Printer with active fluidic architecture

Abstract

A inkjet printer that has an ink supply (112), a printhead integrated circuit (IC) (74) in fluid communication with the ink supply via an upstream ink line (67), the printhead IC (74), a waste ink outlet in fluid communication with the printhead IC (74) via a downstream ink line (106), an upstream shut off valve (138) in the upstream ink line (67), and, a downstream pump mechanism (114) in the downstream ink line. With a valve upstream of the printhead and a pump downstream of the printhead, the user has active control of the ink flow upstream, downstream or in the printhead IC. In the event that problems such as ink flooding, color mixing or printhead depriming occur, the user can follow simple troubleshooting protocols to rectify the situation.

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 shows a top perspective view of a prior art printhead assembly;

FIG. 2 shows an exploded view of the printhead assembly shown in FIG. 1;

FIG. 3 shows an inverted exploded view of the printhead assembly shown in FIG. 1;

FIG. 4 shows a cross-sectional end view of the printhead assembly of FIG. 1;

FIG. 5 shows a magnified partial perspective view of the drop triangle end of a printhead integrated circuit module as shown in FIGS. 2 to 4;

FIG. 6 shows a magnified perspective view of the join between two printhead integrated circuit modules shown in FIGS. 2 to 5;

FIG. 7 shows an underside view of the printhead integrated circuit shown in FIG. 5;

FIG. 8 shows a transparent top view of a printhead assembly of FIG. 15 showing in particular, the ink conduits for supplying ink to the printhead integrated circuits;

FIG. 9 is a partial enlargement of FIG. 8;

FIG. 10 is an enlarged view of gas bubbles in the conduits of the LCP moulding;

FIG. 11 is a sketch of the artifacts that can result from bubble contamination of the ink lines;

FIG. 12A is a sketch of the LCP moulding and the printhead IC in a fluidic system of the prior art;

FIG. 12B is a sketch showing the ink line bifurcations in the prior art fluidic system;

FIG. 13A is a sketch of the LCP moulding and the printhead IC in a fluidic system of the present invention;

FIG. 13B is a sketch showing the ink line bifurcations in the fluidic system of the present invention;

FIG. 14 is a schematic cross section of the LCP moulding and the printhead IC in a fluidic system of the present invention;

FIGS. 15A to 15C show the LCP conduit profiling for passive bubble control;

FIGS. 16 to 21 show the various unit operations that are possible with the active control provided by the present invention;

FIG. 22 shows a single pump/four valve implementation of the fluidic system;

FIG. 23 shows a single pump/two valve implementation of the fluidic system;

FIG. 24 is a sketch of another single pump fluidic system;

FIGS. 25A and 25B schematically show the fluidic system FIG. 24 and the initial priming of the printhead IC;

FIGS. 26A to 26E schematically show the operational stages of the fluidic system FIG. 24 moving from standby to print ready mode;

FIGS. 27A and 27B schematically show the fluidic system FIG. 24 moving to a long term power down mode/move printer mode;

FIGS. 28A and 28C schematically show the fluidic system FIG. 24 recovering from long term power down/deprime/gross color mixing;

FIG. 29 is a perspective view of a shut off valve; and,

FIG. 30 is a partial section view of the shut off valve.

Claims

1. An inkjet printer comprising: an ink supply;a printhead integrated circuit (IC) in fluid communication with the ink supply via an upstream ink line, the printhead IC having an array of nozzles each with respective actuators for ejecting drops of ink onto print media;a waste ink outlet in fluid communication with the printhead IC via a downstream ink line;an upstream shut off valve in the upstream ink line; and,a downstream pump mechanism in the downstream ink line.

2. An inkjet printer according to claim 1 wherein the pump mechanism is reversible for pumping ink toward the waste ink outlet or toward the ink manifold.

3. An inkjet printer according to claim 2 wherein the pump mechanism is a peristaltic pump.

4. An inkjet printer according to claim 1 further comprising a pressure regulator upstream of the printhead IC for maintaining ink in the nozzles at a hydrostatic pressure less than atmospheric pressure.

5. An inkjet printer according to claim 4 wherein the ink supply is an ink tank upstream of the shut off valve, and the pressure regulator is positioned in the ink tank.

6. An inkjet printer according to claim 5 wherein the pressure regulator is a bubble point regulator which has an air bubble outlet submerged in the ink in the ink tank, and an air inlet vented to atmosphere such that any reduction of hydrostatic pressure in the in the ink tank because of ink consumption draws air through the air inlet to form bubbles at the bubble outlet and keep the pressure in the ink tank substantially constant.

7. An inkjet printer according to claim 5 further comprising a filter upstream of the printhead IC for removing particulates from the ink.

8. An inkjet printer according to claim 7 wherein the ink tank has an outlet in sealed fluid communication with the shut off valve and the filter is positioned in the ink tank, covering the outlet.

9. An inkjet printer according to claim 5 wherein the ink tank is a removable ink cartridge and the outlet can releasably engage the upstream ink line.

10. An inkjet printer according to claim 1 wherein the shut off valve is biased shut and returns to its shut position when the printer is powered down.

11. An inkjet printer according to claim 6 wherein the shut off valve displaces ink when moving to its shut position such that when the shut off valves opens, a finite volume of ink is drawn away from the ink tank to drop the hydrostatic pressure at the bubble outlet toward the bubble point pressure.

12. An inkjet printer according to claim 1 further comprising a capper that is movable between an unsealed position spaced from the nozzles of the printhead IC and a sealed position creating an air tight seal over the nozzles.

13. An inkjet printer according to claim 12 wherein the array of nozzles is formed in a nozzle plate and the capper is configured to remove ink and particulates deposited on the nozzle plate.

14. An inkjet printer according to claim 1 further comprising a sensor downstream of the printhead IC for sensing the presence or absence of ink.

15. An inkjet printer according to claim 14 wherein the sensor is upstream of the peristaltic pump.

16. An inkjet printer according to claim 2 comprising a plurality of the ink tanks for separate ink colors, and a plurality of upstream ink lines and downstream ink lines for each colour respectively, wherein the peristaltic pump is a multi-channel peristaltic pump that can pump each ink color simultaneously.

17. An inkjet printer according to claim 14 further comprising a controller operatively linked to the sensor and the peristaltic pump such that the controller operates the pump in response to output from the sensor.

18. An inkjet printer according to claim 1 further comprising an electronic controller operatively connected to the shut off valve and the pump for selectively priming and depriming the printhead IC.

19. An inkjet printer according to claim 14 further comprising an electronic controller operatively connected to the shut off valve, the sensor and the pump for selectively priming and depriming the printhead IC.

20. An inkjet printer according to claim 12 further comprising an electronic controller operatively connected to the shut off valve, the capper and the pump for selectively priming and depriming the printhead IC.