DYNAMIC PRESSURE AIR BEARING TYPE POLYGON SCANNER, AND PROCESSING METHOD FOR DYNAMIC PRESSURE AIR BEARING TYPE POLYGON SCANNER

摘要

PROBLEM TO BE SOLVED: To provide an inexpensive, high-precision dynamic pressure air bearing type polygon scanner which uses a radial dynamic pressure air bearing and a suction type axial magnetic bearing, and to provide a processing method for the dynamic pressure air bearing type polygon scanner. SOLUTION: A hollow rotary shaft 11 of the dynamic pressure air bearing type polygon scanner 1 has at least its dynamic pressure air bearing part 11a and polygon mirror part 11c formed integrally of a metal material consisting principally of aluminum; and the hollow rotary shaft 11 has a polygon mirror processing reference surface formed orthgonally to the dynamic pressure air bearing part 11a and the surface of the dynamic air bearing surface is processed. Thus, the dynamic air bearing part 11a and polygon mirror part 11c of the hollow rotary shaft 11 are formed integrally of the metal material consisting essentially of aluminum without being processed by providing shrink p arts respectively, so the hollow rotary shaft 11 can be formed at a low cost with high precision by decreasing its constitution component and a polygon surface is prevented from being strained to have worse flatness, thereby maintaining a high-precision mirror surface.