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Summary:
Recent developments at the RCA Research Laboratories, Princeton, New Jersey, have resulted in several new electrophotographic components and systems of great potential interest in the graphic arts. The Electrofax process for direct electro-photographic printing on paper utilizes a photoconductive coating comprising a special low-cost Zinc oxide pigment dispersed in a resin binder, coated on a paper base. A photographic print is produced by placing a uniform electrostatic charge directly on the coated paper surface, exposing to a light image, causing the charge to drain away in proportion to intensity of the light incident on a given portion of the surface, and developing the image by use of a magnetic brush consisting of a thermoplastic resin powder carried on a brush of iron filings. Several additional experimental graphic arts applications using the basic components of the Electrofax system are described in this article. These include experimental high-speed Electrophotographic procedures for the direct application of Electrofax materials and techniques to the production of photolithographic plates, dry offset plates, Ietterpress plates, printed circuit boards and electrophotographic transparencies. Photographic sensitivities usable for production of offset or typographic printing plates or in general photo-resist applications are of the order of 10,000 to 100,000 those of standard dichromate or diazo-sensitized materials. Projection printing of master copy or resist patterns is easily possible. Photographic development is dry, rapid and capable of high resolution.