Patent ID: 7298506

Claim:
A color image forming apparatus comprising: a reading section which reads an image on a paper by a scanner, and outputs a plurality of coloring matter information signals; a collating section which collates the plurality of coloring matter information signals from the reading section with a specific image including paper money and securities, and determines whether or not there is a same portion in order to prevent counterfeiting; a delay section, without a memorizing function, that receives said plurality of coloring matter information signals, and has delay times which are different for each of said plurality of coloring matter information signals in consideration of time spent on collation processing by the collating section respectively; an eliminating section which, when the collating section determines that the same portion as in the specific image is included in the image information, substantially eliminates at least the same portion from the image information outputted from the delay section and outputs it; and an image forming section has a plurality of independent image forming structures which carries out image formation on a recording medium in accordance with the plurality of coloring matter information signals.