Patent GB-886534-A (GB)
Title: Methods of and apparatus for photocomposing text material
IPC: B41B17/06
Filed: 1958-10-17
Abstract: 886,534. Photographic type-composing apparatus. FRIEDMAN, A. Oct. 17, 1958 [Nov. 1, 1957], No. 33186/58. Class 98(1). In a method of photographic type-composing in which a light beam is projected through a selected typographical character and the image thereof is projected on to light-sensitive material, the characters are arranged in vertical and horizontal rows; regarding the vertical rows as being paired off two by two into "double" rows, and the horizontal rows similarly, each intersection of a "double" vertical row with a "double" horizontal row gives an intersection area containing four characters; a limited light beam is projected through a selected one of these four characters to obtain an image of that character; to obtain an image of any of the other three characters in the same intersection area, the whole array of characters is moved so as to bring the other required character into the same light beam. Fig. 1 shows an arrangement in which actuation of the keys on a keyboard 10 provides, besides a typewritten record, a corresponding series of coded signals on a magnetic tape 12, which is fed into the printing control unit 24, where justification is carried out, and the appropriate control signals fed to the main component parts of the printing apparatus, which comprise a series of vertically-disposed lamps 40-44, a type font 37, a series of horizontally-disposed shutters 50-54, a group of small lenses 62, a larger collimating lens 65, and the sheet of light-sensitive material 36 carried on a cylinder 35. The array of typographical characters is set out on the type font 37 as shown in Fig. 4, and is disposed so as to form pairs of vertical rows 101-104 and pairs of horizontal rows 110-114. The disposition is such that the right-hand and left-hand vertical row in each pair of rows (e.g. the pair of rows 102) comprise lower-case and upper-case characters respectively. Also, the upper and lower of each pair of horizontal rows (e.g. the pair of rows 112) comprise "common" and "uncommon" characters respectively. Each of the five flash-lamps shown is in alignment with, and illuminates, a right-hand vertical row in each of the double vertical rows 100-104 (lower-case characters). The horizontally disposed shutters 50-54 are normally closed, but any one of them may be opened by energizing a relay. These shutters are aligned with the upper ("common") row of characters in each of the double horizontal rows 110-114. At the intersection of each vertical double row with each horizontal double row, a square including four characters is defined. The right-hand upper character in each of these squares is both lower-case and "common", and is aligned with one of a series of small lenses 62, the image through any of which is thrown by the large collimating lens on to the sensitive sheet 36, where a mask 125 cuts out unwanted parts of the image. Thus by operating the appropriate flash-lamp and shutter, any character which is both lower-case and "common" may be illuminated and its image thrown on the sheet 36 without any movement at all of the type font 37. The font may be moved to the right a distance equal to the distance between two adjacent rows, or upwards a similar distance. One of these small movements, or both together, make available all the remaining characters on the font, by operating the appropriate lamp and shutter. Thus at no time has the font to be moved either horizontally or vertically more than the distance between two adjacent rows of characters. Fig. 6 shows the mechanism for effecting this movement. By energizing solenoid 60 its armature 145 is drawn upwards, so pushing roller 151 and its mounting lever 152 about pivot 155. The further roller 156 thus pushes the type font to the right, against the spring-loaded roller 157. Similarly, energization of solenoid 61 causes the font to be pushed upwards by rollers 130 against the spring-loaded rollers 127. The light-sensitive material 36 is mounted on a cylinder 35 which is rotated by a motor 72 acting through a clutch 76. When the character has been photographed on sheet 36, the cylinder is rotated the appropriate amount according to the set width of the character. This is controlled by a disc 77 having a series of apertures 80 round its periphery. Light from a source 82 passes through these apertures to fall on a photocell 81, thus generating a series of pulses. When the correct number of pulses for that particular character has been received by the control 67, a brake 71 is energized to arrest the cylinder from further rotation. After a complete line of text has been recorded, the cylinder 35 is moved axially by the rotation of a threaded shaft 92. This rotation is initiated by an appropriate signal on the tape 12, and a multi-lobed cam 96 closes and opens a switch 97 as it rotates, to furnish a series of pulses to the line feed control 87, so that rotation is stopped at the correct moment.