Patent ID: 8909106

Claim:
A developing device for forming a toner image on an image support member with a developer composed of toner and carriers, said developing device comprising: a main body in which a first space for a developer is made; a developer support member, which is located in the first space, for supporting the developer and for supplying toner of the developer to the image support member; and a toner tank in which a second space for toner is made, the second space leading to the first space via at least one boundary area; wherein the at least one boundary area between the first space and the second space is closed by the toner or the developer; wherein the at least one boundary area between the first space and the second space is located above a center of the developer support member; wherein the developer support member is a developing roller that rotates in a specified direction; wherein the developing device further comprises a blade, which is located upstream, with respect to the specified direction, from a closest point where the developing roller and the image support member are closest to each other, for regulating a developer layer supported on a peripheral surface of the developing roller to a specified thickness; and wherein the at least one boundary area between the first space and the second space is located upstream, with respect to the specified direction, from the blade.