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Process for Monitoring Ink Characteristics

IP.com Disclosure Number: IPCOM000086568D
Original Publication Date: 1976-Sep-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Anschel, M: AUTHOR [+2]

Abstract

Magnetic inks suitable for use with ink jet printing frequently cause clogging of the small diameter orifices through which they flow. Magnetic particles of 150 angstrom size are typically composed of magnetite encapsulated with ammonium oleate used to prevent agglomeration, retard particle growth and oxidation of the magnetite particles. Frequently, the ammonium oleate covers only portions of many of the magnetite particles that can result in agglomeration in a magnetic field. Accordingly, it is desirable to test the inks to determine whether they have satisfactory characteristics. Surfactants tend to hold the coated magnetite particles in suspension in the ink.

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Process for Monitoring Ink Characteristics

Magnetic inks suitable for use with ink jet printing frequently cause clogging of the small diameter orifices through which they flow. Magnetic particles of 150 angstrom size are typically composed of magnetite encapsulated with ammonium oleate used to prevent agglomeration, retard particle growth and oxidation of the magnetite particles. Frequently, the ammonium oleate covers only portions of many of the magnetite particles that can result in agglomeration in a magnetic field. Accordingly, it is desirable to test the inks to determine whether they have satisfactory characteristics. Surfactants tend to hold the coated magnetite particles in suspension in the ink.

This technique monitors magnetic ink characteristics with time and is the basis of high-yield reproducible synthesis of these inks.

An upright tube 15.2 cm long and 0.6 cm i.-d. is filled with ink and passed through a toroidal solenoid. The concentration-versus-depth profile of the subject ink is then plotted, as shown, as depth in the tube vs. percent of change of inductance Delta L/L from which one can obtain the magnetic moment. The measurement automatically monitors the percent change of inductance L of a solenoid with and without an ink sample, i.e., Delta L over L approximately = X', where X' is the real part of the susceptibility and is proportional to the magnetite particle concentration.

Application of a uniform magnetic field for varying periods of tim...