Patent ID: 8079665

Claim:
A printing apparatus capable of ejecting ink to print an image on a printing medium comprising: a printing head including a plurality of arrays, each of which has a plurality of ejection openings which are arranged at a predetermined pitch in a first direction, the plurality of arrays being arranged in a second direction crossing the first direction; a scanning unit which moves the printing head relative to the printing medium in a direction crossing the first direction; and a controller which causes the printing head to eject ink during the movement of the printing head by the scanning unit, wherein the printing head has a plurality of first groups and a plurality of second groups: (i) each first group including an array of first large ejection openings and an array of first small ejection openings, where the first large ejection openings eject a greater amount of a first ink than the first small ejection openings, and (ii) each second group including an array of second large ejection openings and second small ejection openings, where the second large ejection openings eject a greater amount of a second ink, different from the first ink, than second small ejection openings, and wherein the plurality of first groups and the plurality of the second groups are arranged such that an alignment order of the first groups and the second groups are symmetrical in the second direction with respect to a center of the arrangement of the plurality of arrays of the printing head, and wherein the first large ejection openings of the plurality of first groups are arranged so as to be shifted with respect to the plurality of the first small ejection openings by one-quarter of the predetermined pitch in the first direction, and wherein the first large ejection openings of one of the plurality of first groups are arranged so as to be shifted with respect to the second large ejection openings of one of the plurality of second groups, located adjacent to said one of the plurality of first groups, by half of the predetermined pitch in the first direction, and wherein the first small ejection openings of one of the plurality of first groups are arranged so as to be shifted with respect to the second small ejection openings of one of the plurality of second groups, located adjacent to said one of the plurality of first groups, by half of the predetermined pitch in the first direction.