Zeon Corporation

Toshihiko Yamato

Hiroshi Nakatani

Hiroto Kidokoro

Nobuyasu Ota

The color toner for developing electrostatic latent images comprising a colored resin particle containing at least a binder resin, a colorant, a charge control agent and a parting agent, wherein an extracted liquid with water by means of a hot water extraction method from said colorant has a pH value in the range from 6.0 to 8.0, said colored resin particle has a volume average particle diameter (Dv) in the range from 4 to 10 &#x3bc;m and an average circularity in the range from 0.93 to 0.995, an amount of extracted components with methanol is 7% by weight or less, and an amount of residual volatile compounds is 500 ppm or less. The color toner for developing electrostatic latent images has excellent image-reproducibility and environmental durability and can form an image with a stable image density under a high temperature and high humidity condition.

Color toner for developing electrostatic latent image

The present invention relates to a method for manufacturing a toner with adjusted particle size distribution having a step of preparing colored particles that contain a binder resin and a colorant, and a step of classifying the colored particles. In the classification step, a classifier that has a plurality of vane-wheel classifying rotors coaxially in a casing, enables the rotating speed of each classifying rotor to be set to be the same as or different from each other, and can simultaneously perform a plurality of stages of classification corresponding to each classifying rotor is used; and the powder material comprising colored particles to which a fluidizing agent is added is fed to the classifier to perform classification.

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Tokyo, Japan

Toshihiko Yamato