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Application of Ultrasound And Electron Beam Techniques to Magnetic Recording Media Production And Process Control Therefor

IP.com Disclosure Number: IPCOM000120784D
Original Publication Date: 1991-Jun-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 2 page(s) / 102K

Publishing Venue

IBM

Related People

Roylance, D: AUTHOR [+5]

Abstract

The production of magnetic recording media typically includes milling of the magnetic ink to disperse the particles therein, filtration of the ink, coating a substrate with the ink, and drying the media. One problem associated with such production is the agglomeration of magnetic particles in the ink upon completion of milling. The particle aggregates (1) clog the ink filters, (2) reduce recording media performance, and (3) reduce coating uniformity. The problems thus presented are how to improve particle dispersion or the associated detrimental effects caused thereby and how to implement those improvements in a manufacturing environment.

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Application of Ultrasound And Electron Beam Techniques to Magnetic
Recording Media Production And Process Control Therefor

      The production of magnetic recording media typically
includes milling of the magnetic ink to disperse the particles
therein, filtration of the ink, coating a substrate with the ink, and
drying the media.  One problem associated with such production is the
agglomeration of magnetic particles in the ink upon completion of
milling. The particle aggregates (1) clog the ink filters, (2) reduce
recording media performance, and (3) reduce coating uniformity.  The
problems thus presented are how to improve particle dispersion or the
associated detrimental effects caused thereby and how to implement
those improvements in a manufacturing environment.

      The aforementioned problems are solved by applying ultrasonic
and/or electron beam energies to the ink or coated media at various
points in the production process. By sonicating the ink prior to
filtration, bubbles are created in the ink solvent solution which,
upon implosion, disperse the particle aggregates.  By sonicating the
filtered ink again before coating, the binder and particles are
provided with enough energy and placed in such proximity as to
improve coating strength which is related to media durability.  Also,
the drying process can be supplemented by electron beam irradiation
to create crosslinking sites within the coating to improve its
strength.  These enhancements, each at a different point in the media
production process and at a specific optimized input energy, can be
used singly or together.

      The application of ultrasound and electron beam irradiation to
magnetic recording media production does more than just extend filter
life and improve media coating durability.  The improved coating
uniformity and particle dispersion also results in higher
performance, such as but not limited to improved signal-to-noise
ratios and higher signal amplitudes.  Ink shelf life is improved
because an ink which has been held so long that the particles have
agglomerated to a morally unrecoverable point can undergo successful
particle redispersion by sonication.  The net of the process
enhancements is thus an improvement in performance, coating
durability, and production yields.

      Implementation of t...