| 摘要 |
PURPOSE:To prevent only an unintended black solid without fail by detecting the light quantity equivalent to the presence and the absence of an original over a sufficiently long distance prior to the exposure scanning for making a copy. CONSTITUTION:While an original platen 1 is driven from a waiting position to an exposure starting position, an illumination lamp 5 lights up, and therefore, a photo transistor 71 receives the rays of light by receiving the reflecting light of an original. Since 72 and 73 are corresponding to the position where the retaining plate is opened when there are no original, they hardly receive the rays of light. Consequently, the original platen 1 goes from the waiting position to the exposure starting position, the output C1 of the comparator 27 of an eraser driver 241 becomes L just before the platen arrives at the exposure start ing position, the output C2 of a comparator 242 becomes H, the output C3 of a comparator 243 becomes H, and the condition is maintained at an integrating circuit 26. Consequently, light emitting groups ER2 and ER3 light up, and a black solid recording corresponding to erase width of the light emitting diode group ER2 is prevented. |
