DYNAMIC PRESSURE FLUID BEARING DEVICE AND POLYGONAL SCANNER UNIT HAVING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a dynamic pressure fluid bearing device which a lubricant can be retained inside within the bearing on the extended period of time. SOLUTION: In the dynamic pressure fluid bearing device which uses an oil, or the like, etc., as a lubricant, the device comprises a shaft and a sleeve having the dynamic pressure forming grooves on either one of the opposed bearing surfaces of the shaft and the sleeve. An oil repelling treatment is carried out on the inner surface of the sleeve or at the outer surface of the of the outside near the sliding contact surface of the device and it is characterized that the gradient oil repelling treatment is carried out on the bearing surface from the inside to the outside potion in the direction of the axis so that the oil repellency of the outside potion is much stronger than the inside portion.