Patent GB-1208754-A (GB)
Title: Typesetting system and character generating apparatus for use therein
IPC: B41B27/28
Filed: 1967-10-10
Abstract: 1,208,754. Photographic type-composing. HARRIS-INTERTYPE CORP. 10 Oct., 1967 [3 Nov., 1966], No. 46330/67. Heading B6W. Photographic type-composing apparatus comprises a cathode ray tube having means to deflect the beam of the tube along two perpendicular co-ordinate axes in a raster pattern to form each character, and control circuitry providing reference signals which compensate for non-linearity in the tube characteristics and allow a character to be displayed with consistent size and intensity at any position along the horizontal co-ordinate of the tube. The typecomposing apparatus includes a character generator member having all the information required for producing a character stored in digital form. Production of character - generator member.- Each basic character or symbol (10) is placed on an analysing grid (11), and is digitized to conform to the blocks of a graph, either manually or by means of a computer (Figs. 1 and 2, not shown). The digitized character is placed on a drum (16) and is scanned by a photo-cell (17), both the drum and the photo-cell being moved in small incremental steps in a raster pattern; the output of the photo-cell is amplified and led to a tape-punching machine (28) to provide a paper-tape (27) having punch-holes in a particular patterns representing character signals. End-of-character and other reference signals are also punched in the tape (Fig. 4, not shown). The character generator member 41, Fig. 6, is provided with a plurality of bands extending circumferentially, each band comprising a plurality of tracks containing character and control information in digitized form (Figs. 1 and 5, not shown). The member 41 is a photographic plate which is exposed by glow modulator tubes 60 focused by lenses 61 on to fibre optic transmitters 62; the glow modulator tubes 60 are selectively energized from reader registers 80 by means including a master synchronizing disc 45 which produces timed pulses in the circuit. Each glow modulator applies a single track to the disc 41, and a correction system 84 (Fig. 7, not shown), controls the tape advance mechanism in synchronization with the pulses from disc 45. General arrangement of photographic type composing machine.-A coded control tape 110, Fig. 10 (also Fig. 9, not shown) is read by reader 111 and the output is channelled to buffer storage 112. The buffer storage releases blocks of information to decoder 113, which provides outputs to a character generator 114, a leading control 117 and a horizontal control circuit 116. The outputs of circuits 114 and 116 are applied to cathode-ray tube 115 and individual lines of composition on the face of the tube are focused by lens 120 on to photosensitive material 119. The horizontal control circuit 116 and circuit 660 provide the major horizontal deflection voltage for positioning a character in its desired location in a line of composition, while further circuits 459, 452 provide the minor horizontal and vertical deflection voltages for illuminating the face of tube 115 in a raster pattern while output 486 from character generator 114 controls the intensity of the beam to form each character. Interpolation circuit 660 is supplied with a reference signal from the selected circuit 600 providing the major horizontal deflection signal; circuit 660 supplies a voltage to circuit 459 to compensate for non-linearities in the cathode-ray tube allowing each of the characters to be displayed with consistent size and intensity across the face of the tube. Point size information is fed from memory 523 in circuit 116 to a relay reed circuit 641 which modifies the minor deflection voltages from circuits 452, 459 to provide the required size of character. A further digital-to-analogue circuit 502 provides for the production of oblique or italic type by modifying the minor horizontal deflection as a function of the minor vertical deflection. The leading control circuit 117 operates a stepping motor 118 to advance photosensitive material 119 in one point increments, but fine adjustment can also be achieved through circuit 780. Indent and spacing instructions are stored in circuits 520, 521 from decoder outputs and function through circuits 116 and 600 to supply the correct major horizontal deflection. Backspacing for operations such as kerning, underlining and providing accent marks is also possible in response to reversing circuit 556. Character - veneration.-Disc 41, Fig. 14, is illuminated by lights 416 and on a command from decoder 113, a shutter (not shown) is opened and allows light from one band to fall on fibre optic transmitters 420. Each track of each band is operatively connected with photomultipliers 417 which are connected in turn to pulse-forming circuits, some bearing- reference signals and others control information, which form the inputs of the character generator raster and z-axis control 423, parts of which are shown also in Fig. 10.