JP2011133534A - Process for producing toner for electrophotography - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process for producing a toner for electrophotography which can improve all of the storage stability, the environmental stability of a charge amount and scattability of the toner, and a process for producing a toner for electrophotography which can improve storage stability and transferability. <P>SOLUTION: The process for producing the toner for electrophotography includes: a step 1 of adding an aggregating agent to a resin particle dispersion so as to attain an aggregating agent concentration Ea (wt.%), to thereby obtain an aggregated particle dispersion; a step 2 of adding a resin microparticle dispersion to the aggregated particle dispersion obtained in the step 1, to thereby obtain a dispersion of resin microparticle-deposited aggregated particles having an aggregating agent concentration Eb (wt.%) satisfying 0.60≤Eb/Ea<1; a step 3 of modifying the aggregating agent concentration of the dispersion of the resin microparticle-deposited aggregated particles obtained in the step 2, to an aggregating agent concentration Ec (wt.%) satisfying 0.005≤Ec/Ea≤0.30; and a step 4 of heating the resin microparticle-deposited aggregated particles in the dispersion of the resin microparticle-deposited aggregated particles having the aggregating agent concentration Ec obtaind in the step 3 at a temperature falling within a range between the glass transition point Tg(°C) and Tg+20 (°C) inclusive of the resin microparticles in the resin microparticle dispersion, to thereby coalesce the aggregated particles. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for producing an electrophotographic toner used in an electrophotographic method, an electrostatic recording method, an electrostatic printing method, and the like, and an electrophotographic toner obtained by the production method.

In the field of electrophotographic toner, development of a toner having improved storage stability, environmental stability, transferability, and the like is required with the development of an electrophotographic system.
Patent Document 1 discloses a method of hydrophobizing a toner surface by encapsulating without adding a metal salt when a chemical toner having a core-shell structure is made to adhere to the core particles. Has been.
In Patent Document 2, when producing a chemical toner, inorganic fine particles are adhered to the surface after producing aggregated particles, and then coalesced to uniformly adhere the inorganic fine particles to the surface, improving transferability and storage stability. Possible methods are disclosed.
In addition, the chemical toner does not have a mechanical share such as kneading, resulting in poor dispersion and a deterioration in storage stability. Therefore, Patent Document 3 discloses a method of using two or more kinds of metal salts having different valences as an aggregating agent when producing a chemical toner from the viewpoint of achieving both storage stability and environmental stability of the toner. .
Patent Document 4 discloses a toner manufacturing method in which the concentration of the aggregating agent is changed at the time of thermal fusion at the time of preparation of the chemical toner from the viewpoint of chargeability. Further, Patent Document 5 discloses from the viewpoint of transferability. In addition, a toner manufacturing method using a divalent or higher flocculating agent at the time of preparation of a chemical toner is disclosed.

JP 2008-268565 A JP-A-10-207125 JP 2003-66646 A JP 2000-131882 A JP 2001-305789 A

However, all of the techniques described in Patent Documents 1 to 5 satisfy the storage stability of the toner, the environmental stability of the charge amount, and the low scattering property, and the excellent storage stability of the toner. From the viewpoint of achieving both transferability and transferability, it is still not sufficient.
The present invention relates to a method for producing an electrophotographic toner having at least improved storage stability.
The present invention also relates to a method for producing a toner for electrophotography in which the storage stability of the toner, the environmental stability of the charge amount, and the low scattering property are all improved.
Furthermore, the present invention relates to a method for producing an electrophotographic toner in which both the storage stability and transferability of the toner are improved.

The present invention
[1] (1) A flocculant is added to the resin particle dispersion so that the flocculant concentration is Ea (% by weight), and the resin particles in the resin particle dispersion are agglomerated to obtain an agglomerated particle dispersion. Step 1,
(2) Step 2 of adding a resin fine particle dispersion to the aggregated particle dispersion obtained in Step 1 to obtain a resin fine particle-attached aggregated particle dispersion having a coagulant concentration Eb satisfying the following formula 1:
0.60 ≦ Eb / Ea <1 (1)
(3) Step 3 of adjusting the coagulant concentration of the dispersion of the resin fine particle-adhered aggregated particles obtained in Step 2 to a coagulant concentration Ec satisfying the following formula 2, and 0.005 ≦ Ec / Ea ≦ 0.30 2)
(4) The resin fine particle adhered aggregated particles in the dispersion of the resin fine particle adhered aggregated particles having the coagulant concentration Ec obtained in the step 3 are equal to or higher than the glass transition point Tg (° C.) of the resin fine particles in the resin fine particle dispersion. And (4) heating and coalescing at a temperature of (Tg + 20) ° C. or lower,
A method for producing an electrophotographic toner comprising:

[2] The flocculant concentration Ec in step 3 is expressed by the formula 0.08 <Ec / Ea ≦ 0.30 (2-1)
The method for producing an electrophotographic toner according to the above [1] satisfying the above, and [3] the flocculant concentration Ec in the step 3 is expressed by the formula 0.005 ≦ Ec / Ea ≦ 0.08 (2-2)
The method for producing an electrophotographic toner according to [1], wherein
About.

According to the present invention, it is possible to provide a method for producing an electrophotographic toner having at least improved storage stability of the toner.
In addition, according to the present invention, it is possible to provide a method for producing an electrophotographic toner in which the storage stability of the toner, the environmental stability of the charge amount, and the low scattering property are all improved.
Furthermore, the present invention can provide a method for producing an electrophotographic toner with improved storage stability and transferability.

<Method for producing electrophotographic toner>
In the method for producing an electrophotographic toner of the present invention, (1) a flocculant is added to a resin particle dispersion so as to have a flocculant concentration Ea (% by weight), and the resin particles in the resin particle dispersion are removed. Step 1 for obtaining an aggregated particle dispersion by agglomeration, (2) Addition of resin fine particle dispersion to the aggregated particle dispersion obtained in Step 1, and adhesion of resin fine particles with a coagulant concentration Eb satisfying the following formula 1 Step 2 for obtaining a dispersion of particles,
0.60 ≦ Eb / Ea <1 (1)
(3) Step 3 of adjusting the coagulant concentration of the dispersion of the resin fine particle-adhered aggregated particles obtained in Step 2 to a coagulant concentration Ec satisfying the following formula 2, and 0.005 ≦ Ec / Ea ≦ 0.30 2)
(4) The resin fine particle adhered aggregated particles in the dispersion of the resin fine particle adhered aggregated particles having the coagulant concentration Ec obtained in the step 3 are equal to or higher than the glass transition point Tg (° C.) of the resin fine particles in the resin fine particle dispersion. And (Tg + 20) Step 4 of heating and coalescing at a temperature not higher than (Tg + 20) ° C.

  In the present invention, in the production of a chemical toner, after adding a resin fine particle dispersion to an aggregated particle dispersion having a specific coagulant concentration to obtain a dispersion of resin fine particle-attached aggregated particles, the concentration of the coagulant is further reduced. Surprisingly, the storage stability of the obtained toner has been improved, and furthermore, the environmental stability of the charge amount of the toner, the low scattering property, the transferability, etc. have been improved.

  In particular, since a chemical toner manufactured using an emulsion aggregation method is manufactured in an aqueous system, the hydrophilic group of the binder resin is easily oriented on the surface of the toner particles and is easily hydrophilized. In addition, since the emulsion aggregation method usually undergoes a step of coalescing the aggregated particles, the temperature in the system is maintained at a temperature higher than the glass transition point of the resin in order to sufficiently fuse the aggregated particle surface. The molecular chain of the binder resin is easy to move, the hydrophilic groups are more easily oriented on the surface of the obtained toner particles, the environmental stability of the charge amount is deteriorated, the toner is scattered, the transferability, etc. The performance of is reduced. On the other hand, if the coalescence temperature is lowered in order to solve the above-mentioned problem, the storage stability of the toner which can be insufficiently fused is inferior. However, in the present invention, after preparing the resin fine particle-attached aggregated particle dispersion with a specific flocculant concentration, the specific temperature is reduced by reducing the specific flocculant concentration to a specific flocculant concentration. In addition, the storage stability of the toner obtained unexpectedly can be improved.

[Step 1]
Step 1 is a step of adding an aggregating agent to the resin particle dispersion so as to have an aggregating agent concentration Ea (wt%), and aggregating the resin particles in the resin particle dispersion to obtain an aggregated particle dispersion. is there.

(Resin particle dispersion)
Examples of the resin constituting the resin particles in the resin particle dispersion include known resins used for toners, such as polyester, styrene acrylic copolymer, epoxy, polycarbonate, polyurethane, etc., but the storage stability of the toner, From the viewpoint of fixability and durability, it is preferable that polyester is contained. The content of the polyester is preferably 60% by weight or more, more preferably 70% by weight or more, still more preferably 80% by weight or more, substantially 100% from the viewpoint of storage stability, fixing property and durability of the toner. It is still more preferable that it is weight%.

The raw material monomer of the polyester is not particularly limited, and a known alcohol component and a known carboxylic acid component such as carboxylic acid, carboxylic acid anhydride, or carboxylic acid ester are used.
Examples of the carboxylic acid include dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, fumaric acid, maleic acid, adipic acid, and succinic acid, alkyl groups having 1 to 20 carbon atoms such as dodecenyl succinic acid, octenyl succinic acid, and 2 to 2 carbon atoms. Divalent carboxylic acids such as succinic acid substituted with 20 alkenyl groups, trivalent or higher polyvalent carboxylic acids such as trimellitic acid and pyromellitic acid, anhydrides of these acids, and alkyls of these acids (carbon Formulas 1-3) Esters and the like can be mentioned.
These carboxylic acid components may be used in combination of two or more.

  Further, as the alcohol component, specifically, bisphenol A such as polyoxypropylene-2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene-2,2-bis (4-hydroxyphenyl) propane, and the like. Alkylene (2 to 3 carbon atoms) oxide (average added mole number 1 to 16) adduct, hydrogenated bisphenol A, ethylene glycol, propylene glycol, neopentyl glycol, 1,4-butanediol, 1,3-butanediol, Examples include 1,6-hexanediol, glycerin, pentaerythritol, trimethylolpropane, sorbitol, or an alkylene (2 to 4 carbon) oxide (average added mole number 1 to 16) adduct thereof. You may use the said alcohol in combination of 2 or more type.

The polyester can be produced, for example, by polycondensing an alcohol component and a carboxylic acid component in an inert gas atmosphere at a temperature of about 180 to 250 ° C., if necessary, using an esterification catalyst.
As the esterification catalyst, an esterification catalyst such as a tin compound such as dibutyltin oxide or tin dioctylate or a titanium compound such as titanium diisopropylate bistriethanolamate can be used. The amount of the esterification catalyst used is preferably 0.01 to 1 part by weight, more preferably 0.1 to 0.6 part by weight, based on 100 parts by weight of the total amount of the alcohol component and the carboxylic acid component.

  From the viewpoint of storage stability of the toner, the softening point of the polyester is preferably 70 to 165 ° C, more preferably 90 to 165 ° C, and the glass transition point is preferably 50 to 85 ° C, and preferably 55 to 85 ° C. Is more preferable. The acid value is preferably 6 to 35 mgKOH / g, more preferably 10 to 35 mgKOH / g, and still more preferably 15 to 35 mgKOH / g from the viewpoint of manufacturability. The desired softening point and acid value can be obtained by adjusting the charging ratio of alcohol and carboxylic acid, the polycondensation temperature, and the reaction time.

  In the present invention, the polyester includes not only unmodified polyester but also polyester modified to such an extent that the characteristics are not substantially impaired. Examples of the modified polyester include grafting and blocking with phenol, urethane, epoxy and the like by the methods described in JP-A-11-133668, JP-A-10-239903, JP-A-8-20636, and the like. And a composite resin having two or more kinds of resin units including a polyester unit.

When the resin particles in the resin particle dispersion contain a plurality of resins, the softening point, glass transition point, acid value and number average molecular weight of the resin constituting the resin particles are as a mixture of the resins. It means a softening point, a glass transition point, an acid value and a number average molecular weight, and each value is preferably the same value as that of the polyester.
Further, the resin may contain two kinds of polyesters having different softening points from the viewpoint of storage stability, fixing property and durability of the toner, and the softening point of one polyester (I) is 70 ° C. or higher and 115 ° C. The softening point of the other polyester (II) is preferably 115 ° C. or higher and 165 ° C. or lower. The weight ratio (I / II) between the polyester (I) and the polyester (II) is preferably 10/90 to 90/10, more preferably 50/50 to 90/10.

In the present invention, the resin constituting the resin particles is preferably dispersed in an aqueous medium. The aqueous medium in which the resin is dispersed is mainly composed of water. From the environmental viewpoint, the content of water in the aqueous medium is preferably 80% by weight or more, more preferably 90% by weight or more, and further preferably 100% by weight.
Examples of components other than water include alcohol-based organic solvents such as methanol, ethanol, isopropanol, and butanol, and organic solvents that dissolve in water such as acetone, methyl ethyl ketone, and tetrahydrofuran. Among these, from the viewpoint of preventing mixing into the toner, alcohol-based organic solvents such as methanol, ethanol, isopropanol, and butanol, which are organic solvents that do not dissolve the resin, can be used. In the present invention, it is preferable to atomize the resin using only water without substantially using an organic solvent.

In the resin particle dispersion obtained by dispersing the resin, additives such as a colorant, a release agent, and a charge control agent can be contained together with the resin as necessary.
Examples of the release agent include solid paraffin wax, rice wax, fatty acid amide wax, fatty acid wax, aliphatic monoketone, fatty acid metal salt wax, fatty acid ester wax, partially saponified fatty acid ester wax, and silicone varnish. Higher alcohol, carnauba wax and the like. Also, polyolefins such as low molecular weight polyethylene and polypropylene can be used. The said mold release agent can be used individually by 1 type or in combination of 2 or more types.

The melting point of these release agents is preferably from 60 to 90 ° C., more preferably from 65 to 90 ° C., from the viewpoint of toner fixability, and among them, the melting point is from 60 to 90 from the viewpoint of low temperature fixability of the toner. Paraffin waxes at 0 ° C. are preferred, ester waxes having a melting point of 60 to 90 ° C. are preferred from the viewpoint of compatibility with polyester, and carnauba wax is more preferred.
The content of the release agent is preferably 0.5 to 20 parts by weight, more preferably 1 to 18 parts by weight, and more preferably 1 to 18 parts by weight with respect to 100 parts by weight of the resin, from the viewpoint of dispersibility in the resin and toner fixability. Preferably it is 1.5-15 weight part.
The present invention is particularly preferable in that it can solve the problems of the present invention caused by bleed-out of a release agent when the toner contains a release agent.

The colorant is not particularly limited, and any known colorant can be used. Specifically, carbon black, inorganic complex oxide, chrome yellow, benzidine yellow, pyrazolone orange, vulcan orange, watch young red, brilliantamine 3B, brilliantamine 6B, lake red C, bengal, phthalocyanine blue, phthalocyanine green, etc. Various pigments and various dyes such as acridine, azo, benzoquinone, azine, anthraquinone, indico, thioindico, phthalocyanine, and aniline black are used singly or in combination of two or more. can do.
The content of the colorant is preferably 20 parts by weight or less, and more preferably 0.01 to 10 parts by weight with respect to 100 parts by weight of the resin.

Examples of the charge control agent include a metal salt of benzoic acid, a metal salt of salicylic acid, a metal salt of alkyl salicylic acid, a metal salt of catechol, a metal-containing bisazo dye, and a quaternary ammonium salt. These may be used individually by 1 type and may be used in combination of 2 or more type.
The content of the charge control agent is preferably 10 parts by weight or less, more preferably 0.01 to 5 parts by weight with respect to 100 parts by weight of the resin.

In the present invention, in the production of the resin particle dispersion, from the viewpoint of improving the dispersion stability of the resin, it is preferably 10 parts by weight or less, more preferably 5 parts by weight or less, more preferably 100 parts by weight of the resin. Is preferably 0.1 to 3 parts by weight, more preferably 0.5 to 2 parts by weight of a surfactant.
Examples of the surfactant include anionic surfactants such as sulfate ester, sulfonate, and soap; cationic surfactants such as amine salt type and quaternary ammonium salt type; polyethylene glycol type and alkylphenol ethylene Nonionic surfactants such as oxide adducts and polyhydric alcohols can be mentioned. Among these, ionic surfactants such as anionic surfactants and cationic surfactants are preferable. The nonionic surfactant is preferably used in combination with an anionic surfactant or a cationic surfactant. Although the said surfactant may be used individually by 1 type, you may use it in combination of 2 or more type.

Specific examples of the anionic surfactant include dodecyl benzene sulfonic acid, sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, sodium alkyl ether sulfate, and the like. Among these, sodium dodecylbenzenesulfonate is preferable.
Specific examples of the cationic surfactant include alkylbenzene dimethyl ammonium chloride, alkyl trimethyl ammonium chloride, distearyl ammonium chloride and the like.

  Nonionic surfactants include, for example, polyoxyethylene nonylphenyl ether, polyoxyethylene oleyl ether, polyoxyethylene alkyl aryl ethers such as polyoxyethylene lauryl ether, polyoxyethylene alkyl ethers, polyethylene glycol mono Examples thereof include polyoxyethylene fatty acid esters such as laurate, polyethylene glycol monostearate, and polyethylene glycol monooleate, and oxyethylene / oxypropylene block copolymers.

In preparing the resin particle dispersion, it is preferable to add an aqueous alkali solution to the resin and disperse the resin and additives used as necessary.
The alkaline aqueous solution preferably has a concentration of 1 to 20% by weight, more preferably 1 to 10% by weight, and still more preferably 1.5 to 7.5% by weight. As the alkali to be used, it is preferable to use an alkali that enhances the surface activity when the resin becomes a salt. Specific examples thereof include monovalent alkali metal hydroxides such as potassium hydroxide and sodium hydroxide.
After the dispersion, preferably after neutralizing at a temperature above the glass transition point of the resin, an aqueous medium is added at a temperature above the glass transition point to emulsify the resin particle dispersion. .

The addition rate of the aqueous medium is preferably from 0.1 to 50 g / min, more preferably from 0.5 to 40 g / min, and even more preferably from 1 to 30 g / min per 100 g of resin from the viewpoint that emulsification can be effectively carried out. min. This addition rate is generally maintained until an O / W type emulsion is substantially formed, and there is no particular limitation on the addition rate of water after the formation of the O / W type emulsion.
Examples of the aqueous medium used for the production of the resin emulsion include the same aqueous medium used for dispersing the resin constituting the resin particles described above, and preferably deionized water or distilled water.
The amount of the aqueous medium is preferably from 100 to 2,000 parts by weight, more preferably from 150 to 1,500 parts by weight, based on 100 parts by weight of the resin, from the viewpoint of obtaining uniform aggregated particles in the subsequent aggregation treatment. From the viewpoint of stability and handleability of the obtained resin dispersion, the solid content concentration of the resin dispersion is preferably 7 to 50% by weight, more preferably 7 to 40% by weight, and still more preferably 10 to 35% by weight. The amount of the aqueous medium is selected so that In addition, non-volatile components, such as resin and a nonionic surfactant, are contained in solid content.

Moreover, it is preferable that the temperature in this case is the range beyond the glass transition point of a resin and below a softening point from a viewpoint of preparing a fine resin dispersion. By carrying out the emulsification at a temperature within the above range, the emulsification is carried out smoothly and no special apparatus is required for heating. From this point, the temperature is preferably equal to or higher than (glass transition point of the resin +10) ° C. (meaning “temperature higher by 10 ° C. than the glass transition point”, hereinafter the same notation is similarly understood). (Resin softening point -5) ° C. or lower is preferable.
The volume median particle size (D50) of the resin particles in the resin particle dispersion thus obtained is preferably 0.02 to 2 μm, more preferably for uniform aggregation in the subsequent aggregation treatment. Is 0.05-1 μm, more preferably 0.05-0.6 μm. Here, “volume median particle size (D50)” means a particle size at which the cumulative volume frequency calculated by the volume fraction is 50% when calculated from the smaller particle size.

Examples of other methods for obtaining a resin particle dispersion include, for example, a method in which a polycondensable monomer is first emulsified and dispersed in an aqueous medium by, for example, mechanical shearing or ultrasonic waves as a target resin particle raw material. . At this time, additives such as a polycondensation catalyst and a surfactant are also added to the water-soluble medium as necessary. And polycondensation is advanced by, for example, heating the solution. For example, when the resin is polyester, the above-mentioned polyester polycondensable monomer and polycondensation catalyst can be used, and the above-mentioned surfactants can be used similarly.
Usually, polycondensation resins do not proceed in an aqueous medium in principle because they are dehydrated during polymerization. However, for example, when a polycondensable monomer is emulsified in an aqueous medium together with a surfactant that forms micelles in the aqueous medium, the monomer is placed in a micro hydrophobic field in the micelle. Then, dehydration occurs, and the generated water can be discharged into an aqueous medium outside the micelles to allow polymerization to proceed. In this way, a dispersion liquid in which the resin particles of the polycondensation resin are emulsified and dispersed in an aqueous medium is obtained with low energy.

(Aggregated particle dispersion)
In step 1, an aggregating agent is added to the obtained resin particle dispersion so as to have an aggregating agent concentration Ea (wt%), and the resin particles in the resin particle dispersion are agglomerated to obtain an agglomerated particle dispersion. (Hereinafter, step 1 may be referred to as “aggregation step”).
In the present invention, organic flocculants include organic salts and polyethyleneimine as the flocculant, and inorganic flocculants include inorganic metal salts, inorganic ammonium salts, metal complexes, and the like. Examples of the organic salt include sodium acetate and ammonium acetate, and examples of the inorganic metal salt include metal salts such as sodium sulfate, sodium chloride, calcium chloride, magnesium chloride, aluminum chloride, and aluminum sulfate, and inorganic metals such as polyaluminum chloride. A salt polymer is mentioned. Examples of the inorganic ammonium salt include ammonium sulfate, ammonium chloride, and ammonium nitrate.

  In the present invention, from the viewpoint of achieving highly accurate toner particle size control and sharp particle size distribution, it is preferable to use a monovalent salt among the aggregating agents. Here, the monovalent salt means that the valence of the metal ion or cation constituting the salt is 1. As the monovalent salt, an inorganic flocculant such as an inorganic metal salt or ammonium salt is used. In the present invention, a water-soluble nitrogen-containing compound having a molecular weight of 350 or less is preferably used.

  The water-soluble nitrogen-containing compound having a molecular weight of 350 or less is preferably a compound that exhibits acidity from the viewpoint of rapidly agglomerating resin particles, and a pH value at 25 ° C. of a 10 wt% aqueous solution thereof is 4-6. Are preferable, and 4.2 to 6 are more preferable. Further, from the viewpoint of chargeability of the toner at high temperature and high humidity, the molecular weight is preferably 350 or less, more preferably 300 or less. Examples of such water-soluble nitrogen-containing compounds include ammonium salts such as ammonium halide, ammonium sulfate, ammonium acetate, and ammonium salicylate, and quaternary ammonium salts such as tetraalkylammonium halides. , Ammonium sulfate (pH value of a 10% by weight aqueous solution at 25 ° C., hereinafter referred to as pH value: 5.4), ammonium chloride (pH value: 4.6), tetraethylammonium bromide (pH value: 5.6), odor Preferred is tetrabutylammonium bromide (pH value: 5.8).

In the present invention, the flocculant is added so as to have a flocculant concentration Ea (wt%). The flocculant concentration Ea is calculated by the following formula.
Ea (weight%) = [addition amount of aggregating agent (g) / weight of agglomerated particle dispersion (g)] × 100
Here, the “weight of the aggregated particle dispersion” refers to the weight of the aggregated particle dispersion after aggregation, but before aggregation or in the aggregation process, unaggregated resin particles, other additive particles, etc. It refers to the total weight of the dispersion liquid containing and the aggregate particle dispersion liquid in the aggregation process.

The concentration of the flocculant in the aggregation step is preferably 0.0001 to 10 mol / L from the viewpoint of aggregation properties. If the amount of the aggregating agent is small, the particles cannot be agglomerated and the resin particles cannot be grown into toner particles. On the other hand, if the amount of the aggregating agent is too large, the particle size of the agglomerated particles cannot be controlled and the desired particle size is not obtained. Toner cannot be obtained. The concentration of the flocculant may vary depending on the valence of the flocculant used. If the valence of the flocculant is z, it is described in “Latest Colloid Chemistry” (Kitahara, Furuzawa, 1990, Kodansha Scientific). As described above, since the cohesiveness of the resin particles is proportional to the sixth power of the valence of the coagulant, the coagulant concentration is preferably 0.1 × z ⁻⁶ to 10 × z ⁻⁶ (mol / L).
More preferably, within the range of
0.1 × z ⁻⁶ to 1 × z ⁻⁶ (mol / L)
The flocculant concentration may be adjusted so as to be within the range of.

  As described above, the concentration of the flocculant varies depending on the valence of the flocculant. However, when a monovalent flocculant is used, the flocculant concentration Ea (% by weight) is determined from the viewpoint of flocculence control. The content is preferably in the range of 1 to 10% by weight with respect to the particle dispersion, more preferably 1.5 to 8% by weight, and still more preferably 2 to 5% by weight. If the concentration of the flocculant is within the above range, aggregation is likely to proceed, formation of coarse particles is suppressed, and particle size control is facilitated.

  Further, from the viewpoint of the charging property of the toner, particularly the charging property in a high temperature and high humidity environment, the addition amount of the flocculant is 50 parts by weight or less with respect to 100 parts by weight of the resin constituting the resin particles of the resin particle dispersion. The amount is preferably 40 parts by weight or less, and more preferably 30 parts by weight or less. Moreover, from a cohesive viewpoint, 1 weight part or more is preferable with respect to 100 weight part of said resin, 3 weight part or more is more preferable, and 5 weight part or more is still more preferable. Considering the above points, the use amount of the flocculant is preferably 1 to 50 parts by weight, more preferably 3 to 40 parts by weight, and still more preferably 5 to 30 parts by weight with respect to 100 parts by weight of the resin.

  In step 1, from the viewpoint of cohesiveness and control of the particle size distribution of the aggregated particles, the temperature Ta in the aggregation system (the dispersion containing the coagulant and the resin particles and / or aggregated particles) is set to (resin constituting the resin particles). It is preferable to set it as the temperature below the glass transition point Tg-30) degreeC or more (glass transition point Tg + 25 of the said resin) degreeC. If the temperature is within the above range, the fusion of the aggregated particles is difficult to proceed, and the generation of coarse particles can be suppressed. Therefore, from the viewpoint of suppressing coarse particles, the temperature is preferably (Tg-30 of the resin constituting the resin particles) ° C. to (Tg + 25 ° C. of the resin), more preferably (Tg-25 of the resin). C. to (Tg of the resin + 25) .degree. C., more preferably (Tg-20 of the resin) .degree. C. to (Tg + 15 of the resin) .degree. C., even more preferably (Tg-15 of the resin) .degree. C. to (Tg + 5 of the resin). ) In the range of ° C.

In the present invention, from the viewpoint of low-temperature fixability and storage stability of the toner, a release agent dispersion in which the release agent is dispersed in an aqueous medium is mixed with a resin particle dispersion, and an aggregating agent is added to agglomerate. It is preferable to make it. In the preparation of the release agent dispersion, the release agent is dispersed in an aqueous medium in the presence of a surfactant and dispersed into fine particles with a homogenizer or an ultrasonic disperser while being heated above the melting point of the release agent. The volume median particle size (D50) is preferably a dispersion of release agent particles having a particle size of 1 μm or less.
In the present invention, when the resin constituting the resin particles is a resin having an acid group such as polyester, a polymer having an oxazoline group is mixed at a temperature of 60 to 100 ° C. from the viewpoint of storage stability of the toner. It is preferable to use crosslinked resin particles obtained by crosslinking resin particles. By aggregating the crosslinked resin particles in this way, the softening point of the resin particles is increased and the storage stability of the toner is increased, and also when the release agent is used in combination, release of the release agent from the aggregated particles is suppressed. There is also an effect.

  As the polymer having an oxazoline group, a polymer having two or more oxazoline groups in the molecule can be used. This polymer causes a cross-linking reaction with a resin having an acid group such as a carboxyl group constituting the resin particle. The polymer having an oxazoline group is obtained from a polymerizable monomer having an oxazoline group, for example. If necessary, it can also be obtained by copolymerization of a polymerizable monomer having an oxazoline group and a polymerizable monomer copolymerizable therewith.

  The polymerizable monomer having an oxazoline group is not particularly limited, and examples thereof include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2- Oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline, etc. Is mentioned. These may be used alone or in combination of two or more. Among these, 2-isopropenyl-2-oxazoline is preferable because it is easily available industrially.

The flocculant can be added in the form of an aqueous medium solution for uniform agglomeration. As the aqueous medium that can be used, the same ones used in the production of the resin particle dispersion described above can be used. The flocculant may be added at once, or may be added intermittently or continuously. Furthermore, it is preferable to sufficiently stir at the time of adding the flocculant and after the addition is completed.
The solid content concentration in the dispersion of the aggregated particles obtained in Step 1 is preferably 5 to 50% by weight, more preferably 5 to 40% by weight, from the viewpoint of productivity of the aggregated particle dispersion and control of aggregation. It is.

Thus, the aggregated particle dispersion is prepared by aggregating the resin particles in the resin particle dispersion.
The aggregated particles contained in this aggregated particle dispersion have a volume median particle size (D50) in the range of 1 to 10 μm, more preferably 2 to 9 μm, and even more preferably 2 to 5 μm, from the viewpoint of reducing the particle size. Preferably there is. The variation coefficient (CV value) of the particle size distribution is preferably 30% or less, more preferably 28% or less, and further preferably 25% or less.
The coefficient of variation (CV value) of the particle size distribution is expressed by the formula CV value (%) = [standard deviation of particle diameter (μm) / volume median particle diameter (μm)] × 100
It is a value represented by

[Step 2]
Step 2 is a step of adding a resin fine particle dispersion to the aggregated particle dispersion obtained in Step 1 to obtain a resin fine particle-attached aggregated particle dispersion having a coagulant concentration Eb (% by weight) satisfying the following formula 1. It is.
0.60 ≦ Eb / Ea <1 (1)
Here, the flocculant concentration Eb is calculated by the following equation.
Eb (% by weight) = [addition amount of aggregating agent (g) / weight of resin fine particle-attached aggregated particle dispersion (g)] × 100

In this way, by adding the resin fine particle dispersion to the aggregated particle dispersion to obtain a dispersion of resin fine particle-attached aggregated particles containing the resin fine particle-attached aggregated particles, various resin particles can be easily encapsulated. Can do.
In the present invention, by adjusting the coagulant concentration Eb so as to satisfy the formula 1, the resin fine particles uniformly adhere to the surface of the aggregated particles, so that the storage stability of the obtained toner and the environmental stability of charging are improved. It is considered to be done.
The addition of the resin fine particle dispersion may be performed at one time, may be performed in a plurality of times, or each addition may be performed separately, from the viewpoint of controlling the particle size of the aggregated particles Therefore, the concentration of the flocculant is preferably maintained at a concentration Eb within the range satisfying the substantial formula (1) while the resin fine particles are adhered to the aggregated particles. Here, “substantial” means that it is only required to be maintained within the range as long as the effects of the present invention are exhibited, and includes cases where the range temporarily deviates from the range.

That is, in step 2, the concentration of the flocculant is reduced by the addition of the resin fine particle dispersion, but when the flocculant concentration deviates from the lower limit of the formula (1), the flocculant is further added, It is preferable to maintain the concentration within the above range. The amount of the flocculant can be determined according to the concentration of the flocculant in the system at that time, that is, the addition speed of the resin fine particle dispersion. It is preferable to add so that the concentration of the aggregating agent in the dispersion containing the agent particles and the resin fine particles satisfies Eb represented by Formula 1. From the viewpoint of storage stability of toner and environmental stability of charging property, the Eb is represented by the formula (1 ′).
0.65 ≦ Eb / Ea ≦ 0.95 (1 ′)
And more preferably, the formula (1 ″)
0.70 ≦ Eb / Ea ≦ 0.90 (1 ″)
Meet.

  Step 2 is performed at a temperature similar to the temperature Ta of Step 1, that is, at a temperature equal to or lower than (the glass transition point Tg + 25 of the resin constituting the resin particles) from the viewpoint of uniformly attaching the resin fine particles to the aggregated particles. Preferably, (Tg-30) ° C. to (Tg + 25 ° C.), more preferably 25 ° C. to (Tg + 25) ° C., more preferably 25 ° C. to (Tg + 15) ° C., more preferably 35 ° C. to ( The Tg + 5) ° C., particularly preferably 40 ° C. to (the Tg−5) ° C.

As the resin constituting the resin fine particles, the same resin as the resin constituting the above-described resin particles can be used, but when using a different resin, the effects of the present invention can be effectively achieved.
The addition speed of the resin fine particle dispersion is 0 for the resin constituting the resin fine particles with respect to 100 parts by weight of the resin in the aggregated particles from the viewpoint of controlling the particle diameter of the aggregated particles and from the viewpoint of the cohesiveness and productivity. The addition rate is preferably 0.05 to 2.0 parts by weight / minute, more preferably 0.05 to 1.5 parts by weight / minute.

The resin fine particle dispersion can be prepared in the same manner as the above-described method for preparing the resin particle dispersion, and similarly, the resin fine particles in the resin fine particle dispersion preferably contain polyester. In the preparation of the resin fine particle dispersion, when dispersing the resin constituting the resin fine particles, it is preferable to use a surfactant in the same manner as the method for preparing the resin particle dispersion in Step 1, The amount is the same as in the method for preparing the resin particle dispersion.
In the resin fine particle dispersion, additives such as a colorant, a release agent, and a charge control agent can be contained together with the resin as necessary. These may be the same as those described in the preparation of the resin particle dispersion in Step 1 above.

The solid content concentration in the resin fine particle dispersion is preferably 7 to 50% by weight, more preferably 7 to 40% by weight, and still more preferably 10 to 10% from the viewpoint of the stability of the dispersion and uniform adhesion to the aggregated particles. 35% by weight.
The volume median particle size (D50) of the resin fine particles thus obtained is preferably 0.02 to 2 μm, more preferably 0.05 to 1 μm, and 0.05 to 0.6 μm from the viewpoint of uniform aggregation. Is more preferable.
The addition ratio of the resin fine particles in the resin fine particle dispersion to the aggregated particles is preferably 5 in the resin fine particles with respect to 100 parts by weight of the resin in the aggregated particles from the viewpoint of storage stability and chargeability of the toner. -100 parts by weight, more preferably 10-90 parts by weight, still more preferably 20-80 parts by weight.

  In Step 2, when the resin fine particle dispersion is added in a plurality of portions, the amount of the resin fine particles contained in each dispersion is preferably the same amount, and the flocculant is added in portions. In some cases, it is preferred that each flocculant be the same amount. In addition, when the resin fine particle dispersion is added in a plurality of times, there is no particular limitation on the number of times, but from the viewpoint of the particle size distribution and productivity of the formed resin fine particle adhered aggregated particles, 2 to 10 times. Is preferable, and 2 to 8 times is more preferable.

  In addition, from the viewpoint of cohesiveness and the particle size distribution of the formed resin fine particle adhered aggregate particles, in the addition of the resin fine particle dispersion multiple times, 5 to 15 minutes after the addition, further 5 to 30 minutes, especially 5 minutes. It is preferable to ripen for 2 hours, and it is more preferable to provide the aging time for all the additions of multiple times. The aging time is the time from the end of addition until the start of addition of the flocculant and / or resin fine particle dispersion in the next addition.

  In step 2, from the viewpoint of improving the image quality of the toner, the volume median particle size (D50) of the resin fine particle-attached aggregated particles is preferably 1 to 10 μm, more preferably 2 to 10 μm, and further preferably 3 to 10 μm. preferable.

[Step 3]
Step 3 is a step of adjusting the coagulant concentration of the dispersion of the resin fine particle-attached aggregated particles obtained in Step 2 to the coagulant concentration Ec (% by weight) satisfying the following formula 2.
0.005 ≦ Ec / Ea ≦ 0.30 (2)
Here, the coagulant concentration Ec is calculated by the following equation, as in Eb.
Ec (wt%) = [addition amount of aggregating agent (g) / weight of dispersion of resin fine particle-attached agglomerated particles (g)] × 100
In the present invention, at least the storage stability of the obtained toner can be improved by adjusting the flocculant concentration Ec so as to satisfy the formula (2).
Further, the coagulant concentration Ec (% by weight) is expressed by Formula 2-1.
0.08 <Ec / Ea ≦ 0.30 (2-1)
By satisfying the above, it is possible to obtain an electrophotographic toner in which the storage stability of the toner, the environmental stability of the charge amount, and the scattering property are all improved, and the flocculant concentration Ec (% by weight) is Formula 2-2
0.005 ≦ Ec / Ea ≦ 0.08 (2-2)
By satisfying the above, it is possible to obtain an electrophotographic toner having both improved storage stability and transferability of the toner.

That is, in Step 3, from the viewpoint of improving the storage stability of the toner, the environmental stability of the charge amount, and the low scattering property, the concentration of the flocculant Ec (wt%) is obtained after preparing the resin fine particle-attached aggregated particles in Step 2. Preferably, formula 2-1
0.08 <Ec / Ea ≦ 0.30 (2-1)
More preferably, the expression 2-1 ′ is satisfied.
0.09 ≦ Ec / Ea ≦ 0.28 (2-1 ′)
More preferably, formula 2-1 ″ so as to satisfy
0.09 ≦ Ec / Ea ≦ 0.25 (2-1 ″)
Adjust to meet.

  When the coagulant concentration ratio (Ec / Ea) is higher than 0.08, the obtained chargeability is improved, and not only preservability but also excellent environmental stability and low scattering property can be realized. Although the detailed reason is unknown, when the concentration ratio of the flocculant is in the above range, the fusion of the resin fine particles proceeds faster than the fusion of the aggregated particles in the fusion process. For this reason, since the resin fine particles are fused on the resin particles before the aggregated particles are fused, that is, before the interface disappears, it is considered that the toner surface shape is smooth but has unevenness. It is considered that this unique shape has an influence on the chargeability. Further, when the coagulant concentration ratio Ec / Ea is 0.30 or less, the fusion of the resin fine particle-adhering particles is easy to proceed, the coalescence is sufficiently performed, and the storage stability is improved.

In Step 3, from the viewpoint of achieving both storage stability and transferability of the toner, after preparing the resin fine particle-attached aggregated particles in Step 2, the coagulant concentration Ec is preferably expressed by Formula 2-2.
0.005 ≦ Ec / Ea ≦ 0.08 (2-2)
More preferably, the expression 2-2 ′ is satisfied.
0.005 ≦ Ec / Ea ≦ 0.06 (2-2 ′)
More preferably, formula 2-2 ″ so as to satisfy
0.005 ≦ Ec / Ea ≦ 0.04 (2-2 ″)
Adjust to meet.
If the coagulant concentration ratio (Ec / Ea) is 0.05 or more, the resin fine particle-attached aggregate particles in the dispersion can exist stably, and the particles having a uniform shape do not cause the resin fine particles to be detached. The formed toner has good transferability and storage stability, and if the flocculant concentration ratio (Ec / Ea) is 0.08 or less, the shape of the toner approaches a true sphere and transferability is good. Tend to be.

In Step 3, the flocculant concentration Ec is preferably adjusted by adding an aqueous medium to the resin particle-adhered aggregated particle dispersion obtained in Step 2. The aqueous medium may be added all at once or separately, or may be added dropwise at once or continuously. As the aqueous medium that can be added, the same medium as used in the production of the resin particles can be used.
From the viewpoints of particle size control and productivity of the resin fine particle-attached aggregated particles, the resin fine particle-attached aggregated particles are preferably prepared within 1 hour, more preferably within 30 minutes, and even more preferably after the resin fine particle-attached aggregated particles are prepared to a desired particle size. The flocculant concentration Ec is adjusted to satisfy the above range within 10 minutes. Preparation of the resin fine particle adhesion aggregated particles can be performed by monitoring the particle size of the resin fine particle adhesion aggregated particles.
Further, the temperature in step 3 is not particularly limited, but from the viewpoint of the stability of the resin fine particle-attached aggregated particles in the dispersion, it should be performed at the temperature at which the resin fine particle-attached aggregated particle dispersion in step 2 is produced. Is preferred.

In the present invention, from the viewpoint of preventing further aggregation, it is preferable to have a step of adding an aggregation terminator before coalescence. A surfactant is preferably used as the aggregation terminator, but an anionic surfactant is more preferably used. Of the anionic surfactants, it is more preferable to add at least one selected from the group consisting of alkyl ether sulfates, alkyl sulfates, and linear alkylbenzene sulfonates.
In the present invention, from the viewpoint of uniformly fusing the agglomerated particles and improving the storage stability and chargeability of the resulting toner, an aggregation terminator represented by the following formula (3) is added. It is preferable.
R—O— (CH ₂ CH ₂ O) nSO ₃ M (3)
(In the formula, R represents an alkyl group, M represents a monovalent cation, and n represents an average addition mole number of 0 to 15.)

In the formula (1), the alkyl group represented by R is preferably 4 to 16 carbon atoms, more preferably 6 to 14 carbon atoms, and still more preferably from the viewpoint of adsorptivity to aggregated particles and persistence to toner. Include those having 8 to 12 carbon atoms, and specifically include butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, tetradecyl, pentadecyl and the like. . The average added mole number n is 0 to 15, but preferably 0 to 5, more preferably 0 to 3, from the viewpoint of particle size control. M is a monovalent cation, but from the viewpoint of particle size control, a monovalent metal or ammonium is preferable, sodium, potassium, lithium, or ammonium is more preferable, and sodium or ammonium is more preferable.
Specific examples of the aggregation terminator used in the present invention include C ₁₂ H ₂₅ (OCH ₂ CH ₂ ) ₂ OSO ₃ Na, C ₁₂ H ₂₅ (OCH ₂ CH ₂ ) ₃ OSO ₃ Na, and the like.
The aggregation terminator may be used alone or in combination of two or more.

The addition amount of the aggregation terminator is a resin constituting the resin fine particle-attached aggregated particles (that is, the total amount of the resin constituting the aggregated particles and the resin constituting the resin fine particles) from the viewpoint of the aggregation termination property and the persistence to the toner. Preferably it is 0.1-15 weight part with respect to 100 weight part, More preferably, it is 0.1-10 weight part, More preferably, it is 0.1-8 weight part. These may be added in any form as long as they are added, but are preferably added in an aqueous solution from the viewpoint of productivity.
In the present invention, when adjusting the dispersion of resin fine particle-adhered aggregated particles to the above-mentioned coagulant concentration ratio Ec, addition of an aqueous solution of the above-mentioned aggregation terminator can also be performed at low temperature, and the resulting toner This is a preferred embodiment from the viewpoint of improving the chargeability. In this case, the coagulant concentration ratio Ec / Ea is preferably adjusted by adjusting the concentration of the aqueous solution of the coagulation terminator, that is, the amount of dilution water of the coagulation terminator.
The aggregation terminator may be added at once, or may be added intermittently or continuously.

[Step 4]
In the present invention, after step 3, step 4 (hereinafter referred to as “unification step”) is performed to coalesce the resin fine particle-attached aggregate particles in the dispersion of resin fine particle-attached aggregate particles whose coagulant concentration is adjusted to Ec. ). That is, in step 4, the resin fine particle-attached aggregated particles in the dispersion of the resin fine particle-attached aggregated particles having the coagulant concentration ratio Ec obtained in step 3 are converted into the glass transition point Tg (° C.) of the resin fine particles in the resin fine particle dispersion. ) Above, it is a step of heating and coalescing at a temperature of (Tg + 20) ° C. or less.

  In step 4, the resin fine particle-attached aggregated particles are heated to coalesce the aggregated particle portions of the resin fine particle-attached aggregated particles, and the resin fine particles are fused to the aggregated particles to obtain coalesced particles. That is, the resin fine particle-attached aggregated particles are mainly physically attached to the resin particles in the aggregated particles, the resin fine particles in the resin fine particle-attached aggregated particles, and the aggregated particles and the resin fine particles in the resin fine particle-attached aggregated particles. In the coalescence process, the aggregated particles (also referred to as core particles) are united and united, and the resin fine particles, and the core particles and resin microparticles are fused and united, Presumed to be a coalesced particle.

The heating temperature in Step 4 is the target toner particle size, particle size distribution, shape control, and fusing property of the resin particle adhering aggregated particles, as well as storage stability of the toner, environmental stability of the charge amount, and scattering properties. From the viewpoint, the glass transition point Tg of the resin fine particles in the resin fine particle dispersion is preferably not less than (Tg + 15 of the resin fine particles) ° C., and more preferably (Tg of the resin fine particles) ° C. It is Tg + 10) ° C. or less of the fine particles, and more preferably (Tg of the resin fine particles) ° C. or more and (Tg + 5 of the resin fine particles) ° C. or less.
In addition to the particle size, particle size distribution, shape control of the toner, and the fusing property of the agglomerated particles adhering to the resin particles, from the viewpoint of storage stability and transferability of the toner, (Tg of the resin particles) is preferably It is more than (Tg + 10 of the resin fine particles) ° C. or less, more preferably (Tg of the resin fine particles) ° C. or more and (Tg + 5 of the resin fine particles) ° C. or less.

In the present invention, when a release agent is used, from the viewpoint of low toner scattering and environmental stability of the charge amount, the heating temperature is the glass transition point Tg of the resin fine particles in the resin fine particle dispersion to be used. It is preferable that the temperature is not lower than (° C.) and (melting point of release agent particles−5) ° C., preferably not lower than Tg (° C.) of the resin fine particles and (melting point of release agent particles−7) ° C. It is more preferable that the temperature be (Tg + 5 of the resin fine particles) ° C. or higher, and more preferable that the temperature is (melting point of release agent particles−10) ° C. or lower.
The holding time at the heating temperature in step 4 is not particularly limited as long as aggregation of the aggregated particles and resin fine particles is sufficiently performed, but from the viewpoint of toner charging property, it is preferably 0.5 to 20 hours. More preferably, it is 1 to 10 hours.

The obtained coalesced particles become toner particles through a solid-liquid separation process such as filtration, a washing process, and a drying process. Here, in order to ensure sufficient charging characteristics and reliability as a toner, it is preferable to perform cleaning with an acid in order to remove metal ions on the toner surface in the cleaning step.
In the drying step, any method such as a vibration type fluidized drying method, a spray drying method, a freeze drying method, a flash jet method, or the like can be employed. The water content after drying of the toner particles is preferably adjusted to 1.5% by weight or less, more preferably 1.0% by weight or less, from the viewpoint of chargeability of the toner.
From the viewpoint of high image quality, the volume-median particle size (D50) of the coalesced particles is preferably 1 to 10 μm, more preferably 2 to 8 μm, and even more preferably 3 to 8 μm.

<Toner for electrophotography>
The toner for electrophotography obtained by the production method of the present invention is obtained by the production method having steps 1 to 4, and all of the storage stability of the toner, the environmental stability of the charge amount, and the scattering property are all obtained. In addition, the storage stability and the transferability are improved at the same time. Details of each of Steps 1 to 4 are as described above.

  The softening point of the toner is preferably 60 to 140 ° C., more preferably 60 to 130 ° C., and still more preferably 60 to 120 ° C. from the viewpoint of low-temperature fixability. The glass transition point is preferably 30 to 80 ° C., more preferably 40 to 70 ° C., from the viewpoint of toner durability. In addition, the measuring method of a softening point and a glass transition point is based on these measuring methods in resin.

The BET specific surface area of the toner particles by the nitrogen adsorption method is preferably 1.5 to 6.0 m ² / g from the viewpoints of suppression of toner scattering and storage stability. BET specific surface area is more preferably 1.5~4.0m ² / g from the viewpoint of storage stability, more preferably 1.5~3.0m ² / g.
Further, the circularity is preferably from 0.930 to less than 0.980, more preferably from 0.940 to 0.975, from the viewpoints of storage stability of the toner, environmental stability of the charge amount, and suppression of scattering properties. More preferably, the toner has a circularity of 0.930 to less than 0.980 (sometimes referred to as “pseudo-spherical toner”). Further, from the viewpoint of achieving both storage stability and transferability of the toner, 0.980 or more is preferable, 0.982 or more is more preferable, and 0.985 or more is more preferable (hereinafter, toner having a circularity of 0.980 or more is used. Sometimes called “spherical toner”.)

The pseudo-spherical toner can be obtained by adjusting the flocculant concentration Ec in Step 3 so as to satisfy 0.08 <Ec / Ea ≦ 0.30. The spherical toner can be obtained by adjusting the flocculant concentration ratio (Ec / Ea) in step 3 so as to satisfy 0.005 ≦ Ec / Ea ≦ 0.08. In the present invention, the circularity of the toner particles is a value obtained by the ratio of the circumference of the circle equal to the projected area / the circumference of the projected image, and the roundness of the toner particles is closer to 1 as the particles are spherical. Value.
The BET specific surface area and the circularity of the toner particles can be measured by the method described later.

  When a release agent, a colorant, a charge control agent, or the like is used, the content of the release agent, the colorant, and the charge control agent with respect to 100 parts by weight of the binder resin in the toner is as follows. From the viewpoint of fixability, it is preferably 0.5 to 20 parts by weight, more preferably 1 to 18 parts by weight, still more preferably 1.5 to 15 parts by weight, and the colorant is preferably 20 parts by weight or less. More preferably, it is 0.01-10 weight part, About a charge control agent, Preferably it is 10 weight part or less, More preferably, it is 0.01-5 weight part.

In the present invention, the toner particles obtained by the above production method may be used as a toner as they are, or a toner obtained by adding an additive such as a fluidizing agent to the toner particle surface as an external additive is used as the toner. be able to. External additives include known fine particles such as silica fine particles, titanium fine particles, alumina fine particles, cerium oxide fine particles, carbon black and other inorganic fine particles, and polymer fine particles such as polycarbonate, polymethyl methacrylate and silicone resin. Can be used.
The amount of the external additive is preferably 1 to 5 parts by weight and more preferably 1.5 to 3.5 parts by weight with respect to 100 parts by weight of the toner before processing with the external additive.

From the viewpoint of high image quality, the volume median particle size (D50) of the toner particles is preferably 1 to 10 μm, more preferably 2 to 8 μm, and even more preferably 3 to 8 μm. Further, the CV value of the coalesced particles and toner particles described above is preferably 30 or less, and more preferably 27 or less. The particle size and particle size distribution of the toner particles can be measured by the method described later.
The electrophotographic toner obtained by the production method of the present invention can be used as a one-component developer or as a two-component developer mixed with a carrier.

Hereinafter, the present invention will be described more specifically with reference to examples, but the substance of the present invention is not limited to the following examples.
In the following examples and the like, each property value was measured and evaluated by the following method.
[Acid value of resin]
Measured according to JIS K0070. However, the measurement solvent was a mixed solvent of acetone and toluene (acetone: toluene = 1: 1 (volume ratio)).

[Softening point and glass transition point of resin and toner]
(1) Softening point Using a flow tester (Shimadzu Corporation, “CFT-500D”), a 1 g sample was heated at a heating rate of 6 ° C./min, a load of 1.96 MPa was applied by a plunger, a diameter of 1 mm, Extrude from a 1 mm long nozzle. Plot the flow tester drop by the flow tester against the temperature, and let the softening point be the temperature at which half the sample flowed out.

(2) Glass transition point The temperature was raised to 200 ° C using a differential scanning calorimeter (manufactured by Parkin Elmer, Pyris6 DSC), and the sample cooled from that temperature to -10 ° C at a rate of temperature drop of 10 ° C / min was heated up. Measure at 10 ° C / min. When a peak is observed at a temperature 20 ° C. or more lower than the softening point, the peak temperature is measured. When a peak is not observed at a temperature 20 ° C. or higher lower than the softening point, a step is observed. The temperature at the intersection of the tangent line indicating the maximum slope of the curve and the extension line of the base line on the high temperature side of the step is read as the glass transition point. The glass transition point is a physical property peculiar to the amorphous part of the resin, and is generally observed in amorphous polyester, but is observed when amorphous part exists even in crystalline polyester. There is.

[Number average molecular weight of resin]
The molecular weight distribution is measured by gel permeation chromatography and the number average molecular weight is calculated by the following method.
(1) Preparation of sample solution The resin is dissolved in chloroform so that the concentration is 0.5 g / 100 ml. Next, this solution is filtered using a fluororesin filter having a pore size of 2 μm [manufactured by Sumitomo Electric Industries, Ltd., “FP-200”] to remove insoluble components to obtain a sample solution.
(2) Molecular weight distribution measurement Using the following apparatus, chloroform is flowed at a flow rate of 1 ml per minute, and the column is stabilized in a constant temperature bath at 40 ° C. 100 μl of the sample solution is injected therein and measurement is performed. The molecular weight of the sample is calculated based on a calibration curve prepared in advance. The calibration curve at this time includes several types of monodisperse polystyrene (2.63 × 10 ³ , 2.06 × 10 ⁴ , 1.02 × 10 ⁵ manufactured by Tosoh Corporation, and 2.10 × 10 ³ manufactured by GL Sciences, Inc. , 7.00 × 10 ³ , 5.04 × 10 ⁴ ) are used as standard samples.
Measuring device: CO-8010 (manufactured by Tosoh Corporation)
Analysis column: GMHLX + G3000HXL (manufactured by Tosoh Corporation)

[Softening point and glass transition point of resin particles]
Using a freeze dryer (Tokyo Rika Instruments: FDU-2100 and DRC-1000), 30 g of the dispersion was vacuum-dried at -25 ° C for 1 hour, -10 ° C for 10 hours, and 25 ° C for 4 hours. And dried until the water content was 1% by weight or less.
Moisture content was measured using an infrared moisture meter (Kett Science Laboratory Co., Ltd .: FD-230), dried sample 5 g, drying temperature 150 ° C., measurement mode 96 (monitoring time 2.5 minutes / variation width 0.05%) The water content (% by weight) was measured at
The softening point and glass transition point of the particles in the dried dispersion are measured by the methods described above.

[Particle size of resin particles and release agent particles]
(1) Measuring apparatus: Laser scattering type particle size measuring machine (LA-920, manufactured by HORIBA, Ltd.)
(2) Measurement conditions: Distilled water is added to the measurement cell, and the volume-median particle size (D50) at a temperature at which the absorbance falls within an appropriate range.

[Solid concentration of dispersion]
Using an infrared moisture meter (Kett Science Laboratory Co., Ltd .: FD-230), 5 g of the dispersion was dried at a drying temperature of 150 ° C. and in a measurement mode 96 (monitoring time 2.5 minutes / variation width 0.05%). % Is measured. The solid content was calculated according to the following formula.
Solid content (%) = 100-M
M: moisture (%) = [(W−W0) / W] × 100
W: Sample weight before measurement (initial sample weight)
W0: Sample weight after measurement (absolute dry weight)

[Agglomerated particles, resin particle adhered aggregated particles, coalesced particle size]
・ Measuring machine: Coulter Multisizer III (Beckman Coulter)
・ Aperture diameter: 50μm
-Analysis software: Multisizer III version 3.51 (manufactured by Beckman Coulter)
・ Electrolyte: Isoton II (Beckman Coulter)
Measurement conditions: After adjusting the particle size of 30,000 particles to a concentration that can be measured in 20 seconds by adding the aggregated particle dispersion, the resin particle-attached aggregated particle dispersion, and the coalesced particle dispersion to 100 mL of the electrolytic solution. 30,000 particles are measured, and the volume median particle size (D50) is determined from the particle size distribution.

[Toner particle size]
-Measuring machine: Coulter Multisizer III (Beckman Coulter, Inc.)
・ Aperture diameter: 50μm
・ Analysis software: Multisizer III version 3.51 (Beckman Coulter, Inc.)
・ Electrolyte: Isoton II (Beckman Coulter)
-Dispersion: Emulgen 109P (manufactured by Kao Corporation, polyoxyethylene lauryl ether, HLB: 13.6) is dissolved in the electrolyte so as to have a concentration of 5% by weight to obtain a dispersion.
-Dispersion condition: 10 mg of a measurement sample is added to 5 mL of the dispersion, and dispersed for 1 minute with an ultrasonic disperser, and then 25 mL of an electrolyte is added, and further dispersed for 1 minute with an ultrasonic disperser. A sample dispersion is prepared.
Measurement conditions: The sample dispersion is added to 100 mL of the electrolytic solution to adjust the particle size of 30,000 particles to a concentration that can be measured in 20 seconds, and then 30,000 particles are measured and the particle size distribution thereof. To determine the volume-median particle size (D50).

[Measurement of BET specific surface area]
A BET specific surface area was measured under the following conditions using Micromeritics FlowSorb III (manufactured by Shimadzu Corporation).
-Toner sample amount: about 0.1g
・ Deaeration condition: 40 ° C., 10 minutes ・ Adsorption gas: Nitrogen gas

[Measurement of circularity]
-Preparation of dispersion: 50 mg of toner was added to 5 ml of an aqueous polyoxyethylene lauryl ether solution (Kao Corporation, Emulgen 109P HLB 13.6, 5 wt% aqueous solution), and dispersed for 1 minute with an ultrasonic disperser, followed by distillation. 20 ml of water was added and further dispersed for 1 minute with an ultrasonic disperser to obtain a toner dispersion.
Measurement device: Flow-type particle image analyzer (FPIA-3000 manufactured by Sysmex Corporation)
・ Measurement mode: HPF measurement mode

Resin production example 1 (Production of polyester A)
Polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane 8,320 g, Polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane 80 g, terephthalic acid 1,592 g and dibutyltin oxide (esterification catalyst) 32 g Placed in a four-necked flask equipped with a nitrogen introduction tube, dehydration tube, stirrer and thermocouple at 230 ° C. under nitrogen atmosphere and normal pressure (101.3 kPa) The reaction was carried out for 5 hours, and further under reduced pressure. After cooling to 210 ° C., 1672 g of fumaric acid and 8 g of hydroquinone were added and reacted for 5 hours, and further reacted under reduced pressure to obtain polyester A. Polyester A had a softening point of 110 ° C., a glass transition point of 66 ° C., an acid value of 24.4 mgKOH / g, and a number average molecular weight of 3,760.

Resin production example 2 (Production of polyester B)
Polyoxypropylene (2.2) -2, 2-bis (4-hydroxyphenyl) propane 1750 g, polyoxyethylene (2.0) -2, 2-bis (4-hydroxyphenyl) prone 1625 g, terephthalic acid 1145 g, 161 g of dodecenyl succinic anhydride, 480 g of trimellitic anhydride and 26 g of tin 2-ethylhexanoate were placed in a four-necked flask equipped with a nitrogen inlet tube, a dehydrating tube, a stirrer, and a thermocouple. Stirring and reacting until the softening point measured in accordance with ASTM D36-86 reaches 120 ° C. yields polyester B. Polyester B had a softening point of 121 ° C., a glass transition point of 65 ° C., an acid value of 21 mgKOH / g, and a number average molecular weight of 3,390.

Resin particle dispersion production example 1 (Production of resin particle dispersion A)
In a 5 liter stainless steel kettle, 390 g of polyester A and 210 g of polyester B (when the polyester A and polyester B are mixed in the above ratio, the softening point of the mixed resin is 114 ° C., the glass transition point is 66 ° C., and the acid value is 23 mgKOH / g), 45 g of copper phthalocyanine pigment “ECB301 (manufactured by Dainichi Seika)” and anionic surfactant “Neopelex G-15 (manufactured by Kao): sodium dodecylbenzenesulfonate” (solid content: 15% by weight) ) 40 g, 6 g of the nonionic surfactant “Emulgen 430 (manufactured by Kao Corporation): polyoxyethylene (26 mol) oleyl ether (HLB 16.2)” and 279 g of 5 wt% aqueous potassium hydroxide solution with a chi-type stirrer The mixture was dispersed at 25 ° C. with stirring at 200 r / min. The contents were stabilized at 95 ° C. and held for 2 hours under stirring at 200 r / min with a chi-type stirrer. Subsequently, 1135 g of deionized water was added at 6 g / min while stirring at 200 r / min with a Kai-type stirrer. Further, the temperature in the system was maintained at 95 ° C. while deionized water was added dropwise. Then, the resin particle dispersion liquid which cooled to 25 degreeC and disperse | distributed the resin particle was obtained. The volume median particle size (D50) of the resin fine particles in the obtained resin particle dispersion was 0.17 μm, and the solid content concentration was 31.0% by weight.

  1200 g of the obtained resin particle dispersion is put into a 2 liter separable flask, and a polymer “WS700 (manufactured by Nippon Shokubai Co., Ltd.)” containing a water-soluble oxazoline group is stirred with a chi-type stirrer at 200 r / min. (Oxazoline group content in oxazoline polymer 4.6 mmol / g, number average molecular weight 20,000, aqueous solution solid content 25%) 16.6 g was added while maintaining the temperature of the aqueous solution at 25 ° C. Thereafter, the temperature was raised to 95 ° C. over 30 minutes and held for 1 hour after reaching 95 ° C. Then, it cooled to 25 degreeC and obtained the resin particle dispersion liquid A in which the crosslinked resin particle was disperse | distributed through the 150-mesh (mesh: 105 micrometers) wire mesh. The volume median particle size (D50) of the crosslinked resin particles in the obtained resin particle dispersion A is 0.18 μm, the softening point is 116 ° C., the glass transition point is 58 ° C., and the solid content concentration is 30.8% by weight. There was no resin component left on the wire mesh.

Resin particle dispersion production example 2 (Production of resin particle dispersion B)
In a 5 liter stainless steel kettle, 390 g of polyester A and 210 g of polyester B (when polyester A and polyester B are mixed in the above proportions, the softening point of the mixed resin is 114 ° C., the glass transition point is 66 ° C., and the acid value is 23 mg KOH. / G), and anionic surfactant “Neopelex G-15 (manufactured by Kao Corporation): sodium dodecylbenzenesulfonate” (solid content: 15% by weight) 40 g, nonionic surfactant “Emulgen 430 (Kao) 6 g of polyoxyethylene (26 mol) oleyl ether (HLB 16.2) ”and 279 g of a 5 wt% aqueous potassium hydroxide solution were dispersed at 25 ° C. with stirring at 200 r / min with a Kai-type stirrer. The contents were stabilized at 95 ° C. and held for 2 hours under stirring at 200 r / min with a chi-type stirrer. Subsequently, 1135 g of deionized water was added at 6 g / min while stirring at 200 r / min with a Kai-type stirrer. Further, the temperature in the system was maintained at 95 ° C. while deionized water was added dropwise. Then, it cooled to 25 degreeC and obtained the resin particle dispersion B in which the resin particle was disperse | distributed. The volume median particle size (D50) of the resin fine particles in the obtained resin particle dispersion B was 0.15 μm, the glass transition point was 58 ° C., the softening point was 105 ° C., and the solid content concentration was 33.5% by weight. It was.

Release agent dispersion production example 1 (Production of release agent dispersion A)
In a 1 liter beaker, 3.57 g of an aqueous solution of dipotassium alkenyl succinate “Latemul ASK (manufactured by Kao Corporation), solid content 28%” was dissolved in 400 g of deionized water, and then carnauba wax (manufactured by Kato Yoko Co., Ltd., melting point 85). 100 g) was dispersed. While maintaining the temperature at 90 to 95 ° C., the dispersion was subjected to a dispersion treatment with an Ultrasonic Homogenizer 600W (manufactured by Nippon Seiki Co., Ltd.) for 30 minutes to obtain a release agent dispersion A. The volume median particle size (D50) of the release agent in the obtained release agent dispersion A was 0.47 μm, and the solid content concentration was 21.4% by weight.

Example 1 (Production of Cyan Toner A)
[Process 1]
269 g of deionized water is added to 1200 g of the resin particle dispersion A, 10.9 g of deionized water is added to 181.7 g of the release agent dispersion A, and both are provided in four 10 liter units equipped with a dehydrating tube, a stirrer, and a thermocouple. Placed in a neck flask and mixed at room temperature. Next, an aqueous solution obtained by dissolving 87.1 g of ammonium sulfate (special grade made by Sigma-Aldrich Japan) in 776.4 g of deionized water was added dropwise to the mixture over 10 minutes at room temperature while stirring with a Kai-type stirrer (Ea : 3.5% by weight). Thereafter, the mixed dispersion is heated to 55 ° C. to form aggregated particles, and held at a temperature of 55 ° C. until the volume-median particle size (D50) of the aggregated particles becomes 4.2 μm. An agglomerated particle dispersion was obtained.

[Process 2]
The temperature of the aggregated particle dispersion obtained in step 1 is maintained at 55 ° C., and a mixture of 102.9 g of resin particle dispersion B and 44 g of deionized water is added dropwise to the aggregated particle dispersion at 1.9 g / min. After completion of dropping, the mixture was kept at 55 ° C. for 20 minutes. This operation was further repeated four times to prepare a dispersion of resin fine particle-attached aggregated particles having an aggregating agent concentration Eb of 2.7% by weight.

[Process 3]
Thereafter, an aqueous solution obtained by diluting 93.1 g of a polyoxyethylene (2 mol) sodium dodecyl ether sulfate aqueous solution (solid content: 28% by weight) with 7357 g of deionized water was added to reduce the coagulant concentration (Ec) in the system to 0. Adjusted to 81% by weight. At this time, the volume median particle size (D50) of the resin fine particle adhered aggregated particles was 4.7 μm.

[Process 4]
The resin fine particle-attached aggregated particle dispersion, in which the concentration of the flocculant in Step 3 was adjusted, was heated to 68 ° C. over 2 hours. Then, after hold | maintaining at 68 degreeC for 3 hours, it cooled to room temperature. During this time, the toner shape changed from the resin fine particle adhered aggregated particles to the coalesced particles. The volume-median particle size (D50) of the coalesced particles was 4.7 μm.

[Production of toner particles]
The dispersion containing the coalesced particles was subjected to a suction filtration step, a washing step, and a drying step to obtain colored resin particle powder. In the washing process, the dispersion containing coalesced particles is added to a centrifugal dehydrator (Centrifuge H-122 manufactured by KOKUSA), and removed while being centrifuged at a peripheral speed of 47 m / s (rotation speed 3000 rpm, diameter 30 cm). Washing was performed by mixing ionic water at a rate of 20 ± 1 L with respect to 100 g of the resin in the coalesced particles. Thereafter, the water content of the colored resin particle powder was further reduced by rotating for 1 hour, and then left in a vacuum dryer maintained at 40 ° C. to dry the colored resin particle powder to obtain toner particles.

[Production of toner]
To 100 parts by weight of the toner particles, 2.5 parts by weight of hydrophobic silica 1 (manufactured by Nippon Aerosil Co., Ltd .; RY50), 1.0 part by weight of hydrophobic silica 2 (manufactured by Cabot Corporation; Cabo Seal TS720), and organic fine particles ( Nippon Paint Co., Ltd. Finesphere P2000) 0.8 part by weight was externally added using a Henschel mixer to obtain cyan toner A. The volume-median particle size (D50) of cyan toner A was 4.7 μm.

Examples 2 to 5, 7 to 10 (production of cyan toners B, C, D, E, G, H, I, and J)
In step 3, the concentration of the flocculant in the system is adjusted to the concentration of the polyoxyethylene (2 mol) sodium dodecyl ether sodium sulfate solution to be added, that is, the amount of dilute water of polyoxyethylene (2 mol) sodium dodecyl ether sulfate. Thus, the cyan toner was adjusted in the same manner as in Example 1 except that the density described in Table 1 and Table 2 was adjusted, and the coalescence temperature and coalescence retention time were also set to the values described in Table 1 and Table 2. B, C, D, E, G, H, I and J were obtained, respectively.

Example 6 (Production of Cyan Toner F)
In step 2, the number of times the resin particle dispersion B is repeatedly added is changed from 4 times to 9 times, and in step 3, the concentration of the flocculant in the system is changed to that of the polyoxyethylene (2 mol) sodium dodecyl ether aqueous solution to be added. By adjusting the concentration, that is, the amount of dilute water of polyoxyethylene (2 mol) sodium dodecyl ether sulfate, the concentration is adjusted to the concentrations described in Table 1 and Table 2, and the coalescence temperature and coalescence retention time are also adjusted. A cyan toner F was obtained in the same manner as in Example 1 except that the values described in Table 1 were set.

Comparative Examples 1 to 6 (production of cyan toners K, L, M, N, O, and P)
In step 3, the concentration of the flocculant in the system is adjusted to the concentration of the polyoxyethylene (2 mol) sodium dodecyl ether sodium sulfate solution to be added, that is, the amount of dilute water of polyoxyethylene (2 mol) sodium dodecyl ether sulfate. In the same manner as in Example 1, except that the density described in Table 1 and Table 2 was adjusted, and the coalescence temperature and coalescence retention time were also set to the values described in Table 1 and Table 2. Toners K, L, M, N, O and P were obtained, respectively.

Each of the cyan toners A to P obtained as described above was evaluated as follows. The results are shown in Tables 1 and 2.

[Toner transferability]
The toner is mounted on a commercially available non-magnetic one-component development type printer (ML5400 manufactured by Oki Data Corporation), the machine is stopped while printing a solid image, and a transparent mending tape (Scotch (registered trademark) on the surface of the photoreceptor after transfer. ) Mending tape 810, manufactured by 3M Company, width: 18 mm) was attached.
A mending tape as a reference and a peeled tape were affixed on the surface of unused high-quality paper (Oki Data Co., Ltd., Excellent White Paper A4 size), and 10 sheets of the same paper were layered underneath.
The reference tape affixed using a colorimeter “SpectroEye” (Gretag-Macbeth, Inc., light conditions; standard light source D ₅₀ , observation field of view 2 °, absolute white standard) and the hue of the tape from which the transfer residual toner has been peeled are 3 Each place was measured to obtain an arithmetic average, and a color difference (ΔE) between them represented by the following formula was calculated. The smaller ΔE, the smaller the transfer residue, that is, the higher image quality can be reproduced. The results are shown in Table 1.
ΔE = [(L * ₁ −L * ₂ ) ² + (a * ₁ −a * ₂ ) ² + (b * ₁ −b * ₂ ) ² ] ^1/2
[In the formula, L ₁ , a ₁ and b ₁ are the measured values on the mending tape as a reference, and L ₂ , a ₂ and b ₂ are the measured values on the mending tape from which the toner on the photoconductor is sampled. Each value is shown. ]

[Toner chargeability]
Under an NN environment (25 ° C., 50% RH), 2.1 g of toner and 27.9 g of a silicone ferrite carrier (manufactured by Kanto Denka Kogyo Co., Ltd., average particle size: 40 μm) and a 50 cc cylindrical polypropylene bottle (manufactured by Nikko Corporation) ) And pre-stirred 10 times vertically and horizontally. Thereafter, the charge amount at a mixing time of 1 hour was measured using a tumbler mixer using a q / m meter (manufactured by EPPING) to obtain a charge amount in a NN environment (NN charge amount).
Measuring instrument: q / m-meter manufactured by EPPING
Setting:
Mesh size: 635 mesh (aperture: 24 μm, made of stainless steel)
Soft blow Blow pressure (600V)
Suction time: 90 seconds Charge amount (μC / g) = Total amount of electricity after 90 seconds (μC) / Amount of toner sucked (g)
The developer after measurement is placed in an HH environment (30 ° C., 85% RH) and held for 12 hours. Thereafter, the developer taken out from the HH environment was further stirred for 1 hour with a tumbler mixer and then measured to obtain a charge amount in the HH environment (HH charge amount).
(Criteria for determining the absolute value of charge amount)
40 to less than 50 is good 30 to less than 40 is actual use level Less than 30 is bad

[Toner charge amount retention]
Using the charge amount under each environment, the retention rate of the charge amount was calculated according to the following formula.
Charge amount retention rate (%) = (charge amount in HH environment / charge amount in NN environment) × 100
A battery with a charge retention rate close to 100% was evaluated as good.

[Evaluation method of scattering properties]
Under an NN environment (25 ° C., 50% RH), 0.7 g of toner and 9.3 g of a silicone ferrite carrier (manufactured by Kanto Denka Kogyo Co., Ltd., average particle size: 40 μm) and 20 cc cylindrical polypropylene bottle (Nikko Corporation) ) And stirred with shaking 10 times vertically and horizontally. Then, it stirred for 10 minutes with the ball mill. A developing roller (diameter 42 mm) mounted on a commercially available printer was taken out and modified to be variable in rotation (external developing roller device). The current roller of the external developing roller device was rotated at a speed of 10 revolutions / minute, and the developer was deposited on the developing roller so as to have a width of 3 to 8 cm. After uniformly attaching, the rotation was once stopped. The rotation number of the developing roller was changed to 45 rotations / minute, and the number of scattered toner particles when rotated for 1 minute was measured with DIGITAL DUST INDICATOR MODEL P-5 (manufactured by SIBATA SCIENTIFIC TECHNOLOGY LTD).
The toner scattering property was evaluated from the number of scattered toner particles. The scattering property indicates that the smaller the toner scattering particle number, the better.

[Evaluation of storage stability of toner]
10 g of toner was placed in a 20 ml internal volume plastic bottle and allowed to stand in an open state for 48 hours in an environment of a temperature of 55 ° C. and a relative humidity of 40 RH%. After standing, the aggregation degree was measured with a powder tester (manufactured by Hosokawa Micron Corporation), and the storage stability of the toner was evaluated according to the following criteria.
The smaller the degree of aggregation, the better the storage stability of the toner.
A: The degree of aggregation is less than 10%.
B: The degree of aggregation is 10% or more and less than 20%.
C: The degree of aggregation is 20% or more.
In addition, the aggregation degree using a powder tester was specifically determined as follows.
Three different sieve openings are set in the order of 250 μm in the upper stage, 150 μm in the middle stage, and 75 μm in the lower stage on the powder tester's shaking table, and 2 g of toner is placed on the shaker for 60 seconds, and the remaining toner weight on each sieve. Measure.
The measured toner weight is applied to the following equation and calculated to obtain the degree of aggregation [%].
Aggregation degree [%] = a + b + c
a = (weight of residual toner on upper stage) / 2 [g] × 100
b = (middle stage residual toner weight) / 2 [g] × 100 × (3/5)
c = (lower stage residual toner weight) / 2 [g] × 100 × (1/5)

  According to the production method of the present invention, it is easy to design a toner according to various uses. Therefore, the toner of the present invention is used for electrophotography, electrostatic recording method, electrostatic printing method and the like. It can be suitably used for a toner.

Claims (5)

(1) Step 1 of adding a flocculant to the resin particle dispersion so as to have a flocculant concentration Ea (% by weight) to aggregate the resin particles in the resin particle dispersion to obtain an agglomerated particle dispersion;
(2) Step 2 of adding a resin fine particle dispersion to the aggregated particle dispersion obtained in Step 1 to obtain a resin fine particle-attached aggregated particle dispersion having a coagulant concentration Eb satisfying the following formula 1:
0.60 ≦ Eb / Ea <1 (1)
(3) Step 3 of adjusting the coagulant concentration of the dispersion of the resin fine particle-adhered aggregated particles obtained in Step 2 to a coagulant concentration Ec satisfying the following formula 2, and 0.005 ≦ Ec / Ea ≦ 0.30 2)
(4) The resin fine particle adhered aggregated particles in the dispersion of the resin fine particle adhered aggregated particles having the coagulant concentration Ec obtained in the step 3 are equal to or higher than the glass transition point Tg (° C.) of the resin fine particles in the resin fine particle dispersion. And (4) heating and coalescing at a temperature of (Tg + 20) ° C. or lower,
A method for producing an electrophotographic toner comprising: The flocculant concentration Ec in step 3 is expressed by the formula 0.08 <Ec / Ea ≦ 0.30 (2-1)
The method for producing an electrophotographic toner according to claim 1, wherein: The flocculant concentration Ec in step 3 is expressed by the formula 0.005 ≦ Ec / Ea ≦ 0.08 (2-2)
The method for producing an electrophotographic toner according to claim 1, wherein:   The method for producing an electrophotographic toner according to claim 1, wherein both the resin particles in the resin particle dispersion and the resin particles in the resin particle dispersion contain polyester. Furthermore, in the process 3, the manufacturing method of the toner for electrophotography in any one of Claims 1-4 which has the process of adding the aggregation stopper represented by following formula (3).
R—O— (CH ₂ CH ₂ O) nSO ₃ M (3)
(In the formula, R represents an alkyl group, M represents a monovalent cation, and n represents an average addition mole number of 0 to 15.)