| 摘要 |
PURPOSE:To reduce a pitch between scanning lines by simple and small-sized constitution, by constituting so that a pitch between plural laser luminous fluxes is reduced by use of a prism. CONSTITUTION:Luminous fluxes L1-L4 emitted from plural semiconductor lasers 1 which are arrayed linearly at constant intervals are set to parallel luminous fluxes by spherical lenses 3, 4, pass through a triangular prism 5, and a pitch between the luminous fluxes is reduced. Said parallel luminous fluxes pass through 2 cylindrical lenses 6, 7, are deflected by a rotary polyhedral mirror 8, and are allowed to form an image on the surface of a photosensitive drum 10 through an image formation lens 9. Since it is unnecessary to make the rotary polyhedral mirror 8 large-sized, a pitch between the scanning lines is reduced by simple and small-sized constitution. |
