| 摘要 |
PURPOSE:To form a nonimage region with excellent precision on a photosensitive body regardless of the density state of an original by carrying out the variable control to a blank exposing region according to th density of the original. CONSTITUTION:This image forming device is provided with an optical medium enlarging light projected from an exposing means 2c and projecting it on the photosensitive body, an original density detecting means S4 detecting the density of the original, and an adjusting means 2a automatically adjusting the focal point of spot light projected from the exposing means 2c while moving the optical medium based on the detected density of the original. Even when the density of the original is lighter than a prescribed one, or darker than the prescribed one, a surface potential on the photosensitive body 11 corresponding to a specified trimming region can be erased with the excellent precision. Thus, an erasing exposure can be always carried out with the excellent precision on a specified region regardless of the original density. |
