Optical mass memory system using electrophotography

Abstract

An electrostatic image of binary data representing elements is formed on a particular electrophotographic member disclosed and claimed in U.S. Pat. No. 4,025,339. The electrostatic image is toned and the toned image is transferred to a storage medium. The storage medium is in the form of an extended length of dual-layer transparent synthetic resin material. One of the layers has a softening range of temperature less than the substrate. At the transfer, the one layer is heated and the toned image is pressed into the one layer. The storage medium carrying the toned image then is wound up on a storage or take-up spool while fresh medium is fed from a supply spool. The two spools are carried by a housing and the housing, spools and medium form an optical mass memory cassette. Reading of the data occurs by deflecting rays of light across the medium and the light that is transmitted through and blocked by the medium is sensed in bar sensors, one for each ray. The rays are deflected across the medium in a pattern similar to the pattern used for imaging the electrophotographic member. The electrical signals from the sensors are used to produce binary data representing the data stored on the medium. The data stored in the optical memory cassette is unaffected by magnetic and electric fields and light energy, a tremendous quantity of data can be stored on a relatively small length of storage medium, and the storage medium is inexpensive so that it may be discarded when the data is obsolete.