Improvements in printing processes

摘要

344,431. Printing processes ; paper. JEANNIN, R., BOUILLON, J., and BOUILLON, C., 32, Boulevard de Grenelle, Paris. Dec. 4, 1929, No. 37225. Convention date, Dec. 13, 1928. [Class 100 (ii).] A printing process, in which no greasy constituents are used and which permits easy recovery of the printed paper, consists in printing with a substance which reacts chemically with a material incorporated in or coating the paper. The paper is coated or impregnated preferably with an inorganic salt or the salt is added to the pulp during manufacture. In an example, copper or iron sulphate, or a mixture of the two, is added to the pulp, and printing is effected with a solution of sodium sulphide together with an accelerator such as soda and sodium ricinoleate. After repulping, the precipitated sulphide can be removed by treating with dilute hydrochloric acid. Reference has been directed by the Comptroller to Specifications 4905/83, [Class 96, Paper &c.], 13000/96, [Class 101, Printing, other than letterpress &c.], and 24560/97, [Class 146, Writing instruments &c.].