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High Resistivity Ribbon for High Speed Printing

IP.com Disclosure Number: IPCOM000038623D
Original Publication Date: 1987-Feb-01
Included in the Prior Art Database: 2005-Jan-31
Document File: 2 page(s) / 23K

Publishing Venue

IBM

Related People

Chieu, TC: AUTHOR [+5]

Abstract

In conventional resistive ribbon thermal transfer printing, the sheet resistivity of the carbonloaded resistive polycarbonate layer (approximately l7 mm thick) is in the range of 400-500 ohms per square. The print current needed to obtain an ink temperature between electrodes of about 200ŒC at conventional printing speeds is about 26 ma. At higher speeds, the printing current required to produce this ink temperature is increased significantly. This very high current can cause very high head temperatures and wear problems. A simple ribbon structure that can be used for high speed printing at much lower printing currents is shown. The ribbon consists of a high resistivity carbon-loaded polycarbonate layer l0 having a sheet resistivity in the range of about 2000 ohms per square.

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High Resistivity Ribbon for High Speed Printing

In conventional resistive ribbon thermal transfer printing, the sheet resistivity of the carbonloaded resistive polycarbonate layer (approximately l7 mm thick) is in the range of 400-500 ohms per square. The print current needed to obtain an ink temperature between electrodes of about 200OEC at conventional printing speeds is about 26 ma. At higher speeds, the printing current required to produce this ink temperature is increased significantly. This very high current can cause very high head temperatures and wear problems. A simple ribbon structure that can be used for high speed printing at much lower printing currents is shown. The ribbon consists of a high resistivity carbon-loaded polycarbonate layer l0 having a sheet resistivity in the range of about 2000 ohms per square. This corresponds to a carbon loading of about 20% in the polycarbonate. A thin coating l2 about 500 ~ thick and having a resistivity of about 0.0l5 ohm-cm is deposited on the surface of the ribbon to reduce contact resistance. A suitable coating material is CrN, which can be easily deposited by sputtering. The ribbon also includes an Al current-return layer l4 having a thickness of about l000 ~ and the ink layer l6. A 500 ~ thick CrN layer with sheet resistivity of about 3000 ohms per square has been deposited on the surface of a high resistivity polycarbonate ribbon about l7 mm thick having a sheet resistivity of about l850 ohms per square. T...