| 摘要 |
PURPOSE:To allow a toner to stick to only a necessary area by setting a bias voltage applying means to an ON state, only while the electrified area of a photosensitive body is passing through the vicinity of said means. CONSTITUTION:A photosensitive drum 1 is electrified by an electrification corotron 2, about the center part of an electrified area is exposed selectively by an exposing means 3, and an electrostatic latent image is formed. As a result, on the upstream side and the downstream side of the latent image, only electrified area A, B are formed. Subsequently, while the area A passes through the vicinity of a developing sleeve 4, a developing bias relay 5 becomes an ON state, and while the area B passes through the vicinity of the sleeve 4, the relay 5 becomes an OFF state. In such a way, a toner does not stick to an emergency electrified area of the outside of the areas A, B, and the areas A, B have also the same polarity as the toner, therefore, the toner does not stick but sticks to only a necessary area. |
