| 摘要 |
PURPOSE:To enable the size of an original to be detected at a high speed and in details without deteriorating the durability of a light emitting element. CONSTITUTION:Reflection type sensors S1, S2 and S3 are supported by a moving frame moved in a scanning direction A. Then, a reflection type sensor S4 is fixedly arranged near the terminating end position of the scanning direction A side of an original platen. Based on the outputs of the sensors S2 and S3, the size of the longitudinal direction of the original is detected. The size of the lateral direction thereof is detected by driving the moving frame in the scanning direction A and scanning a section between a scanning start position PS and a scanning end position PE by the sensor S1. At this time, the light emitting elements of the sensor S1 are driven at certain time intervals. On the other hand, the moving speed of the moving frame is reduced in a section between a deceleration position PD and the scanning end position PE. Thus, the size of the original can be detected with high resolution by the sensor S1 in the section between the position PD and the position PE. |
