| 摘要 |
PURPOSE:To obtain copy images which differ in image reproducibility with good response by switching selectively plural developing devices which are provided at the periphery of an electrostatic latent image carrier and charged with developers differing in toner density, and developing images. CONSTITUTION:The 1st and the 2nd developing devices 10 and 20 develop an electrostatic latent image formed on the surface of a photosensitive drum 1 which is driven to rotate as shown by an arrow (a) and those developing devices 10 and 20 has magnetic brush type structure and are different only in toner density between their internal developers. The surface of the drum 1 is exposed firstly to a negative image charged electrostatically to, for example, -600V to form an electrostatic latent image and a developing bias of, for example, -500V is applied to either of sleeves 11 and 21 of the developing devices 10 and 20 to stick negatively charged toner on image parts of the electrostatic latent image, thereby forming a positive developed image. |
