Epson ET-4750 Paper Feed Problem

My Epson ET4750 printer sometimes will feed the paper sheet up to print then other times it won't (about 50 / 50). When it doesn't feed it usually says it's out of paper but it's not. I've tried 24lb, 22lb & 20lb paper. No difference. I checked the feed roller and it is clean and looks good. How do I fix this? It worked fine until 4 or 5 months ago. YOUR HELP PLEASE!

T.C.M.