Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Process of making developer composition
Patent
1992-06-08
1995-01-24
Rodee, Christopher D.
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Process of making developer composition
430110, 524460, G03G 9087
Patent
active
053842260
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a process for producing a toner for developing an electrostatic latent image formed in an electrophotography method, an electrostatic recording method, an electrostatic printing method and the like. More particularly, it relates to a process for producing a toner composition having small particle size and small particle size distribution in high yield by a simple process, said toner composition containing a release agent component in toner particles by formulating an acrylic resin-grafted polyolefin upon a non-aqueous dispersion polymerization.
BACKGROUND
As a method for producing a polymerized toner, for example, there is proposed a suspension polymerization method wherein a polymerizable composition is dispersed in an aqueous medium and then polymerized, as described in Japanese Patent Kokai 1-201676. This suspension polymerization method requires no pulverization, and a colorant and an additive are uniformly dispersed in comparison with a conventional method.
However, a polymerized toner obtained by this method normally has a large particle size (5 to 15.mu.) and has large particle size distribution. Therefore, a classifying step is required. When a toner having small particle size (3 to 7.mu.) which has recently been required is produced, yield is lowered.
As a method for producing a toner having a small particle size, for example, there is proposed a method based on a non-aqueous dispersion polymerization which comprises polymerizing vinyl monomers in the presence of a colorant in a dispersion solvent to which the vinyl monomers are soluble and polymerized particles therefrom are insoluble, as described in Japanese Patent Kokai Nos. 61-273552 and 62-73276.
However, in this method, there is not disclosed an improvement for finely dispersing a colorant and an additive to polymerize them and, therefore, it is remarkably difficult to allow a release agent which prevents a toner from adhering to a fixing roll to be uniformly present in polymerized particles. The release agent has no affinity with a dispersion solvent and, therefore, the release agent agglomerates in a polymerization system and deposits apart from polymerized particles, whereby, it is not practicable to contain the release agent in polymerized particles.
In Japanese Patent Kokai No. 1-137264, there is disclosed a technique for encapsulating a release agent and a polymer in toner particles, however, all possible production processes are listed and a suitable one is not specified. The polymer component described therein is not uniformly dissolved or dispersed in a dispersion solvent. Therefore, it is difficult to uniformly contain the release agent in polymerized particles, whereby, the resulting toner has large particle size distribution and comparatively large particle size.
DISCLOSURE OF THE INVENTION
An object of the present invention is to provide a process for producing toner particles having small particle size and small particle size distribution which uniformly contain a polyolefin wax in high yield by a simple process.
It has been found that, if polyolefin wax is stably present in a polymerization solvent in a fine dispersion state, the above object can be obtained, and the present invention has been completed.
That is, according to the present invention, there is provided a process for producing a toner which comprises dissolving or dispersing a polymerizable composition comprising: deposition occurs when the acrylic resin-grafted polyolefin (II) is dissolved or dispersed in a mixed solution of one volume of the vinyl monomer (I) and two or more volumes of the dispersion solvent.
As the vinyl monomer (I) used in the present invention, for example, there are ethylenically unsaturated monoolefins such as ethylene, propylene, butylene, isobutylene and the like; halogenated vinyls such as vinyl chloride, vinylidene chloride, vinyl bromide, vinyl fluoride and the like; vinyl esters such as vinyl acetate, vinyl butyrate and the like; (meth)acrylates such as methyl (meth)acrylate, et
REFERENCES:
patent: 3876610 (1975-04-01), Timmerman et al.
patent: 4777104 (1988-10-01), Matsumoto et al.
NIPA, Japanese Patents Abstracts, Week 8938, Derwent, AN 89-275345 (38), JP-A-1,201,676 (Aug. 14, 1989).
Kanakura Akihiro
Kishida Takahito
Maruta Masayuki
Yabuuchi Naoya
Nippon Paint Co. Ltd.
Rodee Christopher D.
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