| 摘要 |
PURPOSE:To obtain a light utilization factor sufficiently, and realize an ftheta correction and high resolution in spite of a prizm unused simple constitution in a post-objective type scanning optical system. CONSTITUTION:Assuming that a distance from a main scanning directional light source side principal point position to a semiconductor laser 1 is S and a distance from a sub scanning directional light source side principal point position to the semiconductor laser 1 is S', an anisotropic refracting power single lens 2 capable of satisfying S>S' is arranged between the semiconductor laser 1 arranged so that the direction of a large radiation angle can coincide with the main scanning direction and a cylindrical surface polygon 5 whose reflecting surface is formed in a cylindrical surface, and a correcting lens 6 whose sub scanning directional refracting power is varied from the center to the periphery in the main scanning direction, is arranged between the cylindrical surface polygon 5 and a photosensitive drum 7. |
