the inner layer 26 can be any suitable insulating material such as glass amorphous silicon dioxide or even air it will be appreciated that the thermal bend actuator 22 will find application in any micro electro mechanical system in which a prime mover is required thus at least one of the outer layers 24 is connectable to drive circuitry of such a micro electro mechanical device in fig3 reference numeral 30 generally indicates a fluid ejection device in accordance with the invention in this embodiment the fluid ejection device is in the form of a nozzle arrangement of an ink jet printhead which includes the actuating mechanism 20 it is to be appreciated that reference to the nozzle arrangement 30 is for illustrative purposes and should not be construed as limiting the invention to this particular embodiment the nozzle arrangement 30 is formed on a wafer substrate 32 in a successive deposition and etching process which forms part of an integrated circuit fabrication technique conventionally used in the manufacture of micro electro mechanical systems in this particular example the nozzle arrangement 30 is formed on a drive circuitry layer 34 which itself is formed on the wafer substrate 32 a support post 36 extends from the drive circuitry layer 34 the thermal bend actuator 22 is mounted cantilever fashion on the support post 36 one of the outer layers 24 is in electrical contact with the drive circuitry layer 34 so that movement of the bend actuator 22 can be achieved with a control system not shown connected to the drive circuitry layer 34 a cylindrical wall 38 is formed on the drive circuitry layer 34 to define a.