Abstract: An intermediate transfer drum is employed and a photosensitive belt having a length equal to the outer peripheral length of the intermediate transfer drum is arranged with a vertical orientation. Developing units of the same shape are arranged on one side of the photosensitive belt, and a charging unit and a cleaner are arranged on the other side. The intermediate transfer drum is placed under or diagonally under the photosensitive belt. A transfer mechanism for transferring an image on the intermediate transfer drum to a sheet of paper is placed under or diagonally under the intermediate transfer drum. By this arrangement and construction, a small-size color electro-photographic apparatus having a size capable of easy use as a desk-top apparatus is provided, which satisfies quality of image, speed of printing, and easiness of maintenance requirements at the same time.

Abstract: A small and inexpensive optical scanning apparatus is attained by an optical block 1 disposed between a rotating mirror 2 and a photosensitive body 3 and having specular surfaces formed at part of inner side of surface so that light from the rotating mirror 2 is reflected within the optical block 1 plural times back and forth and reaches the photosensitive body 3 in order to correct the curvature of field, the distortion aberration and the inclination of surface in an optical scanning system. The length of the optical path within the optical block including reflection is set to 60% or more of the whole length of optical path from the rotating mirror 2 to the photosensitive body 3. The surface of the optical block 1 on the side of the photosensitive body is formed into a curved surface to constitute a concave mirror. The rotating mirror and the photosensitive body are arranged in optically conjugate relation in sub-scanning direction by the focal distance.