| 摘要 |
PURPOSE:To maintain the image potential of a photoreceptor at a specified value and to increase the speed of copying by expressing the characteristics of the photoreceptor by a specified reference equation, determining the quantity of the light projected by an optical system for projecting an image and correcting the reference equation successively at every copying. CONSTITUTION:A pattern 4 for forming a reference latent image corresponding to the reflection density in the background part of original image is installed on the rear of a top plate 3 on the side where the scanning of glass 2 of an original platen starts, and a temp. detecting element 16 as an element for detecting the characteristics of the photoreceptor 1 is provided near the photoreceptor. The surface potential of the photoreceptor 1 is detected with a detecting element 14. The quantity of the light projected by an optical system 5 for projecting image (the value of the voltage applied on an exposure lamp 6) is determined approximately at the value expressed by a reference equation, and the surface potential and surface temp. from detecting circuits 15, 17 are conducted to a control means 18 for exposure in follow up to the change in the characteristics of the photoreceptor 1 according to a change in temp. or continuous copying, whereby the reference equation is corrected successively. |
