Ink jet printhead with polarity-changing driver for thermal resistors
An ink jet printhead device includes a substrate and a plurality of thermal resistors on the substrate. Each thermal resistor includes first and second electrodes and a resistive layer extending therebetween. A polarity-changing driver is coupled to the plurality of thermal resistors and configured to change a driving polarity between the first and second electrodes of each of the plurality of thermal resistors.
1. An ink jet printhead device comprising:
a substrate;
a plurality of thermal resistors on said substrate, each thermal resistor comprising first and second electrodes and a resistive layer extending therebetween; and
a polarity-changing driver coupled to said plurality of thermal resistors and configured to change a driving polarity between the first and second electrodes of each of said plurality of thermal resistors, wherein said polarity-changing driver is configured to change a voltage polarity so that said first electrode is at a voltage reference at a first polarity and said second electrode is at the voltage reference in a second polarity.
2. The ink jet printhead device according to claim 1 wherein said polarity-changing driver is configured to periodically reverse a driving voltage polarity.
3. The ink jet printhead device according to claim 1 wherein said polarity-changing driver is configured to generate a series of pulse trains.
4. The ink jet printhead device according to claim 3 wherein said polarity-changing driver comprises a counter configured to reverse the polarity based upon a count of the series of pulse trains.
5. The ink jet printhead device according to claim 3 wherein said polarity-changing driver is configured to generate the series of pulse trains in alternating polarity.
6. The ink jet printhead device according to claim 1 wherein said polarity-changing driver comprises an H-bridge.
7. The ink jet printhead device according to claim 6 wherein said H-bridge is on said substrate.
8. The ink jet printhead device according to claim 1 wherein each of said first and second electrodes comprises at least one of copper and aluminum.
9. The ink jet printhead device according to claim 1 wherein said resistive layer comprises at least one of tantalum and aluminum.
10. The ink jet printhead device according to claim 1 , wherein said polarity-changing driver is configured to change a positive driving voltage polarity.