| 摘要 |
PURPOSE:To obtain an original scanning controller for variable power copying which prevents unnecessary exposure and takes a continuous copy securely by using a sensor to stop a scan which exceeds the length of the effective copy area of a photosensitive body. CONSTITUTION:A rotating disk 17 rotates in synchronization with the photosensitive drum 2 and has a rear end timing mark to be detected by the sensor 18 when the exposure position of the photosensitive body coincide with the rear end of the effective copy area of the photosensitive body. Then, a means which stops an original scan when either of timing mark detection by the sensor 18 or the completion of the original scan is earlier and drives a return operation device for an original placing plate 8 or optical systems 9-11 is provided. Consequently, the original scan is stopped once the exposure position reaches the rear end of the effective copy area of the photosensitive body 2 even in case of a large enlargement rate, and the original placing plate 8 or optical systems are returned forcibly. |
