| 摘要 |
PURPOSE:To offer a rotary polygon mirror which has excellent mirror surface accuracy up to the end part of a mirror surface and can have its beam reflection area set widely and a metallic mold for molding the rotary polygon mirror. CONSTITUTION:Side cores 12a-12d of the metallic mold is segmented by segmenting lines extending outward from corner parts where mutually adjacent mirror surfaces 1a-1d of the rotary polygon mirror 1 cross each other. When fused resin is injected, gas gathering at the corner parts 2 is discharged from fine gaps of the segmenting lines and the transfer property of the fused resin to side core internal surfaces is improved. |
