Patent ID: 8427708
Filing Date: 2013-04-23
Classification: H04N

Abstract:
1. An image forming apparatus comprising: an image reader configured to read an original document including an original image and an original additional image to provide document image data; an image processor configured to extract original image data in correspondence to the original image from the document image data read by said image reader and create output image data based on the extracted original image data; and a printer configured to perform printing based on the output image data created by said image processor to produce an output document; wherein the original additional image is printed with greater visibility in the output document than in the original document when the printing is performed under unauthorized conditions due to vanishing of a part of the original additional image during reading by the image reader resulting from the part of the original additional image comprising dots smaller than a recognizable resolution of the image reader; and wherein said image processor adds first data to the extracted original image data to create the output image data when the printing is performed under authorized conditions, the first data forming a first additional image that is the same as the original additional image when the output image data is printed.