Patent ID: 7140720

Claim:
A micro-electromechanical fluid ejection device that comprises a substrate that defines a plurality of fluid supply channels and a plurality of chambers in fluid communication with respective fluid supply channels; a drive circuitry layer that is positioned on the substrate; a plurality of roof structures that are connected to the drive circuitry layer to cover respective fluid chambers, each roof structure defining a fluid ejection port; and at least one actuator that is positioned in each roof structure, each actuator being electrically connected to the drive circuitry layer to be displaceable into and out of its respective chamber to eject a drop of fluid from the fluid ejection port, wherein at least some of the roof structures comprise a fixed portion in contact with the fluid that remains stationary during fluid ejection, each fixed portion comprising a rim that defines the fluid ejection port and support arms that extend from the drive circuitry layer to support the rim above the respective fluid inlet channel, the actuator arms being interposed between consecutive support arms.