| 摘要 |
PURPOSE:To scarcely generate the deformation in a state attached to a rotation driving shaft, and to obtain a satisfactory optical performance by executing integral forming from a resin material, and finishing the fitting surface to the specular surface. CONSTITUTION:A rotary polygon mirror l is formed integrally by injection molding by using polycarbonate as a raw material, has a fitting hole 2 in the center, has four plane-like reflecting surfaces 3a, 3b, 3c and 3d in the periphery, and the fitting surface 4 is finished to the specular surface on which center line average roughness and the maximum roughness are <=0.1mum and about <=1.0mum, respectively. It is attached to a motor 10 by fitting loosely the fitting hole into a driving shaft 13, and tightening a screw 17 to the tip of the driving shaft 15 through a plate spring 15 and a washer 16. Accordingly, by finishing the fitting surface to the specular surface, adhesion of the fitting surface 4 and the seat surface 14a becomes satisfactory at the time of attaching it to the rotation driving shaft 13, the rotary polygon mirror itself is scarcely deformed, and an elapsed deformation is also extremely small. |
