Patent ID: 8922856

Claim:
An image forming apparatus which forms, by a plurality of printing scans, an image on an identical region of a printing medium for each color component, the apparatus comprising: a printing head; an input unit adapted to input image data; a separation unit adapted to separate the input image data into scan data for each scan of the plurality of printing scans by separating a pixel value, for each pixel in the input image data, into each scan of the plurality of printing scans; and an N-ary unit adapted to generate a dot pattern formed by applying N-ary processing, N is an integer not less than 2, to the scan data obtained by the separation unit based on predetermined constraining condition information, wherein the predetermined constraining condition information is set so that low frequency components of the dot pattern generated by the N-ary unit are in opposite phase with respect to low frequency components of a dot pattern printed on the identical region of the printing medium, and wherein the separation unit separates the input image data based on a predefined duty division ratio.