Printhead assembly with ink chamber defining structures

1. A printhead assembly for an ink jet printer, the printhead assembly comprising

an elongate ink supply structure that defines at least one longitudinally extending ink passage and at least one set of holes in fluid communication with the at least one ink passage;

a first ink chamber defining structure that defines at least one ink chamber formation on one side and at least one set of ink inlet openings on an opposite side in fluid communication with the at least one ink chamber formation, the first ink chamber structure being engageable with the ink supply structure so that each ink inlet opening is in fluid communication with a respective hole of the ink supply structure;

a second ink chamber defining structure that defines at least one ink chamber formation on one side and at least one set of exit holes on an opposite side in fluid communication with the at least one ink chamber formation, the first and second ink chamber structures being engaged with each other so that respective ink chamber formations define at least one ink chamber; and

at least one elongate printhead chip, having a plurality of ink inlets, that is mounted on the second ink chamber defining structure so that each ink inlet is in fluid communication with a respective exit hole of the second ink chamber structure.

2. A printhead assembly as claimed in claim 1 , which includes a film layer that is interposed between the first and second ink chamber defining structures, the film layer defining a number of openings for the passage of ink through the film layer.

3. A printhead assembly as claimed in claim 2 , in which the film layer is of a substantially inert polymer.

4. A printhead assembly as claimed in claim 1 , in which the first and second ink chamber defining structures are micro-moldings.

5. A printhead assembly as claimed in claim 1 , in which the second ink chamber defining structure is a liquid crystal polymer blend.

6. A printhead assembly as claimed in claim 1 , in which the elongate ink supply structure defines a number of passages, each passage corresponding with a respective ink, and a number of sets of holes, each set in fluid communication with a respective passage, the first ink chamber defining structure defining a number of ink chamber formations and a number of corresponding sets of ink inlet openings, each set corresponding with a respective set of holes and the second ink chamber defining structure defining a number of ink chamber formations and a number of corresponding sets of exit holes, each set corresponding with a respective set of ink inlets of the at least one printhead chip.

7. A printhead assembly as claimed in claim 1 , which includes an elongate channel member that defines a channel, the ink supply structure and the ink chamber defining structures being positioned in the channel, such that the channel imparts structural rigidity to the printhead assembly.

8. A printhead assembly as claimed in claim 7 , in which the channel member is of a nickel iron alloy.