Color printing

• US 7,457,015 B2
• Filed: 05/18/2005
• Issued: 11/25/2008
• Est. Priority Date: 05/18/2005
• Status: Expired due to Fees

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Yao, Meng, Snyder, Trevor J., Gordon, Michael C., Kroon, Stephen M.
• Primary Examiner(s): Zimmerman; Mark K
• Assistant Examiner(s): Tsang; Elbert
• Application Number:
  US11/132,465
• Publication Number:
  US 20060268294A1
• Time in Patent Office: 1,287 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, 382/167
• US Class Current: 358/518
• CPC Class Codes: H04N 1/52 Circuits or arrangements for halftone screening

Abstract

A method of processing cyan, magenta and yellow color values including half-toning cyan and magenta colors values, and half-toning yellow color values in such a manner that yellow dots tend to be printed next to cyan, magenta or secondary color dots regardless of cyan, magenta, or yellow coverages.

Claims

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

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

transforming the C1, M1, Y1 color values to continuous tone data of the color values 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 B, Cout, and Mout, and a second threshold array A1′

for Y, wherein the second threshold array A1′

is a replica of the first threshold array A1 that is shifted in at least one of a horizontal/vertical, left/right, or up/down direction relative to the first threshold array A1 by one pixel.

2. The method of claim 1 wherein half-toning B, Cout, Mout and Y comprises half-toning B, Cout, Mout and Y using:

If B>

t,  

 

C, M dots are on Else if B+Cout>

t,  

 

 

C dot is on Else if B+Cout+Mout>

t, M dot is on If Y>

t′

, Y dot is on

wherein t is a threshold value of the first threshold array A1 and t′

is a threshold value of the second threshold array A1′

.

3. The method of claim 1 wherein half-toning B, Cout, Mout and Y comprises half-toning B, Cout, Mout and Y using:

If B>

t,  

 

C, M dots are on Else if B+Mout>

t,  

 

 

M dot is on Else if B+ Mout+Cout>

t, C dot is on If Y>

t′

, Y dot is on

wherein t is a threshold value of the first threshold array A1 and t′

is a threshold value of the second threshold array A1′

.

4. The method of claim 1 wherein transforming C1, M1, Y1 comprises:

C=C1

M=M1

Y=Y1

If C>

VMAX, set C=VMAX

If M>

VMAX, set M=VMAX

If Y>

VMAX, set Y=VMAX.

5. The method of claim 1 wherein obtaining blue, cyan and magenta output color values B, Cout, Mout such that B+Cout+Mout=VMAX comprises obtaining blue, cyan and magenta output color values B, Cout, Mout using:

B=C+M−

VMAX

Cout=VMAX−

M

Mout=VMAX−

C.

6. 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 continuous tone data of the color values 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; and

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

for Y, wherein the second threshold array A1 ′

is a replica of the first threshold array A1 that is shifted relative to the first threshold array A1 by one pixel.

7. The method of claim 6 wherein half-toning B, Cout, Mout and Y using a first threshold array A1 for B, Cout and Mout, and a second threshold array A′

for Y comprises half-toning B, Cout, Mout and Y using;

If B>

t,  

 

C, M dots are on Else if B+Cout>

t, C dot is on Else if B+Cout+Mout>

t,  

 

 

M dot is on If Y>

t′

, Y dot is on

wherein it is a threshold value of a first threshold array A1, and t′

is a threshold value of a second threshold array A1′

.

8. The method of claim 6 wherein half-toning B, Cout, Mout and Y using a first threshold array A1 for B, Cout and Mout, and a second threshold array A′

for Y comprises half-toning B, Cout, Mout and Y using;

If B>

t,  

 

C, M dots are on Else if B+Mout>

t, M dot is on Else if B+Mout+Cout>

t,  

 

 

C dot is on If Y>

t′

, Y dot is on

wherein t is a threshold value of a first threshold array A1, and t′

is a threshold value of a second threshold array A1′

.

9. The method of claim 6 wherein transforming C1, M1, Y1, K1 comprises:

C=C1+K1

M=M1+K1

Y=Y1+K1

If C>

VMAX, set C=VMAX

If M>

VMAX, set M=VMAX

If Y>

VMAX, set Y=VMAX.

10. The method of claim 6 wherein obtaining blue, cyan and magenta output color values B, Cout, Mout such that B+Cout+Mout=VMAX comprises obtaining blue, cyan and magenta output color values B, Cout, Mout using:

B=C+M−

VMAX

Cout=VMAX−

M

Mout=VMAX−

C.

11. A method of processing cyan, magenta and yellow color values comprising:

half-toning cyan and magenta colors values;

half-toning yellow color values in such a manner that yellow dots tend to be printed next to cyan, magenta or secondary color dots regardless of cyan, magenta, or yellow coverages.

12. The method of claim 11 wherein:

half-toning cyan and magenta color values comprises half-toning cyan and magenta color values using a threshold array A1;

half-toning yellow color values comprises half-toning yellow color values using a threshold array A1, wherein the threshold array A1′

is a one pixel shifted replica of the threshold array A1.