US Patent 7306323 3D object creation system comprising a plurality of layer groups

A three-dimensional object creation system is provided. The system comprises a plurality of stationary printhead layer groups, each layer group comprising at least one printhead for printing a respective layer of the object; and a conveyor for conveying a partially-formed object past the layer groups. The printheads are configured to print simultaneously such that a plurality of different layers are printed simultaneously by the layer groups.