JP2016118743A - Image formation system, image formation device, sheet transportation method and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide reliable sheet transportation with a simple control, with no special configuration provided.SOLUTION: An image formation system is provided with an image formation device 10 which forms an image on a sheet, and a first sheet processing device 20 which is connected to a lower stream side of the image formation device 10 along sheet transportation direction. The first sheet processing device 20 includes an in-line sensor 23 which reads an image of the sheet that is transported from the image formation device 10, and a circulation path 26 for transporting the sheet that has passed through the in-line sensor 23 to the in-line sensor 23 again. The image formation device 10 estimates position of preceding sheets P-Pbeing transported in the first sheet processing device 20, and based on the estimation result, controls a sending timing of the sheet Pto the first sheet processing device 20 while avoiding the sheet Pfrom colliding with the preceding sheets P-P.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an image forming system, an image forming apparatus, a sheet conveying method, and a program.

  2. Description of the Related Art Conventionally, an image forming system in which an image forming apparatus such as a copying machine or a printer and a paper processing apparatus that performs paper processing such as binding processing and sorting processing on paper on which an image is formed by the image forming apparatus has been used. It has been. In the image forming system, a technique is known in which the image forming apparatus side secures a sheet interval from a preceding sheet required in the sheet processing apparatus and sends the sheet to the sheet processing apparatus.

  For example, in an image forming apparatus in which post-processing devices having a plurality of post-processing functions are connected, when the post-processing function is switched, for each combination of the post-processing function before the change and the post-processing function after the change There has been proposed an image forming apparatus that controls the sheet interval between the last sheet before changing the post-processing function and the first sheet after changing based on a preset switching time (see Patent Document 1).

  Even if paper transport to the paper processing apparatus may be delayed due to the cause of the image forming apparatus such as paper feed tray switching or image quality adjustment in the image forming apparatus, the paper normally required in the paper processing apparatus If an interval equal to or greater than the interval can be secured, a jam does not occur due to a paper collision or the like.

JP 2005-323059 A

  However, in a paper processing apparatus that circulates paper in order to process each side of the paper, the same paper passes through the same location in the transport path more than once in the paper processing apparatus. When the conveyance of the sheet is delayed due to the cause, there is a possibility that the preceding sheet circulating in the sheet processing apparatus collides with the sheet conveyed with a delay from the image forming apparatus and a jam occurs.

  In order to avoid this, a buffer for waiting paper is provided between the image forming apparatus and the paper processing apparatus, or information on the conveyance state is communicated between the image forming apparatus and the paper processing apparatus. However, methods for controlling the conveyance of the paper are also conceivable. However, since the configuration and control of the apparatus are complicated, there is a problem that the cost is increased and the reliability is lowered.

  An object of the present invention is to provide a highly reliable paper transport with simple control without providing a special configuration.

  In order to solve the above problem, an invention according to claim 1 is an image forming system comprising: an image forming apparatus; and a sheet processing apparatus connected to a downstream side of the image forming apparatus in a sheet conveying direction. The sheet processing apparatus includes a sheet processing unit that performs predetermined sheet processing on the sheet conveyed from the image forming apparatus, and a circulation path for conveying the sheet that has passed through the sheet processing unit to the sheet processing unit again. The image forming apparatus estimates an image forming unit that forms an image on a sheet and a position of the sheet being conveyed in the sheet processing apparatus, and the image is formed based on the estimation result. A control unit that controls a timing at which the image-formed sheet is sent to the sheet processing apparatus so that the sheet does not collide with the sheet being conveyed in the sheet processing apparatus.

  According to a second aspect of the present invention, in the image forming system according to the first aspect, the control unit is configured such that the sheet conveyance speed in the sheet processing apparatus and the sheet conveyed in the sheet processing apparatus are the sheet. Based on the timing sent to the processing device, the size of the paper transported in the paper processing device, and the length of the circulation path, the position of the paper transported in the paper processing device is estimated.

  According to a third aspect of the present invention, in the image forming system according to the first or second aspect, the controller is configured to determine the position of one or more sheets in the estimated sheet processing apparatus, and Timing of sending the image-formed paper to the paper processing device based on the size of the paper sent to the paper processing device, the minimum paper interval required in the paper processing device, and a margin due to an estimation error To control.

  According to a fourth aspect of the present invention, in the image forming system according to any one of the first to third aspects, the control unit includes a plurality of sheets conveyed through the sheet processing apparatus. The timing of feeding the image-formed paper to the paper processing apparatus is controlled so that the image-formed paper is inserted.

  The invention according to claim 5 is the image forming system according to any one of claims 1 to 4, wherein the sheet processing unit reads images formed on both sides of the sheet one by one, The sheet processing apparatus includes an evaluation unit that evaluates image quality based on the read image.

  According to a sixth aspect of the present invention, there is provided a sheet processing apparatus comprising: a sheet processing unit that performs predetermined sheet processing on a sheet; and a circulation path for transporting the sheet that has passed through the sheet processing unit to the sheet processing unit again. In contrast, the image forming apparatus is connected to the upstream side in the sheet conveyance direction, and the position of the image forming unit that forms an image on the sheet and the sheet conveyed in the sheet processing apparatus is estimated, and the estimation is performed. Based on the result, a control unit that controls the timing of sending the image-formed paper to the paper processing device so that the paper on which the image is formed does not collide with the paper being conveyed in the paper processing device; Is provided.

  According to a seventh aspect of the present invention, there is provided a paper processing apparatus comprising: a paper processing unit that performs predetermined paper processing on a paper; and a circulation path for transporting the paper that has passed through the paper processing unit to the paper processing unit again. In contrast, a paper transport method in an image forming apparatus that is connected to the upstream side in the paper transport direction and forms an image on a paper, the step of estimating the position of the paper transported in the paper processing apparatus, Controlling the timing of sending the image-formed paper to the paper processing device so that the image-formed paper does not collide with the paper being conveyed in the paper processing device based on the estimation result; including.

  The invention according to claim 8 includes a sheet processing unit that performs predetermined sheet processing on the sheet, and a circulation path for transporting the sheet that has passed through the sheet processing unit to the sheet processing unit again. On the other hand, the computer of the image forming apparatus that is connected upstream in the paper transport direction and forms an image on the paper, estimates the position of the paper being transported in the paper processing apparatus, and based on the estimation result, A program for functioning as a control unit for controlling the timing of sending the image-formed paper to the paper processing apparatus so that the image-formed paper does not collide with the paper conveyed in the paper processing apparatus. is there.

  According to the present invention, it is possible to provide highly reliable paper conveyance with simple control without providing a special configuration.

1 is an overall configuration diagram of an image forming system in an embodiment of the present invention. 1 is a block diagram illustrating a functional configuration of an image forming system. 6 is a flowchart illustrating a paper conveyance timing control process executed in the image forming apparatus. FIG. 4 is a diagram illustrating an example of arrangement of preceding sheets when a sheet is conveyed from the image forming apparatus to a first sheet processing apparatus. It is a figure which shows the state which expand | deployed the circulation path along the conveyance path | route in a 1st paper processing apparatus. It is a figure which shows the sheet | seat space | interval required in order to send out in the form which inserts a sheet | seat between the preceding sheets circulating in the 1st sheet processing apparatus.

  Embodiments of an image forming system according to the present invention will be described below. The present invention is not limited to the illustrated example.

FIG. 1 is an overall configuration diagram of an image forming system 100 according to the present embodiment.
As shown in FIG. 1, the image forming system 100 includes an image forming apparatus 10, a first sheet processing apparatus 20, and a second sheet processing apparatus 30 that are connected in series along the sheet conveying direction. In the image forming system 100, predetermined paper processing is performed on the paper on which the image is formed by the image forming apparatus 10 in the first paper processing apparatus 20 and the second paper processing apparatus 30.

  The image forming apparatus 10 is connected to the upstream side of the first sheet processing apparatus 20 in the sheet conveyance direction, forms an image on the sheet, and sends the image-formed sheet to the first sheet processing apparatus 20. The image forming apparatus 10 includes an image reading unit 13, an image forming unit 14, an operation unit 15, a display unit 16, a circulation path 19, and the like.

The image reading unit 13 includes an ADF (automatic document feeder), a scanner, and the like, and outputs image data obtained by reading an image of the document to the control unit 12 (see FIG. 2).
The image forming unit 14 forms an image on a sheet based on the image data read by the image reading unit 13 or image data received from an external device. Specifically, the image forming unit 14 includes four sets of an exposure unit, a development unit, and a photoreceptor for each of yellow, magenta, cyan, and black colors. The exposure unit exposes the charged photoreceptor by optical scanning based on the image data. The developing unit develops the electrostatic latent image formed on the photoreceptor by exposure with toner. The images of the respective colors formed on the photoconductors corresponding to the respective colors in this manner are transferred and superimposed on a sheet via an intermediate transfer belt or the like, and are subjected to a fixing process by a fixing device.

The operation unit 15 includes a touch panel formed so as to cover the display screen of the display unit 16 and various operation buttons such as numeric buttons and a start button, and outputs operation signals based on user operations to the control unit 12.
The display unit 16 is configured by an LCD (Liquid Crystal Display), and displays various screens according to instructions of display signals input from the control unit 12.

  The circulation path 19 is a transport path for transporting the paper that has passed through the image forming unit 14 to the image forming unit 14 again. The circulation path 19 includes a reversing mechanism 19A for reversing the paper surface, so that the image forming unit 14 can form images on both surfaces of the paper.

The first sheet processing apparatus 20 is connected to the downstream side of the image forming apparatus 10 in the sheet conveying direction, performs predetermined sheet processing on the sheet conveyed from the image forming apparatus 10, and outputs the sheet after the sheet processing to the second sheet. The paper is sent to the paper processing device 30.
The first paper processing device 20 includes an inline sensor 23 as a paper processing unit that performs predetermined paper processing on the paper conveyed from the image forming device 10, and the image of the paper image formed by the image forming device 10 is inline sensor 23, and the image quality is evaluated. Examples of the image quality to be evaluated include density, color shift, image order, and paper breakage.

  The in-line sensor 23 has a plurality of light receiving elements arranged at predetermined intervals in a direction orthogonal to the paper transport direction, reads an image on the transported paper, and outputs the obtained image data to the control unit 22 (see FIG. 2). ). Each light receiving element outputs a signal corresponding to the intensity of light emitted from the light source and reflected from the surface of the paper. As the inline sensor 23, for example, a CCD (Charge Coupled Device) sensor or a CMOS (Complementary Metal Oxide Semiconductor) sensor is used.

Further, the first paper processing apparatus 20 includes a circulation path 26 for transporting the paper that has passed through the inline sensor 23 to the inline sensor 23 again.
The circulation path 26 includes a reversing mechanism 26A for reversing the paper surface, and the first paper processing device 20 can read the images formed on both surfaces of the paper one by one and evaluate the image quality. ing.

The second paper processing device 30 is connected to the downstream side of the first paper processing device 20 in the paper transport direction, performs predetermined paper processing on the paper transported from the first paper processing device 20, and performs post-paper processing. Eject the paper out of the machine. The second sheet processing apparatus 30 includes a saddle stitching unit 33, a cutting unit 34, and the like.
The saddle stitching unit 33 performs saddle stitching processing on the bundle of sheets received from the first sheet processing apparatus 20.
The cutting unit 34 cuts the top and bottom of the sheet bundle after the saddle stitching process.

FIG. 2 is a block diagram illustrating a functional configuration of the image forming system 100.
The image forming apparatus 10 includes an I / F (InterFace) unit 11, a control unit 12, an image reading unit 13, an image forming unit 14, an operation unit 15, a display unit 16, a transport unit 17, a storage unit 18, and the like. Note that description of the functional units already described is omitted.

  The I / F unit 11 transmits and receives data to and from the first sheet processing apparatus 20. The I / F unit 11 transmits and receives data to and from an external device connected to a communication network such as a LAN (Local Area Network).

  The control unit 12 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The CPU reads various processing programs stored in the ROM, expands them in the RAM, and centrally controls the operations of the respective units of the image forming apparatus 10 according to the expanded programs.

  The control unit 12 estimates the position of the sheet being conveyed in the first sheet processing apparatus 20. Specifically, the control unit 12 sends the sheet conveyance speed in the first sheet processing apparatus 20 and the sheet conveyed in the first sheet processing apparatus 20 from the image forming apparatus 10 to the first sheet processing apparatus 20. The first sheet processing apparatus based on the timing of the sheet, the size of the sheet conveyed in the first sheet processing apparatus 20 (length in the sheet conveying direction), and the length of the circulation path 26 in the first sheet processing apparatus 20. The position of the sheet being conveyed in 20 is estimated.

The control unit 12 does not collide the sheet on which the image is formed with the sheet conveyed in the first sheet processing apparatus 20 based on the estimation result about the position of the sheet conveyed in the first sheet processing apparatus 20. In this manner, the timing at which the image-formed paper is sent to the first paper processing device 20 is controlled. Specifically, the controller 12 estimates the position of one or more sheets in the first sheet processing apparatus 20 and the size of the sheet to be sent next to the first sheet processing apparatus 20 (sheet conveyance direction). The timing at which the image-formed paper is sent to the first paper processing device 20 is controlled based on the minimum paper interval required in the first paper processing device 20 and the margin due to the estimation error. .
For example, the control unit 12 transfers the image-formed sheet to the first sheet processing apparatus so that the image-formed sheet is inserted between the plurality of sheets conveyed in the first sheet processing apparatus 20. The timing to send to 20 is controlled.

The transport unit 17 includes a transport roller for transporting the paper, and transports the paper in the image forming apparatus 10.
The storage unit 18 is configured by a hard disk, a flash memory, or the like, and stores various data. The storage unit 18 stores the conveyance speed of the sheet in the first sheet processing apparatus 20, the length of the circulation path 26 in the first sheet processing apparatus 20 (hereinafter referred to as the circulation path path length), and the first sheet processing apparatus 20. Due to the length from the entrance to the entrance of the circulation path 26 (hereinafter referred to as the pre-entrance path length), the minimum required sheet interval in the first sheet processing apparatus 20 (hereinafter referred to as the minimum sheet interval), and the estimation error. Margin is stored. Further, in the storage unit 18, for each sheet sent from the image forming apparatus 10 to the first sheet processing apparatus 20, the timing at which the sheet is sent to the first sheet processing apparatus 20 and the size of the sheet are stored. Correspondingly stored.

  The first sheet processing apparatus 20 includes an I / F unit 21, a control unit 22, an inline sensor 23, a transport unit 24, a storage unit 25, and the like. Note that description of the functional units already described is omitted.

  The I / F unit 21 transmits / receives data to / from the image forming apparatus 10 and the second sheet processing apparatus 30.

  The control unit 22 includes a CPU, a ROM, a RAM, and the like. The CPU reads out various processing programs stored in the ROM, expands them in the RAM, and centrally controls the operation of each unit of the first sheet processing apparatus 20 according to the expanded programs.

  The control unit 22 controls the conveyance unit 24 to circulate and convey the paper in the first paper processing device 20 regardless of the interval of the paper sent out from the image forming apparatus 10. The sheet is conveyed so that one side of the sheet faces the inline sensor 23, passes through the position of the inline sensor 23, and then reversed by the reversing mechanism 26 </ b> A while being conveyed through the circulation path 26. The position of the inline sensor 23 is returned again so as to face the inline sensor 23. The paper after both sides of the paper are read by the inline sensor 23 is sent to the second paper processing device 30.

  The control unit 22 evaluates the image quality for each of the front and back surfaces of the paper based on the image data obtained by reading the images formed on the front and back surfaces of the paper one by one with the inline sensor 23. That is, the control unit 22 functions as an evaluation unit. For example, the control unit 22 determines whether the density is within a predetermined range, whether there is no color misregistration, whether the image formed on the paper is in the intended order, or whether paper breakage has occurred. Evaluate etc. The control unit 22 stores the image quality evaluation result data in the storage unit 25 and transmits the data to the image forming apparatus 10 via the I / F unit 21.

The transport unit 24 includes a transport roller for transporting the paper, and transports the paper in the first paper processing apparatus 20.
The storage unit 25 is configured by a hard disk, a flash memory, or the like, and stores various data.

  The second sheet processing apparatus 30 includes an I / F unit 31, a control unit 32, a saddle stitching unit 33, a cutting unit 34, a transport unit 35, a storage unit 36, and the like. Note that description of the functional units already described is omitted.

  The I / F unit 31 transmits and receives data to and from the first sheet processing apparatus 20.

  The control unit 32 includes a CPU, a ROM, a RAM, and the like. The CPU reads various processing programs stored in the ROM, expands them in the RAM, and centrally controls the operations of the respective units of the second sheet processing apparatus 30 according to the expanded programs.

The transport unit 35 includes a transport roller for transporting the paper, and transports the paper in the second paper processing apparatus 30.
The storage unit 36 is configured by a hard disk, a flash memory, or the like, and stores various data.

Next, the operation in the image forming apparatus 10 will be described.
FIG. 3 is a flowchart showing a paper conveyance timing control process executed in the image forming apparatus 10. This process is realized by software processing in cooperation with the CPU of the control unit 12 and the program stored in the ROM.

  First, the control unit 12 controls the transport unit 17 and the image forming unit 14 when there is an image formation instruction based on the image data read by the image reading unit 13 or image data received from an external device. Then, image formation is started (step S1).

  Next, the control unit 12 determines whether preparation for transporting the sheet to the first sheet processing apparatus 20 is completed (step S2). Specifically, the control unit 12 eliminates all the factors that cause the paper delivery to be delayed due to the convenience of the image forming apparatus 10, or finishes image formation on the paper, and always supplies the paper to the first paper processing apparatus 20. Judge whether it is ready to send out.

When the preparation for conveying the sheet to the first sheet processing apparatus 20 is completed (step S2; YES), the control unit 12 starts the sheet that has been prepared for conveyance to the first sheet processing apparatus 20 in step S1. It is determined whether or not it is the first sheet in the formed image (step S3).
When the sheet ready for conveyance to the first sheet processing apparatus 20 is the first sheet (step S3; YES), the control unit 12 controls the conveyance unit 17 to control the first sheet processing apparatus. The conveyance of the sheet to 20 is started (step S4).

  In step S3, when the sheet ready for conveyance to the first sheet processing apparatus 20 is not the first sheet (step S3; NO), that is, there is a preceding sheet that has already been conveyed to the first sheet processing apparatus 20. If so, the control unit 12 estimates the position of the preceding sheet being conveyed in the first sheet processing apparatus 20 (step S5).

4 shows an example of the arrangement of the preceding sheet _P N-3 _{to P N-1} at the time of conveying the paper _{P N} from the image forming apparatus 10 to the first sheet processing apparatus 20. In FIG. 4, the description of the reversing mechanism 19A of the image forming apparatus 10 and the reversing mechanism 26A of the first paper processing apparatus 20 is omitted, but the paper actually being transported in the first paper processing apparatus 20 is omitted. When estimating the position, the transport path in the reversing mechanism 26A is also taken into consideration.
FIG. 5 shows a state in which the circulation path 26 is developed along the paper transport path in the first paper processing apparatus 20.

The control unit 12 estimates the positions of the preceding sheets P _{N-3 to} P _N−1 conveyed in the first sheet processing apparatus 20 in the first sheet processing apparatus 20. Specifically, the control unit 12 sends the preceding sheets P _{N-3 to} P _N-1 from the image forming apparatus 10 to the first sheet processing apparatus 20, the sheet conveyance speed in the first sheet processing apparatus 20. Timing, size L _{N-3 to} L _{N-1 of} preceding sheets P _{N-3 to} P _N-1 , path length before entrance L _S (length between A and B shown in FIG. 4), circulation path path length L _P (the length between B-C-D-E-B shown in FIG. 4) is read from the storage unit 18, and the positions of the preceding sheets P _{N-3 to} P _N-1 are estimated based on these pieces of information. .

For example, the control unit 12 sends the first paper processing device 20 to the first paper processing device 20 based on the timing at which the preceding paper _PN-3 is sent to the first paper processing device 20 and the paper conveyance speed (A shown in FIG. 4). To the leading edge of the preceding paper _PN-3 , the length along the transport path is calculated. Based on the length from the position A to the leading edge of the preceding sheet P _{N-3 and} the size L _N-3 of the preceding sheet P _N-3 , the control unit 12 sets the position from the position A to the trailing edge of the preceding sheet P _N-3 . Calculate the length along the transport path. The control unit 12 determines the length from the position A to the leading edge of the preceding sheet P _N-3 , the length from the position A to the trailing end of the preceding sheet P _N-3 , the pre-entry path length L _S , and the circulation path path length L. _{From P} , the position of the preceding paper _PN-3 is estimated. Note that if the pre-entrance route length L _S is substantially zero, it is not necessary to consider the pre-entrance route length L _S.
The same applies to the preceding paper _PN-2 and the preceding paper _PN-1 .

  Here, the case where the position for controlling the timing of feeding the sheet from the image forming apparatus 10 to the first sheet processing apparatus 20 (the position where the sheet to be fed is stopped) is the position A shown in FIG. 4 has been described as an example. In the case where a position for controlling the timing of feeding the sheet from the image forming apparatus 10 to the first sheet processing apparatus 20 exists in the image forming apparatus 10, the length from the position to the first sheet processing apparatus 20 is also entered. Consider.

  In addition, since the sheet cannot be inserted downstream from the position where the sheet conveyed through the circulation path 26 again joins the inlet of the circulation path 26 (the position where the sheet passes B for the second time in FIG. 5), the preceding sheet cannot be inserted. When estimating the position of the sheet, the sheet downstream from the merging position does not have to be an estimation target.

  Next, based on the estimated position of the preceding sheet in the first sheet processing apparatus 20, the control unit 12 sets the first sheet processing apparatus between the preceding sheets conveyed in the first sheet processing apparatus 20. It is determined whether or not the next sheet sent to 20 can be inserted (step S6).

  If the next sheet can be inserted between the preceding sheets conveyed in the first sheet processing apparatus 20 (step S6; YES), the control unit 12 controls the conveying unit 17 to control the preceding sheet. At the timing when the sheet can be inserted, the next sheet is started to be conveyed to the first sheet processing apparatus 20 (step S7). Here, when there are a plurality of insertable preceding sheets, the sheet is inserted between the sheets sent from the image forming apparatus 10 to the first sheet processing apparatus 20 earlier.

  On the other hand, when it is not possible to insert the next sheet between the preceding sheets conveyed in the first sheet processing apparatus 20 in step S6 (step S6; NO), the control unit 12 controls the conveyance unit 17. Then, at the timing after the trailing edge of the last preceding sheet, the next sheet is started to be conveyed to the first sheet processing apparatus 20 (step S8).

In FIG. 6, the sheet interval (necessary for sending the sheet _PN to the first sheet processing apparatus 20 in the form of being inserted between a plurality of preceding sheets circulating in the first sheet processing apparatus 20. Hereinafter, it is referred to as an insertion sheet interval). Then the size of the paper P _N fed from the image forming apparatus 10 to the first sheet processing apparatus 20 L _N, the minimum sheet spacing in the first sheet processing apparatus 20 K, a margin due to estimation error is M, the insertion sheet interval X is represented by the following formula.
Insert paper interval X = paper size L _N + minimum paper interval K × 2 + margin M × 2

For example, as illustrated in FIG. 5, the control unit 12 determines the sheet interval between the preceding sheet P _N-3 and the preceding sheet P _N-2 based on the estimated positions of the preceding sheets P _{N-3 to} P _N−1. Y, the paper interval Z between the preceding paper P _N-2 and the preceding paper P _N-1 is calculated. Then, the control unit 12 compares the sheet interval Y and the sheet interval Z with the inserted sheet interval X.

(1) When Inserted Paper Interval X ≦ Paper Interval Y The control unit 12 controls the first paper processing device 20 so that the paper _PN is inserted between the preceding paper _PN-3 and the preceding paper _PN-2. paper P _N at a timing which fit into sheet interval Y in the inlet of the circulation path 26 (position B shown in FIG. 4), to convey the sheet P _N from the image forming apparatus 10 to the first sheet processing apparatus 20.
Here, the control unit 12 adds the minimum sheet interval K and the margin M between the preceding sheet _PN-3 and the sheet _PN , and between the sheet _PN and the preceding sheet _PN-2 , respectively. The timing of feeding the paper _PN to the first paper processing device 20 is controlled so that the interval is secured.

When determining whether or not the sheet _PN can be inserted into the sheet interval Y, the path length L _S before entrance (more precisely, the sheet is fed from the image forming apparatus 10 to the first sheet processing apparatus 20. The length from the position for controlling the delivery timing to the inlet of the circulation path 26) is taken into consideration. If the pre-entrance route length L _S is substantially 0, it is not necessary to consider the pre-entry route length L _S.

(2) When Paper Interval Y <Inserted Paper Interval X ≦ Paper Interval Z The control unit 12 sets the _{first PN} so that the paper _PN is inserted between the preceding paper _PN-2 and the preceding paper _PN- 1. The sheet _PN is transported from the image forming apparatus 10 to the first sheet processing apparatus 20 at a timing when the sheet _PN is within the sheet interval Z at the entrance of the circulation path 26 of the sheet processing apparatus 20 (position B shown in FIG. 4). .
Here, the control unit 12 adds the minimum sheet interval K and the margin M between the preceding sheet _PN-2 and the sheet _PN , and between the sheet _PN and the preceding sheet _PN-1 , respectively. The timing of feeding the paper _PN to the first paper processing device 20 is controlled so that the interval is secured.

When determining whether or not the sheet _PN can be inserted into the sheet interval Z, the path length before entrance L _S (more precisely, the sheet is fed from the image forming apparatus 10 to the first sheet processing apparatus 20. The length from the position for controlling the delivery timing to the inlet of the circulation path 26) is taken into consideration. If the pre-entrance route length L _S is substantially 0, it is not necessary to consider the pre-entry route length L _S.

(3) In the case where the sheet interval Z <the insertion sheet interval X, the control unit 12 performs image processing at a timing at which a minimum interval equal to the minimum sheet interval K and the margin M is secured from the last preceding sheet _PN-1. The sheet _PN is conveyed from the forming apparatus 10 to the first sheet processing apparatus 20. That is, the control unit 12, after all of the preceding sheet _{P N-3, P N-} 2, P N-1 has passed the entrance of the circulation path 26 (position B shown in FIG. 4) again, the paper _{P N} is Subsequently, the paper _PN is sent out so as to be conveyed.

  After step S4, step S7 or step S8, the control unit 12 causes the storage unit 18 to store the timing at which the sheet is sent to the first sheet processing apparatus 20 and the sheet size in association with each other (step S9).

  Next, the control unit 12 determines whether there is a next sheet to be sent to the first sheet processing apparatus 20 (step S10). If there is a next sheet (step S10; YES), the process returns to step S2 and the process is repeated.

If there is no next sheet in step S10 (step S10; NO), the control unit 12 ends the image formation (step S11).
Thus, the paper conveyance timing control process is completed.

  As described above, according to the present embodiment, the position of the sheet being conveyed in the first sheet processing apparatus 20 is estimated on the image forming apparatus 10 side, and an image is formed based on the estimation result. Since the timing at which the image-formed paper is sent to the first paper processing device 20 is controlled so that the paper does not collide with the paper conveyed in the first paper processing device 20, a special configuration such as a buffer is provided. In addition, it is possible to provide highly reliable paper conveyance with simple control.

  In addition, the conveyance speed of the sheet in the first sheet processing apparatus 20, the timing at which the sheet conveyed in the first sheet processing apparatus 20 is sent from the image forming apparatus 10 to the first sheet processing apparatus 20, the first sheet processing Since the position of the sheet being conveyed in the first sheet processing apparatus 20 is estimated based on the size of the sheet being conveyed in the apparatus 20 and the circulation path path length in the first sheet processing apparatus 20, The position can be estimated with high accuracy.

Further, the estimated position of the sheet in the first sheet processing apparatus 20, the size of the sheet sent to the first sheet processing apparatus 20, the minimum sheet interval in the first sheet processing apparatus 20, and the margin due to the estimation error Based on the above, it can be determined whether or not the next sheet to be sent out can be inserted between the sheets conveyed in the first sheet processing apparatus 20.
When the next sheet can be inserted between the sheets conveyed in the first sheet processing apparatus 20, the next sheet is inserted between the sheets in the first sheet processing apparatus 20. The timing for sending the next sheet to the first sheet processing apparatus 20 is controlled.
On the other hand, when the next sheet cannot be inserted between the sheets being conveyed in the first sheet processing apparatus 20, the next sheet is transferred to the first sheet so that the next sheet is conveyed after the last preceding sheet. The timing to send to the paper processing apparatus 20 is controlled.

  The description in the above embodiment is an example of the image forming system according to the present invention, and the present invention is not limited to this. The detailed configuration and detailed operation of each device constituting the system can be changed as appropriate without departing from the spirit of the present invention.

  In the above embodiment, as the paper processing in the first paper processing apparatus 20, the case where the image is read one side at a time for the evaluation of the image quality has been described. However, the same paper is transported a part of the transport path twice or more times. As long as the sheet processing apparatus has a circulation path, the sheet processing performed in the apparatus is not limited. For example, the paper processing for processing the front surface and the back surface of the paper may be a coating processing for applying paint to the paper.

  In addition, when the conveyance speed of the sheet in the first sheet processing apparatus 20 is not constant, the position of the sheet conveyed in the first sheet processing apparatus 20 may be estimated based on the changing speed.

  In the above description, an example in which a ROM is used as a computer-readable medium storing a program for executing each process is disclosed, but the present invention is not limited to this example. As other computer-readable media, a non-volatile memory such as a flash memory and a portable recording medium such as a CD-ROM can be applied. A carrier wave may be applied as a medium for providing program data via a communication line.

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 12 Control part 14 Image forming part 17 Conveying part 18 Storage part 20 1st paper processing apparatus 22 Control part 23 Inline sensor 24 Conveying part 25 Storage part 26 Circulation path 26A Inversion mechanism 100 Image forming system

Claims (8)

An image forming system comprising: an image forming apparatus; and a sheet processing apparatus connected to a downstream side of the image forming apparatus in a sheet conveying direction,
The paper processing apparatus includes:
A paper processing unit that performs predetermined paper processing on the paper conveyed from the image forming apparatus;
A circulation path for transporting the paper that has passed through the paper processing unit to the paper processing unit again;
With
The image forming apparatus includes:
An image forming unit for forming an image on paper;
The position of the sheet conveyed in the sheet processing apparatus is estimated, and the image is formed so that the image-formed sheet does not collide with the sheet conveyed in the sheet processing apparatus based on the estimation result. A control unit for controlling the timing of sending the formed paper to the paper processing device;
An image forming system comprising:   The control unit is configured to control a conveyance speed of the sheet in the sheet processing apparatus, a timing at which the sheet conveyed in the sheet processing apparatus is sent to the sheet processing apparatus, and a sheet of the sheet conveyed in the sheet processing apparatus. The image forming system according to claim 1, wherein the position of a sheet being conveyed in the sheet processing apparatus is estimated based on a size and a length of the circulation path.   The control unit is at least necessary in the sheet processing apparatus, the estimated position of one or a plurality of sheets in the sheet processing apparatus, the size of the sheet to be sent next to the sheet processing apparatus, and the sheet processing apparatus. The image forming system according to claim 1, wherein a timing at which the image-formed sheet is sent to the sheet processing apparatus is controlled based on a sheet interval and a margin due to an estimation error.   The control unit sends out the image-formed sheet to the sheet processing apparatus so that the image-formed sheet is inserted between a plurality of sheets conveyed in the sheet processing apparatus. The image forming system according to claim 1, wherein the image forming system is controlled. The paper processing unit reads images formed on both sides of the paper one side at a time,
The image forming system according to claim 1, wherein the sheet processing apparatus includes an evaluation unit that evaluates image quality based on the read image. A sheet processing unit that performs predetermined sheet processing on a sheet, and a circulation path for transporting the sheet that has passed through the sheet processing unit to the sheet processing unit again. An image forming apparatus connected to
An image forming unit for forming an image on paper;
The position of the sheet conveyed in the sheet processing apparatus is estimated, and the image is formed so that the image-formed sheet does not collide with the sheet conveyed in the sheet processing apparatus based on the estimation result. A control unit for controlling the timing of sending the formed paper to the paper processing device;
An image forming apparatus comprising: A sheet processing unit that performs predetermined sheet processing on a sheet, and a circulation path for transporting the sheet that has passed through the sheet processing unit to the sheet processing unit again. Is a paper transport method in an image forming apparatus for forming an image on a paper,
Estimating the position of the sheet being conveyed in the sheet processing apparatus;
Controlling the timing at which the image-formed paper is sent to the paper processing device so that the image-formed paper does not collide with the paper being conveyed in the paper processing device based on the estimation result; ,
Conveying method including: A sheet processing unit that performs predetermined sheet processing on a sheet, and a circulation path for transporting the sheet that has passed through the sheet processing unit to the sheet processing unit again. Connected to the computer of the image forming apparatus that forms an image on paper,
The position of the sheet conveyed in the sheet processing apparatus is estimated, and the image is formed so that the image-formed sheet does not collide with the sheet conveyed in the sheet processing apparatus based on the estimation result. A program for causing a formed sheet to function as a control unit that controls the timing of sending the formed sheet to the sheet processing apparatus.

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