TRIMMING FOR RESISTANCE VALUE OF THERMAL HEAD HEATING RESISTOR

摘要

PURPOSE:To obtain a thermal head having a heating element of a small distribution in resistance value, by a method wherein trimming is advanced calculating the variation of the resistance value of a heating resistor. CONSTITUTION:Resistance values of all dots are measured by using a multi- meter 5 and a trimming target resistance value is determined from the result of measurement. Then, pulse conditions and power to be applied to each dot are set. Trimming is executed on each dot by selection of a multi-scanner 4 and a change on standing of the resistance value of the dot during trimming is simultaneously measured. The waveforms of voltage at both ends of a standard resistor 9 is recorded with a signal analyser 6 while a trimming impulse is applied and their crest values are at any time taken in a controller 1. A current value flowing to the dot is obtained and the resistance value is calculated from an impressed voltage. By selection of conditions for comparing the target resistance value at the controller 1 with the resistance value calculated from data taken in from the signal analyser 6, trimming can be executed highly accurately.