| 摘要 |
1,136,029. Printing plates; electrostatic printing. RANK XEROX Ltd. 20 May, 1966 [24 May, 1965], No.22612/66. Heading B6C. A printing plate is manufactured by depositing a frostable composition in image configuration upon a substantially non-frostable substrate and frosting said composition. The substrate may comprise a dielectric material such as sheet polyethylene terephthalate or glass or metal or a zinc oxide paper or a zinc oxide coated upon a metallic plate. The frostable composition may be any one of the particulate compositions disclosed in Specification 1,049,881. In particular rosin esters may be used or a copolymer made from alpha-methylstyrene, or a poly styrene composition. In described embodiment the xerographic process is used with the particulate. composition as the developer tower. The developed image is transferred to thermoplastic sheet material and fixed by simultaneously applying heat and a corona discharge. This fixing treatment " frosts " the image areas such that the fused particulate composition becomes sponge like and receptive to ink. Other described forms of imaging the substrate are stencilling, free-hand deposition and vapour thermography. The heating step of the fixing treatment may be replaced in suitable -cases by solvent action from the vapours of trichloroethane. The frosted image may be formed directly on a cylinder surface. |
