| 摘要 |
PURPOSE:To eliminate the generation of the whistling sounds arising from the air resistance at angle parts, the deformation of deflection reflecting surfaces, the limitation to the high-speed rotation by motor load, etc., by forming the vertex parts where the respective sides of a regular polygonal shape intersect with each other to a straight or curved shape. CONSTITUTION:Effective ranges 8 corresponding to the required scanning regions on the surface to be scanned exist within the deflection reflecting surfaces 4 of the rotary polyhedral mirror. The angle parts which are off the above- mentioned effective ranges and do not contribute to the deflection scanning are cut in a straight line or curve to form the milder angle parts. Namely, the vertexes indicated by a symbol T are cut in a straight or curved shape. The generation of the whistling sounds arising from the air resistance at the angle parts, the deformation of the deflection reflecting surfaces, the limitation in high-speed rotation by the motor load, etc., are eliminated in this way. |
