Operating temperature and the thermal ink jet print head which raises thermal efficiency

摘要

An ink jet printhead (10) for deposit ink droplets ON a record medium ON demand, comprises upper and lower substrates (28,31) and each having at least one substantially-flat surface (16,22). The substrates are bonded together with a thick film layer (18) sandwiched therebetween. The flat surface of the upper substrate has in it a set of parallel, closed-end channels for subsequent use as ink flow channels (20) and a separate associated recess (38) for subsequent use as an ink manifold for supplying ink to the set of channels. The flat surface of the lower substrate has an array of heater elements (34) and addressing electrodes (33,35) formed thereon. The thick film layer is deposited ON the surface of the lower substrate and over the heater elements (34) and addressing electrodes and patterned, prior to the mating of the substrates, to remove predetermined portions of the thick film layer, thus forming an ink flow path in the thick film layer between the channels and the manifold, and forming a set of individual and parallel trenches (26) open at one end. The trenches expose each heater element and extend to the edge of the lower substrate to form the open end (27). After the substrates are mated, the open ends of the trenches serve as droplet-emitting nozzles, and the closed ends serve as back walls (41) to prevent lateral bubble growth in that direction, while the closed ends of the channels inhibit lateral bubble growth towards the nozzles and concurrently provide additional ink capacity above the heater elements. IMAGE