Patent GB-671660-A (GB)
Title: Improvements in or relating to typographical photo-composing machines
IPC: B41B19/04
Filed: 1946-10-20
Abstract: 671,660. Photo-composing machines using scanning processes. MERGENTHALER LINOTYPE CO. Oct. 20, 1948 [March 23, 1948], No. 27252/48. Class 40 (iii). An arrangement included in, or associated with, a typographical photo-composing machine comprises the combination of a first cathoderay tube having a screen provided with a series of characters which can be individually scanned by shifting the beam to predetermined positions, a second cathode-ray tube creating images of the selected characters scanned and means for photographing these images. As shown in Fig. 1, the arrangement comprises two cathode-ray tubes 11, 12 of which the screens 11a, 12a carry the patterns of the characters in two different printing types. The actuation of a key 21 operates a relay 22 which at contact 22b connects the tube 12 to the amplifier 23. The actuation of a key 10, corresponding to the character to be scanned and reproduced, effects the operation of a relay arrangement 20 which disconnects a cut-off voltage from the control electrodes of the cathode-ray tube 11 or 12 and of the reproducing tube 13. The scanning generators 16, 17 and 18, 19 of the " transmitter " and " receiver " tubes respectively are fed from a common oscillator 15 and are adjustable to vary the shape and size of the respective scanned rasters. The actual scanned area of the mosaic 11a or 12a is controlled in accordance with the actuated key by means of sets of resistances 34, 35 which are selectively introduced into the circuits of the horizontal and vertical scanning coils H, V of the tubes 11, 12. The impulses derived from the character scanned are utilized to produce the corresponding image on the screen 13a of the cathode-ray tube 13. The image is projected by a lens 14 on to a film 24 held between a pressure roller 26 and a driving roller 25 carried on the shaft 27 of a ratchet 75 actuated by a pawl 74 connected to a pivoted arm 72 operated by a relay 71 connected in a self-interrupting circuit comprising a contact member 70. The stepping movement of the ratchet and the feed of the film between the recorded characters is determined by an arm 78 rotated by the shaft 27 over a bank of contacts 69, one of which is selectively marked by a two-position switch member 36 comprising an arm moving over horizontal and vertical banks of contacts. The operation of the member 36 is controlled by two sets of switch members selectively controlled by the actuated key, which effectively marks selected contacts on separate banks 40, 42 over which are stepped arms 51, 56 on the shafts of ratchet wheels 48, 62, the latter being moved by pawls 47, 61 operated by relays 44, 60 connected in self-interrupting circuits comprising contact banks 39, 41 and arms 50, 55 which provide the driving circuits until the arms 51, 56 reach their respective marked contacts. The marked contact of the member 36, indicated diagrammatically in Fig. 3, determines the spacing to be applied, and for characters having equal spacing, the corresponding contacts of the member 36 are wired together. For the spacing between words, the actuation of the spacer key causes the tube 11 or 12 to scan a blank and the operation of the switch arms 51, 56 and contact banks 40, 42 is such that the selected contact of the member 36 marks a contact of the bank 69 to effect a predetermined feed of the tape 24. Different predetermined spacings may be selectively employed by the provision of two separate spacer keys. The circuits may at any time be restored to normal by a key 81 which opens the locking circuits of relays 28, 29 which are operated by the depression of the character or spacing keys. In a modified system, Fig. 2 (not shown), the depression of a key moves the scanning beam of the transmitter tube to the edge of the area occupied by the character to be transmitted, a scanning circuit being provided to produce deflection of the beam in one plane, e.g. the vertical direction only. At the receiver the linear image formed on the screen of the cathode-ray tube is focused on to a film carried on a rotating drum which provides the second scanning component and, by its rotation, controls a rotary potentiometer device which provides a stepped voltage for effecting the horizontal disposition of the beam during its successive vertical scanning transversals. When the scanning beam reaches the final portion of the character being transmitted it impinges on a part outside the confines of the actual character and transmits an impulse which forms on the screen of the receiving cathode-ray tube a bright spot which is reflected by a mirror to a photo-electric cell controlling a relay which, on operation, restores the apparatus to the normal non-operative position. In this arrangement the spacing between letters is automatically controlled by the markings indicating the confines of the letter or character, and the spacing between words is effected by a key which effects rotation of the motor of the receiver and the scanning of a blank space apart from the stop mark from which an impulse is derived to stop the motor at the receiver. Spacing between lines is effected by a small motor rotating a worm and worm-wheel through which passes a threaded shaft carried by the framework of the drumthe period during which the drum rotates being determined by a delay-action relay operated by an assigned spacer key.