Patent ID: 7656554

Claim:
A method for correcting neutral color shift in a production cartridge for use in an imaging system, comprising: determining a colorant increment data by a controller based on a standard cartridge neutral variation signature color data and a standard cartridge neutral sensitivity signature color data associated with a standard cartridge, and based on a production cartridge neutral variation signature color data and a production cartridge neutral sensitivity signature color data associated with said production cartridge; and using said colorant increment data to correct said neutral color shift, wherein the neutral variation signature color data is obtained by: selecting m evenly spaced neutral variation points along a neutral axis from white point diagonally to black point; and printing the selected neutral variation points to measure a device independent L*, a*, and b* values, and wherein the neutral sensitivity signature color data is obtained by: selecting n points from the m neutral variation points; and determining three points around each of the n selected points, each of three determined points varies only in one of three colorant C, M, and Y by a small amount, such that m and n both are integers and m is greater than n.