JP2006137570A - Synchronous conveyance method, sheet conveyance device, and image forming system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent occurrence of breakage and jam of a sheet by loosening and pulling-out of the sheet due to difference in conveyance speed. <P>SOLUTION: This sheet conveyance device checks whether a deceleration timing signal is received during paper conveyance (S201) or not (S202) and decelerates a conveyance driving motor when receiving the deceleration timing signal. This deceleration timing signal is transmitted from a paper post-processing device. When the conveyance driving motor is stopped or is decelerated to indicated speed (S204), this sheet conveyance device waits for inputting of an acceleration timing signal. When receiving the acceleration timing signal transmitted from the paper post-processing device (S205), this device repeats a cycle in which the conveyance driving motor 370 is accelerated (S206) and operation returns to step S201 to check whether a paper is being conveyed or not upon completion of acceleration (S207). Consequently, acceleration and deceleration of the paper post-processing device and acceleration and deceleration of a mail box are performed in synchronization to convey a paper. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a synchronous conveyance method in which sheet conveyance is performed in synchronization between a plurality of units such as independent paper discharge devices, stacking devices, and sorting devices, and sheet conveyance in which sheet conveyance is performed between the plurality of units in synchronization. The present invention relates to an apparatus and an image forming system that includes the sheet conveying apparatus and conveys a sheet discharged from the image forming apparatus in synchronization with a desired unit such as a processing apparatus or a mailbox.

  As this type of technology, for example, the invention described in Patent Document 1 or 2 is known. Among these, Patent Document 1 discloses a sheet processing apparatus provided in a sheet post-processing apparatus including a sheet processing station including a stack sheet binding processing unit and a sheet stacking unit. A plurality of upper and lower trays, a sheet conveying means for selectively conveying sheets to a predetermined tray, and a sheet introduced into a sheet post-processing apparatus. There is disclosed a paper processing apparatus comprising a paper introducing means for taking in the means.

Further, Patent Document 2 has a plurality of units divided for each function such as a paper feed unit, a finisher unit, a duplex unit, and the like, and image formation in which the plurality of units can be replaced for each unit. In the apparatus, jam detecting means for detecting the occurrence of jam in each of the plurality of units, and jam information storing means for storing the jam occurrence history of the unit whose occurrence of jam is detected by the jam detecting means as jam history information for each unit. When jam occurrence is detected by the jam detection means, the jam history information of the unit in which the occurrence of the jam is detected is extracted from the jam information storage means, and there is a unit in which the occurrence of the jam is detected and Display means for displaying the jam history information, and stored in the jam information storage means Deleting means for deleting the jam history information for each unit, wherein the deleting means is based on the display by the display means, when the unit in which the occurrence of the jam is detected is replaced, An image forming apparatus is disclosed in which jam history information relating to the replaced unit is deleted from a jam information storage unit.
JP 2000-189033 A JP 2003-122198 A

  When multiple units such as a paper post-processing device and an independent paper discharge device, stacking device, and sorting device that can be selectively installed on the downstream side of this paper post-processing device are installed, punching, binding, and bookbinding of paper In the process of performing post-processing such as sorting, in the process of performing each process on the paper, if the transport speed between the two units delivering the paper is different, such as between the paper post-processing device and each unit, Due to the difference in speed between the processing unit and each unit, the paper is slackened or pulled, and the paper is damaged or the paper is jammed due to the slack or pulling of the paper.

  The present invention has been made in view of such a background, and an object thereof is to prevent a sheet from being damaged or jammed due to sheet loosening or pulling due to a difference in conveying speed.

  In order to achieve the object, the first means, when transporting the sheet-like recording medium from the first device to the second device, when the transport speeds of the first and second devices are different from each other, The synchronous conveyance method which synchronizes the conveyance speed change timing is characterized.

  The second means is the sheet processing apparatus according to the first means, which performs a predetermined process on the sheet-like recording medium into which the first apparatus has been carried.

  A third means is a mail box according to the second means, wherein the second apparatus sorts the sheets discharged from the sheet processing apparatus.

  In a sheet conveying apparatus that conveys a sheet between a plurality of units, the fourth means is configured to synchronize the change timings of the respective conveying speeds when the conveying speeds of the two units that deliver the sheets are different from each other. It has the means to convey.

  A fifth means is characterized in that, in the fourth means, the change timing of the conveyance speed includes one of acceleration / deceleration timing and start / stop timing.

  Sixth means is characterized in that, in the fourth or fifth means, when the sheet straddles the transport driving system of the two units, the transporting means synchronizes the change timings of the respective transport speeds. To do.

  The seventh means is any one of the fourth to sixth means, wherein the conveying means conveys the acceleration / deceleration between the two units, the acceleration / deceleration at the time of starting and stopping, and the acceleration / deceleration distance as equal. It is characterized by.

  The eighth means is any one of the fourth to seventh means, wherein the transport means changes the transport speed based on a timing signal transmitted and received between the two units when the transport speed is changed. And the timing to synchronize is set.

  A ninth means is characterized in that, in the eighth means, the transmission side of the conveyance speed change timing signal transmits the timing signal while shifting the signal transmission delay time.

  The tenth means includes a detecting means in any one of the fourth to ninth means, wherein the upstream unit of the two units in the sheet conveyance direction detects the conveyance of the sheet, and the unit on the downstream side of the sheet conveyance is the unit The conveyance speed change timing is determined based on a detection signal from a detection means, and the conveyance is performed in synchronization with the upstream unit.

  An eleventh means according to any one of the fourth to tenth means is characterized in that the conveying means changes the conveying speed in accordance with a sheet processing mode.

  A twelfth means is the sheet processing apparatus according to any one of the fourth to eleventh means, wherein one of the units performs a predetermined process on the sheet-like recording medium and discharges the sheet, and the other one is the sheet processing apparatus. This is a mail box provided on the downstream side in the sheet conveying direction.

  The thirteenth means includes an image forming apparatus for forming an image on a sheet, and a sheet conveying apparatus according to any of the fourth to twelfth means for conveying a sheet discharged from the image forming apparatus. Features a forming system.

  In the following embodiments, the sheet processing apparatus is the paper post-processing apparatus 200, the mail box is the reference numeral 300, the conveying means is the CPUs 291 and 350, the conveyance drive motors 2942 and 370, and each roller driven by the motor. Each corresponds. The sheet in the present invention is a general term for sheet-like recording media including paper.

  According to the present invention, when the conveyance speeds of the two units that deliver the sheets are different, the sheet-like recording medium is conveyed in synchronization with the change timings of the conveyance speeds. The sheet can be prevented from being damaged or jammed by pulling or the like.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram showing a schematic configuration of an image forming system including a sheet post-processing apparatus according to an embodiment of the present invention. In FIG. 1, the image forming system basically includes an image forming apparatus 100, a sheet post-processing apparatus 200, and a mail box 300. The paper post-processing apparatus 200 is installed on the downstream side of the image forming apparatus 100, and performs post-processing such as discharge stacking, sorting, punching (punching), binding, and bookbinding of the paper conveyed from the image forming apparatus 100. Do. A mail box 300 is provided on the further downstream side of the sheet post-processing apparatus Nitto 200 for discharging and sorting. This mail box 300 is an independent unit that can be arbitrarily and selectively attached to the paper post-processing apparatus 200.

  The transfer paper discharged from the image forming apparatus 100 passes through the inlet guide plate 201 of the paper post-processing device 200 and is carried into the paper post-processing device 200 by the transport roller 202. The sheet conveyance drive is performed by a step motor, and the sheet conveyance distance per pulse is known for control. Thereby, the paper can be accurately stopped at the punch punching position. In this embodiment, the gear ratio is set so that the conveyance distance can be controlled with a resolution of about 0.09 mm per pulse with a conveyance speed of 360 mm / s. In this embodiment, the conveyance is driven by driving an inlet driving unit that drives the inlet roller 202, a conveyance driving unit that drives the rollers 203, 212, and 213, a shift conveyance unit that drives the shift roller 222, and a discharge roller 223. It is divided into a paper discharge drive unit that discharges paper onto the paper tray 208, conveyance rollers 241, 242, and 243, and a lower conveyance drive unit that drives the tray discharge roller 244, and each drive unit can be driven independently. Reference numeral 231 denotes an open / close lever that opens and closes so that the paper discharge roller 223 does not interfere with the paper shift operation during the shift operation by the shift roller 222. The paper discharge roller 223 is rotatably provided on the free end side. It is rotatably supported by a support shaft on the end side.

  A press punch punching device 502 is arranged on the downstream side of the entrance roller 202, and the punching is performed by stopping the sheet conveyance at the punch punching position for each sheet. The upper conveyance path 210 and the conveyance path 220 are conveyance paths when the binding process is not performed on the paper. When the binding process is performed, the lower conveyance path 240 is conveyed and conveyed in the direction of the binding device (end-face stitching stapler) 401. .

  FIG. 2 is a block diagram showing the system configuration of the image forming apparatus 100, the sheet post-processing apparatus 200, and the mailbox 300. In the figure, the CPU 110 of the image forming apparatus 100 is connected to the CPU 291 of the sheet post-processing apparatus 200 via the interface 290 of the sheet post-processing apparatus 200. A ROM 292 storing a program is connected to the CPU 291, and the CPU 291 executes processing according to the program stored in the ROM 292 while using a RAM (not shown) as a work area. Detection information from a plurality of sensors 293 (not shown) of the sheet post-processing apparatus 200 is input to the CPU 292, and the CPU 291 instructs the CPU 350 of the mailbox 300 via the interface 351 based on the detection input.

  The mailbox 300 is controlled by the CPU 350. A ROM 353 storing a program is connected to the CPU 350, and the CPU 350 executes processing according to the program stored in the ROM 353 while using a RAM (not shown) as a work area. Further, the CPU 350 receives detection information from a plurality of sensors 352 provided in the mailbox 300 and detection information from each sensor 293 of the paper post-processing device 200, and receives instructions from the paper post-processing device 200. Based on the detection information from the sensors 293 and 352, the conveyance drive motor 370 and the solenoid 371 are controlled via the driver 360.

  FIG. 3 is a block diagram showing the system configuration of the image forming apparatus 100 and the sheet post-processing apparatus 200. As can be seen from the figure, the CPU 291 of the paper post-processing apparatus 200 is connected via a driver 294 to an inlet drive motor 2941, a transport drive motor 2942, a paper discharge drive motor 2944, a punch drive motor 2944, an electromagnetic clutch 2945, and others not described above. The motor 2945 and a plurality of solenoids 2947 are driven. Of these, the inlet drive motor 2941 drives the entrance roller 202, and the transport drive motor 2942 drives the transport drive unit and the lower transport drive unit (rollers 203, 212, 213, 241, 242, 243, 244) and discharges paper. The motor 2943 drives the paper discharge drive unit (paper discharge roller 223), and the punch drive motor drives the press punch device 502. Although not shown in FIG. 1, an electromagnetic clutch 2945, a solenoid 2947, and another motor 2946 provided in the apparatus are also driven by the CPU 291 through a driver 294.

  In the system according to the present embodiment configured as described above, when the mode for discharging to the mail box 300 is selected in the operation unit of the image forming apparatus 100, the sheet discharged from the image forming apparatus 100 is the back of the sheet. Through the inlet guide plate 201 of the processing apparatus 200. It is carried into the paper post-processing apparatus 200 by the conveyance roller 202. The paper passes through the branching claw 211 and the conveyance roller 212 and is conveyed to the conveyance path 310 to the mail box 300 by the branching claw 311, and any of the paper discharge trays 326 to 330 by the branching claws 304 to 307 and the paper discharge rollers 321 to 325. The paper is discharged to the tray and stacked.

  When punching is performed on the paper, and the paper is discharged onto the paper discharge trays 326 to 330 of the mail box 300 in synchronism with each other, as shown in the flowchart of FIG. The processing device 200 is activated, and each drive unit of the paper post-processing device 200 and the drive unit of the mail box 300 have a first transport speed (this embodiment) that is the same as the paper transport speed of the image forming apparatus 100 (hereinafter abbreviated as a main body). In this case, it is driven at 360 mm / s) to prepare for receiving paper. The sheet conveyance speed of the image forming apparatus main body 100 is transmitted to the sheet post-processing apparatus 200 along with the activation signal.

  At the same time as the leading edge of the sheet is discharged from the discharge roller 101 of the main body 100, a leading edge discharge signal (information that the leading edge of the sheet has passed the main body discharge roller) is transmitted from the main body 100 to the sheet post-processing device 200. At the same time, information on whether or not to perform paper size, punching, binding, etc. from the main body 100 and information on the paper discharge destination (paper discharge tray No. of the mail box 300) is also transmitted (step S101).

  The paper discharged from the main body 100 passes through the entrance guide plate 201 of the paper post-processing apparatus 200 and is carried into the paper post-processing apparatus 200 by the entrance conveyance roller 202 driven by the entrance driving unit. When the trailing edge of the sheet passes through the discharge roller 101 of the main body 100 (step S102), a trailing edge discharge signal (information that the trailing edge of the sheet has passed through the main body discharge roller 101) is simultaneously sent from the main body 100 to the sheet post-processing device 200. Sent. When the paper post-processing device 200 receives this information, the paper post-processing device 200 uses the entrance driving unit, the transport driving unit, the shift transport driving unit, and the paper discharge driving unit up to the second transport speed in order to gain punch processing time. Used for control such as increasing speed. The leading edge of the sheet is guided toward the conveyance path 310 described above.

  When the trailing edge of the sheet is detected by an inlet sensor 501 provided upstream in the conveyance direction of the inlet roller 202, the sheet post-processing device 200 counts the number of pulses sent to the conveyance driving motor, and the trailing edge of the sheet is the inlet roller. After passing 202, after an arbitrary number of pulses or time set in advance at an arbitrary timing (step S103), the sheet post-processing device 200 transmits a synchronous deceleration start timing signal to the mailbox 300, and enters the deceleration sheet punching position. Start deceleration operation to decelerate and stop. Mailbox 300 receives a deceleration start timing signal and simultaneously starts a deceleration operation for decelerating and stopping (step S104). The speed difference between the sheet post-processing apparatus 200 and the mailbox 300 is set to be the same as the acceleration after the deceleration stop of the sheet post-processing apparatus 200 and the mailbox 300, and the conveyance distance until the deceleration stop is controlled. This prevents paper loosening, breakage due to pulling, and jamming.

  Since the number of deceleration pulses or the deceleration time of each drive unit is set in advance, the sheet can be accurately stopped at the punch punching position. Since the sheet is decelerated and the sheet is stopped, the deviation of the stop position and the variation of the stop position can be reduced.

  When the paper stops (step S105), the clutch that transmits the driving force of the drive motor to the rotary shaft of the press punch processing device 502 is turned on, and punching by press punch is performed (step S106). During this time, the transport driving unit is stopped, but the entrance driving unit is driven at the first transport speed in order to completely discharge the preceding sheet because the entrance driving unit receives the subsequent sheet. When punching is completed (step S107), the sheet post-processing apparatus 200 transmits a synchronous acceleration start timing signal to the mailbox 300, and starts an acceleration operation up to the conveyance speed of the image forming apparatus 100 (step S108).

  The mail box 300 also receives the acceleration start timing signal and simultaneously starts the acceleration operation in synchronization with the post-processing device 200 up to the first conveyance speed that is the same as the conveyance speed of the image forming apparatus 100. Then, when the acceleration is completed (step S109) and the conveyance for the set number of pulses is completed (step S110), the sheet is discharged into the set mailbox (one of 326 to 330) (step S110). S111).

  As described above, the acceleration and acceleration transport distance until completion of acceleration of the sheet post-processing apparatus 200 and the mailbox 300 are set to be the same, and the sheet is controlled by the speed difference between the sheet post-processing apparatus 200 and the mailbox 300. Prevents loosening, pulling damage and jamming.

FIG. 5 is a flowchart showing a control procedure based on a conveyance synchronization signal from the paper post-processing apparatus 200 of the mailbox 300.
The mail box 300 performs the conveying operation as described above based on the acceleration or deceleration synchronization signal input from step S104 or step S108 of the sheet post-processing apparatus 200. In this control procedure, if the sheet is being conveyed (step S201), it is checked whether or not a deceleration timing signal has been received (step S202). When the deceleration timing signal is received, the conveyance drive motor 370 is decelerated. This deceleration timing signal is the deceleration timing signal transmitted from the sheet post-processing apparatus 200 in step S104 in FIG. When the vehicle is stopped or decelerated to the instructed speed (step S204), input of an acceleration timing signal is awaited. When the acceleration timing signal transmitted in step S108 is received from the paper post-processing apparatus 200 (step S205), the conveyance drive motor 370 is accelerated (step S206). When the acceleration is completed (step S207), the process returns to step S201. The cycle of checking whether the paper is being conveyed is repeated. As a result, the sheet can be conveyed while the acceleration / deceleration of the sheet post-processing apparatus 200 and the acceleration / deceleration of the mail box 300 are synchronized.

  Even when the acceleration / deceleration start timing signal is transmitted and received to synchronize the acceleration / deceleration in this way, the transmission side generally transmits the signal until the receiving side starts the acceleration / deceleration speed operation, depending on the processing time of each control unit. A delay of about several ms will occur. Therefore, when the delay time is known in advance, the transmission side of the acceleration / deceleration start timing signal can advance the transmission timing by this delay time, thereby improving the timing matching accuracy of acceleration / deceleration synchronous control.

  In another embodiment, a circuit that can detect the detection signal of the entrance sensor 501 of the paper post-processing device 200 also on the side of the mail box 300 is provided, so that the position of the paper transported by the post-processing device 200 can be set in the mail box 300. The timing can be synchronized with the acceleration / deceleration start position of the sheet post-processing apparatus 200 by the number of transport pulses of the drive unit in the same manner as that performed by the sheet post-processing apparatus 200. In this method, it is possible to eliminate the deviation of the start timing of the acceleration speed due to the response time of the transmission / reception, and it is possible to increase the timing matching accuracy of the synchronous control.

  When changing the punch punching position, the mailpox 300 synchronizes the control pulse for the speed of acceleration and the stop position with the sheet post-processing apparatus 200 according to the mode information from the image forming apparatus 100.

FIG. 6 is a flowchart showing a control procedure when the conveyance synchronization control is performed based on the detection signal of the entrance sensor 501 of the paper post-processing apparatus 200 of the mail box 300.
In this control procedure, punch processing is performed (step S301), and if the paper size needs to be synchronized (step S302), the paper trailing edge is detected by the entrance sensor 501 of the paper post-processing device 200 (step S303). When the number of pulses set in advance to stop the sheet is conveyed (step S304), the conveyance drive motor 370 is decelerated (step S305), and the sheet is stopped at the punching position (step S306). Waiting for the punching operation time while stopped at the punching position (step S307), when punching is completed (step S308), the conveyance drive motor 370 is started to accelerate (step S309), and when a predetermined speed is reached, the acceleration is accelerated. Stopped and transported at a constant speed (step S310). Then, the punched paper is transported to the transport roller 301 of the mail box 300 at a first transport speed that is the same as the paper transport speed of the main body 100, and any one of the discharge rollers 321 to 325 according to the discharge destination information of the main body 100. Then, the paper is discharged to one of the paper discharge trays 326 to 330. On the other hand, the synchronization control is not performed if the paper has a short size in the transport direction that does not need to be synchronized in step S302.

  In the case of a mechanism in which punch punching is performed by temporarily stopping the paper in this way, the productivity between the punched paper and the subsequent paper continuously conveyed from the image forming apparatus 100 is clogged. There is a long way to go down. If the size in the paper transport direction is short and the post-processing device 200 has a size that does not reach the entrance transport roller 301 of the mail box 300 when the post-processing device 200 completes acceleration up to the first transport speed after punching, the mail pox 300 is used. Since there is no need to synchronize with the paper post-processing apparatus 200, in such a case, the mail box 300 can be controlled so as not to stop synchronization when punching the paper post-processing apparatus 200, thereby preventing a decrease in productivity. .

  As described above, according to the present embodiment, the following effects can be obtained.

(1) When the conveyance speed between the paper post-processing apparatus 200 and the mailbox 300 is different, the conveyance speed is changed in synchronism with the change timing of the acceleration / deceleration and start / stop conveyance speed between the two. The paper can be smoothly conveyed without causing paper slack, pulling, paper breakage, jamming, and the like.

(2) Since the sheet is conveyed in synchronism only when the sheet size is long in the conveying direction so as to straddle the conveying drive mechanism on both sides of the sheet post-processing apparatus 200 and the mail box 300, it is possible to straddle both sides. It is possible to prevent a decrease in productivity of small-size paper.

(3) Since the sheet is conveyed with the same acceleration / deceleration between the sheet post-processing apparatus 200 and the mailbox 300, the acceleration / deceleration at the time of starting / stopping, and the acceleration / deceleration distance, the sheet is slackened and pulled due to the speed difference between the two. Can be smoothly conveyed without causing breakage, jamming, or the like.

(4) When changing the conveyance speed, the conveyance speed is changed based on the timing signal transmitted and received between the two units, and the timing to synchronize is set. In addition, the paper can be smoothly transported without causing paper breakage or jamming.

(5) Since the transmission side of the conveyance speed change timing signal shifts the signal transmission delay time and transmits the timing signal, the sheet is slackened due to the speed difference between them, and the sheet is damaged or jammed. It can be transported smoothly without any problems.

(6) The sheet post-processing apparatus 200 on the upstream side in the sheet conveyance direction includes an inlet sensor 501 that detects the conveyance of the sheet, and the mail box 300 on the downstream side of the sheet conveyance is based on the detection signal from the inlet sensor 501, Since the change timing is determined and the sheet is conveyed in synchronism with the sheet post-processing apparatus 200, the sheet can be smoothly conveyed without causing the sheet to be slack due to the difference in speed between the two, the breakage of the sheet, jamming, or the like. .

(7) Since the conveyance speed is changed according to the sheet processing mode, it can be controlled according to the processing mode. Even if the mode is changed, the sheet is not slackened or pulled due to the speed difference between the two. It can be transported smoothly without causing damage or jamming.

1 is a diagram illustrating a schematic configuration of a system including an image forming apparatus, a sheet post-processing apparatus, and a mail box according to a backing embodiment of the present invention. It is a block diagram which shows the electric constitution of the system of FIG. 1 is a block diagram illustrating a system configuration of an image forming apparatus and a sheet post-processing apparatus. 6 is a flowchart illustrating a control procedure of conveyance synchronization control of the sheet post-processing apparatus. It is a flowchart which shows the control procedure by the conveyance synchronizing signal of a mailbox. It is a flowchart which shows the control procedure by the post-processing sensor detection signal of a mailbox.

Explanation of symbols

100 Image forming apparatus body 110 CPU
200 Paper post-processing device 291 CPU
294 Driver 2942 Transport drive motor 300 Mail box 304 to 307 Branch claw 310 Transport path 311 Branch claw 321 to 325 Paper discharge roller 326 to 330 Paper discharge tray 350 CPU
360 Driver 370 Carrying drive motor 501 Entrance sensor

Claims (13)

  When conveying the sheet-like recording medium from the first apparatus to the second apparatus, the conveyance speed change timings are synchronized when the conveyance speeds of the first and second apparatuses are different. Synchronous transport method.   2. The synchronous conveyance method according to claim 1, wherein the first apparatus is a sheet processing apparatus that performs a predetermined process on the sheet-like recording medium into which the first apparatus is carried.   3. The synchronous conveyance method according to claim 2, wherein the second apparatus is a mail box for sorting sheets discharged from the sheet processing apparatus. In a sheet conveying apparatus that conveys a sheet between a plurality of units,
A sheet conveying apparatus comprising: means for conveying a sheet-like recording medium in synchronization with a change timing of each conveying speed when the conveying speeds of the two units delivering the sheets are different.   5. The sheet conveying apparatus according to claim 4, wherein the change timing of the conveyance speed includes one of acceleration / deceleration timing and start / stop timing.   6. The sheet conveying apparatus according to claim 4, wherein when the sheet straddles the conveyance driving system of the two units, the conveying unit synchronizes timings of changing the conveying speeds. 6.   The sheet according to any one of claims 4 to 6, wherein the conveying unit conveys the acceleration / deceleration between the two units, the acceleration / deceleration at the time of starting and stopping, and the acceleration / deceleration distance as equal. Conveying device.   8. The conveyance means sets the timing for changing and synchronizing the conveyance speed based on a timing signal transmitted and received between the two units when changing the conveyance speed. The sheet conveying apparatus according to any one of the above.   9. The sheet conveying apparatus according to claim 8, wherein a transmission side of the conveyance speed change timing signal transmits the timing signal while shifting a signal transmission delay time.   The upstream unit in the sheet conveyance direction of the two units includes a detection unit that detects the conveyance of the sheet, and the unit on the downstream side of the sheet conveyance determines the conveyance speed change timing based on a detection signal from the detection unit, The sheet conveying apparatus according to any one of claims 4 to 9, wherein the sheet conveying apparatus conveys in synchronization with the upstream unit.   The sheet conveying apparatus according to claim 4, wherein the conveying unit changes the conveying speed according to a sheet processing mode.   One of the units is a sheet processing apparatus that performs a predetermined process on the sheet-like recording medium and discharges the sheet, and the other is a mail box provided on the downstream side in the sheet conveying direction of the sheet processing apparatus. The sheet conveying apparatus according to any one of claims 4 to 11. An image forming apparatus for forming an image on the sheet;
The sheet conveying apparatus according to any one of claims 4 to 12, which conveys a sheet discharged from the image forming apparatus,
An image forming system comprising:

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