Automatic color separation system

Claim 1

A color printing machine for printing faithful color output copies of an original document having at least two discrete colored areas, said machine including: a xerographic imaging system comprising a photoconductor member, means for charging the surface of said member, optical means for forming successive latent electrostatic images of said original on the surface of said member, means for erasing selected portions of said latent image, means for developing the latent image in at least two colors, means for transferring said developed image to a copy sheet and means for fusing said transferred image, said imaging system further comprising: sensing means enabled essentially simultaneously with the forming of said electrostatic image for discriminating between colored areas of said original document and areas outside said colored areas and for generating electrical signals representative of said colored and noncolored areas, control means adapted to operate upon said sensing means output signals so as to generate and store electronic signal representing coordinates of said colored areas, said control means further adapted to operate said erase means so as to erase areas, during at least a first and second pass, of at least a first and second latent image, and to operate said developer means so as to develop the remaining latent image, following each said erase operation, with a desired color or black toner.