Research progress in electrophotography in the U.S.S.R. and Eastern Europe

A review of the latest investigations carried out in Bulgaria, East Germany, Poland, and the U.S.S.R. is presented. The discharge mechanisms both in dark and under illumination are being analyzed for two types of electrophotographic layers--with a binder and without it. In both cases, the discharge mechanism does not only depend on the layer type, its structure and technology, but also on the conditions of charging and discharging. It is shown that the photo-discharge mechanisms of selenium electrophotographic layers and of zinc oxide layers with binder differ in principle. The characteristics of As-Se electrophotographic layers and electrophotographic process with an effective quantum yield exceeding unity have been considered. Some works investigating the prospects of application of organic photoconductors in electrophotography have been reviewed. Information on the electrophotographic copiers and electrophotography for medical purposes is also provided.