JP2013054147A - Image forming system and printing control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress deterioration of productivity caused by executing an adjustment mode.SOLUTION: An image forming system comprises: a first image forming apparatus 101; and a second image forming apparatus 102 connected downstream thereof, and forms, when executing a double-sided print job, an image on a first surface of a recording material in the first image forming apparatus and an image on a second surface of the recording material in the second image forming apparatus after reversing the surface of the recording material. When the print job is interrupted in one of the first image forming apparatus and the second image forming apparatus and an adjustment operation for image formation is performed and if the other image forming apparatus has another adjustment operation for image formation executed before the print job is finished, the print job in the other image forming apparatus is interrupted, and a timing for executing the adjustment operation is controlled so that respective adjustment operations in the one image forming apparatus and in the other image forming apparatus are executed in parallel (S301-S307).

Description

  The present invention relates to an image forming system that forms an image by connecting a plurality of image forming apparatuses, and a print control apparatus that controls the image forming system.

  In recent years, image forming apparatuses such as copiers, printers, and multifunction machines have been required to have higher speed. In view of this, an image forming system has been proposed that forms an image by providing a relay unit for conveying a recording material between two image forming apparatuses.

  This type of image forming system has a configuration in which a plurality of image forming apparatuses having image forming functions of charging, exposure, development, transfer, and fixing are connected. The upstream image forming apparatus forms an image on the first surface of the recording material, and then reverses the recording material by a relay unit, and the downstream image forming apparatus forms an image on the second surface of the recording material. Do. As a result, the number of output pages for double-sided printing can be substantially doubled compared to the number of output pages for a single conventional image forming apparatus, and the speed can be increased. Such a connected image forming system connects two image forming apparatuses that are used as image forming apparatuses in series through a relay unit without using a new hardware design. It can be commercialized as a coupled image forming apparatus. For example, in Patent Document 1, two laser beam printer products are connected in series with a reversing unit interposed therebetween, and each product prints the front and back surfaces, thereby performing double-sided printing. An image forming apparatus has been proposed.

  In the image forming apparatus, the image density of the toner image may change due to aging of the photoconductor and the developing device, environmental temperature and humidity in which the apparatus is installed, or the like. Therefore, many techniques for stabilizing the image density by adjusting parameter factors that affect the image density of the toner image, such as a charging voltage and a developing voltage, at appropriate timings have been proposed. However, in the conventional image forming apparatus, even if the print job is not so large, if the cumulative count value of the number of printed sheets reaches a predetermined threshold during printing, the print job is temporarily stopped and density adjustment is performed. Will enter the adjustment mode. As a result, the time required from the start of printing to the end of printing may take longer than expected. Therefore, for example, in Patent Document 2, in the case of a print job in which the number of printed sheets is not very large, image formation is performed such that the adjustment mode is not entered in the middle of the print job as much as possible, and the adjustment mode is entered at an appropriate timing to execute density adjustment or the like. A device has been proposed.

JP-A-6-343125 JP 2004-142250 A

  However, when the adjustment mode is executed in the above-described coupled image forming apparatus, there are the following problems. That is, even in the connection type image forming apparatus, even when the print job is a single-sided print or a double-sided print job, the front and back side print rates may be different. In such a case, there is a possibility that the upstream and downstream image forming apparatuses may enter the adjustment mode at different timings due to differences in the cumulative count value of the number of printed sheets in each image forming apparatus. In particular, in the connection type image forming apparatus, the frequency of entering the adjustment mode is higher than in the case of one image forming apparatus, and as a result, the productivity decreases. Further, in the connection type image forming apparatus, even if the upstream image forming apparatus is capable of image formation, if the downstream image forming apparatus needs to be adjusted, both image forming operations are performed until the adjustment is completed. Both devices are forced to interrupt the execution of a print job. As described above, in the connection type image forming apparatus, there is a high possibility that an extra waiting time for the print job will occur as compared with the case of one image forming apparatus.

  The present invention has been made under such circumstances, and an object thereof is to suppress a decrease in productivity due to execution of an adjustment mode.

  In order to solve the above-described problems, the present invention has the following configuration.

  (1) When a first image forming apparatus and a second image forming apparatus are connected to the downstream side of the first image forming apparatus and a double-sided printing job is executed, an image is printed on the first surface of the recording material by the first image forming apparatus. In the image forming system for forming and forming an image on the second surface of the recording material with the second image forming apparatus by reversing the front and back of the recording material, the first image forming apparatus and the second image When an image forming adjustment operation is executed by interrupting a print job in one of the image forming apparatuses, another image forming adjustment executed before the end of the print job in the other image forming apparatus If there is an operation, the print job in the other image forming apparatus is interrupted, and the adjustment operation is performed so that the adjustment operation in the one image forming apparatus and the adjustment operation in the other image forming apparatus are executed in parallel. Execution Image forming system comprising a control means for controlling the timing.

  (2) When the first image forming apparatus and the second image forming apparatus are connected to the downstream side of the first image forming apparatus and the double-sided printing job is executed, the first image forming apparatus performs an image onto the first surface of the recording material. In the printing control apparatus, the first image forming apparatus and the second image are formed, and the second image forming apparatus forms an image on the second surface of the recording material by reversing the front and back of the recording material. When an image forming adjustment operation is executed by interrupting a print job in one of the image forming apparatuses, another image forming adjustment executed before the end of the print job in the other image forming apparatus If there is an operation, the print job in the other image forming apparatus is interrupted, and the adjustment operation is performed so that the adjustment operation in the one image forming apparatus and the adjustment operation in the other image forming apparatus are executed in parallel. Execution Printing control apparatus provided with a control means for controlling the timing.

  According to the present invention, it is possible to suppress a decrease in productivity due to execution of the adjustment mode.

1 is a diagram illustrating a configuration of an image forming unit and a relay unit of an image forming system in the present embodiment. Schematic showing the system configuration of the image forming system of the present embodiment The figure explaining the density | concentration detection sensor in this embodiment, and a resist detection sensor Flowchart showing the procedure of the adjustment mode in the present embodiment The figure explaining the table which shows the reservation of the print job in this embodiment, and the management table of an adjustment item The figure explaining the management table of the adjustment item in this embodiment The flowchart which shows the process sequence at the time of execution of adjustment A in this embodiment. The flowchart which shows the process sequence at the time of execution of the adjustment 1 in this embodiment. The flowchart which shows the process sequence at the time of execution of adjustment B in this embodiment. The figure which shows the management table of the adjustment item in this embodiment, and the reservation table of a print job

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<Linked image forming apparatus>
FIG. 1A is a schematic configuration diagram illustrating only an image forming unit of a coupled image forming apparatus (hereinafter referred to as an image forming system) of the present embodiment. 1A includes a first image forming apparatus 101 (first image forming apparatus) and a second image forming apparatus 102 (second image forming apparatus) connected by a relay unit 201. The configuration functions as an image forming apparatus. Note that the first image forming apparatus 101 and the second image forming apparatus 102 are the same image forming apparatus, and each has a configuration that functions as an image forming apparatus alone, and is given a different symbol for distinction. Since a single device functions as an image forming apparatus, designing one type of image forming apparatus has an advantage that it can be used for both a single image forming apparatus and a connected image forming apparatus.

  The image forming system shown in FIG. 1A is a monochrome (for example, black and white) image forming apparatus, and this image forming unit will be described below. The photosensitive drum 1-1 as an image carrier of the first image forming apparatus 101 rotates in the direction of the arrow and is uniformly and uniformly charged to a predetermined potential by a charging wire 2-1 to which a voltage is applied. In the case of the copy function, the exposure device 3-1 irradiates the photosensitive drum 1-1 with an exposure light beam such as a laser beam in accordance with the original image read by the scanner 8-1 as an image reading device. In the case of a print function or FAX function, image information transmitted from a personal computer (not shown) connected to the LAN (hereinafter referred to as a PC) or the like is received by the controller 9-1 that is an image receiving apparatus. Then, the exposure device 3-1 irradiates the photosensitive drum 1-1 with an exposure beam according to the received image. An electrostatic latent image is formed by reducing the potential at the portion irradiated with the exposure light beam on the photosensitive drum 1-1, and a toner image is formed on the photosensitive drum 1-1 by the toner of the developing device 4-1. Is done.

  Here, the recording material Q taken out from the paper feeding cassettes 20-1, 21-1, and 22-1 serving as a paper feeding unit of the first image forming apparatus 101 is transferred from the path A to the photosensitive drum 1-1 and the transfer roller 5. The toner image on the photosensitive drum 1-1 is conveyed to the transfer nip portion with -1 in time. The toner image on the photosensitive drum 1-1 is transferred to the first surface of the recording material Q by the transfer roller 5-1 to which voltage is applied. The surface of the recording material Q onto which the toner image has been transferred by the first image forming apparatus is defined as the first surface. Toner remaining on the photosensitive drum 1 without being transferred to the recording material Q (hereinafter referred to as “transfer residual toner”) is collected by a photosensitive drum cleaning device 6-1 in which a blade or a brush is disposed. The photosensitive drum 1-1 from which the transfer residual toner has been removed is uniformly charged again by the charging wire 2-1, and repeatedly used for image formation. The recording material Q onto which the toner image has been transferred is conveyed to the fixing device 7-1 and is heated and pressurized to fix the toner image. Thereafter, the recording material Q is delivered from the path B to the relay unit 201 on the downstream side in the recording material conveyance direction. The relay unit 201 switches back and forth the recording material Q by switching back the recording material Q in the order of the path C and the path D. As a result, the recording material Q is reversed.

  The image forming unit of the second image forming apparatus 102 has the same configuration as that of the first image forming apparatus 101, and the path E is transferred to the transfer nip portion between the photosensitive drum 1-2 and the transfer roller 5-2 by the above-described image forming procedure. Thus, the recording material Q is conveyed, and the toner image is transferred to the recording material. The surface of the recording material Q onto which the toner image has been transferred by the second image forming apparatus 102 is defined as the second surface. The recording material Q carrying the toner image is conveyed to the fixing device 7-2, receives heat and pressure, the toner image is fixed on the second surface of the recording material Q, and is discharged from the path F to the outside of the apparatus. . Note that the second image forming apparatus 102 also includes sheet feeding cassettes 20-2, 21-2, and 22-2 that are sheet feeding units, like the first image forming apparatus 101.

  Further, in order to perform double-sided printing, the first image forming apparatus 101 and the second image forming apparatus 102 are switched back after the recording material Q that has been printed on one side passes through the fixing device, and the printing surface is reversed. And a reverse conveying unit that conveys the image to the image forming unit. The reverse transfer unit of the first image forming apparatus serving as the first reverse transport unit is disposed below the transfer roller 5-1, and the reverse transfer unit of the second image forming apparatus serving as the second reverse transport unit is configured to transfer the transfer roller 5. -2 is provided at the bottom.

<Relay unit>
The image forming system shown in FIG. 1A is configured to reverse the recording material Q by switching back the recording material Q in the relay unit 201. By the way, it takes time to switch back the recording material Q. Therefore, when the recording material conveyance speed of the first image forming apparatus 101 and the second image forming apparatus 102 is, for example, 300 mm / second, the recording material conveyance speed of the relay unit 201 is increased to, for example, 1000 mm / second. Therefore, it is possible to prevent a decrease in productivity due to switchback. In this case, at the entrance of the relay unit 201, the conveyance speed of the recording material is increased from 300 mm / second in the first image forming apparatus 101 to 1000 mm / second, and the interval with the subsequent recording material is widened. The recording material Q is switched back. Then, after the recording material Q is switched back, at the outlet of the relay unit 201, the recording material conveyance speed is reduced from 1000 mm / second to 300 mm / second, which is the conveyance speed in the second image forming apparatus 102, thereby switching back. Can prevent the productivity drop.

  The relay unit may employ an inversion method other than switchback, such as the relay unit 202 shown in FIG. The relay unit 202 in FIG. 1B holds the recording material Q in a direction perpendicular to the conveyance direction of the recording material Q while maintaining the traveling direction of the recording material Q conveyed from the first image forming apparatus 101 through the path B. Rotate G (180 degrees clockwise or 180 degrees counterclockwise). Accordingly, the relay unit 202 reverses the front and back surfaces of the recording material Q, and conveys the recording material Q from the path E to the second image forming apparatus 102. Since the relay unit 202 can accurately match the image writing positions of the leading ends of the first surface and the second surface of the recording material, it is more suitable when image position accuracy is required. Further, when the image forming apparatus has a switchback function, the relay unit 201 may be configured not to reverse the recording material Q. In this case, after passing through the fixing device 7-1, the first image forming apparatus 101 switches back the recording material Q and conveys the recording material P to the relay unit 201 through the path B. Then, the relay unit 201 conveys the recording material Q to the second image forming apparatus 102 as it is without reversing the recording material Q.

<Color image forming unit>
The image forming system in FIG. 1A has a configuration in which two single-color image forming apparatuses are connected, but may have a configuration in which two color image forming apparatuses are connected. FIG. 1C shows an image forming unit of a tandem color image forming apparatus applied to the image forming system. In the image forming unit shown in FIG. 1C, four image forming units Y (yellow), M (magenta), C (cyan), and Bk (black) that form toner images of different colors are arranged. The An intermediate transfer belt 10 as an intermediate transfer member is disposed so as to pass through these image forming units. Note that the image forming unit in FIG. 1C is commonly used in two connected image forming apparatuses. In FIG. 1A, two image forming apparatuses are distinguished by using a hyphen (for example, like the photosensitive drum 1-1 and the photosensitive drum 1-2). In the following description, the first image forming apparatus is used. Components common to 101 and the second image forming apparatus 102 are omitted from the reference numerals following the hyphen. That is, for example, the photosensitive drum 1 refers to both the photosensitive drum 1-1 of the first image forming apparatus 101 and the photosensitive drum 1-2 of the second image forming apparatus 102. Further, the four image forming units Y, M, C, and Bk used by the color image forming unit have the same configuration. Hereinafter, the configuration of the yellow image forming unit Y will be described as a representative. For the other image forming units, members having the same configuration and function as those of the yellow image forming unit Y are denoted by the same reference numerals, and only the subscripts Y, M, C, and Bk indicating the respective units are changed.

  As an image carrier, for example, a cylindrical electrophotographic photosensitive member (hereinafter referred to as “photosensitive drum”) 1Y whose surface layer is made of OPC (organic optical semiconductor) is rotationally driven in the direction of an arrow. A charging wire (charging roller) 2Y for uniformly and uniformly charging the surface of the photosensitive drum 1Y rotates in contact with the photosensitive drum 1Y after a predetermined voltage is applied, and charges the surface of the photosensitive drum 1Y to a predetermined potential. To do. The charged photosensitive drum 1Y is exposed to exposure light (laser light or the like) by the exposure device 3Y, and an electrostatic latent image corresponding to the color separation image of the input document is formed. The developing device 4Y develops the electrostatic latent image using toner charged by the developing roller, and a toner image corresponding to the electrostatic latent image is formed on the surface of the photosensitive drum 1Y. The toner image on the photosensitive drum 1Y is transferred at the primary transfer nip portion T1Y between the photosensitive drum 1Y and the primary transfer roller 5Y by the primary transfer roller 5Y at an approximately same speed as the peripheral speed of the photosensitive drum 1Y. 10 is transferred. Hereinafter, transfer of the toner image from the photosensitive drum 1Y to the intermediate transfer belt 10 is referred to as primary transfer. The toner remaining on the photosensitive drum 1Y after the primary transfer is collected by a blade or brush of the photosensitive drum cleaning device 6Y. The photosensitive drum 1Y from which the residual toner after the primary transfer has been removed is uniformly and uniformly charged again by the charging wire (charging roller) 2Y, and is repeatedly used for image formation.

  The intermediate transfer belt 10 is stretched around a support roller 11, a drive roller 12, and a backup roller 13. The intermediate transfer belt 10 is rotationally driven by the rotation of the driving roller 12 in the direction of the arrow while contacting the photosensitive drums 1Y, 1M, 1C, and 1Bk of the four image forming units Y, M, C, and Bk. When the full color mode (full color image formation) is selected, the above-described image forming operation is executed by the four image forming units Y, M, C, and Bk. Then, the yellow toner image, the magenta toner image, the cyan toner image, and the black toner image respectively formed on the photosensitive drums 1Y, 1M, 1C, and 1Bk are sequentially multiplex-transferred onto the intermediate transfer belt 10. The four color toner images transferred onto the intermediate transfer belt 10 are transferred onto the recording material Q by the secondary transfer roller 14 at the secondary transfer nip T2 between the backup roller 13 and the secondary transfer roller 14. Is done. Hereinafter, transfer of the toner image from the intermediate transfer belt 10 to the recording material Q is referred to as secondary transfer.

  The recording material Q is fed from one of the paper feed cassettes 20-1, 21-1, 22-1 of the first image forming apparatus 101, and is transferred to a secondary transfer nip portion by a registration roller pair (not shown). At T2, the sheet is conveyed at a predetermined control timing according to the toner image on the intermediate transfer belt 10. The recording material Q to which the toner image has been transferred is conveyed to the fixing device 7, and the toner image on the recording material Q is pressurized and heated to fix the toner image on the recording material Q. The toner remaining on the intermediate transfer belt 10 after the secondary transfer is collected by a blade or a brush of the intermediate transfer cleaning device 15. Then, the intermediate transfer belt 10 from which the residual toner after the secondary transfer is removed is repeatedly subjected to primary transfer.

  In the color image forming unit shown in FIG. 1C, for example, in the case of black monochromatic image formation or 2-3 color mode, image formation on the photosensitive drum 1 is executed in the image forming unit of the necessary color. Is done. At this time, in the unnecessary color image forming unit, the photosensitive drum 1 is not in contact with the intermediate transfer belt 10 and is idling. The toner image on the photosensitive drum 1 is primarily transferred onto the intermediate transfer belt 10 at the primary transfer nip T1. Thereafter, the toner image primarily transferred onto the intermediate transfer belt 10 is secondarily transferred to the recording material Q at the secondary transfer nip T2, and the recording material Q onto which the toner image has been transferred is conveyed to the fixing device 7. The

<System configuration of image forming system>
FIG. 2 is a schematic diagram showing a system configuration of the image forming system of the present embodiment. The image forming system illustrated in FIG. 2 includes a sheet feeding unit 401 having a sheet feeding deck capable of feeding a large capacity recording material on the upstream side of the first image forming apparatus 101 in the recording material conveyance direction. Further, a finisher unit 501 is provided on the downstream side of the second image forming apparatus 102 in the recording material conveyance direction to perform cutting processing, bookbinding processing, and the like of the recording material after image formation. Since the components of the first image forming apparatus 101 and the second image forming apparatus 102 are the same, in FIG. 2, hyphens are used for the reference numerals of the components (for example, like CPU 30-1 and CPU 30-2). The components of the two image forming apparatuses are distinguished. In the following description, when the reference numeral with a hyphen is not used, for example, the CPU 30 is a CPU 30-1 that is a first control unit of the first image forming apparatus 101 and a second one of the second image forming apparatus 102. Both of the CPUs 30-2 that are the control means are indicated.

  Each image forming apparatus includes a control unit, a density detection sensor 31, a registration detection sensor 32, an operation display unit 40, and the image forming unit described above. Further, the control unit includes a CPU 30 that controls the image forming unit and each sensor, a ROM 33, a RAM 34, and an EEPROM 35. The ROM 33 stores an arithmetic program executed by the CPU 30 and the like. The RAM 34 temporarily stores control data and calculation results for controlling the image forming apparatus. The EEPROM 35 is a kind of nonvolatile memory and is a ROM whose contents can be rewritten. In the EEPROM 35, as will be described later, each adjustment item such as density adjustment and registration adjustment stores the number of printed pages from the previous adjustment to the next adjustment as a threshold, or prints from the previous adjustment to the present. This is used to store the number of pages for each adjustment item. Furthermore, the EEPROM 35 also stores development voltage values for density adjustment, adjustment values for various sensors, and the like.

  The operation display unit 40 is connected to the CPU 30 and is used for displaying various information, setting the number of prints from the user, printing instructions, and the like. Further, signals can be exchanged between the control units of the first image forming apparatus 101 and the second image forming apparatus 102. The sheet feeding unit 401 is controlled by the CPU 30-1 of the first image forming apparatus 101, and the finisher unit 501 is controlled by the CPU 30-2 of the second image forming apparatus 102. Details of the density detection sensor 31 and the registration detection sensor 32 will be described later.

<Various adjustment processes in the image forming apparatus>
Next, various adjustment processes in the electrophotographic image forming apparatus will be described.

(1) Density Adjustment Processing Generally, in an electrophotographic image forming apparatus, if the image density fluctuates due to various conditions such as changes in the usage environment and the number of prints, the original correct color tone cannot be obtained. In the present embodiment, a density detection toner image P (patch P) is created on the intermediate transfer belt 10 with each color toner, the density of the patch P is detected by the density detection sensor 31, and the detection result is used as the development voltage. The image density is controlled by feeding back to the set value.

  FIG. 3A is a schematic diagram showing the configuration of the density detection sensor 31. As shown in FIG. 3A, the density detection sensor 31 includes a light emitting element such as an LED, a light receiving element such as a photodiode, and a holder. The density of the patch P is measured by irradiating the patch P on the intermediate transfer belt 10 with infrared light from the light emitting element and measuring the reflected light from the patch P with the light receiving element.

  FIG. 3B is a diagram illustrating a state in which the density of the patch P formed on the intermediate transfer belt 10 is detected by the density detection sensor 31. In the actual density detection of the patch P, a vertical (L = 14 mm) × horizontal (L = 14 mm) square pattern is used as the patch P pattern, and this patch pattern is a half that has been subjected to a specific dither process. It is a tone pattern. Assuming that the exposure amount when the entire surface exposure is performed is 100%, the patch pattern employed in the present embodiment is a pattern having an exposure amount of about 60%.

  A plurality of patch patterns are formed on the intermediate transfer belt 10 while changing the development voltage with a constant voltage width, and the density of these patch patterns is detected by the density detection sensor 31. Based on the obtained detection value, a development voltage value is calculated so that the patch pattern has a predetermined density. Then, a development voltage value is calculated for each color of the toner, and the calculated development voltage value is used at the time of image formation. Such control is called development voltage control.

  In addition, the development voltage value is fixed to the calculated value, and multiple patch patterns are created and density detection is performed while changing the tone (exposure amount) of the halftone pattern to which specific dither processing has been applied at regular intervals. The sensor 31 may detect the density of the patch pattern. Further, based on these detection values, control may be performed to correct the exposure amount when performing dither processing so that smooth gradation can be obtained. This control is called halftone control. Note that the density of the patch pattern is calculated from the difference between the light reception value of the reflected light only on the background of the intermediate transfer belt 10 performed prior to the execution of the image density control and the light reception value of the reflected light through the patch pattern. The

  It is desirable that the image density control be performed when the power is turned on, when a consumable such as a toner cartridge is replaced, or after a predetermined number of image formations have been completed since the previous execution of the image density control. It should be noted that the image density control can be performed at a timing desired by the user by an adjustment instruction from the operation display unit 40 or the like, and may be executed in accordance with a control procedure of a flowchart described later.

(2) Registration Adjustment Processing In the registration adjustment processing, as shown in FIG. 3C, a registration detection sensor 32 disposed at the opposing portion of the intermediate transfer belt 10 in the image forming apparatus main body is used. The image forming unit of the color image forming apparatus of this embodiment reproduces a color image by transferring four color toner images on a recording material for each color and mixing the colors at the time of fixing. Therefore, when transferring the toner image onto the recording material, if the correct color overlap is impaired, the original correct color tone cannot be obtained. In this embodiment, a registration detection toner image (line) is created with each color toner on the intermediate transfer belt 10, and the result of detecting the transfer position by the registration detection sensor 32 is the electrostatic latent image formation start timing. The resist control is performed by feeding back to the above.

  FIG. 3C is a schematic diagram showing the configuration of the registration detection sensor 32. As shown in FIG. 3C, the resist detection sensor 32 includes a light emitting element such as an LED, a light receiving element such as a photodiode, and a holder, and an optical density detection sensor similar to the density detection sensor 31. It is possible to use. Here, in the resist control, the transfer position is detected from the intensity change of the amount of received light when the resist detection toner image (line) passes through the resist detection sensor 32, and based on this, the electrostatic force due to laser scanning / exposure is detected. Temporal correction is performed on the start timing of latent image formation.

  The registration control is preferably performed when the power is turned on, when the consumables such as the toner cartridge and the intermediate transfer belt 10 are replaced, after a predetermined number of images have been formed after the previous registration control is executed. It is also possible to perform registration control at a timing desired by the user by a registration adjustment instruction from the operation display unit 40 by the user.

(3) Charging Wire Adjustment Processing The charging wire adjustment processing is performed by using a charging wire cleaning member for the charging wire 2 in the image forming apparatus main body. In the image forming apparatus of the present embodiment, a high voltage is applied to the charging wire 2 to uniformly charge the photosensitive drum 1 and ensure an appropriate development contrast. For this reason, when the photosensitive drum 1 is not uniformly charged, local density unevenness, deterioration of fogging, and the like occur, and the original good image quality cannot be maintained. Therefore, in this embodiment, the charging wire 2 is periodically cleaned by the charging wire cleaning member to remove dust and scattered toner in the air attached to the charging wire by a high voltage, and the photosensitive drum 1 is uniformly charged. To be. During the charging wire adjustment process, the photosensitive drum 1 and the developing device 4 do not need to be driven and are stopped. In the primary transfer nip T1, it is not necessary to bring the photosensitive drum 1 and the intermediate transfer belt 10 into contact with each other, so only the intermediate transfer belt 10 can be driven independently, and the recording material Q is conveyed even during the main adjustment. It is possible.

  Also, the timing of wire cleaning is desirable when the power is turned on, when consumables such as the toner cartridge and the intermediate transfer belt 10 are replaced, or after the predetermined number of images have been formed after the previous registration control is executed. . It is also possible to carry out charging wire adjustment at a timing desired by the user by an adjustment instruction from the operation display unit 40 by the user.

<Adjustment Processing Sequence for One Image Forming Apparatus>
First, in the present embodiment, a control sequence of adjustment processing when either the first image forming apparatus 101 or the second image forming apparatus 102 performs image formation alone will be described with reference to the flowchart of FIG. The process shown in FIG. 4 is executed by the CPU 30 based on a control program stored in the ROM 33 in the control unit. Similarly, the processing of the flowchart in the present embodiment thereafter is executed by the CPU 30.

  First, in step 101 (hereinafter referred to as S101), the CPU 30 determines whether or not the currently executed job (print job) has ended. If the job has not ended, the process of S101 is repeated. When the job ends, the process proceeds to S102. In S102, the CPU 30 determines whether or not the next print job is reserved from the print job reservation table of FIG. 5A to be described later. If is entered, the process proceeds to S103.

  In S103, the CPU 30 analyzes the contents of the print job to be executed next from the print job reservation table shown in FIG. FIG. 5A shows an example of a print job reservation table. The left column indicates the print job reservation number, the right column indicates the print job status (in execution), and the print job contents. Indicates. In FIG. 5A, job 1 is the most recently executed print job, job 2 scheduled to be executed next is a job for printing 70 copies (one copy is composed of 10 pages), and job 3 is 50. This is a job for printing one copy (one copy consists of 10 pages). In S103, the CPU 30 calculates the total number of print pages (10 pages / copy × 70 copies = 700 pages) of the job 2 scheduled to be executed next from the reservation table of FIG.

  In S104, the CPU 30 determines whether there is an adjustment item that enters the adjustment mode during execution of the next print job. This determination is made as follows. For the corresponding adjustment item, X is the number of print pages (threshold) from the end of the previous adjustment until the next adjustment is performed, and Y is the number of print pages (adjustment count value) from the end of the previous adjustment to the present. Then, the number of remaining print pages until the next adjustment is represented by (XY). Parameters such as the threshold value X and the adjustment count value Y are stored in the EEPROM 35 and saved. If the total number of print pages in the next print job to be executed is Z, and the following conditional expression (Formula 1) is satisfied, the timing of the adjustment operation executed during the next print job can be changed. The number of adjustments performed during the print job can be reduced.

Z mod X> (XY) (Formula 1)
In (Expression 1), “Z mod X” on the left side indicates the remainder when the total number of printed pages (Z) is divided by the threshold (X), and means the number of printed pages after the adjustment items are performed. The fact that the conditional expression of (Expression 1) is satisfied is that the number of print pages after the adjustment item is executed is larger than the number of remaining print pages until the next adjustment, so during the execution of the next print job, At least once, this means entering the adjustment mode in order to carry out the adjustment items.

  FIG. 5B is an example of a table for managing the execution timing of the adjustment items provided in the EEPROM 35. For each adjustment item (in FIG. 5B, only one item “adjustment item 1” is displayed. ) Threshold X, adjustment count value Y, number of remaining print pages, and the like. The adjustment items are not limited to the above-described density adjustment, resist adjustment, and charging wire adjustment because there are adjustment items specific to each image forming apparatus. In the table shown in FIG. 5B, the threshold value X is 500 pages, and a unique value is set for each image forming apparatus, and the user can change the threshold value via the operation display unit 40. Since the number of print pages (adjustment count value) Y from the end of the previous adjustment to the present is 450 pages, the remaining number of print pages (XY) until entering the next adjustment mode is 50 pages (= 500-450). It becomes. The total print page number Z of the print job to be executed next is 700 pages corresponding to job 2 of the reserved job shown in FIG. Therefore, when job 2 is executed, the first adjustment operation of adjustment item 1 is executed when printing of 50 pages is completed.

  When 500 pages have been printed after the adjustment work is completed, the condition of the threshold value X of adjustment item 1 is satisfied, so the second adjustment work is executed. That is, the adjustment item 1 is executed twice while the job 2 is being executed. However, when the conditional expression (Formula 1) is satisfied, it is determined that the adjustment work for the adjustment item 1 needs to be performed at least once during execution of the job 2 before the job 2 is executed. it can. Therefore, by adjusting the adjustment item 1 before executing the job 2, the adjustment item 1 is adjusted once when printing of 500 pages is completed during the job 2. As a result, the number of adjustment modes in the print job can be reduced. Therefore, it can be seen that the number of executions of the adjustment items in the print job to be executed next can be reduced depending on whether or not (Equation 1) is satisfied.

  In S <b> 104, the CPU 30 determines whether or not the next print job satisfies (Equation 1) in order to determine whether or not there is an adjustment item that enters the adjustment mode during execution of the next print job. The CPU 30 ends the process if (Equation 1) is not satisfied, and proceeds to S105 if (Equation 1) is satisfied. In S105, the CPU 30 executes the adjustment mode in order to execute the corresponding adjustment item. In S106, the CPU 30 determines whether or not the execution of the adjustment mode has been completed. If it has not been completed, the process of S106 is repeated. If it has been completed, the process proceeds to S107. In S107, the CPU 30 clears the adjustment count value Y indicating the number of printed pages from the end of the previous adjustment to the present, and ends this process.

  In general, operations between operators such as removing a bundle of recording materials discharged to the stack tray or booklet tray of the finisher unit 501 and supplying recording materials for the next print job are performed between print jobs. Done. Therefore, by performing in advance the adjustment items that are expected to enter the adjustment mode during the next print job between the print jobs that are operated by the operator, the downtime during the job execution is reduced. The number of adjustments performed during a job can be reduced.

<Adjustment processing sequence in image forming system>
Next, the cooperation processing of the two image forming apparatuses when the adjustment process is performed in the image forming system including the two image forming apparatuses will be described. In the following description, it is assumed that the print job is duplex printing. As described with reference to FIG. 2, the image forming system starts from the sheet feeding unit 401, the first image forming apparatus 101, the relay unit 201, the second image forming apparatus 102, and the finisher unit 501 in order from the upstream in the recording material conveyance direction. It is configured. When the print job is duplex printing, in the image forming system, the first image forming apparatus 101 and the second image forming apparatus 102 form an image on each side, so that the image forming system has a substantially double speed compared to a single image forming apparatus. Can be output.

(1) Adjustment Process in Image Forming System The adjustment process in each image forming apparatus is as described above. However, if each adjustment process is performed independently (asynchronously) in each image forming apparatus, one print job The adjustment will be performed twice or more. As a result, there has been a problem that productivity is lowered during the adjustment process, or image formation is stopped depending on circumstances.

  Adjustment processing that affects productivity can be roughly classified into three types according to the degree of influence on image formation. The first adjustment processing is adjustment processing in the first image forming apparatus 101 (hereinafter referred to as adjustment 1), and the second adjustment processing is impossible for the recording material conveyance in the second image forming apparatus 102. The adjustment items are density adjustment and registration adjustment (hereinafter referred to as adjustment A). The third adjustment processing is charging wire adjustment (hereinafter referred to as adjustment B), which is an adjustment item that enables the recording material conveyance in the second image forming apparatus 102.

  When adjustment 1 is executed, image formation by the first image forming apparatus 101 becomes impossible. However, only the other second image forming apparatus 102 feeds paper, forms both-side images, and ejects the print job. It is possible to continue. When the adjustment B is executed, the second image forming apparatus 102 cannot form an image, but the recording material can be conveyed. Therefore, after the first image forming apparatus 101 forms a double-sided image, the relay unit 201, By discharging the paper through the second image forming apparatus, the job can be continued. However, since the recording material cannot be conveyed in the second image forming apparatus 102 after the adjustment A is executed, the print job is interrupted even when the first image forming apparatus 101 can form an image. I must. Therefore, when the adjustment 1 or the adjustment B is executed in the image forming system, both sides of the image are formed by one image forming apparatus, and the productivity during that time is reduced by half, and the adjustment A is executed. In some cases, productivity in the meantime is zero. When these adjustments are executed at different timings between the two image forming apparatuses, the productivity is further greatly reduced.

  For example, consider the case where adjustment processing is performed in the situation of the reservation table shown in FIG. In the reservation table of FIG. 5A, the total number of print pages of job 2, which is the next job, is 700 sheets. 6A is an example of a table for managing the execution timing of the adjustment items provided in the EEPROM 35. The threshold value X for each adjustment item of the first image forming apparatus 101 and the second image forming apparatus 102 is shown in FIG. It consists of items such as an adjustment count value Y and the number of remaining print pages. FIG. 6A illustrates adjustment 1 that is an adjustment item of the first image forming apparatus 101 and adjustment A that is an adjustment item of the second image forming apparatus 102 when job 1 of the reservation table of FIG. Shows the table contents. As shown in FIG. 6A, the adjustment count value Y indicating the number of printed pages since the first image forming apparatus 101 executed adjustment 1 last time is 450, and the second image forming apparatus 102 executed adjustment A last time. The adjustment count value Y indicating the number of printed pages after 100 is 100.

  Regarding the first image forming apparatus 101, the conditional expression (Z mod X> (XY)) of (Expression 1) described above is satisfied from FIG. 2. Adjustment 1 is executed before execution and the adjustment count value Y is cleared. On the other hand, regarding the second image forming apparatus 102, since the conditional expression (Z mod X> (XY)) of (Expression 1) described above is not satisfied from FIG. 6A, the adjustment A is not executed. As a result, a table showing the threshold value X, the adjustment count value Y, the number of remaining print pages, etc. of each adjustment item immediately before execution of job 2 is as shown in FIG.

  When job 2 is started as it is, job 2 starts and adjustment A is executed in the second image forming apparatus 102 after 400 print pages. While the adjustment A is being executed, the job 2 is interrupted, and after the adjustment A is completed, the job 2 is resumed. However, after job 2 has been resumed and 100 print pages have been printed, the number of print pages in job 2 has now reached 500 in the first image forming apparatus 101, so adjustment 1 is executed. While the adjustment 1 is being executed, the second image forming apparatus 102 performs paper feeding and double-sided image formation, so that the execution of the job 2 is continued with the productivity reduced by half. Then, after the adjustment 1 is completed, the double-sided printing by the two image forming apparatuses is resumed, and the job 2 ends when the number of print pages reaches 700 from the start of the job 2. As described above, when the adjustment processing is performed independently (asynchronously) in each image forming apparatus, the adjustment A at which the productivity becomes zero is performed once, and the adjustment 1 at which the productivity is reduced by half is performed at different timings. When it is executed, productivity is lowered. Therefore, in the present embodiment, by adjusting the execution timing so that the adjustment A and the adjustment 1 are executed in parallel in each image forming apparatus, the adjustment 1 that halves the productivity is not apparent, and the entire image forming system is used. It is intended to improve the productivity by reducing the frequency of adjustments.

(2) Coordination of Adjustment Processing in Image Forming System Hereinafter, a method of coordinating adjustment processing in an image forming system including two image forming apparatuses will be described in detail. In order to minimize the productivity reduction of the duplex printing job, the adjustment execution timing is aligned so that the period in which the first image forming apparatus 101 and the second image forming apparatus 102 can simultaneously form images is maximized. Therefore, it is necessary to minimize the number of adjustments A at which the recording material cannot be discharged.

  Therefore, first, the first image forming apparatus 101 and the second image forming apparatus 102 perform necessary adjustment processing in each image forming apparatus before the start of the next print job in accordance with the adjustment processing sequence of FIG. 4 described above. Then, the CPU 30-2 of the second image forming apparatus 102 determines the remaining number of print pages W until the adjustment A is executed again after the next print job before the start of the next print job (Formula 2). ) And stored in the RAM 34-2.

W = (XY)-(Z mod X) (Formula 2)
In (Expression 2), (XY) indicates the number of remaining print pages until the next adjustment at the time when the print job is started, and (Z mod X) indicates the total number of print pages (Z) as a threshold value (X ) Indicates the remainder when divided, and indicates the number of printed pages after the adjustment items are implemented. Therefore, the value of W means that even if the threshold value of adjustment A is reduced by W, the number of adjustments A that are executed during the execution of the print job does not increase.

  Then, the first image forming apparatus 101 and the second image forming apparatus 102 start the next print job. When the adjustment count value Y of the adjustment item reaches the threshold value in the first image forming apparatus 101 or the second image forming apparatus 102 during execution of the print job, the adjustment item is any one of adjustment A, adjustment 1, and adjustment B. Therefore, the adjustment sequence to be executed differs in each image forming apparatus. Hereinafter, an adjustment sequence in each image forming apparatus for each adjustment item will be described using a flowchart.

(Pattern 1) When Adjustment Item is Adjustment A of Second Image Forming Apparatus 102 FIG. 7 is a flowchart showing a processing sequence when the adjustment item is Adjustment A of the second image forming apparatus 102. 7A shows a processing sequence executed in the CPU 30-1 (hereinafter abbreviated as CPU 1) of the first image forming apparatus 101, and FIG. 7B shows the CPU 30-2 of the second image forming apparatus 102. This is a processing sequence executed in (hereinafter abbreviated as CPU 2).

  First, the processing sequence of FIG. 7B will be described. In S501, the CPU 2 has reached the threshold value X of the adjustment counter A of the adjustment item A from the table (hereinafter abbreviated as the management table 2) for managing the execution timing of the adjustment item provided in the EEPROM 35-2. Determine whether or not. If the CPU 2 determines that the threshold value X has not been reached, the process proceeds to S507. If it is determined that the threshold value X has been reached, the process proceeds to S502. In step S <b> 502, the CPU 2 interrupts the currently executing print job, and transmits a signal A notifying that the CPU 2 performs the adjustment A to the CPU 1. In S503, the CPU 2 executes the adjustment mode in order to perform the adjustment A. In step S504, the CPU 2 determines whether the execution of the adjustment mode has been completed. If the adjustment mode has not been completed, the process in step S504 is repeated. If the process has been completed, the process proceeds to step S505. In S <b> 505, the CPU 2 clears the adjustment counter of the adjustment item A in the management table 2, and transmits a signal A ′ that notifies the CPU 2 that the processing of the adjustment A has been completed to the CPU 1. In S506, the CPU 2 resumes the interrupted job. In S507, the CPU 2 determines whether or not the print job has ended. If it has not ended, the process returns to S501, and if it has ended, the process ends.

  Next, the processing sequence of the CPU 1 in FIG. FIG. 7A shows processing started when the signal A transmitted by the CPU 2 is received in S502 of FIG. 7B. In S301, the CPU 1 interrupts the print job currently being executed. In S <b> 302, the CPU 2 determines from the data of a table (hereinafter abbreviated as management table 1) for managing the execution timing of the adjustment items provided in the EEPROM 35-1 and the conditional expression of (Expression 1) before the end of the print job. It is determined whether or not adjustment 1 is executed. If the adjustment 1 is not executed, the CPU 1 proceeds to S306, and if the adjustment 1 is executed, the CPU 1 proceeds to S303. In S <b> 303, the CPU 1 executes the adjustment mode in order to perform the adjustment 1. In S304, the CPU 1 determines whether or not the execution of the adjustment mode has been completed. If it has not been completed, the process of S304 is repeated. If it has been completed, the process proceeds to S305. In S305, the CPU 1 clears the adjustment counter of the adjustment item 1 in the management table 1. In S306, the CPU 1 determines whether or not the signal A ′ for notifying the end of the adjustment A process is received from the CPU 2, and if not, the process of S306 is repeated. If received, the process proceeds to S307. move on. In S307, the CPU 1 resumes the interrupted print job together with the CPU 2.

(Pattern 2) When Adjustment Item is Adjustment 1 of First Image Forming Apparatus 101 FIG. 8 is a flowchart showing a processing sequence when the adjustment item is Adjustment 1 of first image forming apparatus 101. 8A is a processing sequence executed by the CPU 1 of the first image forming apparatus 101, and FIG. 7B is a processing sequence executed by the CPU 2 of the second image forming apparatus 102.

  First, the processing sequence of FIG. 8A will be described. In S <b> 201, the CPU 1 determines whether the value Y of the adjustment counter of the adjustment item 1 has reached the threshold value X from the management table 1. If the CPU 1 determines that the threshold value X has not been reached, the process proceeds to S207. If the CPU 1 determines that the threshold value X has been reached, the process proceeds to S202. In S <b> 202, the CPU 1 interrupts the currently executing print job and transmits a signal 1 notifying that the CPU 1 performs the adjustment 1 to the CPU 2. In S <b> 203, the CPU 1 executes the adjustment mode in order to perform the adjustment 1. In S204, the CPU 1 determines whether or not the execution of the adjustment mode has been completed. If it has not been completed, the process of S204 is repeated. If it has been completed, the process proceeds to S205. In S205, the CPU 1 clears the adjustment counter of the adjustment item 1 in the management table 1, and transmits a signal 1 'notifying the CPU 1 that the adjustment 1 processing has been completed to the CPU 2. In S206, the CPU 1 resumes the interrupted job. In S207, the CPU 1 determines whether or not the print job has ended. If it has not ended, the process returns to S201, and if it has ended, the process ends.

  Next, the processing sequence of the CPU 2 in FIG. FIG. 8B shows processing started when the signal 1 transmitted by the CPU 1 is received in S202 of FIG. 8A. In step S701, the CPU 2 interrupts the currently executing print job. In step S <b> 702, the CPU 2 determines whether to execute the adjustment A before the end of the print job from the data in the management table 2 and the conditional expression (expression 1). If the adjustment A is not executed, the CPU 2 proceeds to S709, and if the adjustment A is performed, the CPU 2 proceeds to S703. In S702, the execution of the adjustment B is not determined because when the adjustment B is executed, the image forming operation in the image forming system is stopped and the productivity becomes zero.

  In step S709, the CPU 2 sets the following image forming operation so that the second image forming apparatus 102 performs double-sided printing in order to continue the print job, and the process advances to step S707. In the second image forming apparatus 102, the recording material is fed from sheet feeding cassettes 20-2, 21-2 and 22-2 which are sheet feeding units of the second image forming apparatus. After the paper is fed, the recording material on which the image is formed is switched back after passing through the fixing device 7-2, and the recording material is reversed at the front and back surfaces, and conveyed below the transfer roller 5-2. Via the path, the recording material is conveyed to the image forming unit for image formation on the back surface. Then, the recording material having the image formed on the back surface is discharged to the finisher unit 501 after passing through the fixing device 7-2. The double-sided printing in the second image forming apparatus 102 is continued until the CPU 2 receives the signal 1 'from the CPU 1 in S707 described later. In the process of S709, the CPU 2 is fed from the second image forming apparatus 102 immediately after the recording material conveyed from the first image forming apparatus 101 immediately before the CPU 1 executes the adjustment mode of adjustment 1. The conveyance of the recording material is controlled so that the recording material is conveyed.

  In S703, the CPU 2 determines whether or not a conditional expression shown below (Expression 3) is satisfied. In other words, the value of W indicating the number of remaining print pages until the adjustment A is executed again after the end of the print job is the number of remaining print pages until the next adjustment at the present time (XY). ) Or more.

W ≧ X−Y (Formula 3)
If the value of W is equal to or greater than the value of (X−Y), the CPU 2 proceeds to step S704 because the number of executions of the adjustment A in the print job currently being executed does not increase even if the adjustment A is performed here. However, if the value of W is less than the value of (X−Y), if the adjustment A is performed here, an adjustment operation that does not necessarily need to be performed for a print job that is currently being performed is performed. The number of times increases. Further, by performing the adjustment A, the double-sided printing by the second image forming apparatus 102 cannot be executed while the adjustment A is being performed, and the productivity during this time becomes zero, resulting in a decrease in productivity. It will be. Therefore, if the value of W is less than the value of (X−Y), the CPU 2 does not proceed to S704 but proceeds to S709. In S <b> 704, the CPU 2 executes the adjustment mode in order to perform the adjustment A. In step S705, the CPU 2 determines whether the execution of the adjustment mode has been completed. If the adjustment mode has not ended, the processing in step S705 is repeated. If the processing has ended, the process proceeds to step S706. In step S706, the CPU 1 clears the adjustment counter of the adjustment item A in the management table 2, and further subtracts the number of print pages raised to perform the adjustment A from the value of W stored in the RAM 34-2. The value is updated to (W− (XY)).

  In S707, the CPU 2 determines whether or not the signal 1 ′ for notifying the end of the adjustment 1 process is received from the CPU 1, and if not, the process of S707 is repeated. If received, the process proceeds to S708. move on. In step S708, the CPU 2 resumes the interrupted print job with both the CPUs 1. In the process of S709, if the second image forming apparatus 102 has been set to perform an image forming operation for performing double-sided printing, the CPU 2 returns to the setting for performing single-sided printing.

(Pattern 3) When Adjustment Item is Adjustment B of Second Image Forming Apparatus 102 FIG. 9 is a flowchart showing a processing sequence when the adjustment item is Adjustment B of the second image forming apparatus 102. FIG. 9A is a processing sequence executed by the CPU 1 of the first image forming apparatus 101, and FIG. 9B is a processing sequence executed by the CPU 2 of the second image forming apparatus 102.

  First, the processing sequence of FIG. 9B will be described. In S <b> 601, the CPU 2 determines from the management table 2 whether or not the value Y of the adjustment counter of the adjustment item B has reached the threshold value X. If the CPU 2 determines that the threshold value X has not been reached, the process proceeds to S607, and if it is determined that the threshold value X has been reached, the process proceeds to S602. In step S <b> 602, the CPU 2 interrupts the currently executing print job and transmits a signal B notifying the CPU 2 that the adjustment B is to be performed to the CPU 1. In step S <b> 603, the CPU 2 controls the image forming unit so that the recording material conveyed from the relay unit 201 is discharged to the finisher unit 501 and executes an adjustment mode in order to perform adjustment A. In step S604, the CPU 2 determines whether or not the execution of the adjustment mode has been completed. If the adjustment mode has not been completed, the process in step S604 is repeated. If the process has been completed, the process proceeds to step S605. In S605, the CPU 2 clears the adjustment counter of the adjustment item B in the management table 2, and transmits a signal B ′ notifying the CPU 2 that the processing of the adjustment B is completed to the CPU 1. In S606, the CPU 2 resumes the interrupted job. In S607, the CPU 2 determines whether or not the print job has ended. If it has not ended, the process returns to S601, and if it has ended, the process ends.

  Next, the processing sequence of the CPU 1 in FIG. FIG. 9A shows processing started when the signal B transmitted by the CPU 2 is received in S602 of FIG. 9B. In step S401, the CPU 1 interrupts the currently executing print job. In S <b> 402, the CPU 2 determines whether or not to execute the adjustment 1 before the end of the print job, based on the data in the management table 1 and the conditional expression (Expression 1). If the adjustment 1 is not performed, the CPU 1 proceeds to S408, and if the adjustment 1 is performed, the process proceeds to S403.

  In step S <b> 408, the CPU 1 sets the following image forming operation so that the first image forming apparatus 101 performs double-sided printing in order to continue the print job, and the process proceeds to step S <b> 406. In the first image forming apparatus 101, the recording material having the image formed on the front surface is switched back after passing through the fixing device 7-1, the front surface and the back surface of the recording material are reversed, and the conveyance path below the transfer roller 5-1. Then, in order to form an image on the back surface, the sheet is conveyed again to the image forming unit. Then, the recording material having the image formed on the back surface is conveyed to the relay unit 201 after passing through the fixing device 7-1. Double-sided printing in the first image forming apparatus 101 is continued until the CPU 1 receives a signal B ′ from the CPU 2 in S406 described later.

  In S <b> 403, the CPU 1 executes the adjustment mode in order to perform the adjustment 1. In S404, the CPU 1 determines whether or not the execution of the adjustment mode has ended. If not, the process in S404 is repeated. If it has ended, the process proceeds to S405. In S405, the CPU 1 clears the adjustment counter of the adjustment item 1 in the management table 1. In S406, the CPU 1 determines whether or not the signal B ′ for notifying the end of the adjustment B process is received from the CPU 2, and if not, the process of S406 is repeated. If received, the process proceeds to S407. move on. In S407, the CPU 1 resumes the interrupted print job together with the CPU 2. In the process of S408, if the first image forming apparatus 101 has been set to perform an image forming operation for performing double-sided printing, the CPU 1 returns to the setting for performing single-sided printing.

  In the above (Pattern 1) to (Pattern 3), when the first image forming apparatus 101 and the second image forming apparatus 102 can output an image, the recording material is the paper feeding unit 401 or the first image forming apparatus. Assume that a sheet is fed from a sheet feeding unit 101. When the first image forming apparatus 101 cannot output an image, the recording material is fed from a paper feeding unit in the second image forming apparatus 102.

  As described above, the adjustment of the first image forming apparatus 101 is also performed during the adjustment A in which image formation is impossible while minimizing the number of adjustments A in which the recording material cannot be discharged. As appropriate, it is possible to obtain the maximum period for outputting a double-sided job with two image forming apparatuses.

  For example, when a print job having the pattern shown in FIG. 5A is reserved, the first image forming apparatus 101 performs adjustment 1 before executing the print job according to the flow of FIG. Print job 2 is started. Accordingly, the processing up to this point is the same as the conventional one as shown in the table of FIG. However, the processing of the print job 2 proceeds, and after 400 sheets, the adjustment A is entered in the second image forming apparatus 102. At the same time, the first image forming apparatus 101 also follows the flow of FIGS. 7 (a) and 7 (b). Adjustment 1 is performed simultaneously. After that, when the print job 2 is resumed, the print job 2 having 700 print pages is completed without making another adjustment. As a result, the time required for the adjustment processing in which adjustment 1 and adjustment A were performed independently in each image forming apparatus is eliminated as compared with the conventional case, and a duplex printing job is executed by two image forming apparatuses. This improves productivity.

  Next, consider the case of the print job shown in FIG. In FIG. 10A, the total number of printed pages (Z) of the next print job is 700, the adjustment count value Y of adjustment 1 which is an adjustment item of the first image forming apparatus 101 is 200, and the second image The adjustment count value Y of adjustment A which is an adjustment item of the forming apparatus 102 is 100. Each image forming apparatus determines whether or not adjustment is performed during execution of the next print job. However, since neither of the image forming apparatuses satisfies the conditional expression (Z mod X> (XY)) of (Expression 1), the adjustment process is not executed before the print job is executed, and the print job is executed. Is done. At this time, the value of W is 200 (= (500−100) − (700 mod 500)) from W = (X−Y) − (Z mod X) in (Expression 2).

  When 300 sheets have elapsed, the adjustment 1 reaches the threshold value in the first image forming apparatus 101, and the adjustment mode is entered from the flow of FIG. At this time, in the second image forming apparatus 102, adjustment A is scheduled to be executed after 100 sheets (= (X−Y) = 500− (100 + 300)), and the value of W is 200. ) (W ≧ X−Y) is satisfied, the adjustment A is performed simultaneously from the flow of FIG. After performing the adjustment A, the value of W becomes 100 from W− (X−Y) = 200−100, and the value of W is also updated to 100. Thereafter, after the adjustment 1 and the adjustment A are completed, the image formation on both sides is resumed by the two image forming apparatuses, the remaining 400 sheets are printed, and the 700 print jobs are completed. Also in this case, as compared with the conventional case, the time during which the adjustment 1 and the adjustment A are performed independently is eliminated, and the time in which two-side jobs can be executed by two units is increased instead, so that the productivity is improved.

  Further, in the image forming system, it is assumed that a large amount of print jobs such as the reservation table in FIG. 10B are generated. However, in this embodiment, a large amount of print jobs is more effective in suppressing productivity reduction. Can get more. In the case of FIG. 10C, the values of the adjustment 1 and the threshold A of the adjustment A, the adjustment count value Y, etc. when the print job 2 of FIG. Adjustment A of the image forming apparatus 102 and adjustment 1 of the first image forming apparatus 101 are executed after printing the next number of sheets. Adjustment A is executed after 200 sheets (*), after 700 sheets, after 1200 sheets, and after 1700 sheets. Adjustment 1 is performed after 200 sheets, after 500 sheets, after 700 sheets (*), after 1000 sheets, and after 1200 sheets. (*) After 1500 sheets, after 1700 sheets (*), and after 2000 sheets. At this time, (*) indicates a point in time when the adjustment is advanced from the original predetermined number according to the control of the present embodiment. As a result, the number of times of adjustment A at which the productivity becomes zero is 4 times, and the number of times of adjustment 1 at which the productivity is reduced to half is actually 8 times. It becomes.

  On the other hand, in the conventional example, adjustment A is executed after 300, 800, 1300, and 1800, and adjustment 1 is performed after 200, 500, 800, 1100, 1400, This is executed after 1700 sheets and 2000 sheets. That is, the number of adjustments A at which productivity becomes zero remains unchanged at four times, but the number of adjustments 1 at which productivity is reduced by half is actually seven, except for 800 sheets that are executed simultaneously with adjustment A. Apparently 6 times. The number of adjustments 1 actually performed is 8 in the present embodiment, but 7 in the conventional example, which is smaller in the conventional example. However, since the execution timing of the adjustment process is aligned in the present embodiment, the apparent number of adjustments 1 is twice as compared with the conventional example, and the productivity is improved.

  As described above, according to the present embodiment, it is possible to suppress a decrease in productivity due to the execution of the adjustment mode. That is, by synchronizing the execution timing of the adjustment processing in the first image forming apparatus and the second image forming apparatus, the apparent number of adjustments can be reduced, and as a result, the downtime during execution of the print job can be reduced.

  In the above-described embodiment, the CPUs of the first image forming apparatus and the second image forming apparatus control suspension and resumption of image formation in the adjustment mode. However, in addition to these CPUs, a print control apparatus that controls the operation of the two image forming apparatuses may control interruption and resumption of image formation. That is, the print control apparatus manages the execution timing of the adjustment mode, and instructs the first and second image forming apparatuses to execute the adjustment mode, interrupt the image forming operation, and restart the image forming operation.

20, 21, 22 Paper cassette 30-1, 30-2 CPU
101 First image forming apparatus 102 Second image forming apparatus

Claims (10)

When the first image forming apparatus and the second image forming apparatus are connected to the downstream side of the first image forming apparatus and a duplex printing job is executed, the first image forming apparatus forms an image on the first surface of the recording material, In the image forming system for forming an image on the second surface of the recording material with the second image forming apparatus by inverting the front and back of the recording material,
When one of the first image forming apparatus and the second image forming apparatus interrupts a print job and performs an image forming adjustment operation, the other image forming apparatus performs the print job. If there is another image forming adjustment operation to be executed before the end of the printing operation, the print job in the other image forming apparatus is interrupted, and the adjustment operation in the one image forming apparatus and the adjustment operation in the other image forming apparatus are performed. An image forming system comprising control means for controlling the execution timing of the adjustment operation so as to be executed in parallel. In the second image forming apparatus, when a print job is interrupted and an adjustment operation is performed in which the recording material conveyed from the first image forming apparatus cannot be conveyed,
If there is an image forming adjustment operation to be executed before the end of the print job in the first image forming apparatus, the control unit performs the adjusting operation in the second image forming apparatus and the first image forming operation. The image forming system according to claim 1, wherein the adjustment operation in the apparatus is executed in parallel. The first image forming apparatus has a function of forming an image on both sides of a recording material,
In the second image forming apparatus, when a print job is interrupted and an adjustment operation capable of conveying the recording material conveyed from the first image forming apparatus is executed,
The control means includes
If there is an image forming adjustment operation to be executed before the end of the print job in the first image forming apparatus, an adjustment operation in the second image forming apparatus and an adjustment operation in the first image forming apparatus In parallel,
If there is no image forming adjustment operation to be executed before the end of the print job in the first image forming apparatus, the first image forming apparatus forms an image on the first surface and the second surface of the recording material. The image forming system according to claim 1, wherein the image forming system is performed. The second image forming apparatus has a function of forming an image on both sides of a recording material. In the first image forming apparatus, when a print job is interrupted and an adjustment operation is performed,
The control means includes
If there is an adjustment operation in which the recording material transported from the first image forming apparatus to be executed before the end of the print job in the second image forming apparatus cannot be transported, the first image forming apparatus An adjustment operation and an adjustment operation in the second image forming apparatus are executed in parallel;
If there is no adjustment operation in which the recording material conveyed from the first image forming apparatus to be executed before the end of the print job in the second image forming apparatus cannot be performed, the second image forming apparatus The image forming system according to claim 1, wherein image formation is performed on the first surface and the second surface of the recording material.   The control unit executes the adjustment operation in parallel with the adjustment operation in the first image forming apparatus even if there is an adjustment operation to be executed in the second image forming apparatus before the print job is completed. If the number of adjustment operations to be executed by the second image forming apparatus increases before the end of the print job, the adjustment is performed in parallel with the adjustment operation of the first image forming apparatus. 5. The image according to claim 4, wherein the second image forming apparatus forms an image on the first surface and the second surface of the recording material without performing an adjustment operation in the second image forming apparatus. Forming system. When the first image forming apparatus and the second image forming apparatus are connected to the downstream side of the first image forming apparatus and a duplex printing job is executed, the first image forming apparatus forms an image on the first surface of the recording material, In the printing control apparatus that reverses the front and back of the recording material and forms an image on the second surface of the recording material with the second image forming apparatus,
When one of the first image forming apparatus and the second image forming apparatus interrupts a print job and performs an image forming adjustment operation, the other image forming apparatus performs the print job. If there is another image forming adjustment operation to be executed before the end of the printing operation, the print job in the other image forming apparatus is interrupted, and the adjustment operation in the one image forming apparatus and the adjustment operation in the other image forming apparatus are performed. And a control unit that controls the execution timing of the adjustment operation so that the control process is executed in parallel. In the second image forming apparatus, when a print job is interrupted and an adjustment operation is performed in which the recording material conveyed from the first image forming apparatus cannot be conveyed,
If there is an image forming adjustment operation to be executed before the end of the print job in the first image forming apparatus, the control unit performs the adjusting operation in the second image forming apparatus and the first image forming operation. The print control apparatus according to claim 6, wherein the adjustment operation in the apparatus is executed in parallel. The first image forming apparatus has a function of forming an image on both sides of a recording material,
In the second image forming apparatus, when a print job is interrupted and an adjustment operation capable of conveying the recording material conveyed from the first image forming apparatus is executed,
The control means includes
If there is an image forming adjustment operation to be executed before the end of the print job in the first image forming apparatus, an adjustment operation in the second image forming apparatus and an adjustment operation in the first image forming apparatus In parallel,
If there is no image forming adjustment operation to be executed before the end of the print job in the first image forming apparatus, the first image forming apparatus forms an image on the first surface and the second surface of the recording material. The printing control apparatus according to claim 6, wherein the printing control apparatus is performed. The second image forming apparatus has a function of forming an image on both sides of a recording material. In the first image forming apparatus, when a print job is interrupted and an adjustment operation is performed,
The control means includes
If there is an adjustment operation in which the recording material transported from the first image forming apparatus to be executed before the end of the print job in the second image forming apparatus cannot be transported, the first image forming apparatus An adjustment operation and an adjustment operation in the second image forming apparatus are executed in parallel;
If there is no adjustment operation in which the recording material conveyed from the first image forming apparatus to be executed before the end of the print job in the second image forming apparatus cannot be performed, the second image forming apparatus The print control apparatus according to claim 6, wherein image formation is performed on the first surface and the second surface of the recording material.   The control unit executes the adjustment operation in parallel with the adjustment operation in the first image forming apparatus even if there is an adjustment operation to be executed in the second image forming apparatus before the print job is completed. If the number of adjustment operations to be executed by the second image forming apparatus increases before the end of the print job, the adjustment is performed in parallel with the adjustment operation of the first image forming apparatus. 10. The printing according to claim 9, wherein the second image forming apparatus forms an image on the first surface and the second surface of the recording material without performing an adjustment operation in the second image forming apparatus. Control device.

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