Firing frequency improvement of back shooting inkjet printhead by thermal management

This paper presents a firing frequency improvement of a backshooter type inkjet printhead, DomeJet, with an optimized thermal design. DomeJet is a thermally driven monolithic inkjet printhead that consists of dome-shaped ink chambers and omega-shaped heaters over the chambers. As the firing frequency increases, the residual heat accumulated in heater layer causes unstable droplet ejection. In a roofshooter architecture printhead, a silicon substrate with a layer of silicon dioxide between the substrate and the heater is an excellent thermal reservoir. Compared to a roofshooter, a backshooter type head has disadvantage in heat release since the heater is confined to a thin film which has low thermal conductivity. In this study, two models are proposed. Model I has an aluminum metal layer over the heater that forms heat passage to the substrate, and Model II has thick nickel nozzle plate in contact with the metal layer to enhance heat dissipation capability. The result gives a head being operated at a frequency of 40 kHz.