PURPOSE: To obtain a toner having satisfactory image characteristics, excellent in image quality, keeping stable image characteristics even by continuous copying, hardly contaminating the interior of a machine and ensuring superior durability by specifying the relation between the content of an electrostatic charge controlling agent in a toner before pulverization and that after classification.
CONSTITUTION: This toner contains a resin, a colorant and an electrostatic charge controlling agent, and the content (Ca) of the electrostatic charge controlling agent in this toner before pulverization and the content (Cb) of the electrostatic charge controlling agent in this toner after classification satisfy the relation of Ca-Cb/Ca(=Kα)≤0.2. In the case of Kα>0.2, the stability of image quality is deteriorated and the interior of a machine is contaminated. The average particle diameter (Dr) of the resin is 30-3,000μm, the average particle diameter (Dc) of the electrostatic charge controlling agent is ≤100μm and the ratio of Dc to Dr is ≤2. In the case of <30μm average particle diameter, the mixability of the resin with the other materials is inferior and flowability at the time of feeding starting materials and miscibility at the time of kneading are deteriorated. In the case of >3,000μm, starting materials are liable to cause uneven distribution at the time of feeding.
SUEYOSHI TOSHIYUKI
TAKAHASHI NORIAKI
ONOE HIROYUKI
