| 摘要 |
PURPOSE:To always keep the surface potential on an image carrying body constant by controlling the dark potential of the image carrying body by applying a constant potential to a grid provided on a primary electrifier, detecting the bright potential of the image carrying body by a potential measuring sensor and adjusting an irradiating light quantity to the image carrying body based on this detected information. CONSTITUTION:In a light source output controller 3, potential information sent out of an electrometer 4 is detected whether it is varied from a prescribed potential or not, and when it is varied, the quantity of a light beam radiated from a light source 1 is adjusted by varying an output of a power source 2, and the surface potential of a photosensitive drum 9 is returned to the prescribed potential by changing the potential of a photoirradiation part. On the other hand, the electrified potential (dark potential) of the photosensitive drum 9 caused by a primary electrifier 14 is controlled by a grid 13 impressing a constant voltage which is decided with a power source 10. In this way, the surface potential of an image carrying body can be kept constant under any environment condition. |
