Refill unit for an ink storage compartment connected to a printhead through an outlet valve

1. A refill unit for refilling an ink storage compartment for a printhead assembly, the ink storage compartment being fluidically connected to the printhead assembly via an outlet valve, the refill unit comprising:

a variable volume container for holding a quantity of ink; and

a valve actuator for closing the outlet valve as the refill unit engages the ink storage compartment.

2. A refill unit according to claim 1 wherein the variable volume container is a deformable ink bag.

3. A refill unit according to claim 2 wherein the ink storage compartment has an inlet valve and the refill unit further comprises an inlet valve actuator for opening valve as the refill unit engages the ink storage compartment.

4. A refill unit according to claim 3 wherein the inlet valve actuator and the outlet valve actuator are configured so that the outlet valve is closed before the inlet valve is opened as the refill unit engages the ink storage compartment.

5. A refill unit according to claim 4 wherein the inlet valve actuator and the outlet valve actuator are both spigot-like projections with a tri-star cross section for robust bending resistance in all lateral directions.

6. A refill unit according to claim 4 wherein the refill unit has a normally closed ink outlet, wherein during use, the ink outlet opens and forms a sealed connection with the inlet valve as the refill unit engages the ink storage compartment.

7. A refill unit according to claim 1 incorporated in a cartridge unit for an inkjet printer, the cartridge unit comprising:

the ink storage compartment and an ink feed system for connection to the printhead assembly with an array of ink ejection nozzles,

wherein the ink storage compartment has a variable storage volume and a displaceable wall section biased to expand the variable storage volume to generate a negative pressure therein, such that ink does not inadvertently leak from the ink ejection nozzles.

8. A refill unit according to claim 7 wherein:

the ink storage compartment has an interface for receiving the refill unit, the interface having an inlet valve biased to its closed configuration; and

the refill unit further comprises:

engagement formations for releasably engaging the interface; and

an inlet valve actuator for opening the inlet valve as the refill unit engages the ink interface so that the ink in the body is in fluid communication with the ink storage compartment.

9. A refill unit according to claim 1 for an ink cartridge having the ink storage compartment and an interface for receiving the refill unit, the interface having a normally closed inlet valve and a normally open outlet valve, both in fluid communication with the ink storage compartment,

wherein the refill unit further comprises a docking portion having an ink outlet and valve actuator formations, the actuator being one of the valve actuator formations, wherein during use, the docking portion releasably engages the interface to actuate the inlet and the outlet valves so the cartridge fills with ink from the body because of the negative pressure in the ink storage compartment.

10. A refill unit according to claim 1 , further comprising:

an ink outlet; and

a repressurizing arrangement,

wherein upon engagement of the refill unit with the ink storage compartment, the repressurizing arrangement causes part of the unit to be inwardly depressed as the ink from the body is drawn into the ink storage compartment through the ink outlet by the negative pressure until pressure equalization, and

upon subsequent disengagement of the refill unit from the ink storage compartment, the repressurizing arrangement releases the inwardly depressed part of the ink storage compartment to re-establish the negative pressure.

11. A refill unit according to claim 1 further comprising an ink outlet and a memory circuit for storing information relating to at least one characteristic of the ink wherein, during use, the memory circuit is interrogated by a controller for the printhead assembly to verify that the ink in the refill unit is suitable.

12. A refill unit according to claim 1 further comprising:

a docking portion for engaging the ink storage compartment, the docking portion having a base plate with an ink outlet for connection to an inlet port on the ink storage compartment; and

engagement formations for releasably engaging the ink storage compartment, the engagement formations being formed on the transverse centre line of the base plate, and wherein the centre of the ink outlet is spaced from the transverse centre line.

13. A refill unit according to claim 1 wherein:

the ink storage compartment is partially defined by a tubular flexible wall and has a constriction mechanism for constricting the flexible tubular wall by a predetermined amount, and

the ink refill unit further comprises a docking portion for engaging the ink storage compartment, the docking portion having an ink outlet for connection to an inlet port on the ink storage compartment, and a plurality of constriction actuators for actuating the constriction mechanism as the ink refill unit engages the ink storage compartment and releases the constriction mechanism as the ink refill unit disengages the interface.

14. A refill unit according to claim 1 for replenishing an ink cartridge in an inkjet printer, the ink cartridge having an interface for engaging the ink refill unit,

wherein the ink refill unit comprises:

an ink outlet for engaging a complementary ink inlet in the interface; and

a spigot extending from the body for insertion in an aperture in the interface, and

wherein the lateral cross section of the spigot is keyed to the shape defined by the aperture to ensure the ink refill is correctly matched to the cartridge.

15. A refill unit according to claim 1 further comprising a visual indicator to provide a visual indication when a predetermined quantity ink has flowed from the refill unit into the ink storage compartment.