GB451190A - An improved method of preparing duplicate copies of originals - Google Patents

Abstract

451,190. Printing processes. SZASZ, G., 79, Bernerstrasse, Reinickendorf, Berlin. July 23, 1935, No. 20965. Convention date, July 23, 1934. [Class 100 (ii)] [See also Group XX] Duplicates of documents are produced by preparing a gelatin relief matrix and treating this with a substance which when brought into contact with another substance brings about the production of an organic dyestuff, the paper or other receptive surface being treated with the second substance and the matrix being brought into contact with this or the substance on the matrix being transferred to the receptive surface by a transfer plate or roller. The substances on the two surfaces may be the components of a dye, e.g. an azo dye or the receptive surface may contain a mixture of dye components which are caused to react by the application of the agent on the matrix. Alternatively, a body oxidizable to a dye, e.g. a leuco body may be present in the receptive surface and an oxidant applied by the matrix. Mordants for the dyes may be included in the receptive surface. In examples : (1) the matrix is soaked in a chrome salt and the receptive surface in aniline or an indigo sol ; (2) the matrix carries diazotized p-aminodimethyl aniline rendered acid with acetic acid and the receptive surface phlero-glucinol and potash lye ; (3) diazo and azo components are contained in the receptive surface and the matrix exposed to ammonia vapours. Specifications 341,454 and 384,312 are referred to.