Patent ID: 7123864

Claim:
A toner supply device for supplying toner to a surface of an electrostatic transport member which conveys the toner by generating a progressive wave electric field to a developing position facing a latent image carrying member and develops a latent image on the latent image carrying member by the toner, comprising receiving means for receiving a mixture of toner composed of toner particles and a friction facilitating material composed of friction facilitating particles of an average particle diameter greater than an average particle diameter of the toner particles; agitating and carrying means for agitating and carrying the mixture of the toner and the friction facilitating material in the receiving means, the agitating and carrying means comprising first and second agitating members; and a mesh having plural openings for communicatively connecting inside and outside of the receiving means therethrough, the shortest diameter portion of the openings of the mesh being greater than the average particle diameter of the toner particles and smaller than the average particle diameter of the friction facilitating particles, wherein the toner particles in the mixture are discharged from the openings of the mesh and supplied to the surface of the electrostatic transport member, and wherein the first agitating member is configured to discharge the toner through the mesh to the electrostatic transport member, and the second agitating member is configured to convey toner previously delivered to the developing position and not used to develop the latent image to be mixed with the toner in the receiving means.