| 摘要 |
PURPOSE:To restore the developer concn. automatically to a proper concn. by providing an exposure means which exposes the surface of an image carrying body at the nonimage exposure, a developer concn. detecting means and a control means controlling the exposure means according to the developer concn. CONSTITUTION:A light source 12 is so designed that the same potential as the latent image potensial obtainable on a photosensitive drum by exposure of the white ground part of an original is formed. It is put out at the light image exposure and is lighted in the operation period of still the primary, secondary and other corona dischargers although the image forming step has ended. In order to adjust the developer concn. by utilizing the light source 12, a developer concn. detecting means 13 and the control means 14 for the light source 12 are provided. In this way, the effect of permitting the automatic restoration of the developer concn. having increased too much to a proper concn. is obtained with the simple constitution. |
