Browse Prior Art Database

Synchronization of Magnetic Ink Jet Printer

IP.com Disclosure Number: IPCOM000079712D
Original Publication Date: 1973-Aug-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 3 page(s) / 25K

Publishing Venue

IBM

Related People

Pimbley, WT: AUTHOR

Abstract

A magnetic ink jet printer consists of a nozzle 10, through which a stream of ferromagnetic ink 12 is ejected under pressure for printing on a document 13. A gutter 15 catches drops not used for printing.

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Synchronization of Magnetic Ink Jet Printer

A magnetic ink jet printer consists of a nozzle 10, through which a stream of ferromagnetic ink 12 is ejected under pressure for printing on a document 13. A gutter 15 catches drops not used for printing.

A magnetic modulator 14 which imposes a perturbation on the ink stream close to the nozzle, uses a magnetic field gradient directed along the stream by a pulse of current through a winding 16 on a magnetic core 18.

A deflector 20 comprises a magnetic circuit having a winding 22 and a shaped gap that produces a gradient field. The action of this gradient field on the induced magnetization of each drop produces a deflecting force.

The magnetic deflector 20 must be pulsed at the time when the drop is in the gap of the deflector, so that there must be synchronization between the deflector pulses and the drop stream.

The pulses to the modulator 14 tell when a drop is started.

The point in the ink stream that is in the modulator gap at the time of a pulse, eventually becomes the center of a drop. Therefore, the time between a modulator pulse and a deflector pulse to deflect that drop must be L = s/v (1), where s is the distance between the modulator and the deflector, and v is the velocity of the ink stream.

Since the two units are separated by many wavelengths (Lambda=v/f), the proper phase difference between the two signals would be given by this time minus an integral number of periods (T=l/f). Thus the time or place of drop formation are of no critical importance.

The separation of the deflector 20 and modulator 14 is, of course, constant. If the stream velocity were also constant, there would be no serious synchronization problem. Since the velocity is bound to vary with temperature and ot...