Browse Prior Art Database

Magnetic Ink Jet with Ink on Demand Capability

IP.com Disclosure Number: IPCOM000081053D
Original Publication Date: 1974-Mar-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Pennington, KS: AUTHOR [+2]

Abstract

This nonimpact ink droplet printer uses a ferro-fluid ink as the printing media. It consists of an array of nozzles and an array of magnets, each nozzle 11 being coaxial with one magnet 10. The magnet 10 is a permanent magnet whose field may be enhanced or reduced by a coil or current loop 12 wrapped around it or by other means of perturbing the fixed magnetic field. The figure shows one such nozzle-magnet pair. The nozzle 11 is connected to a ferro-fluid reservoir (not shown) such that it is filled with ferro fluid, but, because of the surface tension (at 13), it does not by itself allow fluid to spill from the nozzle.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 53% of the total text.

Page 1 of 2

Magnetic Ink Jet with Ink on Demand Capability

This nonimpact ink droplet printer uses a ferro-fluid ink as the printing media. It consists of an array of nozzles and an array of magnets, each nozzle 11 being coaxial with one magnet 10. The magnet 10 is a permanent magnet whose field may be enhanced or reduced by a coil or current loop 12 wrapped around it or by other means of perturbing the fixed magnetic field. The figure shows one such nozzle-magnet pair. The nozzle 11 is connected to a ferro-fluid reservoir (not shown) such that it is filled with ferro fluid, but, because of the surface tension (at
13), it does not by itself allow fluid to spill from the nozzle.

On the other hand, introducing a magnetic field at the front of the nozzle will extract ferro fluid from the tip into the gap by creating surface instabilities. The net action of the magnetic force created by the field gradients and the surface tension tears the ferro fluid and forms a droplet 17 which is then attracted to the magnet by a hulk magnetic force. Using a 10 mil capillary tube filled with ferro fluid having M(s) 150 gauss and a permanent magnet with a field on the order of 1000 gauss (the tip being ground to a point), one finds that for distances smaller than some critical value d(c) (approximately 0.5 cm for our example) droplets will be extracted from the tip of the capillary.

In operation, one sets the nozzle-to-magnet distance greater than d(c) (which depends on the strength of the permanent m...