While we've been mulling over the latest developments in high end digital printing the boffins at Evil Mad Science Laboratories have made a dinky open source art robot that can print on round or egg-shaped objects.
The Eggbot has an adjustable chassis that allows you to mount spherical or egg-shaped objects, and rotate them using a motor under computer control. A second motor moves a pen about an axis perpendicular to that “egg” axis, and a small servo motor raises or lowers the pen above the egg surface.
The first batch of kits has sold out but if you place an order now there might just be enough time to get one shipped from the US and print some branded baubles before the christmas rush.