Printing 7x9 paper in LW 16/600 PS?

I am printing over 1000 sheets of 7x9 paper in the LW 16/600 PS with the paper scooted to the left edge of the paper tray and stopped at the bottom and right edge to run smoothly. It only prints one copy and then the paper jam light comes on. Pull out the paper tray, push in and it will print another one (that's right, just 1) before the light comes on again. Can I not run 50 at a time instead of 1?

HELP.