JP2019182613A - Sheet processing apparatus and image forming system - Google Patents

Abstract

To provide a sheet processing apparatus and image forming system adapted to relieve the load in transport due to curling of a sheet and improve the alignment of sheets in stacking.SOLUTION: A sheet processing apparatus 70, for forming a sheet bundle S on a processing tray 74, performing post-processing such as bind-processing at a staple bind-processing unit 76 and discharging the sheet bundle S onto a stack tray 171, is provided with a press member 170 that pushes a front end of a sheet loaded on the processing tray 74 toward the stack tray 171. In the case that the front end of the sheet loaded on the processing tray 74 is curled in a direction away from the stack tray 171, the press member 170 moves from a retracted position to a press position and pushes the front end of the sheet toward the stack tray 171.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a sheet processing apparatus and an image forming system for stacking sheets printed by an image forming unit such as an inkjet method.

  2. Description of the Related Art Conventionally, sheet processing apparatuses that perform sheet processing such as alignment processing and binding processing on a plurality of sheets on which images are formed by an image forming apparatus such as a copying machine, a printer, and a facsimile are known. These sheet processing apparatuses temporarily stack the conveyed sheets on the processing tray, perform alignment processing, binding processing, and the like, and then discharge the processed sheet bundle to the stack tray.

  In such an apparatus, when sheets are stacked on the processing tray, if the sheets are curled, stacking is hindered. Therefore, in Patent Document 1, a front end pressing member that restricts the front end side of the sheet (the end on the downstream side in the sheet conveying direction) and a rear end pressing member that restricts the rear end side of the sheet are provided in order to suppress curling of the sheet. A configuration is disclosed.

JP2013-193870A

  The tip pressing member described in Patent Document 1 is biased by a spring so as to press the sheet from the upper side to the lower side of the sheets stacked on the processing tray. In such a configuration, as the curled sheets are accumulated on the processing tray, the interval between the processing tray and the leading edge pressing member is narrowed, and a conveyance load is created by closing the conveyance path of the sheet conveyed subsequently. There is a possibility. SUMMARY OF THE INVENTION An object of the present invention is to reduce a conveyance load due to sheet curling and to improve sheet alignment during stacking.

  In order to achieve the above object, a sheet processing apparatus of the present invention is a sheet processing apparatus that receives a sheet subjected to printing processing by an image forming apparatus, forms a sheet bundle, and discharges the sheet bundle. A sheet discharge unit that discharges the sheet in a predetermined discharge direction, a first sheet placement unit that places the sheet discharged by the sheet discharge unit, and the sheet supported by the first sheet placement unit A sheet bundle forming unit that forms a sheet bundle including the sheet bundle, a sheet bundle moving unit that moves the sheet bundle formed by the sheet bundle forming unit in a predetermined movement direction, and a sheet bundle moved by the sheet bundle moving unit A second sheet placing means, a pressing means for pressing the downstream end of the sheet placed on the first sheet placing means in a direction approaching the second sheet placing means, and a pressing means, Sheet A drive unit that moves between a pressing position to be pressed and a retracted position that is retracted in a direction away from the second sheet placing unit with respect to the pressing position; and a downstream side in the discharge direction of the sheet placed on the first sheet placing unit And a curling presence / absence judging means for judging whether or not the end portion of the sheet curls in a direction away from the second sheet placing means and a control means for controlling the driving means. When it is determined that the end on the downstream side in the discharge direction of the sheet placed on one sheet placing means is curled in a direction away from the second sheet placing means, the pressing means is moved from the retracted position to the pressing position. It is characterized by.

  The sheet processing apparatus of the present invention is a sheet processing apparatus that receives a sheet that has been subjected to printing processing by the image forming apparatus, forms a sheet bundle, and discharges the sheet. Paper discharge means for discharging in the direction, first sheet placement means for placing the sheets discharged by the paper discharge means, and a sheet bundle including the sheets in a state where the first sheet placement means supports the sheets. A sheet bundle forming means to be formed, a sheet bundle moving means for moving the sheet bundle formed by the sheet bundle forming means in a predetermined movement direction, and a second sheet stack for placing the sheet bundle moved by the sheet bundle moving means A pressing unit that presses the sheet, a pressing unit that presses the downstream end of the sheet placed on the first sheet placing unit in a direction approaching the second sheet placing unit, and a pressing unit that presses the sheet. position A drive unit that moves between a retracted position that is retracted in a direction away from the second sheet placing unit relative to the pressing position, an alignment unit that aligns the sheets placed on the first sheet placing unit, and a drive unit; Control means for controlling the aligning means, and the control means moves the pressing means from the retracted position to the pressing position after performing the aligning operation on the sheet by the aligning means.

  The sheet processing apparatus of the present invention reduces the load of transporting subsequently transported sheets by pressing the leading end of the sheet placed on the processing tray with a pressing unit, and improves the sheet alignment during stacking. be able to.

1 is a cross-sectional view of an overall configuration of an image forming system according to an embodiment. The perspective view of the post-processing unit of this embodiment. The operation | movement figure of the post-processing unit of this embodiment. The operation | movement figure following FIG. 3 of the post-processing unit of this embodiment. The block diagram which shows the control structure of this embodiment. 6 is a modified example of the overall configuration of the image forming system of the present embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the accompanying drawings, the same or similar components are denoted by the same reference numerals throughout the present specification.

  FIG. 1 schematically shows the overall configuration of an image forming system including a sheet processing apparatus according to the present invention. As shown in FIG. 1, the image forming system 100 includes an image forming apparatus A and a sheet processing apparatus B provided therewith. The image forming apparatus A includes a paper feeding unit 10, an image forming unit 20, and an image reading unit 30. The sheet processing apparatus B includes a relay conveyance unit 60 and a sheet post-processing unit 70.

<Paper feed unit>
The sheet feeding unit 10 is provided on the lower side of the image forming apparatus A, and includes a plurality of cassette mechanisms 10a, 10b, 10c, and 10d that store image forming sheets of different sizes. The sheet having the size specified from the sheet is fed out to the sheet feeding path P1. Each of the cassette mechanisms 10a, 10b, 10c, and 10d is detachably installed from the paper feeding unit 10, and includes a separation mechanism that separates the internal sheets one by one and a paper feeding mechanism that feeds out the sheets.

  A large capacity cassette 10e and a manual feed tray 10f are connected to the paper feed path P1. The large-capacity cassette 10e and the manual feed tray 10f are provided on one side of the apparatus housing 1 (on the right side in FIG. 1), and the apparatus housing 1 has a corresponding sheet supply port (feeding opening). 16 and 17 are provided. The large-capacity cassette 10e is composed of an optional unit that stores sheets of a size that is consumed in large quantities. The manual feed tray 10f is configured to be able to supply special sheets such as cardboard sheets, coating sheets, and film sheets that are difficult to separate and feed.

  A pair of conveying rollers for feeding sheets supplied from the cassette mechanisms 10a, 10b, 10c, 10d and the large-capacity cassette 10e (via the paper feed paths P1a, P1e, etc.) to the paper feed path P1 downstream. 11 and a registration roller pair 12 for aligning the leading edges of the sheets at the end of the path.

  Each of the cassette mechanisms 10a, 10b, 10c, 10d and the large-capacity cassette 10e is provided with a pickup roller 13 and a conveying roller pair 14, respectively, and supplies sheets one by one to the sheet feeding path P1. In the apparatus housing 1, a conveyance roller pair 15 is provided in the vicinity of the sheet supply port 17 of the manual feed tray 10 f, and conveys the sheet manually supplied by the user toward the registration roller pair 11.

<Image forming unit>
The image forming unit 20 is provided on the transport path P2 above the cassette mechanism 10a and includes, for example, an ink jet printing unit. The image forming unit 21 is provided at a position facing the conveyance belt 22 across the conveyance path P2. The image forming unit 21 prints by applying a liquid such as ink onto the sheet conveyed by being supported by the conveyance belt 22 along the conveyance path P2, thereby causing the liquid to adhere to the sheet. The image forming unit 21 according to the present exemplary embodiment includes a line head that can simultaneously eject ink across a width direction intersecting (orthogonal) with the sheet conveyance direction.

  The image forming unit of the present application is not limited to the ink jet system. For example, the image forming unit is an electrostatic printing mechanism, and includes a rotating photosensitive drum, a light emitting device that emits an optical beam, and a developing device disposed around the photosensitive drum. It is good also as a structure provided with the cleaner. In that case, a latent image is optically formed on the photosensitive drum by a light emitter, and toner is adhered to the latent image using a developing device. In accordance with the timing of image formation on the photosensitive drum, the sheet is conveyed to a conveyance path P2, the image is transferred onto the sheet by a transfer charger, and is fixed by a fixing roller disposed on the downstream side in the sheet conveyance direction.

  The sheet subjected to the image forming process is conveyed to a sheet reversing path P3, a conveyance path P4 for discharging to the first discharge unit 40a, or a conveyance path P5 for conveying to the relay conveyance unit 60. In the path switching unit 23, a flapper guide (not shown) moves according to the sheet conveyance destination, and guides the sheet to one of the conveyance paths P3, P4, and P5.

  The sheet reversing path P3 is a conveyance path for reversing the front and back of the sheet. The sheet reversing path P3 is used for double-sided printing, or is used for single-sided printing. It is used when transported to the processing device 70.

  The conveyance path P4 is a conveyance path for discharging the sheet to the first discharge unit 40a. When discharging the sheet to the first discharge unit 40a, the sheet is transferred from the conveyance path P2 to the conveyance path P4 by the path switching unit 23, and the printed surface of the sheet (the surface printed second time in the case of double-sided printing). The sheet is discharged to the sheet placement surface (mounting portion) 41 in a face-down state facing downward. The conveyance path P4 is curved upward (like a circular arc) from the substantially horizontal conveyance path P2 with the path switching unit 23 as a starting point, and from there to the sheet discharge port 24 (provided in the apparatus housing 1). It is formed as follows.

  When the sheet is conveyed to the relay conveyance unit 60, the path is not switched by the path switching unit 23, and the sheet is conveyed straight along the conveyance path P2. When the sheet is conveyed to the relay conveyance unit 60, if the sheet is conveyed face up (with the printing surface of the sheet facing up), the sheet is conveyed face down without performing the reversing process by the sheet reversing path P3. In this case, the sheet is reversed and conveyed using the sheet reversal path P3.

<Image reading unit>
The image reading unit 30 is provided above the first discharge unit 40a and the conveyance path P4, and includes an image reading unit 33 that reads an image of a document, a document feed tray 31 on which a document to be fed is placed, and an image. A document discharge tray 32 from which a document read by the reading unit 33 is discharged. The image reading unit 30 photoelectrically converts the document image read by the image reading unit 33 into image data and outputs the image data to the image forming unit as an electrical signal. It should be noted that the image of the document may be read using a platen on which the document is placed, a carriage that reciprocates along the platen, and an image reading unit 33 provided on the carriage.

<Relay transport unit>
The relay conveyance unit 60 is a unit for conveying the sheet subjected to the image forming process by the image forming unit 20 to the post-processing unit 70 side, and has a path switching unit 61. The path switching unit 61 includes a conveyance path P5 for discharging the sheet to the stack tray 171 (third discharge unit 40c) of the post-processing unit 70, and a sheet placement surface 71a on the upper surface of the unit housing 71 of the post-processing unit 70. The transport path is switched between the transport path P6 for discharging to the (second discharge section 40b).

  Switching between the stack tray 171 and the sheet placing portion 71a is switched depending on whether post-processing such as binding processing is performed on the sheets. In this embodiment, since the sheet is discharged straight to the sheet placement surface 71a, the sheet is discharged to the first discharge unit 40a when the sheet is discharged face down, and to the second discharge unit 40b when the sheet is discharged face up. The modes may be divided so as to be discharged. When the discharge roller 63 provided in the conveyance path P6 is configured to be movable in a direction orthogonal to the sheet conveyance direction, the second discharge unit 40b shifts the sheet in the width direction (direction orthogonal to the conveyance direction). By doing so, the jog can be discharged.

<Post-processing unit>
The post-processing unit 70 is a unit that performs post-processing such as binding processing on the sheet received from the relay conveyance unit 60. The post-processing unit of the present embodiment is equipped with a sheet binding processing mechanism that forms a sheet bundle by stacking and stacking a plurality of conveyed sheets and binding the sheet bundle.

  The post-processing unit 70 includes a sheet supply port 72, a conveyance path P15, a paper discharge roller 73, a processing tray 74, sheet carry-in members 75a and 75b, a staple binding processing unit 76, a sheet end regulating member 77, a sheet width, and a unit housing 71. The alignment member 79 and the bundle discharge member 78 are stored, and a swingable sheet pressing member 170 and a vertically movable stack tray 171 are provided on the opposite side of the sheet supply port 72.

  The sheet carry-in member is composed of a paddle 75a and a belt 75b, and a direction in which the rear end of the sheet on the processing tray 74 (the upstream end in the sheet conveyance direction conveyed by the sheet discharge roller 73) abuts against the sheet end regulating member 77. This is a member for conveying the sheet. Each of the paddle 75a and the belt 75b is configured to be movable between a retracted position separated from the seat and an operating position that rotates in contact with the seat, and rotates the counterclockwise in FIG. 3 at the operating position. Transport.

  The width aligning member 79 is composed of a pair of movable aligning members on both sides of the sheet in the sheet width direction. The sheet is placed in contact with the retreat position spaced from the edge in the sheet width direction and the edge in the sheet width direction. It is configured to be movable between operating positions that are moved in the width direction. The alignment members on both sides are not necessarily moved. One alignment member may be a fixed restricting member, and only the other aligning member may be moved to perform sheet width alignment with respect to the fixed restricting member. . The other alignment member does not need to move in contact with the edge in the sheet width direction, but includes a member that can move in the sheet width direction by contacting the upper surface of the sheet, or a roller member that conveys the sheet in the sheet width direction. By providing, sheet width alignment operation is possible.

  The staple binding processing unit 76 performs a binding process on the sheet bundle aligned and stacked on the processing tray 74 in the sheet conveyance direction and the sheet width direction. The staple binding processing unit 76 is configured to be movable in the sheet width direction, and can perform binding processing at a predetermined position of the sheet edge that contacts the corner portion of the sheet bundle or the sheet end regulating member 77. In this embodiment, a staple binding mechanism using staple needles is employed. However, a needleless binding mechanism that does not use staple needles may be employed, and the needle binding mechanism and the needleless binding mechanism are post-processed respectively. They may be provided on the front side and the rear side of the unit 70, respectively, so as to switch between needle binding and needleless binding according to user settings.

  The bundle discharge member 78 discharges the sheet bundle on the processing tray 74 to the stack tray 171 by pushing out the trailing edge of the sheet bundle. The bundle discharging member 78 is retracted below the processing tray 74 until the sheet bundle is formed, and after the sheet bundle is formed on the processing tray 74 (after performing the binding processing when performing the binding processing). ) It is configured to move along the guide member 78a so as to contact the trailing edge of the sheet bundle and push the sheet bundle toward the stack tray 171.

  Details of the configurations of the paper discharge roller 73, the processing tray 74, the sheet carry-in members 75a and 75b, the staple binding processing unit 76, the sheet end regulating member 77, the sheet width aligning member 79, and the bundle discharge member 78 described so far are as follows. For example, it is described in JP-A-2015-16970 and the like, and various post-processing units such as needleless binding, punching (punching), folding processing, and the like can be applied. Further, it is possible to shift the sheet in the width direction (a direction orthogonal to the sheet conveying direction) and discharge it to the stack tray 171 without performing the binding process, and this can also be included in the post-processing. Shifting the sheet in the width direction can be achieved by changing the alignment position by the width alignment member 79 or changing the sheet discharge position by a mechanism in which the discharge roller pair 73 shifts in the sheet width direction.

  The post-processing unit 70 according to the present embodiment has a curled sheet end portion (mainly sheet leading end: an end portion on the downstream side in the sheet conveying direction when the sheet is discharged from the processing tray 74 toward the stack tray 171) downward. A pressing member 170 for pressing is provided.

  Since the image forming unit 20 of the present embodiment is an inkjet system, the post-processing unit 70 is particularly suitable for a sheet with a large ink discharge amount and a high printing rate (for example, when a dark color image is printed on almost the entire surface of the sheet). When it is conveyed to the surface, curling occurs. The curl direction of the sheet includes an upper curl (the state of the sheet S1 in FIG. 3A) and a lower curl (the state of the sheet S1 in FIG. 4B). When the upper curled sheet continues, the processing tray 74 and The space above the sheet placed on the processing tray 74 is blocked by the curled sheet, which may hinder the conveyance of subsequent sheets and may deteriorate the alignment of the sheet bundle (specifically, May increase the transport load of the succeeding sheet, which may cause a jam or the succeeding sheet may shift the already stacked sheet). Therefore, the post-processing unit 70 according to the present embodiment follows the pressing tray 170 to press the upper curled sheet to secure the space above the processing tray 74 and the sheet placed on the processing tray 74. There is no hindrance to the conveyance of the sheet.

  The pressing member 170 is configured by a plate-like member (pressing surface 170a) having a predetermined width so that both the side edge of the minimum size sheet and the side edge of the maximum size sheet can be pressed in the sheet width direction. . The pressing surface 170a is configured to be swingable about the swinging shaft 170b. The pressing surface 170a moves between a pressing position where the pressing surface 170a approaches the stack tray 171 and a retracted position where the pressing surface 170a moves away from the stack tray 171. A drive member (not shown) such as a solenoid or a motor is provided.

  This pressing position is a position where the front end of the pressing surface 170 a is positioned below (the stack tray 171 side) the extension line 74 a (broken line) of the sheet placement surface of the processing tray 74. By pressing the sheet to this position, the upper curl of the sheet is transformed into the lower curl. Further, the pressing surface 170 a at the pressing position is positioned in a space secured by a step between the processing tray 74 and the stack tray 170. Accordingly, the sheet rear end side is supported by the processing tray 74, and the pressing surface 170a presses the sheet leading end below the extension line 74a of the sheet placing surface of the processing tray 74, so that the fixing is performed as in the past. The upper curl can be suppressed as compared with the guide member that guides the sheet curled at the position. Thereby, when forming a sheet bundle on the processing tray 74, a conveyance failure does not occur, and alignment is improved. Note that the pressing surface 170a does not necessarily need to be positioned below the extension line 74a of the sheet placement surface at the pressing position, as long as at least the leading end of the sheet is positioned below the extension line 74a of the sheet placement surface. .

  Hereinafter, the processing operation from the sheet bundle formation to the bundle discharge by the post-processing unit 70 (mainly the operation timing of the pressing member 170) will be described with reference to FIGS. FIG. 3A shows a state in which the first sheet S1 is being conveyed along the conveyance path P5. The sheet S1 is discharged to the processing tray 74 by the paper discharge roller 73. At this time, the paddle 75a and the belt 75b, which are sheet carry-in members for abutting the rear end of the sheet S1 against the sheet end regulating member 77, are positioned at the retracted position retracted from the processing tray 74. The pressing member 170 is also retracted to the above-described retracted position.

  After the trailing edge of the sheet S1 passes the sheet discharge roller 73, the paddle 75a moves to an operating position where the sheet S1 contacts the sheet S1, and the paddle 75a rotates counterclockwise in FIG. It is conveyed toward the regulating member 77 (FIG. 3B).

  Thereafter, the belt 75b moves to the operating position where it contacts the sheet S1, and the belt 75b rotates counterclockwise in the same manner as the paddle 75a, so that the rear end of the sheet S1 is reliably abutted against the sheet end regulating member 77. (FIG. 3C).

  After aligning the sheet S1 with the paddle 75a and the belt 75b in the sheet conveying direction, the paddle 75a moves to the retracted position, and the width aligning member 79 is in the direction (sheet width direction) perpendicular to the conveying direction of the sheet S1. The sheet S1 is moved from the retracted position away from S1 to the operating position that contacts the edge of the sheet S1, and the width of the sheet S1 is aligned (FIG. 3D).

  In the present embodiment, the belt 75b can move in the sheet width direction accurately by continuing the sheet scraping operation at the operating position even during the sheet width aligning operation.

  When the sheet width alignment is completed, the width alignment member 79 regulates both end edges of the sheet S1, and the belt 75b rotates in the counterclockwise direction while pressing the upper surface of the sheet S1. 3 (D)) moves to the pressing position and presses the leading end of the sheet S1 downward (FIG. 4 (A)). In this manner, the pressing member 170 presses the leading end of the sheet in a state where the sheet on the processing tray 74 is regulated in the sheet width direction, the sheet conveyance direction, and the sheet surface direction by the width aligning member 79 and the belt 75b, thereby the processing tray 74. The upper curling of the sheet can be suppressed without deteriorating the upper sheet alignment. Note that the sheet width alignment process may be performed after the leading end of the sheet S1 is pressed by the pressing member 170, but it is desirable to perform the pressing process while regulating the upper surface of the sheet. In other words, the pressing member 170 presses the front end of the sheet after the alignment operation in the sheet conveyance direction and / or the sheet width direction, thereby suppressing the upper curling of the sheet without deteriorating the sheet alignment on the processing tray 74. it can.

  The next sheet S2 is conveyed in a state where the upper curl of the sheet S1 is deformed to the lower curl by this pressing process (FIG. 4B). At this time, since the sheet S1 curled up does not exist in the space where the sheet S2 on the upper side of the processing tray 74 is conveyed, the sheet S2 is not jammed and the position of the sheet S1 is not shifted. 74 can be accepted.

  In this way, the sheet bundle S is formed on the processing tray 74 by repeating the operations from FIG. 3A to FIG. 4B (FIG. 4C), and in this state, the staple is applied to the sheet bundle S. A binding process is performed by the binding processing unit 76. When the binding process is completed, the sheet bundle S is discharged onto the stack tray 171 by the sheet bundle pushing member 78, and a series of operations is completed.

  The post-processing unit 70 (and the relay conveyance unit 60) of this embodiment is installed on the mounting table 50 on the side of the image forming apparatus 100. The mounting table 50 includes an installation unit 51, a leg unit 52, and an opening 53, and is fixed by hooking a hook member 54 provided on the side of the image forming apparatus 100 to the opening 53. The installation unit 51 is provided with a slide rail (not shown), and the post-processing unit 70 is configured to be slidable in the left-right direction in FIG. When the post-processing unit 70 (and the relay conveyance unit 60) is separated from the image forming apparatus 100, it is possible to perform jam removal processing when a sheet is jammed.

  When the post-processing unit 70 moves to the front end side of the installation unit 51, force is applied in the counterclockwise direction with respect to the mounting table 50, but the leg unit 52 is supported by the hook member 54 and the side surface 1 c of the image forming apparatus 100. Therefore, the pedestal 50 will not fall down.

<Discharge unit>
In the present embodiment, a plurality of discharge units that discharge processed sheets are provided. As described above, the first discharge unit 40a discharges the sheet that has been subjected to the image forming process by the image forming unit 20 straight down face-down, or reverses the front and back of the sheet in the sheet reverse path P3 and discharges the sheet face-up. It is a discharge part. The first discharge unit 40 a is a so-called in-body discharge unit of the image forming apparatus A, and includes a space defined by the standing surface 1 a, the ceiling surface 1 b, and the placement surface 41 of the apparatus housing 1.

  The second discharge unit 40b is a discharge unit that uses the unit housing upper surface 71a of the post-processing unit 70, and discharges the sheet image-formed by the image forming unit 20 straight-up with face-up or the sheet reversal path P3. Turn the front and back to face down. In other words, the first discharge unit 40a and the second discharge unit 40b can be discharged to either by the user's setting, but considering the productivity, in the case of face down, the first discharge unit 40a is faced up. In such a case, it is desirable to discharge to the second discharge unit 40b.

  It is also possible to sort out whether the ink is discharged to the first discharge portion 40a or the second discharge portion 40b according to the amount of ink (printing rate) attached to the sheet by the image forming processing by the image forming portion 20. For example, since it is not necessary to dry the ink adhering to the sheet when the printing rate is low, as described above, the ink is discharged as it is to the first discharge unit 40a in the case of face down and to the second discharge unit 40b in the case of face up. . However, since it is necessary to dry the ink adhering to the sheet when the printing rate is high, the sheet is dried by temporarily transporting the sheet to the sheet reversing path P3 and taking time to discharge. After the sheet is conveyed through the sheet reversing path P3, the face-up sheet is discharged to the first discharge unit 40a, and the face-down sheet is discharged to the second discharge unit 40b. In addition, if a drying member such as a fan is provided in the sheet reversing path P3, the drying effect can be further enhanced.

  The third discharge unit 40c is a stack tray 171 of the post-processing unit 70, and the sheets post-processed by the post-processing unit 70 are discharged. The stack tray 171 is configured to be movable up and down, and moves up and down according to the sheet stacking amount. In addition, since the post-processing unit 70 according to the present embodiment has a mechanism for shifting the sheet in the width direction, the sheet is discharged in a state in which the sheet is shifted in the width direction on the stack tray 171 without performing the staple binding process. Can be made.

  Further, in this embodiment, a configuration is disclosed in which processing by the post-processing unit 70 is performed on a sheet with a high printing rate as described above. However, a sheet with a higher printing rate (for example, a full-color solid image having a dark color) Since the printed sheet) cannot be processed by the post-processing unit 70, such a sheet may be discharged to the first discharge unit 40a or the second discharge unit 40b.

  Further, when post-processing is performed by the post-processing unit 70, productivity is reduced as compared with straight discharge. Therefore, even in the productivity-oriented mode, the first discharge unit 40a or the second discharge unit 40b may be discharged.

<Control configuration>
FIG. 5 is a diagram showing a control configuration of the image forming system 100 of the present embodiment. The image forming apparatus A and the sheet processing apparatus B have control CPUs 81 and 87, respectively, and can exchange information with each other. The first control CPU 81 on the image forming apparatus A side is connected to the image formation control unit 82, the first drive control unit 83, the reading control unit 84 and the first signal control unit 85. The first control CPU 81 sends the print data received from the reading control unit 84 to the image formation control unit 82, and the image formation control unit 82 controls the image formation unit (print head) 21 to perform image formation processing. Further, the first control CPU 81 issues a command to the first drive control unit in accordance with input information (detection of the sheet end portion, etc.) from various sensors connected to the first signal control unit 85, and the roller for conveying the sheet. The sheet is conveyed by controlling the driving motor and the flapper guide driving unit. The first control CPU 81 is connected to an input unit 86 for inputting information such as a print mode, a discharge mode, and a post-processing mode from the user, and controls each control unit according to the input information. The mode information is transmitted to the second control CPU 87 of the sheet processing apparatus B.

  From the input unit 86, “image formation mode” and “post-processing mode” are set. The image forming mode sets mode settings such as color / monochrome printing, duplex / single-sided printing, and image forming conditions such as sheet size, sheet paper quality, number of printouts, and enlarged / reduced printing. The “post-processing mode” is set to, for example, “print-out mode”, “staple binding processing mode”, “eco-binding processing mode”, “jog sorting mode”, or the like. The illustrated apparatus is provided with a “manual binding mode”, and in this mode, the sheet bundle binding processing operation is executed off-line separately from the first control CPU 81 of the image forming unit A.

  The second control CPU 87 on the sheet processing apparatus B side is provided in the post-processing unit 70, and the second control CPU 87 controls not only the post-processing unit 70 but also the relay conveyance unit 60. The second control CPU 87 is connected to the second drive control unit 88 and the second signal control unit 89, and the second control CPU 81 receives input information (sheet edge) from various sensors connected to the second signal control unit 89. In response to the detection of the part, etc., a command is issued to the second drive control unit, and the sheet is conveyed by controlling the driving motor of the roller for conveying the sheet and the flapper guide driving unit. The second drive control unit 88 is also connected to the binding drive control unit, the width matching drive control unit, and the pressing member drive control unit, and executes a post-processing operation and a pressing operation.

  Further, the first control CPU 81 transfers the post-processing mode, the number of sheets, the number of copies information, the paper thickness information of the sheet on which the image is formed, and the like to the second control CPU 87. At the same time, the first control CPU 81 transfers a job end signal to the second control CPU 87 every time image formation is completed. In the present embodiment, print information, in particular, information on the ejection amount of ink for the sheet (print rate information) is transferred to the second control CPU 87. The print information includes image information read by the image reading unit C, or an ink discharge amount calculated from the image information, in addition to the ink discharge amount on the sheet. Here, the above-described printing rate can be obtained from the area of the image data with respect to the sheet size. Therefore, a high print rate is determined to be high because, for example, image data exists in 70% of the entire sheet and there are many portions where ink is ejected from the sheet.

<Pressing conditions>
In the post-processing unit 70 of the present embodiment, the pressing process by the pressing member 170 described above may be performed on all sheets, but the pressing process is performed only when the curl of the sheet conveyed to the processing tray 74 is large. And processing efficiency is good.

  Therefore, the post-processing unit 70 of the present embodiment is provided with “curl presence / absence determination means”, which determines whether or not the sheet on the processing tray 74 is curled by a predetermined amount or more. When it is determined that the curl is greater than a predetermined amount, the pressing process by the pressing member 170 is performed.

<Curl presence determination means>
Several methods for determining the presence / absence of curling are conceivable, and all of the configurations shown below are included in the curling presence / absence judging means.
(1) The second control CPU 87 receives from the first control CPU the above-described printing information such as the amount of ink discharged to the sheet and the sheet type (mainly thickness) information, and the printing rate (sheet area) exceeds a predetermined threshold. If the sheet is thinner than a predetermined threshold value (the sheet type may be preset), the second control CPU 87 sets the sheet to a predetermined amount or more. Judge that it is curled. Note that the sheet thickness information may or may not be considered.
(2) An imaging member (such as a camera (not shown)) that captures the upper portion of the processing tray 74 is provided, and it is detected from the image information of the sheet that has been discharged to the processing tray 74 that a sheet curled upward is present at a predetermined position. In this case, the second control CPU 87 determines that the sheet is curled by a predetermined amount or more.
(3) When a contact-type sensor member (not shown) is provided on the lower surface of the pressing surface 170a of the pressing member 170 or below the swing shaft 170b, and the sensor member detects the sheet discharged to the processing tray 74, the second control is performed. The CPU 87 determines that the sheet is curled by a predetermined amount or more. If a distance measuring sensor that measures the distance to the sheet on the processing tray 74 is provided instead of the contact type sensor member, and the distance from the sheet is shorter than the predetermined distance, the sheet is curled to a predetermined amount or more. You may judge.

<Modification>
FIG. 6 shows a modification of the relay conveyance unit 60. As shown in FIG. 6, when a path switching unit 23 that switches the path from the transport path P2 to the transport path P4, the transport path P5, or the transport path P6 is provided in the image forming apparatus 100, the transport path P5 and the transport path What is necessary is just to provide the relay conveyance unit 60 so that it may each connect with the exit of the path | pass P6. In this case, the transport path P6 is a straight path that continues from the transport path P2.

  In the present embodiment, the configuration in which the sheet leading edge is pressed by the pressing member 170 after the sheet S1 is placed on the processing tray 74 is shown, but the sheet leading edge is in the middle of being conveyed by the sheet discharge roller 73. At the timing when the pressing member 170 is reached, the pressing member 170 may be moved from the retracted position to the pressing position to press the leading edge of the sheet, and then the pressing member 170 may be moved to the retracting position. In this case, since the leading edge of the sheet is pressed while the sheet is nipped by the sheet discharge roller 73, the sheet can be stiffened and the upper curl can be suppressed. Although a slight conveyance load is generated, the sheet alignment on the processing tray 74 is improved, which is more effective than the related art.

DESCRIPTION OF SYMBOLS 100 Image forming system A Image forming apparatus B Sheet processing apparatus 1 Apparatus housing 10 Paper feed unit 20 Image forming unit 30 Image reading unit 40a 1st discharge part 40b 2nd discharge part 40c 3rd discharge part 50 Stand 60 Relay conveyance unit 70 Back Processing unit 71 Unit housing 73 Paper discharge roller 74 Processing tray (first sheet placing means)
75a Paddle 75b Belt (second pressing means)
76 Staple binding processing section 77 Sheet end regulating member 78 Sheet bundle pushing member (sheet bundle moving means)
79 Width alignment member (width regulating means)
81 First control CPU
87 Second control CPU (control means, curl presence / absence judgment means)
170 Pressing member (pressing means)
170a Press surface 170b Oscillating shaft 171 Stack tray (second sheet placing means)

Claims (9)

In a sheet processing apparatus that receives a sheet that has undergone printing processing in an image forming apparatus, forms a sheet bundle, and discharges the sheet bundle,
A paper discharge means for discharging the sheet received from the image forming apparatus in a predetermined discharge direction;
First sheet placement means for placing the sheet discharged by the paper discharge means;
Sheet bundle forming means for forming a sheet bundle including the sheet in a state where the first sheet placing means supports the sheet;
Sheet bundle moving means for moving the sheet bundle formed by the sheet bundle forming means in a predetermined movement direction;
A second sheet placing means for placing the sheet bundle moved by the sheet bundle moving means;
A pressing means for pressing an end of the sheet placed on the first sheet placing means on the downstream side in the discharge direction in a direction approaching the second sheet placing means;
Driving means for moving the pressing means between a pressing position for pressing a sheet and a retracted position retracted in a direction away from the second sheet placing means than the pressing position;
Curl presence / absence judging means for judging whether or not the downstream end of the sheet placed on the first sheet placing means is curled in a direction away from the second sheet placing means;
Control means for controlling the drive means,
The control means determines that the end on the downstream side in the discharge direction of the sheet placed on the first sheet placing means is curled in a direction away from the second sheet placing means by the curl presence / absence judging means. In this case, the sheet processing apparatus moves the pressing unit from the retracted position to the pressing position. A second pressing unit that presses the upstream side of the sheet placed on the first sheet placing unit on the first sheet placing unit side with respect to the downstream end of the discharge direction;
The sheet processing apparatus according to claim 1, wherein the control unit moves the pressing unit from the retracted position to the pressing position while the sheet is pressed by the second pressing unit. Width regulating means for regulating the sheet placed on the first sheet placing means in a direction orthogonal to the moving direction;
The sheet processing apparatus according to claim 1, wherein the control unit moves the pressing unit from the retracted position to the pressing position with the width regulating unit regulating the sheet. The second sheet placing means is disposed so as to form a predetermined step with the first sheet placing means,
In the state where the pressing means is in the pressing position, an end portion on the downstream side in the discharge direction of the sheet placed on the first sheet placing means is an extension of the sheet placing surface of the first sheet placing means. The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is positioned closer to the second sheet placing unit than a line.   The part of the pressing means is positioned on the second sheet placing means side with respect to the extension line of the sheet placing surface of the first sheet placing means at the pressing position. Sheet processing equipment.   The curl presence / absence judging means has a receiving means for receiving information on ink ejection amount or printing rate for the sheet from the image forming apparatus, and the received ink ejection amount or printing rate is greater than a predetermined value. The sheet processing apparatus according to claim 1, wherein the sheet is determined to be curled.   The curl presence / absence judging means has a detecting means for detecting a curl of a sheet placed on the first sheet placing means, and placed on the first sheet placing means according to a detection result of the detecting means. 6. The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus determines whether or not the formed sheet is curled. In a sheet processing apparatus that receives a sheet that has undergone printing processing in an image forming apparatus, forms a sheet bundle, and discharges the sheet bundle,
A paper discharge means for discharging the sheet received from the image forming apparatus in a predetermined discharge direction;
First sheet placement means for placing the sheet discharged by the paper discharge means;
Sheet bundle forming means for forming a sheet bundle including the sheet in a state where the first sheet placing means supports the sheet;
Sheet bundle moving means for moving the sheet bundle formed by the sheet bundle forming means in a predetermined movement direction;
A second sheet placing means for placing the sheet bundle moved by the sheet bundle moving means;
A pressing means for pressing an end of the sheet placed on the first sheet placing means on the downstream side in the discharge direction in a direction approaching the second sheet placing means;
Driving means for moving the pressing means between a pressing position for pressing a sheet and a retracted position retracted in a direction away from the second sheet placing means than the pressing position;
Aligning means for aligning the sheets placed on the first sheet placing means;
Control means for controlling the drive means and the alignment means,
The sheet processing apparatus, wherein the control unit moves the pressing unit from the retracted position to the pressing position after performing the alignment operation on the sheet by the aligning unit. An image forming apparatus for forming an image on a sheet;
A sheet processing device that makes a sheet bundle a sheet sent from the image forming apparatus,
The image forming system, wherein the sheet processing apparatus is the sheet processing apparatus according to claim 1.

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