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US 6,742,870 B2Granted
Selective enhancement of black
AssigneeXerox Corporation
InventorStephen M. Kroon
Life of this patent
Estimating the term…
Abstract
A printing technique wherein pixel locations that are requested to be marked with only black are identified, black is applied to the identified pixel locations, and non-black color is applied to a subset of the identified pixel locations that correspond to on-pixels of a reference pattern of non-black color pixels having an on-pixel population of at least 20 percent and a toner transfer efficiency of less than about 20 percent.
Claims41
A method of printing comprising:
- identifying pixel locations on a print output medium that are requested to be marked with only black;
- electrophotographically printing black at the identified pixel locations;
- electrophotographically printing at least one non-black color only at each of pixel locations of a subset of those identified pixel locations that correspond to on-pixels of a reference pattern of non-black color pixels having an on-pixel population of at least 20 percent and a toner transfer efficiency of less than about 20 percent, wherein each non-black color pixel of the reference pattern is of at least one non-black color, and wherein the at least one non-black color for a pixel location is defined by the at least one non-black color of a corresponding non-black color pixel of the reference pattern;
- whereby black is printed by itself without a non-black color at identified pixel locations other than the subset of the identified pixel locations that correspond to on-pixels of the reference pattern of non-black color pixels.
1 more element
A method of printing comprising:
- identifying pixel locations on a print output medium that are requested to be marked with only black;
- printing black at the identified pixel locations;
- after printing black, printing a non-black color only at a subset of those identified pixel locations that correspond to on-pixels of a reference pattern of non-black color pixels having an on-pixel population of at least 20percent and a toner transfer efficiency of less than about 20 percent, wherein each non-black color pixel of the reference pattern is of at least one non-black color, and wherein the at least one non-black color for a pixel location is defined by the at least one non-black color of a corresponding non-black color pixel of the reference pattern;
- whereby black is printed by itself without a non-black color at identified pixel locations other than the subset of the identified pixel locations that correspond to on-pixels of the reference pattern of non-black color pixels.
1 more element
A method of printing comprising:
- identifying pixel locations on a print output medium that are requested to be marked with only black;
- electrophotographically printing black at the identified pixel locations;
- electrophotographically printing a non-black color only at a subset of those identified pixel locations that correspond to on-pixels of a reference pattern of non-black color pixels having an on-pixel population of at least 20 percent and a toner transfer efficiency of less than about 20 percent, wherein the reference pattern comprises three mutually exclusive single color sub-patterns, one each for cyan, magenta and yellow, and wherein a non-black color for a pixel location is defined by a color of a corresponding non-black color pixel of the reference pattern;
- whereby black is printed by itself without a non-black color at identified pixel locations other than the subset of the identified pixel locations that correspond to on-pixels of the reference pattern of non-black color pixels.
1 more element
Dependencies are inferred from the claim text.