JP2010018399A - Intermediate conveyance apparatus and image forming system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve productivity by optimizing control of sheet conveyance in an intermediate conveyance apparatus capable of superposing sheets by a superposing part and conveying the plurality of superposed sheets as one set to a subsequent post processing apparatus for applying post processing to the sheets, and an image forming system equipped with the intermediate conveyance apparatus. <P>SOLUTION: This intermediate conveyance apparatus obtains information of a time ts required from reception of a previous sheet until a next sheet can be received in the post processing apparatus C, and controls the timing for conveying the sheet to the post processing apparatus C based on the information of the obtained required time ts. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an intermediate conveyance device that superimposes a plurality of sheets conveyed from an image forming apparatus and conveys the plurality of overlapped sheets to a subsequent post-processing apparatus.

  Recently, an electrophotographic image forming apparatus has been used in the field of light printing. Further, by using an image forming apparatus provided with a post-processing apparatus that performs various post-processing, book-on-printing of a print-on-demand system that “prints as many copies as necessary when necessary” becomes possible.

  Moreover, since there is no need to raise a printing plate, which has been performed in conventional printing, great expectations are placed on the efficiency of bookbinding and cost reduction.

  The image forming system disclosed in Patent Document 1 is an apparatus that can satisfy such a requirement. A single sheet processing machine, which is a kind of post-processing apparatus, is connected to the sheet discharge unit side of the image forming apparatus, In the image forming system, at least one type of post-processing device among the types of post-processing devices is connected to a single sheet processing machine.

  Furthermore, in an image forming apparatus or an image forming system in which a post-processing apparatus is connected to the image forming apparatus, it is desired that the number of processed sheets per unit time (hereinafter referred to as productivity) is large. The demand is particularly strong in the field of light printing. In many cases, the number of processed sheets of the image forming system is determined by the capacity of the post-processing apparatus rather than the capacity of the image forming apparatus.

  That is, since the post-processing apparatus often performs processing while temporarily stopping the conveyance of the sheet, it is necessary to ensure a sufficient interval distance between successive sheets (hereinafter referred to as a sheet interval). As one means for that purpose, the conveyance speed in the post-processing apparatus is increased more than the conveyance speed in the image forming apparatus. However, with the recent increase in speed, since the transport speed of the image forming apparatus is increased, the increase in the transport speed of the post-processing apparatus is approaching its limit.

  In view of this, the image forming apparatus disclosed in Patent Document 2 discloses an apparatus in which an overlapping unit that stacks a plurality of sheets is provided in an intermediate transport unit, and a plurality of sheets stacked in the stacking unit are transported simultaneously. Yes. By transporting multiple sheets at the same time in this way, it is possible to increase the sheet interval for the number of stacked sheets without increasing the transport speed, that is, improving the productivity of the post-processing device. It becomes possible to make it.

  However, when the number of sheets in the sheet bundle to be processed by the post-processing device is small, or when inserting different types of sheets such as inserted sheets into the sheet bundle, the sheets are stacked in the overlapping unit, It cannot be transported.

In the image forming system described in Japanese Patent Laid-Open No. 2004-260260, a necessary sheet interval cannot be ensured in the overlapping unit (storage unit) under such conditions, so that the sheet conveyance from the image forming apparatus on the upstream side is not possible. By increasing the interval by the interval of one sheet or two or more sheets, it is possible to prevent the occurrence of a conveyance jam due to the interference between the preceding sheet and the succeeding sheet.
JP 2005-15225 A JP 2007-156406 A JP 2006-176306 A (particularly paragraph 0127)

  In the image forming system described in Patent Document 3, when the sheet interval cannot be secured by the overlapping unit, the sheet conveyance interval in the overlapping unit together with the upstream image forming apparatus is set as a unit of the sheet interval. , The unit was multiplied by the interval obtained by multiplying the unit by the number of overlaps in the overlap portion.

  For this reason, depending on the sheet size or the number of sheets in the sheet bundle, the sheet conveyance interval becomes longer than necessary, and as a result, a problem of significant reduction in productivity occurs.

  In view of the above problems, the present invention is an intermediate conveying device that can superimpose sheets in a superimposition unit and convey a plurality of superimposed sheets to a subsequent post-processing apparatus that performs post-processing on the sheets. An object of the present invention is to improve productivity by optimizing paper conveyance control in an image forming system including the intermediate conveyance device.

1. A plurality of sheets of paper conveyed from the image forming apparatus are overlapped and temporarily stored in the overlapping unit, and the plurality of overlapped sheets are transported to a subsequent post-processing apparatus that performs post-processing on the sheets. An intermediate transfer device capable of
Communication means for performing data communication with the image forming apparatus and the post-processing apparatus;
Control means for controlling paper conveyance, the control means,
Obtaining information on a required time ts required for receiving the next sheet in the post-processing apparatus from the communication unit until the next sheet can be received;
An intermediate conveying apparatus that controls timing of conveying a sheet to the post-processing apparatus based on the acquired information on the required time ts.

2. The control means includes
2. The intermediate conveyance according to 1, wherein control is performed so that the next sheet is conveyed to the post-processing apparatus after the required time ts has elapsed from a timing at which the sheet is conveyed to the post-processing apparatus immediately before. apparatus.

3. The control means includes
In the superimposing unit, when it is determined that the subsequent sheet conveyed from the image forming apparatus following the sheet stored in the overlapping unit cannot be received,
3. The intermediate conveying apparatus according to 2, wherein the image forming apparatus is instructed to delay a conveyance timing of the subsequent sheet.

4). The time td for delaying the conveyance timing of the succeeding paper with respect to the image forming apparatus when the continuous paper conveyance cycle from the image forming apparatus is tm, and the required time ts satisfy the following relational expression. 4. The intermediate transfer device as described in 3 above.
td = (ts−tm) × m
(Where m is a positive integer)
5). An image forming apparatus for forming an image on paper;
An aftertreatment device;
A plurality of sheets conveyed from the image forming apparatus are overlapped and temporarily stored in an overlapping portion, and the plurality of overlapped sheets are transported to a subsequent post-processing apparatus that performs post-processing on the sheets. The intermediate transfer device according to any one of the above 1 to 4,
An image forming system comprising:

According to the present invention, in the post-processing apparatus, information on the required time ts required from when the previous sheet is received until the next sheet can be received is acquired,
An intermediate transport device that can improve productivity by controlling the timing of transporting the sheet to the post-processing device based on the acquired information on the required time ts, and an image including the intermediate transport device A forming system can be provided.

  Although the present invention will be described based on an embodiment, the present invention is not limited to the embodiment.

  FIG. 1 is an overall configuration diagram of an image forming system having an image forming apparatus A, an intermediate conveying apparatus B, and a post-processing apparatus C. The intermediate conveyance device B is connected between the image forming apparatus A and the post-processing apparatus C.

[Image forming apparatus A]
The image forming apparatus A has an automatic document feeder 1 and an image reading unit 2 in the upper part, and the lower part is composed of a printer unit.

  In the printer section, 3 is a paper storage section for storing the paper S. An image is formed on the paper S in the image forming unit 5 that forms a toner image on the photoconductor 4 by an electrophotographic process in which the photoconductor 4 is charged, exposed, and developed, and the formed image is a fixing device. 6 is fixed. The fixing device 6 forms a nip for transporting the paper S by the heating roller 6b and the pressure roller 6c. The heating roller 6b includes a heat source 6a, and controls the heating roller 6b to a constant temperature by controlling the amount of heat generated by the heat source by a temperature sensor (not shown). While the sheet S is conveyed to the nip of the fixing device 6, the toner is melted by heating and pressing to fix the toner image on the sheet S.

  The sheet S is fed from the sheet storage unit 3 by the first sheet feeding unit 3a, and after being temporarily stopped by the second sheet feeding unit 3b, the sheet is fed and image formation is performed. The paper is discharged from the paper discharge port by the roller 8.

  As the transport path of the paper S, a paper feed path 7 from the paper storage unit 3 to the image forming unit 5, a transport path 9 a from the image forming unit 5 through the fixing device 6 and the paper discharge roller 8 to the paper discharge port and image formation. A double-sided conveyance path 9 b is provided for reversing the cover sheet, switching it back and conveying it to the paper feed path 7 again.

  Reference numeral tp denotes an operation display unit, which includes a touch panel in which a touch screen is arranged on a display unit constituted by a liquid crystal panel. Various modes in the image forming apparatus A and an output mode using the post-processing apparatus C can be set by an operation on the operation display unit tp.

  The sheet S discharged from the image forming apparatus A is conveyed to the post-processing apparatus C via the intermediate conveying apparatus B.

[Intermediate transfer device B]
The intermediate conveyance device B includes a paper carry-in unit 11, a stacking unit 12, a paper carry-out unit 13, and a bypass conveyance unit 14. The intermediate conveying apparatus B is independent of the image forming apparatus A and the post-processing apparatus C, and can perform a printing operation only with the configuration of the image forming apparatus A and the post-processing apparatus C. It can be added later to the image forming system including the image forming apparatus A and the post-processing apparatus C for the purpose of improving the productivity of the post-processing apparatus. In the intermediate conveyance device B, a plurality of sheets conveyed from the image forming apparatus A can be stacked by the overlapping unit 12, and the plurality of sheets are stacked as a set to the subsequent post-processing apparatus C. Can be transported. Details of the intermediate transfer device B will be described later.

[Post-processing device C]
The post-processing apparatus C superimposes a plurality of sheets discharged from the image forming apparatus A by the intermediate conveyance apparatus B to form a set of sheets, and performs various types of post-processing on the sheets S conveyed as the set of sheets. It is a general term for punching machines, folding machines, flat stitching machines, center folding and saddle stitching machines, gluing bookbinding machines, cutting machines and the like. Hereinafter, a staple device will be described as an example of the post-processing device C.

  In the post-processing apparatus C, from the upper part of the figure, the insertion sheet feeding means 40, the shift means 20, the processing tray 30, and the staple unit 50, which store insertion sheets (used for front cover, back cover, etc.), are substantially vertical. It is arranged in a column in the direction.

  In the processing tray 30, a plurality of sheets S on which images are formed by the image forming apparatus A are temporarily placed to create a sheet bundle. The paper placed on the processing tray 30 is subjected to vertical alignment in the transport direction and width alignment perpendicular to the vertical direction, and then the stapling process is performed on the paper bundle by the staple unit 50.

  The shift unit 20 performs a shift process for changing the paper discharge position in the transport width direction for each predetermined number of sheets on the image-formed paper discharged from the image forming apparatus A.

  An inlet conveyance unit 70 is disposed at the upper right of the sheet post-processing apparatus C in the figure. In addition, on the left side of the sheet post-processing apparatus C in the figure, a movable sheet discharge tray 81 for discharging and stacking sheets on which images are formed is disposed.

  FIG. 2 is a block diagram of a control system in the image forming system. In the figure, the periphery of the part necessary for the description of the operation of the present embodiment is mainly described, and other parts known as the image forming system are omitted. Further, in the following drawings, in order to avoid duplication of explanation, common portions are denoted by the same reference numerals and replaced with explanation.

  In the intermediate transfer device B, reference numeral 100B denotes a CPU which executes various controls of the intermediate transfer device B according to a program. A ROM 101B stores various programs and data including programs and data for controlling the intermediate transfer device B. A RAM 102B is used as a work area by the CPU 100B, and temporarily stores programs and data required when the CPU 100B executes control of the intermediate conveyance device B.

  Then, the CPU 100B functions as a control unit and executes control of the intermediate transfer device B based on programs and data developed in the RAM 102B.

  A communication unit 103B functions as a communication unit, and is connected to the communication unit 103A of the image forming apparatus A and the communication unit 103C of the post-processing apparatus C. Various data such as the size information of the paper conveyed from the image forming apparatus, the number of output sheets, and post-processing information are transmitted to and received from the image forming apparatus A. Reference numeral 104B denotes a bus, and the ROM 101B, the RAM 102B, the communication unit 103B, and the like are connected to each other. Reference numeral 105B denotes a conveyance unit that conveys paper by controlling operations of a drive motor, a conveyance path switching solenoid, and the like.

  100A to 105A of image forming apparatus A and 100C to 105C of post-processing apparatus C correspond to 100B to 105B of intermediate conveyance apparatus B, respectively, and have similar functions.

[Intermediate transfer device B]
Based on FIG. 3 and FIG. 4, the sheet superposition operation in the intermediate conveyance device B will be described. FIG. 3 is a front cross-sectional view of the intermediate transfer device B, and FIG. 4 is a cross-sectional view showing driving means around the overlapping portion 12 of the intermediate transfer device B.

  As described above, the intermediate conveyance device B includes the paper carry-in unit 11, the stacking unit 12, the paper carry-out unit 13, and the bypass conveyance unit 14.

  The paper carry-in unit 11 includes a paper conveyance path r11 having conveyance rollers R1 and R2 and a guide plate 111. In the paper carry-in unit 11, the paper S discharged from the paper discharge unit 5E of the image forming apparatus A is sequentially received and conveyed.

  The overlapping portion 12 includes two guide plates 121 arranged in parallel, a vertical alignment portion having a stop member 123 and a vertical alignment member 124, a horizontal alignment member 122, a carry-in drive roller R3, a carry-out drive roller R4, and a sheet. A conveyance path r12 is provided. In the stacking unit 12, the plurality of sheets S carried in from the sheet carry-in unit 11 are stored and aligned in a stacked state, and then discharged upward.

  The sheet carry-out section 13 includes a sheet conveyance path r13 having an intermediate conveyance roller R5, a discharge roller pair (conveyance roller pair) R6 and R7, and a guide plate 131. In the paper carry-out unit 13, the plurality of sheets S stored in the superimposing unit 12 are reversed and conveyed while being superimposed, and conveyed to the subsequent post-processing device C.

  The bypass transport unit 14 includes a paper transport path r14. The conveyance of the sheet to the bypass conveyance unit 14 is performed when it is not necessary to convey the sheet to the overlapping unit 12. For example, there is a case where post-processing of the paper is unnecessary, or a case where the paper is transported with a wide setting between the papers, such as not continuous printing.

  The conveyance path switching unit G2 disposed in the paper carry-in unit 11 is branched to either the bypass conveyance path 14 or the overlapping unit 12. A transport path switching unit G1 is disposed above the overlapping unit 12. The conveyance path switching unit G <b> 1 switches between introduction of the paper S into the superposition unit 12 and discharge of the paper S from the superposition unit 12. The transport path switching units G1 and G2 are each connected to a solenoid and driven.

  FIG. 4 is a cross-sectional view showing driving means around the overlapping portion 12 of the intermediate transfer device B. The conveyance path switching unit G2 that supports the carry-in driven roller R10 and the carry-out driven roller R11 is driven and swung by the solenoid SOL1. The carry-in drive roller R3 is driven by the solenoid SOL2 to open and close the paper transport path r11. The vertical alignment member 124 is driven to swing by the solenoid SOL3.

  The motor M1 drives and rotates the conveying roller R2, and rotates the carry-in driving roller R3 via the belt. The motor M2 drives and rotates the carry-out driving roller R4.

  The stop member 123 is locked to the belt 125 rotated by the motor M3, and is guided up and down by the guide bar 126. Depending on the length of the transported paper in the transport direction, the standby position when preparing to receive the stop member varies. The stop member 123 is kept waiting at the lower position as shown in FIG. 3 and a plurality of sheets are received in this state, and the horizontal alignment member 122, the vertical alignment member 124, and the stop surface portion 123A of the stop member 123 are aligned vertically and horizontally. .

  As shown in FIG. 4, after the alignment, the stop member is raised, and a plurality of sheets of paper as a set are brought into contact with the carry-out driving roller R4 and the carry-out driven roller R11. Then, the upper ends of S1 and S2 are sandwiched. The vertical alignment member 124 is retracted from the paper transport path r13 by driving a solenoid (not shown). Due to the drive rotation of the carry-out drive roller R4, the pair of sheets S1 and S2 sandwiched between the carry-out drive roller R4 and the carry-out driven roller R11 are conveyed to the sheet carry-out unit 13, and are further sandwiched by the intermediate conveyance roller R5. To the post-processing apparatus C.

  As described above, two or more sheets S are reversed in a state of being overlapped via the overlapping portion 12 of the intermediate conveying device B, and discharged to the subsequent post-processing portion C. The stagnation time of the paper reversal conveyance is unnecessary, and the reversal conveyance can be performed quickly.

  Note that the number of sheets S stored in the stacking unit 12 is not limited to two, and three or more sheets can be stacked. The number setting may be set by the control means in consideration of the post-processing setting of the subsequent post-processing apparatus C.

[Conveyance control in the first embodiment]
Based on FIG. 5 thru | or FIG. 8, the intermediate conveyance apparatus B which concerns on 1st Embodiment is demonstrated. FIG. 5 to FIG. 7 are diagrams for explaining transport control in the intermediate transport apparatus B, and FIG. 8 is a diagram showing a control flow when the intermediate transport apparatus B performs paper transport to the downstream side. Note that the control flow shown in FIG. 8 is executed by the CPU 100B functioning as control means.

  In the first embodiment, the time required from the time when the sheet of the superposition unit 12 is conveyed to the post-processing device C until the next paper can be received after the previous paper is received by the post-processing device C. This is performed in consideration of ts. In the embodiments described below, one example of the required time ts is shown for each type of post-processing. However, the present invention is not limited to this, and two types of required time ts may be set. For example, when the post-processing apparatus is a glue binding machine, one sheet (one book) of the last page is transported and glued to the sheet bundle to attach the cover. In such a case, “the time required to transport the paper for the last page of the copy and finish the gluing process and receive the next paper” is From the time required until the next sheet can be received, it becomes longer than the time required to set the two types of required time.

Examples and symbols for each condition are shown below. In the description of FIGS. 5 to 12, paper conveyance and post-processing are performed under the following conditions unless otherwise specified.
-Paper transport speed in intermediate transport device B: 1000 mm / s
-Paper size: A4 size lateral feed (210 mm length in the transport direction, 210 ms feed time)
-Paper feed interval tm of paper conveyed from the image forming apparatus A: 500 ms
-Required time ts in post-processing device C: 570 ms
-Number of overlapping sheets m in the overlapping section 12: 2
Further, in the diagrams illustrating the conveyance control shown in FIGS. 5 to 7, 10, and 12, the downward white arrow indicates the end of the last page of the section, that is, the section break. Further, p1 to p8 indicate sheet numbers to be conveyed.

  FIG. 5 is a diagram illustrating the conveyance control of the image forming system according to the present embodiment. The example shown in the figure is an example in which a stapling process is performed on a part of two sheets, and a total of six sheets are continuously conveyed to create a booklet of three copies.

  In the example shown in the figure, all the sheets conveyed from the image forming apparatus A are overlapped by the overlapping unit 12 two by two and then transported to the post-processing apparatus C as a set of two sheets. . For this reason, the receiving interval tc in the post-processing apparatus C is 1000 ms, which is twice the feeding interval tm from the image forming apparatus A. In this case, since the receiving interval tc> the post-processing required time ts, it is not necessary to control the timing for conveying the paper to the post-processing apparatus C by the control unit. In the example of FIG. 5, (1) the control according to the present embodiment as an example and (2) the conventional control as a comparative example are the same control operation.

  FIG. 6 is a diagram illustrating conveyance control in conventional control of an image forming system as a comparative example. The example shown in the figure is an example in which a stapling process is performed on a part of three sheets, and a total of six sheets are continuously conveyed to create two copies of a booklet.

  In the example shown in the figure, since the third sheet is a sheet that is not overlapped at the division, when the sheet is conveyed as it is, the first set is processed by the post-processing apparatus C. Since the required time ts of the post-processing apparatus cannot be ensured after being transported, the timing of transporting the third sheet to the post-processing apparatus C is delayed by the sheet feeding interval tm for one sheet. With this process, the time for the third sheet to stay in the stacking unit 12 becomes longer, so it is not possible to secure the timing for receiving the next fourth sheet. For this reason, the timing for conveying the fourth sheet from the image forming apparatus A to the intermediate conveying apparatus B is also delayed by the sheet feeding interval tm for one sheet. In the comparative example shown in FIG. 6, although the control is simple, it can be seen that the sheet conveyance interval becomes longer than necessary, and the productivity is reduced by 25%.

  FIG. 7 is a diagram illustrating conveyance control of the image forming system according to the present embodiment. The example shown in FIG. 6 is an example in which a stapling process is performed on a part of three sheets and a total of six sheets are continuously conveyed to create a two-part booklet, as in FIG.

  In the example shown in the figure, information on the required time ts required from when the previous sheet is received until the next sheet can be received is acquired, and the post-processing device is based on the acquired information on the required time ts. Since the timing of transporting the paper to the head is controlled, a reduction in productivity can be minimized. Hereinafter, a description will be given with reference to FIGS.

[Control flow]
First, in step S11 of FIG. 8, information on the required time ts in the post-processing device corresponding to the type of post-processing performed in the post-processing device C is acquired. The information is acquired by transmission via the communication unit 103B and the communication unit 103C (step S31). The correspondence relationship between the type of post-processing and the required time ts is stored as a table value in the image forming apparatus A, and the post-processing required time ts is transmitted from the image forming apparatus A to the intermediate conveyance device B. May be.

  In step S12, the timer tw is initialized.

  In step S13, if there is no operation stop request from the image forming apparatus A (step S13: No), the sheet is stored in the overlapping unit 12 in step S14.

  In step S15, when there is a request for feeding the succeeding sheet (step S15: Yes), and in step S16, there is an overlap with the succeeding sheet (step S16: Yes), the control flow after step S13 is executed. repeat.

  On the other hand, if there is no request for feeding the succeeding sheet (sixth sheet in the example of FIG. 7) or if there is no overlap with the succeeding sheet (second sheet, 3, 5, 6 in the example of FIG. 7), the following steps In S17, it is determined whether or not the timer tw is 0.

  If the timer tw is not 0 (step S17: No), the determinations in steps S15 and S16 are repeated, and the process continues to wait until the timer tw becomes 0.

  On the other hand, if the timer tw is 0 (step S17: Yes), the paper stored in the overlapping unit 12 is conveyed to the post-processing apparatus C in step S18. In the post-processing apparatus C, post-processing is performed on the conveyed paper.

  In the intermediate transfer device B, the required time ts acquired in step S11 is set in the timer tw in the timer tw.

  In step S20, the timer tw starts to count down immediately. Thereafter, by carrying out the processing after step S13, the paper can be efficiently conveyed by controlling the paper conveyance timing with the timer tw. In the example shown in FIG. 7, for the third sheet (the same applies to the sixth sheet), after the first sheet and the second sheet are paired as a set from the superposition unit 12 in step S18, the sheet is conveyed to the post-processing device. In step S17, since the timer tw is not 0, after waiting for 70 ms from the third sheet (p3) being loaded into the superimposing unit 12 until the sheet is unloaded, the sheet is conveyed to the post-processing apparatus C. It is carried out. Since the waiting time is optimized according to the required time ts, it can be seen that the embodiment shown in FIG. 7 has higher productivity than the comparative example shown in FIG.

  According to the present embodiment, information on the required time ts required from when the previous paper is received until the next paper can be received is acquired, and based on the acquired information on the required time ts, the information is sent to the post-processing device. By controlling the timing of transporting the paper, it is possible to optimize the control of paper transport and improve productivity.

[Conveyance control in the second embodiment]
Based on FIG. 9 thru | or FIG. 12, the intermediate conveyance apparatus B which concerns on 2nd Embodiment is demonstrated. FIG. 9 is a diagram illustrating a control flow when the sheet is received from the upstream side in the intermediate conveyance device B. The control flow shown in FIG. 9 is executed by the CPU 100B functioning as a control unit. FIG. 10 is a diagram illustrating conveyance control of the image forming system according to the present embodiment. FIG. 10 shows an example in which the stapling process is performed on a part of the top three sheets, the subsequent five sheets are shifted one by one, and a total of eight sheets are continuously conveyed.

  FIGS. 11 and 12 are modifications of FIGS. 9 and 10, respectively. FIGS. 9 and 10 are examples in which the coefficient m (described later) is 3, and FIGS. 11 and 12 are cases in which the coefficient m is 2. It is an example.

  In the second embodiment, in addition to the control in the first embodiment, it is not possible to secure a time for receiving a subsequent sheet conveyed following the sheet stored in the overlapping unit 12, that is, “determined that it cannot be received”. In this case, the image forming apparatus A is controlled to delay the conveyance timing of the subsequent sheet. This will be described below.

  In step S51 in FIG. 9, the counter C is reset. In step S52, if there is no paper feed request, the control ends. The counter C is a counter of the number of times that sheets discharged one by one without overlapping are continuous.

  On the other hand, if there is a paper feed request (step S52: No), in the subsequent step S53, the required time ts of the post-processing apparatus according to the type of post-processing performed by the post-processing apparatus C, and the supply from the image forming apparatus A Information on the paper interval tm is acquired. Acquisition of information is performed by transmission via the communication unit 103B and the communication unit 103A, and the communication unit 103B and the communication unit 103C. The image forming apparatus A stores the correspondence relationship between the type of post-processing, the required time ts, and the paper feeding interval tm according to the paper size and mode as a table value. These pieces of information may be collectively transmitted to the intermediate transfer apparatus B.

  In step S54, it is determined whether or not there is an overlap with the preceding paper. In the example shown in FIG. 10 (also in FIG. 12), it is determined that there is an overlap with the preceding paper in the second sheet (step S54: Yes), and the other sheets are overlapped with the preceding sheet. It is determined that there is not (step S54: No).

  In step S55, the counter C is incremented. In step S56, it is determined whether the counter C has reached 3. If it is determined that C is not 3 (step S56: No), the flow after step S52 is repeated. The reason why C = 3 will be described. In the present embodiment, as described above, the number of superimposed images in the overlapping unit 12 is two. Discharge (hereinafter referred to as 1 sheet discharge) with less than the number of overlapped sheets (hereinafter referred to as 1 sheet discharge) can absorb the delay in the next overlap, but if it continues twice, the next overlap process alone This is because the delay cannot be absorbed. C is a counter indicating the number of times one sheet is continuously discharged. By setting C = 3, it is determined whether or not the sheet corresponds to the next continuous sheet twice.

  In the example shown in FIG. 10, the counter C is continuously incremented for the third and subsequent sheets, and it is determined that C = 3 for the fifth sheet (step S56: Yes).

In the subsequent step S57, a delay time td for delaying the timing for conveying the fifth sheet from the image forming apparatus A is calculated based on the following equation.
Delay time td = (ts−tm) × m
However, m is a positive integer.

  In the example shown in FIG. 10, m = 3. In this case, td = (570−500) × 3 = 210 ms. In the case of m = 2 shown in FIG. 12, td = 140 ms. In this embodiment, the increase / decrease of the delay time is set to 70 ms (= 570−500) units. This is because if it is 80 ms or longer, in order to avoid a collision between the discharged sheet and the received sheet in the overlapping section 12, the sheet feeding must be delayed after the discharging of one sheet. Because. If it is 70 ms or less, such a problem does not occur.

  In step S58, the delay time td and the delay instruction calculated in step S57 are transmitted to the image forming apparatus A via the communication unit 103B.

  In step S59, the counter C is reset, and the flow after step S52 is repeated.

  On the other hand, the image forming apparatus A receives the delay instruction and the delay time td from the intermediate transport apparatus B in step S61. In the next step S62, the next sheet (fifth sheet in the example of FIG. 10) is conveyed to the intermediate conveying device B based on the information received in step S61 with a delay time td.

  In the fifth and eighth sheets in FIG. 10, td is 210 ms as described above, so that the intermediate from the image forming apparatus A is spaced by 710 ms (= 500 + 210) obtained by adding the delay time td to the normal sheet feeding interval tm. Transport to the transport device B is performed. Similarly, in the fourth and seventh sheets in FIG. 12, td is 140 ms, so that the interval from the image forming apparatus A is 640 ms (= 500 + 140) obtained by adding the delay time td to the normal sheet feeding interval tm. Transport to the transport device B is performed.

  As shown in FIGS. 10 and 12, the sheet conveyance from the stacking unit 12 to the post-processing apparatus C is performed at an interval of the required time ts (= 570 ms) or more. There is no problem with post-processing. As shown in FIG. 10, the discharge delay process is performed with a delay time of 140 ms for the third sheet (p3) and a delay time of 140 ms for the fourth sheet (p4) together with the delay time for the third sheet.

  In the example of m = 3 shown in FIG. 10, delay processing is performed when sheets discharged in one sheet are generated three times in succession without overlapping. In the case of FIG. 12, since m = 2, a delay process is performed every time two consecutive occurrences occur.

  According to the present embodiment, the superimposing unit 12 performs control so that the next sheet is conveyed to the post-processing device after the required time ts has elapsed from the timing at which the sheet was conveyed to the post-processing device immediately before. If it is determined that it is not possible to secure a time for receiving the succeeding sheet transported from the image forming apparatus following the sheet stored in the superimposing unit 12, the timing of transporting the succeeding sheet to the image forming apparatus is determined. By instructing to delay the post-processing, it becomes possible to minimize the delay in conveyance from the image forming apparatus, and to maintain the productivity to the maximum extent within the range in which the post-processing apparatus C does not interfere with the post-processing. Is possible.

1 is an overall configuration diagram of an image forming system having an image forming apparatus A, an intermediate conveying apparatus B, and a post-processing apparatus C. FIG. 2 is a block diagram of a control system in the image forming system. FIG. 4 is a front sectional view of an intermediate transfer device B. FIG. FIG. 6 is a cross-sectional view showing driving means around the overlapping portion 12 of the intermediate transfer device B. It is a figure explaining conveyance control of the image forming system concerning this embodiment. It is a figure explaining conveyance control in conventional control of an image forming system as a comparative example. It is a figure explaining conveyance control of the image forming system concerning this embodiment. FIG. 6 is a diagram illustrating a control flow when paper is conveyed downstream in the intermediate conveyance device B. FIG. 6 is a diagram illustrating a control flow when paper is received from the upstream side in the intermediate conveyance device B. It is a figure explaining conveyance control of the image forming system concerning this embodiment. It is a modification of FIG. It is a modification of FIG.

Explanation of symbols

A Image forming apparatus 5 Image forming section B Intermediate transport apparatus 11 Paper carry-in section 12 Overlap section 122 Horizontal alignment member 123 Stop member 124 Vertical alignment member 13 Paper carry-out section 14 Bypass transport section 100B CPU
101B ROM
102B RAM
103B Communication unit C Post-processing device 50 Stapling unit

Claims (5)

A plurality of sheets of paper conveyed from the image forming apparatus are overlapped and temporarily stored in the overlapping unit, and the plurality of overlapped sheets are transported to a subsequent post-processing apparatus that performs post-processing on the sheets. An intermediate transfer device capable of
Communication means for performing data communication with the image forming apparatus and the post-processing apparatus;
Control means for controlling paper conveyance, the control means,
Obtaining information on a required time ts required for receiving the next sheet in the post-processing apparatus from the communication unit until the next sheet can be received;
An intermediate conveying apparatus that controls timing of conveying a sheet to the post-processing apparatus based on the acquired information on the required time ts. The control means includes
2. The intermediate according to claim 1, wherein control is performed so that the next sheet is conveyed to the post-processing apparatus after the required time ts has elapsed from a timing at which the sheet is conveyed to the post-processing apparatus immediately before. Conveying device. The control means includes
In the superimposing unit, when it is determined that the subsequent sheet conveyed from the image forming apparatus following the sheet stored in the overlapping unit cannot be received,
The intermediate transport apparatus according to claim 2, wherein the image forming apparatus is instructed to delay a transport timing of the subsequent sheet. The time td for delaying the conveyance timing of the succeeding paper with respect to the image forming apparatus when the continuous paper conveyance cycle from the image forming apparatus is tm, and the required time ts satisfy the following relational expression. The intermediate transfer apparatus according to claim 3.
td = (ts−tm) × m
(Where m is a positive integer) An image forming apparatus for forming an image on paper;
An aftertreatment device;
A plurality of sheets conveyed from the image forming apparatus are overlapped and temporarily stored in an overlapping portion, and the plurality of overlapped sheets are transported to a subsequent post-processing apparatus that performs post-processing on the sheets. The intermediate transfer device according to any one of claims 1 to 4,
An image forming system comprising:

Images