Color separation into a plurality of ink components including primary color ink and spot color ink

a color separation and ink technology, applied in the field of color printing technique, can solve the problem that no feature has been devised for color separation

Inactive Publication Date: 2009-07-23
SEIKO EPSON CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0010]According to this method, ink quantity of the spot color ink is adjusted so as to be reduced at a rate of change greater than the rate of change of the lightness parameter, whereby standing out of the spot color ink in lighter areas can be reduced, and graininess in the image improved.
[0012]According to this method, in bright image areas, the ink quantity of spot color ink is determined in such a way that the usage rate of spot color ink in areas of hue relatively close to the spot color ink is smaller than the usage rate of spot color ink in areas of hue relatively close to the chromatic primary color ink. Accordingly, in areas of hue relatively close to the spot color ink, the usage rate of spot color ink is lower, whereby standing out of the spot color ink in lighter areas can be reduced, and graininess in the image improved. In areas of hue relatively close to the chromatic primary color ink, the usage rate of spot color ink is higher, and ink quantities of the plurality of chromatic primary color inks are smaller, providing savings in the amounts of ink used.

Problems solved by technology

However, to date, in instances where use of such chromatic primary color inks and spot color inks is possible, no feature has been devised whereby color separation may be performed in consideration of image graininess caused by spot color ink dots, or in consideration of graininess and ink savings.

Method used

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  • Color separation into a plurality of ink components including primary color ink and spot color ink
  • Color separation into a plurality of ink components including primary color ink and spot color ink
  • Color separation into a plurality of ink components including primary color ink and spot color ink

Examples

Experimental program
Comparison scheme
Effect test

embodiment 1

C. Embodiment 1

C1: Example 1 of Color Separation Process in Embodiment 1

[0091]FIG. 8 is a flowchart depicting the color separation process processing routine in Example 1. In this color separation process, a process to convert from a primary color system to a reproduction color system is executed. In Step S500 in FIG. 8, an ink set composed of the chromatic primary color inks C, M, Y and the spot color inks R, V as useable inks is established.

[0092]In Step S510, a provisional color separation ink quantity set I(Cp, Mp, Yp, Rp, Vp) for reproducing on a print medium a reproduction color corresponding to an input color I(Ci, Mi, Yi) is calculated. In Example 1, it is assumed that input color I(Ci, Mi, Yi) matches a reproduction color to be reproduced. As there are innumerable color separation ink quantity sets that can give an arbitrary reproduction color, the provisional color separation ink quantity set is determined by establishing a certain specific condition. For example, in this ...

example 2

C2. Example 2 of Color Separation Process in Embodiment 1

[0109]FIG. 12 is a flowchart depicting a processing routine in a second Example. In Example 1 described previously, primary color system input values per se are employed as the reproduction colors (the colors of the reproduction color system); in Example 2, however, colors of higher saturation than input colors are employed as the reproduction colors. The reason this is possible lies in the fact that the spot color inks R, V included in the reproduction color system can achieve higher levels of saturation as regards to red color and violet color than color mixtures of chromatic primary color inks.

[0110]In Step S100 in FIG. 12, an ink set composed of the chromatic primary color inks C, M, Y and the spot color inks R, V as useable inks is established.

[0111]Next, in Step S110, an ink duty limit, which limits ink quantity, is established for each color of the ink set. Ink duty limit is established with reference to type of ink and...

case 1-1

(Case 1-1) The temporary ink quantity pair color coordinate point Prv is located inside permissible range RA.

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PUM

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Abstract

Utilizing an ink set that includes a plurality of chromatic primary color inks that, when used in combination, can reproduce achromatic color, and at least one spot color ink of hue different from any of the plurality of chromatic primary color inks. Color to be reproduced on a print medium according to any one input color is termed “reproduction color”, and the combination of ink quantities in the ink set for reproducing the reproduction color on the print medium is termed the “color separation ink quantity set.” The ink quantity of the spot color ink included in the color separation ink quantity set is adjusted in accordance with a lightness parameter value which is correlated to lightness of reproduction color, so as to reduce ink quantity at a rate of change greater than the rate of change of the lightness parameter in the direction of increasing brightness.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application is a continuation of U.S. patent application Ser. No. 10 / 773,087, filed on Feb. 4, 2004, the disclosure of which is hereby incorporated by reference in its entirety.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]This invention relates to a color printing technique employing a plurality of inks.[0004]2. Description of the Related Art[0005]In recent years, color ink jet printers have come to enjoy widespread use as image output devices. A typical color ink jet printer employs, in addition to black (K) ink, several kinds of ink of the hues cyan C, magenta M, and yellow Y. Any color in a color image can be reproduced using these several kinds of ink.[0006]In a printer of this kind, ink amounts of each useable ink are determined according to an arbitrary color of the color image. Herein, the process of determining ink amount of each ink used in printing for color reproduction in this manner will be referred to ...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): H04N1/60H04N1/54
CPCH04N1/6033H04N1/54
Inventor YOSHIZAWA, KOICHIYAMAMOTO, YUKO
Owner SEIKO EPSON CORP
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