Patent GB-1427544-A (GB)
Title: Electroforming a flexible electrically conductive endless metal belt
IPC: C25D1/04
Filed: 1973-05-04
Abstract: 1427544 Electro-forming an endless metal belt XEROX CORP 4 May 1973 [8 May 1972 (2)] 21264/73 Heading C7B A flexible metallic endless belt (e.g. of Ni for subsequent coating with photo-conductor material and use in electrostatographic reproduction apparatus) is electro-formed on a cylindrical mandrel 240 which is supported, rotated and electrically connected by means of a vertical shaft 209 and a hanger 238. The anode is of metal chips 251 contained in an annular basket 276, 278. In making the belt, the mandrel is pre-heated in a tank (75), Fig. 6 (not shown), to the temperature of the electro-forming solution, transported to the solution, rotated and metal coated therein, transported to a cooling tank (79) and cooled therein to facilitate removal of the formed belt, the mandrel and belt having different coefficients of expansion. The belt is removed at a parting station (73) and sprayed with water. The electro-forming solution is circulated through an electrolytic parification tank (336) where metallic impurities are removed, filtered (at 364) and returned through heat exchangers (369, 371) to the electro-forming tank. The mandrel with the formed belt thereon is washed in a recovery tank (77) and the used wash water is later used in the make-up of the electroforming solution. Used cooling water makes up the wash water. A conveyer moves mandrels from one work station to another, the conveyer comprising tracks (76, 78), Figs. 1 and 3 (not shown), hoist cables (80, 82), a load bar 84, collars 86, (88) and mandrel hangers 238 (or 90, 92 in Fig. 3). A programmed control, Fig. 4 (not shown), controls operation of transfer and hoist mechanism, rotation of the spindle and switching on and off of the electro-forming power. Electro-plating solution is supplied at 300 through parts 304, 306, 318 and upwardly through apertured riser tubes 326. The solution flows under a baffle 340 through gaps (not shown) and up over a wall 330 into a trough 332 for circulation. The shaft 209 has a mandrel-supporting drive-hub (206), Fig. 10 (not shown), secured at its top end. The load bar 84 of the conveyer lowers a hanger 238 and mandrel 240 on to the hub which make frictional and electrical contact with each other. The bar is lowered so that, as shown, the collar 86 leaves the hanger and mandrel free to rotate. Electrical contact to the shaft is by a slip ring assembly 242. Anodic contact to the basket is through a bus-bar and terminal (283, 281), Fig. 11 (not shown). Sludge produced during the electro-forming is prevented from reaching the mandrel by a fabric sheet filter (286), Fig. 11, positioned along the inner wall 278 of the basket. The fabric sheet is held in place by a metal perforated sheet 294. Specified electro-forming conditions are:- an anode of depolarized Ni chips; a solution of nickel sulphamate, nickel chloride, H 3 BO 3 , sodium lauryl sulphate and the sodium salt of saccharin; and a mandrel comprising a Cr layer on a core of Al, Al alloy, Cu or stainless steel. The electrolytic purification tank (336), Fig. 2 (not shown), has a pair of corrugated stainless steel cathodes (368, 370) and tubular Ti anode baskets (372) each having a fabric filter anode bag (not shown). Specifications 1288717 and Specification 1365132 are referred to.