Sorry if this is a newbie question but I've had a 4900 for about a year now and this is the first time I've run into this problem. Been working on a print for a local artist and, after a number of proofs, etc., I'm finally ready to do a run of his prints. We settled on Moab Entrada Rag Natural 300 and I've had no problem running this paper through the printer .. until now. Suddenly, after more than a few successful 17x22 sheets having been run through in the proofing process, the printer is now crumpling the trailing corners of each sheet I try to put through. I noticed that it appears to running the print head back and forth even after it's well past the point of printing any image .. I don't think it was doing that before when it was printing w/o the crumpled corners. I haven't changed any printer settings .. it just seems to have started doing this on it's own. I need to get this run started but I can't if it's going to crumple the corners of each sheet. Any suggestions?