| Abstract: | A piston structure is movably mounted within a fluid chamber. Movement of the piston structure towards a faceplate causes a portion of the fluid between the piston and the faceplate to be forced out of the nozzle hole in the faceplate, forming a drop or jet of the fluid. Viscous forces that are generated by the flow of fluid along a working surface of the piston structure toward and away from the nozzle hole generate a force that resists the movement of the piston structure. This resistance force tends to slow the piston motion, and prevents the piston from contacting the faceplate. In various embodiments, the fluid chamber is defined by a cylinder structure. The piston structure moves within the cylinder structure. The cylinder structure and the faceplate define the fluid chamber. The cylinder structure and the piston structure are designed to cooperate so that the movement of the piston structure within the cylinder structure ejects fluid according to various design criteria. In various embodiments, a free space is provided between the faceplate and the piston structure at its maximum displacement towards the faceplate. |