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Ultrasonically Assisted Filtration of Magnetic Media Inks

IP.com Disclosure Number: IPCOM000045692D
Original Publication Date: 1983-Apr-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Bradshaw, RL: AUTHOR [+5]

Abstract

Filter efficiency and life may be greatly increased by providing a low energy, ultrasonic vibration at or near the filter surface, preventing rapid agglomeration of the primary particles near the filter.

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Ultrasonically Assisted Filtration of Magnetic Media Inks

Filter efficiency and life may be greatly increased by providing a low energy, ultrasonic vibration at or near the filter surface, preventing rapid agglomeration of the primary particles near the filter.

Magnetic attractions between magnetic particles as used in coatings for magnetic recordings produce flocs of the primary particles. These flocculated particles are undesirable in the finished coating since they hinder the orientation of the particles in the finished coating. The formation of the flocs depends on (1) the viscosity of the ink, (2) the density of the particles in the medium, and (3) the stability of the dispersion. Filtration is greatly impaired. Further, filtration can be rendered useless if not carried out immediately prior to the application of the ink to the substrate.

Low energy, ultrasonic vibration is capable of reproducibly and reversibly breaking the flocs back down to the primary particle size.

Ultrasonic dispersion at or near the filter surface prevents. the rapid flocculation of the primary particles near the filter interface. The ultrasonic vibration also maintains the quality of the dispersion through the transport process to the coating head. Primary flocculation is reproducibly dispersed by the ultrasonic vibration placed in the flowing system. The placement of the ultrasonic vibration device is critical since reflocculation can occur as soon as the ultrasonic shear is removed...