JP6341332B2 - Sheet post-processing apparatus and image forming system including the same - Google Patents

Description

  The present invention relates to a sheet post-processing apparatus that performs post-processing such as punch hole forming processing and binding processing on a sheet of paper or the like on which an image is formed by an image forming apparatus such as a copying machine, a facsimile, or a printer, and an image forming system including the same. About.

  Conventionally, a stacking process in which a plurality of sheets on which images are formed by an image forming apparatus such as a copying machine or a printer is stacked, and the bundle of stacked sheets is bound together by a staple, and a punch hole (perforation) by a punch hole forming apparatus A paper post-processing apparatus capable of executing punch hole forming processing for making a hole is used.

  In such a sheet post-processing apparatus, it is necessary to align and stack the sheet bundle when performing the binding process. For example, Patent Documents 1 and 2 disclose a sheet post-processing device including a pair of carry-in rollers that carries a sheet onto a processing tray and a pair of discharge rollers that discharges the sheet from the process tray to a discharge tray.

  The discharge roller pair is composed of a discharge roller and a discharge roller that is pressed against or separated from the discharge roller, and the paper is carried onto the processing tray by the pair of carry-in rollers in a state where the discharge roller and the discharge roller are separated from each other. Then, after the trailing edge of the sheet passes through the pair of carry-in rollers, the discharge roller and the discharge roller are pressed against each other and rotated in reverse. As a result, the sheets are drawn to the upstream side in the transport direction, and the sheet bundle on the processing tray is aligned by contacting the rear end regulating surface of the processing tray.

JP-A-9-156820 JP2013-224221A

  However, in the methods of Patent Documents 1 and 2, when the subsequent sheets are pulled in with the sheets already stacked on the processing tray, the entire stacked sheets are pulled in, and the consistency of the sheet bundle is increased. There was a problem of lowering.

  Specifically, as shown in FIG. 5, when the discharge roller pair 29 is reversely rotated and the paper P2 is drawn into the processing tray 30, both the discharge roller 29a and the discharge roller 29b constituting the discharge roller pair 29 are reversely rotated. In this case, the sheet bundle P1 that has already been abutted and aligned with the abutting portion 30a of the processing tray 30 may be simultaneously drawn. As a result, as shown by the broken line in FIG. 5, the sheet bundle P1 is bent, and the consistency of the sheet bundle may be lowered.

  In view of the above problems, the present invention includes a sheet post-processing apparatus capable of preventing misalignment of a sheet bundle when aligning the sheet bundle by pulling a sheet onto a processing tray using a pair of discharge rollers, and the same. An object is to provide an image forming system.

  In order to achieve the above object, the present invention is a sheet post-processing apparatus including a processing tray, a discharge tray, and a discharge roller pair. The processing tray receives and stacks a predetermined number of sheets. The discharge tray is disposed downstream of the processing tray in the sheet conveying direction, and the sheets stacked on the processing tray are discharged. The pair of discharge rollers includes a discharge roller that contacts the uppermost surface of the sheets stacked on the processing tray and a discharge roller that contacts the lowermost surface of the sheets stacked on the processing tray. The sheet post-processing apparatus discharges the sheet from the processing tray to the discharge tray by rotating the discharge roller pair forward, and reversely rotates the discharge roller in a state where the rotation of the discharge roller is stopped. Pull in.

  According to the first configuration of the present invention, when the sheet is drawn into the processing tray, only the discharge roller is reversely rotated in a state where the rotation of the discharge roller is stopped. And does not affect sheet bundles already aligned on the processing tray. Therefore, there is no possibility that the already aligned sheet bundle is drawn and bent together with the newly loaded sheet, and it is possible to effectively prevent a decrease in the consistency of the sheet bundle on the processing tray.

Schematic showing the internal configuration of the image forming apparatus 100 and the sheet post-processing apparatus 20 of the present invention. FIG. 2 is a partially enlarged view of the periphery of a processing tray 30 in the paper post-processing apparatus 20 in FIG. 1 and shows a state in which discharge rollers 29a are arranged at a separation position. FIG. 2 is a partially enlarged view around a processing tray 30 in the paper post-processing apparatus 20 in FIG. 1 and shows a state in which a discharge roller 29a is arranged at a contact position. In the sheet post-processing apparatus of the present invention, a side cross-sectional view showing a state in which the subsequent sheet P2 is pulled in a state where the sheet bundle P1 is stacked on the processing tray 40. Side sectional view showing a state in which a subsequent sheet P2 is pulled in a state where the sheet bundle P1 is stacked on the processing tray 40 in a conventional sheet post-processing apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, an image forming system including the image forming apparatus 100 and the sheet post-processing apparatus 20 of the present invention will be described with reference to FIG. FIG. 1 is a schematic diagram showing internal configurations of an image forming apparatus 100 and a sheet post-processing apparatus 20 according to the present invention. In the present exemplary embodiment, a multifunction peripheral is illustrated as an example of the image forming apparatus 100. However, the paper post-processing apparatus 20 of the present invention may be applied to a printer other than a digital multifunction peripheral, such as a laser printer, an inkjet printer, or a facsimile apparatus. Can be similarly connected.

  As shown in FIG. 1, the image forming apparatus 100 is a so-called in-body discharge type digital multi-function peripheral, and roughly includes a main body housing 2a and an upper housing 2b disposed on the main body housing 2a. ing. The upper housing 2b is provided with various mechanisms, which will be described later, for reading an image of an original as an electrical signal, and an original conveying device 3 is attached to the upper portion of the upper housing 2b. On the other hand, the main body housing 2a is provided with various mechanisms, which will be described later, for transferring an image to a sheet based on an electric signal of the read original image. A sheet post-processing device 20 is attached to the left side of the main body housing 2a. ing.

  In the present embodiment, the main body housing 2a includes a lower housing 2aa and a connection housing 2ab that is positioned along the right side and connected to the upper housing 2b. The lower housing 2aa is provided with a paper feeding unit 4 for the paper P, an image forming unit 6 for forming a toner image on the paper P, a fixing device 7 for fixing the toner image on the paper, and the like. The connection housing 2ab is provided with a paper discharge portion (discharge portion) 18 for conveying the fixed paper P and discharging it from the main body housing 20.

  In addition, on the left side of the connecting housing 2ab immediately below the upper housing 2b, an in-body discharge space 16 is formed that is largely open toward the left side and the front. In the in-body discharge space 16, the paper P discharged from the left side surface of the connecting housing 2 ab is received and stacked, and when the paper P is subjected to predetermined post-processing, it is conveyed to the paper post-processing device 20. An enabling relay unit 19 is provided.

  In the main body housing 2 a, the sheet feeding unit 4 disposed at the lower part, the sheet conveying unit 5 disposed on the side and above the sheet feeding unit 4, and the sheet feeding unit 4 are disposed above the sheet feeding unit 4. An image forming unit 6 and a fixing unit 7 disposed on the downstream side of the image forming unit 6 in the sheet conveying direction (the right side in FIG. 2) are provided.

  The paper feed unit 4 is provided with a plurality of paper feed cassettes 4a provided with separation feed means such as paper feed rollers on the downstream side in the paper transport direction. A bundle of sheets P placed in the sheet feeding cassette 4a is fed one by one from the uppermost sheet P to the sheet conveying section 5 by the rotation operation of the sheet feeding roller. The paper transport unit 5 transports the paper P fed from the paper feed unit 4 to the image forming unit 6 by each transport roller pair 5a.

  The image forming unit 6 and the fixing unit 7 are elongated in the width direction (front-rear direction, direction orthogonal to the paper surface of FIG. 1) orthogonal to the paper conveyance direction inside the apparatus main body 100. The image forming unit 6 and the fixing unit 7 are juxtaposed along the conveyance direction (from left to right) of the sheet P in the order of the image forming unit 6 and the fixing unit 7 from the left side in FIG. 1 in the upper part of the lower housing 2aa. Yes.

  The image forming unit 6 forms a predetermined toner image on the paper P by an electrophotographic process. The image forming unit 6 includes a photosensitive drum 9 that is an image carrier that is rotatably supported, and a charging device 11 that is disposed around the photosensitive drum 9 along the rotation direction, an exposure device 12, and the like. A developing device 13, a transfer device 14, a cleaning device 15, and a static elimination device (not shown) are provided. The fixing unit 7 heats and presses the sheet P on which the toner image has been transferred in the image forming unit 6 between a pair of fixing rollers 7a including a heating roller and a pressure roller, thereby forming an unfixed toner image. Fix on the paper P.

  An image reading unit 8 is provided in the upper housing 2b. The image reading unit 8 reads image information of a document. When placing the originals one by one by hand and causing the image reading unit 8 to read the originals, the original conveyance device 3 is opened and the originals are placed on the contact glass 8a provided on the upper surface of the upper housing 2b. When the originals are automatically supplied from the original bundle one by one and are read by the image reading unit 8, the original bundle is placed on the paper feed tray 3 a of the original conveying device 3 in a closed state. When the original bundle is placed on the paper feed tray 3a, the originals from the original bundle are automatically and sequentially sent onto the contact glass 8a one by one. In either case, the original positioned on the contact glass 8a is irradiated with light from an exposure lamp (not shown), and the reflected light is transmitted as image light to an optical system (not shown) such as a reflecting mirror and an imaging lens. To the photoelectric conversion unit (CCD).

  Hereinafter, a basic operation of the image forming apparatus 100 configured as described above will be described. First, the surface of the photosensitive drum 9 that rotates counterclockwise in FIG. 1 is uniformly charged by the charging device 11. Subsequently, based on the image information read by the image reading unit 8, a laser beam from the exposure device 12 (laser device or the like) is applied to the peripheral surface of the photosensitive drum 9, and thereby the surface of the photosensitive drum 9 is statically irradiated. An electrostatic latent image is formed. By supplying toner as a developer from the developing device 13 to the electrostatic latent image, a toner image is formed.

  Next, the paper P from the paper supply unit 4 passes through the paper transport path 5 and is transported toward the photosensitive drum 9 on which the toner image is formed at a predetermined timing. Then, the toner image on the surface of the photosensitive drum 9 is transferred onto the paper P by the transfer device 14 including a transfer roller or the like. The paper P on which the toner image is transferred is separated from the photosensitive drum 9 and conveyed toward the fixing unit 7. The paper P is heated and pressurized when passing through the fixing roller pair 7a to fix the toner image.

  After the transfer of the toner image to the paper P is completed, after the residual toner remaining on the outer peripheral surface is removed by the cleaning device 15, the residual charge is removed by a static eliminator (not shown). A static elimination process is performed. Thereafter, the charging device 11 charges the outer peripheral surface of the photosensitive drum 9 again, and image formation is performed in the same manner.

  The sheet P that has passed through the fixing unit 7 is conveyed in the connection housing 2ab along the sheet conveying path 5 as it is vertically upward. The upper part of the sheet conveyance path 5 branches into two upper and lower conveyance paths toward the left in the connection housing 2ab, and the conveyance direction of the sheet P is switched by a switching claw 17 arranged at the branching portion.

  A paper discharge portion 18 is provided in the connection housing 2ab. The paper discharge unit 18 includes an upper discharge roller pair 18a and a lower discharge roller pair 18b disposed immediately below the upper discharge roller pair 18a, and the paper P conveyed through the paper conveyance path 5 is a switching claw. 17 is guided to an upper conveyance path or a lower conveyance path.

  The paper P guided to the upper conveyance path by the switching claw 17 is discharged leftward from the upper discharge roller pair 18a. The paper P guided to the lower conveyance path by the switching claw 17 is discharged to the left by the lower discharge roller pair 18b. The switching claw 17 switches the guide direction by a control unit (not shown).

  The relay unit 19 is detachably attached to the bottom surface 16 a of the in-body discharge space 16. A detection sensor (not shown) for detecting the attachment of the relay unit 19 is provided in the in-body discharge space 16. The detection sensor is configured by a PI sensor or the like, and transmits a detection result to the control unit.

  In addition, an inclined surface that is inclined upward toward the downstream side in the sheet discharge direction (left side in FIG. 1) is formed on the bottom surface 16a. When the relay unit 19 is separated from the in-body discharge space 16, the bottom surface 16a is used as a sheet discharge tray. In this case, the detection sensor detects that the relay unit 19 is not mounted, and when the detection result is transmitted to the control unit, the switching claw 17 guides the paper P to the upper discharge roller pair 18a. The paper P discharged from the upper discharge roller pair 18a is discharged onto the bottom surface 16a.

  On the other hand, when the detection sensor detects that the relay unit 19 is installed in the in-body discharge space 16 and the detection result is transmitted to the control unit, the switching claw 17 guides the paper P to the lower discharge roller pair 18b. To do. Then, the paper P discharged from the lower discharge roller pair 18 b is carried into the relay unit 19. The paper P carried into the relay unit 19 passes through the relay unit 19 and is carried into the paper post-processing device 20.

  The detection result can be displayed on an operation unit (not shown), and the user can switch the guidance direction of the paper P on the operation panel. Further, the upper surface portion of the relay unit 19 also has a function as a paper discharge tray on which the paper P discharged from the upper discharge roller pair 18a is placed.

  Inside the sheet post-processing device 20, a punch hole forming device 21 that forms punch holes for the loaded paper P, a processing tray 30 for stacking a plurality of loaded paper P, and a processing tray 30 A stapler 40 is provided for binding the bundle of sheets stacked on the printer. A discharge tray 50 that can be raised and lowered to a position suitable for discharging the paper P is provided on the side surface of the paper post-processing device 20.

  The punch hole forming device 21 is disposed on the upper portion of the paper post-processing device 20 and forms a plurality of punch holes along one side edge (the front side or the rear side) parallel to the transport direction of the paper P. . At a substantially central portion in the direction (perpendicular to the paper surface in FIG. 1) upstream of the punch hole forming device 21 and perpendicular to the paper transport direction, a pair of paper carry-in rollers in the relay unit 19 is placed in the paper post-processing device 20. A carry-in detection sensor (not shown) for detecting the leading edge of the paper P to be carried in is arranged.

  The control unit (not shown) controls the drive of the pair of paper carry-in rollers in the relay unit 19 based on the detection timing of the leading edge of the paper P by the carry-in detection sensor, so that the paper conveyed to the punch hole forming device 21 The punch hole forming position in the conveyance direction of P is adjusted. Specifically, a conveyance direction pulse adjustment value for adding or subtracting a reference conveyance pulse value from the detection of the leading or trailing edge of the paper P by the carry-in detection sensor to the stop of the paper carry-in roller pair is set.

  2 and 3 are partial cross-sectional views around the processing tray 30 in the sheet post-processing apparatus 20. A first discharge roller pair 27 is disposed on the downstream side of the punch hole forming device 21 (see FIG. 1) with respect to the paper transport direction. An actuator type paper detection sensor 28 that detects the passage of the paper P is disposed upstream of the first discharge roller pair 27.

  Further, below the first discharge roller pair 27, a processing tray 30 on which a predetermined number of sheets P conveyed by the first discharge roller pair 27 are aligned and stacked, and a bundle of sheets P stacked on the processing tray 30 ( A stapler 40 (see FIG. 1) that performs a binding process is provided on the sheet bundle.

  A second discharge roller pair 29 that discharges the sheet bundle from the processing tray 30 to the discharge tray 50 is disposed on the downstream side of the processing tray 30 with respect to the sheet conveyance direction. The second discharge roller pair 29 includes a rubber discharge roller 29a that can be rotated forward and backward by a drive motor (not shown), and a resin discharge roller 29b that rotates following the discharge roller 29a. . The discharge roller 29a is supported by a roller holder 31 that can swing up and down about the rotation shaft 31a.

  At the upper side of the processing tray 30 and downstream of the first discharge roller pair 27 (left side in FIG. 2), the paper P carried by the first discharge roller pair 27 is struck in the direction of the processing tray 30 and along the tray surface. A hitting member 33 is provided for the purpose. The processing tray 30 is provided so as to be inclined downward toward the rear end side of the stacked paper P (the downstream side with respect to the drawing direction of the paper into the processing tray 30 and the right side in FIG. 2). By the reverse rotation of the roller pair 29, the paper P is drawn onto the processing tray 30 from the rear end side, and the rear end of the paper P comes into contact with the abutting portion 30a. As a result, the sheets are stacked on the processing tray 30 with the rear ends thereof aligned. Further, the processing tray 30 is provided with a pair of side edge alignment cursors 60 for aligning the sheet bundle loaded on the processing tray 30 in the width direction (direction perpendicular to the paper surface of FIG. 2).

  The stapler 40 can be moved in the paper width direction perpendicular to the transport direction by a moving mechanism (not shown), and moves to a predetermined position along the lower end of the processing tray 30 according to the content of the binding process.

  Next, the operation of the sheet post-processing apparatus 20 will be described. When a sheet P (indicated by a broken line in FIGS. 2 and 3) on which image forming processing has been performed by the image forming apparatus 100 is carried in, if punch hole formation is instructed, the sheet P is conveyed by the punch hole forming apparatus 21. Punch holes are formed at predetermined positions (for example, two locations along the side edge on the front side of the apparatus) of the sheet P to be printed. If punch hole formation is not instructed, the paper P passes through the punch hole forming device 21 as it is.

  Then, the paper P is conveyed further downstream by the first discharge roller pair 27. At this time, as shown in FIG. 2, the roller holder 31 swings upward, and the discharge roller 29a is disposed at a position (retracted position) away from the discharge roller 29b. Therefore, the paper P conveyed by the first discharge roller pair 27 protrudes to the discharge tray 50 through the gap between the discharge roller 29a and the discharge roller 29b.

  At the timing when the rear end of the sheet P passes through the first discharge roller pair 27, the roller holder 31 is swung downward and the discharge roller 29a is disposed at a position (contact position) where the discharge roller 29a contacts the discharge roller 29b. Thereafter, the tapping member 33 is driven to cause the paper P to follow the processing tray 30. In this state, by rotating the discharge roller 29a in the reverse direction (counterclockwise direction in FIG. 3), the paper P is drawn along the processing tray 30, and the trailing edge is aligned by the abutting portion 30a. The abutting portion 30a is not continuously formed over the entire area in the paper width direction, but is partially formed with a notch. At this time, the upper part of the paper P is nipped by the second discharge roller pair 29, and the front end of the paper P protrudes from the second discharge roller pair 29 onto the discharge tray 50. When the paper P is pulled along the processing tray 30, the paper P is nipped in a state where the discharge roller 29a is pressed against the discharge roller 29b only by its own weight so that the paper P is not pulled more than necessary. To do.

  When the acceptance of the paper P for one bundle is completed, the stapler 40 is moved to the notch position of the abutting portion 30a to insert the rear end of the paper bundle into the staple portion 40a, and the staple portion 40a binds the paper bundle. Processing is performed. After the sheet bundle is bound by the staple unit 40a, the sheet bundle is conveyed upward along the processing tray 30 by rotating the second discharge roller pair 29 in the normal direction (in the direction of the arrow in FIG. 3), and the discharge tray 50 Discharged to the top. When the sheet bundle is discharged to the discharge tray 50, not only the weight of the roller holder 31 but also the roller holder 31 is urged downward by a biasing member such as a spring so that the discharge roller 29a is pressed against the discharge roller 29b. As a result, the sheet bundle is nipped with a stronger force than when the sheet P is pulled in, so that the sheet bundle can be reliably discharged to the discharge tray 50.

  When the shift discharge is instructed, the roller holder 31 is first moved to the retreat position when the second discharge roller pair 29 is driven to discharge the sheet bundle to the discharge tray 50. After that, the side edge alignment cursor 60 is arranged at a position (shift position) shifted by a predetermined amount from the position where the paper P is received (reference position) or from the reference position in a direction orthogonal to the discharge direction (paper width direction). Then, the roller holder 31 is moved to the contact position to discharge the paper. As a result, the sheet bundle is alternately discharged to a reference discharge position on the discharge tray 50 and a shift discharge position shifted by a predetermined amount from the reference discharge position in a direction orthogonal to the discharge direction (paper width direction). When being discharged onto the discharge tray 50 (see FIG. 2), they are alternately stacked in the paper width direction and sorted.

  In the paper post-processing apparatus 20 according to the present embodiment, the discharge roller 29b constituting the second discharge roller pair 29 is rotated only in the forward direction (counterclockwise direction in FIGS. 2 and 3) in which the paper P is discharged to the discharge tray 50. It is possible.

  With this configuration, as shown in FIG. 4, when the sheet P2 is pulled into the processing tray 30 using the second discharge roller pair 29, only the discharge roller 29a is reversely rotated while the rotation of the discharge roller 29b is stopped. Let As a result, the pull-in force acts only on the newly loaded paper P2, and does not act on the paper bundle P1 that is already abutted against the abutting portion 30a of the processing tray 30 and aligned. Accordingly, there is no possibility that the sheet bundle P1 is drawn and bent together with the sheet P2, and the deterioration of the consistency of the sheet bundle on the processing tray 30 can be effectively prevented.

  As a method for enabling the discharge roller 29b only to rotate forward, for example, a method of incorporating a one-way mechanism such as a one-way gear or a one-way clutch that can rotate only in one direction on the rotation shaft of the discharge roller 29b can be cited.

  Further, by making the roller holder 31 that supports the discharge roller 29a swingable, the arrangement of the discharge roller 29a can be separated from the discharge roller 29b (retracted position) and at a position in contact with the discharge roller 29b (current position). It is possible to easily switch to the contact position.

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning of this invention. For example, in the above embodiment, the configuration in which the image forming apparatus 100 and the paper post-processing apparatus 20 are directly connected has been described as an example. However, a slip sheet is inserted between the image forming apparatus 100 and the paper post-processing apparatus 20. The present invention can also be applied to a configuration in which an insert device is mounted.

  The present invention is applicable to a sheet post-processing apparatus that aligns and stacks sheets on a processing tray using a discharge roller pair. By utilizing the present invention, a sheet post-processing apparatus capable of preventing misalignment of a sheet bundle when aligning the sheet bundle by pulling a sheet onto a processing tray by a pair of discharge rollers and an image forming system including the same are provided. be able to.

Claims (6)

A processing tray for receiving and stacking a predetermined number of sheets;
A discharge tray disposed on the downstream side of the processing tray in the sheet conveying direction and for discharging sheets stacked on the processing tray;
A discharge roller that contacts the uppermost surface of the sheets stacked on the processing tray; and a discharge roller that contacts the lowermost surface of the sheets stacked on the processing tray and is rotatable only in the direction of discharging the sheets to the discharge tray. A pair of discharge rollers composed of
In a sheet post-processing apparatus comprising:
The sheet is discharged from the processing tray to the discharge tray by rotating the discharge roller pair forward, and the sheet is transferred to the processing tray by reversely rotating the discharge roller in a state where the rotation of the discharge roller is stopped. A sheet post-processing apparatus that performs drawing.   A swingable roller holder that rotatably supports the discharge roller is provided. The swing of the roller holder causes the discharge roller to come in contact with the discharge roller and a retreat position that is separated from the discharge roller. The sheet post-processing apparatus according to claim 1, wherein the sheet post-processing apparatus is selectively disposed at a contact position. An urging member for urging the roller holder downward;
When the sheet is drawn into the processing tray, the discharge roller is arranged at the contact position only by the weight of the roller holder,
When discharging the sheet to the discharge tray, in addition to the weight of the roller holder, the roller holder is urged downward by the urging member, and the discharge roller is arranged at the contact position. The sheet post-processing apparatus according to claim 2.   The sheet post-processing apparatus according to claim 1, wherein the discharge roller is rotated forward by following the discharge roller, and a one-way mechanism for restricting reverse rotation of the discharge roller is provided.   The sheet post-processing apparatus according to claim 1, wherein the processing tray is provided so as to be inclined downward toward a downstream side with respect to a drawing direction of the sheet into the processing tray. The sheet post-processing apparatus according to claim 1;
An image forming apparatus connected to the sheet post-processing apparatus to form an image on the sheet and to convey the sheet on which the image is formed to the sheet post-processing apparatus;
An image forming system.

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