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Coating System for Magnetic Disks

IP.com Disclosure Number: IPCOM000060033D
Original Publication Date: 1986-Feb-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Hinkel, H: AUTHOR [+3]

Abstract

A coating system for particulate magnetic disks is proposed, wherein the dispersion magnets in the spin-off phase rotate in the same sense but not synchronously with the magnetic disk at a slightly lower speed than the latter, leading to a number of advantages. There is no introduction of He gas causing layer thickness distribution problems. The amount of eddy current heat, which hitherto impaired the coating of the second disk side, is noticeably reduced. There is no contamination of magnet edges by spun off ink. The known "window" effect is reduced, as the vertical alignment of the particles in the field of the dispersion magnets is improved. The dispersion magnets rotate in the same sense as the magnetic disk but at a slightly lower speed than the latter.

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Coating System for Magnetic Disks

A coating system for particulate magnetic disks is proposed, wherein the dispersion magnets in the spin-off phase rotate in the same sense but not synchronously with the magnetic disk at a slightly lower speed than the latter, leading to a number of advantages. There is no introduction of He gas causing layer thickness distribution problems. The amount of eddy current heat, which hitherto impaired the coating of the second disk side, is noticeably reduced. There is no contamination of magnet edges by spun off ink. The known "window" effect is reduced, as the vertical alignment of the particles in the field of the dispersion magnets is improved. The dispersion magnets rotate in the same sense as the magnetic disk but at a slightly lower speed than the latter. The relative speed between disk and magnets must be so high that the dispersion magnets are capable of acting on the entire disk and be so low that the use of air does not lead to spoking and eddy currents are reduced to a minimum. If the disk rotates, for example, at 4800 rpm, a magnet speed of about 4200 rpm will suffice, for in that case the Reynold value, the criterion of laminar flow, will be < 105 . The proposed system may be realized in three ways. 1. Conventional orientation magnets are used which, rigidly coupled to each other, rotate at about 4200 rpm during the dispersion/spin-off phase. The orientation phase is as usual,
i.e., while the disk rotates at about 6 to...