| 摘要 |
PURPOSE:To obviate the degradation of images even when the width of an exposure slit is expanded by providing sheet glass within the range of the width smaller than half the slit width in parallel with the exposure slit on both sides in a longitudinal direction in the opening part of the slit. CONSTITUTION:This invention relates to an exposure optical system of correcting tracking errors by inserting sheet glass 4 of a thickness (d) between a projecting lens and a photosensitive drum 3 perpendicularly to the optical axis (z) of the lens, wherein the glass 4 is disposed symmetrically with respect to the axis (z) at such a spacing at which the width in the opening part 2a of an exposure slit 2 is smaller than half the width W of the slit. Then the expansion of the width W of the slit 2 from W2 to W1 is possible and the quantity of light (integrated value) on the drum 3 is increased without degrading images. |
