PURPOSE: To prevent uneven revolution, the inclination of a shaft, and the scattering of oil and grease and to maintain high accuracy by fixing and supporting at least rotating polygon mirror and a rotor for rotating and driving to a hollow revolving shaft which revolves by means of bearings around the central shaft which is held to a fixed member such as a housing.
CONSTITUTION: A central shaft 22 is fixed to a motor case 18 by means of a nut 23, and a hollow central shaft 11 is provided with a lower bearing 11 fixed to the shaft 22, and a freely vertically movable upper bearing 7 preloaded with a spring rest 37 and a spring 13 fixed to the shaft 22. A rotating polygon mirror 2, a rotor magnet 8 and balancing rings 15, 16 are fixed to the shaft 11. When electric current is flowed to a stator 9, the shaft 21 revolves. The bearings 7, 11 are positioned by one revolving shaft and since the shaft 21 is one cylinder, the uneven revolution and the inclination of the shaft are prevented and high accuracy is maintained. The scattering of oil and grease is prevented by closing the upper part of the shaft 21 with a cover 32.
KOMATSU TERUO
GOTOU SHINJI
