JP2000333027A - Printer, its method and medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reflect other information than a color reproduction characteristic measured by a printer itself onto calibration of color reproduction. SOLUTION: A color transformation section 21 transforms document data (RGB signal) into print section input data (cmy signal) on the basis of a LUT from a transformation condition analysis section 25 in the case of usual print and outputs the transformed data to a print section 17. A colorimetry section 18 measures colors of a color calibration color chart to provide an output of colorimetric values (X, Y, Z) to a characteristic analysis section 23. The characteristic analysis section 23 generates print characteristic data including the LUT that transforms the cmy signal into relative colorimetric values (X', Y', Z') based on the measured values (X, Y, Z) from the colorimetry, section 18. A transformation condition analysis section 25 generates the LUT to transform the RGB signal into the cmy signal on the basis of the print characteristic data and the monitor characteristic data recorded in a color reproduction characteristic recording section 24 and gives the LUT to a color transformation section 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus, a printing method, and a medium, and more particularly, to a printing apparatus and method for measuring the color of a printed color chart and correcting the color reproduction based on the color measurement result. , As well as media.

[0002]

2. Description of the Related Art Conventionally, as a method of calibrating colors printed by a color printer (calibrating color reproduction), a color chart composed of predetermined color patches is printed, and the density and reflection of each color patch on the color chart are measured. The ratio, the color value, the spectral reflectance, and the like are measured using a predetermined colorimeter, and a correction process is performed to subtract the color reproduction characteristics. This method has a problem that a predetermined colorimetric device is required and that a user must adjust data referred to by a color printer or its control device based on the colorimetric result. Therefore, the applicant of the present application has disclosed in Japanese Patent Application Laid-Open No. Hei 7-17115 (hereinafter referred to as the prior application) a colorimetric means for measuring the color chart printed by the user and a color to be printed based on the colorimetric result. There has been proposed a color printer including a color correction unit for performing correction.

[0003]

However, in the color printer of the prior application, information other than the color reproduction characteristics measured by the colorimetric means (for example, the color reproduction characteristics measured in the past,
There is a problem that the color reproducibility characteristics measured using other colorimetric devices and the color reproduction characteristics of devices (monitors and the like) other than the color printer that reproduces the same information cannot be reflected in the correction of the color to be printed. Was.

[0004] The present invention has been made in view of such circumstances, and provides a printing apparatus capable of reflecting information other than the color reproduction characteristics measured by the user in the calibration of color reproduction.

[0005]

According to a first aspect of the present invention, there is provided a printing apparatus for converting an input image signal into a printing signal based on a look-up table, and converting a color image corresponding to the printing signal. Printing means for printing, and color measurement means for measuring the color chart for calibration printed by the printing means,
Generating means for generating first characteristic data for converting the print signal into color space coordinates based on the colorimetric result of the colorimetric means; and generating the first characteristic data generated by the generating means; Updating means for updating the look-up table based on the second characteristic data for converting to the color space coordinates.

According to a third aspect of the present invention, there is provided a printing method comprising: converting an input image signal into a printing signal based on a look-up table; printing a color image corresponding to the printing signal; A color measurement step of measuring the color chart for calibration printed in the printing step,
A generating step of generating first characteristic data for converting the printing signal into color space coordinates based on the colorimetric result of the colorimetric step; and a first characteristic data generated in the generating step; Updating the look-up table based on the second characteristic data for converting to the color space coordinates.

According to a fourth aspect of the present invention, there is provided a program for a medium, comprising: a converting step of converting an input image signal into a printing signal based on a look-up table; and a printing step of printing a color image corresponding to the printing signal. Generating a first characteristic data for converting a printing signal into color space coordinates based on a colorimetric result of the colorimetric step of measuring the color chart for calibration printed in the printing step; A generation step; and an update step of updating a look-up table based on the first characteristic data generated in the generation step and second characteristic data for converting an image signal into color space coordinates. And

In the printing apparatus according to the first aspect, the printing method according to the third aspect, and the medium program according to the fourth aspect, the input image signal is converted into a printing signal based on a look-up table. The image is converted and a color image corresponding to the printing signal is printed. Further, the printed calibration color chart is measured in color, and first characteristic data for converting the printing signal into color space coordinates is generated based on the color measurement result, and the generated first characteristic data is generated. Data and
The look-up table is updated based on the second characteristic data for converting the image signal into the color space coordinates.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A configuration example of a color printer 1 to which the present invention is applied will be described with reference to FIG. The color printer 1 converts input document data into print data based on a predetermined conversion table in accordance with a print command from a personal computer (PC) 2, supplies the print data to a print unit 17, and measures the print data. A control unit 11 for correcting the conversion table based on the color measurement result supplied from the color unit 18;
A printing unit 17 that prints an image corresponding to the printing data supplied from the control unit 11 on a printing paper 22 (FIG. 2), and measures a color chart on a color calibration color chart printed by the printing unit 17 The colorimetric section 18 supplies a colorimetric value (X, Y, Z) to the control section 11 as a colorimetric result.

The control unit 11 includes a CPU 12 for executing processing described below in accordance with a predetermined program recorded in a RAM 13 and a ROM 14, a RAM 13 and a ROM 14 for storing predetermined programs and data, and a personal computer 2
Interfaces 15 for receiving document data input from a computer are connected to each other via a bus 16. The RAM 13 is also used as a buffer for temporarily storing document data and a work area for the CPU 12.

FIG. 2 shows that the CPU 12 of the control unit 11
2 is a functional block diagram when processing is performed according to a predetermined program recorded in a ROM 14.

The color conversion unit 21 performs a normal printing operation.
Document data (data in which each pixel is represented by three components (Red (Red), Green (Green), Blue (Blue))) from the personal computer 2 is supplied from the conversion condition analysis unit 25.
Based on a look-up table (hereinafter referred to as LUT) that converts an RGB signal into a cmy signal, the printing unit input data (each pixel has three components (cyan (blue), magenta (red), yello
w (yellow)) and outputs it to the printing unit 17.

Further, the color conversion section 21 outputs the stored printing section input data of the color calibration color chart to the printing section 17 at the time of color calibration. The printing unit 17 is a printing unit input data (c, m, y) input from the color conversion unit 21.
Images corresponding to the three colors of ink (cyan (blue), magent
a (red) and yellow (yellow))
Print on

The colorimetric section 18 is arranged at a predetermined distance from the printing section 17 in the paper feeding direction, and each printed c,
A photoelectric conversion element (CCD) that detects each of the m and y components and converts it into an electric signal;
A built-in 0K illumination and a conversion unit (both not shown) convert a predetermined color chart on a color calibration color chart printed by the printing unit 17 into an electric signal by a photoelectric conversion element. The converted electrical signal is converted by the converter into CIE (Commission International
ale de L'Eclairage) Color space coordinates (X,
(Y, Z) and outputs it to the characteristic analysis unit 23 as a colorimetric value (X, Y, Z). The color chart for color calibration, which is set to t gradation between 0% to 100% for each component of the CMY signals were placed t ³ kinds of color chips is realized by the combination vertically and horizontally regular intervals It is.

The characteristic analyzing section 23 prints the printing characteristics of the printing section 17 based on the colorimetric values (X, Y, Z) of all the color charts on the color calibration color chart input from the color measuring section 18. Data (LUT for converting cmy signal to relative colorimetric value (X'Y'Z '))
Is generated and output to the color reproduction characteristic recording unit 24. The color reproduction characteristic recording unit 24 stores the print characteristic data input from the characteristic analysis unit 23 and the monitor characteristic data (RGB signals are input from outside the printer 1 by a predetermined method). LUT for converting into a colorimetric value (X'Y'Z ') is recorded. The conversion condition analysis unit 25 generates an LUT for converting an RGB signal into a cmy signal based on print characteristic data and monitor characteristic data recorded in the color reproduction characteristic recording unit 24, and supplies the LUT to the color conversion unit 21.

Next, the operation will be described. In the normal printing process, the color conversion unit 21 converts the document data (R, G, B) supplied from the personal computer 2 into the printing unit input data (c) based on the LUT supplied from the conversion condition analysis unit 25. , M, y) and output to the printing unit 17. In the printing unit 17, an image corresponding to the printing unit input data (c, m, y) input from the color conversion unit 21 is printed on the printing paper 22 using three color inks.

The color proofing process will be described with reference to the flowchart of FIG. This color proofing process is performed by a predetermined method when the user feels the need to change the connected personal computer 2 or monitor, or changes the ink or printing paper used for printing, for example. It is started when the execution of the processing is instructed.

In step S1, the color conversion unit 21
The printing unit 17 supplies the printing unit input data of one color chart constituting the stored color calibration color chart to the printing unit 17. The printing unit 17 prints a color chart corresponding to the printing unit input data input from the color conversion unit 21 on the printing paper 22.

In step S2, the colorimetric section 18 measures the color of the color chart on the color proofing color chart printed in step S1, and sets the colorimetric value (X, Y, Z) as the characteristic analysis section 2.
Output to 3.

In step S3, the colorimetric section 18 determines whether or not all the color charts constituting the color proof color chart have been measured. If it is determined that all the color patches have not been measured, the process returns to step S1, and the subsequent processes are repeated. Thereafter, if it is determined that all the color patches have been measured, the process proceeds to step S4.

In step S4, the characteristic analyzer 23
The color chart colorimetric values the value of each component of cmy signal is 0 (X, Y, Z) as a reference value Y ₁₀₀ the value of the Y component of colorimetric values input from color measurement section 18 ( X, Y, Z) are converted into relative colorimetric values (X ′, Y ′, Z ′). _{However, X '= Z / Y 100} Y' = Y / Y 100 Z '= a Z / Y _100.

Further, the characteristic analyzer 23 calculates the relative colorimetric values (X ′, X ′) corresponding to the cmy signals of all (t ³ ) color chips.
Y ′, Z ′), interpolating the cmy signal which is a discrete value, and converting print characteristic data including an LUT for converting the cmy signal into relative colorimetric values (X ′, Y ′, Z ′). It is generated and output to the color reproduction characteristic data recording unit 24.

In step S5, the conversion condition analysis unit 2
Reference numeral 5 newly generates an LUT for converting an RGB signal into a cmy signal based on the monitor characteristic data recorded in the color reproduction characteristic recording unit 24 and the print characteristic data generated by the characteristic analysis unit 23. That is, the conversion condition analysis unit 25 performs an inverse conversion of the LUT for converting the cmy signal included in the print characteristic data into the relative colorimetric values (X ′, Y ′, Z ′).
(LUT for converting relative colorimetric values (X ′, Y ′, Z ′) into cmy signals) and converting the RGB signals included in the monitor characteristic data into relative colorimetric values (X ′, Y ′, Z). LUT to convert to ')
LU that converts RGB signals to cmy signals by combining
Generate T. Further, the conversion condition analysis unit 25 supplies the generated LUT to the color conversion unit 21. The color conversion unit 21 updates the stored LUT using the LUT from the conversion condition analysis unit 25.

By appropriately executing the above-described color proofing processing, the color of the printed matter output by the color printer 1 can be adjusted.
It is possible to match the color with the image displayed on the monitor.

The above-described embodiment may be modified as described below. That is, in the present embodiment, the document data from the personal computer is an RGB signal, and the printing unit input data supplied to the printing unit 17 is the cmy signal. However, these correspond to the standard color space. Any other type of signal may be used as long as it can be described.

The object to be printed by the printing unit 17 does not have to be paper.

The color conversion unit 21 uses the LUT to perform RGB
Although the signal is converted to the cmy signal, the signal may be converted using a predetermined arithmetic expression.

Further, the values output by the colorimetric section 18 may be other standard defined values instead of the colorimetric values (X, Y, Z). For example, the colorimetric unit 18 outputs a density value,
The characteristic analysis unit 23 rewrites only the gradation characteristics describing the relationship between the density value and the cmy signal in the existing print characteristic data stored in the color reproduction characteristic data recording unit 24, and the conversion condition analysis unit 25 Only the gradation characteristics of the color conversion unit 21 may be managed.

The color space that the characteristic analysis unit 23 associates with the CMY signal to describe the print characteristics is not an XYZ color space,
Other standard color spaces may be used. However, in this case, it is necessary that the colorimetric values output by the colorimetric unit 18 can be converted to the standard color space.

The characteristic analysis unit 23 may create a parameter of a mathematical expression indicating a gradation characteristic of the cmy signal or a numerical value table. In this case, it is desirable that the LUT describes the correspondence between the cmy signal and the XYZ signal linearized according to the gradation characteristics.

In the characteristic analyzing unit 23, cmy is used as the printing characteristic.
In order to describe the relationship between the signal and the XYZ signal, a parameter used in an expression capable of expressing printing characteristics may be specified and described in the printing characteristics data.

The method of relativizing the colorimetric values (X, Y, Z) may be another method. However, the relative value needs to match the value describing the monitor characteristic data.

In the conversion condition analysis means, the RGB signals are converted to X'Y '
A conversion means for converting to a Z 'signal and a means for directly receiving the print characteristic data generated by the characteristic analysis unit 23 are provided, and only the color conversion conditions need to be updated without leaving the past print characteristic data. In this case, it is not always necessary to use the color reproduction characteristic data recording unit 24.

In the conversion condition analysis means, the standard color space that mediates between the document data and the print unit output data is a color space other than XYZ if the color space has a one-to-one correspondence with monitor characteristic data and print characteristic data. May be used.

The conversion condition analysis means extracts predetermined data from the monitor characteristic data and the print characteristic data, executes color adaptation conversion and color gamut compression processing using the extracted data, and determines the color reproduced by the monitor and the color printer. The color to be reproduced may be made closer in appearance.

In the conversion condition analysis means, existing print characteristic data may be used for generating color conversion conditions.

When printing document data, the cmy signal converted using the color conversion conditions generated by the conversion condition analysis unit 25 is converted into print characteristic data and monitor characteristic data recorded in the color reproduction characteristic data recording unit 24. Alternatively, the color that is expected to be printed by the color printer 1 may be displayed on a monitor by performing an inverse conversion to an RGB signal.

The series of processes described above can be executed by hardware, but can also be executed by software. When a series of processing is executed by software, a program constituting the software is executed by a computer (corresponding to the control unit 11) incorporated in the color printer 1 as dedicated hardware or various programs. By installing the software, the software is installed in a general-purpose personal computer (corresponding to the personal computer 2 in FIG. 1) that can execute various functions.

Next, with reference to FIG. 4, a description will be given of a medium used to install a program for executing the above-described series of processing in a computer and make the computer executable.

As shown in FIG. 4A, the program is stored in a hard disk 102 or a semiconductor memory 103 (RAM in FIG. 1) as a recording medium built in the computer 101.
13 and the ROM 14) in advance.

Alternatively, as shown in FIG. 4B, the program is stored in a floppy disk 111, a CD-ROM (Compa
ct Disc-Read Only Memory) 112, MO (Magneto Opti
cal) Disc 113, DVD (Digital Versatile Disc) 1
14, temporarily or permanently stored in a recording medium such as a magnetic disk 115 or a semiconductor memory 116, and can be provided as package software.

Further, as shown in FIG. 4C, the program is transmitted from the download site 121 to the satellite 12 by radio.
2 or via a network 131 such as a local area network or the Internet by wire or wirelessly to the computer 123, and stored in a built-in hard disk or the like in the personal computer 123.

The medium in the present specification means a broad concept including all these media.

In this specification, the step of describing a program provided by a medium is not limited to processing performed in chronological order according to the described order, but is not necessarily performed in chronological order. This also includes processes executed individually.

In the present specification, the system is
It represents the entire device composed of a plurality of devices.

[0046]

As described above, according to the printing apparatus of the first aspect, the printing method of the third aspect, and the medium program of the fourth aspect, the printed calibration color chart is measured. Coloring, generating first characteristic data for converting a printing signal into color space coordinates based on the colorimetric result, and converting the generated first characteristic data and the input image signal into a color space. Since the look-up table is updated based on the second characteristic data for converting into coordinates, it is possible to reflect information other than the color reproduction characteristics measured by the self in the color reproduction calibration. .

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration example of a color printer 1 to which the present invention has been applied.

FIG. 2 is a diagram showing functional blocks of a control unit 11 of FIG.

FIG. 3 is a flowchart illustrating a color proofing process of the color printer.

FIG. 4 shows a program installed on a computer;
FIG. 7 is a diagram for describing a medium used to make the state executable.

[Explanation of symbols]

Reference Signs List 1 color printer, 11 control unit, 17 printing unit, 18 color measurement unit, 21 color conversion unit, 22 printing paper, 23 characteristic analysis unit, 24 color reproduction characteristic data recording unit, 25 conversion condition analysis unit

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 2C061 AR01 BB10 BB11 KK14 KK18 KK28 KK32 2C087 BA07 BA12 BD36 BD46 CB04 DA06 5B057 AA11 BA28 CA01 CA08 CA12 CA16 CB01 CB02 CB08 CB16 CC01 CE17 CE18 CH07 DC25 5C037 MM33 PP37 PP42 PP43 PQ23 TT02 TT06 5C079 HB01 HB02 HB05 HB12 LA02 LB02 MA05 MA10 NA03 PA02 PA03

Claims (4)

[Claims] 1. A printing device for printing a color image, comprising: a conversion unit for converting an input image signal into a printing signal based on a lookup table; and a printing unit for printing a color image corresponding to the printing signal. A colorimetric unit for measuring the color chart for calibration printed by the printing unit; a first characteristic for converting the printing signal into color space coordinates based on a colorimetric result of the colorimetric unit. Generating means for generating data; updating the lookup table based on the first characteristic data generated by the generating means and second characteristic data for converting the image signal into the color space coordinates. A printing device comprising: 2. The printing apparatus according to claim 1, wherein the image signal is an RGB signal, and the printing signal is a cmy signal. 3. A printing method of a printing apparatus for printing a color image, comprising: a conversion step of converting an input image signal into a printing signal based on a look-up table; and printing a color image corresponding to the printing signal. A printing step, a color measurement step of measuring the color chart for calibration printed in the printing step, and a second step of converting the printing signal into color space coordinates based on the color measurement result of the color measurement step. A generating step of generating the first characteristic data; the first characteristic data generated in the generating step;
Updating the look-up table based on second characteristic data for converting the image signal into the color space coordinates. 4. A printing program for printing a color image, comprising: a conversion step of converting an input image signal into a printing signal based on a look-up table; A printing step of printing, a color measurement step of measuring the color chart for calibration printed in the printing step, and a step of converting the printing signal into color space coordinates based on the color measurement result of the color measurement step. A generating step of generating first characteristic data; the first characteristic data generated in the generating step;
An update step of updating the look-up table based on second characteristic data for converting the image signal into the color space coordinates, and causing the computer to execute a program.