# US 2010/0134573 A1 · Printhead assembly with ink supply shut off

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- Number: US 2010/0134573 A1
- Document ID: US20100134573A1
- Status: Published application
- Kind: A1
- Application number: 12/697,266
- Filed: 2010-01-31
- Published: 2010-06-03
- Earliest claimed: 2006-03-03
- Assignees: Silverbrook Research Pty Ltd
- Inventors: Geoffrey Philip Dyer; Gregory Michael Tow; David William Jensen; Nicholas Kenneth Abraham; Kia Silverbrook
- Web page: https://patentgrep.com/patent/US20100134573A1

## CPC

- B41J 2/175: Ink supply systems {; Circuit parts therefor}
- B41J 2/14: Structure thereof {only for on-demand ink jet heads}
- B41J 2/155: for line printing
- B41J 2/1707: {Conditioning of the inside of ink supply circuits, e.g. flushing during start-up or shut-down}
- B41J 2/17596: {Ink pumps, ink valves}
- B41J 2002/14419: {Manifold}
- B41J 2002/14491: {Electrical connection}
- B41J 2202/19: Assembling head units
- B41J 2202/20: Modules
- B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS

## Abstract

A printhead assembly with a printhead and a shut off (138) valve that has a valve body (200) defining an ink inlet (202) for connection to an ink supply, an ink outlet (67) connected to the printhead IC. A diaphragm (212) is biased into sealing engagement with the valve seat (216) to provide a fluid seal between the ink inlet and the ink outlet. An actuator (204) unseals the diaphragm from the valve seat when energized. The valve protects the ink in the ink supply from contaminants that can migrate up the ink line during shut down periods. The diaphragm is biased to a closed position and so seals the ink supply from the printhead as a default condition even in the event of a power failure. The bias is strong enough to provide the fluid seal so that the seal is not compromised when the pressure difference between the inlet and the outlet is small.

## Claims

### Claim 1

A printhead assembly for an inkjet printer, the printhead assembly comprising:
a printhead with an array of nozzles for ejecting ink onto print media;
a shut off valve with an ink inlet for connection to an ink supply, an ink outlet for connection to the printhead, a valve seat and a diaphragm biased into sealing engagement with the valve seat to seal the printhead from the ink supply; and,
an actuator for unsealing the diaphragm from the valve seat when energized; wherein,
the ink outlet and the ink inlet are both in fluid communication with one side of the diaphragm, such that unsealing the diaphragm draws the diaphragm away from the valve seat to lower the fluid pressure in the ink inlet and the ink outlet.

### Claim 2 (depends on 1)

A printhead assembly according to claim 1 wherein the printhead has a printhead IC in which the array of nozzle is formed.

### Claim 3 (depends on 1)

A printhead assembly according to claim 1 wherein the bias urging the diaphragm into sealing engagement with the valve seat is residual tension in the diaphragm.

### Claim 4 (depends on 1)

A printhead assembly according to claim 1 wherein the actuator works against the bias of the diaphragm to unseal the valve seat.

### Claim 5 (depends on 1)

A printhead assembly according to claim 1 wherein the actuator has a solenoid.

### Claim 6 (depends on 1)

A printhead assembly according to claim 1 wherein the actuator has a shape memory alloy.

### Claim 7 (depends on 6)

A printhead assembly according to claim 6 wherein the shape memory alloy comprises a Nitinol™ wire.

### Claim 8 (depends on 1)

A printhead assembly according to claim 1 wherein the diaphragm is polyurethane.

### Claim 9 (depends on 1)

A printhead assembly according to claim 1 wherein the actuator draws the diaphragm away from the valve seat more quickly than the diaphragm reseals the valve member to the valve seat.

### Claim 10 (depends on 1)

A printhead assembly according to claim 1 wherein the valve seat has a frusto-conical surface for sealing against a complementary surface extending from one side of the diaphragm.