Browse Prior Art Database

Air Gap and Torroid Coil Core for Ferromagnetic Fluid Ink Jet Drop Deflection

IP.com Disclosure Number: IPCOM000080997D
Original Publication Date: 1974-Mar-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Risedorf, WF: AUTHOR

Abstract

This structure reduces the amount of time that the magnetic field in the air gap takes to return to a zero value, after the signal to the coil has returned to a zero potential. For drop deflection with ferro-fluids, the amount of time the magnetic field in the air gap is present can influence the rate of drop deflection.

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Air Gap and Torroid Coil Core for Ferromagnetic Fluid Ink Jet Drop Deflection

This structure reduces the amount of time that the magnetic field in the air gap takes to return to a zero value, after the signal to the coil has returned to a zero potential. For drop deflection with ferro-fluids, the amount of time the magnetic field in the air gap is present can influence the rate of drop deflection.

When an air gap deflection coil core is used in a magnetic ink jet printer too much time is required for the magnetic field in the gap to collapse to a level not high enough to influence the drop to be deflected, trailing the just deflected drop. Because of varying hysteresis in core materials used, the rate at which the field collapses varies for each core sample. As examples, for a square-wave signal of seven microseconds pulse time, a silicone iron core (air gap) had a magnetic field present for 30 microseconds. With a core made of Hy Mu 80* metal and the same applied signal, the magnetic field was present for 45 microseconds.

Fig. 1a illustrates an air gap core 1, the gap being designated 1a, while Fig. 1b illustrates the combination air gap-torroid core 2, developed to reduce the time the magnetic field is present in the air gap without additional circuits.

The operation of the air gap-torroid coil core 2 of Fig. 1b is as follows: As the magnetic field is increasing due to a signal to coil 3, the magnetic field will be felt through the torroid section 2b until that...