Patent GB-679930-A (GB)
Title: Improvements in or relating to the photographic reproduction of printing plates or the like for use in the reproduction of music in printed form
IPC: B41B17/02
Filed: 1949-11-29
Abstract: 679,930. Photographic type - composing. KARLQUIST, B. F. Nov. 29, 1949 [June 2, 1949], No. 30574/49. Classes 98 (i) and 98 (ii). [Also in Group XXXVII]. A method of producing printing surfaces for use in the production of music in printed form comprises successively photographing on a recording element individual notes or like musical signs which are provided on a carrier therefor, each note being positioned for projection on the recording element by relative displacement of the carrier and recording element, an image of each note being projected simultaneously on to the recording element and on to a viewing device for checking the correct positioning of the notes, and using the photographic recording element for the production of the pringing surface. Apparatus for carrying out the method comprises a note carrier, a recording element carrier and a viewing device, mechanism which effects displacement of the note carrier in its plane of movement with respect to the recording element carrier and the viewing device in two mutually perpendicular directions, and means adapted to project images of notes on the note carrier on to a recording element and simultaneously on to the viewing device. As shown, Fig. 2, two angle strips 1, 2 are supported by the framework of the apparatus. A framework comprising angle strips 3, 4 joined by bars 11, 12 has wheels 5, 6 running on strips 1, 2, the movement being effected by threaded rods 9, 10 journalled in brackets on strips 1, 2 and engaging nuts 7, 8 carried by strips 3, 4. Rods 9, 10 are rotatable by a servomotor controlled from a main control panel. A carriage 13 has wheels 14, 141 by which it travels on rod 11, 12 under action of a cord or wire 18 passing over pulleys 16, 17, pulley 16 being driven by a wheel 15 driven by a servomotor controlled from the main panel. Carriage 13 has rods 19, 20 on which travels a carriage comprising spaced plates 30, 32, Fig. 5, in which is journalled a shaft 31 carrying discs 33, 34 bearing musical notes and signs. An arm 22, Fig. 2, is pivoted at 21 to carriage 13. The shaft 31 passes through a slot 61 in arm 22 and a slot 64 in carriage 13, so that when arm 22 is rocked the disc assembly moves along rods 19, 20. A segment 24 at one end of arm 22 engages a wheel 23, driven by an electric motor. The motor is controlled to move the carriage into a number of positions selected by a set of keys (see Group XXXVIII). A similar mechanism rotates the discs 33, 34 to select the signs. A printing lamp between the discs illuminates a selected sign on disc 34 for projection on to a photographic sheet, and also illuminates a similar sign on disc 33 for projection on to a sheet of sensitized material of a kind which discolours on exposure, to provide a test sheet. Such a sheet may comprise a photographic plate with a silver bromide emulsion, treated with citric acid and silver nitrate. When fresh sheets have been inserted for printing, strips 3, 4 and carriage 13 are brought into position for projection on to the top left-hand corner of the sheet. A sign on the discs is selected representing five points of light; the lamp is switched on and carriage 13 traversed to record the five stave lines. The carriage 13 is returned, and the various signs and notes required are recorded in turn, carriage 13 being moved to space the signs. The position of notes on the stave lines is selected by a set of keys by which arm 22 is moved to a selected position, and moves the whole character disc assembly with respect to the stave lines. After recording a line of music, lines between bars are produced by moving carriage 13 to the required position, projecting a point of light on to the sheet from disc 34, and moving the whole assembly along guides 1, 2. The sheet bearing the record is developed and used to produce a photomechanical printing plate.