Ink refill unit with sequential valve actuators

1. A refill unit for refilling an ink storage compartment with an interface for releasably engaging with the refill unit, the interface having valves for controlling ink flows into, and out of, the storage compartment, the refill unit comprising:

a body containing a quantity of ink;

an ink outlet; and,

valve actuators for actuating the valves when the refill unit engages the interface, the valve actuators being spigot-like projections with a tri-star cross section for robust bending resistance in all lateral directions; such that,

the valve actuators actuate the valves in a predetermined sequence.

2. A refill unit according to claim 1 wherein the interface has a normally closed inlet valve for connection to the outlet of the refill, and a normally open ink outlet valve for connection to an inkjet printhead, wherein during use the valve actuators close the outlet valve before opening the inlet valve.

3. A refill unit according to claim 2 wherein during use, the ink storage compartment maintains the ink at a negative pressure and the valve actuators do not actuate the inlet valve until the outlet of the refill has a sealed connection with the inlet valve.

4. A refill unit according to claim 3 wherein the valve actuators comprise an inlet valve actuator and an outlet valve actuator.

5. A refill unit according to claim 4 wherein the tri-star cross sections are configured to key into correspondingly shaped apertures in the interface to ensure the refill is matched to the correct ink storage compartment.

6. 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.

7. A refill unit according to claim 1 , wherein:

the ink storage compartment supplies ink to a printhead assembly;

the interface has 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.

8. A refill unit according to claim 1 , wherein:

the interface has a normally closed inlet valve and a normally open outlet valve, both in fluid communication with the ink storage compartment; and

the refill unit further comprises a docking portion having an ink outlet and valve actuator formations, which, during use, 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.

9. A refill unit according to claim 1 , wherein:

the ink storage compartment supplies ink to a printhead assembly;

the refill unit interfaces with the ink storage compartment via a normally open outlet valve; and

the refill unit further comprises an outlet valve actuator for closing the outlet valve as the refill unit engages the ink storage compartment.

10. A refill unit according to claim 1 , wherein:

the ink storage compartment supplies a printhead assembly with an array of nozzles, wherein during use, the ink storage compartment is maintained at a negative pressure to avoid inadvertent ink leakage from the nozzles;

the refill unit further comprises a repressurizing arrangement;

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 incorporated in a cartridge for an inkjet printer, the cartridge comprising:

the ink storage compartment having opposed wall sections connected by a flexible wall arrangement to define a variable ink storage volume; and

an ink feed system for supplying for supplying ink to a printhead with an array of nozzles,

wherein one of the opposed wall sections is displaceable and biased to expand the variable ink storage volume to create a negative pressure in the ink storage compartment for avoiding inadvertent ink leakage from the nozzles.

12. A refill unit according to claim 1 for refilling an ink cartridge that forms part of an inkjet printer, the printer also having a printhead, control circuitry and an interface for releasably engaging the refill unit,

wherein the refill unit further comprises an ink outlet and a memory circuit for storing information relating to at least one characteristic of the ink, and

wherein, during use, the memory circuit allows to the control circuit to interrogate it to verify that the ink in the refill unit is suitable for the printer.

13. A refill unit according to claim 1 incorporated in a printhead maintenance assembly for an inkjet printhead, the printhead having a nozzle plate with an array of nozzles formed therein, the printhead maintenance assembly comprising:

a capper to cover the array of nozzles when the printhead is not in use; and,

a cleaner for engaging the nozzle plate and wiping across the nozzles,

wherein the cleaner is positioned between opposing sides of the capper.

14. A refill unit according to claim 1 , wherein the printhead assembly is incorporated in an inkjet printer comprising:

a maintenance assembly for moving between a capped position where the assembly covers the array of nozzles, and an uncapped position spaced from the array of nozzles; and

a motorized drive for moving the maintenance assembly between the capped position and the uncapped position.

15. A refill unit according to claim 1 for replenishing an ink cartridge in an inkjet printer, wherein the refill unit further comprises:

an ink storage compartment;

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

engagement formations for releasably engaging the interface, 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.

16. A refill unit according to claim 1 for replenishing an ink cartridge in an inkjet printer, 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 interface of the cartridge, the docking portion having an ink outlet for connection to an inlet port on the interface, and a plurality of constriction actuators for actuating the constriction mechanism as the ink refill unit engages the interface and releases the constriction mechanism as the ink refill unit disengages the interface.

17. 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:

the 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.

18. A refill unit according to claim 1 for replenishing an ink cartridge in an inkjet printer, wherein the ink refill unit comprises:

the ink outlet for engaging a complementary ink inlet in the cartridge; and

a visual indicator to provide a visual indication when a predetermined quantity ink has flowed from the refill unit into the cartridge.

19. A refill unit according to claim 1 incorporated in an inkjet printer comprising:

an outer casing with a hingedly mounted panel for access its interior; and

a cradle housed within the outer casing for supporting an ink cartridge, the cradle having a hingedly mounted lid that opens to allow the ink cartridge to be inserted and removed,

wherein the hinge axis of the lid and the hinge axis of the panel are parallel, and

the lid and the panel both open in the same direction.

20. A refill unit according to claim 1 incorporated in an inkjet printer comprising:

a replaceable pagewidth printhead with an array of nozzles and printhead contacts for transmitting power and print data to the nozzles;

corresponding contacts for supplying the power and print data to the printhead contacts; and

a selective biasing mechanism, such that the printhead contacts and the corresponding contacts are biased into engagement during printing and released from biased engagement when installing or removing the printhead.