Printhead cartridge valve assembly with diaphragm pressure regulator

1. A valve assembly for a printhead cartridge, said valve assembly comprising:

an inlet valve for engaging with an outlet valve of an ink cartridge, the inlet valve having a conical structure defining an inlet opening at a top thereof;

a valve seat defined on an inner surface of the conical structure;

a depressible valve member provided within the inlet valve, the depressible valve member being normally biased against the valve seat to form therewith a fluidic seal;

a skirt engaging portion defined on the inner surface of the conical structure above the valve seat, the skirt engaging portion for engaging a resilient skirt of the ink cartridge, and

a pressure regulator provided below the depressible valve member, the pressure regulator having a diaphragm and a regulator inlet defined through the diaphragm, the regulator inlet for facilitating flow of ink from a valve-side of the diaphragm to a printhead-side, wherein

the skirt engaging portion is dimensioned to engage the resilient skirt of the ink cartridge simultaneously with an engagement of a valve stem of the ink cartridge with the depressible valve member.

2. The valve of claim 1 , further comprising an ink filter provided between the depressible valve member and the diaphragm, said ink filter extending beyond a radial extent of the valve member.

3. The valve of claim 1 , wherein the pressure regulator includes a spring configured to bias the regulator inlet into a closed position.

4. The valve of claim 3 , wherein hydrostatic pressure of ink in the ink cartridge acts on an upstream side of the diaphragm, and static ink pressure acts on a downstream side of diaphragm, and the regulator inlet is actuated between an open and closed by a pressure differential between the hydrostatic pressure and a combination of the static pressure and spring bias.

5. The valve of claim 4 , wherein extraction of ink through the regulator inlet lowers a hydrostatic pressure of the ink on the downstream side of the diaphragm.

6. The valve assembly of claim 1 , wherein the regulator inlet is normally biased against a central hub formed on an underside of the depressible valve member to prevent fluidic communication from the valve-side and print-head side of the pressure regulator.

7. The valve of claim 6 , wherein when a pressure exerted against the diaphragm by ink on the print-head side of the diaphragm together with the force exerted by the spring is less than a pressure exerted against the diaphragm by ink on the valve-set of the diaphragm, the regulator inlet is adapted to move away from the central hub to permit ink flow through the regulator inlet and to establish fluid pressure equalization on both sides of the diaphragm so that the bias of the spring reseals the regulator inlet against the central hub.

8. The valve of claim 7 , wherein continued extraction of ink through the regulator inlet results in the regulator inlet successively being biased against and away from the central hub as a pressure difference across the diaphragm oscillates about a threshold pressure difference required to balance a force of the spring.

9. The valve assembly of claim 8 , wherein the regulator inlet is configured to be biased away from the central hub by a pressure head exerted by ink above the pressure regulator.

10. The valve assembly of claim 8 , wherein the regulator inlet is biased against the central hub partially by a spring and partially a pressure differential between ink below the pressure regulator and ink above the pressure regulator.