Scanner mirror shaft has convex ends fitting concave gas bearing

摘要

A shaft (5) holding a scanner polygonal mirror (11) is supported by a gas-bearing. The bearing consists of two support plates (1, 2) held apart by spacers (3, 4). The shaft ends fit into the bearings. One or both of the shaft end surfaces (6, 7) are convex-shaped and are aligned with the shaft (5) axis of rotation (8) and fit into matching concave recesses in the bearing surfaces (9, 10). The convex and concave surfaces are separated by a small gap. Either the concave shaft surfaces or the concave bearing surfaces incorporate a number of concave pimple identical depressions (22) whose depth t is equal or less than 20 m.