Image forming apparatus and display method of image forming apparatus

Abstract

It is necessary to select an appropriate correction control from a plurality of correction controls such as the gradation correction, the maximum density correction, and the secondary transfer voltage correction in accordance with the variation for each print job. However, in the related art, it is not possible to confirm the variation in the printing process other than on the recording medium. For this reason, the user cannot grasp in which print step of the print job the variation has occurred, and may execute erroneous correction control and cause color variation.SOLUTION: The display unit displays first color variation information based on the first color of at least the first print job and the second print job and second color variation information based on the second color of at least the first print job and the second print job.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to displaying color variations in printed matter printed by an image forming apparatus. [Background technology]

[0002] In recent years, on-demand image forming devices (hereafter referred to as "printers") have shown improvements in image quality and productivity, and require less training time for operators, so they are increasingly being introduced as a replacement for offset printing machines. However, the image quality level of offset printing is high, and printers are only used in a limited way. To further expand the printer market, image quality equal to or better than that of offset printing is required. Of particular importance is improved color stability.

[0003] One color stabilization technology for printers is tone correction control, which corrects the gradation of primary colors. A sensor reads the printed material (recording medium on which a toner image is recorded), compares the read color with a target color, determines a correction amount to bring it closer to the target color, and corrects the input image data based on the correction amount, thereby stabilizing the color during the print job. Furthermore, a technology has been disclosed that displays the correction amount during printing to the user for multiple print jobs, allowing the user to understand how the tone correction control is working in response to any fluctuations that occur. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-112771 Summary of the Invention [Problem to be solved by the invention]

[0005] Depending on the variations in each print job, it is necessary to select an appropriate correction control from multiple correction controls, such as gradation correction, maximum density correction, and secondary transfer voltage correction. However, in the past, it was not possible to check variations in the printing process other than on the recording medium. As a result, users were unable to determine which print job's printing process the variations were occurring in, and there was a risk that they would perform the wrong correction control, resulting in color variations. [Means for solving the problem]

[0006] The present invention comprises a printing means for printing on a recording medium according to an input print job, a first acquisition means for acquiring a first color on an image carrier during printing processing, a second acquisition means for acquiring a second color on the printed recording medium, and a display means for displaying color variation information based on the acquired colors, wherein the first acquisition means acquires the first color of at least a first print job and a second print job, the second acquisition means acquires the second color of at least the first print job and the second print job, and the display means displays first color variation information based on the first color of at least the first print job and the second print job, and second color variation information based on the second color of at least the first print job and the second print job. [Effects of the Invention]

[0007] According to the present invention, it is possible to know in which printing process of which print job a fluctuation occurs. [Brief explanation of the drawings]

[0008] [Figure 1] A diagram showing an example of a network configuration including a printing system. [Figure 2] 1 is a cross-sectional view showing an example of the hardware configuration of an image forming apparatus; [Figure 3] Block diagram showing the internal configuration of the image forming device, external controller, and client PC [Figure 4] Schematic diagram showing how colors are acquired on an intermediate transfer belt, which is an image carrier. [Figure 5] Schematic diagram showing how to acquire color on a recording medium [Figure 6] FIG. 10 is a flowchart showing a processing procedure in the image adjustment unit in the first embodiment. [Figure 7] Schematic diagram of the screen for accepting settings for color variation detection [Figure 8] Schematic diagram showing color variations across multiple printing processes [Figure 9] Schematic diagram of a screen that shows the user the result of the judgment on the necessity of adjustment based on the variation in color tone. [Figure 10] FIG. 10 is a schematic diagram showing an example of changing the toner density conditions displayed on a screen showing color variations; [Figure 11] FIG. 10 is a schematic diagram showing an example of accepting an instruction from a user to refer to past data on a screen showing color variations; [Figure 12] A schematic diagram showing how colors are acquired on an intermediate transfer belt, which is an image carrier, when multiple patches for acquiring colors are arranged. [Figure 13] A schematic diagram showing how to acquire color on a recording medium when multiple color acquisition patches are arranged. [Figure 14] FIG. 10 is a flowchart showing a processing procedure in the image adjustment unit in the second embodiment. [Figure 15] Schematic diagram of the screen that accepts the specification of the color acquisition position from the input image data [Figure 16] FIG. 10 is a schematic diagram illustrating how a color tone is acquired on an intermediate transfer belt, which is an image carrier, in Example 2. [Figure 17] Schematic diagram showing how to acquire color on a recording medium in Example 2. [Figure 18] FIG. 10 is a schematic diagram illustrating estimation of an engine state in the second embodiment. [Figure 19] Schematic diagram showing an example of displaying the acquired color difference [Figure 20] Schematic diagram of the screen for checking long-term fluctuations DETAILED DESCRIPTION OF THE INVENTION

[0009] Each embodiment of the present invention will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention as claimed, and not all of the combinations of features described in each embodiment are necessarily essential to the solution of the present invention. In this embodiment, an image forming apparatus will be used as an example of an information processing apparatus, but the present invention is not limited to this.

[0010] Example 1 In this embodiment, in addition to an input image toner image based on an input image on an intermediate transfer belt 308, which is an image carrier of the printing unit 107 (described later), a patch toner image whose color can be measured is formed on the edge of the recording medium, and the color on the image carrier is acquired by a density sensor 310. Furthermore, an image based on the input image toner image and the patch toner image is formed on the recording medium, and the color of the patch on the recording medium is acquired by an image reading unit 311.

[0011] In this embodiment, the toner amount is used as an example of color tint. Note that color tint is not limited to the above example. Any scale capable of expressing the color difference of an image can be used, and lightness, saturation, or hue may also be used. The variation is calculated from two colors acquired in different printing processes, and color variation information indicating the color difference (lightness difference, saturation difference, hue difference) is displayed during the print job. By displaying the variation, the user is notified in real time whether there is a printing process that is causing the variation.

[0012] In this embodiment, an example of calculating the variation in toner amount will be described, but it is desirable that the variation be calculated in an optimal format depending on the color to be acquired. For example, if the above-mentioned lightness, saturation, and hue are acquired as the color, the color difference, which is used as a measure of color difference in the field of color science, can be used as the variation. A detailed implementation method will be described below.

[0013] <System configuration> Fig. 1 is a diagram showing an example of a network configuration including a printing system (image processing system) according to this embodiment. As shown in Fig. 1, the printing system 100 includes an image forming apparatus 101 and an external controller 102. The image forming apparatus 101 and the external controller 102 are communicably connected via an internal LAN 105 and a video cable 106. The external controller 102 is communicably connected to a client PC 103 via an external LAN 104.

[0014] The client PC 103 can issue a print instruction to the external controller 102 via the external LAN 104. A printer driver is installed in the client PC 103, which has a function of converting image data to be printed into a page description language (PDL) that can be processed by the external controller 102. A user who wishes to print can issue a print instruction via the printer driver from various applications installed in the client PC 103 by operating the client PC 103.

[0015] The printer driver transmits PDL data, which is print data, to the external controller 102 based on a print instruction from the user. When the external controller 102 receives the PDL data from the client PC 103, it analyzes and interprets the received PDL data. Based on the results of the interpretation, it performs rasterization processing to generate a bitmap image (print image data) with a resolution matching the image forming apparatus 101, and issues a print instruction by submitting a print job to the image forming apparatus 101.

[0016] Next, the image forming apparatus 101 will be described. The image forming apparatus 101 is connected to a plurality of devices with different functions and is configured to be capable of complex printing processes such as bookbinding. The image forming apparatus 101 has a printing unit 107 (image forming unit), an image inspection unit 109, a stacker 110, and a finisher 111. Each module will be described below.

[0017] The printing unit 107 generates an image including a patch on the edge of the recording medium in accordance with the print job, and ejects the printed recording medium with the image printed on it. The printed recording medium ejected from the printing unit 107 is transported inside each device in the order of the image inspection unit 109, stacker 110, and finisher 111. The printing unit 107 also includes a density sensor 310 that acquires the color tone on the image carrier, which is the transport path during the process of printing the image on the recording medium, and acquires the color tone on the image carrier.

[0018] In this embodiment, the image forming apparatus 101 of the printing system 100 is an example of an image forming apparatus, but the printing unit 107 included in the image forming apparatus 101 may also be referred to as the image forming apparatus. The printing unit 107 forms (prints) an image using toner (color material) on a recording medium fed and transported from a paper feed unit disposed below the printing unit 107.

[0019] Furthermore, when the printing unit 107 receives an instruction for the correction means from a user operation or an image inspection unit 109 (described later), it prints a test chart corresponding to the correction means from a group of test charts stored in advance. Furthermore, the image reading unit 331 reads the printed matter and acquires image data. Based on the acquired results, the image inspection unit 109 then performs main scanning unevenness correction to adjust the uniformity of the image density, automatic gradation correction to maintain maximum density and monochromatic gradation, adjustment of the secondary transfer voltage, automatic color correction to adjust for variations in multi-colors, and the like.

[0020] The inserter 108 is a device for inserting an insertion sheet, and can insert an insertion sheet at any position in the group of sheets printed by the printing unit 107 and transported.

[0021] The image inspection unit 109 acquires the color on the recording medium using the image reading unit 331 based on the printed recording medium that has been printed by the printing unit 107 and transported through a transport path. The image inspection unit 109 acquires the acquired color variation on the recording medium and the color variation on the image carrier acquired by a density sensor 310 provided in the printing unit 107, and displays the color variation on the display unit 215, which will be described later. Furthermore, the image inspection unit 109 displays the two color variations on the recording medium and the image carrier, as well as a comparison result that is the difference between the two color variations, and determines whether image adjustment by the printing unit 107 is necessary. Details of the method for acquiring the color variation and the determination process for determining the need for image adjustment will be described later.

[0022] The stacker 110 is a device capable of stacking a large number of printed recording media. The finisher 111 is a device capable of performing finishing processes such as stapling, punching, and saddle stitching on the conveyed printed recording media. The recording media processed by the finisher 111 are discharged to a predetermined discharge tray.

[0023] 1, an external controller 102 is connected to the image forming apparatus 101, but this embodiment can also be applied to a different configuration. For example, a configuration may be used in which the image forming apparatus 101 is connected to an external LAN 104, and print data is sent from a client PC 103 to the image forming apparatus 101 without going through the external controller 102. In this case, data analysis and rasterization of the print data are performed by the image forming apparatus 101.

[0024] <Hardware Configuration of Image Forming Apparatus 101> 2 is a cross-sectional view showing an example of the hardware configuration of the image forming apparatus 101. A specific example of the operation of the image forming apparatus 101 will be described below with reference to FIG.

[0025] The printing unit 107 includes multiple paper feed decks. In this embodiment, two types of decks, paper feed decks 311 and 312, are included. Each paper feed deck stores various types of recording media (paper). Of the recording media stored in each paper feed deck, the topmost recording medium is separated one by one and fed to a conveyance path 303. Each of the image forming stations 304 to 307 includes a photosensitive drum (photoconductor) and forms a toner image on the photosensitive drum using toner of a different color. Specifically, the image forming stations 304 to 307 form a toner image using toner of yellow (Y), magenta (M), cyan (C), and black (K), respectively.

[0026] The toner images of each color formed in the image forming stations 304 to 307 are transferred onto the intermediate transfer belt 308 in order, superimposed on top of each other (primary transfer). The toner images transferred onto the intermediate transfer belt 308 are transported to a secondary transfer position 309 as the intermediate transfer belt 308 rotates. In this embodiment, in addition to the toner images based on input image data, patches for acquiring color are formed on the intermediate transfer belt 308. A density sensor 310 acquires the color on the intermediate transfer belt 308 by measuring the formed patches.

[0027] The density sensor 310 is composed of a light-emitting element and a light-receiving element, and measures the light reflected by the light-receiving element after the light emitted from the light-emitting element is reflected by the surface of the intermediate transfer body 308, which is an image carrier. The density sensor 310 obtains a brightness value from the ratio of the light emitted from the light-emitting element to the reflected light. The density sensor 310 calculates the toner amount based on a pre-stored conversion table that converts brightness values ​​into toner application amounts. The process of calculating the toner amount from brightness values ​​will be described later.

[0028] At the secondary transfer position 309, a toner image is transferred from the intermediate transfer belt 308 onto the recording medium conveyed along the conveying path 303 (secondary transfer). After the secondary transfer, the recording medium is conveyed to a fixing unit 311. The fixing unit 311 includes a pressure roller and a heating roller. As the recording medium passes between these rollers, heat and pressure are applied to the recording medium, thereby performing a fixing process that fixes the toner image onto the recording medium. After passing through the fixing unit 311, the recording medium is conveyed along a conveying path 312 to a connection point 315 between the printing unit 107 and the image inspection unit 109. In this way, a color image is formed (printed) on the recording medium.

[0029] If further fixing processing is required depending on the type of recording medium, the recording medium that has passed through fixing unit 311 is led to conveyance path 314 provided with fixing unit 313. Fixing unit 313 performs further fixing processing on the recording medium conveyed on conveyance path 314. The recording medium that has passed through fixing unit 313 is conveyed to connection point 315. Furthermore, if an operating mode for double-sided printing is set, an image is printed on the first side, and the recording medium that has been conveyed on conveyance path 312 or conveyance path 314 is led to reversal path 316.

[0030] The recording medium inverted by the reversing path 316 is guided to the double-sided conveying path 317 and conveyed to the secondary transfer position 309. As a result, a toner image is transferred to the second side of the recording medium, opposite to the first side, at the secondary transfer position 309. The recording medium then passes through the fixing unit 311 (and fixing unit 313), completing the formation of a color image on the second side of the recording medium. After the image formation (printing) in the printing unit 107 is completed, the printed recording medium is conveyed to the connection point 315 and conveyed into the image inspection unit 109.

[0031] The image inspection unit 109 includes an image reading unit 331 having a CIS (Contact Image Sensor) on a transport path 330 along which the printed recording medium from the printing unit 107 is transported. The image reading unit 331 is disposed so as to read the top surface (first surface) of the recording medium. Note that the image reading unit 331 may be configured with a CCD (Charge Coupled Device) or a line scan camera instead of the CIS, for example.

[0032] The image reading unit 331 acquires the signal values ​​of the RGB three-channel color image as color tints. The toner amount is calculated based on a pre-prepared conversion table that converts RGB values ​​into toner application amounts. The process of calculating the toner amount from RGB values ​​will be described in detail later. The image inspection unit 109 calculates the variation from two colors in different printing processes and displays the result on the display unit 215 to notify the user of real-time color variation during the print job. Furthermore, the image inspection unit 109 determines the need for correction measures in the printing unit 107 based on the variation in each printing process and the difference between processes. The recording media that have passed the image inspection unit 109 are transported in order to the stacker 110. The specific processing of the image inspection unit 109 will be described later.

[0033] The stacker 110 includes a stack tray 341 as a tray on which printed recording media transported from the image inspection unit 109, which is disposed upstream in the transport direction of the printed recording media, are stacked. The printed recording media that have passed the image inspection unit 109 are transported along a transport path 344 within the stacker 110. The printed recording media transported along the transport path 344 are guided to a transport path 345, whereby the printed recording media are stacked on the stack tray 341. The stacker 110 further includes an escape tray 346 as a paper discharge tray.

[0034] In this embodiment, the escape tray 346 is used to discharge printed matter that has been determined to have a color variation by the image inspection unit 109. A printed matter that has been detected to have a color variation and is transported along the transport path 344 is guided to the transport path 347 and transported to the escape tray 346. Printed recording media that are transported in the stacker 110 without being stacked or discharged are transported via the transport path 348 to the subsequent finisher 111.

[0035] The stacker 110 further includes an inverting unit 349 for inverting the orientation of the printed recording medium being transported. The inverting unit 349 is used, for example, to make the orientation of the recording medium input into the stacker 110 the same as the orientation of the printed recording medium when it is stacked on the stack tray 341 and output from the stacker 110. Note that the inverting operation by the inverting unit 349 is not performed on printed recording media that are not stacked in the stacker 110 and are transported to the finisher 111.

[0036] The finisher 111 executes a finishing function designated by a user on a printed recording medium conveyed from a diagnostic unit 108 disposed upstream in the conveyance direction of the printed recording medium. In this embodiment, the finisher 111 has finishing functions such as a staple function (one-point or two-point binding), a punch function (two-hole or three-hole), and a saddle stitch binding function. The finisher 111 has two paper output trays 351 and 352.

[0037] When finishing processing is not performed by the finisher 111, the printed recording medium transported to the finisher 111 is discharged to a paper output tray 351 via a transport path 353. When finishing processing such as stapling is performed by the finisher 111, the printed recording medium transported to the finisher 111 is led to a transport path 354. The finisher 111 uses a finishing processing unit 355 to perform finishing processing specified by the user on the printed recording medium transported on the transport path 354. The finisher 111 then discharges the printed recording medium, which has been subjected to finishing processing, to a paper output tray 352.

[0038] <Functional configuration diagram> FIG. 3 is a schematic functional block diagram of the image forming apparatus 101, the external controller 102, and the client PC 103. As shown in FIG.

[0039] The printing unit 107 of the image forming apparatus 101 includes a communication I / F (interface) 201, a network I / F 204, a video I / F 205, a CPU 206, a memory 207, an HDD unit 208, and a UI display unit 202. The printing unit 107 further includes a print unit 203 and a density sensor 310. These are connected to the printing unit 107 via a system bus 209 so as to be able to send and receive data to and from each other. The communication I / F 201 is connected to the image inspection unit 109, stacker 110, and finisher 111 via a communication cable 260.

[0040] The CPU 206 communicates to control each device via the communication I / F 201. The network I / F 204 is connected to the external controller 102 via the internal LAN 105 and is used for communicating control data and the like. The video I / F 205 is connected to the external controller 102 via the video cable 106 and is used for communicating data such as image data.

[0041] Note that the printing unit 107 (image forming apparatus 101) and the external controller 102 may be connected only by a video cable 106, as long as the external controller 102 can control the operation of the image forming apparatus 101. Various programs and data are stored in the HDD unit 208. The CPU 206 controls the overall operation of the printing unit 107 by executing the programs stored in the HDD unit 208. The memory 207 stores programs and data required when the CPU 206 performs various processes. The memory 207 operates as a work area for the CPU 206.

[0042] The UI display unit 202 receives various setting inputs and operation instructions from the user, and is used to display various information such as setting information and the processing status of a print job, etc. In this embodiment, the UI display unit 202 is used to switch the setting of whether or not to perform color variation detection during printing.

[0043] Furthermore, under the control of the CPU 206, the printing unit 107 measures the color on the intermediate transfer belt 308 in the print unit 203 with a density sensor 310 and stores the measured luminance value in the memory 207. Schematic diagrams showing the relationship between the toner image on the intermediate transfer belt 308 and the density sensor 310 when the printing unit 107 acquires the luminance value are shown in Figures 4(a) and (b).

[0044] FIG. 4(a) is a bird's-eye view of the intermediate transfer belt 308 from a position facing the belt, and FIG. 4(b) is a cross-sectional view from a position parallel to the intermediate transfer belt 308. In the example of FIG. 4, in addition to a toner image 502 corresponding to the input image, patches 501 for measuring color are arranged at the rear end of the recording medium. The number of patches 501 is the same as the number of toner colors. In this embodiment, since the printing unit 107 is equipped with four colors of toner (CMYK), four different patches are arranged. Each patch is a single-color patch with an area ratio of 50%. The density sensor 310 irradiates the patch 501 with light and measures the reflected light to obtain a luminance value, which represents the color on the image carrier. The area ratio refers to the amount of toner applied per unit area and is an index of toner concentration. Detailed processing will be described later. The stored luminance value is referenced by the image inspection unit 109, which will be described later. Detailed processing will be described later.

[0045] The image inspection unit 109 includes a communication I / F 211, a CPU 212, a memory 213, an HDD unit 214, an image reading unit 331, a determination processing unit 216, and a UI display unit 215. These devices are connected via a system bus 209 so that they can send and receive data to and from each other. The communication I / F 211 is connected to the printing unit 107 via a communication cable 260. The CPU 212 performs communication necessary for controlling the image inspection unit 109 via the communication I / F 211. The CPU 212 controls the operation of the image inspection unit 109 by loading a control program stored in the HDD unit 214 into the memory 213 and executing it. The HDD unit 214 stores a control program for the image reading unit 331 and a processing program executed by the determination processing unit 216 to determine the necessity of a correction method in the printing unit 107. The image reading unit 331 acquires RGB values, which represent the color of the conveyed printed matter, in accordance with instructions from the CPU 212. 5(a) and 5(b) are schematic diagrams showing the relationship between the toner image on the recording medium and the image reading unit 331 when acquiring RGB values.

[0046] FIG. 5 shows an example in which the toner image on the intermediate transfer belt 308 shown in FIG. 4 is transferred and fixed onto the recording medium 503 and conveyed to the conveying path 330. Similar to FIG. 4, FIG. 5(a) is a bird's-eye view from a position facing the conveying path 330, and FIG. 5(b) is a cross-sectional view from a position parallel to the conveying path 330. In FIG. 5, the image reading unit 331 reads patches 501 formed on the recording medium 503. The image reading unit 331 acquires RGB signal values ​​representing the color of each patch. The CPU 212 converts the RGB values ​​and the luminance values ​​acquired by the density sensor 310 into toner amounts, and calculates the presence or absence of fluctuations from the difference from the target toner amount. Furthermore, the CPU 212 determines the need for correction measures in the printing unit 107 based on the presence or absence of the two fluctuations and the difference in fluctuations between the printing processes.

[0047] The UI display unit 215 displays the color variation on the image carrier and the color variation on the recording medium 503. Furthermore, the UI display unit 215 is used to display the difference between the two variations, the determination result of the need for a correction means based on the variation and the difference, and adjustment instructions. The UI display unit 215 also serves as a user operation instruction unit for the image inspection unit 109, and is operated by the user to accept various instructions. The UI display unit 215 accepts, for example, instructions for image adjustment means and instructions to change the display content.

[0048] The stacker 110 controls whether the printed recording medium transported along the transport path is discharged to a stack tray, discharged to an escape tray, or transported to a finisher 111 connected downstream in the transport direction of the printed recording medium.

[0049] The finisher 111 controls the transport and discharge of printed recording media, and performs finishing processes such as stapling, punching, or saddle stitching.

[0050] The external controller 102 includes a CPU 251, a memory 252, an HDD unit 253, a keyboard 256, a display unit 254, network I / Fs 255 and 257, and a video I / F 258. These devices are connected via a system bus 259 so as to be able to send and receive data to and from each other.

[0051] The CPU 251 executes programs stored in the HDD unit 253 to control the overall operation of the external controller 102, such as receiving print data from the client PC 103, RIP processing, and transmitting print data to the image forming apparatus 101. The memory 252 stores programs and data required for the CPU 251 to perform various processes. The memory 252 operates as a work area for the CPU 251.

[0052] Various programs and data are stored in the HDD unit 253. The keyboard 256 is used for inputting operation instructions from the user to the external controller 102. The display unit 254 is, for example, a display, and is used for displaying information about applications currently being executed in the external controller 102 and an operation screen.

[0053] The network I / F 255 is connected to the client PC 103 via the external LAN 104 and is used for communicating data such as print instructions. The network I / F 257 is connected to the image forming apparatus 101 via the internal LAN 105 and is used for communicating data such as print instructions. The external controller 102 is configured to be able to communicate with the printing unit 107, the diagnostic unit 108, the stacker 110, and the finisher 111 via the internal LAN 105 and a communication cable 260. The video I / F 258 is connected to the image forming apparatus 101 via the video cable 106 and is used for communicating data such as image data (print data).

[0054] The client PC 103 includes a CPU 261, a memory 262, an HDD unit 263, a display unit 264, a keyboard 265, and a network I / F 266. These devices are connected to each other via a system bus 269 so that they can send and receive data. The CPU 261 controls the operation of each device via the system bus 269 by executing a program stored in the HDD unit 263.

[0055] This allows various processes to be performed by the client PC 103. For example, the CPU 261 generates print data and issues print instructions by executing a document processing program stored in the HDD unit 263. The memory 262 stores programs and data required for the CPU 261 to perform various processes. The memory 262 operates as a work area for the CPU 261.

[0056] The HDD unit 263 stores various applications such as a word processing program, programs such as a printer driver, and various data. The display unit 264 is, for example, a display, and is used to display information about applications running on the client PC 103 and an operation screen. The keyboard 265 is used to input operation instructions for the client PC 103 from the user. The network I / F 266 is communicably connected to the external controller 102 via the external LAN 104. The CPU 261 communicates with the external controller 102 via the network I / F 266.

[0057] <Processing flow of the determination processing unit 216> The determination process in the image inspection unit 109 according to this embodiment will be described with reference to FIG. 6. FIG. 6 is a flowchart showing the processing procedure for calculating color variations during a print job executed by the printing unit 107 in the image inspection unit 109 and displaying the results. Note that FIG. 6 shows the overall flow from setting to execute color variation detection to the end of the print job. The symbol "S" in the explanation of the flowchart represents a step. This also applies to the explanation of the following flowcharts. The processing of each step in FIG. 6 is executed by the CPU 206 of the printing unit 107 and the CPU 212 of the image inspection unit 109.

[0058] First, in S601, the CPU 206 accepts a request to perform color variation detection based on a user instruction on the UI display unit 202. FIG. 7 shows a schematic diagram of a screen for accepting instructions from the user. FIG. 7(a) shows the initial screen before accepting instructions from the user. Until a check instruction is received in a check box 701a, the input section for the variation standard for each color material is grayed out and input is not possible. When the check box 701a is checked, the input section for the variation standard for each color material is ungrayed out and an instruction for a variation standard value from the user is accepted. The variation standard value is input by the user using a numeric keypad or the like (not shown).

[0059] When a print job is executed after receiving an instruction from the user to perform color variation detection, the process proceeds to S602 and subsequent steps. The processes of S603 to S612 are performed on a page-by-page basis. If the print job is data consisting of multiple pages, S603 to S612 are repeated for each page until printing of all pages included in the print job is completed.

[0060] In S602, the CPU 212 acquires fluctuation data of past print jobs stored in the HDD unit 214. The acquired fluctuation data is expanded in the memory unit 213, and further controls the UI display unit 215 to display the fluctuation data.

[0061] 8(a) shows a schematic diagram of the screen. Details of the screen will be explained in S610 below. Once the past fluctuation data is displayed on the UI display unit 215, the process proceeds to S603.

[0062] In S603, the CPU 206 controls the print unit 203 to form a toner image corresponding to the input image data and the color acquisition patch 502 on the photosensitive member, and transfer the toner image to the intermediate transfer belt 308. When the toner image transferred to the intermediate transfer belt 308 is transported to the position of the density sensor 310 as the intermediate transfer belt 308 rotates, the process proceeds to S604.

[0063] In S604, the CPU 206 controls the density sensor 310 to acquire the luminance value of the color acquisition patch 502. The acquired luminance value is stored in the memory 207. When acquisition of the luminance value is completed, the process proceeds to S605.

[0064] In S605, the CPU 206 controls the print unit 203 to transport the toner images (501, 502) and form (print) a color image on the recording medium. Once the image is formed on the recording medium and transported to a position where the color can be read by the image reading unit 311, the process proceeds to S606. Steps from S606 onwards are performed by the image inspection unit 109.

[0065] In S606, the CPU 212 controls the image reading unit 311 to acquire the RGB values ​​of the color acquisition patch 502. The acquired RGB values ​​are stored in the memory 213. When the CPU 212 completes acquisition of the RGB values ​​acquired on the recording medium by the image reading unit 311, the process proceeds to S607.

[0066] In S607, the CPU 214 acquires the luminance value of the density sensor 310 acquired on the intermediate transfer belt 308, which is stored in the memory 207 of the printing unit 107, and converts it into a toner amount. Next, the CPU 214 calculates the variation between the converted toner amount and a target toner amount (target toner amount T50%), which will be described later. Furthermore, the CPU 214 compares the calculated variation in the toner amount with a variation reference value Tth, and determines whether the variation in the toner amount on the intermediate transfer belt 308 exceeds the reference value.

[0067] First, the conversion from luminance values ​​to toner amounts by the CPU 214 will be described. The CPU 214 converts from luminance values ​​to toner amounts using a known one-dimensional LUT. In this embodiment, a one-dimensional LUT indicating the relationship between luminance values ​​and toner amounts is stored in advance in the HDD unit 214 for each toner color, and the CPU 214 references it to perform the conversion process.

[0068] An example of a one-dimensional LUT is shown in Table 1. Table 1 shows an example of K toner with 8-bit input and output. A one-dimensional LUT holds output values ​​for input values ​​at equal intervals. When an intermediate value not held by the LUT is given, the output value is calculated based on known interpolation calculation processing. A test patch in which a patch with a varying amount of toner is recorded on an image carrier is measured with a weight scale. Based on the measurement results, a toner concentration of 0.50 [mg / cm 2 ] is normalized to 8 bits so that it becomes 255, and is stored in the HDD unit 214.

[0069] [Table 1]

[0070] Next, an example of calculating the variation between the converted toner amount and the target toner amount (target toner amount T50%) will be described. ITB and the target toner amount T50%. Finally, the calculated toner amount fluctuation is compared with the fluctuation reference value Tth to determine whether or not there is a fluctuation. If the absolute value of the fluctuation exceeds the fluctuation reference value Tth, it is determined that there is a fluctuation that exceeds the reference.

[0071] Below, the following judgment formula (1) is applied to the toner amount TITB calculated from the brightness value, the target toner amount T50%, and the fluctuation reference value Tth to determine whether or not there is a fluctuation on the image carrier that exceeds the reference. The judgment result RITB on the image carrier is one of three values: 1 if the density is higher than the target, -1 if the density is lower, or 0 if the fluctuation is below the reference. RITB is performed for each toner color, but since the judgment is similar, explanation will be omitted.

[0072] [Judgment formula 1] T 50% -T ITB <0 and T th < |T 50% -T ITB | Then R ITB =1 T 50% -T ITB >0 and Tth < |T 50% -T ITB | Then R ITB =-1 Other than the above, R ITB =0

[0073] Judgment result R ITB Once the calculation is completed and stored in the memory 213, the process proceeds to S608. Next, S608, in which color variation information on the recording medium 304 (the difference between the target value and the acquired toner amount for each page) is calculated, will be described. In S608, the RGB values ​​stored in the memory 213 are acquired by the CPU 212 and converted into toner amounts. Next, the converted toner amounts are compared with the target toner amount (target toner amount T 50%) The fluctuation of the calculated toner amount is calculated based on the fluctuation reference value T th It is compared with the reference value to determine whether the fluctuation in the amount of toner on the recording medium 304 exceeds the reference value.

[0074] First, the conversion from RGB values ​​to toner amounts will be described. The conversion from RGB values ​​to toner amounts is performed using a known 3D LUT designed based on the relationship between the RGB values ​​acquired by the image reading unit 311 and the toner amounts. In this embodiment, a 3D LUT indicating the relationship between the RGB values ​​and the toner amounts is stored in advance in the HDD unit 214 for each toner, and the CPU 214 references it to perform the conversion process. An example of a 3D LUT is shown in Table 2.

[0075] Table 2 shows an example of 8-bit K toner for both input and output. The 3D LUT holds output values ​​for input values ​​at equal intervals. When an intermediate value not held by the LUT is given, the output value is calculated based on known interpolation calculation processing. The LUT uses a gravimeter to measure the toner amount, which is the weight of an unfixed toner image recorded on a standard recording medium 304 assumed by the printing unit 107, with patches with a varying amount of toner in advance. Similar to the color variation information on the image carrier 308, based on the measurement results, a value of 0.50 [mg / cm 2] is normalized to 8 bits so that it becomes 255, and is stored in the HDD unit 214. The relationship stored in the 3D LUT varies depending on the basis weight and surface properties of the paper used as the recording medium 304, so it is more preferable to be able to calibrate it based on the recording medium 304 used by the user, as shown in Japanese Patent Application Laid-Open No. 2007-272112.

[0076] In this embodiment, the toner amount is calculated using all RGB values, but the present invention is not limited to this example. Any method for calculating the toner amount from RGB values ​​may be used, and for example, a method for calculating the toner amount from a signal value that is complementary to the toner color may be used.

[0077] [Table 2]

[0078] Next, the converted toner amount and the target toner amount (target toner amount T 50% The variation is calculated by using the toner amount T paper and the target toner amount T 50% Finally, the calculated toner amount fluctuation and the fluctuation reference value T th The absolute value of the fluctuation is compared with the fluctuation reference value T th If the toner amount T calculated from the RGB values ​​exceeds the reference value, it is determined that there is a fluctuation that exceeds the reference value. paper and the target toner amount T 50% , fluctuation reference value T th The following judgment formula (2) is applied to the recording medium 304 to determine whether there is a fluctuation exceeding the reference value. The judgment result R on the recording medium is one of three values: 1 if the density is increased relative to the target, -1 if the density is decreased, and 0 if the fluctuation is below the reference value. paper Let R paper is performed for each toner color, but the same determination is performed and therefore the explanation will be omitted.

[0079] [Judgment formula 2] T 50% -Tpaepr <0 and T th < |T 50% -T paepr | Then R paper =1 T 50% -T paepr >0 and T th < |T 50% -T paepr | Then R paper =-1 Other than the above, R paper =0

[0080] Judgment result R paper Once the calculation is completed and stored in the memory 213, the process proceeds to S609. Next, S609 will be described, in which the difference in the toner amount between the printing processes is calculated and it is determined whether there is a fluctuation exceeding the standard between the printing processes.

[0081] In S609, the CPU 214 calculates T ITB and T paper In this embodiment, the difference is calculated by the comparison. Whether the calculated difference exceeds the fluctuation reference value is determined by the following determination formula (3): T paper Compared to T ITB 1 if the concentration is increasing, T paper The difference is judged as one of three values: -1 if the concentration is increasing, or 0 if the fluctuation is below the standard. diff Let R diff is performed for each toner color, but the same determination is performed and therefore the explanation will be omitted.

[0082] [Judgment formula 3] T ITB -T paepr >0 and T th < |T ITB -T paepr | Then R diff =1 T ITB -T paepr <0 and T th < |T ITB -T paepr | Then R diff =-1 Other than the above, R diff =0

[0083] Judgment result R diff Once the calculation is completed and stored in the memory 213, the process proceeds to S610.

[0084] In S610, the CPU 212 controls the UI display unit 215 to notify the user of the determination result. A schematic diagram of the screen is shown in FIG.

[0085] Figure 8(a) shows the initial state before the start of a print job. In the initial state, the variation data (color variation information) of the final five pages of the previous print job is displayed. The variation data is displayed for each print page, and displays the job ID, page number, and paper information from the print settings used in the print job. The job ID is a unique identification number for each print job that identifies the print job. The paper information displays information about the paper tray in which the paper was stored, the paper size, and the paper type. An example of paper information is shown as the print setting to be displayed, but it is not limited to the above example. Any of the print settings that can cause variations will suffice, and for example, the screen conditions used in halftone processing, the resolution for RIP processing, and the print orientation may also be displayed.

[0086] By switching the radio buttons in the display settings, it is possible to switch the displayed color and change the displayed variation. FIG. 8(a) shows an example in which the results for K toner are displayed as the display color, and information on color variation on the image carrier 308 and information on color variation on the recording medium 503 are displayed simultaneously. Note that the above display configuration is merely an example and is not limiting. As a more preferred example, an example in which variation on the image carrier and variation on the recording medium are displayed on one screen has been shown, but it is sufficient if only one type of variation is displayed on the screen and the displayed items can be switched by setting. Also, a configuration in which multiple colors are displayed simultaneously is also possible. The colors may be displayed side by side, or the plotted points may be displayed in different colors and overlapped.

[0087] Furthermore, the user may be able to freely change not only the items to be displayed, but also the graph size and layout of each graph for each variation to be displayed. 50% is set as the reference value of 0, and the target toner amount T 50% and the amount of toner on the image carrier T ITB Similarly, the display area 802 shows the relationship between the target toner amount T 50% and the toner amount T on the recording medium paper The display area 803 shows the relationship between the target toner amount T 50% and the toner amount T on the image carrier. ITB and the toner amount T on the recording medium paper In the display area 803, as the creation of the printed matter progresses according to the print job for which printing is instructed, a variation is added for each print page.

[0088] Figure 8(b) shows the print job that has been instructed to print up to five pages. In Figure 8(b), plots are added in real time for each print count, making it possible to notice any fluctuations and make adjustments. In addition, because it is possible to check the fluctuations for multiple jobs side by side, it is easy to compare the presence or absence of fluctuations with the timing of print job switches. For example, if the presence or absence of fluctuations coincides with the switch of print jobs, it suggests that there is a high possibility that changes in print settings such as paper or halftones are affecting the results.

[0089] Also, the reference value 804 is the fluctuation reference value T th From the relationship between the standard and the variation, it is easy to determine whether the variation is at a level that requires adjustment. In this embodiment, as a more preferred example, a process is added to automatically determine whether adjustment measures are required for the printing unit 107 based on the variation for each printing process and the difference between them. The above determination process corresponds to S611 and S612. After updating the display in S610, the process proceeds to S611.

[0090] In step S611, the CPU 212 determines the result R ITB and the judgment result R on the recording medium paper and the difference result Rdiff Based on this, it is determined whether or not a correction means is required for the printing unit 107. ITB , R paper , R diff The determination is made by storing and referencing combination information in advance in the HDD unit 214, which records the presence or absence of a correction means for each combination of values. Table 3 shows an example of the combination information.

[0091] [Table 3]

[0092] As shown in Table 3, ID=1, R on the image carrier ITB There is a color variation in the R on the recording medium. paper If a variation occurs even when the image quality is low, there is a high possibility that the variation is at the stage of the toner image on the intermediate transfer belt 308, which is an image carrier. Therefore, it is desirable to perform gradation correction processing to correct the toner image on the intermediate transfer belt 308. In the above case, in S611, the CPU 214 controls the UI display unit 215 to instruct the user to perform gradation correction processing. FIG. 9 shows an example of a screen that instructs the user in the state of ID=1 in Table 1. As shown in display 901, a gradation correction instruction corresponding to the variation is displayed to the user together with a highlight icon.

[0093] Also, as shown in ID=4 in Table 3, R ITB Although there is no color variation in the R on the recording medium paperIf a density decrease occurs in step S611, there is a high possibility that a variation occurred during the process of transferring the toner image from the intermediate transfer belt 308 to the recording medium. Therefore, it is desirable to perform a secondary transfer voltage adjustment process to adjust the amount of toner in the transfer process. In the above case, in step S611, the CPU 212 controls the UI display unit 215 to instruct the user to perform the secondary transfer voltage adjustment process. For example, in the area corresponding to display 901 in FIG. 9, a secondary transfer voltage adjustment instruction is displayed together with a highlight icon. In many cases, secondary transfer voltage adjustment requires readjustment when the basis weight of the paper differs. Therefore, the user can check the differences in paper for each print job and easily confirm that the adjustment is insufficient.

[0094] Furthermore, as shown in Table 3, ID=5, R ITB Although color variations occur in the R on the recording medium, paper If no color variation occurs in step 1, it is highly likely that adjustments are required in both the toner image forming process and the toner image transferring process. In the above example, it is desirable to correct the toner image formation, which is upstream of the printing process, by gradation correction, and then adjust the toner image transferring process by adjusting the secondary transfer voltage.

[0095] In S612, the CPU 212 controls the UI display unit 215 to instruct the user that gradation correction processing and secondary transfer voltage adjustment processing are necessary and that gradation correction processing should be performed first. Note that the instruction to use an adjustment unit for adjusting color variations described above is merely an example, and the effects of the present invention are not limited to the above example. For example, the CPU 212 may include a configuration for performing adjustments in the process of fixing the toner image on the recording medium 503 if the variations are not reduced even after performing gradation correction and secondary transfer voltage adjustment. Note that in the fixing process, the color can be stabilized by adjusting the temperature of a fixing member (not shown) and the pressure with which the fixing member is pressed against the recording medium 503.

[0096] In this embodiment, an example has been shown in which adjustment instructions are displayed based on the determination results, but the effects of the present invention are not limited to the above example. It is sufficient if measures can be implemented to reduce fluctuations occurring in the printing unit 107 based on the determination results. For example, if the fluctuations exceed a reference value, the printing process in the printing unit 107 may be stopped and an adjustment method may be automatically executed. Furthermore, the items to be presented are not limited to the type of adjustment method. An adjustment value for reducing the fluctuations may be presented based on the fluctuations.

[0097] In S613, the CPU 212 stores the variation data for all pages corresponding to the print job for which a print instruction has been issued in the HDD unit 214. When the data has been stored in the HDD unit 214, the determination process of the image inspection unit 109 ends.

[0098] As described above, the printing unit equipped with multiple image adjustment means is equipped with an acquisition unit that acquires the color on the image carrier 308 during printing processing in addition to the color on the recording medium 503, and acquires the color in multiple processes. Furthermore, the variation is calculated based on the two color variations, and the color variation on the image carrier 308 and the color variation on the recording medium 503 are displayed on the UI. By displaying the color variation on the image carrier 308 and the color variation on the recording medium 503 for multiple print jobs and comparing the variations, the user can grasp in which printing process and print setting the color variation is occurring.

[0099] (Modification of Example 1) In this embodiment, an example has been described in which the fluctuations in the previous print job are displayed in the initial state, but the initial state is not limited to the above example. If the user determines that there is no continuity in the fluctuations from the previous print job, such as immediately after calibration when the print date and time are different, the initial state may be a state in which no fluctuations are displayed, as shown in Figure 8(c). In the above case, it is desirable to provide an option in the color fluctuation detection setting screen that allows the user to select whether or not to display fluctuations in past jobs (jobs that have already been executed), as shown in 701b in Figure 7(b).

[0100] In this embodiment, an example has been described in which the intermediate transfer belt 308 is used as the image carrier, but the image carrier in the present invention is not limited to the above example. Furthermore, any toner image may be used as long as it is a toner image produced in a printing process different from that on the recording medium, and a density sensor may be installed opposite the photosensitive drum to measure the color tone using the photosensitive drum as the image carrier.

[0101] In this embodiment, the color tone is acquired in multiple printing processes and the color tone fluctuations are displayed. However, the displayed fluctuations are not limited to color tone. In this embodiment, for example, the temperature and humidity inside the printing unit 107 are factors that affect color tone. If the color tone fluctuates due to the influence of temperature and humidity, the above-mentioned gradation correction and other measures will not improve the situation. In the above example, it is desirable to install a thermo-hygrometer inside the printing unit 107 and measure the temperature and humidity in real time, and use this as the judgment criteria in S610. Table 4 shows an example of combination information with temperature and humidity added. The difference from Table 3 is that temperature and humidity have been added as judgment criteria. As shown by ID=7, if there is a temperature and humidity fluctuation and fluctuations occur in each printing process, the user is instructed to adjust the room temperature.

[0102] [Table 4]

[0103] In this embodiment, an example has been described in which only patches with an area ratio of 50% are arranged and fluctuations at a specific density are checked, but the density for checking fluctuations is not limited to the above example. It is more desirable to arrange and acquire patches with a plurality of area ratios. For example, 10 patterns from 10% to 100% are acquired in 10% increments, and the displayed density can be switched as shown in 1001 of FIG. 10 .

[0104] In this embodiment, an example has been described in which fluctuations within a print job are displayed in real time, but it is more preferable to have a configuration in which it is possible to check whether past fluctuation results were satisfactory. For example, it is possible to have a function in which the fluctuations displayed in S609 are stored not only in the memory 213 but also in the HDD unit 214, and past fluctuations are displayed on the UI display unit 215 in response to a user instruction.

[0105] Fig. 11 shows an example of a screen when a user specifies information that the user wants to check. A button for changing reference information, such as 1101 in Fig. 11, may be provided, and when the user presses this button, the specification of the information for which the user wants to refer to changes may be accepted, and the changes in the specified information may be displayed on the UI display unit 215. For example, Fig. 11 shows a method for specifying a relative time based on the current time, but it may also be a method that allows specification of an absolute date and time, such as using a calendar, or a method for specification using a print job ID.

[0106] While this embodiment illustrates an example of displaying fluctuations in units of printed pages, the unit of fluctuation display is not limited to the above example. For example, the reference unit for fluctuations may be switched, as shown in 1101c in FIG. 20(a). Pressing the button 1101c displays a pop-up window shown in 1102d, allowing the user to change the reference unit for displaying fluctuations. If the reference unit consists of multiple pages (other than page units), the average value of fluctuations for each page within the reference unit is calculated and displayed as a representative value. More preferably, it is possible to switch to a different calculation method for the representative value, such as a median, maximum, or minimum value, in addition to the reference unit. FIG. 20(b) shows an example display plotting representative values ​​of fluctuations on the image carrier for each printing date. As shown in FIG. 20(b), if the fluctuations are within the standard range but are gradually drifting out of the standard range, it can be confirmed that the corresponding image carrier is deteriorating and needs to be replaced. As described above, when checking the degree of deterioration of parts within the device, it is necessary to check fluctuations over multiple printing processes over a longer period than page units.

[0107] In this embodiment, the example has been described in which the color is acquired from patches made of the same toner image on the image carrier and on the recording medium, but the present invention is not limited to the above example. If the main scanning positions that can be read by the density sensor 310 and the image reading unit 311 are different, the color may be acquired from different patches under the same printing conditions.

[0108] Examples of acquiring color from different patches are shown in FIGS. 12 and 13. FIG. 12 shows the same conditions as FIG. 4, and FIG. 13 shows the same conditions as FIG. 5. For example, the density sensor 310 can perform measurements near the center of the image carrier. If the image reading unit 311 can perform measurements only at the end of the transport path, the patches for acquiring color may be separated as shown in 501 and 504 in FIG. 12. Patch 501 acquires color on the image carrier, and patch 504 acquires color on the recording medium 503. In the above case, as shown in FIG. 13, it is desirable that patches for acquiring color only on the image carrier not be formed on the recording medium 503.

[0109] In this embodiment, the image forming apparatus 101 is provided with multiple display units (UI display units 202, 215), and the print job settings are performed on the UI display unit 202, and the changes are displayed on the UI display unit 215. However, the combination of displayed items and display units is not limited to the above example. For example, if the only display unit available is the UI display unit 202, all items may be displayed on a single display unit.

[0110] Example 2 The color acquisition process according to this embodiment will now be described. In the first embodiment, an example was described in which a patch 501 for acquiring a color was formed on a recording medium 503. However, the effects of the present invention are not limited to the above example. For example, there may be cases in which a toner image 502 based on input image data occupies a large proportion of the recording medium 503, making it impossible to position the patch 501 on the recording medium 503. In such cases, it is desirable to acquire a color from a toner image based on the input image data and check for variations.

[0111] The processing in the image inspection unit 109 according to the second embodiment will be described with reference to FIG. 14. As in the first embodiment, FIG. 14 is a flowchart showing the processing procedure in which the image inspection unit 109 calculates the color variation during a print job executed by the printing unit 107 and displays the result, as in the first embodiment. Two steps, S1402 and S1409, differ from the first embodiment. In S1402, the user specifies a position on the recording medium 504 from which the color is acquired from the input image data. In S1409, information that can be compared with the color on the image carrier is estimated from the acquired color. Note that the printing system and functional configuration according to the second embodiment are the same as those of the first embodiment, and therefore their description will be omitted. The processing in S1402 and S1409, which differs from the first embodiment, will be described. The processing in S1402 is executed by the CPU 206 of the printing unit 107, and the processing in S1409 is executed by the CPU 212 of the image inspection unit 109.

[0112] In S1402, the CPU 206 accepts an instruction for a position on the recording medium 504 from which to acquire color based on an instruction from the user on the UI display unit 202. FIG. 15 shows a schematic diagram of a screen for accepting instructions from the user. When color variation detection is set on the setting screen shown in FIG. 7, the CPU 206 controls the UI display unit 202 to display the screen shown in FIG. 15. As shown in FIG. 15, a preview of the image data entered by the user is displayed, and the user is prompted to specify a position from which to acquire color. The user selects a method for specifying the position from a task bar 1501. For example, the user can select a method such as specifying the center position of the measurement position with a cursor, a rectangle, or a circle. FIG. 15 shows an example of specifying with a cursor. The user moves a cursor 1502 on the preview screen to specify a position. When an instruction from the user is received, the position is notified to the user with a highlighted rectangle 1503.

[0113] When the CPU 206 confirms that the user has pressed the OK button, it stores the last-specified position in the memory 207 as the position on the recording medium 504 where the color is to be measured, and proceeds to step S1403. While the present embodiment illustrates an example in which the user specifies one position, this is not limited to this example. Acquiring multiple positions allows for more stable color variation to be obtained. It is desirable to set an upper limit based on the number of areas that can be acquired by the image reading unit 311 while the recording medium 304 is being conveyed. While the example in which the user specifies the area has been described, the method for specifying the acquisition area is not limited to this example. As shown by 1504 in FIG. 15 , the CPU 206 may be configured to automatically select an area based on input image data. It is desirable for the acquisition area to have the same printing conditions (toner combination, area ratio) as the patch 501 on the image carrier from which the color is to be acquired. For example, it may be configured to automatically select an area that is close to the printing conditions included in the patch 501.

[0114] In S1409, the image inspection unit 109 estimates the amount of toner on the recording medium 304 from the acquired RGB values ​​under the same printing conditions as the patch 501 that acquires the color on the image carrier. FIGS. 16 and 17 are schematic diagrams showing how the color is acquired in the second embodiment. FIG. 16 is a diagram showing the same conditions as FIG. 4, and FIG. 17 is a diagram showing the same conditions as FIG. 5. In the second embodiment, the patch 501 shown in FIG. 16 acquires the color on the image carrier. As shown in FIG. 17(b), the color on the recording medium 503 is acquired at the position specified by the user in S1402. As shown in FIG. 17, in the second embodiment, the patch that acquires the color on the image carrier is not formed on the recording medium 503.

[0115] In S1409, unlike S608, the color tone in the mixed color area consisting of multiple toners is acquired, so the toner amount is calculated using a color conversion method different from that in S608. First, the RGB values ​​are converted into the device-independent Lab color space. Then, the T that represents the device-dependent toner amount is converted from the device-independent Lab. CMYK Each color conversion is performed using a 3D LUT similar to the format described above. CMYKThe conversion to uses the same 3D LUT as that used when converting input image data to a toner image. By converting to a device-independent color space once and then calculating the toner amount using the same conversion as the input image data, it becomes possible to calculate the toner amount with high accuracy even from a mixed color area. Next, the calculated toner amount T CMYK From this, the toner amount T on the image carrier 308 taking into account the engine condition is calculated. out Estimate.

[0116] In this embodiment, the engine state is the input toner amount T in and the toner amount T actually recorded on the recording medium 304 out The engine condition changes depending on the temperature and humidity inside the machine and the timing of toner cartridge replacement. Several possible engine conditions are stored, and the toner amount T calculated using the 3D LUT is CMYK The engine state closest to the toner amount T is searched for and determined to be the current engine state. The engine state is estimated for each toner color. k This will be explained using the following example.

[0117] First, an example of determining the engine state will be described. A diagram showing a plurality of engine states stored in advance is shown in FIG. 18(a). If the engine state is close to the reference state, as shown in 1801, the toner amount T in and the toner amount T on the recording medium 503 out In the above engine state, the input toner amount T in the area specified by the user in the input image data is in a linear relationship. image and T calculated using 3D LUT k The engine state that is closest to the relationship between the input toner amount and T image On the axis (1802), the value T k In the example of FIG. 18(a), T image The toner image of T = 75 was formed on the recording medium 503, but the amount of toner on the recording medium 503 acquired by the image reading unit 311 was T kThis shows a schematic example of the 1802 axis. image =75 and T k The engine state 1804 closest to the intersection with =160 is determined to be the current engine state.

[0118] Next, based on the engine status searched, the area ratio is set to 50% (toner amount T patch =128) on the recording medium 304 out An example of the estimation is shown in FIG. 18(b). patch = 128 out In the example of FIG. 18(b), T patch = 128 as the corresponding value of T out = 200. T out The estimation is performed for each toner color, and the estimated values ​​for all toner colors are stored in memory 213, and the process proceeds to S1410. The processing from S1410 onwards is the same as in the first embodiment, so a description thereof will be omitted. As in the first embodiment, the processing from S1404 to S1413 is performed on a page-by-page basis. If the print job is data consisting of multiple pages, S1404 to S1413 are repeatedly executed for each page until printing of all pages included in the print job is completed. When printing is completed, finally, as in the first embodiment, the variation data for all pages corresponding to the print job for which a print instruction was issued is saved in HDD unit 214.

[0119] As explained above, an example has been described in which the color on the recording medium 503 is acquired from the toner image corresponding to the input image data when the toner image 502 based on the input image data occupies a large proportion of the recording medium 503. The color under the same printing conditions is estimated from the input image toner image, which is under different printing conditions from the patch toner image on the image carrier 308. By adding the above estimation means, even when the toner image 502 based on the input image data occupies a large proportion of the recording medium 503, the color variation on the image carrier 308 and the color variation on the recording medium 503 are displayed, allowing the user to compare the variations. As a result, the user can compare variations across multiple print jobs and determine which printing process or printing setting is causing the color variation.

[0120] In this embodiment, an example has been described in which a color tone under the same printing conditions as the patch toner image is estimated from an input image toner image under different printing conditions. However, the effects of the present invention are not limited to the above example. The printing conditions for forming the patch toner image may be changed based on the printing conditions of an area selected by the user. In the above example, when an area designation is received from the user in S1402, the CPU 206 changes the printing conditions of the patch toner image so that the printing conditions within the area match the printing conditions of the patch toner image formed in S1403, and stores the changes in the memory 207.

[0121] Furthermore, in this embodiment, an example has been described in which color under the same printing conditions is estimated from an input image toner image under different printing conditions than the patch toner image, and color variation under the same conditions is displayed, but the printing conditions that can be displayed are not limited to the above. In addition to color variation under the same conditions, it is desirable to be able to display color variation under printing conditions in an area specified by the user that are different from the patch toner image. In addition to comparing color variation under the same printing conditions on the image carrier 308 and the recording medium 503, comparing color variation under different printing conditions on the recording medium makes it possible to further narrow down the causes of variation.

[0122] (Other Examples) In the first and second embodiments, examples have been described in which the respective variations and differences are displayed side by side, but the present invention is not limited to the above examples. As shown in the schematic diagram of Fig. 19, the variations and differences in the respective printing processes may be displayed in different ways and overlaid. Furthermore, a more suitable display method may be a display method in which the presence or absence of variations in the most recently printed page or the direction of the variations (density up, density down) is displayed with an icon, as shown in the schematic diagram of the screen 2001 in Fig. 20, allowing the user to easily check the display.

[0123] Although the example of displaying paper information as a difference in print settings for each print job has been described, it would be more desirable to be able to check differences in information such as halftone processing conditions during printing and RIP resolution. For example, as shown in Fig. 21, it is desirable to have a configuration in which details of the print settings are displayed in a pop-up when the user places the operation cursor over the variable display section. By displaying the pop-up, it becomes possible to identify variation factors taking into account differences in print settings other than paper conditions.

[0124] The present invention may be applied to a system consisting of multiple devices, such as a host computer, interface device, reader, and printer, or may be applied to an apparatus consisting of a single device, such as a copier or facsimile machine.

[0125] 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.

[0126] (Other Examples) While various examples and embodiments of the present invention have been shown and described, the spirit and scope of the present invention should not be limited to the specific descriptions herein.

[0127] 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. It can also be realized by a circuit (e.g., ASIC) that realizes one or more functions. [Explanation of symbols]

[0128] 101 Image forming device 107 Printing Department 108 Diagnostic Department 310 Concentration Sensor 331 Image reading unit

Claims

1. a printing means for printing on a recording medium in accordance with an input print job; a first acquisition means for acquiring a first color on an image carrier during printing; a second acquisition means for acquiring a second color tone on the printed recording medium; a display means for displaying color variation information based on the acquired color; the first acquisition means acquires at least a first color tone of a first print job and a second print job; the second acquisition means acquires at least a second color tone of the first print job and a second print job; The display unit displays first color variation information based on the first color of at least the first print job and the second print job, and second color variation information based on the second color of at least the first print job and the second print job. An image forming apparatus characterized by:

2. a first calculation means for calculating a difference between the first color tone of at least the first print job and the second print job acquired by the first acquisition means and a first reference value; a second calculation unit that calculates a difference between the second color values ​​of at least the first print job and the second print job acquired by the second acquisition unit and a second reference value, the first color variation information includes at least the difference calculated by the first calculation means and corresponding to each of the first print job and the second print job; the second color variation information includes at least a difference calculated by the second calculation means and corresponding to each of the first print job and the second print job; 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

3. a storage unit that stores the difference of the first print job calculated by the first calculation unit and included in the first color variation information, and the difference of the first print job calculated by the second calculation unit and included in the second color variation information; 3. The image forming apparatus according to claim 2, wherein the image forming apparatus is a recording medium.

4. the first print job is a print job that has already been executed; The second print job is a running print job.

4. The image forming apparatus according to claim 3, wherein the image forming apparatus is a recording medium.

5. The display means displays third color variation information which is a difference between the first color variation information and the second color variation information.

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

6. the first color and the second color include at least one of a toner amount, a density, a brightness, a saturation, and a hue; The image forming apparatus according to claim 1 .

7. the first color variation information and the second color variation information include at least one of a difference between a reference value and a toner amount, a difference between a reference value and a density, a difference in brightness from a reference value, a difference in saturation from a reference value, a difference in hue from a reference value, and a difference in color from a reference value; The image forming apparatus according to claim 1 .

8. further comprising image adjustment means for making one or more adjustments to stabilize the color of the print; 6. The image forming apparatus according to claim 5, further comprising: a determining unit that determines the necessity of the one or more adjustments by the image adjusting unit based on the third color variation information.

9. 9. The image forming apparatus according to claim 8, wherein the image adjusting unit performs at least one of maximum density correction, tone correction, and secondary transfer voltage adjustment for each toner color.

10. 2. The image forming apparatus according to claim 1, wherein the first acquisition means acquires the first color from a patch toner image contained in a toner image on the image carrier, and the second acquisition means acquires the second color from a patch printed on the recording medium.

11. The image forming apparatus further includes a third acquisition unit for acquiring the temperature or humidity inside the image forming apparatus, the determining means determines the necessity of one or more adjustments by the image adjusting means based on the first color variation information and the second color variation information as well as temperature or humidity. The image forming apparatus according to claim 8 .

12. 2. The image forming apparatus according to claim 1, wherein said display means changes the toner color and toner density to be displayed in accordance with a user's designation or color variation information.

13. 2. The image forming apparatus according to claim 1, wherein the first color variation information and the second color variation information are referenced in units of one or more of a page, a print job, and a print date and time.

14. 2. The image forming apparatus according to claim 1, wherein the first acquisition unit and the second acquisition unit acquire the color tone from different patch toner images.

15. the display means has a plurality of display areas, The first color variation information and the second color variation information are displayed in different display areas of the display means. The image forming apparatus according to claim 1 .

16. acquiring a color tone from a position of an input image toner image corresponding to the image data included in the print job, in accordance with the printing conditions of the patch toner image on the image carrier; The image forming apparatus according to claim 1 .

17. changing the printing conditions of the patch toner image on the image carrier in accordance with the printing conditions of the position where the color tone of the input image toner image corresponding to the image data included in the print job is acquired; The image forming apparatus according to claim 1 .

18. 2. The image forming apparatus according to claim 1, wherein said display means has a plurality of icons corresponding to variations in the values ​​of said first color variation information and said second color variation information, and displays said icons corresponding to the variations.

19. 1. A display method for an image forming apparatus having a printing unit that prints on a recording medium in accordance with an input print job, comprising: The first acquisition means acquires a first color on the image carrier during printing processing in the first print job and the second print job; a second acquisition unit acquires a second color on the recording medium printed in the first print job and the second print job; The display means for displaying color variation information based on the acquired color displays first color variation information based on the first color of at least the first print job and the second print job, and second color variation information based on the second color of at least the first print job and the second print job. A display method for an image forming apparatus.

Images