Self-cleaning inkjet printhead assembly

1. An inkjet printhead assembly which comprises

a carrier;

an ink supply assembly that is mounted on the carrier and defines a plurality of printhead chip receiving formations that are each dimensioned to engage a printhead chip and a plurality of ink supply conduits that terminate at the formations to supply ink to printhead chips engaged with the formations; and

a plurality of inkjet printhead chips that are engaged with respective said formations to receive the ink via passages defined by the printhead chips in fluid communication with respective ink supply conduits, the ink supply assembly further defining a gas flow path that terminates at each formation, the ink supply assembly being connectable to a pressurized gas supply so that gas can be directed over each printhead chip to inhibit the build-up of dust and debris on the printhead chips.

2. An inkjet printhead assembly as claimed in claim 1 , in which the ink supply assembly includes an ink conduit structure, the ink conduit structure defining a plurality of converging ink conduits that are in fluid communication with respective passages of the printhead chips and an ink distribution structure that is connected to the ink conduit structure, the ink distribution structure defining a plurality of ink ducts, each ink duct being in fluid communication with a respective set of ink conduits.

3. An inkjet printhead assembly as claimed in claim 2 , in which the ink distribution structure defines a gas duct and the ink conduit structure defines a number of gas conduits in fluid communication with the gas duct, such that the gas duct and the gas conduits define the gas flow path.

4. An inkjet printhead assembly as claimed in claim 3 , in which a valve closure is positioned in the gas duct, the valve closure defining a valve chamber in fluid communication with the supply of gas and an opening between the valve chamber and the gas duct, the valve closure being displaceable relative to the gas duct between an open position in which gas is permitted to enter the gas duct and a closed position in which gas is inhibited from entering the gas duct.

5. An inkjet printhead assembly as claimed in claim 4 , which includes a platen assembly that is mounted on the carrier and is displaceable between an operative position to support a print medium as the printhead chips carry out a printing operation on the print medium and an inoperative position, the platen assembly being connected to the valve closure to displace the valve closure into its open position when the platen assembly is displaced into its operative position.

6. An inkjet printhead assembly as claimed in claim 3 , in which the ink conduit structure is in the form of a stack of sheets, each sheet having a plurality of openings and inwardly directed channels defined therein, the openings and channels being dimensioned and positioned so that, when the sheets are in the stack, the openings and channels together define the converging ink conduits, the sheets defining gas holes and gas passages that are positioned and dimensioned to define the gas conduits.

7. An inkjet printhead assembly as claimed in claim 6 , in which each sheet is in the form of a micro-molded structure.