| 摘要 |
PURPOSE:To improve the reliability in detecting an original size by providing plural light emitting elements which exist below a transparent plate for placing an original and irradiate the transparent plate according to the size to be detected of the original and photodetectors which receive the light reflected from an original cover during closing. CONSTITUTION:An original platen 1 consisting of a transparent plate and an original cover 2 having a reflecting surface 4 are so constituted that the light emitted from light emitting elements 5 and reflected by the surface 4 in the mid- way of closing the cover 2 is condensed onto a photodetector 6. When an original 8 is placed on said plate here, the light irradiated from the element 5 is scattered by the original 8 and spreads as shown by dotted lines thus the light incident to the photodetector 6 at the point B is limited. The positions where the element 5 and the photodetector 6 are installed is selected like, for example, 51-54 for the light emitting element and 61-65 for the photodetector in accordance with the original size then the presence or absence of the original and the size thereof are detected by finding the combination of the output condition from the photodetectors 61-65. The reliability in the direction is consequently improved. |
