| 摘要 |
PURPOSE:To speed film winding operation without fear of a position shift, by using an optical detecting means consisting of a projector and a photodetector and by detecting variations in the quantity of light occurring as perforations run. CONSTITUTION:A projector 3 consists of an LED element which emits infrared rays in a prescribed direction on the lower edge of a film 1 running by being wound, i.e., a part (perforation part 4) where perforations 2-2 are provided. Then, a photodetector 5 consisting of a photoelectric converting element, such as a phototransistor, photodetects the reflected light of the infrared rays projected upon the perforation part 4 by the projector 3. An optical detecting means consisting of the projector and photodetector mentioned above is used to detect variations in the quantity of light occurring as the perforations run, thereby speeding winding operation without any shift in position. |
