| 摘要 |
PURPOSE:To easily compensate even a characteristic change of each process element and to maintain its stable record density by detecting the potential of an electrostatic latent image formed on a charge carrier, the optical density of a visual image obtained by developing the latent image, image density on recording paper, etc., and controlling different process elements. CONSTITUTION:The excitation level of an exposure lamp provided to an optical scanning system, the corona current flowed to an electrostatic charger 10, the toner density of a developing device 12, developing bias voltage applied to the developing sleeve of the developing device 12, the corona current flowed to a transfer charger 14, and the voltage applied to a separating charger 15 are controlled respectively so as to adjust the image density. Those respective process elements are brought under independent closed-loop control, but the device is composed of a double closed-loop control system on the whole. the large control system detects the outputs of a surface potential sensor SE1 which detects the potential of the electrostatic latent image formed on the photosensitive drum 3 and the output of an optical sensor which detects the optical image of the image visualized through the developing device 12, thereby setting control commands of the small control system. |
