Resistive Ribbon Printhead Drive
Original Publication Date: 1983-Aug-01
Included in the Prior Art Database: 2005-Feb-07
U.S. Patent 4,345,845 discloses a resistive ribbon printhead current-control system. In such a system, electrical signals are applied by forty printhead electrodes wiping across an outer, resistive layer of the ribbon. These signals migrate inwardly to a highly conductive, aluminum layer, with localized heating occurring in the process. The foregoing patent teaches a monitoring contact spaced from the printhead in a direction opposite a grounding contact. In the circuit shown, the voltage is level shifted and applied (as VD) to a drive line. That voltage is referenced to a level-defining signal, and the difference of those signals is applied across a resistor for each electrode.