To enables an image forming apparatus which synthesizes additional data to document image data to detect the additional data having been synthesized.
A synthetic means/image processing means 204 after synthesizing the additional data to the document image data outputs the synthetic image to an image judgement means 201 in an image reader 109. The image judgement means 201 judges whether the additional data are embedded in the synthetic image by comparing a plurality of kinds of prepared additional data with the composite image one after another. When the additional data are detected in the synthetic image, a print instruction signal 208 is output to a printing means 206 to print the synthetic image. When no additional data are detected in the synthetic image, the image judgement means 201 does not output the print instruction signal and the synthetic image is not printed. Further, notice of alteration is given to a display device etc.
YOSHIDA YOSHIHARU
KIKUCHI MASAHIKO
SUZUKI NOBUAKI
TAKAHASHI KENICHI
YAMAZAKI HIDEKI
BANDO YOSHIBUMI
