Color verification device, color verification method, and image forming system

Abstract

To provide a color verification device that can conduct a verification as to whether a difference in color between a plurality of printers is within a predetermined allowable range, while satisfying a color standard.SOLUTION: A color verification device 100 comprises a color verification calculation unit that determines whether a color verification target satisfies verification conditions set for a plurality of color targets, and as the plurality of color targets, a color target calculated by using a target profile and a color target of a color verification target are provided. The color verification calculation unit determines that the color verification target passes the verification when the color verification target satisfies all the verification conditions for the plurality of color targets.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a color verification device, a color verification method, and an image forming system. [Background technology]

[0002] A technology related to color verification for ensuring the color level of an image forming device is disclosed in Patent Document 1 below. Patent Document 1 states, "In step S301, (one or more) color patch charts (or multiple measurement sheets) are printed. In step S302, the (one or more) printed color patch charts are automatically measured by a colorimeter. In step S303, it is determined whether the command from the server includes a target. If the command does not include a target (i.e., 'no'), the process continues to step S305, where the printer's color parameters are calculated and / or corrected based on the measured data and the first target. If the command includes a target, in step S304, the printer's color parameters are calculated and / or corrected based on the measured data and / or the target sent from the server." [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-182780 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the technology of Patent Document 1, the color parameters of the printer are calculated and / or corrected based on only one of the first target and the target sent from the server. Therefore, although this technology can eliminate color differences between multiple printers, it cannot verify whether the printed colors of each printer are within the allowable range of the color standard.

[0005] Therefore, an object of the present invention is to provide a color verification device and a color verification method that can verify whether the color differences between multiple printers are within a specified tolerance range while satisfying color standards, and to provide an image forming system equipped with this color verification device. [Means for solving the problem]

[0006] To achieve this goal, the present invention provides a color verification device equipped with a color verification calculation unit that determines whether a color verification object satisfies verification conditions set for a plurality of color targets. [Effects of the Invention]

[0007] The present invention provides a color verification device and a color verification method that can verify whether color differences between multiple printers are within a specified tolerance range while satisfying color standards, and also provides an image forming system equipped with this color verification device. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a configuration diagram of an image forming system equipped with a color verification device according to an embodiment. [Figure 2] FIG. 2 is a block diagram of a color verification device according to the embodiment. [Figure 3] FIG. 3 is a diagram for explaining the settings for color verification in the color verification device according to the embodiment. [Figure 4] FIG. 4 is a diagram showing an example of a display of a color verification result in the color verification device according to the embodiment. [Figure 5] FIG. 5 is a diagram showing an example of a color measurement chart. [Figure 6] FIG. 6 is a diagram showing an example of patch information for printing a color measurement chart. [Figure 7] FIG. 7 is a flowchart showing a color verification method according to an embodiment. [Figure 8]FIG. 8 is a diagram showing an example of the color measurement results of a color measurement chart printed by a color verification printer. [Figure 9] FIG. 9 is a diagram showing a first example of a color target used in the embodiment. [Figure 10] FIG. 10 is a diagram showing a second example of a color target used in the embodiment. [Figure 11] FIG. 11 is a diagram illustrating an example of a calculation result in the color verification device according to the embodiment. [Figure 12] FIG. 12 is a diagram for explaining color verification by the color verification device of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the embodiments described below, the same components are designated by the same reference numerals, and duplicated descriptions will be omitted.

[0010] <Image forming system> Fig. 1 is a configuration diagram of an image forming system 1 including a color verification device 100 according to an embodiment. The image forming system 1 shown in Fig. 1 includes a plurality of printers 10, a colorimeter 20, a control device 30, and a wired or wireless network 40 connecting these devices. The colorimeter 20 may be connected to the control device 30 via an interface such as a USB (Universal Serial Bus).

[0011] The control device 30 constitutes the color verification device 100 and includes a display unit, an operation unit, and a calculator. The calculator is hardware used as a so-called computer, and includes a CPU (Central Processing Unit), non-volatile storage units such as RAM (Random Access Memory) and ROM (Read Only Memory), as well as a network interface. Next, the configuration of the color verification device 100 included in the image forming system 1 will be described.

[0012] <Color verification device 100> Fig. 2 is a block diagram of a color verification device 100 according to an embodiment. As shown in Fig. 2, the color verification device 100 includes a user interface 101, a color verification processing unit 102, and a data storage unit 103. These are as follows:

[0013] [User Interface 101] The user interface 101 includes a verification condition setting section 101a and a verification result display section 101b, which are configured by the display section and operation section of the control device 30.

[0014] Of these, the verification condition setting unit 101a displays a setting screen for color verification on the display unit of the control device 30, and enables the user to perform various settings by operating the operation unit. Fig. 3 is a diagram for explaining the setting of color verification in the color verification device of the embodiment, showing a setting screen [P1] displayed on the display unit of the control device 30 (see Fig. 1).

[0015] 3, the setting screen [P1] displays a color verification setting section 1001 and tolerance setting sections 1002 and 1003. Of these, the color verification setting section 1001 displays a setting section for a color measurement chart and a setting section for multiple color targets (color targets 1 and 2) as color verification settings. The multiple color targets are, for example, a target profile and a color verification target.

[0016] Here, in the color measurement chart setting section, one color measurement chart to be used for color verification is selected from one or more color charts for color measurement. In the target profile (color target) setting section, one target profile is selected from one or more color profiles. Also, in the color verification target (color target) setting section, an arbitrary reference printer 10a (see FIG. 1) is selected from the multiple printers 10 to be used as the color target.

[0017] Furthermore, the tolerance setting units 1002 and 1003 set the calculation method for color difference (dE) and the tolerance for color difference (dE) for each color target. Here, color difference (dE) refers to the color difference (dE) between the target value of each color target set in the color verification setting unit 1001 and the color measurement value of the color measurement chart printed by the color verification printer 10b (see FIG. 1) that is the target of color verification. There are calculation methods for color difference (dE), such as ΔE*ab and ΔE*00. The simplest ΔE*ab is ΔE*ab=[(ΔL*) 2 +(Δa*) 2 +(Δb*) 2 ] 1 / 2 The allowable value of the color difference (dE) is, for example, a threshold value for each of the average value and the maximum value.

[0018] 2, the verification result display unit 101b of the user interface 101 displays the verification results of the color verification on the display unit of the control device 30. Fig. 4 is a diagram showing an example of the display of the color verification results in the color verification device of the embodiment, and shows verification result screens [P2] and [P2'] displayed on the display unit of the control device 30 (see Fig. 1).

[0019] As shown in FIG. 4, the verification result screens [P2] and [P2'] display the results of color verification performed by the color verification processing unit 102 (see FIG. 2), which will be described next, for a specific color verification printer 10b selected from multiple printers 10 (see FIG. 1). These verification result screens [P2] and [P2'] display the tolerances for each color target, calculated values, the results of judgment for each item, and the overall judgment result. The tolerances for each color target are values set on the setting screen [P1] (see FIG. 3), such as the average and maximum color difference (dE). The calculated values are the calculation results of the average and maximum color difference (dE) between the colorimetric values of the color measurement chart printed by the color verification printer 10b and the target values of each color target. The judgment result is the result of judging for each item whether the calculated value is within the tolerance range. The overall judgment result is a comprehensive judgment result based on the judgment results for each item. For example, a pass is displayed only if all the judgment results for each item are pass, and a fail is displayed otherwise.

[0020] [Color verification processing unit 102] Returning to FIG. 2, the color verification processing unit 102 includes a chart printing instruction unit 102a, which is configured by the computer of the control device 30, a color measurement value acquisition unit 102b, and a color verification calculation unit 102c.

[0021] Of these, the chart printing instruction unit 102a instructs the color verification printer 10b (see FIG. 1) to print the colorimetric chart set by the verification condition setting unit 101a, for example, based on a user's operation of the control device 30. The colorimetric value acquisition unit 102b acquires the colorimetric values of the colorimetric chart from the colorimeter 20. The color verification calculation unit 102c then performs color verification for the color verification printer 10b based on the colorimetric values acquired by the colorimetric value acquisition unit 102b and the various data stored in the data storage unit 103, which will be described next. The detailed procedure for color verification by the color verification processing unit 102 will be described below in the color verification method section.

[0022] [Data storage unit 103] The data storage unit 103 includes a color measurement chart storage unit 103a, a target profile storage unit 103b, a color verification target storage unit 103c, and a color verification setting storage unit 103d, which are configured by the storage unit of the control device 30.

[0023] Of these, the color measurement chart storage unit 103a stores information related to the color measurement chart. The information related to the color measurement chart stored here includes chart images of one or more types of color charts for color measurement that can be selected on the setting screen [P1] (see FIG. 3), and color information for causing the printer 10 to print the chart images.

[0024] Fig. 5 is a diagram showing an example of a color measurement chart (color chart). Fig. 6 is a diagram showing an example of patch information for printing the color measurement chart, which is color information for printing the color measurement chart shown in Fig. 5. The patch information (color information) shown in Fig. 5 has the supply amount of color material for each of the CMYK colors for each patch 1A, 1B, 1C, ... of the color measurement chart.

[0025] Returning to FIG. 2, the target profile storage unit 103b stores a target profile that is one of multiple color targets. The target profile is a color profile (Japan Color, Fogra, etc.) that defines a color standard. The target profile storage unit 103b stores one or more types of target profiles that can be selected on the setting screen [P1] (see FIG. 3).

[0026] The color verification target holding unit 103c also holds, as second target values, the colorimetric values (Lab values) obtained by measuring each patch of the colorimetric chart printed by the reference printer 10a (see FIG. 1) with the colorimeter 20. If there are multiple colorimetric charts that can be selected on the setting screen [P1] (see FIG. 3), the color verification target holding unit 103c holds at least the colorimetric values of the colorimetric chart selected on the setting screen [P1].

[0027] The color verification setting storage unit 103d stores various setting information related to color verification set by the user on the setting screen [P1] shown in FIG.

[0028] <Color verification method> Figure 7 is a flowchart showing a color verification method according to an embodiment. The color verification method shown in this flowchart is a procedure for printer color verification carried out in accordance with a program stored in the color verification device 100 shown in Figures 1 and 2, and includes some steps carried out by a user. The color verification method will be explained below in accordance with the procedure shown in Figure 7, using Figures 1 to 6 and other necessary figures. This flow can be started at any time by a user of the image forming system 1 operating the control device 30.

[0029] [Step S101] In step S101, the chart printing instruction unit 102a instructs the color verification printer 10b (see FIG. 1) selected by the user to print a color measurement chart. At this time, the chart printing instruction unit 102a extracts information about the color measurement chart set on the setting screen [P1] (see FIG. 3) from the color measurement chart storage unit 103a based on the color verification settings stored in the color verification setting storage unit 103d. Then, the extracted information, i.e., the chart image and color information (patch information) of the color measurement chart, is sent to the color verification printer 10b. This causes the color verification printer 10b to print the color measurement chart.

[0030] [Step S102] In step S102, the colorimetric value acquisition unit 102b acquires the colorimetric values of each patch of the colorimetric chart printed by the color verification printer 10b from the colorimetric device 20. Note that the colorimetric measurement of the colorimetric chart using the colorimetric device 20 is performed by the user. FIG. 8 is a diagram showing an example of the colorimetric results of a colorimetric chart printed by the color verification printer, and shows the results when the colorimetric chart shown in FIG. 5 is printed. As shown in FIG. 8, the colorimetric results of the colorimetric device are expressed as colorimetric values for each patch, for example, in Lab values.

[0031] [Step S103] In step S103, the color verification calculation unit 102c calculates a color target using the target profile set on the setting screen [P1] (see FIG. 3). At this time, the color verification calculation unit 102c extracts the target profile set on the setting screen [P1] (see FIG. 3) from the target profile storage unit 103b based on the color verification settings stored in the color verification setting storage unit 103d. Then, based on the YMCK values of the patch information (color information) of the color measurement chart extracted in step S101, the color verification calculation unit 102c calculates the chromaticity (Lab value) of each patch in the color measurement chart using the extracted target profile, and sets this as a first target value (color target).

[0032] 9 is a diagram showing a first example of a color target used in the embodiment, which shows a color target calculated using a target profile. As shown in Fig. 9, in step S103, the target profile is used to calculate, for example, Lab values corresponding to each patch of the color measurement chart shown in Fig. 3 as first target values (color targets).

[0033] [Step S104] In step S104, the color verification calculation unit 102c performs color verification using the color target calculated in step S103. First, the color verification calculation unit 102c calculates the color difference (dE) between the color target (first target value) calculated in step S103 and the colorimetric value acquired in step S102. At this time, the color verification processing unit 102 calculates the color difference (dE) of each patch using the color difference (dE) calculation method set in the target profile tolerance setting unit 1002 on the setting screen [P1] (see FIG. 3). Next, the color verification processing unit 102 extracts the maximum value of the calculated color differences (dE) of each patch and calculates the average value of the color differences (dE).

[0034] [Step S105] In step S105, the color verification calculation unit 102c performs color verification using the set color verification target. First, the color verification calculation unit 102c calculates the color difference (dE) between the color measurement values of the color measurement chart printed by the reference printer 10a (see FIG. 1), which serves as the color verification target, and the color measurement values acquired in step S102. In this process, the color verification calculation unit extracts the color measurement values corresponding to the color measurement chart set on the setting screen [P1] (see FIG. 3) from the color verification target storage unit 103c and sets them as second target values. FIG. 10 is a diagram showing a second example of a color target used in this embodiment, and is an example of the color verification target (second target value) extracted from the color verification target storage unit 103c. The color verification processing unit 102 calculates the color difference (dE) of each patch using the color difference (dE) calculation method set in the color verification target tolerance setting unit 1003 on the setting screen [P1] (see FIG. 3). Next, the color verification processing unit 102 extracts the maximum value of the calculated color difference (dE) of each patch, and calculates the average value of the color difference (dE).

[0035] [Step S106] In step S106, the color verification calculation unit 102c performs color verification based on the calculated values calculated in step S104, the calculated values calculated in step S105, and the setting conditions set on the setting screen [P1] (see FIG. 3). FIG. 11 is a diagram showing an example of calculated values calculated by the color verification device of the embodiment. As shown in FIG. 11, the color verification calculation unit 102c of the color verification device 10 calculates the color difference for each patch between the colorimetric value acquired in step S102 and the first target value calculated in step S104, and the color difference for each patch between the colorimetric value acquired in step S102 and the second target value calculated in step S105. The maximum and average color differences for each patch are also calculated.

[0036] The color verification calculation unit 102c determines whether the calculated maximum and average values shown in Fig. 11 are within the allowable ranges of the maximum and average values set on the setting screen [P1] (see Fig. 3). If all are within the range, it is judged as passed, but if even one calculated value is not within the range, it is judged as failed.

[0037] 12 is a diagram for explaining color verification by a color verification device according to an embodiment of the invention, illustrating a conceptual image of color verification based on the colorimetric values of a color measurement chart printed by the color verification printer 10b (see FIG. 1). The colorimetric values are actually three-dimensional (L, a, and b), but are depicted in two dimensions for illustrative purposes. In step S106, the color verification calculation unit 102c determines that a range [R12] that satisfies both the color target [T1] based on the target profile and its tolerance range [R1], and the color target [T2] of the color verification target and its tolerance range [R2] is acceptable.

[0038] [Step S107] In step S107, the verification result display unit 101b displays the judgment result from step S106 on the display unit of the control device 30, as shown in FIG. 4. FIG. 4 illustrates two judgment results, and the verification result screen [P2] shows a case where all calculated values are within the allowable range and the overall judgment is pass. On the other hand, the verification result screen [P2'] shows a case where the calculated value of the average value of the color verification target (second target value) exceeds the allowable value and the average value item is fail, resulting in an overall judgment of fail. This allows the user of this image forming system 1 to adjust the color verification printer 10b or to urge maintenance personnel to make adjustments if the overall judgment is fail.

[0039] <Effects of the embodiment> According to the embodiment described above, color difference tolerances are set for two color targets, and the pass / fail of color verification is determined based on whether the color measurement values of the color measurement chart printed by the color verification printer 10b meet both tolerances. By setting one of the two color targets based on the target profile and the other based on the colors printed by the reference printer 10a, it is possible to verify whether the color differences between printers are within a predetermined tolerance while meeting the color standard. Furthermore, by adjusting the color verification printer 10b based on the verification results, it is possible to form images that meet the color standard and suppress the color differences between multiple printers within a predetermined tolerance. Furthermore, based on the verification results and the printing history of the color verification printer 10b, it is possible to estimate the trend (number of remaining prints and time) until the printed colors of the color verification printer 10b deviate from the tolerance range of the target colors (range [R12] shown in FIG. 12).

[0040] In the above-described embodiment, color verification is performed using one of the printers 10 included in the image forming system 1 as the color verification printer 10b. However, the user can select multiple printers 10 as the color verification printer 10b. In this case, the color verification device 10 performs color verification under the same conditions for the multiple color verification printers 10b selected by the user. Here, the same conditions mean that the color measurement chart (color chart), color target, and color verification conditions printed by each color verification printer 10b are the same. As a result, when performing distributed printing using multiple printers 10, by setting all of the printers 10 used in distributed printing as color verification printers 10b and performing color verification, distributed printing can be performed that meets color standards while ensuring color uniformity.

[0041] In the above-described embodiment, a color verification method was described in which, for each color target, all patches on a color measurement chart (color chart) are targeted to determine whether the calculated color difference (dE) value is within the same tolerance range. However, the color verification method of the present invention may also set a tolerance value for each patch on a color measurement chart. For example, in the color measurement chart shown in FIG. 5, for gray patches where color differences are particularly noticeable, the tolerance value for color difference (dE) may be set to a narrower range than for other patches.

[0042] Furthermore, the color verification device 100 may include a color adjustment unit that adjusts the print colors of the color verification printer 10b based on the calculation results of the color verification calculation unit 102c. The color adjustment unit adjusts the color information for printing by the color verification printer 10b based on the calculation results of the color verification calculation unit 102c so that the print colors of the color verification printer 10b fall within the ranges of two target colors.

[0043] Furthermore, the color verification device 100 may include a verification result storage unit that stores the color verification results from the color verification calculation unit 102c in the data storage unit 100. The verification result storage unit does not necessarily have to be provided in the verification device 100, but may be provided on a cloud to which the color verification device 100 can connect. [Explanation of symbols]

[0044] 1...Image forming system 10. Printer 10a...Reference printer 10b...Color verification printer 20...colorimeter 100...Color verification device 101a...Verification condition setting section 102c...Color verification calculation section

Claims

1. A color verification calculation unit is provided to determine whether the color verification object satisfies the verification conditions set for a plurality of color targets. Color verification device.

2. The color verification calculation unit determines whether the color difference between the color verification object and each of the color targets satisfies a color difference tolerance set for each of the color targets. The color verification device according to claim 1 .

3. The plurality of color targets are a target profile and a color verification target. The color verification device according to claim 1 .

4. a verification condition setting unit for setting the verification condition, The color verification calculation unit determines whether the verification conditions set by the verification condition setting unit are satisfied. The color verification device according to claim 1 .

5. The verification condition setting unit allows the setting of a tolerance for color difference between the color verification target and each of the color targets and a method for calculating the color difference as the verification conditions. The color verification device according to claim 4 .

6. The color difference tolerance is set for each of the color targets. The color verification device according to claim 5 .

7. The color verification calculation unit determines that the color verification object is acceptable if it satisfies all of the verification conditions set for the plurality of color targets. The color verification device according to claim 1 .

8. the color verification object is a color chart printed by a color verification printer, The plurality of color targets are a color profile and a color chart printed by a reference printer. The color verification device according to claim 1 .

9. The color verification calculation unit makes a determination based on the color measurement values of the color chart printed by the color verification printer, the color measurement values of the color chart printed by the reference printer, and the chromaticity of the color chart calculated based on the color profile. The color verification device according to claim 8 .

10. The color verification calculation unit calculating a color difference between each patch of the color chart to be subjected to color verification and each patch of the color chart calculated based on a color profile that is one of the plurality of color targets; calculating a color difference between each patch of the color chart to be subjected to color verification and each patch of one of the plurality of color targets; It is determined whether or not each of the calculated color differences satisfies the allowable color difference values set for each of the color targets. The color verification device according to claim 9 .

11. a verification condition setting unit that can set the verification condition for each patch; The color verification calculation unit determines whether or not each patch satisfies the verification condition set by the verification condition setting unit. The color verification device according to claim 10.

12. a color adjustment unit that adjusts the color of the color verification printer based on the verification result of the color verification calculation unit; The color verification device according to claim 8 .

13. a verification result storage unit that stores the verification result of the color verification calculation unit; The color verification device according to claim 1 .

14. The color verification calculation unit determines whether the color verification target satisfies the verification conditions set for the multiple color targets. Color verification method.

15. the color verification object is a color chart printed by a color verification printer, The color verification calculation unit performs color verification of each color chart printed by the plurality of color verification printers. The color verification method of claim 14.

16. For each of the color charts, color verification is performed under the same color target and the same color verification conditions. The color verification method of claim 15.

17. Multiple printers and a color verification device that performs color verification of the color verification printer set to any one of the plurality of printers, The color verification device includes a color verification calculation unit that determines whether the color chart printed by the color verification printer satisfies verification conditions set for a plurality of color targets. Imaging system.

18. a colorimeter for measuring the color of the color chart; The color verification calculation unit makes the determination based on the color measurement value measured by the colorimeter.

18. The imaging system of claim 17.

Images