JP2020093925A - Sheet processing apparatus and image forming system - Google Patents

Abstract

To disperse and carry sheets between a first sheet carrying path and a second sheet carrying path.SOLUTION: A sheet processing apparatus includes: a first sheet carrying path that carries a sheet to sheet supporting means; and a second sheet carrying path that branches from the first sheet carrying path at a branching part on the first sheet carrying path, and joins with the first sheet carrying path at a joining part upstream of a sheet outlet to the sheet supporting means in a sheet carrying direction. Control means controls guide means so that a first sheet which is first carried in a sheet bundle processed by sheet processing means is guided to the second sheet carrying path, and a second sheet following the first sheet is guided to the first sheet carrying path, and the first and second sheets join together at the joining part in an overlapping manner. The control means guides at least one sheet following the second sheet of a plurality of sheets forming the sheet bundle to the second sheet carrying path.SELECTED DRAWING: Figure 6

Description

The present invention relates to a sheet processing apparatus and an image forming system that process a sheet.

Conventionally, a sheet processing apparatus conveys a sheet discharged from an image forming apparatus such as a printer or a copying machine onto a processing tray, and then aligns the ends of the sheet bundle accumulated on the tray (hereinafter referred to as alignment) and binds the sheets. Work (hereinafter referred to as stapling) is being performed. While a sheet is being processed on the processing tray, subsequent sheets cannot be sent to the processing tray, so the sheets discharged from the image forming device are temporarily stored in the sheet processing device until the processing on the processing tray is completed. However, there are devices that do not reduce the productivity of the entire system.

For example, according to the sheet processing apparatus described in Patent Document 1, a normal transport path and a second transport path are provided as the transport paths following the processing tray. Then, while the preceding sheet is being processed on the processing tray, the subsequent first sheet is conveyed to the second conveying path, and the conveying roller is stopped by the electromagnetic clutch to be retained in the second conveying path. Further, the second sheet following the first sheet is conveyed to a normal path, the retained first sheet is restarted in conformity with the second sheet, and the first and second sheets are overlapped with each other. By sending the first sheet to the processing tray in the state, the arrival of the first sheet in the processing tray is delayed. As a result, the sheet can be sent from the image forming apparatus to the sheet processing apparatus even while the sheet is being processed in the sheet processing tray, so that the sheet post-processing job can be performed without reducing the productivity of the entire system. There is.

In addition, when the processing time of the preceding sheet in the processing tray is longer, a plurality of sheets subsequent to the first sheet are also retained in the second transport path, thereby similarly improving the productivity of the entire system. Post-processing jobs can be executed without dropping.

Japanese Patent Publication No. 6-99070

However, in the example of Patent Document 1 described above, while the preceding sheet is being processed in the processing tray, the subsequent first sheet is conveyed to the second conveying path, and the subsequent second sheet and thereafter are normal conveying paths. Be transported to. Even when the processing time of the preceding sheet in the processing tray is long, the plurality of subsequent sheets are conveyed to the second conveying path during the processing in the processing tray, but the processing in the processing tray is not performed. If not, all the remaining sheets are transported to the normal transport path. In other words, among the sheets conveyed to the processing tray, only the first few pages of the post-processing unit are conveyed to the second conveying path, so that as the cumulative number of sheets conveyed to the processing tray increases, normal It is conceivable that the difference in the sheet passing amount between the transport path and the second transport path becomes large. As a result, there is a problem that the influence on the sheet conveying performance due to the abrasion of the conveying rollers in the path and the accumulation of paper powder is biased toward the normal conveying path as compared with the second conveying path.

Therefore, it is an object of the present invention to provide a sheet processing apparatus and an image forming system that disperse and convey a sheet between a first sheet conveyance path and a second sheet conveyance path.

According to one aspect of the present invention, a sheet supporting unit configured to support a discharged sheet, a sheet processing unit configured to process a sheet bundle including a plurality of sheets discharged onto the sheet supporting unit, A first sheet conveying path that guides the sheet to the sheet supporting means, and a branch portion on the first sheet conveying path branches from the first sheet conveying path, and a sheet of the sheet is discharged from a discharge port to the sheet supporting means. A second sheet transport path that merges with the first sheet transport path at a merging portion upstream in the transport direction, and a sheet at the branch portion is selected as the first sheet transport path or the second sheet transport path. A guide unit that guides the guide unit and a control unit that controls the guide unit, and the control unit conveys the guide unit first in a sheet bundle to be processed by the sheet processing unit. The first sheet to the second sheet conveying path, the second sheet following the first sheet to the first sheet conveying path, and the first and second sheets At least one of the sheets following the second sheet among the plurality of sheets forming the sheet bundle is guided to the second sheet conveyance path in a manner that they are overlapped at the merging portion. It is a sheet processing apparatus characterized by controlling.

Further, according to one embodiment of the present invention, a sheet supporting unit configured to support a discharged sheet, a sheet processing unit configured to perform processing on a sheet bundle including a plurality of sheets discharged onto the sheet supporting unit, and a sheet A first sheet conveying path that guides the sheet to the sheet supporting means, and a branch portion on the first sheet conveying path that branches from the first sheet conveying path, and is more than a discharge port to the sheet supporting means. A second sheet conveying path that merges with the first sheet conveying path at a merging portion upstream in the sheet conveying direction, and a sheet at the branching portion that has the first sheet conveying path or the second sheet conveying path. A guide means for selectively guiding the guide means and a control means for controlling the guide means, the control means passing through the first sheet conveying path among a plurality of sheets forming the sheet bundle. The first mode in which the guiding means is controlled so that the number of sheets discharged to the sheet supporting means is increased, and the second sheet conveyance path among the plurality of sheets forming the sheet bundle is passed. And a second mode in which the guiding means is controlled so that the number of sheets discharged to the sheet supporting means is increased, and the second bundle mode can be executed by switching the sheet bundle unit. It is a sheet processing apparatus that does.

Further, according to one embodiment of the present invention, sheet supporting means for supporting discharged sheets, sheet processing means for processing a sheet bundle composed of a plurality of sheets discharged onto the sheet supporting means, A first sheet conveying path that guides the sheet to the sheet supporting means, and a sheet branching from the first sheet conveying path at a branch portion on the first sheet conveying path, and a sheet from a discharge port to the sheet supporting means. A second sheet conveying path that merges with the first sheet conveying path at a merging portion upstream of the conveying direction of the sheet and a sheet at the branching portion to the first sheet conveying path or the second sheet conveying path. A guide unit for selectively guiding and a control unit for controlling the guide unit are provided, and the control unit first conveys the guide unit in a sheet bundle processed by the sheet processing unit. The first sheet to be conveyed to the second sheet conveying path, and among the sheets following the first sheet of the sheet bundle, the sheet processing unit is configured to move the sheet bundle on the sheet supporting unit. A sheet processing apparatus, wherein in a non-processed state where no processing is performed, control is performed so as to guide at least one sheet whose leading end reaches the branch portion to the second sheet conveying path. is there.

According to the present invention, it is possible to disperse and convey sheets between the first sheet conveyance path and the second sheet conveyance path.

1 is a schematic configuration diagram of an image forming system according to a first embodiment. 3 is a block diagram of a hardware configuration of a sheet processing apparatus controller according to the first embodiment. FIG. FIG. 3 is a functional block diagram of the sheet processing apparatus according to the first embodiment. (A) is a diagram of sheet conveyance, and (b) is a schematic diagram for explaining the positional relationship of sheets. (A) is a schematic diagram for explaining the alignment process in the sheet processing apparatus, and (b) is a schematic diagram showing a case where the alignment process for the first sheet is not performed. (A) is a diagram of sheet conveyance in the sheet processing apparatus according to the first embodiment, and (b) is a diagram of sheet conveyance in the sheet processing apparatus according to the second embodiment. 3 is a control flowchart in the sheet processing apparatus according to the first embodiment of the present invention. It is a control flowchart in the sheet processing apparatus which concerns on the 2nd Embodiment of this invention. It is a block diagram of a hardware configuration of a sheet processing apparatus controller according to the third embodiment. It is a functional block diagram of the sheet processing apparatus concerning a 3rd embodiment. It is a control flowchart figure of the sheet conveyance concerning a 3rd embodiment. FIG. 6A is a schematic view showing the positional relationship of the sheets, and FIG. 6A is a state in which the leading edge of the third sheet is conveyed to the branch portion between the retracting conveyance path and the lower discharge conveyance path. (B) is a state in which the distance between the leading edge of the third sheet and the trailing edge of the first sheet is less than or equal to a predetermined distance. (C) is a state in which the fourth sheet has been conveyed. It is a control flowchart figure of the sheet conveyance in a 4th embodiment. It is a schematic diagram which shows the positional relationship of a sheet|seat, (a) is the state in which the 3rd sheet|seat was guided to the refuge conveyance path. (B) is a state in which the distance between the leading edge of the fourth sheet and the trailing edge of the second sheet is less than or equal to a predetermined distance. (C) A state in which the fifth sheet has been conveyed. It is a figure which shows the other example of the functional block diagram of a sheet processing apparatus.

Embodiments for carrying out the present invention will be illustratively described in detail below with reference to the drawings. However, the dimensions, materials, shapes, and their relative arrangements of the components described in this embodiment should be appropriately changed depending on the configuration of the apparatus to which the invention is applied and various conditions, and the scope of the invention. The present invention is not intended to be limited to the following embodiments. In the present embodiment, the sheet includes, in addition to plain paper, special paper such as coated paper, recording material having a special shape such as envelope and index paper, and plastic film or cloth for overhead projector. It includes. Further, the original document is also an example of the sheet, and the original document may be a blank sheet or may have an image formed on one side or both sides.

<First Embodiment>
(Schematic configuration of image forming system)
As shown in FIG. 1, an image forming system 1000 according to the present embodiment includes an image forming apparatus 1 that forms an image on a sheet, and a sheet processing apparatus 100 as a sheet processing apparatus mounted on the image forming apparatus 1. , Are provided. The image forming apparatus 1 is an image forming apparatus including an image forming unit 10 of a so-called intermediate transfer tandem system, which includes four image forming units 10Y, 10M, 10C, and 10K inside the apparatus body. The image forming apparatus 1 forms and outputs an image on the sheet S based on image information read from a document or image information input from an external device.

The image forming units 10Y, 10M, 10C, and 10K are electrophotographic units that form yellow (Y), magenta (M), cyan (C), and black (K) toner images. The configuration of each image forming unit is basically the same except that the color of the contained toner is different. Therefore, the image forming process will be described by taking the yellow image forming unit 10Y as an example.

When the image forming process is started, the photosensitive drum 5Y of the image forming unit 10Y configured by applying the organic photoconductive layer on the outer periphery of the aluminum cylinder is rotationally driven. The surface of the photosensitive drum 5Y is uniformly charged by the charging device 7Y and then exposed by the exposure device (for example, laser scanner) 9Y to form an electrostatic latent image. Then, the electrostatic latent image is visualized (developed) by the toner supplied from the developing device 11Y to form a toner image.

Similarly, in each of the image forming units 10M, 10C, and 10K, a toner image of a corresponding color is formed on the photosensitive drum. The toner images formed on the respective photosensitive drums are primarily transferred by the corresponding primary transfer rollers 6Y to 6K so as to overlap each other on the intermediate transfer belt 12 which is an intermediate transfer body.

In parallel with such an image forming process, the sheet feeding unit 4 executes a feeding operation of feeding the sheet S toward the image forming unit 10. The sheet feeding unit 4 includes a sheet supporting device such as a cassette 2 or a manual feed tray 3 that supports the sheet S, and a sheet feeding unit 4 that feeds the sheet S supported by the sheet supporting device. The sheet feeding unit 4 includes a mechanism such as a retard separation type and a separation pad type, and separates the sheets S one by one and feeds them to the registration unit 23.

The registration unit 23 corrects the skew of the sheet S and conveys the sheet S toward the secondary transfer unit 25 in accordance with the progress of the image forming process in the image forming unit 10. In the secondary transfer portion 25, the secondary transfer outer roller 9 and the secondary transfer inner roller 18c are arranged so as to sandwich the intermediate transfer belt 12. Then, in the secondary transfer nip between the secondary transfer outer roller 9 and the intermediate transfer belt 12, the toner image carried on the intermediate transfer belt 12 is secondarily transferred to the sheet S. Transfer residual toner remaining on the intermediate transfer belt 12 is removed by the belt cleaning device 21. The secondary transfer outer roller 9 contacts the intermediate transfer belt 12 as shown by the solid line during the secondary transfer, but is separated at the position shown by the dotted line when the secondary transfer is not performed.

The sheet S to which the unfixed toner image is transferred is transferred to the fixing device 13, and is sandwiched between the heating roller pairs 14 and 15 to be heated and pressed, whereby the toner is melted and fixed (fixed). Is done. The sheet S on which the image has been fixed is delivered to the sheet processing apparatus 100. In this embodiment, the sheet on which the image is fixed is directly discharged to the sheet processing apparatus 100 by the heating roller pair 14 and 15 of the fixing device 13. However, a discharge roller pair may be provided between the fixing device 13 and the discharge port of the image forming apparatus 1, and the discharge roller pair may convey the sheet to the sheet receiving port of the sheet processing apparatus 100.

The sheet processing apparatus 100 receives the image-formed sheets sent from the image forming apparatus through the receiving path 112, sorts and stacks the sheets on the upper discharge tray 103 and the lower discharge tray 104. When the sheets are sorted into the upper discharge tray 103 and the lower discharge tray 104, the switching flapper 101 is driven by a solenoid (not shown) to switch the transport path. That is, when the sheet is discharged to the upper discharge tray 103, the sheet is conveyed to the upper discharge conveyance path 109, and when the sheet is discharged to the lower discharge tray 104, the sheet is conveyed to the lower discharge conveyance path 110. Further, the evacuation transport path 111 is a path branched at the branch portion 114 on the lower discharge transport path 110, and is returned to the lower discharge transport path 110 again at the lower discharge merging point 113 immediately before the discharge port to the lower discharge tray 104. Join together. It should be noted that, in the present embodiment, the merging point constitutes a merging portion that is located upstream of the discharge port to the sheet supporting unit 104 in the sheet conveying direction. The lower discharge transport path 110 includes a lower discharge transport upstream roller 120 and a lower discharge transport downstream roller 121, and the retract transport path 111 includes a retract transport upstream roller 122 and a standby transport downstream roller 123. Driven by. The transfer path is switched to the retracted transfer path 111 by the discharge transfer switching flapper 102. The usage of the evacuation transport path 111 will be described later.

The lower discharge tray 104 is provided with a staple unit 105, a staple unit moving mechanism 115, and an alignment belt 106, and the following post-processing can be performed. The aligning belt 106 descends so as to come into contact with the sheet by a lifting motor (not shown) when the rear end of the sheet conveyed to the lower discharge tray 104 passes through the discharge roller 107, and then a driving motor (not shown). Rotates counterclockwise (in the figure, in the direction of the arrow). Then, the sheet is brought into contact with the stopper 108 to perform alignment processing in the carry-out direction. When performing stapling, after a predetermined number of sheets are stacked on the lower discharge tray 104 to form a bundle, the stapling unit moving mechanism 115 moves the stapling unit 105 to the stapling position, and the stapling unit 105 performs stapling processing. Done. While the stapling process is being performed, the lower discharge tray 104 cannot receive a subsequent sheet.

(Hardware configuration of image forming system)
Next, the hardware configuration of the image forming system 1000 around the sheet processing apparatus 100 will be described with reference to FIG. Note that, here, the configuration related to the conveyance to the upper discharge tray 103 is omitted. Reference numeral 301 is a controller that controls the image forming apparatus 1 and the sheet processing apparatus 100, 302 is an engine control unit that controls the image forming apparatus 1, and 303 is a sheet processing apparatus controller that controls the sheet processing apparatus 100. Reference numeral 304 denotes a serial command transmission signal line for transmitting a command from the controller 301 to the engine control unit 302 and 305 for transmitting an instruction from the controller 301 to the sheet processing apparatus controller 303 by serial communication. Reference numeral 306 denotes a serial status transmission signal line for transmitting status data by serial communication from the engine control unit 302 to the controller 301 in response to a command, and 307 from the sheet processing apparatus controller 303 to the controller 301. When performing the printing operation, the controller 301 transmits a serial command to the engine control unit 302 and the sheet processing apparatus controller 303. The control is performed by receiving status data from the engine control unit 302 and the sheet processing apparatus controller 303. In this way, when a plurality of devices are connected and operate, the controller 301 centrally manages the control and state of each device, and maintains the consistency of the operation between each device.

The sheet processing apparatus controller 303 is a control IC, and includes a CPU 231 that controls various operations of the sheet processing apparatus and a RAM 232 that temporarily stores control data necessary for the operation of the sheet processing apparatus. Further, it is provided with a ROM 233 that stores a program and a control table necessary for the operation of the sheet processing apparatus in a nonvolatile manner, and a communication module 234 that performs a communication process with the controller 301 and the like. Further, the sheet processing apparatus 100 is provided with an I/O port 240 for inputting/outputting control signals to/from various units. The staple unit drive circuit 201 and the staple unit movement motor drive circuit 202 receive control signals from the sheet processing apparatus controller 303 and drive the staple unit 105 and the staple unit movement mechanism 115 in the post-processing unit 211. Further, the alignment belt motor drive circuit 203, the lower discharge motor drive circuit 204, and the discharge/transport switching solenoid drive circuit 205 similarly receive the control signals to drive the alignment belt 106, the lower discharge/transport motor 330, and the discharge/transport switching solenoid 331. To do.

FIG. 3 is a control block diagram for explaining the conveyance control performed by the sheet processing apparatus controller 303. Note that, here, the configuration related to the conveyance to the upper discharge tray 103 is omitted. In FIG. 3, the sheet processing apparatus controller 303 includes a conveyance control unit 308, a post-processing unit control unit 309, a lower discharge motor control unit 313, and a discharge conveyance switching solenoid control unit 314. The transport control unit 308 performs a discharge transport operation in accordance with a discharge control command from the controller, and also instructs the post-processing unit control unit 309 to perform post-processing on the sheets and the sheet bundle discharged from the image forming apparatus. The post-processing unit controller 309 controls the stapling unit 105, the stapling unit moving mechanism 115, and the aligning belt 106 in the post-processing unit 211. When the sheet discharge destination is the lower discharge tray 104, the transport control unit 308 drives the lower discharge transport motor 330 by the lower discharge motor control unit 313 to cause the lower discharge transport upstream roller 120 in the lower discharge transport path 110. And, the lower discharge conveyance downstream roller 121 is rotated. Further, the retracted conveyance upstream roller 122 and the retracted conveyance downstream roller 123 in the retracted conveyance path 111 are rotated. When the discharge destination of the sheet is the lower discharge tray 104, the discharge path switching control unit 320 of the transport control unit 308 determines whether the sheet is sent to the retracted transport path 111 or the lower discharge transport path 110. Then, the discharge/transport switching solenoid control unit 314 drives the discharge/transport switching solenoid 331, and the discharge/transport switching flapper 102 switches the transport path.

(Structure of the escape transport path)
Next, the relationship between the retracted transport path 111 and the productivity of the entire apparatus when performing post-processing on the lower discharge tray 104 will be described. FIG. 4A is a diagram showing the relationship between the position of the leading edge of the sheet and time, with the vertical axis representing the position in the lower discharge transport path 110 and the horizontal axis representing the elapsed time. The starting point of the vertical axis is the starting position of the lower discharge transport path 110, that is, the position branched from the receiving path 112 by the discharge destination switching flapper 101. When the post-processing for the preceding sheet bundle is not performed, the sheet enters the lower discharge transport path 110 (A in FIG. 4A) and then the discharge transport switching flapper 102 position (B in FIG. 4A). , The position of the lower discharge confluence 113 (C in FIG. 4A) and the discharge roller 107. Then, the discharge to the lower discharge tray 104 is completed (H in FIG. 4A). From the time when the discharge of the final sheet of the first bundle to the lower discharge tray 104 is completed, that is, the time when the trailing edge of the third sheet passes the position of the discharge roller 107 (D in FIG. 4A), A stapling process for a bundle of three sheets is performed on the discharge tray 104. In order to maximize the print productivity of the system, it is necessary for the sheet processing apparatus 100 to accept the sheets sent at the maximum productivity intervals of the image forming apparatus. On the other hand, the stapling process on the sheet bundle requires a certain amount of time, and the subsequent sheets cannot be received in the lower discharge tray 104 during the stapling process. Here, the transport path of the first sheet S11 of the subsequent bundle is switched by the discharge transport switching flapper 102, and is transported to the retract transport path 111 (E in FIG. 4A). The evacuation transport path 111 has a longer path length to the lower discharge confluence point 113 than the lower discharge transport path 110. That is, the path length of the second sheet carrying path (111) between the branching section 114 and the merging section 113 is longer than the path length of the first sheet carrying path (110). Therefore, it is possible to delay the timing when the first sheet S11 of the subsequent bundle arrives at the lower discharge joining point 113 (F in FIG. 4A). In this figure, a section E-F in which the sheet S11 travels along the escape transport path 111 is indicated by a dotted line, and reaches the lower discharge confluence point 113 substantially overlapping the subsequent sheet S12 transported to the lower discharge transport path 110. .. FIG. 4B shows the positional relationship of the sheets in the transport path at the timing when the leading edge of the second sheet S12 and the leading edge of the first sheet S11 reach the lower discharge merge point 113 and merge.

As described above, when performing the post-processing on the lower discharge tray 104, the first sheet of the subsequent bundle is diverted to the retracted conveyance path 111, so that the sheet processing apparatus 100 can always operate from the image forming apparatus 1. Sheets can be received at regular intervals. The sheet S11 that has detoured to the retracted transport path 111 and the subsequent sheet S12 that has been transported to the lower discharge transport path 110 need to be merged at the lower discharge merge point 113 so as to overlap with each other for alignment processing described later. .. For that purpose, the path length of the evacuation conveyance path 111 is set to be longer than the path length of the lower ejection conveyance path 110, or the conveyance speed of the sheet S11 in the evacuation conveyance path is set to the sheet in the lower ejection conveyance path 110. It is necessary to have a configuration that is slower than the transport speed in S12. In the present embodiment, the lower discharge transport upstream roller 120 and the lower discharge transport downstream roller 121, and the retract transport upstream roller 122 and the standby transport downstream roller 123 are fixed by the same lower discharge transport motor 330 (see FIG. 2). Driven at speed. The speed is the same as the transport speed of the upstream receiving path 112. Therefore, the path length of the evacuation conveyance path 111 is such that the leading edge of the first sheet S11 at the timing when the leading edge of the second sheet S12 of the second bundle conveyed through the lower ejection transportation path 110 reaches the lower ejection confluence point 113. Are designed to have such a length that they reach the lower discharge merging point 113 and merge. Therefore, the merged first sheet S11 and second sheet S12 are discharged to the lower discharge tray 104 in a state of substantially overlapping each other.

The time T_DG from the trailing edge of the last sheet of the bundle passing through the discharge roller 107 to the leading edge of the first sheet (first sheet S1) of the next bundle reaching the discharge roller 107 is the productivity of the image forming apparatus. It is the time determined by. In order to maximize the productivity of the system in the maximum throughput of the image forming apparatus without causing the loss time by the sheet processing apparatus 100, the time T_process required for the bundle aligning process and the stapling process is the maximum throughput of the image forming device. It must be designed to be shorter than the value of T_DG at time. If T_process is longer than this, it is necessary to reduce the productivity of the image forming apparatus and increase the distance between sheets.

As can be seen from FIG. 4A, among the sheets discharged to the lower discharge tray 104, only the first sheet of the bundle to be post-processed passes through the retracted conveyance path 111. That is, the greater the number of sheets per bundle when performing the post-processing, and the greater the number of bundles (the number of bundles) to be subjected to the post-processing, the more the number of sheets passed through the lower discharge conveyance path 110. Will end up. Normally, in such a sheet processing apparatus, a large number of sheets are passed through during the period of use of the apparatus.Therefore, the characteristics of the sheet transportation performance may change due to the abrasion of the transportation rollers or the influence of the accumulation of paper dust in the path. is there. As in this example, in a configuration in which sheets that have passed through different conveyance paths are merged and overlapped, if the paper passing amount is biased to one path, the degree of influence of the roller wear and paper dust accumulation on the conveyance performance is It may be bigger than the pass. In that case, the following problems may occur in the matching process.

(Example of problems in matching processing due to uneven paper feed amount)
Here, with reference to FIG. 5, a description will be given of the alignment process for the two sheets that have merged at the lower discharge merge point 113 and have been conveyed to the lower discharge tray 104. With respect to these two sheets discharged in an overlapping manner, the trailing edge of the first sheet S11 of the bundle is pulled back to the aligning belt 106 before the trailing edge of the second sheet S12 of the bundle, and reaches the stopper 108. bump into. Then, after that, the second sheet S12 of the bundle slides on the first sheet S11 of the bundle and is similarly aligned by the stopper 108. For that purpose, as shown in FIG. 5A, the second sheet S12 in the upper stack is discharged to the lower discharge tray 104 in a state of being advanced from the first sheet S11 in the lower stack. There is. Here, when the transport performance greatly changes only in one of the passes, the deviation amount L_shift between the leading edge of the sheet S12 transported in the lower discharge transport path 110 and the leading edge of the sheet S11 transported in the retract transport path 111 is as designed. As a result, the desired matching process may not be performed. In particular, the transport of S12 is delayed due to only the transport performance of the lower discharge transport path 110 being reduced, and the second sheet S12 that is on the upper side as shown in FIG. If the sheet S11 is discharged to the lower discharge tray 104 after the sheet S11 is delayed, the alignment process for the lower side S11 is not performed.

(Path switching control)
As described above, the path switching control is executed in the present embodiment so that the sheet passing amount is not extremely biased between the lower discharge transport path 110 and the retract transport path 111. That is, in the present embodiment, the occurrence of loss time by the sheet processing apparatus 100 is avoided, the amount of paper passing in both passes is dispersed, and the influence of the roller wear and the paper dust accumulation on the conveying performance is affected only in one pass. The path can be switched so that it does not grow.

FIG. 6A is a diagram showing the relationship between the sheet leading end position and the time when the sheet is conveyed through the lower discharge conveyance path by the path switching control according to the present embodiment, and staples every five sheets. 9 illustrates an example in which processing is performed on a plurality of copies. The description of the position of the leading edge of the sheet on the vertical axis and the description of the retracted conveyance path indicated by the dotted line are the same as in FIG. That is, a section from the position of the discharge/conveyance switching flapper 102 to the position of the lower discharge/confluence point 113 where the sheet S11 advances along the retracted conveyance path 111 is shown by a dotted line, and when it advances along the lower discharge conveyance path 110, it is shown by a solid line. There is.

As shown in FIG. 6A, the last sheet of each bundle is discharged to the lower discharge tray 104 through the lower discharge transport path 110, and while the sheet bundle is being post-processed on the lower discharge tray 104, The first sheet of the subsequent bundle is passed through the retracted transport path 111. On top of that, a bundle in which the number of sheets passing through the lower discharge transport path 110 is large (first bundle, third bundle, and fifth bundle) and a bundle in which the number of sheets passing through the retracting transport path 111 is large (second bundle) The transport path is switched so that (4th bundle) is alternately repeated. The sheets sent from the image forming apparatus to the lower discharge transport path 110 at a constant interval are subjected to post-processing while maintaining productivity, and the number of sheets passing through the lower discharge transport path 110 and the standby transport path 111 is almost the same. It turns out to be the same.

FIG. 7 is a flow chart of the path switching control performed by the discharge path switching control unit 320 when the sheet S1 is discharged to the lower discharge tray 104 for realizing the present invention. In the present flowchart, the sheet S1 will be described on the assumption that it is the second and subsequent sheets of the job, but in the implementation of the present invention, the first sheet of the job is selected for simplification of the control program. There is no problem if applied to it.

In step S101, it is determined whether the sheet S1 is the first sheet of the sheet post-processing bundle performed on the lower discharge tray 104. If it is the first sheet in the bundle, the next sheet cannot be received on the lower discharge tray 104 because post-processing has been performed on the preceding bundle. Therefore, the sheet S1 is sent to the retracted conveyance path 111 in step S104.

Here, the discharge path switching control unit 320 stores a path selection mode, which is an internal control state, in the RAM 232, and has two states, that is, a standby transfer path sheet passing mode and a lower discharge transfer path sheet passing mode. The post-processing bundles are alternately switched. That is, in step S106, when the current path selection mode is the retracted conveyance path sheet passage mode, the path selection mode is switched to the lower discharge conveyance path sheet passage mode (step S107). On the other hand, if the current pass selection mode is not the standby conveyance path sheet passing mode, the path selection mode is switched to the standby conveyance path sheet passing mode (step S108). The pass selection mode stored here is applied to the pass switching control for the second and subsequent sheets of the bundle.

If No in step S101, that is, if the sheet S1 is not the first sheet of the sheet post-processing bundle to be performed on the lower discharge tray 104, the sheet S1 is set to the sheet post-processing bundle to be performed on the lower discharge tray 104 in step S102. Determine if it is the last page. If it is the final sheet of the bundle for post-processing (Yes in S102), the sheet is sent to the lower discharge transport path 110 in S105. That is, the final sheet of the plurality of sheets forming the sheet bundle is guided to the lower discharge transport path 110 as the first sheet transport path. If the sheet S1 is neither the first sheet of the post-processing bundle nor the final page of the post-processing bundle (No in S102), the conveyance destination of the sheet S1 is switched according to the current path selection mode in step S103. That is, if the current path selection mode is the lower discharge transport path sheet passing mode (No in S103), the sheet is sent to the lower discharge transport path 110 in step S105. On the other hand, if the current path selection mode is the retracted conveyance path sheet passing mode (Yes in S103), the sheet is sent to the retracted conveyance path 111 in S104.

As described above, according to the present embodiment, it is possible to maintain system productivity in a configuration in which sheets that have passed through different conveyance paths are merged and overlapped. Further, the conveyance paths are switched so that the paper passing amounts of both paths are dispersed, and it is possible to prevent the degree of influence on the conveyance performance due to the abrasion of the rollers and the accumulation of paper dust from being concentrated on one path. Accordingly, even if the cumulative sheet passing amount of the sheets to the post-processing tray becomes large, the positional relationship of the overlapped sheets is maintained as designed, and post-processing such as alignment is correctly performed.

Further, in the present embodiment, the lower discharge tray 104 can be said to be a sheet supporting unit that supports discharged sheets, and the post-processing unit 211 is a sheet bundle including a plurality of sheets discharged onto the sheet supporting unit. It can be said to be a sheet processing means for performing processing on Further, the lower discharge transport path 110 can be said to be a first sheet transport path that transports a sheet to the sheet supporting unit. Further, the retracting conveyance path 111 branches off from the first sheet conveyance path at a branch portion on the first sheet conveyance path, and at the confluence portion upstream of the sheet conveyance direction in the sheet conveyance direction from the first sheet conveyance means. It can be said that it is the second sheet conveyance path that merges with the sheet conveyance path. Further, the discharge/conveyance switching flapper 102 can be said to be a guiding means for selectively guiding the sheet to the first sheet conveying path or the second sheet conveying path at the branching portion, and the sheet processing apparatus controller 303 controls the guiding means. It can be said that it is a control means. In addition, in the lower discharge/conveyance path sheet passing mode in the present embodiment, the first guiding means is controlled so that the number of sheets discharged to the sheet supporting means via the first sheet conveying path is increased. It can be called a mode. Further, in the retracting conveyance path sheet passing mode, the guiding means is arranged so that the number of sheets discharged to the sheet supporting means via the second sheet conveying path among the plurality of sheets forming the sheet bundle is increased. It can be said to be the second mode for controlling. When the sheet processing means continuously processes a plurality of sheet bundles, the control means can switch between the first mode and the second mode in units of the sheet bundles and execute them. More specifically, the first mode and the second mode are alternately switched for each sheet bundle. Therefore, of the total number of sheet bundles processed in the input sheet processing job, the number of sheet bundles processed in the first mode and the number of sheet bundles processed in the second mode. Are substantially equal to each other (for example, the difference between the number of sheet bundles processed in the first mode and the number of sheet bundles processed in the second mode is 1 or less). It is running.

As described above, in the second mode, of the sheet bundle of which the leading end reaches the branch portion after the processing by the sheet processing unit on the preceding sheet bundle discharged immediately before the sheet bundle of the sheet bundle is completed. At least one sheet is conveyed to the evacuation conveyance path 111. That is, in the second mode, the control means causes the guide means to cause the second bundle to move at least a part of the sheets by the guiding means when the sheet processing means is not processing the sheet bundle on the sheet supporting means. The sheet is guided to the sheet conveyance path. Therefore, among the sheets following the first sheet of the sheet bundle, at least one of the sheets whose leading end reaches the branch portion in the non-processing state is guided to the second sheet transport path. As a result, the sheets can be distributed and conveyed between the first sheet conveyance path and the second sheet conveyance path, and the total number of sheets conveyed during the input sheet processing job can be conveyed. , It is possible to balance the size relationship between the number of sheets sent to the first sheet transport path and the number of sheets sent to the second sheet transport path.

It should be noted that in the above-described embodiment, the lower discharge serving as the sheet supporting means also serves as an intermediate processing tray for temporarily supporting the sheet for processing the sheet and a discharge tray for discharging the final product. The tray 104 is illustrated. However, the intermediate processing tray and the discharge tray may be provided separately, and the intermediate processing tray may be used as the sheet supporting means. Further, although the post-processing unit 211 including the staple unit 105 is illustrated as the sheet processing unit, for example, the sheet processing unit may be configured to include a punch unit that punches holes in the sheet.

In addition, in the present embodiment, an example has been described in which the discharge path switching control unit 320 alternately switches the path selection mode for each bundle. In the job received by the sheet processing apparatus controller 303, when the total number (copies) of the bundle to be subjected to the post-processing is known in advance, the discharge path switching control unit 320 sets the number of copies in each mode to half of the total number of copies. As described above, the scheduling may be performed such that the path selection mode is switched for each number of copies. That is, as in the case where the path selection mode is alternately switched for each conveyed sheet bundle, the number of sheet bundles processed in the first mode and the number of sheet bundles processed in the second mode. Scheduling may be performed such that the path selection mode is switched for each of a plurality of copies so that the difference between and is 1 or less. For example, when it is known that the total number of copies is a staple job, the first half 5 copies are conveyed in the lower discharge conveyance path sheet passing mode, and the second half 5 copies are conveyed in the retract conveyance path sheet passing mode. Such an embodiment is also possible.

<Second Embodiment>
Next, a second embodiment according to the present invention will be described. In the above-described first embodiment, the method of managing the distribution of the sheet passing amount between the lower discharge transport path 110 and the retract transport path 111 by using the bundle of post-processing as one unit has been described. On the other hand, the present embodiment is different in that the path switching control is executed so as to distribute the distribution of the sheet passing amount to both paths in one bundle of post-processing. In the following description, only the points different from the first embodiment will be described, and other points will be denoted by the same reference numerals as those in the first embodiment, and the description thereof will be omitted.

FIG. 6B is a diagram showing the relationship between the sheet leading end position and time when the sheet is conveyed through the lower discharge conveyance path by the path switching control according to the present embodiment. Similar to the embodiment, the stapling process for every five sheets is performed on a plurality of copies. As shown in FIG. 6B, the last sheet of each bundle is discharged to the lower discharge tray 104 through the lower discharge transport path 110, and while the sheet bundle is being post-processed on the lower discharge tray 104, The first sheet of the subsequent bundle is passed through the retracted transport path 111. Then, in the bundle to be subjected to the post-processing, the transport paths are switched so that the sheets passing through the lower discharge transport path 110 and the sheets passing through the retract transport path 111 alternate. Sheets that are sent from the image forming apparatus to the lower discharge conveyance path 110 at regular intervals are subjected to post-processing without causing a loss time in the sheet processing apparatus, and pass through the lower discharge conveyance path 110 and the standby conveyance path 111. It can be seen that the number of sheets is almost the same.

FIG. 8 is a flowchart of the path switching control in this embodiment performed by the discharge path switching control unit 320 when the sheet is discharged to the lower discharge tray 104. Note that, like the first embodiment, in the present flowchart, description will be made on the assumption that the sheets are the second and subsequent sheets of the job, but in implementing the present invention, in order to simplify the control program. There is no problem if it is applied to the first sheet of the job.

In step S201, it is determined whether or not the sheet is the first sheet in the sheet post-processing bundle on the lower discharge tray 104. If it is the first sheet in the bundle, the next sheet cannot be received on the lower discharge tray 104 because post-processing has been performed on the preceding bundle. Therefore, the sheet S1 is sent to the retracted conveyance path 111 in step S204. If No in step S201, that is, if the sheet S1 is not the first sheet of the sheet post-processing bundle performed on the lower discharge tray 104, it is determined in step S202 whether the sheet is the final sheet of the post-processing bundle. When the sheet is the final sheet of the post-processing bundle (Yes in S202), the sheet is sent to the lower discharge transport path 110 in S205. When the sheet is not the final sheet of the post-processing bundle (No in S202), it is determined in step S203 whether the sheet S1 is an even-numbered sheet of the post-processing bundle. If the sheet S1 is the even-numbered sheet of the bundle (Yes in S203), the sheet is sent to the lower discharge transport path 110 in S205. On the other hand, when the sheet S1 is an odd-numbered sheet in the bundle (No in S203), the sheet S1 is sent to the retracted conveyance path 111 in S204.

As described above, in the present embodiment, the control unit (303) moves the first sheet (S1) first conveyed in the sheet bundle processed by the sheet processing unit to the second sheet conveyance path. And guides the second sheet (S2) following the first sheet to the first sheet conveying path so that the first and second sheets join together in a manner where they overlap each other at the joining portion. Can be said to control. Then, the control unit guides at least one of the plurality of sheets forming the sheet bundle, which is subsequent to the second sheet, to the second sheet transport path. More specifically, a sheet following the second sheet of the plurality of sheets forming the sheet bundle is alternately guided to the first sheet transport path and the second sheet transport path for each unit number of sheets. The guide means is controlled so that Then, by guiding at least one sheet subsequent to the second sheet to the second sheet transport path, the sheet is discharged to the second sheet during the sheet dischargeable period in which the post-processing for the preceding sheet bundle is completed. Transporting to the transport path. That is, the sheet processing means processes the sheet bundle on the sheet supporting means when the leading end of the sheet guided by the second sheet conveying path among the sheets following the second sheet reaches the branch portion. It is in a non-processed state that has not been subjected to. As a result, the sheets can be distributed and conveyed between the first sheet conveyance path and the second sheet conveyance path, and the total number of sheets conveyed during the input sheet processing job can be conveyed. , The balance between the number of sheets sent to the first sheet transport path and the number of sheets sent to the second sheet transport path is balanced. In addition, in the present embodiment, the unit number is set to 1, but the number is not limited to this, and a number such as 2 or 3 may be set.

<Third Embodiment>
Next, a third embodiment according to the present invention will be described. In the above-described first embodiment, the rollers 120 and 121 in the lower discharge transport path 110 and the rollers 122 and 123 in the retract transport path 111 are driven by the lower discharge transport motor 330 in conjunction with each other. For this reason, the transport speed of the sheet transported in the lower discharge transport path 110 and the retract transport path 111 cannot be individually set. The present embodiment is different from the above-described first embodiment in that it is configured such that the conveyance speeds of the sheets conveyed in the conveyance paths 110 and 111 can be set independently. ing. In the following description, only the points different from the first embodiment will be described, and other points will be denoted by the same reference numerals as those in the first embodiment, and the description thereof will be omitted.

FIG. 9 is a diagram showing a hardware configuration of the image forming system 1000 around the sheet processing apparatus 100 according to the present embodiment. FIG. 10 is a control block diagram for explaining the conveyance control performed by the sheet processing apparatus controller 303 according to this embodiment. As shown in FIGS. 9 and 10, in the present embodiment, the lower discharge transport downstream clutch 332 is disposed on the power transmission path between the lower discharge transport motor 330 and the lower discharge transport downstream roller 121. There is. Further, a retracting conveyance downstream clutch 333 is arranged on the power transmission path between the lower discharge conveying motor 330 and the retracting conveyance downstream roller 123.

The lower discharge transport downstream clutch 332 is configured to be driven by the lower discharge transport downstream clutch drive circuit 206, and rotates and stops the lower discharge transport downstream roller 121. The shelter conveyance downstream clutch 333 is configured to be driven by the shelter conveyance downstream clutch drive circuit 207, and rotates and stops the shelter conveyance downstream roller 123. In addition, the sheet stop control unit 321 of the transport control unit 308 determines whether to stop the sheets in the lower discharge transport path 110 and the retreat transport path 111, or to release the stopped sheet. The sheet stop control unit 321 uses the clutch control unit 315 to rotate and stop the lower discharge transport downstream roller 121 by the lower discharge transport downstream clutch 332 based on the determination result described later. Further, the shelter conveyance downstream roller 123 is rotated and stopped by the shelter conveyance downstream clutch 333.

(Discharge transfer control)
Next, sheet discharge/conveyance control using the lower discharge/conveyance downstream clutch 332 and the retraction/conveyance downstream clutch 333 will be described with reference to FIGS. In the following description, the transport control of the second bundle of sheets will be described on the assumption that the preceding bundle of sheets has been discharged onto the lower discharge tray 104. Further, in the following description, an example in which the staple processing is performed with a bundle of three sheets is shown.

FIG. 11 is a flowchart for controlling switching between the lower discharge transport path 110 and the retract transport path 111 by the transport control unit 308 in transporting the second bundle of sheets, and controlling the transport stop and the transport restart of the sheet in the two transport paths described above. Is. First, the conveyance control of the first sheet S1 of the bundle will be described. In step S301, the conveyance control unit 308 determines whether the sheet is the first sheet in the bundle of sheet post-processing performed on the lower discharge tray 104. When it is determined that the sheet is the first sheet of the bundle, the discharge path switching control unit 320 switches the discharge/conveyance switching flapper 102 to send the sheet S1 to the retracted conveyance path 111 in step S302. When it is determined in step S303 that the sheet S1 reaches the retracted conveyance downstream roller 123 by the conveyance control unit 308, the sheet conveyance stop downstream clutch 333 is operated by the sheet stop control unit 321 in step S304. Then, the retracting conveyance downstream roller 123 is stopped, and the sheet S1 is stopped in the retracting conveyance path 111.

Next, the conveyance control of the second sheet S2 of the bundle will be described. In step S301, the conveyance control unit 308 determines that it is not the first sheet of the bundle, and then in step S305, the conveyance control unit 308 determines whether the sheet is the second sheet of the bundle. When it is determined that the sheet is the second sheet in the bundle, the discharge path switching control unit 320 switches the discharge/transport switching flapper 102 to send the sheet S2 to the lower discharge/transport path 110 in step S306. When it is determined in step S307 that the sheet S2 has reached the lower discharge transport downstream roller 121 by the transport control unit 308, the lower discharge transport downstream clutch 332 is operated by the sheet stop control unit 321 in step S308. Then, the lower discharge conveyance downstream roller 121 is stopped, and the sheet S2 is stopped in the lower discharge conveyance path 110.

Next, the conveyance control of the third sheet S3 of the bundle will be described. In steps S301 and S305, the conveyance control unit 308 determines that the sheets are not the first and second sheets of the bundle, and then in step S309, the conveyance control unit 308 determines whether the sheets are the third sheet of the bundle. .. When it is determined that the sheet is the third sheet in the bundle, the discharge path switching control unit 320 switches the discharge/transport switching flapper 102 to send the sheet S3 to the retracted transport path 111 in step S310. FIG. 12A shows a sheet S1 when stopped in the retracted transport path 111, a sheet S2 when stopped in the lower discharge transport path 110, and a sheet S3 transported to the retracted transport path 111. Show. If it is determined in step S311 that the distance between the leading end of the sheet S3 and the trailing end of the sheet S1 is within the predetermined distance L in step S311, the sheet stop controller 321 releases the retracted conveying downstream clutch 333 in step S312. .. Then, the retracted conveyance downstream roller 123 is rotated, and the conveyance of the sheet S1 is restarted so that the sheet S3 and the sheet S1 do not come into contact with each other. In the present embodiment, in consideration of the response time of the retracted conveyance downstream clutch 333, when the distance between the front end of the sheet S3 and the rear end of the sheet S1 is within 20 mm, it is determined that the distance is within the predetermined distance L. Then, the lower discharge transport downstream clutch 332 is released in accordance with the release of the retract transport downstream clutch 333 of the sheet S1 so that the sheet S1 and the sheet S2 overlap each other at the lower discharge merge point 113. Then, the lower discharge conveyance downstream roller 121 is rotated, and the conveyance of the sheet S2 is restarted. FIG. 12B is a diagram in which the sheet S3 is conveyed to the retracting conveyance path 111, the conveyance of the sheet S1 is restarted and the conveyance of the sheet S2 is restarted so that the sheets S3 and S1 do not come into contact with each other.

Next, the conveyance of the fourth sheet S4 of the bundle will be described. If the transport control unit 308 determines that the sheet is the fourth sheet in the bundle in step S309, the discharge path switching control unit 320 switches the discharge transport switching flapper 102 and sends the sheet to the lower discharge transport path 110 in step S313. FIG. 12C shows the position when the fourth sheet S4 of the bundle is being conveyed to the lower discharge conveying path 110. The fifth and subsequent sheets are also sent to the lower discharge transport path 110, similarly to the sheet S4.

By transporting in this way, the time from when the sheet S1 stops in the retracted transport path 111 to when the leading edge of the sheet S3 reaches the trailing edge of the sheet S1 can be assigned to the post-processing time of the preceding bundle. it can. When the third bundle of post-processing sheets is to be received subsequently to the second bundle, each sheet is sent to the post-processing unit 211 according to the flowchart of FIG.

As described above, according to the present invention, in a configuration in which post-processing is performed on a plurality of sheets obtained by merging sheets that have passed through different conveyance paths and performing post-processing on a plurality of sheets that have been overlapped, the time required for post-processing can be increased without reducing productivity It becomes possible.

It should be noted that in the present embodiment, the lower discharge conveyance downstream roller 121 can be said to be a first sheet conveying unit that conveys a sheet during the first sheet conveyance path. Further, it can be said that the retracting conveyance downstream roller 123 is a second sheet conveying unit that conveys a sheet in the second sheet conveying path and can be driven independently of the first sheet conveying unit. The control means (303) temporarily stops the first sheet (S1) in the second sheet conveyance path and temporarily stops the second sheet in the first sheet conveyance path. Then, the first and second sheet conveying means are arranged so as to release the stop of the first and second sheets before the front end of the third sheet (S3) following the second sheet reaches the rear end of the first sheet. It can be said that it controls.

<Fourth Embodiment>
Next, a fourth embodiment according to the present invention will be described. In the following description, only the points different from the third embodiment will be described, and the other points will be denoted by the same reference numerals as in the first to third embodiments, and the description thereof will be omitted. To do. The hardware configuration and control block for implementing the present embodiment are the same as those in the third embodiment. Further, a case will be described in which the length of the sheet to be conveyed is different from that in the third embodiment, and two sheets enter the retracted conveyance path 111. Further, the following description will be made by taking the conveyance control of the second bundle of sheets as an example, as in the third embodiment.

FIG. 13 is a flowchart of switching control between the lower discharge transport path 110 and the retract transport path 111 by the transport control unit 308 in transporting the second bundle of sheets, and sheet stop control in the transport path. The sheet conveyance control for the first and second sheets of the second bundle (S401 to S408) is the same as that of S301 to S308 of FIG. 11 described in the third embodiment, and a repetitive description will be omitted.

The transport control of the third sheet S3 of the second bundle will be described. In steps S401 and S405, the conveyance control unit 308 determines that the sheets are not the first and second sheets of the bundle, and then in step S409, the conveyance control unit 308 determines whether the sheets are the third sheet of the bundle. .. When it is determined that the sheet is the third sheet in the bundle, the discharge path switching control unit 320 switches the discharge/transport switching flapper 102 to send the sheet S3 to the retracted transport path 111 in step S410. FIG. 14A is a diagram in which the sheet S<b>1 is stopped at the retracted conveyance path 111, the sheet S<b>2 is stopped at the lower discharge conveyance path 110, and the sheet S<b>3 is conveyed to the retracted conveyance path 111.

Next, the conveyance control of the fourth sheet S4 of the second bundle will be described. In step S409, the conveyance control unit 308 determines that the sheet is not the third sheet in the bundle, and in step S411, the conveyance control unit 308 determines whether the sheet is the fourth sheet in the bundle. When it is determined that the sheet is the fourth sheet in the bundle, the discharge path switching control unit 320 switches the discharge/transport switching flapper 102 to send the sheet S4 to the lower discharge/transport path 110 in step S412.

If it is determined in step S413 that the distance between the leading edge of the sheet S4 and the trailing edge of the sheet S2 is within the predetermined distance L2 by the transport control unit 308, the lower discharge transport downstream clutch 332 is released by the sheet stop control unit 321 in step S414. To do. Then, the lower discharge conveyance downstream roller 121 is rotated, and the conveyance of the sheet S2 is restarted so that the sheets S4 and S2 do not come into contact with each other. Further, the escape transport downstream clutch 333 is released in accordance with the release of the lower discharge transport downstream clutch 332 so that the sheet S2 and the sheet S1 overlap at the lower discharge merge point 113. In the present embodiment, in consideration of the response time of the lower discharge conveyance downstream clutch 332, when the distance between the front end of the sheet S4 and the rear end of the sheet S2 is within 20 mm, it is determined that the distance is within the predetermined distance L2. .. FIG. 14B is a diagram in which the conveyance of the sheets S1 and S2 is restarted so that the sheets S4 and S2 do not come into contact with each other. After that, the sheet S3 and the sheet S4 are conveyed so as to overlap each other at the lower discharge merge point 113, and are sent to the post-processing unit 211.

Next, the conveyance control of the fifth and subsequent sheets of the bundle will be described. In step S411, when the transport control unit 308 determines that the sheet is the fifth or subsequent sheet, the discharge path switching control unit 320 switches the discharge transport switching flapper 102 and sends the sheet to the lower discharge transport path 110 in step S415. Then, it is sent to the post-processing unit without being stopped in the lower discharge transport path 110. FIG. 14C shows the position when the fifth sheet S5 of the bundle is being conveyed to the lower discharge conveying path 110. The sixth and subsequent sheets are also sent to the lower discharge transport path 110, similarly to the sheet S5.

By carrying the sheet in this manner, the time from the stop of the sheet S1 in the retracted conveying path 111 to the arrival of the leading edge of the sheet S4 at the trailing edge of the sheet S2 existing in the lower discharge conveying path 110 is advanced. The bundle can be assigned post-treatment time. When the third bundle of post-processing sheets is to be received subsequently to the second bundle, each sheet is sent to the post-processing unit 211 according to the flowchart of FIG.

As described above, according to the present invention, in a configuration in which sheets that have passed through different conveyance paths are merged and post-processing is performed on a plurality of stacked sheets, the time that can be post-processed without decreasing productivity is increased. It becomes possible.

In other words, in this embodiment, the control means (303) stops the first and second sheets before the front end of the fourth sheet (S4) reaches the rear end of the second sheet. It can be said that the first and second sheet conveying means are controlled so as to cancel the above.

Further, in the present embodiment, the case where the fourth sheet reaches the trailing edge of the second sheet has been described, but depending on the device configuration, the third sheet may reach the trailing edge of the first sheet first. is there. In the case of such a configuration, S413 and S414 in the flow of FIG. 13 are set as the process subsequent to S410, and the same effect can be obtained by targeting the process of S413 for the first and third sheets.

In addition, in the above-described embodiment, the example in which the lower discharge conveyance upstream roller 120, the lower discharge conveyance downstream roller 121, the escape conveyance upstream roller 122, and the escape conveyance downstream roller 123 are the same drive source has been described. However, the configuration is not limited to these. For example, the lower discharge transport upstream roller 120 and the lower discharge transport downstream roller 121, and the standby transport upstream roller 122 and the standby transport downstream roller 123 may be driven by independent motors. Then, the two sheets may be overlapped by individually setting the respective speeds. A control block diagram in this case is shown in FIG. In FIG. 15, an evacuation conveyance section conveyance motor controller 413 and an evacuation conveyance section conveyance motor 430 are provided to drive the evacuation conveyance upstream roller 122 and the evacuation conveyance downstream roller 123. The description of the other configurations is the same as in FIG. In the present configuration, the retracting conveyance section conveying motor is configured such that the sheet conveying speeds of the retracting conveying upstream roller 122 and the retracting conveying downstream roller 123 are slower than the sheet conveying speeds of the lower ejecting conveying upstream roller 120 and the lower ejecting conveying downstream roller 121. The speed of 430 is controlled. Therefore, the two sheets overlap at the lower discharge confluence point 113.

Further, for example, in the case where all the rollers are driven by different drive sources, the drive source of the standby transport downstream roller 123 is stopped without using the standby transport downstream clutch 333, so that the sheet S1 in the standby transport path 111 is stopped. May be stopped. The sheet S2 may be stopped in the lower discharge transport path 110 by stopping the drive source of the lower discharge transport downstream roller 121 without using the lower discharge transport downstream clutch 332. Further, in the embodiment in which the sheet conveyance can be independently controlled in the lower discharge conveyance path 110 and the retract conveyance path 111, each conveyance is performed according to the difference in the conveyance speed caused by the abrasion in each conveyance path 110, 111. The conveying speed of the sheets in the paths 110 and 111 may be changed. In this case, it is not necessary to disperse the sheet in each of the transport paths 110 and 111.

Further, in the above-described embodiment, the image forming system that forms an image by the electrophotographic method has been described as an example, but the present invention is not limited to this, and an image forming system that forms an image by the inkjet method can be used. The present invention may be applied. Further, although the present invention has been described by taking the example in which the sheet processing apparatus controller 303 controls the sheet processing apparatus 100, a part or all of the present invention may be controlled by the controller on the image forming apparatus 1 side. That is, in the present embodiment, the control unit, whether on the sheet processing apparatus 100 side or the image forming apparatus 1 side, controls the sheet processing apparatus side controller and the image forming apparatus side controller in cooperation. Means may be configured. Furthermore, the above-described embodiments may be combined in any way.

104: Sheet Supporting Means (Lower Discharge Tray), 110: First Sheet Conveying Path (Lower Discharging Conveying Path), 111: Second Sheet Conveying Path (Retracting Conveying Path), 113: Merging Section (Lower Discharging Converging Point) , 114: branching portion, 211: sheet processing means (post-processing unit), S1: first sheet, S2: second sheet

Claims (18)

Sheet supporting means for supporting the discharged sheet,
Sheet processing means for processing a sheet bundle consisting of a plurality of sheets discharged onto the sheet supporting means,
A first sheet conveying path for guiding a sheet to the sheet supporting means,
The first sheet conveying path is branched from the first sheet conveying path at a branch portion on the first sheet conveying path, and the first sheet conveying path is formed at a confluence portion upstream of a sheet discharging direction to the sheet supporting unit in the sheet conveying direction. A second sheet transport path that merges with
Guide means for selectively guiding the sheet to the first sheet conveying path or the second sheet conveying path at the branch portion;
A control means for controlling the guide means,
The control means, the guide means,
The first sheet that is first conveyed in the sheet bundle processed by the sheet processing unit is guided to the second sheet conveyance path, and the second sheet that follows the first sheet is the first sheet. Guiding the sheet to the sheet conveying path, and merging the first and second sheets in a manner to overlap each other at the merging portion, and
Controlling so that at least one of the sheets subsequent to the second sheet of the plurality of sheets forming the sheet bundle is guided to the second sheet transport path,
A sheet processing apparatus characterized by the above. With respect to a sheet subsequent to the second sheet among the plurality of sheets forming the sheet bundle, the control unit sets the first sheet transport path and the second sheet transport path for each unit number of sheets. , The guide means is controlled so as to be alternately guided to,
The sheet processing apparatus according to claim 1, wherein: The control means controls the guiding means so as to guide the final sheet among the plurality of sheets forming the sheet bundle to the first sheet conveying path,
The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is a sheet processing apparatus. The sheet processing means applies a sheet bundle on the sheet supporting means to the sheet bundle when the leading edge of the sheet guided by the second sheet conveyance path among the sheets following the second sheet reaches the branch portion. In contrast, it is in a non-processed state that has not been processed,
4. The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is a sheet processing apparatus. The control means has a magnitude relation between the number of sheets sent to the first sheet transport path and the number of sheets sent to the second sheet transport path out of the total number of sheets transported in the inputted sheet processing job. Controlling the guiding means to balance
The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is a sheet processing apparatus. A path length of the second sheet conveyance path between the branch section and the merging section is longer than a path length of the first sheet conveyance path,
The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is a sheet processing apparatus. A first sheet conveying means for conveying a sheet in the first sheet conveying path;
A second sheet conveying unit that conveys a sheet in the second sheet conveying path and can be driven independently of the first sheet conveying unit;
7. The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is a sheet processing apparatus. The control means controls the first and second sheet conveying means so that the sheet conveying speed in the second sheet conveying path becomes slower than the sheet conveying speed in the first sheet conveying path. To control the
The sheet processing apparatus according to claim 7, wherein: The control unit controls the second sheet conveying unit to temporarily stop the sheet in the second sheet conveying path.
The sheet processing apparatus according to claim 7, wherein the sheet processing apparatus is a sheet processing apparatus. The control means controls the guiding means so as to guide the third sheet following the second sheet to the second sheet conveying path,
The control means temporarily stops the first sheet in the second sheet transport path, temporarily stops the second sheet in the first sheet transport path, and Controlling the first and second sheet conveying means to release the stop of the first and second sheets before the front edge reaches the rear edge of the first sheet,
The sheet processing apparatus according to claim 8 or 9, characterized in that. The control means controls the guiding means so as to guide the fourth sheet following the third sheet to the first sheet conveying path,
The control means controls the first and second sheet conveying means so as to release the stop of the first and second sheets before the front end of the fourth sheet reaches the rear end of the second sheet. To do
The sheet processing apparatus according to claim 10, wherein: Sheet supporting means for supporting the discharged sheet,
Sheet processing means for processing a sheet bundle consisting of a plurality of sheets discharged onto the sheet supporting means,
A first sheet conveying path for guiding a sheet to the sheet supporting means,
The first sheet conveying path is branched from the first sheet conveying path at a branch portion on the first sheet conveying path, and the first sheet conveying path is formed at a confluence portion upstream of a sheet discharging direction to the sheet supporting unit in the sheet conveying direction. A second sheet transport path that merges with
Guide means for selectively guiding the sheet to the first sheet conveying path or the second sheet conveying path at the branch portion;
A control means for controlling the guide means,
The control unit controls the guide unit so that the number of sheets discharged to the sheet supporting unit via the first sheet conveying path among the plurality of sheets forming the sheet bundle is increased. And the guide means so as to increase the number of sheets discharged to the sheet supporting means via the second sheet conveying path among a plurality of sheets forming the sheet bundle. A second mode for controlling and a second mode for controlling are switched for each sheet bundle and can be executed.
A sheet processing apparatus characterized by the above. The control means alternately switches the first mode and the second mode for each sheet bundle.
13. The sheet processing apparatus according to claim 12, wherein: The control unit controls the number of sheet bundles processed in the first mode and the sheet bundle processed in the second mode out of the total number of sheet bundles processed in the input sheet processing job. The mode switching is executed so that the bundle number of
The sheet processing apparatus according to claim 12, wherein the sheet processing apparatus is a sheet processing apparatus. A path length of the second sheet conveyance path between the branch section and the merging section is longer than a path length of the first sheet conveyance path,
The sheet processing apparatus according to any one of claims 12 to 14, characterized in that. In the second mode, the control unit causes the guide unit to guide at least a part of the sheets when the sheet processing unit is in a non-processing state in which the sheet bundle on the sheet supporting unit is not processed. , Guiding the sheet to the second sheet conveying path,
16. The sheet processing apparatus according to claim 12, wherein the sheet processing apparatus is a sheet processing apparatus. Sheet supporting means for supporting the discharged sheet,
Sheet processing means for processing a sheet bundle consisting of a plurality of sheets discharged onto the sheet supporting means,
A first sheet conveying path for guiding a sheet to the sheet supporting means,
The first sheet conveying path is branched from the first sheet conveying path at a branch portion on the first sheet conveying path, and the first sheet conveying path is formed at a confluence portion upstream of a sheet discharging direction to the sheet supporting unit in the sheet conveying direction. A second sheet transport path that merges with
Guide means for selectively guiding the sheet to the first sheet conveying path or the second sheet conveying path at the branch portion;
A control means for controlling the guide means,
The control means, the guide means,
The first sheet that is first conveyed in the sheet bundle processed by the sheet processing unit is guided to the second sheet conveyance path, and the first sheet of the sheet bundle that follows the first sheet is conveyed. At least one of the sheets, the leading edge of which reaches the branch portion when the sheet processing means is not processing the sheet bundle on the sheet supporting means, is the second sheet conveying path. Control to guide you to
A sheet processing apparatus characterized by the above. An image forming unit that forms an image on a sheet,
Sheet supporting means for discharging and supporting the sheet on which the image is formed by the image forming section;
Sheet processing means for processing a sheet bundle consisting of a plurality of sheets discharged onto the sheet supporting means,
A first sheet conveying path for guiding a sheet to the sheet supporting means,
The first sheet conveying path is branched from the first sheet conveying path at a branch portion on the first sheet conveying path, and the first sheet conveying path is formed at a confluence portion upstream of a sheet discharging direction to the sheet supporting unit in the sheet conveying direction. A second sheet transport path that merges with
Guide means for selectively guiding the sheet to the first sheet conveying path or the second sheet conveying path at the branch portion;
A control means for controlling the guide means,
The control means, the guide means,
The first sheet that is first conveyed in the sheet bundle processed by the sheet processing unit is guided to the second sheet conveyance path, and the second sheet that follows the first sheet is the first sheet. Guiding the sheet to the sheet conveying path, and merging the first and second sheets in a manner to overlap each other at the merging portion, and
Controlling so that at least one of the sheets subsequent to the second sheet of the plurality of sheets forming the sheet bundle is guided to the second sheet transport path,
An image forming system characterized by the above.

Images