Kao Corporation

Shinichiro Omatsu

Hiroshi Ito

Tomihiro Kurosaki

Takashi Imamura

Mitsuharu Masuda

Tetsuhiro Semura

Shunji Arita

A process for preparing a toner comprising the steps of (1) pulverizing a pulverized product of a composition comprising a resin binder and a colorant with a jet type pulverizer in the presence of fine inorganic oxide particles, to give an upper limit cut-off classification powder; and (2) classifying the upper limit cut-off classification powder with a classifier, the classifier comprising a classifying rotor comprising a driving shaft arranged in one casing as a central shaft thereof in a vertical direction, and a stationary spiral guiding vane arranged to share the same central shaft as the classifying rotor, wherein the stationary spiral guiding vane is arranged in a classification zone on an outer circumference of the classifying rotor with a given spacing to the outer circumference of the classifying rotor. The toner obtained according to the present invention can be used for, for example, developing a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method, or the like.

Process for preparing toner

The toner for full-color electrophotography usable for a fixing process by a heat roller, wherein a releasing oil is not applied on a surface of the heat roller, includes at least (a) a binder resin having as a main component a linear polyester obtainable using one or more monomers selected from the group consisting of saturated or unsaturated, aliphatic dicarboxylic acids, acid anhydrides thereof, and lower alkyl esters thereof as an acid component, provided that the saturated aliphatic dicarboxylic acids have carbon atoms of not less than 3, and that the unsaturated aliphatic dicarboxylic acids have carbon atoms of not less than 5, the linear polyester having a softening point of from 90.degree. to 120.degree. C. determined by 'koka' type flow tester; (b) a releasing agent comprising carnauba wax; and (c) a coloring agent. The method for forming fixed images for full-color electrophotography includes the steps of forming an unfixed image by using three or four kinds of toners on a recording medium in single or more toner layers wherein said toners include at least one toner for full-color electrophotography of the present invention; and fixing by heat and pressure the unfixed image using a heat roller without a device for applying a releasing oil.

Toner for full-color electrophotography and method for forming fixed

An alkali metal monoalkylphosphate having a saturated or unsaturated straight-chain or branched hydrocarbon group having from 8 to 32 carbon atoms is described; also described is a process for preparing particles of said alkali metal zinc monoalkylphosphate and cosmetics containing said particles.

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Wakayama, Japan

Shinichiro Omatsu