US Patent 9314970 Fluid-dispensing head for a 3D printer

A head assembly for an extrusion-based 3D printer includes: a fluid-dispensing head having a manifold and at least two fluid-dispensing nozzles, of different sizes, which are mounted in communication with a melt chamber in a manifold. Outlets of each nozzle are closed by respective valve members. A rocker serves both to pivot the nozzles to their lowermost nozzle-operating position and to actuate the valve members, for ready switching between the valves, such that the smaller nozzle can be used for high resolution work, and the larger nozzle can be used for bulk infill.