Fluid ejection device with overlapping firing chamber and drive FET
View Patent ↗A fluid ejection device with a firing chamber from which fluid is ejected, a heating element that heats fluid in the firing chamber and, drive circuitry for the heating element having a field effect transistor (FET). At least part of the firing chamber overlaps the FET when viewed in a direction parallel to the direction of fluid ejection, and the firing chamber and the FET is separated by a layer of insulating material.
1. A fluid ejection device comprising:
a firing chamber from which fluid is ejected;
a heating element that heats fluid in the firing chamber; and,
drive circuitry for the heating element having a field effect transistor (FET), wherein,
at least part of the firing chamber overlaps the FET when viewed in a direction parallel to the direction of fluid ejection, and the firing chamber and the FET is separated by a layer of insulating material.
2. The device of claim 1 further comprising a substrate having a first surface, wherein the drive circuitry and the heating element are positioned over the first surface of the substrate, wherein the substrate further has a conductive via electrically coupled with the heating element, the conductive via extending through the insulating layer.
3. The device of claim 2 wherein the FET is positioned between about 1 and 30 microns from the heating element.
4. A printing system comprising:
a fluid reservoir;
a printhead having a plurality of fluid firing chambers each with a heating resistor and associated drive circuitry positioned; wherein,
at least one fluid firing chamber overlaps with the respective drive circuitry for the heating resistor when viewed from a direction parallel to a direction in which the fluid is ejected from the fluid firing chamber.
5. The printing system of claim 4 wherein each fluid heating resistor is arranged in a staggered fashion along the substrate.