GB954480A - Improved recording system - Google Patents

Abstract

954,480. Magnetic recording heads. MINNESOTA MINING & MANUFACTURING CO. April 21,1960, No. 14103/60. Heading G5R. A magnetic tape recording head arranged to produce a uniform intensity of magnetisation throughout the thickness of magnetic layer 13, comprises a conventional head with a gap member between polepieces 16,17 and an associated member, spaced opposite the gap on the other side of the tape and comprising three fine insulated wires 21-23, mounted in a block of magnetic material 19 and so connected to a cooling plate 25 that symmetrical currents of half the intensity of that flowing in the wire 22 flow in the opposite direction down the wires 21, 23. When the heads are simultaneously fed with the same signal current, the component field distributions are as in Figs. 4B, 4C, the resultant field being uniformly along the tape axis over the greater part of the gap, the usual vertical component at the ends of the gap being cancelled out. Typically, the wires 21-23 are 0. 0006 inch dia and 0. 08 inch long, 22 carrying 10 Amps. The arrangement allows recording of high frequencies at low tape speeds without danger of loss of the recording due to tape wear. In another embodiment, (Fig. 5 not shown), the first recording may be made on a double-coated tape, the unwanted recording on the lower coating being erased by a normal erase head whose field does not penetrate in sufficient strength to affect the wanted recording in the upper coating.