this sounds like a recalibration cycle, which can be triggered by a few things (but not sure what they are ). Symptom is the print head moves back and forth the entire width of the printer, but nothing prints. If you power the machine down during this process it will have to start from the beginning. It's unfortunate the display doesn't really clue you in on what is going on, but to resolve it you must let it finish (which can actually take some time).
I learned this the hard way, and the answer for me was found here on the forum, here is my thread on the problem. http://www.luminous-landscape.com/forum/index.php?topic=64223.0