Inkjet printhead with two-part body structure containing heater elements
View Patent ↗An inkjet printhead includes a “first part” wafer assembly. The wafer assembly defines an elongate ink supply channel and an ink inlet extending from the ink supply channel. A “second part” chamber roof layer is supported by the wafer assembly. The chamber roof layer defines an elongate ink conduit in fluid communication with the ink supply channel and nozzle chambers in fluid communication with the ink conduit. In addition, the chamber roof layer includes a row of nozzle apertures, aligned with the ink conduit and through which ink from nozzle chambers can be ejected. Heater elements contained within the two parts are suspended within nozzle chambers which, upon actuation, eject ink from the chambers out through the nozzle apertures.
1. An inkjet printhead comprising:
a wafer assembly defining an elongate ink supply channel and an ink inlet extending from the ink supply channel;
a chamber roof layer supported by the wafer assembly, the chamber roof layer defining an elongate ink conduit and nozzle chambers, the ink conduit being in fluid communication with the ink supply channel and the nozzle chambers being in fluid communication with the ink conduit;
a plurality of nozzle apertures defined through the chamber roof layer;
a plurality of heater elements on a floor of each nozzle chamber; and
a trench cut into the floor of each nozzle chamber in the vicinity of each heater element, the trench positioned with respect to the nozzle aperture to sandwich the heater element therebetween, whereby a level of the floor of the nozzle chamber in the vicinity of the heater element is lowered and ink supplied to the nozzle chamber immerses the heater element on both sides thereof, wherein
the ink conduit is substantially in the same plane as the nozzle chambers, the plane being parallel to the chamber roof layer.
2. An inkjet printhead as claimed in claim 1 , wherein the wafer assembly includes a CMOS drive circuitry layer and electrodes coupled to the drive circuitry layer.
3. An inkjet printhead as claimed in claim 2 , wherein the heater elements are each aligned in line with a respective nozzle aperture.
4. An inkjet printhead as claimed in claim 3 , wherein each heater element is substantially planar and rests on contacts provided at either end thereof
5. An inkjet printhead as claimed in claim 1 , wherein each heater element has a central void for minimizing the deleterious effects of cavitation forces during ink ejection.
6. An inkjet printhead as claimed in claim 1 , wherein the chamber roof layer defines a protruding nozzle rim, in turn, defining an endless recess.
7. An inkjet printhead as claimed in claim 1 , wherein the elongate ink supply channel and elongate ink conduit extend in a parallel direction of elongation normal to the ink inlet.