Richard J Bartlett, Age 75Hampstead, NH

3982935, Sep 28, 1976

Aug 1, 1974

5/494013

Richard F. Bartlett - Burlington MA
Laura K. Case - Winchester MA

Itek Corporation - Lexington MA

G03G 1322
G03G 506

96 1R

This disclosure relates to an electrophotographic copying process suitable for use in a multiple copying system. The process is characterized by use of an electrophotographic medium comprising photosensitive organic compounds which are either (1) insulating prior to irradiation and substantially permanently conductive subsequent to irradiation or (2) conductive prior to irradiation and substantially permanently insulating subsequent to irradiation. The process comprises the steps of exposing the electrophotographic medium to a pattern of activating radiation to produce a latent image with a conductivity pattern that is irreversible and permanently altered and externally applying an electrical charge at any suitable time thereby forming an electrostatic pattern which can be developed by any of the known electrophotographic developing techniques. By consecutively repeating the steps of charging and developing, an indefinite number of prints can be made which are comparable in image quality and density to the original with a single step of exposure to the pattern of activating radiation. Consequently, a multiple copy system results which is substantially faster than conventional electrophotographic systems due to elimination of a requirement for repeated exposure of the electrophotographic medium to a source of activating radiation for each copy.