Patent GB-710274-A (GB)
Title: Improvements in or relating to photographic contact printing apparatus
Inventor: SMITH VICTOR JAMES
IPC: G03B27/02
Filed: 1951-06-05
Abstract: 710,274. Photographic contact printing apparatus. KODAK, Ltd. June 5, 1952 [June 5, 1951]. No. 13299/51. Class 98(2) Photographic contact printing apparatus comprises a negative clamp, a paper clamp, a platen for pressing a sheet of light-sensitive paper into contact with a negative positioned over an exposure aperture, and a single operating member which is coupled to the two clamps and platen by means of a lost-motion connection and is movable to a position in which the negative clamp is closed and the paper clamp and platen are open, to a position in which the negative clamp is also open, or to a position in which the two clamps and the platen are closed. As shown in Fig. 2, an apertured base plate 4 on a lamp-house 2 mounted on a table 1 receives a translucent or transparent sheet and may carry adjustable masking plates. The negative and light-sensitive material may be held against the exposure aperature by means of a pad 9 on a platen 8 pivoted in lugs 11. A rod 24 passes through a bore in an arm 15 extending from the platen 8, and a spring 26 bearing on a collar 27 on the rod pushes arm 15 against a second collar 29 on rod 24. Rod 24 is linked by a bell-crank lever 22 and a rod 21 to a treadle 16 pivoted at 17 to the framework of the table. The treadle may be spring-biased to the position shown. A negative clamp comprising a thin metal plate 31, Fig. 4, is screwed to a member 33 pivoted on a shaft 34 fixed under the baseplate 4. A torsion spring on shaft 34 urged the free edge of plate 31 towards the translucent sheet 6. When treadle 16 is rocked clockwise in Fig. 2, rod 24 moves down, compressing spring 26, and an extension projecting from collar 29 engages an arm 37 fixed to member 33, which is thereby rocked to raise plate 31. A negative N is then placed on the exposure aperture, and is clamped at its upper edge when the treadle is released. A paper clamping plate 41 is mounted on a member 39, also pivoted on shaft 34, and having a torsion spring urging plate 41 towards the baseboard. A headed pin 46 slides in a collar 47 and bears on a lug 45 on member 39. A pin 48 on arm 15 bears on pin 46 so that, when platen 8 is raised, pin 46 is depressed and holds plate 41 clear of the base-plate. When a photographic paper has been placed over the negative N, the treadle 16 is rocked anti-clockwise in Fig. 2. As the platen begins to move pin 46 is released and plate 41 grips the edge of the paper. The movement of the treadle is continued until the pad 9 presses the paper and negative together against the exposure aperture. The platen movement may switch on the printing lamp. A cover plate 49 is fixed to and spaced from the member 33 overlies the plate 41 and has a flange 54 on each side to assist in holding the negative. Knobs 51 threaded on screws passing through slots in plate 41 clamp the plate adjustably. Bars (not shown) fixed on each side of plate 41, when a strip of film is used, clamp the strip on each side of the exposure aperture. When the platen is raised after exposure, the paper slips down to a retractable stop bar 60, where it is stamped by a numbering device 59 as described in Specification 710,316 and then allowed to drop into a slot 65 in the table top. A tray 64 has one end wedged in slot 65, and is pivoted at its other end to a shoot 61 pivoted at 62 to the lamphouse. In the full-line position. shown, papers falling into slot 65 fall down the shoot into a tank or the like (not shown). If all the prints made from one film strip are to be collected, the shoot and tray are moved to the dotted-line position so that the papers collect in the tray 64. The shoot and tray are then brought into alignment again, and the papers fall down the shoot together.