| 摘要 |
943,455. Electrophotographic production of printing plates. KALLE A. G. March 16, 1962 [March 23, 1961], No. 10230/62. Headings G2H and G2M. [Also in Division H1] An otherwise known electrophotographic process uses a material comprising a support consisting of metal or having a metal surface, and a photoconductive insulating oxide layer produced by anodisation of the metal. Any metal may be used which is susceptible to anodisation but aluminium, tantalum, and titanium are preferred. The properties of the oxide film may be modified during or after its formation. The material is charged and exposed in known manner and developed in a standard way e.g. with a carrier/toner mixture and the powder image either fixed or transferred to another surface. To make a printing plate from e.g. an aluminium foil with superficial oxide film bearing a fixed resin image the exposed oxide is made hydrophilic by wiping with aqueous phosphoric acid and the plate used directly in an offset printing machine. After use the resin coating may be removed by treatment with ethylene glycol monomethyl ether and the foil can then be used again to make a new printing plate. |
