Abstract: An improved optical printing head is described including a linear array of light sources, and a lens array comprised of graded index optical fibers arranged in a hexagonal close-packed array, there being at least three rows of individual fiber lenses. The linear array of light sources is aligned with, and parallel to, lines of symmetry of the graded index lens array, where the lines of symmetry are defined as lines along said graded index lens array which will transmit a line of light incident thereon with a minimum deviation in the intensity of light transmitted through the lens array. A photosensitive surface on a rotating drum is provided onto which light images from the optical printhead are incident. The print head can be used in optical printing machines.