| 摘要 |
PURPOSE:To obtain copied images whose image reproductivity shows difference over a wide range by changing the carried quantity of developer by a developer carried quantity changing means. CONSTITUTION:At the time of a line priority mode, a CPU 30 outputs a signal related to the rotating speed of a sleeve driving motor 35 to a sleeve driving circuit 36 through an I/O 34 and the rotating speed is set so that the ratio of the peripheral speed of a developing sleeve 14 to the one of a photosensitive body drum 1 becomes 1.5. Applied voltage to a screen grid 10 and the developing sleeve 14 is controlled. On the other hand, at the time of a half tone mode, the ratio of the peripheral speed of the developing sleeve 14 to the one of the photosensitive body drum 1 is made to be 1.8. Therefore, excellent copied images can be obtained whose image reproductivity varies in the line priority mode and in the half tone mode so as to fit to each image quality of an original. Thus, image reproductivity can be changed over the wide range. |
