GB191117772A - Improved Method of Copying Documents, Drawings and the like. - Google Patents

Abstract

17,772. Hurwitz & Co., H. Aug. 5, 1910, [Convention date]. Copying documents; printing processes; printing-surfaces. - Letters, drawings, &c. to be copied are written or drawn with an ammoniacal ink, for instance one containing gallic acid, sulphate or chloride of iron, or both, gum arabic, ammonia, and water. The document is pressed against a glass, porcelain, enamel, or like roller or plate, which is previously coated with a solution containing grape sugar and alum, the preferred solution consisting of grape sugar, alum, hydrochloric acid, magnesium chloride, and water. The composition with the design on it is then treated with a solution of boracic acid in glycerine in order to render the blank parts insensible to the subsequent inking, which takes place before prints are obtained. The grape - sugar composition referred to may be used for cleaning an old design off. Instead of using an ammoniacal ink as described, a dried ink may be applied to a design &c. produced in ordinary ink. The process may be carried out by the apparatus shown in Fig. 3, in which a glass sheet a mounted on a resilient cushion f is supported by a bed r with bevelled edges c. The grape-sugar solution is applied to the sheet a, and when set, a letter &c. is placed on the bed and pressure is applied thereto by a pad g on a cover k pressed by means of springs i on to the letter, the pressure being applied for from a half to eight minutes according to the nature of the document. To store the plate a, it is placed with its coated side downwards, and with its edges resting on the edges c.