Patent ID: 6345883
Filing Date: 2002-02-12
Classification: B41J

Abstract:
In a thermal-compression type ink jetting apparatus comprising:a nozzle module having an ink chamber for reserving ink, and a nozzle hole in the ink chamber for permitting ink to be jetted therethrough; a driving module adjacent to the nozzle module, said driving module having a working fluid chamber charged with the working fluid, and an electric heater disposed in the working fluid chamber for heating fluid in the working fluid chamber; and a membrane between the ink chamber and the working fluid chamber, the membrane adapted to be pressed into the ink chamber by pressure of a bubble formed when the heater heats the working fluid and thereby jets the ink in the ink chamber through the nozzle hole; the improvement comprising: a plurality of fin elements disposed on the heater for conducting heat away from the heater, said fin elements disposed in a manner such that they force bubble formation in the working fluid chamber to occur as formation of a plurality of small bubbles which disappear rapidly rather than as formation of a single large bubble which disappears slowly.