Apparatus is disclosed for printing three-dimensional objects, particularly objects having a substantially spherical shape. A pad is provided for printing by means of pad printing. The pad has a silicon shape with a determined thickness, and is mounted on a hollow pad holder made of an undeformable material...http://www.google.com.au/patents/US6604458?utm_source=gb-gplus-sharePatent US6604458 - Pressurized pad for printing three-dimensional spherical or curved objects
