Rotor dynamics of polygonal mirror scanner motor supported by air bearings in digital electrophotography

摘要

A mathematical analysis has been performed on rotor dynamics of a high speed polygonal mirror scanner motor in digital electrophotography. The roto is assumed to be rigid and vertically supported by air bearings whose effective length is not negligible compared to the rotor length. The model is a four-degree-of-freedom system which includes the gyroscopic effect, the radially unstable magnetic stiffness of a driving motor and/or a magnetic bearing, and nonorthogonal force of the air bearing with finite length. A simulation program was coded to calculate complex eigenvalues, static and dynamic stability, critical speeds, unbalance responses, and external excitation responses. The model is utilized to realize high performance scanner motors.