Patent ID: 7357473

Claim:
A printer comprising: a print head having nozzles that form dots on a print medium; an image data acquiring unit that acquires image data having pixel values each having M gray scales (where, M≧2); a nozzle characteristic information storage that stores nozzle characteristic information representing characteristics of the nozzles; a nozzle specifying unit that specifies a nozzle concerned with banding generation in the print head, based on the nozzle characteristic information; a banding prevention processor that performs a banding prevention process for data corresponding to a banding generation line constituted by dots formed by the nozzle concerned with the banding generation and a different line constituted by dots formed by a different nozzle near the nozzle concerned with the banding generation in the image data to reduce deterioration of print quality due to the banding; a banding prevention processing controller that controls the banding prevention processor so that a process range of the banding prevention process in the banding prevention processor includes the banding generation line and the different line in the image data, a density difference of density values of a line adjacent to the different line falling within a predetermined numerical range; and a printing unit that prints an image on the print medium by means of the print head, based on the image data that are subjected to the banding prevention process.