| 摘要 |
PURPOSE:To maintain copying conditions in an initial state by detecting the potential of the electrostatic latent image formed by a prescribed base line original, controlling quantity of electrostatic charge and exposure and controlling cleaning of an optical system. CONSTITUTION:A fine line part 6 consisting of fine black lines different from a wide-area black part 3 of a reference original 2 is provided to either the black part 3 or white part 4, i.e., the white part 4, etc. The potential of the electrostatic latent image formed on a photosensitive body 15 by the original 2 is detected by a surface potential detector 18. The quantity of charge, exposure and cleaning of stains in the optical system are controlled respectively by the surface potential of the latent image in the part 3, the surface potential of the latent image in the part 4, and the surface potential of the latent image in the part 6 via a measuring circuit 19, a comparator circuit 20, a control circuit 21, etc. The three conditions for copying are thus maintained always in the initial state and the adequate copying is accomplished. |
