Digital color proofing system and method for offset and gravure printing

摘要

A proofing system incorporates an image member having a dielectric surface and a write head for writing a pattern of electrostatic image dots on the surface. A controller is provided for controlling the write head in response to digital data representing an original document so that the image dots of the pattern may have variable field strengths and form a latent electrostatic image of the document on the surface. The controller also controls the areas of the image dots written on the surface in accordance with the digital data. An inking head presents an electrostatic ink to the surface whereby the surface acquires ink only at the image dots thereon in amounts proportional to the field strengths of the image dots so as to develop the latent image on the surface. A printing substrate is supported and pressed against the image member surface so that the ink is released from the surface to the substrate thereby producing a proof copy of the original document consisting of a pattern of print dots with variable gray scale values and/or sizes so that the system may produce proof copies composed of patterns of dots which emulate the printing structure produced by an offset press or a gravure press.