Zeon Corporation

Nippon Zeon Company, Ltd.

Nobuyasu Ota

Kazunori Shigemori

Jun Hasegawa

Kazuhiro Sato

Jun Saito

Tokudai Ogawa

Toshihiko Yamato

Katsuhiro Imai

Hidetoshi Azuma

Ryuji Ota

Hirosi Yamamoto

Yoshihiro Makuta

Toyoko Imai

In a method for manufacturing a polymerized toner, in a washing step after polymerization, colored polymer particles are washed using a continuous pressurizing filter in a circulation washing manner, in which a dispersion containing colored polymer particles obtained in the polymerization step is supplied by pressure to the inlet of the continuous pressurizing filter from a slurry tank that stores the dispersion; the dispersion is filtered in the filter while stirring; the concentrated dispersion is fed back to the slurry tank from the outlet; a washing solution in a quantity equivalent to the quantity of the filtrate filtered by filtration is added to the slurry tank to dilute the filtrate; and the dispersion diluted by the washing solution is circulated in the filter.

Method for manufacturing polymerized toner

A process for producing a polymerized toner, comprising a step 1 of preparing a polymerizable monomer composition comprising at least a polymerizable monomer and a colorant, and a step 2 of polymerizing the polymerizable monomer composition in an aqueous medium to form a colored polymer particles, wherein the step 1 comprises a dispersing step of dispersing the colorant finely in a mixed solution comprising at least a polymerizable monomer and a colorant with a media dispersing machine which comprises a rotor and a media particle separation screen mounted on a driving shaft and is operable to rotate simultaneously in association with rotation of the driving shaft.

Process for producing polymerized toner

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.

Method for manufacturing toner

A method of producing a toner having a process of mixing colored particles and outer-additives by using a mixer with an agitating blade whose shaft portion is sealed with a gas having a flow rate of from 0.4 m /hr to 3 m /hr and which rotates at such a high speed as a peripheral speed at a tip of said agitating blade in a range of from 20 m/sec to 50 m/sec. When the colored particles and outer-additives are mixed with each other, there is no generation of aggregates thereby and the toner can be obtained at a high yield. Therefore the toner which hardly generates a white streak and fog, even after a long period of continuous operation of development of electrophotographs is performed, can be obtained.

Method for producing toner by mixing colored particles and outer-additive by mixer with stirrer of high speed rotation

The invention provides a developer comprising toner particles and a finely particulate polymer, wherein the finely particulate polymer is a finely particulate polymer of core-shell structure, which has a core part formed of a vinyl aromatic hydrocarbon polymer and a shell part formed of a (meth)acrylic ester polymer, and is obtained by a soap-free emulsion polymerization process. The developer has stable flowability and charging properties. The invention also provides such a finely particulate polymer and a preparation process thereof.

Developer and finely particulate polymer

A process for producing a toner for developing an electrostatic image, including the steps of: adding to an aqueous dispersion medium a polymerizable monomer composition comprising at least a polymerizable monomer and a colorant uniformly dissolved or dispersed in the polymerizable monomer, wherein the aqueous dispersion medium containing as a dispersion stabilizer a hardly water-soluble metal hydroxide colloid formed by a reaction of a water-soluble polyvalent metal salt with an alkali metal hydroxide in an aqueous phase; and subjecting the polymerizable monomer composition to suspension polymerization, thereby to produce particles having a volume-average particle size in the range of from 2 to 20 .mu.m and a particle size distribution (a ratio of volume-average particle size/number-average particle size) of not more than 1.6.

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Tokyo, Japan

Nobuyasu Ota