Patent GB-823005-A (GB)
Title: Improvements relating to photographical type-composing machines
IPC: B41B27/28
Filed: 1957-11-01
Abstract: 823,005. Photographic type-composing. MERGENTHALER LINOTYPE CO. Nov. 1, 1957 [Nov. 23, 1956], No. 34226/57. Class 98(1) A tape-controlled photographic typecomposing machine of the kind described in Specification 801,481, having an adjustable optical system for changing the size of the type image formed on the photographic material, includes automatic means responsive to a code signal on the tape for adjusting the measuring device correspondingly and simultaneously in order to vary the speed of relative movement between the photographic material and the optical system so that the interval between successive energizations of the flash lamp is constant.  General arrangement. As shown in Fig. 1, the light source 20, together with a reflector 22 and a condenser system 24, is mounted in a housing 21, and illuminates a font plate 23 followed by a shutter 25 and a lenslet array 26. Light from a character uncovered by the shutter is collimated by the corresponding lenslet, and an image is formed by a lens 27 on its optical axis. The light then passes through an eyepiece lens 31, is collimated by a second eyepiece lens 32, and is reflected by a mirror 33 to be imaged by a lens 34 on to a photographic film. The eyepiece lenses, the mirror and the projection lens are mounted on carriages slidable along rods 43, 44 mounted in brackets 45, 46 on the bedplate 47 of the machine. Eyepiece lenses. As shown in Fig. 5, the eyepiece lens 31 is mounted in a holder 50 mounted on a carriage 57 with sleeves 60, 61 slidable on rods 43, 44. The carriage is driven by a reversible motor 67  through a rack 63. The motor also drives a gear wheel 74 mounted on a shaft 75 which drives a commutator mechanism 77 forming part of the control circuit of the machine. The carriage also carries a detent plate 83 (see also Fig. 6), having notches 84 to be engaged by a roller 87 on a spring-loaded arm 90. The other eyepiece lens 32 is similarly mounted on a slidable carriage, and the positions to which the lenses are moved are controlled by signals from the tape in accordance with the point size of characters required. Grid plate. Shaft 75 also drives, through bevel gears 81, 82 and a universal joint 127, a shaft 126, which in turn drives a shaft 131 (Fig. 7), through another universal joint 130. Shaft 131 is journalled in blocks 132 on a channel member 133, and has keyed thereto pinions 134 which engage racks 137 movable in grooves 136 in member 133. The racks are joined at the top by a channel member 140 engaging a roller 142 on a frame 143 slidable on a vertical rod 145 carried by the carriage 41 of the projection lens 34. The frame 143 carries a grid plate 42 of the kind described in Specification 801,481, but the rows of markings 147, instead of being evenly spaced, are arranged so that, when a change-of-point-size signal is received and motor 67 is energized, the resulting movement of the frame 143 brings the appropriate row 147 into alignment with a photo-electric cell. Projection lens and mirror. As shown in Fig. 11, the projection lens 34 is mounted on. a carriage 41 which slides on rods 43, 44, and which also carries a filter 40 through which light passes before being deviated through 90 degrees by the mirror 33 (Fig. 1) to the lens 34. The carriage engages a lead srew 55, driven by a reversible A.C. motor '52 of the variable speed type, the speed being controlled by the point size'' signals on the tape so that the displacement of the carriage is proportional to the size of the characters. An electrically operated band brake 162 arrests the carriage at its extreme positions or elsewhere when motor 52 is deenergized. Speed control of the motor is effected by switching various resistances into and out of a thyratron circuit by means controlled by the tape signals. Lamp intensity. The correct exposure of the photographic film on which character images are formed is maintained by varying the intensity of the flash emitted by light source 20. The light source is energized by the discharge of a condenser therethrough as described in Specification 801,481 and condensers of varying capacity are switched in and out of the circuit by means controlled by the tape signals.