CONTINUOUS-TONE ELECTROSTATIC ELECTRO-PHOTOGRAPHY

An electrophotographic process was sought which would produce photographs equivalent in quality and appearance to photographs made by more conventional processes, but without the limitations of such processes. Research showed that the addition of Te to the Se of an electrophotographic plate can increase the over-all photographic speed by a factor of 17, and can extend the spectral response to cover all of the visible spectrum and some near IR. The electrical characteristics of both single- and double-layer Se-Te plates depend on sensitizing conditions. Suitable apparatus was constructed for processing Se- Te plates, including those which have rapid dark-decay rates. The processing of plates from sensitizing through development can be completed in less than 3 sec. A practical plate-sensitizing unit was built which employs a radioactive material and miniature batteries, and can sensitize a plate 15 sec. An adhesive- coated paper was obtained which seems a suitable medium to which electrophotographic powder images can be transferred. The paper requires neither moistening nor interleaving and is relatively inexpensive.