LIGHT SCANNING DEVICE

摘要

A first ftheta lens is arranged to form an inclination angle alpha1 to a main scanning plane. A second ftheta lens is arranged to form an inclination angle alpha2. In order to determine the inclination angles alpha1 and alpha2, curvature amounts of scanning lines generated on a scanned surface are measured when the ftheta lenses are independently inclined one at a time at a minute angle. Change rates K 1 and K 2 are obtained from the measured curvature amounts and the minute angles. The inclination angles alpha1 and alpha2 are determined such that |K 1 alpha1 +K 2 alpha2 | is no more than a certain value.