| 摘要 |
PURPOSE:To detect original sizes accurately with just one photodetector provided to a titled device by using a tripple mirror assemblage. CONSTITUTION:An original is placed in conformity with a reference line 15a between an original cover 16 containing a tripple mirror assemblage 13 and an original plate 15. A motor 18 is run, and the light from a light source 20 projected through a half mirror 10 is scanned from below the plate 15 along the assemblage 13. At this time, there is no reflected light from the assemblage 13 covered with the original and the reflected light from the assemblage 13 of the part where there is no original is reflected by a mirror 17, passes through a half mirror 19 and is inputted to a photodetector 21. Hence, the quantity of the light that the photodetector 21 receives varies with the part where there is the original and the part where there is no original, whereby the size of the original is detected surely. |
