| 摘要 |
PURPOSE:To reduce the size of an auxiliary light source and to permit exact correction of a quantity of light by detecting the electrostatic latent image potential formed by the auxiliary light source by a potential detecting means and correcting the quantity of light of the auxiliary light source to maintain the specified potential. CONSTITUTION:The electrostatic latent image corresponding to the image of an original 11 is formed by an exposing part 10 on a photosensitive body 1. On the other hand, the specified quantity of light is projected by the auxiliary light source 20 to the non-image part where the electrostatic latent image is not formed, by which a patch is formed. This light source 20 receives the supply of electric power for lighting from a means 22 for controlling the quantity of light. The potential of the electrostatic latent image is thus detected by the potential detecting means 21. The detection output is inputted to the means 22 for controlling the quantity of light when the latent image potential is detected. The means 22 compares the actual detection output and reference potential and corrects the quantity of light of the light source 20 so as to reduce the difference if there is such difference between the two values. The light source 20 and the means 231 can be made into the smaller constitution and the execution of the correction of the quantity of light with high accuracy is permitted if the light source 20 is controlled in such a manner. |
