Pagewidth printhead assembly incorporating laminated support structure

1. A printhead assembly extending in pagewidth direction, the printhead assembly comprising:

an elongate support beam;

an elongate shell at least partially enclosing and restraining the support beam; and

a plurality of printhead integrated circuits mounted to the support beam and substantially aligned with one another in the pagewidth direction, wherein

the support beam has formed therein at least one printing fluid reservoir arranged in fluid communication with the plurality of printhead integrated circuits.

2. A printhead assembly as claimed in claim 1 , wherein the laminated structure has an effective coefficient of thermal expansion substantially equal to that of the plurality of printhead integrated circuits.

3. A pagewidth printhead assembly as claimed in claim 1 , wherein the shell is a laminated structure.

4. A printhead assembly as claimed in claim 3 , wherein the laminated structure has an odd number of laminates arranged so that the outer laminates have the same coefficient of thermal expansion as one another and a different coefficient of thermal expansion to that of the inner laminates.

5. A printhead assembly as claimed in claim 1 , wherein the coefficient of thermal expansion of each laminate is different to that of the printhead integrated circuits.

6. A printhead assembly as claimed in claim 1 , wherein the outer and inner laminates are formed of different metals.

7. A printhead assembly as claimed in claim 5 , wherein the outer laminates are formed of invar.

8. A printhead assembly as claimed in claim 1 , wherein the printhead integrated circuits are fabricated from silicon and constructed using micro-electromechanical techniques.