PURPOSE: To dissolve stuck excess developer and fixed and accumulated toner, and to surely remove it by press-injecting developer solvent into a cleaning roller, allowing it to exude at the outer peripheral face, and to come in contact with a drum.

CONSTITUTION: A cleaning roller 2 is a hollow cylindrical body where the developer solvent can be press-injected, and constituted of a material which is expanded to a radius direction to the outside, and into which the developer solvent can be infiltrated, when the developer solvent is press-injected into the inside of the cleaning roller 2. Then, the outer peripheral face of it comes in contact with a drum 1 in a state in which the cleaning roller 2 is expanded. Therefore, when the developer solvent is press-injected into the cleaning roller at the time of cleaning the drum 1, the press-injected developer solvent exudes from the inside to the outer peripheral face, the cleaning roller 2 comes in contact with the drum 1, and dissolves and removes the toner fixed and accumulated on the outer peripheral face of the drum while making the outer peripheral face wet. Thus, the drum 1 can be cleaned without parting the cleaning roller 2 from the drum 1 by a specific mechanism.