| 摘要 |
PROBLEM TO BE SOLVED: To prevent deterioration in image quality caused by the image density adjustment by changing potential difference between the developing potential and the exposing potential while fixing the potential difference between the non-exposing potential and the developing potential, and adjusting the developer feeding quantity to an exposing part. SOLUTION: This device is constituted so as to control a grounding potential selecting part 26 by a controller 32, for making ether potential difference between the developing potential and the exposing potential changed while fixing the potential difference between the non-exposing potential and the developing potential. The grounding potential selecting part 26 is composed of two Zener diodes of the same characteristic, i.e., the first Zener diode ZD1 and the second Zener diode ZD2, and a first switch 28 and the second switch 30, and adjusts the exposing potential on a photosensitive drum 10 by selecting one among a first path P1 to the third path P3. In such a manner, the developer charged in reverse polarity is prevented from sticking to the non-image area at the image density adjusting time, hence the image quality deterioration can be prevented. |
