Scanning illuminating device

摘要

This specification discloses a scanning illuminating device in a copying apparatus of the slit exposure type in which a movable slit area of an original is projected upon a movable photosensitive medium by a projection lens. The device is characterized in that light sources are fixed to the opposite end portions of the original surface with respect to the scanning direction, the magnification of the light source image becomes gradually greater at one end of the scanning direction and gradually smaller at the other end of the scanning direction, and imaging elements are moved in the scanning direction so that the illumination distribution on the original surface is formed so as to compensate for the loss of quantity of light of the projection lens due to the so-called cos biquadratic rule or the like to thereby enable copying of uniform density in the scanning direction.