JPH08334928A - Production of electrophotographic toner - Google Patents

Abstract

PURPOSE: To obtain toner particles less liable to a variation in the quantity of electric charges according to environmental conditions, always giving a stable high quality image and having a prescribed average particle diameter and a narrower particle diameter distribution. CONSTITUTION: In a 1st process, a mixed compsn. contg. an anionic self-water- dispersible resin having acidic groups and acidic groups neutralized with a metallic basic compd., an org. solvent and a colorant as essential components is added to an aq. medium and subjected to phase inversion and emulsification or the aq. medium is added to the mixed compsn. and subjected to phase inversion and emulsification to form and disperse toner particles of the resin in which the colorant has been encapsulated in the aq. medium. In a 2nd process, the resultant dispersion of the toner particles in the aq. medium is mixed with an org. basic compd. and the acidic groups of the resin in the dispersed particles are neutralized with the org. basic compd. In a 3rd process, the aq. medium is removed from the dispersion to dry the toner particles. The objective electrophotographic toner is produced through the three processes.

Description

Detailed Description of the Invention

[0001]

The present invention relates to electrophotography, electrostatic recording,
The present invention relates to a method for producing a dry toner for developing an electrostatic latent image in electrostatic printing or the like.

[0002]

2. Description of the Related Art In electrophotography, dry developers are roughly classified into one-component developers using a toner itself in which a colorant is dispersed in a binder resin and two-component developers in which the toner and a carrier are mixed. can do.

In any case, when copying, the electrostatic latent image formed on the photoconductor is developed with these developers, and the toner powder imaged on the photoconductor is transferred to a transfer material such as paper or sheet. The image is fixed using heat, pressure, etc. to obtain a permanent image. At that time, in order to obtain a permanent image with sufficient image density and high resolution, it is necessary to adhere a predetermined amount of toner powder to the electrostatic latent image formed on the photoconductor faithfully to the latent image. .

Therefore, for practical toners, a characteristic that a sufficient amount of charge is rapidly developed by friction, and an environmental stability characteristic that the amount of charge can be reproduced almost the same under high temperature and high humidity or low temperature and low humidity conditions, etc. The so-called charging characteristic of is an important design factor. In addition, since it is necessary to be provided for development as individual particles rather than as agglomerates, fluidity is secured or powder environmental stability is ensured against changes in temperature and humidity. Toners are required to have many functions such as prevention of hot offset which induces image stain.

In recent years, a wet-process toner has attracted attention as a toner whose amount used as an image forming material for a copying machine, a laser printer and the like is increasing.

In the conventional toner manufacturing method, a mixture of a binder resin and a coloring agent is kneaded while being melted by a heating mixer, cooled, and then mechanically pulverized and finely pulverized by a pulverizer such as a jet mill. A method is generally used in which toner particles are classified and mechanically mixed with an external additive or the like, if necessary, and the shape of the particles is an angular polyhedral shape like crushed ice. I was trying.

On the other hand, Japanese Patent Laid-Open No. 5-66600 discloses a method for producing a toner by a wet method, which is completely different from the conventional mechanical pulverization method, in the presence of a colorant and the like in an aqueous medium. Wet processes have been described in which the colorant-encapsulated toner particles are obtained by phase inversion emulsification of the polymer to be obtained, whereby the toner particles are produced in one step.

A major feature of this wet process is that the toner shape can be made substantially spherical and that a uniform particle toner having a sharp particle size distribution can be easily produced. Such a spherical toner offers the advantage of being able to design a small particle size toner having excellent powder flowability, and is expected to develop into a high-performance toner that matches the market demand for high image quality and high resolution. There is.

[0009]

However, the toner obtained based on the above-mentioned conventional phase inversion emulsification method is toner particles obtained because the basic compound used for obtaining the toner is an organic basic compound. Has a wider particle size distribution,
To obtain toner particles having a narrow average particle size distribution with a predetermined average particle size, there is a drawback that classification is necessary or must be performed more sufficiently.

When the finally obtained toner particles have an unneutralized acidic group or are neutralized with a metal basic compound, the charge amount of the toner is represented by temperature and humidity. However, there is a problem in that stable high quality images cannot always be obtained as a result of large fluctuations depending on the environmental conditions.

In view of the above circumstances, the present invention provides an electronic device that can easily obtain toner particles having a predetermined average particle diameter with a narrower particle size distribution, that is excellent in environmental stability, and that has excellent charging characteristics. Provided is a method for producing a photographic toner, and more specifically, a high-quality image formed by ionic bond attachment of an organic basic compound to an acidic group on the surface of toner particles having a narrower particle size distribution and a predetermined average particle size. It is an object of the present invention to provide a method for producing a dry toner for electrophotography, which can stably print a large number of sheets.

[0012]

As a result of intensive studies, the inventors of the present invention have solved the above problems. That is, the present invention provides the following invention in order to solve the above problems.

A synthetic resin having an acidic group, an emulsifier and / or
Alternatively, a dispersion stabilizer, an organic solvent, and a mixed composition containing a colorant as an essential component are added to an aqueous medium for phase inversion emulsification, or an aqueous medium is added to the mixed composition for phase inversion emulsification. According to the first step of forming and dispersing the toner particles of the resin in which the colorant (E) is encapsulated in the aqueous medium, the toner particle aqueous medium dispersion obtained in the above step and the organic basic compound are mixed. A second step of neutralizing the acidic groups of the resin in the dispersed toner particles with the organic basic compound, and a third step of removing the aqueous medium from the aqueous dispersion of the toner particles obtained in the above step and drying. And a method of manufacturing an electrophotographic toner (referred to as a first invention).

A synthetic resin having an acidic group, an organic solvent,
A mixed composition containing a coloring agent as an essential component, an emulsifier and / or
Alternatively, a phase inversion emulsification is performed by adding it to an aqueous medium containing a dispersion stabilizer, or an phase inversion emulsification is performed by adding an aqueous medium containing an emulsifier and / or a dispersion stabilizer to the mixed composition, thereby coloring the aqueous medium. The first step of forming and dispersing the toner particles of the resin in which the agent (E) is encapsulated, the aqueous dispersion of the toner particles obtained in the above step and the organic basic compound are mixed, and Production of an electrophotographic toner comprising a second step of neutralizing an acidic group of a resin with the organic basic compound, and a third step of removing an aqueous medium from the aqueous dispersion of toner particles obtained in the step and drying the same. Method (referred to as a second invention)

Anionic self-water-dispersible resin (B) having an acidic group and an acidic group neutralized with a metal basic compound (A)
Or a mixed composition containing an organic solvent (D) and a colorant (E) as essential components is added to an aqueous medium for phase inversion emulsification, or
A first step of generating and dispersing toner particles of a resin (F) in which a colorant (E) is encapsulated in an aqueous medium by adding an aqueous medium to the mixed composition and performing phase inversion emulsification;
A second step of mixing the toner particle aqueous medium dispersion obtained in the above step and an organic basic compound, and neutralizing the acidic groups of the resin (B) in the dispersed toner particles with the organic basic compound; A method for producing an electrophotographic toner (referred to as a third invention), which comprises a third step of removing an aqueous medium from the aqueous dispersion of toner particles obtained in the above step and drying.

A mixed composition containing, as essential components, a synthetic resin (C) having an unneutralized acidic group, which is self-dispersible in water by neutralization, an organic solvent (D), and a colorant (E), The resin (C) is added to an aqueous medium containing a metal basic compound (A) necessary for neutralizing a part of the unneutralized acidic groups, and phase inversion emulsification is carried out, or a mixed composition is prepared. By adding an aqueous medium containing the compound (A) and subjecting it to phase inversion emulsification, an acidic group encapsulated with the colorant (E) and an acidic group neutralized with a metal basic compound are added to the aqueous medium. The first step for producing and dispersing the toner particles of the anionic self-water-dispersible resin (B), the aqueous dispersion of the toner particles obtained in the above step, and the organic basic compound are mixed, and First, the unneutralized acidic groups of the resin (B) are neutralized with the organic basic compound. Step, from the toner particles an aqueous medium dispersion liquid obtained in the step, a third step of drying to remove the aqueous medium, electrophotographic toners method for producing consisting (4th invention of.).

The present invention will be described based on the most typical first invention, and the other inventions will be described later.

The toner particles usable in the present invention are particles containing a colorant and a synthetic resin as essential components, and the resin containing the colorant dispersed therein has an acidic group (eg, carboxyl group, phosphoric acid group, A toner particle having a narrower particle size distribution and a predetermined average particle size, which contains a functional group having an anion forming ability such as a sulfonic acid group) and a part of the functional group is exposed on the surface of the particle. The resin acts as a binder resin. Such toner particles can be obtained in the first step of the present invention.

As the synthetic resin having such an acidic group,
It is a synthetic resin having an unneutralized acidic group in the molecule.
Of course, this may have a functional group other than the acidic group. Examples of this resin include epoxy resin, urethane resin, polyamide resin, acrylic resin, alkyd resin, and polyester resin. These may be used alone or in combination of two or more. Above all,
An acrylic resin, particularly a styrene / acrylate copolymer resin, from which a balance of powder fluidity and fixing property as a toner can be relatively easily obtained is preferable.

The above-mentioned resin has a molecular weight of a level necessary to develop sufficient mechanical strength, usually 3,000 to 200,000 as a weight average molecular weight, and acrylic resin has 5,000 to 150,000, and D
In SC measurement, glass transition temperature (Tg) is 50 to 1
The temperature is preferably 00 ° C, and for heat roll fixing, the temperature is preferably about 60 to 80 ° C.

When an acrylic resin is taken as an example of the resin, a polymer resin obtained by polymerizing a monomer such as (meth) acrylic acid ester can be given as a representative example. Specifically, for example, styrene. , Α
-Styrenes such as methylstyrene, chlorostyrene, vinylstyrene, monoolefins such as ethylene, propylene, butylene, isobutylene, diolefins such as butadiene and isoprene, vinyl acetate, propion vinyl, vinyl butyrate, vinyl benzoate, etc. Α of vinyl esters, methyl acrylate, ethyl acrylate, butyl acrylate, octyl acrylate, phenyl dodecyl acrylate, methyl methacrylate, ethyl methacrylate butyl methacrylate, dodecyl methacrylate, etc.
-Acrylic monomers such as vinyl ethers such as methylene aliphatic monocarboxylic acid esters, vinyl methyl ether, vinyl ethyl ether and vinyl butyl ether, vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and vinyl propenyl ketone, acrylic acid and methacrylic acid Acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, monobutyl itaconic acid, monobutyl maleate,
Acid phosphooxyethyl methacrylate, acid phosphooxypropyl methacrylate, 3-chloro-2
-Acrylamido-2-methylpropanesulfonic acid, 2
-The resin can be obtained by copolymerizing at least one kind of monomer selected from acid group-containing monomers such as sulfoethyl methacrylate.

Further, when describing the acrylic resin in detail, a polymer unsaturated group-containing oligomer having an acid group can also be used as a copolymerization component, such as maleic anhydride, fumaric acid, tetrahydrophthalic anhydride and endo. Vinyl-modified polyesters obtained by polycondensation or addition condensation of methylenetetrahydromaleic anhydride, α-terpinene maleic anhydride adduct and the like with monoallyl ether of triol, pentaerythrite diallyl ether or allyl glycidyl ether, dimethylolpropion Vinyl modified urethanes obtained by addition polymerization of diisocyanate with acid, glycerin monoallyl ether, 1,2 butadiene polyol, etc., vinyl modified by adding glycidyl group containing monomer to carboxyl group containing vinyl copolymer Epoxy, and the like can be mentioned.

As the polymerization initiator used for obtaining such a resin, of course, a usual one can be used.
Various peroxides such as benzoyl peroxide, di-t-butyl peroxide, cumene hydroperoxide, t-butyl peroxide or 2-ethylhexanoate; or azobisisobutyronitrile or azobisisovaleronitrile As mentioned above, various azo compounds and the like can be mentioned.

The resin itself may be obtained by solution polymerization in an organic solvent, suspension polymerization, emulsion polymerization, or bulk polymerization.

The polyester resin as the resin is
It can be obtained by condensation of a polyol and a polybasic acid, and an acid group can be easily introduced into an ordinary polyester resin by using an excessive amount of a dibasic acid such as phthalic acid.

As the colorant (E) in the toner particles used in the present invention, known and commonly used colorants can be used. Specifically, for example, carbon black, magnetic powder, nigrosine dye, aniline blue, calcyl blue. , Chrome Yellow, Ultramarine Blue, DuPont Oil Red, Quinoline Yellow, Methylene Blue Chloride,
Phthalocyanine blue, malachite green oxalate, lamp black, rose red algal, C.I. I. Pigment Red 122, C.I. I. Pigment Yellow 97,
C. I. Pigment Blue 15, ferrosoferric oxide, ferric oxide, iron powder, zinc oxide, selenium, etc.
They can be used in one kind or a combination of two or more kinds.

In the present invention, the toner obtained may be magnetic toner particles in which magnetic fine particles are dispersed in a binder resin. As the magnetic substance fine particles, any ferromagnetic substance that is normally used can be used.

Specific examples of the magnetic material include magnetic metals such as iron, cobalt and nickel, alloys of these, metal oxides such as cobalt-added iron oxide and chromium oxide, Mn / Zn ferrite, Ni / Zn ferrite and the like. Various kinds of ferrite,
In addition to magnetite, hematite, etc., the surface of these, silane coupling agent, aluminum coupling agent,
Powders such as those treated with a surface treatment agent such as a titanium coupling agent or those coated with a polymer can be used.

The weight ratio of the colorant (E) to the resin is not particularly limited, but the colorant (E) is 3 to 30% by weight when the total weight thereof is 100. Is preferred.

The method for obtaining an aqueous dispersion of toner particles having an acidic group on the surface of the particles in the present invention may be carried out according to the first step and is not particularly limited, but will be described step by step. Then, for example, the following method can be mentioned.

First, a mixed composition which is a solution of the organic solvent (D) of the resin in which the colorant (E) is dispersed is prepared.

Examples of the organic solvent (D) that can be used in preparing the organic solvent solution include 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; various ketones such as acetone, methyl ethyl ketone or methyl isobutyl ketone; various esters such as ethyl acetate or butyl acetate; various kinds such as butyl cellosolve acetate Ether ethers, and the like.

The non-volatile content of the organic solvent solution at that time is not particularly limited, but usually 10 to 70% by weight is suitable.

Then, a mixed composition comprising an organic solvent solution of a synthetic resin having an acidic group and containing an emulsifier and / or a dispersion stabilizer, in which the colorant (E) obtained above is dispersed, is transferred to an aqueous medium. By the phase emulsification, the toner particles are granulated in an aqueous medium to prepare an aqueous dispersion liquid of the toner particles.

In this case, of course, an aqueous medium may be added to the organic solvent solution for phase inversion emulsification, or the organic solvent solution may be added to the aqueous medium for phase inversion emulsification.
The former is preferable because toner particles having a narrower particle size distribution can be obtained. As a method of adding, dropping is generally used.

To facilitate the granulation in the phase inversion emulsification, an emulsifier and / or a dispersion stabilizer may be contained in the organic solvent solution and / or the aqueous medium.

As the dispersion stabilizer, a water-soluble polymer compound is generally used, and examples thereof include polyvinyl alcohol, polyvinylpyrrolidone, hydroxyethyl cellulose, carboxymethyl cellulose and cellulose gum.

Examples of the emulsifier include sodium dodecylbenzene sulfonate, sodium lauryl sulfate,
Examples thereof include anionic surfactants such as sodium dodecyldiphenyloxide disulfonate, nonionic surfactants such as polyoxyethylene lauryl ether, polyoxyethylene nonylphenol ether and the like. Of course,
The dispersion stabilizer and the emulsifier can be used in combination.

If a self-water-dispersible resin is used as the binder resin, phase inversion emulsification granulation can be carried out without using a dispersion stabilizer or an emulsifier.

That is, as the mixed composition used in the phase inversion emulsification in the first step, an anionic self-water-dispersible composition having not only an acidic group but also an acidic group neutralized with the metal basic compound (A) is used. When using a composition containing a synthetic resin (3rd
Invention) or a composition containing a synthetic resin having an unneutralized acidic group, which can be self-water-dispersed by neutralization, as the mixed composition used in the phase inversion emulsification in the first step, and as the aqueous medium, When an aqueous medium containing a metal-basic compound sufficient to neutralize at least a part of the unneutralized acidic groups of the synthetic resin so that the resin is dispersed in water (the fourth invention), the result is First, since the resin component itself has water dispersibility (self-water dispersibility) during phase inversion emulsification,
2 The emulsifier and dispersion stabilizer which are essential constituents in the invention are not particularly required.

Among the first to fourth inventions, the third to fourth inventions do not use an emulsifier or a dispersion stabilizer which may adversely affect the charging property, fluidity or fixing property of the finally obtained toner. Are more preferable than the first and second inventions. First to first
2 Even when carrying out the invention, it is preferable to use the amount thereof as small as possible as long as the water dispersibility of the resin is achieved.

The first to fourth inventions thus obtained
The aqueous dispersion of toner particles obtained in the step is spherical particles of a binder resin in which the colorant (E) is encapsulated (encapsulated), and the surface of the particle has an acidic group, or the acidic group and the acidic group. An aqueous dispersion of toner particles in which a synthetic resin, which is a binder containing at least a part of the acidic group neutralized with the metal basic compound (A) to form a salt structure, is dispersed in an aqueous medium.

The self-water-dispersible resin is a synthetic resin containing in its molecule a functional group capable of becoming a hydrophilic group by neutralization, and some or all of the functional groups capable of becoming hydrophilic are neutralized by a neutralizing agent. In this case, the resin has the ability to form a stable aqueous dispersion without using an emulsifier or a dispersion stabilizer.

Anionic self-water-dispersible resin (B) having an acidic group and an acidic group neutralized with a metal basic compound (A)
Is an anion-type self-water-dispersible synthetic resin having both an unneutralized acidic group and a neutralized acidic group in its molecule.

Examples of the acidic group in these resins and the functional group capable of becoming a hydrophilic group by neutralization include so-called acidic groups such as a carboxyl group, a phosphoric acid group and a sulfonic acid group, and a carboxy group-containing anionic resin is taken as an example. If you take
The content of the carboxyl group that can become an anionic hydrophilic group by neutralization of the resin is not particularly limited, but an acid value of about 40 or more facilitates particle formation by the phase inversion emulsification method. Therefore, it is preferable. Particularly preferably, the acid value is 50 to 150. As for the others, those having the same elements and characteristics as the above-mentioned synthetic resin having an acidic group can be used.

The resin (B) can also be produced according to the method for producing a synthetic resin having an acidic group.

The organic basic compound used in the second step of the above-mentioned first to second inventions is not limited to its kind, and a compound which easily forms a cation ion in water can be used. Moreover, the metal basic compound (A) used for neutralizing the acidic groups contained in each synthetic resin used in the first step of the third to fourth inventions and the organic basic compound used in the second step are The resin is not limited to the kind as long as it can exhibit hydrophilicity to the extent that it can be self-dispersed in an aqueous medium, and a compound that easily generates a cation ion in water is used. it can.

Examples of the metal basic compound (A) used for neutralizing the acidic group include sodium hydroxide, potassium hydroxide, lithium hydroxide and the like. Others, such as sodium silicate, potassium silicate, dibasic sodium phosphate, tribasic sodium phosphate, dibasic ammonium phosphate, tribasic ammonium phosphate, sodium metasilicate, sodium carbonate, ammonia and the like compounds described above ( Inorganic basic compounds other than A) can be used in combination therewith. These compounds (A) may be used as they are, or may be dissolved in a solvent and used as a solution.

The phase-inversion emulsification granulation in the first step of the third to fourth inventions in which the self-water-dispersible resin (B) becomes a binder resin is, for example, an acidic group in which a colorant (E) is dispersed. Having a compound (A) sufficient to make the synthetic resin self-water dispersible in an organic solvent (E) solution of a synthetic resin which becomes self-water dispersible when at least a part thereof is neutralized, A mixed composition in which an acidic group is neutralized in a resin and converted into the resin (B) to be dispersed, and then the mixed composition is mixed with an aqueous medium for phase inversion emulsification, or at least one of them having an acidic group. An organic solvent (E) solution of a synthetic resin that becomes self-water dispersible when a part is neutralized is used as a mixed composition, and an aqueous medium containing the above compound (A) sufficient to make the resin self-water dispersible. It is carried out by mixing and phase inversion emulsification to obtain the colorant (E). Are spherical particles of the packaging has been binder resin, comprising the acidic group on the particle surface, can be a toner particle aqueous dispersion was dispersed in an aqueous medium.

In this case, as in the first and second inventions, the aqueous medium side may be added to the mixed composition side, or conversely, the mixed composition side may be added to the aqueous medium side. However, the first
The former is preferable for the same reason as in the case of the second invention. The method of addition is the same as above.

In addition to the above, the 3rd to 4th inventions are characterized by the characteristics of the synthetic resin used in the first step and the basic compound used for neutralization, and compared with the 1st and 2nd inventions, toner of any specific particle size There is a particularly significant effect that particles can be obtained with a narrower particle size distribution. Further, a separate step such as a water washing step for separately removing the dispersion stabilizer, the emulsifier, etc. is unnecessary, and it is preferable in that the productivity is excellent. The phase inversion emulsification method using a self-water dispersible resin that does not use an emulsifier or a dispersion stabilizer does not leave the emulsifier or the dispersion stabilizer in the final toner powder as compared with other toners of the phase inversion emulsification method. Since it does not exist, a spherical dry toner having more stable charging characteristics can be obtained.

As an invention similar to the third invention, the present invention uses an anionic self-water-dispersible resin having only an acidic group neutralized with a metal basic compound in the first step, In addition, an invention is also included in which, between the first step and the second step, reverse neutralization is performed so that at least a part of the neutralized acidic group is returned to the unneutralized acidic group. Also with this method, the same technical effect as the first step of the present invention can be obtained.

According to the fourth aspect of the present invention,
In the first step, an aqueous medium containing a metal basic compound necessary for neutralizing all the unneutralized acidic groups in the resin (C) is used, and in the same manner as the first step, It also includes an invention in which during the second step, reverse neutralization is carried out such that at least a part of the neutralized acidic groups is returned to the unneutralized acidic groups. Also with this method, the same technical effect as the first step of the present invention can be obtained.

For each of the above-mentioned reverse neutralization, the methods and conditions described later can be similarly adopted.

In obtaining the electrophotographic toner of the present invention, auxiliary agents such as waxes and charge control agents may be incorporated, if desired, in any step of its production.

Examples of the auxiliaries include waxes such as polyethylene wax, polypropylene wax and paraffin wax, metal soaps, lubricants such as zinc stearate,
Alternatively, an abrasive such as cerium oxide or silicon carbide, a copper phthalocyanine, perylene, quinacridone, an azo pigment, an azo metal-containing dye, a charge control agent such as an azochrome complex, etc. may be mentioned.

The second step of the present invention is common to the first to fourth inventions. In this second step, the aqueous dispersion of toner particles obtained in the first step is mixed with an organic basic compound, and the acidic groups on the resin surface in the dispersed toner particles in an aqueous medium are converted to the organic basic compound. Neutralize with. As a result, the unneutralized acidic group is neutralized, and a salt structure in which the compound is attached is formed by an ionic bond.

The organic basic compound used at this time is an organic compound capable of forming an ion pair with the above-mentioned acidic group, and specifically, for example, trimethylamine, triethylamine,
Tri-n-butylamine, triallylamine, tri-n
-Pentylamine, trihexylamine, tribenzylamine, triphenylamine, dimethyl-n-laurylamine, dimethyl-n-palmitylamine, dimethyl-
Tertiary amines such as n-stearylamine, dimethyl-benzylamine, dimethylaniline, dimethylamine,
Diethylamine, diisopropylamine, di-n-butylamine, diallylamine, di-n-pentylamine,
Secondary amines such as dihexylamine, dibenzylamine, diphenylamine, etc., primary amines such as monomethylamine, monoethylamine, monoisopropylamine, mono-t-butylamine, monoiso-butylamine, mono-n-butylamine, etc. Examples thereof include 2-aminobenzotrifluoride, m-aminoacetophenone, 4-aminoacetanilide, mono-, di-, or triethanolamine, mono-, di-, or triisopropanolamine, ethyleneimine, ethylenediimine. These compounds may be used as they are, or may be dissolved in a solvent and used as a solution.

As the organic basic compound, it is preferable to use an organic amine compound represented by the following general formula among the above compounds.

[0060]

Embedded image

The second step is preferably carried out with stirring. Also in this case, the organic basic compound side may be added to the toner particle aqueous dispersion side, or conversely, the toner particle aqueous dispersion side may be added to the organic basic compound side, but the former is preferable.

The amount of the organic basic compound used in the present invention may be 0.3 to 100 mol% with respect to the acidic groups on the surface of the toner particles, and more preferably 50.
Addition of ˜100 mol% equivalent gives good results. Within this range, the sufficient effect of the present invention can be obtained,
In addition, the characteristics of the toner particles themselves are less likely to be impaired.

The amount of acidic groups on the surface of the toner particles can be determined by, for example, a titration method. For example, the concentration can be calculated by the following method. To the granulated carboxyl group-containing toner particle aqueous dispersion, an excess of 1N aqueous sodium hydroxide solution was added,
The mixture is sufficiently stirred and mixed to add sodium ions to the acidic groups on the surface of the toner particles. Then, the aqueous dispersion of the toner particles is filtered and washed to remove excess sodium hydroxide other than those ionically bonded to the functional groups on the surface of the particles.
Next, the toner particles are redispersed in water, and a 1N aqueous hydrochloric acid solution is added dropwise while stirring until the pH of the aqueous dispersion becomes 3. The amount of sodium ions on the surface of the toner particles, that is, the amount of carboxyl groups can be calculated from the dropped amount of this 1N hydrochloric acid.

In any of the first to fourth inventions, the transition from the first step to the second step may be carried out after the organic solvent (D) has been removed from the aqueous medium in advance. At that time, the organic solvent (D) can be removed by, for example, vacuum distillation.

When the synthetic resin in the toner particles is the resin (B) as in the third to fourth inventions, the acidic groups neutralized with the metal basic compound (A) are the original unneutralized. Acid is added to the aqueous dispersion of the toner particles obtained in the first step for reverse neutralization to remove the metal basic compound adhering to the surface of the particles, followed by filtration and washing. And then the second
The steps can also be performed.

Of course, in the third to fourth inventions, the above treatments are combined to obtain an aqueous dispersion of toner particles from which only the organic solvent (D) has been removed, and the aqueous dispersion of the toner particles and the above compound (A).
Is mixed with an acid having an opposite polarity or an aqueous solution thereof, and returns the neutralized acidic group to the original unneutralized acidic group,
It is also possible to prepare a mixture in which a part or all of it is anionic synthetic resin that can become self-water dispersible by neutralization, and then redisperse it in an aqueous medium, and use it to perform the second step. I can.

As the acid, any of known and commonly used acids can be used, for example, organic acids such as oxalic acid, formic acid and acetic acid, and inorganic acids such as hydrochloric acid, sulfuric acid, sulfonic acid and phosphoric acid. As the acid, a strong acid is preferable. Usually 0.1-1
A hydrochloric acid aqueous solution of N is used.

A toner powder can be obtained by removing the aqueous medium from the aqueous dispersion of the toner particles obtained in the second step and drying. In removing the aqueous medium from the dispersion, any effective method such as decantation or filtration can be adopted.

In this case, when the dispersion liquid contains the organic solvent (D), it is preferable to remove it in the same manner as described above.

Any known and commonly used method can be adopted for the above-mentioned drying. For example, hot-air drying may be performed at a temperature at which toner particles are not thermally fused or aggregated, or freeze-drying may be used. There is also a method in which the toner particles are separated from the aqueous medium and dried at the same time by using a spray dryer or the like.

The toner particles thus obtained are a powder having a narrow particle size distribution and a uniform particle size, and the temperature, humidity, and other surrounding environment are higher than when the acidic groups are directly exposed on the particle surface. Since it has a constant amount of charge stably with respect to the change of, the fluctuation of the image density is small in actual use, and a faithful and clear image can be obtained on the original.

As the particle size of the toner powder of the present invention, any size can be selected within a practical level as a toner. The volume average particle diameter is 3 to 30 μm, preferably 4 to 12 in view of the matching property with the current machine.
The range of μm is preferable.

The electrophotographic toner of the present invention can be used as a non-magnetic one-component toner or a magnetic one-component toner, or as a two-component developer when combined with a carrier, and is particularly suitable as a two-component developer. The characteristics can be obtained.

As the carrier, any known carrier can be used, and examples thereof include iron, nickel, copper, zinc,
Powders of metals such as cobalt, manganese, chromium, rare earths and alloys or oxides thereof, surface-treated glass, silica and the like can be used. Needless to say, a resin-coated carrier such as an acrylic resin-coated carrier, a fluororesin-coated carrier, or a silicone resin-coated carrier can also be used. As the carrier, for example, a carrier of about 20 to 200 microns is used.

When a two-component electrostatic image developer is obtained from the toner obtained in the present invention and a carrier, for example, the toner is mixed in a ratio of 1 to 15 parts by weight of toner per 100 parts by weight of carrier. You can use it.

The toner obtained by the conventional phase inversion emulsification method has a problem that it is difficult to obtain the stable charging characteristics as obtained by the toner manufactured by the conventional mechanical dry pulverization method. Specifically, in the friction with a carrier or a blade which is usually used in a copying machine or a laser printer, a sufficient charge amount cannot be expressed in the toner, or even if an appropriate charge amount can be given. There is a problem that the rising speed is slow, and further, the charge amount largely changes due to environmental changes such as temperature and humidity, so that stable high quality images cannot be obtained. The present invention also eliminates this point.

[0077]

EXAMPLES The present invention will be described more specifically below by showing examples of the present invention. However, the invention is not limited to these examples.

(Example 1) 200 g of methyl ethyl ketone
Was placed in a reactor and heated to 80 ° C. Then, the mixture in the proportions shown below was added dropwise over about 2 hours. Meanwhile, the reaction was carried out in a nitrogen stream.

Methacrylic acid 45 g Styrene 207 g 2-Ethylhexyl acrylate 33 g Methyl methacrylate 15 g Perbutyl O [Nippon Shokubai Co., Ltd.] 3 g Methyl ethyl ketone 12 g

One hour after the completion of the dropping of the above mixture, 0.25 g of perbutyl O was additionally added, and then 0.25 g was added within 2 hours and the reaction was continued for 24 hours. After completion of the reaction, a styrene-acrylic copolymer resin solution having a nonvolatile content of 54% by weight and capable of becoming self-dispersible in water was obtained. This resin had an acid value of 100 and a weight average molecular weight of 40,000.

200 g of this copolymer solution, 65 g of methyl ethyl ketone, 91 g of acetone and "MA-100".
[Carbon black manufactured by Mitsubishi Kasei Co., Ltd.] 12.0 g
Was mixed for 1 hour with a kneader "Eiger M-250VSE-EXJ" (kneader manufactured by Eiger, USA), 19.3 g of 1N-sodium hydroxide aqueous solution was added, and the mixture was stirred at 350 rpm using a three-one motor. While water was added dropwise, phase inversion emulsification was carried out to obtain an aqueous dispersion of toner particles containing a colorant and comprising a self-water-dispersible resin. When the toner particles were measured with a Coulter counter, they were toner particles having an average particle diameter of 8 microns. Further, it was confirmed by observation with an electron microscope that the toner particles were truly spherical.

Next, the organic solvent was removed by vacuum distillation so that the temperature became lower than the softening point of the toner particles, and the pH was adjusted to 6
A 0.01N aqueous hydrochloric acid solution was added to the mixture until filtration and filtered and washed, and then the toner particles were returned to water to obtain an aqueous dispersion of toner particles. To this aqueous dispersion of toner particles, 0.18 g of triethylamine was added, and the mixture was sufficiently stirred to attach triethylamine to 85% of the carboxyl groups on the surface.

Then, it was filtered and treated with a freeze dryer for 3 days to obtain a dry toner. This toner had excellent fluidity, and no aggregation of particles was observed. The particle size distribution was also extremely sharp.

When this dry toner was analyzed by gas chromatography, the amount of triethylamine used was detected, and it was confirmed that triethylamine was strongly ion-bonded to the surface of the toner particles.

The dry toner thus obtained has an average particle diameter of 80 μm.
The developer was adjusted by mixing and stirring 5 parts by weight with respect to 100 parts by weight of the ferrite carrier of m, and the environmental stability of the charging characteristics was confirmed. It was -51.5 μC / g under low temperature and low humidity conditions of 10 ° C. and 40% RH, and −52.9 μC / g under high temperature and high humidity conditions of 35 ° C. and 80% RH, showing almost the same charge amount. . When a copy test was carried out using a commercially available electronic copying machine using this developer, even when the room temperature was changed to high temperature / high humidity / low temperature / low humidity, a uniform image density was obtained.
A clear image faithful to 0000 or more originals was obtained.

(Example 2) In the same manner as in Example 1, an aqueous dispersion of toner particles containing a carboxyl group on the surface was prepared. To this toner particle dispersion liquid, tri-n-butylamine (0.29 g) was added, and the surface carboxyl group 74
%, Sufficient agitation was performed to deposit tri-n-butylamine. Then, the toner particle dispersion liquid was filtered and treated with a freeze dryer for 3 days to obtain a dry toner. This toner had excellent fluidity, and no aggregation of particles was observed. Similar to Example 1, the average particle size was a spherical shape of 8 microns, and the particle size distribution was extremely sharp.

The dry toner thus obtained has an average particle size of 80 μm.
A developer was prepared by mixing and stirring 5 parts by weight with respect to 100 parts by weight of the ferrite carrier of m. When a copy test was conducted with a commercially available electronic copying machine using this developer,
Even when the room temperature was changed to high temperature / high humidity / low temperature / low humidity, a clear image faithful to 20,000 or more originals having a uniform image density was obtained.

Comparative Example 1 A dry toner was prepared without adding the triethylamine used in Example 1. That is,
A toner in which an amino compound was not ionically added to the carboxyl groups on the surface of the toner particles was prepared. Similar to the toner obtained in Example 1, this toner had excellent fluidity, and no aggregation of particles was observed.

However, the developer was adjusted by mixing and stirring at a ratio of 5 parts by weight to 100 parts by weight of a ferrite carrier having an average particle diameter of 80 μm, and when the environmental stability of the charging characteristics was confirmed, 10 ° C., 40% RH In the low temperature and low humidity condition, the charge amount was -72.1 μC / g, and under the high temperature and high humidity condition of 35 ° C. and 80% RH, the charge amount was −58.4 μC / g, and the fluctuation range was large. When a copy test was conducted with a commercially available electronic copying machine using this developer, when the room temperature was changed to high temperature / high humidity / low temperature / low humidity, the image density changed and a clear image faithful to the original was obtained. I couldn't.

[0090]

In the present invention, an aqueous medium dispersion of toner particles having an acidic group on the particle surface, which is obtained by the phase inversion emulsification method, and an organic basic compound are mixed, and the acidic group and the compound are ionized. Since the combined toner has a salt structure, the final toner obtained by drying can stably maintain a predetermined charge amount even if the environment changes during use, resulting in a uniform image density. A particularly remarkable effect that a clear image that is faithful to the original can be obtained from the large number of sheets that it has.

Claims (7)

[Claims] 1. A method of phase-inversion emulsification by adding a mixed composition comprising a synthetic resin having an acidic group, an emulsifier and / or a dispersion stabilizer, an organic solvent and a colorant as essential components to an aqueous medium. Obtained by the first step and the above step, in which an aqueous medium is added to the mixed composition to perform phase inversion emulsification to generate and disperse the toner particles of the resin in which the colorant (E) is encapsulated in the aqueous medium. Second, the aqueous dispersion of the toner particles thus obtained is mixed with an organic basic compound, and the acidic groups of the resin in the dispersed toner particles are neutralized with the organic basic compound.
And a third step of removing the aqueous medium from the aqueous dispersion of the toner particles obtained in the above step and drying the aqueous medium. 2. A method of phase inversion emulsification by adding a mixed composition comprising a synthetic resin having an acidic group, an organic solvent and a colorant as essential components to an aqueous medium containing an emulsifier and / or a dispersion stabilizer. By adding an aqueous medium containing an emulsifier and / or a dispersion stabilizer to the mixed composition to perform phase inversion emulsification, thereby producing and dispersing toner particles of the resin in which the colorant (E) is encapsulated in the aqueous medium. A first step of mixing, an aqueous medium dispersion of the toner particles obtained in the step and an organic basic compound are mixed, and the acidic groups of the resin in the dispersed toner particles are neutralized with the organic basic compound. And a third step of removing the aqueous medium from the aqueous dispersion of the toner particles obtained in the above step and drying the aqueous medium. 3. An anionic self-water-dispersible resin (B) having an acidic group and an acidic group neutralized with a metal basic compound (A), an organic solvent (D), and a colorant (E). A mixed composition as an essential component is added to an aqueous medium for phase inversion emulsification, or an aqueous medium is added to the mixed composition for phase inversion emulsification, whereby the colorant (E) is encapsulated in the aqueous medium. For generating and dispersing the toner particles of the resin (B)
Step, mixing the aqueous dispersion of toner particles obtained in the above step with an organic basic compound, and neutralizing the acidic groups of the resin (B) in the dispersed toner particles with the organic basic compound And a third step of removing the aqueous medium from the aqueous dispersion of the toner particles obtained in the above step and drying the aqueous medium. 4. A synthetic resin (C) having an unneutralized acidic group, which is self-dispersible in water by neutralization, and an organic solvent (D).
A mixed composition containing a colorant (E) as an essential component and an aqueous solution containing a metal basic compound (A) necessary for neutralizing a part of the unneutralized acidic groups in the resin (C). The colorant (E) was encapsulated in the aqueous medium by performing phase inversion emulsification by adding it to a medium or by adding an aqueous medium containing the compound (A) to the mixed composition. A first step of forming and dispersing toner particles of an anionic self-water-dispersible resin (B) having an acidic group and an acidic group neutralized with a metal basic compound (A), the toner particle aqueous solution obtained in the above step The second step obtained by mixing the medium dispersion and the organic basic compound and neutralizing the unneutralized acidic groups of the resin (B) in the dispersed toner particles with the organic basic compound From the third step of removing the aqueous medium from the toner particle aqueous medium dispersion and drying. A method of manufacturing an electronic photograph toner that. 5. Anionic self-water dispersibility having an acidic group and an acidic group neutralized with a metal basic compound in the toner particles dispersed in the aqueous dispersion of toner particles obtained in the first step. Acid is added to the toner particle aqueous medium dispersion so that the acidic group of the resin (B) neutralized with the metal basic compound (A) becomes the original unneutralized acidic group. 5. The second step is carried out after mashing and filtering and washing.
The manufacturing method described. 6. The second step is carried out after removing the organic solvent contained therein from the aqueous dispersion of toner particles in the aqueous medium obtained in the first step.
The manufacturing method described. 7. The synthetic resin having an acidic group or the anionic self-water-dispersible resin (B) having an acidic group neutralized with an acidic group and a metal basic compound (A) in the toner particles,
A synthetic resin having one kind of acidic group selected from the group consisting of a carboxyl group, a phosphoric acid group and a sulfonic acid group on the surface, or one kind selected from the group consisting of a carboxyl group, a phosphoric acid group and a sulfonic acid group on the surface An anionic self-water-dispersible resin having an acidic group and an acidic group neutralized with a metal basic compound (A), wherein the organic basic compound is represented by the following general formula: 2. Toner particles having a structure in which the amino compound is attached to the acidic group, which is an amino compound represented by:
The manufacturing method according to 2, 3, 4, 5 or 6.