| 摘要 |
<p>1,124,485. Printing process. G. RITZER. FELD. 29 Nov., 1965 [4 Jan., 1965], No. 50556/65. Heading B6C. A method of duplicating on to a copy sheet from a printing master sheet comprises the steps of applying to the image area of the master sheet a coating of a reaction medium suitable for azo dye formation, moistening the coating with an alcoholic solution of a diazonium salt and a coupler which reacts with the salt to form a dye, the chemical reactions between the coating, the salt and the coupler being such that a visible dye is formed on the image area and subsequently applying the copy sheet to the printing master to transfer the dye from the image area thereof to the copy sheet. The copy sheet may be moistened with a neutral liquid e.g. an alcoholic solvent. The image area of the master sheet may be coated with an alkaline substance e.g. triethanolamine or diethanolamine or an acidic substance. The coating may be moistened with an alcoholic solution of a diazonium chloride-zinc chloride double salt of 0-talidine and 1-amino-8-naphthol-4-sulphonic acid.</p> |
