Abstract: A light deflecting electric motor includes a stator assembly including a base, a fixed shaft fixed to the base and a stator mounted on the base, a rotor assembly including a rotating member rotatably mounted on a plurality of bearings further mounted on the fixed shaft, a polygon mirror mounted on the rotating member and a rotor mounted on the rotating member, the rotor assembly having a center of gravity located between the bearings, and a balancing plane provided in the vicinity of a plane which is generally perpendicular to a center of rotation of the rotor assembly and passes the center of gravity of the rotor assembly.

Abstract: A bearing supporting a rotational shaft of an electric motor includes an outer ring, an inner ring, and an annular retainer disposed between the outer and inner rings for holding a plurality of metal balls so that the balls are rollable. The retainer has a plurality of grease reserve portions formed in its upper end. Each grease reserve portion is enclosed partially by a peripheral wall. The gross amount of grease injected into the bearing is about 10% or less of a volume of an inner space of the bearing defined by the outer and inner rings and upper and lower sealing plates with the retainer and the balls in position.