| 摘要 |
PURPOSE:To obtain always good images by controlling applied voltage based on the surface potentials of a recording medium at the forming of latent images. CONSTITUTION:The standard bright part surface potential VL, main motor drive signal DRMD and roller bias control signal RBTP are applied to terminals T2, T6, T7 respectively and the signals are all ''H'' during latent image developing and therefore transistors Trs 17, 18 go ON and FETQs 12, 13 go OFF and the bright part surface potential VL inputs to an operational amplifier Q11 through resistances R105, VR 13. The output of the Q11 is applied to the fixed point of the primary coil of a transformer T12 through a current booster consisting of Trs 15, 16 and the developing bias voltage VN is changed according to the potential VL by inverter circuits VINV, SINV. At this time, the voltage VN is so controlled by the circuits SINV, VINV that it becomes +50V of the potential VL on the drum. Thereby, the good images free from fog, etc. in the background may be obtained. |
