Cylinder member and image forming apparatus

A cylinder member comprising:

• a cylinder body having a substantially circular cross section and including a dent portion that extends in an axial direction;
• a sheet member wrapped around the cylinder body and including a metal layer that is in contact with the cylinder body and an outer layer provided on the metal layer;
• a first attachment member provided on a first end portion of the sheet member and removably attached to the dent portion at a first side of the dent portion in a circumferential direction;
• a second attachment member provided on an end portion of the metal layer that protrudes from the outer layer in the circumferential direction at a second end portion of the sheet member, the second attachment member being removably attached to the dent portion at a second side of the dent portion in the circumferential direction;
• a tension-applying mechanism that pulls the second attachment member in a depth direction of the dent portion to apply tension to the metal layer;
• a projection provided on one of the second attachment member and the end portion of the metal layer;
• and
• a fitting portion provided on other one of the second attachment member and the end portion of the metal layer and fitted to the projection.