Patent ID: 6944419

Claim:
An electrophotographic image forming apparatus, comprising: a fixing device having a heat roller and a press roller which abuts against and presses said heat roller, and at least one cleaning device having a backup roller which abuts against and presses said heat roller in order to remove remaining toner attaching to a surface of the heat roller, wherein said backup roller has a two-layer structure of a metal shaft core and a resilient layer, as an outer layer for said shaft core, made of a resilient body, a diameter of said backup roller gradually decreasing from a projecting axial center toward two axial ends, so that an entire outer shape of the backup roller forms a crown or spindle shape, wherein the cleaning device comprises a cleaning web converted between the backup roller and the heat roller to come into slidable contact therewith, a feed device for supplying the cleaning web, and a take-up device for recovering the cleaning web, and wherein said shaft core of said backup roller is a circular cylindrical shaft with a diameter of 5 mm to 15 mm which is made of iron, SUS (stainless steel), or aluminum, and said resilient layer of said backup roller is made of a resilient body containing silicone foamed rubber and having a surface roughness Ra of 20 μm to 80 μm, a hardness of 10 to 40 degrees (Asker C hardness), and a thickness of 3 mm to 20 mm, such that a thickness of said resilient layer around said shaft core is uniform in a direction of diameter, and is large at the axial center and gradually decreases toward the two axial ends in an axial direction, so a difference t in thickness between the axial center and the two axial ends is 0.05 mm to 1 mm.