| 摘要 |
PURPOSE:To perform exposure detection without generating deficiency of image and without decreasing the amount of light that contribute to image formation, by providing a light transmitting part in a part of reflecting plane of an in- mirror lens and providing a light detecting section behind it. CONSTITUTION:Light emitted from an exposure lamp is reflected by the surface of an original and arrives at mirrors 11, 12 and an in-mirror lens 13. Light rays that contribute to image formation arrive at a photosensitive body 15 through a mirror 14. A small opening 17 that forms a transmitting part is provided in the reflecting plane 16 of the in-mirror lens 13. Light incident on this small opening arrives at a photosensor 18 and exposure detection is performed. Accordingly, the exposure detection is performed without causing deficiency of the image and without decreasing the amount of light that contribute to image formation. |
