GB963077A - Apparatus having a feeding device for feeding processing fluid between superposed sheets - Google Patents

Abstract

963,077. Processing photographic sheets. INTERNATIONAL POLAROID CORPORATION. April 26, 1962 [April 26, 1961], No. 16008/62. Heading G2A. [Also in Division D1] Superposed sheets, e.g. photographic papers, are treated with processing fluid by guiding the sheets through an apparatus which separates them along one edge, and pressure-feeds the fluid between them at said edge. Fig. 1 shows the arrangement incorporated in a self-developing camera, in which the photographic image is made on the positive sheet 18 by diffusion-transfer from the exposed negative sheet 17. The sheets are pressed together, prior to extraction from the camera, between pairs of rollers 21, 22 and 23, 24. As the sheets pass from the upper to the lower rollers, the processing liquid is introduced between them. In order to prevent escape of fluid between the edges of the sheets, these are clamped together as shown in Fig. 10. The clamps comprise an inner U-shaped member 38 fixed to and sliding in another U-shaped member 37. The lower flanges of the two members grip and squeeze together the edges of the two sheets as these move along longitudinally. The central parts of these flanges are curved away from each other, as at 42, 43, to allow entry of a short tube 44 through which the fluid is introduced. The two sheets pass one above, and one below, this tube, so that the fluid enters between them. This tends to cause the sheets to bulge apart, forming in effect an elongated fluid container, bounded along one edge by the clamps 37, 38, and along the other edge by a similar clamp which grips the sheets without having any curved parts such as 42, 43. This fluid-containing part is bounded transversely, across the sheets, by pressureapplying surfaces, such as the rollers 21, 22 and 23, 24, between which the sheets pass, and which spread the fluid over the surfaces to be treated as the sheets pass between them. The fluid is inserted through the tube 44 by means of a needle similar to a hypodermic needle, from a supply in a pressurized container, which may have a control valve to allow a predetermined quantity of fluid to pass. Fig. 9 shows the processing method applied to a photocopying machine. Photosensitive paper from a roll 79 is passed, together with an original sheet 81 inserted through an opening 91, round a transparent drum 85 containing a light source 82. Within the drum is fixed opaque sleeve 83 having a slot 84, the exposure being made as the papers pass across this slot. The original then passes out of the machine again through slot 93, while the exposed sheet passes on towards the development section. This is provided by upper and lower trough-like members 80, 90, within which is a nozzle 100 through which processing fluid is introduced in the manner already described. To assist in confining the fluid to the sheet 79, a second sheet 101 in the form of an endless belt is provided, whose purpose is only to spread and confine the fluid. The abutting edges 95, 96 and 97, 98 of the troughlike members act as the pressure-applying surfaces of the previously described embodiment. The processing fluid may be introduced simultaneously from both edges, instead of from one edge only. Specifications 684,591, 684,592, 684,595, 684,596, 685,685, 714,412, 825,146 and U.S.A. Specifications 2,435,720, 2,579,587, 2,612,452, 2,630,385 and 2,647,056 are referred to.