Multi-path valve for printhead

1. A printer comprising:

(i) a printhead connected to an ink source via a closed ink flow loop;

(ii) a multi-path valve, comprising:

a body;

a first port on the body connected to the ink source;

a second port on the body connected to the printhead;

a third port on the body for connected to a bypass ink path which bypasses the printhead on said closed loop;

a fourth port on the body for connected to a gas vent on said closed loop;

a chamber within the body via which the first, second, third and fourth ports are able to be interconnected;

a selection device for selectively establishing interconnection between the first, second, third and fourth ports to allow ink flow therebetween; and

(iii) a controller for controlling the selection device such that the first port, the second port and the third port are all open during a normal printing operation.

2. A printer according to claim 1 , wherein:

said closed loop comprises a first path between the ink source and one longitudinal end of the media width of the printhead and a second path between the ink source and the other longitudinal end of the media width of the printhead; the bypass path bridges across the printhead between the first and second paths; and

the valve is configured to be located on the first path.

3. A printer according to claim 1 , wherein said closed loop and bypass path comprise fluid hoses, the first, second, third and fourth ports being configured to connect with the fluid hoses.

4. A printer according to claim 1 , wherein the selection device comprises a driven shaft and selection members on the shaft, the selection members being rotated by driven rotation of the shaft so as to selectively establishing the interconnections between the first, second, third and fourth ports.

5. A printer according to claim 4 , wherein the selection members define seals for respective ones of the first, second, third and fourth ports.