Conveying belt mechanism for an automatic feeder

摘要

A conveying belt mechanism for an automatic document feeder, for conveying a document placed on a document bearing plate to a document exposure position on a transparent platen. The conveying belt mechanism includes a driving roller and a driven roller disposed above the transparent platen, with a predetermined spacing provided between the two rollers in a document feeding direction, an endless conveying belt looped over the driving roller and the driven roller, pressing rollers disposed between the driving roller and the driven roller for pressing the endless conveying belt against the transparent platen, and belt guides mounted at both ends of the driven roller. Each belt guide includes a boss portion mounted on a rotating shaft of the driven roller so as to be capable of relative rotation, a detachment-preventing portion which protrudes from the boss portion diametrically beyond an outer peripheral surface of the driven roller and which has a front end bent inwardly, and a rotation stopping portion provided in the boss portion, the rotation stopping portion being engaged with a rotation restraining member.