GB237090A - Improvements in and relating to duplicating - Google Patents

Abstract

237,090. Gestetner, D. July 11, 1924. Stencils and stencilling. - In duplicating by means of flexible stencil sheets adapted to be stencilized by pressure or produced by photographic means, a sheet provided at intervals with ink-resisting elements is arranged behind or in front of the stencil in order to economize ink and prevent it from spreading unduly. The sheet may consist of felted or woven filaments, constituted. e.g. by Yoshino paper or finely-woven lawn, and the ink-resisting elements may be arranged in lines, dots, reticulations, &c. A sheet so prepared may be associated with a stencil or it may be combined with a stencil or a sheet adapted to be stencilized by pressure. In preparing the poroussheet, it may be coated with a light sensitive coating, printed behind a lined, dotted, or reticulated transparency and finally treated to remove the parts not acted on by light. By a second method. a lined &c. image may be formed on a pellicle of bichromated gelatine on a backing from which it is transferred to a support for development, it being thereafter transferred to the porous sheet. According to a third method, engraved rollers areused to print on the porous sheet in an ink-resisting material. In a combination stencil sheet including a sheet adapted to be stencilized by pressure and a porous sheet having lines &c. thereon, the two sheets may be secured together and to a backing or protective sheet. Alternatively, the porous sheet may be coated with a composition adapted to be stencilized by pressure, or with a gelatinizing organic colloid and a tempering- agent. With a stencil so prepared, a second porous sheet provided with lines &c. may be employed, or such a sheet may be used with a stencil prepared according to Specification 148,626. The Yoshino paper used in preparing the porous sheet may be strengthened by lightly sizing it with a water-insoluble glaze.