Image forming apparatus, control method thereof, and program

Abstract

To perform tone correction for a specified type of sheet as an objective.SOLUTION: An image formation device includes: an image formation part for forming an image on a sheet; and a detection part for detecting an image formed on a sheet. When page count printed from the start of a job of forming an image on a sheet reaches predetermined page count, the image formation device controls such that the image formation part forms a tone correction chart and receives a selection from a plurality of types of sheets as a sheet to be used for the tone correction chart.SELECTED DRAWING: Figure 16

Description

[Technical Field]

[0001] The present invention relates to a technique for suppressing color variations that occur during a print job. [Background technology]

[0002] Some image forming devices have a function to suppress image quality fluctuations during mass printing. One such technique involves forming a chart containing patches for gradation correction in the margins of a sheet and measuring the patches with a colorimetric sensor. Based on the colorimetric values, correction values ​​for gradation correction are created, and the correction values ​​are fed back to the image generation unit to perform gradation correction on subsequent pages. As an example of such a technique, Patent Document 1 discloses a technique in which reference values ​​and correction values ​​for correcting image quality fluctuations are set for each job, suppressing fluctuations within the job. Therefore, Patent Document 1 manages the reference values ​​and correction values ​​used for gradation correction on a print job-by-print job basis. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 06340920 Summary of the Invention [Problem to be solved by the invention]

[0004] When multiple pages of sheets with images formed on them are collected together to produce a deliverable, for example, multiple types of sheets may be used to form images within a single print job. In such cases, the quality required by the user may differ depending on the type of sheet. However, Patent Document 1 does not consider such cases where multiple types of sheets or different image qualities are used within a single job.

[0005] The present invention has been made in consideration of the above-mentioned conventional examples, When the number of pages printed from the start of a job for forming an image on a sheet reaches a predetermined number and there is no sheet of the type for which selection has been accepted among the remaining pages of the job, the image forming means does not form a gradation correction chart on the sheet of the type for which selection has been accepted, and when there is a sheet of the type for which selection has been accepted among the remaining pages of the job, the image forming means is controlled to form a gradation correction chart on the sheet of the type for which selection has been accepted. The purpose is to: [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, an image forming apparatus of the present invention has an image forming means that forms an image and a gradation correction chart on a sheet, a conveying means that conveys the sheet on which the image has been formed by the image forming means and the sheet on which the gradation correction chart has been formed, a detecting means that detects the gradation correction chart formed on the sheet conveyed by the conveying means, a receiving means that receives a selection of a sheet type to be used for forming the gradation correction chart from a plurality of sheet types, and a control means that controls the image forming means to form the gradation correction chart on a sheet of the type for which the selection has been received when the number of pages printed since the start of a job for forming an image on a sheet has reached a predetermined number, and the control means It is determined whether the image quality priority setting is set, and if the image quality priority setting is not set, controlling the image forming means not to form the gradation correction chart on the sheet of the type for which the selection has been accepted; When the image quality priority setting is set, the image forming means is controlled to form a gradation correction chart on a sheet of a type that is being supplied; When the number of pages printed since the job was started reaches the predetermined number, and there is a page to be printed on a sheet of the type for which the selection was accepted among the remaining pages of the job to be printed until the job is completed, the image forming means is controlled to form the gradation correction chart on a sheet of the type for which the selection was accepted. [Effects of the Invention]

[0007] According to the present invention, When the number of pages printed from the start of a job for forming an image on a sheet reaches a predetermined number and there is no sheet of the type for which selection has been accepted among the remaining pages of the job, the image forming means does not form a gradation correction chart on the sheet of the type for which selection has been accepted, and when there is a sheet of the type for which selection has been accepted among the remaining pages of the job, the image forming means is controlled to form a gradation correction chart on the sheet of the type for which selection has been accepted. It is possible. [Brief explanation of the drawings]

[0008] [Figure 1] A diagram explaining the configuration of a printing system [Figure 2]Block diagram illustrating the hardware configuration of a printing device [Figure 3] Block diagram illustrating the software configuration of a printing device [Figure 4A] Sequence diagram of margin insertion type printing process [Figure 4B] Sequence diagram of margin insertion type printing process [Figure 5] Sequence diagram of registration and deletion of reference and correction values [Figure 6] Flowchart of the deletion and registration process of the reference value and correction value [Figure 7] Screen transition diagram for paper change screen (paper source selection screen and paper type selection screen) [Figure 8A] A diagram showing an example of patch positions and sensor reading positions for real-time tone correction. [Figure 8B] A diagram showing an example of the print document transport direction, print surface, and sensor position. [Figure 8C] A diagram showing the reference value, measurement value, and correction value sample (plain paper 3) for gradation correction [Figure 8D] FIG. 10 is a diagram showing an example of a reference value management table and a correction value management table for gradation correction; [Figure 9] A diagram showing an example of the configuration of a print job [Figure 10] Block diagram explaining the hardware configuration of an information processing terminal [Figure 11] FIG. 10 is a diagram showing an example of a screen of an information processing terminal. [Figure 12] Flowchart of information processing terminal (print job generation and transmission) [Figure 13] FIG. 10 is a diagram showing an example of a UI for selecting paper for adjustment on an information processing terminal. [Figure 14] Sequence diagram of chart insertion type printing process (printing print data) [Figure 15] Sequence diagram of chart insertion type printing process (chart printing) [Figure 16] Flowchart for checking whether chart printing is necessary in the first embodiment [Figure 17] Flowchart for checking whether chart printing is necessary in the second embodiment [Figure 18] Flowchart for checking whether chart printing is necessary in the third embodiment DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention claimed. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0010] [First embodiment] As a first embodiment, an example will be described in which a color chart for tone correction is printed on a specified type of sheet each time the number of printed pages reaches a predetermined number (predetermined threshold) while a print job is being executed.

[0011] ●Configuration Fig. 1 is a diagram illustrating the configuration of a printing system (or image forming system) according to an embodiment of the present invention. As shown in Fig. 1, the printing system includes an information processing device 102 and a printing device (or image forming device) 101 connected via a LAN (local area network) 100. The printing device 101 is capable of printing a print job received from the information processing device 102.

[0012] The printing device 100 includes a paper feed unit 1011, an image forming unit 1012, an inspection unit 1013, a paper discharge unit 1014, and an operation unit 1015. The paper feed unit 1011 is equipped with multiple loading trays (also called paper feed stages), each of which can load sheets (also called print media) such as cut sheets of the same or different types or sizes. For example, one tray can load plain paper for normal quality printing, and another tray can load coated paper for high quality printing. The tray from which paper is to be loaded is specified, for example, by the print job, and sheets taken from the specified tray are transported to the image forming unit 1012. The tray designation can be changed even within a single print job.

[0013] Each tray is equipped with a sensor (image sensor) for detecting the size of the sheet placed thereon. The detection target may be the size of the sheet itself, or the position of the frame for placing the sheet. Attributes of the placed sheet other than the size (called the sheet type) may be detected by the sensor, or may be set by the operator via the operation unit 1015 or the like. The size may also be specified by the operator. This allows the image forming apparatus 101 to identify the size and type of the placed sheet for each tray.

[0014] The image forming unit 1012 forms an image generated from print data specified in a print job on a sheet conveyed from the paper feed unit 1011. In this example, the image forming unit 1012 may be, for example, an electrophotographic image forming unit that forms an image using toner as a coloring agent. The image forming unit 1012 develops an electrostatic latent image formed on a photosensitive member with toner, transfers it to a sheet, and heats and fixes it. In the case of a color image, a toner image for each color component is transferred to a sheet and fixed to form a color image.

[0015] The printing device 101 performs color conversion (basic color conversion) to convert color components specified in image data into color components of toner. Because basic color conversion does not always result in ideal colors, color correction (also called gradation correction) is also performed using correction information. Color correction is performed, for example, according to the type of sheet. This is because colors may appear differently depending on the type of sheet. Furthermore, if color misalignment occurs, appropriate correction may be performed to eliminate the color misalignment. To appropriately correct color misalignment, the printing device 101 has a color correction function. The color correction function has correction information for each sheet type, for example, and measures the color values ​​of gradation patches formed on the sheet. The difference between the color values ​​that should be represented (reference information) and the measured color values ​​(measurement information) is reflected in the correction information.

[0016] For color correction, the sheet on which an image has been formed by the image forming unit 1012 is transported to the inspection unit 1013, where the color can be read by a color measurement sensor while the sheet is being transported. In this example, the object of color measurement is a gradation correction chart (also called a color chart) formed on the sheet, and its position, gradation, etc. may be predetermined. The color measurement sensor is provided at a position corresponding to the gradation correction chart and measures the color values ​​of the gradation correction chart. In this example, the inspection unit 1013 targets only one side, but it may also be configured to measure both sides of the gradation correction chart in parallel. Note that one of two methods may be selected as the method for printing the color measurement chart.

[0017] The first method is to insert a gradation correction chart while a job is being executed. In this method, a sheet with only a gradation correction chart formed on it is inserted in the middle of the job and becomes the subject of inspection. The process of printing the gradation correction chart may be a job that interrupts the original print job, and this job may be called, for example, an interrupt job. Because a sheet with an image formed by the interrupt job interrupts the print job, the inspection unit 1013 may be provided with a paper output tray for ejecting the inserted sheet with the measured gradation correction chart formed on it. Once the inserted sheet is ejected here, only the sheets related to the print job are transported to the subsequent paper output unit 1014. The first method is sometimes called an interrupt mode.

[0018] The second method is to form a gradation correction chart in the margin of a sheet on which an image related to a print job is formed. With this method, a gradation correction chart can be formed on each sheet and colorimetrically measured. To enable selection between the first method and the second method, the position of the gradation correction chart on the sheet may be fixed regardless of the method. In this case, the position of the gradation correction chart will be a position equivalent to the margin, even in the first method. The second method is sometimes called a margin utilization mode.

[0019] The sheet that has passed through the inspection unit 1013 is transported to the paper discharge unit 1014 and discharged to a specified paper discharge tray. If the mechanism switches the discharge destination by, for example, switching a guide claw provided at a branch point of the transport path, the guide claw can be driven to switch the path once the leading edge of the sheet has passed the branch point. This makes it possible to switch the paper discharge tray on a sheet-by-sheet basis. For example, if a sheet for forming a gradation correction chart is inserted in a print job, the paper discharge unit 1014 can discharge the inserted sheet for the gradation correction chart to a paper discharge tray separate from the sheets of the print job.

[0020] The operation unit 1015 has an operation panel that allows an operator to perform various operations and monitoring. The printing system may be configured so that the operations and monitoring that can be performed by the operation unit 1015 can be performed by the information processing device 102. The operations may include, for example, an instruction to insert a chart sheet every predetermined number of pages (or every predetermined number of sheets).

[0021] ●Control system hardware FIG. 2 is a block diagram illustrating the hardware configuration of the control system of the printing device 101 according to this embodiment. The printing device 101 has a printing function for printing images on sheets. While this embodiment uses a printing device as an example, the printing device may also be a printing device such as an MFP (Multi-Function Peripheral) that includes a scanner or fax function. A control unit 2100 including a CPU (Central Processing Unit) 2101 controls the overall operation of the printing device 101. The CPU 2101 loads programs stored in a ROM (Read Only Memory) 2102 or storage 2104 into a RAM 2103 and executes the programs to perform various controls, such as print control and read control. The ROM 2102 stores control programs, boot programs, and the like that can be executed by the CPU 2101. The RAM (Random Access Memory) 2103 is the main memory of the CPU 2101 and is used as a work area or a temporary storage area for loading various control programs. The storage 2104 stores print data, image data, various programs, and various setting information. The storage 2104 may be nonvolatile and have a file-based management structure. In this embodiment, the storage 2104 is assumed to be an auxiliary storage device such as an HDD (Hard Disk Drive), but a nonvolatile memory such as an SSD (Solid State Drive) may also be used. In the printing device 101 according to this embodiment, a single CPU 2101 executes the processes shown in the flowcharts described below using a single memory (RAM 2103), but other configurations are also possible. For example, multiple CPUs, RAMs, ROMs, and storages may cooperate to execute the processes shown in the flowcharts described below. Furthermore, some of the processes may be executed using hardware circuits such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).

[0022] An operation unit interface (I / F) 2105 connects an operation unit 2106 and the control unit 2100. The operation unit 2106 is provided with a display unit with a touch panel function, various hard keys, etc., and functions as a display unit that displays information and a reception unit that receives instructions from the user. The operation unit 2106 is the same as the operation unit 1015 shown in FIG. 1.

[0023] The image processing unit 2107 has the functionality of a RIP (Raster Image Processor) that converts a print job received via the communication unit I / F 2108 and generates image data to be used for printing. The image processing unit 2107 can also perform resolution conversion and correction of the image data obtained by converting the print job. Note that in this embodiment, it is assumed that the image processing unit 2107 is implemented using a hardware circuit (such as an ASIC or FPGA), but this is not limited to this. For example, the printing device 101 may further include a processor for image processing, and the processor may execute an image processing program to perform image processing and print data expansion. In this case, the processor and the CPU 2101 cooperate to realize the flowcharts described below. Furthermore, the CPU 2101 may be configured to execute a program for image processing to perform image processing and print data expansion. Image processing may also be performed using any combination of these.

[0024] The printing unit (printer engine) 2109 prints an image on a sheet fed from a paper feed cassette (not shown) based on image data generated by the image processing unit 2107. The printing method of the printing unit 2109 may be an electrophotographic method as described in FIG. 1, but other printing methods such as an inkjet method or a thermal transfer method may also be applied. The paper feed unit 1011 to the paper discharge unit 1014 shown in FIG. 1 are included in the printing unit 2109. However, the colorimetric sensor of the inspection unit 1013 corresponds to the colorimetric unit 2110 described below.

[0025] The colorimetric unit 2110 is provided in the inspection unit 1013 in Fig. 1. That is, it is located downstream of the paper transport path of the printing unit 2109, and uses a CIS color sensor to measure the color of the gradation correction patches of each color of the gradation correction chart formed on the printed paper, thereby obtaining colorimetric data. The paper sizes and paper types that can be measured by this colorimetric unit 2110 are limited. The colorimetric unit 2110 is also called an inline sensor.

[0026] The control unit 2100 is connected to the LAN 100 via a communication unit I / F 2108. The communication unit I / F 2108 receives a print request (print job) from an information processing apparatus on the LAN 100.

[0027] In this embodiment, the above configuration example will be described as an example of a printing system, but the present invention is not limited to this. It is sufficient that at least one information processing device and one printing device are connected to each other so that they can communicate with each other via a network. The network may be wireless or wired.

[0028] ●Software FIG. 3 is a block diagram illustrating the software configuration of the printing device 101 according to this embodiment.

[0029] When a job is input from the information processing apparatus 102 , the print job generation unit 301 generates a print job and registers it in the job control unit 303 .

[0030] The job control unit 303 notifies the page control unit 304 of the start of processing for all pages included in the registered print job, starting with page 1, to start page processing. When the page control unit 304 notifies the job control unit 304 that processing for the next page can begin, the job control unit 303 repeats this process of notifying the page control unit 304 of the start of processing for the next page. Then, when the page control unit 304 notifies the job control unit 301 that processing has ended for all pages, the job control unit 303 notifies the print job generation unit 301 that the job has ended.

[0031] The page control unit 304 controls the processing of each page upon receiving a notification of the start of page processing from the job control unit 303. The processing of each page includes the generation of an image to be formed on each page.

[0032] The data reception control unit 302 receives the PDL data transmitted from the information processing device 102 via the communication unit I / F 2108 .

[0033] The PDL analysis unit 305 analyzes the received PDL data and converts it into intermediate data, and the RIP control unit 306 rasterizes the intermediate data and converts it into image data in bitmap format.

[0034] The image generation unit 307 generates a corrected print image by reflecting correction information for the sheet (hereinafter also referred to as paper) used for printing on the generated bitmap image data. Then, the print image is transferred to a patch synthesis unit 309 of the engine control unit 308. The image generation unit 307 controls the image processing unit 2107 in FIG. 2.

[0035] The engine control unit 308 includes a patch synthesis unit 309, a correction information storage unit 310, a reference information storage unit 311, a colorimetry sensor control unit 312, a paper feed stage management unit 313, a paper feed control unit 314, and a print control unit 315. The colorimetry sensor control unit 312 controls the colorimetry unit 2110. The patch synthesis unit 309, the correction information storage unit 310, the reference information storage unit 311, the paper feed stage management unit 313, the paper feed control unit 314, and the print control unit 315 control the print unit 2109. In particular, the paper feed control unit 314 controls the paper feed unit 1011. The print control unit 315 may control the transport of sheets from the inspection unit 1013 to the paper discharge unit 1014, in addition to the image formation by the image forming unit 1012.

[0036] The patch composition unit 309 combines a gradation correction chart (including predetermined gradation patches) with the print image so that the gradation correction chart is formed in addition to the image formed based on the corrected print image received from the image generation unit 307. It then instructs the print control unit 315 to print the combined image. In interrupt mode, the image combined with the gradation correction chart may be a blank image. Alternatively, composition may not be performed using only the gradation correction chart. The gradation patches may be converted into image data in advance using the basic color conversion used for image generation and saved. Using such gradation patches, the difference between reference information indicating the color that should be represented and measurement information indicating the color measured by a sensor can be identified as correction information. For example, by reflecting the correction information in the color-converted image data and performing color correction, an image can be formed on the sheet with the desired color. The correction value may be simply added for each density. Since gradation patch samples are prepared for each representative density, the densities between the samples may be determined, for example, by linear interpolation.

[0037] The paper feed control unit 314 controls the paper feed tray according to the instructions of the print job, and transports and supplies the paper stored in the paper feed tray. Note that printing of the gradation correction marks in interrupt mode may be included as part of the print job. In that case, the paper specification for the interrupt mode is also specified by the print job. Alternatively, an interrupt job that interrupts the print job may be generated, and the gradation correction marks may be printed by that job. In that case, the paper specification for the interrupt mode may be specified by the interrupt job.

[0038] The print control unit 315 prints the print image with the gradation patches combined onto paper supplied by the paper feed control unit 314 and ejects the paper. In this embodiment, an image is formed on paper based on image data to which gradation correction chart information (gradation patches) has been added as necessary.

[0039] The colorimetric sensor control unit 312 controls the colorimetric unit 2110 to measure the gradation correction marks formed on the paper, and acquires colorimetric data.

[0040] The reference information storage unit 311 stores, for each paper type set in a paper feed tray, reference information generated based on colorimetric data acquired by the colorimetric sensor control unit 312. In this embodiment, correction information is generated to correct the color (tone) of the image so that the measurement information of the gradation patch matches the reference information.

[0041] The correction information storage unit 310 stores correction information obtained by comparing the reference information stored in the reference information storage unit 311 with the colorimetric data acquired by the colorimetric sensor control unit 312 for each paper type set in the paper feed tray.

[0042] The paper feed tray management unit 313 manages information about the sizes and types of paper set in all paper feed trays provided in the printing device 101. In addition, in response to a paper registration request from the UI control unit 316, the paper feed tray management unit 313 clears the reference information stored in the reference information storage unit 311 for the paper type to be removed for replacement. Furthermore, if the correction information storage unit 310 stores correction information for the paper type to be removed for replacement, the correction information is also cleared.

[0043] When a user operates the operation unit 2106 to set paper information for a paper feed tray, the UI control unit 316 requests the paper feed tray management unit 313 to register the paper. In addition, the UI control unit 316 displays information about the paper whose registration has been completed on the operation unit 2106. The UI control unit 316 is responsible for controlling the operation unit 2106.

[0044] ●Basic sequence Next, we will explain the basic sequence of the printing process, in which gradation correction patches are formed on the output paper of a print job, measured in real time by a colorimetric sensor, and the correction values ​​are continuously fed back to subsequent pages. Hereafter, this control will be called real-time gradation correction.

[0045] There are two types of real-time gradation correction: a margin utilization type that uses the margins of the output paper to print patches, and a chart insertion type that inserts special paper and prints patches when the margins of the output paper cannot be used. With the margin utilization type, patches are printed on each page in the margins of the print data entered by the user, and feedback correction is performed. This corresponds to the margin utilization mode described above. On the other hand, with the chart insertion type, patches are printed on special paper at intervals set in advance in the printing device 101, and feedback correction is performed. This corresponds to the interrupt mode described above. When entering a print job, the user instructs the printing device whether to perform real-time gradation correction as the margin utilization type or the chart insertion type.

[0046] Printing process using white space First, the basic operation sequence of margin-utilizing printing processing will be described using Figures 4A and 4B. This sequence is realized by the CPU 2101 of the printing device 101 reading a program stored in ROM 2102 into RAM 2103 and executing it. Note that Figures 4A and 4B show a series of sequences divided into two, and the boxes marked "LOOP" in Figures 4A and 4B are not independent loops, but represent a single loop that has been divided due to size constraints of the figures.

[0047] The job generation unit 301 receives data from the I / F and generates a print job. The job generation unit 301 registers the generated job in the job control unit 303 (S4001). The job control unit 303 determines the execution order of the registered jobs and starts sequential processing (S4002). The processing started in S4002 is repeated for each page until the final page is reached.

[0048] The job started by the job control unit 303 notifies the page control unit 304 of the start of processing the Nth page (S4003). When the page control unit 304 receives the start of processing the Nth page from the job control unit 303, it queries the paper feed tray management unit 313 as to which paper feed tray to use for feeding paper of the paper size and paper type specified for the page (S4004). The paper feed tray management unit 313 determines which paper feed tray to use for feeding paper from based on the specified paper size and paper type (S4005) and returns the result to the page control unit 304.

[0049] The page control unit 304 instructs the paper feed control unit 314 to feed paper from the paper feed tray determined by the paper feed tray management unit 313 (S4006). The paper feed control unit 314 feeds paper from the specified paper feed tray in accordance with the paper feed instruction from the page control unit 304 (S4007) and notifies the page control unit 304 of the paper feed result (S4008). When the page control unit 304 receives a normal paper feed result from the paper feed control unit 314, it notifies the job control unit 308 that it is now possible to start processing the next page (S4009). Furthermore, when the page control unit 304 receives a normal paper feed result from the paper feed control unit 314, it instructs the image generation unit 307 to generate and transfer a print image (S4010). At this time, the page control unit 304 notifies the image generation unit 307 of the paper feed tray from which paper was fed, the paper size, and the paper type.

[0050] When the image generation unit 307 receives an instruction to generate and transfer a print image, it requests correction information from the correction information storage unit 310 based on the notified information (S4011). The correction information storage unit 310 searches for correction information corresponding to the passed information stored in RAM 2103 (S4012). If the correction information storage unit 310 detects the corresponding correction information, it notifies the image generation unit 307 of the correction information (S4013). The image generation unit 307 generates a print image using the correction information notified by the image information storage unit 310 (S4014). On the other hand, if the correction information storage unit 310 cannot detect correction information corresponding to the passed information, it notifies the image generation unit 307 that there is no correction information (S4015). If there is no correction information, the image generation unit 307 generates a print image without correction (S4016). The image generation unit 307 transfers the generated print image and the paper feed tray, paper size, and paper type information notified by the page control unit 304 to the patch synthesis unit 309 (S4017).

[0051] The patch composition unit 309 composites a gradation adjustment chart (gradation patch) into the margins of the print image transferred by the image generation unit 307 (S4018). Next, the patch composition unit 309 transmits the generated composite image and the paper feed tray, paper size, and paper type information notified by the image generation unit to the print control unit 315 and instructs it to print (S4019). The print control unit 315 prints the received image (the image with the gradation adjustment mark information composited) on paper supplied by the paper feed control unit 314 (S4020). When printing is complete, the print control unit 315 notifies the page control unit 304 and the colorimetric sensor control unit 312 that printing is complete (paper ejection is complete) (S4021). The notification of printing completion (paper ejection is complete) includes information such as the paper feed tray, paper size, and paper type.

[0052] When the page control unit 304 receives a notification of completion of printing (paper discharge) from the print control unit 315, it notifies the job control unit 303 of the completion of processing the Nth page (S4022).

[0053] Meanwhile, when the colorimetric sensor control unit 312 receives a printing completion (paper ejection completion) notification from the print control unit 315, it performs colorimetry of the gradation adjustment chart (gradation patches) printed in S4020 (S4023). Next, it associates the colorimetry results with information such as the paper feed tray, paper size, and paper type notified by the print control unit 315, and notifies the reference information storage unit 311 (S4024).

[0054] The reference information storage unit 311 searches the RAM 2103 to determine whether a reference value corresponding to the information notified by the colorimetric sensor control unit 312 is stored therein (S4025). If a reference value corresponding to the notified information is stored, a correction value is calculated from the stored reference value and the colorimetric result notified by the colorimetric sensor control unit 312 (S4026). Next, the reference value information storage unit 311 notifies the correction information storage unit 310 of the calculated correction value (S4027). The correction information storage unit 310 stores the content notified by the reference value information storage unit 311 as correction information (S4028).

[0055] If the reference value is not saved in S4025, the reference value information saving unit 311 saves the information notified from the colorimetric sensor control unit 312 (colorimetric result, paper feed tray, paper size, paper type, etc.) as a reference value in RAM 2103 (S4029).

[0056] Here, the processing from S4003 to S4025 is expressed as a loop because it is executed for all pages of the print job registered in the job control unit 303. The start of processing for each page shown in S4003 can be issued when a notification of next page processing start readiness is received in S4009.

[0057] When the job control unit 303 receives the completion of processing of the Nth page, it determines whether the Nth page is the final page of the print job (S4030). If the job control unit 303 determines that it has received the completion from the final page, it notifies the print job generation unit 301 of the end of the job (S4031).

[0058] ●Chart insertion type printing process Next, the basic operation sequence of chart insertion type printing processing will be described using Figures 14 and 15. Figure 14 shows the sequence for printing print data as an image, and Figure 15 shows the sequence for printing the correction chart to be inserted. This sequence is realized by the CPU 2101 of the printing device 101 reading a program stored in ROM 2102 into RAM 2103 and executing it.

[0059] Printing data printing process First, the sequence for printing print data will be described with reference to Fig. 14. The job generation unit 301 receives data from the I / F and generates a print job. The job generation unit 301 registers the generated job in the job control unit 303 (S1401). The job control unit 303 determines the execution order of the registered jobs and starts sequential processing (S1402). The steps from S1403 onwards are repeated for each page until the final page.

[0060] When the job execution is processed, the job control unit 303 notifies the page control unit 304 of the start of processing the Nth page (S1403). When the page control unit 304 receives the start of processing the Nth page from the job control unit 303, it inquires of the paper feed tray management unit 313 about which paper feed tray to use for feeding paper of the paper size and paper type specified for the page (S1404). The paper feed tray management unit 313 determines which paper feed tray to use for feeding paper from based on the specified paper size and paper type (S1405) and returns the result to the page control unit 304. The page control unit 304 instructs the paper feed control unit 314 to feed paper from the paper feed tray determined by the paper feed tray management unit 313 (S1406). The paper feed control unit 314 feeds paper from the specified paper feed tray in accordance with the paper feed instruction from the page control unit 304 (S1407) and notifies the page control unit 304 of the paper feeding result (S1408). When the page control unit 304 receives a normal paper feed result from the paper feed control unit 314, it notifies the job control unit 308 that it is now possible to start processing the next page (S1409).

[0061] Furthermore, when the page control unit 304 receives a normal paper feed result from the paper feed control unit 314, it instructs the image generation unit 307 to generate and transfer a print image (S1410). At this time, the page control unit 304 notifies the image generation unit 307 of the paper feed tray from which the paper was fed, the paper size, and the paper type. Upon receiving the instruction to generate and transfer a print image, the image generation unit 307 requests correction information for the corresponding print medium, particularly the paper type, from the correction information storage unit 310 based on the notified information (S1411). The correction information storage unit 310 searches the RAM 2103 to see if correction information corresponding to the received information is stored therein (S1412).

[0062] If the correction information storage unit 310 detects corresponding correction information, it notifies the image generation unit 307 of the correction information (S1413). The image generation unit 307 uses the correction information notified by the image information storage unit 310 to generate a print image (S1414). On the other hand, if the correction information storage unit 310 cannot detect correction information corresponding to the passed information, it notifies the image generation unit 307 that there is no correction information (S1415). If there is no correction information, the image generation unit 307 generates a print image without correction (S1416).

[0063] The image generation unit 307 sends the generated print image and the paper feed tray, paper size, and paper type information notified by the page control unit 304 to the print control unit 315 and instructs it to print (S1417). The print control unit 315 prints the received image on paper supplied by the paper feed control unit 314 (S1418). The image printed here does not include gradation adjustment mark information. When printing is complete, the print control unit 314 increments a counter and stores the count in the RAM 2103 (S1419). Furthermore, the print control unit 315 notifies the page control unit 304 that printing is complete (paper ejection is complete) (S1420). The notification of printing completion (paper ejection is complete) includes information such as the paper feed tray, paper size, and paper type. When the page control unit 304 receives the notification of printing completion (paper ejection is complete) from the print control unit 315, it notifies the job control unit 303 that processing of the Nth page is complete (S1421). When the job control unit 303 receives the completion of processing of the Nth page, it determines whether the Nth page is the final page of the print job (S1422). If the job control unit 303 determines that it has received the completion from the final page, it notifies the print job generation unit 301 of the end of the job (S1423).

[0064] Printing of gradation correction chart Next, the sequence for printing the chart to be inserted will be described with reference to FIG. 15. Each time the printing process is completed, the print control unit 315 checks whether or not chart printing is necessary (S1501). More specifically, it is determined whether or not the counter value counted up in S1419 has reached the chart insertion interval set in advance in the printing device 101. Here, for example, the step of S1501 may be executed following S1419 in FIG. 14. The processing procedure of S1501 will be described later with reference to FIG. 16.

[0065] If the print control unit 315 determines that the chart insertion interval has been reached, it performs processing from S1502 onwards. The print control unit 315 instructs the print job generation unit 301 to execute a job for inserting a chart (S1502). This instruction may include information such as the current paper feed tray, paper size, and paper type, as well as information that the job is for inserting a chart. Details of the process by which the user selects adjustment paper will be described later using FIG. 12.

[0066] When the job generation unit 301 receives an instruction to execute a chart insertion job, it determines whether the printed and ejected paper is the final page of the print job. If it is the final page, there is no point in performing color correction for that job, so the job ends without any further processing. On the other hand, if it is not the final page, a print job is generated based on an instruction from the print control unit 315. At this time, the type of sheet used in the job is the type of sheet specified as the adjustment sheet in the procedure shown in FIG. 12 (described later). For example, if the job generation unit 301 receives paper feed tray information for each sheet type from the paper feed tray control unit 314 in advance, it can generate a chart insertion job by specifying the paper feed tray on which the adjustment sheet is placed. The job generation unit 301 registers the generated job in the job control unit 303 (S1503). The job control unit 303 determines the execution order of the registered jobs and starts processing them sequentially (S1504). The job started by the job control unit 303 notifies the page control unit 304 of the start of processing (S1505). This notification includes information such as the paper feed tray to be used, paper size, paper type, etc., as well as information that this is an interrupt job for inserting a chart. Upon receiving the processing start notification from the job control unit 303, the page control unit 304 instructs the paper feed control unit 314 to feed paper from the paper feed tray notified by the page control unit 304 (S1506). The paper feed control unit 314 feeds paper from the instructed paper feed tray in accordance with the paper feed instruction from the page control unit 304 (S1507), and notifies the page control unit 304 of the paper feed result (S1508).

[0067] When the page control unit 304 receives a normal paper feed result from the paper feed control unit 314, it instructs the image generation unit 307 to generate and transfer a print image (S1509). At this time, the page control unit 304 notifies the image generation unit 307 of the paper feed tray from which paper was fed, the paper size, the paper type, and information that this is a print job for inserting a chart. When the image generation unit 307 receives the instruction to generate and transfer a print image, it transfers the print image for inserting the chart and the paper feed tray, paper size, and paper type information notified by the page control unit 304 to the patch synthesis unit 309 (S1510). Because only an adjustment patch image is printed on the chart to be inserted, the print image generated by the image generation unit 307 here is a blank image.

[0068] The patch composition unit 309 composites a gradation adjustment chart (gradation patch) into the margin of the print image transferred by the image generation unit 307 (S1511). The patch composition unit 309 may acquire correction information (correction values) for the type of paper on which the gradation patches will be printed from the correction information storage unit 310 and perform color correction on the gradation patches before compositing the images. Next, the patch composition unit 309 transmits the generated composite image and the paper feed tray, paper size, and paper type information notified by the image generation unit to the print control unit 315 and instructs it to print (S1512). The print control unit 315 prints the received image (the image with the gradation adjustment mark information composited) on paper supplied by the paper feed control unit 314 (S1513). When printing is complete, the print control unit 315 notifies the page control unit 304 and the colorimetric sensor control unit 312 that printing is complete (paper discharge is complete) (S1514). The notification of printing completion (paper ejection completion) includes information such as the paper feed tray, paper size, paper type, etc. When the page control unit 304 receives the notification of printing completion (paper ejection completion) from the print control unit 315, it notifies the job control unit 303 of the completion of processing (S1515).

[0069] Meanwhile, when the colorimetric sensor control unit 312 receives a printing completion (paper ejection completion) notification from the print control unit 315, it performs colorimetry of the gradation adjustment chart (gradation patches) printed in S1513 (S1516). Next, it associates the colorimetry results with information such as the paper feed tray, paper size, and paper type notified by the print control unit 315, and notifies the reference information storage unit 311 (S1517). The reference information storage unit 311 searches the RAM 2103 to see if a reference value corresponding to the information notified by the colorimetric sensor control unit 312 is stored therein (S1518).

[0070] If a reference value corresponding to the notified information has been saved, the reference information saving unit 311 calculates a correction value from the saved reference value and the colorimetry result notified from the colorimetry sensor control unit 312 (S1519). Next, the reference value information saving unit 311 notifies the correction information saving unit 310 of the calculated correction value (S1520). The correction information saving unit 310 saves the content notified from the reference value information saving unit 311 as correction information (S1521). If the reference value has not been saved in S1518, the reference value information saving unit 311 saves the information notified from the colorimetry sensor control unit 312 (colorimetry result, paper feed tray, paper size, paper type, etc.) in the RAM 2103 as a reference value (S1522). Upon receiving the notification of completion of processing, the job control unit 303 notifies the print job generating unit 301 of the end of the job (S1523).

[0071] ●Chart printing necessity check process (S1501) Here, the chart printing necessity check process of S1501 will be described. FIG. 16 is a flowchart of the chart printing necessity check process in this embodiment. First, it is determined whether the number of printed sheets counted in S1419 has reached a threshold value (S1601). Note that the number of sides may be counted; for example, one double-sided sheet may be counted as two. Considering that the greater the amount of printing, the more likely changes over time are to occur, it is reasonable to count the number of sides. If the number of printed sheets has reached the threshold value, the counted number of printed sheets is reset to 0 (S1602). Then, an instruction to execute a chart insertion job is sent to the print job generation unit 301 (S1502).

[0072] This procedure allows for the formation of color-corrected color patches on a pre-specified type of sheet using correction values ​​corresponding to that type, in a setting where a color correction chart is printed every specified number of sheets.

[0073] 15 may be performed by, for example, the job control unit 303 rather than by the print control unit 315. In that case, it is desirable that the job control unit 303 also count the number of printed sheets.

[0074] ● Clearing and updating reference information and correction information Next, a sequence for clearing the reference information and correction information will be described with reference to Fig. 5. This sequence is realized by the CPU 2101 of the printing apparatus 101 reading a program stored in the ROM 2102 into the RAM 2103 and executing it.

[0075] When the printing device 101 forms an image on paper, the characteristics vary depending on the paper type, so in order for the printing device 101 to perform gradation correction correctly, it is necessary to store reference information for each paper type. The printing device 101 supports many paper types, but the paper that will actually be used must be set in a paper feed tray, so the reference information storage unit 311 only stores reference information for the paper type set in the paper feed tray. Therefore, when the user sets new paper in a paper feed tray of the printing device 101, the reference information and correction information for the paper type that will be removed for replacement are cleared.

[0076] In S5001, the user operates the UI screen of the printing device 101 and selects a paper feed tray setting screen. In S5002, upon receiving an operation from the user, the UI control unit 316 of the printing device 101 obtains information on the size and type of paper set in all paper feed trays provided in the printing device 101 from the paper feed tray management unit 313. In S5003, the UI control unit 316 displays the information obtained in S5002 on the UI screen. An example screen is shown in FIG. 7(a). In S5004, the user selects the paper feed tray for which they want to change the paper from the UI screen of the printing device 101. In S5005, upon receiving an operation from the user, the UI control unit 316 of the printing device 101 displays on the UI screen a list of paper types that can be set for the selected paper feed tray. An example screen is shown in FIG. 7(b).

[0077] In S5006, the user selects the paper type to be changed from the UI screen of the printing apparatus 101. In S5007, upon receiving an operation from the user, the UI control unit 316 of the printing apparatus 101 requests the paper feed tray management unit 313 to register the paper feed tray and paper type selected by the user. In S5008, the paper feed tray management unit 313 updates the information stored in the reference information storage unit 311 and the correction information storage unit 310. A detailed flow will be described later using FIG. 6A. If the paper feed tray management unit 313 determines that it is necessary to clear the reference information and correction information based on the flowchart of FIG. 6A, it performs clearing processing in S5009 and S5010. In S5009, the paper feed tray management unit 313 clears the reference information for the paper type to be removed for replacement that was stored in the reference information storage unit 311. Furthermore, in S5010, the paper feed tray management unit 313 determines whether correction information for the paper type to be removed for replacement exists in the correction information storage unit 310, and if so, clears the correction information.

[0078] After completing the series of processes in S5008, the paper feed tray management unit 313 performs registration processing for the paper type specified by the user in S5011. In S5012, the paper feed tray management unit 313 notifies the UI control unit 316 of the completion of registration, and in S5013, the UI control unit 316 updates the UI screen with information about the registered paper type.

[0079] 6(a) and 6(b) show the processing flow of the paper feed management unit 313 in response to a change in the paper type registered in each paper feed tray of the printing device 101. Fig. 6(a) is a flowchart for explaining the clearing of the reference information and correction information for each paper type, and Fig. 6(b) is a flowchart for explaining the registration of the reference information and correction information for each paper type.

[0080] First, Fig. 6A will be described, which shows the processing flow of the paper feed management unit 313 when a request is made to register the paper feed tray and paper type selected by the user in S5007 of Fig. 5 described above.

[0081] In S601, the paper feed tray management unit 313 receives a request from the UI control unit 316 to register the paper feed tray and paper type selected by the user. In S602, the paper feed tray management unit 313 determines whether there has been a change in the paper type. If there has been no change (if the same type is being re-registered), the processing ends; if there has been a change, the process proceeds to S603. In S603, the paper feed tray management unit 313 checks whether the same paper as that set in the paper feed tray to be changed in S601 is set in another paper feed tray. If the same paper is set in another paper feed tray, the process proceeds to S605; if not, the process proceeds to S604. In S604, the paper feed tray management unit 313 will no longer use the paper type before the change in all paper feed trays, so it deletes the reference value and correction value information (TBL881 and TBL883, described later) for the paper in question from the reference information storage unit 311 and the correction information storage unit 311, and then proceeds to S605. In step S605, the paper feed tray management unit 313 deletes the record of the paper type information of the paper feed tray whose settings are to be changed from the reference value management table and the correction value management table.

[0082] Next, Fig. 6(b) will be described. Fig. 6(b) shows the processing flow of the reference information storage unit 311 and the correction information storage unit 310 when a notification of the colorimetry result is received from the colorimetry sensor control unit 312 in S4024 of Fig. 4B described above. It also shows the processing flow of the reference information storage unit 311 and the correction information storage unit 310 when a notification of the colorimetry result is received from the colorimetry sensor control unit 312 in S1517 of Fig. 15.

[0083] In S620, the reference information storage unit 311 acquires the colorimetry results from the colorimetry sensor control unit 312. In S621, the reference information storage unit 311 determines whether a record of the paper feed tray linked to the colorimetry results notified by the colorimetry sensor control unit 312 is registered in the reference value management table. If not registered, the process proceeds to S622, and if registered, the process proceeds to S626. In S622, the reference information storage unit 311 determines whether a paper type linked to the colorimetry results notified by the colorimetry sensor control unit 312 is registered for another paper feed tray in the reference information management table. If not registered, the process proceeds to S623. In S623, the reference information storage unit 311 saves the colorimetry results notified by the colorimetry sensor control unit 312 as a reference value (TBL881, described below). Next, in S624, the reference information storage unit 311 adds to the reference value management table a record of the paper feed tray linked to the colorimetry result notified from the colorimetry sensor control unit 312, performs link processing that references the reference value saved in S623, and then ends.

[0084] On the other hand, if in S622 the reference information storage unit 311 confirms that the paper type linked to the colorimetry results notified by the colorimetry sensor control unit 312 is registered for another paper feed tray in the reference information management table, the process proceeds to S625. In S625, the reference information storage unit 311 copies the record for the same paper type that was already registered in the reference information management table as the record for the paper feed tray linked to the colorimetry results notified by the colorimetry sensor control unit 312 to the reference information management table. This means that the reference values ​​for this paper type are saved. The process then proceeds to S626.

[0085] In S626, the reference information storage unit 311 calculates a correction value from the measurement value and the reference value, and notifies the calculated correction value to the correction information storage unit 310. Then, in S627, the correction information storage unit 310 stores the content notified by the reference information storage unit 311 as correction information, and the process ends.

[0086] ●Registering paper types 7, the screen for registering the paper type for the paper feed tray of the printing apparatus 101 will be described in conjunction with the procedure already described in FIG.

[0087] 7A shows the paper feed tray setting screen displayed by the UI control unit 316. When the user invokes the paper feed tray setting screen (S5001), the UI control unit 316 queries the paper feed tray management unit 313 for current paper feed tray setting information (S5002), and the results are displayed on the screen 700 (S5003). The user selects the paper feed tray for which the paper type is to be set on screen 700. In this embodiment, selection buttons 701 to 704 are assigned to four paper feed trays. After selecting a specific paper feed tray, the user presses setting button 705 to set the paper type (S5004), and calls up paper type setting screen 710 shown in FIG. 7(b) (S5005).

[0088] On the paper type selection screen 710, the user selects one that matches the paper type that has been or will be set in the paper feed tray selected on screen 700. In this case, Plain Paper 1 is replaced with Plain Paper 3 (S5006), and the user presses the OK button 708 to return to screen 700. After the user confirms that the paper type has been changed, the user presses the OK button 706. The UI control unit 316 notifies the paper feed tray management unit 313 of the user's settings (S5007) and requests registration (S5008).

[0089] Tone patches and correction tables Next, the management table (or correction table) for storing the tone correction chart (tone patch) and correction values ​​in this embodiment will be described with reference to FIGS. 8A to 8D.

[0090] FIG. 8A shows an example of an output of a gradation correction chart (gradation patch) 800 for the purpose of gradation correction. Patches required for real-time multi-tone correction are printed in a margin defined inside the printing paper 800 but outside the paper's guaranteed print area 801. The guaranteed print area is the portion that will become the final product, and is an area in which printing of the user's image is guaranteed. Meanwhile, outside the guaranteed print area, there is also an area where an image can be formed, but it is assumed that this area will be cut and removed from the final product. Note that in this embodiment, patches do not necessarily need to be printed in the margin. However, to enable a single printing device to switch between interrupt mode and margin use mode, patches are printed in the margin even in interrupt mode. Therefore, if only interrupt mode is supported, a sensor may be provided inside the guaranteed print area 801 and patches may be printed in the corresponding position.

[0091] In this embodiment, the gradation correction patches are printed side by side outside the printable area, and the patches are read by sensors 861 and 862 on the print surface side. Therefore, the patches of each color are aligned parallel to the transport direction in accordance with the position of the sensor. Note that the sensor may be configured with multiple pairs to accommodate multiple sheet sizes.

[0092] A total of 40 patches are printed on printing paper 800: ten patches for each of the single toner colors cyan 810, magenta 850, yellow 830, and black 840, each with a density of 10% increments. For example, in the cyan color patch group 810, starting with patch 820 at 100% density, patches 820 to 829 are printed with densities decreasing in 10% increments. Patch 829 has a density of 10%. The same ten patches are also printed for magenta, yellow, and black, and feedback information required for gradation correction can only be generated once the reference and measurement data for all four colors are collected. The gradation correction patches are then combined with the image generated by the image generation unit 307 by the patch composition unit 309.

[0093] 8B is a cross-sectional view of the transport path inside the image forming apparatus, seen from the side. Toner is transferred to printing paper 800 by developing units 871-874 for each of the CMYK colors, and then fixed by a fixing unit 875. After that, patches 810, 830, 840, and 850 are read by color sensors 861 and 862, which are installed on both the left and right ends of the transport direction. The color sensors are installed on the printing surface side.

[0094] FIG. 8C shows an example of reference values, measurement values, and correction values ​​generated based on the CMYK density information scanned by color sensors 861, 862. As shown in FIG. 8A, a total of 40 patches, 10 for each CMYK, are printed on printing paper 800, and when these are read by the sensor, 40 measurement values ​​are obtained. In this embodiment, the sensor control unit 312 digitizes and stores the patch densities of the color sensor in 1024 levels. The colorimetric results notified by the sensor control unit 312 are stored in the reference information storage unit 311 as reference values ​​for each paper type set in the paper feed tray. The colorimetric results must be managed for each paper type.

[0095] If the colorimetry results for a certain paper notified by the sensor control unit 312 are for a paper not registered in the reference information storage unit 311, the 40 colorimetry results are stored as new reference values ​​(reference information) 881. The reference values ​​881 include the values ​​for each toner color component and the reference values ​​corresponding to those values. If the colorimetry results for a paper notified by the sensor control unit 312 are for a paper already registered in the reference information storage unit 311, the colorimetry results are treated as new measurement values ​​882, and a correction value 883 is calculated from the difference between the reference value and the measurement value. The correction value 883 is stored in the correction information storage unit 310. Note that, although the correction values ​​are stored in this embodiment, it is also possible to store the measurement values ​​and calculate the correction values ​​each time from the difference between the reference value and the measurement value. The YMCK color values ​​after the reference color conversion are further corrected according to this correction information. For example, if the correction value is +1, the image generation unit 307 corrects the color values ​​so that the measurement value increases by +1. Alternatively, the color correction table used for correction is adjusted. It is possible to determine in advance how adjustments will affect the measured values, and then make corrections accordingly, or adjust the correction table accordingly.

[0096] FIG. 8D(a) is an example of a table used by the reference information storage unit 311 to manage reference values. The record information includes the following fields: paper type 891, target paper feed tray 892, reference value (1 / 2 speed) 893, reference value (1 / 1 speed) 894, generated page ID 895, and timestamp 896. In the management table in (a), plain paper 3 is loaded in paper feed tray 1. During the print process for the 60,014th page since power-on at 10:04:06 on July 18, 2019, plain paper 3 is fed from paper feed tray 1 at 1 / 1 speed. The print results are measured and registered as reference values. If plain paper 3 is removed from paper feed tray 1, the record information is deleted. This is as described in FIG. 5 and other figures.

[0097] FIG. 8D(b) is an example of a table used by the correction information storage unit 310 to manage correction values. The basic structure of this table is the same as the reference value management table, except that the reference value is replaced with the correction value. When the paper is removed from the target paper feed tray 897, the record information is deleted. ●Configuration of information processing terminal Next, a description will be given of the control of an application running on the information processing terminal 102 that submits a print job to the printing apparatus 101 that performs the tone correction described above.

[0098] 10 shows an example of the internal configuration of a general information processing terminal, and illustrates the internal configuration of the information processing terminal 102 in Fig. 1. The information processing terminal 102 includes a CPU 1001, a RAM 1002, an auxiliary storage device 1004, an image display device 1005, an input device 1003, a NIC 1006, and a main bus 1007.

[0099] The CPU 1001 performs information processing when controlling the information processing terminal 102 of the present invention. The RAM 1002 is memory that provides a work area for the CPU 1001. The auxiliary storage device 1004 is a hard disk, floppy disk, CD-ROM, etc. that provides the control program in this embodiment. This auxiliary storage device 1004 stores, for example, various application programs, data, user information, and device information. It is also used for temporary data storage. The image display device 1005 is used to notify the user of messages and is specifically a CRT display, LCD display, etc. The input device 1003 is used to input user commands and is specifically a mouse, keyboard, etc. The network interface card (NIC) 1006 exchanges data with other network devices via the LAN (100). These devices are connected by a main bus 1007.

[0100] Print settings 11 shows an example of a print setting screen of a printer driver that is displayed on the image display device 1005 of the information processing terminal 102 and allows the user to specify print settings. A print setting screen 1100 is made up of tabs 1101 to 1105. It is possible to display any one of the setting screens of a basic setting tab 1101, a page setting tab 1102, a finishing and adjustment tab 1103, a paper feed tab 1104, and a print quality tab 1105.

[0101] 11 shows an example of a setting screen for the finishing / adjustment tab 1103. In the finishing / adjustment tab 1103, a margin width 1111 is configured to input the margin width as a distance (in mm) from the edge of the paper.

[0102] Margin trimming 1112 is an option for setting whether or not to trim the margin area in the end. Either "Yes" 1113 or "No" 1114 can be selected.

[0103] Adjustment item 1121 is a checkbox that allows the user to select the type of adjustment to be performed. Checked adjustment items are performed. "Front and back image position" and "Gradation" can be independently selected as ON / OFF. Adjustments performed using the inline sensor include gradation correction (the above "gradation") for adjusting image quality as described in this embodiment, and front and back registration adjustment (the above "front and back image position adjustment") for adjusting the image formation position, although a description thereof will be omitted in this embodiment.

[0104] The adjustment method 1122 is configured to select either a margin use type 1123 or a chart insertion type 1124 as a method for adjusting the above adjustment items. If it is determined in steps S1208-S1210 of FIG. 12, which will be described later, that adjustment using the margin use type is not possible, the margin use type 1123 of the adjustment method 1122 is displayed in grayout. Then, the selection cannot be made and the setting is controlled to be invalid. This control will be described later.

[0105] Other tabs include a basic settings tab 1101, a page settings tab 1102, a paper feed tab 1104, and a print quality tab 1105. The basic settings tab 1101 consists of a menu that enables basic print settings such as the number of copies, print orientation, magnification, and output method. The page settings tab 1102 consists of a menu that enables setting the page layout and magnification of the output image. The finishing tab 1103 consists of a menu that enables setting single-sided / double-sided printing, binding direction, and paper ejection method. The paper feed tab 1104 consists of a menu that enables selection of which paper feed tray of the printing device 101 to use for paper when outputting. The print quality tab 1105 consists of a menu that enables setting the image quality of the output image such as color mode (color / monochrome) and resolution.

[0106] When the user presses an OK button 1107 on the print setting specification screen 1100 , the information processing terminal 102 generates a print job 900 (described later with reference to FIG. 9) and transmits the print job 900 to the printing apparatus 101 via the LAN 100 .

[0107] Print job configuration FIG. 9 shows an example of a print job generated by the information processing terminal 102 in steps S1212 and S1214 of FIG. 12, which will be described later. The print job name 901 is identification information or an identifier for the print job. The user ID 902 is identification information for identifying the user using the information processing terminal 102. The user ID 902 may be explicitly specified by the user on the print setting specification screen 1100. The margin width 903 is the value specified by the user in the margin width 1111 on the print setting specification screen 1100. This is a numerical value in mm. The margin trimming 904 is the setting specified by the user in the margin trimming 1112 on the print setting specification screen 1100. "Trim margins" or "Do not trim margins" is stored. The adjustment item 905 is the adjustment item specified by the user in the adjustment item 1121 on the print setting specification screen 1100. As set in the adjustment item 1121 in FIG. 11, one of "front and back image position and gradation," "front and back image position only," "gradation only," or "none" is stored. The adjustment method 906 is the adjustment method specified by the user in the adjustment method 1122 on the print setting specification screen 1100. "Margin use type" or "chart insertion type" is stored. The paper setting 907 stores the setting for the paper to be adjusted. If the adjustment method 906 is the margin use type, the content or the item itself may be omitted. If it is the chart insertion type, the paper type specified by the user is stored. The print settings 908 are print settings such as the number of copies to be printed, staple settings, punch settings, paper feed settings, resolution settings, and print color. The print data 909 is print data specified from any drawing software such as a text editor. It is written in a format that can be interpreted and executed by the printing device 101.

[0108] Creating and sending print jobs 12 is a flowchart showing the process of generating and transmitting a print job in the information processing terminal 102. The process in FIG. 12 is realized, for example, by the CPU 1001 of the information processing terminal 102 reading a program stored in the auxiliary storage device 1004 into the RAM 1002 and executing the program.

[0109] In step S1201, the CPU 1001 accepts a print instruction from the user via an application and starts the printer driver. At this time, the CPU 1001 reads the initial values ​​of various settings, such as print settings and image processing settings, stored in the auxiliary storage device 1004 or the like. Then, in response to a user operation, the CPU 1001 displays a user interface screen of the printer driver, such as that described in FIG. 11, on the image display device 1005. Then, the CPU 1001 accepts the user settings while switching to an appropriate screen in response to the user operation.

[0110] In S1202, the CPU 1001 determines whether all pages of the print data have been spooled. If it is determined that the print data has not been spooled, the CPU 1001 returns to S1202 and repeats the process until the print data has been spooled. On the other hand, if it is determined that the print data has been spooled in S1202, the CPU 1001 expands the print data in S1203.

[0111] Then, in S1204, the CPU 1001 determines whether the Finishing / Adjustment tab 1103 is displayed. If it is determined that the Correction tab 1006 is displayed, then in S1205, the CPU 1001 determines whether the chart insertion type has been selected as the adjustment method. If it is determined that the chart insertion type has been selected as a result of the determination in S1205, then in S1206, the CPU 1001 determines whether the job includes specifications for multiple paper types. If it is determined in S1206 that the job includes specifications for multiple types of paper, then in S1208, the CPU 1001 determines whether "Select Adjustment Paper" has been selected. On the other hand, if it is determined in S1206 that the job includes only a single paper type, the CPU 1001 grays out the adjustment paper selection button on the UI in S1207.

[0112] If it is determined in S1208 that "Select Adjustment Paper" has been selected, the example UI shown in FIG. 13 is displayed, and the selection of adjustment paper is accepted in S1209. Note that the title "Paper for Correction" displayed in FIG. 13 refers to the adjustment paper. The paper selection UI 1301 displays a list of paper types included in the job (i.e., specified in the job). The user selects the paper to be used for adjustment from the list, as shown in a highlighted area 1302. If the selected paper type is selected, the process proceeds to S1210. On the other hand, if it is determined in S1204 that the Correction tab 1006 is not displayed, the CPU 1001 proceeds to S1210. Furthermore, if it is determined in S1205 that the chart insertion type has not been selected, or if it is determined in S1208 that the adjustment paper selection has not been selected, the CPU 1001 also proceeds to S1210.

[0113] In S1210, the CPU 1001 determines whether or not the OK button 1107 has been pressed. If it is determined here that the OK button 1107 has not been pressed, the CPU 1001 returns to S1204 and repeats the process.

[0114] On the other hand, if it is determined in S1208 that the OK button 1107 has been pressed, in S1211 the CPU 1001 receives a print command notified from the application via the OS and generates a print job 900 in accordance with the various print settings set by the user up to this point. It is assumed that information such as user information and job name is set in the generated print job 900. Furthermore, information such as margin width, margin trimming, adjustment items, and adjustment methods is also set. Then, in S1212, the CPU 1001 transmits the generated print job 900 to the image forming apparatus 101 via the LAN 100, and this process ends.

[0115] The print job 900 generated in this manner is sent to the print job generation unit 301 of the printing device 101, which generates a print job in the printing device 101. The print job generated by the printing device 101 may be in the same format as the print job 900, or may be in an internal format of the printing device 101.

[0116] According to the embodiment described above, it is possible to select the adjustment paper and print the correction chart on the selected adjustment paper (selected type of sheet), which allows for tone correction suited to the selected type of sheet and enables high-quality image formation.

[0117] Although the adjustment paper is specified by the user, for example, the priority of the adjustment paper may be determined in advance, and the sheet type with the highest priority among the sheet types used in the job may be set as the adjustment paper. In this embodiment, the specified type of sheet is fed and the gradation correction chart is printed on it, with the condition that a predetermined number of sheets have been printed being set as the condition. However, the condition that triggers printing may be changed to something else.

[0118] [Second embodiment] In this embodiment, if the number of printed pages reaches a predetermined number (a predetermined threshold) while a print job is being executed and printing on a specified type of sheet remains in the job being executed, a color chart is printed on the specified type of sheet.

[0119] This embodiment is the same as the first embodiment, except that the procedure of S1504 in FIG. 15 is changed to the procedure shown in FIG. 17. Therefore, only FIG. 17 will be described, and the rest will be omitted. The job control unit 303 first determines whether the last ejected sheet is the final page (S1700). This determination is similar to S1422 and may be performed together with S1422. Next, it determines whether printing on a sheet of the type specified as adjustment paper remains in the print job being executed in FIG. 14 (S1701). If so, processing to print a chart on the specified adjustment paper begins (S1505-1). S1505-1 corresponds to the processing performed in S1505 in FIG. 15. On the other hand, if it is determined that no adjustment paper remains, it determines whether image quality is prioritized (S1702). Image quality priority may be set, for example, as part of the procedure in FIG. 12. If image quality priority is prioritized, processing to print a chart on the current paper, i.e., the currently supplied sheet, begins without switching the paper feed tray (S1505-2). S1505-2 corresponds to the process performed in S1505 in Fig. 15. In this case, an attempt is made to update the correction information corresponding to the currently used sheet type, not the type specified as the adjustment paper type. If image quality is not a priority, the process ends.

[0120] In this way, it is possible to update the correction information corresponding to the type of printing medium designated as the adjustment paper, as well as to update the correction information corresponding to types of printing medium not designated as the adjustment paper, without interfering with the updating of the correction information corresponding to the type of printing medium designated as the adjustment paper.

[0121] [Third embodiment] In this embodiment, if the number of printed pages reaches a predetermined number during execution of a print job but printing has not been performed on the specified type of sheet, printing of the color chart is postponed until printing on the type of sheet specified in the job being executed. As with the second embodiment, the differences from the first embodiment will be described here.

[0122] A flowchart of the processing of the third embodiment is shown in Fig. 18. Fig. 18 shows the procedure executed by the job control unit 303 in response to receiving a notification of page processing completion, for example, in S1421 of Fig. 14. In this embodiment, the counting up of the number of printed sheets performed in S1419 of Fig. 14 is performed by the job control unit 303.

[0123] First, it is determined whether counting up the number of printed sheets is stopped (S1801). Counting is stopped in the following step S1804. If it is stopped, the number of printed sheets is counted (S1802). It is then determined whether the number of printed sheets has reached a threshold (S1803), and if so, counting the number of printed sheets is stopped (S1804). If it is determined in S1801 that counting is not stopped, the process branches to S1805.

[0124] Next, in S1805, it is determined whether the next sheet is a type of sheet designated as adjustment paper. If so, an instruction to execute a chart insertion job is issued to the print job generation unit 301 (S1806), the number of prints is reset (S1807), and counting the number of prints is restarted (S1808). After this, the process continues from S1503 in FIG. 15. Also, if the number of prints has not reached the threshold in S1803, or if the next sheet is not adjustment paper in S1805, the process ends. In this case, if printing of the final page has not been completed, the loop from S1403 continues, and if it has been completed, the job ends.

[0125] By following the above procedure, even if printing of the specified number of pages has been completed, printing of the gradation correction chart is postponed until printing on the specified adjustment paper comes around. This avoids the waiting time (delay) caused by switching sheets, and improves the quality of the image formed on the specified print medium without reducing productivity.

[0126] [Other Examples] The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program.The present invention can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0127] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0128] 1011 paper feed unit, 1012 image forming unit, 1013 inspection unit, 1014 paper ejection unit

Claims

1. an image forming means for forming an image and a gradation correction chart on a sheet; a conveying means for conveying the sheet on which the image is formed by the image forming means and the sheet on which the gradation correction chart is formed; a detecting means for detecting the gradation correction chart formed on the sheet conveyed by the conveying means; a receiving means for receiving a selection of a sheet type to be used for forming the gradation correction chart from a plurality of sheet types; a control means for controlling the image forming means to form the gradation correction chart on a sheet of the type selected when the number of pages printed since the start of a job for forming an image on a sheet reaches a predetermined number, The control means when the number of pages printed since the job was started reaches the predetermined number and there are no pages to be printed on the type of sheet for which the selection has been accepted among the remaining pages of the job to be printed until the job is completed, determine whether an image quality priority setting is set, and if the image quality priority setting is not set, control the image forming means not to form the gradation correction chart on the type of sheet for which the selection has been accepted, and if the image quality priority setting is set, control the image forming means to form the gradation correction chart on the type of sheet being supplied, When the number of pages printed since the job was started reaches the predetermined number, and when there is a page to be printed on a sheet of the type for which the selection has been accepted among the remaining pages of the job to be printed until the job is completed, control is performed so that the gradation correction chart is formed by the image forming means on a sheet of the type for which the selection has been accepted. An image forming apparatus characterized by:

2. The image correction method further includes a storage unit for storing correction information generated based on the image information of the gradation correction chart detected by the detection unit.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

3. 3. The image forming apparatus according to claim 2, wherein the storage unit generates, for each type of sheet, correction information based on a difference between pre-stored reference information and the image information detected by the detection unit.

4. 4. The image forming apparatus according to claim 3, wherein said storage means stores the image information detected by said detection means as reference information when said reference information is not present.

5. a sheet feed cassette having a plurality of sheet feed stages for accommodating sheets to be fed to the image forming means; a setting means for setting the type of sheets to be accommodated in the paper feed tray; 5. The image forming apparatus according to claim 1, further comprising:

6. 6. The image forming apparatus according to claim 1, wherein the plurality of types of sheets include plain paper and coated paper.

7. The image forming device described in Claim 1, characterized in that when the number of pages printed since the job was started reaches the specified number, and there are no pages printed on the type of sheet for which the selection was accepted among the remaining pages of the job to be printed before the job is completed, and the image quality priority setting is not set, the control means controls to execute a mode in which the gradation correction chart is formed in the margin of the type of sheet being supplied.

8. A program for causing a computer to operate as the control unit of the image forming apparatus according to claim 1 .

9. an image forming step of forming an image and a gradation correction chart on a sheet; a conveying step of conveying the sheet on which the image has been formed in the image forming step and the sheet on which the gradation correction chart has been formed; a detecting step of detecting the gradation correction chart formed on the sheet conveyed in the conveying step; a receiving step of receiving a selection of a sheet type to be used for forming the gradation correction chart from a plurality of sheet types; a control step of controlling the image forming step to form the gradation correction chart on the sheet of the type selected when the number of pages printed since the start of a job to form an image on the sheet reaches a predetermined number, The control step includes: when the number of pages printed since the job was started reaches the predetermined number and there are no pages to be printed on a sheet of the type for which the selection was accepted among the remaining pages of the job to be printed until the job is completed, determine whether an image quality priority setting is set, and if the image quality priority setting is not set, control is performed so that the gradation correction chart is not formed on a sheet of the type for which the selection was accepted by the image forming process, and if the image quality priority setting is set, control is performed so that the gradation correction chart is formed on a sheet of the type being supplied by the image forming process; When the number of pages printed since the job was started reaches the predetermined number, and when there is a page to be printed on a sheet of the type for which the selection has been accepted among the remaining pages of the job to be printed until the job is completed, control is performed so that the gradation correction chart is formed on a sheet of the type for which the selection has been accepted by the image forming process.

2. A method for controlling an image forming apparatus comprising:

Images