Patent Document ID: 7961355
Application ID: 12004419
Patent Status: 1

Claim One:
1. A printing method of printing on a printing medium, comprising: providing a print head that includes a plurality of nozzle arrays for ejecting at least N colors of inks, N being an integer of at least 3; performing a halftone process with a dither matrix on image data that represents a tone value for each pixel making up an original image to generate dot data that represents a state of dot formation at each pixel of a print image to be formed on the printing medium; and generating the print image by combining at least N colors of dot groups formed in at least one scan of the print head in a common print area, the plurality of nozzle arrays respectively forming dot groups having different colors from each other in the each scan of the print head according to the dot data, wherein the dither matrix includes a single reference matrix that is set by determining threshold values in the reference matrix based on a predetermined index value, said predetermined index value being calculated based on an arrangement pattern of at least two colors of dot groups among M colors (M is an integer of at least 3 and less or equal to N) of dot groups among the at least N colors of dot groups, with respect to at least some tone values among the input tone values, and the performing includes N different halftone processes, each of the N different halftone processes being performed on each of the at least N colors of inks by using the dither matrix that includes the reference matrix and (N−1) converted matrices generated by executing one of at least one type of predetermined conversion process (N−1) times on the reference matrix.