The HP Photosmart C4280 is an all-in-one printer that features a scanner. If your display screen shows "Paper Jam," the current print job may not be able to finish. There are two possible places for a paper jam: the rear paper-feed roller or the front paper-feed roller. HP recommends checking the rear paper-feed roller first, as it's the likely place for a paper jam. If no jam exists, you should then check the front.