High Resistivity Ribbon for High Speed Printing
Original Publication Date: 1987-Feb-01
Included in the Prior Art Database: 2005-Jan-31
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.