Patent GB-956968-A (GB)
Abstract: 956,968. Photographic type composing. INTERNATIONAL PHOTON CORPORATION. July 1, 1960 [July 2,1959], No. 23143/60. Heading B6W. A method of photographically composing a line of text by projecting images of selected master characters arranged on a matrix to appropriate character image positions on a lightsensitive sheet, the master characters of a given kind being arranged in a single line or rank and having an associated " rank value," i.e. a quantity which is a measure of the distance of the character from a pro-determined point on the matrix rank, comprises sweeping the potential images of all the master characters simultaneously lengthwise of the line to be composed so that a potential image of each of the master characters is superimposed in turn on each of the character image positions in the' line; computing from the rank values of the master characters and the widths of the characters including interword spaces preceding each selected character the " displacement value " of each such character, i.e. a measure of the distance between the position in the line of the character and the position of the character at the start of each sweep; operating a timing device in synchronism with the sweep so that its output is instantaneously significant of the positions of the potential images of the master characters during the sweep; and projecting images of selected master characters to corresponding character-image positions on the sheet at instants determined by a predetermined relationship between the displacement values and the instantaneous output of the timing device. As described, the master characters on the plate 10 have widths based on units of 1/18 th of an em and are arranged alphabetically in the rank with a file interval of 20 units. Fig. 2 shows the sequence in which the characters are recorded; while Fig. 5 indicates how the displacement value is computed for each of the characters in the column 9, this value being the total in the column 11 of the rank value adjacent the column 9 and the width of the accumulated length of the preceding part of the line including interword spaces, column 13 the order of the displacement values and hence the sequence of recording. Fig. 1 shows the general mode of operation, the images of the master characters on the plate 10 being swept from position 1 to position 2 across the light-sensitive sheet 8 by displacement of the lens 44 to position 46 and recording being effected by appropriately timed energization of the related flash lamp 21. By altering the size of the interword space in accordance with calculating arrangements described in Specifications 691,738 and 857,791 justified lines may be produced. Apparatus for carrying out the method comprises essentially a keyboard unit and a projection or printer unit, the keyboard feeding a storage device which is read out to operate the printing unit. Since the speed of the printer is greater than that of keyboard operation several keyboard units each punching a paper tape may be used to feed one printer which may be separate from all of them, and justification may be effected in either the keyboard or printer units. Non-justified lines or short lines at the ends of paragraphs should be accompanied on the tape by a suitable non-justifying space code. First embodiment.-In the schematic of Fig. 6, keyboard 23 operates character width coder 25, interword counter (not shown) and character and space identity recorder 29 which also records the character widths. Width codes for successive characters are fed to the character width accumulator 27 which together with the chosen justified line length value and number of interwords operates a justification computor 37 to set up on the justification space storage 39 the required interword space information as in the above-mentioned Specifications but employing electronic instead of electromechanical switch mechanisms. Character and interword identifying signals are fed by a decoder 31 via line 51 to the line code storage 35, which may be a tape, while the decoder also causes the justification information on storage 39 and the " rank value " code for the character, which may be the same as the character identification code, and the character widths from storage 29 to be fed to an adder 33 to provide the " displacement values " which are also recorded in the storage 35. Information in the storage is then used to operate the register 65 of the printer unit, Fig. 7. As the optical system, e.g. lens 44, sweeps the matrix image across the stationary recording sheet 8, which may be a film in a magazine 55 as in Specification 846,268, the sweeping mechanism operates a generator 69 providing timing pulses which are counted by unit 67 which operates a comparison circuit to compare its own count successively with the displacement values stored in independent memories in register 65. For each coincidence an output is fed to operate an illuminoting device 61 for projecting the appropriate master character on to the film in the magazine 55. At the end of a line the register 65 emits a pulse which operates the leading mechanism of the magazine 55 to advance the film upwardly, one line. Second embodiment.-Instead of the Fig. 6 keyboard unit, a simpler one (Fig. 8, not shown), may be employed which merely records on perforated tape character and interword identity, style (e.g. roman, italic, bold and small capitals) and discretionary hyphen codes in accordance with Specification 910,783. Such a tape 73 is fed through a reader 75 (Fig. 9), and the resulting character identity and style signal is fed (a) over line 103 through a distributer 115 to a multiple level magnetic core storage 101 which also stores interword space signals and (b) to a decoder 77 which sends style information to a " style cards " unit 81 as in Specification 807,752 to select the appropriate card and combine this with character identity information to obtain the appropriate character width which is then also fed over line 105 to the same level but a different part of the storage 101 and also to a line length accumulator and justifier 85 preset to a chosen justification length by a selector 107. The decoder also sends interword signals to a counter CI. When the line deficit falls below a chosen maximum value, the accumulator and justifier 85 emits a prepare-tostop signal which is applied over line 87 to the gate 74 so that when the next interword space or discretionary hyphen signal appears on lines 76 or 78 respectively the tape feed is temporarily arrested. The pulse generator 89 then sends pulses through a gate 91 opened by a signal from gate 74 to add repeatedly via line 97 the number stored on the counter CI to the accumulator-justifier 85 until an overflow pulse over line 99 closes the gate 91. By this means the justification computation is effected as in Specifications 691,738 and 857,791, with the difference that the results-interword space value and number of such spaces to be further increased one unit-are stored on electronic rather than electromechanical switches SZ, PR. All the information for the line is now stored on these switches and the core storage 101, typically during the return movement of the sweeping mechanism, but computation of the displacement values for the characters has still to be effected. For this purpose character information is recorded on a continuously rotating magnetic drum 104 about which are disposed writing and reading heads 133, 135 for each of the characters A to Z, the heads for each character having a separate track area and being circumferentially separated by a distance proportional to the rank value plus the mechanical clearance necessary between the heads A, A<SP>1</SP> for the character A of zero rank value. The accumulated line length value is represented by the distance through which the drum rotates after a line start pulse derived from the sweeping mechanism until the writing head for the character is operated, the rotation of the drum from the line start pulse until reading of the magnetized dot record being representative of the displacement value. The sweeping mechanism 143 comprises a carriage 22 (Fig. 10), supporting a lens 20 and a timing grid 24 reciprocated at a steady rate by a double helix endless groove drum cam 50 on a shaft 43 clutched to the shaft 42 driving the magnetic drum 104. The drum carries a magnetic timing track 200 (Fig. 9), read by a head 300 acting as a clock control for a pulse generator 129, while the grid 24 passes between a collimated light source and a photo-cell to produce sweeping clock pulses. The pulses from generator 129 are used to control the instant at which magnetic recording on the drum 104 is effected and hence to determine the displacement value recorded for the character, while the photo-cell pulses are applied to " and " gates in all the circuits of the flash tubes for illuminating the master characters, thereby achieving a fine positioning of the character image. Transcription is initiated by a pulse from the sweeping mechanism 143 as the left-hand margin of the first matrix character image crosses the left-hand margin of the characterrecording area of the film 8, this pulse opening the gate 153 for pulses from the generator 129. The first pulse operates the reader 131 of the core matrix storage 101 which produces outputs of width code 127 and identity code 117. Identity code is translated by the decoder 119 to open a gate to the appropriate writing head 133 for a recording pulse along line 121, while the width code sets up in a flip-flop counter 123 of capacity 31 a count of (32-width value). Pulses are then fed by generator 129 into the counter until this overflows and emits a pulse to step the reader 131 to the next character storage level. Consequently the next and each succeeding character identity code causes the corresponding writing head 133 to make a dot record at