Investigation to minimize heater burnout in thermal thin film print heads

Abstract

A test system to improve the reliability of a printhead was developed and various printheads was tested. We developed a thermally driven monolithic inkjet printhead comprising dome-shaped ink chambers, thin film nozzle guides and omega-shaped heaters integrated on the top surface of each chamber. In a durability test of an inkjet printhead, the test system automatically detects a heater failure using a Wheatstone bridge circuit. Various models were designed and tested to develop a more reliable printhead. Three design parameters of the thickness of heat-transmission layer, reinforcement layer, and insulation layer were investigated in the test. Specially, the reinforcement layer was introduced to improve the lifetime of printhead. The thicker the heat-transmission layer as well as the insulation layer, the longer the life of the printhead. The lifetime of a heater with a reinforcement layer was longer than the lifetime of a heater without a reinforcement layer.