Printhead supporting shell
View Patent ↗A printhead supporting shell ( 4 ) is provided for a pagewidth printhead assembly ( 1 ). The shell comprises a longitudinal laminated structure defining an interior space and formed from continuous layers of at least two materials ( 10,11 ). The layers are odd in number and disposed symmetrically about a central layer ( 10 ). In preferred embodiments, the supporting shell is adapted to a pagewidth printhead ( 12 ).
1. A printhead supporting shell device for a pagewidth printhead assembly, the shell comprising:
a longitudinal laminated structure defining an interior space, formed from continuous layers of at least two materials;
the layers being odd in number and disposed symmetrically about a central layer.
2. A device according to claim 1 , wherein:
two layers which are symmetrically disposed about the central layer are made from the same material and have the same thickness.
3. A device according to claim 1 , wherein:
the shell further comprises a longitudinal gap adapted to receive a component of a printhead.
4. A device according to claim 1 , wherein:
the laminated shell is formed from at least three metals laminated together, the laminate having inner and outer layers which have the same coefficient of thermal expansion.
5. A device according to claim 1 , wherein:
the shell has outer layers which are made from invar.
6. A device according to claim 1 , wherein:
each material has a different coefficient of thermal expansion.
7. A device according to claim 6 , wherein:
at least two materials have coefficients of expansion which are different than the coefficient of expansion of silicon, one material having a coefficient of expansion which is greater than the coefficient of expansion of silicon and one material having a coefficient of expansion which is less than the coefficient of expansion of silicon.
8. A device according to claim 1 , wherein:
two layers which are symmetrically disposed about the central layer have different thicknesses, the lateral cross section of the shell, in compensation, being configured to prevent bowing.
9. A device according to claim 1 , wherein:
all of the layers are metal.
10. A device according to claim 1 , further comprising:
an extruded plastic core in which is formed one or more ink reservoirs.
11. A device according to claim 10 , wherein:
the reservoirs lead to a printhead which protrudes from the shell.
12. A device according to claim 11 , wherein:
the printhead is a modular printhead comprising a plurality of modules disposed along the length of the core.
13. A device according to claim 12 , wherein:
each module is fabricated from silicon.
14. A device according to claim 13 , wherein:
each module further comprises ink nozzles, chambers and actuators.