Color printing

• US 7,508,558 B2
• Filed: 05/18/2005
• Issued: 03/24/2009
• Est. Priority Date: 05/18/2005
• Status: Active Grant

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Yao, Meng, Snyder, Trevor J.
• Primary Examiner(s): Coles; Edward L
• Assistant Examiner(s): Baker; Charlotte M
• Application Number:
  US11/132,747
• Publication Number:
  US 20060268295A1
• Time in Patent Office: 1,406 Days
• Field of Search: 358/1.9, 358/518, 358/3.06, 358/3.03, 358/534, 358/3.23, 358/3.22, 358/3.13, 358/523, 358/535, 382/167, 382/162
• US Class Current: 358/523
• CPC Class Codes: H04N 1/6022 Generating a fourth subtractive colour signal, e.g. under colour removal, black masking

Abstract

A method of processing cyan, magenta, and yellow color values C1, M1, Y1 including transforming the C1, M1, Y1 color values to cyan, magenta, and yellow color values C, M, Y in such a manner that each of C, M, Y is not greater than a predetermined maximum value VMAX; obtaining blue, cyan and magenta output color values B, Cout, Mout by setting B=0, Cout=C, and Mout=M; if the sum C+M is greater than VMAX, obtaining blue, cyan and magenta output color values B, Cout, Mout such that B+Cout+Mout=VMAX; and half-toning B, Cout, Mout and Y using a first threshold array A1 for B, Cout and Mout, and a second threshold array A2 for Y.

Claims

1. A computer operable method of processing cyan, magenta, and yellow color values C1, M1, Y1, comprising:

receiving input values C1, M1, Y1 through use of input means;

transforming the C1, M1, Y1 color values color values cyan, magenta, and yellow color values C, M, Y in such a manner that each of C, M, Y is not greater than a predetermined maximum value VMAX;

obtaining blue, cyan, and magenta output color values by setting B=0, Cout=C, and Mout=M;

if the sum C+M is greater than VMAX, obtaining blue, cyan and magenta output color values B, Cout, Mout such that B+Cout+Mout=VMAX;

half-toning B, Cout, Mout, and Y using a first threshold array A1 for B, Cout and Mout, and a second threshold array A2 for Y, wherein the second threshold array A2 is a replica of the first threshold array A1, derived by shifting the first threshold array A1 by a predetermined number of pixels in one of a horizontal/vertical, a left/right, or an up/down direction, and wherein the first threshold array A1 and the second threshold array A2 are uncorrelated.

2. A computer operable method of processing cyan, magenta, Yellow and black color values C1, M1, Y1, K1 comprising:

receiving input values C1, M1, Y1, K1 through use of input means;

transforming the C1, M1, Y1, K1 color values to cyan, magenta, and yellow color values C, M, Y through use of the value K1 in such a manner that each of C, M, Y is not greater than a predetermined maximum value VMAX;

obtaining blue, cyan, and magenta output color values by setting B=0, Cout=C, and Mout=M;

if the sum C+M is greater than VMAX, obtaining blue, cyan and magenta output color values B, Cout, Mout such that B+Cout+Mout=VMAX;

half-toning B, Cout, Mout and Y using a first threshold array A1 for Cout and Mout, and a second threshold array A2′

for Y, wherein the second threshold array A2 is a replica of the first threshold array A1, derived by shifting the first threshold array A1 by a predetermined number of pixels in one of a horizontal/vertical, a left/right, or an up/down direction, and wherein the first threshold array A1 and the second threshold array A2 are uncorrelated.