Patent GB-537685-A (GB)
Title: Improved photographic apparatus for producing line-justified copies of documents
IPC: B41B27/32
Filed: 1939-12-13
Abstract: 537,685. Photo-electric control of photographic type-composing machines. INTERNATIONAL BUSINESS MACHINES CORPORATION. Dec. 13, 1939, No. 32167. Convention date, Feb. 8. [Class 40 (iii)] [Also in Group XX] A photo-line-composing machine comprises an optical system which is reciprocated to scan the lines of the copy and project the images on to light sensitive material, together with automatic means which justifies the lines during the printing. In the apparatus described, the amount of justification requisite for each line is measured by photo-electric means which correspondingly adjust means which move the light sensitive material during the photographing of the line through the requisite distance to justify the line. In the apparatus shown, the document 30 to be copied, which may be in the form of a sheet or of a strip wound between feed and take-up rolls (not shown), is fed by sprocket rollers 50 engaging holes in its edges so as to bring each line successively to the scanning position behind a slot 178 in a presser plate 172, Fig. 4. The sprocket shaft 49 is driven by a pawl and ratchet operated through a link and lever system by a cam 71 on the drive shaft 37. The presser plate 172 is carried by arms 173 depending from a pivoted bar 174 urged by a spring to press the plate against the document. The film 96 passes from a roll 88 in a casing 31, between feed and tension rollers 97, 99, and between a guide plate 108 and cross-bar 109, to a take-up roll 113 in a detachable receiving box 114. It is fed step by step with the document through one line space by a pawl and ratchet operated through link mechanism by a cam on the shaft 37. Each line of the document as it comes into scanning position is projected progressively by a lens 33 on to the film, the lens being mounted on a carriage 32 by which it is traversed along the line. The lens or scanning carriage is mounted by wheels 153, 154 on grooved tracks in the edges of a bar 151, Fig. 13, and is traversed by an arm 158 operated by a cam 156 on the shaft 37. An apertured sliding shutter plate 148 engages at the end of each traverse stops 163, 167, by which it is moved to open the lens aperture during the scanning movement and close it during the return movement. The carriage carries lamps 34 for illuminating the document. In order to justify lines short of the normal length, each line prior to scanning by the lens 33 is sensed for length by means employing a photo-electric cell, which then adjusts mechanism for moving the film in the opposite direction to the movement of the lens during the scanning of the line to expand the line to the required length. For this purpose, the end portion of the line next to be scanned is exposed by a cut-away portion 179 at the end of the slit 178 in the presser plate 172, this cut-away portion coinciding with an aperture in the front of a casing 193 containing a photo-electric cell 192. Light from a lamp 189 passes by way of a condenser 188, prism 180, and slit 210, Fig. 4, in a horizontally slidable plate, through the document to the photoelectric cell. During the scanning of the preceding line, a slide 195, Fig. 4, operated through link mechanism from a rock-shaft 59 moves the slit 210 to the right. When the slit reaches an opaque spot, one of which is placed at the end of each line, the photo-electric cell is de-energized, this causing through a valve amplifier the energization of a solenoid 211, Fig. 8, which effects the requisite setting of the means for traversing the film to justify the line during the next scanning operation. The casing 31 containing the film is carried on a base 89, Figs. 3 and 8, movable on balls running in grooved tracks 93, 94 and is traversed by a link 213 connecting the base 89 to a lever 214 which is rocked by a horizontally movable slide 218 with which it has a pin and slot connection 216,217. The slide 218 is reciprocated by an oscillating arm 216 on the rock shaft 159, a pin 224 on the slide engaging in a groove 225 in the face of the arm. The slide 218 is carried by a block 219 slidable on a vertical bar 220, and during the setting of the justifying means it is raised by being latched to a second block 239 which is reciprocated on a vertical bar 238 by a link 241 connecting it to a lever 242 operated by a cam 245. The latch is formed by a lever 248. Fig. 11, pivoted on the block 219, which engages a shoulder 247 on a bar 246 attached to the block 239, the blocks 219, 239 thus moving upwardly together in synchronism with the movement of the sensing slide 195 and slit 210. When the slit reaches the opaque spot at the end of the line the photo-electric cell causes energization of the solenoid 211, which through a lever 250 and link 249 rocks the lever 248 anti-clockwise, disengaging it from the shoulder 247 and causing a nose 251 on it to engage a rack 253 secured to the bar 220, thus securing the block 219 at the adjusted position. This positions the axis of the stud 224 on the slide 218 at a distance from the axis of oscillation of the arm 226 which is proportional to the amount of justification required, and hence the movement of the slide 218 produced by the next oscillation of the arm 226 during the scanning of the line in question will produce the necessary traverse of the film casing 31 to effect the necessary justification. Fig. 9 shows the stud 224 positioned co-axially with the rock-shaft 159, in which case no movement is given to the film casing, this corresponding'to a line needing no justification. In a modification, the stud 224 is adjustable to either side of the position in which it is coaxial with the rock-shaft 159, so that lines of greater as well as of lesser length than normal may be justified.