US Patent 7920936 Volume element printing system for simultaneously printing multiple layers

A three dimensional object creation system for printing a three dimensional object comprised of layers stacked vertically with respect to each other includes a series of printheads for printing the layers, the series of printheads simultaneously printing at least two layers of different vertical positions within the stack; and a semiconductor memory for storing data defining at least one layer. The series of printheads are arranged in groups of one or more printheads per group, each group being fixedly positioned downstream of a preceding group with respect to the three dimensional object. Each group of printheads is adapted to print a layer at a predetermined vertical position within the stack.