Patent ID: 8517494

Claim:
A printing apparatus that performs printing while relatively moving a print head in a main scanning direction and a sub scanning direction with respect to a printing medium, the printing apparatus comprising: a nozzle row that is installed on the print head and is acquired by aligning a plurality of nozzles, which ejects ink, in the sub scanning direction; a halftone processing unit that performs a halftone process by comparing each threshold value of a dither mask that is formed by a plurality of threshold values with image data that configures an image; and a printing unit that performs printing by controlling ejection of ink from each nozzle of the nozzle row by using a result of the halftone process, wherein a correspondence relationship between each position in a minimal repetition unit of a nozzle pattern indicating a nozzle out of the plurality of nozzles that is used to form a dot in each position on the printing medium and each threshold value of the dither mask that is applied to the each position is set to be constant, wherein the dither mask includes at least one side of nozzles that are disposed on both ends of the nozzle row or frontmost-end nozzles that serve as nozzles disposed on both ends of the nozzle row in a print area having a predetermined range of an ink duty ratio, and wherein the plurality of threshold values are set such that a use ratio of front-end nozzles that is a ratio at which the front-end nozzles, which are disposed within a predetermined width from the at least one side of the frontmost-end nozzles, eject ink is lower than a use ratio of middle nozzles that is a ratio at which middle nozzles, which are acquired by excluding the frontend nozzles from the plurality of nozzles, eject ink.