[steveklabnik]

There's a bunch. http://www.google.com/patents?q=fused%20deposition%20modelin...

They cover many different parts of the process, support materials, anything you can think of.

[bioweek]

So they expire soon? Could we use the patents as specs to build an open source one when they come of age?

Wait a minute, isn't this what cupcake CNC uses? Why haven't reprap been sued?

[steveklabnik]

Yep, they could probably be sued under this. Here's the reason why they haven't: they're targeting totally different markets. "Real" engineers would never use a Cupcake CNC to make test parts, as the resolution is so low. So they're not really a threat to their business.