Image forming apparatus, drum unit, image forming module, and method of insertion and removal of a damper into and from an image carrier drum

A latent image carrier includes a thin-walled cylinder with a chargeable photosensitive layer. The latent image carrier is configured to form an electrostatic latent image corresponding to an optically written image. A cylindrical damper including an elastic body disposed inside the latent image carrier. A first end of the cylindrical damper includes a wall extending inward toward an axis of the damper. A second end of the damper, opposite the first end along the axis of the damper, includes an opening, which is open in an axial direction. The wall includes a through-hole connecting an internal cavity and an outside of the damper. An outer diameter of an outermost part of the first end of the damper along the axis of the damper is smaller than an outer diameter of an outermost part of the second end of the damper along the axis of the damper.