Patent ID: 8330996
Filing Date: 2012-12-11
Classification: H04N

Abstract:
1. An image forming apparatus having a manuscript copy function, comprising: (a) a reading section for reading said manuscript having image data in which at least watermark information is plurally buried, said image data is formed in an image formation area; (b) a judging section for judging a degradation state of said watermark information by comparing said watermark information with predetermined standard information, said standard information being furnished in a predetermined position outside said image formation area of said manuscript and being read by said reading section; and (c) a controlling section for limiting a copy of said manuscript when said judging section judges that said watermark information is degraded, (d) wherein said judging section calculates a correspondence rate of said watermark information on the basis of the total number of said watermark information that are compared with said standard information and the number of said watermark information that correspond to said standard information, and judges that said watermark information are degraded when said correspondence rate is under a predetermined threshold value.