JPH08179558A - Production of electrophotographic toner - Google Patents

Abstract

PURPOSE: To obtain a dry toner having lowered adhesiveness to a photo-sensitive drum, hardly causing deposition on the drum even after the repetition of copying is increased, excellent in stability of a charged state and giving uniform image density with further enhanced productivity while preventing aggregation in a process for drying a spherical toner produced by a wet process by removing the aq. medium of the toner. CONSTITUTION: An aq. dispersion of toner particles consisting of a colorant and a resin binder is mixed with water-insoluble or water-nonswellable fine particles of a self-water-dispersible resin or a resin convertible into a self-water- dispersible resin by neutralization. The average particle diameter of the fine particles is smaller than that of the toner particles. After dispersion, the aq. medium is removed to carry out drying and the objective toner made of toner particles with the fine particles stuck to the surfaces is obtd.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Among electrophotographic toners widely used as image forming materials for copying machines, laser printers, fax machines and the like, spherical toners have attracted attention.

In the conventional toner manufacturing method, a mixture of a binder resin and a colorant is melted and kneaded by a heating mixing device, cooled, and then mechanically coarsely 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 particle shape is an irregular shape like crushed ice. .

On the other hand, the spherical toner production method is completely different from the conventional mechanical pulverization method, and in the presence of a colorant or the like in a water medium, a monomer or polymer to be a binder resin is chemically reacted or phase inversion emulsified. Toner particles are produced in one step by the wet process of. 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 spherical toner is
It offers the advantage of being able to design small particle size toners with excellent powder flowability, and is expected to develop into high-performance toners that meet the market requirements for high image quality and high resolution.

However, the spherical toner produced by the wet process has a problem that a great amount of energy and time are required for a drying step for finally obtaining a dry toner, that is, a step of removing an aqueous medium. When the treatment is performed at a high temperature in order to increase the drying rate, the toner particles are melted and fused, which makes it difficult to obtain toner particles having a desired particle diameter, which causes a problem that a conventional treatment method such as a spray dry method cannot be applied. On the other hand, on the other hand, if a freeze-drying method which requires a small amount of heat is not used, it takes a long time to dry, and there is a problem that rapid processing cannot be performed.

[0006]

In view of the above circumstances, the present invention provides a method for producing a dry toner which improves the productivity of a wet process toner, and more specifically,
It is an object of the present invention to provide a manufacturing method for obtaining a dry toner by a wet manufacturing method, which can significantly reduce the drying time of the wet manufacturing toner.

[0007]

As a result of intensive studies, the inventors of the present invention have solved the above problems. That is, in order to solve the above problems, the present invention provides an aqueous dispersion of toner particles in which toner particles (C) comprising a colorant (A) and a binder resin (B) are dispersed in an aqueous medium. Is smaller than the particles, and the water-insoluble or water-swellable fine particles (F) of the resin (D) or the self-water-dispersible resin (E) which can become self-water dispersible by neutralization are mixed and dispersed, Provided is a method for producing toner particles in which fine particles (F) are attached to the surfaces of particles (C), which comprises removing an aqueous medium and drying.

In the present invention, an aqueous toner particle dispersion is used in which toner particles (C) comprising a colorant (A) and a binder resin (B) are dispersed in an aqueous medium. The toner particles (C) need to be particles that include the colorant (A) and the binder resin (B) as essential components. In the present invention, “encapsulation” refers to a state in which the colorant (A) particles are dispersed in the resin (B) in addition to the state in which the colorant (A) particles are included in the resin (B). It also includes things.

In the present invention, as the colorant (A), any of known and commonly used ones can be used. For example, carbon black, magnetic powder, dyes and pigments such as nigrosine dye, aniline blue, calcoil blue and chrome yellow. , Ultramarine Blue, DuPont Oil Red, Quinoline Yellow, Methylene Blue Chloride, Phthalocyanine Blue, Malachite Green Oxalate,
Lamp black, rose red iron oxide, C.I. I. Pigment Red 122, C.I. I. Pigment Yellow 97, C.I.
I. Pigment Blue 15, ferrosoferric oxide, ferric oxide,
Examples thereof include iron powder, zinc oxide, and selenium, and they can be used alone or in combination of two or more.

As the colorant (A), it is preferable to select and use a colorant having a higher affinity for the binder resin (B) than that for water. As an example, it is preferable to use a water-insoluble or sparingly water-soluble coloring agent.

In the present invention, the toner particles (C) may be magnetic toner particles in which magnetic fine particles are dispersed in the binder resin (B). As the magnetic substance fine particles, any ferromagnetic substance that is normally used can be used. Specifically, magnetic metals such as iron, cobalt and nickel, alloys thereof, iron oxides containing cobalt, metal oxides such as chromium oxide, Mn / Zn ferrite, Ni / Z.
Various ferrites such as n-ferrite, magnetite, hematite, etc., and those whose surface is treated with a surface treatment agent such as a silane coupling agent, an aluminum coupling agent, a titanium coupling agent, and those coated with a polymer. Can be used.

The binder resin (B) is usually DSC.
Glass transition temperature (Tg) is 50
What is (B1) which is -100 degreeC is used, and for heat roll fixing, it is preferable that it is about 60-80 degreeC. Further, if the resin (B) or (C) suitable for the softening point is shown, it is 30 to 90 ° C.

As the binder resin (B), any of known and commonly used binder resins can be used. For example, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-butadiene copolymer, In addition to polystyrene, polyethylene, polypropylene, styrene-
Examples thereof include acrylonitrile copolymer and styrene-maleic anhydride copolymer. Furthermore, epoxy resin, urethane resin, polyamide resin, alkyd resin,
A polyester resin etc. can also be mentioned. Above all,
Acrylic resin, especially styrene /, which is relatively easy to obtain a balance of powder fluidity and fixability as a toner
Acrylate copolymer resins are preferred.

The styrene resin is a resin obtained by polymerizing styrene as an essential component, and the acrylic resin is (meth)
A resin obtained by polymerizing an acrylate ester as an essential component, and any of them may be a homopolymer. Specifically, for example, styrenes such as styrene, α-methylstyrene, chlorostyrene, vinylstyrene, etc. , Ethylene, propylene, butylene, isobutylene and other monoolefins, butadiene and isoprene and other diolefins, vinyl acetate, propion vinyl, vinyl butyrate, vinyl benzoate and other vinyl esters, methyl acrylate, ethyl acrylate, acrylic Α-methylene aliphatic monocarboxylic acid esters such as butyl acrylate, octyl acrylate, phenyl acrylate dodecyl acrylate, methyl methacrylate, ethyl methacrylate butyl methacrylate, dodecyl methacrylate, vinyl methyl ether, vinyl ethyl ether, vinyl butyl Acrylic monomers such as vinyl ethers such as ethers, vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and vinyl propenyl ketone, acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, monobutyl itaconate, maleic acid Monobutyl, acid phosphooxyethyl methacrylate, acid phosphooxypropyl methacrylate, 3-chloro-2-acrylamido-2-methylpropanesulfonic acid, acid group-containing monomers such as 2-sulfoethyl methacrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, Dibutylaminoethyl acrylate, N-ethyl-N-phenylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate Obtained by polymerizing at least one monomer selected from base group-containing monomers such as styrene, dibutylaminoethyl methacrylate, and N-ethyl-N-phenylaminoethyl methacrylate with styrene or (meth) acrylic acid ester as an essential component. Other copolymers can be exemplified.

The weight ratio of the colorant (A) and the resin (B) is not particularly limited, but when the total weight thereof is 100, the colorant (A) becomes 3 to 30% by weight. It is preferable to do so.

In obtaining the aqueous dispersion of toner particles used in the present invention, auxiliary agents such as waxes and charge control agents may be added, 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.

As the particle size of the toner powder comprising the toner particles (C) used in the present invention, any size can be selected within a practical level as a toner. The volume average particle size is 3 to 3 from the matching property with the current machine.
A thickness of 0 μm, preferably 4 to 12 μm is suitable.

As the toner particles (C), substantially spherical particles are preferably used. Spherical toner particles (C) are preferable because they have good fluidity. The toner particles (C) have a practical sphericity of Wader (ratio between the diameter of a circle having an area equal to the projected area of the particle and the diameter of the smallest circle circumscribing the projected image of the particle) of 0.95 to 1.00. Preferably there is.

In obtaining the aqueous dispersion of the toner particles (C) of the present invention, any known and conventional method can be adopted. Specifically, for example, in the presence of a dispersion stabilizer, the colorant (A) and the reactive monomer capable of forming the binder resin (B) are dispersed and suspended in water to prepare a polymerization initiator. In existence,
There is a method in which a polymerization reaction is carried out with stirring to obtain a spherical aqueous dispersion of toner particles in which the colorant (A) is included in the binder resin (B) (the dispersion obtained by this method). Hereinafter, the liquid is referred to as a suspension polymerization method dispersion liquid).

In this method, as the reactive monomer capable of forming the binder resin (B), those which can be used for obtaining the polymer used for the binder resin (B) are as described above. Either can be used. If necessary, a small amount of a reactive monomer having two or more ethylenically unsaturated double bonds may be used together therewith. As the reactive monomer having two or more ethylenically unsaturated double bonds,
Examples thereof include conjugated dienes such as butadiene and isoprene, divinylbenzene, and trimethylolpropane tri (meth) acrylate.

As the dispersion stabilizer, water-soluble polymer compounds are generally used, and examples thereof include polyvinyl alcohol, polyvinylpyrrolidone, hydroxyethyl cellulose, carboxymethyl cellulose and cellulose gum. If necessary, a nonionic surfactant or anionic surfactant, which will be described later, may be used in combination with the dispersion stabilizer.

Examples of the polymerization initiator include benzoyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, peroxides such as sodium persulfate and ammonium persulfate, azobisisobutyronitrile, azobisisovaleronitrile. And other azo compounds.

Alternatively, an emulsifier and a coloring agent (A)
In the presence of a reactive monomer capable of forming the binder resin (B) by emulsion polymerization in the presence of a polymerization initiator,
There is a method of obtaining a spherical aqueous dispersion of toner particles in which a colorant (A) is included in a binder resin (B) (hereinafter, the dispersion obtained by this method will be referred to as an emulsion polymerization dispersion hereinafter). That.).

In this method, as the reactive monomer capable of forming the binder resin (B), those which can be used for obtaining the polymer used for the binder resin (B) are as described above. , Of course, either can be used. If necessary, a small amount of the reactive monomer having two or more ethylenically unsaturated double bonds may be used together therewith. Examples of the emulsifier include sodium dodecylbenzenesulfonate, sodium lauryl sulfate, anionic surfactants such as sodium dodecyldiphenyloxide disulfonate, and nonionic surfactants such as polyoxyethylene lauryl ether and polyoxyethylene ninyphenol ether. Can be mentioned.

Further, if necessary, for example, a chain transfer agent such as dodecyl mercaptan, carbon tetrachloride, thioglycolic acid, a reducing agent such as sodium acid sulfite, sodium thiosulfate, sodium metabisulfite, ethylenediaminetetraacetate, etc. A chelating agent may be used together therewith.

The reaction conditions in the suspension polymerization method and emulsion polymerization method are usually room temperature to 80 ° C. and 15 minutes to 24 hours. The amount of dispersant or emulsifier used is usually 1
It is in the range of 0.01 to 10 parts by weight per 00 parts by weight.

As another method, an organic solvent solution containing a colorant (A), a binder resin (B), and an emulsifier is phase-inversion emulsified in an aqueous medium to prepare toner particles. An organic solvent solution containing a self-water dispersible resin as a binder resin and containing it and a colorant (A) without removing the organic solvent from the aqueous dispersion or substantially using an emulsifier,
Spherical, binder resin (B) which is phase-inverted and emulsified in an aqueous medium.
The toner particles containing the colorant (A) therein are generated,
There is a method of removing an organic solvent from such an aqueous dispersion (hereinafter, the dispersion obtained by this method is referred to as a phase inversion emulsification method dispersion).

Among the above-mentioned manufacturing methods exemplified for manufacturing a toner by a wet method, a separate step such as a water washing step for separately removing the dispersion stabilizer, the emulsifier and the like is not required and the productivity is excellent. Then, it is preferable to use the aqueous dispersion obtained by the latter phase inversion emulsification method, which does not substantially use an emulsifier, as the aqueous dispersion of the toner particles (C) of the present invention.

The latter phase inversion emulsification method dispersion liquid, which does not use an emulsifier, has no charging property as compared with other wet process type toners because no emulsifier or dispersion stabilizer remains in the final toner powder. A more stable spherical dry toner can be obtained.

In this phase inversion emulsification method dispersion, an organic solvent solution of a resin (b1) in which a colorant (A) is dispersed and which can be self-dispersible by neutralization is added to water containing a neutralizing agent. Phase inversion emulsification is performed, or water containing a neutralizing agent is added to an organic solvent solution of a resin (b1) in which a colorant (A) is dispersed and which can be self-water dispersible by neutralization, to perform phase inversion emulsification. Obtained by removing the organic solvent from an aqueous dispersion obtained by dispersing the spherical self-water-dispersible resin (b2) particles encapsulating the colorant (A) in an aqueous medium. Can be done.

Alternatively, the organic solvent solution of the self-water-dispersible resin (b2) in which the colorant (A) is dispersed is added to water for phase inversion emulsification, or the colorant (A) is dispersed. The self-water-dispersible resin (b2) is a spherical self-water-dispersible resin (b2) particle containing a colorant (A), which is obtained by adding water to an organic solvent solution to carry out phase inversion emulsification. The same preparation can be performed by obtaining an aqueous dispersion liquid dispersed in a medium and removing the organic solvent from the aqueous dispersion liquid.

The resin (b1) capable of becoming self-dispersible in water by neutralization is a resin containing in its molecule a functional group capable of becoming a hydrophilic group by neutralization, and a part of these functional groups capable of becoming hydrophilic. Alternatively, it refers to a resin having the ability to form a stable aqueous dispersion without the use of an emulsifier when all are neutralized with a neutralizing agent.

In the case of anionic resins, examples of the functional group capable of becoming a hydrophilic group by neutralization in this resin include a so-called acidic group such as a carboxyl group, a phosphoric acid group and a sulfonic acid group. In the case of the mold resin, for example, a so-called basic group such as a dimethylamino group and a diethylamino group can be mentioned.

On the other hand, the self-water-dispersible resin (b2) has a salt structure in which some or all of the functional groups of the self-water-dispersible resin (b1) are neutralized by the neutralizing agent. Say resin.

Taking a carboxy group-containing anion type resin as an example of the resin (b1) which can be self-dispersible in water by neutralization, the resin (b1) can be anionic hydrophilic group by neutralization. The content of the carboxyl group is not particularly limited, but an acid value of about 40 or more is preferable because particles can be easily formed by the phase inversion emulsification method. Particularly preferably, the acid value is 50 to 150.

The reaction conditions for obtaining the resin (b1) or (b2) are generally in the temperature range of 50 to 150 ° C. under a nitrogen atmosphere. Further, since the resin (b1) and the resin (b2) are capsule type particles, they have a molecular weight at a sufficient level for the capsule wall, and usually have a weight average molecular weight of 5,000 to 200,000, preferably 10,000 to 150,000. is there.

In the latter phase inversion emulsification method dispersion which does not substantially use an emulsifier, first, an organic solvent solution of the self-water dispersible resin (b2) in which the colorant (A) is dispersed is prepared. In preparing this solution, a resin (b1) that can become self-water dispersible by neutralization is used, and a neutralizing agent is also used in combination to neutralize the resin (b1) and convert it into a resin (b2). It can be used later.

Examples of the organic solvent which 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; cellosolve. Or various ether alcohols such as carbitol; various ketones such as acetone, methyl ethyl ketone or methyl isobutyl ketone; various esters such as ethyl acetate or butyl acetate; or various ether esters such as butyl cellosolve acetate And the like. Of course, these can also be used when preparing the above-mentioned resin (B) itself.

In the preparation of the organic solvent solution, the colorant (A) and the binder resin (B), which can be self-dispersible in water by neutralization (b1) or self-dispersible resin (b2) The weight ratio of the solid content is not particularly limited, but as described above, it is preferable that the colorant (A) is 3 to 30% by weight when the total weight thereof is 100.

Further, in carrying out the present invention using the resin (b1) or the resin (b2), a binder resin other than that may be used in combination therewith, if necessary.

The neutralizing agent used in the present invention is such that the resin (b1) which can be self-water dispersible by neutralization, for example, the resin which can be anionic type or the resin which can be cationic type, can be self-water dispersible in an aqueous medium. No particular limitation is imposed on the kind as long as it exhibits the above hydrophilicity, and a compound which easily forms a cation ion or anion ion in water can be used.

Specific examples of effective neutralizing agents for anionic resins include, for example, sodium silicate, potassium silicate, sodium hydroxide, potassium hydroxide, lithium hydroxide, dibasic sodium phosphate, and tribasic phosphoric acid. sodium,
Inorganic alkali agents such as dibasic ammonium phosphate, tribasic ammonium phosphate, sodium metasilicate, sodium carbonate, and ammonia, mono-, di-, or trimethylamine, mono-, di-, or triethylamine, mono-, or diisopropylamine, n-butylamine, Organic amine compounds such as mono-, di- or triethanolamine, mono-, di- or triisopropanolamine, ethyleneimine, ethylenediimine and the like can be mentioned.

Specific examples of effective neutralizing agents for cationic resins include organic acids such as formic acid, acetic acid and propionic acid, and inorganic acids such as hydrochloric acid, sulfuric acid, sulfonic acid and phosphoric acid. .

The non-volatile content of the organic solvent solution used for phase inversion emulsification is not particularly limited, but is usually 10 to 70% by weight.

In the present invention, in addition to the above-mentioned phase inversion emulsification method dispersion liquid, a water-insoluble or water-non-swelling resin (b1) containing a colorant (A) and capable of becoming self-water dispersible by neutralization. Toner particles (C) are dispersed in an aqueous medium containing a salt of a neutralizing agent used for neutralizing the resin (b1) and a neutralizing agent having an opposite polarity, It can also be used.

An aqueous dispersion of toner particles also containing this salt is
A neutralizing agent having a polarity opposite to that of the neutralizing agent used for neutralizing the resin (b1) to convert it into the resin (b2) is added to the phase inversion emulsification method dispersion liquid from which the above organic solvent has been removed. Resin (b
It is easily obtained by converting 2) into the resin (b1) again, forming a salt by the neutralization reaction of the neutralizing agents, and dispersing the resin (b1) in the aqueous medium by the salt. .

By the suspension polymerization method, emulsion polymerization method and phase inversion emulsification method described above, it is possible to obtain an aqueous dispersion of substantially spherical toner particles (C) with relative ease.

In the present invention, the above-mentioned toner particle aqueous dispersion is
The water-insoluble or water-nonswellable fine particles (F) of the resin (D) or the self-water-dispersible resin (E) which can become self-water-dispersible by neutralization were mixed and dispersed as an aqueous dispersion or powder. After that, the aqueous medium is removed and dried.

The fine particles (F) used in the present invention thus consist of the resin (D) or the self-water dispersible resin (E) which can be self-water dispersible by neutralization. This fine particle (F)
Must have a smaller average particle size than the toner particles (C) in the toner particle aqueous dispersion. The average particle diameter is usually 0.01 to 8 μm, preferably 0.05.
Those having a particle size of ˜5 μm are suitable.

As the fine particles (F), it is preferable to use fine particles having a glass transition temperature (Tg) and a Tg higher than that of the binder resin (B) in the toner particles (C).

When the toner particles (C) used in the present invention are spherical particles, since the particles have excellent fluidity, the fine particles (F) are also spherical in the sense that the characteristics are not impaired. Is preferably selected.

Further, since the fine particles (F) are mixed and dispersed in the aqueous dispersion of toner particles, they should not dissolve or swell in the aqueous medium. Fine particles (F)
Since the toner forms the outermost contour of the toner particles (C), it is preferable to have as a basic characteristic that the surface of the photoreceptor is not scratched and that it has sufficient mechanical strength so as not to be destroyed in the developing machine.

Specifically, the resin (D) or the self-water-dispersible resin (E) having a Shore D hardness of 45 or more, particularly 45 to 100, which can be self-water-dispersible by neutralization, is a hardness standard. The fine particles) are preferably used in the present invention.

The resin (D) or the self-water dispersible resin (E) which can become self-water dispersible by neutralization in the fine particles (F) is defined as the same as the resins (b1) and (b2) described above. It

The fine particles (F) and the salt used in combination therewith may be added as they are to the aqueous dispersion of toner particles, but the aqueous solution of the fine particles (F) may optionally contain a salt. As a dispersion liquid, it can be added to the toner particle aqueous dispersion liquid. Compared to adding fine particles (F) as powder, by using an aqueous dispersion of fine particles (F), it is possible to easily and stably disperse the toner particles in the aqueous dispersion of toner particles in a short time. .

In this case, the fine particles (F) are dispersed in the dispersion by means such as normal stirring or ultrasonic wave. By such a treatment, the fine particles (F) are adsorbed on the surface of the toner particles (C), and a good aqueous dispersion liquid having no problem such as sedimentation or aggregation can be obtained.

When the fine particles (F) are composed of the resin (D) which can be self-dispersible in water by neutralization, the neutralizing agent used for neutralizing the resin (D) and the polarity opposite to that of the neutralizing agent. It is also possible to use a salt composed of a solvating agent together and add them to the toner particle aqueous dispersion.

As the resin (D) or the self-water dispersible resin (E) which can be self-water dispersible by neutralization, the same ones as described above can be used, but as the resin further improving the self-water dispersibility. Further, those containing a hydrophilic block having an ether bond such as an ethylene oxide polymer unit or a copolymer unit of ethylene oxide and other alkylene oxide in the resin skeleton can also be used.

Specific examples of the resin (D) or the self-water-dispersible resin (E) capable of self-water dispersion by neutralization in the fine particles (F) used in the present invention include a main chain of a polymer resin and / or Epoxy resin, polyurethane resin, polyamide resin, styrene containing a hydrophilic group such as hydroxyl group, oxazoline group, cyclocarbonate group, ether bond, phosphoric acid ester group, carboxyl group, sulfonic acid group or amino group in the side chain. Examples thereof include resin, acrylic resin, alkyd resin, polyester resin and the like. The molecular weight of this resin (D) or (E) is 3,000 to 100,000, preferably, in the case of an acrylic type, in order to obtain fine particles (F) having sufficient mechanical strength.
Those having a number average molecular weight of 5,000 to 30,000 are preferable.

The fine particles (F) used in the present invention are not limited to using only one type, and a plurality of types may be used in combination.

The resin (E) is the resin (D) as described above.
A resin having a group capable of becoming hydrophilic by neutralization is selected from the above, and a part or all of the group is neutralized with a neutralizing agent, whereby the resin can be easily obtained.

The fine particles (F) are usually the glass transition temperature (Tg) of the binder resin (B) in the particles (C).
Although fine particles having a higher Tg are used, more specifically, fine particles (F1) having a Tg of 50 ° C. or higher are preferably used. Therefore, as the resin (D) and the resin (E), it is preferable to use the resin (d1) or the resin (e1) having Tg of 50 ° C. or higher.

For the aqueous dispersion of the fine particles (F), a method for obtaining the phase inversion emulsification method dispersion can be adopted, and appropriately adjusted so that the average particle diameter becomes smaller than that of the toner particles (C). Can be easily obtained.

The method for producing these fine particles (F) is not particularly limited. For example, in the case of an aqueous dispersion of self-water-dispersible polyurethane resin fine particles, a diol and a diisocyanate, a diol containing a polyethylene oxide polymer unit, and a sulfophthalic acid are used. A salt, dialkanol monoalkanoic acid or the like is reacted in an organic solvent with a compound containing a hydrophilic group or a group capable of becoming hydrophilic by anionic neutralization as an essential component, and part or all of the carboxyl group is A method of removing the organic solvent by neutralizing with a base as described above, dispersing in an aqueous medium, and the like. Of course, a diol and a diisocyanate may be preliminarily reacted to obtain a terminal isocyanate prepolymer, which may be chain-extended with a dialkanol monoalkanoic acid, or a diol, a diisocyanate, and a dialkanol monoalkanoic acid may be preliminarily reacted. It is also possible to obtain a terminal isocyanate prepolymer and chain extend it with another diol or diamine. Further, if necessary, water may be removed and dried to obtain a fine particle (F) powder.

Examples of the diol include polymer diols such as polyester diol, polyether diol, polyether ester diol, polyamide diol, polycarbonate diol, polycaprolactone diol, ethylene glycol, propylene glycol, diethylene glycol, butane diol, hexane diol, etc. Is mentioned.

Examples of the diisocyanate include tolylene diisocyanate (TDI), hexamethylene diisocyanate (HMDI), diphenylmethane diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate and hydrogenated diphenylmethane diisocyanate.

For chain extension, polyamines such as hydrazine, ethylenediamine, hexamethylenediamine, cyclohexanediamine, isophoronediamine and diphenylmethanediamine, and hydroxylamine such as diethanolamine can be used.

In obtaining the above polyurethane resin, if necessary, a monoalcohol such as methanol, ethanol, isopropyl alcohol, monoisocyanate, glycerin, trimethylolpropane (TM) is used.
P), a polyhydric alcohol having a valence of 3 or more such as pentaerythritol, a TDI-TMP adduct, a polyisocyanate having a valence of 3 or more such as an HMDI isocyanurate compound can be used in combination.

In the reaction, for example, in the presence of a catalyst, the active hydrogen atom: isocyanate group has an equivalent ratio of 0.7: 1.0 to.
1.0 to 0.7, 10 to 100 ° C., 30
It can be performed in the range of minutes to 24 hours.

When an aqueous dispersion of styrene resin fine particles or acrylic resin fine particles is obtained, the method exemplified for the phase inversion emulsification method dispersion without using an emulsifier in the method of preparing an aqueous dispersion of toner particles is also the same. It can be adopted similarly.

As in the case of the aqueous dispersion of toner particles, a neutralizing agent having a polarity opposite to that of the neutralizing agent used is added to the phase inversion emulsion dispersion containing the fine particles (F) to perform reverse neutralization. By doing so, the resin in the fine particles (F) can be converted from the resin (E) to the resin (D) and used as an aqueous dispersion containing a salt.

The amount of the fine particles (F) used in the present invention is
The solid content of the toner particles (C) is 100 parts by weight based on 0.
It can be used in an amount of 01 to 10 parts by weight, but more preferably 0.03 to 3 parts by weight gives good results. Within this range, the sufficient effect of the present invention can be obtained,
In addition, the characteristics of the toner particles (C) themselves are less likely to be impaired.

When two or more different types of fine particles (F) are used, the order and timing of addition of the two or more types of fine particle (F) powder to the dispersion liquid are not particularly limited. May be added to the dispersion at the same time, or may be added individually thereto in sequence. Furthermore, fine particles (F)
It is also possible to use water-insoluble or water-swellable inorganic fine particles in combination.

Further, water and, if necessary, an organic solvent used in combination are removed from this dispersion and dried to obtain a dry toner in which fine particle (F) powder is adhered and contained on the surface of toner particle (C). .

In removing and drying a dispersion medium such as an aqueous dispersion of fine particles (F) and an aqueous dispersion of toner particles, any known method can be employed. For example, water and an organic solvent used in combination as necessary. Examples of the method for removing the dispersion medium such as: include decantation and filtration with a filter, and examples of the drying method include hot air drying and freeze drying. Of course, with a spray dryer,
The toner powder may be directly obtained from water alone or an aqueous dispersion containing water and an organic solvent.

The organic solvent and water may be simultaneously removed from these dispersions, but the organic solvent is usually removed first. When removing only the organic solvent from the dispersion liquid, for example, distillation is common, and it can be removed at a low temperature, and the particles (C) and the particles (F) do not melt or soften, and thus vacuum distillation is performed. Is preferably performed.

The drying temperature for removing the dispersion medium such as water and the organic solvent optionally used in combination from the aqueous dispersion of toner particles is a temperature at which the particles (C) are not softened.
The drying temperature at the time of removing water and the organic solvent optionally used in combination from the fine particle (F) aqueous dispersion is a temperature at which the fine particles (F) do not soften, and the toner particles (C) and the fine particles (F In the case of an aqueous dispersion containing a), it is preferable to carry out at a temperature at which neither the fine particles (F) nor the particles (C) are softened.

That is, in the method for producing a toner of the present invention, since it is necessary that the fine particles (F) be in the form of particles and adhere to the surface of the particles (C), the particles having a higher softening point than the particles (C). (E1) is used, and the drying temperature is the particle (C).
It is preferable that the temperature is lower than the softening point. Further, for example, the resin (B1) is softened by combining the particles (C) and the fine particles (F) so that the resin (d1) or the resin (e1)> resin (B1) is obtained at the glass transition temperature. Most preferably, the removal and drying of the aqueous medium is carried out at a temperature below the point.

In the above operation, the resins (b1), (d
After removing the organic solvent from the aqueous dispersion containing the particles (C) and the fine particles (F) formed of the resins (b2) and (e1), which is formed by neutralizing 1) with a neutralizing agent, phase inversion is performed. The resin (E) in the particles (C) is obtained by adding a neutralizing agent having a polarity opposite to that of the neutralizing agent used for the emulsification or water containing the same to carry out reverse neutralization.
Can also be converted to a resin (D) to form a salt, and then water can be removed and dried. This is preferable because odor is not generated and the electric characteristics of the obtained toner do not fluctuate.

The electrophotographic 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, or as a two-component developer in combination with a carrier. Good characteristics can be obtained as a developer.

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

[0084]

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 [manufactured by 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 0.25 g was further 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 with a kneader "Eiger M-250VSE-EXJ" (kneader manufactured by Eiger, USA) for 1 hour, 5.6 g of triethylamine was added, and water was added dropwise while stirring at 350 rpm using a three-one motor. Phase inversion emulsification was performed to obtain an aqueous dispersion of toner particles containing a colorant and made of 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.

On the other hand, in order to prepare an aqueous dispersion of fine particles of an organic polymer, 293 g of polytetramethylene glycol "Unisafe PT-200" (manufactured by NOF CORPORATION) and isophorone diisocyanate 77 having a number average molecular weight of 2000.
g and were charged in a flask and kept at 120 ° C. for 30 minutes while stirring under a nitrogen blanket, and then tin octenoate 0.05
g was added and the reaction was continued for another hour. The temperature was lowered to 80 ° C., 210 g of methyl ethyl ketone and 20 g of dimethylolpropionic acid were added, the reaction was continued at 75 ° C. for 5 hours, and a polyurethane resin capable of becoming self-water dispersible by neutralization was obtained. In addition, "DN-980S" [manufactured by Dainippon Ink and Chemicals, Inc.]. Polymethyl Isocyanate Consisting of Trimethylolpropane-Tolylene Diisocyanate Adduct]
90 g was added to prepare a mixed solution.

Separately, triethylamine 2.3 was added to 200 g of water.
An aqueous solution having g dissolved therein is prepared, and 130 g of the above mixed solution is gradually added while stirring to perform phase inversion emulsification (here,
The polyurethane resin that can become self-water dispersible by neutralization has become a self-water dispersible polyurethane resin. ), An aqueous dispersion was obtained. Further, a mixed solution of 14 g of diethylenetriamine and 100 g of water was added to and mixed with the aqueous dispersion. Then, methyl ethyl ketone was removed by distillation under reduced pressure with an aspirator while heating at 70 ° C., to obtain an aqueous dispersion in which polyurethane resin fine particles were stably dispersed in water.

The fine particles have an average particle size of 0.5 micron, a Shore D hardness of 45 to 100, and a T
It was confirmed that the g was 50 ° C. or higher, and the Tg thereof was higher than that of the binder resin of the toner particles, and the particles were substantially spherical organic polymer fine particles. The fine particles were water-insoluble and water-swellable.

To the above-mentioned toner particle aqueous dispersion, an aqueous dispersion of the organic polymer fine particles was added in an amount corresponding to 0.5% by weight in terms of fine particles, and a TK homomixer [Tokushu Kika Co., Ltd.
Manufactured] at 1000 rpm for 10 minutes.

Then, the organic solvent is removed by vacuum distillation so that the resin and the fine particles of the organic polymer of the toner particles are not softened, and the spray dryer is sprayed at a spraying temperature of 60 ° C., which is lower than the softening temperature of both the resin and the fine particles of the toner particles. And dried to obtain a dry toner. It was confirmed with an electron microscope that the polyurethane-based resin fine particles, which can be self-water dispersible by neutralization, are attached to the surface of the toner particles composed of styrene-based resin spherical particles that can be self-water dispersible by neutralization. This toner powder was excellent in fluidity, and no aggregation of particles was observed.

Separately, the above-mentioned toner particle aqueous dispersion containing fine particles of polyurethane resin was filtered to obtain toner particles, which were dried by a freeze dryer for about 24 hours. The obtained toner did not aggregate, had good fluidity, and was suitable for practical use.

Each of the obtained dry toners had an average particle size of 65
When a developer was prepared by mixing and stirring 3 parts by weight with 100 parts by weight of a ferrite carrier of μm, and a copying test was carried out with a commercially available electronic copying machine, both toners were
With almost no adhesion or accumulation on the photoconductor drum, 2000
A clear image faithful to 0 or more originals was obtained.

Comparative Example 1 A dry toner was prepared without using the polyurethane resin fine particles used in Example 1.
That is, toner particles were added to the aqueous dispersion of toner particles shown in Example 1 without adding an aqueous dispersion of polyurethane resin fine particles obtained by phase inversion emulsification of an organic solvent solution of a self-water dispersible resin in water. The organic solvent was removed from the aqueous dispersion by vacuum distillation so as not to soften.

This toner particle aqueous dispersion was dried with a spray dryer having a spraying temperature of 60 ° C. in the same manner as in Example 1 to obtain a dry toner. In the obtained toner, the toner particles were locally aggregated, and the fluidity was poor and the toner could not be put to practical use. An attempt was made to dry with a spray dryer at a temperature lower than that described above, but it did not dry. Attempts were made to dry with a spray dryer at a temperature higher than the above, but the aggregation of toner particles increased and the fluidity also deteriorated.

Separately, the above toner particle aqueous dispersion was filtered to obtain toner particles, which were dried with a freeze dryer. The obtained toner did not aggregate and had good fluidity and was practically usable, but this drying required about 36 hours.

Example 2 A mixed solution of 200 g of styrene, 176 g of methyl methacrylate, 24 g of methacrylic acid and 8 g of "perbutyl O" was prepared.

60 g of this mixture and 4 of methyl ethyl ketone
00g was charged into a flask, the temperature was raised to 75 ° C with stirring under a nitrogen blanket, and the temperature was maintained for 30 minutes. The remaining mixed solution was added dropwise over 1.5 hours.
The reaction was continued by holding for a period of time to obtain an organic solvent solution of styrene-acrylic resin which can be self-dispersible in water by neutralization.

This styrene-acrylic resin solution 100
3.5 g of triethylamine was added to g (here, the styrene-acrylic resin that can be self-water dispersible by neutralization became a self-water dispersible styrene-acrylic resin), and water was added thereto with stirring. After gradually adding 200 g to obtain an aqueous dispersion by phase inversion emulsification, the organic solvent was removed by vacuum distillation from the styrene-acrylic resin fine particles of water-dispersible styrene / acrylic resin so as not to soften, and the pH was adjusted to 6 0.01 N aqueous hydrochloric acid solution was added until the mixture became styrene-acrylic resin (the self-water-dispersible styrene-acrylic resin became a styrene-acrylic resin that can be self-water-dispersible by neutralization). Acrylic organic polymer fine particles stably dispersed in water containing salt were obtained.

The fine particles have an average particle size of 2.0 μm, a Shore D hardness of 45 to 100, and a T
It was confirmed that the g was 50 ° C. or higher, and the Tg thereof was higher than that of the binder resin of the toner particles, and the particles were substantially spherical organic polymer fine particles. The fine particles were water-insoluble and water-swellable.

Then, in the same manner as in Example 1, an aqueous dispersion of toner particles was prepared in which toner particles were dispersed in an aqueous medium. To this toner particle aqueous dispersion, an aqueous dispersion of the organic polymer fine particles was added in an amount equivalent to 1.0% by weight in terms of fine particles, and the mixture was stirred at 350 rpm for 20 minutes while applying ultrasonic waves to carry out dispersion stirring treatment. .

Next, the organic solvent was removed by vacuum distillation so that the resin and the fine particles of the organic polymer of the toner particles were not softened, and the spray dryer was sprayed at a spraying temperature of 60 ° C., which is lower than both the softening temperature of the resin and the fine particles of the toner particles. And dried to obtain a dry toner. It was confirmed with an electron microscope that the styrene-acrylic resin fine particles that can be self-water dispersible by neutralization are attached to the surface of the toner particles composed of styrene resin spherical particles that can be self-water dispersible by neutralization. This toner powder was excellent in fluidity, and no aggregation of particles was observed.

Separately, the above toner particle aqueous dispersion containing styrene-acrylic resin fine particles was filtered to obtain toner particles, which were dried by a freeze dryer for about 24 hours. The obtained toner did not aggregate, had good fluidity, and was suitable for practical use.

Each of the obtained dry toners had an average particle size of 65
When a developer was prepared by mixing and stirring 3 parts by weight with 100 parts by weight of a ferrite carrier of μm, and a copying test was carried out with a commercially available electronic copying machine, both toners were
With almost no adhesion or accumulation on the photoconductor drum, 2000
A clear image faithful to 0 or more originals was obtained. 60 ° C
It was dried with a spray dryer having a spraying temperature of 1 to obtain a dry toner. This toner had excellent fluidity, and no aggregation of particles was observed.

(Example 3) 210 g of styrene, 45 g of butyl acrylate, 42 g of methyl methacrylate, 3 g of ethylene glycol monomethacrylate, 15 g of carbon black "MA-100", VISCOL 550P
[Sanyo Kasei Co., Ltd. polypropylene wax] 3 g, Bontron S-34 [Orient Chemical Co., Ltd. azo type metal-containing dye-containing charge control agent] 5 g, azobisisobutyronitrile 6 g, dodecyl mercaptan 3 g After dispersing with a sonic homogenizer, 1500 g of water was added and dispersed and suspended. Toner particles in which suspension polymerization is carried out at 80 ° C. for 5 hours in a nitrogen stream, filtration and washing are repeated, and toner particles made of a styrene resin containing a colorant and also containing a wax and a charge control agent are dispersed in water. An aqueous dispersion was prepared. The toner particles were toner particles having an average particle size of 8 microns as measured by a Coulter counter. Further, it was confirmed by observation with an electron microscope that the toner particles were truly spherical.

Example 2 was prepared using this aqueous dispersion of toner particles.
The water dispersion of styrene-acrylic resin fine particles containing triethylamine-hydrochloride, which is 2.0 micron and which can be self-water-dispersible by neutralization, in an amount of 0.
Add 3 wt% equivalent amount and 1000 with TK homomixer
Dispersion and mixing treatment was performed at rpm for 10 minutes.

Then, the organic solvent is removed by vacuum distillation so that the resin and the fine particles of the organic polymer of the toner particles are not softened, and a spray dryer having a spraying temperature of 60 ° C. which is lower than the softening temperature of both the resin and the fine particles of the toner particles. And dried to obtain a dry toner. It was confirmed by an electron microscope that the styrene-acrylic resin fine particles which can be self-dispersible in water by neutralization are attached to the surface of the toner particles composed of styrene resin spherical particles. This toner powder was excellent in fluidity, and no aggregation of particles was observed.

Separately, the above toner particle aqueous dispersion containing styrene-acrylic resin fine particles was filtered to obtain toner particles, which were dried for about 24 hours by a freeze dryer. The obtained toner did not aggregate, had good fluidity, and was suitable for practical use.

Each of the obtained dry toners had an average particle size of 65
When a developer was prepared by mixing and stirring 3 parts by weight with 100 parts by weight of a ferrite carrier of μm, and a copying test was carried out with a commercially available electronic copying machine, both toners were
With almost no adhesion or accumulation on the photoconductor drum, 2000
A clear image faithful to 0 or more originals was obtained. 60 ° C
It was dried with a spray dryer having a spraying temperature of 1 to obtain a dry toner. This toner had excellent fluidity, and no aggregation of particles was observed.

Comparative Example 2 A dry toner was prepared without using the styrene resin fine particles used in Example 3. That is, with respect to the toner particle aqueous dispersion shown in Example 3, a neutralizing agent was added to an organic solvent solution of a styrene-acrylic resin that can become self-water dispersible by neutralization, and phase inversion emulsification in water was performed.
Obtaining an aqueous dispersion of fine particles, removing the solvent so that the fine particles do not soften, and then adding a neutralizing agent having the opposite polarity to that described above, containing a salt, styrene that can be self-water dispersible by neutralization An aqueous dispersion of toner particles was dried with a spray dryer having a spraying temperature of 60 ° C. in the same manner as in Example 3 without adding an aqueous dispersion of acrylic resin particles to obtain a dry toner.

The obtained toner had toner particles locally agglomerated and had poor fluidity and could not be put to practical use. An attempt was made to dry with a spray dryer at a temperature lower than that described above, but it did not dry. Attempts were made to dry with a spray dryer at a temperature higher than the above, but the aggregation of toner particles increased and the fluidity also deteriorated.

Separately, the aqueous dispersion of toner particles was filtered to obtain toner particles, which were dried with a freeze dryer. The obtained toner did not aggregate and had good fluidity and was practically usable, but this drying required about 36 hours.

[0115]

INDUSTRIAL APPLICABILITY According to the present invention, the toner particles dispersed in the aqueous medium produced by the wet process toner are fine particles of a self-water-dispersible resin smaller than that, or water-insoluble or water-insoluble of the self-water-dispersible resin by neutralization. Swellable fine particles and salts are added, and the aqueous medium is removed from the obtained aqueous dispersion and dried to obtain a dry toner in which the fine particles adhere to the surface of the toner particles, so that aggregation between toner particles in the drying step is prevented. A particularly remarkable effect that it can be effectively prevented and that the time for removing the aqueous medium can be greatly shortened is exhibited.

Claims (8)

[Claims] 1. A toner particle aqueous dispersion in which toner particles (C) comprising a colorant (A) and a binder resin (B) are dispersed in an aqueous medium, and the average particle diameter is smaller than the particle. Water-insoluble or water-swellable fine particles (F) of the resin (D) or the self-water-dispersible resin (E) which may become self-water-dispersible by addition
The method for producing toner particles, wherein the fine particles (F) are attached to the surfaces of the particles (C), characterized in that the aqueous medium is removed and dried after mixing and dispersing. 2. A toner particle aqueous dispersion comprising toner particles (C) comprising a colorant (A) and a binder resin (B) dispersed in an aqueous medium, wherein the average particle size is smaller than the particle size. The fine particles (F) are characterized in that the water-insoluble or water-swellable fine particles (F) of the water-dispersible resin (E) are mixed and dispersed, and then the aqueous medium is removed and dried. (C) A method for producing toner particles adhered to the surface. 3. A toner particle aqueous dispersion in which toner particles (C) comprising a colorant (A) and a binder resin (B) are dispersed in an aqueous medium, and the average particle size is smaller than the particle. Water-insoluble or water-swellable fine particles (F) of the resin (D) which may be self-water dispersible by the addition, and a neutralizing agent used for neutralizing the resin (D) and a neutralizing agent having an opposite polarity thereto A method for producing toner particles, wherein fine particles (F) are attached to the surfaces of the particles (C), characterized by mixing and dispersing an aqueous dispersion liquid containing a salt consisting of 4. A self-water-dispersible resin in which the fine particles (F) have a Tg higher than the glass transition temperature (Tg) of the resin (B) contained in the particles (C) and have an average particle diameter smaller than that of the particles. 2. The water-insoluble or water-swellable fine particles of
The manufacturing method according to 2 or 3. 5. Particles (C) are toner particles comprising a colorant (A) and a binder resin (B1) having a glass transition temperature of 50 to 100 ° C., and the fine particles (F) are average particles. Fine particles (F1) having a glass transition temperature of 50 ° C. or higher, which are smaller in diameter than the particles, are used, and their glass transition temperatures are
The production method according to claim 1, 2 or 3, wherein they are used in combination such that F1> B1, and the aqueous medium is removed and dried at a temperature lower than the softening point of the resin (B1) in the particles (C). 6. The method according to claim 1, 2 or 3, wherein 0.01 to 10 parts by weight of the fine particles (F) are used per 100 parts by weight of the particles (C). 7. The particles (C) are toner particles having an average particle size of 4 to 12 μm, and the fine particles (F) have an average particle size of 0.
The method according to claim 1, 2 or 3, wherein the particles are water-insoluble or water-swellable fine particles having a size of 01 to 8 µm. 8. The method according to claim 1, 2 or 3, wherein the fine particles (F) are fine resin particles selected from the group consisting of polyurethane resins, styrene resins and acrylic resins.