Improvements in or relating to web coating apparatus

摘要

834,526. Coating webs. KODAK Ltd. Feb. 23, 1956 [Feb. 23, 1955], No. 26304/59. Divided out of 834,525. Class 140. Apparatus for applying two or more superposed coatings of layer-forming solutions, e.g. of light-sensitive material, to a film, paper, or other web comprises two or more chambers each having an extrusion passage communicating with a common discharge passage, and means for feeding the solutions to the chambers at controlled rates determined by the desired thickness of the individual layers. In Fig. 2 a hopper 10 is internally divided by an adjustable partition 16 into two chambers 24, 25 to which solutions S, S1 are supplied by metering pumps P, P1. The chambers communicate with a discharge slot 11 through which superposed layers of solution L, L1 are delivered to a bead 17 in contact with a moving web W, the layers being deposited on the web without intermixing. The hopper 10 is mounted on a frame which is pivoted about the web-carrying roller 13 and is adjustably securable by a screw engaging an arcuate slot. Screw means are also provided to adjust the hopper 10 angularly, and towards and away from the web. In a modification the hopper 10 contains two wedge-shaped blocks forming partitions providing a single lower chamber and two upper chambers all of which communicate through separate slot-shaped channels with the discharge slot 11. In Fig. 8 the hopper comprises a pair of blocks 40, 41 clamped between end plates, the block 41 having a chamber 46 the forward end of which forms a delivery slot 45 and a convex inner wall 47. The chamber 46 is divided by three partitions 48, 49, 50 into four sub-chambers each of which is supplied with solution through channels 64 and flexible tubes 65-68. The partitions 48-50 are vertically adjustable as by screws 62, and their upper ends are curved forwardly to form regularly curved channels leading to aligned slots 59-61 through which the solutions are directed in superposed layers to the delivery slot 45. The coated web is passed through a drying chamber, preceded if necessary by a chilling chamber.