| 摘要 |
PURPOSE:To improve the rotating accuracy of a polygon mirror by conducting fitting of the inner ring and outer ring of a ball bearing on the operating side and the inner ring of a ball bearing on the non-operating side through a rest fit and fitting of the outer ring thereof through a loose fit and by bringing an axial pre-load spring and a radial lateral-pressure spring into contact with said outer ring of the ball bearing on the non-operating side. CONSTITUTION:Fitting of the inner ring and outer ring of a ball bearing 3a on the operating side and the inner ring of a ball bearing 3b on the non-operating side is conducted through a rest fit and fitting of the outer ring of the ball bearing 3b on the non-operating side, through a loose fit; and an axial pre-load spring 11 and a radial lateral-pressure spring 33 are brought into contact with the outer ring of the ball bearing 3b on the non-operating side. Because said pre-load spring 11 is added in the direction of a rotating shaft 24 therefore, rolling elements (balls) roll in both bearings 2a, 2b by an appropriate pre-load without any space from rolling surfaces (inner and outer rings). As a result, the rotating shaft 24 is settled in the center of rotation relative to the both bearings 2a, 2b so that its rotating accuracy is improved and its vibration is eliminated. Accordingly, the rotating accuracy of a polygon mirror 8 is improved too. |
