Patent ID: 7565098

Claim:
A developing device, comprising: a developer carrier opposed to an image carrier configured to carry an electrostatic latent image; and a rotatable developer transferring screw configured to transfer developer to the developer carrier and configured to agitate the developer, wherein the developer carrier includes a magnet roller and a developing sleeve that includes a rotatable non-electromagnetic cylinder body such that the magnet roller is disposed coaxially within the rotatable non-electromagnetic cylinder body, wherein an axial diameter of a center portion of the rotatable developer transferring screw is greater than an axial diameter of each of both end portions of the rotatable developer transferring screw, wherein the rotatable developer transferring screw includes two blades which are spirally arranged around a center axis of the rotatable developer transferring screw, and wherein the developing sleeve includes a plurality of random ellipsoidal dents on a surface of the developing sleeve.