Shaft and image forming apparatus

A shaft on which a torque limiter, applying a constant rotational load to a rotatable member attached to the torque limiter during rotation of the rotatable member, is mounted, the shaft comprising:

• a rotation restricting portion inserted into and engaged with counterpart engaging portions of the torque limiter to restrict rotation of the torque limiter,
• wherein the rotation restricting portion is provided with an outer circumferential portion which is projected in an outer diameter direction from an outer circumference of the shaft and of which an outer circumferential surface is formed parallel with an outer circumferential surface of the shaft, and at least a pair of engaging portions connected to the outer circumferential portion and engaging with the counterpart engaging portions of the torque limiter,
• wherein the pair of the engaging portions are provided in positions opposite to each other with respect to a center of the shaft,
• wherein a tip portion of each of the pair of the engaging portions has a semicircular cylindrical shape of which diameter is widthwise,
• wherein a height of the outer circumferential surface of the outer circumferential portion from the outer circumferential surface of the shaft is the same height of the pair of engaging portions of the rotation restricting portion from the outer circumferential surface of the shaft,
• wherein each engaging portion of the pair of engaging portions of the rotation restricting portion is provided with the tip portion having a R shape opposing one of the counterpart engaging portions of the torque limiter, and a width thereof in a direction perpendicular to an inserting direction into the one of the counterpart engaging portions of the torque limiter is a width capable of being inserted into the one of the counterpart engaging portions of the torque limiter, and
• wherein the outer circumferential portion of the rotation restricting portion is divided into separated outer portions that are connected to the pair of engaging portions of the rotation restricting portion and are not connected to each other.