Patent ID: 9522554
Filing Date: 2016-12-20
CPC Classification: B41J,G06K

Claim Text:
1. An image printing apparatus for printing an image comprising: a print head including an ejection port array having a plurality of ink ejection ports arranged in an arranging direction to eject ink; a scanning unit configured to relatively scan the print head over a printing medium with the print head in a scanning direction that crosses the arranging direction a plurality of times; a conveying unit configured to relatively convey the printing medium in a conveyance direction that crosses the scanning direction between scans of the print head performed by the scanning unit, so that a first area in which an image is printed in K (K≧2) scans of the print head and a second area in which an image is printed in (K+1) scans of the print head are arranged in the printing medium in the arranging direction, a plurality of first ejection ports arranged at one end of the ejection port array in the arranging direction form an image in the second area in a first scan of the (K+1) scans, and a plurality of second ejection ports arranged in the other end of the ejection port array in the arranging direction form an image in the second area in a second scan that differs from the first scan of the (K+1) scans; an acquiring unit configured to acquire first image data corresponding to the ejection ports other than the first ejection ports and the second ejection ports and second image data corresponding to at least the first ejection ports and the second ejection ports; a generating unit configured to generate first print data used for printing an image in the K scans over the first area on the basis of the first image data and K first mask patterns each having print permitting pixels and non-print permitting pixels therein and corresponding to one of the K scans over the first area, and second print data used for printing an image in the (K+1) scans over the second area on the basis of the second image data and (K+1) second mask patterns each having print permitting pixels and non-print permitting pixels therein and corresponding to one of the (K+1) scans over the second area; and an ejection control unit configured to cause the print head to eject ink into the first area in accordance with the first print data generated by the generating unit in each of the K scans, and cause the print head to eject ink into the second area in accordance with the second print data generated by the generating unit in each of the (K+1) scans, wherein (i) among the (K+1) second mask patterns, each of the second mask patterns corresponding to the first ejection ports and the second mask patterns corresponding to the second ejection ports is formed from a plurality of first pixel group areas and a plurality of second pixel group areas, each of the first pixel group areas being formed by both of the print permitting pixels and the non-print permitting pixels disposed therein, and each of the second pixel group areas being formed by only plurality of the non-print permitting pixels disposed therein, wherein (ii) each of the first pixel group areas of the second mask pattern corresponding to the first ejection ports is disposed at a position corresponding to one of the second pixel group areas of the second mask pattern corresponding to the second ejection ports, and each of the first pixel group areas of the second mask pattern corresponding to the second ejection ports is disposed at a position corresponding to one of the second pixel group areas of the second mask pattern corresponding to the first ejection ports, and wherein (iii) each of a print permission ratio for the second mask pattern corresponding to the first ejection ports and a print permission ratio for the second mask pattern corresponding to the second ejection ports is lower than each of the print permission ratios for each of the K first mask patterns, the print permission ratio being a ratio of a number of print permitting pixels to a sum of the number of print permitting pixels and a number of non-print permitting pixels, and wherein (iv) each of the print permission ratio for the second mask pattern corresponding to the first ejection ports and the print permission ratio for the second mask pattern corresponding to the second ejection ports is lower than each of the print permission ratios for each of K−1 second mask pattern corresponding to a part of ejection ports other than the first ejection ports and the second ejection ports.