JP2019043695A - Sheet post-processing device and image formation system - Google Patents

Abstract

To provide a sheet post-processing device capable of properly detecting a sheet remaining in a processing tray, and of suppressing deterioration of remaining thereof with no occurrence of conveyance resistance and erroneous detection.SOLUTION: A sheet post-processing device comprises a processing tray, a processing unit, a discharge port, a pair of discharge rollers, a discharge tray, a conveyance part, a pull-in part, a detection part, and a control part. The pull-in part is supported to be opposed to the processing tray in a freely swingable manner, is contactable and separable from an upper side to a sheet loaded on the processing tray, and moves the sheet conveyed to the processing tray toward an upstream end in a conveyance direction. The detection part detects an upward displacement beyond a predetermined position of the pull-in part which comes into contact with the sheet loaded on the processing tray. The control part prohibits conveying the next sheet to the processing tray, when acquiring a detection signal relating to the upward displacement of the pull-in part from the detection part after moving the sheet toward the upstream end in the conveyance direction of the processing tray using the pull-in part.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a sheet post-processing device of an image forming apparatus, and an image forming system provided with the sheet post-processing device.

  A sheet post-processing apparatus may be connected to an image forming apparatus in order to post-process and orderly convey a sheet such as paper after image formation using an image forming apparatus such as a copying machine. The sheet post-processing apparatus is used, for example, when forming a plurality of copies of the same document in one job and forming an image, the sheet post-processing apparatus is to be bundled and discharged for each set. In addition, a binding process of binding a sheet bundle using, for example, a metal staple, or a punch hole forming (perforating) process of punching punch holes may be performed on the bundle of sheet bundles.

  Such sheet post-processing apparatuses include a processing tray on which sheets after image formation are stacked, and a discharge tray disposed on the downstream side of the processing tray in the sheet conveying direction. Post-processing for bundling a plurality of sheets and performing binding processing is performed on the processing tray. It is important to detect the retention of the sheet in the processing tray due to a jam or the like in order to facilitate the post-processing on the sheet. For example, Patent Document 1 discloses a conventional technique relating to detection of sheets stacked on a tray.

  The conventional sheet processing apparatus disclosed in Patent Document 1 includes a sheet discharge tray on which sheets are stacked, a fully-displaceable full-load detection flag (sheet pressing member) contacting the upper surface of the sheets stacked on the sheet discharge tray, and And a photo interrupter (position detection means) for detecting the displacement of the full load detection flag. The sheet processing apparatus can detect the full load of sheets on the sheet discharge tray based on the displacement of the full load detection flag.

Unexamined-Japanese-Patent No. 2006-306536

  However, in the conventional sheet processing apparatus of Patent Document 1, the sheet moving toward the sheet discharge tray moves while being in contact with the full load detection flag. In addition, although it is conceivable to dispose a reflection type optical sensor to detect the presence or absence of the sheet on the processing tray of the sheet post-processing apparatus, a large number of movable parts exist around the processing tray. There was a concern that false detection would occur that would detect these moving parts.

  The present invention has been made in view of the above-described point, and it is possible to properly detect a sheet stagnating in a processing tray without causing conveyance resistance or false detection, and to suppress deterioration of the stagnation. It is an object of the present invention to provide a processing device and an image forming system.

  In order to solve the above problems, the sheet post-processing apparatus of the present invention includes a processing tray, a processing unit, a discharge port, a pair of discharge rollers, a discharge tray, a conveyance unit, a pull-in unit, a detection unit, and a control unit. The processing tray is loaded with sheets. The processing unit post-processes the sheets stacked on the processing tray. The discharge port is disposed downstream of the processing tray in the sheet conveyance direction. A discharge roller pair is disposed at the discharge port. The discharge tray is loaded with sheets discharged from the discharge port by forward rotation of the discharge roller pair. The transport unit transports the sheet stacked on the processing tray toward the discharge port. The pull-in unit is supported so as to be movable in opposition to the processing tray, and can contact and separate from above the sheet stacked on the processing tray, and the sheet conveyed to the processing tray by reverse rotation of the discharge roller pair Are moved toward the upstream end of the processing tray in the sheet conveying direction. The detection unit detects an upward displacement beyond the predetermined position of the pull-in unit in contact with the sheet stacked on the processing tray. The control unit controls the operation of the discharge roller pair, the conveyance unit, and the drawing unit. Further, after the control unit moves the sheet toward the sheet conveyance direction upstream end of the processing tray using the pull-in unit, the processing is performed when a detection signal related to the upward displacement of the pull-in unit is acquired from the detection unit Prohibit the next sheet transport to the tray.

  According to the configuration of the present invention, a pull-in unit for moving the sheet conveyed to the processing tray toward the upstream end of the processing tray in the sheet conveyance direction can be used to detect a sheet jam in the processing tray. That is, there is no need to separately provide a member in contact with the sheet in order to detect a jam. Then, it is possible to detect a jam and immediately prohibit the transport of the next sheet to the processing tray. Therefore, it is possible to appropriately detect the sheet stagnating in the processing tray without causing the conveyance resistance and the erroneous detection, and to suppress the deterioration of the stagnation.

FIG. 1 is a cross-sectional view showing a schematic configuration of an image forming system according to an embodiment of the present invention. It is a sectional view showing the composition of the sheet post-processing device concerning the embodiment of the present invention. It is a front view which shows the drawing-in part periphery of the sheet post-processing apparatus concerning the embodiment of the present invention, and is a figure showing the state where the drawing-in part was separated from the sheet on a processing tray. It is a front view which shows the drawing-in part periphery of the sheet post-processing apparatus which concerns on embodiment of this invention, Comprising: It is a figure which shows the state which made the drawing-in part contact the sheet on a processing tray. It is a front view which shows the drawing-in part periphery of the sheet post-processing apparatus which concerns on embodiment of this invention, Comprising: It is a figure which shows the state which jammed in the sheet on a processing tray.

  Hereinafter, an embodiment of the present invention will be described based on the drawings. The present invention is not limited to the following contents.

  First, a schematic configuration of an image forming system according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is an example of a cross-sectional view showing a schematic configuration of an image forming system. The image forming system S includes an image forming apparatus 101 and a sheet post-processing apparatus 1.

  The image forming apparatus 101 is, for example, a so-called multifunction machine provided with functions such as printing (printing), scanning (image reading), and facsimile transmission. As illustrated in FIG. 1, the image forming apparatus 101 includes a sheet supply unit 102, a sheet conveyance unit 103, an image forming unit 104, a transfer unit 105, a fixing unit 106, a sheet discharge unit 107, and a main control unit 108.

  The sheet supply unit 102 accommodates a plurality of sheets P, and separates and feeds the sheets P one by one at the time of printing. The sheet conveyance unit 103 conveys the sheet P fed from the sheet supply unit 102 to the transfer unit 105 and the fixing unit 106, and further conveys the sheet P after fixing to the sheet discharge unit 107.

  The image forming unit 104 includes a photosensitive drum 104 a which is an image carrier rotatably supported counterclockwise in FIG. 1. The image forming unit 104 forms a toner image on the surface of the photosensitive drum 104a. The transfer unit 105 transfers the toner image on the surface of the photosensitive drum 104 a to the sheet P. The fixing unit 106 fixes the toner image on the sheet P by heating and pressurizing the sheet P on which the toner image has been transferred.

  The sheet discharge unit 107 has a switching claw 107a. The sheet discharge unit 107 distributes the sheet P after fixing to the in-body discharge unit 111 or the relay unit 112 using the switching claw 107 a. The in-body discharge unit 111 has an opening in the front, and the sheet P after printing is taken out from the front side. The relay unit 112 is connected to the sheet post-processing apparatus 1 at the downstream end in the sheet conveyance direction. The sheet P sent to the relay unit 112 passes through the inside of the relay unit 112 and is conveyed to the sheet post-processing apparatus 1.

  The main body control unit 108 includes a CPU (not shown), an image processing unit, and other electronic circuits and electronic components. The main body control unit 108 controls each component of the image forming apparatus 101 based on a program and data stored and input in a storage unit (not shown) using a CPU as a central processing unit and an image processing unit. The image forming operation and the printing operation are realized. The sheet supply unit 102, the sheet conveyance unit 103, the image forming unit 104, the transfer unit 105, the fixing unit 106, the sheet discharge unit 107, and the like individually receive instructions from the main body control unit 108, and the constituent elements interlock in cooperation Implement image formation on P.

  The sheet post-processing apparatus 1 is detachably connected to the side surface of the image forming apparatus 101. The sheet post-processing apparatus 1 can be connected similarly to, for example, a laser printer, an ink jet printer, etc. in addition to the multi-function device. As shown in FIG. 1, the sheet post-processing apparatus 1 includes a sheet inlet 2, a sheet discharge path 3, a processing tray 4, a discharge tray 5, a punch 6, a binding unit (processing unit) 7, and a post-processing control unit 8. .

  The sheet loading port 2 is provided on the side facing the relay unit 112 of the image forming apparatus 101 and opens. The sheet P having passed through the relay unit 112 is conveyed into the sheet post-processing apparatus 1 through the sheet inlet 2.

  The sheet discharge path 3 extends from the sheet inlet 2 to the upper side of the processing tray 4. The processing tray 4 is disposed below the downstream portion of the sheet discharge path 3. The plurality of sheets P transported to the processing tray 4 through the sheet discharge path 3 are stacked on the processing tray 4 and subjected to post-processing. The discharge tray 5 is disposed downstream of the processing tray 4 in the sheet conveying direction. When the post-processing by the binding unit 7 is not performed, the sheet P is conveyed to the discharge tray 5 without being stacked on the processing tray 4.

  The processing tray 4 and the discharge tray 5 have an inclination which ascends as the sheet placement surface goes downstream in the sheet conveyance direction. The sheet P for which the post-processing is completed in the processing tray 4 is discharged to the discharge tray 5 and taken out.

  The punch unit 6 is disposed at an intermediate portion from the sheet inlet 2 which is the upstream end of the sheet discharge path 3 to the downstream end. The sheet post-processing apparatus 1 can perform punching processing on the sheet P conveyed in the sheet discharge path 3 using the punch unit 6 to form punch holes.

  The binding unit 7 is disposed upstream of the processing tray 4 in the sheet conveying direction. The sheet post-processing apparatus 1 can perform a binding process (post-processing) on the bundle of sheets P stacked on the processing tray 4 using the binding unit 7 and can bind the sheet bundle.

  The post-processing control unit 8 includes a CPU (not shown) and other electronic circuits and electronic components. The post-processing control unit 8 is communicably connected to the main control unit 108. The post-processing control unit 8 receives a command from the main body control unit 108, uses a CPU that is a central processing unit, and stores each of the components in the sheet post-processing device 1 based on programs and data stored and input in a storage unit (not shown). The elements are controlled to realize a series of post-processing operations. The sheet discharge path 3, the processing tray 4, the punch unit 6, the binding unit 7 and the like individually receive instructions from the post-processing control unit 8, and the constituent elements interlock to carry out post-processing on the sheet P.

  Subsequently, the configuration of the sheet post-processing apparatus 1 will be described with reference to FIG. FIG. 2 is an example of a cross-sectional view showing the configuration of the sheet post-processing apparatus 1.

  In addition to the sheet discharge path 3, the processing tray 4, and the discharge tray 5 shown in FIG. 2, the sheet post-processing apparatus 1 includes the intermediate roller pair 9, the discharge port 10, the discharge roller pair 11, the transport unit 12, the pull-in unit 20 and the detection A unit 30 is provided.

  The intermediate roller pair 9 is disposed downstream of the punch 6 (see FIG. 1) in the sheet discharge path 3 in the sheet conveyance direction. The rotation axis of the intermediate roller pair 9 is orthogonal to the sheet conveyance direction and extends along the sheet width direction (direction perpendicular to the paper surface of FIG. 2). A plurality of intermediate roller pairs 9 are provided at intervals along the sheet width direction. The intermediate roller pair 9 conveys the sheet P conveyed in the sheet discharge path 3 further toward the discharge port 10 on the downstream side. The processing tray 4 is positioned immediately below the downstream side of the intermediate roller pair 9 in the sheet conveyance direction.

  The discharge port 10 is disposed downstream of the intermediate roller pair 9 in the sheet conveyance direction and downstream of the processing tray 4 in the sheet conveyance direction. The sheet P for which the post-processing is completed in the processing tray 4 is discharged toward the discharge tray 5 through the discharge port 10.

  The discharge roller pair 11 is disposed at the discharge port 10. The rotation axis of the discharge roller pair 11 is orthogonal to the sheet conveyance direction and extends along the sheet width direction (direction perpendicular to the paper surface of FIG. 2). The discharge roller pair 11 includes an upper discharge roller 11a and a lower discharge roller 11b. The upper discharge roller 11a is connected to a drive motor (not shown), and can perform forward rotation for sending the sheet P to the discharge tray 5 and reverse rotation for sending the sheet P to the processing tray 4 side. The lower discharge roller 11b contacts the upper discharge roller 11a and is driven to rotate. The post-processing control unit 8 controls the rotation of the upper discharge roller 11 a.

  The upper discharge roller 11 a is supported by the arm 13. The arm 13 extends along the sheet conveyance direction, holds the upper discharge roller 11a at one end on the downstream end side in the sheet conveyance direction, and can swing around the rotation shaft 13a extending along the sheet width direction at one end on the upstream end side Supported by The arm 13 is connected to a drive motor (not shown), and one end of the arm 13 supporting the upper discharge roller 11a is pivoted around the rotation shaft 13a. The upper discharge roller 11 a contacts and separates from the lower discharge roller 11 b by the swinging of the arm 13. As shown in FIG. 2, when the upper discharge roller 11 a contacts the lower discharge roller 11 b, the conveyance nip of the sheet P is formed at the contact portion with each other. The post-processing control unit 8 controls the swing of the arm 13.

  The sheet P discharged from the discharge port 10 is stacked on the discharge tray 5 by the forward rotation of the discharge roller pair 11. When the discharge roller pair 11 rotates in the reverse direction while the sheet P is held by the conveyance nip of the discharge roller pair 11 and the upstream end of the sheet P in the conveyance direction is separated from the conveyance nip of the intermediate roller pair 9, the sheet P Is conveyed to the processing tray 4.

  The operation relating to the processing tray 4 is, for example, as follows. The sheet P is conveyed to the processing tray 4 by the intermediate roller pair 9 in a state where the discharge roller pair 11 is separated. When the upstream end of the sheet P in the transport direction reaches the processing tray 4, the discharge roller pair 11 is closed. The discharge roller pair 11 is reversely rotated to move the sheet P to the upstream side in the conveyance direction. At this time, the pull-in unit 20 is swung to bring a movable roller 23, which will be described later, into contact with the upper surface of the sheet P. Further, the movable roller 23 is rotated to move the sheet P to the upstream side in the transport direction, and the sheet P is positioned at the post-processing position by the binding unit 7. Then, the pull-in unit 20 is retracted upward. The same process is repeated for the second and subsequent sheets, and the sheet bundle is aligned with the post-processing position by the binding section 7. When a predetermined number of sheet bundles are formed, post-processing is performed. Subsequently, the sheet bundle is pushed up to a predetermined position by the conveyance unit 12. Then, the discharge roller pair 11 is closed to sandwich the sheet bundle, and the discharge roller pair 11 is rotated forward to convey the sheet bundle to the discharge tray 5.

  In addition, the processing tray 4 includes the upstream end contact member 4a. The upstream end contact member 4 a is disposed upstream of the processing tray 4 in the sheet conveying direction. The upstream end contact member 4a is brought into contact with the upstream end of the conveyance direction of the sheet P conveyed from the discharge port 10 to the processing tray 4 by the reverse rotation of the ejection roller pair 11, and the position of the upstream end of the plurality of sheets P in the conveyance direction Align.

  The transport unit 12 is provided on the processing tray 4. The transport unit 12 includes a transport member 12a. The conveying members 12a are provided in the same configuration in the sheet width direction. The conveying member 12 a circulates counterclockwise along an oval shape represented by an arrow R in FIG. 2 by a driving mechanism (not shown) of the conveying unit 12.

  The conveyance member 12a appears above the placement surface of the sheet P in the vicinity of the arrangement position of the upstream end contact member 4a and the upstream portion of the processing tray 4 in the sheet conveyance direction. Then, the conveyance member 12 a moves toward the downstream side in parallel with the placement surface of the sheet P of the processing tray 4, thereby conveying the sheet P stacked on the processing tray 4 toward the discharge port 10. When the conveyance member 12 a reaches the downstream portion of the processing tray 4 in the sheet conveyance direction and the vicinity of the arrangement position of the discharge port 10, the conveyance member 12 a is hidden below the mounting surface of the sheet P. Then, below the placement surface of the sheet P, the transport member 12a moves in parallel with the placement surface of the sheet P of the processing tray 4 toward the upstream side. The operation of the transport member 12 a is controlled by the post-processing control unit 8.

  The pull-in unit 20 and the detection unit 30 are disposed above the upstream portion of the processing tray 4 in the sheet conveyance direction. The pull-in unit 20 is rotatably supported opposite to the processing tray 4. The operation of the pull-in unit 20 is controlled by the post-processing control unit 8. Further, the detection signal of the detection unit 30 is transmitted to the post-processing control unit 8.

  Subsequently, the detailed configurations of the pull-in unit 20 and the detection unit 30 will be described with reference to FIGS. 3 to 5 in addition to FIG. 2. FIG. 3 is a front view showing the vicinity of the drawing-in unit 20 and is a view showing a state where the drawing-in unit 20 is separated from the sheet P on the processing tray 4. FIG. 4 is a front view showing the periphery of the drawing-in unit 20 and a state in which the drawing-in unit 20 is in contact with the sheet P on the processing tray 4. FIG. 5 is a front view showing the periphery of the pull-in unit 20 and is a view showing a state in which the sheet P on the processing tray 4 is jammed.

  The pull-in unit 20 includes a rocking shaft 21, a rocking member 22, a movable roller 23 and a detected portion 24 shown in FIGS. 2 and 3.

  The rocking shaft 21 is provided such that the axis coincides with the rotation axis of the lower intermediate roller 9 b of the intermediate roller pair 9. The rocking shaft 21 may be shared as a rotating shaft of the lower intermediate roller 9b. The swing shaft 21 extends in the sheet width direction. The rocking shaft 21 rotatably supports the rocking member 22.

  The rocking shaft 21 is provided with two projecting portions 21 a projecting radially outward at a portion supporting the rocking member 22. The two protrusions 21 a are disposed at symmetrical positions with respect to the central axis of the swing shaft 21. That is, the two protrusions 21 a are disposed on opposite sides of each other with the central axis of the swing shaft 21 separated. For example, the protrusion 21 a is formed of a pin that penetrates the swinging shaft 21.

  The swinging member 22 is constituted by a frame including a pair of side plates 22a extending in the sheet conveying direction and a connecting plate (not shown) connecting them. One end side of the rocking member 22 in the longitudinal direction is rotatably supported centering on the rocking shaft 21, and the other end side is rocked and displaced. The swinging member 22 is disposed upstream of the swinging shaft 21 in the sheet conveying direction of the processing tray 4, that is, to the right of the swinging shaft 21 in FIGS. 2 and 3.

  The swinging member 22 includes a bearing 22b having a substantially circular cross section provided at one end of the side plate 22a on the supported side. The rocking shaft 21 is inserted into the bearing 22 b.

  The bearing 22b includes an axial hole 22c and an overhang 22d. The shaft hole 22 c penetrates the side plate 22 a in the sheet width direction to support the swing shaft 21. The overhanging portion 22 d expands the hole radially outward from the inner peripheral surface of the shaft hole 22 c. The overhanging portions 22 d are provided at two locations of the bearing 22 b corresponding to the projecting portions 21 a of the swing shaft 21. The two overhanging portions 22 d are disposed at symmetrical positions with respect to the central axis of the swing shaft 21. That is, the two overhanging portions 22 d are disposed on opposite sides of each other with the central axis of the rocking shaft 21 separated. The protrusion 21a is inserted into each of the two overhanging portions 22d.

  The overhanging portion 22 d has a fan-shaped gap 22 e as viewed from the front, in which the projecting portion 21 a can be relatively displaced in a predetermined region in the circumferential direction. The fan-shaped gap 22 e of the gap 22 e extends along the direction intersecting the swing axis 21.

  The movable roller 23 is attached to one end side of the rocking member 22 opposite to the side supported by the rocking shaft 21. The movable roller 23 is attached to the swinging member 22 so as to be rotatable about a shaft portion 23a extending in the sheet width direction. The movable roller 23 is rotated about a rotation shaft 23 a by a drive motor (not shown). The movable roller 23 approaches the processing tray 4 by the swinging of the swinging member 22, and the circumferential surface of the movable roller 23 contacts the sheet P stacked on the processing tray 4 from above. Thus, the pull-in unit 20 moves the sheet P conveyed to the processing tray 4 toward the upstream end of the processing tray 4 in the sheet conveyance direction. The post-processing control unit 8 controls the rotation of the movable roller 23.

  Here, the swing shaft 21 is rotated about its axis by a drive motor (not shown) different from the drive motor of the movable roller 23. Then, one end side of the rocking member 22 on which the movable roller 23 is provided is rocked. As a result, the movable roller 23 of the pull-in unit 20 can contact and separate from above the sheet P stacked on the processing tray 4. The post-processing control unit 8 controls the rotation of the rocking shaft 21.

  For example, the rocking shaft 21 is rotated by a stepping motor. The movable roller 23 provided at one end of the swinging member 22 on the swinging side moves to a predetermined position (a predetermined height relative to the upper surface of the processing tray 4) in accordance with the number of sheets P stacked. At this time, a predetermined number of pulses are sent to the stepping motor, and position control is performed. The movable roller 23 can move downward toward the sheet P by the action of gravity with respect to the swinging member 22 stopped at the predetermined position in the range of the area of the gap 22e of the bearing 22b. As a result, the movable roller 23 presses the sheet P to make contact.

  The detected portion 24 is provided near one end on the swinging side of the swinging member 22. The to-be-detected part 24 is a part of side plate 22a itself which is a flame | frame which comprises the rocking member 22. As shown in FIG. The detection target portion 24 may be configured as a separate member for the rocking member 22 and attached to the rocking member 22. The detection unit 24 is used by the detection unit 30 to detect the displacement of the swinging member 22.

  The detection unit 30 is provided on the swing path of one end of the swing member 22 on the swing side. The detection unit 30 is disposed above the processing tray 4 so as to be separated from the processing tray 4 at a predetermined height. The detection unit 30 is configured of, for example, a transmission type light sensor such as a photo interrupter having a light emission unit and a light reception unit (not shown). The detection unit 30 is disposed at a position where the detection target 24 passes through the optical path when the swing member 22 swings. The detection unit 30 detects an upward displacement of the pull-in unit 20 in contact with the sheets P stacked on the processing tray 4 beyond a predetermined position.

  Next, the operation of the lead-in unit 20 will be described with reference to FIGS.

  When the movable roller 23 is separated from the sheet P stacked on the processing tray 4, the swing shaft 21 is rotated counterclockwise to a predetermined angle as shown in FIG. 3. Since the swinging member 22 is disposed upstream of the swinging shaft 21 in the sheet conveying direction of the processing tray 4, the protrusion 21 a of the swinging shaft 21 is counter-clockwise due to the action of gravity on the swinging member 22. It contacts the inner surface of the overhang 22d located on the direction side. Thereby, the swinging member 22 rotates counterclockwise around the swinging shaft 21 to a predetermined angle. Then, the movable roller 23 separates from the processing tray 4 and is maintained at a predetermined height above the processing tray 4.

  At this time, the detected portion 24 of the swinging member 22 does not shield the light path of the detecting portion 30. In addition, even if the detected portion 24 shields the light path of the detection unit 30, the post-processing control unit 8 does not use the detection signal of the detection unit 30 at this stage.

  Subsequently, when bringing the sheet P stacked on the processing tray 4 into contact with the movable roller 23, as shown in FIG. 4, the swing shaft 21 is rotated clockwise to a predetermined angle. As a result, the swinging member 22 rotates clockwise about the swinging shaft 21 by the action of gravity on the swinging member 22. Then, the movable roller 23 contacts the sheet P stacked on the processing tray 4 from above.

  Here, when a drive motor (not shown) connected to the movable roller 23 is rotationally driven, the sheet P transported to the processing tray 4 is directed toward the upstream end of the processing tray 4 in the sheet transport direction, ie, the upstream end contact member 4a. It can be moved.

  The overhanging portion 22 d has a gap 22 e in which the projecting portion 21 a can be relatively displaced in a predetermined area in the circumferential direction. Therefore, when the movable roller 23 contacts the sheet P stacked on the processing tray 4 from above, one end on the swinging side of the swinging member 22 counterclockwise in the range of the gap 22e. It can be rotationally displaced.

  For this reason, as shown in FIG. 5, when a jam occurs on the sheet P stacked on the processing tray 4, one end on the swinging side of the swinging member 22 is rotationally displaced counterclockwise upward. When a jam occurs on the sheet P stacked on the processing tray 4, the swinging member 22 is displaced to the upper side beyond the predetermined position. The displacement of the swinging member 22 is detected by the detection unit 30 as the detection unit 24 passes through the optical path of the detection unit 30.

  Then, the post-processing control unit 8 moves the sheet P toward the upstream end of the processing tray 4 in the sheet conveying direction using the pull-in unit 20, and then detects a detection signal related to the upward displacement of the pull-in unit 20. When the sheet P is acquired from T <b> 30, the conveyance of the next sheet P to the processing tray 4 is prohibited.

  According to this configuration, the pull-in unit 20 for moving the sheet P conveyed to the processing tray 4 toward the upstream end of the processing tray 4 in the sheet conveyance direction is used to detect the jam of the sheet P in the processing tray 4 Can. That is, there is no need to separately provide a member in contact with the sheet P in order to detect a jam. Then, it is possible to detect a jam and immediately prohibit the conveyance of the next sheet P to the processing tray 4. Therefore, it is possible to appropriately detect the sheet P staying on the processing tray 4 without causing the conveyance resistance and the erroneous detection, and to suppress the deterioration of the retention.

  The pull-in unit 20 includes the rotary shaft 21, the swinging member 22, the movable roller 23, and the detected portion 24 configured as described above. Thus, the pull-in unit 20 can move the sheet P conveyed to the processing tray 4 toward the upstream end of the processing tray 4 in the sheet conveyance direction with a simple configuration, and the jam of the sheet P in the processing tray 4 It becomes possible to detect

  Further, since the detection target portion 24 is the side plate 22 a itself which is a frame constituting the swinging member 22, there is no need to separately prepare the detection target portion 24 as a separate member. As a result, it is possible to reduce the number of parts and the number of assembling steps.

  Further, in the drawing-in portion 20, the swinging shaft 21 includes the protrusion 21a, and the swinging member 22 includes the bearing 22b and the overhanging portion 22d. Then, when the movable roller 23 contacts the sheet P stacked on the processing tray 4 from above, one end of the swinging side of the swinging member 22 moves upward in the range of the area of the gap 22e of the overhang portion 22d. And can be rotationally displaced.

  According to this configuration, the movable roller 23 can be brought into contact with the sheet P stacked on the processing tray 4 by the action of gravity, and when the sheet P is jammed, the rocking member 22 is easily rocked. One end of the moving side can be made displaceable.

  The jam detection by the pull-in unit 20 and the detection unit 30 is performed at the start of the job using the sheet post-processing apparatus 1, and when the sheet P is detected, the job is canceled. In addition, even if a jam is detected when the number of sheets P exceeds a predetermined number during a stacking job of sheets P on the processing tray 4, the detection is ignored.

  The embodiment of the present invention has been described above, but the scope of the present invention is not limited to this, and various modifications can be made without departing from the scope of the invention.

  For example, in the above embodiment, although the image forming apparatus 101 of the image forming system S is an image forming apparatus for monochrome printing, the present invention is not limited to such a model. The image forming apparatus may be, for example, an image forming apparatus for color printing.

  The present invention can be used in a sheet post-processing device of an image forming apparatus and an image forming system provided with the sheet post-processing device.

1 sheet post-processing device 4 processing tray 5 discharge tray 7 binding section (processing unit)
8 Post-processing control unit (control unit)
DESCRIPTION OF SYMBOLS 10 discharge port 11 discharge roller pair 12 conveyance part 20 drawing-in part 21 rocking shaft 21a protrusion part 22 rocking member 22a side plate 22b bearing 22c shaft hole 22d overhang part 22e gap 23 movable roller 24 detection part 30 detection part 101 image formation Equipment S Image formation system

Claims (5)

A processing tray on which sheets are loaded;
A processing unit that performs post-processing on the sheets stacked on the processing tray;
A discharge port disposed downstream of the processing tray in the sheet conveying direction;
A discharge roller pair disposed at the discharge port;
A discharge tray on which sheets discharged from the discharge port are stacked by forward rotation of the discharge roller pair;
A conveyance unit configured to convey the sheet stacked on the processing tray toward the discharge port;
The sheet supported against the processing tray so as to freely slide, capable of contacting and separating from above with respect to the sheets stacked on the processing tray, and transported to the processing tray by reverse rotation of the discharge roller pair A drawing unit that moves a sheet toward an upstream end of the processing tray in the sheet conveyance direction;
A detection unit that detects an upward displacement beyond the predetermined position of the pull-in unit in contact with the sheets stacked on the processing tray;
A control unit that controls the operation of the discharge roller pair, the conveyance unit, and the drawing unit;
Equipped with
When the control unit moves the sheet toward the upstream end of the processing tray in the sheet conveying direction using the pull-in unit, and then a detection signal related to the upward displacement of the pull-in unit is obtained from the detection unit The sheet post-processing apparatus is characterized in that the next sheet conveyance to the processing tray is prohibited. The lead-in unit is
A swinging axis,
A swing member supported at one end side so as to be swingable about the swing shaft, and swingingly displace at the other end side;
A movable roller which is rotatably provided at one end of the swinging side of the swinging member and contacts the sheet stacked on the processing tray from above, and moves the sheet;
A detection target for detecting the displacement of the swinging member by the detection unit;
The sheet post-processing apparatus according to claim 1, comprising:   3. The sheet post-processing apparatus according to claim 2, wherein the detected portion is a frame itself that constitutes the swinging member. The rocking shaft includes a protruding portion that protrudes radially outward,
The swinging member is
A pair of side plates extending along the sheet conveying direction;
A bearing provided at one end of the supported side of the side plate and into which the rocking shaft is inserted;
Equipped with
The bearing is
An axial hole for supporting the peristaltic shaft;
An overhanging portion in which the projection is inserted by expanding the hole radially outward from the inner circumferential surface of the axial hole, and the projection has a gap which can be relatively displaced in a predetermined area in the circumferential direction;
The sheet post-processing apparatus according to claim 2 or 3, further comprising: A sheet post-processing apparatus according to any one of claims 1 to 4.
An image forming apparatus connected to the sheet post-processing apparatus to form an image on the sheet and transport the sheet after image formation to the sheet post-processing apparatus;
An image forming system comprising: