Method of minimizing nozzle drooling during printhead priming
View Patent ↗A method of priming a printhead whilst minimizing nozzle drooling, the method comprising the steps of: (i) providing a printhead comprising: an ink distribution manifold having an ink inlet and an ink outlet; and one or more printhead integrated circuits mounted on the manifold, each printhead integrated circuit comprising a plurality of nozzles; (ii) providing an ink chamber in fluid communication with the ink inlet; and (iii) applying a positive pressure at the ink inlet whilst simultaneously applying a negative pressure at the ink outlet so as to draw ink through the manifold and prime the printhead whilst minimizing nozzle drooling.
1. A method of priming a printhead whilst minimizing nozzle drooling, said method comprising the steps of:
(i) providing a printhead comprising:
an ink distribution manifold having an ink inlet and an ink outlet; and
one or more printhead integrated circuits mounted on said manifold, each printhead integrated circuit comprising a plurality of nozzles;
(ii) providing an ink chamber in fluid communication with said ink inlet; and
(iii) applying a positive pressure at said ink inlet whilst simultaneously applying a negative pressure at said ink outlet so as to draw ink through said manifold and prime said printhead whilst minimizing nozzle drooling.
2. The method of claim 1 , wherein said printhead is a pagewidth inkjet printhead.
3. The method of claim 1 , wherein said positive pressure is applied by positively pressurizing a headspace above ink in said ink chamber.
4. The method of claim 3 , wherein said positive pressure is applied using a pump having a pump outlet communicating with said headspace.
5. The method of claim 4 , wherein a pump inlet communicates with said ink outlet so as to apply said negative pressure at said ink outlet.
6. The method of claim 5 , wherein a downstream ink line is connected to said ink outlet, and said method further comprises the steps of:
monitoring for the presence of ink in said downstream ink line; and
shutting off said pump when ink is sensed in said downstream ink line.
7. The method of claim 6 , wherein an optical sensor is provided for sensing said ink in said downstream ink line.
8. The method of claim 7 , wherein phantom sensing of ink caused by ink bubbles in said downstream ink line is minimized.
9. The method of claim 8 , wherein phantom sensing of ink is minimized by sensing for ink above a bubble-bursting point in a bubble-bursting chamber provided in said downstream ink line.
10. The method of claim 9 , wherein said bubble-bursting chamber is in fluid communication with an air outlet, said air outlet being in fluid communication with a pump inlet.