Printhead assembly with thermal equalization characteristics
View Patent ↗A printhead assembly includes a support member of a composite material that defines at least one ink reservoir. A printhead integrated circuit is mounted on the support member. A substrate material of the printhead integrated circuit and the composite material both have substantially the same coefficient of thermal expansion.
1. A printhead assembly which comprises
a support member of a composite material that defines at least one ink reservoir; and
a printhead integrated circuit mounted on the support member, wherein
a substrate material of the printhead integrated circuit and the composite material both have substantially the same coefficient of thermal expansion.
2. A printhead assembly as claimed in claim 1 , in which the substrate material of the printhead integrated circuit is silicon.
3. A printhead assembly as claimed in claim 2 , in which the support member has a core reservoir structure that defines a number of ink reservoirs for respective inks and an outer shell.
4. A printhead assembly as claimed in claim 3 , in which the outer shell is laminated and comprises at least two layers of different materials selected such that a combined coefficient of thermal expansion of a lamination of such metals is substantially the same as that of silicon.
5. A printhead assembly as claimed in claim 4 , in which the outer shell comprises three layers of two different metals, with an inner layer of one metal and outer layers of another metal.
6. A printhead assembly as claimed in claim 5 , in which the outer shell is a hot rolled laminate.
7. A printhead assembly as claimed in claim 5 , in which the outer layers are invar and the inner layer has a coefficient of thermal expansion which is greater than that of invar.
8. A printhead assembly as claimed in claim 3 , in which the core reservoir structure has a portion which extends from the shell, the printhead integrated circuit being mounted on the portion.