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Browse Prior Art Database

Particulate Magnetic Disks With Concentric Particle Strands

IP.com Disclosure Number: IPCOM000061214D
Original Publication Date: 1986-Jul-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Brunsch, A: AUTHOR [+3]

Abstract

For a servo system, as described in principle in the IBM Technical Disclosure Bulletin 22, 8A, 3268 (January 1980), the magnetizable particles are compressed by a high magnetic field, changing periodically in a radial direction, to form circular strands of a particular width in the coating. Particulate magnetic disks are spin-coated with magnetic ink. The magnetic particles are subsequently aligned in parallel in the field of an orientation magnet while the coating is still moist. The known window effect is utilized to structure the particulate magnetic disk for servo applications. For that purpose, each particle strand constitutes a track. The particle strands are formed as follows.

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Particulate Magnetic Disks With Concentric Particle Strands

For a servo system, as described in principle in the IBM Technical Disclosure Bulletin 22, 8A, 3268 (January 1980), the magnetizable particles are compressed by a high magnetic field, changing periodically in a radial direction, to form circular strands of a particular width in the coating. Particulate magnetic disks are spin-coated with magnetic ink. The magnetic particles are subsequently aligned in parallel in the field of an orientation magnet while the coating is still moist. The known window effect is utilized to structure the particulate magnetic disk for servo applications. For that purpose, each particle strand constitutes a track. The particle strands are formed as follows. The magnetic particles are oriented in a high, substantially horizontal, magnetic field that changes periodically in a radial direction and whose periodicity corresponds to the desired track density. As the magnetic particles preferably migrate in the direction of the highest magnetic field, windows (or regions with few magnetic particles) occur at the location of the lowest magnetic field, i.e., between the tracks, thus structuring the previously continuously applied magnetic coating. The servo signal for track following is deduced from the read signal which decreases in response to deviations of the read element from the tracks. The periodically changing magnetic field for structuring and simultaneously orienting the magne...