Patent ID: 7853181

Claim:
A developing unit for visualizing an electrostatic latent image formed on an electrostatic latent image bearer with a toner, comprising: a developer storing portion for storing a developer containing an electrostatically chargeable toner and a magnetic carrier; a developing roller for supplying the toner to an electrostatic latent image bearer on which an electrostatic latent image is formed; and an agitating and conveying portion for agitating and conveying the developer in the developer storing portion, the agitating and conveying portion comprising first and second toner agitating and conveying members that are arranged in series in the axial direction of the developing roller, wherein each toner agitating and conveying member comprises an endless belt with toner agitating blades, the endless belts being rotatably arranged in the developer storing portion with their rotational axes oriented approximately vertically so as to rotate the toner agitating blades approximately horizontally, and wherein the endless belts of the first and second agitating and conveying members are rotated in opposite directions such that they convey toner on the developing roller side of the belts from sides of the developer storing portion toward a central portion of the developer storing portion.