Patent GB-638550-A (GB)
Title: Improvements in methods and apparatus for photographically composing text matter
IPC: B41B23/00
Filed: 1946-08-08
Abstract: 638,550. Photographic type - composing. WESTOVER, G. Aug. 8, 1946, No. 19792/49. Divided out of 638,495. [Class 98 (i)] Relates to a method of photographically composing a form consisting at least of justified lines of text matter arranged in a column, which includes the steps of positioning under control of a previously prepared record strip, a master plate bearing characters so as to bring selected characters one at a time into a projection station and optically projecting the characters so selected in succession along a line lying transversely of a photo-sensitive line strip to compose a justified line of text matter, thereafter feeding the line strip longitudinally under control of the record strip and repeating the foregoing steps, the intervals between succeeding lines being uniform, processing the line strip to develop the line images composed thereon, positioning the developed line strip so as to bring lines thereon one at a time in succession into a second projection station and optically projecting complete lines one at a time from the second projection station on to a photo-sensitive image-carrier in an exposure station, and between succeeding line projections displacing' the image-carrier relatively to the exposure station and perpendicularly to the length of the lines thereon. According to the invention the spacing between lines on the one strip is determined by the design and arrangement of the mechanism for feeding the strip through the first projection system and the strip is then fed through the second projection system by mechanism so designed and arranged as to feed the strip between successive projection operations by an amount equal to the spacing so determined, while the imagecarrier is fed between successive projection operations by a uniform amount which is determined independently of the amount of movement of the line strip. The projection of the lines from the developed strip may be carried out by the method described in Specification 638,495. The characters may be reduced in projection on to the intermediate strip and enlarged in projection on to the page carrier, and may be spaced with a greater line interval, in proportion to the character size, on the intermediate strip than on the page carrier. The line strips may be prepared on perforated film with the lines formed at a constant spacing from the perforations. When the master plate bears negative characters, the strip may be developed by a reversal process to provide negative characters also on the strip. The characters are carried by a master plate 40, Fig. 1, illuminated by a lamp 41 and movable to bring any character into position for projection by means controlled by a record strip, as described in Specification 499,859. The character images are projected by a lens 55 on to a strip of photographic film 59, moved laterally between exposures to give justified lines of character images, and longitudinally between lines by means controlled by the record strip. The film strip on which character images are recorded is wound from a spool 57 to a spool 58, Fig. 10, or vice versa, within a camera case 56 fixed to a sliding carriage 82. It is of 35 or 60 mm. width with perforated margins engaging the teeth of sprockets 60, 61, driven by a sprocket 69. Between the sprockets 60, 61 the film passes across a slot 62, having a rotatable shutter 80. The camera carriage slides in guides 289 parallel to the axes of the film spools. A slidable bar 294, Fig. 9, coupled to the character and space feed mechanism, moves through a distance proportional to the width of the character last (or next to be) projected. An electromagnet 296, carried by bar 294, is energized during this movement, and carries with it an armature 297 fixed to a rack 298 meshing with a toothed sector 299. This sector is fast with a toothed sector 302 on a common shaft 300 ; sector 302 meshes with a rack 83 on the camera carriage 82, which is thereby shifted along guides 289. Sectors 299, 302 may be replaced by sectors having a different ratio of radii to vary character spacing, the bearing of shaft 300 being raised or lowered as required. During the return movement of bar 294, electromagnet 296 is de-magnetized, and a stationary electromagnet 291 is energized to hold an armature 293 on the carriage 82, which is thus held stationary. After each feeding movement (except when a space is to be recorded) an exposure is made through a shutter below the master plate 46 consisting of two plates 43, 44 slidable in opposite directions under the action of bellcrank levers 47, 48, rocked by vertical movement of a pin 51 engaging their slotted ends, actuated by the means (not shown) that raise and lower master plate 40. The plates have apertures 45, 46 which are brought into register to open the shutter. A. second similar shutter comprising plates 52, 53 is closed after the line is completed by means described below, or alternatively by a hand control 54, Fig. 1. At the end of each line the film is moved by the interline distance by rotating a shaft 115, Fig. 9, splined in the hub of sprocket 69. A motor 84, Fig. 1, drives camshafts 88A, 88B, with cams effecting various movements under control of the record strip, and a shaft 92, which may also be turned by hand. Shaft 92 is geared to a shaft 95 which is coupled to a sleeve 97 at the end of a line only. The sleeve is geared to a shaft 112, in turn connected by gearing to shaft 115. Part of the gearing can be reversed in sense to reverse the film drive. A cam 113 on shaft 112 operates the shutter plates 52, 53 between lines, and another cam 114 on the same shaft actuates a return tappet 134 which returns the camera carriage to prepare for the next line. The continuouslyrotating shaft 95 and the intermittentlyrotating shaft 112 have couplings 138, 139 respectively which drive cams operating several pairs of electrical contacts (Figs. 3, 31, not shown). Shaft 95 operates contacts which supply magnetizing D.C. pulses followed by de-magnetizing A.C. pulses to electromagnets 291, 296 in proper timed relation for their operation, as described above. Contacts operated by shaft 112 de-magnetize both magnets during the return of the camera carriage. When the complete text has been composed, the strip is processed, and a proof is prepared on photo-sensitive paper. The proof may be corrected, and a second strip prepared, consisting of corrected lines. Chapter headings and other sundries may be prepared on other strips. These strips may be used to prepare the final text by the method described in Specification 638,495. Specifications 8633/99 and 17199/08, [both in Class 100], also are referred to.