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Water-Dispersed Resistive Ribbon Ink

IP.com Disclosure Number: IPCOM000060208D
Original Publication Date: 1986-Mar-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Johnson, JR: AUTHOR [+3]

Abstract

Resistive transfer mediums of the general kind described in U.S. Patent 4,320,170 have a resistive layer serving as a substrate to an ink layer, which is a heat-flowable marking material. A very thin layer of aluminum separates the resistive layer and the ink layer. Current is applied to the resistive layer from electrodes in a printhead, and the resulting electrical heating causes the marking material to flow. A water-based ink is employed, containing ammonium abietate, a fugitive base, as a dispersant. A water-based ink eliminates pollution and recovery problems associated with organic solvents. The ink contains dispersed polymers and carbon black. Such water dispersions contain dispersing agents for stabilization. The dispersing agents have no function during use of the ribbon.

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Water-Dispersed Resistive Ribbon Ink

Resistive transfer mediums of the general kind described in U.S. Patent 4,320,170 have a resistive layer serving as a substrate to an ink layer, which is a heat-flowable marking material. A very thin layer of aluminum separates the resistive layer and the ink layer. Current is applied to the resistive layer from electrodes in a printhead, and the resulting electrical heating causes the marking material to flow. A water-based ink is employed, containing ammonium abietate, a fugitive base, as a dispersant. A water-based ink eliminates pollution and recovery problems associated with organic solvents. The ink contains dispersed polymers and carbon black. Such water dispersions contain dispersing agents for stabilization. The dispersing agents have no function during use of the ribbon. A potassium salt of rosin acid has been used as such a dispersant. This salt absorbs about 30% of its weight in water under humid conditions. An ink containing this salt absorbs moisture under humid conditions largely because of this salt. The ink dispersion with this salt is highly basic (pH of 10.1 + 0.2 is typical). Rewetting the dried ink with humidity restores the high pH, and the aluminum underlayer is corroded by the active base. Replacement of the potassium salt with ammonium abietate showed a 4 to 1 reduction in percent weight between vacuum dry and stabilization at 82 degrees F and 80% relative humidity. Similarly, at the same increased tem...