GB801480A - Improvements in or relating to photographic type composing machines - Google Patents

Abstract

801,480. Photographic type-composing. MERGENTHALER LINOTYPE CO. Dec. 22, 1954 [May 27, 1954], No. 37045/54. Class 98(1). A photographic type-composing machine of the kind controlled by a coded tape which has character identification signals based on the binary number system and which is prepared in keyboard operated apparatus having two characters on each key, viz., a shift character and an unshift character interchangeable by a shift key, said two characters having complementary numbers assigned to them, has incorporated therein a font of characters which co-operates with a number of shutters selected by the signals on the tape for exposing the characters singly to a light source, the characters on the font being arranged in a series of intersecting horizontal and vertical rows and in two groups on opposite sides of a vertical median line, one group representing shift characters and the other group representing unshift characters, the corresponding shift and unshift characters being arranged in the same horizontal row and in vertical rows spaced symmetrically on opposite sides of the vertical median line. The arrangement of characters on the font is shown in Fig. 1. The keyboard unit is of the kind described in Specification 754,648 [Group XVI]. As shown in Fig. 2, each character is located within an " em " square 16, the centre of which is indicated at 13, by right hand bearing lines 14 and base lines 15. The selected character is illuminated by a light source 20, Fig. 3, by means of the selection system described in Specification 801,481. The light from, the selected character passes through an intermediate lens (not shown), an imaging lens 21, lenses 22, 23 which are adjustable to vary the point size of the projected image, and then, after reflection at a mirror 24, passes through a projection lens 25 to form an image on the film 26. For text composition the mirror 24 is moved step-wise to space the projected characters until the movement of the mirror carriage 27, as measured by a grid plate 28 which is carried past and continually interrupts a light beam to a photoelectric cell 29, is equal to the character width as indicated by the marks below the line 15, as described in the Specifications referred to above. As shown in Fig. 5, the plate 28 carries a series of marks . of progressively greater spacing corresponding to different point sizes of projected character. The photoelectric cell 29 can be moved so that the beam of light falling upon it is intersected by any chosen series of marks according to the desired point size.