JP2013202907A - Image forming system and control method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a serial tandem type image forming system consisting of a plurality of image forming apparatuses, in which a downtime of the system is reduced by performing a double-sided printing job as quick as possible while avoiding an influence caused by an operation of adjusting the image forming apparatuses.SOLUTION: An image forming system is a serial tandem type image forming system, in which each of an upstream machine 200 and a downstream machine 300 is configured to form images on both sides of a sheet. A controller of the system is configured to, when performing a double-sided printing job, in the state in which an adjusting operation is performed in one of the upstream machine 200 and the downstream machine 300, perform the double-sided printing job by operating only the other image forming apparatus in which the adjusting operation is not performed, and after ending the adjusting operation of one image forming apparatus, a mode is shifted to a mode (tandem mode) of performing the double-sided printing job in a series.

Description

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

  In recent years, a series tandem type image forming system in which a plurality of image forming apparatuses are connected in series has been put into practical use. For example, in a series tandem type image forming system in which two image forming apparatuses are connected in series, an upstream image forming apparatus (upstream machine) forms an image on one side of a sheet, and a downstream image forming apparatus The (downstream machine) executes an operation of forming an image on the other side of the sheet. Thereby, in the serial tandem type image forming system, productivity can be dramatically improved as compared with the case where a single image forming apparatus forms images on both sides of a sheet.

  For example, Patent Documents 1 and 2 disclose an image forming system in which an upstream machine and a downstream machine perform image formation on a different sheet surface to execute a job including double-sided printing. In this image forming system, each image forming apparatus is configured to be able to form images on both sides of a sheet by itself. As a result, even when one image forming apparatus fails and becomes unusable, the other image forming apparatus operates to execute a job including double-sided printing.

JP 2005-22243 A Japanese Patent Laid-Open No. 10-86455

  By the way, an image forming apparatus used in such an image forming system has performance related to image formation at a predetermined timing, for example, at the time of starting the system so that an image forming accuracy of a level satisfying a predetermined standard can be obtained. Execute the adjustment operation to be adjusted. During the period when one or both of the image forming apparatuses are executing the adjustment operation, the job cannot be executed by the image forming apparatus. There is a problem that it cannot be executed. Therefore, when a job is acquired during the adjustment operation period, it takes time until the job is actually executed, resulting in a disadvantage that the system downtime increases.

  Further, in the methods disclosed in Patent Documents 1 and 2, if one of the image forming apparatuses breaks down, it is impossible to return to the operation state autonomously such that maintenance of a worker is necessary. Inconvenience arises that the state in which the performance is greatly reduced continues for a long time.

  The present invention has been made in view of such circumstances, and an object of the present invention is to reduce downtime associated with an adjustment operation in a series tandem type image forming system including a plurality of image forming apparatuses and to perform double-sided printing. It is to suppress the decrease in productivity as much as possible.

  In order to solve such a problem, the first invention includes a first image forming apparatus that forms an image on one side or both sides of a sheet, and the first image forming apparatus that is connected in series to the first image forming apparatus. A second image forming apparatus that forms an image on one side or both sides of the paper, and the first image forming apparatus and the first image forming apparatus according to the job. And an image forming system that controls each of the two image forming apparatuses. In this image forming system, the control device executes an adjustment operation in which one of the first image forming device and the second image forming device adjusts the performance related to image formation when executing a job including double-sided printing. In the case where the image forming apparatus does not perform the adjustment operation, the other image forming apparatus executes the job by the first double-sided printing process in which images are formed on both sides of the sheet, and the adjustment operation of one image forming apparatus is completed. Thereafter, the first image forming apparatus forms an image on one side of the paper, and the second image forming apparatus forms a image on the other side of the paper, and the mode is set to execute the job by the second double-sided printing process. Transition.

  Here, in the first invention, the control device performs the second double-sided printing process when the adjustment operation of one of the image forming apparatuses is completed prior to the end of the job by the first double-sided printing process. It is preferable to execute the remainder of printing for the job.

  In the first aspect of the invention, when both the first image forming apparatus and the second image forming apparatus are performing the adjustment operation, the control device until one of the image forming apparatuses completes the adjustment operation. It is preferable to execute the job after waiting.

  In the first invention, when the adjustment operation of one of the image forming apparatuses is completed, the control device shifts to a mode in which the job is executed by the second double-sided printing process based on the remaining print portion related to the job. It is preferable to determine whether or not to do so.

  Further, according to the first aspect of the present invention, a sheet connected to the second image forming apparatus in series, accepts a sheet discharged from the second image forming apparatus, and discharges the sheet onto a sheet discharge tray. It is preferable to further have an apparatus. In this case, the control device controls the paper discharge device so that the boundary between the paper on which the image is formed by the first double-sided printing process and the paper on which the image is formed by the second double-sided printing process can be understood. Is desirable.

  According to a second aspect of the present invention, there is provided a first image forming apparatus that forms an image on one side of a sheet or both sides of a sheet, and the first image forming apparatus that is connected in series and discharged from the first image forming apparatus. And a second image forming apparatus that forms an image on one side of the paper or both sides of the paper, and is configured to receive the printed paper. In this control method, the first image forming apparatus and the second image forming apparatus acquire a job that includes double-sided printing during a period in which one of the first image forming apparatus and the second image forming apparatus is performing an adjustment operation for adjusting performance related to image formation. Step, a second step in which the other image forming apparatus that has not performed the adjustment operation executes a job by a first double-sided printing process in which an image is formed on both sides of the paper, and an adjustment operation of one image forming apparatus is completed After that, the mode in which the first image forming apparatus forms an image on one side of the sheet and the second image forming apparatus forms the image on the other side of the sheet and executes the job by the second duplex printing process. And a third step of shifting to.

  According to the present invention, when one of the first image forming apparatus and the second image forming apparatus is performing the adjustment operation, the duplex printing process of the other image forming apparatus alone that is not performing the adjustment operation Can execute the job. Therefore, it is possible to start a job in advance in the other image forming apparatus in operation without waiting for the state in which both image forming apparatuses operate normally. Further, the image forming apparatus during the adjustment operation can autonomously return to an operation state in which image formation is possible after the adjustment operation is completed. As a result, it is possible to execute a job by serial double-sided printing processing, and thereafter, productivity can be improved. Therefore, it is possible to reduce the downtime and suppress the reduction in productivity in double-sided printing as much as possible.

Configuration diagram schematically showing an image forming system 6 is a flowchart showing an operation procedure of the image forming system according to the first embodiment. The flowchart which shows the detail of the printing process of step 10 concerning 1st Embodiment. Explanatory drawing schematically showing the state of the discharged paper Explanatory diagram schematically showing the concept of job execution Explanatory diagram schematically showing the concept of job execution The flowchart which shows the detail of the printing process of step 10 concerning 2nd Embodiment. Explanatory diagram schematically showing the concept of job execution

(First embodiment)
FIG. 1 is a configuration diagram schematically showing an image forming system according to the present embodiment. The image forming system includes a large-capacity paper feeding device 100, an upstream device 200, a downstream device 300, and a paper discharge device 400. Each of the upstream machine 200 and the downstream machine 300 is an electrophotographic image forming apparatus such as a copying machine, for example, and this image forming system is configured by connecting two image forming apparatuses having the same configuration in series. This is a serial tandem type image forming system. In the serial tandem type image forming system, one image forming apparatus (for example, upstream machine 200) forms an image on the surface of paper P, and the other image forming apparatus (for example, downstream apparatus 300) forms an image on the back surface of paper P. By forming it, it is possible to increase the speed of a job including double-sided printing.

  The large-capacity paper feeding device 100 is a device for accumulating and storing a large amount of paper P and feeding the paper P to the upstream machine 200 and the downstream machine 300. Connected in series to the side. The large-capacity paper feeding device 100 is mainly configured by a paper feeding unit 110. The paper feeding unit 110 is composed of a plurality of paper feeding trays, for example, three paper feeding trays 111 to 113, and each of the paper feeding trays 111 to 113 receives paper P of the same size / type or different size / type. Can be accommodated. The paper feed unit 110 feeds the paper P corresponding to the job from the corresponding paper feed trays 111 to 113 one by one and transports it to the upstream machine 200.

  The upstream machine 200 is an apparatus that forms an image on the paper P, and is connected in series to the downstream side of the large-capacity paper feeder 100. The upstream machine 200 is configured to receive the paper P discharged from the upstream device, that is, the large-capacity paper feeder 100, and the paper P from the large-capacity paper feeder 100 or the paper P held by itself. An image can be formed. The upstream machine 200 is configured mainly by an image forming unit 230, a fixing unit 240, a transport unit 250, and a control unit 260.

  The image forming unit 230 transfers a full-color image onto the paper P by arranging a plurality of photoconductors facing one intermediate transfer belt in the vertical direction. Specifically, the image forming unit 230 includes four image forming units 230Y, 230M, 230C, and 230K corresponding to yellow, magenta, cyan, and black, and an intermediate transfer unit 235. Hereinafter, the configuration of the image forming unit 230Y corresponding to yellow will be described, but the configurations of the image forming units 230M to 230K corresponding to other colors are the same.

  The image forming unit 230Y includes a photosensitive drum 231 and a developing unit 232. The developing unit 232 is mainly composed of, for example, a charging unit, an exposure unit, and a developing unit. The charging unit uniformly charges the peripheral surface of the photosensitive drum 231. The exposure unit irradiates the photosensitive drum 231 with laser light to form an electrostatic latent image on the surface thereof. The developing unit makes the latent image formed on the surface of the photosensitive drum 231 visible with toner. As a result, an image (toner image) is formed on the photosensitive drum 231. The image formed on the photosensitive drum 231 is sequentially transferred to a predetermined position on the intermediate transfer belt 236 constituting the intermediate transfer unit 235.

  The image composed of each color transferred onto the intermediate transfer belt 236 is transferred onto the paper P conveyed at a predetermined timing by the transfer roller 237. The transfer roller 237 is disposed in pressure contact with the intermediate transfer belt 236 and forms a nip portion (transfer nip portion) with the intermediate transfer belt 236.

  The transport unit 250 includes a paper feed tray 251 and a transport unit including a number of transport rollers and guide members. The paper P accommodated in the paper feed tray 251 or the paper received from the large-capacity paper feeder 100 is transported by each transport roller, and the transfer nip portion is synchronized with an image carried by the intermediate transfer belt 235 at a predetermined timing. It is conveyed to. As the sheet passes through the transfer nip, an image is transferred to one side of the sheet P, and the sheet P on which the image has been transferred is conveyed to the fixing unit 240.

  The fixing unit 240 includes a heating roller and a pressure roller. A heat source (not shown) is built in the heating roller, and the heating roller is controlled to a predetermined temperature by this heat source. When the paper P passes through the nip portion (fixing nip portion) between the heating roller and the pressure roller in the conveyance process of the paper P, the image transferred to the paper P is heated and pressed, and thereby the image is transferred to the paper. Fixed to P.

  The paper P on which the fixing process has been performed by the fixing unit 240 is discharged out of the upstream machine 200 by a paper discharge roller. In this case, as will be described later, on the premise that double-sided printing is performed in cooperation with the downstream machine 300, when the paper P sent out from the fixing unit 240 is reversed and discharged to the downstream machine 300, the paper P Is transferred to the reversing roller below by the switching gate. The reverse roller pinches the rear end of the conveyed paper P, reverses the paper P by reverse feeding, and feeds the paper P to the paper discharge roller. As a result, the paper P whose front and back are reversed from when the paper passes through the fixing nip is discharged out of the upstream machine 200 by the paper discharge roller.

  Further, the upstream machine 200 can form an image on both sides of the paper P by itself as well as forming an image on one side of the paper P. That is, when image formation is performed on both sides of the sheet P only by the upstream machine 200, the sheet P sent from the fixing unit 240 after image formation on one side of the sheet P is reversed by the reversing roller below the switching gate. It is conveyed to. The reversing roller pinches the rear end of the conveyed paper P, reverses the paper P by reverse feeding, and sends the paper P to the refeed conveyance path. The paper P sent out to the re-feed transport path is transported by the transport roller and returned to the transfer nip portion, thereby being used for image formation with the other surface of the paper P as a processing target.

The control unit 260 has a function of controlling the image forming operation by the upstream device 200 in an integrated manner. The control unit 260 controls each unit (the image forming unit 230, the fixing unit 240, and the conveyance unit 250) of the upstream machine 200 based on a job commanded by the user, thereby executing a series of processes shown below. As a result, an image corresponding to the job is formed on the paper P.
(1) Charge the photosensitive drum 231 by the charging unit (2) Form an electrostatic latent image on the photosensitive drum 231 by the exposure unit (3) Adhere toner to the electrostatic latent image formed by the developing unit (4) The image on the photosensitive drum 231 is transferred to the paper P. (5) The fixing process is performed on the paper P on which the image is transferred.

  Image data serving as a base for image formation is based on the assumption that the image forming system includes a document reading device (not shown), and when the user instructs a job through the operation unit or the like, the document reading device reads the document. The control unit 260 can acquire image data corresponding to the job. Further, the image data may be acquired together with a job from a personal computer connected to the image forming apparatus or another image forming apparatus.

  Note that the upstream machine 200 can simply carry the inside of the machine without forming an image on the paper P and discharge it outside the machine.

  The downstream machine 300 is an apparatus that forms an image on the paper P, and is connected in series to the downstream side of the upstream machine 200. The downstream machine 300 is configured to receive the paper P discharged from the upstream apparatus, that is, the upstream machine 200, and forms an image on the paper P from the upstream machine 200 or the paper P held by itself. can do. The downstream machine 300 is mainly configured by an image forming unit 330, a fixing unit 340, a transport unit 350, and a control unit 360. The downstream machine 300 is an image forming apparatus having the same machine configuration as that of the upstream machine 200, and the individual elements 330 to 360 constituting this correspond to the individual elements 230 to 260 constituting the upstream machine 200. ing. Further, as with the upstream machine 200, the downstream machine 300 not only forms an image on one side of the paper P, but also forms an image on each side of the paper P alone, Without being formed, the inside of the machine can be simply transported and discharged out of the machine.

  The paper discharge device 400 discharges the paper P discharged from the downstream machine 300 to the paper discharge tray 410 and accumulates it on the paper discharge tray 410. Further, the paper discharge device 400 can sort and stack the discharged paper P at different stacking positions on the paper discharge tray 410 in units of jobs, units of copies, or arbitrary units.

  In the image forming apparatus having such a configuration, the control unit 260 included in the upstream machine 200 is configured to be able to communicate with the large-capacity paper feeding apparatus 100, the downstream machine 300, and the paper discharge apparatus 400, and integrates the entire image forming system. It also functions as a control device for controlling automatically. The control unit 260 as such a control device sets the operation mode of the image forming system to a tandem mode in which both the upstream device 200 and the downstream device 300 are operated, except for an adjustment operation execution period described later. In this tandem mode, when the control unit 260 acquires a job, the control unit 260 forms an image on one side of the paper P by either the upstream machine 200 or the downstream machine 300, or the upstream machine 200 forms an image on one side of the paper P. The downstream machine 300 forms an image on the other side of the paper P and forms an image on both sides of the paper P.

  Further, the control unit 260 instructs the upstream machine 200 and the downstream machine 300 to execute the adjustment operation as necessary. The adjustment operation may be instructed simultaneously to both the upstream device 200 and the downstream device 300, for example, when the image forming system is activated, or the maintenance counter reaches a predetermined count value. In some cases, it is instructed only to an apparatus that requires an adjustment operation.

  This adjustment operation is for adjusting the performance related to image formation. Even if the image forming apparatus that is performing the adjustment operation acquires a job during the period until the completion, the image forming apparatus performs processing for the job. Image formation cannot be performed. Although the upstream machine 200 and the downstream machine 300 are image forming apparatuses having the same mechanical configuration, the periods required for the adjustment operation tend not to coincide with each other depending on individual differences or differences in the usage frequency of the apparatuses.

  The adjustment operation includes (1) color misregistration correction in which a registration mark for each color is formed on the intermediate transfer belt, and an image writing position is corrected by detecting a misregistration amount for each color from the formation position of each color registration mark. Density adjustment that adjusts the density of a solid image for each color. (3) Tone correction that forms a multi-tone gradation pattern for each color on the intermediate transfer belt and detects the density to correct the tone of the reproduced image. (4) Light amount correction for causing a laser diode to emit light and correcting the light amount to an appropriate value.

  When one of the upstream machine 200 and the downstream machine 300 is performing an adjustment operation when executing a job that includes double-sided printing, the control unit 260 executes the job by the first double-sided printing process. . Here, the first double-sided printing process is a process in which the other image forming apparatus that has not performed the adjustment operation forms images on both sides of the paper P, and is hereinafter referred to as “single-sided double-sided printing process”. Then, after the adjustment operation of one image forming apparatus is completed, the control unit 260 shifts to a mode (tandem mode) in which a job is executed by the second duplex printing process. Here, the second duplex printing process is a process in which the upstream machine 200 forms an image on one side of the paper P and the downstream machine 300 forms an image on the other side of the paper P. "Double-sided printing process".

  FIG. 2 is a flowchart showing an operation procedure of the image forming system according to the present embodiment, and specifically, a flowchart showing an operation procedure of the image forming system accompanying execution of the adjustment operation. The processing shown in this flowchart is called by the establishment of the execution condition of the adjustment operation as a trigger, and is executed by the control unit 260 that is a control device of the image forming system. Conditions for executing the adjustment operation include, for example, when the maintenance counter of the upstream device 200 or the downstream device 300 reaches a predetermined count value when the image forming system is activated, or when an instruction to execute the adjustment operation is received from the user. This is established under a predetermined condition that requires an adjustment operation.

  First, in step 1 (S1), the control unit 260 instructs execution of the adjustment operation. For example, in the case of a scene such as when the image forming system is activated, the control unit 260 instructs the upstream device 200 and the downstream device 300 to execute the adjustment operation, and the maintenance counter reaches a predetermined count value. Instructs the apparatus including the counter that has reached the count value to execute the adjustment operation. In response to this adjustment operation execution instruction, the instructed apparatus starts executing the adjustment operation, and completes the adjustment operation upon completion of a predetermined correction process.

  In step 2 (S2), the control unit 260 determines whether a job has been acquired. The job can be acquired from a PC connected to the image forming system or can be acquired from an input unit included in the image forming system. If a negative determination is made in step 2, that is, if the control unit 260 has not acquired a job, the process proceeds to step 3 (S3). On the other hand, if an affirmative determination is made in step 2, that is, if the control unit 260 acquires a job, the process proceeds to step 6 (S6) described later.

  In step 3, the control unit 260 determines whether both the upstream machine 200 and the downstream machine 300 are performing the adjustment operation. If an affirmative determination is made in step 3, that is, if both of the adjustment operations are being executed, the process returns to step 2. On the other hand, if a negative determination is made in step 3, the process proceeds to step 4 (S4).

  Here, as a case in which a negative determination is made in Step 3, (a) in a scene in which both the upstream machine 200 and the downstream machine 300 are instructed to execute the adjustment operation, one of them still executes the adjustment operation. When the other has completed the adjustment operation, (b) In a scene where both the upstream machine 200 and the downstream machine 300 are instructed to execute the adjustment operation, both have completed the adjustment operation. When the adjustment operation is instructed to one of the upstream machine 200 and the downstream machine 300 and the adjustment operation is still being executed, (d) the adjustment operation to either the upstream machine 200 or the downstream machine 300 This corresponds to the case where the adjustment operation has been completed in the scene in which the execution instruction is issued.

  In step 4, the control unit 260 determines whether only one of the upstream machine 200 and the downstream machine 300 is performing the adjustment operation. If an affirmative determination is made in step 4, that is, if only one unit is performing the adjustment operation (above (a), (c)), the process returns to step 2. On the other hand, when a negative determination is made in step 4, that is, when both the upstream machine 200 and the downstream machine 300 have completed the adjustment operation (above (b) and (d)), the process proceeds to step 5 (S5). .

  In Step 5, the control unit 260 shifts the operation mode of the image forming system to the tandem mode. When the mode is shifted to the tandem mode, the control unit 260 acquires a job in a state where both the upstream device 200 and the downstream device 300 are in operation (a state where printing according to the job is possible) until the execution of the adjustment operation is instructed again. Wait.

  In step 6, the control unit 260 determines whether or not both the upstream machine 200 and the downstream machine 300 are executing the adjustment operation as in the process of step 3. If an affirmative determination is made in step 6, the process returns to step 6. By such a loop, the job is executed after waiting until either the upstream machine 200 or the downstream machine 300 completes the adjustment operation. On the other hand, if a negative determination is made in step 6, the process proceeds to step 7 (S7).

  In step 7, the control unit 260 determines whether only one of the upstream machine 200 and the downstream machine 300 is performing the adjustment operation, as in the process of step 4. If a negative determination is made in step 6, the process proceeds to step 8 (S8). On the other hand, if an affirmative determination is made in step 7, the process proceeds to step 10 (S10) described later.

  In step 8, the control unit 260 shifts to the tandem mode as in the process of step 5. In step 9 (S9), the control unit 260 starts print processing corresponding to the job by both the upstream machine 200 and the downstream machine 300. Specifically, the control unit 260 forms an image on one side of the paper P by selectively using either the upstream machine 200 or the downstream machine 300 when executing a job that includes single-sided printing. In addition, when executing a job including double-sided printing, the control unit 260 forms an image on one side of the paper P by the upstream machine 200 and forms an image on the other side of the paper P by the downstream machine 300. By forming, images are formed on both sides of the paper P.

  On the other hand, in step 10 (S10), the control unit 260 starts the printing process prior to shifting to the tandem mode. FIG. 3 is a flowchart showing details of the printing process in step 10.

  In step 11 (S11), the control unit 260 determines whether or not the job content is duplex printing. If a negative determination is made in step 11, that is, if the content of the job is single-sided printing, the process proceeds to step 12 (S12). On the other hand, if an affirmative determination is made in step 11, that is, if the content of the job is double-sided printing, the process proceeds to step 14 (S14) described later.

  In step 12, the control unit 260 executes the job using the other image forming apparatus that is not performing the adjustment operation among the upstream machine 200 and the downstream machine 300. As a result, the one-side printing process in which the other image forming apparatus that is not performing the adjusting operation among the upstream machine 200 and the downstream machine 300 forms an image on one surface of the paper P is started.

  In step 13 (S13), the control unit 260 determines whether or not all printing related to the job has been completed. If an affirmative determination is made in step 13, that is, if all printing related to the job has been completed, the process returns to step 2 described above. On the other hand, if a negative determination is made in step 13, that is, if all the printing related to the job has not been completed, the processing returns to step 13.

  On the other hand, in step 14, the control unit 260 executes the job using the other image forming apparatus that is not performing the adjustment operation among the upstream machine 200 and the downstream machine 300. Thereby, the single-sided double-sided printing process is started.

  For example, when only the downstream machine 300 is performing the adjustment operation, the upstream machine 200 is used to form images on both sides of the paper P. In other words, the upstream machine 200 forms an image on one side of the paper P for the paper P supplied from the large-capacity paper feeding device 100 or the paper feed tray owned by the upstream machine 200, and then on the other side. Also perform image formation. Then, the paper P on which images are formed on both sides is discharged to the downstream machine 300 that is executing the adjustment operation. In the downstream machine 300, the paper P from the upstream machine 200 is discharged to the paper discharge device 400 in correspondence with a period of the adjustment operation that does not hinder paper conveyance, for example, during correction calculation.

  On the other hand, when only the upstream machine 200 is performing the adjustment operation, the downstream machine 300 is used to form images on both sides of the paper P. That is, the downstream machine 300 targets the paper P supplied from the large-capacity paper feeder 100 via the upstream machine 200 that is performing the adjustment operation, or the paper P fed from the paper feed tray held by itself. After the image is formed on one side of the paper P, the image is also formed on the other side. The paper P on which images are formed on both sides is discharged to the paper discharge device 400.

  In step 15 (S15), the control unit 260 determines whether or not all printing related to the job has been completed. If an affirmative determination is made in step 15, that is, if all printing related to the job has been completed, the process returns to step 2 described above. On the other hand, if a negative determination is made in step 15, that is, if all of the printing related to the job has not been completed, the process proceeds to step 16 (S16).

  In step 16, the control unit 260 determines whether or not the adjustment operation has been completed for one of the image forming apparatuses for which it has been determined in step 7 that the adjustment operation is still being executed. If an affirmative determination is made in step 16, that is, if the adjustment operation is completed, the process proceeds to step 17 (S17). On the other hand, if a negative determination is made in step 16, that is, if the adjustment operation is not completed, the process returns to step 15.

  In step 17, the control unit 260 stops the single-sided double-sided printing process and then shifts to the tandem mode. In step 18 (S18), the control unit 260 executes the remaining part of the printing related to the job using both the upstream machine 200 and the downstream machine 300. As a result, serial double-sided printing is started for the remainder of the printing.

  In the case of shifting to the tandem mode, a period for performing an adjustment operation for tandem that corrects image positional deviation, density deviation, color tone deviation, etc. between the upstream machine 200 and the downstream machine 300 is interposed. Also good.

  Further, the control unit 260 can recognize the boundary between the final sheet on which an image is formed by the single-sided double-sided printing process and the first sheet on which an image is formed by the double-sided printing process after shifting to the tandem mode. The paper discharge device 400 may be controlled. Specifically, as shown in FIG. 4A, a sheet P1 on which an image is formed by a single-sided double-sided printing process and a sheet P2 on which an image is formed by a double-sided printing process after shifting to the tandem mode are used. The sheets may be sorted and accumulated at different positions on the discharge tray 410. Alternatively, as shown in FIG. 5B, a sheet P1 on which an image is formed by single-sided double-sided printing processing and a sheet P2 on which an image is formed by both the upstream machine 200 and the downstream machine 300 in the tandem mode. An insertion sheet P3 may be interposed therebetween. For example, the insertion paper P3 may be a paper of a different type (color, paper type, basis weight, etc.) from the papers P1 and P2, or the paper output position is offset from the papers P1 and P2 and the insertion paper P3 may be easily identified.

  Thus, in this embodiment, the image forming system is a serial tandem image forming system, and each of the upstream machine 200 and the downstream machine 300 is configured to be able to form images on both sides of the paper P. The control unit 260, which is a control device of the image forming system, performs an adjustment operation when one of the upstream device 200 and the downstream device 300 is performing an adjustment operation when executing a job including double-sided printing. A mode in which a job is executed by double-sided printing processing of the other image forming apparatus that has not been performed, and after the adjustment operation of one image forming apparatus is completed, the job is executed by serial double-sided printing processing (tandem mode) Has moved to.

  According to this configuration, as shown in FIG. 5, when one of the upstream machine 200 and the downstream machine 300 is performing the adjustment operation, the other image forming apparatus that is not performing the adjustment operation is a single-sided surface. A job can be executed by printing processing. Therefore, the job can be started in advance in the other image forming apparatus that is operating without waiting for the state in which both the upstream apparatus 200 and the downstream apparatus 300 operate normally. Further, the image forming apparatus during the adjustment operation can autonomously return to an operation state in which image formation is possible after the adjustment operation is completed. As a result, after that, jobs can be executed by serial double-sided printing processing, so that productivity can be improved compared to the case where single-sided double-sided printing processing is continued. . Therefore, it is possible to execute a job including double-sided printing as quickly as possible while avoiding the influence of the adjustment operation of the image forming apparatus, and to reduce system downtime. In the figure, T1 indicates the timing when the adjustment operation of one image forming apparatus is completed, and T2 indicates the timing when the adjustment operation of the other image forming apparatus is completed (the same applies to FIG. 6 described later). ).

  In this embodiment, when the adjustment operation of one image forming apparatus is completed prior to the end of the job by the single-sided double-sided printing process, the control unit 260 synchronizes with the completion of the tandem mode. Thus, the remaining part of the printing for the job is executed by serial double-sided printing processing.

  According to such a configuration, when the adjustment operation of one of the image forming apparatuses is completed, it is possible to switch from the single-sided double-sided printing process to the serial double-sided printing process. be able to. As a result, as shown in FIG. 6, the job execution period can be shortened (reduction of time ΔT) as compared to the case where the single-sided double-sided printing process is applied to all the printing related to the job. Thereby, the productivity of the image forming system can be improved.

  In this embodiment, when both the upstream machine 200 and the downstream machine 300 are performing the adjustment operation, the control unit 260 waits until one of the image forming apparatuses completes the adjustment operation, and then performs the job. Trying to do.

  Although the upstream machine 200 and the downstream machine 300 are image forming apparatuses having the same mechanical configuration, the periods required for the adjustment operation tend not to coincide with each other depending on individual differences or differences in the usage frequency of the apparatuses. Therefore, even when both the upstream machine 200 and the downstream machine 300 are instructed to perform the adjustment operation, a situation may occur in which the adjustment operation is terminated by either one of them preceding. In this regard, according to the present embodiment, the job is started in advance in one image forming apparatus for which the adjustment operation has been completed without waiting for the state in which both the upstream machine 200 and the downstream machine 300 operate normally. Can do. Accordingly, it is possible to execute a job including double-sided printing as quickly as possible while avoiding the influence of the adjustment operation of the image forming apparatus, and to reduce system downtime.

  Further, in the present embodiment, the control unit 260 recognizes the boundary between the paper P1 on which an image is formed by a single-sided double-sided printing process and the paper P2 on which an image is formed by a double-sided printing process in series. The paper discharge device 400 is controlled.

  Due to individual differences of individual image forming devices, there is a slight difference in appearance between the printed material obtained by the single-sided double-sided printing process and the printed material obtained by the serial double-sided printing process. There is. According to the present embodiment, since the boundary of the paper P corresponding to the switching of processing can be explicitly shown, such a boundary can be presented to the user. As a result, the print quality can be easily managed, so that the user-friendliness can be improved.

  In this embodiment, the mode is shifted to the tandem mode in synchronization with the completion of the adjustment operation of one image forming apparatus. However, it is only necessary to shift to the tandem mode after the adjustment operation of one of the image forming apparatuses is completed, and the mode may be shifted to the tandem mode after the job being executed is completed. In this embodiment, a job for printing only one copy of a series of printed materials has been described. However, the present invention can also be applied to a job for printing a series of printed materials over a plurality of copies. In this case, the printing may be shifted to the tandem mode after the printing for the predetermined part being executed is completed. Thereby, the quality of the series of printed materials can be improved.

(Second Embodiment)
The image forming system according to the second embodiment will be described below. The second embodiment is different from that of the first embodiment in that the setting to the tandem mode is determined in accordance with the remaining printing for the job. In the following description, descriptions of configurations and operations that are the same as those in the first embodiment will be omitted, and differences will be mainly described.

  FIG. 7 is a flowchart showing an operation procedure of the image forming system according to the second embodiment, and in particular, a flowchart showing details of the printing process in step 10. In this embodiment, unlike the method shown in the first embodiment, a process of a new step is added between steps 16 and 17 and the process.

  Specifically, in step 19 (S19) following the affirmative determination of step 16, the control unit 260 determines whether or not the determination parameter exceeds a reference value. Here, the determination parameter is a value related to the remaining print portion of the job when the adjustment operation for the other image forming apparatus is completed, and (1) the remaining number of pages, (2) the remaining print time, and the like. This is the case.

  For example, as shown in FIG. 8, in a scene where a large number of pages are printed, when the adjustment operation of the other image forming apparatus is completed, there may be a small amount of print remainder. In this case, there is not much difference between the job execution period obtained by performing duplex printing with the tandem mode set and the job execution period obtained by continuing the single-sided duplex printing process. is there. Therefore, in such a scene, even if the adjustment operation of the other image forming apparatus is completed, it is possible to continue the double-sided printing process alone until the end of the job without setting the tandem mode. The aforementioned judgment may be provided.

  The reference values to be compared with the judgment parameters are the productivity obtained by ending the job by continuing the single-sided double-sided printing process, and the two-sided printing by setting the tandem mode after the adjustment operation is completed. The optimum value is set through experiments and simulations as a value that can sufficiently exhibit the latter effect in consideration of the obtained productivity. For example, when the determination parameter is set as the remaining number of pages, a value of the printing capability (ppm) of the upstream machine 200 or the downstream machine 300 is used as the reference value, or the determination parameter is set as the remaining printing time. If it is set, 1 minute is used as the reference value.

  If an affirmative determination is made in step 19, that is, if the determination parameter is larger than the reference value, the process proceeds to step 17. On the other hand, if a negative determination is made in step 19, that is, if the determination parameter is equal to or less than the reference value, the process proceeds to step 20 (S20).

  In step 20, the control unit 260 performs standby processing. This standby process waits until the job is completed by continuing the single-sided double-sided printing process, and the standby time is set according to the above-described determination parameter. Then, after this standby process is completed, the process proceeds to step 17.

  As described above, in the present exemplary embodiment, when the adjustment operation of one image forming apparatus is completed, the control unit 260 determines whether or not to shift to the tandem mode based on the remaining portion of the printing related to the job. .

  According to such a configuration, in a scene where there is no significant difference in job execution time between single-sided double-sided printing processing and serial double-sided printing processing, serial double-sided printing corresponding to the end of the adjustment operation Switching to processing can be delayed. Therefore, since the single-sided double-sided printing process can be continued, all the printing related to the job can be finished by the single-sided double-sided printing process. As a result, in a series of printed materials for a job, a printed material obtained by single-sided double-sided printing processing and a printed material obtained by serial double-sided printing processing are mixed, and an apparent difference appears between the two. It is possible to suppress the occurrence of such a situation.

  In the present embodiment, a job for printing only one copy of a series of printed materials has been described. However, the present invention can also be applied to a job for printing a series of printed materials over a plurality of copies. In this case, the aforementioned determination parameter may be the remaining number of faces up to the boundary between the most recent copies, or the remaining printing time.

  The image forming system according to the embodiment of the present invention has been described above, but the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications are possible within the scope of the invention. . For example, in the serial tandem type image forming system of the present invention, the image forming apparatus as the upstream machine and the downstream machine may be an image forming apparatus that employs a system other than the electrophotographic system.

  Further, the upstream machine and the downstream machine may be connected in series by interposing a relay device for reversing the front and back of the paper between the upstream machine and the downstream machine. In this case, when a job is executed by serial double-sided printing processing, the paper may be reversed by a relay device. Further, if the image forming system includes such a relay device, the upstream machine and the downstream machine do not need to have the reverse paper discharge function. Further, the upstream machine and the downstream machine do not have to have the same configuration in a strict sense, and it is sufficient if each of them is configured to be able to execute a single-sided double-sided printing process.

  In the above-described embodiment, the control unit of the upstream machine is responsible for the function of the control device in the image forming system. However, the control unit of any device including the control unit may replace the dedicated function. A control device may be provided independently, and this may be realized.

  Further, in the above-described embodiment, when the sheet is conveyed by relaying the image forming apparatus in the adjustment operation, the image forming conveyance path is used, but the present invention is not limited to this. . For example, a bypass path different from the conveyance path for image formation may be provided in the upstream machine and the downstream machine, thereby relaying the paper.

DESCRIPTION OF SYMBOLS 100 Large-capacity paper feeder 110 Paper feed part 200 Upstream machine 230 Image formation part 231 Photosensitive drum 232 Development unit 240 Fixing part 250 Conveyance part 260 Control part 300 Downstream machine 330 Image formation part 340 Fixing part 350 Conveyance part 360 Control part 400 Paper output device 410 Paper output tray

Claims (6)

A first image forming apparatus that forms an image on one side or both sides of a sheet;
The second image forming apparatus is connected in series with the first image forming apparatus so as to be able to receive a sheet discharged from the first image forming apparatus, and forms an image on one side or both sides of the sheet. An image forming apparatus;
A control device that controls each of the first image forming apparatus and the second image forming apparatus according to a job,
The control device executes an adjustment operation in which one of the first image forming device and the second image forming device adjusts the performance related to image formation when executing a job including double-sided printing. In this case, the other image forming apparatus that has not performed the adjustment operation executes the job by the first double-sided printing process in which images are formed on both sides of the paper,
After the adjustment operation of the one image forming apparatus is completed, the first image forming apparatus forms an image on one side of the sheet, and the second image forming apparatus forms an image on the other side of the sheet. An image forming system that shifts to a mode in which a job is executed by the second double-sided printing process.   When the adjustment operation of the one image forming apparatus is completed prior to the end of the job by the first double-sided printing process, the control device prints the job by the second double-sided printing process. The image forming system according to claim 1, wherein the remaining part of the image forming apparatus is executed.   When both the first image forming apparatus and the second image forming apparatus are performing the adjustment operation, the control device waits until one image forming apparatus completes the adjustment operation. 3. The image forming system according to claim 1, wherein a job is executed.   When the adjustment operation of the one image forming apparatus is completed, the control device determines whether or not to shift to a mode in which the job is executed by the second double-sided printing process based on the remaining print portion of the job. 4. The image forming system according to claim 1, wherein the determination is made. A paper discharge device that is connected in series with the second image forming device, receives paper discharged from the second image forming device, and discharges the paper onto a paper discharge tray;
The control device controls the paper discharge device so that a boundary between a paper on which an image is formed by the first double-sided printing process and a paper on which an image is formed by the second double-sided printing process is understood. The image forming system according to claim 1, wherein the image forming system is an image forming system. A first image forming apparatus that forms an image on one side or both sides of a sheet;
The second image forming apparatus is connected in series with the first image forming apparatus so as to be able to receive a sheet discharged from the first image forming apparatus, and forms an image on one side or both sides of the sheet. In a control method of an image forming system having an image forming apparatus,
A first step of acquiring a job including double-sided printing during a period in which one of the first image forming apparatus and the second image forming apparatus is performing an adjustment operation for adjusting performance relating to image formation;
A second step of executing a job by a first double-sided printing process in which the other image forming apparatus not performing the adjustment operation forms an image on both sides of the paper;
After the adjustment operation of the one image forming apparatus is completed, the first image forming apparatus forms an image on one side of the sheet, and the second image forming apparatus forms an image on the other side of the sheet. A third step of shifting to a mode for executing a job by the second double-sided printing process;
An image forming system control method comprising:

Images