Patent GB-1009709-A (GB)
Title: Photocopy apparatus
IPC: G03B21/11
Filed: 1962-10-23
Abstract: 1, 009, 709. Projection printing apparatus; projectors. H. ADLER. Oct. 23,1962, No. 40008/62. Headings G2A and G2J. [Also in Division B4] Apparatus for viewing and projection printing microfilms comprises a film projection head 12, rotatable about the axis of projection lens 30, which is mounted on an angled top 11 of housing 10 and projects an image of film strip 26 on to viewing screen 38 after reflection at mirror 34. For printing of selected frames, a mirror 46 pivoted at 48 is movable to intercept the projection beam and reflect the image downwardly on a sheet 44 of photo-sensitive paper carried on easel 42 and stored in the machine on supply roll 52. After exposure in this manner, mirror 46 is lowered again and the sheet is carried through developing section 50 and leaves the machine. A motor-driven programming mechanism 60 automatically feeds paper on to easel 42, but first turns off the projection lamp and raises mirror 46 before energizing the lamp again for a pre-determined period to expose the paper. While the print is being developed, the mechanism 60 advances and cuts off a further length of paper from roll 52 and centres it on the easel for a subsequent printing operation. The film strip is advanced by hard-cranks 22, 24. The intensity of the lamp may be varied. Programming and paper drive mechanism. Fan-cooled motor 64 drives the mechanism 60 through drive gear 66 and pinion 68 on countershaft 70 whose spline 72 meshes with an idler 74 which in turn meshes with main gear 67 on the shaft 62, thus shaft carrying an assembly of gears and cams and rotating one fall revolution for each cycle of the apparatus, this assembly comprising timing cam C4, an intermittent drive gear 78, a locking cam 80, a motor control cam C5, a shear cam C6, a spacer 82, and a mirror cam C3. The gear 78 drives a paper dispensing roller 94 mounted below plate 55 and extending upwardly through an opening. The intermittent drive of constantly rotating gear 78 is imported by the absence of teeth on sections 151, 152 so that gear 84 is only driven when engaged by toothed sectors 146, 148, and is braked during the rest periods by the engagement of scalloped edges 154, 155 of cam 81 with sectors 151, 152 of cam 80. A tooth is removed from gear 84 where the gear teeth first meet. The cut and exposed paper is advanced by roller 100 connected by chain and sprocket to roller 94, while squeeze rollers 124, 126 are continuously driven by chain and sprocket form countershaft 70 and remove excess developing fluid from the print which is then passed to the operator. Shearing mechanism. A movable blade 164 spring-urged upwardly by spring 180 has a diagonal cutting edge 170 and a pair of rearwardly extruding arms 172, 174 pivotally engage a rockshaft 176 passing through shear frame 186. The movement extended by spring 180 also biases blade 164 into contact with fixed blade 166. Frame 186 pivots counter clockwise about axle 188 when its follower 190 engages the lake of cam C6, and blade 164 is driven downwardly for the cutting stroke. Blade 164 is inclined at a horizontal angle to blade 166 to give a clean cut. Frame 194 slightly above easel 42 has an upwardly turned lip 196 to guide paper 44. The paper is locked during cutting by the stop button 206 on an end plate 200 pivoted at 188 and having a nose 202 which bears against shaft 176 when the blade is raised. As blade 164 moves downwards, plate 200 is rotated counterclockwise by spring 204 and button 206 engages the paper through aperture 208. Mirror lift mechanism. The position of mirror 46 as determined by cam C3 through cam follower 216 and a linkage 214 to mirror lift arm 210 pivoted at 212. The lowering of the mirror is timed so that the mirror edge adjacent pivot 48 meats the leading edge of the following sheet of unexposed paper and tucks it under the lip at the easel frame 194, so flattening the sheet. Paper threader. A spring paper stop beneath easel 42 has a finger which projects upwardly through openings in the easel and thereby engages the leading edge of paper fed through passage 58, and positions it. When the machine is started the finger is lowered by means of cam C5 and lever 240 and is held down by the paper until the entire roll is finished.