Image forming system, method for controlling the image forming system, and program

Abstract

To provide an image formation system which can form an image properly adjusted to a first surface and a second surface of a sheet.SOLUTION: An image formation system comprises: means which performs image formation on a first surface by using an adjustment value of the first surface and performs image formation on a second surface by using an adjustment value of the second surface; means which acquires update information of the first surface and update information of the second surface during processing of a series of image formation for forming images on plural sheets; and means which updates the adjustment value of the first surface based on the update information of the first surface according to the acquisition and then updates the adjustment value of the second surface according to the satisfaction of a prescribed condition.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to picture an image forming system , a method for controlling an image forming system, and a program and is related thereto.

Background Art

[0002] A printing system is known in which a reading device is connected to the subsequent stage of an image forming apparatus that forms an image on paper, and the image on the paper formed by the image forming apparatus is read by the reading device. In Patent Document 1, a technique is disclosed in which a chart is read during a series of image formations and then adjustments are made for subsequent image formations. In such a configuration, the adjustment content is updated each time an opportunity for image adjustment occurs.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a general image forming system, first, an image is formed on the surface of the fed paper by an image forming unit, the paper is reversed in the conveyance path and then conveyed to the image forming unit again, and an image is formed on the back surface and output. Therefore, when performing double-sided printing continuously, depending on the length of the conveyance path of the apparatus, the image formation on the front surface precedes the image formation on the back surface. Therefore, assuming that the adjustment value is updated at a certain timing as in Patent Document 1 and applied to the image formation on the front surface and the image formation on the back surface. Then, a situation may occur where the adjustment value before the update is applied to the front surface where the image is formed at an early timing, and the adjustment value after the update is applied to the back surface where the image is formed at a late timing. Since the product with adjustment values applied at different timings on the back surface and the front surface may give the customer a sense of discomfort, it is desirable that the adjustment values at the same timing be applied to the back surface and the front surface.

[0005] The objective of the present invention is, Without interrupting the series of image formation processes, The objective is to provide a mechanism that can form images appropriately adjusted for the first and second surfaces of a sheet. [Means for solving the problem]

[0006] The present invention relates to an image forming system in which an Nth sheet, on which an image has been formed on the first surface in an image forming unit, is circulated to the image forming unit as a sheet to be image formed after the N+i sheets that follow the first sheet, and an image is formed on the second surface of the Nth sheet, wherein the reading means reads the sheet after the image has been formed in the image forming unit, and during a series of image forming processes in which images are formed on multiple sheets, the reading means reads the multiple sheets during the series of image forming processes of The present invention is characterized by comprising: an acquisition means that acquires, based on the sheet reading results, a second adjustment value updated from a first adjustment value for the first surface and a fourth adjustment value updated from a third adjustment value for the second surface as adjustment values ​​to be used for image formation; and a control means that processes the updated second adjustment value for the first surface and the unupdated third adjustment value for the second surface to be simultaneously stored in the storage unit during a portion of the series of image formation processes, and controls the image forming unit to form an image on the first surface of the N+i sheet using the updated second adjustment value for the first surface without interrupting the series of image formation processes, and then to form an image on the second surface of the N sheet using the unupdated third adjustment value for the second surface. [Effects of the Invention]

[0007] According to the present invention, without interrupting a series of image formation processes 、 It is possible to form images that are appropriately adjusted for the first and second surfaces of the sheet. [Brief explanation of the drawing]

[0008] [Figure 1]Figure 1(a) is a block diagram showing the system configuration of an MFP. Figure 1(b) is a block diagram showing the system configuration of a printer. Figure 1(c) is a block diagram showing the system configuration of a reader. [Figure 2] Figure 2(a) is a cross-sectional view showing the mechanical configuration of the MFP, reader, and finisher. Figure 2(b) is a diagram illustrating the configuration of the reader. [Figure 3] Figure 3(a) shows a sheet with an adjustment chart formed on it. Figure 3(b) is a diagram illustrating the adjustment chart. Figure 3(c) shows examples of each dimension in the adjustment chart. [Figure 4] Figure 4(a) shows the method for calculating the position adjustment value. Figure 4(b) shows an example of the adjustment value set before and after the update. [Figure 5] This diagram shows a management table for paper types and adjustment value IDs. [Figure 6] This diagram shows the relationship between the sheet transport order and the adjustment values. [Figure 7] Figure 7(a) is a flowchart showing the process of registering adjustment values. Figure 7(b) is a flowchart showing the process of reflecting adjustment values. [Figure 8] Figure 8(a) is a diagram showing the sequence of image formation processing steps. Figure 8(b) is a diagram showing the image adjustment settings screen. [Figure 9] Figure 9 is a flowchart illustrating the control of how adjustment values ​​are reflected during printing. [Figure 10] This diagram shows the control of updating the adjustment value using a flowchart. [Figure 11] Figure 11(a) is a flowchart showing the control of the reader. Figure 11(b) is a flowchart showing the control of the adjustment value update. [Figure 12] This diagram shows the relationship between the sheet transport order and the adjustment values. [Figure 13] This diagram shows a flowchart illustrating the control of how adjustment values ​​are reflected during printing. [Figure 14] This diagram shows a management table for paper types and adjustment value IDs. [Figure 15] It is a diagram showing the relationship between the sheet conveyance order and the adjustment value. [Figure 16] FIG. 16(a) is a diagram showing the transmission control of the reading result in a flowchart. FIG. 16(b) is a diagram showing the reflection control of the adjustment value in a flowchart. [Figure 17] FIG. 17 is a diagram showing the sequence of the series of image forming processes. [Figure 18] It is a diagram for explaining the circulation conveyance.

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments for carrying out the present invention will be described with examples and specifically explained using the drawings.

[0010] (Example 1) <Image Forming System> FIG. 2(a) is a mechanical cross-sectional view of the image forming system. As shown in FIG. 2(a), the image forming system is configured by connecting the MFP 100, the reading device 400, and the finisher 109. The MFP 100 is an image forming device that forms an image on a sheet. The image forming method of the MFP may be any of an electrophotographic method, an inkjet method, and other methods. Here, it will be described as an electrophotographic image forming device. The reading device 400 is an optional device that reads an image from the sheet (original) on which the image has been formed and can be connected to the subsequent stage of the MFP. The finisher 109 is a post-processing device that performs post-processing on the sheet on which the image has been formed. The image forming system outputs the sheet on which the image has been formed as a product by conveying the sheet (paper) in the order of the MFP 100, the reading device 400, and the finisher 109. The series of processes of image formation will be described.

[0011] The MFP100 is equipped with paper feed decks 301 and 302, which can accommodate various types of paper. Each paper feed deck can separate only the top sheet of paper stored and transport it to the paper transport path 303. Developing stations 304 to 307 use colored toners Y, M, C, and K respectively to form a toner image for creating a color image. The toner image formed here is first transferred to an intermediate transfer belt 308 and transported to a secondary transfer position 309 by the clockwise rotating intermediate transfer belt 308. The toner image is then transferred to the paper transported from the paper transport path 303. The fuser unit 311 is configured to fix the toner image to the paper. The fuser unit 311 is equipped with a pressure roller and a heating roller, and as the paper passes between the rollers, the toner is melted and pressed, fixing the toner image onto the paper (sheet). The paper that has passed through the fuser unit 311 is transported through the paper transport path 312 to the paper transport path 315. If the type of paper requires further melting and pressing for fixing, after passing through the fixing unit 311, it is transported to the second fixing unit 313 using the paper transport path above. After additional melting and pressing, it is transported to the paper transport path 315 via the paper transport path 314. If the image formation mode is double-sided, the paper is transported to the paper inversion path 316, and after inversion, it is transported to the double-sided transport path 317, where the second image transfer is performed at the secondary transfer position 309. In this case, the image formation of the second side is performed sequentially so as to follow the other sheets that were following during the image formation of the first side. This method of transporting paper is called circular transport.

[0012] Figure 18 shows the flow of paper in a circular transport system. Figure 18 shows the progress of the circular transport system in three stages. Here, the paper number indicates the order in which the paper was supplied for image formation, and the page number indicates the order in which image formation is performed. The paper number is the same for both the front and back sides, while the page number is different for the front and back sides.

[0013] In the state shown in the upper section, paper sheets numbered 1 through 7 are present in the MFP100. At this stage, only the surface image has been formed, so the paper number and page number correspond to each other.

[0014] In the state shown in the middle section, there are sheets of paper numbered 1 through 8 inside the MFP100. At this time, the back side of sheet number 1 is processed as page number 8, and the back side of sheet number 2 is processed as page number 10. In other words, image formation for pages 8, 9, and 10 is processed in the order of back side, front side, back side. Thus, in circular transport, image formation for the front side and image formation for the back side are processed together.

[0015] In the state shown in the lower section, paper numbers 4 to 13 are present in the MFP100. At this time, paper numbers 1, 2, and 3, for which the image formation on the reverse side has been completed, are being transported to the reader 400 in order.

[0016] The paper transported to the reader 400 is transported along the paper transport path 323, passing through the reading positions of the upper reading unit 321 (front-side CIS unit) and the lower reading unit 322 (back-side CIS unit). If the transported paper is an image adjustment chart paper with only an image adjustment pattern printed on it (for example, the chart 900 described later), the flapper 324 is switched to transport the paper to the discharge path 326. The paper (output, printed material) transported to the discharge path 326 is discharged to the discharge tray 328. If the paper transported to the paper transport path 323 contains a user's print image (for example, the chart 901 described later), the flapper 324 is switched to transport the paper to the downstream transport path 325. The paper transported to the downstream transport path 325 is transported to the finisher 109. If the finisher 109 notifies that a transport jam has occurred, it switches the flapper 324 to transport paper to the discharge path 326, even if it is not image adjustment chart paper, and discharges it to the discharge tray 328. Discharging all remaining paper to the discharge tray 328 reduces the user's jam handling burden. The finisher 109 is a paper discharge unit capable of loading a large amount of paper. The finisher has a stack tray 332 as a tray for loading paper. Paper transported from the printing device 107 is loaded into the stack tray 332 via the paper transport path 331. The finisher 109 detects the passage of paper with transport sensors 334, 335, and 336. If the leading or trailing end of the paper does not reach the tray after a predetermined time has elapsed, it determines that a transport jam has occurred in the finisher 109 and notifies the MFP 100 that a transport jam has occurred.

[0017] <mfp> The configuration of the MFP100 will now be described. Figure 1(a) is a system block diagram of the MFP100 used as an image forming apparatus. As shown in Figure 1(a), the MFP100 comprises a control unit 110, a scanner 130, a printer 140, and an operation unit 150.

[0018] The scanner 130 is a reading unit that reads an image from the original document. The scanner 130 can be either an ADF type, a pressure plate type, or both.

[0019] The printer 140 is an image forming unit that forms an image on a sheet.

[0020] The operation unit 150 is an operation panel that displays information to the user and accepts input from the user. The operation unit 150 includes a display unit for displaying information and hard keys for receiving information input. Alternatively, the operation unit 150 may also use a touch panel that supports information input and output.

[0021] The control unit 110 is a controller that comprehensively controls the MFP 100. The control unit 110 is connected to the scanner 130, which is an image input device, and the printer 140, which is an image output device, and controls the input and output of image information. On the other hand, the control unit 110 is also connected to a LAN and receives print jobs via it. The control unit 110 includes a CPU 111, RAM 112, ROM 113, storage unit 114, network interface 115, device interface 116, operation interface 117, image processing unit 118, and image memory 119.

[0022] The CPU 111 controls the operation of the MFP 100 and operates based on a program stored in the RAM 112. The ROM 113 is the boot ROM and stores the system's boot program. The storage unit 114 stores system software, image data, and programs for controlling the operation of the MFP 100. An HDD or SSD is used as the storage unit. The program stored in the storage unit 114 is loaded into the RAM 112, and the CPU 111 controls the operation of the MFP 100 based on this. The network interface 115 is connected to the LAN and handles the input and output of various information via the network. The device interface 116 connects the control unit 110 to image input / output devices such as the scanner 130 and printer 140, and performs synchronous / asynchronous conversion of image data. The printer 140 can also be connected to various accessories such as the finisher 109 and the reader 400. The operation unit interface 117 is an interface that connects the operation unit 150 and the control unit 110, and outputs image data for display on the operation unit 150 to the operation unit 150. Furthermore, the operation unit I / F 117 transmits information entered by the user from the operation unit 150 to the CPU 111. The image processing unit 118 is a processor that performs image processing on print data received via LAN. The image processing unit 118 also performs image processing on image data input and output from the device I / F 116. The image memory 119 is a memory for temporarily expanding the image data processed by the image processing unit 118.

[0023] Figure 1(b) is a block diagram of the printer 140. The printer 140, which is an image forming unit that forms an image on a sheet, has a configuration that includes a printer control unit 210 and an image output unit 230. The printer control unit 210 includes a CPU 211, ROM 213, RAM 212, storage unit 214, device I / F 215, engine control unit 216, and image processing unit 217. The CPU 211 controls the operation of the printer 140 and operates based on a program stored in the ROM 213 and expanded in the RAM 212. The storage unit 214 stores information necessary for controlling the printer control unit 210, as well as programs for controlling the operation of the printer 140. The device I / F 215 is connected to the control unit 110 and performs synchronous / asynchronous conversion of image data. The engine control unit 216 controls each part of the printer engine, such as the image output unit 230, finisher 109, and reader 400, and connected accessories. The image processing unit 217 processes the image data to be output to the image output unit 230.

[0024] <Reading device> Figure 1(c) is a block diagram of the reading device 400. The reading device 400 comprises a reading device control unit 410, an upper reading unit 321, and a lower reading unit 322. The reading device control unit 410 comprises a CPU 411, ROM 413, RAM 412, storage unit 414, I / F unit 415, image reading control unit 416, and image analysis unit 417.

[0025] The CPU 411 controls the operation of the reader 400 and operates based on a program stored in the ROM 413 and loaded into the RAM 412. The memory unit 414 stores information necessary for controlling the reader 400, as well as programs for controlling the operation of the reader 400. The I / F unit 415 connects to the printer control unit 210 and exchanges information such as the analysis results of the image data read by the reader. The image reading control unit 416 controls the top reading unit 321 and the bottom reading unit 322. The image analysis unit 417 analyzes the images read by the top reading unit 321 and the bottom reading unit 322.

[0026] As shown in Figure 2(b), the top reading unit 321 is a CIS (Contact Image Sensor) unit for reading the top surface of the paper, and the bottom reading unit 322 is a CIS (Contact Image Sensor) unit for reading the bottom surface of the paper. When the paper transported on the paper transport path 323 reaches a predetermined position, if there is an image adjustment pattern on the transported paper, the top reading unit 321 and the bottom reading unit 322 are used to read the image. Note that the CIS unit may also be other optical sensors such as a CCD image sensor or a CMOS image sensor. The read information is stored in the storage unit 414, and the image analysis unit 417 analyzes it and feeds it back into the image formation conditions to adjust (correct) the image position. When the internal temperature of the MFP100 rises, the position of the image formed on the paper changes compared to when the internal temperature of the MFP100 is low. The amount of change is obtained by reading the image adjustment pattern with the CIS unit, and the image position is adjusted based on the obtained amount of change so that it is printed in the same position as when the internal temperature is low. This stabilizes the image position accuracy. In addition to adjusting the image position, you may also adjust the image density and other parameters.

[0027] <Usage Sequence> Figure 8(a) shows the sequence when a user submits a job, and during the process, image adjustments are made, and then printing is performed using the adjustment results. In S801, the user submits a print job. At this time, it is assumed that the job is submitted with the setting to perform image adjustments in real time, as shown in Figure 8(b). In S802, the image processing unit 118 processes the image sequentially and transfers the image to the image output unit 230. The image output unit 230 transports the paper sequentially to the next stage, starting with the paper that has been printed on the back side. In S803, the image reading control unit 416 reads the image of the transported paper, and the image analysis unit 417 performs the analysis. The read paper is sequentially transported to the stack tray 332. After the image analysis unit 417 has performed image analysis on a predetermined number of sheets (the figure shows an example of 3 sheets), it provides feedback to the image processing unit 118 in S804. In S805, the image processing unit 118 updates the adjustment values ​​in the storage unit 114 based on the received feedback and stores them. Repeating the above process until all the paper has been transported to the stack tray 332, the user can retrieve the output using S806.

[0028] <Chart> This section explains the image reading process described in S806. Figures 3 and 4 illustrate the image position adjustment.

[0029] Figure 3 is a diagram illustrating the image read by the reader 400 and the measurements obtained by analyzing that image. Chart 900 shown in Figure 3(a) is an example of an image position adjustment chart, schematically representing a sheet of paper with marks for image position adjustment printed on it. Chart 901 is an example in which an image position adjustment chart is overwritten on the margin (edge ​​of the sheet) of the user's printed image. The gray area 905 in the figure represents the portion of the user's printed image. The reader 400 can perform the measurements described later on either Chart 900 or Chart 901 output (deliverable). The image analysis unit 417 performs measurements on the parts represented by (A) to (J) shown in Figure 3(b). (A) and (B) are the main scanning direction length and sub-scanning direction length of the chart, respectively, and the ideal length is the paper length defined in the paper library. (C) to (J) are the distance from mark 902 to the nearest edge of the paper. Figure 3(c) shows an example of feedback measured by the reader 400 and notified to the control unit 110 via the printer control unit 210. As shown in the table, an adjustment value ID is assigned to the feedback. In addition, since feedback is performed on both the front and back surfaces, the front / back surface information is also provided along with the measured value.

[0030] Figure 4 is a diagram illustrating the calculation of image position adjustment values ​​in the control unit 110 based on feedback received from the reader 400. Figure 4(a) is a summary in Table 910 of the method for calculating the print position misalignment. Item 911 shows how the measured values ​​shown in Figures 4(b) and (c) are handled by formulas. Item 912 represents the ideal value, and item 913 shows how the adjustment value is calculated. The image processing unit 118 calculates the adjustment value for each of the adjustment items 914 to 917 and stores it in the storage unit 114.

[0031] Figure 4(b) is a table summarizing an example of the adjustment values ​​mentioned above. These values ​​were calculated using the calculation method shown in Figure 4(a) based on the feedback shown in Figure 3(c). As shown in the table, the adjustment values ​​for the front and back sides are stored in set 921. The adjustment values ​​are updated based on the feedback independently for the front side item group 922 and the back side item group 923.

[0032] <Feedback timing> Figure 5 illustrates the association between paper and the aforementioned adjustment value ID. As described above, an ID is assigned to the adjustment value, and the printer control unit 210 instructs the control unit 110 to apply the adjustment value ID (described later). The printer control unit 210 maintains a table 500 in the storage unit 214, as shown in Figure 5, which manages which adjustment value ID was instructed for which paper. When forming the image on the front side, the printer control unit 210 registers the paper number and the adjustment value ID instructed to the control unit 110. Next, when forming the image on the back side of the paper, the printer control unit 210 refers to this table, retrieves (determines and confirms) the adjustment value ID instructed when forming the image on the front side, and instructs the control unit 110. The control unit 110 retrieves the set of adjustment values ​​corresponding to the adjustment value ID instructed by the printer control unit 210 from the storage unit 114, and processes the image in the image processing unit 118. In this way, the same adjustment value ID is used to form images on both the front and back sides of the same paper.

[0033] Figure 6 schematically represents the sequence for updating image adjustment values ​​while performing continuous double-sided printing (a series of image formations). As shown in process 601, the printer control unit 210 instructs the control unit 110 to provide an adjustment value ID before generating an image on each page, and registers the instructed adjustment value ID in the management table shown in Figure 5. The image processing unit 118 of the control unit 110, upon receiving the instruction, references the set of adjustment values ​​from the storage unit 114 according to the instruction, as shown in process 602, and performs image processing. Adjustment value sets 610 and 611 schematically represent the first set of adjustment values ​​(921) and the second set of adjustment values ​​(922) shown in Figure 4(b), respectively. At the beginning of the sequence in Figure 6, only adjustment value set 610 is assigned adjustment value ID:1, and the image processing unit 118 performs image processing by referring to adjustment value set 610 (the first set of adjustment values). In processes 603 and 604, the printer control unit 210 provides feedback to the control unit 110 with adjustment value ID:2, and the image processing unit 118 of the control unit 110 calculates the adjustment value and stores it in the storage unit 114. At this time, the second set of adjustment values ​​shown in adjustment value set 612 is updated, and in the figure, this indicates that adjustment value ID:2 has been assigned. Before the image of the front surface is generated after the feedback in processes 603 and 604, the printer control unit 210 issues an instruction for the latest adjustment value ID (process 605). Before the image of the back surface is generated, the printer control unit 210 refers to the table shown in Figure 5 and retrieves and issues the adjustment value ID that was issued before the image of the front surface was generated (process 606).

[0034] <Control Flow> Figure 7 shows the flow of processing performed by the printer control unit 210 and the image processing unit 118. Figure 7(a) shows the processing of the printer control unit at the start of image processing. In this process, the program stored in the ROM 213 is loaded into the RAM 212 and executed by the CPU 211. In S701, the CPU 211 receives a paper feed start instruction from the control unit 110. In S702, the CPU 211 determines whether the printing side is the front side. If it is the front side (S702 YES), the CPU 211 notifies the control unit 110 of the latest adjustment value ID in S703 and registers the notified adjustment value ID in S704. If it is the back side (S702 NO), the CPU 211 refers to the table stored in the memory unit 214 in S705 and retrieves the adjustment value ID for the paper. Subsequently, in S706, the CPU 211 notifies the control unit 110 of the retrieved adjustment value ID.

[0035] Figure 7(b) shows the flow of image processing performed by the image processing unit 118. In this process, a program stored in the ROM 113 is loaded into the RAM 112 and executed by the CPU 111. The CPU 111 receives an image generation instruction in S721. Next, in S722, the CPU 111 receives an instruction from the printer control unit 210 for an adjustment value ID to be applied to the image processing. Subsequently, in S723, the CPU 111 generates an image based on the received adjustment value ID.

[0036] Figure 10 shows the flow of updating the adjustment value. In this process, the program stored in ROM 113 is loaded into RAM 112 and executed by CPU 111. CPU 111 receives feedback from the printer control unit 210 in S1001 (for example, processes 603 and 604 shown in Figure 6). Next, CPU 111 calculates the adjustment value from the feedback in S1002. CPU 111 obtains the latest adjustment value ID in S1003 and updates the set that is different from the set of the latest adjustment value in S1004. Finally, CPU 111 updates the latest adjustment value ID in S1005 with the adjustment value ID notified by the feedback. In other words, the set that holds the updated adjustment value and the set that holds the adjustment value before the update are swapped in real time. As a result, it is only necessary to maintain a number of adjustment value sets that is less than the total number of updates during the series of processes.

[0037] Figure 9 shows the workflow for determining the appropriate adjustment value ID to be used for image generation in the printer control unit 210 without using the table S705 described in Figure 7. This process is executed by the CPU 211 after the program stored in ROM 213 is loaded into RAM 212. In S901, the CPU 211 obtains the average number of sheets N for the adjustment values ​​input from the operation unit 115. The average number of sheets N is set to how many sheets of paper adjustment is performed in real time, as shown in Figure 8(b). In S902, the CPU 211 calculates the required number of adjustment value sets S. Here, if M is the number of sheets of paper that circulate (are transported) within the machine, which is unique to each model, the number of sets S is expressed by the following formula (1). The decimal point of the calculation result of M / N is truncated.

[0038]

number

[0039] CPU211 retrieves the latest adjustment value ID in S903. CPU211 determines in S904 whether the printed surface is the front. If it is the front (S904YES), CPU211 sets the latest adjustment value ID to the adjustment value ID used for image generation in S905. If it is the back (S904NO), CPU211 determines in S906 whether the latest adjustment value ID has changed after image generation for the corresponding front surface. If the adjustment value ID has been updated (S906YES), CPU211 sets the adjustment value ID used for image generation to the adjustment value ID S-1 prior to the latest adjustment value ID in S907. If the adjustment value ID has not been updated (S906NO), CPU211 sets the latest adjustment value ID to the adjustment value ID used for image generation in S908.

[0040] Figure 11 shows the processing flow of the reading control unit 400 and the printer control unit 210. Figure 11(a) shows the processing flow of the reading device 400, which reads an image adjustment chart and notifies the printer control unit 210 of the measured values. This processing is performed by the CPU 411 after the program stored in the ROM 413 is loaded into the RAM 412. The CPU 411 receives an instruction to read the image in S1101. The CPU 411 reads the image in S1102. The CPU 411 analyzes the image in S1103. The CPU 411 acquires the measured values ​​in S1104. The CPU 411 notifies the image processing unit 118 of the measured values ​​in S1105. Figure 11(b) shows the processing flow of the printer control unit 210, which acquires the measured values ​​(reading results) for an averaged number of N images and updates the adjustment value ID. This processing is performed by the CPU 211 after the program stored in the ROM 213 is loaded into the RAM 212. In S1121, the CPU 211 obtains the average number N of adjustment values ​​input from the operation unit 150. In S1122, the CPU 211 obtains measurement values ​​from the image reading device 400. In S1123, the CPU 211 determines whether N measurement values ​​have been obtained. If N measurement values ​​have been obtained (S1123 YES), the CPU 211 updates the adjustment value ID and adjustment value in S1124. At this time, the adjustment value ID is set to the current adjustment value ID incremented. However, the adjustment value ID is limited to S, and becomes 1 when it reaches S+1. The adjustment value is the average of the obtained measurement values. If N measurement values ​​have not been obtained (S1123 NO), the CPU 211 terminates processing.

[0041] <Remarks> As explained above, according to this embodiment, during a certain period of the image formation process, one set of adjustment values ​​can be used to adjust the image on the first side (front) of the sheet, and the other set of adjustment values ​​can be used to adjust the image on the second side (back) of the sheet. Therefore, regardless of the timing of the adjustment value updates, the image adjustments can be appropriately reflected on both the front and back sides.

[0042] (Example 2) The system of Example 2 is configured similarly to the system of Example 1, except for some characteristic components. Therefore, the same reference numerals are used for similar components, and their detailed descriptions are omitted.

[0043] In Embodiment 2, the control unit 110 maintains a table 500 in the storage unit 114, as shown in Figure 5, which manages which adjustment value ID was instructed for which paper. When forming the image on the front side, the control unit 110 registers the paper number and the adjustment value ID applied by the image processing unit 118. Next, when forming the image on the back side of the paper, the control unit 110 refers to this table, retrieves (determines and confirms) the adjustment value ID instructed when forming the image on the front side, and applies it to the image processing unit 118 to process the image. In this way, the same adjustment value ID is used to form images on both the front and back sides of the same paper.

[0044] <Feedback timing> Figure 6 schematically represents the sequence of updating image adjustment values ​​while performing continuous double-sided printing (a series of image formations). The image processing unit 118 determines the adjustment value ID to be applied to the image processing of each page, as in process 1601, and then references the set of adjustment values ​​from the storage unit 114 according to the result and performs image processing. Adjustment value sets 1610 and 1611 schematically represent the first set of adjustment values ​​(921) and the second set of adjustment values ​​(922) shown in Figure 4(b), respectively. At the beginning of the sequence in Figure 6, only adjustment value set 1610 is assigned adjustment value ID:1, and the image processing unit 118 performs image processing by referring to adjustment value set 1610 (the first set of adjustment values). In processes 1602 and 1603, the printer control unit 210 provides feedback of adjustment value ID:2 to the control unit 110. The control unit 110 calculates the adjustment value in the image processing unit 118 and stores it in the storage unit 114 (process 1604). At this time, the second set of adjustment values ​​shown in adjustment value set 1612 is updated, and the figure shows that adjustment value ID:2 has been assigned. For the image processing of the surface after feedback from processes 1602 and 1603, the image processing unit 118 applies the latest adjustment value ID (process 1605). For the image processing of the back surface, the image processing unit 118 refers to the table shown in Figure 5 and calls up and applies the adjustment value ID that was referenced before the image generation of the surface (process 1606).

[0045] <Control Flow> Figure 7 shows the flow of processing performed by the image processing unit 118. This processing involves the program stored in the ROM 113 being loaded into the RAM 112 and executed by the CPU 111. In S1701, the CPU 111 receives an image processing instruction from the control unit 110. In S1702, the CPU 111 determines whether the printed surface is the front side. If it is the front side (S1702 YES), in S1703, the CPU 111 applies the set of adjustment values ​​for the latest adjustment value ID and performs image processing in the image processing unit 118, and in S1704, registers the applied adjustment value ID. If it is the back side (S1702 NO), in S1705, the CPU 111 refers to the table stored in the memory unit 114 and retrieves the adjustment value ID for the paper. Subsequently, in S1706, the CPU 111 applies the set of adjustment values ​​for the retrieved adjustment value ID and performs image processing in the image processing unit 118.

[0046] Figure 10 shows the flow of updating the adjustment value. In this process, the program stored in ROM 113 is loaded into RAM 112 and executed by CPU 111. CPU 111 receives feedback from the printer control unit 210 in S1001 (for example, processes 1602 and 1603 shown in Figure 6). Next, CPU 111 calculates the adjustment value from the feedback in S1002. CPU 111 obtains the latest adjustment value ID in S1003 and updates the set that is different from the set of the latest adjustment value in S1004. In other words, the set that holds the updated adjustment value and the set that holds the adjustment value before the update are swapped as needed. As a result, it is only necessary to maintain a number of adjustment value sets that is less than the total number of updates during the series of processes. Finally, CPU 111 updates the latest adjustment value ID in S1005 with the adjustment value ID notified by the feedback.

[0047] Figure 9 shows the flow of the process in the image processing unit 118 for determining the appropriate adjustment value ID to be used for image generation without using the table S1705 described in Figure 7. This process is executed by the CPU 111 after the program stored in the ROM 113 is loaded into the RAM 112. In S901, the CPU 111 obtains the average number of sheets N for which the adjustment values ​​input from the operation unit 150 are averaged. The average number of sheets N is set to how many sheets of paper are adjusted every in real time, as shown in Figure 8(b). In S902, the CPU 111 calculates the required number of adjustment value sets S. Here, if M is the number of sheets of paper that circulate (are transported) within the machine, which is unique to each model, the number of sets S is expressed by equation (1). The decimal point of the calculation result of M / N is truncated.

[0048] CPU111 retrieves the latest adjustment value ID in S903. CPU111 determines in S904 whether the printed surface is the front. If it is the front (S904YES), CPU111 sets the latest adjustment value ID to the adjustment value ID used for image generation in S905. If it is the back (S904NO), CPU111 determines in S906 whether the latest adjustment value ID has changed after image generation for the corresponding front surface. If the adjustment value ID has been updated (S906YES), CPU111 sets the adjustment value ID used for image generation to the adjustment value ID S-1 prior to the latest adjustment value ID in S907. If the adjustment value ID has not been updated (S906NO), CPU111 sets the latest adjustment value ID to the adjustment value ID used for image generation in S908.

[0049] Figure 11 shows the processing flow performed during image formation in the reading device 400 and the image processing unit 118. Figure 11(a) shows the processing flow of the reading device 400, which reads an image adjustment chart and notifies the image processing unit 118 of the measured values. This process is executed by the CPU 411 after the program stored in the ROM 413 is loaded into the RAM 412. The CPU 411 receives an instruction to read the image in S1101. The CPU 411 reads the image in S1102. The CPU 411 analyzes the image in S1103. The CPU 411 acquires the measured values ​​(reading results) in S1104. The CPU 411 notifies the image processing unit 118 of the measured values ​​in S1105. Figure 11(b) shows the processing flow of the image processing unit 118, which acquires measured values ​​for N averaged images and updates the adjustment value ID. This process is executed by the CPU 111 after the program stored in the ROM 113 is loaded into the RAM 112. In S1121, the CPU 111 obtains the average number N of adjustment values ​​input from the operation unit 150. In S1122, the CPU 111 obtains measurement values ​​from the image reading device 400. In S1123, the CPU 111 determines whether N measurement values ​​have been obtained. If N measurement values ​​have been obtained (S1123 YES), the CPU 111 updates the adjustment value ID and adjustment value in S1124. At this time, the adjustment value ID is set to the current adjustment value ID incremented. However, the adjustment value ID is limited to S, and becomes 1 when it reaches S+1. The adjustment value is the average of the obtained measurement values. If N measurement values ​​have not been obtained (S1123 NO), the CPU 111 terminates processing.

[0050] <Remarks> As explained above, according to this embodiment, during a certain period of the image formation process, one set of adjustment values ​​can be used to adjust the image on the first side (front) of the sheet, and the other set of adjustment values ​​can be used to adjust the image on the second side (back) of the sheet. Therefore, regardless of the timing of the adjustment value updates, the image adjustments can be appropriately reflected on both the front and back sides.

[0051] (Example 3) The system of Example 2 is configured similarly to the system of Example 1, except for some characteristic components. Therefore, the same reference numerals are used for similar components, and their detailed descriptions are omitted.

[0052] <Usage Sequence> The usage sequence of the image forming system will now be explained. In this embodiment, during a series of image forming processes in which images are formed sequentially on multiple sheets, the reader 400 reads the sheets in parallel. Then, the content of subsequent image forming is adjusted by feeding back the reading results during the series of image forming processes. In particular, in this embodiment, the timing of the feedback of the reading results is adjusted so that the reading results acquired at the same time are reflected on the front and back sides of the same sheet of paper. This will be explained in detail using Figure 17. For simplicity, in this embodiment, the number of sheets of paper remaining in the MFP 100 will be underestimated when explaining the series of steps.

[0053] Figure 17 shows a sequence of image formation processes in which a user submits a job, and image adjustments are made during the process, followed by printing using the adjusted results. In S801, the user submits a print job. At this time, it is assumed that the job is submitted with the setting to perform real-time image adjustments, as shown in Figure 8(b). In S802, the image processing unit 118 processes the image sequentially and transfers the image to the image output unit 230. The image output unit 230 transports the paper sequentially to the next stage, starting with the paper that has been printed on the back side. In S803, the image reading control unit 416 reads the image of the transported paper, and the image analysis unit 417 performs the analysis. The read paper is sequentially transported to the stack tray 332. During the series of image formation processes, the image analysis unit 417 analyzes a predetermined number of images (the figure shows an example of 3 images) and obtains the feedback value (update information) for the front side and the back side. Then, in S2804, it first provides feedback on the front side to the image processing unit 118. In S2805, the image processing unit 118 stores (sets) the adjustment value in the storage unit 114 to update the adjustment value for the front side based on the received feedback value (update information). The adjustment value updated in S2805 is applied from the front side of the 8th sheet of paper. Therefore, feedback is performed on the back side so that the updated adjustment value is also applied from the 8th sheet of paper. Specifically, after the paper feed instruction for the back side of the 7th sheet (after a predetermined period), feedback for the back side is performed as shown in S2806. At the timing of the feedback for the back side, the image processing unit 118 updates the adjustment value for the back side in S2807 based on the feedback value (update information) and stores (sets) it in the storage unit 114. When the image analysis unit 417 performs image analysis for the next predetermined number of sheets, feedback for the front side is performed in S2808, and the image processing unit 118 updates the adjustment value for the front side in S2809 and stores it in the storage unit 114. In S2810, when processing the last page (the back of the 10th page), it is determined that there are no more pages to process (S2714NO), so the image analysis unit 417 provides feedback on the back side at this time. Based on this feedback, in S2811 the image processing unit 118 updates the adjustment values ​​for the back side and stores them in the storage unit 114. After the image analysis unit 417 has performed image analysis on the next predetermined number of pages, it provides feedback on the front side in S2812.At this point, the printing process is complete (S2704NO), so the image analysis unit 417 also provides feedback on the reverse side in S2813. Once all the paper has been transported to the stack tray 332, the user can acquire the output in S806.

[0054] <Feedback timing> Figure 15 schematically illustrates the sequence of updating image adjustment values ​​while performing continuous double-sided printing.

[0055] The printer control unit 210 receives a paper feed start instruction for each page, as in process 2601. This paper feed instruction notifies the user of, for example, the page number and paper number. The image processing unit 118, as in process 2602, references the adjustment values ​​to be applied to the image processing of each page from the storage unit 114 and performs the image processing. In process 2603, the printer control unit 210 provides feedback to the control unit 110 with the adjustment value ID:2 for the front side. The control unit 110 calculates the adjustment value in the image processing unit 118 and stores it in the storage unit 114 (process 2604). The adjustment value updated at this time is the one shown in item group 922 in Figure 4. The updated adjustment value is applied from the front side of the 8th page. The printer control unit 210 provides feedback of the adjustment value ID:2 for the back side before the image processing of the back side of the 8th page is performed (process 2605). That is, the printer control unit 210 provides feedback of the adjustment value ID:2 for the back side in accordance with the fact that the image processing unit has received a paper feed start instruction after processing the back side image of the 7th page. The control unit 110 calculates the adjustment values ​​in the image processing unit 118 and stores them in the storage unit 114 (processing 2606). The adjustment values ​​updated at this time are those shown in item group 923 in Figure 4.

[0056] Figure 14 illustrates the association between paper and the aforementioned adjustment value ID. As mentioned above, adjustment values ​​are managed by assigning them IDs. The printer control unit 210 maintains a table in the storage unit 214 that manages relationship information such as which adjustment value ID is applied to which paper, as shown in Figure 14. Therefore, when the printer control unit 210 is notified of the paper number from the image processing unit 118, it can manage the adjustment value ID corresponding to the paper number.

[0057] <Control Flow> Figure 16 shows the flow of processing performed by the printer control unit 210. This process involves loading the program stored in the ROM 213 into the RAM 212 and executing it by the CPU 211. Figure 16(a) shows the flow of the read / reflect process.

[0058] The reader control unit 410 sequentially sends the reading results to the printer control unit 210 as soon as it acquires them. The CPU 211 acquires the reading results for both the front and back sides in step S2701. In step S2707, the CPU 211 determines whether it has read a predetermined number of averaged pages. The averaged number of pages here is a value maintained by the system for calculating the average value of the reading results. If it has read the averaged number of pages (S2707 YES), the CPU 211 averages the reading results up to that point in S2708.

[0059] In S2702, CPU211 increments the adjustment value ID counter by 1. In S2703, CPU211 sends the front reading result to the control unit 110. In S2704, CPU211 determines whether or not print-time adjustment is being performed. If print-time adjustment is being performed (S2704YES), in S2705, it stores (updates) the back reading result in the storage unit 214 and prepares for print-time adjustment processing. If CPU211 determines in S2704 that print-time adjustment is not being performed (S2704NO), CPU211 sends the back reading result in S2706 and proceeds with normal adjustment processing. Figure 16(b) shows the flow of the print-time adjustment processing. In S2711, CPU211 receives a page processing start instruction from the control unit 110. This page processing start instruction includes the page number, paper number, front / back information, etc. In S2712, CPU211 determines whether or not the printing surface is the front surface. If the printing surface is determined to be the front surface in S2712 (S2712:YES), the CPU 211 records the paper number and adjustment value ID in the adjustment value table 2500 in S2717. For example, when processing the front surface of paper number 8, the current adjustment value counter is stored in the adjustment value ID column. In this case, since the counter has been updated by 1, "2" is stored in the adjustment value ID.

[0060] If the page to be processed is not the front side, i.e., the back side (S2712: NO), CPU 211 refers to adjustment value table 2500 in S2713 and determines in S2714 whether a subsequent sheet is registered. If a subsequent sheet exists (S2714: YES), CPU 211 determines in S2715 whether the adjustment value ID changes with the next sheet number. If the adjustment value ID changes with the next sheet number (S2715: YES), CPU 211 sends the back side reading result in S2716. For example, if a page processing start instruction for the back side of sheet number 7 is received, the next sheet number will be sheet number 8. At this time, since there is a change in adjustment value ID between sheet numbers 7 and 8, the back side reading result is sent. In other words, CPU 211 determines that it is time to update the adjustment value on the back side if the next sheet for which back side image formation is performed is a sheet that uses the updated adjustment value as the adjustment value for the front side. Similarly, if there is no subsequent paper in S2714 (S2714:NO), CPU211 sends the reading result for the back side in S2716. The adjustment value based on this reading result corresponds to adjustment value ID 3. This adjustment value is not used for image formation this time because there is no subsequent paper, but it can be used for image formation next time. If the adjustment value ID does not change with the next paper number in S2715 (S2715:NO), CPU211 ends the process.

[0061] <Remarks> As explained above, in this embodiment, in a series of image formation processes, after acquiring the reading results for the front and back surfaces, adjustment values ​​are applied to each at different timings. As a result, adjustments based on reading results acquired at the same time are applied to both the front and back surfaces of a single sheet. Therefore, regardless of the timing of acquiring the reading results, adjustment values ​​for image adjustment can be appropriately applied to both the front and back surfaces.

[0062] (Other examples) The present invention can also be realized by supplying a program that implements one or more of the functions of the above-described embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that implements one or more functions.

[0063] Furthermore, the present invention may be applied to a system consisting of multiple devices or to a device consisting of a single device.

[0064] The present invention is not limited to the embodiments described above, and various modifications (including organic combinations of each embodiment) are possible based on the spirit of the invention, and these are not excluded from the scope of the invention. In other words, all configurations that combine the above-described embodiments and their modified forms are included in the present invention.

[0065] Furthermore, while the above embodiment uses the operation unit 150 as an example of setting the adjustment value, other methods may be used for setting it. For example, the setting may be changed from the image processing controller connected to the image forming apparatus. Alternatively, the image forming apparatus may be made to function as a web server and provide a web page to an external device such as a personal computer, so that setting changes can be accepted from an external device running a web browser.

[0066] The abbreviations used in the examples have the following meanings.

[0067] ADF stands for Auto Document Feeder.

[0068] ASIC stands for Application Specific Integrated Circuit.

[0069] CCD stands for Charge-Coupled Device.

[0070] CIS stands for Contact Image Sensor.

[0071] CMOS stands for Complementary Metal Oxide Semiconductor.

[0072] CPU stands for Central Processing Unit.

[0073] HDD stands for Hard Disk Drive.

[0074] LAN stands for Local Area Network.

[0075] MFP stands for Multi-Function Peripheral.

[0076] RAM stands for Random-Access Memory.

[0077] ROM stands for Read Only Memory.

[0078] SSD stands for Solid State Drive. [Explanation of Symbols]

[0079] 100 MFP 140 Printers 400 Reader< / mfp>

Claims

1. An image forming system in which, in an image forming unit, the Nth sheet on which an image has been formed on the first surface is circulated and transported to the image forming unit as a sheet to be image formed after the N+i sheets that follow the first sheet, and an image is formed on the second surface of the Nth sheet, A reading means for reading the sheet after the image has been formed in the image forming unit, During a series of image formation processes in which images are formed on multiple sheets, an acquisition means acquires, based on the reading results of the multiple sheets by the reading means during the series of image formation processes, a second adjustment value updated from a first adjustment value for the first surface and a fourth adjustment value updated from a third adjustment value for the second surface as adjustment values ​​to be used for image formation. Control means for controlling the image forming unit to process such that, during a portion of the series of image forming processes, the updated second adjustment value for the first surface and the unupdated third adjustment value for the second surface are simultaneously stored in the storage unit, and without interrupting the series of image forming processes, an image is formed on the first surface of the N+i sheet using the updated second adjustment value for the first surface, and then an image is formed on the second surface of the N sheet using the unupdated third adjustment value for the second surface. An image forming system characterized by having the following features.

2. The image forming system according to claim 1, characterized in that the aforementioned partial period is the period from when the updated second adjustment value is obtained until all sheets on the first surface, which have been image-formed on them using the updated second adjustment value for the first surface, are circulated and transported to the image forming unit.

3. The image forming system according to claim 1, characterized in that the aforementioned partial period is the period from when an image is formed on the first surface using the second adjustment value before updating for all sheets on the first surface, until an image is formed on the second surface using the fourth adjustment value before updating for the second surface.

4. The image forming system according to claim 1, characterized in that when forming an image on the second surface of the Nth sheet, it is determined whether the first surface of the Nth sheet was formed with the first adjustment value before the update or with the second adjustment value after the update, and based on the result of the determination, it is determined whether to use the third adjustment value before the update or the fourth adjustment value after the update for forming the image on the second surface.

5. The image forming system according to claim 1, characterized in that, when forming an image on the second surface of the Nth sheet, it is determined whether the image forming on the first surface of the Nth sheet was performed before or after the timing of acquiring the updated second adjustment value, and based on the result of the determination, it is determined whether to use the first adjustment value before the update or the second adjustment value after the update for forming the image on the second surface.

6. The image forming system according to any one of claims 1 to 5, characterized in that the adjustment value is obtained based on the reading result of a sheet on which a predetermined mark has been image-formed during the series of image forming processes.

7. The image forming system according to claim 6, characterized in that the predetermined mark is formed on a sheet that is output separately from the output of the series of image forming processes.

8. The image forming system according to claim 6, characterized in that the predetermined marks are formed on the sheet edges of the output products of the series of image forming processes.

9. The image forming system according to any one of claims 1 to 8, characterized in that the adjustment value is a value for adjusting the position of the image formed on the sheet.

10. The image forming system according to any one of claims 1 to 8, characterized in that the control means controls the image forming unit to form an image in which the image position has been corrected based on the adjustment value.

11. The image forming system according to claim 1, characterized in that the control means controls the image forming unit to form an image in which the density has been corrected based on the adjustment value.

12. The image forming system according to any one of claims 1 to 11, characterized in that it can simultaneously store the first adjustment value and the second adjustment value for the first surface, and the third adjustment value and the fourth adjustment value for the second surface.

13. A control method for an image forming system, wherein the Nth sheet, on which an image has been formed on its first surface, is circulated and transported to the image forming unit as a sheet to be image formed after the N+i sheets that follow the first sheet, and an image is formed on the second surface of the Nth sheet, A reading step of reading the sheet after the image has been formed in the image forming unit, During a series of image formation processes in which images are formed on multiple sheets, an acquisition step is performed to acquire, based on the reading results of the multiple sheets in the reading step during the series of image formation processes, a second adjustment value updated from a first adjustment value for the first surface and a fourth adjustment value updated from a third adjustment value for the second surface as adjustment values ​​to be used for image formation. A control step to control the image forming unit so that, during a portion of the series of image forming processes, the updated second adjustment value for the first surface and the unupdated third adjustment value for the second surface are simultaneously stored in the storage unit, and without interrupting the series of image forming processes, an image is formed on the first surface of the N+i sheet using the updated second adjustment value for the first surface, and then an image is formed on the second surface of the N sheet using the unupdated third adjustment value for the second surface; A control method for an image forming system, characterized by having the following features.

14. A program for causing a computer to execute the control method for the image forming system described in claim 13.

Images