ABSTRACT
Many of the early attempts to create electrostatic charge patterns were based on the photoelectric effect (Selenyi, 1938c; Carlson, 1940; Sukumlyn, 1942; Dimmick, 1947). The photoelectric effect is the process by which electrons are ejected from a solid by the absorption of radiation. An early patent issued to Carlson (1940) describes the process. In the 1920s and 1930s, several attempts were made to use photocurrents to control chemical changes in specially treated papers (Hana, 1920; Wilcke, 1920; von Bronk, 1922; Goldmann, 1937; Schmieschek and Klutke, 1939). From results of these studies, Carlson concluded that chemically based phenomena of this nature were not feasible with the magnitude of photo currents that could be produced under conditions of practical interest. As a result, Carlson and Kornei began to experiment with processes based on the creation of electrostatic latent images on surfaces of photoconducting insulators. Results of these experiments led to the discovery of an image forming process that Carlson later called “electrophotography.”
