| 摘要 |
PURPOSE:To surely detect an original size and to avoid the damage of an origi nal by using an original cover means also as an original detection means. CONSTITUTION:Light is reflected on a part where the original 1 exists in a state where the original cover means 4 is opened and the reflected light is made incident on the photodetector part 6b of the original detection means 6, but the light is not reflected on a part where the original 1 does not exist and the reflected light is not made incident on the photodetector part 6b. There fore, it is possible to judge the size of the original based on size decision data according to which is the original detection means 6 that detects the reflected light. However, when a black image exists just at a detected spot by the means 6 because an image part exists on the original, the reflected light is not received and it is judged that the original does not exist, so that the original size can not be correctly recognized. By referring to the detected result by the means 6 in state where the means 4 is closed, the change of the detection signals at the time of opening the means 4 and at the time of closing it is obtained to judge the presence or absence of the original 1. At the time of judging that the original 1 exists, the size is decided by using a table expressing the relation between the detection signal of the means 6 and the original size. |
