| 摘要 |
PURPOSE:To perform accurate operation and to detect an original, although size is small and at low cost, by providing two original sensors, and putting those sensors in cooperation and detecting the presence or absence of the original and its width. CONSTITUTION:When there is no original between an LED 17 and optical fiber read ends 4a and 5a, light from the LED 17 is received by the original sensors as it is, but when there is some original present, the light from the LED 17 is not enter to the original sensor. Therefore, the presence or absence of the original is detected on the basis of whether the original sensors generate outputs or not. For example, the read ends 4a and 4b are set at positions corresponding to the widths of sizes A4 and B4; when an original of size A4 passes over the read ends 4a and 5a, the light incident toward the read end 4a is shielded by the original and the light to the read end 5a is not shielded. Then, the width of the original is detected on the basis of the difference between their detection signals. |
