| 摘要 |
PURPOSE:To prevent the excess surface potential by measuring the pause time of a photosensitive material, determining the restoration amt. of electrostatic chargeability by the pause and decreasing an impressed voltage during recording in the stage of detecting the electrostatic charge potential of the photosensitive material and controlling the voltage to be impressed to an electrostatic charger in such a manner that the detection charge potential attains a target value. CONSTITUTION:A potential sensor 4 connected to a control part 9 is provided between an exposing device 1 for generating an electrostatic latent image on the belt-like material 2 and a developing device 3 which sticks a toner to said material and visualizes the latent image to detect the surface potential of the material 2 in the stage of said exposing device and developing device in the moving direction of the material 2. An electrostatic charger 5 having a corona wire 6 and a grid 7 is disposed on the upper stream side of the device 1 and the high voltage from a high-voltage power source part 8 controlled by a control device 9 is impressed thereto. A dark current control device is constituted in the above-mentioned manner. The pause time is measured when the photosensitive material 2 for image recording is paused. The restored surface potential is then detected by the sensor 4 and is subjected to calculation by a computer having a coefft. table, by which the potential to be impressed to the charger 5 is lowered. The good-quality image is thus obtd. immediately after the pause. |
