GB246661A - Improvements in or relating to the duplication of printing surfaces, sign plates andthe like by etching - Google Patents

Abstract

246,661. Baker, J. Jan. 23, 1925. Etching transfering designs; transfers.-In a process for duplicating printing - surfaces, sign plates, &c. by etching, the resist is applied to the plate to be etched by a series of transfer impressions taken from the original in a resist ink. By superposing a number of impressions, the etching may be carried out without further strengthening of the resist. The etching may be performed in stages, one or more transfers being applied before each stage, and the transfers after the first etching may have their inked portions spread beyond the boundaries of a normally prepared transfer so that the characters are produced with widened bases. The transfer paper 3, Figs. 3 and 6, is stretched on a frame 4 provided with holes 5 adapted to register with pins 6 on the chase 1 containing the original, and also with pins 9, Fig. 4, on a board 8 on which the plate 11 to be etched is mounted. The plate 11 is provided with holes to engage pins 10 on the board 8 so that the plate can be accurately positioned between each etching operation. The holes 5 and pins 6 are located at opposite corners of the frame and chase respectively so that by positioning the original to one side of the chase and turning the frame through an angle of 180‹, two impressions may be taken on a single transfer sheet. By employing a square frame, four impressions may be taken on a single sheet. The inner portions 12 of the pins 6 are of a reduced diameter so that, by engaging the holes 5 with these portions of the pine, a limited lateral movement of the frame over the chase mav be obtained. In operation, an impression is taken on a sheet 3 by engaging the holes 5 with the larger portions of the pins 6 and the impression transferred to the plate 11. This operation is repeated until the resist on the plane 11 is of the desired thickness and the plate is then etched in the usual way. If characters with widened bases are desired, the plate is etched after receiving one or more transfers as described above. The plate is then replaced on the board 8 to receive further transfers prior to a second etching operation. These transfers are prepared with widened inked portions by engaging the frame 4 with the portions 12 of the pins 6 and moving the frame laterally to smear the paper 3 over the inked original, or by applying excess ink to the original, taking a normal transfer, dusting the impression with resin and applying pressure by means of a wad or wool or other suitable material. The transferring and etching operations may be repeated, the inked portions of the transfers being progressively widened by replacing the pins 6 by others having reduced portions 12 of progressively smaller diameter. Characters with widened bases can also be prepared by employing transfers with inked portions of progressively reduced width, the ink being removed from the plate after each etching operation.