One of the stepped portions is to be engaged with the gear, and the other one of the stepped portions is to be pivotably fastened to the support frame (not shown) of the printer to support the shaft 1??? with respect to the support frame. [0031] After that, as shown in FIG. 2, the smaller rollers 2??? are made of plastic, such as the ABS and PC, and are directly formed on an outer surface of the s