| 摘要 |
PURPOSE:To detect the change in the exposure of a photoreceptor owing to the stain of an exposing optical system and the brightness on the ground of an original accurately, by detecting the quantity of the light which is made incident to the photoreceptor by passing through the exposing optical system and is reflected from the original, directly. CONSTITUTION:A photoreceptor 6 is formed with a light transmission window 5 by facing a slit 5, and a reflecting mirror 8 is provided below the window 7. A photosensor 9 is disposed in the reflection light path of the mirror 8 by facing the same. The pictures of an original A set on an original plate 2 are exposed on the photoreceptor 6 which is driven in synchronization with the light source 3, through an exposing optical system 4 and the slit 5 when the source 3 is moved forward in an arrow (a) direction. When the source 3 is moved backward in an arrow (b) direction (in the stage of non-exposure), the light reflected from the original A is conducted through the system 4 and the slit 5 to the window 7, and is reflected to the photosensor 9 from the mirror 8. The quantity of the reflected light thereof (exposure) is detected. |
