| 摘要 |
PURPOSE:To provide a device whicn can discriminate information abnormality by forming the surface potential of the polarity reversed from that of the 1st surface potential on a photoreceptor, and exposing the same at the quantity of light of ternary levels. CONSTITUTION:An electrostatic charger 2 and a lamp 3 are turned on simultaneously to charge an insulation layer 1c negatively. Since a photoconductive layer 1b is conducted for the purpose of full surface exposure, the positive charge from a conductive substrate is injected into the layer 1b and the positive charge distributes at the interface between the layer 1c and the layer 1b. The insulation layer is applied with the secondary charging of the polarity reversed from that of the primary charging by way of an electrostatic charger 4 so that the surface potential is inverted from negative potential to positive potential. A three-layered photoreceptor 1 of such a state is exposed by the information wherein the quantity of light has 3 stages of levels, whereby the positive and negative electrostatic latent images corresponding to black and red information are formed. |
