Patent ID: 7607826

Claim:
A method for selecting a material for a thermal bend actuator of a printhead nozzle comprising an expensive element formed from the material, the method including the steps of: selecting the material from the group including silicides and carbides of titanium; borides, silicides, carbides and nitrides of tantalum, molybdenum, niobium, chromium, tungsten, vanadium, and zirconium; selecting the material on the basis that the material has at least one of the following properties; a resistivity between 0.1 μΩm to 10.0 μΩm; chemically inert in air; chemically inert in a chosen ink; and, depositable by CVD, sputtering or other thin film deposition technique; and selecting the material on the basis of ε, wherein εγ is a dimensionless constant for the material in accordance with the formula ɛ ⁢ ⁢ γ = E ⁢ ⁢ γ 2 ⁢ T ρ ⁢ ⁢ C wherein E is Young's module of the material; γ is the coefficient of thermal expansion; T is the maximum operating temperature, ρ is the density and C is the specific heat capacity.