Switching Driver Circuit for Resistive Ribbon Thermal Transfer Printing
Original Publication Date: 1987-Aug-01
Included in the Prior Art Database: 2005-Feb-01
In order to print with resistive ribbon thermal transfer technology, current is injected into the ribbon from a line of electrodes, causing the ribbon to become heated in the region of current injection and thereby melting a thin layer of ink coated on the ribbon. The molten ink is pressed into the paper by the printhead, producing the desired print on the paper. Current is supplied to the print electrodes by either constant current or constant power circuits. In order to control either the current or the power, the circuit itself consumes an amount of power similar to that needed by the ribbon in order to print. That is, the circuits provide control, but are inherently wasteful. The extra power required appears as heat in the circuitry and is undesirable from a cost point of view.