JP4440858B2 - Paper transport device, paper post-processing device, and image forming apparatus - Google Patents

Description

  The present invention is provided in an image forming apparatus such as a copying machine, a printer, a plotter, a facsimile machine, and a printing apparatus, and includes a sheet conveying apparatus that conveys a sheet after image formation to a processing tray, and the sheet conveying apparatus. The present invention relates to a sheet post-processing apparatus having a function of performing post-processing, and an image forming apparatus including the sheet conveying apparatus or the sheet post-processing apparatus.

Various image forming devices such as electrophotographic copying machines, printers, plotters, facsimiles, ink jet printers, printing devices, etc. have a paper post-processing device that performs paper alignment, binding, stacking, etc. after image formation. Or what was built in is known conventionally.
On the other hand, the copy speed (CPM) and the print speed (PPM) of the image forming apparatus are increasing, and accordingly, the paper post-processing apparatus also retracts or stays in the machine so that CPM and PPM do not go down. In addition, a function for receiving a sheet from the image forming apparatus side is essential between jobs (JOBs), and a sheet post-processing apparatus having a sheet retention mechanism inside has been proposed (for example, Patent Document 1, Patent Document 1). 2, 3, 4 etc.).

  More specifically, in the paper post-processing apparatus, the image-formed paper output from the image forming apparatus is transported in the transport path by a paper transport unit including a plurality of transport rollers and the like, and is positioned downstream of the transport path. After stacking while aligning with the tray, for example, a binding process is performed by a stapler, and the bound sheet bundle is discharged to a discharge tray or the like by discharge means such as a discharge belt. The stapler's binding processing operation is performed by a staple signal from the control means between the last sheet of the sheet bundle and the first sheet of the next sheet bundle. In other words, when the number of copies to be processed is two or more, the image forming apparatus is arranged so that the first sheet of the next part is discharged to the processing tray at the end of stapling and discharging on the processing tray. Control is performed to increase the copy interval (or print interval) between the final sheet of one copy and the first sheet of the next copy.

  As described above, when the paper post-processing apparatus is used, since the copying operation (printing operation) is stopped between the units, there is a problem that the productivity is low. In order to deal with this problem, apart from the main conveyance path for guiding paper to the processing tray, another conveyance path (hereinafter referred to as a retention conveyance path) that merges with the main conveyance path is formed, and the post-processing tray During the stapling process of the previous part, the output paper is guided to the staying conveyance path and waited, and the main conveyance path is merged with the next sheet conveyed and processed in a superimposed state. A method of transporting and stacking on a tray has been proposed.

JP-A-8-301508 Japanese Patent Laid-Open No. 9-235069 Japanese Patent No. 3417994 JP-A-11-199128

In the conventional paper post-processing device, the retention mechanism of the conveyance device is also provided with a conveyance means for the retention conveyance path for retaining the paper, and is conveyed to the conveyance means in the retention conveyance path by the conveyance means of the main conveyance path. Further, the sheet is conveyed upstream by the conveying means in the stay conveying path, the leading edge of the sheet is stopped between the switching means and the downstream conveying means, and the sheet is supported by the conveying means in the stay conveying path. . For this reason, the amount of misalignment between the sheets can be adjusted by activating the conveying means of the staying conveyance path at the same position as the leading edge of the remaining sheet.
However, in the configuration of the staying mechanism of the conventional paper transporting device, the transporting means is also provided in the staying transporting path, which increases the cost.

In view of this, the present inventors have studied to reduce the cost of the staying mechanism of the paper transporting device by eliminating the transporting means of the staying transport path.
However, when the staying conveyance path has no conveyance means, the stop position of the leading edge of the sheet is downstream of the conveyance means (for example, a conveyance roller pair) on the downstream side of the switching means. For this reason, it is impossible to carry the sheet until the leading edge of the next sheet reaches the leading edge of the staying sheet, and a deviation occurs between the leading edge of the remaining sheet and the leading edge of the next sheet. Also, if the start timing of the transport means downstream from the switching means is advanced, the transport of the staying preceding paper is started first, and the amount of deviation between the preceding paper and the next paper becomes large. There is a problem that the alignment accuracy in the processing tray deteriorates.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and even if no conveying means is provided in the staying conveyance path, the sheets are aligned on the downstream side of the switching means provided at the branching portion of the main conveyance path and the staying conveyance path. It is an object of the present invention to provide a paper transport device having a configuration that can prevent deterioration in accuracy. Furthermore, the present invention provides a sheet post-processing apparatus and an image forming apparatus that include the sheet conveying device, can prevent deterioration in alignment accuracy downstream of the switching unit, and can improve alignment accuracy on the processing tray. The purpose is to provide.

In order to achieve the above object, the present invention employs the following solutions.
First means of the present invention, an incoming paper sheet received from the preceding apparatus, the sheet transport apparatus for transporting the processing tray for postprocessing, a main transport path for guiding the sheet to the processing tray, the main transfer has a first conveying means and second conveying means for conveying the sheet provided for the road prior Symbol processing tray, and a conveying path for retention to dwell temporarily paper branched from the main transport path, the second conveying means and the processing tray the paper conveyed in the reverse direction (hereinafter, regurgitation and referred) and that capable of constituting, the paper when said main transport path is flowing back the paper Switching means for guiding the air to the retention transport path, wherein the first transport means is provided on the upstream side of the switching means and the second transport means is provided on the processing tray side of the switching means. , The preceding paper is the second carrying When the leading edge of the next sheet is conveyed between the switching means of the main conveyance path and the second conveyance means by the first conveyance means. The second transporting unit is activated, and the second transporting unit transports the preceding sheet and the next sheet toward the processing tray in a state of being overlaid (Claim 1).

Second means of the present invention, in the conveyance apparatus of the first means, the preceding paper is distilled stagnation the residence conveyance path while being held by the second conveying means, by said first conveying means when the leading edge of the following sheet is transported between the switching means and the second conveying means of said main transport path, the transport speed at which the sheet reaches the second conveying means, said first conveying means It is characterized by being slower than the conveyance speed (claim 2 ).

Third means of the present invention, the sheet conveying apparatus of the first or second means, the preceding paper is distilled stagnation the residence conveyance path while being held by the second conveying means, said first when the leading edge of the following sheet is transported between the second transport means and the switching means of the main conveying path by the conveying means, the conveying speed of the second conveying means, the next sheet is the second conveying means After a short time after being conveyed, the speed is the same as the conveying speed of the first conveying means (claim 3 ).
According to a fourth means of the present invention, in the paper transport device of any one of the first to third means, when there is no paper in the staying transport path, the start timing of the second transport means is set. The timing is the same as the start timing of the first conveying means (claim 4 ).

According to a fifth means of the present invention, in the paper transport device of any one of the first to fourth means, when the paper size is not transported to the staying transport path, the start timing of the second transport means Is set to the same timing as the start timing of the first conveying means (Claim 5 ).
According to a sixth means of the present invention, in the paper transport device of any one of the first to fifth means, when the paper type is not transported to the stay transport path, the second transport means The activation timing is set to be the same timing as the activation timing of the first conveying means (Claim 6 ).
Further, according to a seventh means of the present invention, in the paper conveying apparatus of any one of the first to sixth means, when the paper type is not conveyed to the stay conveying path, the second conveying means is activated. the timing, is characterized by the same timing as the timing of starting the first conveying means (claim 7).

According to an eighth aspect of the present invention, there is provided a sheet post-processing apparatus having a function of post-processing an image-formed sheet, the sheet conveying apparatus according to any one of the first to seventh aspects, and the sheet conveying apparatus. A processing tray that is positioned downstream of the main transport path and performs post-processing of the paper, and a paper discharge tray that stacks the paper processed in the processing tray. The processing tray is transported through the main transport path. The apparatus includes: an alignment unit that stacks and aligns incoming sheets; a binding unit that binds the aligned sheet bundle; and a discharge unit that discharges the sheet bundle bound by the binding unit to the discharge tray. (Claim 8 ).

Ninth means of the present invention, there is provided an image forming apparatus is characterized by comprising a sheet conveying apparatus of the first to seventh any one means (claim 9).
The tenth means of the present invention is characterized by comprising the paper post-processing device of the eighth means (claim 10 ).

First in the paper conveying apparatus means, a main transport path and the first conveying means and second conveying means for transporting the processing tray the sheets provided to the main conveying path for guiding the sheet to the processing tray of the present invention When, and a retention transport path to dwell temporarily paper branched from the main transport path, capable second transport means from the processing tray to the paper conveying (backflow) in the opposite direction composed of The main transport path has switching means for guiding the paper to the staying transport path when the paper is made to flow backward, the first transport means is provided on the upstream side of the switching means, and the second transport means is Provided on the processing tray side from the switching means, the preceding sheet is retained in the retention conveyance path while being held by the second conveyance means, and the leading edge of the next sheet is switched by the first conveyance means to the main conveyance path And second transport means when transported between the second transport means Start feeding means, since it is characterized in that for transporting the processing tray in a state of superposed paper and the next paper to be preceded by a second conveying means, without providing a conveying means for retention conveying path, By delaying the start timing of the second conveying means and reducing the amount of misalignment between the staying paper and the leading edge of the next paper, it becomes possible to prevent deterioration in alignment accuracy downstream from the switching means. .

In the sheet conveying apparatus of the second means of the present invention, in addition to the configuration of the first means, the sheet is retained in the retention conveying path, and the next sheet is conveyed downstream of the switching means of the main conveying path. The transport speed when the paper reaches the second transport means is slower than the transport speed of the first transport means, so that the amount of misalignment between the staying paper and the leading edge of the next paper is reduced. Can do.
In addition, in the sheet conveying apparatus of the third means of the present invention, in addition to the configuration of the first or second means, the sheet is retained in the retention conveying path, and the next sheet is downstream of the switching means of the main conveying path. when, which has been conveyed, the conveying speed of the second conveying means, by the following sheet is the conveying speed and the speed of the first conveying means from a little from being conveyed to the second conveying means, The amount of misalignment between the staying paper and the leading edge of the next paper can be further reduced.
Further, in the sheet conveying apparatus of the fourth means of the present invention, in addition to the configuration of any one of the first to third means, when there is no sheet in the stay conveying path, the second conveying means By making the activation timing the same as the activation timing of the first conveying means, it is possible to efficiently carry the paper when the sheet is not retained.

In the paper conveying apparatus of the fifth means of the present invention, in addition to the configuration of any one of the first to fourth means, the second conveying means is activated when the paper size is not conveyed to the stay conveying path. By setting the timing to the same timing as the start timing of the first conveying means, even when using a large size paper that does not fit in the stay conveyance path, the large size paper is smoothly conveyed to the processing tray. be able to.
In the paper conveying apparatus of the sixth means of the present invention, in addition to the configuration of any one of the first to fifth means, the second paper is used when the paper thickness is not conveyed to the stay conveying path . By setting the start timing of the transport means to the same timing as the start timing of the first transport means, even when using a thick paper that is not transported (or cannot be transported) to the stay transport path, It can be smoothly transported to the processing tray.
Further, in the sheet conveying apparatus of the seventh means of the present invention, in addition to the configuration of any one of the first to sixth means, in the case of a sheet type not conveyed to the stay conveying path, the second conveying means By setting the start timing to the same timing as the start timing of the first transport means, it is easy to be charged with static electricity such as an OHP sheet, tressing paper, etc. Even when using a sheet that is likely to cause a conveyance failure, the sheet can be smoothly conveyed to the processing tray.

According to an eighth aspect of the present invention, there is provided a sheet post-processing apparatus, the sheet conveying apparatus according to any one of the first to seventh aspects, and a post-processing of the sheet that is located downstream of the main conveying path of the sheet conveying apparatus. And a paper discharge tray for stacking sheets processed in the processing tray, and the processing tray includes alignment means for stacking and aligning sheets conveyed through the main conveyance path, By having a binding unit that binds the aligned sheet bundle and a discharge unit that discharges the bundle of sheets bound by the binding unit to the discharge tray, the alignment accuracy of the sheets conveyed to the processing tray is deteriorated in advance. It is possible to prevent this, and it is possible to improve the alignment accuracy and the binding accuracy on the processing tray.

In the ninth and tenth image forming apparatuses of the present invention, the sheet conveying apparatus of any one of the first to seventh means or the sheet post-processing apparatus of the eighth means is provided, so that the processing is performed. It is possible to prevent deterioration in alignment accuracy of the paper conveyed to the tray, improve alignment accuracy and binding accuracy on the processing tray, and obtain a well-aligned paper bundle.

  FIG. 1 is a diagram illustrating a system configuration of an image forming system including a sheet post-processing apparatus and an image forming apparatus according to an embodiment of the present invention. In FIG. 1, the entire sheet post-processing apparatus and a part of the image forming apparatus are illustrated. Is shown. 2 to 6 are diagrams illustrating an example of the operation of the sheet conveying device in the sheet post-processing apparatus, and FIG. 7 is a diagram illustrating a configuration example of a control system of the sheet post-processing apparatus.

In FIG. 1, the sheet post-processing apparatus 200 is attached to a side portion of the image forming apparatus 100, and the image-formed sheet P discharged from the image forming apparatus 100 is guided to the sheet post-processing apparatus 200.
In this embodiment, the image forming apparatus 100 performs optical writing on a drum-shaped or belt-shaped image carrier (for example, a photoconductive photosensitive member) based on input image data, and forms a latent image on the surface of the photosensitive member. The image forming apparatus uses a so-called electrophotographic process in which a latent image formed is developed with colored particles such as toner, transferred to a recording medium such as paper, fixed, and discharged. Note that since an image forming apparatus using an electrophotographic process is known per se, a detailed description and illustration thereof will be omitted here. In this embodiment, an image forming apparatus using an electrophotographic process is illustrated, but it goes without saying that a system using a known image forming apparatus such as an ink jet printer or a printing apparatus may be used. .

In the present embodiment, the sheet post-processing apparatus 200 is provided side by side on the image forming apparatus 100, but may be provided in the image forming apparatus.
The paper discharged from the image forming apparatus 100 is guided to the paper post-processing device 200, conveyed by a pair of inlet rollers (hereinafter simply referred to as an inlet roller) 1, and processing means for processing one sheet (this embodiment) Then, the paper is transported by a pair of transport rollers (hereinafter simply referred to as transport rollers) 2 through an introduction transport path A1 having a punch unit 19) as a punching means, reaches a branching portion, and is directly guided to the paper discharge tray 23. Branches to the main conveyance paths A2 and A3 leading to the processing tray 11 (hereinafter also referred to as a staple processing tray) for performing alignment and stapling processing through the path A5 or the conveyance rollers 3, 5, 6 and the staple conveyance roller 7. It is comprised so that it may distribute with the nail | claws 20 and 21. FIG.

The tray surface on which the sheets P of the staple processing tray 11 are stacked is inclined so that the downstream side in the conveyance direction of the sheet discharged from the staple conveyance roller 7 is upward, and the inclination angle is inclined with respect to the gravity direction. The minimum angle is set so as not to interfere with a mechanism such as the end face binding stapler 12 on the lower side of the surface.
Further, the sheet guided to the staple processing tray 11 through the main transport paths A2 and A3 and subjected to alignment, stapling, and the like in the staple processing tray 11 is transported upward by a discharge belt 14 serving as a discharge unit, and is discharged. 16 and the paper discharge roller 22 to be discharged to the paper discharge tray 23.

The main transport path is composed of an upstream transport path A2 and a downstream transport path A3, and the connection between the upstream transport path A2 and the downstream transport path A3 branches off from the main transport path and temporarily retains paper. The transfer path A4 is provided, and a switching claw 9 as a switching means is arranged at the branch portion, and is held in the state shown in the figure by a low-load spring or the like (not shown), and the rear end of the sheet has passed through it. Thereafter, at least the transport rollers 5 of the transport rollers 5 and 6 and the staple transport rollers 7 on the downstream side of the switching claw 9 are reversed to guide the rear end of the paper to the retention transport path A4 to retain the paper. And can be conveyed in a superimposed manner. By repeating this operation, two or more sheets can be stacked and conveyed.
The staple conveying roller 7 is composed of a drive roller and a driven roller that can be rotated forward and backward, and the driven roller side is supported by a contact / separation mechanism including a holding member 15 and a contact / separation lever 18 and is in contact with the drive roller. It can be separated.

  An inlet conveyance path A1 that is common to the upstream of the main conveyance path A2 and the discharge conveyance path A5 has an inlet sensor SN1 that detects the sheet P received from the image forming apparatus 100, an inlet roller 1 and a punch unit 19 downstream thereof. The conveying roller 2 and the branching claws 20 and 21 are sequentially arranged. The branching claws 20 and 21 are normally rotated downward by a spring or the like (not shown) so as to close the main conveyance path A2 and directly convey one sheet P to the sheet discharge tray 23 via the sheet discharge conveyance path A5. However, when processing such as alignment and stippling is performed based on input information from the image forming apparatus 100, the branching claws 20 and 21 are moved upward as shown in FIG. It will be in the state which turned, and will be in the state which guides a sheet | seat to the main conveyance path A2 side.

  In this sheet post-processing apparatus 200, punching by the punch unit 19, sheet alignment by the staple processing tray (alignment fence 17, end-face stitching stapler 12, etc.) + edge binding, sorting by the sheet discharge tray 23, etc. Can be processed.

<Stipple processing tray>
In the processing tray 11 that performs paper alignment and stapling processing (edge binding or the like), the paper P guided to the processing tray 11 by the staple transport rollers 7 through the main transport paths A2 and A3 is sequentially stacked on the tray surface. The stacking of the sheets P is detected by a sheet presence / absence sensor SN3 that detects the presence / absence of sheets on the staple processing tray 11. When the loading of the paper P is detected, the paper rollers 8 are aligned in the vertical direction (paper transport direction) with the tapping roller 8 and are aligned in the horizontal direction (paper width direction orthogonal to the paper transport direction) by the alignment fence 17. Matching is done. Thereafter, the end-face stitching stapler 12 is driven by a stapling signal from a control device (not shown) between a job (JOB) break, that is, from the last sheet of the sheet bundle to the first sheet of the next sheet bundle, and the binding process is performed. The sheet bundle subjected to the binding process is immediately sent to the paper discharge roller 22 by the discharge belt 14 having the discharge claws 10 (10a, 10b), and is discharged to the paper discharge tray 23 set at the receiving position.

  The discharge claw 10a is configured such that its home position (HP) position is detected by a discharge belt HP sensor SN4. The discharge belt HP sensor SN4 is turned on / off by a discharge claw 10a provided on the discharge belt 14. Two discharge claws 10a and 10b are arranged at opposite positions on the outer periphery of the discharge belt 14, and the sheet bundle stored in the staple processing tray 11 is moved and conveyed alternately. Further, the sheet bundle accommodated in the processing tray 11 on the back surface of the discharge claw 10b on the side opposite to the discharge claw 10a waiting to move the sheet bundle by rotating the discharge belt 14 in reverse. It is also possible to align the tips in the transport direction.

  The hitting roller 8 provided opposite to the staple processing tray 11 is given a pendulum motion by a hitting solenoid (SOL) (not shown) around a fulcrum, and intermittently acts on the paper fed to the staple processing tray 11 to thereby change the paper. Is abutted against the rear end fence 13. The hitting roller 8 rotates counterclockwise. The alignment fence 17 is driven via a timing belt by a jogger motor (not shown) capable of forward and reverse rotation, and reciprocates in the paper width direction.

  The end-face stitching stapler 12 is driven via a timing belt by a forward / reversely movable stapler moving motor (not shown), and moves in the sheet width direction in order to bind a predetermined position of the sheet edge. A stapler movement HP sensor (not shown) for detecting the home position (HP) of the end-face stitching stapler 12 is provided at one side end of the movement range, and the binding position in the sheet width direction is the end-face stitching stapler 12 from the home position. It is controlled by the amount of movement.

<Control device>
As shown in FIG. 7, the control device 300 of the paper post-processing device includes a central processing unit (CPU) 310, an I / O interface 320, memories (ROM, RAM) not shown, a clock, a timer, various drivers, and the like. It consists of a microcomputer and is connected to the control unit 100A on the image forming apparatus main body side. Then, setting information (setting information input by each switch on a control panel (not shown) and the like) and control information from the control unit 100A on the image forming apparatus main body side, an inlet sensor SN1, a paper sensor SN2, a paper presence sensor SN3, and a discharge belt A signal from each sensor such as the HP sensor SN4 is input to the CPU 310 via the I / O interface 320.

  The CPU 310 performs a tray lifting motor for the paper discharge tray 23 based on the input signal, a shift motor for moving the paper discharge tray 23, a hitting roller motor for driving the hitting roller 8, a solenoid such as a hitting solenoid (SOL), A transport motor for driving the transport roller, a paper discharge motor for driving the paper discharge roller, a discharge motor for driving the discharge belt 14, a stapler moving motor for moving the end surface binding stapler 12, an oblique motor for rotating the end surface binding stapler 12 diagonally, The drive of the motor etc. which move the alignment fence 17 is controlled. Further, the punch unit 19 performs drilling according to an instruction from the CPU 310 by controlling a clutch and a motor.

  The sheet post-processing apparatus 200 is controlled by the CPU 310 executing a program written in a ROM of a memory (not shown) while using a RAM (not shown) as a work area. Program data is stored in a hard disk device (not shown) via a recording medium driving device from a server or from a recording medium such as a CD-ROM, a card memory, or a USB memory instead of or in addition to the ROM. It can also be used after being downloaded to a medium or upgraded.

<Operation>
The outline of the sheet post-processing apparatus according to the present invention and the image forming system including the same has been described above. Next, the operation of the sheet conveying apparatus in the sheet post-processing apparatus will be described.

(Operation example 1)
In the paper transport device according to the present invention, the staying transport path A4 can retain a plurality of sheets of paper P, and transport means (transport rollers 5, 6) downstream from the switching claw 9 of the main transport paths A2, A3. ) Is a configuration capable of transporting the paper P1 retained in the retention transport path A4 to the staple processing tray 11 so as to overlap the next paper P2 sent to the main transport paths A2 and A3. The conveying means (conveying rollers 2, 3) on the upstream side of the switching claw 9 of the main conveying paths A2, A3 and the conveying means (conveying rollers 5, 6, 7) on the downstream side are configured to control driving separately. . Therefore, even if no conveying means is provided in the staying conveyance path A4, the leading ends of the preceding paper P1 and the next paper P2 staying with the start timing of the downstream conveying means (conveying rollers 5, 6, 7) being delayed. By reducing the amount of deviation, it is possible to prevent deterioration in alignment accuracy on the downstream side of the switching claw 9 in advance.

(Operation example 2)
In the paper transport device according to the present invention, when the paper P1 stays in the staying transport path A4 and the next paper P2 is transported to the downstream side of the switching pawl 9 of the main transport paths A2 and A3, the switching pawl. The transport speed when the paper P2 reaches the transport means (transport rollers 5, 6, 7) on the downstream side of 9 is slower than the transport speed of the transport means (transport rollers 2, 3) on the upstream side of the switching claw 9. The drive is controlled so that As a result, the amount of misalignment between the leading and remaining sheets P1 and P2 can be further reduced.

(Operation example 3)
In the paper transport device according to the present invention, when the paper P1 stays in the staying transport path A4 and the next paper P2 is transported to the downstream side of the switching pawl 9 of the main transport paths A2 and A3, the switching pawl. The conveying speed of the conveying means (conveying rollers 5, 6, 7) on the downstream side of 9 is slightly upstream after the next sheet P2 is conveyed to the conveying means (conveying rollers 5, 6, 7) on the downstream side. The drive is controlled so as to be the same speed as the conveying speed of the conveying means (conveying rollers 2 and 3) on the side. As a result, the amount of misalignment between the leading and remaining sheets P1 and P2 can be further reduced.

(Operation example 4)
In the sheet conveying apparatus according to the present invention, when there is no sheet in the stay conveying path A4, the start timing of the conveying means (conveying rollers 5, 6, 7) on the downstream side of the switching claw 9 is set to the upstream conveying means. The drive is controlled so as to be the same timing as the start timing of (conveying rollers 2 and 3). Thereby, conveyance when the paper P is not retained can be performed efficiently.

(Operation example 5)
In the paper transport device according to the present invention, when the paper size is not transported to the stay transport path A4, the start timing of the transport means (transport rollers 5, 6, 7) downstream from the switching claw 9 is set to the upstream side. The drive is controlled so as to be the same timing as the start timing of the transport means (transport rollers 2 and 3). As a result, even when using a large size paper that does not fit in the retention transport path A4, the large size paper can be smoothly transported to the staple processing tray 11.

(Operation example 6)
In the paper transport device according to the present invention, when the paper thickness is not transported to the stay transport path A4, the start timing of the transport means (transport rollers 5, 6, 7) on the downstream side of the switching claw 9 is set upstream. The drive is controlled so as to be the same timing as the start timing of the side conveying means (conveying rollers 2 and 3). Accordingly, even when a thick paper sheet that is not transported (or cannot be transported) is used in the stay transport path A4, the paper can be transported smoothly to the staple processing tray 11.

(Operation example 7)
In the paper transport device according to the present invention, in the case of a paper type that is not transported to the stay transport path A4, the start timing of the transport means (transport rollers 5, 6, 7) downstream from the switching claw 9 is set to the upstream side. The drive is controlled so as to be the same timing as the start timing of the transport means (transport rollers 2 and 3). As a result, even when a paper type that is not (or cannot be transferred) to the staying conveyance path A4 (for example, a sheet that is easily charged with static electricity such as an OHP sheet or a tressing paper, or the like is likely to cause a conveyance failure) is used. Can be smoothly conveyed to the staple processing tray 11.

  The operation example of the paper conveying apparatus according to the present invention has been described above. Next, specific examples of the operation will be described.

Example 1
First, the outline of the operation of the sheet post-processing apparatus of the present invention will be described with reference to FIG. The sheet P output from the image forming apparatus 100 enters the sheet post-processing apparatus 200, detects the sheet P by the entrance sensor SN1, is transported by the entrance roller 1 and the transport roller 2 of the sheet transport apparatus, Is introduced to the upstream side A2 of the main transport path, transported by the transport roller 3, and the switching claw 9 as the switching means is rotated by the moving force of the paper P, and passes through the main transport path downstream side A3 secured thereby. Then, the sheet is conveyed to the processing tray (stipple processing tray) 11 through the conveying roller 5, the conveying roller 6, and the staple conveying roller 7. The transported paper P falls by its own weight in the direction of arrow B, and the transport direction is aligned by the rear end fence 13. The trailing edge of the sheet P is detected by the sheet sensor SN2 in advance, and the width direction is aligned by the alignment fence 17 after a time during which the sheet conveyance direction can be aligned. By repeating this operation, a large number of sheets P are aligned one by one. The above is the operation in the case of one copy.

  Next, the operation of two or more parts will be described below. The interval between the sheets P output from the image forming apparatus 100 is constant, and the interval between JOBs is also output constant. When the first copy is output from the control unit 100A of the image forming apparatus 100, signals such as the size, number of sheets, transport speed, and processing mode of the paper P are sent. When the CPU 310 of the control device 300 on the sheet post-processing device 200 receives the signal, the number of sheets P to be stacked, the acceleration point, the acceleration linear velocity, the backflow point, the stop point at the time of stacking, and the like are determined.

  Here, the actual sheet processing operation will be described with reference to FIGS. 1 and 2A to 2D. The leading sheet P1 of the JOB output from the image forming apparatus 100 is transported by the entrance roller 1 and the transport rollers 2 and 3 of the sheet transport apparatus provided in the sheet post-processing apparatus 200, and the switching claw in the main transport paths A2 and A3. 9 is conveyed to the position of FIG. At this time, when it is necessary to reverse the sheet P1 by a signal from the control unit 100A of the image forming apparatus 100, the conveyance rollers 5 and 6 on the downstream side of the switching claw 9 and the rotation guide at the entrance of the retention conveyance path A4. 4 stops once, starts reverse rotation in the direction of the arrow shown in FIG. 2B, and the switching claw 9 is activated and transported to the stay transport path A4. The distance transported to the stay transport path A4 is controlled by the CPU 310 of the control device 300 based on the pulse count from the entrance sensor SN1, a timer, and the like so that it stops when the front end position is the same regardless of the paper size. Control. At this time, the paper P <b> 1 is stopped in a state of being bitten by the nip of the transport roller 5.

  Next, as shown in FIG. 2C, the second sheet (next sheet) P <b> 2 is conveyed by the conveying roller 3 on the upstream side of the switching claw 9. Then, the sheet P1 stacked in the staying conveyance path A4 as shown in FIG. 2C by the detection information of the entrance sensor SN1 is conveyed in the direction of the arrows as shown in FIG. Rotates and starts conveying. Since the leading sheet P1 of the JOB staying in the retention transport path A4 is re-conveyed while being in the nip of the conveying roller 5, the leading edge of the leading sheet of JOB precedes the leading edge of the second sheet. In the state, two sheets are simultaneously discharged to the staple processing tray 11. In the discharged sheet bundle, the discharge claw 10 provided in the discharge belt 14 of the staple processing tray 11 rotates in the direction of arrow D, and the front end of the discharge claw 10 is hit with the back, and the sheets P1 and P2 are fed to the rear end fence 13. To adjust the misalignment in the transport direction. Thus, post-processing can be performed without reducing the productivity and binding quality of the image forming apparatus main body.

  The above is the conveyance situation in the case of two sheets. Further, when stacking two sheets and three sheets depending on the processing contents in the staple processing tray 11 and earning between JOBs, the above operation is repeated without dropping the CPM (or PPM) of the main body of the image forming apparatus. Post-processing can be performed.

  In the above description, the rotation guide 4 and the transport rollers 5 and 6 are driven in the same way, but the same operation is possible even in separate driving. Further, even if the rotation guide 4 is not driven and the rotation guide 4 is rotated by its own weight, the post-processing can be performed without any problem without reducing the productivity of the main body.

(Example 2)
Next, a method for starting the conveyance roller on the downstream side of the switching claw 9 will be described below.

(I) When the paper stays in the staying transport path The movement of the paper and the transport roller when the preceding paper P1 stays in the staying transport path A4 is shown in FIGS. This will be described with reference to (a) and (b).

  As shown in FIG. 3A, when the preceding paper P1 is in the staying transport path A4 and the next paper P2 turns on the entrance sensor SN1, the entrance roller 1, the transport rollers 2 and 3 are activated. At this time, the conveyance rollers 5 and 6 and the staple conveyance roller 7 on the downstream side of the switching claw 9 of the main conveyance path are in a stopped state. Next, as shown in FIG. 3B, the transport rollers 5 and 6 and the staple transport roller 7 are activated immediately before the leading edge of the next sheet P <b> 2 enters the nip of the transport roller 5. As described in the above operation example, the trigger to be activated is activated by controlling the driving by the CPU 310 based on the information of the entrance sensor SN1. At this time, the linear speed Va of the transport rollers 2 and 3 on the upstream side of the switching claw 9 is faster than the linear speed Vb of the transport rollers 5 and 6 and the staple transport roller 7 on the downstream side of the switching claw 9. As shown in b), the next sheet P2 bends. Here, since the paper P2 is wrinkled or scratched if the amount of bending becomes large, the amount of bending is adjusted by the start timing of the transport rollers 5 and 6 and the staple transport roller 7.

  Next, when the sheets P1 and P2 overlapped as shown in FIG. 4A are conveyed by a certain amount by the conveying roller 5, the linear velocity Va of the conveying rollers 2 and 3 on the upstream side of the switching claw 9 is switched. The linear speed Vb of the transport rollers 5 and 6 and the staple transport roller 7 on the downstream side of the claw 9 is constant and transported. At this time, the bending of the paper P2 is as shown in FIG. Then, as shown in FIG. 4B, when the next sheet P2 passes through the conveying roller 3, the bending is eliminated, and the subsequent processing is discharged to the staple processing tray 11 with the sheets P1 and P2 overlapping as described above. Are aligned. By performing such an operation, it is possible to adjust the shift amount of the sheets P1 and P2, and to perform processing without reducing the downstream alignment accuracy and without reducing the productivity.

(Ii) When there is no paper in the staying transport path (in the case of paper of a size, thickness, and type that is not transported (or cannot be transported) to the staying transport path)
The movement of the paper and the transport roller when there is no paper in the staying transport path A4 will be described with reference to FIGS. 5 (a), 5 (b), 6 (a), and 6 (b).

  First, when there is no sheet in the staying conveyance path A4, the same operation as the above (i) (the start timing of the conveyance rollers 5, 6 and the staple conveyance roller 7 on the downstream side of the switching claw 9 is delayed and switched. Trouble when the linear velocity Va of the conveying rollers 2 and 3 upstream of the claw 9 and the linear velocity Vb of the conveying rollers 5 and 6 downstream of the switching claw 9 and the staple conveying roller 7 are not uniform) An example will be described with reference to FIGS. 5A and 5B, taking the case of a large size sheet as an example.

  When there is no sheet in the staying conveyance path A4 as shown in FIG. 5A, when the large sheet P is used and the punch unit 19 performs punching in the mode similar to the above (i), As shown in FIG. 5B, the point at which the punch is punched by the punch unit 19 is downstream rather than the point at which the leading edge of the paper P reaches the transport roller 5 downstream of the switching claw 9, so the paper P is bent. Therefore, there is a possibility that the upstream conveying rollers 2 and 3 may slip. And since the punch unit 19 is punching using the information of OFF of entrance sensor SN1 as a trigger, the malfunction that the punch hole position Q will shift | deviate arises.

  Therefore, in order to prevent this from happening, in the case of paper that is not conveyed to the retention conveyance path A4, the activation timing of the conveyance rollers 5 and 6 and the staple conveyance roller 7 on the downstream side of the switching claw 9 is changed to the switching claw. At the same time as the inlet roller 1 and the transport rollers 2 and 3 upstream of 9, the transport speed is made constant.

That is, in the present invention, when there is no sheet in the staying conveyance path A4, when the sheet P turns on the inlet sensor SN1 as shown in FIG. 6A, the inlet roller 1 and the conveyance roller 2 on the upstream side of the switching claw 9. , 3 and the transport rollers 5 and 6 and the staple transport roller 7 on the downstream side of the switching claw 9 are simultaneously activated and driven at a constant speed. Next, as shown in FIG. 6B, when the paper P is conveyed to the conveying roller 5 downstream of the switching claw 9, the linear velocity Va of the conveying rollers 2 and 3 upstream of the switching claw 9 and the switching claw 9. Since the linear speeds Vb of the transport rollers 5 and 6 and the staple transport roller 7 on the downstream side are constant, the sheet P is transported to the staple processing tray 11 without being bent. Therefore, it is possible to punch at an appropriate position R even in the case of a large size sheet.
In addition, when using thick paper or special types of paper (for example, paper that is easily charged with static electricity such as an OHP sheet, tressing paper, etc.), the same operation as described above is performed. The paper can be smoothly conveyed to the staple processing tray 11 and post-processed.

1 is a schematic configuration diagram illustrating a system configuration of an image forming system including a sheet post-processing apparatus and an image forming apparatus according to an embodiment of the present invention. It is a figure which shows an example of the processing operation of the paper post-processing apparatus which concerns on this invention. It is a figure which shows the operation example of the conveying apparatus of the paper post-processing apparatus which concerns on this invention. FIG. 4 is a diagram illustrating an operation example continued from the operation illustrated in FIG. 3. FIG. 10 is a diagram illustrating an operation example in which a problem occurs when a large-size sheet is conveyed in the conveyance apparatus of the sheet post-processing apparatus according to the present invention. FIG. 10 is a diagram illustrating an operation example when a large-size sheet is conveyed by the conveyance device of the sheet post-processing apparatus according to the present invention. It is a figure which shows the structural example of the control system of a paper post-processing apparatus.

Explanation of symbols

1: Inlet roller 2, 3: Conveying roller (conveying means upstream of switching means)
4: Rotation guide 5, 6: Conveying roller (conveying means downstream of the switching means)
7: Stipple conveyance roller 8: Tapping roller 9: Switching claw (switching means)
10 (10a, 10b): Release claw 11: Processing tray (stipple processing tray)
12: Stippler 13: Rear end fence 14: Ejection belt 17: Alignment fence 19: Punch unit 22: Ejection roller 23: Ejection tray 100: Image forming apparatus 100A: Image forming apparatus main body side control unit 200: Paper post-processing Device 300: Control device A2, A3: Main transport path (A2: Main transport path upstream side, A3: Main transport path downstream side)
A4: Conveyance path for staying P: Paper P1: Previous paper P2: Next paper SN1: Entrance sensor (detection means)
SN2: paper sensor (detection means)

Claims (10)

An incoming paper sheet received from the preceding apparatus, the sheet transport apparatus for transporting the processing tray for postprocessing,
A main transport path for guiding the sheet to the processing tray, and the second conveying unit first conveying means for transporting before Symbol processing tray the sheets provided in the main conveyance path, branched from the main transport path And a retention conveyance path for temporarily retaining the paper,
The second conveying means and the processing tray the paper conveyed in the reverse direction (hereinafter, regurgitation and referred) and that capable of constituting, the paper when said main transport path is flowing back the paper And a switching means for guiding to the stay conveyance path,
The first conveying means is provided on the upstream side of the switching means, and the second conveying means is provided on the processing tray side of the switching means,
The preceding sheet is retained in the retention conveyance path while being held by the second conveyance unit, and the leading edge of the next sheet is positioned between the main conveyance path switching unit and the second conveyance unit by the first conveyance unit. The second transport unit is activated when transported to the processing tray, and the second transport unit transports the preceding paper and the next paper toward the processing tray in a state of being overlapped. apparatus. In the paper conveyance device according to claim 1,
Preceding paper is distilled stagnation the residence conveyance path while being held by the second transport means, the leading edge of the following sheet of the second conveying means and switching means of the main conveying path by the first conveying means when it is transported between the conveying speed when the sheet reaches the second conveying means, the sheet conveying apparatus characterized by slower than the conveying speed of the first conveying means. In the paper conveyance device according to claim 1 or 2,
Preceding paper is distilled stagnation the residence conveyance path while being held by the second transport means, the leading edge of the following sheet of the second conveying means and switching means of the main conveying path by the first conveying means when it is transported between the conveying speed of the second conveying means, the next sheet is conveying speed and same speed of the first conveying means from a little from being conveyed to the second conveying means A sheet conveying apparatus characterized by the above. In the paper conveyance device according to any one of claims 1 to 3,
2. A sheet transporting apparatus according to claim 1, wherein when there is no sheet in the staying transport path, the start timing of the second transport unit is set to the same timing as the start timing of the first transport unit . In the paper conveying apparatus as described in any one of Claims 1-4,
In the case of a paper size that is not transported to the staying transport path, the start timing of the second transport means is set to the same timing as the start timing of the first transport means. In the paper conveyance device according to any one of claims 1 to 5,
In the case of a paper sheet thickness that is not transported to the staying transport path, the start timing of the second transport means is set to the same timing as the start timing of the first transport means. In the paper conveyance device according to any one of claims 1 to 6,
In the case of a paper type that is not transported to the staying transport path, the start timing of the second transport means is set to the same timing as the start timing of the first transport means. In a paper post-processing apparatus having a function of post-processing an image-formed paper ,
A paper transport device according to any one of claims 1 to 7, a processing tray that is located downstream of a main transport path of the paper transport device and that performs post-processing of the paper, and a paper processed by the processing tray Equipped with a paper output tray
In the processing tray, an alignment unit that stacks and aligns the sheets conveyed through the main conveyance path, a binding unit that binds the aligned sheet bundle, and a sheet bundle bound by the binding unit are discharged. A sheet post-processing apparatus having discharge means for discharging to a tray . An image forming apparatus comprising the sheet conveying device according to claim 1 . An image forming apparatus comprising the sheet post-processing apparatus according to claim 8 .

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