| 摘要 |
PURPOSE:To control a developed image to constant density and to improve its quality by varying a bias voltage applied to a developing means synchronously with potentials of areas on a photosensitive body which are charged electrostatically for transfer and not charged when a positive image is formed from an original negative image. CONSTITUTION:A driving circuit 21 applies driving voltages HV-, HV+, and HAC to a charger, charger 5, and developing sleeve 4a and blade 4b respectively under the command of a microcomputer 20. A waveform shaping circuit 22 shapes the waveform of the signal of a sensor 8 which detects whether a transfer material P is prevent or not and sends the resulting signal to the microcomputer 20. When the relay RY1 of a bias voltage setting circuit 23 is on, a constant voltage Vcc is divided through a resistance R1, variable resistance VR, and resistance R2 and outputted as a remote signal VREM to the driving circuit 21, which increases or decreases the developing bias to adjust image density. |
