Abstract: An optical storage medium in which the effect of optical interference is utilized to provide information storage. Heating of selected portions of the optical storage medium causes a permanent change in the wavelength and intensity of the interference fringes of the optical storage medium, and those changes give rise to large changes in light reflectivity at the initial interference fringe wavelengths, and hence gives rise to an optical pattern that is readily detectable. Preferred storage medium materials include alloys of the Ge-Se-S-Te group overlaying a metallic layer.

Abstract: A method for the preparation of X-form metal-free phthalocyanine and X-form metal-free compounds which comprises heating any metal-free phthalocyanine polymorph or compound to from about 540.degree. to about 580.degree. C and cooling the resulting product formed thereby is herein disclosed.

Abstract: An apparatus and method for electrostatic copying in which the original document is transported on a conductive grounded plate to several processing stations. The document is positioned with its image or front side on the surface of the plate. At a charging station, the back side of the document receives a uniform electrostatic charge which, in the image regions, leaks off through the plate to provide a latent electrostatic image. The document is then transported to a developing station for development of the latent image with toner and then to a transfer station where the toner is transferred to a final support material and fused to such material. Residual toner is then removed at a cleaning station.

Abstract: A method for the preparation of X-form metal phthalocyanine and X-form metal-free compounds which comprises heating any suitable metal phthalocyanine polymorph or compound to from about 600.degree. to about 650.degree. and cooling the resulting product formed thereby is herein disclosed.