IMAGE FORMING OPTICAL APPARATUS

摘要

PURPOSE:To perform high grade printing by setting the lens diameters of respective fine lenses to different values to equalize the brightness per a unit area on a photosensitive surface of each original picture pattern. CONSTITUTION:The lens diameters of the fine lenses 3A constituting a lens array 3 are respectively different and the lens diameter of each of the fine lenses 3A present in the vicinity of the center of the lens array 3 is set so as to become smaller than that of each of the outside fine lenses. The set values of the respective lens diameters are determined on the basis of the diameter of a photosensitive drum, the angle of inclination of main beam and spec of each part so as to make the luminosity of each image constant. The lens array 3 is constituted by arranging and fixing the fine lenses 3A on the same plane unidimensionally or two-dimensionally at appropriate intervals and a flat plate microlens, wherein a large number of almost semispherical fine lens parts gradually reduced in refractivity from the center toward the outside are integrally formed to a transparent substrate composed of glass or plastic by diffusing a substance increasing the refractivity of the substrate from a large number of the points on the surface of the substrate, is pref. By this method, the character corresponding to each light source can be formed into an image in the same photosensitive quantity.