Patent ID: 7048357

Claim:
A printing method comprising the steps of: providing a print head having a plurality of nozzle arrays, each of the nozzle arrays having a plurality of nozzles arranged along a sub-scanning direction for discharging a same ink, at least one pair of nozzle arrays for discharging different inks being positioned such that nozzles of the nozzle array pair are arranged in a staggered manner, the staggered nozzle array pair consists of a leading nozzle array that reaches a leading edge of the printing medium relatively earlier and a trailing nozzle array that reaches the leading edge relatively later when the sub-scan is performed; (a) performing interlace recording where only a plurality of main scan lines separated one another are recorded by each nozzle array in a single main scan pass, and where recording of successive main scan lines is achieved by a plurality of main scan passes that include at least one sub-scan feed therebetween; and (b) in the interlace recording, referring to the printing data memory prior to a main scan pass, for printing data of a plurality of main scan lines that correspond to an overall width in the sub-scanning direction of the staggered nozzle array pair, and performing the main scan pass according to the referenced printing data wherein the step (a) comprises the step of: (c) performing sub-scan feed such that a same main scan line is not recorded by two nozzles having a same ordinal nozzle number in the staggered nozzle array pair, but the same main scan line is recorded by two nozzles haying different ordinal nozzle numbers in the staggered nozzle array pair.