| 摘要 |
PROBLEM TO BE SOLVED: To provide an image exposing device which can be manufactured at lower cost and can perform light exposure while the focus of a light beam is suitably adjusted. SOLUTION: The image exposure device 100 comprises an exposure light source 1, a lens 20 which images a light beam L emitted by the exposure light source 1, a recording material S, a rotary drum 10 which holds the recording material S, a driving mechanism 30 which drives the lens 20 along the optical axis, a distance sensor 40 which detects the distance between the recording material S and an exposure surface Sa, and a control part 50 which outputs a driving command signal to the driving mechanism 30 and forms an image on the exposure surface Sa while repeating a horizontal scan along the circumference of the rotary drum 10 and a vertical scan along the rotary shaft 11 of the rotary drum 10. The control part 50 calculates the mean value of the distance up to the exposure surface Sa corresponding to a specified quantity of rotation of the rotary drum 10 in the rotating direction according to the detection result of the distance sensor 40 and outputs the driving command signal for moving the lens 20 to an in-focus position according to the mean value. COPYRIGHT: (C)2003,JPO
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