Fluidically controlled inkjet printhead

Abstract

An inkjet printer that has a printhead IC with and array of ink ejection nozzles, an ink manifold for distributing ink to the printhead IC, the ink manifold having an ink inlet and an ink outlet, an upstream pump in fluid communication with the ink inlet, and a downstream pump in fluid communication with the ink outlet. The upstream pump and the downstream pump are independently operable.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention will now be described by way of example only with reference to the accompanying drawings, in which:

FIG. 1 is a top and side perspective of a printhead assembly using a LCP ink manifold according to the prior art;

FIG. 2 is an exploded perspective of the printhead assembly shown in FIG. 1;

FIG. 3 is the exploded perspective of FIG. 2 shown from below;

FIG. 4 is transverse section through the printhead assembly of FIG. 1;

FIG. 5 shows a magnified partial perspective view of the bottom of the drop triangle end of a printhead integrated circuit module;

FIG. 6 shows a magnified perspective view of the join between two printhead integrated circuit modules;

FIG. 7 shows a magnified partial perspective view of the top of the drop triangle end of a printhead integrated circuit module;

FIG. 8 is a partial bottom view of the LCP manifold and the printhead IC;

FIG. 9 is an enlarged partial bottom view of the LCP manifold and the printhead IC;

FIG. 10 shows the fine conduits in the underside of the LCP manifold;

FIG. 11 shows the typical artifacts from outgassing bubbles forming in the LCP manifold and the printhead IC;

FIG. 12 is a sketch of the fluidic system for a prior art printer;

FIG. 13 is a sketch of a dual pump embodiment of the active fluidic system of the present invention; and,

FIG. 14 is a sketch of a single pump embodiment of the active fluidic system of the present invention.

Claims

1. An inkjet printer comprising: a printhead IC with and array of ink ejection nozzles;an ink manifold for distributing ink to the printhead IC, the ink manifold having an ink inlet and an ink outlet;an upstream pump in fluid communication with the ink inlet; and,a downstream pump in fluid communication with the ink outlet; wherein,the upstream pump and the downstream pump are independently operable.

2. An inkjet printer according to claim 1 further comprising a gas inlet that can be opened to establish fluid communication between the ink manifold and a supply of gas, and can be closed to form a gas tight seal; such that, the ink manifold can be primed with ink when the gas inlet is closed, and de-primed of ink when the gas inlet is open.

3. An inkjet printer according to claim 2 further comprising an ink supply connected to the inlet of the ink manifold via an upstream ink line, and the downstream pump connected to the ink manifold via a downstream ink line.

4. An inkjet printer according to claim 3 wherein the gas inlet is an air inlet which can open to atmosphere.

5. An inkjet printer according to claim 1 wherein the hydrostatic pressure in the ink at the ink ejection nozzle is less than atmospheric.

6. An inkjet printer according to claim 1 wherein the upstream and downstream pumps are reversible for pumping fluid in a reverse direction.

7. An inkjet printer according to claim 4 wherein the downstream ink line connects the ink manifold to the ink supply via the downstream pump and the outlet of the ink manifold is in fluid communication with a gas vent for gas drawn into the ink manifold during depriming.

8. An inkjet printer according to claim 7 wherein the gas vent is in the ink supply.

9. An inkjet printer according to claim 1 the upstream and the downstream pumps are peristaltic pumps.

10. An inkjet printer according to claim 1 wherein the upstream pump and the downstream pump are provided by a six-way peristaltic pump head driven by a single motor, the six way pump head having two independently operable three way pump heads.

11. An inkjet printer according to claim 1 wherein the upstream pump and the downstream pump are driven by separate motors.

12. An inkjet printer according to claim 3 wherein the upstream ink line has a pressure regulator that allows ink to flow to the ink manifold at a predetermined threshold pressure difference across the pressure regulator.

13. An inkjet printer according to claim 1 further comprising a capping member for sealing the array of nozzles on the printhead IC.

14. An inkjet printer according to claim 1 wherein the printer is a color printer with a separate ink supplies for each ink color, and respective inlets and outlets for each ink color in the ink manifold.

15. An inkjet printer according to claim 1 wherein the printhead IC is a pagewidth printhead and the ink manifold is an elongate structure with the inlet at one end and the outlet at the opposite end.

16. An inkjet printer according to claim 3 wherein the upstream pump and the downstream pump can operate at different flow rates.

17. An inkjet printer according to claim 3 wherein the upstream pump and the downstream pump can act as shout off valves in the upstream and down stream lines respectively.

18. An inkjet printer according to claim 1 wherein the printer further comprises an ink filter upstream of the ink manifold for removing bubbles and contaminants from ink flowing to the manifold.