| 摘要 |
PURPOSE:To reduce the cost and facilitate the adjustment by composing a linear image formation optical system of a single lens which is symmetrically convex on its light source side and convex on its deflector side at right angles to a scanning surface. CONSTITUTION:A laser scanning device consists of a semiconductor laser 1 as a light source, the linear image formation optical system 2, a polygon mirror 3, an ftheta lens 4, a photosensitive drum 5, etc. Then the linear image formation optical system 2 consists of the single lens which is symmetrically convex on the side of the light source 1 about the optical axis and convex on the side of the deflector 3 at right angles to the scanning surface. Namely, luminous flux emitted by the light source 1 is made into nearly parallel luminous flux by forming the optical-axis symmetrically convex surface on the side of the light source 1 and formed linearly on the deflector 3 by forming the convex surface on the side of the deflector 3 at right angles to the scanning direction. Consequently, the cost is reduced greatly and the adjustment is facilitated. |
