Optical mass memory system using electrophotography

Claim 1

For use in an optical mass memory system, a device for recording digital data, comprising: a source of radiant energy providing a beam of radiant enery; modulator means for modulating said beam in response to said digital data to form at least one ray of radiant energy representing said digital data; electrophotographic imaging means for producing a toned image representing said digital data, the imaging means including an electrophotographic member having substrate means carrying thin film coatings at least one of which is a thin film coating of a photoconductive material less than 1 micron in thickness, and means contiguous to the coating to facilitate uniform charging thereof before exposure, said coating being very dense, wholly inorganic, microcrystalline, the crystals of said coating being generally uniformly oriented vertically relative to the surface of the substrate means, substantially free of effective barrier layers between the crystals, the coating having light transmissivity of at least 70 percent, having a dark resistivity of at least 10 12 ohm-centimeters and a ratio between dark and light resistivity of at least 10 4 and being electrically anisotropic whereby said coating is capable of accepting a rapid charge and retaining same sufficient to enable toning, the imaging means further including charging, imaging, toning and transfer stations located sequentially adjacent said member, the surface of said member being charged at said charging station with a uniform electrical charge, the charged surface then being exposed to said rays at said exposing station to form an electrostatic latent image of discharged elements on the surface of said member, the elements representing said digital data, and the latent image being developed at said toning station with toner particles to result in a toned image that is an optically discernible physical representation of said digital data; a storage medium in the form of a tape of at least partially resinous material, a portion of which is arranged adjacent said electrophotographic member at said transfer station, said transfer station including transfer means for heating and urging said medium against said member to transfer the toned image to the medium with the transferred toned image retaining its representation of the digital data after transfer to said medium; and means for moving said member and medium relative to one another so that said toned image continuously is transferred to fresh portions of said medium and the portions of said member from which said toned image is transferred is reused for forming said toned image.