Printhead de-priming system with float valve isolation of printhead from ink reservoir
View Patent ↗A printhead depriming system, the system comprising: an ink reservoir; an ink chamber positioned below the ink reservoir, the ink chamber comprising an outlet port connected to an ink inlet of the printhead via an upstream ink line, an inlet port connected to the ink reservoir, and a float valve configured for closing the inlet port; and an air pump communicating with a headspace above the ink in the ink chamber, such that actuation of the air pump generates a negative pressure in the headspace and draws ink from the printhead into the ink chamber so as to de-prime the printhead, wherein an increased level of ink in the ink chamber during the de-priming causes concomitant shutting of the float valve and isolates the ink reservoir from the printhead.
1. A printhead depriming system, said system comprising:
an ink reservoir;
an ink chamber positioned below said ink reservoir, said ink chamber comprising an outlet port connected to an ink inlet of a printhead via an upstream ink line, an inlet port connected to said ink reservoir, and a float valve configured for closing said inlet port; and
an air pump communicating with a headspace above said ink in said ink chamber, such that actuation of said air pump generates a negative pressure in said headspace and draws ink from said printhead into said ink chamber so as to de-prime said printhead,
wherein an increased level of ink in said ink chamber during said de-priming causes concomitant shutting of said float valve and isolates said ink reservoir from said printhead.
2. The depriming system of claim 1 , wherein said printhead is positioned above said ink chamber.
3. The depriming system of claim 1 further comprising a downstream ink line connected to an ink outlet of said printhead, wherein ink is drawn from said downstream ink line, through said printhead and towards said ink chamber during said de-priming.
4. The depriming system of claim 3 , wherein said downstream ink line is in fluid communication with said air pump, thereby enabling both pushing and pulling of ink through said printhead during said depriming.
5. The depriming system of claim 1 , wherein said pump is reversible for effecting both de-priming and priming operations.
6. The depriming system of claim 5 , wherein a check valve is positioned between said ink reservoir and said ink chamber for isolating said ink reservoir from said printhead during a priming operation.
7. The depriming system of claim 1 , wherein said float valve comprises:
an arm pivotally mounted about a pivot;
a float mounted at one end of said arm; and
a valve head mounted at an opposite end of said arm,
wherein said valve head is positioned for sealing engagement with a valve seat at said inlet port.
8. The depriming system of claim 1 , wherein said ink chamber is a pressure-regulating chamber for regulating a hydrostatic pressure of ink supplied to said printhead during normal printing.
9. The depriming system of claim 1 , which is configured for use with a replaceable pagewidth printhead.
10. The depriming system of claim 1 , wherein said printhead comprises one or more printhead integrated circuits mounted on an ink distribution manifold, each printhead integrated circuit comprising a plurality of nozzles, and said manifold having said ink inlet and an ink outlet.
11. A printer comprising:
an inkjet printhead having an ink inlet and a plurality of nozzles; and
a printhead depriming system, said depriming system comprising:
an ink reservoir;
an ink chamber positioned below said ink reservoir, said ink chamber comprising an outlet port connected to said ink inlet via an upstream ink line, an inlet port connected to said ink reservoir, and a float valve configured for closing said inlet port; and
an air pump communicating with a headspace above said ink in said ink chamber, such that actuation of said air pump generates a negative pressure in said headspace and draws ink from said printhead into said ink chamber so as to de-prime said printhead,
wherein an increased level of ink in said ink chamber during said de-priming causes concomitant shutting of said float valve and isolates said ink reservoir from said printhead.
12. The printer of claim 11 , wherein said printhead is positioned above said ink chamber.
13. The printer of claim 11 further comprising a downstream ink line connected to an ink outlet of said printhead, wherein ink is drawn from said downstream ink line, through said printhead and towards said ink chamber during said de-priming.
14. The printer of claim 11 , wherein said downstream ink line is in fluid communication with said air pump, thereby enabling both pushing and pulling of ink through said printhead during said depriming.
15. The printer of claim 11 , wherein said pump is reversible for effecting both de-priming and priming operations.
16. The printer of claim 15 , wherein a check valve is positioned between said ink reservoir and said ink chamber for isolating said ink reservoir from said printhead during a priming operation.
17. The printer of claim 11 , wherein said float valve comprises:
an arm pivotally mounted about a pivot;
a float mounted at one end of said arm; and
a valve head mounted at an opposite end of said arm,
wherein said valve head is positioned for sealing engagement with a valve seat at said inlet port.
18. The printer of claim 11 , wherein said ink chamber is a pressure-regulating chamber for regulating a hydrostatic pressure of ink supplied to said printhead during normal printing.
19. The printer of claim 11 , wherein said printhead is a replaceable pagewidth printhead.
20. The printer of claim 11 , wherein said printhead comprises one or more printhead integrated circuits mounted on an ink distribution manifold, each printhead integrated circuit comprising a plurality of nozzles, and said manifold having said ink inlet and an ink outlet connected to a downstream ink line.