JP6296336B2 - Paper processing apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a sheet processing apparatus that performs processing on a sheet after image formation and the like, and an image forming apparatus such as a copying machine, a printer, and a facsimile equipped with the sheet processing apparatus.

  Conventionally, the image forming apparatus incorporates a paper processing apparatus that performs post-processing such as binding, punching, collating (sorting), bookbinding, folding, etc., on paper on which an image is formed by the image forming apparatus. Or an external one is known. In post-processing by such a sheet processing apparatus, it is necessary to stack a plurality of sheets in a state where they are aligned on a predetermined stacking tray at the time of binding processing or collating processing.

  Patent Document 1 describes a paper processing apparatus having a staple tray for stapling after a plurality of papers are stacked and aligned. In this sheet processing apparatus, sheets on which images are formed are introduced one by one from the introduction conveyance path. A conveyance roller is provided downstream of the introduction conveyance path, and the paper is positioned below the introduction conveyance path by the conveyance roller, and is installed with a gentle inclination so that the introduction conveyance path side is below the horizontal direction. It is conveyed so as to drop onto the staple tray. The staple tray includes a rear end reference fence for abutting and aligning the rear end of the paper, and a hitting roller, a jogger fence, a binding unit, and the like for aligning the conveyance direction with reference to the rear end reference fence. The paper transport direction is switched to the direction opposite to the transport direction by the transport roller by swinging while the roller hits the upper surface of the paper discharged onto the staple tray by the transport roller, and the rear end of the paper transport direction A vertical alignment is made by hitting against the rear end fence below the slope. Next, the jogger fence is abutted against the end portion in the width direction of the paper to perform horizontal alignment. When such operations are repeated and a predetermined number of sheets are stacked, the binding unit moves to a predetermined position at the trailing edge of the sheet and performs a binding process.

  Patent Document 2 includes an endless belt member having a sheet gripping unit such as a gripper for gripping the leading end of the sheet on the surface, and the belt member is attached to the surface while gripping the leading end of the sheet with the gripper on the lower surface side of the belt member. A paper processing device that conveys paper by moving is described. The paper transport path by the belt member of the paper processing apparatus has a front end stopper means for releasing the paper from the gripper by contacting the front end of the paper. With the belt member moved on the surface, the front end of the paper gripped by the gripper collides with the front end stopper means, whereby the paper is extracted from the gripper and dropped onto the lower stacking tray. As a result, the sheets are stacked on the stacking tray with the positions of the leading ends of the sheets aligned.

In the paper processing apparatus of Patent Document 1, the paper is discharged into a staple tray that is gently inclined in the lower horizontal direction by a conveying roller, and the upper surface of the paper is tapped and hit by a roller in a direction opposite to the direction in which the paper is discharged. Move and align with the rear edge reference fence, which is below the gentle slope. In this configuration, since the sheet moves in a free state until the sheet leaves the transport roller and is discharged into the staple tray, it is difficult to manage the time. For this reason, according to the behavior of the paper in a free state, it is necessary to allow the tapping roller to operate with an allowance, and there is a problem that productivity decreases. In addition, if the paper is in a free state, the posture of the paper during that time cannot be controlled, which may affect the alignment accuracy. Furthermore, the ultra-thin paper (25 g / m ² paper) has a problem that the paper is bent and cannot be aligned when it strikes the rear end reference fence.

  On the other hand, as in the paper processing apparatus of Patent Document 2, in the configuration in which the paper is gripped and moved by the paper gripping means and the paper is aligned by releasing the paper at a predetermined position, the paper is in a free state until the alignment position. There is no movement. For this reason, it is easy to manage the time required to align the sheets. In addition, the sheets can be aligned regardless of the paper type.

However, in the paper processing apparatus of Patent Document 2, the front end of the paper held by the gripper and conveyed by the surface movement of the belt member collides with the front end stopper means, and the paper is released by pulling out the paper from the gripper. Yes. In this configuration, there is a problem that the load on the leading edge of the paper is large, and the thin paper or ultrathin paper (25 g / m ² paper) is damaged at the leading edge of the paper.

  The present invention has been made in view of the above problems, and its purpose is to easily manage the time to the alignment position and align the sheets at a predetermined position on the stacking tray without damaging the sheets. A sheet processing apparatus and an image forming apparatus that can be stacked in a stacked state.

In order to achieve the above object, the invention of claim 1 includes a sheet conveying unit that conveys a sheet, a sheet holding unit that moves by grasping an end of the sheet conveyed by the sheet conveying unit, and a plurality of sheets. A stacking tray capable of stacking and stacking sheets, and a sheet processing apparatus that stacks the sheets on the stacking tray by releasing the sheets from the sheet gripping means on the stacking tray. The sheet detecting means for detecting that the rear end of the sheet in the transport direction has moved and a sheet pressing means for pressing the sheets on the stacking tray are provided to the sheet gripping means by the sheet detecting means. When it is detected that the rear end of the gripped paper in the transport direction has moved, the paper gripping means is stopped, the paper is pressed by the paper pressing means, and then the paper is gripped by the paper gripping means. The In which it characterized in that a control means for controlling so dividing.

  According to the present invention, it is easy to manage the time to the alignment position, and it is possible to stack the sheets in a state in which the sheets are aligned at a predetermined position on the stacking tray without damaging the sheets. is there.

1 is a schematic configuration diagram of an image forming apparatus according to an embodiment. 1 is a schematic configuration diagram of a sheet processing apparatus according to an embodiment. Explanatory drawing of pre-stack operation | movement of a paper processing apparatus. FIG. 6 is a schematic diagram for explaining the operation of the clamp unit according to the first embodiment. FIG. 6 is a schematic diagram for explaining the operation of the clamp unit according to the first embodiment. The schematic block diagram of a clamp unit. It is an expanded block diagram of a clamp, (a) shows when the clamp is closed, and (b) shows when the clamp is open. FIG. 10 is a schematic diagram for explaining the configuration and operation of a sheet pressing unit according to the second embodiment. FIG. 6 is a cross-sectional view illustrating an internal configuration of a pressing member of a sheet pressing unit according to a second embodiment. FIG. 4 is a schematic configuration diagram of a sheet pressing unit according to a third embodiment, where (a) is a perspective view and (b) is a top view. FIG. 10 is a schematic diagram for explaining the operation of a sheet pressing unit according to the third embodiment. FIG. 10 is a schematic diagram for explaining an operation of a sheet moving unit according to the fourth embodiment. FIG. 10 is a schematic diagram for explaining an operation of a sheet moving unit according to the fifth embodiment. FIG. 10 is a schematic configuration diagram of a sheet pressing unit according to a sixth embodiment, where (a) is a top view and (b) is a cross-sectional view. FIG. 10 is a schematic diagram for explaining the operation of a sheet pressing unit according to a sixth embodiment. FIG. 10 is a control flow diagram of a sheet pressing operation by a pressing roller of a sheet pressing unit according to a sixth embodiment. FIG. 10 is a schematic diagram for explaining the operation of a sheet pressing unit according to a seventh embodiment. FIG. 10 is a control flow diagram of a rotation operation of a pressing roller of a sheet pressing unit according to a seventh embodiment. FIG. 10 is an explanatory diagram of a pressing position for each paper size of a paper pressing unit according to an eighth embodiment, where (a) is a small size, (b) is a medium size, and (b) is a large size explanatory diagram. FIG. 10 is a control flow diagram of a movement operation of a pressing roller of a paper pressing unit according to an eighth embodiment according to a paper size.

Hereinafter, an example in which an embodiment of the present invention is applied to a sheet processing apparatus provided in a copying machine as an image forming apparatus will be described.
FIG. 1 illustrates an image forming apparatus including a sheet processing apparatus 200 according to the present embodiment and an image forming unit 100 such as a copying machine or a printer that supplies the sheet processing apparatus 200 with a sheet P as a sheet material after image formation. FIG.

  The image forming unit 100 according to the present embodiment includes an image processing circuit, a photoconductor, an optical writing device, a developing device, a transfer device, and a fixing device, although not particularly illustrated.

  The image processing circuit converts image data read by a scanner unit when the image forming unit 100 is a copying machine or image data input from an external device such as a personal computer into printable image data, and the converted image data Is output to the optical writing device.

  The optical writing device performs optical writing on the photoconductor based on the image signal output from the image processing circuit to form an electrostatic latent image on the surface of the photoconductor.

  The developing device develops toner on the electrostatic latent image formed on the surface of the photoreceptor by optical writing. The transfer device transfers the toner image on the surface of the photoreceptor visualized by the developing device onto the paper P. The fixing device fixes the toner image transferred onto the paper P onto the paper P.

  The sheet processing apparatus 200 is attached to the left side of the image forming unit 100 in the drawing, accepts the image-formed sheet P discharged from the image forming unit 100, and performs predetermined post-processing such as binding processing on the sheet P. It is applied to this.

  FIG. 2 is a schematic configuration diagram of the sheet processing apparatus according to the present embodiment. In the sheet processing apparatus 200, an introduction conveyance path 1 for receiving and conveying the sheet P from the image forming unit 100 is formed. In addition, three paths branched from the introduction conveyance path 1, that is, an upper conveyance path 2 toward the proof tray 6, a straight conveyance path 3 that performs shift processing and edge binding processing, and a lower conveyance path that performs saddle stitching and folding processing. 4 etc. are formed in the apparatus.

  In addition, the sheet processing apparatus 200 includes a control unit (not shown) that includes a CPU, a memory, and the like and performs operation control of various members in the sheet processing apparatus 200.

  An inlet sensor 13 is disposed in the introduction conveyance path 1, and the inlet sensor 13 detects that the paper P has been carried into the paper processing apparatus 200. An inlet roller pair 10 is provided downstream of the inlet sensor 13 in the paper transport direction, and a paper punching unit B that forms holes in the paper is disposed downstream of the inlet roller pair 10 in the paper transport direction.

  Further, a conveyance roller pair 11, a branch claw 7, and a branch claw 8 are provided on the downstream side of the introduction conveyance path 1 with respect to the paper punching unit B in the paper conveyance direction. The conveyance direction of the paper P conveyed by the conveyance roller pair 11 by rotating the branch claw 7 or the branch claw 8 is any one of the introduction conveyance path 1 to the upper conveyance path 2, the straight conveyance path 3, or the lower conveyance path 4. Switch to.

  The straight conveyance path 3 is provided with a conveyance roller pair 12 having a shift mechanism. In addition, a discharge roller 26, a driven roller 27, a discharge sensor 28, a discharge guide 32, and the like are provided at the most downstream portion (left end portion in FIG. 2) of the straight conveyance path 3, and the discharge is performed outside the apparatus. This is a discharge unit for discharging the paper P to the tray 5.

  The paper discharge roller 26 has a driven roller 27 that can come into contact with and separate from the paper discharge roller 26, and has a pair structure that can hold the paper in the straight conveyance path 3 and discharge it to the paper discharge tray 5. In this pair structure, the paper discharge guide 32 that supports the driven roller 27 is displaced so that a closed state in which the paper P can be pinched and discharged and an open state in which the paper P is not pinched can be selectively taken. It has become.

  In addition, a filler 40 is provided as a detection means for controlling the height of the paper discharge tray 5 above the paper discharge tray 5 near the discharge port. The filler 40 is rotatable so that the front end thereof is in contact with the upper surface of the paper stacked on the paper discharge tray 5 in the vicinity of the center position, and an upper surface detection that detects that the height position of the front end has reached a certain level near the root. A sensor (not shown) is provided. As a result, it is possible to detect that the paper surface height of the paper P stacked on the paper discharge tray 5 exceeds a certain level.

  When the sheet height rises due to an increase in the number of sheets stacked on the discharge tray 5 and the upper surface detection sensor (not shown) is turned on, a control unit (not shown) drives the discharge tray 5 up and down (not shown). ) To lower the discharge tray 5. When the discharge tray 5 is lowered and the upper surface detection sensor is turned off, the lowering of the discharge tray 5 is stopped. By keeping the distance from the paper discharge port to the paper stacking portion of the paper discharge tray 5 constant, the contact angle between the paper to be discharged and the paper discharge tray 5 is made constant. Thereby, the alignment quality of the sheets stacked on the paper discharge tray 5 can be stabilized. This operation is repeated, and when the paper discharge tray 5 reaches the specified tray full height, a stop signal is issued from the sheet processing apparatus 200 to the image forming unit 100 to stop the image forming operation of the system.

  The straight transport path 3 includes a staple tray 21 positioned below the transport roller pair 12 and a clamp unit 400 that grips the rear end of the paper P and transports it to a predetermined position on the staple tray 21. . The clamp unit 400 includes a clamp 401 as a paper gripping means, an endless clamp guide 402 that guides the movement path of the clamp 401, and a drive means (not shown) that moves the clamp. In addition, a paper sensor 25 is provided for detecting that the trailing edge of the paper held by the clamp has been conveyed to a predetermined position on the staple tray 21.

  The staple tray 21 is a sheet tray that stacks a plurality of conveyed sheets and stacks them as a sheet bundle to perform a binding process. On the staple tray 21, jogger fences 22, 23, a stapler 50, a rear end fence 24, and the like are arranged. The jogger fences 22, 23 advance and retreat in a direction perpendicular to the sheet surface, and align a plurality of sheets stacked on the staple tray 21 in the width direction. The stapler 50 is provided so as to be able to advance and retreat in a direction perpendicular to the paper surface, and is a binding unit that binds an appropriate position at the lower edge of the sheet bundle loaded on the staple tray 21. The rear end fence 24 is provided on the back side (stapler 50 side) of the staple tray 21 and restricts the sheet P from jumping out to the back side of the staple tray 21. A discharge claw 29 for discharging the bound sheet bundle is provided so as to be movable by the timing belt 30.

  In the lower conveyance path 4, conveyance roller pairs 61 and 62 and a saddle stitch stapler 51 are arranged. In the lower conveyance path 4, the sheet is conveyed to the saddle stitching position by the conveyance roller pair 61 and 62, the binding process is performed on the center of the sheet by the saddle stitching stapler 51, and the saddle-stitched sheet is conveyed downward by the conveyance roller pair 62 and 63. It is conveyed toward a stopper 64 provided at the lower end of the path 4. The paper transported in this way hits the stopper 64 and is temporarily stacked in the lower transport path 4. Then, the sheet folded in half by the sheet folding blade 71 or the sheet folding plate 72 of the sheet folding unit is discharged to the saddle stitching tray 9 by the discharge roller pair 73.

  The conveyance of the sheet to the lower conveyance path 4 passes through the introduction conveyance path 1, the leading edge of the sheet is detected by the leading edge detection sensor 14 (see FIG. 3), and the trailing edge of the sheet is transferred from the introduction conveyance path 1 to the lower conveyance path 4. The position of the branching claw 8 is switched after waiting for the time to pass through the branching part. Then, the transport roller pair 12 is rotated in the reverse direction to switch back the paper and transport the paper to the lower transport path 4.

  Here, in the paper processing apparatus 200, the next paper P cannot be received in the staple tray 21 while the edge binding stapling processing is being performed on the paper bundle stacked on the staple tray 21. For this reason, if the delivery of the paper P from the image forming unit 100 to the paper processing apparatus 200 is stopped so that a new paper P is not supplied to the staple tray 21 while the edge-binding stapling process is being performed, the productivity decreases. . Therefore, in the paper processing apparatus 200, the paper P is temporarily retained in the lower conveyance path 4 in order to increase the time required for the end binding staple processing while maintaining productivity. Thereafter, a plurality of sheets of paper P are simultaneously transported to the staple tray 21 to perform a so-called prestack process in which substantial time is gained.

  FIG. 3 is an explanatory diagram of the pre-stack operation, and the lower conveyance path 4 is also used as a pre-stack path during the end-stitching staple process. At the time of pre-stacking, the first sheet is transported by the transport roller pairs 11 and 12 (FIG. 3A). When the leading edge of the sheet is detected by the leading edge detection sensor 14 and the trailing edge of the sheet passes through the branching portion from the introduction conveying path 1 to the lower conveying path 4, the trailing edge of the sheet is conveyed to the position of the branching claw 8 (see FIG. 3 (b)), the position of the branch claw 8 is switched. When the position of the branch claw 8 is switched, the conveyance roller pair 12 rotates in the reverse direction, and the paper P is switched back from the straight conveyance path 3 to the lower conveyance path 4. The switched-back paper P is transported in the lower transport path 4 to a position where the front end of the paper passes through the transport roller pair 12 by the transport roller pair 61 (FIG. 3C).

  When the leading edge of the sheet comes out of the conveying roller pair 12 and the switchback is completed, the conveying roller pair 61 stops and the sheet P is prestacked in the lower conveying path 4. At the same time, the second sheet received from the image forming unit 100 to the introduction conveyance path 1 of the sheet processing apparatus 200 is conveyed by the conveyance roller pairs 11 and 12 (FIG. 3D).

  Then, when the leading edge of the second sheet is detected by the leading edge detection sensor 14 and conveyed by a certain amount, the conveying roller pair 61 is rotated in the reverse direction so that the first sheet prestacked in the lower conveying path 4 is fed to the straight conveying path 3. (3e). Then, the first sheet and the second sheet are overlapped and conveyed by the clamp unit 400 toward the staple tray 21 in the straight conveyance path 3 (FIG. 3F).

  The sheet processing apparatus 200 according to the present embodiment has a shift mode using the straight conveyance path 3, a staple mode, and a straight mode. The operation in the straight conveyance path 3 after the trailing edge of the sheet passes through the conveyance roller pair 11 is different in each of the shift mode, the staple mode, and the straight mode. Each mode will be described below.

<Shift mode>
The shift mode is a mode in which sheets are sorted by a predetermined number of right and left as viewed from the side of the image forming apparatus (see FIG. 2A) on the sheet discharge tray 5 without performing binding processing on the sheets. In the shift mode, the paper is transported by a transport roller pair 12 having a shift mechanism arranged in the straight transport path 3. The transport roller pair 12 is moved by a fixed amount in the direction perpendicular to the transport direction during transport by a driving unit (not shown), so that the paper is shifted by a constant amount on the straight transport path 3. Before the leading edge of the paper reaches the paper discharge roller 26 and the driven roller 27, the paper discharge guide 32 is in an open state. After the shift operation is completed, the paper discharge guide 32 is displaced to the closed state, the paper is nipped and discharged by the paper discharge roller 26 and the driven roller 27, and sequentially stacked on the paper discharge tray 5. By such an operation, when the paper is stacked on the paper discharge tray 5, the paper discharge positions are alternately shifted every predetermined number of sheets, and the paper is sorted.

  A sheet pressing member 31 for pressing the sheets stacked on the sheet discharge tray 5 is disposed at an attachment portion of the sheet discharge tray 5 to the main body of the sheet processing apparatus 200. The sheet pressing member 31 can selectively take a sheet pressing releasing operation and a sheet pressing operation by turning on / off a solenoid (not shown). That is, the solenoid is turned on in accordance with the conveyance of the paper to release the pressing operation of the paper pressing member 31, and when the paper passes the paper discharge roller 26 and the driven roller 27, the solenoid is turned off to press the paper.

<Staple mode>
The staple mode is a mode in which a predetermined number of sheets are bound by a stapler when a sheet is discharged and discharged. In the staple mode, the sheet conveyed to the straight conveyance path 3 is gripped by the clamp 401 before the sheet trailing edge passes through the conveying roller pair 12, and the sheet conveying means is moved from the conveying roller pair 12 to the clamping unit. 400 is passed. The clamp 401 grips the sheet and moves along the clamp guide 402 to push out the sheet and move it onto the lower staple tray 21. When the gripped rear end of the sheet moves to a predetermined position, the gripping by the clamp 401 is released and the sheets are stacked at a predetermined position on the staple tray 21. Thereby, the conveyance direction position (vertical direction position) is aligned on the staple tray 21.

  The sheets stacked at a predetermined position on the staple tray 21 are aligned in the width direction by the jogger fences 22 and 23. The jogger fences 22 and 23 are inserted into a guide shaft (not shown) fixed to the staple tray 21, are connected to a stepping motor via a timing belt, and are linearly reciprocated by forward and reverse rotation driving of the stepping motor. The jogger fences 22 and 23 can be driven independently. The staple tray 21 is provided with a home sensor (not shown) for detecting the standby position of the jogger fences 22 and 23.

  The aligned sheet bundle is stapled at the end of the sheet bundle by stapler 50 moving in a direction orthogonal to the sheet surface (paper width direction) and stapling at an appropriate position at the lower edge of the sheet bundle. The edge-bound paper is driven by a stepping motor (not shown) coupled to the timing belt 30 so that the discharge claw 29 is moved around to push out the rear end of the paper bundle, and the paper bundle is placed on the discharge tray 5. Paper is discharged.

  During discharge of a bundle of sheets, a solenoid (not shown) is turned on to release the sheet pressing member 31, and the discharge tray 5 is lowered by a certain amount. Further, the discharge guide 32 is raised at the timing when the trailing end of the sheet bundle passes the discharge sensor 28 to prepare for receiving the next sheet. At the same time, the solenoid is turned off and the sheet pressing member 31 presses the sheet.

<Straight mode>
In the straight mode, the sheet received from the image forming unit 100 is discharged to the discharge tray 5 without post-processing. In the straight mode, the clamp unit 400 is not used. The paper is transported by the transport roller pair 12 and the paper discharge roller 26 and is directly discharged to the paper discharge tray 5.

Next, the clamp unit 400 which is a characteristic part of the present embodiment will be described based on Example 1.
<Example 1>
4 and 5 are schematic diagrams for explaining the operation of the clamp unit 400 according to the first embodiment. When the sheet P is carried into the straight conveyance path 3, the clamp 401 stands by in an open state at a position that does not interfere with the conveyance path (FIG. 4A). When the leading edge of the sheet P passes through the conveying roller pair 12, the clamp 401 moves to the conveying surface along the clamp guide 402 and grips the trailing edge of the sheet (FIG. 4B). At this time, the conveying roller pair 12 releases the pressure and transfers the conveying means for the paper P from the conveying roller to the clamp 401. The clamp 401 that grips the trailing edge of the sheet moves along the clamp guide 402, and the sheet P gripped by the clamp 401 moves onto the staple tray 21 (FIG. 4C).

  When the trailing edge of the paper gripped by the clamp 401 (the leading edge in the conveyance direction by the clamp 401) is conveyed to the paper sensor 25 provided on the upper side of the staple tray 21 and detected by the paper sensor 25, the clamp 401 is stopped. (FIG. 5 (a)). With the clamp 401 stopped, the gripping by the clamp 401 is released (FIG. 5B). After releasing the grip, the clamp 401 moves along the clamp guide 402 and retracts from the staple tray 21. As a result, the paper P is stacked on the staple tray 21 (FIG. 5C). The clamp 401 moves along the clamp guide 402 and returns to the state shown in FIG.

  In the first embodiment, the paper sensor 25 is arranged such that the paper trailing edge detection position by the paper sensor 25 coincides with the paper alignment surface of the trailing edge fence 24 on the staple tray 21. As a result, the paper sensor 25 detects the trailing edge of the paper and releases the clamp 401, so that the paper P is stacked on the trailing edge fence 24. Note that the position where the paper P is gripped by the clamp 401 may be different, or the paper P gripped by the clamp 401 may be displaced within the clamp 401 during conveyance. Even in such a case, by detecting the trailing edge of the sheet by the sheet sensor 25 and releasing the clamp 401, the sheet P is always released at the same sheet-aligned surface position of the trailing edge fence 24. Can be stacked in the transport direction.

  FIG. 6 is a configuration diagram of the clamp unit 400. The clamp unit 400 includes two clamps 401a and 401b. The clamps 401 a and 401 b move along the endless clamp guide 402 to move up, down, left and right. The clamps 401a and 401b have guide members 403a and 403b. When the drive source (not shown) rotates, the link 405 rotates around the link rotation center 404, so that the guide members 403a and 403b move in the link 405. As a result, the clamps 401a and 401b move.

7A and 7B are enlarged configuration diagrams of the clamp, in which FIG. 7A shows a state when the clamp is closed (when the paper is gripped), and FIG. 7B shows a state when the clamp is opened (when the grip is released). Since the clamps 401a and 401b have the same configuration, the description will be made with the suffix omitted.
The clamp 401 is mainly composed of a base 501, a butting part 502, and an opening / closing part 503. When the opening / closing part 503 is closed, a pressure capable of gripping the paper is applied by the torsion spring 504. When opening the opening / closing part 503, the opening / closing part 503 is rotated about the rotation center 506 by pushing the rear end of the opening / closing part 503 with a solenoid 505 provided in the base 501.

<Example 2>
In the second embodiment, the clamp unit 400 according to the first embodiment includes a sheet pressing unit 700 that presses sheets stacked on the staple tray 21 from above.

  FIG. 8 is a schematic diagram for explaining the configuration and operation of the sheet pressing unit 700 according to the second embodiment. The sheet pressing means 700 includes a pressing member 701 that slides inside a fixed cylindrical case member 700a, a compression spring 702 that biases the pressing member 701 toward the sheet, a cam 703 that is coupled to the compression spring 702, and the like. have. FIG. 8A shows the home position of the pressing member 701 in which the pressing member 701 is lifted upward. FIGS. 8B to 8D show a pressing state in which a sheet is pressed by a pressing member 701 by rotating a cam 703 by a home position sensor, a rotating pulley, and a rotating motor (not shown) outside a side plate (not shown). Yes. As shown in FIG. 9, the pressing member 701 is divided into an upper case 701a and a lower case 701b, and a compression spring 701c is provided therein, and the compression spring 701c can be expanded and contracted according to the thickness of the sheet bundle at the time of pressing. It is the composition.

The operation of the sheet pressing means 700 will be described. When the trailing edge of the paper gripped by the clamp 401 (the leading edge as the conveyance direction by the clamp 401) is detected by the paper sensor 705 provided on the upstream side of the paper pressing means 700, the pressing member 701 stands by at the home position (FIG. 8 (a)). When the paper sensor 25 detects the trailing edge of the paper gripped by the clamp 401 and the clamp 401 stops, the pressing member 701 is pressed (FIG. 8B). When the clamp 401 is released after a certain time, the sheet is released at the alignment position (FIG. 8C). The clamp 401 is retracted from the paper alignment position (FIG. 8D). When the pressing member 701 is brought into the pressed state by the operations of FIGS. 8B to 8D, the sheet bundle can be maintained in the aligned state, and the alignment accuracy can be improved.
Although the trailing edge fence 24 is not provided in FIG. 8, the trailing edge of the sheet is detected by the sheet sensor 25 provided at a position to be aligned, the clamp 401 is stopped, and the sheet is kept pressed to keep the clamp 401. Since the grip is released, the paper is accurately released according to the position of the paper. For this reason, good matching is performed.

<Example 3>
The third embodiment is different from the clamp unit 400 of the second embodiment in the configuration of the sheet pressing means. The sheet pressing unit according to the third embodiment uses a flexible rotating member 800 such as a paddle as a pressing member. 10A and 10B show a schematic configuration of a flexible rotating member 800 as a sheet pressing unit according to the third embodiment. FIG. 10A is a perspective view and FIG. 10B is a top view. The flexible rotating member 800 has a rubber plate 802 that is an elastic body on the peripheral surface of a holder 801 attached to a shaft 803. When the shaft 803 is rotated by the drive source 806 via the pulley 804 and the belt 805, the rubber plate 802 is rotated to contact and hold the rear end of the sheet. As a result, the sheet is held in the staple tray 21. Since the rubber plate 802 is an elastic body, it can cope with the thickness of the sheet bundle at the time of alignment. Further, the holder 801 has a detection plate 807, and the position of the flexible rotating member 800 is detected by the sensor 808.

  FIG. 11 is an explanatory diagram of the operation of the flexible rotating member 800 which is a sheet pressing unit according to the third embodiment. Before the paper P is carried into the staple tray 21, the rubber plate 802 stands by at a position where it can be retracted from the paper bundle (FIG. 11A). When the paper sensor 25 detects the trailing edge of the paper gripped by the clamp 401 and the clamp 401 stops, the shaft 803 rotates and the paper P is pressed by the rubber plate 802. Thereafter, the clamp 401 releases the grip and releases the paper P (FIG. 8B). In the third embodiment, the trailing edge fence 24 is provided at the end of the staple tray 21, and the sheet sensor 25 is disposed so that the sheet detection position of the sheet sensor 25 coincides with the sheet alignment surface of the trailing edge fence 24. The rear end fence 24 restricts the sheet P from protruding from the staple tray 21 at this position. The clamp 401 that has released the sheet retreats from the sheet alignment position. At this time, since the rubber plate 802 is pressing the paper, the paper bundle P ′ can maintain the aligned state (FIG. 11C).

<Example 4>
The fourth embodiment has a configuration including the flexible rotating member 800 and the rear end fence 24 similar to those of the third embodiment. In the fourth embodiment, when the trailing edge of the sheet is detected by the sheet sensor 25, the grip 401 is released without stopping the clamp 401 and the productivity is improved. However, when the clamp 401 is released while the clamp 401 is moved and the paper P is stacked on the staple tray 21, the paper P is shifted in the clamp moving direction from the position released by the inertial force. For this reason, the paper sensor 25 is arranged so that the rear end of the paper is detected at a position separated from the predetermined distance by predicting the amount of deviation. However, this method increases the variation in the loading position as compared with the configuration in which the clamp 401 is stopped and released. In order to correct the variation and align it at the sheet alignment position, a flexible rotating member 800 is used as a mechanism for transporting the sheet rear end to the sheet alignment surface of the rear end fence 24 that is the sheet alignment position.

  FIG. 12 is a schematic diagram for explaining the operation of the flexible rotating member 800 as the sheet moving unit according to the fourth embodiment. As described above, the sheet sensor 25 is arranged at a certain distance from the sheet alignment surface of the rear end fence 24 serving as the sheet alignment position in consideration of the shift amount of the sheet due to the inertial force. The sheet sensor 25 detects the trailing edge of the sheet P held by the clamp 401 and conveyed to the staple tray 21 (FIG. 12A). When the paper sensor 25 detects the rear edge of the paper, the clamp 401 releases the paper and releases the paper, retracts from the staple tray 21 without stopping the movement, and simultaneously rotates the flexible rotating member 800 (see FIG. 12 (b)). By rotating the flexible rotating member 800, the rear end of the released paper P is carried to the rear end fence 24 (FIG. 12C). In addition, as shown in FIG. 12, you may provide the rubber plate 802 of a flexible rotation member in multiple places.

<Example 5>
In the fifth embodiment, the productivity is improved by releasing the grip while the clamp 401 is moved without being stopped as in the fourth embodiment. In the fifth embodiment, in order to correct the variation in the stacking position and align it to the paper alignment position, the paper leading end pushing means 900 that pushes the paper leading edge opposite to the paper trailing edge gripped by the clamp 401 is used as the paper moving means. Yes.

  FIG. 13 is a schematic diagram for explaining the configuration and operation of the paper leading edge pressing unit 900 according to the fifth embodiment. The paper leading edge pressing means 900 includes a pressing member 901, a timing belt 902, a pulley 903, and the like. The timing belt 902 is wound around a pulley 903, and the push member 901 is attached to the belt on a surface so as to be perpendicular to the timing belt 902. The pulley 903 can be rotated by a motor (not shown). The staple tray 21 has a groove or a hole so as not to interfere with the pressing member 901. The push member 901 is configured to be slidable on the staple tray 21 while keeping the vertical direction as the timing belt 902 rotates. In FIG. 13, the timing belt 902 and the pulley 903 are provided above the staple tray 21. However, the timing belt 902 and the pulley 903 may be disposed below the staple tray 21 and the pushing member 901 may protrude from the lower side. Further, the driving means is not limited to the configuration using the timing belt 902 and the pulley 903, and may be a configuration using a rack and a pinion.

  The trailing edge of the sheet P held by the clamp 401 and conveyed to the staple tray 21 is arranged at a certain distance from the sheet alignment surface of the trailing edge fence 24 and is detected by the sheet sensor 25 (FIG. 13A). . When the paper sensor 25 detects the trailing edge of the paper, the clamp 401 releases the paper, releases the paper, and retracts from the staple tray 21 without stopping the movement. The pushing member 901 is moved so as to follow the clamp 401, and the leading edge of the sheet is pushed (FIG. 13B). By being pressed by the pressing member 901, the rear end of the sheet P is aligned with the rear end fence 24 (FIG. 13C). The amount of movement of the pressing member 901 at this time is determined by the size of the paper. For this reason, when the paper is pushed and aligned by the movement of the push member 901, the paper P is not pushed in from the paper alignment surface of the rear end fence 24, and the paper is not damaged.

  Next, the pushing member 901 is moved in the reverse direction, and the pushing member 901 is retracted from the leading end side of the sheet bundle (FIG. 13D). Thereby, a collision with the conveyed paper held by the clamp 401 is avoided. The amount of movement that the push member 901 retracts varies depending on the size of the paper (FIG. 13E). After all sheets are aligned, stapling is performed. When the sheet bundle is discharged, the push member 901 is retracted to a position where the sheet bundle outlet is opened (FIG. 13F).

<Example 6>
The sixth embodiment is different from the clamp unit 400 of the second embodiment in terms of the configuration of the sheet pressing unit. The sheet pressing means according to the sixth embodiment includes a roller rotating mechanism 850 having a pressing roller 851 that is rotatable as a pressing member. Then, with the front end of the paper P being held by the clamp 401, a press roller 851 that is freely rotatable from the upper surface of the paper P is applied, the paper P is stretched and conveyed while eliminating the bending, and the paper P is abutted against the rear edge fence 24. The entire structure is stacked.

FIG. 14 is a schematic configuration diagram of a sheet pressing unit according to the sixth embodiment, where (a) is a top view and (b) is a cross-sectional view. FIG. 15 is a schematic diagram for explaining the operation of the sheet pressing unit according to the sixth embodiment.
As shown in FIGS. 14A and 14B, a roller rotation mechanism 850 that is a sheet pressing unit of the sixth embodiment includes a pressing roller 851 that can be moved up and down. Then, the pressing roller 851 can be contacted and separated in the vicinity of the leading end of the sheet P conveyed and aligned by the clamp 401 on the staple tray 21 that functions as the sheet bundle P ′ or the temporary stacking tray at the rear end fence 24. It is configured.

  Specifically, the two pressing rollers 851 are rotatably supported by a roller rotation shaft 852 that is orthogonal to the conveyance direction of the paper P that is conveyed while being held by the clamp 401. A roller rotating arm 853 that holds the center in the length direction of the roller rotation shaft 852 on one end side is transported in a state where the second pressing roller 851 is held by the clamp 401 with the other end side as a fulcrum. It rotates so as to be pressed against P or separated from the paper P. When the roller turning arm 853 is turned by turning on / off a solenoid (not shown), the rotatable pressing roller 851 held on one end side moves up and down.

  As shown in FIG. 15A, when the paper P gripped by the clamp 401 is transported toward the rear end fence 24 (when transport is started), the pressing roller 851 is moved upward. It is in a retracted (separated) state. Then, as shown in FIG. 15B, it is detected by a sensor (not shown) that the clamp 401 has passed the pressing roller 851, and the rotation-free pressing roller 851 is rotated by the roller rotating mechanism 850 to carry it. The load is applied to the upper surface of the sheet P being applied. Thereafter, as shown in FIG. 15C, a force in the direction opposite to the conveyance direction is applied to the paper P being conveyed by the clamp 401 by applying a load with the pressing roller 851, and the paper P is stretched to extend the paper P. The paper P is in a state of being conveyed while eliminating the bending. Thereafter, the paper P is conveyed while maintaining the state shown in FIG. 15C, and the rear end of the paper P gripped by the clamp 401 reaches the rear end fence 24 as shown in FIG. 15D. become.

When the paper sensor 25 detects that the rear edge of the paper P has reached the rear edge fence 24, as shown in FIG. 15 (e), the clamp 401 releases the paper and releases the paper. Retreat from the staple tray 21 without stopping. At the same time, the pressing roller 851 is retracted (separated) from the paper P. Thereafter, as shown in FIG. 15 (f), the sheets P fall on the sheet bundle P ′ along the rear end fence 24 and are stacked.
In the paper pressing means of the sixth embodiment, as described above, a force in the reverse direction of the conveyance direction by the pressing roller 851 acts while being conveyed while the rear end of the paper P is held by the clamp 401. The sheet P is conveyed while eliminating the bending. Further, the sheet P is abutted against the rear end fence 24 while receiving a force in a direction in which the sheet P is stretched with respect to the transport direction. For this reason, the rear end of the paper P is aligned, and at the same time, the entire paper P is aligned. At that moment, the clamp 401 releases the paper P and retreats so that the paper P is moved along the rear edge fence 24. The sheet P can be dropped onto the sheet bundle P ′ and loaded with high accuracy.

The operation control by the control unit of the sheet pressing means (roller rotation mechanism 850) will be described in more detail with reference to the control flowchart of FIG.
As shown in the control flow diagram of FIG. 16, the paper P is gripped by the clamp 401 of the clamp unit 400, and conveyed toward the rear edge fence 24 (S101). Thereafter, it is determined whether or not the clamp 401 has passed the pressing roller 851 (S102).

When the clamp 401 does not pass the pressing roller 851 (No in S102), this determination is repeated until the clamp 401 passes the pressing roller 851.
On the other hand, when the clamp 401 passes through the pressing roller 851 (Yes in S102), the roller rotating mechanism 850 is operated to lower the freely rotating pressing roller 851 and hit the upper surface of the paper P (S103). In this way, the pressing roller 851 is lowered and applied to the upper surface of the paper P being transported by the clamp 401, thereby applying a force in the direction opposite to the paper transport direction to the paper P and eliminating the bending of the paper P. The paper P can be conveyed.

Thereafter, it is determined whether the trailing edge of the paper P has reached the trailing edge fence 24 (S104).
If the trailing edge of the paper P has not reached the trailing edge fence 24 (No in S104), this determination is repeated until the trailing edge of the paper P reaches the trailing edge fence 24.
On the other hand, when the trailing edge of the paper P reaches the trailing edge fence 24 (Yes in S104), the gripping of the paper P by the clamp 401 is released, and the roller rotating mechanism 850 is operated to hold the pressing roller 851. (S105). As described above, by releasing the grip of the clamp 401 and retracting the pressing roller 851, the paper P can be dropped along the rear end fence 24 and stacked on the paper bundle P ′.

  As described above, in the sixth embodiment, the roller rotating mechanism 850 that presses the paper P conveyed on the staple tray 21 is provided, and the roller rotating mechanism 850 includes the pressing roller 851 that can be moved up and down. Yes. Then, the pressing roller 851 is lowered and pressed against the paper P held by the clamp 401. With this configuration, the deflection of the paper P can be eliminated, and in this state, the paper P can be dropped onto the paper bundle P ′ or the stacking tray along the trailing edge fence 24 to accurately stack the paper P.

In the sixth embodiment described above, the configuration in which the pressing roller 851 is raised and separated from the paper P simultaneously with the release of the grip of the paper P by the clamp 401 has been described. However, the present invention is limited to such a configuration. It is not something. Prior to releasing the gripping of the paper P by the clamp 401, the pressing roller 851 may be raised and separated from the paper P.
As described above, the following effects can be obtained by releasing the gripping of the paper P by the clamp 401 or by releasing the gripping and lifting the pressing roller 851 away from the paper P. The paper P can be dropped on the paper bundle P ′ or the staple tray 21 along the rear end fence 24 so that the paper P can be stacked with high accuracy.

<Example 7>
The seventh embodiment is different from the clamp unit 400 of the sixth embodiment in terms of the configuration and operation control of the roller rotation mechanism 850 that is a sheet pressing unit. In the roller rotating mechanism 850 of the seventh embodiment, the rear end of the sheet is abutted against the rear end fence 24, and then the press roller 851 rotated in the reverse direction with respect to the sheet transport direction is applied to the vicinity of the front end of the sheet to stretch the sheet P. It is configured to load after eliminating the deflection.
FIG. 17 is a schematic diagram for explaining the operation of the sheet pressing unit according to the seventh embodiment. FIG. 18 is a control flowchart of the rotation operation of the pressing roller 851 of the roller rotating mechanism 850 which is a sheet pressing unit according to the seventh embodiment.

The roller rotation mechanism 850 of the seventh embodiment includes a configuration in which the pressing roller 851 is rotated in the reverse direction with respect to the conveyance direction of the paper P in addition to the above-described sixth embodiment.
The configuration and operation of the roller rotation mechanism 850 according to the seventh embodiment will be described with reference to FIG. As shown in FIG. 17A, when the paper P gripped by the clamp 401 is conveyed toward the rear end fence 24, the presser roller 851 is still stopped and in a retracted state. Thereafter, as shown in FIG. 17B, when a sensor (not shown) detects that the clamp 401 has passed the presser roller 851 and has reached the sheet bundle P ′ (staple tray 21), the presser roller 851 Then, reverse rotation with respect to the transport direction of the paper P is started. At this time, the roller rotation arm 853 is not rotated, and the presser roller 851 is idle at the retracted position.

Then, as shown in FIG. 17C, when the paper sensor 25 detects that the rear end of the paper P conveyed by the clamp 401 has reached the rear end fence 24, the roller rotating arm 853 is rotated, The presser roller 851 is lowered and applied to the upper surface of the paper P. At this time, the clamp 401 stops while holding the paper P.
Then, as shown in FIG. 17D, the press roller 851 that is rotating in the reverse direction with respect to the transport direction is applied to the upper surface of the paper P, so that the bending of the paper P is eliminated and the paper P is fully extended. The clamp 401 stops while holding the paper P.
After that, as shown in FIG. 17E, the clamp 401 releases the grip of the paper P and retreats, and at the same time, the presser roller 851 is also retracted from the paper P, and as shown in FIG. The paper P is dropped and stacked on the paper bundle P ′ along the end fence 24. At this time, the clamp 401 is further retracted, and the presser roller 851 stops after retracting.

The operation control by the control unit of the sheet pressing means (roller rotation mechanism 850) will be described in more detail with reference to the control flowchart of FIG.
As shown in the control flow diagram of FIG. 18, the sheet P is gripped by the clamp 401 of the clamp unit 400 and conveyed toward the rear end fence 24 (S <b> 201). Thereafter, it is determined whether or not the clamp 401 has passed the pressing roller 851 (S202).

If the clamp 401 does not pass the pressing roller 851 (No in S202), this determination is repeated until the clamp 401 passes the pressing roller 851.
On the other hand, when the clamp 401 passes through the pressing roller 851 (Yes in S202), a driving source (not shown) of the roller rotating mechanism 850 is driven to drive the pressing roller 851 in a direction opposite to the sheet conveyance direction of the sheet P. The rotation is started (S203).
Thereafter, it is determined whether the trailing edge of the paper P has reached the trailing edge fence 24 (S204).
If the trailing edge of the paper P has not reached the trailing edge fence 24 (No in S204), this determination is repeated until the trailing edge of the paper P reaches the trailing edge fence 24.
On the other hand, when the rear end of the paper P reaches the rear end fence 24 (Yes in S204), the roller rotating arm 853 of the roller rotating mechanism 850 is rotated to rotate backward with respect to the transport direction. The holding roller 851 is lowered and applied to the upper surface of the paper P (S205).

As described above, the pressing roller 851 rotated in the reverse direction with respect to the conveyance direction of the paper P is lowered, and the pressing roller 851 is pressed on the upper surface of the paper P held by the clamp 401 for a preset time for each paper size. Hit roller 851. Specifically, it is determined whether or not a preset time has elapsed for each paper size (S206). If the preset time has not elapsed (No in S206), the preset time has elapsed. Repeat this judgment until
Then, when a preset time has elapsed (Yes in S206), the holding of the paper P by the clamp 401 is released and the paper P is retracted. At the same time, the presser roller 851 is retracted and the paper P is dropped along the rear end fence 24. Then, they are stacked on the sheet bundle P ′ (S207).
Thereafter, when the presser roller 851 is retracted, its rotation is stopped (S208).

  As described above, in the seventh embodiment, the pressing roller 851 is held on the paper P held by the clamp 401 while the pressing roller 851 is rotated in the direction opposite to the conveyance direction of the conveyed paper P. Lower. With this configuration, the bending of the paper P is eliminated by stretching the paper P, and in that state, the paper P is dropped onto the paper bundle P ′ or the stacking tray along the trailing edge fence 24 to accurately stack the paper P. Can do.

  Further, the position where the pressing roller 851 is lowered is the position on the leading end side of the sheets P stacked on the staple tray 21, that is, the sheet bundle P '. With this configuration, the end of the sheet P opposite to the side gripped by the clamp 401 can be regulated by the press roller 851, the leading end of the sheet P is pulled back in the direction opposite to the transport direction, and the sheet P is pulled. Can be stretched. Accordingly, the deflection of the paper P can be eliminated, and the paper P can be dropped on the paper bundle P ′ and the staple tray 21 along the trailing edge fence 24 in that state, and the paper P can be stacked with high accuracy.

<Example 8>
The eighth embodiment is different from the clamp units 400 of the sixth and seventh embodiments in terms of the configuration and operation control of the roller rotation mechanism 850 that is a sheet pressing unit. The roller rotation mechanism 850 according to the eighth embodiment is configured to obtain the paper size information of the paper P output from the image forming apparatus and move the presser roller 851 to a preset position for each paper size.

  FIG. 19 is an explanatory diagram of the pressing position for each paper size of the roller rotation mechanism 850 that is a paper pressing unit according to the eighth embodiment, where (a) is a small size, (b) is a medium size, and (c) is a size. It is explanatory drawing of a large size. FIG. 20 is a control flowchart of the movement operation of the pressing roller 851 of the roller rotation mechanism 850 serving as the sheet pressing unit according to the eighth embodiment according to the sheet size. In each of FIGS. 19A, 19B, and 19C, the upper diagram shows a top view and the lower diagram shows a side view.

The roller rotation mechanism 850 of the seventh embodiment includes a configuration for moving the presser roller 851 to a position set in advance for each paper size in addition to those of the sixth and seventh embodiments. A configuration and operation for moving the presser roller 851 to a preset position for each paper size by the roller rotation mechanism 850 of the eighth embodiment will be described with reference to FIG.
FIG. 19 shows a state where the presser roller 851 is moved to a position corresponding to the small size in (a), the medium size in (b), and the large size in (c) as an example of the paper size.

As shown in FIGS. 19A, 19B, and 19C, in the roller rotating mechanism 850 of the eighth embodiment, the pressing roller 851, the roller rotating shaft 852, the roller rotating arm 853, and the like are attached to the carriage guide 856. A carriage 855 that is movable in the conveyance direction of the paper P along the direction is held. The carriage 855 is connected to a carriage belt 857 consisting of a timing belt spanned between two stretching rollers. A carriage belt driving source 858, which is a driving source for rotationally driving the stretching roller on one end side, is connected. Move by driving.
As described above, the carriage 855 has a mechanism for holding the pressing roller 851, and the position of the pressing roller 851 is determined by the movement of the carriage 855.

Control by the control unit of the moving mechanism including the carriage 855, the carriage guide 856, the carriage belt 857, the carriage belt drive source 858, and the like that moves the pressing roller 851 and the like is performed as follows.
As shown in the control flow diagram of FIG. 20, first, the paper size information of the paper output from the image forming apparatus is obtained (S301). Thereafter, the paper size is confirmed. That is, it is determined whether or not the paper size has been confirmed (S302).

If the paper size cannot be confirmed (No in S302), this determination is repeated until the paper size can be confirmed.
On the other hand, when the paper size can be confirmed (Yes in S302), the carriage belt drive source 858 of the roller rotation mechanism 850 is operated to move the carriage 855 to a preset position for each paper size (S303). ).
Thereafter, it is confirmed whether the carriage 855 has moved to the correct position (S304). If the carriage 855 is not moved to the correct position in this confirmation (No in S304), the carriage 855 returns to the correct position (S303) and is repeated until the carriage 855 moves to the correct position.
On the other hand, when the carriage 855 has been moved to the correct position (Yes in S304), the control of the moving mechanism is terminated.

  As described above, in the eighth embodiment, the pressing roller 851 is movable in the conveyance direction of the paper P conveyed on the staple tray 21 and moves the pressing roller 851 based on the paper size information of the paper P. . Then, the pressing roller 851 is lowered onto the paper P held by the clamp 401. With this configuration, the presser roller 851 can be arranged (moved) at an optimal position for each paper size, the deflection of the paper P can be eliminated, and the paper P can be stacked with high accuracy.

As described above, in the present embodiment, the configuration and operation of the clamp unit 400 have been described using the conveyance to the staple tray 21 that performs the staple processing, but the present invention is not limited thereto. The present invention can be applied to conveyance to a sheet stacking tray in which a plurality of sheets are aligned and stacked. In this embodiment, the image forming apparatus applied to the paper processing apparatus 200 attached to the copying machine that is the image forming unit 100 has been described. However, a configuration in which the paper processing apparatus is incorporated may be used.
In addition, by incorporating the sheet processing apparatus 200 of each of the embodiments described above, it is possible to provide an image forming apparatus that can perform sheet alignment with an inexpensive configuration.

What has been described above is merely an example, and the present invention has a specific effect for each of the following modes.
(Aspect A)
A paper transporting means for transporting the paper P, a paper gripping means such as a clamp 401 that grips and moves the end of the paper transported by the paper transporting means, a staple tray 21 that can stack a plurality of papers, and the like A sheet processing apparatus that stacks sheets on the stacking tray by releasing the sheet gripping by the sheet gripping means on the stacking tray. This paper processing apparatus includes paper detection means such as a paper sensor 25 for detecting that the edge of the paper has moved to a predetermined position on the stacking tray, and the edge of the paper has been moved by the paper detection means. When detecting this, a control means is provided for controlling the paper gripping means to release the gripping of the paper.

  According to (Aspect A), by detecting that the paper edge has moved to a predetermined position on the stacking tray by the paper detection means, and releasing the grip of the paper by the paper gripping means, The paper can be released from the paper gripping means and aligned on the stacking tray while being aligned at a predetermined position. This configuration is different from the configuration in which, as in Patent Document 2, in order to release the paper from the paper gripping means at a predetermined position, the paper front end collides with the front end stopper means and the paper is pulled out from the paper gripping means. The load on the edge is small, and the occurrence of damage in thin paper or ultrathin paper can be suppressed. Compared with Patent Document 1, since the paper is not freed up to the alignment position, the time until the alignment position can be managed, and the alignment can be performed regardless of the paper type. it can.

(Aspect B)
In (Aspect A), an abutting member such as a rear end fence 24 against which the leading end of the sheet in the moving direction of the stacking tray by the sheet gripping unit abuts is provided. According to this, as described in the above embodiment, the paper P can be prevented from jumping out in the moving direction, and accurate alignment can be performed.

(Aspect C)
In (Aspect A) or (Aspect B), when the control unit detects that the end of the paper gripped by the paper gripping unit has moved by the paper detection unit, the control unit stops the paper gripping unit and uses the paper gripping unit. The grip of the paper is released. According to this, as described in the first embodiment, accurate sheet alignment can be performed.

(Aspect D)
In (Aspect C), the sheet holding means 700 for pressing the sheets on the stacking tray is provided, and the control means grips the paper when the paper detection means detects that the end of the paper gripped by the paper gripping means has moved. After the means is stopped and the paper is pressed by the paper pressing means, the paper gripping by the paper gripping means is released. According to this, as described in the second embodiment, accurate sheet alignment can be performed.

(Aspect E)
In (Aspect D), the sheet pressing means is a flexible rotating member 800. According to this, as described in the third embodiment, accurate sheet alignment can be performed.

(Aspect F)
In (Aspect B), a paper moving means for moving the paper toward the abutting member such as the rear end fence 24 is provided, and the control means is gripped by the paper gripping means such as the clamp 401 by the paper detection means such as the paper sensor 25. When it is detected that the edge of the paper has moved, the paper gripping means is released while the paper gripping means is moved, and the paper released from the paper gripping means is abutted by the paper moving means. Move towards. According to this, as described in the fourth and fifth embodiments, the alignment accuracy can be maintained while improving the productivity.

(Aspect G)
In (Aspect F), the sheet moving means is a flexible rotating member 800. According to this, as described in the fourth embodiment, good alignment accuracy can be obtained.

(Aspect H)
In (Aspect F), the sheet moving unit is a sheet leading end pushing unit 900 that pushes the end opposite to the sheet trailing end held by the sheet holding unit. According to this, as described in the fifth embodiment, good alignment accuracy can be obtained. Further, the paper P is not pushed in from the paper alignment surface of the rear end fence 24, and the paper P is not damaged.

(Aspect I)
In (Aspect A) or (Aspect B), a sheet pressing unit such as a roller rotation mechanism 850 that presses the sheet conveyed on the stacking tray is provided, and the sheet pressing unit includes a pressing roller 851 that can be moved up and down. A press roller is provided, and the press roller is lowered and pressed against the paper held by the paper holding means. According to this, the bending of the paper P is eliminated, and the paper P can be accurately stacked by dropping the paper P onto the paper bundle P ′ or the stacking tray along the abutting member such as the rear end fence 24 in this state. it can.

(Aspect J)
In (Aspect I), the pressing roller is lowered onto the paper gripped by the paper gripping means while the pressing roller is rotated in the direction opposite to the transport direction of the transported paper. According to this, the deflection is eliminated by stretching the paper P, and in that state, the paper P is dropped onto the paper bundle P ′ or the stacking tray along the abutting member such as the rear end fence 24 and the paper P is accurately loaded. Can be made.

(Aspect K)
In (Aspect I) or (Aspect J), before releasing the gripping of the paper by the paper gripping means or releasing the gripping, the presser roller is raised and separated from the paper. According to this, it is possible to load the paper P with high accuracy by dropping the paper P onto the paper bundle P ′ or the stacking tray along the abutting member.

(Aspect L)
In any one of (Aspect I) to (Aspect K), the position where the pressing roller is lowered is the position on the leading end side of the paper loaded on the stacking tray. According to this, the end portion of the paper P opposite to the side gripped by the paper gripping means can be regulated by the presser roller, the front end side of the paper can be pulled back in the direction opposite to the transport direction, and the paper P can be stretched. Therefore, the deflection of the paper P can be eliminated, and in this state, the paper P can be dropped onto the paper bundle P ′ or the stacking tray along the abutting member such as the rear end fence 24 and the paper P can be stacked with high accuracy.

(Aspect M)
In any one of (Aspect I) to (Aspect L), the pressing roller is movable in the conveyance direction of the paper conveyed on the stacking tray, and the pressing roller is moved based on the paper size information of the paper, The pressing roller is lowered onto the paper held by the paper holding means. According to this, the presser roller can be arranged at an optimum position for each paper size, the bending of the paper P can be eliminated, and the paper P can be stacked with high accuracy.

(Aspect N)
In (Aspect A) to (Aspect M), the stacking tray is a temporary stacking tray on which a plurality of sheets are temporarily stacked, and a binding unit such as a stapler 50 that performs binding processing on the plurality of stacked sheets, and a binding unit. This is a staple tray 21 provided with discharge means such as a discharge claw 29 for discharging a sheet bundle that has been bound by the means.

(Aspect O)
An image forming apparatus including an image forming unit 100 that forms an image on a sheet and a sheet processing unit that performs processing on a sheet on which an image is formed in the image forming unit. The sheet processing apparatus of (Aspect N) is employed. According to this, the same effects as those of the sheet processing apparatus according to (Aspect A) to (Aspect N) can be obtained. In addition, it is possible to provide an image forming apparatus that can perform sheet alignment with an inexpensive configuration.

DESCRIPTION OF SYMBOLS 1 Introduction conveyance path 2 Upper conveyance path 3 Straight conveyance path 4 Lower conveyance path 5 Paper discharge tray 6 Proof trays 7 and 8 Branching claw 10 Inlet roller pair 11 Conveyance roller pair 12 Conveyance roller pair 13 Inlet sensor 21 Staple tray 22 Jogger fence 24 Rear end fence 25 Paper sensor 26 Paper discharge roller 27 Driven roller 28 Paper discharge sensor 29 Release claw 30 Timing belt 32 Paper discharge guide 50 Stapler 100 Image forming unit 200 Paper processing device 400 Clamp unit 401 Clamp 402 Clamp guide 404 Link rotation center 405 Link 501 Base 503 Opening / closing section 504 Torsion spring 505 Solenoid 506 Center of rotation 700 Paper pressing means 701 Pressing member 702 Compression spring 703 Cam 800 Flexible rotating member 801 Holder 802 Rubber plate 80 Shaft 804 Pulley 805 Belt 806 Drive source 807 Detection plate 808 Sensor 850 Roller rotating mechanism 851 Roller roller 852 Roller rotating shaft 853 Roller rotating arm 855 Carriage 856 Carriage guide 857 Carriage belt 858 Carriage belt drive source 900 Paper leading edge pushing means 901 Push Member 902 Timing belt 903 Pulley B Paper punching unit P Paper P ′ Paper bundle

JP 2011-0773805 A Japanese Patent No. 4468140

Claims (11)

A sheet conveying unit configured to convey a sheet; a sheet holding unit configured to grasp and move an end of the sheet conveyed by the sheet conveying unit; and a stacking tray capable of stacking a plurality of sheets. In the paper processing apparatus for stacking the paper on the stacking tray by releasing the paper from the paper gripping means on the tray,
Paper detecting means for detecting that the trailing end of the paper in the transport direction has moved to a predetermined position of the stacking tray, and paper pressing means for pressing the paper on the stacking tray ,
When it is detected by the paper detection means that the trailing edge of the paper gripped by the paper gripping means has moved, the paper gripping means is stopped and the paper is pressed by the paper pressing means. , the sheet processing apparatus characterized in that a control means for controlling so as to release the grip of the paper by the paper gripping means. The sheet processing apparatus according to claim 1,
The above stacking tray, the sheet processing apparatus characterized in that a abutment member conveying direction after the end of the paper by the paper gripping means abuts. In the sheet processing apparatus according to 請 Motomeko 1,
The paper processing apparatus, wherein the paper pressing means is a flexible rotating member. A sheet conveying unit configured to convey a sheet; a sheet holding unit configured to grasp and move an end of the sheet conveyed by the sheet conveying unit; and a stacking tray capable of stacking a plurality of sheets. In the paper processing apparatus for stacking the paper on the stacking tray by releasing the paper from the paper gripping means on the tray,
A sheet detecting means for detecting that the rear end of the sheet in the transport direction has moved in preparation for a predetermined position of the stacking tray;
Control means for controlling the paper gripping means to release the gripping of the paper when the paper detection means detects that the rear end of the paper in the transport direction has moved;
A sheet pressing means for pressing the sheet conveyed on the stacking tray;
The paper pressing device has a pressing roller that can be moved up and down, and lowers and presses the pressing roller against the paper held by the paper holding device. The sheet processing apparatus according to claim 4 , wherein
The above stacking tray, the sheet processing apparatus characterized in that a abutment member conveying direction after the end of the paper by the paper gripping means abuts. In the paper processing apparatus according to claim 4 or 5 ,
A sheet processing characterized in that the pressing roller is lowered to the sheet gripped by the sheet gripping means in a state in which the pressing roller is rotated in a direction opposite to the transport direction of the transported sheet. apparatus. In the paper processing apparatus according to any one of claims 4 to 6 ,
A paper processing apparatus, wherein the paper gripping means is released before or after the paper gripping means is released, and the pressing roller is raised and separated from the paper. In the paper processing apparatus according to any one of claims 4 to 7 ,
The sheet processing apparatus according to claim 1, wherein a position where the pressing roller is lowered is a position on a leading end side of sheets stacked on the stacking tray. In the paper processing apparatus according to any one of claims 4 to 8 ,
The presser roller is movable in the transport direction of the paper transported on the stacking tray. The presser roller is moved based on the paper size information of the paper and is gripped by the paper gripping means. A sheet processing apparatus, wherein the pressing roller is lowered onto the sheet. In the paper processing apparatus according to any one of claims 1 to 9 ,
The stacking tray is a temporary stacking tray on which a plurality of sheets are temporarily stacked, a binding unit that performs binding processing on the stacked plurality of sheets, and a sheet bundle that is bound by the binding unit is discharged. A sheet processing apparatus, comprising: a staple tray including a discharge unit. An image forming apparatus comprising: an image forming unit that forms an image on a sheet; and a sheet processing unit that performs processing on a sheet on which an image is formed in the image forming unit.
Image forming apparatus characterized by employing a sheet processing apparatus according to any one of claims 1 to 10 as the sheet processing unit.

Images