Abstract: An optical deflection apparatus includes: a base member; a coil fixed to the base member; and a rotor unit rotatable to the base member, having a bearing member, a rotating body provided on the bearing member, having reflection surfaces, and a magnet provided on the rotating body in a position facing the coil. Either the magnet and the rotating body or the bearing member and the rotating body are adhered together by an adhesive agent whose Young's modulus after hardening is not more than 100 N/mm2.

Abstract: A rotary apparatus includes: a radial fixed member; a rotary unit rotatably supported on the radial fixed member; a radial dynamic pressure bearing portion at which the radial fixed member faces the rotary unit; and dynamic pressure generating grooves formed on the radial dynamic pressure bearing portion. The dynamic pressure generating grooves are asymmetrically formed with respect to a rotary axis of the rotary unit.

Abstract: There is described a light beam deflection apparatus in which the distortion of the polygon mirror is reduced, and the mounting accuracy of the polygon mirror is improved. The light beam deflection apparatus includes a base plate, a coil being stationary relative to the base plate and a mirror unit being rotatable with respect to the base plate. The mirror unit includes a polygon mirror, a rotating disk to mount the polygon mirror, a rotating yoke fixed to the rotating disk, a magnet attached to the rotating yoke and located opposite the coil and a buffer member inserted into a gap between the polygon mirror and the rotating yoke.

Abstract: An optical deflection device includes: a rotor having reflection surfaces on a cirumferential surface thereof; a bearing for rotatably supporting the rotor; a magnet fixed on the rotor; a supporting member for supporting the bearing, on which a radiating fin is integrally formed; and a coil fixed on the supporting member at a position where the coil faces the magnet for forming a magnetic field.

Abstract: In an assembling method of an optical deflection apparatus in which a polygonal mirror is fixed on an outer ring of a radial bearing and an optical scanning is conducted by a rotation of an inner ring of the radial bearing, the assembling method includes the steps of placing the polygonal mirror on the outer ring of the radial bearing wherein the polygonal mirror and the outer ring of the radial bearing have an engagement portion including an adhering portion with a gap having a distance between the polygonal mirror and the outer ring of the radial bearing; adjusting a tilt angle of the polygonal mirror with respect to the outer ring of the radial bearing; and filling an adhesive in the gap of the adhering portion under the adjusted condition, thereby integrally fixing the polygonal mirror and the outer ring of the radial bearing.

Abstract: In a rotating device which comprises a rotor; a radial bearing; a lower thrust bearing; a dynamic pressure generating means, a radial bearing area (mm.sup.2) which is the area of the rotor facing the radial bearing, a thrust bearing area (mm.sup.2) which is the area of the rotor facing the lower thrust bearing, and the rotor weight (g) are determined so as to satisfy the following formula:(a radial bearing area)/(thrust bearing area).times.(rotor weight)<300.

Abstract: An apparatus for supporting a rotator, comprises a radial bearing and a thrust bearing, wherein at least one of a radial bearing surface, a supported surface of the rotor facing the radial bearing surface, a thrust bearing surface and a regulated surface of the rotor facing the thrust bearing surface is a rough surface having a center-line mean roughness not less than 0.3 and a surface facing the rough surface is a smooth surface having a center-line mean roughens less than 0.3.