JP2006021868A - Image forming system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming system, capable of preventing waste of recording paper and damaging a device due to double feed. <P>SOLUTION: This image forming system 101 is provided with double feed detecting parts 15 and 25 to detect double feed of recording paper, and a first passage changing part 26a and a second passage changing part 26b to change carrying passages depending if double feed is detected or not. In the image forming system 101, the carrying passage without including a post-process is taken at the time of double feed. Reprinting is executed in accordance with the paper when the double feed is detected. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming system.

In an image forming system including an image forming apparatus such as a copying machine or a printer that forms an image on recording paper and a post-processing device that performs post-processing such as punch holes, stapling, folding processing, and sorting on the image-formed recording paper, When recording paper is being fed or transported, it may fall into a double feed state for some reason. Here, the double feed state means that two or more sheets cannot be separated one by one and are conveyed into the apparatus.
When the recording paper is transported and post-processed in the double feed state, the double fed recording paper may have a thickness outside the specification, which causes a problem.
In order to solve the problems related to the double feed, for example, when a double feed is detected, the paper is conveyed to a double feed tray, and a part of the paper is cut by a cutter so that it cannot be reused (patent For example, a technique (see Patent Document 2) in which punched holes are made in an invalid processing section and the paper cannot be reused is known.
JP-A-7-223757 JP-A-9-259227

Certainly, the above technique is an effective technique in that the multi-fed recording paper cannot be reused to prevent double feeding. However, it has not been sufficient in terms of preventing problems caused by feeding a recording sheet whose thickness is out of standard due to double feeding to the post-processing apparatus.
Further, in the case of post-processing such as stapling in which post-processing is performed for each copy, the entire copy is wasted due to double feeding. In addition, it is uneconomical because the user has to check the re-printed portion later and perform reprinting.

  Accordingly, an object of the present invention is to provide an image forming system that prevents waste of recording paper due to double feeding, labor of reprinting, and damage to the apparatus.

  In order to solve the above-described problems, the invention described in claim 1 is directed to an image forming apparatus that performs image forming processing on a recording medium based on image data, and a recording medium after image formation discharged from the image forming apparatus. A post-processing device that performs processing and outputs, and transporting means for transporting the recording medium and discharging it to a predetermined discharge destination for performing the image forming process and the post-processing; A multi-feed detection unit for detecting a multi-feed state at the time of conveyance; a conveyance path switching unit for changing a conveyance path of the recording medium after the image formation in a direction in which the post-processing is not performed according to the multi-feed state; It is characterized by having.

  According to a second aspect of the present invention, in the first aspect, the post-processing includes a process of inserting a predetermined medium into the recording medium after the image formation every predetermined number of sheets, and the double feed detection The means detects the double feed state of the medium to be inserted, and the transport path switching means changes the transport path of the medium to be inserted in a direction in which the post-processing is not performed according to the double feed state. It is characterized by.

  The invention according to claim 3 is the invention according to claim 1, wherein the post-processing is any one of staple processing, bookbinding processing, gluing processing, punching processing, folding processing, cutting processing, sorting processing, or a combination thereof. It is characterized by including.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, post-processing control is performed so as not to perform post-processing of the recording medium after the image formation according to the multi-feed state. It has the means.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the image forming apparatus further includes a reprinting unit that re-forms image formation of the double feed page detected by the double feed detection unit. To do.

  According to the first aspect of the present invention, since the double-fed recording paper is not sent to the post-processing apparatus, it is possible to prevent paper jams due to double-fed in advance. Further, in a binding process performed in units of copies, it is possible to prevent extra recording paper from being mixed in due to double feeding, and resources can be used effectively.

  According to the second aspect of the present invention, the number of sheets is a predetermined number. For example, a paper jam or an excess can be detected by detecting and discharging a predetermined multi-feed to be inserted into a section or a chapter. Can be prevented from being inserted and processed.

  According to the invention described in claim 3, paper jamming due to double feeding is prevented even in any of staple processing, bookbinding processing, gluing processing, punching processing, folding processing, cutting processing, sorting processing, or combined post-processing. can do.

  According to the fourth aspect of the present invention, it is possible to prevent in advance damage to the apparatus caused by post-processing a recording sheet having a thickness exceeding the standard by double feeding.

  According to the fifth aspect of the present invention, it is possible to save the trouble of the user confirming later and printing again by reprinting when double feeding is performed. Further, when printing for each copy, only the double-fed pages are reprinted, so that the others are not wasted.

[First Embodiment]
An image forming system 101 according to the present invention will be described in detail with reference to the drawings. However, the scope of the present invention is not limited to the illustrated examples.

FIG. 1 shows the overall configuration of an image forming system 101 as an image forming system of the present invention. The image forming system 101 is communicatively connected to a LAN (Local Area Network) or the like to which a PC (Personal Computer) or the like is connected via a communication network 4, and is capable of copying on a recording sheet using a scanner or printing using data communication. A network composite comprising an image forming apparatus 1 having a function and a post-processing apparatus 2 connected to the image forming apparatus 1 by a communication cable 3 and performing various post-processing such as punching, folding processing, and stapling on the image-formed recording paper Machine.
Note that the image forming system 101 described above is configured to use the functions of the image forming apparatus 1 and the post-processing apparatus 2 in cooperation with each other, but may use each function alone.

  The image forming apparatus 1 includes a CPU 10, a display unit 11, an operation unit 12, a ROM 13, a RAM 14, a double feed detection unit 15, an image reading unit 16, an image forming unit 17, and an external I / F 18. It is electrically connected.

  The CPU 10 includes an internal RAM (Random Access Memory) (not shown), and sends a control signal to each unit according to various control programs stored in the ROM 13 (to be described later) using a predetermined area of the internal RAM or the RAM 14 (to be described later) as a work area. Overall control of the operation of the forming system 101 is performed.

  The display unit 11 includes a display such as an LCD (Liquid Crystal Display) and a CRT (Cathode Ray Tube), and displays image data on a display screen based on display data input from the CPU 10.

  The operation unit 12 is a pressure-sensitive (resistance film pressure type) touch panel or the like in which transparent electrodes are arranged in a grid pattern, and is installed on the display screen of the display unit 11 described above. The operation unit 12 outputs an operation signal input from the touch panel to the CPU 10. The transparent electrode preferably has a high light transmittance from the viewpoint of visibility.

  The ROM 13 is a non-volatile memory or a flash read-only memory that can be rewritten for updating. The ROM 13 is an initial startup program corresponding to the CPU 10, a basic operation program for controlling each unit, and various processes. This is a storage area for storing processing programs and the like.

  The RAM 14 is a volatile memory composed of, for example, an SDRAM (Synchronous Dynamic Random Access Memory), and forms a memory area for developing various data when the CPU 10 executes various processes.

  The double feed detection unit 15 includes a light emitter that irradiates the recording paper with light and a light receiving unit that measures the transmitted light in the recording paper conveyance path (both not shown). Double feed is detected by measuring the thickness, and a detection signal is output to the CPU 10. Note that the multifeed detection unit 15 is not limited to the above. For example, since the recording paper is a substance that does not easily transmit light or a photosensitive film that changes in quality due to light, recording is performed from the displacement of the carry-out roller. The configuration may be such that double feed is detected by measuring the thickness of the paper.

  The image reading unit 16 includes a scanner below a transparent contact glass on which a document is placed. The image reading unit 16 reads the document sent from the ADF (automatic paper feeding mechanism) to the contact glass by the scanner and acquires the image data. And output to the CPU 10. The scanner is composed of a light source, a lens, a CCD (Charge Coupled Device), and the like. The reflected light of the light scanned from the light source to the original is imaged by the lens and photoelectrically converted by the CCD to obtain image data.

The image forming unit 17 includes an image writing unit 17a including an exposure unit, a photosensitive drum, and a developing unit, and a fixing unit 17b that fixes the written image on a recording sheet. Based on a print instruction from the CPU 10 and print data. Then, an electrostatic latent image is formed on the surface of the photosensitive drum by the exposure unit. Then, the image forming unit 17 forms a toner image on the surface of the photosensitive drum by attaching the toner by the developing unit, transfers the toner image onto a recording sheet, fixes the image by the fixing unit 17b, and outputs the toner image.
In this embodiment, an example in which an electrophotographic method is applied will be described. However, the present invention is not limited to this, and other printing methods such as an ink jet method and a thermal sublimation method may be applied.

  The external I / F 18 is a communication module such as a communication module capable of data communication with an external device by serial communication, a network interface card (hereinafter referred to as NIC), a modem, or the like, and a post-processing device according to an instruction from the CPU 10 2 and the data on the LAN connected to the communication network 4.

  The post-processing device 2 includes a CPU 20, a ROM 21, a RAM 22, an input unit 23, an output unit 24, a double feed detection unit 25, a first path switching unit 26 a, a second path switching unit 26 b, and a post-processing unit 27. It is electrically connected to each other via.

  The CPU 20 includes an internal RAM (not shown), and controls signals to each unit according to various control programs stored in the ROM 21 described later and a control instruction from the image forming apparatus 1 using a predetermined area of the internal RAM or RAM 22 described later as a work area. To control the overall operation of the post-processing device 2.

  The ROM 21 is a non-volatile memory or a rewritable flash memory for updating, and stores an initial startup program corresponding to the CPU 20, a basic operation program for controlling each unit, a processing program for performing various processes, and the like. It is an area.

  The RAM 22 is a volatile memory composed of, for example, SDRAM, and forms a memory area for developing various data when the CPU 20 executes various processes.

  The input unit 23 includes a plurality of conveyance roller pairs mainly including a driving roller and a driven roller, and is a conveyance path from reception of a recording sheet to the post-processing unit 27. The input unit 23 is a recording sheet for performing post-processing for inserting a predetermined sheet into a predetermined number of sheets such as for each copy or for each recording sheet discharged from the image forming apparatus 1 after image formation. Is sent to the post-processing unit 27 described later.

  The output unit 24 includes a plurality of conveyance roller pairs, and is a conveyance path that discharges a recording sheet that has undergone post-processing or no post-processing to a predetermined tray.

  The double feed detection unit 25 is on the insertion sheet conveyance path for performing the post-processing for inserting the predetermined sheet described above, and measures the thickness from the amount of received light that is irradiated and transmitted or the displacement of the conveyance roller. Then, double feed is detected and a detection signal is output to the CPU 20.

  The first path switching units 26a and 26b are a detection sensor that detects the position of the recording sheet in the middle of the input unit 23 and a switching gate that selectively switches the conveyance path by changing the position of the conveyance roller (both illustrated). In response to an instruction from the CPU 20, the recording paper to be conveyed is sent to a predetermined conveyance path to be described later.

  The post-processing unit 27 binds a plurality of image-formed recording media in a bundle, stapling processing, booklet processing, binding processing such as gluing processing, punching processing, folding processing, cutting processing, sorting processing Etc. and then output. The post-processing unit 27 may perform a combination of the above processes.

  The external I / F 28 is a communication module capable of data communication with an external device by serial communication, and transmits / receives data to / from the image forming apparatus 1.

  Next, a conveying unit in the image forming system 101, which shows the configuration of the conveying paths r1 to r8 from the feeding of the recording paper to the post-processing after image formation and output, shows the recording paper conveying path. Will be described with reference to FIG.

The image forming apparatus 1 includes a paper feed unit 31a and a paper feed unit 31b that distinguish and store recording paper on which an image is formed according to a predetermined size, a pickup roller that takes in the recording paper from the above-described paper feeding unit, a transport roller, and a weight. A conveyance path r1 that includes a feed detection unit 15 and conveys recording paper to the image forming unit 17, an image forming unit 17 that includes an image writing unit 17a and a fixing unit 17b, and a recording that is fixed on the fixing unit 17b by a conveyance roller. And a conveyance path r2 for conveying the paper to the first path switching unit 26a.
In the image forming apparatus 1, the recording paper is transported from the transport path r1 to the image forming unit 17, and after the image forming process, is transported to the first path switching unit 26a through the transport path r2.

  The post-processing device 2 includes the above-described paper inserter 33 that takes in the insertion sheet, a conveyance path r8 that conveys the insertion sheet to the conveyance path r2 through the multifeed detection unit 25, and a recording sheet that is conveyed from the conveyance path r2. A first path switching unit 26a that selectively performs output to the transport path r4 transported to the post-processing unit 27 or output to the transport path r5 transported to the post-processing unit 27; The recording paper is fed from the staple unit 27c to the second path switching unit 26b that selectively outputs the conveyance path r7 that is conveyed to the punching unit 27a and the folding unit 27b that performs the folding process or the conveyance path r6 that is conveyed to the staple unit 27c that performs the staple process. An output tray 32a is configured.

  In the post-processing apparatus 2, the recording paper is output to the sub-tray 32b by the first path switching unit 26a, and the recording paper is output to the tray 32a by the second path switching unit 26b through the punch unit 27a and the stapling unit 27c. In some cases, the data is output to the tray 32a through the staple unit 27c.

In addition, although the punch parts 27a and 27b were a folding part and a punch part, the structure which performs a cutting process may be sufficient and it does not specifically limit to this. Similarly, the staple unit 27c is a staple unit, but may perform a binding process such as a booklet (bookbinding) process or a gluing process.
In general, it is desirable that post-processing to be performed for each recording sheet is arranged in the punch units 27a and 27b, and binding processing is arranged in the staple unit 27c.

In the image forming system 101, a position detection sensor is provided on each of the transport paths described above, and manages the transport position of the recording paper. The image forming system 101 manages image data to be transferred, information on post-processing to be performed, discharge tray information, paper type, and information on double feed detection for each recording sheet to be conveyed. Each unit to which the recording paper is conveyed performs each process according to the information.
Note that each piece of information managed here is stored in the RAM 14 or the RAM 22 and erased after all the processes are completed. However, for example, a configuration may be adopted in which the information is stored as a past history.

  Next, the conveyance process up to the recording paper conveyance path r2 in the image forming system 101 will be described with reference to the flowchart shown in FIG. The process described here includes each of steps S11 to S14 performed by the CPU 10.

  In response to an image forming instruction, recording paper is fed from the paper feeding units 31a and 31b and conveyed to the image forming unit 17 (step S11). In step S11, when post-processing for inserting a predetermined sheet is selected, the insertion sheet is simultaneously fed from the paper inserter 33.

After step S11, double feed detection processing is performed in the double feed detection unit 15 and the double feed detection unit 25 in step S12 as a double feed detection unit, and the image forming unit 17 performs transfer processing accompanying image formation (step S13). The fixing process (step S14) is performed, the recording sheet is output to the conveyance path r2, and the process ends.
It should be noted that the transfer / fixing process in steps S13 and S14 is not performed when double feeding is detected, but is transported as it is and is output to the transport path r2, so that toner can be saved. .

Here, the double feed detection process in step S12 will be described with reference to the flowchart shown in FIG.
First, in the double feed detection unit 15 or the double feed detection unit 25, double feed detection is performed when the recording paper passes (step S21), and if double feed is not detected (step S22: NO), the process ends.
In step S22, when double feeding is detected (step S22: YES), double paper information indicating that the recording paper being conveyed is double fed is added (step S23), and the process is terminated.

  Next, switching processing by the first path switching unit 26a as the transport path switching means will be described with reference to the flowchart shown in FIG. Each process described here includes each process of step S31 to step S36 performed by the CPU 10.

  First, in the image forming system 101, the recording paper is conveyed from the conveyance path r2, thereby confirming whether the output destination tray of the recording paper is the sub-tray 32b (step S31).

  After step S31, when the output destination of the recording paper is the sub-tray 32b (step S32: YES), the switching gate is switched to the conveyance path r4 that is the conveyance path to the sub-tray 32b (step S33), and the process is ended.

  In step S32, if the output destination of the recording paper is not the sub-tray 32b (step S32: NO), the recording paper double feed detection information is referred to (step S34), and the recording paper is conveyed by detecting double feeding. Is determined (step S35).

  If it is determined in step S35 that the recording paper has been detected as being double-fed (step S35: YES), the switching gate is switched to carry-out in the direction of the conveyance path r4 (step S33), and the process ends. In step S35, when it is determined that the recording paper is not detected to be double fed (step S35: NO), the switching gate is switched in the direction of the conveyance path r5 to be carried out from the post-processing unit 27 to the tray 32a (step S36). ),finish.

  As described above, the image forming system 101 detects the double feed for each recording sheet conveyed by the double feed detection unit 15 or the double feed detection unit 25, and sets the discharge direction of the recording sheet according to the result. The first path switching unit 26a switches from 27 to the tray 32a or the sub-tray 32b.

  Therefore, it is possible to output the recording paper in which double feeding is detected without passing through the post-processing unit, and it is possible to prevent problems such as paper jam in the post-processing unit due to double feeding. Further, it is possible to prevent the double-fed reusable recording paper from being reused by post-processing, and to suppress the cost due to double feeding.

[Second Embodiment]
Next, an image forming system 101 according to the second embodiment will be described. Since the image forming system 101 in the second embodiment of the present invention is substantially the same as the image forming system 101 in the first embodiment, the switching process by the second path switching unit 26b, which is a different part, is described with reference to FIG. This will be described with reference to the flowchart shown in FIG. Each process described here includes each process of Steps S41 to S46 performed by the CPU 10.

  First, the image forming system 101 confirms whether the recording paper is transported to the transport path r6 or the transport path r7 by transporting the recording paper from the transport path r5 (step S41).

  After step S41, when it is determined that the recording paper transport destination is the transport path r6 (step S42: NO), the switching gate is switched to the transport path r6, which is a transport path to be output from the staple unit 27c to the tray 32a. (Step S43), the process ends.

  If it is determined in step S42 that the recording paper transport destination is the transport path r7 (step S42: YES), the recording paper double feed detection information is referred to (step S44), and double feed is detected and transported. It is determined whether it is a recording sheet that is being printed (step S45).

  If it is determined in step S45 that the recording paper has been detected as being double fed (step S45: YES), the switching gate is switched to transport in the direction of the transport path r6 (step S43), and the process ends. If it is determined in step S45 that the recording paper is not detected to be double-fed (step S45: NO), the switching gate is switched to transport to the transport path r7 (step S46), and the process ends.

  As described above, the image forming system 101 switches the conveyance direction to the conveyance path r6 or the conveyance path r7 in accordance with the double feeding of the recording paper, thereby providing a conveyance path for performing a plurality of post-processing that more easily causes a paper jam. It can be avoided, and the stop of the process by it can be prevented.

[Third Embodiment]
Next, an image forming system 101 according to the third embodiment will be described. Since the image forming system 101 according to the third embodiment of the present invention is almost the same as the image forming system 101 according to the first and second embodiments, the recording paper, which is a different part, is sent to the post-processing unit 27. The processing at the time of arrival will be described with reference to the flowchart shown in FIG. Each process described here includes each process of Steps S51 to S54 performed by the CPU 10.

  First, in the image forming system 101, when the recording paper is conveyed to the post-processing unit 27, the double feed detection information of the recording paper is referred to (step S51), and it is determined whether the recording paper is the double feed detection paper (step S51). S52).

  If it is determined in step S52 that the paper is double feed detection paper (step S52: YES), the paper is discharged without performing post-processing (step S53), and the process ends.

  If it is determined in step S52 that the paper is not double feed detection paper (step S52: NO), the information related to the post-processing to be performed is referred to, post-processing corresponding thereto is performed, and the paper is discharged (step S54). .

  As described above, the image forming system 101 prevents the post-processing unit 27 from performing post-processing in response to double feeding of recording paper. Therefore, for example, when post-processing is performed for each part, it is possible to prevent the double-fed recording paper from being mixed with the normally transported recording paper and being post-processed, so that all of the recording paper is not wasted. In addition, it is possible to prevent problems caused by post-processing on the recording paper whose thickness exceeds the standard due to double feeding.

[Fourth Embodiment]
Next, an image forming system 101 according to the fourth embodiment will be described. Since the image forming system 101 according to the fourth embodiment of the present invention is substantially the same as the image forming system 101 according to the first to third embodiments, reprinting at the time of double feeding as reprinting means which is a different part. The process will be described with reference to the flowchart shown in FIG. Each process described here includes each process of Steps S61 to S66 performed by the CPU 10.

  First, the image forming system 101 sets whether to perform reprinting at the time of double feeding from referring to information stored in advance or an operation by a user (step S61).

  After step S61, input of image data and various print settings are performed, and image formation processing based on the input (step S62) and post-processing are performed (step S63). Whether or not there has been a double feed is determined with reference to the information relating to the double feed detection (step S64).

  If it is determined in step S64 that double feed has not been detected (step S64: NO), the process ends. If it is determined in step S64 that double feeding has been detected (step S64: YES), reprint settings are confirmed (step S65), and it is determined whether or not reprinting is to be performed (step S66).

  If it is determined in step S66 that reprinting is to be performed (step S66: YES), reprinting is instructed for the image data relating to the double-fed recording paper (step S67), and image forming processing (step S62). Then, the image forming process is performed again. If it is determined in step S66 that reprinting is not to be performed (step S66: NO), the process ends as it is.

  Note that in step S67, for example, in the case of a binding process in which post-processing performed on reprinted image data is performed in units of copies, information regarding the post-processing is changed so as not to perform post-processing. , “Please finish the reprinted paper in manual mode”, and a message prompting the user to post-process individually is displayed.

  As described above, the image forming system 101 performs reprinting after printing when there is a double feed of recording paper by setting in advance. Therefore, the image forming system 101 can perform multi-feed processing without stopping the processing. In addition, even when the image forming system 101 performs post-processing by printing in units of copies, the entire portion is not wasted by reprinting only the double feed portion.

[Modification]
Next, a modified example of the image forming system 101 according to the above-described fourth embodiment will be described. Since the modification described here is almost the same as that of the fourth embodiment, a process for determining re-printing for each page, which is a different part, and performing reprinting will be described with reference to the flowchart shown in FIG. To do. Each process described here includes each process of Steps S71 to S78 performed by the CPU 10.

  First, the image forming system 101 refers to information stored in advance or sets whether to perform reprinting at the time of multi-feed from an operation by the user (step S71).

  After step S71, input of image data and various print settings are performed, and an image forming process based on the input is performed for each page (step S72), conveyed to the post-processing apparatus (step S73), and recorded. It is determined whether or not the paper has been double fed (step S74).

If it is determined in step S74 that the recording paper has not been detected as a double feed (step S74: NO), it is determined whether all the pages in the section have been printed (step S78), and all the pages are printed. If not (step S78: NO), the process returns to step S62.
In step S78, when all pages are printed (step S78: YES), normal post-processing is performed as it is and the process is terminated.

  In step S74, when it is determined that the recording paper is the double-feed detected (step S74: YES), the reprint setting is confirmed (step S75), and it is determined whether or not reprinting is performed (step S76). ).

If it is determined in step S76 that reprinting is to be performed (step S76: YES), reprinting is instructed after the multi-fed recording paper is discharged to a predetermined tray by resetting the discharge destination tray information. (Step S77), the process returns to the image forming process (Step S72), and the same image forming process as that of the double-fed recording paper is performed again. If it is determined in step S76 that reprinting is not performed (step S76: NO), the process proceeds to step S78.
In addition, it is preferable that the resetting of the discharge destination tray information in step S77 is a tray different from the preset discharge tray.

As described above, the image forming system 101 performs the post-processing by performing re-printing after discharging the multi-fed paper when the recording paper is multi-fed by presetting. Therefore, even when the image forming system 101 performs post-processing by printing in units of copies, it is not necessary to re-process the post-detected portion later.

1 is a diagram illustrating an internal configuration of an image forming system 101 according to the present invention. FIG. 3 is a diagram illustrating a recording paper conveyance path of the image forming system 101 according to the present invention. (A) is a flowchart for explaining conveyance of recording paper in the image forming system 101, and (b) is a flowchart for explaining double feed detection processing in the image forming system 101. (A) is a flowchart explaining the switching process in the 1st path | route switching part 26a, (b) is a flowchart explaining the switching process in the 2nd path | route switching part 26b. (A) is a flowchart for explaining processing for switching the presence or absence of post-processing at the time of double feeding in the image forming system 101, and (b) is a flowchart for explaining reprinting processing at the time of double feeding in the image forming system 101. is there. 6 is a flowchart for describing processing for performing reprinting by determining double feeding for each page in the image forming system 101.

Explanation of symbols

101 image forming system 1 image forming apparatus 2 post-processing apparatus 3 communication cable 4 communication network 10 CPU
11 Display unit 12 Operation unit 13 ROM
14 RAM
15 Double Feed Detection Unit 16 Image Reading Unit 17 Image Forming Unit 17a Image Writing Unit 17b Fixing Unit 18 External I / F
19 Bus 20 CPU
21 ROM
22 RAM
23 Input unit 24 Output unit 25 Double feed detection unit 26a First path switching unit 26b Second path switching unit 27 Post-processing unit 27a Punch unit 27b Folding unit 27c Staple unit 28 External I / F
29 Bus 31a Paper Feed Unit 31b Paper Feed Unit 32a Tray 32b Sub Tray 33 Paper Inserter

Claims (5)

An image forming apparatus that performs an image forming process on a recording medium based on image data, and a post-processing apparatus that performs post-processing and outputs the recording medium after image formation discharged from the image forming apparatus,
Conveying means for conveying the recording medium to perform the image forming process and the post-processing and discharging the recording medium to a predetermined discharge destination;
A double feed detecting means for detecting a double feed state during conveyance of the recording medium;
A conveyance path switching means for changing a conveyance path of the recording medium after the image formation in a direction in which the post-processing is not performed according to the multi-feed state;
An image forming system comprising: The post-processing includes a process of inserting a predetermined medium into the recording medium after the image formation every predetermined number of sheets,
The double feed detecting means detects a double feed state of the inserted medium,
The image forming system according to claim 1, wherein the transport path switching unit changes the transport path of the inserted medium in a direction in which the post-processing is not performed according to the multi-feed state.   2. The image forming system according to claim 1, wherein the post-processing includes any one of a stapling process, a bookbinding process, a gluing process, a punching process, a folding process, a cutting process, and a sorting process, or a combination thereof.   4. The image forming system according to claim 1, further comprising a post-processing control unit configured to perform control so that post-processing of the recording medium after the image formation is not performed according to the multi-feed state. .   5. The image forming system according to claim 1, further comprising a reprint unit configured to perform image formation of the double feed page detected by the double feed detection unit again.

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