Electrophotographic contact duplicating apparatus and method

Abstract

Apparatus in which the photographic images on a strip roll of silver halide film are duplicated upon a strip roll of electrophotographic film. The apparatus feeds the strips of the two rolls into contact with one another, emulsion side of the photographic film against the coating side of the electrophotographic film. At the projection station there is a projected light beam passing through the contacting films. A charging station is provided for charging the electrophotographic film just before it contacts the photographic film and a toning station and a fixing station respectively are located to act upon the electrophotographic film after exposure. Alternatively, the toned image may be transferred to a strip of clear base film from the coated surface of the electrophotographic film followed by fixing of the transferred image. The electrophotographic film then is reused while the clear base film becomes the duplicate of the original. The method involves the use of an electrophotographic film which will not lose charge by virtue of contact or by static electricity because of the separation of the films after contact. The electrophotographic film is coated with a very thin layer of insulating hydrocarbon before the contact occurs to prevent static discharge when the films separate and for other reasons. Background density of the original film is measured by photometric means and compared with preset density standards or used to adjust the sensitivity of the electrophotographic film through charging to provide optimum duplicated quality.