ROTARY DRIVING APPARATUS FOR POLYGON MIRROR

PROBLEM TO BE SOLVED: To provide a rotary driving apparatus for polygon mirror in which an air flow rectification member is arranged at a proper position, thus the air flow, which is made non-uniform in the circumferential direction of the rotation of a polygon mirror due to the rotation of the polygon mirror which takes in the air into a projected part, is turned into a streamlined flow, the motion of a rotor supporting the polygon mirror is suppressed and the plane tilt of the polygon mirror and the deterioration of jitter value are prevented. SOLUTION: The rotary driving apparatus for polygon mirror comprises: a polygon mirror 2; the rotor 31 which supports the polygon mirror 2; a motor 3 which rotationally drives the rotor 31; and a cover member 4 which covers the polygon mirror 2 and is provided with an open part 41 for passing a laser beam. The cover member 4 is provided with a projected part 44 which is projected to surround the periphery of the open part 41 and the air flow rectification member 6 is formed at the front side end part 48 of the open part 41 in the rotating direction of the polygon mirror 2. COPYRIGHT: (C)2007,JPO&INPIT