Original Publication Date: 1985-May-01
Included in the Prior Art Database: 2005-Feb-18
U. S. Patent 4,419,024 describes a resistive ribbon with an interlayer between the resistive substrate layer and a conductive metal layer of silicon dioxide. The silicon dioxide improves printing by functioning as a region of higher resistivity near the ink. An equivalent interlayer can be created by treating a resistive layer of resin and conductive filler with solvent and then expelling off the solvent. This displaces resin onto the surface and that resin layer exhibits high resistivity. A cast film of polycarbonate filled with conductive carbon black is transported to nipping rollers, one of steel and one of rubber. A minute layer of tetrahydrofuran, a polycarbonate solvent, is applied to the steel roll prior to its contact with the polycarbonate film.