LASER SCANNING DEVICE, IMAGE FORMING APPARATUS AND REFLECTION SURFACE IDENTIFICATION METHOD FOR IDENTIFYING REFLECTION SURFACE OF ROTARY POLYGON MIRROR

摘要

A laser scanning device includes a rotary polygon mirror, a drive motor, a light detecting portion, a measurement processing portion, and an identification processing portion. The rotary polygon mirror has reflection surfaces and rotates such that light is scanned by the reflection surfaces in sequence. The light detecting portion detects the light scanned by the rotary polygon mirror. The measurement processing portion, in each of light detection cycles, measures an interval between a light detection timing and an output timing at which a drive signal that is to be input to a drive motor first after the detection timing, is output. The identification processing portion identifies a reflection surface corresponding to a standard interval, based on the standard interval and the measured interval, the standard interval being one of intervals acquired in the detection cycles that correspond to the reflection surfaces.