Patent ID: 8303070
Filing Date: 2012-11-06
Classification: B41J

Abstract:
1. An ink jet printing apparatus comprising: a print head including a first ejection opening array arranged in a predetermined direction and formed by first ejection openings for ejecting first ink droplets and a second ejection opening array arranged in the predetermined direction and formed by second ejection openings for ejecting second ink droplets which have a smaller volume than a volume of the first ink droplets; a control unit that causes the print head to scan over a predetermined area of a print medium in a forward direction and a backward direction, crossing the predetermined direction, an odd number of times in total to form an image on the predetermined area, a length of the predetermined area of the print medium being equal to or less than a length of at least one of the first and second ejection opening arrays in the predetermined direction; and a defining unit that defines ratios for ejecting the first ink droplets in each of the scans of the print head and ratios for ejecting the second ink droplets in each of the scans of the print head, wherein the defining unit defines the ratios for ejecting the first ink droplets so that the ratio in one of the even-numbered scans is higher than that in one of the odd-numbered scans, and wherein a first difference between a total of the ratios of all the even-numbered scans and a total of the ratios of all the odd-numbered scans for the first ink droplets is smaller than a second difference between a total of the ratios of all the even-numbered scans and a total of the ratio of all the odd-numbered scans for the second ink droplets.