US Patent 7686425 Printhead assembly with symmetrical tri-layer outer shell laminate

A printhead assembly for an inkjet printer includes an outer shell of a hot rolled tri-layer laminate of two different metals; a core element within the shell, the core element defining four separate ink reservoirs; a printhead constructed using MEMS techniques to provide ink nozzles, chambers and actuators; and a micro molding for distributing ink from the ink reservoirs to the printhead. The tri-layer shell is configured such that the effective coefficient of thermal expansion of the shell as a whole is substantially equal to that of silicon, and the outer layers of the tri-layer laminate are symmetrically disposed around a central layer thereof.