Patent Application
20170305704
The present invention relates to a sheet post-processing device that performs post-processing such as a punch hole forming process and a binding process with respect to a sheet such as a paper sheet on which an image has been formed by an image forming apparatus such as a copy machine, a facsimile, or a printer, and an image forming system provided with the same.
Conventionally, there is used a paper sheet post-processing device that is capable of executing a binding process of loading a plurality of paper sheets on each of which an image has been formed by an image forming apparatus such as a copy machine or a printer and binding together a bundle of the thus loaded paper sheets with a staple(s), a punch hole forming process of forming punch holes (perforations) therethrough by using a punch hole forming device, and so on.
In the paper sheet post-processing device described above, in performing a binding process, it is necessary that a paper sheet bundle be loaded in an aligned manner. For example, Patent Documents 1 and 2 disclose a paper sheet post-processing device provided with a carry-in roller pair that carries in a paper sheet on a processing tray and a discharge roller pair that discharges a paper sheet from the processing tray onto a discharge tray.
The discharge roller pair is composed of a discharge roll and a discharge roller that comes in pressure contact with or is separated from the discharge roll, and in a state where the discharge roller and the discharge roll are separated from each other, a paper sheet is carried in on the processing tray by the carry-in roller pair. Then, after a rear end of the paper sheet has passed through the carry-in roller pair, the discharge roller and the discharge roll are brought in pressure contact with each other and made to rotate reversely. Thus, the paper sheet is drawn in to an upstream side in a conveyance direction and comes in contact with a rear end restriction surface of the processing tray. In this manner, a paper sheet bundle on the processing tray is aligned.
Patent Document 1: JP-A-H09-156820
Patent Document 2: JP-A-2013-224221
In the method described in Patent Documents 1 and 2, however, when, in a state where paper sheets are already loaded on the processing tray, a succeeding paper sheet is drawn in, the loaded paper sheets are also drawn in together with the succeeding paper sheet, which has led to a problem that an alignment property of a paper sheet bundle is decreased.
Specifically, as shown in
In view of the above-described problem, it is an object of the present invention to provide a sheet post-processing device that, when drawing in a sheet on a processing tray by using a discharge roller pair and aligning a sheet bundle, can prevent an alignment failure of the sheet bundle, and an image forming system provided with the same.
In order to achieve the above-described object, the present invention provides a sheet post-processing device that is provided with a processing tray, a discharge tray, and a discharge roller pair. The processing tray accepts and loads thereon a prescribed number of sheets. The discharge tray is disposed on a downstream side of the processing tray in a sheet conveyance direction, and onto which sheets loaded on the processing tray are discharged. The discharge roller pair is composed of a discharge roller that comes in contact with an uppermost surface of sheets loaded on the processing tray and a discharge roll that comes in contact with a lowermost surface of the sheets loaded on the processing tray. The sheet post-processing device discharges a sheet from the processing tray onto the discharge tray by forwardly rotating the discharge roller pair, and draws in a sheet on the processing tray by reversely rotating the discharge roller in a state where the discharge roll is stopped from rotating.
According to a first configuration of the present invention, a sheet is drawn in on the processing tray by reversely rotating only the discharge roller in a state where the discharge roll is stopped from rotating, and thus a drawing-in force is exerted only on a sheet being newly carried in and not on a sheet bundle that has already been aligned on the processing tray. Accordingly, there is no fear that a sheet bundle that has already been aligned is drawn in together with a sheet being newly carried in and thus is bent, so that an alignment property of a sheet bundle on the processing tray can be effectively prevented from being decreased.
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With reference to the appended drawings, the following describes an embodiment of the present invention. First, with reference to
As shown in
In this embodiment, the main body housing 2a is composed of a lower housing 2aa and a joint housing 2ab that is positioned above the lower housing 2aa along a right side portion and joined to the upper housing 2b. In the lower housing 2aa, there are provided a paper feed portion 4 that feeds a paper sheet P, an image forming portion 6 that forms a toner image on the paper sheet P, a fixing device 7 for fixing the toner image on the paper sheet, and so on. In the joint housing 2ab, there is provided a paper sheet discharge portion (discharge portion) 18 for conveying the paper sheet P after being subjected to fixing and discharging it from the main body housing 2a.
Furthermore, on a left side of the joint housing 2ab immediately below the upper housing 2b, an intra-body paper discharge space 16 is formed that is widely open toward a left side surface and a front. In the intra-body paper discharge space 16, there is provided a relay unit 19 that accepts and loads thereon the paper sheet P discharged from a left side surface of the joint housing 2ab and, in a case of subjecting the paper sheet P to a prescribed type of post-processing, enables conveyance of the paper sheet P to the paper sheet post-processing device 20.
In the main body housing 2a, there are provided the paper feed portion 4 that is arranged in a lower portion, a paper sheet conveyance path 5 that is arranged laterally to and above the paper feed portion 4, the image forming portion 6 that is arranged above the paper feed portion 4, and a fixing portion 7 that is arranged on a downstream side of the image forming portion 6 in a paper sheet conveyance direction (a right side in
In the paper feed portion 4, there are provided a plurality of paper feed cassettes 4a that each have a separate-feed unit such as a paper feed roller provided on a downstream side in the paper sheet conveyance direction. By a rotation operation of the paper feed roller, a bundle of the paper sheets P placed in any one of the paper feed cassettes 4a are fed one by one from an uppermost one of the paper sheets P to the paper sheet conveyance path 5. By using conveyance roller pairs 5a, the paper sheet conveyance path 5 conveys the paper sheet P fed from the paper feed portion 4 to the image forming portion 6.
Inside an apparatus main body 100, the image forming portion 6 and the fixing portion 7 are arranged so as to be elongated in a width direction (a front-back direction, a direction orthogonal to a paper plane of
The image forming portion 6 forms a prescribed toner image on the paper sheet P by the electrophotographic process. The image forming portion 6 is provided with a photosensitive drum 9 that is an image carrier supported rotatably about an axis, and around the photosensitive drum 9, there are arranged along a rotation direction thereof, a charging device 11, an exposure device 12, a developing device 13, a transfer device 14, a cleaning device 15, and an unshown static elimination device. In the fixing portion 7, the paper sheet P on which a toner image has been transferred at the image forming portion 6 is sandwiched between a fixing roller pair 7a that is composed of a heating roller and a pressing roller and thus is heated and pressed so that the unfixed toner image is fixed on the paper sheet P.
In the upper housing 2b, an image reading portion 8 is provided. The image reading portion 8 reads image information of an original document. In a case where an original document is manually placed one by one so as to be read by the image reading portion 8, an auto document feeder 3 is opened, and an original document is placed on a contact glass 8a that is provided on an upper surface of the upper housing 2b. In a case where an original document is automatically supplied one by one from an original document bundle so as to be read by the image reading portion 8, the original document bundle is placed on a paper feed tray 3a of the auto document feeder 3 in a closed state. In this configuration, when an original document bundle is placed on the paper feed tray 3a, an original document is automatically and sequentially fed one by one from said original document bundle onto the contact glass 8a. In either case, an original document positioned on the contact glass 8a is irradiated with light from an unshown exposure lamp, and light reflected therefrom is guided as image light to a photoelectric conversion portion (a CCD) via an optical system such as a reflection mirror and an imaging lens (none of them is shown).
The following describes a basic operation of the image forming apparatus 100 configured as above. First, a surface of the photosensitive drum 9 that rotates counterclockwise in
Next, the paper sheet P from the paper feed portion 4 passes through the paper sheet conveyance path 5 and is conveyed at prescribed timing toward the photosensitive drum 9 on which the toner image has been formed. Further, by the transfer device 14 formed of a transfer roller or the like, the toner image on the surface of the photosensitive drum 9 is transferred on the paper sheet P. Then, the paper sheet P on which the toner image has been transferred is separated from the photosensitive drum 9 and conveyed toward the fixing portion 7. The paper sheet P is heated and pressed while passing through the fixing roller pair 7a, and thus the toner image is fixed.
After completion of a transfer process of transferring the toner image on the paper sheet P, the photosensitive drum 9 is subjected to removal of residual toner remaining on an outer circumferential surface thereof by the cleaning device 15 and then to a static elimination process of eliminating residual charge by the static elimination device (not shown). After that, the outer circumferential surface of the photosensitive drum 9 is subjected again to a charging process by the charging device 11, and thereafter, subsequent image formation is performed in a similar manner.
The paper sheet P that has passed through the fixing device 7 is conveyed, as it is, perpendicularly upward along the paper sheet conveyance path 5 into the joint housing 2ab. Inside the joint housing 2ab, an upper portion of the paper sheet conveyance path 5 is branched leftward into two upper and lower conveyance paths, and the conveyance direction of the paper sheet P is switched by a switch claw 17 that is disposed at a branching portion.
Inside the joint housing 2ab, the paper sheet discharge portion 18 is provided.
The paper sheet discharge portion 18 has an upper discharge roller pair 18a and a lower discharge roller pair 18b that is disposed immediately below the upper discharge roller pair 18a, and the paper sheet P conveyed along the paper sheet conveyance path 5 is guided to the upper conveyance path or the lower conveyance path by the switch claw 17.
When guided to the upper conveyance path by the switch claw 17, the paper sheet P is discharged leftward from the upper discharge roller pair 18a. When guided to the lower conveyance path by the switch claw 17, the paper sheet P is discharged leftward by the lower discharge roller pair 18b. A guiding direction of the switch claw 17 is switched by an unshown control portion.
The relay unit 19 is demountably mounted to a bottom surface 16a of the intra-body paper discharge space 16. In the intra-body paper discharge space 16, a detection sensor (not shown) that detects mounting of the relay unit 19 is provided. The detection sensor is formed of a PI sensor or the like and transmits a detection result to the control portion.
Furthermore, the bottom surface 16a has an inclined surface formed thereon, which is inclined upward toward a downstream side in a paper sheet discharge direction (a left side in
On the other hand, in a case where the detection sensor detects that the relay unit 19 has been mounted in the intra-body paper discharge space 16, and this detection result is transmitted to the control portion, the switch claw 17 guides the paper sheet P to the lower discharge roller pair 18b. Then, after being discharged from the lower discharge roller pair 18b, the paper sheet P is carried into the relay unit 19. The paper sheet P that has been carried into the relay unit 19 passes through the relay unit 19 and is carried into the paper sheet post-processing device 20.
It is also possible to display a detection result on an operation portion (not shown) so as to allow a user to switch, on an operation panel, the guiding direction in which the paper sheet P is guided. Furthermore, an upper surface portion of the relay unit 19 also has a function as a paper sheet discharge tray on which the paper sheet P discharged from the upper discharge roller pair 18a is placed.
Inside the paper sheet post-processing device 20, there are provided a punch hole forming device 21 that performs punch hole formation with respect to the paper sheet P that has been carried in, a processing tray 30 that loads (stacks) thereon a plurality of the paper sheets P that have been carried in, and a stapler 40 that binds a paper sheet bundle loaded on the processing tray 30 with a staple(s). On a side surface of the paper sheet post-processing device 20, a discharge tray 50 is provided that is vertically movable to a position appropriate for discharging the paper sheet P.
The punch hole forming device 21 is disposed at an upper portion in the paper sheet post-processing device 20 and forms a plurality of punch holes through the paper sheet P along either of its side end edges (a front side or a rear side of the apparatus) parallel to the conveyance direction of the paper sheet P. On an upstream side of the punch hole forming device 21 and at a substantially middle portion in a direction orthogonal to the paper sheet conveyance direction (a direction perpendicular to the paper plane of
Based on detection timing at which the tip end of the paper sheet P is detected by the carry-in detection sensor, the control portion (not shown) controls driving of the paper sheet carry-in roller pair in the relay unit 19 and thereby adjusts punch hole forming positions on the paper sheet P in the conveyance direction thereof, which is conveyed to the punch hole forming device 21. Specifically, a conveyance direction pulse adjustment value is set that is used to perform addition/subtraction to/from a reference conveyance pulse value for a period from a time when the tip end or a rear end of the paper sheet P is detected by the carry-in detection sensor to a time when the paper sheet carry-in roller pair is stopped.
Moreover, below the first discharge roller pair 27, there are provided the processing tray 30 that loads thereon, in an aligned manner, a prescribed number of the paper sheets P conveyed by the first discharge roller pair 27 and the stapler 40 (see
With respect to the paper sheet conveyance direction, on a downstream side of the processing tray 30, a second discharge roller pair 29 is arranged that discharges a paper sheet bundle from the processing tray 30 onto the discharge tray 50. The second discharge roller pair 29 is composed of a discharge roller 29a that is made of rubber and is rotatable forwardly and reversely by a drive motor (not shown) and a discharge roll 29b that is made of resin and rotates following rotation of the discharge roller 29a. The discharge roller 29a is supported by a roller holder 31 that is swingable up and down about a pivot shaft 31a as a fulcrum.
Above the processing tray 30 and on a downstream side of the first discharge roller pair 27 (a left side in
The stapler 40 is movable in the paper sheet width direction orthogonal to the conveyance direction by a movement mechanism (not shown) and, depending on how a binding process is to be performed, moves to a prescribed position along a lower end portion of the processing tray 30.
Next, a description is given of an operation of the paper sheet post-processing device 20. When the paper sheet P (shown by a broken line in
Then, the paper sheet P is conveyed further to a downstream side by the first discharge roller pair 27. At this time, as shown in
At timing at which the rear end of the paper sheet P has passed through the first discharge roller pair 27, the roller holder 31 is made to swing downward so that the discharge roller 29a is disposed at a position (contact position) where the discharge roller 29a comes in contact with the discharge roll 29b. After that, the tapping member 33 is driven to align the paper sheet P in line with the processing tray 30. In this state, the discharge roller 29a is made to rotate reversely (a counterclockwise direction in
Then, when acceptance of a bundle of the paper sheets P is completed, the stapler 40 is made to move to cut-out positions of the butting portion 30a, and rear ends of the paper sheet bundle are inserted into a staple portion 40a where a binding process with respect to the paper sheet bundle is performed. After the binding process with respect to the paper sheet bundle has been performed at the staple portion 40a, the second discharge roller pair 29 is made to rotate forwardly (an arrow direction in
Furthermore, in a case where an instruction has been given to perform shift-discharge, in discharging a paper sheet bundle onto the discharge tray 50 by driving the second discharge roller pair 29, first, the roller holder 31 is made to move to the retracted position. After that, the side end alignment cursors 60 are disposed at a position (reference position) at which the paper sheet P has been accepted or a position (shifted position) that is shifted from the reference position by a prescribed amount in a direction (paper sheet width direction) orthogonal to the discharge direction. Then, the roller holder 31 is made to move to the contact position so that the paper sheet is discharged. Thus, a paper sheet bundle is discharged alternately to a reference discharge position on the discharge tray 50 and to a shifted discharge position that is shifted from the reference discharge position by a prescribed amount in the direction (paper sheet width direction) orthogonal to the discharge direction, so that when discharged onto the discharge tray 50 (see
In the paper sheet post-processing device 20 of this embodiment, the discharge roll 29b that is a component of the second discharge roller pair 29 is configured to be rotatable only in a forward direction (the counterclockwise direction in
By this configuration, as shown in
As a method for configuring the discharge roll 29b to be rotatable only in a forward direction, for example, a one-way mechanism that is rotatable only in one direction, such as a one-way gear or a one-way clutch, is built into a rotary shaft of the discharge roll 29b.
Furthermore, the roller holder 31 supporting the discharge roller 29a is configured to be swingable, and thus the discharge roller 29a can be easily switched in its position between the position (retracted position) away from the discharge roll 29b and the position (contact position) where the discharge roller 29a comes in contact with the discharge roll 29b.
Other than the above, the present invention is not limited to the above-described embodiment, and various modifications thereto are possible without departing from the spirit of the present invention. For example, while the above-described embodiment has been described by using, as an example, a configuration in which the image forming apparatus 100 and the paper sheet post-processing device 20 are directly connected to each other, the present invention is applicable also to a configuration in which an insertion device that inserts interleaving paper is installed between the image forming apparatus 100 and the paper sheet post-processing device 20.
The present invention is usable in a sheet post-processing device that loads sheets in an aligned manner on a processing tray by using a discharge roller pair. The use of the present invention can provide a sheet post-processing device that, in drawing in a sheet on a processing tray by using a discharge roller pair and aligning a sheet bundle, can prevent an alignment failure of the sheet bundle, and an image forming system provided with the same.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2015-068076 | Mar 2015 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2015/080888 | 11/2/2015 | WO | 00 |
