| 摘要 |
PURPOSE:To obtain a clear picture quality prevented from the generation of dirt and reduced in noise even if the same paper is repeatedly copied by exposing a charged photosensitive substance when the size of paper is different from that of an original to be transferred, and then discharging an unnecessary area for copying on the surface of the photosensitive substance. CONSTITUTION:The surface of a photosensitive drum 28 is positively charged by driving a main charger 81 and light having intensity corresponding to the density of an original led by an optical system 27 is irradiated on the drum 28 to form a latent image. A latent image formation area is moved to a developing part 26A in accordance with the rotation of the drum 28, an unnecessary part for copying on the drum is discharged by driving a reverse bias charger 82 arranged in front of the part 26A synchronously with the rotation of the drum 28. Consequently, a high quality of copied paper which is completely prevented from dirt other than a part on which the original is copied is obtained, and even if the contents of another original are copied in the space part of the copied paper thereafter, a fine picture quality can be obtained as the whole paper. |
