Patent ID: 9041759
Filing Date: 2015-05-26
Classification: G02B

Abstract:
1. A laser scanning unit comprising: a laser light source that radiates first laser light and second laser light respectively in a first direction and a second direction which are opposite to each other; a rotating polygon mirror that reflects the first laser light radiated from the laser light source; a drive motor that rotates the rotating polygon mirror; an entry detection portion that detects entry of the first laser light at a predetermined position on a scanning path of the first laser light reflected by the rotating polygon minor; an intensity detection portion that is provided on the second direction side of the laser light source and detects an intensity of the second laser light radiated from the laser light source; an intensity adjustment portion that adjusts the intensity of the first laser light radiated from the laser light source, in accordance with a result of the detection by the intensity detection portion, during a predetermined second time after a predetermined first time has elapsed since the detection by the entry detection portion; and a drive control portion that, upon the adjustment by the intensity adjustment portion, drives the drive motor at a first rotation speed set in advance such that a return light entry timing when the first laser light reflected by the rotating polygon minor enters the intensity detection portion is included within either the first time or a period from when the second time has elapsed to the timing of the detection by the entry detection portion.