Patent GB-638495-A (GB)
Title: Improvements in methods and apparatus for photographically composing text matter
IPC: B41B23/00
Filed: 1946-08-08
Abstract: 638,495. Photographic type - composing. WESTOVER, G. Aug. 8, 1946, No. 23601. [Class 98 (i)] A method of photographically composing on a single photo-sensitive image-carrier a form consisting of or including a column of justified lines of corrected text matter includes the steps of assembling in an optical projection system a main strip of uncorrected justified lines of text matter and a second strip of justified correcting lines of text matter to be substituted for lines on the main strip, and then optically projecting on to the image-carrier those lines of the main strip not requiring correction and correcting lines from the second strip, line by line, and in the order in which they are required in the finished form. Lines comprising additional matter may be set on a subsidiary line strip or strips which is or are also. assembled in the optical projection system, in which case composition is effected by feeding the line strips independently of one another through the projection system, relatively moving the image-carrier and the projection system in a direction perpendicular to the justified lines and so projecting lines on to the image-carrier, one at a time, and in the order in which they appear in the finished column, as to combine into a column lines from the main line strip and from at least two subsidiary strips. The strips may be fed through the projection system between successive projection operations by steps equal to the spacing of the lines, while the spacing of the lines on the image carrier is determined by feeding the image carrier through steps of a magnitude independent of the spacing on the line strips. The strips may be projected from a common projection station, the selection of the strip from which a particular line is to be pro. jected being effected by simultaneously displacing the strips together with their respective feeding means, preferably angularly about a common axis. Apparatus for carrying out the method includes feeding means adapted to feed the several strips independently of one another and line by line, an optical projection system for projecting an image of a single line on any strip to an exposure station, control means for selecting any one strip for projecting lines therefrom, a holder for so holding a photosensitive image-carrier that the required position of a line of type on the image-carrier registers with the exposure station, and holder feeding means adapted to effect between successive exposures relative movement of the holder and exposure station perpendicularly to the justified lines. The line-bearing strips may be produced by the method described in Specification 638,550. There may be a strip bearing uncorrected text, a second strip bearing correcting lines of text to be substituted for incorrect lines on the first strip, and other strips bearing sundries such as chapter headings and page numbers for insertion into the final form, The apparatus has a circular turret 157, Fig. 2A, rotatable on a central hub on a part movable on horizontal rails 161 in the base of the machine. The turret is divided into five compartments, each containing one of the above-mentioned strips fed across a slot in the turret by sprockets 182, 183, and a condenser 179 concentrating light from a source in the hub on to the strip near the slot. The turret may be rotated to bring the strip &c. in any compartment opposite a lens 232 on a mount slidable on rails 233, 234, and may be locked in any of the five corresponding positions, or in any of five intermediate positions, by a plunger 223 urged into recesses 224. The image of the type line opposite slot is formed on a light-sensitive plate 247, Fig. 2B. Various degrees of magnification are obtained by adjusting the turret 157 and lens 232<SP>1</SP> along their respective horizontal rails by means of spacers 287, 288, the light path being enclosed by telescopic tubes. When one strip is at the projection station, another strip is at a viewing station, where a line thereof is projected by a lens 228 and mirror 227 on to a ground glass screen 226. The position of the line thus projected can be adjusted for subsequent projection by lens 232<SP>1</SP>. The strip sprockets have gears 186, 187, Fig. 10, engaging gear wheels 188 fast with clutch members 191. The clutch members associated with the strips at the projection and viewing stations respectively engage clutch members 192, 192A, which may be disengaged therefrom by a handle 214 to allow the turret to rotate. After a line proprojection, a rod 203 rotates, driving through skew gears shafts 199, 193 ; and thence, through the clutch, the shaft 189 and the driving sprockets, moving the strip at the projection station through a distance equal to the line interval on the strip. A hand wheel 206 on a shaft 199A drives through skew gears, a shaft 193A ; which drives, through the clutch, the strip at the viewing station. The dark slide assembly 156, Fig. 2B, has a shutter with sliding plates 250, 251 with slots which register to open the shutter and to allow the image of a line to be projected therethrough and through a slot 249 in a vertical plate 243 on to a photographic film in a holder 247, slidable in vertical guides by a nut 262 moving on a threaded rod 263 on a shaft 265, Fig. 13, driven by rod 203 through gears and a clutch 270. A motor shaft 274 drives, through a belt 275 and worm gear 276, a shaft 277 connected by a clutch 279 to a surrounding sleeve 278 fast with a cam 280 and the driving member of a Geneva mechanism 281, 282, rotating shaft 203 intermittently. The intermittent rotation of shaft 203 drives, through means described above, the holder and the strip at the projection station. In operation, the strips are loaded into the turret and each in turn adjusted at the viewing station by hand wheel 206 to position the first line for projection. A film is placed in the holder 247, which is set by a handle 269, Fig. 13, to its lowest position, clutch 270 being meanwhile disengaged. After preliminary adjustments, the strip bearing, e.g. uncorrected text is brought to the projection station, and the clutches are engaged. Cam 280 rotates to operate the shutter, after which the Geneva mechanism 281, 282 rotates shaft 203 through a quarter turn, moving the film holder and the strip each through a line interval (which may not be the same, in proportion to character height, in each case ; being preferably proportionately greater on the strip). When incorrect lines are reached, the machine is stopped, and the turret rotated to bring the strip bearing corrected text to the projection station and corrected lines printed therefrom. The incorrect lines are byepassed by means of the hand wheel 206 with the main strip at the viewing station, after which printing from that strip proceeds. Other strips are brought to the projection station when it is required to insert matter therefrom. The process is facilitated by producing proofs of all the strips which are cut up and pasted together to provide a key proof. Specification 499,859 is referred to in the Provisional Specification.