Patent GB-544882-A (GB)
Title: Improved process and apparatus for developing blue prints and diazotype prints
IPC: G03C5/18
Filed: 1940-01-18
Abstract: 544,882. Photographic developing apparatus; diazotype and blue-print processes. NAAMLOOZE VENNOOTSCHAP CHEMISCHE FABRIEK L. VAN DER GRINTEN. Jan. 18, 1940, No. 1144. Convention date, Jan. 19, 1939. [Class 98 (ii)] Developing or fixing fluids are coated upon sheets, e.g. of paper, metallized paper, metal foil, cellulose compounds &c. by passing these over a non-soft and non-porous member which leads the fluid in a multiplicity of minute uninterrupted parallel or other non-intercommunicating canals to the place where the sheets leave the member, the streams being so close together that the fluid is coated uniformly. The sheet 4, Fig. 1 may be guided by rollers 5 over the upper surface of a roller 1 which has a system of minute circular grooves, or a continuous helical groove formed by engraving or by winding wires on its periphery, and which is partially immersed in a bath 3 of the coating fluid. The rollers 1 may be fixed or rotatable either way according to the coating weight desired, and this may also be varied by varying the number, cross-sectional area, and pitch of the grooves within limits which are discussed in the Specification, or by varying the speed of the sheet, or by adjusting the surface level of the fluid in the bath 3, by raising or lowering a vessel 6 connected by a flexible tube 7. The roller may be replaced by a comb 11, Fig. 6, which feeds the fluid along the minute ducts 13; or by minute tubes placed in one or more rows. Also, instead of partially immersing the roller 1 in the fluid, it may be supplied with liquid from the bath via one or more intermediate rollers. Edge-wiping means, a blotting roller, or a coupled drying device may be provided to operate on the sheet after coating. The material of the roller &c. may be metal which may be plated as with chromium, or stainless steel, glass, synthetic resin, or hard rubber. The apparatus is free, to a greater or less extent discussed in the Specification, from the " starter" " disadvantage of known forms of apparatus, i.e. the failure in the initial coating stage to apply the requisite quantity of fluid, and this is illustrated in numerous examples for each of which the appropriate construction of roller &c. is discussed. These include (1) coating a paper sheet with a solution of para diazo-N- ethyl:N-benzyl aniline chloride, thiourea, oxalic acid and gelatin, exposing, and developing with a solution of phloroglucinol, resorcinol, thiourea, sodium thiosulphate, soda, borax, and the sodium salt of isopropyl naphthalene sulphonic acid with or without glycol mono butyl ethers; (2) coating with a solution of para diazo N:N diethyl aniline chlorstannate, tartaric acid, boric acid, thiourea and phloroglucinol and developing with a solution of soda, sodium thiosulphate, and the sodium salt of isopropyl naphthalene sulphonic acid, or with liq, ammonia; (3) coating with a solution of 1-diazo-4 benzoylamino-2:5 diethoxybenzene chlorostannate, citric acid, and boric acid, and developing with a solution of phloroglucinol, the sodium salt of isopropyl naphthaline sulphonic acid, and either soda and borax or sodium acetate; (4) coating with a solution of ferric ammonium oxalate, potassium ferricyanide, secondary sodium phosphate and gelatin, exposing, and fixing with a solution of primary ammonium phosphate, phosphoric acid, zinc sulphate, ammonium persulphate and the sodium salt of the sulphuric acid ester of oleic acid butyl ester; (5) coating with a solution of para-diazo- N-ethyl:N-benzyl aniline chloride, thiourea, oxalic acid, and gelatin, exposing, dusting on a powder containing soda and phloroglucinol, and then developing by applying water; (6) saponifying on one side an acetyl cellulose film and coating this side with a solution of para-diazo- N-ethyl:N-benzyl aniline chloride and tartaric acid, printing thereupon directly or by the reflex method, pasting the film if thin on paper by means of casein in diluted latex and developing with the developer in (1) above. Specifications 295,993, 326,568, [both in Class 98 (ii)], 416,489 and 538,863, [Group VIII], are referred to. The Specification as open to inspection under Sect. 91 refers also (1) to the coating of sensitive layers in a similar way, and gives an example in which a matt aluminium sheet, pasted on paper, is coated with a solution of potassium bichromate and gum arabic and then treated to produce an offset printing surface such as is used for office duplicating machines; and (2) to a construction of the liquid-applying member by which the liquid is applied in a sheet from a flat tube terminating in a slit. This subjectmatter does not appear in the Specification as accepted.