JPS5938583B2 - Toner for developing electrostatic images and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a toner for developing electrostatic images in electrophotography, electrostatic recording, electrostatic printing, etc., and a method for producing the same.

Conventional methods for developing electrostatic images formed on a recording medium in processes such as electrophotography, electrostatic recording, or electrostatic printing can be broadly divided into methods that involve finely dispersing various pigments and dyes in an insulating liquid. A fine powder developer called a toner containing a colorant dispersed in a natural or synthetic resin, such as a liquid development method using a liquid developer, a cascade method, a hand brush method, a magnetic brush method, an impression method, and a powder cloud method. There is a so-called dry developing method using the above method, and the present invention relates to a toner used in the latter dry developing method.

Conventionally, toners for developing electrostatic images are manufactured by melt-kneading a soft polymer and a colorant, dispersing the colorant in the polymer, and finely pulverizing the colorant-dispersed polymer. The particle size distribution of the fine powder obtained by this method is very wide, and in order to obtain a toner that can be put to practical use, it must be further subjected to a classification step, and the method itself is complicated and costly. There are drawbacks.

On the other hand, methods for directly obtaining colored polymer fine particles without a pulverization step include, for example, Japanese Patent Publications No. 36-10231, No. 47-51830, No. 51-14895;
No. 3-17735, No. 53-17736 and No. 53
As described in each publication of No. 17737, a polymerization method has been proposed.

These are based on the so-called suspension polymerization method, in which a polymer composition containing a polymerizable monomer, a polymerization initiator, and a colorant is suspended in an aqueous dispersion medium and polymerized to directly produce toner. It is something to do.

This method has the advantage that the toner particles produced are spherical and have excellent fluidity, and the manufacturing process is simple and the cost is low.

However, in this production method, charge control agents that affect the polymerization reaction cannot be used, and even if they can be used, they are sold in bulk, making it difficult to produce toners with satisfactory charge control properties. It has the disadvantage of not being able to Further, the toner obtained by this method has a drawback that it is highly dependent on humidity and has low moisture resistance and charging property. This is because, in the suspension polymerization process, a dispersion stabilizer is produced, which is essential to be present in the dispersion medium in order to prevent particles of the dispersed polymer composition from coalescing and increasing the particle size. This is because it comes to exist on the surface of the polymer particles. Specifically, there are two main methods for dispersion stabilization in suspension polymerization, one of which is to dissolve a water-soluble polymeric substance in a dispersion medium. With this method, a dispersion stabilizing effect can be obtained using a relatively small amount of dispersion stabilizer, but since the water-soluble polymer substance is adsorbed or grafted onto the surface of the polymer particles being produced, repeated washing with water after polymerization is not necessary. It is difficult to completely remove it. Another method is to suspend a sparingly soluble inorganic compound in a dispersion medium, but when a sparingly soluble inorganic compound is used alone, as described in Japanese Patent Publication No. 47-51830, 25 A large amount of poorly soluble inorganic compound (~100 parts by weight) must be used, and it is extremely difficult to completely remove it. It will remain to some extent.

However, the electrical properties of toner used in dry electrophotography or electrostatic recording mostly depend on its surface, and in this way water-soluble polymeric substances or sparingly soluble inorganic salts remain on the surface of polymer particles. As a result, for example, the electrical conductivity and humidity dependence of the water-soluble polymer itself directly affect the electrical properties of the toner, resulting in a drawback that the triboelectric charging properties of the toner become extremely unstable.

The present invention has been made in order to overcome the various drawbacks of the toner produced by the pulverization method and the polymerization method described above, and an object of the present invention is to provide a toner having excellent triboelectric charging characteristics and excellent moisture resistance. An object of the present invention is to provide a toner for developing an electrostatic image that has the properties.

Another object of the present invention is to provide a method for producing the above-mentioned toner for developing electrostatic images.

In order to achieve the above object, in the present invention, polymer particles obtained by polymerizing a polymer composition containing a polymerizable monomer, a colorant, and a necessary toner property improver are used as toner cores. As particles, these are mixed and dispersed in a 1 to 40 W% latex aqueous solution, and by adding a water-soluble inorganic salt to the intoxicant or changing the pH of the solution, emulsion polymerization is carried out on the surface of the core particles. A toner for developing an electrostatic image is obtained by forming a coating layer consisting of fine particles formed by the above method. To explain the above method for producing core particles for toner, first, a polymer composition containing a polymerizable monomer, a colorant, etc. as components is prepared, and the polymer composition is added to an aqueous dispersion medium containing a dispersion stabilizer. The polymerizable monomers are polymerized in a dispersed and suspended state, whereby the particle size is 1 to 5.
Toner core particles consisting of 0 micron spherical particles are produced.

The polymer composition may optionally contain a colored polymerization initiator for the polymerizable monomer, a crosslinking agent to prevent damage, a reactive prepolymer, and a low molecular weight polyolefin. Furthermore, when a one-component magnetic toner is finally obtained, magnetic particles are added.
In the above-mentioned polymerization method, the polymer composition is dispersed and suspended in a dispersion medium such as water as dispersed particles of a desired particle size by mechanical stirring, and polymerization is carried out, but as the polymerization progresses, the dispersed particles become sticky. It is necessary to prevent particles from coalescing into large particles by increasing their properties, and a dispersion stabilizer is used for this purpose.

The materials used as such dispersion stabilizers are generally divided into water-soluble polymeric substances and fine powders of poorly soluble inorganic compounds.The former includes gelatin, starch, polyvinyl alcohol, and others, and the latter includes It includes sparingly soluble salts such as barium sulfate, calcium sulfate, barium carbonate, calcium carbonate, and calcium phosphate, inorganic polymer substances such as talc, viscosity, silicic acid, and diatomaceous earth, metal oxides, and other powders. As the polymerizable monomer according to the present invention, any polymerizable monomer can be used, and it may be a self-polymerizable vinyl monomer, and for example, it can be used to produce a polyester resin. Although monomers such as dibasic acids and glycols may be used, vinyl monomers are preferred.

Specific examples of the polymerizable monomer according to the present invention are listed below.

For example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-ethylstyrene, 2.
4-dimethylstyrene, p-n-butylstyrene, p-
Tert-butylstyrene, p-n-hexylstyrene, p-n-octylstyrene, p-n-nonylstyrene, p-n-decylstyrene, p-n-dodecylstyrene, p-methoxystyrene, p-phenylstyrene ,p-
Examples include styrene and styrene derivatives such as chlorstyrene and 3,4-dichlorostyrene, and styrene monomers are most preferred.

Other vinyl monomers include, for example, ethylenically unsaturated monoolefins such as ethylene, propylene, butylene, and isobutylene; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide, and vinyl fluoride; vinyl acetate; Vinyl esters such as vinyl propionate, vinyl benzoate, vinyl butyrate, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, probyl acrylate, n-octyl acrylate,
Dodecyl acrylate, 2-ethylhexyl acrylate,
stearyl acrylate, 2-chloroethyl acrylate,
Phenyl acrylate, methyl α-chloroacrylate, methyl methacrylate, ethyl methacrylate, probyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, methacrylate α-methylene aliphatic monocarboxylic acid esters such as 2-ethylhexyl acrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, and diethylaminoethyl methacrylate; acrylics such as acrylonitrile, methacrylonitrile, and acrylamide Acid or methacrylic acid derivatives: Vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether; Vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, methyl isopropenyl ketone; N-vinyl pyrrole, N-vinyl carbazole, N
-N- such as vinyl indole and N-vinylpyrrolidone
Vinyl compounds: Vinylnaphthalenes and the like can be mentioned. These vinyl monomers may be used alone or may be used in combination to form a copolymer.

Examples of dibasic acids used as monomers for obtaining polyester resins include terephthalic acid, isophthalic acid, adipic acid, maleic acid, succinic acid, sebacic acid, thioglycolic acid, diglycolic acid, and glycols. Examples include ethylene glycol, diethylene glycol,
1●4-bis(2-hydroxyethyl)benzene, 1.
Examples include 4-cyclohexanedimethanol and propylene glycol.

As a monomer to obtain polyamide resin, prolactam,
Furthermore, examples of dibasic acids include terephthalic acid, isophthalic acid, adipic acid, maleic acid, citric acid, sebacic acid, and thioglycolic acid, and examples of diamines include ethylenediamine, diaminoethyl ether, Examples include 1,4-diaminobenzene and 1,4-diaminobutane.

Examples of diisocyanates used as monomers for obtaining polyurethane resin include p-phenylene diisocyanate and p-phenylene diisocyanate.
Examples include xylene diisocyanate and 1,4-tetramethylene diisocyanate, and examples of glycols include ethylene glycol, diethylene glycol, propylene glycol, and polyethylene glycol.

As a monomer for obtaining a polyurea resin, examples of diisocyanates include p-phenylene diisocyanate, p-xylylene diisocyanate, and 1,4 tetramethylene diisocyanate, and examples of diamines include ethylene diamine and diaminoethyl ether. , 1・
Examples include 4-diaminobenzene and 1,4-diaminobutane.

As monomers for obtaining epoxy resin, amines include:
Ethylamine, butylamine, ethylenediamine, 1.
Examples of diepoxies include diglycidyl ether, ethylene glycol diglycidyl ether, bisphenol A diglycidyl ether, and hydroquinone diglycidyl ether. can be mentioned.

The method for producing core particles for toner of the present invention includes a process of polymerization in the synthesis of a polymer that is a binder resin of a toner.
For example, a suspension polymerization method, an emulsion polymerization method, a bulk polymerization method, a solution polymerization method, etc. are used, and addition polymerization, condensation polymerization, ring-opening polymerization, etc. are used as the reaction type of polymerization.

In addition, during the polymerization process of the polymerizable monomer, a colorant and a charge control fluidizing agent, which is a toner characteristic imparting agent, can be added, and after the polymerization is completed, it is granulated so that it can be used as a toner. Alternatively, after the polymerization of the polymerizable monomers is completed, a coloring agent and the like can be mixed, ground, cooled, and crushed to produce a toner. For example, when using a vinyl resin obtained by polymerizing α/β monounsaturated polymerizable monomers, 5 to 95 parts by weight of a polymerization initiator and, if necessary, a prepolymer are added to 100 parts by weight of the polymerizable monomer. part, colorant 1-2
After adding 0 parts by weight, polymerization is carried out in a nitrogen stream at 600 to 120° C. without a solvent by a conventional method to obtain a polymer. Suspension polymerization is carried out by a conventional method in water in the presence of the above-mentioned dispersant, or water-soluble polymerization is carried out in the presence of a surfactant such as sodium dodecylbenzenesulfonate, an alkyl sulfate type anionic emulsifier, or sodium dodecylsulfonate. Either emulsion polymerization is carried out in a conventional manner at 40 to 90°C using an initiator under a nitrogen stream, or ordinary bulk polymerization is carried out, or the bulk polymerization recipe is mixed with a suitable solvent (e.g. benzene, xylene, ethanol, etc.). (methyl ethyl ketone, etc.) and solution polymerization by a conventional method to obtain a polymer. When the polymer according to the present invention is a condensation polymer or an addition polymer, a general dibasic acid and a glycol are heated to 100 to 180°C in the presence of a strong acid (e.g. sulfuric acid, p-toluenesulfonic acid, etc.). Alternatively, polyester resin can be made by a synthesis method that involves a heating reaction under reduced pressure. Further, a normal polyamide resin can be produced by reacting a dibasic acid and a diamine salt in a heated molten state at 140 to 200°C.

Further, a phenol-formalin resin can be obtained by a usual method of heating to 100 to 150° C. in the presence of formalin, phenols, and a strong acid or base catalyst.

Also, in the presence of glycol and diisocyanate, 50~
Polyurethane resin can be produced by the usual method of heating and reacting at 150°C.

It is also possible to produce polyurea resin by the usual method of reacting diamine and diisocyanate at 20 to 100°C. When the polymer according to the present invention is a ring-opening polymer, an epoxy resin can be prepared by a conventional method by reacting a diamine and a diepoxy compound at 50 to 120°C.

The polymerizable monomer used in the present invention may be used alone, but
Various combinations of self-polymerizable monomers and other polymerizable monomers may be used.

The polymer according to the present invention obtained as described above can be used as fine toner core particles that can be put to practical use as is, or the polymer can be pulverized using a pulverizer and classified using a zigzag classifier, for example. Either the method may be used to produce toner core particles, or the toner core particles may be produced by mixing this polymer with a coloring agent and the like, kneading it in a mill, cooling it, and pulverizing it.

The polymer according to the invention may be a crosslinked polymer.

This crosslinked polymer may be one that undergoes self-crosslinking polymerization, such as a prepolymer (in this case, the monomer that undergoes self-crosslinking polymerization may be used in combination with other monomers), or a polymerizable monomer. A crosslinking agent may be present during the polymerization. As the crosslinking agent used in the present invention, any known crosslinking agent can be used as long as it crosslinks and polymerizes the polymerizable monomer according to the present invention.

This crosslinking agent is preferably a compound having at least two polymerizable vinyl groups. Specifically, aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene, and derivatives thereof: ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, trimethylolpropane triacrylate, allyl methacrylate, t-butylamino Diethylenically unsaturated carboxylic acid esters such as ethyl methacrylate, tetraethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, N-N divinylaniline, divinyl ether,
All divinyl compounds such as divinyl sulfide and divinyl sulfone and compounds having three or more vinyl groups can be used alone or in combination of two or more.

Furthermore, ethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 14-butenediol, 1,4-bis(hydroxymethyl ) Dihydric alcohols such as cyclohexane, bisphenol A1 hydrogenated bisphenol A1 polyoxyethylenated bisphenol A1 polyoxypropylenated bisphenol A: maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, Dibasic acids and their derivatives, such as geltaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, malonic acid, their non-permanent acids or their esters with lower alcohols: Trivalent or higher alcohols such as glycerin, trimethylolpropane, and pentaerythritol, and trivalent or higher carboxylic acids such as trimellitic acid and biromellitic acid are used as crosslinking agents in the present invention. The amount of such a crosslinking agent added to the polymerizable monomer is selected in the range of 0.005 to 20 parts by weight, preferably 0.1 to 5 parts by weight.

If the amount added is too large, the toner becomes insoluble and infusible, and the fixing properties for toners tend to be poor. If the amount added is too small, it becomes difficult to impart the characteristics of toner such as durability, storage stability, and abrasion resistance. . In the present invention, a polymer is obtained by polymerizing a polymerizable monomer, and a polymerization initiator may be used during the polymerization.

Examples of the polymerization initiator include lauroyl peroxide, benzoyl peroxide, 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), orthochlorobenzoyl peroxide, and orthochlorobenzoyl peroxide. Methoxybenzoyl peroxide is mentioned. The core particles for toner according to the present invention are obtained by the above-mentioned removal and used as core particles for toner. superplasticizer,
A prepolymer, a mold release agent, a fluidizing agent, a magnetic material, another binder resin, etc. may be added as toner property improving agents.

When a prepolymer is used in the toner core particles according to the present invention, fixing properties such as toner storage stability, moisture resistance, charging properties, and offset prevention effect in a roller fixing method are further improved. The prepolymer used in the present invention is preferably a reactive prepolymer, and the reactive prepolymer is a prepolymer having a group capable of reacting with the functional group of the polymerizable monomer according to the present invention.

These reactive groups include carboxy groups (-CO
OH), sulfo group (-SO3H), ethylene\imino group N-(R, and R2 are hydrogen 1-1/atom,
Alkyl group such as methyl group)1. Isocyanate group (0C
N-), double bond group (-CH-CH), acid anhydride (V epoxy group (0MtSYH-)...Rogen atom etc. are typical)
- Listed as -.

The reaction between the reactive group of the prepolymer and the monomer described above is as follows:
These include those that react upon mere mixing, those that react in the presence of a catalyst such as a polymerization initiator, and those that react upon light irradiation such as a cinnamoyl group.

These prepolymers may have any molecular weight, but are usually 1000 or more, and even 20
00-2000000, details 5000-1000
000 molecular weight is generally used.

Typical specific examples of these prepolymers are listed below.

[For those having an epoxy group,]

In addition to the above, poly-1/2-butadiene, a
- Butadiene-based prepolymers such as ω-polybutadiene glycol, maleated polybutadiene, and acrylic-terminated polybutadiene can also be used.

The amount of prepolymer added may be used in any ratio, but is preferably 5 to 95 parts by weight, particularly preferably 10 to 70 parts by weight, per 100 parts by weight of the polymerizable monomer. It may not contribute to the offset prevention effect and the improvement of the fixing properties of the toner, and if it exceeds 95 parts by weight, the tackiness tends to be excessive, which may affect the storage stability of the toner.
This is undesirable since it tends to deteriorate the fluidity and increase the offset phenomenon.

Any coloring agent such as a pigment or dye can be added to the toner core particles according to the present invention at the time of polymerization of the polymerizable monomer or after obtaining the polymer, if necessary.

These coloring agents are known ones, such as carbon black, nigrosine dye, aniline blue, calco oil blue, chrome yellow, ultramarine blue,
DuPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, oil black,
Azo oil black, rose bengal and mixtures thereof. The amount of the colorant used in the present invention may vary widely, and is usually 1 to 20 parts by weight per 100 parts by weight of the polymerizable monomer.

If a coloring agent is added after obtaining the polymer, it may be added in the same manner as described above.

When the toner of the present invention is used in a roller fixing method (particularly a hot roller fixing method), a release agent can be added to the toner core particles to prevent offset.

Various types of release agents are known, and the most preferred is a low molecular weight olefin polymer. This low molecular weight olefin polymer is an olefin polymer containing only olefin as a monomer component or an olefin copolymer containing a monomer other than olefin as a monomer component, and has a low molecular weight. .

Olefins as monomer components include, for example, ethylene,
Propylene, 1-1 butene, 1-1 benzene, 1-1 hexene
, heptene-1, octene-1, nonene-1, decene-1 or their homologues with different positions of the unsaturated bond or, for example, 3-methyl to 1-butene, 3-methyl-
All kinds of olefins such as 2-benzene, 3-propyl-5-methyl-2-hexene, etc. into which an alkyl group is introduced as a branch chain are included. Monomers other than olefin that form a copolymer with olefin include vinyl ethers such as vinyl methyl ether, vinyl n-butyl ether, vinyl phenyl ether, vinyl acetate, vinyl butyrate, etc. vinyl esters such as vinyl fluoride,
vinylidene fluoride, 4-ethylene fluoride, vinyl chloride,
Halogenated olefins such as vinylidene chloride and 4-monoethylene chloride, such as methyl acrylate, ethyl acrylate, n-butyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, stearyl methacrylate , acrylic esters or methacrylic esters such as N-N-dimethylaminoethyl methacrylate and t-butylaminoethyl acrylate; acrylic type derivatives such as acrylonitrile and N·N-dimethylacrylamide, such as acrylic acid; , organic acids such as methacrylic acid, maleic acid, fumaric acid, and itaconic acid, diethyl fumarate, and β-pinene.

The low molecular weight olefin polymer used in the present invention is an olefin polymer consisting only of olefins containing at least two or more of the above-mentioned olefins as monomer components, such as ethylene-propylene copolymers, ethylene-butene copolymers, Ethylene-pentene copolymer, propylene-butene copolymer, propylene-pentene copolymer, ethylene-3-methyl-1-butene copolymer, ethylene-propylene-butene copolymer, etc., or at least the above-mentioned olefins. olefin copolymer containing as a monomer component at least one of the above-mentioned monomers other than olefin, such as ethylene vinyl acetate copolymer, ethylene-vinyl methyl ether copolymer, and ethylene monochloride. Vinyl copolymer, ethylene-methyl acrylate copolymer, ethylene-methyl methacrylate copolymer, ethylene-acrylic acid copolymer, propylene monovinyl acetate copolymer, propylene-vinylethyl ether copolymer, propylene - ethyl acrylate copolymer, propylene-methacrylic acid copolymer, butene-methyl methacrylate copolymer, benzene monovinyl acetate copolymer,
These include hexene vinyl monobutyrate copolymer, ethylene-propylene monovinyl acetate copolymer, ethylene monovinyl acetate-vinyl methyl ether copolymer, and the like.

Among the low-molecular-weight olefin polymers used in the present invention, those containing monomers other than olefin as monomer components preferably contain as much of the olefin component as possible in the copolymer.

This is because, in general, as the content of the olefin component decreases, the mold releasability decreases, and characteristics such as toner fluidity and image quality tend to deteriorate. Therefore, it is desirable that the content of the olefin component in the copolymer be as high as possible, and in particular, a copolymer containing about 50 mol% or more of the olefin component is effectively used in the present invention. The low molecular weight polyolefin polymer used in the present invention has a softening point of 10
0 minutes to 180°C, particularly those having a temperature of 1300 to 16°C are preferred.

The amount of the low molecular weight polyolefin polymer used in the present invention is 1 to 20 parts by weight per 100 parts by weight of the resin component of the toner.
The amount is preferably 3 to 15 parts by weight, and if it is less than 1 part by weight, it may not have a sufficient offset prevention effect, and if it is more than 20 parts by weight, it may gel during polymerization, which is not preferable.

When the toner of the present invention is used as a one-component developer, any magnetic material can be added. This magnetic material is acidic,
Any neutral or basic magnetic substance can be used, but when it is present during monomer polymerization, it has a pH of 6 or higher, preferably a pH of 6 or higher.
A magnetic material having a value of 6 to 10 is preferable. The magnetic material used in the present invention is a material that is strongly magnetized in the direction of a magnetic field, is preferably black in color, is well dispersed in the resin, is chemically stable, and has a particle size of Magnetite (triiron tetroxide) is most preferred because it is desirable that fine particles of 1 μm or less can be easily obtained.

Typical magnetic or magnetizable materials include metals such as cobalt, iron, and nickel; aluminum cobalt;
Alloys and mixtures of metals such as copper, iron, lead, magnesium, nickel, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium: aluminum oxide, iron oxide, oxide copper, nickel oxide, zinc oxide,
Metal compounds containing metal oxides such as titanium oxide and magnesium oxide; refractory titrides such as panadium titanide and chromium titride; carbides such as tungsten carbide and silica carbide; ferrites and mixtures thereof, etc. are used. can get. These ferromagnetic materials have an average particle size of 0
．． It is desirable that the amount is about 1 to 1 μm, and the amount contained in the toner is desirably about 50 to 300 parts by weight per 100 parts by weight of the resin component, particularly preferably about 100 parts by weight of the resin component.
It is 90 to 200 parts by weight. The toner core particles according to the present invention can be obtained as described above, but when the monomers are polymerized or when the toner core particles are produced after the polymer is obtained, known binders for toners are used. Agent resins may be further combined.

In either case, the average particle size of the toner core particles according to the present invention is the same as that of commonly used toners, and is preferably in the range of 7 to 30 microns.

If large particles of 50 microns or more are included, the image quality will be significantly degraded, and if fine powder particles of 1 micron or less are included, the surface of the photoreceptor will be contaminated by the fine powder particles, the sensitivity of the photoreceptor will decrease, and the image will deteriorate. This is not preferable because the following phenomena occur. A specific example of the method for producing toner core particles according to the present invention will be described below.

Hereinafter, "parts" refer to "parts by weight" unless otherwise specified. A polymer composition was prepared by mixing and dispersing the above substances.

On the other hand, 3.0 parts of aluminum oxide-C (manufactured by Dexa Corporation) and 0.03 parts of sodium dodecylbenzenesulfonate were placed in a separable flask with a capacity of 21, and distilled water was added thereto, and the polymer composition was added thereto. Stirrer “TK Homo Jetter” (manufactured by Tokushu Kika Kogyo Co., Ltd.) rotates at 500 revolutions.
0r. p. m. While stirring, the temperature was raised to 60°C and maintained at this temperature. After that, use a regular stirrer at 10 rotations.
0r. p. m. The polymerization reaction was allowed to proceed for 7 hours while stirring to complete the polymerization, but no change in particle size was observed.
After the polymerization was completed, the solid particles were separated and dried to obtain toner core particle powder A having an average particle size of 13 microns. A polymer composition was prepared by mixing and dispersing the above substances using a sand stirrer.

On the other hand, a 0.001% aqueous solution of sodium dodecylbenzenesulfonate was placed in a separable flask with a capacity of 21.
Add the polymer composition and use a stirrer "TK Homo Mixer"
(manufactured by Tokushu Kika Kogyo Co., Ltd.) with a rotation speed of 5000 r. p
．． m. While stirring, the temperature was raised to 65°C and maintained at this temperature. The particle size range of the dispersed particles after 30 minutes of heating was 10 to 15 microns. After that, the number of revolutions was 100 r using a normal stirring rock. p. m. The polymerization reaction was allowed to proceed for 6 hours while stirring to complete the polymerization, but no change in particle size was observed. After completion of polymerization, hydrochloric acid was added, washed with water, separated and dried to obtain toner core particle powder B having an average particle size of 13 microns.

A polymeric composition was prepared by mixing and dispersing the above substances.

On the other hand, the above polymer composition was added to a 1.0% by weight aqueous polyvinyl alcohol solution in a separable flask with a capacity of 21, and a stirrer "TK Homo Mixer" (manufactured by Tokushu Kika Kogyo Co., Ltd.) was used to 5000r. p. m. While stirring, the temperature was raised to 65°C and maintained at this temperature. The particle size range of the dispersed particles after 30 minutes of heating up is 10 to 1
It was 5 microns thick. Thereafter, the number of revolutions was 100 r using a normal stirrer. p. m. The reaction was allowed to proceed for 6 hours with stirring to complete the polymerization, but no change in particle size was observed.
After the polymerization was completed, the solid particles were separated and dried to obtain toner core particles C having an average particle size of 13 microns.

A polymer composition was prepared by mixing and dispersing the above substances.

On the other hand, the capacity is 2f! 3 parts of hydrophilic colloidal silica Aerosil 1 200 (manufactured by Dexa) was placed in a separable flask and distilled water was added thereto. Co., Ltd.) V
From C, the rotation speed is 5000r. p. m. While stirring, the temperature was raised to 70°C and maintained at this temperature. The particle size range of the dispersed particles after 30 minutes of heating was 10 to 15 microns. Thereafter, the polymerization was completed using an ordinary stirrer at a rotational speed of 1n0rhm and 1tr6g to 4k to complete the polymerization, but no change in particle size was observed.
After the polymerization was completed, the solid particles were separated and dried to obtain toner core particle powder D having an average particle size of 13 microns.

The toner of the present invention is produced by forming a coating layer consisting of fine particles formed by emulsion polymerization on the toner core particles obtained as described above.

Specifically, the toner core particles according to the present invention are mixed and dispersed in a 1 to 40% by weight aqueous latex solution.

Since the latex aqueous solution is an aqueous dispersion of fine polymer particles obtained by emulsion polymerization, by adding a water-soluble inorganic salt to the dispersion or changing the pH of the dispersion, the toner nuclei can be The coating layer is formed by depositing small polymer particles on the surface of the particles. The toner property improving agent added in the toner of the present invention is preferably added to the toner core particles and not added to the coating layer.
The size of the microparticles in the latex is 100 millimicrons or less, usually 50 to 1 millimicrons, and particles of this size are used as the microparticles according to the present invention. The thickness of the coating layer according to the present invention is 100 microns or less, preferably 50 to 1 millimicrons. A specific method for producing microparticles formed by emulsion polymerization is shown below.

The above formulation was added to 11 three-necked flasks equipped with a nitrogen inlet tube, a condenser, and a stirrer, and after the air in the reactor was replaced with nitrogen, the temperature was maintained at 50° C. with stirring.

After heating and stirring for 5 hours, the reaction solution was cooled to room temperature, and this solution was filtered to obtain Latex 1B.

ZO lOl four-headed flask with stirrer, thermometer, drip load,
A nitrogen gas inlet tube and a reflux condenser are installed, and distilled water and sodium dodecylsulfonate are added thereto, and the temperature is raised to 80°C.

After purging with nitrogen, add potassium persulfate all at once, styrene,
The fluorinated pentyl methacrylate mixed solution was added dropwise from the dripping load over a period of 1 hour. After the dropwise addition was completed, the reaction was continued at 80°C for an additional 3 hours. After reacting for a predetermined time, the reaction solution is cooled to room temperature and the pH of the solution is adjusted to 6 with a 14% ammonia aqueous solution.

This solution is filtered and used as latex 1C. To form an image by electrophotography using the toner of the present invention, a selenium photoreceptor or an inorganic photoconductive material such as lead oxide, cadmium sulfide, cadmium selenide, cadmium selenide sulfide, lead oxide, mercury sulfide, etc. A photoreceptor in which a photosensitive layer containing a conductive material dispersed in a binder resin is provided on a conductive support, or an organic photoconductive material such as anthracene or polyvinylcarbazole is dispersed in a binder resin as necessary. A photoreceptor is used in which a photosensitive layer containing the above-mentioned photoreceptor is provided on a conductive support. The surface of the photosensitive layer of such a photoreceptor is entirely charged by corona discharge using, for example, a corotron or scorotron charger, and then imagewise exposed to light or the like to form an electrostatic charge image. This electrostatic charge image is then developed by, for example, a cascade method or a magnetic brush method, with a developer comprising, for example, a mixture of the toner of the present invention and a glass beads or iron powder carrier to form a toner image. This toner image is transferred onto the transfer paper by being pressed against the transfer paper under, for example, corona discharge. The toner image transferred onto this transfer paper is
For example, heat fixing is performed using a heat roll fixing device coated with a fluororesin or silicone rubber having mold releasability. Specific examples of the present invention are shown below.

Example 1 Liquid 5 prepared by adding distilled water to Latex A and adjusting the concentration to 5%.
To 00 parts, 100 parts of a 10% by weight aqueous magnesium sulfate solution was added dropwise to the mixture, and 100 parts of a 10% by weight aqueous magnesium sulfate solution was added thereto while stirring vigorously at room temperature.

After the addition was completed, the contents were sufficiently stirred until the contents were mixed uniformly. Thereafter, a sample of the toner of the present invention having an average particle size of 13 μm was obtained by filtering, washing with water, and air drying. Using a developer prepared by mixing 5 parts of this sample toner of the present invention with 95 parts of "Iron Powder Carrier ZODSP" (manufactured by Dowa Iron Powder Industries Co., Ltd.), an electronic copying machine "UBix" (manufactured by Konishiroku Photo Industries Co., Ltd.) was used. Co., Ltd.)
When image formation was carried out, a clear image was obtained.

Also, when we measured the volume resistivity of this sample of the present invention, it was 2 x 1015Ω? A high value was obtained. Example 2 Liquid 500 prepared by adding distilled water to latex B and adjusting the concentration to 5%
Add 14% ammonia aqueous solution to 20% aqueous ammonia solution while stirring vigorously at room temperature.
The mixture was gradually added dropwise until H reached 10.

After the addition was completed, the contents were sufficiently stirred until the contents were mixed uniformly. Thereafter, a sample of the toner of the present invention having an average particle size of 13 μm was obtained by filtering, washing with water, and air drying. When an image was formed in an electronic copying machine U-BixV using a developer prepared by mixing 5 parts of the sample of the present invention with 95 parts of iron powder carrier DSP, a clear image was obtained.

Also, when we measured the volume resistivity of this sample of the present invention, it was found to be 2×1015Ω? A high value was obtained.

Example 3 To 500 parts of a solution prepared by adding distilled water to latex 1C and adjusting the concentration to 5%, add ClOO parts of toner core particle powder, and add 10% by weight while stirring vigorously at room temperature.
100 parts of an aqueous magnesium sulfate solution was gradually added dropwise.

After the addition was completed, the contents were sufficiently stirred until they were uniformly mixed. After that, by washing with water and air drying, the average particle size was 13 μm.
A sample of the toner of the present invention was obtained. When an image was formed in an electronic copying machine [U-BixV] using a developer prepared by mixing 5 parts of the sample of the present invention with 95 parts of iron powder carrier DSP, a clear image was obtained.

Also, when we measured the volume resistivity of this sample of the present invention, it was 2×1015Ω? A high value was obtained. Example 4 Liquid 500 prepared by adding distilled water to latex A and adjusting the concentration to 5%
A portion of toner core particle powder-DlOO was added to the mixture, and while stirring vigorously at room temperature, a 14% ammonia aqueous solution was gradually added dropwise until the pH reached 10.

After the addition was completed, the contents were sufficiently stirred until they were uniformly mixed.

Then, by filtering, washing with water, and air drying, the average particle size was 1.
A 3μ sample of the toner of the present invention was obtained. When this toner was used as a developer to form an image in an electronic copying machine "U-BixTJ" (manufactured by Konishiroku Photo Industry Co., Ltd.), a clear image was obtained.

Comparative Example 1 5 parts of toner core particle powder A to 95 parts of iron powder carrier D
Electronic copying machine U-B using developer made by mixing with SP
When an image was formed using ixV, the resulting image had significant fog.

Further, the specific volume resistivity of this toner was as low as 5.times.10@9 .OMEGA., and the amount of charge of the developer was as low as -2 microcoulombs/y. Comparative Example 2 When an image test was carried out in the same manner as in Comparative Example 1 using toner core particle powder B, the obtained image had significant fogging.

Further, the specific volume resistivity of this toner was as low as 3.times.10@9 .OMEGA., and the amount of charge was as low as -2 microcoulombs/y. Comparative Example 3 When an image test was carried out in the same manner as in Comparative Example 1 using toner core particle powder C, the obtained image had significant fogging.

Further, the specific volume resistivity of this toner was as low as 5.times.10@9 .OMEGA., and the amount of charge was as low as -3 microcoulombs/y.

Comparative Example 4 Using toner core particle powder D as a developer, an electronic copying machine U-
When an image was formed using BixT, the resulting image had significant fog.

Claims (1)

[Claims] 1. An electrostatic charge characterized by comprising a core particle formed by polymerization and a coating layer made of microparticles formed by emulsion polymerization on the surface of the core particle. Toner for image development. 2. The core particles formed by polymerization are mixed and dispersed in a 1 to 40% by weight aqueous latex solution, a water-soluble inorganic salt is added to the solution, and a coating layer of microparticles is formed on the surface of the core particles. 1. A method for producing a toner for developing an electrostatic image, the method comprising: forming a toner for developing an electrostatic image. 3. Mix and disperse the core particles formed by polymerization in a 1 to 40% by weight aqueous latex solution, and adjust the pH of the solution.
A method for producing a toner for developing an electrostatic image, characterized in that a coating layer of fine particles is formed on the surface of the core particles by changing the toner.