JP2017146508A - Image forming system and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming system capable of appropriately determining an execution result of blank sheet cleaning.SOLUTION: An image forming system 100 has: a conveyance part conveying recording materials along a conveyance path; an image forming part; a fixation part; an inversion part; a determination part; and a control part. The inversion part can invert a front and back of a recording material on the conveyance path. The determination part determines whether or not blank sheet cleaning to be performed by passing the recording material through the conveyance path is necessary when conveyance abnormality has occurred to the recording material. The control part controls the inversion part and determines whether or not to invert the recording material on the basis of a printing state of at least one surface of the recording material when the blank sheet cleaning is determined to be necessary and the blank sheet cleaning is performed by conveying at least one recording material remaining in the conveyance path.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image forming system and an image forming method.

  In the image forming system, when a jam occurs in the paper transport path, the paper remaining in the transport path other than the paper that caused the jam can be removed from the paper discharge tray or the like before the paper transport is stopped. A technique called pre-purge for transporting to a position is known. By performing the pre-purge, it is possible to reduce the number of sheets remaining in the apparatus, and it is possible to reduce the burden of jam handling by the user such as a sheet removing operation.

  Also, in the image forming system, unfixed toner may remain in the apparatus when a jam occurs around the fixing unit that fixes the toner to the paper. If unfixed toner remains, it is not preferable because it adheres to the conveyed paper and causes stains on the printed matter. Therefore, there is also known a technique called white paper cleaning in which, after the jam is resolved, a sheet that is not used as a printed material is passed through a conveyance path, and unfixed toner is attached to the sheet to perform cleaning (see Patent Document 1).

JP 2005-234442 A

  In the image forming system described in Patent Document 1, it is conceivable that blank paper cleaning is performed with the image-formed paper remaining in the image forming system, depending on the timing at which a jam occurs. This is because even if an image is formed on a sheet, if the image has already been fixed in the fixing unit, it is possible to clean the other fixing unit on the downstream side with the sheet itself. is there.

  However, the execution result of the blank paper cleaning is determined by checking the degree of toner adhesion to the discharged paper. Therefore, when blank paper cleaning is performed using an image-formed sheet as described above, it may not be possible to determine whether the toner adhered to the surface of the sheet on which the image has been formed is due to the image or has been adhered by cleaning. This causes a problem because the execution result of the cleaning cannot be properly determined. In particular, when the printing rate of the image formed on the paper surface is high, this problem becomes significant.

  The present invention has been made in view of the above circumstances, and an image forming system and an image forming method that can appropriately determine the execution result of blank paper cleaning when performing blank paper cleaning using paper remaining in the image forming system. I will provide a.

  The above object is achieved by the following means.

  (1) A conveying unit that conveys a recording material along a conveying path, an image forming unit that forms an image on the conveyed recording material, and heating and pressurizing the recording material on which the image is formed, The fixing unit for fixing the recording material, the reversing unit capable of reversing the front and back of the recording material on the conveyance path, and cleaning by passing the recording material through the conveyance path when a recording material conveyance abnormality occurs. A determination unit that determines whether or not blank paper cleaning is required; and when the blank paper cleaning is performed by transporting at least one recording material remaining in the transport path and performing the blank paper cleaning. An image forming system including: a control unit that determines whether to reverse the recording material by controlling the reversing unit based on a printing state of at least one surface.

  (2) The control unit determines whether the coverage of one surface of the recording material used for the blank paper cleaning is higher than a predetermined threshold as the printing state, and determines that the recording material is reversed when the coverage is high. The image forming system according to (1), wherein when it is not high, it is determined that the image is not reversed.

  (3) The printing state is determined on one surface of the recording material used for the blank paper cleaning, and the other surface of the recording material on which the printing state is not determined has a blank paper or a coverage equal to or less than a predetermined threshold (1) Or the image forming system as described in (2).

  (4) When the control unit performs the blank paper cleaning with a plurality of the recording materials, both sides of the conveyance path where the surface of the blank paper or the surface whose coverage is equal to or less than a predetermined threshold is opposed to the paper surface at least once. The image forming system according to (3), wherein the reversing unit is controlled so as to pass through a portion to be cleaned of the blank paper on the conveyance path.

  (5) In the case where the blank sheet cleaning is performed with a plurality of the recording materials, the control unit determines whether or not the recording material located on the most upstream side in the transport path is reversed, and the other recording materials The image forming system according to any one of (1) to (4), wherein the image is not inverted.

  (6) When performing the blank paper cleaning with a plurality of the recording materials, the control unit determines whether to invert every other sheet of the plurality of recording materials, or any one of the above (1) to (4) The image forming system according to one.

  (7) When performing the blank paper cleaning with a plurality of the recording materials, the control unit does not reverse the predetermined number of the recording materials positioned on the downstream side in the conveyance path, and the remaining recording materials The image forming system according to any one of (1) to (4), wherein it is determined whether or not every other sheet is reversed.

  (8) When the control unit receives an instruction to additionally perform the second blank paper cleaning after executing the first blank paper cleaning with the predetermined number of recording materials, the control unit carries the first blank paper cleaning. If it is determined whether or not the recording material on the most upstream side is to be reversed, the first blank paper is not reversed and the recording material on the most downstream side conveyed in the second blank paper cleaning is not reversed. If it is not determined whether to invert the recording material on the most upstream side conveyed in the cleaning, it is determined whether to invert the recording material on the most downstream side conveyed in the second blank paper cleaning. The image forming system according to any one of (1) to (7) above.

  (9) When the control unit receives an instruction to additionally perform the second blank paper cleaning after performing the first blank paper cleaning with a predetermined number of the recording materials, The image forming system according to any one of (1) to (8), wherein the image forming system is conveyed as a set and determines whether one of the one set is not reversed and the remaining one is reversed.

  (10) When the control unit receives an instruction to additionally perform the second blank paper cleaning after executing the first blank paper cleaning with the predetermined number of the recording materials, the conveyance unit faces the sheet surface. An instruction as to whether additional blank paper cleaning is necessary is received on either side of the path, and it is determined whether or not the recording material should be reversed in consideration of the instruction when performing the second blank paper cleaning. The image forming system according to any one of (1) to (9) above.

  (11) When performing the blank paper cleaning, if the recording material does not remain in the transport path, the control unit transports a new recording material and executes the blank paper cleaning. For the recording material, the image forming system according to any one of (1) to (10), wherein it is not determined whether to reverse the recording material.

  (12) A conveying unit that conveys the recording material along the conveying path, an image forming unit that forms an image on the conveyed recording material, and heating and pressurizing the recording material on which the image is formed, A method executed in an image forming system having a fixing unit for fixing to a recording material and a reversing unit capable of reversing the front and back of the recording material on the conveyance path when a recording material conveyance abnormality occurs A determination step for determining whether or not blank paper cleaning is required to be performed by passing the recording material through the conveyance path; and at least one recording material remaining in the conveyance path when the blank sheet cleaning is determined to be necessary. When transporting and performing the blank paper cleaning, based on the printing state of at least one surface of the recording material, the reversing unit is controlled to determine whether to invert the recording material. An image forming method and a control step.

  According to the image forming system of the present invention, when at least one sheet remaining on the conveyance path is conveyed and blank paper cleaning is performed when a jam occurs, whether or not the sheet is reversed based on the printing state of at least one side. Judging. Thus, for example, both sides of the conveyance path can be cleaned with a surface in a printing state where it is easy to confirm the execution result of the blank sheet cleaning. Therefore, it is possible to appropriately determine the execution result of the blank paper cleaning.

1 is a diagram illustrating a schematic configuration of an image forming system according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating a hardware configuration of the image forming system illustrated in FIG. 1. 6 is a flowchart illustrating a procedure of processing executed when a jam occurs in the image forming system. FIG. 10 is a diagram showing an example of a screen displayed on the operation panel in the blank sheet cleaning number receiving process shown in step S106 of FIG. 3. 4 is a flowchart showing a procedure of blank sheet cleaning necessity determination processing shown in step S102 of FIG. 3. It is a flowchart which shows the procedure of the stop determination process shown by step S103 of FIG. It is a figure for demonstrating the example of the determination process of the necessity determination target of inversion shown by FIG.3 S107. It is a flowchart which shows the procedure of the necessity determination process of inversion shown by step S108 of FIG. It is a flowchart which shows the procedure of the additional blank sheet cleaning process shown by step S111 of FIG. FIG. 10 is a diagram showing an example of a screen displayed on the operation panel in the additional blank sheet cleaning execution confirmation process shown in step S501 of FIG. 9. 10 is a flowchart illustrating a procedure of determination processing for a reversal necessity determination target shown in step S503 of FIG. 9. FIG. 10 is a diagram showing another example of a screen displayed on the operation panel in the additional blank sheet cleaning execution confirmation process shown in step S501 of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. In addition, the dimensional ratios in the drawings are exaggerated for convenience of explanation, and may be different from the actual ratios.

  FIG. 1 is a diagram showing a schematic configuration of an image forming system according to an embodiment of the present invention. FIG. 2 is a block diagram showing a hardware configuration of the image forming system shown in FIG.

  As shown in FIGS. 1 and 2, the image forming system 100 according to the present embodiment includes a main machine 110, a first relay apparatus 120, a sub machine 130, a second relay apparatus 140, an image reading apparatus 150, and a post-processing apparatus 160. Have The main machine 110 and the sub machine 130 are image forming apparatuses. The image forming system 100 is a series tandem machine in which a main machine 110 that is two image forming engines and a sub machine 130 are connected in series. Each configuration will be described below.

<Main machine 110>
The main machine 110 is an image forming apparatus that controls the entire image forming system 100, and functions as a master unit of the serial tandem machine. For example, when performing double-sided printing, the main machine 110 forms an image on the first surface (front surface) of a sheet as a recording material used for printing.

  The main unit 110 includes a control unit 111, a storage unit 112, an operation panel 113, a paper transport unit 114, an image forming unit 115, a fixing unit 116, and a communication unit 117, which are connected via a bus for exchanging signals. Are connected to each other.

  The control unit 111 is a CPU (Central Processing Unit), and controls the above-described units and performs various arithmetic processes according to a program.

  The storage unit 112 stores a ROM (Read Only Memory) that stores various programs and various data in advance, a RAM (Random Access Memory) that temporarily stores programs and data as a work area, and stores various programs and various data. It consists of a hard disk.

  The operation panel 113 includes a touch panel, a numeric keypad, a start button, a stop button, and the like, and is used for displaying various information and inputting various instructions.

  The paper transport unit 114 transports paper as a recording material used for printing. The sheets are stored in the sheet feeding trays S1 and S2, and are conveyed one by one to the image forming unit 115 along the conveying path 114a in the main machine 110 by a sheet feeding mechanism provided in the sheet feeding tray. Alternatively, a paper feeding device (not shown) may be connected upstream of the main machine 110 and paper may be supplied from the paper feeding device. A plurality of line sensors are provided as paper sensors at various locations on the conveyance path 114a. Each paper sensor detects the presence of paper on the conveyance path at the installed location, and notifies the control unit 111 of the detection result.

  The image forming unit 115 forms a toner image based on various data as an image on a sheet by using a known image forming process such as an electrophotographic process including charging, exposure, development, transfer, and fixing processes. . When forming a toner image on a sheet, the image forming unit 115 acquires a coverage that is a ratio of the area of the toner image to the area of the sheet, and transmits information indicating the acquired coverage to the control unit 111.

  The fixing unit 116 fixes the toner image transferred onto the paper by heating it. For example, the fixing unit 116 presses a heating member, which is a heating source, to the pressure member. As a result, heat and pressure are applied to the paper at the fixing nip portion, and the toner image is melted and fixed.

  The communication unit 117 is an interface for communicating with other devices. The communication unit 117 includes various setting values, information necessary for operation control, and paper by a paper sensor between the first relay device 120, the sub-device 130, the second relay device 140, the image reading device 150, and the post-processing device 160. Various kinds of information such as detection information of the image and information indicating the occurrence of the jam are transmitted / received.

  The control unit 111 controls the paper transport unit 114 to transport the paper in the main machine 110. Further, the control unit 111 detects, as a detection unit, a jam that has occurred in the main machine 110 based on the detection result of the paper by each paper sensor. For example, the control unit 111 detects the occurrence of a jam when the time from when each paper sensor detects the leading edge of the paper until the trailing edge of the paper is detected exceeds a preset threshold. The control unit 111 is a device other than the main device 110 in the image forming system 100 (hereinafter also referred to as “another device”), a first relay device 120, a sub device 130, a second relay device 140, and an image reading device. 150 and the post-processing device 160 communicate with each other and receive information indicating the occurrence of a jam in another device.

  Further, when a jam occurs in the image forming system 100, the control unit 111 determines whether or not blank paper cleaning is necessary before stopping the operation of the image forming system 100. Here, blank paper cleaning refers to the inside of the image forming system 100 by allowing a sheet to pass through a conveyance path without performing image formation processing, and collecting and collecting dirt such as unfixed toner existing in the conveyance path on the sheet. This is a process for performing the cleaning. A portion to be subjected to blank paper cleaning is a conveyance path or a fixing unit disposed on the conveyance path. Further, the white paper refers to a paper in which an image or the like is not formed.

  The paper used for blank paper cleaning is not necessarily a complete blank paper. Even on a sheet on which an image or the like is formed, unfixed toner can be adhered, and therefore cleaning itself is possible. However, the execution result of the blank paper cleaning is determined by checking the degree of toner adhesion to the discharged paper. Therefore, in order to appropriately determine the execution result of the blank paper cleaning, it is preferable that the paper used for the blank paper cleaning has a low coverage (printing rate) even if a blank paper or an image is formed. Here, the blank sheet cleaning is performed on both sides of the conveyance path facing the sheet surface. Therefore, for example, even when a high-coverage image is formed on the first side of the paper, if the second side is in a state where a blank page or a low-coverage image is formed, blank page cleaning is performed on the second side. The result can be judged appropriately. In other words, the execution result of blank sheet cleaning can be appropriately determined for the side of the conveyance path that faces the second surface of the sheet.

  When blank paper cleaning is unnecessary, the control unit 111 discharges paper remaining on the conveyance path other than the jam-caused paper, which is the paper causing the jam, by a pre-purge process. The pre-purge process is a process that, when a jam occurs, discharges paper remaining on the transport path to a nearby paper discharge tray or the like or transports it to a position where it can be easily removed by the user before stopping the transport of the paper. .

  On the other hand, when the blank paper cleaning is necessary, the control unit 111 stops the paper positioned upstream from the portion where the blank paper cleaning is necessary in the conveyance path, and pre-purges other papers other than the stopped paper.

  Further, after the pre-purge is completed, the control unit 111 stops the operation of the image forming system 100 so that the user can perform jam processing such as removal of jam-caused paper. After the jam-caused paper is removed and the jam is resolved, the control unit 111 receives a designation of the number of sheets to be cleaned from the user. The control unit 111 determines whether or not it is necessary to invert the paper used for blank paper cleaning. The control unit 111 carries out blank sheet cleaning by conveying the sheet used for blank sheet cleaning by automatic purge processing while inverting it as necessary. The automatic purge process is a process for automatically conveying and discharging the paper remaining in the image forming system 100 after the jam is resolved.

<First relay device 120>
The first relay device 120 is connected between the main machine 110 and the sub machine 130, reverses the sheet output from the main machine 110 as necessary, and conveys it to the sub machine 130.

  The first relay device 120 includes a control unit 121, a storage unit 122, a paper transport unit 123, a reversing unit 124, a paper discharge unit 125, and a communication unit 126, which are mutually connected via a bus for exchanging signals. It is connected to the. In addition, since the memory | storage part 122 and the communication part 126 have the same function as the memory | storage part 112 and the communication part 117 of the main machine 110, in order to avoid duplication of description, the description is abbreviate | omitted.

  The control unit 121 performs control of the above-described components and various arithmetic processes according to a program. The control unit 121 controls the paper transport unit 123 and the reversing unit 124 based on an instruction from the main machine 110 to transport and reverse the paper.

  The paper transport unit 123 transports the paper supplied from the main machine 110 along the transport path 123 a in the first relay device 120. The paper transport unit 123 transports the paper to the reversing unit 124 in the case of double-sided printing according to the setting of the print job, and to the sub machine 130 without transporting the paper to the reversing unit 124 in the case of single-sided printing. Transport. In addition, the paper transport unit 123 transports the paper to the reversing unit 124 based on an instruction from the main machine 110, for example, when performing blank paper cleaning after a jam occurs. A plurality of line sensors are provided as paper sensors at various locations on the conveyance path 123a. Each sheet sensor detects the presence of a sheet on the conveyance path at the installed location, and notifies the control unit 121 of the detection result.

  The reversing unit 124 has a path branched on the transport path 123a, and transports the paper entered from the leading end side in the reverse direction and returns it to the transport path 123a from the rear end side. Is reversed. Further, the reversing unit 124 conveys the sheet to the paper discharge unit 125 based on an instruction from the main machine 110, for example, when performing a pre-purge process after a jam occurs.

  The paper discharge unit 125 is a sub-tray or stacker for discharging paper. For example, when a jam occurs on the downstream side of the first relay device 120, the image forming system 100 conveys the paper remaining upstream of the first relay device 120 to the paper discharge unit 125 as a pre-purge process. As a result, paper remaining in the image forming system 100 can be reduced, and the jam processing burden on the user is reduced.

  The control unit 121 detects a jam that has occurred in the first relay device 120 based on the detection result of the paper by the paper sensor. The control unit 121 transmits information indicating the occurrence of a jam in the first relay device 120 to the main machine 110 via the communication unit 126.

<Sub machine 130>
The sub machine 130 is an image forming apparatus that operates according to an instruction from the main machine 110, and functions as a child machine of the serial tandem machine. For example, the sub-machine 130 prints an image on the second side (back side) of the paper that is reversed in the first relay device 120 when performing double-sided printing.

  The sub-unit 130 includes a control unit 131, a storage unit 132, an operation panel 133, a paper transport unit 134, an image forming unit 135, a fixing unit 136, and a communication unit 137, which are connected via a bus for exchanging signals. Are connected to each other. The above-described configurations of the sub machine 130 have the same functions as the control unit 111, the storage unit 112, the operation panel 113, the paper transport unit 114, the image forming unit 115, the fixing unit 116, and the communication unit 117 of the main machine. Therefore, the description is omitted to avoid duplication of explanation.

  The control unit 131 communicates with the main unit 110 via the communication unit 137, and forms an image on the sheet while conveying the sheet along the conveyance path 134a based on an instruction from the main unit 110. In addition, the control unit 131 detects a jam that has occurred in the sub machine 130 based on the detection result of the paper by the paper sensor. The control unit 131 transmits information indicating the occurrence of a jam in the sub machine 130 to the main machine 110 via the communication unit 137.

<Second relay device 140>
The second relay device 140 is connected between the sub machine 130 and the image reading device 150, reverses the recording material output from the sub machine as needed, and conveys it to the image reading device 150.

  The second relay device 140 includes a control unit 141, a storage unit 142, a paper transport unit 143, a reversing unit 144, a paper discharge unit 145, and a communication unit 146, which are mutually connected via a bus for exchanging signals. It is connected to the. Each of the above-described configurations of the second relay device 140 has the same functions as the control unit 121, the storage unit 122, the paper transport unit 123, the reversing unit 124, the paper discharge unit 125, and the communication unit 126 of the first relay device 120. Therefore, the description is omitted to avoid duplication of explanation.

  The control unit 141 detects a jam that has occurred in the transport path 143a of the second relay device 140 based on the detection result of the paper by the paper sensor. The control unit 141 transmits information indicating the occurrence of a jam in the second relay device 140 to the main machine 110 via the communication unit 146.

<Image Reading Device 150>
The image reading device 150 is connected between the second relay device 140 and the post-processing device 160 and reads an image on a sheet conveyed from the second relay device 140. The image reading device 150 transmits the read information to the main machine 110, the sub machine 130, and the like.

  The image reading apparatus 150 includes a control unit 151, a storage unit 152, a paper transport unit 153, a reading unit 154, and a communication unit 155, which are connected to each other via a bus for exchanging signals. Note that the storage unit 152, the paper transport unit 153, and the communication unit 155 have the same functions as the storage unit 112, the paper transport unit 114, and the communication unit 117 of the main machine 110, and thus description thereof is omitted to avoid duplication of explanation. To do.

  The control unit 151 performs control of the above constituent elements and various arithmetic processes according to a program. The control unit 151 controls the reading unit 154 based on an instruction from the main machine 110 to read an image on a sheet.

  The reading unit 154 is a CCD (Charge Coupled Device) line sensor or a CIS (Contact Image Sensor), for example, and reads an image on a sheet conveyed on the conveyance path 153a.

  The control unit 151 detects a jam that has occurred in the conveyance path 153a of the image reading device 150 based on the detection result of the paper by the paper sensor. The control unit 151 transmits information indicating the occurrence of a jam in the image reading apparatus 150 to the main machine 110 via the communication unit 155.

<Post-processing device 160>
The post-processing device 160 performs post-processing such as folding and stapling on the paper conveyed from the image reading device 150, and outputs it as a printed matter.

  The post-processing device 160 includes a control unit 161, a storage unit 162, a paper transport unit 163, a post-processing unit 164, a paper discharge unit 165, and a communication unit 166, which are mutually connected via a bus for exchanging signals. It is connected to the. Note that the storage unit 162, the paper transport unit 163, and the communication unit 166 have the same functions as the storage unit 112, the paper transport unit 114, and the communication unit 117 of the main machine 110, and thus the description thereof is omitted to avoid duplication of description. To do.

  The control unit 161 performs control of the above-described components and various arithmetic processes according to a program. The control unit 161 controls the paper transport unit 163 and the post-processing unit 164 based on an instruction from the main machine 110 to perform paper transport and post-processing.

  The post-processing unit 164 includes a folding unit that performs folding processing on a sheet, a staple unit that staples a bundle of sheets and binds the bundle of sheets, and performs various post-processing necessary for outputting the sheet as a printed matter. Apply.

  The paper discharge unit 165 has a normal paper discharge tray for discharging the printed material and a sub-tray for discharging the waste paper. A plurality of sub-trays are provided, and the paper discharged by the pre-purge and the paper discharged by the white paper cleaning are discharged to independent sub-trays. Therefore, the user can clearly distinguish the paper discharged by the pre-purge from the paper discharged by the blank paper cleaning. As a result, the user can confirm the paper used for the blank paper cleaning, determine the remaining state of the dirt in the apparatus according to the degree of dirt on the paper, and judge the execution result of the blank paper cleaning.

  The control unit 161 detects a jam that has occurred in the conveyance path 163a of the post-processing device 160 based on the detection result of the paper by the paper sensor. The control unit 161 transmits information indicating the occurrence of a jam in the post-processing device 160 to the main machine 110 via the communication unit 166.

  The main machine 110, the first relay device 120, the sub machine 130, the second relay device 140, the image reading device 150, and the post-processing device 160 may each include components other than the above-described components. Alternatively, some of the above components may not be included.

<Outline of Processing in Image Forming System 100>
As described above, the image forming system 100 includes the main device 110, the first relay device 120, the sub-device 130, the second relay device 140, the image reading device 150, and the post-processing device 160, and these devices are connected. It is constituted by. The paper passes through each device in the order of the main machine 110, the first relay device 120, the sub-machine 130, the second relay device 140, the image reading device 150, and the post-processing device 160 from the right side to the left side in FIG. . The sheet on which the image is formed on the first surface by the main device 110 is reversed in the first relay device 120, and the image is formed on the second surface by the sub device 130. The paper on which the images are formed on the first side and the second side is reversed by the second relay device 140, the image is read by the image reading device 150, and conveyed to the post-processing device 160 for necessary post-processing. After being applied, it is output as a printed matter.

  Next, processing when a jam occurs in the image forming system will be described. Hereinafter, a case where a jam occurs in the vicinity of the fixing unit 136 of the sub machine 130 and the blank sheet cleaning is performed using the paper remaining in the main machine 110 will be described as an example.

  FIG. 3 is a flowchart showing a procedure of processing executed when a jam occurs in the image forming system. FIG. 4 is a diagram showing an example of a screen displayed on the operation panel in the blank sheet cleaning number receiving process shown in step S106 of FIG. The algorithm shown in the flowchart of FIG. 3 is stored as a program in the storage unit 112 of the main machine 110 and is executed by the control unit 111.

  As shown in FIG. 3, the image forming system 100 determines whether or not a jam has occurred in the image forming system 100 (step S101). Specifically, the control unit 111 of the main machine 110 checks whether or not a jam has occurred by checking whether or not the information indicating the occurrence of the jam has been received from each unit of the main machine 110 and other devices. Determine whether.

  If a jam has not occurred (step S101: NO), the image forming system 100 returns to the process of step S101 and repeats the process of step S101 until a jam occurs.

  If a jam has occurred (step S101: YES), the image forming system 100 determines whether blank paper cleaning is necessary after the jam is eliminated (step S102). Details of the process for determining whether or not blank paper cleaning is necessary will be described later.

  Subsequently, the image forming system 100 determines whether to stop each sheet remaining in the conveyance path of each apparatus (step S103). Specifically, when blank paper cleaning is unnecessary, the control unit 111 performs pre-purge on all the sheets that can be pre-purged among the sheets remaining on the conveyance path other than the jam-caused paper. On the other hand, when blank paper cleaning is necessary, the control unit 111 is a pre-purgeable sheet that is located on the upstream side of the jam-caused paper in the conveyance path and further upstream of the portion requiring blank paper cleaning. Even if there is, stop without pre-purge. The control unit 111 executes pre-purging for paper other than the paper to be stopped and paper that can be pre-purged. For example, when a jam occurs in the vicinity of the fixing unit 136 of the sub machine 130 and the blank paper around the fixing unit 136 needs to be cleaned, the control unit 111 can perform the pre-purge that remains in the main machine 110 or the like on the upstream side. The paper is stopped without pre-purge. Details of the stop determination process for determining whether or not to stop each sheet will be described later.

  Subsequently, the image forming system 100 determines whether or not the processing in step S103 has been completed for all sheets remaining in the conveyance path (step S104).

  If the processing has not been completed for all the sheets (step S104: NO), the image forming system 100 returns to the processing of step S103, and performs the processing of step S103 until the processing is completed for all the sheets.

  When the processing has been completed for all the sheets (step S104: YES), the image forming system 100 displays a message on the operation panel 113 or the like of the main device 110 to notify the user that jam processing is necessary. In addition, the image forming system 100 notifies that the paper stopped in the process of step S103 is not removed. For example, when blank paper around the fixing unit 136 of the sub machine 130 is required and the paper remaining in the main machine 110 is stopped without pre-purging, the image forming system 100 stops in the main machine 110. Notify that the paper is not removed.

  Subsequently, the image forming system 100 determines whether or not the jam processing by the user is completed (step S105). Specifically, the control unit 111 determines whether or not the jam processing has been completed based on the open / closed state of the door in each device, the detection status of the paper in the paper sensor, the completion operation from the user, and the like.

  If the jam processing has not been completed (step S105: NO), the image forming system 100 returns to the processing in step S105, and repeats the processing in step S105 until the jam processing is completed.

  When the jam processing is completed (step S105: YES), the image forming system 100 accepts the setting of the number of sheets for performing blank sheet cleaning (step S106). For example, the image forming system 100 displays a screen as shown in FIG. 4 on the operation panel 113 and accepts the setting of the number of sheets for performing blank sheet cleaning from the user. Note that a predetermined number of sheets may be used as the number of sheets to be subjected to blank sheet cleaning. The user may appropriately change the predetermined number according to the state of dirt, the required level of blank paper cleaning, and the like.

  Subsequently, the image forming system 100 determines a target sheet on which to determine whether reversal is necessary from among the number of sheets received in the process of step S105 (step S107). In the present embodiment, the image forming system 100 determines at least one sheet as a target sheet on which to determine whether reversal is necessary.

  For example, when a jam occurs in the vicinity of the fixing unit 136 of the sub machine 130 and blank paper cleaning is performed using the paper remaining in the main machine 110, an image is already formed on the first surface (upper surface) of the paper. It is possible. In this state, when the paper is transported as it is and the white paper cleaning is performed, an image is not formed on the second surface (lower surface) of the paper, so that the result of the white paper cleaning is appropriately set on the second surface of the discharged paper. I can judge. However, since an image has already been formed on the first surface of the paper, it is considered that the result of blank paper cleaning cannot be properly determined on the first surface of the discharged paper. Accordingly, among the two sides of the transport path, the result of blank sheet cleaning can be appropriately determined for the side (lower side) facing the second surface of the sheet, but the side (upper side) facing the first side of the sheet can be determined appropriately. It is conceivable that the result of blank paper cleaning cannot be properly determined. Therefore, in the present embodiment, at least one sheet is determined as a target of reversal necessity determination in step S108 described later so that the result of blank sheet cleaning can be appropriately determined on both sides of the conveyance path. Details of the process for determining the object of the necessity for reversal will be described later.

  Subsequently, the image forming system 100 determines whether or not it is necessary to invert the sheet determined as the necessity for reversal determination in the process of step S107 based on the printing state of at least one side of the sheet ( Step S108). Specifically, in the image forming system 100, a blank surface of a sheet or a surface whose coverage is equal to or less than a predetermined threshold is directed to both sides of the conveyance path at least once, and a portion to be cleaned on the conveyance path is determined. It is determined whether the paper needs to be reversed so as to pass.

  For example, when a jam occurs in the vicinity of the fixing unit 136 of the sub machine 130 and white paper cleaning is performed using paper remaining in the main machine 110, the second surface (lower surface) of the paper is white paper. Paper other than the paper determined as the necessity for reversal determination in the process of step S107 is conveyed without being reversed. The second surface of the non-inverted sheet is a blank sheet, and passes through a portion to be subjected to blank sheet cleaning with the blank sheet surface facing the lower side of the conveyance path. Accordingly, it is possible to appropriately determine the execution result of the blank sheet cleaning on the lower side of the conveyance path. In the present embodiment, whether or not to reverse the paper is determined in order to appropriately determine the execution result of the blank paper cleaning also on the upper side of the conveyance path. Here, since the second surface (lower surface) of the sheet is a blank sheet, it is possible to appropriately determine the execution result of the blank sheet cleaning also on the upper side of the conveyance path by reversing and conveying the sheet. In the present embodiment, in order to save processing time and power consumption when reversing the paper, the paper is reversed only when necessary based on the printing state of the first surface (upper surface) of the paper. Control. Details of the reversal necessity determination process will be described later.

  Subsequently, the image forming system 100 determines whether or not the processing in step S108 has been completed for the target paper (step S109).

  When the processing has not been completed for the target paper (step S109: NO), the image forming system 100 returns to the processing of step S108 and performs the processing of step S108 until the processing is completed for all the paper.

  When the processing is completed for the target paper (step S109: YES), the image forming system 100 transports the stopped paper again while reversing as necessary, and performs blank paper cleaning (step S110).

  Subsequently, the image forming system 100 performs an additional blank sheet cleaning process according to the execution result of the blank sheet cleaning performed in step S110 (step S111). The details of the additional blank paper cleaning process will be described later.

  When the additional blank sheet cleaning process ends, the image forming system 100 ends the process and stands by in preparation for the next image forming process or the like.

<Blank Paper Necessity Determination Process in Step S102>
FIG. 5 is a flowchart showing the procedure of the blank paper cleaning necessity determination process shown in step S102 of FIG. The algorithm shown in the flowchart of FIG. 5 is stored as a program in the storage unit 112 of the main machine 110 and is executed by the control unit 111.

  As shown in FIG. 5, in the image forming system 100, image formation (transfer) is started in the image forming units 115 and 135 due to a jam, and the fixing of the images is not completed in the fixing units 116 and 136. It is determined whether or not there is a sheet to be stopped (step S201).

  When there is one or more sheets to be stopped in a state where image fixing is not completed (step S201: YES), the image forming system 100 determines that blank sheet cleaning is necessary (step S202). For example, let us consider a case where an image has been transferred to a sheet, but a jam has occurred in a state where the fixing of the image has not been completed, and the sheet stops. In this case, the toner for forming the image exists on the paper in a state where the unfixed fluidity is high. If the user tries to remove the paper in this state, unfixed toner may adhere to the conveyance path, the fixing unit, and the like near the paper, and the inside of the apparatus may become dirty. Therefore, if there is a sheet that stops in a state where image fixing has not been completed, it is determined that blank paper cleaning is necessary in order to remove unfixed toner adhered in the apparatus after the jam processing.

  On the other hand, when there is no sheet to be stopped in a state where image fixing is not completed (step S201: NO), the image forming system 100 does not require blank paper cleaning because there is no unfixed toner in the apparatus. Judgment is made (step S203). For example, in the image forming units 115 and 135, even if an image is formed on a photosensitive drum, an intermediate transfer belt, or the like, if the image is not transferred to a sheet, it can be determined that blank sheet cleaning is unnecessary. In this case, the unfixed toner can be cleaned by a cleaning bias or a cleaning blade on the photosensitive drum or the intermediate transfer belt. Further, if the image transferred onto the sheet passes through the fixing units 116 and 136, it can be determined that there is no unfixed toner, and therefore no blank sheet cleaning is necessary. For example, when a jam occurs, there is a sheet between the image forming unit 135 and the fixing unit 136, and even when unfixed toner is present, the sheet is continuously conveyed downstream and the fixing unit 136 is moved. If it is allowed to pass, it may be determined that the blank paper cleaning is unnecessary.

<Stop determination process in step S103>
FIG. 6 is a flowchart showing the procedure of the stop determination process shown in step S103 of FIG. The algorithm shown in the flowchart of FIG. 6 is stored as a program in the storage unit 112 of the main machine 110 and is executed by the control unit 111. The image forming system 100 sequentially applies this processing to each sheet remaining on the conveyance path.

  As shown in FIG. 6, the image forming system 100 determines whether or not the target paper is a jam-caused paper (step S301). For example, when detecting the occurrence of a jam, the control unit 111 uses, as a jam-caused sheet, a sheet that is present on the most downstream side in the conveyance path among the sheets in which conveyance abnormality is detected based on the detection result of the sheet sensor of each device. I can judge.

  When the paper is a jam-caused paper (step S301: YES), the image forming system 100 stops the conveyance of the paper (step S302), and ends the stop determination process for the paper. The stopped jam-caused paper is removed by the user's jam processing after the paper conveyance of the image forming system 100 is stopped.

  If the paper is not jammed paper (step S301: NO), the image forming system 100 determines whether or not the paper is positioned upstream of the jammed paper in the transport path (step S303).

  When the paper is not located upstream from the jam-caused paper (step S303: NO), the image forming system 100 is located downstream from the jam occurrence position and is not affected by the jam, and the jam is eliminated. It is judged that it cannot be used for the blank paper cleaning after the operation. The image forming system 100 continues the conveyance and post-processing of the paper, and discharges it to a normal paper discharge tray such as the paper discharge unit 165 of the post-processing device 160 (step S304).

  If it is located upstream from the jam-caused paper (step S303: YES), the image forming system 100 determines whether or not the paper can be pre-purged (step S305). Specifically, the image forming system 100 determines whether there is a paper discharge tray or the like that can discharge the paper between the paper and the jam occurrence location. For example, when the jam occurrence location is the fixing unit 136 of the sub machine 130 and the paper is located in the main machine 110, the image forming system 100 transfers the paper to the paper discharge unit 125 of the first relay device 120. Since the sheet can be conveyed and discharged, it is determined that the sheet can be pre-purged. On the other hand, if the jam occurs at the fixing unit 136 of the sub machine 130 and the paper is located upstream of the fixing unit 136 in the sub machine 130, there is no paper discharge tray or the like that can discharge the paper. The forming system 100 determines that the sheet cannot be pre-purged.

  If the pre-purge is not possible (step S305: NO), the image forming system 100 proceeds to the process of step S302 and stops the conveyance of the sheet.

  If pre-purge is possible (step S305: YES), the image forming system 100 determines whether blank paper cleaning is required and whether the paper is positioned upstream of the portion where blank paper cleaning is required in the conveyance path. Is determined (step S306). Specifically, the image forming system 100 can determine whether blank paper cleaning is necessary by referring to the result of the process in step S102 of FIG. In addition, the image forming system 100 identifies the position of the paper that is determined to require blank paper cleaning in the processes of steps S201 and S202 in FIG. As a result, the image forming system 100 can determine whether or not the sheet is located on the upstream side of the portion requiring blank sheet cleaning.

  If blank paper cleaning is not required, or if the paper is not positioned upstream from the location where blank paper cleaning is required (step S306: NO), the image forming system 100 pre-purges the paper (step S307). Specifically, the image forming system 100 conveys the paper to a predetermined take-out position such as a paper discharge tray or a stacker. The predetermined take-out position is not limited to the paper discharge tray or the stacker, and may be a position at which the user can take out during jam processing, such as the vicinity of the door of the apparatus on the transport path.

  If blank paper cleaning is required and the paper is located upstream from the location where blank paper cleaning is required (step S306: YES), the image forming system 100 does not pre-purge the paper, The conveyance of the paper is stopped (step S308). Specifically, the control unit 111 of the main machine 110 communicates with the control unit of each device to control the paper conveyance unit of each device so that the conveyance of the paper is stopped without pre-purging the paper. Control. Here, the stop of conveyance is not limited to stopping immediate conveyance at a position where the sheet is present at that time. When the jam is resolved, the conveyance may be stopped anywhere as long as the sheet can be conveyed again in order to perform blank paper cleaning. For example, when the sheet is located at a position where the conveyance path is bent, the sheet may be stopped after being conveyed to an appropriate position in order to avoid folding or bending of the sheet. In addition, the paper on which image formation by the image forming unit is started, the paper being fixed by the fixing unit, and the like may be stopped after passing through the fixing unit.

<Determination Processing for Reversal Necessity Determination Target at Step S107>
FIG. 7 is a diagram for explaining an example of the process for determining the necessity for inversion shown in step S107 in FIG. 7A shows an example in which, for a plurality of sheets to be subjected to blank sheet cleaning, a sheet positioned on the most upstream side is determined as a determination target of reversal necessity and other sheets are not determined as reversal necessity determination targets. Show. (B) shows an example in which a plurality of sheets to be subjected to blank sheet cleaning are determined as targets for determining whether or not every other sheet is reversed. In (c), for a plurality of sheets to be subjected to blank sheet cleaning, a predetermined number of sheets positioned downstream are not subjected to the reversal necessity determination, and the remaining sheets are subjected to the reversal necessity determination for every other sheet. An example is given. (D) shows an example of a screen for accepting the setting of the number of sheets on the downstream side to be conveyed without being subjected to the reversal necessity determination when the process shown in the example of (c) is executed.

  In the example shown in FIG. 7A, the image forming system 100 determines the sheet P1, which is the most upstream sheet among the plurality of sheets P1 to P5 to be subjected to blank sheet cleaning, as the target of the reversal necessity determination. To do. The sheets P2 to P5, which are sheets other than the sheet P1, are not subjected to the necessity for reversal determination. Therefore, the papers P2 to P5 are cleaned as they are without being inverted.

  In the example shown in FIG. 7B, the image forming system 100 sets a plurality of papers P1 to P5 to be subjected to blank paper cleaning as a target for determining whether or not every other sheet is reversed. Therefore, the image forming system 100 determines the sheets P1, P3, and P5 as targets for determining whether or not to invert. The sheets P2 and P4 are not subjected to the necessity of reversal determination, and are subjected to blank sheet cleaning without being reversed.

  In the example shown in FIG. 7C, the number of sheets on the downstream side to be conveyed without being subjected to the necessity for reversal is set to 2 by the user's operation via the screen shown in FIG. 7D. ing. Therefore, the image forming system 100 does not set the papers P1 and P2, which are the two downstream sheets, for the plurality of sheets P1 to P5 to be subjected to the blank sheet cleaning, and the remaining sheets are 1 for the remaining sheets. Every other sheet is subject to the necessity of reversal. Therefore, the image forming system 100 sets the papers P3 and P5 as a target of the necessity for reversal. The sheets P1, P2, and P4 are not subjected to the necessity of reversal determination, and are subjected to blank sheet cleaning without being reversed.

<Inversion Necessity Determination Processing in Step S108>
FIG. 8 is a flowchart showing the procedure of the reversal necessity determination process shown in step S108 of FIG. The algorithm shown in the flowchart of FIG. 8 is stored as a program in the storage unit 112 of the main machine 110 and is executed by the control unit 111. The image forming system 100 sequentially applies this process to each sheet of paper determined as the target of the reversal necessity determination in the process of step S107. Hereinafter, a case where a jam occurs in the vicinity of the fixing unit 136 of the sub machine 130 and the blank sheet cleaning is performed using the paper remaining in the main machine 110 will be described as an example. It is assumed that the second surface of the sheet is a blank sheet on which no image is formed.

  As shown in FIG. 8, the image forming system 100 determines whether the coverage of one side of the sheet is equal to or smaller than a predetermined threshold (step S401). Specifically, the image forming system 100 confirms the printing state of the first surface of the paper and determines whether or not printing has been completed, and if printing has been completed, determines whether or not the coverage is equal to or less than a predetermined threshold. Check. The case where the first side of the sheet is not printed, that is, a blank sheet, is included when the coverage is equal to or less than a predetermined threshold. As described above, the coverage is the ratio of the area of the toner image to the area of the paper. For example, the coverage is acquired for each of CMYK four color toners and has a value in the range of 0 to 100%. As the threshold value for determining the coverage, for example, the total value of the coverage of each of the CMYK four color toners is set, and as a specific value, for example, 20% is set.

  When the coverage is equal to or smaller than the predetermined threshold (step S401: YES), the image forming system 100 determines that it is not necessary to reverse the paper. This is because even if the first side of the paper is blank or an image is formed, the coverage is below a predetermined threshold, so even if the paper is conveyed without being reversed, the first side of the discharged paper is This is because the execution result of blank paper cleaning can be appropriately determined.

  When the coverage is not equal to or less than the predetermined threshold (step S401: NO), the image forming system 100 determines that the sheet needs to be reversed. This is because a high coverage image is formed on the first surface of the paper, and when the paper is transported as it is, the execution result of the blank paper cleaning cannot be properly determined on the first surface of the discharged paper.

<Additional Blank Paper Cleaning Process in Step S111>
When the blank sheet cleaning process in step S110 is executed, the sheet used for the blank sheet cleaning is output to the paper discharge unit 165 of the post-processing device 160, for example. The paper used for blank paper cleaning is output to a separate separate tray so that it can be distinguished from normal printed matter and paper that has been pre-purged after printing. The user determines the remaining state of dirt in the image forming system 100 by checking the degree of dirt on the paper used for the blank paper cleaning, and judges the execution result of the blank paper cleaning. The user determines whether or not additional blank sheet cleaning needs to be performed according to the execution result of blank sheet cleaning.

  FIG. 9 is a flowchart showing the procedure of the additional blank sheet cleaning process shown in step S111 of FIG. FIG. 10 is a diagram showing an example of a screen displayed on the operation panel in the additional blank sheet cleaning execution confirmation process shown in step S501 of FIG. The algorithm shown in the flowchart of FIG. 9 is stored as a program in the storage unit 112 of the main machine 110 and is executed by the control unit 111.

  As shown in FIG. 9, the image forming system 100 confirms whether additional blank sheet cleaning is necessary (step S <b> 501). Specifically, the image forming system 100 displays a screen as shown in FIG. 10 on the operation panel 113 and confirms whether or not it is necessary to perform additional blank paper cleaning for the user. Further, the image forming system 100 accepts the setting of the number of sheets to be additionally blanked on the screen of FIG. In the example of FIG. 10, the number of additional blank paper cleanings is set to five. When the “Continue” button is pressed on the screen of FIG. 10, the image forming system 100 accepts an instruction to execute additional blank sheet cleaning together with the designation of the number of sheets. When the “Finish” button is pressed, the image forming system 100 receives an instruction not to execute additional blank sheet cleaning.

  Subsequently, the image forming system 100 determines whether or not an instruction to execute additional blank sheet cleaning is received in the process of step S501 (step S502).

  If an instruction to execute additional blank sheet cleaning has not been received (step S502: NO), the image forming system 100 ends the additional blank sheet cleaning process.

  When an instruction to execute additional blank sheet cleaning is received (step S502: YES), the image forming system 100 determines a sheet that is the target of reversal determination in the additional blank sheet cleaning process (step S503). Details of the process for determining the necessity of inversion will be described later.

  Subsequently, the image forming system 100 determines whether or not it is necessary to reverse the paper determined as the target of the reversal necessity determination in the process of step S503 (step S504). The reversal necessity determination process in step S504 is the same as the reversal necessity determination process in step S108 of FIG.

  Subsequently, the image forming system 100 determines whether or not the processing in step S504 is completed for each target sheet (step S505).

  If the processing has not been completed for all the target sheets (step S505: NO), the image forming system 100 returns to the processing of step S504 and performs the processing of step S504 until the processing is completed for all the sheets.

  When the processing is completed for all the target sheets (step S505: YES), the image forming system 100 conveys the sheet while inverting it as necessary, and performs additional blank sheet cleaning (step S506).

  When the additional blank sheet cleaning is completed, the image forming system 100 returns to the process of step S501, confirms whether further additional blank sheet cleaning is necessary, and repeats the processes of steps S501 to S506 until it is determined that the additional blank sheet cleaning is unnecessary. .

<Determination Processing for Reversal Necessity Determination Target at Step S503>
FIG. 11 is a flowchart illustrating the procedure of the process for determining the inversion necessity determination target shown in step S503 of FIG. The algorithm shown in the flowchart of FIG. 11 is stored as a program in the storage unit 112 of the main machine 110 and is executed by the control unit 111.

  As shown in FIG. 11, the image forming system 100 determines whether or not a sheet positioned on the most upstream side in the conveyance path among the sheets used in the blank sheet cleaning performed immediately before is the target of reversal determination. Is determined (step S601).

  When the most upstream sheet is the target of the necessity for reversal (step S601: YES), the image forming system 100 determines whether the most downstream sheet among the sheets used for the additional blank sheet cleaning is necessary for reversal. It is determined not to be the target of (step S602).

  If the most upstream sheet is not the target of reversal necessity determination (step S601: NO), the image forming system 100 determines the reversal necessity determination of the sheet located on the most downstream side among the sheets used in the additional blank sheet cleaning. The target is determined (step S603).

  Subsequently, the image forming system 100 determines the target of the reversal necessity determination for other sheets used in the additional blank sheet cleaning (step S604). Specifically, the image forming system 100 determines a target for determining whether or not to invert other sheets by a method similar to the process in step S107 of FIG. For example, in the image forming system 100, the most downstream sheet and other sheets are combined so that the sheet that is the object of the necessity for reversal appears every other sheet as shown in the example of FIG. 7B. The target of necessity determination may be determined.

  As described above, in the image forming system 100 according to the present embodiment, when at least one sheet remaining on the conveyance path is conveyed and blank paper cleaning is performed when a jam occurs, based on the printing state of at least one surface of the sheet, It is determined whether to reverse the paper. Thus, for example, both sides of the conveyance path can be cleaned with a surface in a printing state where it is easy to confirm the execution result of the blank sheet cleaning. Therefore, it is possible to appropriately determine the execution result of the blank paper cleaning.

  Further, the image forming system 100 determines whether the coverage of one side of the paper used for blank paper cleaning is higher than a predetermined threshold as the printing state, determines that the paper is to be reversed if it is high, and reverses if it is not high Judge not to let. Accordingly, since both sides of the conveyance path can be cleaned using a blank sheet or a surface with low coverage, the execution result of blank sheet cleaning can be determined more appropriately.

  Further, the image forming system 100 determines the printing state on one side of the paper used for blank paper cleaning, and the other side of the paper on which the printing state is not determined has a white paper or coverage equal to or less than a predetermined threshold. Therefore, it is possible to more reliably clean both sides of the conveyance path using a blank sheet or a surface with low coverage. Thereby, the execution result of the blank paper cleaning can be determined more reliably.

  Further, when performing blank sheet cleaning with a plurality of sheets, the image forming system 100 passes a portion of the blank sheet or a surface whose coverage is equal to or less than a predetermined threshold at least once toward the both sides of the conveyance path and targeted for blank sheet cleaning. In this way, the necessity of paper reversal is controlled. Accordingly, since both sides of the conveyance path can be cleaned at least once by the blank paper or the surface with low coverage, it is possible to reliably determine the execution result of the blank paper cleaning. Further, the cleaning effect is higher when the blank paper cleaning is performed on the paper surface having a low coverage (particularly, the blank paper surface) than on the paper surface having a high coverage. Therefore, both sides of the transport path can be effectively cleaned by controlling whether or not the sheet is reversed as described above.

  Also, as shown in the example of FIG. 7A, when performing blank paper cleaning with a plurality of papers, the image forming system 100 sets the paper located on the most upstream side in the transport path as a target of reversal determination. This paper is not reversed. Accordingly, it is possible to minimize the number of times the sheet is reversed while allowing the execution result of the blank sheet cleaning to be appropriately determined. Therefore, it is possible to suppress an increase in processing time and power consumption associated with paper reversal.

  Further, as shown in the example of FIG. 7B, when performing blank sheet cleaning with a plurality of sheets, the image forming system 100 determines whether or not every other sheet is reversed. Therefore, the both sides of the conveyance path can be alternately cleaned for each sheet with a surface on which it is easy to confirm the execution result of the blank sheet cleaning. As a result, it is possible to determine the execution result of the cleaning on both sides of the conveyance path every time two sheets of white paper are cleaned. For example, even when blank paper cleaning is interrupted halfway, the user can determine the execution result of the cleaning on both sides of the conveyance path by confirming the last two discharged sheets. Therefore, the execution result of the cleaning on both sides of the conveyance path can be determined early and reliably. Further, the cleaning effect is higher when the blank paper cleaning is performed on the paper surface having a low coverage (particularly, the blank paper surface) than on the paper surface having a high coverage. Therefore, it is possible to more evenly clean both sides of the transport path by determining whether or not it is necessary to reverse every other sheet as described above.

  In addition, when performing blank sheet cleaning with a plurality of sheets as in the example of FIG. 7C, the image forming system 100 does not invert a predetermined number of sheets positioned on the downstream side in the conveyance path, and the remaining number of sheets is not reversed. Every other sheet is subject to a determination of whether or not it is necessary to reverse it. Accordingly, the minimum number of sheets that are assumed to be necessary for completing the cleaning can be conveyed without being reversed, and every other sheet from which the cleaning is supposed to be completed can be determined as the target of reversal determination. . Accordingly, it is possible to reliably determine the execution result of the cleaning on both sides of the conveyance path while suppressing the number of times the sheet is reversed.

  In addition, when performing the additional blank paper cleaning, the image forming system 100, when the most upstream sheet conveyed in the immediately preceding blank sheet cleaning is the target of the reversal necessity determination, the most downstream side conveyed in the additional blank sheet cleaning. Do not flip the paper. In addition, when the most upstream sheet conveyed in the immediately preceding blank sheet cleaning is not the target of reversal necessity determination, the most downstream sheet conveyed in the additional blank sheet cleaning is determined as the reversal necessity determination target. Accordingly, the two sheets of the most upstream sheet for the immediately preceding blank sheet cleaning and the most downstream sheet for the additional blank sheet cleaning can be used to clean both sides of the conveyance path with a surface on which the execution result of the blank sheet cleaning can be easily confirmed. Therefore, when performing the additional blank sheet cleaning, the execution result of the previous blank sheet cleaning is inherited, whereby the execution result of the cleaning on both sides of the conveyance path can be reliably determined at an early stage.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims.

  For example, in the above embodiment, in the additional blank sheet cleaning execution confirmation process shown in step S501 of FIG. 9, the screen shown in FIG. 10 is displayed, and the execution instruction and the number of sheets to be executed are received. The instruction is not limited to this. For example, in addition to the above contents, an instruction regarding whether additional blank paper cleaning is required on the upper side or the lower side of the conveyance path may be received. Details will be described below.

  FIG. 12 is a diagram showing another example of a screen displayed on the operation panel in the additional blank sheet cleaning execution confirmation process shown in step S501 of FIG.

  The screen shown in FIG. 12 is provided with a check box for inputting the state of dirt attached to the paper discharged by the previous blank paper cleaning. “Upper side NG” corresponds to a state in which dirt is attached to the upper surface of the discharged paper. In this case, additional blank paper cleaning is required on the upper side of the conveyance path. “Lower side NG” corresponds to a state in which dirt is attached to the lower surface of the discharged paper. In this case, additional blank paper cleaning is required on the lower side of the conveyance path. The user confirms the degree of contamination of the paper discharged by the previous white paper cleaning, selects the corresponding check box, and then instructs execution of additional white paper cleaning. The image forming system 100 performs the processing in step S503 in FIG. 9 according to the check box selection status. For example, when the “upper side NG” check box is selected, the necessity of paper reversal may be controlled so that more execution results of blank paper cleaning on the upper side of the conveyance path can be confirmed. Alternatively, when both “upper side NG” and “lower side NG” are selected, the necessity of paper reversal may be controlled so that the execution result of blank paper cleaning on both sides of the conveyance path can be confirmed. According to such a configuration, when performing additional blank sheet cleaning, it is possible to appropriately determine whether or not to invert the sheet according to the execution result of the previous blank sheet cleaning, and to efficiently determine the execution result of the additional blank sheet cleaning. it can.

  In the above embodiment, the number of sheets to be subjected to additional blank paper cleaning is set by the user via the screen shown in FIG. However, it is not limited to this. For example, when performing additional blank sheet cleaning, the image forming system 100 may set the number of sheets per one to two in advance and perform additional blank sheet cleaning as a set of two sheets. At this time, one sheet of the set may not be reversed, and the remaining sheet may be a target of the necessity of reversal. Thereby, it is possible to reliably determine the execution result of the blank paper cleaning on both sides of the conveyance path by one additional blank paper cleaning. Also, it is possible to save the trouble of setting the number of sheets. Furthermore, since the execution result of blank paper cleaning on both sides of the conveyance path can be determined with a small number of sheets, it is possible to eliminate paper waste.

  In the above-described embodiment, an example in which blank paper cleaning is performed using paper remaining on the conveyance path of the image forming system 100 has been described. However, the present invention is not limited to this. When the number of sheets remaining on the conveyance path of the image forming system 100 is smaller than the number of sheets to be cleaned, the image forming system 100 conveys an insufficient number of new sheets from the sheet feeding tray or the sheet feeding device to blank sheets. Perform cleaning. At this time, the new sheet can be set so as not to be a target of the reversal necessity determination in the process of step S107 of FIG. 3 or the process of step S503 of FIG. Thereby, even when there is not enough remaining paper, the blank paper cleaning can be continued smoothly. Further, since the number of times of reversing the paper can be minimized, an increase in processing time and power consumption accompanying the reversal of the paper can be suppressed.

  Further, in the above-described embodiment, the execution result of the blank paper cleaning has been described as being determined by the user visually confirming the degree of contamination of the discharged paper. However, it is not limited to this. For example, the image reading device 150 reads an image on a sheet used for blank paper cleaning, and an image formed on the sheet based on a print job or the like is compared with a reading result in the control unit 111 of the main machine. The degree of contamination of the paper may be determined. As a result, the determination of the execution result of the blank paper cleaning can be automated, and the user workload can be reduced.

  In the above-described embodiment, the example in which the print state of the paper is acquired based on the coverage information acquired from the image forming unit 115 of the main machine 110 has been described. However, the print state acquisition method is not limited to this. For example, the print state of the paper may be estimated based on the print data included in the print job and the position of the paper, or the print state of the paper may be acquired based on the reading result by the line sensor or the like. .

  Further, in the above embodiment, when the main machine 110 uses a sheet with an image formed on the first surface (upper surface) in order to clean the periphery of the fixing unit 136 of the sub machine 130, the first sheet of the sheet is used. The example in which the necessity for reversal is determined based on the printing state of the surface has been mainly described. However, it is not limited to this. For example, the image forming system 100 may determine whether reversal is necessary based on the printing state of the second surface of the paper. Alternatively, the image forming system 100 confirms the printing state of both sides of the paper based on coverage information from the image forming unit, information on the print job, and the like, and determines whether reversal is necessary based on the printing state of both sides of the paper. Also good. For example, when performing blank paper cleaning using a plurality of sheets on which images are formed on both sides, the image forming system 100 adds the coverage of the surface facing the upper side of the conveyance path and the coverage of the surface facing the lower side. Whether or not the paper should be reversed may be determined so that the sum of the two is equal.

  In the above embodiment, the image forming system 100 is described as including the main machine 110, the first relay apparatus 120, the sub machine 130, the second relay apparatus 140, the image reading apparatus 150, and the post-processing apparatus 160. It is not limited to this. The image forming system 100 may include devices other than the above devices, or may not include some of the above devices.

  In the above embodiment, the case where the image forming system 100 is a serial tandem machine has been described as an example. However, the present invention is not limited to this. For example, the image forming system 100 may include three or more image forming apparatuses. The image forming system 100 may be any device as long as the image forming system 100 includes a mechanism capable of reversing the sheet upstream of a portion where blank paper cleaning is required.

  Further, in the above-described embodiment, each device constituting the image forming system 100 has been described as being provided separately, but the present invention is not limited to this. Each device may be configured as a single unit, or each device may be included in another device. Alternatively, each device may be further divided into a plurality of devices. For example, although the first relay device 120 has been described as having a reversing function and a discharging function, the first relay device 120 may be configured by being divided into two devices having respective functions.

  In the above-described embodiment, each treatment described as being executed by the control unit 111 of the main machine 110 may be executed by another device included in the image forming system 100. Alternatively, it may be executed by a server or a controller connected to the image forming system 100.

  In the above embodiment, the case where an image is formed on a sheet by the image forming system 100 and conveyed is described as an example. However, the recording material on which an image is formed and conveyed by the image forming system 100 is not limited to paper, and may be various recording materials made of resin, metal, or the like.

  In the above embodiment, the case where blank paper cleaning is required around the image forming unit and the fixing unit has been described. However, the present invention is not limited to this. The processing of the present embodiment can be applied even if it is determined that blank paper cleaning is necessary even outside the periphery of the image forming unit and the fixing unit.

  In the above-described embodiment, the example in which the image forming system 100 forms an image using toner by an electrophotographic method has been described, but the present invention is not limited to this. For example, the image forming system 100 may perform image formation using ink by an inkjet method.

  The means and method for performing various processes in the image forming system according to the above-described embodiments can be realized by either a dedicated hardware circuit or a programmed computer. The program may be provided by a computer-readable recording medium such as a flexible disk and a CD-ROM, or may be provided online via a network such as the Internet. In this case, the program recorded on the computer-readable recording medium is usually transferred to and stored in a storage unit such as a hard disk. The program may be provided as a single application software, or may be incorporated in the software of the apparatus as one function of the image forming system.

100 image forming system,
110 Main machine,
111 control unit,
112 storage unit,
113 operation panel,
114 paper transport section,
114a transport path,
115 Image forming unit,
116 fixing unit,
117 communication section,
120 relay device,
121 control unit,
122 storage unit,
123 paper transport section,
123a transport path,
124 reversing part,
125 paper discharge section,
126 communication unit,
130 sub machine,
131 control unit,
132 storage unit,
133 Operation panel,
134 paper transport section,
134a transport path,
135 Image forming unit,
136 fixing section,
137 communication unit,
140 relay device,
141 control unit,
142 storage unit,
143 paper transport section,
143a transport path,
144 Inversion part,
145 discharge section,
146 communications department,
150 image reading device,
151 control unit,
152 storage unit,
153 paper transport section,
153a transport path,
154 reading section,
155 communication department,
160 post-processing equipment,
161 control unit,
162 storage unit,
163 paper transport section,
163a transport path,
164 post-processing section,
165 paper discharge section,
166 Communication unit.

Claims (12)

A transport unit that transports the recording material along the transport path;
An image forming unit for forming an image on a recording material to be conveyed;
A fixing unit that heats and pressurizes the recording material on which the image is formed, and fixes the image to the recording material;
A reversing part capable of reversing the front and back of the recording material on the conveying path;
A determination unit that determines whether or not blank paper cleaning is required to perform cleaning by passing the recording material through the conveyance path when a recording material conveyance abnormality occurs;
When the blank paper cleaning is performed by transporting at least one recording material remaining in the transport path when the blank paper cleaning is necessary, the reversing unit is controlled based on the printing state of at least one side of the recording material. A control unit for determining whether to reverse the recording material;
An image forming system.   The control unit determines whether the coverage of one surface of the recording material used for the blank paper cleaning is higher than a predetermined threshold as the printing state, and determines that the recording material is reversed when it is higher, and is not high. The image forming system according to claim 1, wherein the image forming system is determined not to be reversed. The printing state is determined on one side of the recording material used for the blank paper cleaning,
3. The image forming system according to claim 1, wherein the other side of the recording material on which the printing state is not determined has a blank sheet or coverage equal to or less than a predetermined threshold value.   When the blank sheet cleaning is performed with a plurality of the recording materials, the control unit faces the both sides of the conveyance path facing the sheet surface at least once so that the surface of the blank sheet or the coverage is a predetermined threshold value or less. The image forming system according to claim 3, wherein the reversing unit is controlled so as to pass through a portion to be cleaned of the blank paper on the conveyance path.   The control unit determines whether to invert the recording material located on the most upstream side in the conveyance path when performing the blank paper cleaning with a plurality of the recording materials, and inverts the other recording materials. The image forming system according to claim 1, wherein the image forming system is not used.   5. The image according to claim 1, wherein when the blank sheet cleaning is performed with a plurality of the recording materials, the control unit determines whether or not the plurality of recording materials are reversed every other sheet. Forming system.   When the blank sheet cleaning is performed with a plurality of the recording materials, the control unit does not invert the predetermined number of recording materials positioned on the downstream side in the conveyance path, and every other recording material for the remaining recording materials. The image forming system according to claim 1, wherein it is determined whether or not to reverse the image.   When the control unit receives an instruction to additionally perform the second blank sheet cleaning after executing the first blank sheet cleaning with the predetermined number of the recording materials, the control unit is the most conveyed in the first blank sheet cleaning. When it is determined whether or not the recording material on the upstream side is to be reversed, the recording material on the most downstream side conveyed in the second blank paper cleaning is not reversed, and is conveyed in the first blank paper cleaning. And determining whether to invert the recording material on the most downstream side conveyed in the second blank sheet cleaning when it is not determined whether to invert the recording material on the most upstream side. The image forming system according to any one of 1 to 7.   When the control unit receives an instruction to additionally perform the second blank paper cleaning after performing the first blank paper cleaning with a predetermined number of the recording materials, the control unit conveys the two recording materials as a set. The image forming system according to claim 1, wherein it is determined whether one sheet of the set is not reversed and the remaining sheet is reversed.   When the control unit receives an instruction to additionally perform the second blank sheet cleaning after executing the first blank sheet cleaning with the predetermined number of recording materials, both sides of the conveyance path facing the sheet surface And determining whether to invert the recording material in consideration of the instruction when performing the second blank paper cleaning. The image forming system according to any one of 1 to 9.   When the blank sheet cleaning is performed, if the recording material does not remain in the transport path, the control unit transports a new recording material and executes the blank sheet cleaning. The image forming system according to claim 1, wherein the image forming system does not determine whether to reverse the recording material. A conveying unit that conveys the recording material along a conveying path; an image forming unit that forms an image on the conveyed recording material; and heating and pressurizing the recording material on which the image is formed, and A method executed in an image forming system having a fixing unit for fixing the recording material and a reversing unit capable of reversing the front and back of the recording material on the conveyance path,
A determination step of determining whether or not blank paper cleaning is required to perform cleaning by passing the recording material through the conveyance path when a recording material conveyance abnormality occurs;
When the blank paper cleaning is performed by transporting at least one recording material remaining in the transport path when the blank paper cleaning is necessary, the reversing unit is controlled based on the printing state of at least one side of the recording material. A control step for determining whether to reverse the recording material;
An image forming method comprising: