Image forming apparatus and control method thereof

Abstract

The present invention provides an image forming apparatus and a control method for an image forming apparatus. An image forming apparatus including a plurality of sheet feeding cassettes includes a control unit. The control unit performs control. When a predetermined condition is satisfied during a print job for printing image data, the control unit performs control to execute an interruption process of a correction job for a print correction block. The control unit performs control to determine, from the plurality of sheet feeding cassettes, a sheet feeding cassette to be used for the correction job based on information about the sheet feeding cassette used for the print job.

Description

Technical Field

[0001] The present invention relates to an image forming apparatus and a control method for the image forming apparatus. Background Art

[0002] There is known a printing system in which an inline sensor is disposed downstream of a printing apparatus that forms an image on a sheet, and the inline sensor reads the image on the sheet formed by the printing apparatus. Such a printing system adjusts image quality and the like in such a manner that, while processing a print job, in some cases, the printing apparatus prints a patch at a predetermined timing, and the inline sensor reads the patch. Japanese Patent Application Laid-Open No. 2010-122377 discusses a method in which settings of a sheet feeding cassette and a range of allowable density variations of an output product printed using a sheet from the sheet feeding cassette are received from a user, an interval at which a patch-printing sheet is inserted is determined based on the settings, and the density is controlled so as not to exceed the variation range.

[0003] However, in the method discussed in Japanese Patent Application Laid-Open No. 2010-122377, the settings are made without considering the print job. In a case where the sheet for the print job and the sheet for the patch are different from each other, it is necessary to change the sheet feeding cassette, printing conditions, and the like while processing the print job. Therefore, continuity of processing may be lost and productivity may be degraded. Further, in a case where image quality and the like are adjusted by using a sheet of a type different from the type of the sheet for the print job, the quality of the output product may be degraded. Summary of the Invention

[0004] The exemplary image forming apparatus disclosed herein is directed to a technique for ensuring the quality of an output product generated by an image forming apparatus while reducing degradation of productivity.

[0005] According to an aspect of the present disclosure, an image forming apparatus including a plurality of sheet feeding cassettes, the image forming apparatus includes: a control unit configured to perform control, wherein, when a predetermined condition is satisfied during execution of a print job for printing image data, the control unit performs control to execute an interruption process of a correction job for printing a correction patch, and wherein the control unit performs control to determine, from the plurality of sheet feeding cassettes, a sheet feeding cassette to be used for the correction job based on information about the sheet feeding cassette for the print job.

[0006] Additional features of the present disclosure will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. Brief Description of the Drawings

[0007] Figure 1 is a diagram showing a configuration example of a printing system.

[0008] Figure 2A It is a diagram showing an example of the hardware configuration of an image forming apparatus.

[0009] Figure 2B It is a diagram showing an example of the hardware configuration of an information processing apparatus.

[0010] Figure 3 It is a diagram showing an example of the functional configuration of an image forming apparatus.

[0011] Figure 4A and Figure 4B They are diagrams each showing an example of a setting screen.

[0012] Figure 5A It is a diagram showing the positional relationship between a gray block and a color measurement unit.

[0013] Figure 5B It is a diagram showing the positional relationship between a gray block and a color measurement unit.

[0014] Figure 5C It is a diagram showing examples of a reference value, a measured value, and a correction value.

[0015] Figure 5D It is a diagram showing an example of a reference value management table.

[0016] Figure 5E It is a diagram showing an example of a correction value management table.

[0017] Figure 6 It is a flowchart showing a sheet replacement process.

[0018] Figure 7A and Figure 7B They are diagrams each showing an example of a setting screen.

[0019] Figure 8 It is a flowchart showing details of a reference value / correction value deletion process.

[0020] Figure 9 It is a flowchart showing a print job execution process.

[0021] Figure 10 It is a flowchart showing a correction job execution process according to a first exemplary embodiment.

[0022] Figure 11 It is a flowchart showing details of a reference value / correction value registration process.

[0023] Figure 12 It is a diagram showing an example of a mode setting screen.

[0024] Figure 13 It is a diagram showing an example of a registration list.

[0025] Figure 14 is a flowchart showing the correction job execution process according to the second exemplary embodiment. Detailed implementation

[0026] Exemplary embodiments of the present disclosure will be described below with reference to the accompanying drawings.

[0027] Figure 1 is a diagram showing an example of the configuration of a printing system according to the first exemplary embodiment. As Figure 1 shown, the printing system includes a printing device 101 and an information processing device 102. Both the printing device 101 and the information processing device 102 have a communication function and are connected to a network 100 such as a wireless or wired local area network (LAN). Print data received from the information processing device 102 can be printed by the printing device 101. During the execution of a print job to print the print data, the printing device 101 performs an interruption process of the correction job to print a correction gray block, and performs a correction process using the result obtained by measuring the color of the printed gray block. In addition, the printing device 101 includes a plurality of sheet feeding cassettes in which sheets can be set.

[0028] In the first exemplary embodiment, a form is described in which the printing device 101 prints a gray block on a sheet fed from the sheet feeding cassette for the sheet immediately before the page being printed before the interruption process.

[0029] FIG. 2 is a diagram showing an example of the hardware configuration of the printing device 101 according to the present exemplary embodiment. The printing device 101 has a function of forming an image on a sheet. In the present exemplary embodiment, the printing device 101 is described as an example of an image forming device; however, the image forming device may be, for example, a multi-functional peripheral (MFP) that also has a scanner function and a facsimile (FAX) function. The printing device 101 includes a central processing unit (CPU) 201, a read-only memory (ROM), a random access memory (RAM), a storage 204, an operation unit interface (I / F) 205, an operation unit 206, an image processing unit 207, a communication unit I / F 208, a printing unit 209, and a color measurement unit 210. These units are interconnected via a bus 250.

[0030] The CPU 201 controls the entire printing apparatus 101. The CPU 201 loads programs stored in the ROM 202 or the memory 204 into the RAM 203 and executes these programs. As a result, various functions and processes shown in the flowcharts described below are implemented. In addition to the control program and various programs that can be executed by the CPU 201, the ROM 202 also stores a reference value management table, a correction value management table, etc., which are described below. The RAM 203 is the main memory of the CPU 201. The RAM 203 temporarily stores various data such as reference values and correction values, which are described below, and is used as a work area or a temporary storage area for loading programs. The memory 204 stores a control program, various programs, setting information, print data, data on gray blocks, etc. In the present exemplary embodiment, an auxiliary storage device such as a hard disk drive (HDD) is used as the memory 204; however, a non-volatile memory such as a solid state drive (SSD) can be used as the memory 204.

[0031] In the printing apparatus 101 according to the present exemplary embodiment, one CPU 201 performs the processes shown in the flowcharts described below by using one memory (RAM 203); however, other forms can also be adopted. For example, the printing apparatus 101 can cause a plurality of CPUs, RAMs, ROMs, and memories (storages) to cooperate with each other to perform the processes shown in the flowcharts described below. In addition, the printing apparatus 101 can perform part of the processes by using hardware circuits such as application specific integrated circuits (ASICs) and field programmable gate arrays (FPGAs).

[0032] The operation unit I / F 205 is an interface that connects the operation unit 206 and the CPU 201. The operation unit 206 includes a touch panel and various hardware keys, and has a display function for displaying information and an input function for receiving input from the user.

[0033] The image processing unit 207 has a raster image processor (RIP) function to convert the print data received through the communication unit I / F 208 into printable image data. In addition, the image processing unit 207 can perform resolution conversion and correction processing on the image data under the control of the CPU 201. In the present exemplary embodiment, it is assumed that the image processing unit 207 is implemented by a hardware circuit (such as an ASIC and an FPGA); however, the image processing unit 207 is not limited thereto, and other configurations can be adopted. For example, the printing apparatus 101 may include a processor for image processing as the image processing unit 207, and the processor may execute an image processing program to perform the above-described image processing. In this case, the processor and the CPU 201 cooperate with each other to perform the processing shown in the flowchart described below. In addition, the CPU 201 may serve as the image processing unit 207 and perform the above-described image processing. Alternatively, any of these configurations may be combined to perform the above-described image processing.

[0034] The printing unit (printer engine) 209 prints an image on a sheet fed from the sheet feeding cassette based on the image data generated by the image processing unit 207 under the control of the CPU 201. In the present exemplary embodiment, the printing method of the printing unit 209 is the electrophotographic method; however, the printing method is not limited thereto, and other methods such as the inkjet method and the thermal transfer method may be used.

[0035] The color measurement unit 210 is a device that measures the color of an image printed on a sheet, and is provided downstream of the printing unit 209 in the transport direction. The color measurement unit 210 is a device that reads an image formed by the printing unit 209 on a recording medium, and is, for example, an in-line sensor. As the color measurement unit 210, a contact image sensor (CIS) may be used; however, the color measurement unit 210 is not limited thereto, as long as the color measurement unit 210 can measure the color of the image on the sheet. In the present exemplary embodiment, an in-line sensor is used as the color measurement unit 210. The in-line sensor measures the density of a gray scale block printed on the sheet under the control of the CPU 201, and provides the measurement result to the CPU 201 as color measurement data.

[0036] The CPU 201 is connected to the network 100 through the communication unit I / F 208. The CPU 201 receives a print request (print data) from the information processing apparatus 102 on the network 100 through the communication unit I / F 208.

[0037] FIG. 2 is a diagram showing an example of the hardware configuration of the information processing apparatus 102 according to the present exemplary embodiment. For example, the information processing apparatus 102 is a personal computer. The information processing apparatus 102 includes a CPU 211, a memory 212, a storage device 213, a display device 214, an input device 215, and a communication unit I / F 216. These units are interconnected via a bus 260.

[0038] The CPU 211 executes programs stored in the storage device 213 to perform various functions described below. The memory 212 temporarily stores programs and data read out by the CPU 211 from the storage device 213. The storage device 213 stores programs, data, etc., such as an operating system (OS) and a printer driver. The display device 214 displays setting contents required for printing, etc. The input device 215 includes a keyboard and a mouse, and receives inputs from the user. The CPU 211 is connected to the network 100 via the communication unit I / F 216. The CPU 211 sends a print request (print data) to the printing apparatus 101 on the network 100 via the communication unit I / F 216.

[0039] Figure 3 is a diagram showing an example of the functional configuration of the printing apparatus 101 according to the present exemplary embodiment. When the CPU 201 reads and executes a program stored in the ROM 202 or the memory 204, the printing apparatus 101 functions as Figure 3 the functional units shown in

[0040] When the data reception control unit 302 receives page description language (PDL) data (print data), the print job generation unit 301 generates a print job. The job control unit 303 registers the generated print job and controls the registered print jobs to proceed in sequence. The job control unit 303 instructs the page control unit 304 to start print processing for all the pages included in the registered print job starting from the first page. In response to the instruction to start print processing from the job control unit 303, the page control unit 304 performs print processing on the pages in sequence. After the print processing for all the pages included in the print job is completed, the job control unit 303 notifies the print job generation unit 301 that the job is completed.

[0041] The data reception control unit 302 receives PDL data (print data) transmitted from the information processing apparatus 102 via the communication unit I / F 208. The PDL analysis unit 305 analyzes the received PDL data and converts the received PDL data into intermediate data. The RIP control unit 306 controls the image processing unit 207 to perform rasterization processing on the converted intermediate data to generate image data in bitmap format. The image generation unit 307 performs correction processing on the generated image data in bitmap format. More specifically, the image generation unit 307 generates a corrected print image by reflecting the correction values stored in the correction information storage unit 310 in the image data. Thereafter, in order to print gray blocks on the margin of the sheet, the image generation unit 307 supplies the corrected print image to the block combination unit 309 of the engine control unit 308.

[0042] The engine control unit 308 includes a block combination unit 309, a correction information storage unit 310, a reference information storage unit 311, a color measurement sensor control unit 312, a sheet feed cassette management unit 313, a sheet feed control unit 314, and a print control unit 315. The block combination unit 309 combines the gray blocks with the corrected print image received from the image generation unit 307. Thereafter, the block combination unit 309 instructs the print control unit 315 to print the combined image. The sheet feed control unit 314 controls the sheet feed cassette corresponding to the instruction of the print job to convey and feed the sheet set in the sheet feed cassette. The print control unit 315 prints the combined image on the sheet fed from the sheet feed cassette and discharges the sheet.

[0043] The color measurement sensor control unit 312 controls the color measurement unit 210. More specifically, the color measurement sensor control unit 312 controls the color measurement unit 210 to measure the color of the gray blocks printed on the sheet and acquire color measurement data. The reference information storage unit 311 stores reference values generated based on the color measurement data acquired by the color measurement sensor control unit 312 for each sheet type. The correction information storage unit 310 stores correction values for each sheet type, and the correction values are determined by comparing the reference values stored in the reference information storage unit 311 with the measurement values generated based on the color measurement data acquired by the color measurement sensor control unit 312.

[0044] The sheet feeding cassette management unit 313 manages the types of sheets set in each sheet feeding cassette. More specifically, in response to a sheet registration request from the user interface (UI) control unit 316, the sheet feeding cassette management unit 313 deletes the reference value of the sheet type to be removed for replacement among the reference values stored in the reference information storage unit 311. When a correction value of the sheet type to be removed for replacement is stored in the correction information storage unit 310, the sheet feeding cassette management unit 313 also deletes the correction value. When a sheet replacement instruction to replace the sheet in the sheet feeding cassette is received from the operation unit 206, the UI control unit 316 issues a sheet registration request to the sheet feeding cassette management unit 313.

[0045] Refer to Figure 4A and Figure 4B A setting screen for image adjustment is described. In the present exemplary embodiment, the CPU 201 of the printing apparatus 101 performs interruption processing of a correction job during the execution of a printing job to print a gray block, and reflects the correction value obtained by using the color measurement data of the gray block in real time on the printing process of subsequent pages. This function is called a real-time multi-gray correction function. The real-time multi-gray correction function reduces gray variations in a printing job. The real-time multi-gray correction function has two types: one is a margin utilization type in which a gray block is printed on the sheet margin of each page for correction processing; the other is a chart insertion type in which sheets (hereinafter referred to as charts) on which only gray blocks are printed are inserted at predetermined intervals for correction processing. The chart insertion type is effective for cases where the sheet margin cannot be used. Based on the setting content set for the printing apparatus 101 by the information processing apparatus 102, it is determined which of the margin utilization type and the chart insertion type is to be used. In the present exemplary embodiment, since the correction job is a job of only printing gray blocks, the control content of the chart insertion type is described, and the description of the control content of the margin utilization type is omitted.

[0046] Figure 4A FIG. is an example of a setting screen displayed on the display device 214 of the information processing apparatus 102. The CPU 211 of the information processing apparatus 102 executes a program stored in the storage device 213 to display the setting screen 400 on the display device 214. The CPU 211 of the information processing apparatus 102 receives an input of the setting content for the printing apparatus 101 via the setting screen 400. The setting screen 400 includes labels 401 to 406 corresponding to the setting content, and displays the labels selected by the user.

[0047] The adjustment label 404 is displayed on Figure 4A the setting screen 400 in. The adjustment label 404 includes an adjustment item setting field 407 and an adjustment method setting field 408.

[0048] The adjustment item setting field 407 is a display field for setting adjustment items to be adjusted by the printing apparatus 101 using the color measurement unit 210. Here, an example is given where, as the adjustment item setting field 407, check boxes for "front / rear image position" and "gray scale" are displayed as selectable options, and both "front / rear image position" and "gray scale" are selected by the user. The adjustment items selected in the adjustment item setting field 407 are set as adjustment items of the printing apparatus 101, and adjustments are made based on these adjustment items. The item "gray scale" indicates the above-described real-time multi-gray-scale correction function. The item "front / rear image position" indicates the front / rear registration adjustment function for adjusting the positions of images printed on the front and rear surfaces of the sheet. A detailed description of "front / rear image position" is omitted.

[0049] The adjustment method setting field 408 is a display field for setting adjustment methods for the adjustment items selected in the adjustment item setting field 407. Here, an example is given where radio buttons for "margin utilization type" and "chart insertion type" are displayed as selectable options in the adjustment method setting field 408, and "chart insertion type" is selected by the user.

[0050] In Figure 4A In addition to the above-described adjustment label 404 shown in the example, other labels are the basic setting label 401, the page setting label 402, the collation label 403, the sheet feed label 405, and the print quality label 406. The basic setting label 401 is used to make basic settings such as the number of copies, print orientation, magnification, and output method. The page setting label 402 is used to make settings such as the page layout and magnification of the image. The collation label 403 is used to make settings for single-sided / double-sided printing, binding orientation, and discharge method. The sheet feed label 405 is used to make settings for the sheet feed cassette for feeding sheets. The print quality label 406 is used to make settings related to image quality such as color mode (color / monochrome) and resolution. When the OK (OK) button 409 provided in the setting screen 400 is pressed, the CPU 211 of the information processing apparatus 102 sends the setting contents input in the labels 401 to 406 and the print request to the printing apparatus 101 via the communication unit I / F 216.

[0051] Figure 4B is a diagram showing an example of a setting screen displayed on the operation unit 206 of the printing apparatus 101. In Figure 4A When "gray scale" and "chart insertion type" are respectively selected in the adjustment item setting field 407 and the adjustment method setting field 408 in Figure 4BThe setting screen 420 shown in the figure. The setting screen 420 is used to set the chart insertion interval in the case of the chart insertion type for the real-time multi-gray correction function. The user operates the icon 422 or the numeric keypad (not shown) to set the discharge page number 421. When the OK button 423 is pressed, the CPU 201 of the printing apparatus 101 stores the set page number 421 as the chart insertion interval in the memory 204. As a result, every time the number of discharged pages reaches the chart insertion interval, the printing apparatus 101 performs an interruption process of the correction operation.

[0052] Next, refer to Figure 5A and Figure 5B to describe the positional relationship between the printing positions of the gray blocks and the color measurement unit 210. As Figure 5A shown, the in-line sensors 551 and 552 as the color measurement unit 210 are respectively provided at the left end and the right end in the conveyance direction. The gray blocks 510, 520, 530, and 540 are printed at positions corresponding to the reading positions of the in-line sensors 551 and 552 on the sheet 500. More specifically, the gray blocks 510 to 540 of the colors CMYK corresponding to the developers 561 to 564 of the colors CMYK ( Figure 5B ) are printed in the margin area outside the print guarantee area 501 provided on the sheet 500. Each of the gray blocks 510 to 540 includes ten blocks, and the toner concentration of the corresponding color in the colors CMYK is from 10% to 100% at intervals of 10%. The gray blocks 510 to 540 are all examples of correction blocks. In the case of selecting the "chart insertion type", the gray blocks can be printed in the print guarantee area 501. When the gray blocks are printed in the margin area, the "margin utilization type" and the "chart insertion type" can be switched as needed, while the reading positions of the in-line sensors 551 and 552 are fixed.

[0053] Figure 5B is a cross-sectional view showing the conveyance direction in the printing apparatus 101 when viewed from the side. The printing apparatus 101 prints the gray blocks 510 to 540 on the sheet 500 by transferring the toner to the sheet 500 with the developers 561 to 564 of the corresponding colors CMYK and causing the fixing device 565 to perform a fixing process to fix the toner to the sheet 500. Thereafter, the printing apparatus 101 controls the in-line sensors 551 and 552 to obtain information on the concentration of the colors CMYK from the gray blocks 510 to 540 as color measurement data. The printing apparatus 101 performs a correction process based on the color measurement data.

[0054] Next, refer to Figure 5C , Figure 5D and Figure 5E to describe the data for the correction process performed by the printing apparatus 101. Figure 5CIt is a diagram showing an example of a reference value, a measured value, and a correction value generated based on color measurement data regarding gray blocks. The printing apparatus 101 generates a reference value, a measured value, and a correction value based on color measurement data regarding gray blocks 510 to 540 acquired by the in-line sensors 551 and 552. As Figure 5C shown, each value among the reference value 571, the measured value 572, and the correction value 573 includes concentration information regarding each color of CMYK for ten blocks (i.e., a total of forty blocks). The concentration information is converted into a numerical value on a 1024-level scale.

[0055] First, the printing apparatus 101 stores the acquired color measurement data as the reference value 571, and registers the reference value 571 in association with the sheet type in the reference value management table ( Figure 5D ). Next, when the printing apparatus 101 acquires color measurement data regarding a sheet type for which the reference value has not been registered yet, the printing apparatus 101 stores the color measurement data as a new reference value 571 and registers the reference value 571 in the reference value management table. In contrast, when the printing apparatus 101 acquires color measurement data regarding a sheet type for which the reference value has already been registered, the printing apparatus 101 processes the color measurement data as the measured value 572, and calculates the correction value 573 by using the difference between the reference value 571 corresponding to the sheet type and the measured value 572. In addition, the printing apparatus 101 stores the calculated correction value 573, and registers the correction value 573 in association with the sheet type in the correction value management table ( Figure 5E ). In the present exemplary embodiment, the printing apparatus 101 stores the correction value 573; however, the printing apparatus 101 may store the measured value 572 instead of the correction value 573, and may calculate the correction value 573 based on the difference between the reference value 571 and the measured value 572 when performing the correction process.

[0056] Figure 5DThis is a diagram showing an example of a reference value management table. The records registered in the reference value management table include sheet type 581, target sheet feed cassette 582, reference value (1 / 2 speed) 583, reference value (1 / 1 speed) 584, generated page identifier (ID) 585, and timestamp 586. The sheet type 581 is information about the sheet type used when obtaining the reference value. The target sheet feed cassette 582 is information about the sheet feed cassette used when obtaining the reference value. The reference value (1 / 2 speed) 583 and the reference value (1 / 1 speed) 584 are information indicating the presence or absence of a reference value and the reference destination of the reference value. Both 1 / 1 speed and 1 / 2 speed indicate the image forming speed. In other words, the printing apparatus 101 can perform different correction processes for each image forming speed. The generated page ID 585 is information for identifying the chart used when obtaining the reference value. In this example, the cumulative value indicating the number of pages discharged after the printing apparatus 101 is turned on until the chart is inserted is used as the generated page ID 585. The timestamp 586 is information about the date and time when the printing apparatus 101 is turned on.

[0057] Figure 5D An example in which a reference value (TBL 571) has been registered is shown. The reference value (TBL 571) was obtained by feeding "plain paper 3" at "1 / 1 speed" from "sheet feed cassette 1 (CSTl)" during the printing process on page "60014" after the printing apparatus 101 was turned on at "2019 / 07 / 18 10:04:06". When "plain paper 3" is removed from "sheet feed cassette 1 (CSTl)", the printing apparatus 101 deletes the record including "plain paper 3" from the reference value management table. The printing apparatus 101 also deletes the reference value in the reference destination specified by this record.

[0058] Figure 5E This is a diagram showing an example of a correction value management table. The records registered in the correction value management table include sheet type 591, target sheet feed cassette 592, correction value (1 / 2 speed) 593, correction value (1 / 1 speed) 594, generated page ID 595, and timestamp 596. This correction value management table is similar to the reference value management table in Figure 5D except that the correction value (1 / 2 speed) 593 and the correction value (1 / 1 speed) 594 replace the reference value (1 / 2 speed) 583 and the reference value (1 / 1 speed) 584, respectively. Therefore, repeated descriptions are omitted.

[0059] Figure 5EAn example in which a correction value (TBL 573) has been registered is shown. The correction value (TBL 573) was obtained by feeding "plain paper 3" from "sheet feed cassette 1 (CST1)" at a "1 / 1 speed" in the printing process on page "640015" after the printing device 101 was turned on at "2019 / 07 / 18 18:34:21".

[0060] Next, refer to Figures 6 to 8 Describe the sheet replacement process for replacing the sheet set in the sheet feed cassette. Figure 6 is a flowchart showing the sheet replacement process. When the CPU 201 of the printing device 101 reads the program stored in the ROM 202 into the RAM 203 and executes the program, the processing in the Figure 6 flowchart is implemented.

[0061] First, in step S601, the CPU 201 receives a request to display a setting screen for setting the sheet set in the sheet feed cassette by user operation. Figure 7A is a diagram showing an example of the setting screen.

[0062] Next, in step S602, the CPU 201 reads and obtains the setting information on the sheet size and sheet type of the sheet set in the sheet feed cassette of the printing device 101 from the memory 204.

[0063] Next, in step S603, the CPU 201 displays on the operation unit 206 a setting screen reflecting the information obtained in step S602. In the Figure 7A setting screen 700, the sheet size is displayed in the selection buttons 701 to 704 assigned to the corresponding sheet feed cassettes. In the Figure 7A example, sheet feed cassette 1 is selected, and the sheet type set in sheet feed cassette 1 is displayed.

[0064] Next, in step S604, select the selection button for the sheet feed cassette whose sheet is to be changed, press the setting button 705, and then press the OK button 706. In step S605, the CPU 201 displays a sheet type setting screen on the operation unit 206. Figure 7B is a diagram showing an example of the sheet type setting screen. In the Figure 7B setting screen 710, a list of sheet types that can be set is displayed. After selecting the sheet type (plain paper 3 in this example) to be set in the sheet feed cassette selected in step S604 and pressing the OK button 708, then in step S606, the CPU 201 performs processing to delete the reference value and correction value of the sheet type to be removed for sheet replacement.

[0065] Next, the details of the processing in step S606 will be described with reference to Figure 8 the flowchart in

[0066] Figure 8 FIG.

[0067] First, in step S801, the CPU 201 determines whether the sheet type in the record of the selected sheet feeding cassette has changed by referring to the records registered in the reference value management table and the correction value management table.

[0068] If the CPU 201 determines that the sheet type has not changed (i.e., the same sheet type is set again) (No in step S801), the process returns to Figure 6 the flowchart in

[0069] Conversely, if the CPU 201 determines that the sheet type has changed (Yes in step S801), the process proceeds to step S802.

[0070] In step S802, the CPU 201 determines whether the same sheet type as the sheet type before the change has been registered in any other sheet feeding cassette. If the CPU 201 determines that the same sheet type as the sheet type before the change has not been registered in any other sheet feeding cassette (No in step S802), the process proceeds to step S803.

[0071] In step S803, the CPU 201 deletes the reference value and the correction value of the sheet type before the change from the reference information storage unit 311 and the correction information storage unit 310. Then, the process proceeds to step S804. Conversely, if the CPU 201 determines in step S802 that the same sheet type as the sheet type before the change has been registered in any other sheet feeding cassette (Yes in step S802), the process proceeds to step S804 without deleting the reference value and the correction value of this sheet type.

[0071] In step S804, the CPU 201 deletes the record of the selected sheet feeding cassette from each of the reference value management table and the correction value management table. Thereafter, the process proceeds to Figure 6 step S607 in

[0072] In step S607, the CPU 201 displays a setting screen on the operation unit 206 that reflects the sheet type after the change. The series of processes in the flowchart ends.

[0073] According to the processing in the flowchart described above, the correspondence between the sheet feeding cassette and the sheet type, as well as the reference value and the correction value of each sheet type, can be appropriately managed.

[0074] Subsequently, with reference toFigures 9 to 11 Describe the processing performed during the execution of a printing job. Figure 9 It is a flowchart showing the processing of printing job execution. When the CPU 201 of the printing apparatus 101 reads the program stored in the ROM 202 into the RAM 203 and executes the program, the processing in the Figure 9 flowchart is realized. When the printing apparatus 101 receives a print request (print data) from the information processing apparatus 102, the processing in the Figure 9 flowchart starts.

[0075] First, in step S901, the CPU 201 generates and registers a printing job to print the received print data.

[0076] Next, in step S902, when the CPU 201 starts to execute the printing job registered in step S901, the CPU 201 sets the value N of the number of pages of the printing job to 1.

[0077] Next, in step S903, the CPU 201 instructs each unit to start the printing process on the Nth page.

[0078] Next, in step S904, the CPU 201 determines the sheet feed cassette from which to feed the sheet based on the sheet size and sheet type (hereinafter referred to as sheet information) specified for the Nth page of the printing job.

[0079] Next, in step S905, the CPU 201 feeds the sheet from the sheet feed cassette determined in step S904, and stores the sheet information and the information about the sheet feed cassette used for feeding the sheet in the RAM 203. In other words, the CPU 201 serves as a storage unit that stores the information about the sheet feed cassette for the page in the printing process. Each time the page printing process is performed, the sheet information and the information about the sheet feed cassette stored in the RAM 203 are updated.

[0080] Next, in step S906, the CPU 201 determines whether a record of the sheet feed cassette used for sheet feeding has been registered by referring to the target sheet feed cassette 592 in the correction value management table. When the CPU 201 determines that the record has been registered (Yes in step S906), the processing proceeds to step S907.

[0081] In step S907, the CPU 201 reads out the correction value from the correction information storage unit 310 by using the registered record. When two or more records have been registered, the CPU 201 reads out the correction value of the latest record by referring to the generation page ID 585 in the correction value management table. The CPU 201 generates a print image in which the read correction value is reflected on the image data of the Nth page. Then, the process proceeds to step S909.

[0082] On the contrary, when the CPU 201 determines in step S906 that the record has not been registered ( "No" in step S906), the process proceeds to step S908. In step S908, the CPU 201 generates an uncorrected print image. Then, the process proceeds to step S909.

[0083] In step S909, the CPU 201 prints the print image generated in step S908 on the sheet fed in step S905. Since the "chart insertion type" is selected in this exemplary embodiment, the gray blocks are not combined with the print image.

[0084] Next, in step S910, the CPU 201 increments the discharge sheet number counter that stores the cumulative value indicating the number of discharged pages, and stores the value of the counter in the RAM 203. Then, the print processing of the Nth page ends.

[0085] Next, in step S911, the CPU 201 determines whether the Nth page is the last page of the print job. When the CPU 201 determines that the Nth page is not the last page ( "No" in step S911), the process proceeds to step S912. In step S912, the value of N is incremented and stored in the RAM 203, and the process returns to step S903. On the contrary, when the CPU 201 determines in step S911 that the Nth page is the last page ( "Yes" in step S911), the process proceeds to step S913. In step S913, the print job ends. Then, the series of processes in the flowchart ends.

[0086] During the execution of the above print job, the interruption process of the correction job described below is performed at a predetermined interval. As a result, the correction value generated in the correction job is reflected on the image generated in the print job after the interruption process, and the correction result can be continuously fed back to the subsequent pages. In other words, the gray scale change in the print job is reduced.

[0087] Figure 10 is a flowchart showing the execution process of the correction job. When the CPU 201 of the printing device 101 reads the program stored in the ROM 202 into the RAM 203 and executes the program, Figure 10Processing in the flowchart. When a print job is registered, it starts Figure 10 Processing in the flowchart.

[0088] First, in step S1001, each time the page printing process is completed, the CPU 201 determines whether the value of the discharged sheet counter has reached a preset chart insertion interval (shown in Figure 4B ). The process waits until the CPU 201 determines that the value of the discharged sheet quantity counter has reached the preset chart insertion interval ("No" in step S1001). When the CPU 201 determines that the value of the discharged sheet quantity counter has reached the preset chart insertion interval ("Yes" in step S1001), the process proceeds to step S1002.

[0089] In this exemplary embodiment, when the number of discharged pages has reached the set value as a trigger, interrupt processing is performed; however, the conditions for performing the interrupt processing are not limited to this, and other conditions, such as a predetermined time elapsed since the start of printing, can also be used as a trigger.

[0090] In step S1002, the CPU 201 performs a process (interrupt processing) to interrupt the currently executing print job and generate and register a correction job to print a gray block. The CPU 201 serves as a control unit that controls the execution of the interrupt processing for the correction job.

[0091] Next, in step S1003, the CPU 201 reads information about the current sheet feeding cassette from the RAM 203. The CPU201 determines the sheet feeding cassette from which to feed the sheet based on the read information about the sheet feeding cassette, and feeds the sheet from the determined sheet feeding cassette. More specifically, the sheet is fed from the sheet feeding cassette specified by the read information about the sheet feeding cassette. In other words, the CPU 201 feeds the sheet from the same sheet feeding cassette as the one used for the page printing process immediately before the interrupt processing.

[0092] Next, in step S1004, the CPU 201 reads the current sheet information from the RAM 203 and generates a gray block print image based on the read sheet information.

[0093] Next, in step S1005, the CPU 201 prints the print image generated in step S1004 on the sheet fed in step S1003.

[0094] After the printing is completed, then in step S1006, the CPU 201 causes the color measurement unit 210 to measure the color of the gray block on the sheet and obtains color measurement data from the color measurement unit 210.

[0095] Next, in step S1007, the CPU 201 performs processing to register the reference value and correction value generated using the color measurement data. The details of the processing in step S1007 will be described below with reference to Figure 11 the details of the processing in step S1007 are described.

[0096] Next, in step S1008, the CPU 201 ends the correction job. After that, the CPU 201 resumes the execution of the print job.

[0097] According to the processing in the flowchart as described above Figure 10 of the flowchart, the printing apparatus 101 feeds the sheet to be used for the correction job from the sheet feed cassette used in the printing process of the page immediately before the interruption process. This makes it possible to print the gray scale blocks without changing the sheet feed cassette, the printing conditions, etc., and does not hinder the continuity of the processing. The sheet feed cassette that feeds the sheet used for the correction job does not necessarily have to be the sheet feed cassette used for printing the page immediately before the interruption process, and can be the sheet feed cassette used for printing other pages, as long as the sheet feed cassette is used for printing the pages included in the print job. For example, the sheet feed cassette used for printing the page immediately after the interruption process can be used. In this case, the printing apparatus 101 analyzes the print job and acquires information about the sheet feed cassette.

[0098] Subsequently, the details of the processing in step S1007 will be described with reference to Figure 11 the flowchart.

[0099] Figure 11 is a flowchart showing the details of the processing for registering the reference value and the correction value.

[0100] First, in step S1101, the CPU 201 determines whether a record of the sheet feed cassette used in step S1003 has been registered by referring to the target sheet feed cassette 582 in the reference value management table. When the CPU 201 determines that the record has been registered (Yes in step S1101), the CPU 201 reads out the reference value from the reference information storage unit 311 using the record. Then, the processing proceeds to step S1106. On the contrary, when the CPU 201 determines in step S1101 that the record has not been registered (No in step S1101), the processing proceeds to step S1102.

[0101] In step S1102, the CPU 201 determines whether a record of the sheet type used in step S1004 has been registered by referring to the sheet type 581 in the reference value management table. When the CPU 201 determines that the record has not been registered (No in step S1102), the processing proceeds to step S1103.

[0102] In step S1103, the CPU 201 stores the color measurement data obtained in step S1006 as a reference value in the reference information storage unit 311. Next, in step S1104, the CPU 201 performs a linking process to add this record to the reference value management table and refer to the reference value stored in step S1103. As a result, the new reference value is stored in association with the sheet type. Then, the process returns to Figure 10 the flowchart of

[0103] Conversely, when the CPU 201 determines in step S1102 that the record has already been registered (Yes in step S1102), the process advances to step S1105. In step S1105, the CPU 201 copies the registered record, adds this record to the reference value management table, and rewrites the information in the target sheet feeding cassette 582 using the information about the sheet feeding cassette used in step S1003. As a result, the reference value of the sheet type used in step S1004 is associated with the sheet feeding cassette used in step S1003. In addition, the CPU 201 reads out the reference value from the reference information storage unit 311 using this added record.

[0104] In step S1106, the CPU 201 calculates a correction value based on the difference between the color measurement data obtained in step S1006 as a measurement value and the read reference value.

[0105] Next, in step S1107, the CPU 201 stores the calculated correction value in the correction information storage unit 310. The CPU 201 further performs a linking process to add this record to the correction value management table and refer to the stored correction value. As a result, the correction value is stored in association with the sheet type. Then, the process returns to Figure 10 the flowchart of

[0106] According to the processing in the flowchart of Figure 11 as described above, the reference value to be referred to can be quickly specified by using the correspondence between the sheet feeding cassette and the sheet type. In addition, even when the sheet type and the sheet feeding cassette are not associated, if the same sheet type as the sheet type used for the correction operation is registered in other sheet feeding cassettes, the reference value to be referred to can also be specified.

[0107] In the printing apparatus 101 according to the first exemplary embodiment as described above, a correction operation is performed at a predetermined interval during the execution of a print job, and the density can be adjusted. This reduces the gradation variation in the print job. Further, since the sheet used for the correction operation is fed from the sheet feed cassette that was used for the print page immediately before the correction operation, the continuity of the processing is not hindered. Further, since the correction processing corresponding to the type of sheet used for the print job is performed, the quality of the output product is ensured.

[0108] In the first exemplary embodiment described above, the following form has been described: the printing apparatus 101 prints a gradation block on a sheet fed from the sheet feed cassette that was used for the print page immediately before the interruption processing. In this form, in the case where the print job includes pages of different sheet types, it may not be possible to print a gradation block on some types of sheets. Therefore, in the second exemplary embodiment, the following form is described: in the case where the print job includes pages of different sheet types, a gradation block is printed on a plurality of types of sheets. In the following description, functional configurations similar to those of the first exemplary embodiment are denoted by the same reference numerals, and the repeated description of these functional configurations is omitted. The differences from the first exemplary embodiment are mainly described.

[0109] Figure 12 is a diagram showing an example of a mode setting screen. In response to a request to display a setting screen for setting a mode by user operation, the CPU 201 of the printing apparatus 101 displays Figure 12 the mode setting screen 1200 shown in. In the mode setting screen 1200, a selection button 1201 for the speed priority mode and a selection button 1202 for the image quality priority mode are displayed. As described in the flowchart with reference to Figure 10 , the speed priority mode is a mode (first mode) in which the correction operation is performed by using the sheet fed from the sheet feed cassette that was used for the print page immediately before the interruption processing. The image quality priority mode is a mode (second mode) in which the correction operation is performed by using all types of sheets used in the print processing performed between the chart insertion intervals. When any one of the selection buttons 1201 and 1202 is selected and the OK button 1203 on the mode setting screen 1200 is pressed, the printing apparatus 101 sets the selected mode. In other words, the CPU 201 of the printing apparatus 101 serves as a setting unit for setting either the speed priority mode or the image quality priority mode. When starting to execute a print job, the printing apparatus 101 performs Figure 10 the processing in the flowchart of and the processing in the flowchart described below Figure 14 any one of.

[0110] Figure 13 is a diagram showing an example of a registration list used in the image quality priority mode. As Figure 13 shown, the combination of information about the sheet feeding cassette and sheet information is recorded in the registration list. In the Figure 13 example, the combination of "sheet feeding cassette 1 (CST1)" and "plain sheet 3" and the combination of "sheet feeding cassette 4 (CST4)" and "coated sheet 1" are recorded. The printing apparatus 101 stores the registration list in the RAM 203 or the like, and initializes the registration list when starting to execute a print job or performing interrupt processing. When starting or resuming the execution of a print job, each time the printing apparatus 101 performs page printing processing, the printing apparatus 101 records the combination of information about the sheet feeding cassette and sheet information in the registration list. In this case, when the same combination of information about the sheet feeding cassette and sheet information has already been recorded, the printing apparatus 101 does not record the combination. As a result, all the information about the sheet feeding cassette and sheet information used in the printing process during the chart insertion interval (after starting to execute a print job or the time after the execution of the previous interrupt processing until the execution time of the current interrupt processing) is recorded in the registration list.

[0111] Figure 14 is a flowchart showing the correction job execution process. When the CPU 201 of the printing apparatus 101 reads the program stored in the ROM 202 into the RAM 203 and executes the program, the processing in the Figure 14 flowchart is realized. Figure 14 The flowchart of Figure 10 differs from the flowchart of

[0112] in that the processing in steps S1403 to S1405 is executed instead of the processing in step S1003, and the processing in steps S1410 and S1411 is performed between the processing in steps S1007 and S1008. The differences will be mainly described below, and the description of similar processing will be omitted.

[0113]

[0114] In step S1403, the CPU 201 refers to the registration list and acquires the combination of information about the sheet feeding cassette and sheet information recorded at the beginning of the registration list.

[0115] Next, in step S1404, the CPU 201 determines the sheet feeding cassette from which to feed the sheet based on the acquired information about the sheet feeding cassette in a manner similar to step S1003. Next, in step S1405, the CPU 201 feeds the sheet from the determined sheet feeding cassette.

[0116] Next, in step S1406, the CPU 201 generates a grayscale block print image based on the sheet information obtained in step S1403 in a manner similar to step S1004.

[0117] The processes in steps S1407 to S1409 are similar to the processes in steps S1005 to S1007.

[0118] In step S1410, the CPU 201 determines whether all combinations of the information on the sheet feeding cassette recorded in the registration list and the sheet information have been obtained. When the CPU 201 determines that all combinations have been obtained (Yes in step S1410), the process proceeds to step S1411. On the contrary, when the CPU 201 determines that there are combinations that have not been obtained (No in step S1410), the process returns to step S1403. The CPU 201 repeats the processes in steps S1403 to S1409 until all combinations of the information on the sheet feeding cassette and the sheet information are obtained. As a result, correction values for all sheet types used in the printing process performed between the chart insertion intervals can be generated.

[0119] In step S1411, the CPU 201 initializes the registration list. As a result, the information registered in the registration list before the execution of the current interrupt process is cleared, and the preparation for registering the information used in the printing process performed until the execution of the next interrupt process is completed.

[0120] Next, in step S1412, the CPU 201 ends the correction job. Then, the CPU 201 resumes the execution of the printing job.

[0121] In the printing apparatus 101 according to the second exemplary embodiment as described above, when the printing job includes pages of different sheet types, density adjustment can be performed on multiple types of sheets used in the printing process performed at predetermined intervals. This reduces the gray-scale variation in the printing job. In addition, since the gray-scale blocks are printed only on the sheet types used in the printing performed at predetermined intervals, performance degradation can be reduced as much as possible. Moreover, since the correction process corresponding to the sheet type is performed without omission, a high-quality output product can be provided to the user.

[0122] According to the exemplary embodiments of the present disclosure, while reducing the degradation of productivity, the quality of the output product of the image forming apparatus can be ensured.

[0123] Other embodiments

[0124] Embodiments of the present disclosure can also be implemented by a computer of a system or apparatus that reads and executes computer-executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be more fully referred to as a "non-transitory computer-readable storage medium") to perform one or more functions in the above embodiments and / or includes one or more circuits (e.g., an application specific integrated circuit (ASIC)) for performing one or more functions in the above embodiments. Moreover, embodiments of the present disclosure can be implemented by a method of, for example, the computer of the system or apparatus reading and executing the computer-executable instructions from the storage medium to perform one or more functions in the above embodiments and / or controlling the one or more circuits to perform one or more functions in the above embodiments. The computer may include one or more processors (e.g., a central processing unit (CPU), a microprocessing unit (MPU)), and may include a network of standalone computers or standalone processors to read and execute the computer-executable instructions. The computer-executable instructions may be provided to the computer, for example, from a network or a storage medium. For example, the storage medium may include one or more of the following: a hard disk, a random access memory (RAM), a read only memory (ROM), a memory of a distributed computing system, an optical disc (e.g., a compact disc (CD), a digital versatile disc (DVD), or a Blu-ray Disc (BDTM)), a flash memory device, a memory card, and the like.

[0125] Embodiments of the present invention can also be implemented by the following method, that is, by providing software (program) that performs the functions of the above embodiments to a system or apparatus through a network or various storage media, and the method of the computer or the central processing unit (CPU), the microprocessing unit (MPU) of the system or apparatus reading and executing the program.

[0126] Although the present disclosure has been described with reference to exemplary embodiments, it should be understood that the present disclosure is not limited to the disclosed exemplary embodiments. The scope of the appended claims should be given the broadest interpretation so as to cover all such modifications and equivalent structures and functions.

Claims

1. An image forming apparatus includes a plurality of sheet feeding cassettes, and the image forming apparatus includes: A control unit that, when the number of sheets discharged during the execution of a print job for printing image data reaches a predetermined value, controls to perform an interruption process of a correction job for a print correction block; and An acquisition unit that acquires color measurement data from the correction block; and wherein the control unit corrects the image data based on the color measurement data acquired by the acquisition unit, and wherein the control unit feeds the sheet on which the correction block is to be printed from the same sheet feeding cassette among the plurality of sheet feeding cassettes as the sheet feeding cassette for the page printed immediately before the interruption process.

2. The image forming apparatus according to claim 1, further comprising a storage unit configured to store information about a sheet feeding cassette for printing a page included in a print job, wherein, The control unit determines the sheet feeding cassette to be used for the correction job based on the information about the sheet feeding cassette stored in the storage unit.

3. The image forming apparatus according to claim 1, wherein, After determining the sheet feeding cassette to be used for the correction job, the control unit controls to print the correction block on the sheet fed from the determined sheet feeding cassette.

4. The image forming apparatus according to claim 1, wherein, The control unit controls to reflect the correction process on the print job, and wherein, after the correction job, the execution of the print job is resumed.

5. The image forming apparatus according to claim 1, further comprising a storage unit configured to store reference values of respective sheet information, wherein, The control unit generates a correction value for the correction process based on a reference value of the color measurement data of the correction block and the sheet information of the sheet on which the correction block is printed.

6. The image forming apparatus according to claim 5, wherein, A storage unit stores the correspondence between the sheet feeding cassette and the sheet information, and wherein, based on the correspondence, the control unit designates a reference value for generating the correction value according to the information about the sheet feeding cassette to be used for the correction job.

7. The image forming apparatus according to claim 1, further comprising a storage unit configured to store correction values of respective sheet information, wherein, The control unit performs the correction process by using the correction value of the sheet information of the sheet on which the correction block is printed.

8. The image forming apparatus according to claim 7, wherein, The storage unit stores the correspondence between the sheet feeding cassette and the sheet information, and wherein, based on the correspondence, the control unit designates a reference value for generating the correction value according to the information about the sheet feeding cassette to be used for the correction job.

9. An image forming apparatus includes a plurality of sheet feeding cassettes, and the image forming apparatus includes: A control unit that, when the number of sheets discharged during the execution of a print job for printing image data reaches a predetermined value, controls to perform an interruption process of a correction job for a print correction block; and An acquisition unit that acquires color measurement data from the correction block; and wherein the control unit corrects the image data based on the color measurement data acquired by the acquisition unit, and The image forming apparatus further includes a setting unit that sets either a first mode or a second mode, wherein the first mode is a mode in which the sheet feeding cassette to be used for the correction job is determined based on the information about the sheet feeding cassette for the page printed immediately before the interruption process, and The second mode is a mode in which the sheet feeding cassette to be used for the correction job is determined based on the information about the sheet feeding cassette for the pages printed from after the execution of the interruption process until the current interruption process.

10. A control method for an image forming apparatus, the image forming apparatus including a plurality of sheet feeding cassettes, the control method comprising: When the number of sheets discharged during the execution of a print job for printing image data reaches a predetermined value, control is performed to execute an interruption process of a correction job for a print correction block; Acquire color measurement data from the correction block; And Correct the image data based on the acquired color measurement data, Among them, the sheet on which the correction block is to be printed is fed from the same sheet feeding cassette among the plurality of sheet feeding cassettes as the sheet feeding cassette for the sheet of the page to be printed immediately before the interruption process.

Images