Temperature control for an ink jet printhead

Abstract From the Canadian patent

In a printhead die-bonded to a substrate a recess, in a preferred, embodiment, is formed in the substrate and layers of resistive material separated by a dielectric layer are formed in the recess by a thick film screen print process. The recess underlies the printhead which remains bonded to the substrate along the edges of the recess. This arrangement provides good proximity of the heater and the temperature sensor to the printhead enabling measurements to be made and sent to a control circuit which regulates heater operation to maintain the printhead within a desired operating range. The configuration also allows precise positioning of the printhead with the metal surface as a reference.