| 摘要 |
PURPOSE:To correct the distortion of a scanning line optically by converging luminous flux in an image forming direction only on the side of a light source about a main scanning deflector and also converging the light in a scanning direction even on the side of a surface to be scanned about the main scanning deflector as well. CONSTITUTION:Pieces of luminous flux emitted by light emission parts of a multipoint light emitting element 10 are transmitted through a collimator lens 11 to become pieces of parallel luminous flux which travel along an x-y plane and they enter a telecentric lens 20 through an aperture stop 21. Pieces of luminous flux exiting from the telecentric lens 20 are reflected and deflected by a reflecting surface 31 of a polygon mirror and enter a cylinder scanning lens 40 which has refracting power only in the deflecting direction. Namely, the respective pieces of luminous flux are converged by the telecentric lens 20 in a (y) direction and converged by the cylinder scanning lens 40 in a (z) direction to form independent spots on the surface 50 to be scanned. The (y) coordinates of those spots are determined by the light emission positions hy' of the multipoint light emitting element 10 and the (z) coordinates are determined only by the angle of rotation of the polygon mirror 30. Consequently, the two-dimensional image having no distortion is formed. |
