JP6922967B2 - Color patch generator, image forming device and program - Google Patents

Description

The present invention relates to a color patch generator, an image forming apparatus, and a program.

In an image forming apparatus such as a printer, in order to periodically check whether or not the image forming apparatus is in a normal state without color shift, it is conceivable to read the print result of the image forming apparatus with a colorimeter and acquire a Lab value. However, it is complicated because the color measurement is a manual operation. Therefore, it has been proposed that the print result is automatically read by an in-license sensor or the like of an image forming apparatus instead of a colorimeter to acquire an RGB value, and the RGB value is converted into a Lab value.

Patent Document 1 has an object of improving the efficiency of generating color conversion information used for color conversion while reducing the influence on the accuracy of color conversion, and prints a color patch to acquire RGB values, and obtains RGB values. It is described that the patch data is deleted so that the number of the above is a predetermined number, the remaining patch is color-measured to obtain the Lab value, and the color prediction model is generated using the obtained RGB and the Lab value. Has been done.

Japanese Unexamined Patent Publication No. 2012-248934

An object of the present invention is to obtain a first color such as an RGB value on the same paper without measuring a plurality of color patches as they are with a colorimeter to obtain a first color space value such as an RGB value. It is an object of the present invention to provide an apparatus and a program for acquiring a second color space value such as a space value and a Lab value.

The invention according to claim 1 is for acquiring a first color space value which is a device-dependent color space of an image forming apparatus for reading a color patch, and is a second device-independent color space of the image forming apparatus. The printing unit includes a printing unit that prints a color patch that is not for acquiring a color space value on a paper and prints a color patch for acquiring the second color space value on the paper, and the printing unit is the first color. After printing the color patch for acquiring the spatial value and the color patch for acquiring the second color spatial value on at least one of the plurality of sheets of the paper, the plurality of color patches for acquiring the first color spatial value are applied. It prints on the paper to be printed next to at least one of the sheets, and the color patch for acquiring the second color space value is printed next to the at least one of the plurality of sheets. A color patch generator that does not print on paper.

The invention according to claim 2 is a value obtained by reading the color patch generator according to claim 1 and the color patch for acquiring the first color space value, and the second color space value acquisition. It is an image forming apparatus including a control unit that generates color conversion profile data from a value obtained by measuring the color of a color patch for.

The invention according to claim 3 is for acquiring a first color space value which is a device-dependent color space of a color patch reader for reading a color patch, and is a device-independent color space of the color patch reader. A printing unit for printing a color patch for acquiring a color space value of 2 on a paper and printing a color patch for acquiring the second color space value on the paper is provided, and the printing unit is the first. After printing the color patch for acquiring the color space value and the color patch for acquiring the second color space value on at least one of the plurality of sheets of the paper, the color patch for acquiring the first color space value is applied. Print on the paper to be printed next to at least one of the plurality of sheets, and print the color patch for acquiring the second color space value next to the paper at least one of the plurality of sheets. It is a color patch generator that does not print on the paper to be printed.
The invention according to claim 4 is the color patch generator according to claim 3 , a value obtained by reading the color patch for acquiring the first color space value, and the second color space value acquisition. It is an image forming apparatus including a control unit that generates color conversion profile data from a value obtained by measuring the color of a color patch for .

The invention according to claim 5 is for acquiring a first color space value, which is a device-dependent color space of the image forming apparatus that reads a color patch in an image forming apparatus including a control unit, and is the image forming apparatus. The step of printing the color patch for acquiring the second color space value, which is the device-independent color space, on the paper and the step of printing the color patch for acquiring the second color space value on the paper are executed. In the program, after printing the color patch for acquiring the first color space value and the color patch for acquiring the second color space value on at least one of a plurality of sheets of the paper, the first color is printed. The color patch for acquiring the spatial value is printed on at least one of the plurality of sheets of the paper to be printed next to the paper, and the color patch for acquiring the second color spatial value is printed on at least one of the plurality of sheets. This is a program that does not print on the paper that is printed next to the paper.
The invention according to claim 6 is for acquiring a first color space value, which is a device-dependent color space of a color patch reading device that reads a color patch in an image forming device including a control unit, and is the color patch reading device. The step of printing the color patch for acquiring the second color space value, which is the device-independent color space, on the paper, and the step of printing the color patch for acquiring the second color space value on the paper are executed. After printing the color patch for acquiring the first color space value and the color patch for acquiring the second color space value on at least one of a plurality of sheets of the paper, the first color patch is used. A color patch for acquiring a color space value is printed on at least one of the plurality of sheets of the paper to be printed next to the paper, and a color patch for acquiring the second color space value is printed on at least one of the plurality of sheets. A program that does not print on the paper that is printed next to any of the above papers.

According to the invention of claim 1-6 , in order to acquire the first color space value which is the device-dependent color space, and to acquire the second color space value which is the device-independent color space. A color patch that is not and a color patch for acquiring a second color space value can be arranged on the same paper.

It is a block diagram of the image forming apparatus of an embodiment. It is explanatory drawing of the color patch of embodiment. It is explanatory drawing of the color patch of another embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<Basic principle>
The basic principle of the present embodiment is to separate the color patch for acquiring the first color space value and the color patch for acquiring the second color space value, and the color for acquiring the second color space value. The patch size of the patch is reduced, and the color patch for acquiring the second color space value is also arranged on the paper on which the color patch for acquiring the first color space value is printed, that is, the chart. Here, the first color space is a color space that depends on the image forming apparatus (device-dependent color space), and for example, RGB corresponds to it. The second color space is a color space that does not depend on the image forming apparatus (device-independent color space), and corresponds to, for example, Lab. Hereinafter, the first color space will be described as RGB, and the second color space will be described as Lab.

A color patch for acquiring RGB values is provided in an image forming device such as an in-line sensor, and is a specific patch in a specific area of paper due to implementation and technical restrictions of a reading means for acquiring colors in a device-dependent color space. Printing in size is required, resulting in printing over multiple sheets. If the color is measured using a colorimeter using the color patch over a plurality of sheets for acquiring the RGB value as it is, the color is measured over a plurality of sheets, which is troublesome.

Therefore, in the present embodiment, the patch size of the color patch for acquiring the Lab value is relative to each other by utilizing the fact that the influence of the cavity effect when acquiring the RGB value by the in-line sensor is relatively small in the color measurement by the colorimeter. By reducing the number of color patches for acquiring the Lab value and arranging them on the same paper as the color patches for acquiring the RGB values, the color patches for acquiring the RGB values and the colors for acquiring the Lab values are arranged. Even if the patches are separate, the number of color measurement steps can be significantly reduced without increasing the total number of sheets (charts).

Assuming that the number of color patches for acquiring RGB values in this embodiment is M, the number of patches is m, the number of charts of color patches for acquiring Lab values is N, and the number of patches is n.
M> N
m = n
Is.
However, M ≧ N may be set instead of M> N. The inclusion of M = N is in consideration of the fact that the arrangement of the color patch for acquiring the Lab value may be redundant.

In the following description, the cases of M = 18, N = 2, and m = n = 1584 will be illustrated, but it goes without saying that the case is not necessarily limited to this.

Further, in the present embodiment, the color patch for acquiring the RGB value and the color patch for acquiring the Lab value are arranged at different positions on the same paper (same chart), but the color for acquiring the RGB value is used on all the papers. It is not necessary to include the patch and the color patch for acquiring the Lab value. That is, it suffices that at least one of a plurality of sheets (charts) on which the color patch for acquiring the RGB value is arranged includes the color patch for acquiring the Lab value.

Further, in the present embodiment, the color patch for acquiring the RGB value and the color patch for acquiring the Lab value are arranged separately on the upper and lower sides of the same paper (chart), but are arranged separately on the left and right as necessary. It may be set arbitrarily for the position.

<Structure>
Next, the configuration of the present embodiment will be specifically described.

FIG. 1 is a configuration diagram of an image forming apparatus according to the present embodiment. The image forming apparatus 10 may be connected to the management server via a network.

The image forming apparatus 10 is a printer, a multifunction device, or the like, and includes a color conversion unit 101, a print engine 102, a color patch reading unit 103, a storage unit 104, a control unit 105, and a user interface unit 106. The colorimeter 107 may be a part of the image forming apparatus 10 or may exist separately from the image forming apparatus 10.

The image forming apparatus 10 executes a process for printing out the input print image data. The printed image data is, for example, bitmap image data or image data described in PDL (page description language). When the image forming apparatus 10 includes a scanner, the image data read by the scanner may be used as the print image data. The printed image data is converted into a raster image that can be processed by the print engine 102 by an interpreter (not shown) or other image processing unit.

The color conversion unit 101 performs color conversion on the raster image according to the profile data. The profile data is data including information indicating a correspondence relationship between the color coordinates of each lattice point in the input side color space and the color coordinates of the output side color space corresponding to the lattice points. The output side color space is the color space of the print engine 102, and is typically represented by a combination of four colors of cyan (C), magenta (M), yellow (Y), and black (K). The profile data is generated by the control unit 105 and stored in the storage unit 104. For example, profile data may be generated for each type of paper and stored in the storage unit 104, and the user may select and use data suitable for the paper to be used from a plurality of profile data. The color conversion unit 101 calculates the color coordinates of the output side color space for each pixel of the raster image when the value (color coordinates) of the pixel is used as the color coordinates of the input side color space according to the profile data.

The print engine 102 prints an image of the color conversion result output by the color conversion unit 101 on paper.

The color patch reading unit 103 reads the color patch printed by the print engine 102 under the control of the control unit 105, acquires an RGB value, and outputs the RGB value to the control unit 105. The color patch reading unit 103 is composed of an in-line sensor (ILS) or the like. The in-line sensor has almost the same configuration as a known image reading scanner, and specifically includes an imaging unit, an illumination unit, an image processing unit, and a sensor calibration unit. It is preferable that the mounting position in the image forming apparatus 10 is in the vicinity of the paper ejection portion where the color development of the printed color patch is completed, the curl of the paper is removed, and the posture is stabilized. The image processing unit is equipped with a three-color CCD, reads in real time, corrects variations, and calculates color information of a color patch.

The control unit 105 controls the entire image forming apparatus 10 according to the processing program stored in the program memory. The control unit 105 receives a print instruction from the user via the user interface unit 106, controls the color conversion unit 101, the print engine 102, and the like to print the target image of the print instruction. In addition, the control unit 105 executes a process for generating profile data. For the profile data, the print engine 102 prints a color patch that serves as a color reference, the print result is read by the color patch reader 103, and the color is measured by the colorimeter 107. The RGB values and the RGB values obtained from these measurement results are obtained. Generated based on the Lab value data group. The generated profile data is stored in the storage unit 104. The color patch is an image pattern in which color patches having different densities are arranged in a plurality of stages for each CMYK color. The color patch data is stored in the storage unit 104 as a chart pattern, and the control unit 105 reads the data according to the processing program and causes the print engine 102 to print the data.

A known algorithm can be used as a method for calculating the profile indicating the conversion from the RGB value to the Lab value. For example, it may be composed of a first step of performing a brightness conversion by a lookup table (LUT) and a second step of performing a linear conversion by a matrix calculation (for example, a 3 × 10 matrix calculation). It is calculated from a large number of color patch readings by a certain calculation algorithm. These LUTs and determinant coefficients are stored in the storage unit 104 as parameters.

The user interface unit 106 notifies the user of the state of the image forming apparatus 10 and receives an instruction input from the user. The user interface unit 106 may include, for example, a display device such as a liquid crystal touch panel and an input button such as a keypad.

Here, the chart pattern stored in the storage unit 104 is data that defines an arrangement of color patches printed by the print engine 102 in order to acquire RGB values and Lab values, but the implementation of the color patch reading unit 103. Due to the above restrictions, only half of the printing paper can be placed with color patches, and the light emitted from the light source is reflected not only by the color patch to be measured but also by the adjacent color patches, and from the adjacent color patches. The light returned to the light source is further reflected and irradiated to the color patch to be measured, so that the reflected light affected by the reflectance of the adjacent color patch is received by the image reading element. Considering this, since it is also necessary to secure the patch area, the number of color patches will be a plurality of sheets, for example, 18 sheets. In this case, in order to acquire the RGB value, it is necessary to read at the time of outputting 18 color patches, and further, the color measuring device 107 must measure the colors of these 18 color patches, which takes time in the color measuring process.

Therefore, the control unit 105 has the same combination as the color patch for acquiring the RGB value (however, its size is small) in addition to the color patch for acquiring the RGB value according to the processing program. A color patch is set, and the color patch for acquiring the Lab value is placed on the same paper as the color patch for acquiring the RGB value.

Next, the color patch of this embodiment will be described.

FIG. 2 schematically shows a color patch for acquiring RGB values and a color patch for acquiring Lab values according to this embodiment. Although the color patch is shown as an unfilled rectangular area in the figure, it is actually a patch in which the density is changed in a plurality of stages for each color of CMYK.

<Color patch for RGB value acquisition>
As described above, the color patch for acquiring the RGB value is printed over a plurality of sheets due to the technical restrictions of the mounting of the color patch reading unit (in-line sensor) 103 and the cavity effect. Specifically, if only half of one sheet of paper can be placed with patches, the area of one color patch is 2 cm x 2 cm or more, and the number of patches is 1584, the number of color patches is 18. Become. The papers (charts) on which these 18 color patches for acquiring RGB values are printed are 20-1, 20-2, 20-3, ..., 20-18 (of these, 20-1, 20 in the figure). Only -2 and 20-3 are shown). A color patch 22 for acquiring RGB values is printed on the upper half of these 18 sheets of paper 20-1, 20-2, 20-3, ..., 20-18. Of course, the pattern of the color patch 22 printed on the paper 20-1 and the pattern of the color patch 22 printed on the paper 20-2 or 20-3 are different from each other.

<Color patch for acquiring Lab value>
On the other hand, the color patch for acquiring the Lab value is not affected by the cavity effect as much as the color patch reading unit (in-line sensor) 103, so that the area of one color patch is smaller than that of the color patch 22 for acquiring the RGB value. It can be reduced to, for example, about 0.7 cm × 0.7 cm.

Therefore, the number of patches (1584) is the same as that of the color patch 22 for acquiring the RGB value, but the area of one patch is small, and the color patch 24 for acquiring the Lab value is divided into two to obtain the Lab value. The color patches 24a and 24b for acquisition are used, the color patch 24a for acquiring the Lab value is printed on the lower half of the paper 20-1 on which the color patch 22 is printed on the upper half, and the color patch 24b for acquiring the Lab value is colored. The patch 22 is printed on the lower half of the paper 20-2 printed on the upper half.

It is not necessary to print the color patch 24 for acquiring the Lab value on the other papers 20-3, 20-4, ..., 20-18, but the color patches 24a and 24b for acquiring the Lab value are appropriately printed. You may print it.

In this way, the color patch 24 for acquiring the Lab value is separated from the color patch 22 for acquiring the RGB value, and the color patch 24 for acquiring the Lab value is the same as the color patch 22 for acquiring the RGB value. By arranging on the same paper (or the same chart), the color measurement step for acquiring the Lab value can be reduced from 18 sheets to 2 sheets.

That is, when acquiring the RGB value and the Lab value by assuming that the color patch for acquiring the RGB value and the color patch for acquiring the Lab value are the same, 18 color patches are read and used to acquire the RGB value. Where it is necessary to measure the colors of 18 color patches, in this embodiment, it is sufficient to read the 18 color patches and measure the colors of only 2 color patches in order to acquire the RGB values. It will be. Moreover, in the present embodiment, even if the color patch 24 for acquiring the Lab value is separate from the color patch 22 for acquiring the RGB value, the total number of sheets (the number of patterns in the chart) remains 18. Please note.

Table 1 shows the number of patches, the number of chart patterns, the print area, and the patch size of the color patch 22 for acquiring the RGB value and the color patch 24 for acquiring the Lab value in the present embodiment.

In Table 1, the ILS reading area of the printing area means the reading range of the color patch reading unit (in-line sensor: ILS) 103, and specifically shows the upper half of the paper in FIG. Further, the large and small patch sizes are relative, and when one patch size of the color patch 22 for acquiring the RGB value is used as a reference, one patch size of the color patch 24 for acquiring the Lab value is relative. Means small.

In the present embodiment, the color patch 24 for acquiring the Lab value is divided into two to be the color patches 24a and 24b for acquiring the Lab value, and the color patch 24a for acquiring the Lab value is arranged on the paper 20-1. At the same time, the color patch 24b for acquiring the Lab value is arranged on the paper 20-2, but when there is a margin in the margin due to the size of the paper and the size of the color patch 22 for acquiring the RGB value, FIG. As shown in the above, the color patch 24 for acquiring the Lab value may be arranged only on the paper 20-1. In this case, the number of putters of the color patch 24 for acquiring the Lab value is further reduced to one.

The image forming apparatus 10 of the present embodiment is connected to a color management server via a network, the image forming apparatus 10 outputs a color patch to measure colors, transmits color measurement data to the color management server, and causes the color management server. It can also be applied to a system that periodically remotely manages the state of the image forming apparatus 10 on the side.

10 Image forming device, 22 Color patch for RGB value acquisition, 24, 24a, 24b Color patch for Lab value acquisition, 101 color conversion unit, 102 print engine, 103 color patch reader, 104 storage unit, 105 control unit, 106 User interface section, 107 Colorimeter.

Claims (6)

A color patch for acquiring a first color space value, which is a device-dependent color space of an image forming apparatus for reading a color patch, and not for acquiring a second color space value, which is a device-independent color space of the image forming apparatus. Is printed on paper, and
A printing unit for printing the color patch for acquiring the second color space value on the paper is provided.
The printing unit prints the color patch for acquiring the first color space value and the color patch for acquiring the second color space value on at least one of a plurality of sheets of the paper, and then prints the first color. A color patch for acquiring a spatial value is printed on at least one of the plurality of sheets of the paper to be printed next to the paper, and
A color patch generator that does not print the color patch for acquiring the second color space value on the paper to be printed next to at least one of the plurality of sheets. The color patch generator according to claim 1 and
Color conversion profile data is generated from the value obtained by reading the color patch for acquiring the first color space value and the value obtained by measuring the color of the color patch for acquiring the second color space value. Control unit and
An image forming apparatus comprising. It is for acquiring the first color space value which is the device-dependent color space of the color patch reader that reads the color patch, and is not for acquiring the second color space value which is the device-independent color space of the color patch reader. Print color patches on paper and
A printing unit for printing the color patch for acquiring the second color space value on the paper is provided.
The printing unit prints the color patch for acquiring the first color space value and the color patch for acquiring the second color space value on at least one of a plurality of sheets of the paper, and then prints the first color. A color patch for acquiring a spatial value is printed on at least one of the plurality of sheets of the paper to be printed next to the paper, and
A color patch generator that does not print the color patch for acquiring the second color space value on the paper to be printed next to at least one of the plurality of sheets. The color patch generator according to claim 3 and
Color conversion profile data is generated from the value obtained by reading the color patch for acquiring the first color space value and the value obtained by measuring the color of the color patch for acquiring the second color space value. Control unit and
An image forming apparatus comprising. For image forming devices equipped with a control unit
A color for acquiring a first color space value, which is a device-dependent color space of the image forming apparatus for reading a color patch, and not for acquiring a second color space value, which is a device-independent color space of the image forming apparatus. The steps to print the patch on paper and
A step of printing the color patch for acquiring the second color space value on the paper, and
Is a program that executes
After printing the color patch for acquiring the first color space value and the color patch for acquiring the second color space value on at least one of a plurality of sheets of the paper, the first color space value acquisition is performed. The color patch is printed on the paper to be printed next to the at least one of the plurality of sheets, and the color patch for acquiring the second color space value is applied to the at least one of the plurality of sheets of the paper. Do not print on the next printed paper,
program. For image forming devices equipped with a control unit
It is for acquiring the first color space value which is the device-dependent color space of the color patch reader that reads the color patch, and is not for acquiring the second color space value which is the device-independent color space of the color patch reader. Steps to print color patches on paper,
A step of printing the color patch for acquiring the second color space value on the paper, and
Is a program that executes
After printing the color patch for acquiring the first color space value and the color patch for acquiring the second color space value on at least one of a plurality of sheets of the paper, the first color space value acquisition is performed. The color patch is printed on the paper to be printed next to the at least one of the plurality of sheets, and the color patch for acquiring the second color space value is applied to the at least one of the plurality of sheets of the paper. Do not print on the next printed paper,
program.

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