An electrophotographic photoreceptor with excellent wear resistance and high durability, and an image formation method having a high toner transferring efficiency and capable of providing images with high quality. The thrust generating section is made up of a flexible shaft adapted to rotate clockwise or counterclockwise around a shaft axis. Each rod is inserted into a separate tube with its movement restricted by rod lock. Sonic energy is introduced into the liquid and travels through the liquid to the workpiece, to assist in processing.