公开(公告)号：CA1162228A

公开(公告)日：1984-02-14

申请号：CA352830

申请日：1980-05-27

Applicant: IBM

Inventor： CUNNINGHAM EARL A ,  CUTSHALL DAVID E ,  HEILING GERALD M ,  SODERSTROM RONALD L ,  THOMPSON JAMES M

IPC: B41J2/36 ,  B41J2/365 ,  B41M5/26

Abstract: A driver circuit for a thermal printing element varies the power applied to the element, depending upon its recent history of energization, in order to maintain uniform print density desprite temperature variation in the element. A capacitor charges and discharges to measure time intervals since the last element energization to control the voltage applied by an output transistor.