POLYGON MIRROR AND MOLD FOR MOLDING POLYGON MIRROR

摘要

A polygon mirror (10), comprising a reflecting surface group (14) having reflecting surfaces (M(1), M(2), ..., (Mn)) of (n) in quantity formed on the outer peripheral surfaces thereof, a flat surface part (12) closing one end part of the reflecting surface group, and pin gate marks (L(1), L(2), ..., L(n)) of (n) in quantity put on the flat surface part for each of the reflecting surfaces of (n) in quantity and part from edge parts where the reflecting surfaces cross the flat surface. Where the shortest distance between the edge part formed by crossing the reflecting surface M(n) with the flat surface and the pin gate mark L(n) is DM (n), and the shortest distance between the pin gate mark L(n) and the pin gate mark L(1) is DL(n), DM(1) > DL(1)/2, DM(2) > DL(2)/2, ..., DM(n) > DL(n)/2, and DM(1) > DL(n)/2, DM(2) > DL(1)/2,..., DM(n) > DL(n - 1)/2.