TILT ANGLE ADJUSTING METHOD FOR DYNAMIC PRESSURE BEARING, AND OPTICAL DEFLECTING DEVICE

• Main Authors: GAN MASAO, TAKAHASHI YUKO, ITO TOYOJI, IWAMURA YOSHIO
• Format: Patent
• Language: English
• Published: 17.05.1996
• Edition: 6
• Subjects: BEARINGS; BLASTING; CORRECTION OF TYPOGRAPHICAL ERRORS; ELEMENTS OR CRANKSHAFT MECHANISMS; ENGINEERING ELEMENTS AND UNITS; FLEXIBLE SHAFTS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVEFUNCTIONING OF MACHINES OR INSTALLATIONS; HEATING; i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; LIGHTING; LINING MACHINES; MECHANICAL ENGINEERING; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; PERFORMING OPERATIONS; PHYSICS; PRINTING; ROTARY BODIES OTHER THAN GEARING ELEMENTS; SELECTIVE PRINTING MECHANISMS; SHAFTS; STAMPS; THERMAL INSULATION IN GENERAL; TRANSPORTING; TYPEWRITERS; WEAPONS

PURPOSE: To stably obtain an image of high quality without requiring to enhance machining precision and assembly precision by adjusting balance weight at a proper position on a rotor, generating deflected swing rotation canceling a tilt angle, and minimizing the substantial tilt angle of a mirror at a photodetection position. CONSTITUTION: A polygon mirror is combined with a rotor base 121, a magnet 126, etc., to form the rotor 120, which rotates as a motor through the dynamic pressure bearing. At this time, such a swing rotation is generated under the influence of the unbalance of the rotor that appears as substantial tilt angle variation. For the purpose, the angle of the swing rotation due to the unbalance of the rotor after assembly and the tilt of the respective mirror surfaces of the polygon mirror at the photodetection position are measured, weight to be added to the rotor and its position are specified through calculation based upon the measurement results, and the weight is added to vary the swing rotation angle and phase of the rotor, thereby minimizing the substantial tilt angle of the mirror surfaces at a scanning position (photodetection position).