JP2010111454A - Paper superimposing section - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To distinguish invalid papers generated in an image forming device from effective papers, and smoothly discharge the invalid paper without requiring complicated control, at a paper superimposing section interposed between an image forming section and a post-processing section carrying out the post-processing of papers. <P>SOLUTION: The paper superimposing section includes a stand-by section receiving the papers carried from the image forming section one by one, and superimposing the plurality of the papers to discharge toward the post-processing section; a bypass section discharging the papers carried from the image forming section one by one toward the post-processing section without passing through the stand-by section; and a controlling section selecting the carrying direction of the papers from the stand-by section and the bypass section. When the invalid paper is discharged from the image forming section, the controlling section decides whether the invalid paper is discharged after discharging the effective papers on standby according to predetermined conditions when the effective papers on standby are in the stand-by sectopm or the effective papers in the stand-by section are discharged after discharging the invalid paper through the bypass section. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention conveys sheet by sheet from the image forming section interposed between an image forming section that forms an image based on image data and a post-processing section that performs post-processing of the paper on which the image has been formed. The present invention relates to a sheet superimposing unit that receives the sheets to be printed and superimposes a plurality of sheets and discharges them to the post-processing unit.

In an image forming apparatus that forms an image on paper at high speed based on image data, post-processing apparatuses having various post-processing functions are connected to meet a wide range of user needs. Post-processing functions provided in the post-processing apparatus include a punching processing function, a binding processing function, a folding processing function, and the like, and post-processing machines having a plurality of post-processing functions are also provided.
The image forming speed has been increased more and more with the improvement of functions. On the other hand, the post-processing apparatus often pauses the paper to perform the post-processing function, and there is a limit to improving the processing speed. There is. For this reason, a post-processing apparatus with low productivity is often connected to an image forming unit with high productivity, which causes a problem that the productivity of the image forming unit cannot be maintained. In order to solve such a problem, a paper superimposing unit is interposed between the image forming unit and the post-processing device, and the paper discharged from the image forming unit is superposed on the paper superimposing unit and conveyed to the post-processing device. Has been proposed that can maintain the productivity of the image forming unit (see Patent Document 1).

By the way, in an image forming part, image formation is not performed satisfactorily for various reasons, and there are cases where an image cannot be used as printed matter. Such paper must be excluded from the valid paper as invalid paper. For example, Patent Document 2 describes that when a double feed of paper is detected, the paper is transported to a location different from a set paper discharge destination (paper discharge destination to which valid paper is discharged) (paragraph 0058). In addition, the paper superimposing unit disclosed in Patent Document 1 has a bypass unit that can discharge paper without passing through the standby unit, in addition to the standby unit that waits and superimposes the paper. When invalid paper is detected, it is possible to discharge invalid paper through the bypass unit without passing through the standby unit in which valid paper on which image formation has been appropriately performed is waiting.
JP 2008-110510 A JP 2006-160484 A

  As described above, in the paper superimposing unit, when invalid paper is discharged from the image forming unit, if there is valid paper waiting in the standby unit of the paper superimposing unit, the valid paper and invalid paper are used in order to utilize the valid paper. It is necessary to discharge without overlapping. For this reason, it is conceivable that the invalid paper is discharged through the bypass portion disclosed in Patent Document 1. However, the paper superimposing unit is located between the image forming unit and the post-processing unit, and maintains the productivity of the image forming unit by performing superimposing when the productivity of the post-processing unit is lower than the productivity of the image forming unit. This is provided for the purpose of printing, and when the output of the image forming unit is maintained on the assumption that the sheets are stacked and transported to the post-processing unit, the post-processing is performed when the sheets are discharged without being stacked. The interval with the succeeding paper in the section is not sufficient. In the post-processing unit, in order to perform necessary post-processing, it is necessary that a predetermined interval is secured between the sheets. If this interval is not secured, the post-processing itself becomes difficult or the post-processing unit Paper jam will occur. In addition, if it is found that what is supposed to be overlapped is not overlapped immediately before the overlap portion, there is a possibility that a paper jam occurs in the overlap portion. In order to avoid these problems, it is necessary to delay the receipt or discharge of the overlapping portion of the succeeding sheets discharged without overlapping.

  However, in any case, complex control that takes into account many conditions such as paper size, transport path length, image forming unit productivity, post-processing unit productivity, transport speed, and timing when it was determined that they will not overlap. Need. Furthermore, when a plurality of papers discharged without being stacked are continuous, it is not possible to delay the reception / discharge of the overlapping part. In this case, the valid paper and the invalid paper must be stacked, and the valid paper is wasted. In addition, it may be possible to temporarily reduce the productivity of the image forming unit, but it is necessary to know in advance that it will not overlap in order to reduce the productivity. You can't lose sex.

  The present invention has been made against the background of the above circumstances, and when invalid paper is generated in the image forming unit, the valid paper and the invalid paper are not overlapped, and the interval in the post-processing unit is sufficiently maintained to be invalid. An object of the present invention is to provide a paper superimposing unit capable of discharging paper.

In other words, the sheet superimposing unit of the first aspect of the present invention is interposed between an image forming unit that forms an image based on image data and a post-processing unit that performs post-processing of the sheet on which the image has been formed. A paper stacking unit,
A standby unit that receives sheets conveyed one by one from the image forming unit, superimposes a plurality of sheets, and discharges them to the post-processing unit; and a sheet that is conveyed one by one from the image forming unit A bypass unit that discharges toward the post-processing unit without going through, and a control unit that selects one of the standby unit and the bypass unit as a conveyance direction of a sheet conveyed from the image forming unit, When invalid paper is discharged from the image forming unit, the control unit discharges the invalid paper after waiting the valid paper according to a predetermined condition when there is valid paper waiting in the standby unit. It is determined whether to discharge or to discharge the invalid paper first through the bypass unit and then to discharge the valid paper in the standby unit.

  In the first aspect of the present invention, the sheet superimposing unit according to the second aspect of the present invention is configured such that, when the invalid paper is discharged from the image forming unit, the control unit and If the interval with the invalid paper is equal to or greater than the interval necessary for receiving the paper in the post-processing unit, the invalid paper is discharged toward the post-processing unit after discharging the valid paper in the standby unit, and the interval Is smaller than the necessary interval, the invalid paper is discharged first through the bypass unit, and then the valid paper in the standby unit is discharged.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the control unit waits in the standby unit after discharging the invalid paper through the bypass unit. When discharging the valid paper, the valid paper in the standby unit and the valid paper transported next to the invalid paper are overlapped in the standby unit and then discharged.

  According to a fourth aspect of the present invention, in the first or second aspect of the present invention, when the control unit discharges the invalid paper after discharging the valid paper in the standby unit, the invalid paper is used. Is discharged via the standby unit.

  The paper superimposing unit according to a fifth aspect of the present invention is the paper superposing unit according to any one of the first to fourth aspects of the present invention, wherein the control unit waits for the invalid paper when the standby paper is not in the standby unit. It is characterized by discharging via the part.

  According to a sixth aspect of the present invention, in the fourth or fifth aspect of the present invention, when the control unit discharges the invalid paper via the standby unit, a plurality of invalid papers are continued. In some cases, the invalid sheets are overlapped by the standby unit and then discharged.

  In the sixth aspect of the present invention, the sheet superimposing unit according to the seventh aspect of the present invention is configured such that when the invalid paper reaches the predetermined number when the control unit superimposes the invalid paper on the standby unit, It is characterized by performing.

  In the fourth to seventh aspects of the present invention, the sheet superimposing unit according to the eighth aspect of the present invention is configured such that when the control unit discharges the invalid sheet via the standby unit, the valid sheet is conveyed next to the invalid sheet. In this case, after the invalid paper is discharged, the standby section waits for the valid paper.

  According to the paper superimposing unit of the present invention, the paper superposition interposed between the image forming unit that performs image formation based on the image data and the post-processing unit that performs post-processing of the paper on which the image has been formed. A standby unit that receives sheets conveyed one by one from the image forming unit, superimposes a plurality of sheets, and discharges the sheets toward the post-processing unit, and is conveyed one by one from the image forming unit A bypass unit that discharges the sheet toward the post-processing unit without passing through the standby unit, and a control unit that selects a conveyance direction of the sheet conveyed from the image forming unit as either the standby unit or the bypass unit And when the invalid paper is discharged from the image forming unit, the control unit discharges the standby valid paper according to a predetermined condition when there is standby standby paper in the standby unit. The invalid paper is discharged from the front or Since it is determined whether the invalid paper is discharged first through the bypass unit and then the valid paper in the standby unit is discharged, even if there is valid paper in the standby unit, complicated control is not required. Paper can be discharged without overlapping invalid paper and valid paper, and a paper interval in the post-processing section can be secured. Further, according to the above, there is an effect that all the valid sheets before and after the invalid paper can be utilized.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a diagram illustrating an outline of a mechanical configuration of an image forming system including a sheet superimposing unit according to the present invention.
The image forming system includes an image forming apparatus A having an image forming unit 4, a paper superimposing unit B, and a paper post-processing unit C. Hereinafter, each device and each unit will be described in detail.

<Image forming apparatus>
As shown in FIG. 1, the image forming apparatus A includes an automatic document feeder DF and a large-capacity paper feeder LT, and an image reading unit 1, an image control unit 2, a paper supply unit 3, an image forming unit 4, and a paper It has a discharge unit 5, a storage unit 6, and a communication unit 9.

The image forming unit 4 includes a photosensitive drum 4A, a charging unit 4B, a developing unit 4C, a transfer unit 4D, a separating unit 4E, a cleaning unit 4F, an image writing unit 4G, a fixing device 4H, and the like.
The paper supply unit 3 includes a paper feed cassette 3A, a first paper feed unit 3B, a second paper feed unit 3C, a transport unit 3D, and a paper on which an image is formed on the front surface in the back side image formation during double-sided image formation. 4 includes a paper refeeding unit (ADU) 3F that re-feeds the paper and further includes a paper discharge unit 5 that discharges the paper conveyed from the image forming unit 4.
An operation display unit 8 including an input unit and a display unit is disposed on the upper front side of the image forming apparatus main body A.

The document placed on the document table of the automatic document feeder DF is scanned on one or both sides of the document by the optical system of the image reading unit 1, and the photoelectrically converted analog signal is analog processed in the image control unit 2. Then, after processing such as A / D conversion, shading correction, and image compression processing, it is sent to the image writing unit 3. The image control unit 2 controls the entire image forming apparatus A, and includes a CPU and a program for operating the CPU.
In the image writing unit 4G, output light from the semiconductor laser is irradiated onto the photosensitive drum 4A to form a latent image. In the image forming unit 4, processes such as charging, exposure, development, transfer, separation, cleaning, and fixing are performed.

  The paper S fed by the first paper feed unit 3B is transferred to the paper S by the transfer unit 4D. The sheet S carrying the image is fixed by the fixing device 4H and sent from the sheet discharge unit 5 to the sheet superimposing unit B. Alternatively, the single-sided image processed paper S sent to the refeed unit 3F is again subjected to double-sided image processing in the image forming unit 4 and then discharged from the paper discharge unit 5 and sent to the paper superimposing unit B.

  Note that invalid paper is detected by the invalid paper detection unit 7 for the paper conveyed to the paper discharge unit 5. The detection result of the invalid paper detection unit 7 is transmitted to the image control unit 2, and it is determined whether the paper is invalid paper or valid paper based on the detection result. The invalid paper in the present invention is paper that has failed to form an image, and is distinguished from valid paper that has been appropriately formed. Examples of invalid paper include paper on which image formation itself has not been performed, and paper on which image formation has been performed, but image formation is poor or likely to be defective.

The configuration and arrangement position of the invalid paper detection unit 7 differ depending on the detection method. For example, when detecting a paper curl or the like on the conveyance path to the image forming unit 4, the paper curl is detected on the upstream side of the image forming unit 4, and the image control unit 2 detects the paper curving to be a predetermined amount or more. The paper is determined to be invalid. In addition to this, when the speed of the transfer belt provided in the transfer unit 4D is measured by the invalid paper detection unit 7 and the image control unit 2 determines that speed unevenness has occurred, the transfer unit 4D passes through the transfer unit 4D. Thus, the paper on which the image has been formed can be determined as invalid paper. In addition to this, when the temperature in the fixing device 4H is measured by the invalid paper detection unit 7 and the measured temperature is outside the predetermined range by the image control unit 2, the paper fixed by the fixing device 4H is invalid paper. Can be determined.
Note that the determination criterion as to whether or not the paper is invalid can be stored in the nonvolatile storage unit 6, and the determination can be performed by reading the determination criterion data by the image control unit 2.

  The paper discharge section 5 is a straight discharge path SH that horizontally conveys and discharges the paper S discharged from the fixing device 4H, and a reverse discharge that discharges the paper S discharged from the fixing device 4H by turning it upside down. Has a paper path HH. The reverse paper discharge path HH includes a paper introduction section of the paper refeed section 3F and a transport path that switches back from the paper refeed section 3F to the paper discharge section 5.

The large-capacity paper feeding device LT includes a paper stacking unit 3G, a first paper feeding unit 3H, and the like, and continuously feeds a large amount of paper S to the image forming apparatus A.
Note that a large-capacity paper feeder LT is connected to a paper superimposing unit B, which will be described later, so that a large amount of printed paper S accommodated in the large-capacity paper feeder LT is directly fed to the paper superimposing unit B. Also good.

  On the left side of the image forming apparatus A shown in the figure, a paper stacking unit B is connected to the paper discharge unit 5 side. The image forming apparatus A and the paper superimposing unit B are capable of bidirectional communication by the communication unit 9 provided in the image forming apparatus A and the pre-stage communication unit 101 provided in the paper superimposing unit B. The upstream communication unit 101 is notified of operation start, operation stop, discharge of paper (invalid paper and valid paper), invalid paper detection, and the like.

<Paper stacking section>
As shown in FIGS. 1 to 3, the sheet superimposing unit B horizontally arranges the sheet receiving unit B <b> 0 that receives the sheet S discharged from the image forming apparatus A, the standby unit B <b> 1 that accumulates a plurality of sheets, and the sheet S. Bidirectional communication is performed with the conveying bypass unit B2, the sheet discharge unit B3 that discharges the sheet S to the post-processing apparatus C, the control unit 100 that controls the entire sheet superimposing unit B, and the communication unit 9 of the image forming apparatus A. Between the pre-stage communication unit 101, the storage unit 102 that can store data, the standby unit sheet detection unit 103 that detects the standby sheet in the standby unit B1, and the communication unit 201 of the sheet post-processing unit C described later. A rear communication unit 104 that performs bidirectional communication is provided. The control unit 100 includes a CPU and a program for operating the CPU.

  As shown in FIG. 2, the paper receiving portion B0 is formed by a pair of upper and lower guide plates 111, and the standby portion B1 includes a pair of guide plates 131 that guide the paper S from the paper receiving portion B0 obliquely downward, and the paper S. A pair of vertical guide plates 121 and a pair of guide plates 132 that guide the paper S to the upper left are formed. The bypass portion B2 is formed by a pair of horizontal guide plates 141 that are arranged vertically and discharged. The part B3 is formed by a pair of guide plates 134 arranged vertically.

  Reference numeral 113 denotes a switching gate which is set to a solid line position 113A and a dotted line position 113B, and switches the conveyance path to the standby unit B1 or the bypass unit B2, and rotates around the shaft 113C under the control of the control unit 100. Switch the transport path. Reference numeral 133 denotes an alignment member that aligns the upper ends of the sheets S, and is set by rotating around a shaft 133C between a solid line position 133A and a dotted line position 133B. When the leading edge faces the conveyance path at the position of the solid line 133A, the aligning member 133 aligns the sheet, retreats to the position of the dotted line, and the sheet S can advance to the upper left. Note that the upper portion of the standby unit B1, the bypass unit B2, and the paper discharge unit B3 are shown in an enlarged manner in FIG.

A conveyance roller R1 including a pair of rollers is provided in the sheet receiving unit B0, conveyance rollers R2 and R3 and a driven roller R4 are provided in the standby unit B1, and a discharge roller R5 including a pair of rollers is provided in the sheet discharge unit B3.
As shown in FIG. 3, the driven roller R4 is displaced between the position of the solid line and the position of the dotted line, and the transport roller R2 is pressed against the driven roller R4 by the spring 135, and the position of the solid line is changed according to the displacement of the driven roller R4. It is displaced with the position of the dotted line (see FIG. 3). The pair of left and right width alignment plates 122 are driven by a motor (not shown) and perform sheet alignment in the width direction perpendicular to the transport direction.

The operation of the paper superimposing unit B will be described. The switching gate 113 is normally set at the position 113A, and the transport roller R2 and the driven roller R4 are at the solid line positions in FIG. The first sheet S1 that is nipped and conveyed by conveyance rollers R1 and R2 that rotate at the same linear speed as the sheet discharge roller of the sheet discharge unit 5 of the image forming apparatus A is guided to the standby unit B1 by the switching gate 113. And proceed downwards. The leading edge (lower end) of the first sheet S conveyed to the standby unit B1 comes into contact with the horizontal stopper 123A of the support member 123 and stops. This sheet is detected by the in-standby sheet detection unit 103. When the paper is deposited, a stopper 123A of the support member 123 is moved to a first position above a predetermined distance by a motor (not shown).
The second sheet S is transported by transport rollers R1 and R2 and transported to standby unit B1. When the second sheet S is carried in, the upper end of the first sheet S is raised by the raising of the support member 123, so that collision between the sheets S and S is prevented. The lower end of the second sheet S reaches the stopper 123A, and the two sheets S and S are collected in the standby unit B1. At this time, the support member 123 is lowered from the first position to the initial position. Further, the driven roller R4 moves to the right, and a gap is formed between the transport roller R3 and the driven roller R4. The transport roller R3 is pushed by the driven roller R4 and moves to the right.

  When the support member 123 is driven by a motor (not shown), the support member 123 moves from the initial position to a second position that is a predetermined distance above the initial position. After abutting and stopping at 133, vertical alignment, that is, vertical alignment in the transport direction is performed. The upper end stop position of the two sheets S, S that are vertically aligned is downstream (upward) in the transport direction from the transport roller R3. At the same time as or after completion of the vertical alignment, the width alignment plate 122 is driven by a motor (not shown) to press the side edges in the width direction of the sheets S and S to perform horizontal alignment, that is, alignment in the width direction.

The driven roller R4 moves to the left and comes into pressure contact with the conveying roller R3, and the sheets S and S are sandwiched between the conveying roller R3 and the driven roller R4. The transport roller R2 moves to the left following the driven roller R4. As a result, the next sheet can be introduced into the standby unit B1.
The support member 123 lowers the position of the stopper 123A to the initial position and returns to the original position, and the alignment member 133 is displaced to the retracted position, thereby allowing the sheet to pass. With the alignment member 133 retracted, the transport rollers R3 and R5 rotate to discharge the sheets S and S.
Further, simultaneously with the discharge of the sheets S and S, the third sheet S is transported by the transport rollers R1 and R2 and carried into the standby unit B1.
When the discharge of the sheets S, S is completed, the alignment member 133 returns to the position indicated by the solid line in FIG.
In this example, it is described that two sheets are superposed and discharged by the standby unit, but the number of superposed sheets is not limited in the present invention. The number of superimposed sheets is stored in, for example, the storage unit 102 and read by the sheet superimposing unit 100, so that a predetermined number of sheets can be superimposed and discharged.

When the paper is transported using the bypass unit B2 without using the standby unit B1, the switching gate 113 moves to a position indicated by 113B in FIG. 3 to guide the paper S to the bypass unit B2.
In the transport mode in which the paper S is transported to the standby unit B1 and discharged, it is possible to discharge the paper S one by one without stacking the paper S. Alternatively, three or more sheets can be stacked and discharged. Is possible.
A post-processing unit C is connected to the sheet discharge unit B3 side on the left side of the sheet stacking unit B in the drawing.
In this embodiment, the paper superimposing unit B is described as being independent of the image forming apparatus A, but the paper superimposing unit may be included in the image forming apparatus.

<Post-processing section>
Hereinafter, the sheet post-processing section C will be described.
Examples of the post-processing unit include a punching and folding machine, a flat stitching machine, a saddle stitching machine, and a case binding machine, but the present invention is not limited to those intended for specific post-processing.
The paper post-processing unit C is sent from the paper receiving unit C0 that receives the paper discharged from the paper superimposing unit B, the paper transporting unit C1 that transports the paper introduced into the paper receiving unit C0, and the paper transporting unit C1. A post-processing unit C3 that performs predetermined post-processing on a plurality of sheets, a sheet discharge unit C4 that discharges the sheet S, a post-processing control unit 200 that controls the entire sheet post-processing unit C, and a subsequent stage of the sheet superimposing unit B A communication unit 201 that performs bidirectional communication with the communication unit 104 and a storage unit 202 that can store data are provided. The post-processing control unit 200 includes a CPU and a program for operating the CPU.

  The paper discharge section C4 includes a main tray 205 and a sub-tray 206. The paper transport section C1 transports the paper transported from the paper receiving section C0 to the post-processing section C3. A path 203 and a transport path 204 for transporting the sheet transported from the sheet receiving unit C0 to the sub-tray are provided. Selection of the transport paths 203 and 204 is performed by the post-processing control unit 200.

  That is, when the post-processing control unit 200 receives a notification of valid paper discharge from the control unit 100 of the paper superimposing unit B through communication between the post-communication unit 104 and the communication unit 201 of the paper superimposing unit B, the paper transporting unit In section C1, the transport path 203 is selected, and the sheet is transported to the post-processing section C3 to perform necessary post-processing. The post-processed paper is discharged to the main tray 205 in the paper discharge unit C4. Further, upon receiving a notification of invalid paper discharge from the control unit 100 of the paper superposition unit B through communication between the post-communication unit 104 and the communication unit 201 of the paper superposition unit B, the post-processing control unit 200 The transport path 204 is selected in the transport section C1, and the paper is discharged to the sub-tray 206 in the paper discharge section C4 without performing post-processing. Further, the sub-tray 206 can be a discharge destination for discharging valid paper that does not require post-processing.

Next, FIG. 4 is a block diagram of a control system for controlling the sheet conveyance and the like of the image forming system.
In the image forming apparatus A, the entire image forming apparatus is controlled by the image control unit 2. The image control unit 2 includes the paper supply unit 3, the image forming unit 4, the paper discharge unit 5, the storage unit 6, and invalid paper. The detection part 7, the operation display part 8, and the communication part 9 are connected so that control is possible. The detection result of the invalid paper detection unit 7 is transmitted to the image control unit 2 as described above, and the image control unit 2 reads the determination reference data stored in the storage unit 6 and based on the reference data. Thus, the valid paper and invalid paper are determined. Under the control of the image control unit 2, the paper is discharged from the paper discharge unit 5 to the paper receiving unit B 0 of the paper superimposing unit B. Further, the image control unit 2 notifies the upstream communication unit 101 of the paper superimposing unit through the communication unit 9 of operation start, operation stop, paper discharge, valid paper, invalid paper, and the like.

  In the paper superimposing unit B, the control unit 100 controls the entire paper superimposing unit. The control unit 100 includes a paper receiving unit B0, a standby unit B1, a bypass unit B2, a paper discharging unit B3, and a pre-stage communication unit. 101, a storage unit 102, a standby-unit paper detection unit 103, and a rear communication unit 104 are connected to be controllable.

  In the control unit 100, the standby unit B1 and the bypass unit B2 can be selected on the downstream side of the sheet receiving unit B0, and when valid paper is conveyed from the image forming apparatus A, the control unit 100 displays the sheet receiving unit. Control is performed to convey the valid sheet from B0 to the standby unit B1. On the other hand, when invalid paper is transported from the image forming apparatus A, the control unit 100 performs control to transport and wait to the standby unit B1 if there is no valid paper in the standby unit B1. By conveying the invalid paper to the standby unit B1, the interval between the sheets can be maintained regardless of the valid paper or the invalid paper.

  In the control unit 100, the storage unit 102 stores information indicating that invalid paper is waiting in the standby unit B1 and the number of sheets. The control unit 100 discharges invalid paper from the standby unit B1 toward the post-processing unit C when the standby number of invalid paper in the standby unit B1 reaches a predetermined number. The predetermined number of pieces of data is stored in the storage unit 102, and the control unit 100 reads out the data and controls the discharge of invalid paper. The predetermined number may be one or two or more. When invalid paper is waiting in the standby unit B1, if the succeeding paper is valid paper, the control unit 100 discharges the invalid paper from the standby unit B1, and then makes the standby paper wait in the standby unit B1.

  When the invalid paper is conveyed from the image forming apparatus A, if the valid paper is waiting in the standby unit B1, the control unit 100 determines whether the valid paper discharged from the standby unit B1 and the subsequent invalid paper are used. It is determined whether the interval is sufficient. The determination criterion for the interval is stored in the storage unit 102, and the determination is performed based on the determination criterion. Note that the determination criterion is set based on whether or not the interval is sufficient (or necessary) for proper post-processing in the downstream sheet post-processing section C, and the sheet is smaller than the determination criterion. If the paper is conveyed to the paper post-processing section C, there is a possibility that the post-processing may not be properly performed or a paper jam may occur. If the interval is sufficient according to the above determination, the valid paper in the standby unit B1 is discharged first. If the interval is insufficient, the invalid paper is discharged first via the bypass unit B2.

  The control unit 100 notifies the sheet post-processing unit C of the sheet superimposing unit B whether the paper is discharged, whether it is valid paper, or invalid paper, via the post-stage communication unit 104 and the communication unit 201 of the paper post-processing unit C. . The paper discharged from the paper superimposing unit B is conveyed from the paper discharging unit B3 to the paper receiving unit C0 of the paper post-processing unit C.

  In the sheet post-processing section C, the entire post-processing section is controlled by the post-processing control section 200. The post-processing control section 200 includes a sheet receiving section C0, a sheet transport section C1, a post-processing section C3, and a sheet discharge section C4. The communication unit 201 and the storage unit 202 are connected to be controllable. When the post-processing control unit 200 receives an invalid paper detection notification from the paper superimposing unit B in accordance with the process parameters stored in the storage unit 202, the post-processing control unit 200 moves the conveyance path 204 in the paper conveyance unit C1. Then, the invalid paper is discharged to the sub-tray 206. Further, when receiving the discharge notification without receiving the valid paper discharge notification or the invalid paper detection notification, the post-processing control unit 200 selects the transport path 203 in the paper transport unit C1, and outputs the valid paper to the post-processing unit. The sheet is conveyed to C3, and predetermined post-processing is performed on a plurality of sheets. The post-processed paper is discharged to the main tray 205.

Next, the paper transport procedure in the paper superimposing unit B will be described based on the flowcharts of FIGS.
With the start of processing, it is determined whether or not there is an operation stop notification from the image forming apparatus as the start of routine 1 (step s1). If there is an operation stop notification (YES in step s1), the routine proceeds to routine 3. On the other hand, if there is no operation stop notification (step s1, NO), it is determined whether there is an invalid paper detection notification from the image forming apparatus A (step s2). If there is no such notification (step s2, NO), the process proceeds to step 2.

  If there is an invalid paper detection notification (step s2, YES), it is determined whether there is valid paper in the standby section (step s3). If there is valid paper in the standby unit (step s3, YES), it is determined whether or not the interval between the valid paper and the invalid paper on standby is sufficient (step s4). If there is no valid paper in the standby section (step s3, NO), the process proceeds to step s6. If the interval at step s4 is not sufficient (step s4, NO), the printer waits for an invalid paper discharge notification from the image forming apparatus (step s12), and discharges the invalid paper via the bypass unit (step s13). Move to 2.

  When it is determined in the determination in step s4 that the interval between the valid paper and the invalid paper that is on standby is sufficient (step s4, YES), the standby valid paper is discharged by the standby unit (step s5), and the image is displayed. It waits for an invalid paper discharge notification from the forming apparatus (step s6). When there is an invalid paper discharge notification, it is determined whether there is invalid paper in the standby unit (step s7). If there is no invalid paper in the standby unit (step s7, NO), the invalid paper is waited in the standby unit. (Step s8), the process returns to the beginning of routine 1. On the other hand, if there is invalid paper in the standby part (step s7, YES), it is determined whether or not the number of invalid paper and the subsequent invalid paper in the standby part has reached a predetermined number (step s9). If the predetermined number of sheets has not been reached, the subsequent invalid paper is placed on standby with the invalid paper in the standby section (step s11), and the routine returns to the beginning of routine 1. If the predetermined number of invalid papers in the standby unit and the invalid paper being conveyed has reached the predetermined number (step s9, YES), the subsequent invalid paper is received in the standby unit and becomes the invalid paper in the standby unit that has been waiting first. Overlay and discharge. Note that it is possible to appropriately set how many sheets of invalid paper are to be discharged, and the predetermined number can be stored in the storage unit 102 and read by the control unit 100 to make the above determination. Note that the predetermined number of sheets may be one. In this case, invalid paper can be received and discharged into the standby unit without going through step s7, and the routine 1 can be returned to the beginning.

  Next, in the routine 2, as shown in FIG. 6, first, it is determined whether or not there is a notice of valid paper discharge from the image forming apparatus (step s20). If there is no such notification (step s20, NO), the routine returns to the beginning of routine 1. If there is such notification (step s20, YES), it is determined whether there is valid paper in the standby section (step s21). If there is valid paper in the standby part (step s21, YES), the subsequent valid paper is superposed and discharged in the standby part (step s22), and the routine returns to the beginning of routine 1. If there is no valid paper in the standby section in the above determination (step s21, NO), it is determined whether there is invalid paper in the standby section (step s23). If there is no invalid paper in the standby unit (step s23, NO), the standby unit accepts the subsequent valid paper in the standby unit (step s24) and returns to the beginning of routine 1. On the other hand, if there is invalid paper in the standby section (step s23, YES), after the invalid paper in the standby section is discharged (step 25), the standby section accepts the valid paper and waits (step s24). Return to the beginning.

Next, in the routine 3, as shown in FIG. 7, it is determined whether or not there is invalid paper or valid paper in the standby unit (step s30). If there is no sheet in the standby unit (step s30, NO), the process is terminated. On the other hand, when there is invalid paper or valid paper in the standby unit (step s30, YES), the paper in the standby unit is discharged (step s31), and then the process ends.
By repeating the above procedure, the valid paper and invalid paper discharged from the image forming apparatus can be smoothly discharged to the post-processing unit without impairing the productivity of the image forming apparatus.

  Next, a specific example of paper conveyance in the paper superimposing unit will be described with reference to the ladder diagrams of FIGS. In this example, a case where valid sheets are discharged from the first to third sheets and the fourth sheet is invalid paper will be described. In the image forming apparatus, the operation is stopped when invalid paper is detected.

First, when an operation start notification is sent from the image forming apparatus to the paper superimposing unit, the notification is further sent to the paper post-processing unit by the paper superimposing unit.
When the first effective sheet is discharged from the image forming apparatus, a discharge notification is sent to the sheet superposition unit. At this time, since the invalid paper detection notification is not made, the control unit of the paper superimposing unit determines that the paper is valid paper and accepts the conveyed valid paper into the standby unit.

Further, when the second effective sheet is discharged from the image forming apparatus, a discharge notification is sent to the sheet superposition unit. The control unit accepts the conveyed effective paper in the standby unit and superimposes it on the first effective paper, and then issues a discharge notification to the paper post-processing unit and discharges the paper. In this example, the sheet is set to be discharged when two sheets are superimposed on the standby unit.
Further, when the third effective sheet is discharged from the image forming apparatus, a discharge notification is sent to the sheet superposition unit. The control unit receives the conveyed effective paper in the standby unit and waits.

  Next, when an invalid paper detection notification is made from the image forming apparatus, the control unit determines whether the interval between the third valid paper in the standby unit and the invalid paper conveyed later is sufficient. I do. This interval can be determined by the interval between the invalid paper detection notification and the valid paper discharge notification. If it is determined in this determination that the interval is sufficient, as shown in FIG. 8, the third effective sheet in the standby unit is discharged first. The paper post-processing unit receives the discharge notification from the paper superimposing unit and determines that the paper is valid, thereby conveying the conveyed valid paper to the post-processing unit.

An invalid paper discharge notification is further issued from the image forming apparatus, and the invalid paper is discharged. The control unit causes the conveyed invalid paper to wait in the standby unit where the valid paper has already been discharged. Thereafter, the image forming apparatus sends an operation stop notification to the paper superimposing unit in association with the detection of the invalid paper, and then stops the operation. In accordance with this, the paper superimposing unit discharges the invalid paper in the standby unit to the paper post-processing unit, further performs an operation stop notification to the paper post-processing unit, and stops the operation.
In accordance with the notification, the paper post-processing unit stops the operation after discharging invalid paper to the sub-tray.

  On the other hand, in the above operation, when the fourth sheet is invalid paper and the detection notification is given to the sheet superimposing unit, the control unit of the sheet superimposing unit controls the third valid sheet in the standby unit. The case where it is determined that the interval between the invalid paper conveyed later and the invalid paper is insufficient is described with reference to FIG. Since the previous procedure is the same as that shown in FIG.

  When the control unit of the paper superimposing unit determines that the interval is insufficient, the paper post-processing unit issues an invalid paper discharge notification to the paper post-processing unit in accordance with the invalid paper discharge notification and invalid paper discharge from the image forming apparatus, The fourth invalid paper is first discharged to the paper post-processing section through the bypass section. The paper post-processing unit discharges invalid paper to the sub-tray according to the notification.

Thereafter, when the operation of the image forming apparatus is stopped along with the detection of invalid paper in the image forming apparatus, an operation stop notification is sent to the paper superimposing unit. In accordance with this, the paper superimposing unit notifies the paper post-processing unit of the discharge of the valid paper in the standby unit and discharges it toward the paper post-processing unit. Further, the paper superimposing unit then sends it to the paper post-processing unit. Stop operation by sending an operation stop notification.
In accordance with the notification, the paper post-processing unit conveys the valid paper to the post-processing unit and stops operation.

  As mentioned above, although this invention was demonstrated based on the said embodiment, this invention is not limited to description of the said embodiment, A suitable change is possible unless it deviates from the scope of the present invention.

1 is a mechanical schematic diagram illustrating an image forming system including a sheet superposition unit according to an embodiment of the present invention. Similarly, it is an enlarged view of a paper overlapping portion. Similarly, it is an enlarged view of the upper part of the standby part B1, the bypass part B2, and the paper discharge part B3 in the paper superposition part. Similarly, it is a control block diagram of an image forming system. Similarly, it is a flowchart which shows the conveyance control procedure in a paper superimposition part. Similarly, it is a flowchart which shows the conveyance control procedure in a paper superimposition part. Similarly, it is a flowchart which shows the conveyance control procedure in a paper superimposition part. Similarly, it is a ladder diagram showing the sheet conveying operation of the image forming system. Similarly, it is a ladder diagram showing the sheet conveying operation of the image forming system.

Explanation of symbols

A Image forming apparatus B Paper stacking unit B1 Standby unit B2 Bypass unit B3 Paper discharge unit C Paper post-processing unit C0 Paper receiving unit C3 Post-processing unit 2 Image control unit 4 Image forming unit 5 Paper discharge unit 100 Control unit

Claims (8)

A paper superimposing unit interposed between an image forming unit that performs image formation based on image data and a post-processing unit that performs post-processing of the paper on which the image has been formed;
A standby unit that receives sheets conveyed one by one from the image forming unit, superimposes a plurality of sheets, and discharges them to the post-processing unit; and a sheet that is conveyed one by one from the image forming unit A bypass unit that discharges toward the post-processing unit without going through, and a control unit that selects one of the standby unit and the bypass unit as a conveyance direction of a sheet conveyed from the image forming unit, When invalid paper is discharged from the image forming unit, the control unit discharges the invalid paper after waiting the valid paper according to a predetermined condition when there is valid paper waiting in the standby unit. A paper superimposing unit that determines whether to discharge the valid paper in the standby unit after discharging the invalid paper through the bypass unit.   When the invalid paper is discharged from the image forming unit, the control unit is configured such that the interval between the valid paper waiting in the standby unit and the invalid paper is equal to or greater than the interval necessary for receiving the paper in the post-processing unit. For example, after the effective paper in the standby unit is discharged, the invalid paper is discharged toward the post-processing unit, and if the interval is smaller than the necessary interval, the invalid paper is passed through the bypass unit. 2. The paper superimposing unit according to claim 1, wherein the valid paper in the standby unit is discharged after being discharged first.   The control unit, when discharging the invalid paper first through the bypass unit and then discharging the valid paper waiting in the standby unit, conveys the valid paper and the invalid paper in the standby unit next to each other. The paper superimposing unit according to claim 1, wherein the sheet is discharged after being overlapped with the effective paper to be superposed in the standby unit.   3. The sheet stacking according to claim 1, wherein, when discharging the invalid paper after discharging the valid paper in the standby unit, the control unit discharges the invalid paper via the standby unit. 4. Matching part.   5. The sheet superposing unit according to claim 1, wherein the control unit discharges the invalid paper via the standby unit when there is no standby valid paper in the standby unit.   When the invalid paper is discharged via the standby unit, the control unit discharges the invalid paper after the invalid paper is overlapped by the standby unit when a plurality of invalid papers are continuous. The sheet superposition part according to claim 4 or 5.   7. The paper superimposing unit according to claim 6, wherein when the invalid paper is superimposed by the standby unit, the control unit performs discharge when the number of invalid papers reaches a predetermined number.   When discharging the invalid paper via the standby unit, the control unit causes the standby unit to wait for the valid paper after discharging the invalid paper when the valid paper is conveyed next to the invalid paper. The paper superposition part according to claim 4.

Images