| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming device which accurately reproduces density gradations by controlling the surface potential of a photosensitive drum 28 such as an amorphous silicon drum without being influenced by dark attenuation. SOLUTION: A developing device moving mechanism 15 retracts a developing unit 2 vertically upward and then a potential sensor moving mechanism 16 moves a potential sensor 1 toward the horizontal photosensitive drum 28; and the potential sensor 1 faces an area wherein a developing sleeve 3 faces the photosensitive drum 28 and a controller 14 controls the value of a current applied to a primary electrostatic charger 21, the quantity of exposure by a laser 22, and the mean value of developing biases applied to the developing sleeve 3 according to the surface potential measured at this position by the potential sensor 1. |
