| 摘要 |
PURPOSE:To reduce the number of used mirrors to reduce considerably the cost by providing a means where variable power is inputted, a means which detects the start position of scanning of a platen, and a means which controls the position of an optical system. CONSTITUTION:The device is so constituted that the first mirror 11 and a lens 12 are moved on a basis of a photosensitive body 14 in case of varying power, and a mount 25 of the lens 12 is moved by a motor 29 and a cable 28, and the mirror 11 is moved by a motor 24 and cables 22 and 23. The time when a sensor 30 indicating the position of the mirror 11 detects an actuator 31 attached to a moving platen 10 is defined as the scanning start position of the platen 10 to keep the positional relation between the platen 10 and the mirror 11 constant independently of reduction magnifications. Since only two mirrors 11 and 13 are used, expenses required for high-precision attachment of mirrors are reduced considerably. |
