Piston-driven fluid-ejection apparatus

A surface-micromachined fluid-ejection apparatus, comprising:

• (a) a substrate;
• (b) an open-ended fluid-ejection chamber formed on the substrate from a plurality of stacked and patterned layers of polycrystalline silicon, with the fluid-ejection chamber being adapted to receive a fluid, and with the fluid-ejection chamber further having a fluid-ejection orifice formed through a wall thereof;
• (c) a fluid reservoir formed on the substrate from the plurality of stacked and patterned layers of polycrystalline silicon and connected to the fluid-ejection chamber to supply the fluid thereto;
• (d) a piston formed on the substrate and moveable in the plane of the substrate to eject a jet or drop of the fluid through the fluid-ejection orifice;
• and
• (e) at least one microelectromechanical actuator formed on the substrate and operatively connected to provide reciprocating motion to the piston, with the microelectromechanical actuator being located outside the fluid reservoir and outside the fluid-ejection chamber.

A surface-micromachined fluid-ejection apparatus, comprising:

• (a) a substrate;
• (b) an open-ended fluid-ejection chamber formed on the substrate, with the fluid-ejection chamber forming an electric-field-free region whereby a fluid disposed therein is not contacted by any electric field produced by the apparatus, and with the fluid-ejection chamber further having a micron-sized fluid-ejection orifice formed through a top wall thereof;
• (c) a fluid reservoir formed on the substrate and connected to the fluid-ejection chamber to supply the fluid thereto;
• (d) a piston formed on the substrate and moveable in the plane of the substrate to eject a portion of the fluid through the fluid-ejection orifice;
• and
• (e) at least one microelectromechanical actuator formed on the substrate outside the fluid reservoir and operatively connected to provide reciprocating motion to the piston.