Patent ID: 9213269
Filing Date: 2015-12-15
Classification: G03G

Abstract:
1. A developing device comprising: a first developing roller that is disposed to be rotatable with a desired distance set between the first developing roller and an outer circumferential surface of a rotatable latent image holding member, transports a developer onto an outer circumferential surface thereof, on which a plurality of grooves extend in a direction parallel to an axial direction of the first developing roller, while holding the developer by magnetic force, and has a substantially cylindrical shape, each of the grooves extends from an extreme left end to an extreme right end, and parallel to an axis of the first developing roller; and a second developing roller that is disposed to be rotatable with desired distances set between the second developing roller and the respective outer circumferential surfaces of the corresponding latent image holding member and the corresponding first developing roller at a position on the downstream side of the first developing roller in a rotation direction of the latent image holding member, transports the developer onto an outer circumferential surface thereof, on which a plurality of grooves extending in a direction parallel to an axial direction thereof are formed, while holding the developer by magnetic force, and has a substantially cylindrical shape, wherein the number of grooves on the second developing roller is not less than 1.3 times the number of grooves on the first developing roller.