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Magnetostrictive Exciter for Magnetic Ink Jet Printer

IP.com Disclosure Number: IPCOM000086418D
Original Publication Date: 1976-Sep-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Eller, CP: AUTHOR [+2]

Abstract

Magnetostrictive exciter 10 comprises a nickel tube 11 or other magnetic material with a high magnetostrictive constant and a magnetizing coil 12 wound on bobbin 12a, connected to an energizing circuit 13. A second coil 14 wound concentrically on coil 12 is energized by a DC current from source 15 to provide a bias magnetic field, which reduces the droplet breakoff distance and improves the droplet stability. (A permanent magnet may also be used to provide bias magnetic field.)

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Magnetostrictive Exciter for Magnetic Ink Jet Printer

Magnetostrictive exciter 10 comprises a nickel tube 11 or other magnetic material with a high magnetostrictive constant and a magnetizing coil 12 wound on bobbin 12a, connected to an energizing circuit 13. A second coil 14 wound concentrically on coil 12 is energized by a DC current from source 15 to provide a bias magnetic field, which reduces the droplet breakoff distance and improves the droplet stability. (A permanent magnet may also be used to provide bias magnetic field.)

When current, either polarity, is applied to the drive coil 12, the magnetic material will either expand or contract depending on whether the magnetic material has a + or - coefficient. Magnetic ink is supplied under pressure through tube 11 to nozzle 16 to form a constant stream, which is broken up into ink drops 17 at a desired frequency determined by the frequency of vibration of exciter 10.

The wavelength or droplet separation (Lambda) is determined by the frequency of vibration and the velocity of the ink stream (Lambda = velocity/ frequency). The wavelength to diameter ratio (Lambda/d) is in excess of 3.14. The droplets are then deposited on a record medium by selector, deflector control, not shown, to record printed data.

The energizing circuit 13 is able to be operated at frequencies other than resonant frequency of the magnetostrictive exciter. Good drop formation is possible over a broad band of frequencies on either side of t...