| 摘要 |
PURPOSE:To prevent image density unevenness in the sub-scanning direction from occurring in recording image on photosensitive material. CONSTITUTION:A polygon mirror 264 rotated at rotation speed of 125 (rpm) while moving the photosensitive material so that a sub-scanning interval becomes 1.6X10<-2> (mm) executes main scanning by deflecting a light beam in the main scanning direction. An SOS(start of scanning) sensor 276 whose material and shape are set up so that the natural frequency fm becomes larger than 798(Hz) and smaller than 827(Hz) outputs a timing signal when the light beam corresponding to the vicinity of a main scanning start point which is reflected from an SOS mirror 275 is made indent on. A controller controls a light source so as to start main scanning from the main scanning start point based on a signal. An image forming optical system 270 forms image of the light beam deflected by the polygon mirror 264 on the photosensitive material. |
