METHOD FOR DEVELOPING ELECTROSTATIC LATENT IMAGE

摘要

PURPOSE:To attain clear image formation excellent in resolution and gradation reproducibility by forming a developer layer as a thin layer and using toner containing binder resin consisting of vinyl group polymer whose ratio of weight average molecular weight to number average molecular weight is a prescribed value or more. CONSTITUTION:When a vibrating electric field is generated in a developing area 15 and a latent image formed on an image carrier 20 is developed with a developer layer containing carrier and toner components and formed on a developer carrier 3, the developer is formed as a thin layer. Toner T containing binder resin consisting of vinyl group polymer whose Mw/Mn to be the ratio of weight average molecular weight Mw to number average molecular weight Mn is >=3.5 for instance. Consequently, the toner T has hard and high insulating characteristics and high frictional electrification with the carrier. Thereby, the toner T is effectively frictionally charged with the carrier coated with resin and the electrostatic power of the carrier with the toner and the developer carrier 3 is increased, so that the scattering of the carrier and the toner can be suppressed and a clear image prevented from fogging or carrier adhesion can be obtained.