Patent ID: 8848014

Claim:
A polygon mirror assembly comprising: a polygon mirror formed of a plastic material and having a plurality of reflection surfaces; a motor unit to support and rotate the polygon mirror, the polygon mirror being coupled to the motor unit by an adhesive material; and a holder frame coupled to a rotation axis of the motor unit, the polygon mirror being coupled to the holder frame by the adhesive material, wherein the polygon mirror comprises a hole, a part of the holder frame being inserted into the hole, and the adhesive material uniformly covers an entire innermost diametrical surface of the polygon mirror defining the hole, and wherein a tilt preventing step having a space to accommodate adhesive material discharged from between the polygon mirror and an outer surface of the holder frame is formed in the innermost surface of the polygon mirror, the tilt preventing step being a groove formed on a lower circumferential surface of the innermost surface of the polygon mirror.