Patent ID: 7731181

Claim:
A paper feeding apparatus, comprising: a paper tray having a front surface for supporting paper and a rear surface; a paper guide, disposed on the paper tray and being movable, for abutting against an edge of the paper; a roller set disposed on the rear surface and being rotatable, wherein the roller set comprises a wheel, a plurality of rollers, and a plurality of to-be-sensed components of different sizes are attached to a circumference of the wheel; a belt connected to the paper guide and wound around the roller set, wherein the belt and the paper guide move synchronously to rotate the wheel and the rollers, and the to-be-sensed components move with wheel synchronously; a sensing mechanism, disposed on the rear surface of the paper tray, for sensing the to-be-sensed components and thus outputting a sensing signal; and a control unit for receiving the sensing signal and determining size of the paper according to the sensing signal; when the paper guide moves toward the edge of the paper, the paper guide drives the belt to rotate the rollers and the wheel; and when the paper guide abuts against the edge of the paper, the sensing mechanism senses the to-be-sensed components and thus outputs the sensing signal to the control unit.