Patent ID: 8616544

Claim:
A document feeder for feeding document sheets one at a time from a stack on a tray by pressing one or more pick-up rollers against an uppermost document sheet and guiding one edge of the document sheet, the one edge being one of two edges in a width direction perpendicular to a document transport direction, the document feeder comprising: a document size obtainer that obtains size information indicating a width of the document sheet; and a center-of-contact shifting mechanism that shifts a center of contact of each pick-up roller along an axial direction of the pick-up roller according to the obtained size information, the center of contact being a central point of an area where the pick-up roller is in contact with the document sheet, wherein each pick-up roller is in a barrel shape, and the center-of-contact shifting mechanism shifts the center of contact of each pick-up roller by axially tilting the pick-up roller relative to a surface of the document sheet.