My 4 year old HP Printer 2710 problems picking up?

My 4 year old HP Printer 2710 all in one has occasional problems picking up paper and displays an out of paper sign when there is plenty there. It is worst immediately after reloading. I occasionally riffle the paper stack before loading but it doesnt usually fix it. I have to push the top sheet against the feeder to make it work which is aproblem if i have a big document to print. HELP!