Printhead with side entry ink chamber
View Patent ↗An inkjet printhead with an array of elongate ink chambers, each having a nozzle, an actuator for ejecting ink through the nozzle and a sidewall opening allowing ink to refill the chamber; wherein, the opening is in one of the long sides of the ink chamber. Configuring the ink chambers so that they have side inlets reduces the ink refill times. The inlets are wider and therefore refill flow rates are higher.
1. An inkjet printhead comprising:
an elongate ink conduit; and
an array of ink chambers, each ink chamber having an elongate shape defined by two relatively long sidewalls and two relatively short sidewalls, a roof supported by the sidewalls and a chamber floor, the relatively long sidewalls being parallel to the elongate ink conduit, each ink chamber comprising:
a nozzle in the roof of the ink chamber;
an elongate thermal actuator arranged parallel to the elongate ink conduit for ejecting ink through the nozzle; and
a sidewall opening allowing ink to refill the chamber from the elongate ink conduit, the sidewall opening being in one of the relatively long sidewalls of the ink chamber,
wherein ink from the elongate ink conduit refills each of the ink chambers in the array of ink chambers.
2. An inkjet printhead according to clam 1 further comprising drive circuitry for selectively providing the thermal actuators with drive signals, wherein each thermal actuator is a unitary planar structure.
3. An inkjet printhead according to claim 2 wherein the drive circuitry has a drive field effect transistor (FET) for each of the thermal actuators, the drive voltage of the drive FET being less than 5 Volts.
4. An inkjet printhead according to claim 3 wherein the drive voltage of the drive FET is 2.5 Volts.
5. An inkjet printhead according to claim 4 wherein the nozzle plate has an exterior surface with formations for reducing its co-efficient of static friction.
6. An inkjet printhead according to claim 1 wherein each of the ink chambers have a plurality of nozzles formed over the thermal actuator; wherein during use,
the thermal actuator simultaneously ejects ink through all the nozzles of the ink chamber.
7. An inkjet printhead according to claim 6 wherein each of the ink chambers has two nozzles.
8. An inkjet printhead according to claim 6 wherein the nozzles in each ink chamber are arranged in a line parallel to the length of the thermal actuator.
9. An inkjet printhead according to claim 6 wherein the nozzles are elliptical.
10. An inkjet printhead according to claim 9 wherein the major axes of the elliptical nozzles are aligned.
11. An inkjet printhead according to claim 1 wherein each of the ink inlets has an ink permeable trap and a vent sized so that the surface tension of an ink meniscus across the vent prevents ink leakage; wherein during use,
the ink permeable trap directs gas bubbles to the vent where they vent to atmosphere.
12. An inkjet printhead according to claim 1 further comprising a filter structure at the opening of each ink chamber, the filter structure having rows of obstructions extending transverse to the flow direction through the opening, the obstructions in each row being spaced such that they are out of registration with the obstructions in an adjacent row with respect to the flow direction.
13. An inkjet printhead according to claim 1 wherein the nozzles are arranged in rows such that the nozzle centres are collinear and the nozzle pitch along each row is greater than 1000 nozzles per inch.