Patent Document ID: 20090284775
Application ID: 12464166
Patent Status: 0

Claim One:
1. An image forming apparatus for generating a copy-forgery-inhibited pattern image which includes a latent image area drawn using a large dot pattern and a background area drawn using a small dot pattern, the latent image being encoded and embedded in the copy-forgery-inhibited pattern image as an additional information, comprising: a large dot pattern decision unit, configured to read a test pattern image printed using a plurality of large dot patterns, recognizes encoded additional information embedded in each test pattern by decoding the additional information, obtains a recognition rate of the additional information and an average density of each test pattern, and decides, as a large dot pattern for recording, a large dot pattern used for a test pattern whose recognition rate and average density fall within a predetermined range and are close to predetermined reference values; a small dot pattern decision unit, configured to read a test pattern image printed using a plurality of small dot patterns, obtains an average density of each test pattern, and decides, as a small dot pattern for recording, a small dot pattern used for a test pattern whose average density falls within a predetermined range and is close to the average density of the large dot pattern for recording; and a print image generator, configured to generate a copy-forgery-inhibited pattern image by drawing a foreground using the large dot pattern for recording which is decided by said large dot pattern decision unit and contains predetermined encoded additional information and drawing a background using the small dot pattern for recording which is decided by said small dot pattern decision unit, and combines the copy-forgery-inhibited pattern image with a print target image.