Patent GB-1268583-A (GB)
Title: A photosetting method and machine
IPC: B41B17/06
Filed: 1970-02-27
Abstract: 1,268,583. Photographic type-composing apparatus. H. BERTHOLD MESSINGLINIENFABRIK UND SCHRIFTGIESSEREI A.G. 27 Feb., 1970 [8 April, 1969], No. 9694/70. Heading B6W. Associated with each symbol 1 on a matrix carrier 2, there is a mark 3 representing the spacing appropriate to the symbol. The matrix carrier 2 is held stationary during the exposure of a selected character. Each mark 3 is sensed during this exposure, whereupon the sensed spacing is stored temporarily, until immediately after the exposure, when the spacing movement is effected in accordance with the stored spacing. In the apparatus (Fig. 3), the light path extends from lamp 4 to the photosensitive material via a condenser 5, an electromagnetic shutter (not illustrated), the symbol object on the matrix 1, a prism (44), reversing prism (45), lens (46), reversing prism (47) and prism (48). A uniformly graduated knob 26, Fig. 1 and (Fig. 3) is provided for moving support 25 via rack and pinion 28, 27, for adjusting the image size. The support 25 and a further support 40 carry prisms (47) and (45) respectively, are slidably mounted on guide rail (38), and are interconnected by linkage (41) with a stationary support (39) for prisms (44, 48) and lens (46). The photosensitive material is supported on a drum (49), journalled in a carrier (50) for axial movement along a slide (51) under the action of a lead screw (53) for line spacing. Rotation of the drum (49) for character spacing is effected by a stepping motor (56) through a splined shaft (55) meshing with a gear (54) fast with the drum. During illumination of a selected symbol 1, a rocker plate 15 incorporating a knife edge 16 is rocked at a predetermined rate by a continuously rotating synchronous motor 10, via an electromagnetic clutch 11, shaft 12, pinion 13, and toothed sector fast with plate 15. A mirror 7 is thereby pivoted at an angular rate dependent on the setting of knob 26, to cause phototransducer 9 to provide an output pulse. The time elapsing before the provision of an output pulse is a measure of the symbol spacing as represented by the mark 3. Varying the image size with knob 26 automatically varies this time and hence the character spacing, since a coupling pin 17 is moved by the support 25 and link 18 along a knife edge 16 on the plate 15, thereby varying the effective lever arm for pivoting the mirror 7. The elapsed time is measured by transparent disc 22 with uniform markings 23 scanned by a photosensitive transducer 24 to generate an electrical pulse train. This pulse train is terminated when transducer 9 emits a pulse, the number of pulses in the train representing the character spacing. The pulses are recorded in digital form in a register (31, Fig. 2) and stored temporarily in a second register (32). After exposure and during the subsequent rotation of the character disc 2 to select the next symbol, the value stored in the second register (32) is used to control the step motor (56). A stop pin 20 carried by worm wheel 21 is set by rotation of a knob 29 so that the initial position of arm 19 fixed to shaft 12, and hence the mirror 7, can be adjusted to set the spacing between each composed character by a predetermined constant amount.