ELECTROPHOTOGRAPHIC DEVICE

摘要

PURPOSE:To achieve a prescribed amount of charge, by detecting the surface potential of a photoreceptor drum with an oscillation capacitance type potentiometer and controlling the power supply for charger. CONSTITUTION:When a shutter 3 is oscillated in about 10 cycles, a charge induced on an electrode 2 is changed with a charge 8 on a photoreceptor 4. An AC voltage generated to the electrode 2 is applied to the gate of a field effect transistor 1, then the gate current changes also, and the peak value is proportional to the surface potential of the photoreceptor. The power supply voltage of the charger is controlled so that the output signal of the transistor 1 reaches a reference value.