Patent ID: 7744195
Filing Date: 2010-06-29
Classification: B41J

Abstract:
1. An inkjet printhead comprising: an array of ink chambers formed on a wafer substrate, each having a nozzle aperture and a thermal actuator, the thermal actuator having a heater element extending between two contacts; CMOS (complementary metal-oxide semiconductor) drive circuitry formed by a plurality of flat, metal layers interleaved with interlayer dielectric for selectively providing the thermal actuators of the array with drive signals, the CMOS drive circuitry having a top-most metal layer providing electrodes for each of the thermal actuators respectively, the electrodes each having a flat surface, the contacts of each of the thermal actuators overlying the flat surfaces of the corresponding electrodes for face to face contacting engagement, the top-most metal layer also having apertures extending between each pair of the electrodes such that the heater element is suspended in the chamber; an ink conduit between a nozzle layer and the wafer substrate, the ink conduit being in fluid communication with a plurality of the ink chambers; and, a plurality of ink inlets extending through the wafer substrate for supplying the ink conduit, each of the ink inlets having an ink permeable trap and a vent sized so that the surface tension of an ink meniscus across the vent prevents ink leakage such that only gas bubbles vent to atmosphere through the vent; wherein, the contacts and the heater element are coplanar such that the thermal actuator is an integral planar structure.