US Patent 10076869 Electrostatic 3-D printer using leveling material and mechanical planer

A three-dimensional (3-D) printer includes build and support material development stations positioned to transfer layers of build and support materials to an intermediate transfer surface. A platen having a flat surface is positioned to contact the intermediate transfer surface. The intermediate transfer surface transfers a layer of the build and support materials to the flat surface of the platen as the platen contacts one of the layers on the intermediate transfer surface. A dispenser is positioned to deposit a leveling material on the layer on the platen, and a mechanical planer is positioned to contact and level the leveling material on the layer on the platen to make the top of the leveling material parallel to the flat surface of the platen.