Abstract: An improvement in the method and apparatus for producing a multi-color electrophotographic image wherein an electrophotographic medium can be used for multiple charge-expose cycles without the accumulation of trapped charges which can result in an increase in toe voltage. The invention provides for the charging, exposing and toning of the medium to produce a first color visible image. The carrier is then returned to the first position to repeat the foregoing steps to charge, expose and tone to produce a second color visible image. Prior to the second charging step the medium is reverse charged and trapped charges are neutralized to substantially revitalize the medium to a condition closely resemblng its unused condition to substantially eliminate the rise in toe voltage.

Abstract: Electrophotographic color proof generating apparatus includes a charger station, an exposure station, and a development station. Starting with color half-tone separations of artwork, the apparatus, using a unique method, electronically controls the exposure and potentials at the charger and development stations to generate a proof. The apparatus is designed to generate proofs which match the dot gain or loss and density of press sheets printed by a great variety of commercial presses starting with the same separations as are used to form the proofs. The separations are then modified until the apparatus generates a proof which is an acceptable reproduction of the artwork. The modified separations are then used to generate a press sheet on the commercial press which will be an acceptable reproduction of the artwork.