A novel electrophotographic system.

A novel electrophotographic system is described which consists of a thin film of a transition metal oxide and a thin film photoconductive layer sandwiched between a pair of electrodes. When an electric field is applied across this composite structure and an optical image is projected on it, the resulting modulation of the conductivity pattern in the photoconductive layer causes a similar coloration pattern in the oxide layer, thereby forming a visible image. The formation of color centers and the associated optical and electrical properties are discussed.