Why does paper only feed 3/4 way through on techko model sh3112pf?

I have a techko model sh3112pf shredder that had a paper jam. After removing the jam the shredder still cuts the paper into strips but stops pulling the paper in about 3/4 of the way through the paper. If I pull up on the paper it goes further in but not all the way. What is the cause of this odd behavior?