JP2000338723A - Positively chargeable toner and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the spherical toner good in positive charge-ability and its manufacturing method. SOLUTION: The positively chargeable spherical toner superior in stability with time and charge distribution is obtained by mixing an aqueous dispersion medium of (A) resin grains (I) composed essentially of a binder resin and a colorant, and with an aqueous dispersion medium (B) of fine resin particles (II) having basic groups containing a separately prepared carbon black as an essential component, and depositing the fine particles (II) on the surface of the resin grains (I) and stirring and mixing them after drying to stabilize and uniformize the surface of the toner particles, and finally adding the negatively chargeable inorganic fine particles to the outside of the toner particles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positively chargeable toner for developing an electrostatic image used in an electrophotographic copying machine or a printer, and a method for producing the same.

[0002]

2. Description of the Related Art As a method for producing a positively chargeable toner for developing an electrostatic image, a so-called pulverization method in which a colorant, a charge control agent, a wax, etc. is added to a binder resin, melt-kneaded, and pulverized and classified is conventionally used. Is being done. On the other hand, it is necessary to reduce the particle size of toner in order to achieve the recent demand for improvement in image quality for copiers and printers from the toner side. However, the pulverization method reduces the particle size in terms of productivity and performance. There are restrictions. That is, to produce a toner having a small particle size by a pulverization method, an increase in energy cost and a decrease in the yield occur, and with the reduction in the particle size, the powder fluidity decreases and the chargeability control becomes difficult. A problem in physical properties arises.

[0003] In view of such circumstances, a wet process for producing a positively chargeable toner has been studied. For example, a polymerizable monomer in which a colorant, a charge control agent, a wax and the like are dispersed is polymerized in a liquid medium to form toner particles. The so-called polymerization method for producing
JP-A-265247 discloses a method in which a tertiary amino group-containing resin is used as a binder resin component, the hydrophilicity is increased by neutralizing the resin, and the emulsion is phase-inverted and emulsified in an aqueous medium. A so-called phase inversion emulsification method for producing particles is known. In such a wet production method, there is no problem in producing toner particles having a small particle size. However, in the polymerization method, most of the added charge control agent is included in the toner particles, and a part of the added charge control agent is present on the particle surface. There is a problem that it is difficult to obtain a stable chargeability because the charge control agent is exposed non-uniformly.In addition, in the phase inversion emulsification method, the positive chargeability of the toner is ensured, but the toner is contained in a large amount. There is a problem that generation of odor due to the amino group is inevitable.

[0004]

Problems to be Solved by the Invention
27, in order to solve such a problem, a basic group-containing resin containing a small amount of a positively chargeable charge control agent is uniformly fixed on the surface of resin particles containing a colorant and a binder resin as essential components. And a method for producing the same are disclosed. However, the toner thus obtained does not always have a sufficiently satisfactory level of charging startability and charging stability over time.

SUMMARY OF THE INVENTION The present invention provides a positively chargeable toner having a small particle size, which is excellent in charge rising property and charge stability over time, and is excellent in image quality such as super-resolution and gradation. With the goal.

[0006]

Means for Solving the Problems Accordingly, the present inventors have:
Focusing on the problem to be solved by the invention as described above, as a result of intensive studies, as a toner particle structure,
On the surface of resin particles containing a colorant and a binder resin as essential components,
It has been found that a positively chargeable toner in which negatively chargeable inorganic fine particles are externally added to toner particles to which a basic group-containing resin containing carbon black as an essential component is fixed solves the above-mentioned problem.

In particular, a basic group-containing resin containing carbon black as an essential component (carbon black or carbon black and a positively chargeable charge control agent) is fixed to the surface of the negatively chargeable resin particles obtained by the phase inversion emulsification method. It has been found that a toner obtained by externally adding negatively chargeable inorganic fine particles to the obtained toner particles becomes a positively chargeable toner having excellent charging characteristics.

As one example of a method for obtaining a positively chargeable toner having such a particle structure, an aqueous dispersion (A) of resin particles (I) containing a colorant and a binder resin as essential components is neutralized. Self-water dispersible / or obtained by subjecting a mixture containing a basic group-containing resin that becomes water-soluble and carbon black to phase inversion emulsification, the particle size is smaller than the resin particles (I),
An aqueous dispersion (B) of fine particles (II) is added, and a resin having a basic group-containing resin containing carbon black as an essential component is fixed to the surface of the resin particles (I). The inventors found that the method of externally adding inorganic fine particles was effective, and completed the present invention.

That is, the present invention provides the following invention. Negatively chargeable inorganic fine particles are externally added to toner particles in which a basic group-containing resin containing carbon black as an essential component is fixed on the surface of resin particles (I) containing a colorant and a binder resin as essential components. Positively charged toner (hereinafter referred to as a first invention).

An aqueous dispersion (A) of resin particles (I) containing a colorant and a binder resin as essential components, a basic group-containing resin which becomes self-water dispersible and / or water-soluble by neutralization, and carbon black. An aqueous dispersion (B) of fine particles (II) having an average particle diameter smaller than that of the resin particles (I) and obtained by mixing the essential mixture with an aqueous medium in the presence of a neutralizing agent and phase-inverting and emulsifying the mixture.
Are uniformly mixed to precipitate fine particles (II) on the surface of the resin particles (I) with a neutralizing agent having a polarity opposite to that of the neutralizing agent, and then the liquid medium is removed and dried. A method for producing a positively chargeable toner in which a basic group-containing resin containing carbon black as an essential component is fixed on the surface (hereinafter, referred to as a second invention).

The second invention is preferably performed by the following method. That is, a mixture containing an acidic group-containing resin that becomes self-water dispersible by neutralization and a coloring agent as essential components, in the presence of a basic neutralizing agent, obtained by phase inversion emulsification in an aqueous medium, A method for producing a positively chargeable toner, comprising using spherical resin particles (I) containing an agent (hereinafter, referred to as a third invention).

Alternatively, spherical resin particles (I) containing a colorant obtained by polymerizing a polymerizable monomer in which a colorant is dispersed in a liquid medium and a binder resin as essential components are used. A method for producing a positively chargeable toner (hereinafter, referred to as a fourth invention).

The toner of the first invention has, for example, the following features in its particle structure. 1. Carbon black, or carbon black and a positively chargeable charge control agent, are uniformly finely dispersed in a basic group-containing resin. 2. Carbon black or a basic group-containing resin containing carbon black and a positively chargeable charge control agent is fixed to the surface of the resin particles (I) in the form of submicron particles. 3. The basic group of the basic group-containing resin is preferably a tertiary amino group. 4. The resin particles (I) preferably contain an acidic group, and more preferably, the acidic group is a carboxyl group. 5. Although the shape of the resin particles (I) is not limited, it is preferable that the practical sphericity of Wardell (the ratio of the diameter of a circle having an area equal to the projected area of the particle to the diameter of the smallest circle circumscribing the projected image of the particle) be satisfied. It is a spherical shape of 0.95 to 1.00. 6. Negatively charged inorganic fine particles are externally added to the surface of the toner particles. Preferably, the externally added inorganic fine particles are silica.

By having the above structural features, the following effects are exhibited. 1. Since carbon black is finely dispersed in the basic group-containing resin, appropriate conductivity is imparted to the surface of the toner particles, the charge level is reduced, and the charge rising property and uniform chargeability of the toner are improved. . 2. The practical sphericity of Wader of the resin particles (I) is 0.9
In the case of spherical particles having a particle size of 5 or more, since the surface treatment is performed uniformly, the uniform chargeability of the individual toner particles is further achieved. 3. When the resin particles (I) have an acidic group, preferably a carboxyl group, the fine particles (II) of the carbon black-containing basic group-containing resin are more strongly stiffened by the acid-base interaction. I) It adheres to the surface, and the deterioration of the developing characteristics due to peeling is reduced. 4. The external stability of the negatively charged inorganic fine particles improves the stability over time of charging.

In order to obtain the toner of the first invention described above, various manufacturing methods are conceivable.
The manufacturing method of the second invention is mentioned.

In the second invention, the aqueous dispersion (A) of the resin particles (I) for fixing the fine particles (II) of the basic group-containing resin containing carbon black as an essential component is obtained by any production method. But can be used. For example, an aqueous dispersion of resin particles obtained by dispersing resin particles obtained by a pulverization method in an aqueous medium containing a dispersion stabilizer, or resin particles obtained by a wet method such as a phase inversion emulsification method or a polymerization method Can be used.

In the third aspect of the present invention, a mixture containing an acidic group-containing resin which becomes self-water dispersible by neutralization and a colorant as essential components is mixed with an aqueous medium in the presence of a neutralizing agent, followed by phase inversion emulsification. An aqueous dispersion (A) of the resin particles (I) obtained by the above method is used. The resin particles (I) obtained by the present phase inversion emulsification method have a practical sphericity of 0.95 or more by Wardel and can form particles without using a dispersion stabilizer. The particles have little influence on the charging characteristics and are most suitable for the present invention.

As the resin particles (I), spherical colored resin particles obtained by a method of performing phase inversion emulsification using a dispersion stabilizer can be used. In this case, the particles are sufficiently washed. From the viewpoint of the environmental stability of the toner.

In the fourth invention, an aqueous dispersion of spherical resin particles (I) obtained by polymerizing a mixture containing a colorant, a polymerizable monomer and a polymerization catalyst thereof as essential components in a liquid medium is used. It is characterized by. In the production of the resin particles (I) by this method, although there are restrictions on the type of resin,
Although the polymerization reaction and spheroidization are performed simultaneously and the productivity is excellent, since a dispersion stabilizer is used for the polymerization reaction in the liquid medium,
Before adding the aqueous dispersion of the fine particles (II), it is necessary to sufficiently wash the resin particles (I).

Further, the second invention provides an aqueous dispersion (A) of resin particles (I) containing a colorant and a binder resin as essential components.
And a separately prepared mixture of a basic group-containing resin and carbon black, which are self-water dispersible / or water-soluble by neutralization, and carbon black as essential components, are mixed with an aqueous medium in the presence of an acidic neutralizing agent, and phase inversion is performed. Aqueous dispersion (B) of fine particles (II), obtained by emulsification, in which carbon black or carbon black and a positively chargeable charge controlling agent are uniformly finely dispersed, and have an average particle diameter smaller than that of resin particles (I). And are mixed uniformly,
This is a production method in which a basic neutralizing agent is deposited on the surface of the resin particles (I), and a positively chargeable toner having the features of the first invention can be easily produced.

Before describing the steps of the present invention, each component used in the present invention will be described. The binder resin that can be used for the resin particles (I) of the present invention may be any resin as long as it can be used as a toner binder resin, but the balance between powder fluidity and fixability as a toner is relatively easy. A styrene acrylic resin or a polyester resin which is easily obtained is particularly preferable.

The basic group-containing resin which can be used in the fine particles (II) of the present invention and becomes self-water dispersible and / or water-soluble by neutralization is not particularly limited. Resins are preferred.

In the present invention, the resin capable of becoming self-water dispersible by neutralization is defined as an emulsifier or a dispersant under the action of an aqueous medium by the action of a functional group in the molecule which can increase hydrophilicity by neutralization. It is a resin capable of forming a stable aqueous dispersion or aqueous solution without substantially using a stabilizer. If a resin that can become self-water dispersible by neutralization (a resin having an acidic or basic functional group in its molecular chain that can increase hydrophilicity by neutralization) has an acidic group, Is neutralized with an acid if it has a basic group, thereby making the functional group into a salt structure and increasing the hydrophilicity.

The degree of hydrophilicity can be appropriately adjusted by the degree of neutralization (neutralization rate). The degree of hydrophilicity at this time must be such that the resin itself can be dispersed in water. When such a self-water-dispersible resin is mixed with an aqueous medium, phase inversion emulsification occurs to form particles.

The hydrophilicity of a resin containing an acid group or a basic group and capable of becoming self-water dispersible by neutralization is determined by the amount of a functional group or the amount of neutralization (neutralization rate) that can increase the hydrophilicity by neutralization. Can be controlled by A self-water-dispersible resin can be obtained by using a resin that becomes water-soluble when neutralized to a certain degree of neutralization or higher and reducing the degree of neutralization.

In the production method of the present invention, the basic group-containing resin is
It is preferable to use a resin that can be made water-soluble when neutralized to a certain neutralization rate or more.

Further, the particle size at the time of dispersion in phase inversion emulsification is determined by such hydrophilicity. That is, an arbitrary particle size can be easily obtained by controlling the neutralization ratio.

Examples of the functional group of the resin which can increase hydrophilicity by neutralization in the resin include, for example, a carboxyl group, a phosphoric acid group, a sulfone group and a sulfate group as the acidic group. preferable. Also,
Examples of the basic group include a primary, secondary, tertiary amino group, and quaternary ammonium group, and among them, a tertiary amino group is preferable. The appropriate neutralization ratio for the resin to exhibit self-water dispersibility or water solubility differs for each resin because the hydrophilicity of the resin itself varies depending on the monomer composition, molecular weight, and the like.

As the resin which can become self-water dispersible or water-soluble by neutralization, a styrene acrylic resin or a polyester resin, which can easily obtain a balance between powder fluidity and fixability as a toner, is preferable. is there.

The neutralization can be self-water dispersible.
As the acid group-containing styrene acrylic resin, a radical polymerizable monomer containing an acid group, and a radical polymerizable monomer other than the acid group-containing radical polymerizable monomer, a polymerization initiator is used. Below, what is obtained by radical polymerization can be used.

The basic group-containing resin which can be made self-water dispersible and / or water-soluble by the neutralization includes a polymerizable monomer containing a basic group and a polymerizable monomer containing the basic group. Those obtained by subjecting a polymerizable monomer other than the monomer to radical polymerization in the presence of a radical initiator can be used. The polymerization reaction for obtaining these can be suitably used in solution polymerization, suspension and emulsion polymerization.

Examples of such acidic group-containing polymerizable monomers include acrylic acid, methacrylic acid, crotonic acid,
Examples include itaconic acid, maleic acid, fumaric acid, monobutyl itaconate, monobutyl maleate and the like. Also,
Examples of the basic group-containing polymerizable monomers include acrylate derivatives such as dimethylaminoethyl, diethylaminoethyl, dibutylaminoethyl, and N-ethyl-N-phenylaminoethyl, and methacrylate derivatives.
Also, N-vinyl pyrrole, N-vinyl carbazole,
N- such as N-vinylindole and N-vinylpyrrolidone
Vinyl compounds are also included.

Examples of the polymerizable monomers other than the acidic or basic group-containing polymerizable monomers include: (1) Styrene-based monomers: styrene, vinyltoluene, 2-methylstyrene, t-butylstyrene Or chlorostyrene (2) acrylates: methyl acrylate, ethyl acrylate, isopropyl acrylate, n-acrylate
-Butyl, isobutyl acrylate, n-amyl acrylate, isoamyl acrylate, n-hexyl acrylate,
2-ethylhexyl acrylate, n-octyl acrylate, decyl acrylate or dodecyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl alpha-chloroacrylate (3) Methacrylate: methyl methacrylate, propyl methacrylate, N-butyl methacrylate, isobutyl methacrylate, n-amyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate,
N-octyl methacrylate, decyl methacrylate, dodecyl methacrylate, 2-chloroethyl methacrylate, phenyl methacrylate, methyl methacrylate alpha (4) acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, acrylamide; Vinyl ether: vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, (6) vinyl ketone: vinyl methyl ketone, vinyl hexyl ketone, methyl isopropenyl ketone (7) N-vinyl compound: N-vinyl pyrrole, N-vinyl carbazole, N -Vinylindole, N-vinylpyrrolidone and the like.

In the case of obtaining the resin, a general-purpose organic solvent can be used in the case of solution polymerization. Examples of the organic solvent used include various hydrocarbons such as toluene, xylene, benzene, n-hexane, cyclohexane and n-heptane; methanol, ethanol, isopropanol, n-propanol, n-butanol, isobutanol, sec- Alcohols such as butanol and t-butanol; propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monoisopropyl ether, propylene glycol mono n-butyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether; Ether alcohols such as ethylene glycol mono n-butyl ether; acetone, methyl ethyl ketone, Various ketones such as butyl isobutyl ketone; various esters such as ethyl acetate, butyl acetate and isobutyl acetate; various ether esters such as propylene glycol monoethyl ether acetate and ethylene glycol monoethyl ether acetate; various cyclic ethers such as tetrahydrofuran Various organic solvents such as various halogenated hydrocarbons such as methylene chloride;

As the polymerization initiator to be used, various known and used organic peroxide initiators and azo initiators can be used. Specifically, for example, peroxides such as benzoyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, sodium persulfate and ammonium persulfate, and azo-based compounds such as azobisisobutyronitrile and azobisisovaleronitrile Compounds.

The acid group-containing styrene acrylic resin used for the binder resin of the resin particles (I) of the present invention has an acid value of 3
0 to 150 (mgKOH / g), weight average molecular weight 600
Those having a composition such as 0 to 300,000 and a glass transition temperature of 45 to 70 ° C. are suitable.

The basic group-containing styrene acrylic resin used in the fine particles (II) of the present invention includes an amine value of 20 to 1
00 (mg HCl / g), weight average molecular weight 2000-4
00000, preferably 6000 to 300,000, and a glass transition temperature of 30 to 120 ° C. are preferable.

As another resin having an acidic group to be used as the binder resin of the resin particles (I) of the present invention, a polyester resin can be used, and a known and commonly used polyester resin for toner can be used. Such a polyester resin can be produced by subjecting a polybasic acid and a polyhydric alcohol to dehydration polycondensation in the presence of a catalyst. A portion of the polybasic acid may be subjected to demethanol polycondensation using its methyl esterified product, which is one of its ester-forming derivatives.

Examples of polybasic acids include terephthalic acid,
Aromatic carboxylic acids such as isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, naphthalenedicarboxylic acid, maleic anhydride, fumaric acid, succinic acid,
Examples include aliphatic carboxylic acids such as alkenyl succinic anhydride and adipic acid, and alicyclic carboxylic acids such as cyclohexanedicarboxylic acid. One or more of these polybasic acids can be used.

Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, butanediol,
Hexanediol, neopentyl glycol, aliphatic diols such as glycerin, cyclohexanediol,
Examples include alicyclic diols such as cyclohexanedimethanol and hydrogenated bisphenol A, aromatic diols such as ethylene oxide adduct of bisphenol A and propylene oxide adduct of bisphenol A. One or more of these polyhydric alcohols can be used.

The glass transition temperature of the polyester resin is 50
７５75 ° C., more preferably 55-7 ° C.
0 ° C. If the glass transition temperature is less than 50 ° C., the heat-resistant aggregation property of the toner becomes poor, and if it exceeds 75 ° C., the fixability becomes poor, which is not preferable.

The content of the acid group in the polyester resin is determined by the mixing ratio of the polybasic acid and the polyhydric alcohol and the reaction rate.
It can be adjusted by controlling the terminal carboxyl group of the polyester. Alternatively, a polyester having a carboxyl group in the main chain can be obtained by using trimellitic anhydride as the polybasic acid component. The content of the acid group of the polyester resin is 1 as an acid value.
３０30 mg · KOH / g is preferred.

The neutralizing agent used in the present invention must be properly used as follows. To convert the acidic group-containing resin to self-water dispersibility, a basic neutralizer is used. To convert the basic group-containing resin to self-water dispersibility / or water solubility, a basic neutralizer is used. A wetting agent is used. Further, an acidic neutralizing agent is used in order to return the acidic group-containing resin, which has become a salt structure by neutralization, to the original acidic group. In addition, a basic neutralizing agent is used in order to return the basic group-containing resin, which has become a salt structure by neutralization, to the original basic group and precipitate the resin on the surface of the resin particles.

Examples of the basic neutralizer include inorganic metals such as sodium hydroxide, potassium hydroxide and lithium hydroxide; inorganic alkalis such as ammonia; alkanolamines such as monoethanolamine and diethanolamine; dimethylamine; Secondary amines such as diethylamine, tertiary amines such as triethylamine, and organic amines such as hydrazine.Examples of the acidic neutralizing agent include inorganic acids such as hydrochloric acid, sulfuric acid, and phosphoric acid, oxalic acid, formic acid, and acetic acid. And organic acids such as succinic acid and p-toluenesulfonic acid.

When a water-insoluble resin which does not disperse in water by itself, ie, does not have self-water dispersibility, is used as the water-insoluble resin as the binder resin of the resin particles (I), the resin solution and / or Or an aqueous medium mixed therewith (the aqueous medium is
It is necessary to add an emulsifier and / or a dispersion stabilizer to water or a liquid medium containing water as a main component).

As the dispersion stabilizer, a water-soluble polymer compound is preferable, and examples thereof include polyvinyl alcohol, polyvinyl pyrrolidone, hydroxyethyl cellulose, carboxymethyl cellulose and the like. Examples of the emulsifier include various nonionic surfactants such as polyoxyethylene alkylphenol ether, and various anionic or cationic surfactants such as sodium alkylbenzenesulfonate. Of course, two or more kinds of emulsifiers may be used in combination, two or more kinds of dispersion stabilizers may be used in combination, or an emulsifier and a dispersion stabilizer may be used in combination. It is common to use an emulsifier in combination.

In this case, when an emulsifier or a dispersion stabilizer is used, its concentration in the aqueous medium is suitably adjusted to about 0.5 to 3% by weight.

Further, even when a resin which can be made self-water dispersible by neutralization as described above is used, if necessary, the emulsifier and / or dispersion stability may be used as long as the effects of the present invention are not impaired. Agents may be used.

In order to form spherical colored particles for toner and the like by emulsification, a method without using an organic solvent as described in US Pat. No. 5,843,614 may be used. Can be used as (I).

Next, the resin particles (I) used in the present invention
Will be described with respect to a so-called polymerization method in which a polymerizable monomer in which a colorant is dispersed is polymerized in a liquid medium to form a polymer.

For example, a colorant and a polymerizable monomer capable of forming a binder resin are suspended or emulsified in a liquid medium in the presence of a dispersion stabilizer or an emulsifier, and a polymerization initiator is used. A polymerization reaction by radical polymerization is carried out with stirring in the presence of a toner to obtain a spherical aqueous dispersion of toner particles containing a colorant in a binder resin.

Specific examples of the radical polymerizable monomer include styrenes such as styrene, α-methylstyrene, chlorostyrene and vinylstyrene, monoolefins such as ethylene, propylene, butylene and isobutylene, and vinyl acetate. , Vinyl esters such as propion vinyl, vinyl butyrate, vinyl benzoate, methyl acrylate,
Α-methylene aliphatic monocarboxylic esters such as ethyl acrylate, butyl acrylate, octyl acrylate, phenyl dodecyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate and dodecyl methacrylate; ethylene glycol monoacrylate , Glycol mono (meth) acrylates such as propylene glycol monoacrylate, tetramethylene ether glycol monoacrylate, vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl butyl ether, vinyl methyl ketone, vinyl hexyl ketone, vinyl propenyl ketone, etc. And acrylic monomers such as vinyl ketones, and these can be used alone or in combination of two or more.

The monomer composition constituting the binder resin is prepared such that the glass transition temperature of the polymer is 50 to 80 ° C.

If necessary, a small amount of a reactive monomer having two or more ethylenically unsaturated double bonds may be used in combination therewith. Examples of the reactive monomer having two or more ethylenically unsaturated double bonds include conjugated dienes such as butadiene and isoprene, divinylbenzene, di (meth) acrylate of bisphenol A alkylene oxide adduct, and trimethylolpropanetri (meta). A) acrylate, pentaerythritol tetra (meth) acrylate, and the like.

As the polymerization initiator used for obtaining such a polymer resin, of course, ordinary oil-soluble or water-soluble ones can be used. For example, benzoyl peroxide,
Various peroxides, such as di-t-butyl peroxide, cumene hydroperoxide, t-butyl peroxide or 2-ethylhexanoate; or various azos, such as azobisisobutyronitrile or azobisisovaleronitrile. Compounds and the like can be mentioned.

In the case of suspension polymerization, a polymerization initiator which is insoluble in the liquid medium used for the polymerization and which is soluble in the monomer is selected and used as an essential component. In the case of emulsion polymerization, a water-soluble polymerization initiator is selected and used as an essential component. used. The amount of the polymerization initiator used is not particularly limited, but is 0.01 to 5 parts by weight per 100 parts by weight of the total polymerizable monomer.

The binder resin formed by the polymerization can be arbitrarily prepared depending on the polymerization conditions and the like, but is preferably adjusted to have a weight average molecular weight of 10,000 to 500,000.

As the dispersion stabilizer that can be used during suspension polymerization, a water-soluble polymer compound is generally used, and examples thereof include polyvinyl alcohol, polyvinyl pyrrolidone, hydroxyethyl cellulose, carboxymethyl cellulose, cellulose gum, and ramzan gum. No.

Further, it is insoluble in water and has a particle size of 0.01 to 5 μm.
m inorganic fine powder can also be used as a suspension dispersion stabilizer, for example, tricalcium phosphate, talc, bentonite, kaolin, titanium oxide, alumina, zinc white, aluminum hydroxide, magnesium hydroxide, basic magnesium silicate, Examples include titanium hydroxide, ferric hydroxide, barium sulfate, silica, magnesium carbonate, calcium carbonate, and the like.

These dispersion stabilizers may be used alone or in combination of two or more. The amount used is usually 0.1 to 10 parts by weight per 100 parts by weight of all reactive monomers.

Examples of the emulsifier which can be used in the emulsion polymerization include anionic surfactants such as sodium dodecylbenzenesulfonate, sodium lauryl sulfate, sodium dodecyldiphenyloxide disulfonate, polyoxyethylene lauryl ether, and polyoxyethylene ninyl phenol ether. And the like. These may be used alone or in combination of two or more. The amount used is usually 0.01 to 5 parts by weight per 100 parts by weight of the total reactive monomers.

In suspension polymerization, an emulsifier may be used in combination with a dispersion stabilizer, or in emulsion polymerization, a dispersion stabilizer may be used in part with an emulsifier. Further, a self-emulsifiable epoxy resin or a self-emulsifiable polyurethane resin can be used in place of the dispersion stabilizer or the emulsifier.

A polymerizable monomer, a colorant, a dispersion stabilizer, a liquid medium insoluble in the monomer, and a polymerization initiator insoluble in the liquid medium and soluble in the monomer are simultaneously added and stirred. Although monomer droplets may be polymerized, a polymerizable monomer and a colorant may be used.
For example, in a ball mill or a colloid mill, etc., previously sufficiently mixed, then added to the polymerization medium, the liquid medium containing a dispersion stabilizer, for example, a homogenizer, a rotor-stator mixer, static stirring, etc., It is preferable that monomer droplets containing a polymerizable monomer be suspended in a liquid medium and polymerization is performed while stirring is continued until toner particles having a predetermined particle size are formed.

Examples of the liquid medium that can be used in carrying out such polymerization include water such as distilled water and ion-exchanged water,
Various aromatic hydrocarbons such as toluene, xylene or benzene; various alcohols such as methanol, ethanol, propanol or butanol; various ether alcohols such as cellosolve or carbitol; acetone, methyl ethyl ketone or methyl isobutyl Examples include various ketones such as ketones; various esters such as ethyl acetate or butyl acetate; and various ether esters such as butyl cellosolve acetate.

In each of the polymerization methods, the core
By employing a shell polymerization formulation, a power feed polymerization formulation, or a graft polymerization formulation, the chemical structure and layer structure of the particles can be varied. The reaction conditions in each of the suspension polymerization method and the emulsion polymerization method of the above inventions are not particularly limited, and in each case, the reaction temperature is usually from room temperature to 80 ° C. for 15 minutes to 24 hours.

As the coloring agent in the present invention, carbon black is most preferably used, but other known and commonly used coloring agents for toner can also be used. For example, magnetic powder, aniline blue, calcoil blue, chrome yellow, ultramarine blue, Dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, rose bengala, C.I. I. Pigment Red 12
2, C.I. I. Pigment Yellow 97, C.I. I. Pigment Blue 15, iron tetroxide, iron sesquioxide, iron powder, zinc oxide, selenium, etc., and can be used alone or in combination of two or more.

The amount of the colorant used is usually 100
It is selected from the range of 3 to 15 parts by weight per part by weight.

The carbon black dispersed in the basic group-containing resin and used for fixing to the surface of the resin particles (I) is not particularly limited, and carbon black for commercially available black pigments or conductive carbon black may be used. Is preferred. In the present invention, it is preferable that the carbon black is dispersed as finely as possible in the basic group-containing resin solution.

The amount of the basic group-containing resin containing carbon black added to the surface of the resin particles (I) is 0.05 to 5% by weight based on the solid content of the resin particles.
Preferably, the content of the basic group-containing resin is 0.1 to 2% by weight.
The range of 1 to 10% by weight, preferably 0.1 to 3% by weight is suitable. In the case of a basic group-containing resin containing carbon black and a positive charge control agent, the positive charge control agent is contained in an amount of 0.01 to 5% by weight, preferably 0.01 to 2% by weight, based on the resin particles (I). % By weight, 0.1 to 5 carbon black
%, Preferably 0.1 to 2% by weight, and the basic group-containing resin is 0.1 to 10% by weight, preferably 0.1 to 3% by weight.
The following range is preferable. If the amounts of the charge control agent and the basic group-containing resin are too large beyond these ranges, the charge amount becomes too high and the stability over time of charging is undesirably reduced. On the other hand, if the amount of carbon black added exceeds the above range and is too large, the charge amount is undesirably too low. Appropriate amounts of these components vary depending on the resin characteristics of the resin particles (I), the characteristics of the external additives, the characteristics of the carrier, and the like, and are appropriately determined according to the case.

In the present invention, the organic solvent used for producing the resin particles (I) or the fine particles (II) by phase inversion emulsification includes:
Any organic solvent may be used as long as it dissolves the resin used. Further, the organic solvent used in the resin synthesis may be used as it is. As described above, for example, toluene,
Aromatic hydrocarbon solvents such as xylene and benzene, ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, ether solvents such as tetrahydrofuran, and halogen solvents such as carbon tetrachloride, trichloromethane and dichloromethane are used. In this case, for example, the combined use of a water-soluble or partially water-soluble organic solvent such as acetone, butanol, or isopropyl alcohol facilitates the generation of particles in phase inversion emulsification.

Preferably, the use of so-called low-boiling solvents, such as acetone, methyl ethyl ketone or ethyl acetate, tetrahydrofuran, which can be easily removed, is suitable.

Other constituents (additive components) of the resin particles (I) include various auxiliaries such as a release agent, and may be appropriately selected according to the purpose and conditions of use. Can be used. For example, polyethylene wax, polypropylene wax, waxes such as paraffin wax, metal soap, lubricants such as zinc stearate, etc., among them, among others, aqueous dispersion of synthetic wax synthesized by Fischer-Tropsch method, or emuljo type These can be added to the resin solution before phase inversion emulsification, and after phase inversion emulsification, can be included in the particles.

Next, the steps of the production method of the present invention will be described. The present invention can be roughly divided into four steps. That is, a step (1) of obtaining an aqueous dispersion (A) of resin particles (I) containing a colorant and a binder resin as essential components;
Step (2) of separately preparing an aqueous dispersion (B) of fine particles (II) of a basic group-containing resin containing carbon black as an essential component, and (A) and (B) are uniformly mixed.
Step (3) of depositing fine particles (II) of a basic group-containing resin containing carbon black as an essential component on the surface of the resin particles (I), and then removing the liquid medium and drying to obtain a toner powder Step (4). Of course, the steps (1) and (2) may be performed first or simultaneously. The description will be given for each process.

Step (1) is a step of obtaining an aqueous dispersion (A) of resin particles (I) containing a binder resin and a colorant as essential components.

The resin particles (I) may be obtained by any method as described above. In some cases, a dispersion stabilizer or the like can be used to disperse the particles in an aqueous medium. In particular, when a particle obtained as an aqueous dispersion by a wet method such as a polymerization method or a phase inversion emulsification method is used, it is preferable in that the step of dispersing the particles in an aqueous medium can be omitted.

Particularly, a mixture containing an acidic group-containing resin which becomes self-water dispersible by neutralization without using a dispersion stabilizer or an emulsifier, and a coloring agent as an essential component is mixed with an aqueous medium in the presence of a neutralizing agent. In the present invention, a method using an aqueous dispersion containing spherical resin particles (I) containing a colorant, which is obtained by mixing and phase-inversion emulsification with the above, is most preferred. Next, a spherical resin particle (I) containing a colorant, obtained by a polymerization method or a phase inversion emulsification method, which is carried out in combination with a dispersion stabilizer, an emulsifier, and the like.
In the present invention, a method using an aqueous dispersion containing

In the case of using the resin particles (I) by a phase inversion emulsification method which does not use a dispersion stabilizer or an emulsifier, the acidic group-containing resin which can become self-water dispersible by neutralization is neutralized with a neutralizing agent. The resulting acidic group-containing resin having a salt structure, and a colorant, as essential components, if necessary, a mixture containing an organic solvent that dissolves the resin is mixed with an aqueous medium to obtain a phase inversion emulsification. Resin particles (I) containing a colorant, and partially having a salt structure and containing an acidic group-containing resin
(A) is obtained.

In this case, first, for example, an acidic group-containing resin in which a part of the acidic group has a salt structure with a neutralizing agent, a coloring agent, and, if necessary, an organic solvent are mixed with a known and commonly used compound. A mixture is prepared by mixing and dispersing by means. For example, known and commonly used means such as a ball mill, a sand mill, and a motor mill can be employed.

As the organic solvent used for preparing the mixture, any of the above-mentioned ones can be used. When the resin is subjected to solution polymerization, the same organic solvent as that used at that time can be used. As described above, the types of the organic solvent used for the solution polymerization and the organic solvent used for preparing the mixture may be changed and used.

In preparing the mixture, by including a water-soluble or partially water-soluble organic solvent such as acetone, butanol, isopropyl alcohol, etc., the production of the resin particles in this step is facilitated. The nonvolatile content in the mixture is usually adjusted within the range of 20 to 80% by weight.

In order to obtain an acidic group-containing resin in which a part of acidic groups has a salt structure with a neutralizing agent, an acid group-containing resin which can become self-water dispersible by neutralization is mixed with a neutralizing agent. You just have to add them.

It is also possible to prepare a mixture containing an acidic group-containing resin which can become self-water dispersible by neutralization and a coloring agent as essential components and, if necessary, an organic solvent.

In this case, as the aqueous medium used for the phase inversion emulsification, an aqueous medium containing an amount of a neutralizing agent necessary to make the acidic group-containing resin self-water dispersible, or just before the phase inversion, Neutralization is performed at any stage up to. Preferably, the neutralizing agent is added just before the aqueous medium is added.

In any case, the mixture is mixed with the corresponding aqueous medium and subjected to phase inversion emulsification to obtain a dispersion of resin particles (I) containing a colorant. In this case, phase inversion emulsification may be performed by adding the corresponding aqueous medium to the mixture, or phase inversion emulsification may be performed by adding the mixture to the corresponding aqueous medium.

In the step (1), the average particle size is usually 3 to 1
An aqueous dispersion containing 2 μm of resin particles (I) is obtained.

The above-mentioned resin particles (I) may be obtained by removing the organic solvent from the aqueous dispersion after the phase inversion emulsification. Further, in the production method of the present invention, the resin particles (I) are obtained by removing the organic solvent from the aqueous dispersion after the phase inversion emulsification, and separating the aqueous medium by filtration.
After washing the wet cake, redispersed in an aqueous medium,
It is preferable that the salt portion contained in the acidic group-containing resin is returned to the original acidic group with an aqueous hydrochloric acid solution.

As a result, acidic groups are exposed on the surface of the resin particles, and fine particles of a basic group-containing resin containing carbon black as an essential component (I)
It is firmly fixed by the acid-base interaction with I).

In the step (2), a mixture containing a basic group-containing resin which becomes self-water dispersible by neutralization and carbon black as essential components is mixed with an aqueous medium in the presence of a neutralizing agent to carry out phase inversion emulsification. Aqueous dispersion liquid (B) of fine particles (II) having a mean particle diameter smaller than that of resin particles (I), wherein carbon black or the like is dispersed and encapsulated or adsorbed to 1 μm or less,
This is the step of obtaining One important point here is to sufficiently finely disperse carbon black and the like.

The basic group-containing resin having a salt structure formed by a neutralizing agent and the organic solvent for dissolving the resin used herein include the above-mentioned alcohol-based solvents, ketone-based solvents, and ether-based solvents. Any organic solvent may be used as long as it is selected from among them. Among them, tetrahydrofuran is preferably used for the purpose of the present invention.
In this case, they may be used alone or as a mixed solvent.

The fine particles (II) in the aqueous dispersion (B) can be obtained by the same operation as in the resin particles (I) in the step (1). The average particle diameter of the fine particles (II) needs to be smaller than that of the resin particles (I), and is 0.1 to 2 μm, particularly preferably 0.1 to 1 μm.

It is preferable to remove the organic solvent from the aqueous dispersion (B) after the phase inversion emulsification.

In the step (3), the aqueous dispersions (A) and (B) obtained in the steps (1) and (2) are uniformly mixed, and a part or all of the basic group is converted to a salt. In the step of adding a basic neutralizing agent to a basic group-containing resin that has been converted into a structure and has increased hydrophilicity, and returns to the original non-neutralized (unneutralized) basic group In some cases, such treatment reduces the hydrophilicity of the resin containing carbon black, and precipitates fine particles (II) on the surface of the resin particles (I). At this time, the fine particles (II) are firmly fixed to the surface of the resin particles (I).

In this case, if the deposition rate of the fine particles (II) is too high, the fine particles aggregate, and not only are not uniformly deposited on the surface of the resin particles (I), but also the resin particles (I) aggregate. This is not preferred.

In the production method of the present invention, a resin having a tertiary amino group as a basic group is used, the resin is neutralized with a strong acid, and then treated with ammonia, which is a weak base, to reduce the deposition rate. Slowly, the particles are hardly aggregated with each other, and can be uniformly fixed to the surface of the resin particles.

The amount of the fine particles (II) added to the resin particles (I) is 0.05 to 10% by weight, preferably 0.1 to 6% by weight, based on the solid content of the resin particles (I). Is preferred.

The precipitation step is generally performed under stirring. The stirring blade is not particularly limited, but a stirring blade such as a Faudler blade having a small air entrapment is preferable.

The basic neutralizing agent used for the precipitation is as follows:
It may be added until the solid content of the mixture of the dispersion liquid (A) and the dispersion liquid (B) is 20% by weight, the water temperature is 20 ° C., and the pH is 9 to 10. After adjusting the pH to a predetermined value, stirring is performed for about 30 minutes to completely fix the fine particles (II) on the surface of the resin particles (I).

In the step (4), the toner particles obtained in the step (3) and having a basic group-containing resin containing carbon black as an essential component fixed to the surface are separated from a liquid medium, dried, and dried. This is the step of obtaining toner.

The toner particles separated from the liquid medium are dried to obtain a toner powder. This drying can be performed by any known and commonly used method, for example, by heating and drying at a temperature at which the toner particles do not fuse or aggregate, or by freeze drying. There is also a method in which separation and drying of toner particles from an aqueous medium and drying are performed simultaneously using a continuous instantaneous air-flow dryer or a spray dryer.

After drying, the toner particles used in the present invention
It is preferable to stir and mix the powder using a known and commonly used stirring and mixing machine such as a Henschel mixer or a hybridizer to stabilize and homogenize the particle surface. In this case, it is more preferable to stir and mix while heating to a temperature range in which aggregation of the toner particles does not occur, because the stabilizing effect is promoted.

As the particle size of the toner particles used in the present invention, any size can be selected within a practical level as a toner. From the point of matching with the current machine, it is preferable that the volume average particle diameter is in the range of 3 to 15 μm. In particular, a small particle size toner having a volume average particle size of about 3 to 8 μm is preferable because it has excellent image quality such as resolution and gradation.

In general, inorganic fine particles are externally added to the toner particles obtained by the above method in order to secure appropriate fluidity and chargeability as an electrostatic image developer. Such inorganic fine particles include silica, titanium oxide, alumina,
Examples include barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, cerium oxide, antimony trioxide, zirconium oxide, silicon carbide, and silicon nitride.

The present inventors have found that among these inorganic fine particles, the use of negatively-chargeable inorganic fine particles, particularly, silica having a negatively-charged hydrophobized surface treatment, makes it possible to obtain positively-charged particles having excellent charging stability over time. It has been found that a hydrophilic toner can be obtained. Examples of the surface treatment agent for silica used in the present invention include various organic silicon compounds, fluorine-based organic compounds, titanate-based coupling agents, aluminum-based coupling agents, and fluoro (meth) acrylate (co) polymers. .
Among these, silica surface-treated with an organosilicon compound is practically suitable because it is easily available, and examples of such an organosilicon compound include various silicone oils and organochlorosilanes (trichloromethylsilane, dichloromethylsilane, Chlorodimethylsilane, chlorotrimethylsilane, trichloroethylsilane, dichlorodiethylsilane, chlorotriethylsilane, chlorotriphenylsilane, etc.), organosilazane (triethylsilazane, triphenylsilazane, hexaethyldisilazane, hexamethyldisilazane, etc.) and Organoalkoxysilanes (dimethoxydimethylsilane, trimethoxymethylsilane, etc.)
And the like.

The silica used in the present invention has a primary particle size of about 5 to 200 nanometers, particularly preferably 5 to 200 nanometers.
Commercially available silica having a size of about 50 nanometers and meeting such conditions includes AEROSIL R97.
2, R976, RX200, NAX50, RY200;
WACKER HDK H1018, H1303VP,
H2000 / 4, H2000, H3004, SLM50
650, H15, H20, H30; Nipsil SS
-10, SS-15, SS-20, SS-50, SS-60, SS-100, SS-40, SS-70 and the like.

The external addition amount of silica is based on the toner particles.
It is about 0.1 to 5% by weight, particularly preferably about 0.1 to 3% by weight.

In the positively chargeable toner of the present invention, the above-mentioned negatively chargeable silica may be externally added together with other inorganic fine particles or organic fine particles.

The toner obtained by the production method of the present invention can be used as a non-magnetic one-component toner or a magnetic one-component toner.
Also, by combining with a carrier, it can be used as a two-component developer, and a high quality image can be obtained by developing good charging characteristics.

As the carrier, any known and commonly used carriers can be used. For example, iron, nickel, copper, zinc, cobalt, manganese, chromium, rare earth and other metals and their alloys or oxides, surface-treated glass, powders of silica, etc. can be used, and their acrylic resin coated carriers,
Resin-coated carriers such as fluororesin-coated carriers, fluorine / acrylic resin-coated carriers, and silicone resin-coated carriers are more suitable for use in the positively chargeable toner of the present invention. The average particle size of the carrier is not particularly limited, but those having a size of about 20 to 200 microns are preferably used.

[0109]

BEST MODE FOR CARRYING OUT THE INVENTION Negatively-chargeable inorganic fine particles are externally added to toner particles in which a basic group-containing resin containing carbon black as an essential component is fixed on the surface of resin particles (I) containing a colorant and a binder resin as essential components. Positively charged toner. 2. 2. The toner according to the above item 1, wherein the inorganic fine particles are silica. 3. 2. The toner according to the above item 1, wherein the basic group is a tertiary amino group. 4. 2. The toner according to 1 above, wherein the toner particles have a spherical shape with a Wardel practical sphericity of 0.95 or more. 5. An aqueous dispersion (A) of resin particles (I) containing a colorant and a binder resin as essential components, a basic group-containing resin that becomes self-water dispersible and / or water-soluble by neutralization, and carbon An aqueous dispersion of fine particles (II) having an average particle diameter smaller than that of the resin particles (I), obtained by mixing a mixture essentially containing black with an aqueous medium in the presence of an acidic neutralizing agent and inverting the mixture by phase inversion. (B) is uniformly mixed, fine particles (II) are precipitated on the surfaces of the resin particles (I) with a basic neutralizing agent, and then the liquid medium is removed and dried. A method for producing the toner described in the above. 6. A mixture containing, as essential components, an acidic group-containing resin and a colorant, in which the resin particles (I) become self-water dispersible by neutralization, are mixed with an aqueous medium in the presence of a basic neutralizer, and phase-inverted and emulsified. 6. The production method according to the above item 5, wherein the obtained colorant is a spherical particle containing a colorant. 7. 6. The method for producing a toner according to the above item 5, wherein the resin particles (I) are spherical particles obtained by polymerizing a polymerizable monomer in which a colorant is dispersed in a liquid medium.

In an embodiment of the present invention, spherical particles produced by a wet method are used as resin particles (I), and fine particles (II) of a basic group-containing resin containing carbon black as an essential component are used as resin particles (I). The toner in which toner particles fixed to the surface of (I), the toner particles are dried, and negatively chargeable silica is externally added is most preferable in the present invention.

[0111]

Next, the present invention will be specifically described with reference to comparative examples and examples. In the following, all parts and percentages are by weight. All water means deionized water.

REFERENCE EXAMPLE 1 Synthesis Example of Styrene Acrylic Resin Having Carboxyl Group Methyl ethyl ketone / isopropyl alcohol / water was placed in a 3 liter flask equipped with a dropping device, a thermometer, a nitrogen gas inlet tube, a stirring device, and a reflux condenser. Of 114/12/24
After the parts were charged, the temperature was raised to 80 ° C., and the mixture comprising the monomers of Composition 1 and the polymerization initiator was batch-started to start the charging reaction.

Composition 1 330 parts of styrene 216 parts of butyl acrylate 54 parts of acrylic acid “Perbutyl O” (manufactured by NOF Corporation) 0.6 part

[0114] Then, every three hours after three hours, about 10 parts of the reaction resin solution was sampled, diluted with the same amount of methyl ethyl ketone, and the viscosity was measured with a Gardner viscometer. When the viscosity becomes PQ, methyl ethyl ketone /
567/63 parts of isopropyl alcohol were added, and after the temperature reached 80 ° C., a mixture having a ratio as shown in composition 2 was added dropwise over 1 hour. At this time, the polymerization rate of the first stage was calculated by quantifying the residual monomer ratio by gas chromatography and found to be 60%.

Composition 2 Styrene 413 parts Butyl acrylate 133 parts Acrylic acid 54 parts “Perbutyl O” 18 parts

After the completion of the dropwise addition, 2 parts of “perbutyl O” were added three times every three hours, and the reaction was continued for another four hours. Finally, the non-volatile content is 5 with methyl ethyl ketone.
It was adjusted to 0% to obtain a resin solution. This resin has an acid value (KOH required to neutralize 1 g of resin solids)
Mg, 70, weight average molecular weight 124,000, Tg6
1 ° C.

Reference Example 2 Synthesis Example of Styrene Acrylic Resin Having Tertiary Amino Group 670 parts of methyl ethyl ketone was placed in a 3-liter flask equipped with a dropping device, a thermometer, a nitrogen gas inlet tube, a stirrer, and a reflux condenser. , And the mixture was heated to 80 ° C., and a mixture comprising the following monomers and a polymerization initiator was added dropwise over 2 hours.

Styrene 732 parts Butyl acrylate 100 parts Dimethylaminoethyl methacrylate 168 parts “Perbutyl O” 8 parts

[0119] Then, three hours after the completion of the dropping, every three hours, four times each of the polymerization catalyst perbutyl O was added.
Parts were added. Next, after adding perbutyl O, the reaction was further continued for 4 hours, and the reaction was terminated. Finally, a resin solution was obtained by adjusting with methyl ethyl ketone so that the nonvolatile content became 50%. This resin had an amine value (mg of HCl required to neutralize 1 g of solid resin) of 39, a weight average molecular weight of 142,000, and a Tg of 68 ° C.

Reference Example 3 Production Example of Resin Particles (I) by Phase Inversion Emulsion 900 parts of the resin solution prepared in Reference Example 1 and ELFTEX
8 (Cabot's carbon black) and 50 parts
The mixture was kneaded using an Eiger motor mill M-250 (bead mill manufactured by Eiger Japan). The mill base resin solids / pigment ratio is 90/10.

To the obtained carbon black dispersion resin solution, add H808 (emulsion wax manufactured by Chukyo Yushi Co., Ltd.)
Fischer-Tropsch wax, particle size 0.5 μm,
45 parts (solid content 30%) was added, mixed and dispersed by Eiger Motor Mill M-250, and then the non-volatile content was adjusted to 51% with methyl ethyl ketone to prepare a mill base.

Next, 1 part was added to 300 parts of the mixture.
Normal sodium hydroxide aqueous solution 20.7 parts, isopropyl alcohol 34 parts, methyl ethyl ketone 30 parts, water 90
After mixing well, the internal temperature is maintained at 30 ° C., and while stirring, water (30 ° C.) is added to perform phase inversion emulsification to form resin particles (I). After 30 minutes, 300 parts of water are added. In addition, it was diluted.

Next, the organic solvent was removed by distillation under reduced pressure, the resin particles (I) were separated by filtration from the liquid medium, and the particles were redispersed in water. Subsequently, the pH of the dispersion was adjusted to 2.5 by adding a 1N aqueous hydrochloric acid solution, and the mixture was stirred for 30 minutes to convert the resin in the resin particles into the original carboxyl group-containing resin.

After the obtained resin particles were separated by filtration, the resin particles were further redispersed in water, the solid content was adjusted to 20%, and an aqueous dispersion solution of the resin particles (I) containing a colorant was prepared. Was adjusted. The pH of the aqueous dispersion solution of the resin particles is 4.
Nine.

The average particle size of the resin particles obtained here is:
7.8 μm as measured using Coulter Multisizer
Met. The practical sphericity of Wardell was a sphere of 0.96 or more. The resin particles obtained by drying were embedded in the resin, and the section obtained by cutting with a microtome was stained with ruthenium oxide, and then observed with a TEM (transmission electron microscope). As a result, the colorant and wax particles were included in the toner particles. It was confirmed that it was.

Reference Example 4 Preparation Example of Resin Particle (I) by Phase Inversion Emulsion Method Acid value: 4 mg · KOH / g, weight average molecular weight: 1200
0, 800 parts of methyl ethyl ketone was added to 1200 parts of a polyester resin having a glass transition point of 61 ° C. and a melt viscosity of 40000 poise at 100 ° C., and carbon black (ELFTEX8) 8 was added to the well-dissolved resin solution.
0 parts were added and mixed with stirring to sufficiently disperse. After the dispersion is completed, the solid content is reduced to 50% by methyl ethyl ketone.
And adjusted to a mill base.

To 200 parts of the mill base, 86 parts of methyl ethyl ketone and 4 parts of 1N ammonia water were added, and 225 parts of water was added with stirring to carry out phase inversion emulsification to form resin particles. 150 parts of water was added as dilution water, and 4 parts of 1N aqueous ammonia was added to increase the dispersion stability.

Next, the organic solvent was removed by distillation under reduced pressure to obtain an aqueous dispersion. A 1N aqueous hydrochloric acid solution was added to adjust the pH to 2.5, and the water slurry was treated with a centrifuge to remove fine powder. Then, the water slurry was passed through a filter (manufactured by Chisso Filter Co., Ltd.) to remove coarse particles. Was removed. The wet cake obtained by filtration and washing is washed with water for 20 minutes.
% Slurry to obtain an aqueous dispersion of the resin particles (I). The pH of this aqueous dispersion was 5.3.

The resin particles have a volume average particle size of 7.6.
In μm, the spherical shape had a practical sphericity of 0.96 or more by Wardell. Observation by a TEM of a cross section obtained by embedding the particles in a resin and cutting with a microtome revealed that the pigment was included in the particles and dispersed uniformly.

Reference Example 5 Preparation Example of Resin Particles (I) by Polymerization 240 parts of styrene 60 parts of butyl acrylate 3 parts of ethylene glycol dimethacrylate 6 parts of azobisisobutyronitrile 6 parts of dodecyl mercaptan 3 parts of carbon black 21 parts Viscol 550P 3 g [Polypropylene wax manufactured by Sanyo Chemical Industries, Ltd.]

The above mixture was treated with T.I. K. After dispersing with Robomix (Homomixer manufactured by Tokushu Kika Kogyo Co., Ltd.), ion-exchanged water 15 in which 18 parts of sodium polyacrylate was dissolved was dissolved.
Then, 00 g was added and dispersed and suspended. This mixture was placed in a 3 L flask equipped with a Faudler blade, and placed under a stream of nitrogen for 8 hours.
Suspension polymerization was carried out at 0 ° C. for 10 hours to prepare an aqueous dispersion of resin particles containing a colorant. The average particle size of the obtained resin particles was 7.7 μm. The practical sphericity of Wardell was a sphere of 0.96 or more.

The washing operation of filtering the aqueous resin particle dispersion and dispersing it in water again was repeated several times. Finally, the solid content was adjusted to 20%, and the resin containing the colorant was removed. An aqueous dispersion solution of the particles (I) was prepared. The pH of the aqueous dispersion solution of the resin particles was 5.3.

(Reference Example 6) Preparation Example of Fine Particles (II) Containing Carbon Black Into a 1 L wide-mouthed plastic bottle, the resin liquid 100 prepared in Reference Example 2 was added.
Parts, 150 parts of tetrahydrofuran and 1N hydrochloric acid aqueous solution 5
0 parts are weighed and mixed uniformly, then 33.5 parts of carbon black (Elftex8) are added, and then dispersed by a paint conditioner (using 400 parts of glass beads having a diameter of 1 mm) for 30 minutes.

This resin solution was transferred to a 2 L separable flask, and 1500 parts of water was added with stirring to perform phase inversion emulsification. The organic solvent was removed from the resulting dispersion of fine particles (II) by distillation under reduced pressure to obtain an aqueous dispersion of fine particles (II) of a basic group-containing resin containing carbon black. The solid content of the obtained aqueous solution is 7.5%, and the weight ratio of resin / carbon black is 60/40.

Example 1 Reference Example 3 was placed in a 10 L flask.
3,000 parts (solid content: 600 parts) of the aqueous dispersion solution of the resin particles (I) prepared in the above was charged, and the mixture was stirred.
After adding 144 parts (10.8 parts of solid content) of the aqueous dispersion of fine particles (II) containing carbon black prepared in the above, 0.1N ammonia water was added until the pH became 9 to 9.5. In addition, the fine particles (II) were deposited on the surface of the resin particles (I).

Next, the resultant was filtered, washed with water, separated from the wet cake, and dried to obtain toner particles having carbon black-containing basic group-containing resin fine particles fixed on the surface. The amounts of carbon black and basic group-containing resin added to the resin particles (I) were 0.6% by weight and 0.9%, respectively.
% By weight. The volume average particle diameter of the obtained toner particles is 7.8 μm, and when the particle surface is observed by SEM (scanning electron microscope), the fine particles (II) are fixed to the surface of the resin particles (I). Was confirmed. Further, the practical sphericity of Wardel was 0.96 or more.

The toner particles were charged into a Henschel mixer in which warm water of 60 ° C. was passed through the jacket and stirred and mixed to stabilize and homogenize the surface of the toner particles.
0 (manufactured by Nippon Aerosil) was externally added to obtain a positively chargeable toner.

Example 2 Reference Example 4 was added to a 10 L flask.
3,000 parts (solid content: 600 parts) of the aqueous dispersion solution of the resin particles (I) prepared in the above was charged, and the mixture was stirred.
160 parts (solid content: 12 parts) of the aqueous dispersion of the carbon black-containing fine particles (II) prepared in the above was added. Was obtained.
The volume average particle diameter of the toner particles is 7.6 μm,
Observation of the particle surface by SEM revealed that fine particles (II)
Was fixed to the surface of the resin particles (I). Further, the practical sphericity of Wardel was 0.96 or more. The toner particles were subjected to the same stirring and mixing treatment and external addition as in Example 1 to obtain a positively chargeable toner.

Example 3 Reference Example 5 was placed in a 10 L flask.
3,000 parts (solid content: 600 parts) of the aqueous dispersion solution of the resin particles (I) prepared in the above was charged, and the mixture was stirred.
144 parts (10.8 parts of solid content) of the aqueous dispersion of fine particles (II) containing carbon black prepared in the above was added, and the same operation as in Example 1 was carried out to obtain a basic group-containing resin containing carbon black. To obtain toner particles surface-treated.
The volume average particle diameter of the toner particles is 7.7 μm,
Observation of the particle surface by SEM confirmed that the fine particles (II) were fixed to the surface of the resin particles (I). Further, the practical sphericity of Wardel was 0.96 or more.
The toner particles were subjected to the same stirring and mixing treatment and external addition as in Example 1 to obtain a positively chargeable toner.

(Comparative Examples 1, 2, 3) Comparative Example 1 was carried out in the same manner as in Examples 1, 2, and 3 except that the type of the external additive was changed to a positively chargeable silica HDK H3050 (manufactured by Wacker Inc.). ,
A few positively chargeable toners were obtained.

(Evaluation Test of Toner) Four parts of each of the toners prepared in Examples and Comparative Examples were mixed with 96 parts of a fluorine / acrylic resin-coated magnetite carrier (average particle size: 80 μm) using a ball mill, and the mixing time was 10 minutes. , 30
The chargeability after 60 minutes was measured as shown in Table-1. Regarding the chargeability, the charge amount (μC / C) was measured using an E-SPART analyzer (manufactured by Hosokawa Micron Corporation).
g) and the reverse charge ratio (number%) were measured.

[0142]

[Table 1]

Example 1 in which negatively chargeable silica was externally added
The toners of Examples 2 and 3 have improved charging stability over time as compared with the toners of Comparative Examples 1, 2, and 3 to which positively-charged silica is externally added.

Further, the three kinds of toners produced in the examples were
When an image output test was performed using a commercially available copying machine (Z-52, manufactured by Sharp Corporation), good images were obtained in all cases.

[0145]

According to the present invention, an aqueous dispersion of resin particles (I) containing a binder resin and a colorant as essential components, and an aqueous dispersion of fine particles of a basic group-containing resin (II) containing carbon black as an essential component prepared separately. The liquid is mixed to precipitate fine particles (II) on the surface of the resin particles (I), and after drying, stirring and mixing under heating to stabilize and homogenize the toner particle surface. By externally adding inorganic fine particles, it is possible to obtain a spherical toner having positive chargeability and excellent in stability over time and charge amount distribution.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yukiko Soma 3-50-9, Daida, Setagaya-ku, Tokyo (72) Inventor Takayuki Ito 3-3-6-102 Higashi-Kojiya, Ota-ku, Tokyo F-term (reference) 2H005 AA15 AB03 AB06 CA28 CB13 CB18 DA02 DA03

Claims (7)

[Claims] 1. A toner having a basic group-containing resin containing carbon black as an essential component fixed on a surface of a resin particle (I) containing a colorant and a binder resin as essential components, a negatively chargeable toner. Positively chargeable toner to which inorganic fine particles are externally added. 2. The toner according to claim 1, wherein the inorganic fine particles are silica. 3. The method according to claim 1, wherein the basic group is a tertiary amino group.
The toner described in the above. 4. The toner particle has a Wardel practical sphericity of 0.9.
2. The toner according to claim 1, wherein the toner has a spherical shape of 5 or more. 5. An aqueous dispersion (A) of a resin particle (I) containing a colorant and a binder resin as essential components, and a basic agent which becomes self-water dispersible and / or water-soluble by neutralization. Fine particles having an average particle diameter smaller than that of the resin particles (I), obtained by mixing a mixture essentially containing a group-containing resin and carbon black with an aqueous medium in the presence of an acidic neutralizing agent and emulsifying the mixture by phase inversion. The aqueous dispersion (B) of (II) is uniformly mixed, and fine particles (II) are precipitated on the surface of the resin particles (I) with a basic neutralizing agent. Then, the liquid medium is removed and dried. The method for producing a toner according to claim 1, which is obtained by the above method. 6. A mixture comprising, as essential components, an acidic group-containing resin in which the resin particles (I) become self-water dispersible by neutralization and a colorant are mixed with an aqueous medium in the presence of a basic neutralizer. The production method according to claim 5, wherein the particles are spherical particles containing a colorant and obtained by phase inversion emulsification. 7. The method according to claim 5, wherein the resin particles (I) are spherical particles obtained by polymerizing a polymerizable monomer in which a colorant is dispersed in a liquid medium.