| 摘要 |
<p>PURPOSE:To perform exposure at a high speed even when a light source small in quantity of light is used by a method wherein the luminous fluxes from respective light emitting pattern rows are controlled in synchronous relation with the movement of an object to be exposed so as to be superposed at the same place to expose said object. CONSTITUTION:A printer head is equipped with an LED array 1 having three light emitter rows of (n) lines and the luminous flux emitted from the LED array 1 is formed into an image on a photosensitive drum 3 being an object to be exposed through the lens array 2 of image forming lenses. Luminous fluxes are emitted in the same pattern from the respective first - third light emitter rows (a)-(c) of the LED array 1 in this order so as to follow the rotation of the photosensitive drum 3. The rotation speed of the photosensitive drum 3 and light emitting timings are determined so that the same patterns formed by the luminous fluxes from the respective light emitter rows are superposed on the photosensitive drum 3 at the same position. Therefore, the same linear pattern is superposed three times to expose the region of one line of the photosensitive drum 3. By this method, necessary quantity of light is obtained even when the emitting quantity per one row is low or the rotational speed of the photosensitive drum is fast.</p> |
