 3 and the shift tray lifting mechanism K shown in FIG. 2 is an enlarged perspective view of the main part showing details of the shift mechanism J, and FIG. 3 is an enlarged perspective view of the main part of the shift tray lifting mechanism K.

  1 and 3, reference numeral 13 denotes a sponge roller for contacting the paper discharged from the shift paper discharge roller 6 and aligning the rear end of the paper against the end fence 32 shown in FIG. The return roller 13 is rotated by the rotational force of the shift paper discharge roller 6. A tray lift limit switch 333 is provided in the vicinity of the return roller 13, and when the shift tray 202 is lifted to push up the return roller 13, the tray lift limit switch 333 is turned on and the tray lifting / lowering motor 168 is stopped. Thereby, overrun of the shift tray 202 is prevented. Further, as shown in FIG. 1, a paper surface detection sensor 330 is provided in the vicinity of the return roller 13 as paper surface position detecting means for detecting the paper surface position of the paper discharged on the shift tray 202 or the sheet bundle. Yes.

  Although not shown in detail in FIG. 1, the paper surface detection sensor 330 includes the paper surface detection lever 30 shown in FIG. 3, a paper surface detection sensor (for stippling) 330a, and a paper surface detection sensor (for non-stipple) 330b. Yes. The paper surface detection lever 30 is provided so as to be rotatable about the shaft portion of the lever, and includes a contact portion 30 a that contacts the upper surface of the rear end of the paper loaded on the shift tray 202 and a fan-shaped shielding portion 30 b. The paper surface detection sensor (for stippling) 330a located above is mainly used for staple discharge control, and the paper surface detection sensor (for non-stipple) 330b is mainly used for shift discharge control.

  In the present embodiment, the paper surface detection sensor (for stipple) 330a and the paper surface detection sensor (for non-stipple) 330b are turned on when blocked by the shielding portion 30b. Therefore, when the shift tray 202 is raised and the contact portion 30a of the paper surface detection lever 30 is rotated upward, the paper surface detection sensor (for stippling) 330a is turned off, and when further rotated, the paper surface detection sensor (for non-stipple) 330b is turned on. To do. When it is detected by the paper surface detection sensor (for stipple) 330a and the paper surface detection sensor (for non-stipple) 330b that the sheet stacking amount has reached a predetermined height, the shift tray 202 is driven by the tray lift motor 168 to a predetermined amount. Descend. Thereby, the paper surface position of the shift tray 202 is kept substantially constant.

2.1 Shift Tray Lifting Mechanism The shift tray lifting mechanism will be described in detail.

  As shown in FIG. 3, the shift tray 202 moves up and down when the drive shaft 21 is driven by the drive unit L. A timing belt 23 is stretched between the drive shaft 21 and the driven shaft 22 via a timing pulley, and a side plate 24 that supports the shift tray 202 is fixed to the timing belt 23. With this configuration, the unit including the shift tray 202 is suspended from the timing belt 23 so as to be able to move up and down.

  The drive unit L is composed of a tray lifting / lowering motor 168 and a worm gear 25, and the power generated by the tray lifting / lowering motor 168 capable of forward / reverse rotation as a driving source is a gear train fixed to the driving shaft 21 via the worm gear 25. The shift gear 202 is moved in the vertical direction by being transmitted to the final gear. Since the power transmission system is via the worm gear 25, the shift tray 202 can be held at a fixed position, and this gear configuration can prevent an accidental drop accident of the shift tray 202 and the like.

  A shielding plate 24a is integrally formed on the side plate 24 of the shift tray 202, and a fullness detection sensor 334 for detecting the full load of stacked sheets and a lower limit sensor 335 for detecting a lower limit position are disposed below the shielding plate 24a. Thus, the fullness detection sensor 334 and the lower limit sensor 335 are turned on / off. The fullness detection sensor 334 and the lower limit sensor 335 are photosensors, and are turned on when blocked by the shielding plate 24a. In FIG. 3, the shift paper discharge roller 6 is omitted.

  As shown in FIG. 2, the swing mechanism of the shift tray 202 includes a shift motor 169 and a shift cam 31. By rotating the shift cam 31 using the shift motor 169 as a drive source, the shift tray 202 can eject paper. Reciprocates in a direction perpendicular to the direction. A pin 31 a is set up on the shift cam 31 at a position away from the center of the rotation shaft, and the other end of the pin 31 a is loosely fitted in the elongated hole 32 b of the engagement member 32 a of the end fence 32. The engaging member 32a is fixed to the back surface of the end fence 32 (the surface on which the shift tray 202 is not located) and reciprocates in a direction perpendicular to the paper discharge direction according to the rotational position of the pin 31a of the shift cam 31. As a result, the shift tray 202 also moves in a direction perpendicular to the paper discharge direction. The shift tray 202 stops at two positions on the front side and the back side in FIG. 1 (corresponding to an enlarged view of the shift cam 31 in FIG. 2), and the stop control detects the notch of the shift cam 31 by the shift sensor 336. This is performed by controlling the shift motor 169 on and off based on the detection signal.

  On the front side of the end fence 32, a guide protrusion 32c for the shift tray 202 is provided, and the rear end portion of the shift tray 202 is loosely fitted to the protrusion 32c so as to freely move up and down. 202 is supported by the end fence 32 so that it can move up and down and can reciprocate in a direction perpendicular to the paper transport direction. The end fence 32 has a function of guiding the trailing edge of the loaded paper on the shift tray 202 and aligning the trailing edges.

2.2 Paper Discharge Unit FIG. 4 is a perspective view showing the structure of the paper discharge unit to the shift tray 202.

  1 and 4, the shift paper discharge roller 6 has a driving roller 6a and a driven roller 6b. The driven roller 6b is supported on the upstream side in the paper discharge direction and is provided with an open / close guide plate that can swing up and down. 33 is rotatably supported at the free end portion. The driven roller 6b abuts on the driving roller 6a by its own weight or urging force, and the paper is nipped between the rollers 6a and 6b and discharged. When the bound sheet bundle is discharged, the open / close guide plate 33 is pulled upward and returned at a predetermined timing. This timing is determined based on the detection signal of the shift paper discharge sensor 303. Is done. The stop position is determined based on the detection signal of the paper discharge guide plate opening / closing sensor 331 and is driven by the paper discharge guide plate opening / closing motor 167. The discharge guide plate opening / closing motor 167 is driven and controlled by turning on / off a discharge guide plate opening / closing limit switch 332.

3. Stipple Processing Tray 3.1 Overall Configuration of Stipple Processing Tray A configuration of a stipple processing tray F that performs stipple processing will be described in detail.

  FIG. 5 is a plan view of the staple processing tray F viewed from a direction perpendicular to the sheet conveying surface, FIG. 6 is a perspective view showing the staple processing tray F and its driving mechanism, and FIG. 7 is a perspective view showing the sheet bundle discharging mechanism. It is. First, as shown in FIG. 6, the sheets guided to the staple processing tray F by the staple discharge roller 11 are sequentially stacked on the staple processing tray F. In this case, alignment in the vertical direction (paper conveyance direction) is performed by the tapping roller 12 for each sheet, and alignment in the horizontal direction (direction perpendicular to the sheet conveyance direction—also referred to as the sheet width direction) is performed by the jogger fence 53. The end-face stitching stapler S1 is driven by a staple signal from the control device 350 (see FIG. 23) between job breaks, that is, between the last sheet of the sheet bundle and the first sheet of the next sheet bundle, and the binding process is performed. The sheet bundle subjected to the binding process is immediately sent to the shift paper discharge roller 6 by the discharge belt 52 with the discharge claw 52a protruding, and is discharged to the shift tray 202 set at the receiving position.

3.2 Paper Discharge Mechanism As shown in FIG. 7, the discharge claw 52 a has its home position detected by the discharge belt HP sensor 311, and this discharge belt HP sensor 311 is provided on the discharge belt 52. The discharge claw 52a is turned on / off. Two discharge claws 52a are arranged at opposing positions on the outer periphery of the discharge belt 52, and the sheet bundle stored in the staple processing tray F is moved and conveyed alternately. Further, if necessary, the discharge belt 52 is rotated in the reverse direction, and the sheet bundle stored in the staple processing tray F on the back side of the discharge claw 52a and the discharge claw 52a 'on the opposite side waiting to move the sheet bundle. It is also possible to align the tips in the transport direction. Therefore, the discharge claw 52a also functions as a means for aligning the sheet bundle in the sheet conveyance direction.

  Further, as shown in FIG. 5, the discharge belt 52 driven by the discharge motor 157 has a discharge belt 52 and its drive pulley 62 arranged at the alignment center in the paper width direction with respect to the drive pulley 62. The discharge roller 56 is arranged and fixed symmetrically. Further, the peripheral speed of these discharge rollers 56 is set to be higher than the peripheral speed of the discharge belt 52.

3.3 Processing Mechanism As shown in FIG. 6, the hitting roller 12 is given a pendulum motion by a hitting SOL (solenoid) 170 around a fulcrum 12a, and acts intermittently on the paper fed to the staple processing tray F. The sheet is abutted against the rear end fence 51. The hitting roller 12 rotates counterclockwise.

  The jogger fence 53 is driven via a timing belt by a jogger motor 158 capable of forward and reverse rotation, and reciprocates in the paper width direction.

  As can be seen from the perspective view showing the stapler S1 of FIG. 8 together with the moving mechanism, the end-face stitching stapler S1 is driven via a timing belt by a forward / reversely movable stapler moving motor 159 to bind a predetermined position of the sheet end. Move in the paper width direction. A stapler movement HP sensor 312 for detecting the home position of the end face binding stapler S1 is provided at one end of the moving range, and the binding position in the paper width direction is the amount of movement of the end face binding stapler S1 from the home position. Controlled by Further, as shown in the perspective view of FIG. 9, the end-face stitching stapler S1 is configured to change only the stitching mechanism portion of the stapler S1 at the home position so that the needle driving angle can be changed parallel to or obliquely with respect to the sheet edge. It is configured so that the staple needle can be easily exchanged by rotating at an angle. The stapler S1 is rotated obliquely by the oblique motor 160, and when the needle replacement position sensor 313 detects that the needle replacement position sensor 313 reaches a predetermined oblique angle or the needle replacement position, the oblique motor 160 stops. When the diagonal strike is finished or the needle exchange is finished, the original position is rotated to prepare for the next staple.

  As shown in FIGS. 1 and 5, the saddle stitching stapler S2 is a distance in which the distance from the rear end fence 51 to the needle striking position of the saddle stitching stapler S2 corresponds to half of the conveyance direction length of the maximum sheet size that can be saddle stitched. The two are arranged as described above, and two are arranged symmetrically with respect to the alignment center in the paper width direction, and are fixed to the stay 63. Since the saddle stitching stapler S2 itself is a known configuration, a detailed description thereof will be omitted here. However, when performing saddle stitching, the jogger fence 53 aligns the direction perpendicular to the sheet conveyance direction and strikes the trailing edge fence 51. After the conveyance direction of the sheet is aligned by the roller 5, the discharge belt 52 is driven and the trailing end of the sheet bundle is lifted by the discharge claw 52, and the central portion in the conveyance direction of the sheet bundle is located at the binding position of the saddle stitching stapler S2. And then stop at this position to execute the binding operation. Then, the bound sheet bundle is conveyed to the middle folding processing tray G side and folded in half. Details will be described later.

  In the figure, reference numeral 64a denotes a front side plate, 64b denotes a rear side plate, and reference numeral 310 denotes a paper presence / absence sensor that detects the presence / absence of paper on the staple processing tray F.

4). Sheet Bundle Deflection Mechanism The sheet bundle that has been saddle-stitched in the staple processing tray F is folded in the middle of the sheet. This middle folding is performed in the middle folding processing tray G. For this purpose, it is necessary to transport the bound sheet bundle to the middle folding processing tray G. In this embodiment, a sheet bundle deflecting unit is provided on the most downstream side in the conveyance direction of the staple processing tray F, and conveys the sheet bundle to the middle folding processing tray G side. The sheet bundle deflection mechanism includes a branch guide plate 54 and a movable guide 55 as shown in the enlarged views of the staple processing tray F and the middle folding processing tray G in FIGS. As shown in the operation explanatory diagrams of FIGS. 10 to 12, the branch guide plate 54 is provided so as to be swingable in the vertical direction around the fulcrum 54 a, and a rotatable pressure roller 57 is provided on the downstream side thereof. The pressure is applied to the discharge roller 56 side. Further, the position of the branch guide plate 54 is defined by the contact position with the cam surface 61 a of the cam 61 that rotates by obtaining a driving force from the bundle branch drive motor 161.

  The movable guide 55 is swingably supported on the rotation shaft of the discharge roller 56, and is linked to one end of the movable guide 55 (the end opposite to the branch guide plate 54) by a connecting portion 60a. An arm 60 is provided. The link arm 60 includes a shaft fixed to the front side plate 64a shown in FIG. 5 and a long hole portion 60b, whereby the swing range of the movable guide 55 is restricted. Further, it is held at the position shown in FIG. Further, when the link arm 60 is pushed by the cam surface 61b of the cam 61 that rotates by obtaining drive from the bundle branching drive motor 161, the connected movable guide 55 rotates upward. The bundle branching guide HP sensor 315 detects the shield 61c of the cam 61 and detects the home position of the cam 61. Accordingly, the cam 61 controls the stop position by counting the drive pulses of the bundle branching drive motor 161 with the home position as a reference.

  FIG. 10 is an operation explanatory view showing the positional relationship between the branch guide plate 54 and the movable guide 55 when the cam 61 is located at the home position. The guide surface 55 a of the movable guide 55 has a function of guiding the paper in the path to the shift paper discharge roller 6.

  In FIG. 11, as the cam 61 rotates, the branch guide plate 54 rotates counterclockwise (downward) in the drawing around the fulcrum 54a, and the pressure roller 57 contacts and presses the discharge roller 56 side. It is an operation explanatory view showing the state.

  In FIG. 12, when the cam 61 further rotates, the movable guide 55 rotates in the clockwise direction (upward) in the figure, and the path leading from the staple processing tray F to the half-fold processing tray G is guided along the branch guide plate 54 and the movable guide. FIG. FIG. 5 shows the positional relationship in the depth direction.

  In this embodiment, the branch guide plate 54 and the movable guide 55 are operated by a single drive motor. However, each drive motor is provided so that the movement timing and stop position can be controlled according to the paper size and the number of sheets to be bound. You may do it.

5. 5. Middle Folding Tray 5.1 Configuration of Each Part FIGS. 13 and 14 are operation explanatory views of the moving mechanism of the folding plate 74 for performing the middle folding.

  The folding plate 74 is supported by loosely fitting the long hole portions 74 a to the two shafts 64 c erected on the front and rear side plates 64 a and 64 b, and the shaft portion 74 b erected from the folding plate 74 is further linked to the link arm 76. When the link arm 76 swings about the fulcrum 76a, the folding plate 74 reciprocates left and right in FIG. 13 and FIG. That is, the shaft portion 75b of the folding plate driving cam 75 is loosely fitted in the long hole portion 76c of the link arm 76, and the link arm 76 swings due to the rotational movement of the folding plate driving cam 75. 15, the folding plate 74 reciprocates in a direction perpendicular to the upper and lower bundle conveyance guide plates 91 and 92.

  The folding plate driving cam 75 is rotated in the direction of the arrow in FIG. 13 by the folding plate driving motor 166. The stop position is determined by detecting both end portions of the half-moon shaped shielding portion 75a by the folding plate HP sensor 325.

  FIG. 13 shows the home position position completely retracted from the sheet bundle accommodation area of the processing tray G. When the folding plate drive cam 75 is rotated in the direction of the arrow, the folding plate 74 moves in the direction of the arrow and protrudes into the sheet bundle accommodation area of the processing tray G. FIG. 14 shows a position where the center of the sheet bundle of the processing tray G is pushed into the nip of the folding roller 81. When the folding plate drive cam 75 is rotated in the direction of the arrow, the folding plate 74 moves in the direction of the arrow and retracts from the sheet bundle accommodation area of the processing tray G.

  In this embodiment, it is assumed that the sheet folding is performed by folding the sheet bundle. However, the present invention can be applied to the case of folding one sheet. In this case, saddle stitching is not required for only one sheet, so when one sheet is discharged, the sheet is fed to the middle folding processing handle G side, folded by the folding plate 74 and the folding roller, and discharged to the lower tray. To do.

6). Control Device As shown in FIG. 16, the control device 350 is composed of a microcomputer having a CPU 360, an I / O interface 370, etc., and each switch of the control panel of the image forming apparatus PR main body, the inlet sensor 301, and the upper paper discharge. Sensor 302, shift paper discharge sensor 303, pre-stack sensor 304, staple paper discharge sensor 305, paper presence sensor 310, discharge belt home position sensor 311, staple movement home position sensor 312, stapler oblique home position sensor 313, jogger fence home position Sensor 314, bundle branch guide home position sensor 315, bundle arrival sensor 321, movable rear end fence home position sensor 322, folding section passage sensor 323, lower sheet discharge sensor 324, folding plate Signals from various sensors such as the image position sensor 325, the paper surface detection sensors 330, 330 a, and 330 b and the paper discharge guide plate opening / closing sensor 331 are input to the CPU 360 via the I / O interface 370.

  The CPU 360 drives the tray lifting / lowering motor 168 for the shift tray 202, the discharge guide plate opening / closing motor 167 for opening / closing the opening / closing guide plate, the shift motor 169 for moving the shift tray 202, and the tapping roller 12 based on the input signal. The unillustrated tapping roller motor, solenoids such as tapping SOL 170, a conveying motor for driving each conveying roller, a discharging motor for driving each discharging roller, a discharging motor 157 for driving the discharging belt 52, and an end face binding stapler S1 are moved. The stapler moving motor 159, the oblique motor 160 that obliquely rotates the end-face stitching stapler S1, the jogger motor 158 that moves the jogger fence 53, the bundle branch drive motor 161 that rotates the branch guide plate 54 and the movable guide 55, and the bundle is conveyed. (Not shown) Conveying motor, the rear end fence moving motor, the folding moves the folding plate 74 plate drive motor 166 (not shown) for moving the movable rear fence 73, and controls the driving such as the folding roller drive motor (not shown) that drives the folding rollers 81. A pulse signal of a not-shown staple conveyance motor that drives the staple discharge roller is input to the CPU 360 and counted, and the hitting SOL 170 and the jogger motor 158 are controlled according to this count.

  The punch unit 100 also performs drilling according to instructions from the CPU 360 by controlling the clutch and the motor.

  The sheet post-processing device PD is controlled by the CPU 360 executing a program written in a ROM (not shown) while using a RAM (not shown) as a work area.

7). Operation The operation of the sheet post-processing apparatus according to the present embodiment executed by the CPU 360 will be described below.

7.1 Operation According to Processing Mode In this embodiment, the following discharge mode is adopted according to the post-processing mode.

(1) Non-stipple mode A:
In this mode, the sheet is discharged from the conveyance path A through the conveyance path B to the upper tray 201 without binding. In this mode, the branching claw 15 rotates clockwise in FIG. 1, and the conveyance path B side is opened. The processing procedure at this time is shown in the flowchart of FIG.

  In this mode, when the operation is started and the sheet is brought in from the image forming apparatus PR side, the entrance roller 1 and the transport roller 2 of the transport path A of the sheet post-processing apparatus PD, the transport roller 3 of the transport path B, and Each of the upper paper discharge rollers 4 starts to rotate (step S101). Then, the entrance sensor 301 is turned on / off (steps S102, S103) and the upper paper discharge sensor 302 is turned on / off (steps S104, S105) to confirm the passage of the sheet, and the final sheet passes (step). S107) When a predetermined time has elapsed, the rotation of the rollers, that is, the entrance roller 1, the transport roller 2, the transport roller 3, and the upper paper discharge roller 4 is stopped. As a result, all the sheets carried in from the image forming apparatus PR are discharged and stacked on the upper tray 201 without being bound. In this embodiment, since the punch unit 100 is provided between the entrance roller 1 and the transport roller 2, the punch unit 100 can also make a hole between them.

(2) Non-stipple mode B:
In this mode, the sheet is discharged from the conveyance path A to the shift tray 202 via the conveyance path C without binding the sheets. In this mode, the branch claw 15 rotates counterclockwise and the branch claw 16 rotates clockwise, and the conveyance path C is opened. The processing procedure at this time is shown in the flowchart of FIG.

  In this mode, when the operation is started and the sheet is brought in from the image forming apparatus PR side, the entrance roller 1 and the transport roller 2 in the transport path A of the sheet post-processing apparatus PD, the transport roller 5 in the transport path C, and Each of the shift paper discharge rollers 6 starts to rotate (step S201). Then, the solenoid that drives the branch claws 15 and 16 is turned on (step S202), and the branch claws 15 are rotated counterclockwise and the branch claws 16 are rotated clockwise. Next, the entrance sensor 301 is turned on and off (steps S203 and S204) and the shift paper discharge sensor 303 is turned on and off (steps S205 and S206) to check the passage of the loaded paper.

  When the final sheet passes (step S207) and a predetermined time elapses, the rotation of each of the rollers, that is, the entrance roller 1, the conveyance roller 2, the conveyance roller 5, and the shift discharge roller 6 is stopped (step S208). The solenoid that drives the branch claws 15 and 16 is turned off (step S209). As a result, all the sheets carried in from the image forming apparatus PR are discharged and stacked on the shift tray 202 without being bound. In this embodiment, since the punch unit 100 is provided between the entrance roller 1 and the transport roller 2, the punch unit 100 can also make a hole between them.

(3) Sort, stack mode:
In this mode, the sheet is discharged from the conveyance path A to the shift tray 202 via the conveyance path C. At this time, the shift tray 202 is swung in a direction orthogonal to the sheet discharge direction at every section separation, In this mode, the sheets discharged onto the shift tray 202 are sorted. In this mode, similarly to the non-stipple mode B, the branching claw 15 rotates counterclockwise and the branching claw 16 rotates clockwise, and the conveyance path C is opened. The processing procedure at this time is shown in the flowchart of FIG.

  In this mode, when the operation is started and the sheet is brought in from the image forming apparatus PR side, the entrance roller 1 and the transport roller 2 in the transport path A of the sheet post-processing apparatus PD, the transport roller 5 in the transport path C, and Each of the shift paper discharge rollers 6 starts to rotate (step S301). Then, the solenoid for driving the branch claws 15 and 16 is turned on (step S302), and the branch claws 15 are rotated counterclockwise and the branch claws 16 are rotated clockwise. Then, it is checked whether the entrance sensor 301 is on or off (steps S303 and S304) and the shift paper discharge sensor 303 is on (step S305).

  As a result of this check, if the paper that has passed through the shift paper discharge sensor 303 is the first paper in the set (step S306-Y), the shift motor 169 is turned on (step S307), and the shift sensor 336 detects the shift tray 202. The shift tray 202 is moved in the direction orthogonal to the sheet conveyance direction (step S309). Then, the paper is discharged to the shift tray 202, the shift paper discharge sensor 303 is turned off, and when the paper is confirmed to pass through the shift paper discharge sensor 303 (step S310), it is checked whether the paper is the final paper. (Step S311). If it is not the final sheet, it is the first sheet in this case, so if it is not one sheet, the process returns to step S303 and the subsequent processing is repeated. If the section is composed of one sheet, the process of step S312 is executed. To do. On the other hand, if the paper that has passed through the shift paper discharge sensor 303 in step S306 is not the first paper in the copy, the shift tray 202 has already moved, and the paper is discharged as it is (step S310). It is checked whether it is paper (step S311). If it is not the final sheet, the processing from step S303 is repeated on the next sheet. If it is the final sheet (step S311-Y), the rollers, Then, the rotation of the entrance roller 1, the transport roller 2, the transport roller 5, and the shift paper discharge roller 6 is stopped (step S312), and the solenoid that drives the branch claws 15 and 16 is turned off (step S313). As a result, all sheets carried in from the image forming apparatus PR are discharged to the shift tray 202 without being bound, sorted, and stacked. In this case as well, the sheets punched by the punch unit 100 can be sorted and stacked.

(4) Stipple mode:
In this mode, the sheet is transported to the staple processing tray F through the transport path A and the transport path D, and after alignment and binding processing is performed on the staple processing tray F, the sheet is discharged to the shift tray 202 through the transport path C. It is. In this mode, both the branch claw 15 and the branch claw 16 rotate counterclockwise, and the path from the transport path A to D is opened. The processing procedure at this time is shown in FIG.

  In this mode, when the operation is started and the sheet is brought in from the image forming apparatus PR side PR, the entrance roller 1 and the transport roller 2 of the transport path A of the sheet post-processing apparatus PD, and the transport roller 7 of the transport path D , 9, 10 and the staple discharge roller 11 and the hitting roller 12 of the staple processing tray F start to rotate (step S401). Then, the solenoid that drives the branch claw 15 is turned on (step S402), and the branch claw 15 is rotated counterclockwise.

  Next, the end surface binding stapler S1 is detected by the stapler movement HP sensor 312, and after confirming the home position, the stapler movement motor 159 is driven to move the end surface binding stapler S1 to the binding position (step S403). The home position of the discharge belt 52 is also detected by the discharge belt HP sensor 311, and after confirming the position, the discharge motor 157 is driven to move the discharge belt 52 to the standby position (step S404). Further, the jogger fence 53 is also moved to the standby position after the home position position is detected by the jogger fence HP sensor (step S405). Further, the branch guide plate 54 and the movable guide 55 are moved to the home position (step S406).

  If the entrance sensor 301 is turned on / off (steps S407 and S408), the staple paper discharge sensor 305 is turned on (step S409), and the shift paper discharge sensor 303 is turned off (step S410), paper is loaded on the staple processing tray F. Since the sheet is discharged and the sheet is present, the tapping solenoid 170 is turned on for a predetermined time, the tapping solenoid 12 is brought into contact with the sheet, and is urged toward the rear end fence 51 to align the rear end of the sheet (step S411). . Next, the jogger motor 158 is driven to move the jogger fence 53 inward by a predetermined amount to perform the alignment operation in the paper width direction (direction perpendicular to the paper transport direction), and then return to the standby position (step S412). . As a result, the vertical and horizontal directions of paper fed to the staple processing tray F (the direction perpendicular to the direction parallel to the transport direction) are aligned. The operations from step S407 to step S413 are repeated for each sheet, and when the final sheet of the sheet is reached (step S413-Y), the jogger fence 53 is moved inward by a predetermined amount so that the sheet end face is not displaced (step S414). In this state, the end face binding stapler S1 is turned on to execute the end face binding (step S415).

  On the other hand, the shift tray 202 is lowered by a predetermined amount (step S416) to secure a paper discharge space, the shift paper discharge motor is driven to start the rotation of the shift paper discharge roller 6 (step S417), and the discharge motor 157 is further turned on. The discharge belt 52 is turned on and rotated by a predetermined amount (step S418), and the bound sheet bundle is pushed up in the direction of the conveyance path C. As a result, the sheet bundle is sandwiched between the nips of the shift sheet discharge roller 6 and the sheet discharge operation to the shift tray 202 is performed. Then, the shift paper discharge sensor 303 is turned on (step S419), the sheet bundle enters the sensor 303 position, and it is confirmed that the shift paper discharge sensor 303 is turned off and the sheet bundle has passed the sensor 303 position. (Step S420), since the sheet bundle has been discharged to the shift tray by the shift discharge roller 6, the discharge belt 52 and the jogger fence 53 are moved to the standby position (Steps S421 and S422). Then, the rotation of the shift paper discharge roller 6 is stopped after a predetermined time (step S423), and the shift tray 202 is raised to the paper receiving position (step S424). This rising position is controlled by detecting the upper surface of the uppermost sheet of the stack of sheets stacked on the shift tray 202 by the paper surface detection sensor 330. These series of operations are repeated until the final part of the job (step S425).

  In the final part, the end-face stitching stapler S1, the discharge belt 52, and the jogger fence 53 are moved to their home positions (steps S426, S427, and S428), the entrance roller 1, the transport rollers 2, 7, 9, and 10, and the staples. The rotation of the discharge roller 11 and the hitting roller 12 is stopped (step S429), the branch solenoid of the branch claw 15 is turned off (step S430), and all the processing is returned to the initial state and the process is finished.

  In this manner, the sheets carried in from the image forming apparatus PR are bound by the staple processing tray F, discharged onto the shift tray 202, and stacked. In this case as well, the binding processing of the paper punched by the punch unit 100 is possible.

  The operation of the stipple processing tray F in the stipple mode will be described in more detail.

  When the stipple mode is selected, as shown in FIG. 6, the jogger fence 53 moves from the home position and waits at a standby position that is 7 mm away from the sheet width discharged to the staple processing tray F (step S405). . When the paper is conveyed by the staple paper discharge roller 11 and the rear end of the paper passes through the staple paper discharge sensor 305 (step S409), the jogger fence 53 moves inward by 5 mm from the standby position and stops.

  Further, the staple paper discharge sensor 305 detects that when the trailing edge of the paper passes, and the signal is input to the CPU 360. The CPU 360 counts the number of pulses transmitted from a not-shown staple transport motor that drives the staple paper discharge roller 11 from the time of receiving this signal, and hits the SOL 170 after transmitting a predetermined pulse (step S412). The tapping roller 12 performs a pendulum motion by turning on and off the tapping SOL 170. When the tapping roller 12 is on, the tapping roller 12 strikes the paper and returns it to the lower side, and abuts against the rear end fence 51 to align the paper. At this time, every time a sheet stored in the staple processing tray F passes the entrance sensor 301 or the staple discharge sensor 305, the signal is input to the CPU 360, and the number of sheets is counted.

  After a lapse of a predetermined time after the beating SOL 170 is turned off, the jogger fence 53 is further moved inward by 2.6 mm by the jogger motor 158, temporarily stops, and the horizontal alignment is finished. The jogger fence 53 then moves outward by 7.6 mm, returns to the standby position, and waits for the next sheet (step S412). This operation is performed up to the last page (step S413). After that, it moves again inward by 7 mm and stops (step S414), and both sides of the sheet bundle are pressed to prepare for the stapling operation. Thereafter, after a predetermined time, the end face binding stapler S1 is actuated by a staple motor (not shown), and the binding process is performed (step S415). If two or more bindings are designated at this time, after one binding process is completed, the staple movement motor 159 is driven, and the end face binding stapler S1 is moved to an appropriate position along the rear edge of the sheet. The second stitching process is performed. If the third and subsequent locations are specified, this is repeated.

  When the binding process is completed, the discharge motor 157 is driven, and the discharge belt 52 is driven (step S418). At this time, the paper discharge motor is also driven, and the shift paper discharge roller 6 starts to rotate so as to accept the sheet bundle lifted by the discharge claw 52a (step S417). At this time, the jogger fence 53 is controlled differently based on the paper size and the number of sheets to be bound. For example, when the number of sheets to be bound is less than the set number or smaller than the set size, the trailing edge of the sheet bundle is hooked and conveyed by the discharge claw 52a while the sheet bundle is pressed by the jogger fence 53.

  Then, after a predetermined pulse from the detection by the paper presence sensor 310 or the discharge belt HP sensor 311, the jogger fence 53 is retracted by 2 mm, and the restriction on the paper by the jogger fence 53 is released. This predetermined pulse is set after the discharge claw 52a comes into contact with the rear end of the paper and passes through the front end of the jogger fence 53.

  When the number of sheets to be bound is larger than the set number or larger than the set size, the jogger fence 53 is retracted in advance by 2 mm and discharged. In any case, when the sheet bundle passes through the jogger fence 53, the jogger fence 53 further moves outward by 5 mm and returns to the standby position (step S422) to prepare for the next sheet. It is also possible to adjust the binding force according to the distance of the jogger fence 53 to the paper.

(5) Saddle binding mode:
In this mode, the sheet is conveyed to the staple processing tray F via the conveyance path A and the conveyance path D, and after alignment and center binding are performed in the staple processing tray F, the sheet is further folded in the middle folding processing tray G and then folded in half. In this mode, the sheet bundle is discharged to the lower tray 203 through the conveyance path H. In this mode, both the branch claw 15 and the branch claw 16 rotate counterclockwise, and the path from the transport path A to D is opened. Further, the branch guide plate 54 and the movable guide plate 55 are closed as shown in FIG. 24 to be described later, and the sheet bundle is guided to the middle folding processing tray G, and the middle folding is performed. The processing procedure at this time is shown in FIG.

  In this mode, when the operation is started and the sheet is brought into the state from the image forming apparatus PR side, the entrance roller 1 and the conveyance roller 2 of the conveyance path A of the sheet post-processing apparatus PD, the conveyance roller 7 of the conveyance path D, 9, 10 and the staple discharge roller 11 and the hitting roller 12 of the staple processing tray F start to rotate (step S501). Then, the solenoid for driving the branch claw 15 is turned on (step S502), and the branch claw 15 is rotated counterclockwise.

  Next, the home position of the discharge belt 52 is also detected by the discharge belt HP sensor 311, and after confirming the position, the discharge motor 157 is driven to place the discharge belt 52 in the standby position, and the jogger fence 53 is also a jogger fence HP sensor. After detecting the home position, the branch guide plate 54 and the movable guide 55 are further moved to the home position, respectively, to the standby position (steps S503, S504, and S505).

  If the entrance sensor 301 is turned on / off (steps S506 and S507), the staple paper discharge sensor 305 is turned on (step S508), and the shift paper discharge sensor 303 is turned off (step S509), the paper is loaded on the staple processing tray F. Since the sheet is ejected and the sheet is present, the tapping solenoid 170 is turned on for a predetermined time, the tapping solenoid 12 is brought into contact with the sheet, and urged toward the rear end fence 51 to align the rear end of the sheet (step S510). . Next, by driving the jogger motor 158, the jogger fence 53 is moved inward by a predetermined amount to perform the aligning operation in the paper width direction (direction orthogonal to the paper transport direction), and then returned to the standby position (step S511). . As a result, the vertical and horizontal directions of paper fed to the staple processing tray F (the direction perpendicular to the direction parallel to the transport direction) are aligned.

  These operations from step S506 to step S512 are repeated for each sheet, and when the final sheet of the copy is obtained (step S512-Y), the jogger fence 53 is moved inward by a predetermined amount so that the end face of the sheet does not shift (step S513). In this state, the discharge motor 157 is turned on to rotate the discharge belt 52 by a predetermined amount (step S514), and the sheet bundle is raised to the binding position of the saddle stitching stapler S2. Then, the saddle stitching stapler S2 is turned on at the center of the sheet bundle, and saddle stitching is performed (step S515). Next, the branch guide plate 54 and the movable guide 55 are displaced by a predetermined amount to form a path toward the center folding processing tray G (step S516), and rotation of the lower 71 and 72 on the bundle conveying rollers of the center folding processing tray G is performed. Is started, and the home position of the movable rear end fence 73 provided in the middle folding processing tray G is detected, and then the movable rear end fence 73 is moved to the standby position.

  In this way, when the sheet bundle receiving system of the half-fold processing tray G is prepared, the discharge belt 52 is further rotated by a predetermined amount (step S519) and added to the discharge roller 56 and the pressure roller 57 to perform the middle folding process. The sheet bundle is conveyed to the tray G side. When the leading edge of the sheet reaches the bundle arrival sensor 321 position (step S520) and is conveyed for a predetermined distance, the rotation of the upper and lower portions 71 and 72 on the bundle conveyance roller is stopped (step S521), and the pressure state of the lower bundle conveyance roller 72 is released. (Step S522). Next, the folding operation by the folding plate 74 is started (step S523), and the rotation of the folding rollers 81 and 82 and the lower paper discharge roller 83 is started (step S524). Then, the passage of the sheet bundle folded in half by the folding portion passage sensor 323 is monitored (steps S525 and S526). In this process, the following processing is executed.

  In the above-described step S525-2, the folding rollers 81 and 82 are stopped in a state where the leading end portion of the sheet bundle is sandwiched between the second folding rollers 82 and the intermediate portion is sandwiched between the first folding rollers 81, and the sheet bundles are respectively separated. (Refer to FIG. 31 described later). This enhances folding of the sheet bundle. When a predetermined time elapses in this state (YES in step S525-3), the first and second folding rollers 81 and 82 and the lower paper discharge roller 83 start to rotate and send out a sheet bundle (step S525-4). ), The processing after step S526 is executed.

  When the rear end of the sheet bundle passes through the position of the folding portion passage sensor 323 (step S526-Y), the lower bundle conveying roller 72 is pressurized (step S527), and the folding plate 74, the branch guide plate 54, and the movable guide plate 55 are brought home. Move to a position (steps S528 and S529).

  In this state, the passage of the sheet bundle is monitored by the lower sheet discharge sensor 324 (steps S530 and 531). When the rear end of the sheet bundle passes through the lower sheet discharge sensor 324 (step S531-Y), the folding rollers 81 and 82, The paper discharge roller 83 is further rotated for a predetermined time and then stopped (step S532). Next, the discharge belt 52 and the jogger fence 53 are moved to the standby position (steps S533 and S534). Then, it is checked whether or not it is the final part of the job (step S535). If it is not the final part of the job, the process returns to step S506 and the subsequent processing is repeated, and if it is the final part, the discharge belt 52 and the jogger fence 53 are set to the home position. (Steps S536, S537), the rotation of the entrance roller 1, the transport rollers 2, 7, 9, 10, the staple discharge roller 11 and the tapping roller 12 is stopped (step S538), and the branch solenoid of the branch claw 15 is turned off. It is turned off (step S539), and all the processes are returned to the initial state to finish the process.

  In this way, the sheets carried in from the image forming apparatus PR are saddle-stitched in the staple processing tray F, folded in the middle folding processing tray G, and then the sheet bundle folded in the lower tray 203 is discharged. To load.

8). Details of the binding operation and the folding operation in the middle folding mode The binding operation and the folding operation in the middle folding mode will be described in more detail.

  The paper sorted by the branching claw 15 and the branching claw 16 from the conveyance path A is guided to the conveyance path D and discharged to the staple processing tray F by the conveyance rollers 7, 9 and 10 and the staple discharge roller 11. In the stipple processing tray F, the sheets sequentially discharged by the discharge rollers 11 are aligned in the same manner as in the stipple mode (4), and the same operation is performed until just before the stipple (see FIG. 22). Thereafter, as shown in FIG. 23, the sheet bundle is conveyed downstream in the conveying direction by a distance set for each sheet size by the discharge claw 52a, and the center thereof is bound by the saddle stitching stapler S2. The bound sheet bundle is conveyed by a discharge claw 52a to the downstream side in the conveyance direction for a predetermined distance set for each sheet size, and temporarily stops. This moving distance is managed by the drive pulse of the discharge motor 157.

  Thereafter, as shown in FIG. 24, the leading end of the sheet bundle is sandwiched between the discharge roller 56 and the pressure roller 57, and the path formed by the rotation of the branch guide plate 54 and the movable guide 55, that is, the middle folding. The paper is again transported downstream by the discharge claw 52a and the discharge roller 56 so as to pass through the path guided to the processing tray G. The discharge roller 56 is provided on the drive shaft of the discharge belt 52 as described above, and is driven in synchronization with the discharge belt 52. 25 and 26, the sheet bundle is moved from the home position to a position corresponding to the sheet size in advance by the upper bundle conveying roller 71 and the lower bundle conveying roller 72, and the lower end face is guided. In order to do so, it is conveyed to the movable rear end fence 73 that is stopped. At this time, the discharge claw 52a stops at the position where the other discharge claw 52a ′ arranged at the position facing the outer periphery of the discharge belt 52 reaches the vicinity of the rear end fence 51, and the branch guide plate 54 and the movable guide 55 returns to the home position and prepares for the next sheet.

  As shown in FIG. 26, the sheet bundle abutted against the movable rear end fence 73 is released from the pressurization of the lower bundle conveyance roller 72, and then the vicinity of the stapled needle portion is folded as shown in FIG. The plate 74 is pushed in a substantially right angle direction and guided to the nip of the opposing folding roller 81. The first folding roller 81 rotating in advance folds the center of the sheet bundle by conveying the sheet bundle guided to the nip under pressure.

  Next, the leading end of the sheet bundle enters the nip portion of the second folding roller 83. Then, the sheet is discharged to the lower tray 203 by the lower discharge roller 83 as shown in FIG. At that time, the nip is opened to the first folding roller 81 as shown in FIG. At this time, when the rear end of the sheet bundle is detected by the folding portion passage sensor 323, the folding plate 74 and the movable rear end fence 73 are returned to the home position, and the pressurization of the lower bundle conveying roller 72 is also restored. Prepare for paper. If the next job is the same sheet size and the same number of sheets, the movable rear end fence 73 may stand by at that position.

30 to 31 are views showing a stacking state on the lower tray 203 of the saddle stitched sheet bundle shown in FIG.
In the stacking apparatus according to the present embodiment, as shown in FIG. 30, the pressure arm 501 has a spring hooking portion 501b, and the tension spring 503 as a pressure reducing means is on the side opposite to the side holding the sheet with respect to the rotation fulcrum 501a. The load is reduced by being hooked on the end and pulling the arm 501 clockwise in the figure. As a matter of course, if the arm 501 rotates around the rotation fulcrum 501a in the clockwise direction in the drawing, the attachment length of the tension spring 503 is shortened, the tension load is reduced, and the pressure applied to the pressure arm 501 is increased. Has been. In place of the tension spring 503, a torsion coil spring may be arranged on the rotating shaft passing through the rotation fulcrum 501a to perform the same operation.

  In the structure, the pressing force changes according to the rotation amount of the pressure arm 501. At this time, the pressing force decreases as the sheet stacking height of the stacking tray 203 is lower as described above.

  The pressure arm 501 has a rotation fulcrum 501 a on the upper side in the vicinity of the discharge roller 83, and is provided so as to be rotatable according to the height of the sheets stacked on the stacking tray 203. . Therefore, the distance between the contact point of the stacking tray 203 and the pressure arm 501 from the contact point to the discharge roller 83 is shorter than the length of the large size (B4 / 2: 182 mm or more) and the small size (A4 / 2: 148). (Sheets of 5 mm or less). That is, the length of the pressure arm 501 is set as shown in FIG. 31 in the case of small size loading and as shown in FIG. 32 in the case of large size loading. As a result, in the case of a small size, it can be loaded inside the pressure arm 501, and in the case of a large size, it can penetrate the pressure arm 501 and advance forward.

  Since the sheets are stacked in this way, when stacking small-sized sheets as shown in FIG. 31, the leading ends of the sheets stacked on the sheet leading-end guide surface 501d on the leading end side of the arm 501 toward the sheet passing side are formed in a platform shape. In order to load while shifting, the pressurizing arm 501 has an inclination angle extending in two stages and is formed in the shape of a letter “H”.

  Also, as shown in FIG. 32, when a large size sheet 550 is stacked, it is necessary to pass under the front end of the pressure arm 501. Therefore, in this embodiment, a guide roller 504 is provided to reduce the resistance during passage.

  Further, when stacking small size sheets 550, as shown in FIG. 31, when stacking large size sheets 550, the trailing edge of the sheet may float as shown in FIG. Therefore, a pressing arm 502 is provided integrally with the pressure arm 501 on the rear end side of the pressure arm 501 to suppress the lifting of the sheet on the rear end side of the pressure arm 501 and to provide a space above the uppermost stack portion. I try to secure it. As a result, the leading edge of the next discharged sheet is surely placed on the uppermost surface of the stacked sheets. The holding arm 502 shares the arm rotation fulcrum or has a rotation fulcrum in the vicinity thereof, and the sheet passing side is preferably formed in a concave shape, that is, in a letter-like shape when viewed from the front as illustrated. .

  In addition, the inclination angle of the bottom surface of the stacking tray 203 near the front end of the pressing arm 501 is made gentle so that small-size sheets are less likely to slip downstream. Thereby, a stable stacking state can be maintained even for a small-sized sheet.

  As described above, according to the present embodiment, the tension spring 503 that reduces the applied pressure according to the rotation amount of the pressure arm 501 is provided, and the applied pressure decreases as the sheet stacking height of the lower tray 203 decreases. Therefore, when discharging a large size sheet, the resistance when passing under the pressure arm 501 is low (low resistance) in a small number of thin thin sheets, and a thick sheet with strong waist When there are a large number of sheets, the applied pressure becomes high (high resistance), and the ideal loadability can be exhibited.

  Further, in the case of small size stacking, the guide roller 504 is positioned at the leading end of the sheet as shown in FIG. 31, and in the case of large size stacking, the arm 501 is positioned so that the guide roller 504 is positioned in the middle of the sheet as shown in FIG. The small sheet is stacked inside the arm 501, and the large sheet is stacked through the arm 501, so that the small sheet is collected on the upstream side of the lower tray 203. As a result, even in the case of a small size sheet, the stacking is not disturbed and a good stacking property can be exhibited.

  Further, as shown in FIG. 31, when stacking small-sized sheets, the leading edge of the sheet stacked by the leading edge sheet guide surface 501d on the leading edge of the letter “he” on the sheet passing side of the arm 501 is shifted in a platform shape. Since it can be loaded, it is less likely to collapse than stacking directly above even at the same loading height, and a large amount can be loaded.

  Further, since the guide roller 504 is provided at the tip of the pressure arm 501, resistance when passing under the pressure arm 501 can be reduced, and a large-sized sheet can be easily discharged. The sheet can be passed under the pressurizing arm 501 in order from the lower sheet stacked in the shape of a platform. As a result, regardless of whether the sheet is a large size or a small size, the sheets can be stacked satisfactorily.

  Further, as shown in FIG. 31 in the case of small size loading, as shown in FIG. 32 in the case of large size loading, as shown in FIG. 32, the sheet lift at the rear end portion should be suppressed and a space should be secured on the uppermost stacking portion. Therefore, it is possible to ensure that the leading edge of the next discharged sheet is always placed on the uppermost surface of the stack. This prevents the discharged sheets from colliding with the sheets on the stacking tray and disturbing the stacking.

Further, since the inclined angle in the vicinity where the inclined lower tray 203 and the guide roller 504 at the tip end of the pressure arm are in contact with each other is loosened, it is difficult because the lower discharge roller 83 pushes out the leading edge of the large sheet. When the leading edge of the small-sized sheet passes through, it is separated from the lower paper discharge roller 83, so that the speed of sliding down vigorously due to the inclination on the lower tray 203 can be reduced and stagnated upstream. This is makes it possible to improve the stackability.

1 is a diagram illustrating a system configuration of an image processing system including a sheet processing apparatus mainly showing a sheet post-processing apparatus according to an embodiment of the present invention and an image forming apparatus PR. FIG. It is the perspective view which expanded the principal part which shows the detail of the shift mechanism of the paper post-processing apparatus which concerns on embodiment of this invention. It is the perspective view which expanded the principal part of the shift tray raising / lowering mechanism of the paper post-processing apparatus which concerns on embodiment of this invention. FIG. 5 is a perspective view illustrating a structure of a paper discharge unit to a shift tray of the paper post-processing apparatus according to the embodiment of the present invention. FIG. 6 is a plan view of a staple processing tray of the paper post-processing apparatus according to the embodiment of the present invention as viewed from a direction perpendicular to the paper transport surface. It is a perspective view which shows the staple processing tray of the paper post-processing apparatus which concerns on embodiment of this invention, and its drive mechanism. FIG. 6 is a perspective view showing a sheet bundle discharge mechanism of the sheet post-processing apparatus according to the embodiment of the present invention. It is a perspective view which shows the end surface binding stapler of the paper post-processing apparatus which concerns on embodiment of this invention with a moving mechanism. It is a perspective view which shows the diagonal rotation mechanism of the end surface binding stapler in FIG. FIG. 6 is an operation explanatory view of a sheet bundle deflection mechanism of the sheet post-processing apparatus according to the embodiment of the present invention, and shows a state when a sheet or a sheet bundle is discharged to a shift tray. FIG. 11 is an operation explanatory view of the sheet bundle deflecting mechanism of the sheet post-processing apparatus according to the embodiment of the present invention, showing a state where the branch guide plate is rotated from the state of FIG. 10 to the discharge roller side. FIG. 12 is an operation explanatory diagram of the sheet bundle deflection mechanism of the sheet post-processing apparatus according to the embodiment of the present invention, in which the movable guide rotates from the state of FIG. 11 to the branch guide plate side and deflects the sheet bundle to the half-fold processing tray side. The state which formed the path | route is shown. FIG. 9 is an operation explanatory view of a folding plate moving mechanism of the sheet post-processing apparatus according to the embodiment of the present invention, and shows a state before entering a middle folding operation. FIG. 9 is an operation explanatory view of a folding plate moving mechanism of the sheet post-processing apparatus according to the embodiment of the present invention, and shows a state when returning to the initial position after the middle folding. It is a figure which shows the detail of the staple processing tray of the paper post-processing apparatus which concerns on embodiment of this invention, and a half-fold processing tray. 1 is a block diagram mainly showing a configuration of a control system of an image forming system according to an embodiment of the present invention, particularly a control configuration of a sheet post-processing apparatus. FIG. It is a flowchart which shows the process sequence of the non-stipple mode A in the paper post-processing apparatus which concerns on embodiment of this invention. It is a flowchart which shows the process sequence of the non-stipple mode B in the paper post-processing apparatus which concerns on embodiment of this invention. It is a flowchart which shows the processing procedure of the sort in the paper post-processing apparatus concerning embodiment of this invention, and a stack mode. 6 is a flowchart illustrating a processing procedure in a stipple mode in the sheet post-processing apparatus according to the embodiment of the present invention. It is a flowchart which shows the process sequence of the saddle stitch bookbinding mode in the paper post-processing apparatus which concerns on embodiment of this invention. FIG. 10 is an operation explanatory diagram illustrating a state of a sheet bundle stacked on a staple processing tray in the saddle stitch binding mode according to the embodiment of the present invention. It is operation | movement explanatory drawing which shows a state when it stacks | stacks with a staple processing tray in the saddle stitch bookbinding mode in embodiment of this invention, and is saddle-stitched. FIG. 10 is an operation explanatory diagram illustrating an initial state in which a sheet bundle that is saddle-stitched by a staple processing tray is deflected by a sheet bundle deflecting mechanism in the saddle stitch binding mode according to the embodiment of the present invention. FIG. 11 is an operation explanatory diagram illustrating a state when a sheet bundle that is saddle-stitched by a staple processing tray is deflected by a sheet bundle deflecting mechanism and sent to a half-fold processing tray in the saddle stitching binding mode according to the embodiment of the present invention. FIG. 10 is an operation explanatory diagram illustrating a state when a sheet bundle is positioned at a center folding position on the center folding processing tray in the saddle stitch binding mode according to the embodiment of the present invention. FIG. 9 is an operation explanatory diagram illustrating a state when a sheet folding operation is started by operating a folding plate in a folding processing tray in a saddle stitching binding mode according to an embodiment of the present invention. FIG. 9 is an operation explanatory diagram illustrating a state when a sheet bundle is folded in a middle folding roller by a middle folding roller and discharged in a saddle stitch bookbinding mode according to an embodiment of the present invention. FIG. 11 is an operation explanatory diagram illustrating a state in which the folding roller is separated when the sheet bundle is folded in the middle folding processing tray by the middle folding roller and discharged in the saddle stitch binding mode in the embodiment of the present invention. 1 is a diagram illustrating a sheet stacking apparatus according to an embodiment of the present invention. FIG. 10 is a diagram illustrating a stacking state of small-size sheet bundles that are saddle stitched in the sheet stacking apparatus according to the embodiment of the present invention. FIG. 10 is a diagram illustrating a stacking state of a large-size sheet bundle that is saddle stitched in the sheet stacking apparatus according to the embodiment of the present invention. FIG. 10 is a diagram illustrating a stacking state of a large-size sheet bundle that has been saddle stitched in a sheet stacking apparatus according to a conventional example. FIG. 10 is a diagram illustrating a stacking state of small-size sheet bundles that are saddle stitched in a sheet stacking apparatus according to a conventional example. FIG. 10 is a diagram illustrating a stacking state of a large-sized sheet bundle that is saddle stitched in a sheet stacking apparatus according to another conventional example. FIG. 10 is a diagram illustrating a stacking state of small-size sheet bundles that are saddle stitched in a sheet stacking apparatus according to another conventional example.

Explanation of symbols

83 Lower paper discharge roller 203 Lower tray 360 CPU
501 Pressure arm 501a Rotating fulcrum 501d Sheet tip guide surface 503 Tension spring 504 Guide roller PD Paper post-processing device PR Image forming device

Claims (6)

Discharging means for discharging the folded sheet;
A stacking tray for stacking the sheets;
An arm that has a rotation fulcrum on the upper side in the vicinity of the discharge means, is rotatably provided according to the height of the sheets stacked on the stacking tray, and presses the upper surface of the sheets on the stacking tray;
In a sheet stacking apparatus having
Means for changing the pressure of the arm according to the amount of rotation of the arm;
It means for changing the pre SL applied pressure, the sheet stacking, characterized in that to reduce the amount of rotation of the arm increases as the pressure increases, the load of the arm lower the sheet stacking height on the tray apparatus.   2. The sheet stacking according to claim 1, wherein a distance from a contact point of the arm tip portion to the stacking tray to the discharge unit is set to be shorter than a large sheet length and longer than a small sheet length. apparatus.   The shape on the paper passing side of the arm is characterized in that an inclination angle with respect to the stacking surface of the stacking tray on the side close to the stacking tray is set larger than an inclination angle on the separated side. The sheet stacking apparatus according to claim 2. The rear of the sheet provided integrally with the arm that shares the rotation fulcrum of the arm or has a rotation fulcrum in the vicinity of the rotation fulcrum and presses the raised rear end of the sheet discharged at the front end. The sheet stacking apparatus according to claim 1 , further comprising an end pressing member .   5. The sheet stacking apparatus according to claim 1, wherein the stacking tray is set to have a gentle inclination angle in the vicinity of the end of the arm being in contact with the stacking tray.   An image forming apparatus comprising the sheet stacking apparatus according to claim 1.

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