Patent ID: 8508792

Claim:
A printing apparatus comprising a printing unit configured to print images on paper and to output the paper on which the images have been printed, the printing apparatus comprising; a generating unit configured to generate copy-forgery-inhibited pattern image data; and a rotation unit configured to rotate the generated copy-forgery-inhibited pattern image data in accordance with an output direction of paper, wherein the printing unit prints the generated and rotated copy-forgery-inhibited pattern image data or the generated and non-rotated copy-forgery-inhibited pattern image data on paper and outputs, in accordance with an output direction of the paper, the paper on which the generated and rotated copy-forgery-inhibited pattern image data or the generated and non-rotated copy-forgery-inhibited pattern image data has been printed, wherein the generating unit includes plural dithering matrices for generating copy-forgery-inhibited pattern image data, and wherein the plural dithering matrices include dithering matrices used for generating copy-forgery-inhibited pattern image data to be rotated by the rotation unit and dithering matrices used for generating copy-forgery-inhibited pattern image data not to be rotated by the rotation unit.