by compensation for variation in current

Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed > characterised by selective application of heat to a heat sensitive printing or impression-transfer material > using thermal heads > providing current or voltage to the thermal head > Control circuits for heating-element selection > Print density control > by compensation for variation in current

Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed (mounting, arrangement or disposition of types or dies B41J1/00) > characterised by selective application of heat to a heat sensitive printing or impression-transfer material (B41J2/385, B41J2/435 take precedence) > using thermal heads > providing current or voltage to the thermal head > Control circuits for heating-element selection > Print density control > by compensation for variation in current