Controlled Power Printhead Driver for Resistive Ribbon
Original Publication Date: 1987-Feb-01
Included in the Prior Art Database: 2005-Jan-31
The instantaneous power going into a resistive ribbon is measured when used to control the average power to a desired level by a pulse-width modulation technique. The instantaneous power into the printing part of a resistive ribbon for each electrode is the product of the voltage across the printing part of the ribbon and the current into the electrode. The circuit includes a separate first portion for each electrode creating a pulse-width modulated (PWM) waveform having its duty cycle inversely proportional to the electrode current. A second portion of the circuit creates a PWM waveform having its (Image Omitted) duty cycle inversely proportional to the voltage across the printing part of the ribbon.