Toner for developing electrostatic image and two-component type developer for developing electrostatic image

摘要

A toner and a two-component developer for developing electrostatic images are disclosed. The toner comprises toner particles and the two-component developer comprises the toner and a carrier. The toner particle has a two-layer structure of a core layer and a surface layer, produced by suspension polymerization. The core layer and surface layer are mainly comprised of a resin having a low softening point and a resin having a high softening point, respectively. In the surface layer, a polyester resin having a specific acid value and a specific molecular weight is included to impart an appropriate water absorption to the toner. Due to the appropriate water absorption and superior fluidity, the toner can achieve a speedy rise of charge to give electrostatic charges in a stable quantity over a long period of time, and it can give a high image density and images with superior fine-line reproduction and highlight reproduction.