You just gave up on the fastest way to innovate. Big mistake. You can not "remain 100% committed to our open source ethos." and file patents. Follow the money - all of the money you just wasted on lawyers filing patents could have gone to engineers to develop better printers. You could have obtained priority on the invention by simply posting it on a public blog or the peer reviewed literature. This is just sad. We know exactly what happens to companies that do this - take a close look at how things are going for Makerbot.