Paper feeder and image forming apparatus

A paper feeder, comprising:

• an acquiring device for acquiring thickness information on a sheet of paper;
• a driving roller for rotating by being supplied with torque;
• a plurality of driven rollers for rotating with the driving roller when in compressive contact with the driving roller;
• a driven roller supporter for supporting the driven rollers such that each of the driven rollers can rotate under a different rotational load;
• a driver for changing the position of the driven roller supporter relative to the driving roller;
• and
• a controller for selecting one of the driven rollers on the basis of the acquired thickness information and activating the driver to bring the selected roller into compressive contact with the driving roller,
• wherein the acquiring device includes feed rollers supported near an end of a feed unit holding sheets of paper, the end being downstream in the feeding direction in which the paper feeder feeds the sheet, and wherein the acquiring device acquires the thickness information on the basis of the force acting on the feed rollers.