JP3421865B2 - Color printer device and control method therefor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color printer apparatus for performing color printing according to input image data and a control method thereof.

[0002]

2. Description of the Related Art Conventionally, various types of printers such as an inkjet jet system and a thermal system have been put into practical use.

For example, in a thermal printer device,
By driving the thermal head in accordance with the input image data, the image is thermally transferred via the ink clink and printing is performed. In the case of a color printer device, a color image is printed by using ink limbons of basic colors such as yellow, cyan and magenta.

Conventionally, when the result of actual printout is different from the desired result, color matching is performed by trial and error or intuition by subjective evaluation of a person having a certain degree of specialized knowledge. In addition, it was also performed to measure the color of the printed out result by a colorimeter and objectively evaluate the color difference and the like based on the colorimetric data.

[0005]

By the way, the color reproduction in a color printer is very susceptible to the characteristics peculiar to the printer, the light source when observing the printer, and various other conditions. Since changes in reproduced color due to replacement or paper replacement are common among these cases, simpler correction processing is required.

However, conventionally, when the result of actual printing is different from the desired result, color matching is performed by trial and error or intuition based on subjective evaluation of a person having some specialized knowledge. Since it was vague and time-consuming, work efficiency deteriorated, and the number of people who checked the operability was limited. In particular, since the influence of ink or the like on the color changes each time a new replacement is made, it is difficult to cope with such a delicate change by such a complicated process, and the efficiency is extremely poor.

Further, even in the objective evaluation, the work is made more complicated because the colorimeter for evaluating the color difference and the processing system are separate from the printer device.

Therefore, the present invention has been proposed in view of the above situation, and an object of the present invention is to replace a color material or a paper even by a person who does not have specialized knowledge. It is an object of the present invention to provide a color printer device capable of printing a test pattern of a reference color in a test mode and a control method thereof so that a subtle change in reproduced color can be easily discriminated.

Another object of the present invention is to provide a color printer apparatus and a control method therefor capable of easily obtaining a print output of a target color tone even by a person having no specialized knowledge. .

[0010]

In order to solve the above-mentioned problems, the present invention relates to a color printer apparatus for performing color printing according to input image data by a color printing means, and stores a plurality of reference color test pattern data. The test pattern data storage means, the colorimetric condition storage means storing a plurality of colorimetric conditions, and the predetermined test pattern selected from the plurality of test patterns stored in the test pattern data storage means, and the colorimetric condition storage Selecting means for selecting a predetermined colorimetric condition from a plurality of colorimetric conditions stored in the means, and the test pattern selected by the selecting means in the test mode is read from the storage means and supplied to the color printing means, The test pattern is printed by printing the test pattern according to the colorimetric condition selected by the selecting means. Color printer apparatus, characterized in that it comprises a control means for controlling the color measurement.

Further, according to the control method of the color printer device of the present invention, the step of selecting a predetermined test pattern from the test pattern data storage means storing a plurality of reference color test pattern data and a plurality of colorimetric conditions are stored. From the selected colorimetric condition storage means, a step of selecting a predetermined colorimetric condition, a step of supplying the selected predetermined test pattern to a color printing means and printing, and a step of printing according to the selected colorimetric condition. And measuring the color of the test pattern.

[0012]

In the color printer device according to the present invention, a predetermined test pattern is selected by the selection means from the plurality of test patterns stored in the test pattern data storage means, and a plurality of color measurement condition storage means are stored. A predetermined colorimetric condition is selected from the colorimetric condition by the selecting unit, and the test pattern selected by the selecting unit in the test mode is read from the storage unit and supplied to the color printing unit to print the test pattern. The control unit controls the color measurement of the printed test pattern according to the color measurement condition selected by the selection unit.

Further, in the control method of the color printer apparatus according to the present invention, a predetermined test pattern is selected from the test pattern data storage means which stores a plurality of reference color test pattern data, and a plurality of colorimetric conditions are stored. A predetermined color measurement condition is selected from the color condition storage means, the selected predetermined test pattern is supplied to the color printing means and printed, and the color measurement of the printed test pattern is performed according to the selected color measurement condition. I do.

[0014]

Embodiments of the present invention will now be described in detail with reference to the drawings.

A color printer device according to the present invention is constructed, for example, as shown in FIG.

In the embodiment shown in FIG. 1, the thermal head 4 is driven by the thermal head driver 3 in accordance with the input image data input to the buffer memory 2 via the input terminal 1, whereby yellow, cyan, and The present invention is applied to a thermal type color printer device that thermally transfers an image through an ink clymbone 5 of a basic color such as magenta to print a color image on a sheet 6.

The color printer device of this embodiment reads the test pattern data of the reference color from the image memory 7 storing the test pattern data of the reference color and the image memory 7 in the test mode and stores the test pattern data in the buffer memory 2. A memory control unit 8 that performs supply control is provided.

The memory control unit 8 includes a color correction processing unit 15
Under the control of the central processing unit (CPU) 16, the test pattern data of the reference color is read from the image memory 7 and supplied to the buffer memory 7 in the test mode. As a result, in the test mode, the reference pattern test pattern data read from the image memory 7 is supplied to the thermal head driver 3 via the buffer memory 7. Then, the thermal head driver 3 drives the thermal head 4 in accordance with the reference pattern test pattern data to print the reference color test pattern on the paper 6.

As described above, in the color printer apparatus of this embodiment, the test pattern of the reference color can be printed on the paper 6 in the test mode based on the test pattern data of the reference color from the image memory 7. Even a person having no specialized knowledge can easily discriminate a subtle change in reproduced color due to exchange of color material or exchange of paper based on the test pattern of the reference color.

The test pattern is mainly composed of parallel patches represented by gradations of several colors or more in order to check the color characteristic peculiar to the printer device at each occasion. By measuring this color, it is possible to clarify the appearance of gradation for each color material, and it can be used as a characteristic reference in the color correction processing process described later.

Here, the image data is stored in the image memory 7.
Based on the test pattern data of the standard color
As a standard color test pattern to be printed on paper 6 when
Is, for example, as shown schematically in FIG.
(C), magenta (M), yellow (Y) single color in
Test pattern P showing gradation due to black_C, P
_M, P_Y, Two colors (C + M), (C + Y), (M + Y)
Test pattern P showing gradation with ink
_{C + M}, P_{C + Y}, P_{M + Y}, Three-color (C + M + Y) ink
Test pattern P showing gradation_{C + M + Y}Or
Representatives located at evenly spaced locations in a uniform color space
Test pattern P indicating color_RPAre adopted.

The paper 6 is transferred by the transfer roller 9 and discharged from a discharge port (not shown).

Further, the color printer apparatus of this embodiment includes a color measuring section 10 for measuring the color of the reference color test pattern printed on the paper 6 transferred by the transfer roller 9 in the test mode. This color measurement unit 10
And a color correction processing unit 15 that performs color correction based on the color measurement data according to.

The colorimetric section 10 illuminates the test pattern on the paper 6 with the colorimetric light source 11, and the reflected light by the test pattern is received by the CCD line sensor 13 via the spectroscopic element 12. Color measurement is performed and the color measurement signal obtained by the CCD line sensor 13 is A /
It is digitized by the D converter 14 and supplied to the central processing unit 16 of the color correction processing unit 15.

Here, as the spectroscopic element 12 of the colorimetric section 10, for example, as shown in FIG. 3, a film thickness t is gradually increased from one end side to the other end side on a transmission layer 12A such as glass. variable wavelength selective spectral filter obtained by forming a multiple thin film layers 12B of ₁ ~t ₂ is used. As shown in FIG. 4, a striped filter 20 of three primary colors is used instead of the spectroscopic element 10, and three primary color components R, G, of the reflected light of the test pattern of the reference color printed on the paper 6 are used.
Color measurement may be performed by detecting B with the CCD line sensor 13.

The color correction processing section 15 includes the central processing section 16 and a digital signal processor (DS).
P) 17 and calculates color correction data based on the colorimetric data supplied from the CCD line sensor 13 via the A / D converter 14, and the buffer memory 2
The input image data supplied to the thermal head driver 3 is subjected to color correction processing based on the color correction coefficient, and the color-corrected image data is supplied to the thermal head driver 3 via the buffer memory 2. ing.

As a result, in the color printer apparatus of this embodiment, the test pattern of the reference color is printed on the paper 6 in the test mode, and based on the colorimetric data obtained by the colorimetric section 10 for this test pattern. By calculating the color correction coefficient in the color correction processing unit 15, the color correction processing unit 15 performs color correction processing on the input image data based on the color correction coefficient, as shown in the flowchart of FIG. Then, color printing is performed using the image data that has been subjected to color correction processing.

Here, the color correction processing in the color printer apparatus of this embodiment is performed in the procedure as shown in FIG. 6, for example.

That is, in the process of obtaining the color correction coefficient, as shown in the flow chart of FIG. 6, first, in process 1, a reference color serving as a guideline of printer characteristics is selected from the test pattern data stored in the database. In the next process 2, the colorimetric conditions such as the light source and the visual field are selected from the colorimetric condition data previously stored in the database. Then, in the next process 3, the test pattern of the reference color is printed. Furthermore, in the next process 4,
Measure the color of the printed reference color test pattern. In the next process 5, modeling is performed from colorimetric data. Then, in the next process 6, coefficients for color correction processing are obtained as a result of the modeling in the process 5.

The test pattern of the reference color can be newly created according to the purpose, but as in this embodiment, some predetermined pattern data P _C stored in the image memory 7 in advance are stored. , P _M , P _Y , P _{C + M} , P
_By selecting from _{C + Y} , P _{M + Y} , P _{C + M + Y} , and P _PR , it is possible to save the trouble of creating the test pattern of the reference color and improve the operation efficiency.

As for the colorimetric conditions, the operation efficiency can be improved by preliminarily creating a database of the conditions such as the light source and the visual field similarly to the test pattern. Generally, the color value does not mean a value unique to itself, but a value determined by including the influence of observation conditions such as a light source. Therefore, these are indispensable conditions for colorimetry, and by setting these, it is possible to measure a strict colorimetric value under desired conditions.

In the above modeling, the input parameters (X, Y, Z and R, G, B) of the actual image data given as electric signals are calculated by performing the inverse calculation from the colorimetric values.
And printing parameters corresponding to the density of the color material used in the printer (digital count C, M, Y)
Find each conversion coefficient between and. Then, the color correction processing for the actual image is the algorithm derived from this modeling, which is calculated along the flow from the original input side to the printer side.

Here, a specific processing procedure of the above-mentioned color correction is shown in the flowchart of FIG.

In the flowchart of FIG. 7, processes (3) to (6) are modeling processes,
Process (7) to process (12) are color correction processes.

Process (1) is a process of outputting a test pattern, and dC, dM, and dY represent input signals corresponding to gradations at equal intervals in each of the three primary colors. Further, the process (2) is a process for measuring the color of the test pattern, and C, M, and Y represent measured density values obtained by measuring the output results of the above dc, dm, and dy.

Then, in the process (3), the above dC, d
M, dY is compared with C, M, Y, and the relational expression is represented by a polynomial, a look-up table (LUT), or the like.

This process (3) is a process for obtaining an equation for converting the color value processed by the real number calculation into a digital count that can be input by the computer. For example, as shown in FIG. 8, a value normalized by dividing each digital count dx by the total value (256 gradations in case of 8 bits) and a measurement result density value (colorimetric value) of an actual test pattern. Find the relationship with a high-order polynomial.

In the next process (4), the gap between the actually measured concentration value and the calculated ideal value is corrected.

Here, the color material is not spectrally dispersed in an ideal state for any of the two primary colors, but has extra absorption (illegal absorption) even in other color regions. Therefore, it is necessary to reconvert the ideal calculated value into the density value when the color material level is actually dropped.

Therefore, in this process (4), the parameters of the transformation matrix M ₁ shown in Equation ₁ are obtained by, for example, the least square method. Note that the LUT can be created at this stage.

[0041]

[Equation 1]

The following process (5) is a density-to-reflectance conversion process. In this process (5), Dx = −log ₁₀ (x / 100) x = 100 · 10 ^−DX And reflectivity of R, G, B
To the density values Dr, Dg, Db corresponding to the absorption of the light.

The next process (6) is the RG used for colorimetry.
This is the process of matching the B filter characteristics to the input RGB. However, since the RGB characteristics of the input are not constant, conversion is performed here for CIE / XYZ (CIE: International Commission on Illumination) so that the same output result can be obtained for the input. This relational expression is predetermined based on the filter characteristics and the like.

Then, in the process (7) to process (12) for performing color correction processing on the image data actually input, first, in the process (7), X, Y, Z and R, G, B are formed. Once entered, each of the modeling processes described above
The relational expressions obtained in (3) to (6) multiply the coefficients inversely. And finally, the digital counts dC, dM,
When converted to dY, it is sent to the printer.

By providing such a processing function in advance in the processing section, it is possible to save troublesome work and efficiently perform color reproduction.

In the color printer device of this embodiment, the color measuring unit 10 and the color correction processing unit 15 may be connected as an external device.

[0047]

As described above, according to the present invention, it is possible to obtain a predetermined value in the test mode from the storage means that stores a plurality of reference color test pattern data and the colorimetric condition storage means that stores a plurality of colorimetric conditions. By reading the test pattern data and supplying it to the color printing means, the test pattern of the reference color can be printed, and the color measurement of the printed test pattern can be controlled according to the predetermined selected color measurement condition. Even a person having no specialized knowledge can easily determine a subtle change in the reproduced color due to the exchange of the color material or the paper, based on the test pattern of the reference color.

Further, according to the present invention, the colorimetry of the test pattern of the reference color printed by the color printing means is performed by the colorimetry means, and the color correction means performs printing by the color correction means based on the colorimetry data. Since the color correction of the color is performed, it is possible to cope with a subtle color change, and even a person having specialized knowledge can easily obtain a print output of a target color tone.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a color printer device according to the present invention.

FIG. 2 is a diagram schematically illustrating an example of a reference color test pattern printed by the color printer device.

FIG. 3 is a perspective view showing a specific structural example of a spectroscopic element of a color measurement unit in the color printer device.

FIG. 4 is a perspective view showing a modified example in which a stripe filter of three primary colors is used instead of the spectral element of the color measurement unit.

FIG. 5 is a flowchart showing a process of processing image data in the color printer device.

FIG. 6 is a flowchart showing a process of calculating a color correction coefficient in the color printer device.

FIG. 7 is a flowchart showing a process of color correction calculation in the color printer device.

FIG. 8 is a characteristic diagram showing an example of a relationship between a test pattern output and an actually measured density value obtained by colorimetrically measuring an output result in the color printer device.

[Explanation of symbols]

1 ... Input terminal 2 ... Buffer memory 3 ... Thermal head driver 4 ... Thermal head 5 ... Ink ribbon 6 ... Paper 7 ... Image memory 8 ... Memory control unit 10 ... Color measurement section 11 ... Light source 12 ... Spectroscopic element 13 ... CCD line sensor 14 ... A / D converter 15 ... Color correction processing unit 16 ... Central processing unit 17 ... Digital signal processor

Continuation of front page (56) Reference JP-A-4-329066 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B41J 29/46

Claims (3)

(57) [Claims] 1. A color printer apparatus for performing color printing according to input image data by a color printing unit, a test pattern data storage unit storing a plurality of reference color test pattern data, and a color measurement unit storing a plurality of color measurement conditions. A predetermined test pattern is selected from the condition storage means and the plurality of test patterns stored in the test pattern data storage means, and the predetermined color measurement condition is selected from the plurality of color measurement conditions stored in the color measurement condition storage means. Selection means to be selected, and the test pattern selected by the selection means in the test mode is read from the storage means and supplied to the color printing means, the test pattern is printed, and the color measurement condition selected by the selection means is selected. And a control means for controlling the color measurement of the printed test pattern according to Color printer. 2. A color measuring unit that measures the color of the test pattern printed by the color printing unit, and a color correction of the print color by the color printing unit based on color measurement data by the color measuring unit. 2. The color printer device according to claim 1, further comprising color correction means. 3. A step of selecting a predetermined test pattern from a test pattern data storage means storing a plurality of reference color test pattern data, and a predetermined color measurement from a color measurement condition storage means storing a plurality of color measurement conditions. The method further includes a step of selecting a condition, a step of supplying the selected predetermined test pattern to a color printing means to print it, and a step of measuring the color of the printed test pattern according to the selected colorimetric condition. A method for controlling a color printer device, comprising: