Method and apparatus for polygon mirror scanning capable of performing a stable high speed polygon mirror rotation

摘要

A high speed rotating apparatus including a shaft, a rotary body, and a motor. The rotary body driven by the motor has a hollow into which the shaft is inserted and forms a dynamic pressure air bearing between the rotary body and the shaft. The rotary body includes first and second rotary members. The first rotary member has an inner circumferential surface held for rotation by the dynamic pressure air bearing. The second rotary member has an inner circumferential surface fixed to the outer circumferential surface of the first rotary member through a hardening insertion process. The hardening insertion process is performed such that a tensile strength of the first rotary member is greater than an axial tensile stress to be produced in the inner circumferential surface of the first rotary member.