Patent ID: 8950842
Filing Date: 2015-02-10
Classification: G06K

Abstract:
1. An image processing apparatus for printing dots in a pixel region of a print medium by causing a print head for ejecting ink to scan the pixel region a plurality of times, the image processing apparatus comprising: a mode setting unit configured to set a first printing mode for printing dots in the pixel region by N scans of the print head, where N is an integer of 2 or greater, and a second printing mode for printing dots in the pixel region by M scans of the print head, where M is an integer larger than N, at a print resolution higher than that of the first printing mode; a conversion unit configured to convert gradation data having K number of gradation levels corresponding to the pixel region into binary data corresponding to the pixel region by using a plurality of dot arrangement patterns which determine print or non-print of a dot in each of a plurality of areas in the pixel region with respect to each gradation level, where K is an integer of 4 or greater; and a generation unit configured to generate a plurality of ejection data corresponding to the plurality of scans based on the binary data by using a plurality of mask patterns, each of which having a print permitting area permitting printing of a dot and a non-print permitting area not permitting printing of a dot in each of the plurality of areas; wherein in a case that the first printing mode is set by the mode setting unit: (A-i) the conversion unit converts the gradation data into first binary data by using a K number of first dot arrangement patterns, each of which determines print or non-print of a dot at each of J number of first areas in the pixel region, where J is an integer of 2 or greater and is smaller than K-1, wherein a number of first area determined print of a dot in the first dot arrangement pattern corresponding to a first gradation level is the same as a number of first area determined print of a dot in the first dot arrangement pattern corresponding to a second gradation level which is one level higher than the first gradation level, (A-ii) the generation unit generates N number of first ejection data based on the first binary data by using N number of first mask patterns, each of which having a first print permitting area permitting printing of a dot and a first non-print permitting area not permitting printing of a dot in each of the J number of first areas arranged such that (i) a sum of the first print permitting areas in the N number of first mask patterns becomes K-1, and (ii) a sum of the first print permitting areas, in the N number of first mask patterns, corresponding to position of the first area determined print of a dot by the first dot arrangement pattern corresponding to the second gradation level is more than a sum of the first print permitting areas, in the N number of first mask patterns, corresponding to position of the first area determined print of a dot by the first dot arrangement pattern corresponding to the first gradation level, and (A-iii) the K number of first dot arrangement patterns and N number of first mask patterns are determined so as to be able to represent K number of gradation levels by printing dots in the pixel area according to N number of first ejection data by the N scans of the print head, and wherein in a case that the second printing mode is set by the mode setting unit: (B-i) the conversion unit converts the gradation data into second binary data by using K number of second dot arrangement patterns, each of which determines print or non-print of a dot at each of K-1 number of second areas in the pixel region, (B-ii) the generation unit generates M number of second ejection data based on the second binary data by using M number of second mask patterns, each of which having a second print permitting area permitting printing of a dot and a second non-print permitting area not permitting printing of a dot in each of the K-1 number of second areas arranged such that a sum of the second print permitting areas in the M number of second mask patterns becomes K-1, and (B-iii) the K number of second dot arrangement patterns and M number of second mask patterns are determined so as to be able to represent K number of gradation levels by printing dots in the pixel area according to M number of second ejection data by the M scans of the print head.