| 摘要 |
PURPOSE:To prevent the deterioration of a photosensitive body by projection of unnecessary laser light to the photosensitive body and to prevent the degradation in the life of a cleaning mechanism by stopping the impression of a voltage of the photosensitive until a reference signal for scanning start of laser light is obtd. CONSTITUTION:A laser beam printer printing start control circuit keeps CHARGE ON AND BIAS ON signals turned off to open a switch 8 and a switch 10 and to prohibit impression of the voltage to the photosensitive rum 1 before the RDY-P signal indicating the end of the search actions of respective beams is outputted. An electrostatic latent image is not formed on the photosensitive rum 1 to which the electrostatic charge voltage is not impressed by off of the switch 8 even if the laser light 2 is projected on the drum and, therefore, the image is not developed to a visible image by a developing machine 3 and the degradation in the life of the cleaner 6 is obviated. The purpose of keeping the bias voltage of the developing machine 3 turned off during the off of the switch 8 is to prevent the full-surface development by the equivalence to that the entire surface of the photosensitive drum 1 is irradiated by the laser light 2 as the potential of the drum 1 is 0 volt during this time. |
