To constitute a damping material capable of efficiently controlling not only electrification noise occurring when an image is formed by applying a DC voltage with an AC voltage superposed on an electrifying member, but also, rubbing noise of a cleaning blade so as not to give an unpleasant feeling while giving consideration to the attachment, the interchangeability and the environment (resources saving and energy saving) etc., to provide an electrophotographic photoreceptor incorporating the damping material and the manufacturing method of the electrophotographic photoreceptor, and to provide an image forming apparatus and a process cartridge equipped with the electrophotographic photoreceptor.

The image is formed by introducing indirect electrophotography, wherein the DC voltage with the AC voltage superposed is applied on the electrophotographic photoreceptor by a contact electrifier or a non-contact electrifier, thereafter, an electrostatic latent image is formed by optical-writing, next, the image is developed by reverse-developing by a developing device. Besides, the electrophotographic photoreceptor incorporates the damping material constituted of a bag-like container wherein a particulate damping member is packed so that the damping material may directly come in tight contact with the inner wall of the electrophotographic photoreceptor or through an elastic member.