JP6007078B2 - Method for producing toner for electrophotography - Google Patents

Description

  The present invention relates to a method for producing an electrophotographic toner and an electrophotographic toner obtained thereby.

In the field of electrophotographic toner, with development of an electrophotographic system, development of a toner corresponding to high image quality and high speed is required.
From the viewpoint of high image quality, it is necessary to reduce the particle size of the toner, and so-called chemical toners obtained by chemical methods such as a polymerization method and an emulsifying dispersion method have been proposed instead of the conventional melt-kneading method. Furthermore, from the viewpoint of speeding up, a release agent is used in order to improve the low-temperature fixability and widen the fixable temperature range, thereby reducing the power consumption of the printing press and making the toner suitable for high-speed printing. An attached chemical toner has been reported. However, unlike the melt kneading and pulverizing method, there is no kneading step in the chemical method, so the cohesiveness between the release agent and the resin particles and the dispersibility of the release agent in the toner are not sufficient.

In order to improve this point, for example, Patent Document 1 discloses a mold release agent (A), a mold release agent (B) having a melting point higher by 5 ° C. than the melting point of the mold release agent (A), and poly A method for producing a toner is disclosed in which a carboxylate is dispersed in an aqueous medium to obtain release agent particles, and the release agent particles and resin particles are aggregated and united. According to the manufacturing method, it is said that release of the release agent is reduced during the coalescence process.
Patent Document 2 discloses an electrostatic latent image developing toner comprising toner particles containing at least a binder resin and a colorant and an external additive, and the external additive has a specific melting point inside. An electrostatic latent image developing toner containing inorganic particles and / or resin particles containing a mold is disclosed.

International Publication No. 2011/074580 JP 2006-235383 A

However, depending on the type of the release agent, the affinity with the resin particles is low and the aggregation property is not sufficient, but even if aggregation is possible, the release agent particles are separated from the aggregated particles during the fusing step after the aggregation step. As a result, the charging characteristics are deteriorated.
An object of the present invention is to provide a method for producing an electrophotographic toner having a wide fixing temperature range and excellent charging characteristics, and an electrophotographic toner obtained thereby.

  In agglomerating the release agent and the resin particles, the present inventors previously prepared and agglomerated the release agent particles containing a specific amount of inorganic fine particles, thereby solving the above-mentioned problems and increasing the wide fixing temperature range. It has been found that an electrophotographic toner having an excellent charging property can be obtained.

That is, the present invention provides the following [1] and [2].
[1] A method for producing an electrophotographic toner comprising the steps (1) to (4).
Step (1): Step of preparing release agent particles containing wax and inorganic fine particles Step (2): Release agent particles obtained in Step (1), resin particles (A), and aggregating agent, Step of obtaining aggregated particles (1) by mixing in an aqueous medium Step (3): Step of adding resin particles (B) to an aqueous medium containing aggregated particles (1) to obtain aggregated particles (2) 4) Step of fusing the aggregated particles (2) to obtain fused particles [2] An electrophotographic toner obtained by the production method described in [1] above.

According to the present invention, it is possible to control aggregation during toner production with a small particle size, that is, to generate aggregate particles having a sharp particle size distribution, and for electrophotography with little release agent release and surface exposure during the fusing process. A toner production method can be provided.
In addition, according to the present invention, a method for producing an electrophotographic toner having a wide fixing temperature range and excellent charging characteristics, and an electrophotographic toner obtained thereby can be provided.

The method for producing the electrophotographic toner of the present invention includes:
Step (1): Step of preparing release agent particles containing wax and inorganic fine particles Step (2): Release agent particles obtained in Step (1), resin particles (A), and aggregating agent, Step of obtaining aggregated particles (1) by mixing in an aqueous medium Step (3): Step of adding resin particles (B) to an aqueous medium containing aggregated particles (1) to obtain aggregated particles (2) 4): A step of fusing the agglomerated particles (2) to obtain fused particles.

The reason why the electrophotographic toner obtained by the production method of the present invention exhibits a wide fixable temperature range and is excellent in charging characteristics is not clear, but can be considered as follows.
In general, the specific gravity of the wax is smaller than that of the aqueous medium. Therefore, even if the resin particles and the release agent particles are aggregated in the aqueous medium in the aggregation process, the wax is not easily taken into the aggregate of resin particles. Even if it is taken in, it is easy to separate from the agglomerated particles. On the other hand, by using release agent particles in which wax and inorganic fine particles are mixed in advance, the specific gravity of the release agent particles is increased, and the floating of the release agent particles in the aqueous medium is suppressed. As a result, the specific gravity difference in the aggregation process is corrected, the release agent particles are easily taken into the aggregate of resin particles by stirring and mixing, and the incorporated release agent particles are difficult to separate from the aggregated particles. Become. As a result, it becomes possible to obtain agglomerated particles in which the wax is efficiently incorporated, so that the wax inclusion rate in the toner particles is improved, the fixable temperature range of the obtained toner is expanded, and the charging characteristics are improved. It is done.
Hereinafter, each component and process used in the present invention will be described.

<Step (1)>
Step (1) in the method for producing an electrophotographic toner of the present invention is a step of preparing release agent particles containing a wax and inorganic fine particles.

[Releasing agent particles]
In the present invention, the release agent particles are preferably obtained as a dispersion of release agent particles by dispersing wax and inorganic fine particles in an aqueous medium.

(wax)
Examples of waxes include low molecular weight polyolefins such as polyethylene, polypropylene and polybutene; silicones having a softening point upon heating; fatty acid amides such as oleic acid amide and stearic acid amide; carnauba wax, rice wax, and candelilla wax. Plant waxes; animal waxes such as beeswax; mineral and petroleum waxes such as montan wax, paraffin wax, and Fischer-Tropsch wax. These waxes can be used alone or in combination of two or more. Among these, paraffin wax is preferable from the viewpoint of improving the releasability of the obtained toner, widening the fixable temperature range, and improving the chargeability.
The melting point of the wax is preferably 100 ° C. or lower, more preferably 90 ° C. or lower, and more preferably 85 ° C. or lower from the viewpoint of improving the low-temperature fixability of the toner obtained, the viewpoint of widening the fixable temperature range, and the viewpoint of improving the chargeability. Is more preferable, 80 ° C. or lower is further preferable, 50 ° C. or higher is preferable, 60 ° C. or higher is more preferable, 65 ° C. or higher is further preferable, and 70 ° C. or higher is even more preferable.
In the present invention, the melting point of the wax is determined by the method described in the examples. When two or more kinds are used in combination, the melting point of the wax in the present invention is the melting point of the wax having the largest mass ratio among the waxes contained in the obtained toner. When all have the same ratio, the lowest value is set.
The amount of the wax added is that the resin particles (A) and the resin particles (B) in the toner are added from the viewpoint of improving the releasability of the obtained toner, widening the fixable temperature range, and improving the charging property. 20 parts by mass or less is preferable, 15 parts by mass or less is more preferable, 10 parts by mass or less is more preferable, 1 part by mass or more is preferable, and 3 parts by mass or more is more preferable. 5 parts by mass or more is more preferable.

(Inorganic fine particles)
In the present invention, the release agent particles are characterized by containing inorganic fine particles. By using inorganic fine particles that have a higher specific gravity than wax, the specific gravity difference between the aqueous medium and the release agent particles in the aggregation process is corrected, so that the release agent particles in the aggregate of resin particles by stirring and mixing. Is likely to be taken in, and the taken-in release agent particles are considered difficult to separate from the aggregated particles.

  Examples of the inorganic fine particles include silicon dioxide (silica), titanium oxide, aluminum oxide, zinc oxide, magnesium oxide, cerium oxide, iron oxide, tin oxide, and the like, and a viewpoint of obtaining uniform aggregated particles in the subsequent aggregation process, and From the viewpoint of improving the chargeability of the obtained toner, at least one selected from silica, titanium oxide, and aluminum oxide is preferable, at least one selected from silica and titanium oxide is more preferable, and silica is more preferable. Moreover, you may use an inorganic fine particle individually or in mixture of 2 or more types.

  As the inorganic fine particles, those having a hydrophobic surface are preferable from the viewpoint of affinity for wax. For example, silica is hydrophobized with silica hydrophobized with at least one treatment agent selected from silicone oil, dimethyldichlorosilane and hexamethyldisilazane, and organopolysiloxane having a nitrogen atom in the side chain. Silica that has been hydrophobized with silicone oil, dimethyldichlorosilane (DMDS) and hexamethyldisilazane (HMDS) is more preferred from the viewpoint of improving the affinity for wax.

The average primary particle diameter of the inorganic fine particles is preferably 90 nm or less, from the viewpoint of improving the dispersion stability of the release agent particles, from the viewpoint of widening the fixable temperature range of the obtained toner, and from the viewpoint of improving the chargeability, and is preferably 50 nm or less. Is more preferable, 30 nm or less is still more preferable, and 20 nm or less is still more preferable. Moreover, 5 nm or more is preferable, 8 nm or more is more preferable, and 12 nm or more is still more preferable.
The specific gravity of the inorganic fine particles is preferably 5 or less, and preferably 4.5 or less from the viewpoint of improving the dispersion stability of the release agent particles, from the viewpoint of widening the fixable temperature range of the obtained toner, and from the viewpoint of improving the chargeability. More preferably, 3.5 or less is still more preferable, and 3.0 or less is still more preferable. Moreover, 1.3 or more are preferable, 1.5 or more are more preferable, and 2.0 or more are still more preferable.

  The mass ratio of the wax and the inorganic fine particles in the release agent particles (the mass of the wax / the mass of the inorganic fine particles) is obtained from the viewpoint of reducing the amount of the free inorganic fine particles and obtaining uniform agglomerated particles in the subsequent aggregation step. From the viewpoint of widening the fixable temperature range of the toner and improving the chargeability, 95/5 to 50/50 is preferable, 95/5 to 60/40 is more preferable, and 90/10 to 70/30 is still more preferable. 85/15 to 75/25 are even more preferable.

(Manufacture of release agent particles)
The release agent particles are preferably obtained as a dispersion of release agent particles by dispersing wax and inorganic fine particles in an aqueous medium. The release agent particles are more preferably dispersed in an aqueous medium at a temperature equal to or higher than the melting point of the wax in the presence of a surfactant in the aqueous medium.

Moreover, it is preferable to disperse the release agent particles using a disperser.
As the disperser to be used, a homogenizer, a high-pressure disperser, an ultrasonic disperser, and the like are preferable, and a high-pressure disperser is more preferable from the viewpoint of widening the fixable temperature range of the obtained toner and improving the chargeability. What is necessary is just to set dispersion | distribution time suitably with the disperser to be used.
Examples of the high-pressure disperser include a high-pressure wet atomizer, and examples of commercially available devices include “Nanomizer” (manufactured by Yoshida Kikai Kogyo Co., Ltd.).
As an ultrasonic disperser, an ultrasonic homogenizer is mentioned, for example, As a commercially available apparatus, "US-600T" (Nippon Seiki Co., Ltd.) is mentioned.
Further, before using the disperser, the wax, the inorganic fine particles, and optionally the surfactant and / or the aqueous medium may be preliminarily dispersed in a mixer such as a homomixer or a ball mill in advance. preferable.

As the aqueous medium, those containing water as a main component are preferable. From the viewpoint of environmental properties and the viewpoint of improving the dispersion stability of the release agent particles, the content of water in the aqueous medium is preferably 80% by mass or more. More preferably, it is more preferably 95% by mass or more, still more preferably 95% by mass or more, still more preferably 100% by mass, and even more preferably 100% by mass. As water, deionized water or distilled water is preferably used.
As a component of the aqueous medium other than water, an organic solvent that dissolves in water such as an alkyl alcohol having 1 to 5 carbon atoms; a dialkyl ketone having 1 to 3 carbon atoms such as acetone and methyl ethyl ketone; and a cyclic ether such as tetrahydrofuran is used. In the case of using an organic solvent, among these, from the viewpoint of preventing the organic solvent from being mixed into the toner, an alkyl alcohol having 1 to 5 carbon atoms that does not dissolve the polyester resin is preferable, and methanol, ethanol, isopropanol, and butanol are more preferable. .

  The dispersion of the release agent particles in the aqueous medium is performed in the presence of a surfactant from the viewpoint of improving the dispersion stability of the release agent particles and obtaining uniform aggregated particles in the subsequent aggregation step. preferable.

  Examples of the surfactant include nonionic surfactants, anionic surfactants, and cationic surfactants. Among them, in terms of improving the dispersion stability of the release agent particles, and in the subsequent aggregation step From the viewpoint of obtaining uniform aggregated particles, an anionic surfactant is preferred.

The anionic surfactant is preferably at least one selected from the group consisting of aliphatic carboxylates, alkylbenzene sulfonates, alkyl sulfates, and alkyl ether sulfates. As a kind of salt, at least 1 sort (s) chosen from the group which consists of sodium salt, potassium salt, and ammonium salt is preferable.
Specific examples of the anionic surfactant include sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, sodium lauryl ether sulfate, dipotassium alkenyl succinate, and the like, from the viewpoint of improving the dispersion stability of the release agent particles. Alkyl alkenyl succinate is preferred.
In addition, as an anionic surfactant, a polymer compound having a carboxyl group salt in the side chain, such as sodium poly (meth) acrylate, sodium (meth) acrylate-sodium maleate copolymer, and the like is also preferably used. Can do.
The nonionic surfactant includes at least one selected from the group consisting of polyoxyethylene alkyl aryl ethers, polyoxyethylene alkyl or alkenyl ethers, polyoxyethylene fatty acid esters, and oxyethylene / oxypropylene block copolymers. preferable.
Specific examples of the polyoxyethylene alkylaryl ethers include polyoxyethylene nonylphenyl ether. Specific examples of polyoxyethylene alkyl or alkenyl ethers include polyoxyethylene oleyl ether and polyoxyethylene lauryl ether. Specific examples of polyoxyethylene fatty acid esters include polyethylene glycol monolaurate, polyethylene glycol monostearate, polyethylene glycol monooleate, and the like.
Specific examples of the cationic surfactant are preferably quaternary ammonium salts such as alkylbenzenedimethylammonium chloride and alkyltrimethylammonium chloride.

  The content of the surfactant is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, with respect to 100 parts by mass of the total amount of wax and inorganic fine particles, from the viewpoint of improving the dispersion stability of the release agent particles. 10 parts by mass or less is more preferable, 5 parts by mass or less is more preferable, 0.1 part by mass or more is preferable, 0.5 part by mass or more is more preferable, 1 part by mass or more is further preferable, 1.5 Part by mass or more is even more preferable.

The volume median particle size (D ₅₀ ) of the release agent particles is preferably 1 μm or less from the viewpoint of obtaining uniform aggregated particles in the subsequent aggregation process and improving the chargeability of the obtained toner, and is preferably 0.70 μm. The following is more preferable, 0.60 μm or less is further preferable, 0.55 μm or less is further preferable, 0.10 μm or more is preferable, 0.30 μm or more is more preferable, 0.40 μm or more is further preferable, and 0.45 μm. The above is more preferable, and 0.48 μm or more is even more preferable.
The CV value of the release agent particles is preferably 60% or less, more preferably 55% or less, still more preferably 50% or less, more preferably 20% or more, from the viewpoint of improving the chargeability of the obtained toner. % Or more is more preferable, 40% or more is further preferable, and 45% or more is further more preferable. The volume median particle size (D ₅₀ ) and CV value of the release agent particles are specifically determined by the method described in the examples.

  The solid content concentration of the release agent particle dispersion is preferably 50% by mass or less, more preferably 40% by mass or less from the viewpoint of improving the dispersion stability of the release agent particles and facilitating handling. 30 mass% or less is still more preferable, 7 mass% or more is preferable, and 10 mass% or more is more preferable.

<Step (2)>
In the step (2) in the method for producing an electrophotographic toner of the present invention, the dispersion of the release agent particles obtained in the step (1), the resin particles (A), and the flocculant are mixed in an aqueous medium. In this step, the aggregated particles (1) are obtained by aggregation.

[Resin particles (A)]
(Polyester resin)
The resin particles (A) in the present invention contain a polyester resin from the viewpoint of improving the low-temperature fixability of the toner. As the polyester resin, a polyester resin having an acid group is preferably used. From the viewpoint of improving the emulsifiability of the resin during toner production, a polyester resin having an acid group at the end of the molecular chain is more preferable. Examples of the acid group include a carboxy group, a sulfonic acid group, a phosphonic acid group, and a sulfinic acid group. Among these, a carboxy group is preferable from the viewpoint of improving the emulsifiability of the resin at the time of toner production and improving the storage stability of the obtained toner.

  The content of the polyester resin in the resin of the resin particles (A) is preferably 80% by mass or more, and 90% by mass or more of the resin from the viewpoint of improving the low-temperature fixability of the toner and widening the fixable temperature range. More preferably, it is more preferably 95% by mass or more, substantially more preferably 100% by mass, and still more preferably 100% by mass.

The raw material monomer of the polyester resin is not particularly limited, and an arbitrary alcohol component and an arbitrary carboxylic acid component such as carboxylic acid, carboxylic acid anhydride, or carboxylic acid ester are used.
Examples of the acid component include dicarboxylic acids, trivalent or higher polyvalent carboxylic acids, acid anhydrides thereof, and alkyl esters having 1 to 3 carbon atoms. Among them, dicarboxylic acids are preferable.
Specific examples of the dicarboxylic acid include aromatic dicarboxylic acid and aliphatic dicarboxylic acid. Examples of the aromatic dicarboxylic acid include phthalic acid, isophthalic acid, terephthalic acid and the like. As aliphatic dicarboxylic acid, it was substituted with sebacic acid, fumaric acid, maleic acid, adipic acid, azelaic acid, succinic acid, cyclohexanedicarboxylic acid, alkyl group having 1 to 20 carbon atoms or alkenyl group having 2 to 20 carbon atoms. And succinic acid. Specific examples of the succinic acid substituted with an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms include dodecyl succinic acid, dodecenyl succinic acid, octenyl succinic acid, and the like. Among these, at least one selected from fumaric acid, terephthalic acid, dodecenyl succinic acid and acid anhydrides thereof is preferable.
Specific examples of the trivalent or higher polyvalent carboxylic acid include trimellitic acid, 2,5,7-naphthalenetricarboxylic acid, pyromellitic acid and the like. Among them, the viewpoint of improving the low-temperature fixability of the toner and hot resistance From the viewpoint of improving the offset property, trimellitic acid and its acid anhydride are preferable, and trimellitic acid anhydride is more preferable.
An acid component can be used individually or in combination of 2 or more types.

Examples of the alcohol component include aliphatic diols having 2 to 12 carbon atoms in the main chain, aromatic diols, alicyclic diols, trihydric or higher polyhydric alcohols, or alkylene oxides having 2 to 4 carbon atoms (average added mole number). 1-16) Additives and the like.
Preferred examples of the alcohol component include 2 carbon atoms of bisphenol A such as polyoxypropylene-2,2-bis (4-hydroxyphenyl) propane and polyoxyethylene-2,2-bis (4-hydroxyphenyl) propane. -3 alkylene oxide (average addition mole number 1-16) adduct, alicyclic diol such as hydrogenated bisphenol A or their alkylene oxides having 2 to 4 carbon atoms (average addition mole number 1-16), Aliphatic diols having 2 to 12 carbon atoms in the main chain such as ethylene glycol, propylene glycol, neopentyl glycol, 1,4-butanediol, 1,3-butanediol, 1,6-hexanediol, or those carbon numbers of 2 4 alkylene oxide (average added mole number 1-16) adduct, glycerin, pentaerythridine Lithol, trimethylolpropane, tri- or more polyhydric alcohols or their alkylene oxide having 2 to 4 carbon atoms (average addition molar number of 1 to 16) adduct of sorbitol. You may use the said alcohol component in combination of 2 or more type. Examples of the alcohol component include polyoxypropylene-2,2-bis (4-hydroxyphenyl) propane and polyoxyethylene-2,2-bis (4-hydroxyphenyl) propane from the viewpoint of improving the charging property of the toner. A C2-C3 alkylene oxide (average addition mole number 1-16) adduct of bisphenol A is preferable.

Polyester can be produced, for example, by polycondensing the alcohol component and the carboxylic acid component at a temperature of about 180 to 250 ° C. in an inert gas atmosphere, if necessary, using an esterification catalyst. it can.
As the esterification catalyst, an esterification catalyst such as a tin compound such as dibutyltin oxide or di (2-ethylhexanoic acid) tin or a titanium compound such as titanium diisopropylate bistriethanolamate can be used.
Although there is no restriction | limiting in the usage-amount of an esterification catalyst, 0.01-1 mass part is preferable with respect to 100 mass parts of total amounts of an acid component and an alcohol component, and 0.1-0.8 mass part is more preferable.
Examples of the polymerization inhibitor include tert-butylcatechol. The amount of the polymerization inhibitor used is preferably 0.001 to 0.5 parts by mass and more preferably 0.005 to 0.1 parts by mass with respect to 100 parts by mass of the total amount of the acid component and the alcohol component.

As the polyester resin in the resin particles (A), either crystalline polyester or amorphous polyester can be used, and both can be used in combination. From the viewpoint of widening, it is preferable to contain an amorphous polyester. 80-100 mass% is preferable, as for content of the amorphous polyester in the polyester resin in the resin particle (A), 90-100 mass% is more preferable, 95-100 mass% is still more preferable, and substantially 100 mass. % Is more preferable, and 100% by mass is even more preferable.
When the crystalline polyester and the amorphous polyester are mixed and used, the mass ratio of the crystalline polyester to the amorphous polyester (crystalline polyester / amorphous polyester) is determined from the viewpoint of improving the low-temperature fixability of the toner. From the viewpoint of improving the stability and the hot offset resistance, the ratio is preferably 1/99 to 50/50, more preferably 5/95 to 20/80.

  Here, the crystallinity of the resin is defined by the ratio between the softening point and the maximum endothermic peak temperature measured by a differential scanning calorimeter (DSC), that is, (softening point (° C)) / (maximum endothermic peak temperature (° C)). Expressed by the crystallinity index. The crystalline resin has a crystallinity index of 0.6 to 1.4, preferably 0.8 to 1.3, and more preferably 0.9 to 1.2. The amorphous resin is a resin having a crystallinity index of more than 1.4 or less than 0.6, and from the viewpoint of improving the low-temperature fixability of the toner and improving heat-resistant storage stability, it is less than 0.6 or It is preferably more than 1.4 and 4 or less, more preferably less than 0.6 or 1.5 or more and 4 or less, still more preferably less than 0.6 or 1.5 or more and 3 or less, and still more preferably 0.6. Less than or 1.5 or more and 2 or less. The crystallinity index can be appropriately determined according to the production conditions such as the type and ratio of the raw material monomers, the reaction temperature, the reaction time, and the cooling rate. The maximum endothermic peak temperature refers to the temperature of the peak on the highest temperature side among the observed endothermic peaks. The maximum peak temperature is the melting point if the difference from the softening point is within 20 ° C., and the peak due to the glass transition if the difference from the softening point exceeds 20 ° C.

  The softening point of the polyester resin is preferably 165 ° C. or lower, more preferably 140 ° C. or lower, still more preferably 130 ° C. or lower, and 125 ° C. or lower from the viewpoint of improving the low-temperature fixability of the toner and widening the fixable temperature range. Is more preferably 70 ° C. or higher, more preferably 80 ° C. or higher, still more preferably 90 ° C. or higher, and still more preferably 100 ° C. or higher.

The glass transition temperature of the polyester resin is preferably 80 ° C. or less, more preferably 70 ° C. or less, still more preferably 67 ° C. or less, from the viewpoint of improving the low-temperature fixability of the toner and widening the fixable temperature range. 50 degreeC or more is preferable, 53 degreeC or more is more preferable, and 55 degreeC or more is still more preferable. The glass transition temperature is a physical property unique to an amorphous resin.
The amount of acid groups at the end of the molecular chain of the polyester resin, that is, the acid value of the polyester resin is based on the viewpoint of improving the emulsifiability of the resin during the production of the toner, the viewpoint of widening the fixable temperature range of the toner, and the viewpoint of improving the chargeability. Therefore, 35 mgKOH / g or less is preferable, 30 mgKOH / g or less is more preferable, 25 mgKOH / g or less is more preferable, 5 mgKOH / g or more is preferable, 10 mgKOH / g or more is more preferable, and 15 mgKOH / g or more is more preferable. The desired softening point and acid value can be obtained by adjusting the charging ratio of alcohol and carboxylic acid, the temperature of condensation polymerization, and the reaction time.

  In the present invention, the polyester resin includes not only an unmodified polyester as long as it has an acid group, but also a polyester modified to such an extent that the properties 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 particle (A) contains a plurality of resins including a polyester resin having an acid group, the softening point, glass transition temperature, and acid value of the resin constituting the resin particle (A) are as follows. Means a softening point, a glass transition temperature, and an acid value as a mixture, and each value is preferably within the range of each characteristic of the polyester resin. The softening point, glass transition temperature, and acid value as a mixture can be determined by the weighted average of each value, that is, the sum of the product of the characteristic value and the content ratio of each resin.
Furthermore, when the polyester resin is contained, the resin constituting the resin particles (A) can contain two types of polyester resins having different softening points, and the low temperature fixability of the toner is improved. From the viewpoint of increasing the width and resistance to hot offset, the softening point of one polyester (I) is preferably 70 ° C. or higher and lower than 115 ° C., and the softening point of the other polyester (II) is 115 ° C. or higher and 165 ° C. or lower. Is preferred. The difference in softening point between the two types of polyester resins is preferably 5 ° C. or higher, more preferably 10 ° C. or higher, more preferably 30 ° C. or lower, and more preferably 20 ° C. or lower from the same viewpoint. The mass ratio (I / II) between the polyester (I) and the polyester (II) is preferably 10/90 to 90/10 from the viewpoint of improving the low-temperature fixability of the toner and widening the fixable temperature range. 10 / 90-50 / 50 is more preferable.

  The resin particles (A) may contain a resin other than the polyester resin, for example, a resin such as a styrene-acrylic copolymer, an epoxy resin, a polycarbonate, and a polyurethane as long as the effects of the present invention are not impaired.

(Surfactant)
The dispersion of the resin particles (A) in the present invention contains a surfactant from the viewpoint of improving the emulsifiability of the resin during toner production.

Examples of the surfactant include nonionic surfactants, anionic surfactants, and cationic surfactants. Among them, nonionic surfactants are preferable, and nonionic surfactants and anionic surfactants are preferred. It is more preferable to use an active agent or a cationic surfactant in combination, and from the viewpoint of improving the emulsifiability of the resin during toner production, it is further preferable to use a nonionic surfactant and an anionic surfactant in combination. preferable.
When a nonionic surfactant and an anionic surfactant are used in combination, the mass ratio of the nonionic surfactant to the anionic surfactant (nonionic surfactant / anionic surfactant) is: From the viewpoint of improving the emulsifiability of the resin during toner production, 0.3 to 10 is preferable, 0.5 to 5 is more preferable, and 0.8 to 1.5 is still more preferable.

The nonionic surfactant includes at least one selected from the group consisting of polyoxyethylene alkyl aryl ethers, polyoxyethylene alkyl or alkenyl ethers, polyoxyethylene fatty acid esters, and oxyethylene / oxypropylene block copolymers. preferable.
Specific examples of polyoxyethylene alkyl aryl ethers include polyoxyethylene nonylphenyl ether, and specific examples of polyoxyethylene alkyl or alkenyl ethers include polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, and the like. Is mentioned. Specific examples of polyoxyethylene fatty acid esters include polyethylene glycol monolaurate, polyethylene glycol monostearate, polyethylene glycol monooleate, and the like. As the nonionic surfactant, polyoxyethylene alkyl or alkenyl ethers are preferable, and polyoxyethylene oleyl ether is more preferable, from the viewpoint of improving the emulsifiability of the resin during toner production.
The anionic surfactant is preferably at least one selected from the group consisting of alkylbenzene sulfonates, alkyl sulfates, and alkyl ether sulfates. As a kind of salt, at least 1 sort (s) chosen from the group which consists of sodium salt, potassium salt, and ammonium salt is preferable.
Specific examples of the anionic surfactant include sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, sodium lauryl ether sulfate, and the like. From the viewpoint of improving the emulsifiability of the resin during toner production, sodium dodecyl benzene sulfonate, Sodium lauryl ether sulfate is preferred, and sodium dodecylbenzenesulfonate is more preferred.
Specific examples of the cationic surfactant are preferably quaternary ammonium salts such as alkylbenzenedimethylammonium chloride and alkyltrimethylammonium chloride.

  From the viewpoint of improving the storage stability of the toner, the content of the surfactant is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, with respect to 100 parts by mass of the resin constituting the resin particles (A). Less than or equal to 5 parts by weight is more preferred, and less than or equal to 5 parts by weight is even more preferred. Moreover, from a viewpoint of improving the emulsifiability of resin, 0.1 mass part or more is preferable with respect to 100 mass parts of resin which comprises resin particle (A), 0.5 mass part or more is more preferable, 1 mass part The above is more preferable.

  The resin particles (A) may contain a colorant, a release agent, and a charge control agent as long as the effects of the present invention are not impaired. Moreover, you may contain additives, such as reinforcement fillers, such as a fibrous material, antioxidant, and anti-aging agent, as needed.

(Coloring agent)
The resin particles (A) may be particles composed only of a resin or may be colorant-containing resin particles containing a colorant, but are colored from the viewpoint of obtaining uniform aggregated particles in a subsequent aggregation step. It is preferable that a colorant-containing resin particle containing a colorant is preferable.
When the resin particles (A) are colorant-containing resin particles, the content of the colorant is the resin 100 constituting the resin particles (A) from the viewpoint of improving the toner image density and improving the low-temperature fixability. 1 mass part or more is preferable with respect to a mass part, 5 mass parts or more are more preferable, 20 mass parts or less are preferable, and 10 mass parts or less are more preferable.

As the colorant, pigments and dyes are used, and pigments are preferable from the viewpoint of improving the image density of the toner.
Specific examples of the pigment include carbon black, inorganic composite oxide, benzidine yellow, brilliantamine 3B, brilliantamine 6B, bengal, aniline blue, ultramarine blue, copper phthalocyanine, and phthalocyanine green. Among these, copper Phthalocyanine is preferred.
Specific examples of the dye include acridine series, azo series, benzoquinone series, azine series, anthraquinone series, indico series, phthalocyanine series, and aniline black series.
A coloring agent can be used individually by 1 type or in combination of 2 or more types.

(Production of resin particles (A))
The resin particles (A) are produced by a method in which the above-mentioned optional components such as a polyester resin, a surfactant, and a colorant are mixed in an aqueous medium to obtain a resin particle (A) dispersion.

As the aqueous medium, those containing water as a main component are preferable. From the viewpoint of environmental properties and the viewpoint of improving the emulsifiability of the resin, the content of water in the aqueous medium is preferably 80% by mass or more, and 90% by mass or more. More preferably, it is more preferably 95% by mass or more, substantially more preferably 100% by mass, and still more preferably 100% by mass. As water, deionized water or distilled water is preferably used.
As components other than water, organic solvents that dissolve in water such as alkyl alcohols having 1 to 5 carbon atoms; dialkyl ketones having 1 to 3 carbon atoms such as acetone and methyl ethyl ketone; and cyclic ethers such as tetrahydrofuran are used. Among these, from the viewpoint of preventing the organic solvent from being mixed into the toner, an alkyl alcohol having 1 to 5 carbon atoms that does not dissolve the polyester resin is preferable, and methanol, ethanol, isopropanol, and butanol are more preferable.

  As a method for obtaining a dispersion containing the resin particles (A), a method of adding a resin or the like to an aqueous medium and performing a dispersion treatment with a disperser or the like, or an aqueous medium is gradually added to the resin or the like to perform phase inversion emulsification. From the viewpoint of widening the fixable temperature range of the obtained toner, a method using phase inversion emulsification is preferable. Hereinafter, a method by phase inversion emulsification will be described.

First, the above-mentioned optional components such as a polyester resin, a surfactant, and a colorant are melted and mixed to obtain a resin mixture.
When the polyester resin is composed of a plurality of resins, a mixture of polyester and other resins may be used in advance, but when other components are added, they are added simultaneously and melted and mixed. A resin mixture may be obtained.

  As a method for obtaining a resin mixture, there is a method in which the above-mentioned optional components such as polyester resin, surfactant, colorant, and alkaline aqueous solution are placed in a container, and the resin is melted and mixed uniformly while stirring with a stirrer. preferable.

  Examples of the alkali in the alkaline aqueous solution include hydroxides of alkali metals such as potassium hydroxide and sodium hydroxide, and ammonia. From the viewpoint of improving the emulsifiability of the resin, potassium hydroxide and sodium hydroxide may be used. preferable. Further, the alkali concentration in the alkaline aqueous solution is preferably 30% by mass or less, more preferably 20% by mass or less, further preferably 10% by mass or less, more preferably 1% by mass or more, and more preferably 1.5% by mass or more. More preferred is 2% by mass or more.

  The temperature at which the resin is melted and mixed is preferably equal to or higher than the glass transition temperature of the polyester resin from the viewpoint of obtaining homogeneous resin particles, and more preferably equal to or higher than the melting point when crystalline polyester is included.

  Next, an aqueous medium is added to the resin mixture and phase inversion is performed to obtain a dispersion containing resin particles (A).

  From the viewpoint of obtaining homogeneous resin particles, the temperature at which the aqueous medium is added is preferably not less than the glass transition temperature of the polyester resin, and more preferably not less than the melting point when the crystalline polyester is included.

  The addition rate of the aqueous medium is preferably 50 parts by mass or less per 100 parts by mass of the resin constituting the resin particles (A) until the phase inversion is completed from the viewpoint of making the resin particles small. , 30 parts by mass or less is more preferable, 10 parts by mass or less is more preferable, 5 parts by mass or less is more preferable, 0.1 parts by mass or more is preferable, and 0.5 parts by mass is preferable. / Min or more is more preferable. There is no restriction | limiting in the addition speed | rate of the aqueous medium after the resin phase is obtained after phase inversion.

  The amount of the aqueous medium used is preferably 900 parts by mass or less and more preferably 500 parts by mass or less with respect to 100 parts by mass of the resin constituting the resin particles (A) from the viewpoint of obtaining uniform aggregated particles in the subsequent aggregation step. Preferably, 300 parts by mass or less is more preferable, 100 parts by mass or more is preferable, 150 parts by mass or more is more preferable, and 170 parts by mass or more is further preferable.

From the viewpoint of widening the fixing temperature range of the toner and improving the chargeability, the polyester resin constituting the resin particles (A) is preferably cross-linked, and more preferably cross-linked by a compound having an oxazoline group.
The compound having an oxazoline group preferably contains a plurality of oxazoline groups in the molecule, and more preferably a polymer containing an oxazoline group. The weight average molecular weight of the polymer containing an oxazoline group is preferably 2,000,000 or less, more preferably 1,000,000 or less, and more preferably 500 or more, from the viewpoint of increasing the reactivity with the polyester resin. 1,000 or more is more preferable.
Examples of commercially available polymers containing oxazoline groups include EPOCROSS WS series (water-soluble type, main chain acrylic), K series (emulsion type, main chain styrene / acrylic) manufactured by Nippon Shokubai Co., Ltd. Name).
The content or addition amount of the compound having an oxazoline group is based on 100 parts by mass of the total amount of the resin in the dispersion of the resin particles (A) from the viewpoint of enhancing the crosslinking reactivity with the resin and improving the productivity. The solid content is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, further preferably 10 parts by mass or less, more preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and 1 part by mass. Part or more is more preferable.

  By adding and mixing a compound having an oxazoline group, the polyester resin contained in the resin particles (A) dispersed in the dispersion is cross-linked. The temperature during the crosslinking reaction is preferably 100 ° C. or lower, more preferably 98 ° C. or lower, 60 ° C. or higher, more preferably 70 ° C. or higher. The presence of the crosslinking can be confirmed by analyzing the presence of the amide group by a technique such as infrared absorption spectrum analysis.

  The solid content concentration of the obtained dispersion of resin particles (A) is preferably 50% by mass or less from the viewpoint of improving the stability of the resin particle dispersion and facilitating handling. % By mass or less is more preferable, 35% by mass or less is further preferable, 30% by mass or less is further more preferable, 10% by mass or more is preferable, 15% by mass or more is more preferable, and 20% by mass or more is still more preferable. Preferably, 25 mass% or more is still more preferable. In addition, solid content is the total amount of non-volatile components, such as resin and surfactant.

The volume median particle size (D ₅₀ ) of the resin particles (A) in the dispersion of the obtained resin particles (A) is preferably 2 μm or less from the viewpoint of obtaining a high-quality toner, The following is more preferable, 1 μm or less is further preferable, 0.5 μm or less is further preferable, 0.02 μm or more is preferable, 0.05 μm or more is more preferable, 0.08 μm or more is further preferable, and 0. 10 micrometers or more are still more preferable. Here, the volume-median particle size (D ₅₀ ) is a particle size at which the cumulative volume frequency calculated by the volume fraction is 50% when calculated from the smaller particle size. The volume median particle diameter (D ₅₀ ) of the resin particles is specifically determined by the method described in the examples.
Further, the coefficient of variation (CV value) (%) of the particle size distribution of the resin particles (A) is preferably 40% or less, more preferably 35% or less, and more preferably 30% or less from the viewpoint of obtaining a high-quality toner. Is more preferable. Moreover, 5% or more is preferable from a viewpoint of productivity. In addition, the CV value of the resin particles is a value represented by the following formula, and is specifically obtained by the method described in the examples.
CV value (%) = [standard deviation of particle size distribution (μm) / volume median particle size (μm)] × 100

[Production of Aggregated Particles (1)]
Aggregated particles (1) are produced by a method in which optional components such as resin particles (A), release agent particles, aggregating agents, and colorants are mixed in an aqueous medium to obtain aggregated particles (1). Here, when mixing the said component, it is preferable to make it aggregate and obtain as a dispersion liquid of aggregated particle (1).

In this step, it is preferable to first mix the resin particles (A) and release agent particles in an aqueous medium to obtain a mixed dispersion.
In addition, when a colorant is not mixed with the resin particles (A) in the step (1), it is preferable to mix a colorant in this step.
In this step, resin particles other than the resin particles (A) may be mixed. As resin particles other than resin particles (A), resin particles containing amorphous polyester are preferable, and those having the same composition as resin particles (B) described later are more preferable.
There is no restriction | limiting in order of mixing, You may add any in order and may add simultaneously.

In 100 parts by mass of the mixed dispersion, the resin particles (A) are preferably 40 parts by mass or less, more preferably 30 parts by mass or less, more preferably 10 parts by mass or more, and more preferably 15 parts by mass or more.
In 100 parts by mass of the mixed dispersion, the aqueous medium is preferably 85 parts by mass or less, more preferably 80 parts by mass or less, more preferably 50 parts by mass or more, and more preferably 60 parts by mass or more.
From the viewpoint of improving the releasability of the toner, from the viewpoint of widening the fixable temperature range, and from the viewpoint of improving the chargeability, the release agent particles are 15 parts by mass or less with respect to 100 parts by mass of the resin particles (A). More preferred is 2 parts by mass or more.
When the colorant is mixed in this step, the content of the colorant is adjusted to 100 parts by mass of the resin constituting the resin particles (A) from the viewpoint of improving the toner image density and improving the low-temperature fixability. On the other hand, 20 parts by mass or less is preferable, 10 parts by mass or less is more preferable, 1 part by mass or more is preferable, and 5 parts by mass or more is more preferable.
The mixing temperature is preferably 0 to 40 ° C. from the viewpoint of controlling aggregation.

Next, the particles in the mixed dispersion can be aggregated to suitably obtain a dispersion of aggregated particles (1). A flocculant is added for efficient aggregation.
As the flocculant, an inorganic flocculant such as a cationic surfactant of a quaternary salt, an organic flocculant such as polyethyleneimine, an inorganic metal salt, an inorganic ammonium salt, or a bivalent or higher metal complex is used.
Examples of the inorganic metal salt include metal salts such as sodium sulfate, sodium chloride, calcium chloride, magnesium sulfate, and calcium nitrate, and inorganic metal salt polymers such as polyaluminum chloride and polyaluminum hydroxide. Examples of inorganic ammonium salts include ammonium sulfate, ammonium chloride, and ammonium nitrate. The flocculant is preferably an inorganic ammonium salt and more preferably ammonium sulfate from the viewpoint of improving the flocculence and obtaining uniform agglomerated particles.
The amount of the flocculant used is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and more preferably 30 parts by mass with respect to 100 parts by mass of the resin constituting the resin particles (A) from the viewpoint of improving the chargeability of the toner. Part or less is more preferable. Further, from the viewpoint of improving the cohesiveness of the resin particles (A), 1 part by mass or more is preferable, 10 parts by mass or more is more preferable, and 20 parts by mass with respect to 100 parts by mass of the resin constituting the resin particles (A). The above is more preferable.

  As an aggregating method, an aggregating agent is preferably added dropwise as an aqueous solution to a container containing a mixed dispersion. The flocculant may be added at one time, or may be added intermittently or continuously. However, it is preferable to perform sufficient stirring at the time of addition and after completion of the addition. From the viewpoint of controlling aggregation and shortening the toner production time, the dropping time of the aggregating agent is preferably 1 to 120 minutes. The dropping temperature is preferably 0 to 50 ° C. from the viewpoint of controlling aggregation.

At the time of agglomeration, from the viewpoint of controlling the particle size of the agglomerated particles and suppressing the formation of coarse particles, the temperature in the agglomerated system is 25 ° C. or lower than the glass transition temperature of the resin constituting the resin particles (A). The temperature is preferably 25 ° C. or more and 15 ° C. or more higher than the glass transition temperature, more preferably 35 ° C. or more and 10 ° C. or less higher than the glass transition temperature. It is preferable to confirm the progress of aggregation by monitoring the volume-median particle size (D ₅₀ ) of the aggregated particles in the temperature range. The volume median particle size (D ₅₀ ) is measured by the method described in the examples.

The volume-median particle size (D ₅₀ ) of the obtained aggregated particles (1) is preferably 10 μm or less, more preferably 8 μm or less, and more preferably 6 μm from the viewpoint of reducing the toner particle size and suppressing toner scattering. The following is more preferable, 1 μm or more is preferable, 2 μm or more is more preferable, and 3 μm or more is further preferable. Further, the CV value is preferably 30% or less, more preferably 28% or less, and further preferably 25% or less. Moreover, 5% or more is preferable from a viewpoint of productivity. The volume median particle size (D ₅₀ ) and CV value of the aggregated particles (1) are specifically determined by the method described in the examples.

<Step (3)>
Step (3) is a step of obtaining the aggregated particles (2) by adding the resin particles (B) to the aqueous medium containing the aggregated particles (1).
In this step, the dispersion of resin particles (B) is added to the dispersion of aggregated particles (1) obtained in step (2), and the resin particles (B) are further adhered to the aggregated particles (1). It is preferable to obtain aggregated particles (2).

[Resin particles (B)]
In the present invention, the resin particles (B) preferably contain a polyester resin from the viewpoint of improving the low-temperature fixability of the toner, widening the fixable temperature range, and improving the chargeability.

The resin particles (B) preferably contain 80% by mass or more of the polyester resin with respect to the resin in the resin particles (B) from the viewpoint of improving the low-temperature fixability of the toner and widening the fixable temperature range. 90 mass% or more is more preferable, 95 mass% or more is still more preferable, it is still more preferable to contain substantially 100 mass%, and it is still more preferable to contain 100 mass%.
As the polyester resin that can be contained in the resin particles (B), the same polyester resin as that that can be contained in the resin particles (A) can be suitably used. A resin having the same composition as that of the polyester resin that can be contained in the resin particles (A) may be used, or a resin having a different composition may be used, but the viewpoint of improving the low-temperature fixability of the toner and the fixable temperature range are widened. From the viewpoint, it is preferable to use resins having the same composition.
The resin particles (B) may further contain a known resin usually used for toner, for example, a resin such as a styrene-acrylic copolymer, an epoxy resin, a polycarbonate, and a polyurethane, together with the polyester resin.

Similarly to the resin particles (A) described above, the resin particles (B) may contain a colorant, a release agent, and a charge control agent as long as the effects of the present invention are not impaired. Moreover, you may contain additives, such as reinforcement fillers, such as a fibrous material, antioxidant, and anti-aging agent, as needed.
The resin particles (B) are preferably obtained as a dispersion of the resin particles (B) by the same method as the method for producing the resin particles (A) described above. The alkaline aqueous solution, surfactant, and aqueous medium used are also resins. The thing similar to the manufacturing method of particle | grains (A) can be used suitably. Resin particles (A) can also be used as resin particles (B).

The volume median particle size (D ₅₀ ) of the resin particles (B) in the dispersion of the resin particles (B) is preferably 2 μm or less, more preferably 1.5 μm or less from the viewpoint of obtaining a high-quality toner. Preferably, 1 μm or less is further preferable, 0.5 μm or less is more preferable, 0.02 μm or more is preferable, 0.05 μm or more is more preferable, 0.08 μm or more is further preferable, and 0.10 μm or more is preferable. Even more preferred.
In addition, the coefficient of variation (CV value) (%) of the particle size distribution of the resin particles (B) is preferably 40% or less, more preferably 35% or less, and more preferably 30% or less from the viewpoint of obtaining a high-quality toner. Is more preferable. Moreover, 5% or more is preferable from a viewpoint of productivity. The volume median particle size and CV value of the resin particles (B) are determined by the same method as that for the resin particles (A), and specifically by the method described in the examples.

  The solid content concentration of the dispersion of the resin particles (B) is preferably 50% by mass or less and 40% by mass or less from the viewpoint of improving the stability of the obtained resin particle dispersion and facilitating handling. More preferably, 30% by mass or less is further preferable, 10% by mass or more is preferable, 15% by mass or more is more preferable, and 20% by mass or more is further preferable.

[Production of Aggregated Particles (2)]
Aggregated particles (2) are produced by adding resin particles (B) to an aqueous medium containing aggregated particles (1).
Further, the aggregated particles (2) are obtained by adding a dispersion of resin particles (B) to the dispersion of aggregated particles (1) obtained in step (2), and further adding resin particles (B) to the aggregated particles (1). It is preferable to produce a dispersion of aggregated particles (2).

Before adding the dispersion containing resin particles (B) (dispersion of resin particles (B)) to the dispersion containing aggregated particles (1) (dispersion of aggregated particles (1)), the aggregated particles ( It is preferable to dilute the dispersion of 1) by adding an aqueous medium. By adding the aqueous medium, the resin particles (B) can be more uniformly attached to the aggregated particles (1).
When the dispersion liquid of the resin particles (B) is added to the dispersion liquid of the aggregated particles (1), the aggregating agent may be used for efficiently attaching the resin particles (B) to the aggregated particles (1). .
As a preferable addition method in the case of adding the dispersion liquid of the resin particles (B) to the dispersion liquid of the aggregated particles (1), a method of simultaneously adding the aggregation liquid and the dispersion liquid of the resin particles (B), the aggregating agent and the resin Examples thereof include a method of alternately adding a dispersion of particles (B) and a method of adding a dispersion of resin particles (B) while gradually increasing the temperature of the dispersion of aggregated particles (1). By doing in this way, the cohesiveness fall of the aggregated particle (1) and the resin particle (B) by the coagulant | flocculant density | concentration fall can be prevented. From the viewpoint of improving the productivity of the toner and simplifying the production, it is preferable to add the dispersion of the resin particles (B) while gradually increasing the temperature of the dispersion of the aggregated particles (1).

  The temperature in the system in this step is higher than the melting point when the polyester constituting the resin particles (A) contains crystalline polyester from the viewpoint of widening the fixable temperature range of the toner and improving the chargeability. The temperature is preferably 5 ° C. or higher and 3 ° C. or lower than the glass transition temperature of the resin constituting the resin particles (B). When the aggregated particles (2) are produced in the temperature range, the fixing temperature range and chargeability of the obtained toner are improved. Although the reason is not certain, it is considered that the generation of coarse particles is suppressed because fusion of the aggregated particles (2) does not occur.

  The addition amount of the resin particles (B) is from the viewpoint of widening the fixable temperature range of the toner, the viewpoint of improving the charging property, and the viewpoint of improving the hot offset resistance, and the resin particles (B) and the resin particles (A). The mass ratio (resin particles (B) / resin particles (A)) is preferably 1.5 or less, more preferably 1.0 or less, still more preferably 0.5 or less, and preferably 0.10 or more. 0.20 or more is more preferable, and 0.25 or more is more preferable.

  The resin particle (B) dispersion may be added continuously over a certain period of time, may be added at a time, or may be added in a plurality of divided portions. It is preferable to add them continuously or in several divided portions. By adding as described above, the resin particles (B) are likely to selectively adhere to the aggregated particles (1). Among these, it is preferable to add continuously over a certain time from the viewpoint of promoting selective adhesion and the efficiency of production. The time for continuous addition is preferably 1 to 10 hours, more preferably 2.5 to 8 hours, from the viewpoint of obtaining uniform aggregated particles (2) and from the viewpoint of shortening the production time.

The total amount of the resin particles (B) is added, and aggregation is stopped when the toner particles have grown to an appropriate particle size.
Particle size to stop the aggregation, ie The particle size of the aggregated particles (2), the volume-median particle size (D _50), from the viewpoint of obtaining a toner of high quality, preferably 10μm or less, more preferably 8μm or less, 7 μm or less is further preferable, 6 μm or less is more preferable, 1 μm or more is preferable, 2 μm or more is more preferable, 3 μm or more is further preferable, and 4 μm or more is even more preferable.
Methods for stopping the aggregation include a method of cooling the dispersion and a method of adding an aggregation terminator. From the viewpoint of reliably preventing unnecessary aggregation, the aggregation is stopped by adding an aggregation terminator. The method of making it preferable is.
As the aggregation terminator, a surfactant is preferable, and an anionic surfactant is more preferable. Anionic surfactants include alkyl ether sulfates, alkyl sulfates, polyoxyethylene alkyl ether sulfates, and linear alkyl benzene sulfonates. The aggregation terminators can be used alone or in combination of two or more.
From the viewpoint of stopping aggregation, the addition amount of the aggregation terminator is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, and more preferably 3 parts by mass or more with respect to 100 parts by mass of the total amount of the resin in the system. Further preferred. Further, from the viewpoint of reducing the residual amount in the toner, it is preferably 15 parts by mass or less, more preferably 10 parts by mass or less, and still more preferably 8 parts by mass or less with respect to 100 parts by mass of the total amount of resin in the system. The aggregation terminator may be added in any form, but is preferably added as an aqueous solution from the viewpoint of improving productivity.

<Process (4)>
Step (4) is a step in which fused particles (2) obtained in step (3) are fused to obtain fused particles. In the aggregated particles (2), the particles that are mainly physically attached to each other are fused and integrated to form fused particles.

  From the viewpoint of improving the fusibility of the agglomerated particles and the viewpoint of improving the productivity of the toner, in this step, a temperature that is preferably 10 ° C. lower than the glass transition temperature of the resin constituting the agglomerated particles (2), More preferably, it is maintained at a temperature not lower than the glass transition temperature, more preferably not lower than 5 ° C. higher than the glass transition temperature. In addition, from the viewpoint of widening the fixable temperature range of the toner and improving the chargeability, in this step, a temperature not higher than the glass transition temperature of the resin constituting the aggregated particles (2) is preferably 30 ° C. or lower. More preferably, the temperature is kept at a temperature not higher than 25 ° C.

  The holding time in this step is 0.5 to 24 from the viewpoint of improving the fusing property of the aggregated particles, the viewpoint of widening the fixable temperature range of the toner, the viewpoint of improving the charging property, and the viewpoint of improving the productivity. Time is preferable, 0.75 to 12 hours is more preferable, and 1 to 8 hours is still more preferable.

The volume median particle size (D ₅₀ ) of the fused particles obtained in this step is preferably 2 to 10 μm, more preferably 2 to 8 μm, still more preferably 2 to 7 μm, from the viewpoint of obtaining a high quality toner. -7 μm is still more preferable, and 4-6 μm is even more preferable.

[Post-processing process]
In the present invention, a post-treatment step may be performed after step (4), and it is preferable to obtain toner particles by isolating the fused particles.
Since the fused particles obtained in the step (4) are present in the aqueous medium, it is preferable to first perform solid-liquid separation. For solid-liquid separation, a suction filtration method or the like is preferably used.
It is preferable to perform washing after the solid-liquid separation. When a nonionic surfactant is used in the production of the resin particles (A) and (B), it is preferable to remove the added nonionic surfactant, so the cloud point of the nonionic surfactant In the following, it is preferable to wash with an aqueous medium. The washing is preferably performed a plurality of times.
Next, although it is preferable to dry, the temperature at the time of drying is lower than the glass transition temperature of the resin constituting the fused particles by 5 ° C. or more, and includes crystalline polyester. The temperature is preferably set to be 5 ° C. or more lower than the melting point, and more preferably set to be 10 ° C. or more lower. As a drying method, it is preferable to use a vacuum low temperature drying method, a vibration type fluidized drying method, a spray drying method, a freeze drying method, a flash jet method, or the like.

The volume-median particle size (D ₅₀ ) of the obtained toner particles is preferably 10 μm or less, more preferably 8 μm or less, still more preferably 7 μm or less, and further preferably 6 μm from the viewpoint of improving the image quality of the toner and improving productivity. The following is more preferable, 1 μm or more is preferable, 2 μm or more is more preferable, 3 μm or more is further preferable, and 4 μm or more is even more preferable.

The CV value of the toner particles is preferably 30% or less, more preferably 28% or less, and even more preferably 27% or less, from the viewpoints of improving image quality and improving productivity. Moreover, 5% or more is preferable from a viewpoint of productivity.
The volume median particle size (D ₅₀ ) and CV value of the toner particles are determined by the method described in the examples.

  The circularity of the toner particles is preferably 0.985 or less, more preferably 0.980 or less, and more preferably 0.955, from the viewpoint of suppressing scattering of toner in a printing machine such as a printer and improving cleaning properties. The above is preferable, 0.965 or more is more preferable, and 0.970 or more is more preferable. The circularity of the toner particles can be measured by the method described in the examples. The circularity of the toner particles is a value obtained by the ratio of the circumference of a circle equal to the projected area to the circumference of the projected image (ratio of the circumference of the circle equal to the projected area / the circumference of the projected image). The more spherical the particles are, the closer the circularity is to 1.

<Toner for electrophotography>
(toner)
The toner particles obtained by drying or the like can be used as they are as the toner of the present invention, but it is preferable to use toner particles whose surface has been treated as described below as the toner for electrophotography.
The softening point of the obtained 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 widening the fixable temperature range and improving the chargeability. The glass transition temperature is preferably from 30 to 80 ° C., more preferably from 40 to 70 ° C., from the viewpoint of widening the fixable temperature range and improving the chargeability.

(External additive)
In the electrophotographic toner of the present invention, the toner particles can be used as the toner as they are, but it is preferable to use a toner obtained by adding a fluidizing agent or the like to the toner particle surface as an external additive.
Examples of the external additive include inorganic fine particles such as hydrophobic silica, titanium oxide fine particles, alumina fine particles, cerium oxide fine particles, and carbon black, and polymer fine particles such as polycarbonate, polymethyl methacrylate, and silicone resin. Of these, hydrophobic silica is preferred.
When the surface treatment of the toner particles is performed using the external additive, the amount of the external additive added is preferably 1 to 5 parts by mass with respect to 100 parts by mass of the toner particles before the treatment with the external additive. A mass part is more preferable and 2.5-4.5 mass part is still more preferable.

  The toner for electrophotography obtained by the present invention can be used as a one-component developer or as a two-component developer by mixing with a carrier.

In the present specification, the following method for producing an electrophotographic toner and an electrophotographic toner are disclosed.
<1> A method for producing an electrophotographic toner comprising the following steps (1) to (4).
Step (1): Step of preparing release agent particles containing wax and inorganic fine particles Step (2): Release agent particles obtained in Step (1), resin particles (A), and aggregating agent, Step of obtaining aggregated particles (1) by mixing in an aqueous medium Step (3): Step of adding resin particles (B) to an aqueous medium containing aggregated particles (1) to obtain aggregated particles (2) 4): Step of fusing the agglomerated particles (2) to obtain fused particles

<2> The method for producing an electrophotographic toner according to <1>, wherein the wax includes paraffin wax.
<3> The melting point of the wax is preferably 100 ° C. or lower, more preferably 90 ° C. or lower, still more preferably 85 ° C. or lower, still more preferably 80 ° C. or lower, and preferably 50 ° C. or higher, more preferably The method for producing an electrophotographic toner according to <1> or <2>, which is 60 ° C. or higher, more preferably 65 ° C. or higher, and still more preferably 70 ° C. or higher.
<4> The amount of the wax added is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and still more preferably 10 to 100 parts by mass in total of the resin of the resin particles (A) and resin particles (B). The toner for electrophotography according to any one of <1> to <3>, which is 1 part by mass or less, preferably 1 part by mass or more, more preferably 3 parts by mass or more, and still more preferably 5 parts by mass or more. Manufacturing method.

<5> The inorganic fine particles are at least one selected from silica, titanium oxide and aluminum oxide, more preferably at least one selected from silica and titanium oxide, and more preferably silica, <1> to <4 The method for producing an electrophotographic toner according to any one of the above.
<6> The method for producing an electrophotographic toner according to any one of <1> to <5>, wherein the surface of the inorganic fine particles is subjected to a hydrophobic treatment.
<7> In any one of <1> to <6>, wherein the inorganic fine particle is silica hydrophobized with at least one treatment agent selected from silicone oil, dimethyldichlorosilane, and hexamethyldisilazane. A method for producing the electrophotographic toner according to claim.
<8> The average primary particle size of the inorganic fine particles is 5 nm or more and 90 nm or less, more preferably 50 nm or less, still more preferably 30 nm or less, still more preferably 20 nm or less, and preferably 5 nm or more, more preferably Is 8 nm or more, more preferably 12 nm or more, The method for producing an electrophotographic toner according to any one of <1> to <7>.
<9> The specific gravity of the inorganic fine particles is 1.3 or more and 5 or less, more preferably 4.5 or less, further preferably 3.5 or less, still more preferably 3.0 or less, and more preferably. Is 1.5 or more, more preferably 2.0 or more, The method for producing an electrophotographic toner according to any one of <1> to <8>.
<10> The mass ratio of the wax to the inorganic fine particles (the mass of the wax / the mass of the inorganic fine particles) is 95/5 to 50/50, more preferably 95/5 to 60/40, and still more preferably 90/10 to 70/30. The method for producing an electrophotographic toner according to any one of <1> to <9>, more preferably 85/15 to 75/25.

<11> The toner for electrophotography according to any one of <1> to <10>, wherein step (1) is a step of preparing release agent particles by dispersing wax and inorganic fine particles in an aqueous medium. Manufacturing method.
<12> The electrophotographic image according to <11>, wherein the step (1) comprises dispersing the wax and inorganic fine particles in an aqueous medium in an aqueous medium at a temperature not lower than the melting point of the wax in the presence of a surfactant. Toner manufacturing method.
<13> The method for producing a toner for electrophotography according to <12>, wherein the surfactant is an anionic surfactant, preferably dipotassium alkenyl succinate.
<14> The content of the surfactant is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, still more preferably 10 parts by mass or less, with respect to 100 parts by mass of the total amount of wax and inorganic fine particles. More preferably, it is 5 parts by mass or less, preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, further preferably 1 part by mass or more, and still more preferably 1.5 parts by mass or more. The method for producing an electrophotographic toner according to <12> or <13>.

<15> The volume median particle size (D ₅₀ ) of the release agent particles is 0.10 μm or more and 1 μm or less, more preferably 0.70 μm or less, still more preferably 0.60 μm or less, and still more preferably 0. 0.55 μm or less, more preferably 0.30 μm or more, still more preferably 0.40 μm or more, still more preferably 0.45 μm or more, and even more preferably 0.48 μm or more. <1> to <14 The method for producing an electrophotographic toner according to any one of the above.
<16> The CV value of the release agent particles is preferably 60% or less, more preferably 55% or less, preferably 20% or more, more preferably 30% or more, still more preferably 40% or more, The method for producing an electrophotographic toner according to any one of <1> to <15>, further preferably 45% or more.

<17> The resin of the resin particles (A) and (B) is a polyester resin that is 80% by mass or more, more preferably 90% by mass or more, and still more preferably 95% by mass with respect to the resin in each particle. As described above, the method for producing an electrophotographic toner according to any one of <1> to <16>, further preferably 100% by mass, and still more preferably 100% by mass.
<18> The content of the amorphous polyester in the polyester resin in the resin particles (A) is preferably 80 to 100% by mass, more preferably 90 to 100% by mass, and still more preferably 95 to 100% by mass. The method for producing an electrophotographic toner according to <17>, further preferably substantially 100% by mass, and still more preferably 100% by mass.
<19> The method for producing an electrophotographic toner according to any one of <1> to <18>, wherein the resin particles (A) contain a colorant.
<20> The volume median particle size (D ₅₀ ) of the resin particles (A) is preferably 2 μm or less, more preferably 1.5 μm or less, still more preferably 1 μm or less, and even more preferably 0.5 μm or less, The electron according to any one of <1> to <19>, which is preferably 0.02 μm or more, more preferably 0.05 μm or more, still more preferably 0.08 μm or more, and still more preferably 0.10 μm or more. A method for producing a photographic toner.
<21> The volume-median particle size (D ₅₀ ) of the aggregated particles (1) is preferably 10 μm or less, more preferably 8 μm or less, still more preferably 6 μm or less, and preferably 1 μm or more, more preferably 2 μm. As mentioned above, The manufacturing method of the toner for electrophotography in any one of <1>-<20> which is 3 micrometers or more more preferably.
<22> The volume median particle size (D ₅₀ ) of the resin particles (B) is preferably 2 μm or less, more preferably 1.5 μm or less, still more preferably 1 μm or less, and even more preferably 0.5 μm or less, Moreover, the electron according to any one of <1> to <21>, which is preferably 0.02 μm or more, more preferably 0.05 μm or more, further preferably 0.08 μm or more, and still more preferably 0.10 μm or more. A method for producing a photographic toner.
<23> The volume median particle size (D ₅₀ ) of the agglomerated particles (2) is preferably 10 μm or less, more preferably 8 μm or less, still more preferably 7 μm or less, still more preferably 6 μm or less, and preferably The method for producing an electrophotographic toner according to any one of <1> to <22>, which is 1 μm or more, more preferably 2 μm or more, still more preferably 3 μm or more, and still more preferably 4 μm or more.

<24> An electrophotographic toner obtained by the production method according to any one of <1> to <23>.
<25> A method for producing a release agent particle dispersion for an electrophotographic toner, wherein wax and inorganic fine particles are dispersed in an aqueous medium to prepare release agent particles.
<26> A method for preventing the release agent particles from being liberated in the production of an electrophotographic toner, wherein inorganic fine particles are added to the release agent particles containing wax.

  Each property value of polyester, resin particles, toner, etc. was measured and evaluated by the following method.

[Polyester softening point, endothermic peak temperature, crystallinity index, glass transition temperature]
(1) Softening point Using a flow tester “CFT-500D” (manufactured by Shimadzu Corporation), a 1 g sample was heated at a heating rate of 6 ° C./min, and a load of 1.96 MPa was applied by a plunger, and the diameter was 1 mm. And extruded from a 1 mm long nozzle. The amount of plunger drop of the flow tester was plotted against the temperature, and the temperature at which half of the sample flowed out was taken as the softening point.
(2) Maximum endothermic peak temperature and crystallinity index Using a differential scanning calorimeter “Q100” (manufactured by TA Instruments Japan Co., Ltd.), it is 0 at a temperature drop rate of 10 ° C./min from room temperature (20 ° C.). The sample cooled to 0 ° C. was allowed to stand still for 1 minute, and then heated to 180 ° C. at a temperature rising rate of 10 ° C./min. Of the observed peaks, the peak temperature with the maximum peak area is defined as the endothermic maximum peak temperature (1), and the crystallinity by (softening point (° C)) / (maximum endothermic peak temperature (1) (° C)). The index was determined.
(3) Glass transition temperature The temperature was raised to 200 ° C. using a differential scanning calorimeter “Q100” (manufactured by TA Instruments Japan Co., Ltd.), and the temperature was cooled to 0 ° C. at a cooling rate of 10 ° C./min. The measured samples were measured at a heating rate of 10 ° C./min. When an endothermic peak is observed, the temperature of the peak is measured. When a step is observed without the peak being observed, a tangent indicating the maximum slope of the curve of the step and an extension of the baseline on the high temperature side of the step The temperature at the point of intersection was taken as the glass transition temperature.

[Acid value of polyester]
It measured according to JIS K0070. However, the measurement solvent was a mixed solvent of acetone and toluene (acetone: toluene = 1: 1 (volume ratio)).

[Melting point of wax]
A differential scanning calorimeter “Q100” (manufactured by TA Instruments Japan Co., Ltd.) was used to measure from 20 ° C. at a heating rate of 10 ° C./min, and the maximum peak temperature was taken as the melting point.

[Average primary particle size of inorganic fine particles]
The particle size (average value of major axis and minor axis) of 500 particles was measured from a scanning electron microscope (SEM) photograph, and the average value was defined as the average primary particle size.

[Specific gravity of inorganic fine particles and polyester]
The specific gravity of the sample was determined using “MULTIVOLUME PYCNOMETER 1305” (manufactured by Shimadzu Corporation). The measurement temperature was 25 ° C., a 10 cm ³ container was used, and as a pretreatment of the sample, helium gas purge was performed 3 times at 19.3 to 19.7 psi · G (1 psi = 6.889476 × 10 ⁵ Pa). The measurement was performed three times, and the average value was taken as the specific gravity.

[Volume Median Particle Size (D ₅₀ ) and CV Value of Resin Particles, Release Agent Particles]
(1) Measuring apparatus: Laser diffraction particle size measuring instrument “LA-920” (manufactured by Horiba, Ltd.)
(2) Measurement conditions: Distilled water was added to the measurement cell, and the volume-median particle size (D ₅₀ ) was measured at a temperature at which the absorbance falls within an appropriate range. The CV value was calculated according to the following formula.
CV value (%) = (standard deviation of particle size distribution / volume median particle size (D ₅₀ )) × 100

[Solid content concentration of resin particle dispersion and release agent particle dispersion]
Using an infrared moisture meter “FD-230” (manufactured by Kett Science Laboratory Co., Ltd.), a measurement sample 5 g was dried at a temperature of 150 ° C. and in a measurement mode 96 (monitoring time 2.5 minutes / variation width 0.05%). The moisture percentage was measured. The solid content concentration was calculated according to the following formula.
Solid content concentration (% by mass) = 100-M
M: moisture (%) = [(W−W ₀ ) / W] × 100
W: Sample mass before measurement (initial sample mass)
W ₀ : Mass of sample after measurement (absolute dry mass)

[Volume Median Particle Size (D ₅₀ ) and CV Value of Toner Particles and Aggregated Particles]
The volume median particle size of the toner particles was measured as follows.
-Measuring machine: Coulter Multisizer III (trade name, manufactured by Beckman Coulter)
・ Aperture diameter: 50μm
-Analysis software: Multisizer III version 3.51 (trade name, manufactured by Beckman Coulter)
・ Electrolyte: Isoton II (trade name, manufactured by Beckman Coulter)
Dispersion: Polyoxyethylene lauryl ether “Emulgen 109P” (manufactured by Kao Corporation, HLB: 13.6) was dissolved in the electrolytic solution to obtain a dispersion having a concentration of 5% by mass.
-Dispersion condition: 10 mg of a toner measurement sample is added to 5 mL of the dispersion, and dispersed for 1 minute with an ultrasonic disperser, and then 25 mL of electrolyte is added, and further dispersed for 1 minute with an ultrasonic disperser. A sample dispersion was 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. From this, the volume median particle size (D ₅₀ ) was determined.
The CV value (%) was calculated according to the following formula.
CV value (%) = (standard deviation of particle size distribution / volume median particle size (D ₅₀ )) × 100
The volume median particle size of the aggregated particles (1) and the aggregated particles (2) includes the aggregated particles (1) and the aggregated particles (2) as sample dispersions in the measurement of the volume median particle size of the toner particles. The same measurement was performed using the dispersion.

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

[Evaluation of toner fixing properties]
Using a commercially available printer “Microline 5400” (Oki Data Co., Ltd.) on high quality paper “J paper A4 size” (Fuji Xerox Co., Ltd.), the toner adhesion amount on the paper is 0.42 to 0.48 mg / cm ^2. The solid image was output without fixing at a length of 50 mm, leaving a margin of 5 mm from the top edge of the A4 paper.
Next, the same printer with the temperature-variable fixing device prepared was prepared, the temperature of the fixing device was set to 90 ° C., and fixing was performed at a speed of 1.5 seconds per sheet in the A4 longitudinal direction, thereby obtaining a printed matter.
In the same manner, the temperature of the fixing device was increased by 5 ° C., and the fixing was performed to obtain a printed matter.
A 500 g weight is applied to the solid image from the top margin of the printed image and a solid image with a 50 mm long mending tape “Scotch Mending Tape 810” (18 mm wide by 3M). And reciprocally pressed at a speed of 10 mm / sec. Thereafter, the affixed tape was peeled off from the lower end side at a peeling angle of 180 degrees and a speed of 10 mm / sec to obtain a printed matter after the tape was peeled off. 30 high-quality paper “Excellent White Paper A4 Size” (manufactured by Oki Data Co., Ltd.) is laid under the printed matter before and after the tape is applied, and the reflected image density of the fixed image portion before and after the tape is applied to each printed matter. Measurement was performed using a colorimeter “SpectroEye” (manufactured by GretagMacbeth, Inc., light emission condition: standard light source D ₅₀ , observation visual field 2 °, density reference DINNB, absolute white reference), and the fixing ratio was calculated from the following formula.
Fixing rate (%) = (Reflected image density after peeling tape / Reflected image density before applying tape) × 100
The test was performed by increasing the temperature of the fixing device by 5 ° C., and the test was performed up to the temperature at which the cold offset occurs or the temperature at which the fixing rate is less than 90%, to the temperature at which the hot offset occurs. The cold offset refers to a phenomenon in which the toner on the unfixed image is not sufficiently melted and the toner adheres to the fixing roller when the temperature of the fixing device is low. The hot offset is the temperature of the fixing device. A phenomenon in which toner adheres to the fixing roller when the temperature is high. The occurrence of cold offset or hot offset can be judged again by whether the toner adheres to the paper when the fixing roller makes one or more rounds. In this test, the solid image on the paper surface is peeled off. In this case, it was determined that the offset was cold offset, and it was determined that the hot offset occurred when the toner adhered to the fixing roller adhered to the paper surface in a portion 87 mm from the upper end of the solid image on the paper surface.
Fix the temperature range from the lowest fixing temperature to the temperature 5 ° C lower than the temperature at which the hot offset occurs, with the lowest temperature out of the temperatures where the cold offset does not occur or the fixing rate is 90% or more. The temperature range (hereinafter also referred to as “fixing width”) was used. The wider the fixable temperature range, the better the toner is.

[Evaluation of toner chargeability]
At 25 ° C. and 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) are placed in a 50 cc cylindrical polypropylene bottle (Nikko Corporation). Pre-stirring was performed by shaking 10 times vertically and horizontally. Thereafter, the charge amount at a mixing time of 1 hour was measured using a tumbler mixer (manufactured by Shinmaru Enterprises) using a q / m meter (manufactured by EPPING) to obtain the charge amount. The higher the absolute value of the charge amount, the more excellent the chargeability of the toner.
Measurement equipment, settings, etc. are as follows.
Measuring instrument: q / m-meter manufactured by EPPING
Configuration:
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)

[Production of polyester]
Production Example 1
(Production of polyester X1)
The inside of a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple was replaced with nitrogen, and 3528 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, Put 1404 g of polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, 1248 g of terephthalic acid, 1541 g of dodecenyl succinic anhydride, and 40 g of di (2-ethylhexanoic acid) tin under a nitrogen atmosphere. While stirring, the temperature was raised to 230 ° C. and maintained for 6 hours, and then the pressure in the flask was further lowered and maintained at 8.3 kPa for 1 hour. Then, after cooling to 215 ° C. and returning to atmospheric pressure, 300 g of trimellitic anhydride was added and maintained at 215 ° C. for 1 hour, then the pressure in the flask was further lowered and maintained at 8.3 kPa for 3 hours. Thus, polyester X1 was obtained. The physical property values of the obtained polyester X1 are shown in Table 1.

Production Example 2
(Production of polyester X2)
The inside of a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple was replaced with nitrogen, and 3322 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, Polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane (31 g), terephthalic acid (662 g), and di (2-ethylhexanoic acid) tin (25 g) were added, and the mixture was stirred while being stirred in a nitrogen atmosphere. After raising the temperature to 0 ° C. and maintaining for 5 hours, the pressure in the flask was further lowered and maintained at 8.0 kPa for 1 hour. After returning to atmospheric pressure, the mixture was cooled to 190 ° C., 685 g of fumaric acid and 2.4 g of tert-butylcatechol (polymerization inhibitor) were added, and maintained at a temperature of 190 ° C. for 1 hour, followed by 210 ° C. over 2 hours. The temperature was raised to. Further, the pressure in the flask was lowered and maintained at 8.0 kPa for 4 hours to obtain polyester X2. The physical property values of the obtained polyester X2 are shown in Table 1.

Production Example 3
(Production of polyester X3)
The inside of a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple was replaced with nitrogen, and 3802 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 1197 g of fumaric acid and 2.5 g of tert-butylcatechol were added, heated to 180 ° C. with stirring in a nitrogen atmosphere, maintained for 1 hour, and then heated to 210 ° C. over 4 hours. Further, the pressure in the flask was lowered and maintained at 27.0 kPa for 1 hour to obtain polyester X3. The physical property values of the obtained polyester X3 are shown in Table 1.

[Production of resin particle dispersion]
Production Example 4
(Preparation of dispersion of resin particles Y1)
In a flask equipped with a stirrer, 390 g (65 parts by mass) of amorphous polyester X1, 210 g (35 parts by mass) of amorphous polyester X2, 45 g of copper phthalocyanine pigment “ECB301” (manufactured by Dainichi Seika Kogyo Co., Ltd.), polyoxy Ethylene oleyl ether “Emulgen 430” (nonionic surfactant, manufactured by Kao Corporation) 6.0 g, 15 mass% sodium dodecylbenzenesulfonate aqueous solution “Neopelex G-15” (anionic surfactant, manufactured by Kao Corporation) 40 g, 265 g of a 5 mass% potassium hydroxide aqueous solution were added, and the mixture was heated to 98 ° C. with stirring and melted, and mixed at 98 ° C. for 2 hours to obtain a resin mixture.
Next, while stirring, the temperature of the resin mixture was maintained at 98 ° C., and 1050 g of deionized water was added dropwise at a rate of 6 g / min to obtain an emulsion. The obtained emulsion was cooled to 25 ° C., and stirred at 25 ° C., 28 g of an oxazoline group-containing polymer aqueous solution “Epocross WS-700” (manufactured by Nippon Shokubai Co., Ltd., nonvolatile content 25% by mass, acrylic main chain) was added. Thereafter, the temperature was raised to 95 ° C. and held at 95 ° C. for 1 hour. Next, it was cooled to 25 ° C., and the obtained emulsion was passed through a 200 mesh (mesh opening 105 μm) wire mesh. Thereafter, deionized water was added so that the solid content concentration of the resin particle dispersion was 28% by mass to obtain a dispersion of resin particles Y1. The volume median particle size (D ₅₀ ) of the resin particles Y1 in the dispersion was 0.15 μm, and the CV value was 25%.

Production Example 5
(Preparation of dispersion of resin particles Y2)
In a flask equipped with a stirrer, 390 g of amorphous polyester X1 (65 parts by mass), 210 g of amorphous polyester X2 (35 parts by mass), polyoxyethylene oleyl ether “Emulgen 430” (nonionic surfactant, Kao) 6.0 g, 15 mass% sodium dodecylbenzenesulfonate aqueous solution “Neopelex G-15” (anionic surfactant, manufactured by Kao) 80 g, 225 g of 6 mass% potassium hydroxide aqueous solution are added and stirred. The mixture was heated to 98 ° C. and melted, and mixed at 98 ° C. for 2 hours to obtain a resin mixture.
Next, while stirring, the temperature of the resin mixture was maintained at 98 ° C., and 1050 g of deionized water was added dropwise at a rate of 6 g / min to obtain an emulsion. The obtained emulsion was cooled to 25 ° C. and passed through a 200 mesh (mesh opening 105 μm) wire mesh. Thereafter, deionized water was added so that the solid content concentration of the resin particle dispersion was 24% by mass to obtain a dispersion of resin particles Y2. The volume median particle size (D ₅₀ ) of the resin particles Y2 in the dispersion was 0.13 μm, and the CV value was 24%.

[Production of Release Agent Particle Dispersion: Step (1)]
Production Example 6
(Manufacture of dispersion liquid of release agent particles A)
In a beaker with an internal volume of 1 L, 213 g of deionized water and 5.36 g of an aqueous solution of dipotassium alkenyl succinate “Latemul ASK” (manufactured by Kao Corporation, effective concentration 28% by mass) are dissolved, and then paraffin wax “HNP-9” is dissolved therein. 40 g (manufactured by Nippon Seiki Co., Ltd., melting point 75 ° C.) and 10 g of silica fine particles “AEROSIL R972” (manufactured by Nippon Aerosil Co., Ltd., specific gravity: 2.2, average primary particle size: 16 nm, hydrophobizing agent: dimethyldichlorosilane) The mixture was stirred with a homomixer while maintaining the temperature at 95 to 98 ° C. to obtain a preliminary dispersion.
The obtained preliminary dispersion was further treated twice at a pressure of 20 MPa using a high-pressure wet atomizer “Nanomizer NM2-L200-D08” (manufactured by Yoshida Kikai Kogyo Co., Ltd.) while maintaining the temperature at 90 to 95 ° C. After cooling to room temperature, deionized water was added to adjust the solid content concentration to 20% by mass to obtain a dispersion of release agent particles A. The volume median particle size (D ₅₀ ) of the release agent particles A in the dispersion was 0.51 μm, and the CV value was 47%.

Production Example 7
(Manufacture of dispersion liquid of release agent particles B)
In a beaker with an internal volume of 1 L, 213 g of deionized water and 5.36 g of an aqueous solution of dipotassium alkenyl succinate “Latemul ASK” (manufactured by Kao Corporation, effective concentration 28% by mass) are dissolved, and then paraffin wax “HNP-9” is dissolved therein. 45 g (manufactured by Nippon Seiki Co., Ltd., melting point 75 ° C.) and 5 g of silica fine particles “AEROSIL R972” (manufactured by Nippon Aerosil Co., Ltd., specific gravity: 2.2, average primary particle size: 16 nm, hydrophobizing agent: dimethyldichlorosilane) The mixture was stirred with a homomixer while maintaining the temperature at 95 to 98 ° C. to obtain a preliminary dispersion.
The obtained preliminary dispersion was further treated twice at a pressure of 20 MPa using a high-pressure wet atomizer “Nanomizer NM2-L200-D08” (manufactured by Yoshida Kikai Kogyo Co., Ltd.) while maintaining the temperature at 90 to 95 ° C. After cooling to room temperature, deionized water was added to adjust the solid content concentration to 20% by mass to obtain a dispersion of release agent particles B. The volume median particle size (D ₅₀ ) of the release agent particles B in the dispersion was 0.46 μm, and the CV value was 43%.

Production Example 8
(Manufacture of dispersion liquid of release agent particles C)
In a beaker with an internal volume of 1 L, 213 g of deionized water and 5.36 g of an aqueous solution of dipotassium alkenyl succinate “Latemul ASK” (manufactured by Kao Corporation, effective concentration 28% by mass) are dissolved, and then paraffin wax “HNP-9” is dissolved therein. 35 g (manufactured by Nippon Seiki Co., Ltd., melting point 75 ° C.) and 15 g of silica fine particles “AEROSIL R972” (manufactured by Nippon Aerosil Co., Ltd., specific gravity: 2.2, average primary particle size: 16 nm, hydrophobizing agent: dimethyldichlorosilane) The mixture was stirred with a homomixer while maintaining the temperature at 95 to 98 ° C. to obtain a preliminary dispersion.
The obtained preliminary dispersion was further treated twice at a pressure of 20 MPa using a high-pressure wet atomizer “Nanomizer NM2-L200-D08” (manufactured by Yoshida Kikai Kogyo Co., Ltd.) while maintaining the temperature at 90 to 95 ° C. After cooling to room temperature, deionized water was added to adjust the solid content concentration to 20% by mass to obtain a dispersion of release agent particles C. The volume median particle size (D ₅₀ ) of the release agent particles C in the dispersion was 0.57 μm, and the CV value was 49%.

Production Example 9
(Manufacture of dispersion liquid of release agent particles D)
In a beaker with an internal volume of 1 L, 213 g of deionized water and 5.36 g of an aqueous solution of dipotassium alkenyl succinate “Latemul ASK” (manufactured by Kao Corporation, effective concentration 28% by mass) are dissolved, and then paraffin wax “HNP-9” is dissolved therein. 45 g (manufactured by Nippon Seiki Co., Ltd., melting point 75 ° C.) and 5 g of titanium oxide fine particles “JMT150-IB” (manufactured by Teika, specific gravity: 4.2, average primary particle size: 15 nm, hydrophobizing agent: isobutylsilane) The mixture was stirred with a homomixer while maintaining the temperature at 95 to 98 ° C. to obtain a preliminary dispersion.
The obtained preliminary dispersion was further treated twice at a pressure of 20 MPa using a high-pressure wet atomization apparatus “Nanomizer NM2-L200-D08” (manufactured by Yoshida Kikai Kogyo Co., Ltd.) while maintaining the temperature at 90 to 95 ° C. After cooling to room temperature, deionized water was added to adjust the solid content concentration to 20% by mass, and a dispersion of release agent particles D was obtained. The volume median particle size (D ₅₀ ) of the release agent particles D in the dispersion was 0.49 μm, and the CV value was 44%.

Production Example 10
(Manufacture of dispersion liquid of release agent particles E)
In a beaker with an internal volume of 1 L, 213 g of deionized water and 5.36 g of an aqueous solution of dipotassium alkenyl succinate “Latemul ASK” (manufactured by Kao Corporation, effective concentration 28% by mass) are dissolved, and then paraffin wax “HNP-9” is dissolved therein. 45 g (manufactured by Nippon Seiki Co., Ltd., melting point 75 ° C.) and 5 g of aluminum oxide fine particles “AEROXIDE Alu C805” (manufactured by Nippon Aerosil Co., Ltd., specific gravity: 4.0, average primary particle size: 13 nm, hydrophobizing agent: octylsilane) The mixture was added and stirred with a homomixer while maintaining the temperature at 95 to 98 ° C. to obtain a preliminary dispersion.
The obtained preliminary dispersion was further treated twice at a pressure of 20 MPa using a high-pressure wet atomizer “Nanomizer NM2-L200-D08” (manufactured by Yoshida Kikai Kogyo Co., Ltd.) while maintaining the temperature at 90 to 95 ° C. After cooling to room temperature, deionized water was added to adjust the solid content concentration to 20% by mass to obtain a dispersion of release agent particles E. The volume median particle size (D ₅₀ ) of the release agent particles E in the dispersion was 0.51 μm, and the CV value was 45%.

Production Example 11
(Manufacture of dispersion liquid of release agent particles F)
In a beaker with an internal volume of 1 L, 213 g of deionized water and 5.36 g of an aqueous solution of dipotassium alkenyl succinate “Latemul ASK” (manufactured by Kao Corporation, effective concentration 28% by mass) are dissolved, and then paraffin wax “HNP-9” is dissolved therein. 40 g (manufactured by Nippon Seiki Co., Ltd., melting point 75 ° C.) and 10 g of silica fine particles “AEROSIL R972” (manufactured by Nippon Aerosil Co., Ltd., specific gravity: 2.2, average primary particle size: 16 nm, hydrophobizing agent: dimethyldichlorosilane) The mixture was stirred with a homomixer while maintaining the temperature at 95 to 98 ° C. to obtain a preliminary dispersion.
While maintaining the temperature of the obtained preliminary dispersion at 90 to 95 ° C., using an ultrasonic homogenizer “US-600T” (manufactured by Nippon Seiki Co., Ltd.), the dispersion was subjected to a dispersion treatment for 30 minutes and then cooled to room temperature. Deionized water was added to adjust the solid content concentration to 20% by mass, and a dispersion of release agent particles F was obtained. The volume median particle size (D ₅₀ ) of the release agent particles F in the dispersion was 0.56 μm, and the CV value was 54%.

Production Example 12
(Production of dispersion of release agent particles G)
In a beaker having an internal volume of 1 L, 213 g of deionized water and 5.36 g of a dipotassium alkenyl succinate aqueous solution “Latemul ASK” (manufactured by Kao Corporation, effective concentration: 28% by mass) were dissolved, and then paraffin wax “HNP-11” was dissolved therein. 40 g (manufactured by Nippon Seiki Co., Ltd., melting point 68 ° C.) and 10 g of silica fine particles “AEROSIL R972” (manufactured by Nippon Aerosil Co., Ltd., specific gravity: 2.2, average primary particle size: 16 nm, hydrophobizing agent: dimethyldichlorosilane) The mixture was stirred with a homomixer while maintaining the temperature at 95 to 98 ° C. to obtain a preliminary dispersion.
The obtained preliminary dispersion was further treated twice at a pressure of 20 MPa using a high-pressure wet atomizer “Nanomizer NM2-L200-D08” (manufactured by Yoshida Kikai Kogyo Co., Ltd.) while maintaining the temperature at 90 to 95 ° C. After cooling to room temperature, deionized water was added to adjust the solid content concentration to 20% by mass, and a dispersion of release agent particles G was obtained. The volume median particle size (D ₅₀ ) of the release agent particles G in the dispersion was 0.49 μm, and the CV value was 45%.

Production Example 13
(Manufacture of dispersion liquid of release agent particles H)
In a beaker having an internal volume of 1 L, 213 g of deionized water and 5.36 g of an aqueous solution of dipotassium alkenyl succinate “Latemul ASK” (available from Kao Corporation, effective concentration: 28% by mass) were dissolved, and then paraffin wax “HNP-9” was dissolved therein. 40 g (manufactured by Nippon Seiki Co., Ltd., melting point 75 ° C.) and 10 g of silica fine particles “AEROSIL RY50” (manufactured by Nippon Aerosil Co., Ltd., specific gravity: 2.2, average primary particle size: 40 nm, hydrophobizing agent: dimethyl silicone oil) The mixture was stirred with a homomixer while maintaining the temperature at 95 to 98 ° C. to obtain a preliminary dispersion.
The obtained preliminary dispersion was further treated twice at a pressure of 20 MPa using a high-pressure wet atomizer “Nanomizer NM2-L200-D08” (manufactured by Yoshida Kikai Kogyo Co., Ltd.) while maintaining the temperature at 90 to 95 ° C. After cooling to room temperature, deionized water was added to adjust the solid content concentration to 20% by mass to obtain a dispersion of release agent particles H. The volume median particle size (D ₅₀ ) of the release agent particles H in the dispersion was 0.56 μm, and the CV value was 48%.

Production Example 14
(Production of dispersion of release agent particles I)
In a beaker having an internal volume of 1 L, 213 g of deionized water and 5.36 g of an aqueous solution of dipotassium alkenyl succinate “Latemul ASK” (available from Kao Corporation, effective concentration: 28% by mass) were dissolved, and then paraffin wax “HNP-9” was dissolved therein. 50 g (manufactured by Nippon Seiki Co., Ltd., melting point: 75 ° C.) was added and stirred with a homomixer while maintaining the temperature at 95 to 98 ° C. to obtain a preliminary dispersion.
The obtained preliminary dispersion was further treated twice at a pressure of 20 MPa using a high-pressure wet atomizer “Nanomizer NM2-L200-D08” (manufactured by Yoshida Kikai Kogyo Co., Ltd.) while maintaining the temperature at 90 to 95 ° C. After cooling to room temperature, deionized water was added to adjust the solid content concentration to 20% by mass to obtain a dispersion of release agent particles I. The volume median particle size (D ₅₀ ) of the release agent particles I in the dispersion was 0.44 μm, and the CV value was 40%.

Production Example 15
(Manufacture of dispersion liquid of release agent particles J)
In a beaker having an internal volume of 1 L, 213 g of deionized water and 3.8 g of a sodium acrylate-sodium maleate copolymer aqueous solution “Poise 521” (manufactured by Kao Corporation, effective concentration 40% by mass) were dissolved, 5 g of crystalline polyester X3, 45 g of paraffin wax “HNP-9” (manufactured by Nippon Seiki Co., Ltd., melting point 75 ° C.), and 2.5 g of 5% by mass potassium hydroxide aqueous solution are added, and the temperature is maintained at 95 to 98 ° C. The mixture was melted and stirred to obtain a molten mixture in which the polyester resin and the paraffin wax were fused together.
While maintaining the temperature of the aqueous solution containing the obtained molten mixture at 90 to 95 ° C., using a high-pressure wet atomizer “Nanomizer NM2-L200-D08” (manufactured by Yoshida Kikai Kogyo Co., Ltd.) at a pressure of 20 MPa After treating twice, it cooled to room temperature, deionized water was added, solid content concentration was adjusted to 20 mass%, and the dispersion liquid of the mold release agent particle | grains J was obtained. The volume median particle size (D ₅₀ ) of the release agent particles J in the dispersion was 0.46 μm, and the CV value was 43%.

[Production of toner]
Example 1
(Preparation of Toner 1)
<Step (2): Production of Aggregated Particle (1)>
Into a 3 L four-necked flask equipped with a dehydration tube, a stirrer, and a thermocouple, 250 g of a dispersion of resin particles Y1, 25 g of deionized water, and 31 g of a dispersion of release agent particles A were placed, and the temperature was 25 ° C. Mixed. Next, while stirring at 25 ° C., an aqueous solution obtained by dissolving 18 g of ammonium sulfate in 137 g of deionized water was dropped at 25 ° C. over 5 minutes, and then the temperature of the mixture was increased to 57 ° C. The dispersion was kept at 57 ° C. until the diameter (D ₅₀ ) reached 4.4 μm to obtain a dispersion containing aggregated particles (1).
<Step (3): Production of Aggregated Particle (2)>
After the temperature of the dispersion (total amount) of the aggregated particles (1) obtained in the step (2) is cooled to 55 ° C., 82 g of the dispersion of the resin particles Y2 is added every minute while the temperature is raised at a rate of 1 ° C./hour. The solution was dropped at a rate of 0.5 mL to obtain a dispersion containing aggregated particles (2). Moreover, the temperature of the dispersion liquid after completion | finish of dripping was 58 degreeC. The volume-average particle size (D ₅₀ ) of the obtained aggregated particles (2) was 4.9 μm.
<Step (4): Preparation of fused particles>
To the dispersion (total amount) of the aggregated particles (2) obtained in the step (2), an aqueous solution of polyoxyethylene lauryl ether sodium sulfate “Emar E-27C” (anionic surfactant, manufactured by Kao Corporation, effective concentration 27 mass) %) After adding an aqueous solution in which 14 g is mixed with 1120 g of deionized water, the temperature is raised to 80 ° C. and held at 80 ° C. for 1 hour to fuse the agglomerated particles (2) and include the fused particles. A dispersion was obtained. Then, it cooled to 30 degreeC.
<Post-processing process>
The dispersion of fused particles obtained in step (3) is cooled to 30 ° C., the solid content is separated by suction filtration, washed with deionized water, and the vacuum low-temperature dryer “DRV622DA” (manufactured by ADVANTEC Toyo Co., Ltd.). ) At 33 ° C. to obtain toner particles. Table 3 shows the volume-median particle size (D ₅₀ ), CV value, and circularity of the obtained toner particles. To 100 parts by mass of the toner particles, 2.5 parts by mass of hydrophobic silica “AEROSIL RY50” (manufactured by Nippon Aerosil Co., Ltd., average primary particle size: 40 nm) and hydrophobic silica “Cabosea TS720” (manufactured by Cabot, average) Toner 1 was obtained by putting 1.0 part by mass of a primary particle size (12 nm) into a Henschel mixer, stirring, and passing through a 150-mesh sieve. Table 2 shows the physical properties and evaluation of the obtained toner.

Example 2
(Preparation of Toner 2)
In Example 1, toner 2 was prepared in the same manner as in Example 1 except that 28 g of deionized water and 31 g of the dispersion liquid of the release agent particles A were changed to 28 g of the dispersion liquid of the release agent particles B. Obtained. Table 2 shows the physical properties and evaluation of the obtained toner.

Example 3
(Preparation of Toner 3)
In Example 1, the toner 3 was prepared in the same manner as in Example 1 except that the deionized water was changed to 21 g, and the dispersion liquid 31 of the release agent particles A was changed to the dispersion liquid 36 g of the release agent particles C. Obtained. Table 2 shows the physical properties and evaluation of the obtained toner.

Example 4
(Preparation of Toner 4)
In Example 1, toner 4 was prepared in the same manner as in Example 1 except that 28 g of deionized water and 31 g of the dispersion liquid of the release agent particles A were changed to 28 g of the dispersion liquid of the release agent particles D. Obtained. Table 2 shows the physical properties and evaluation of the obtained toner.

Example 5
(Preparation of Toner 5)
In Example 1, the toner 5 was prepared in the same manner as in Example 1 except that deionized water was changed to 28 g, and the dispersion liquid of the release agent particles A was changed to 28 g of the dispersion liquid of the release agent particles E. Obtained. Table 2 shows the physical properties and evaluation of the obtained toner.

Examples 6-8
(Production of toners 6 to 8)
Toners 6 to 8 were obtained in the same manner as in Example 1 except that the release agent particle A dispersion in Example 1 was changed to the release agent particle dispersion shown in Table 2. Table 2 shows the physical properties and evaluation of the obtained toner.

Comparative Example 1
(Preparation of Toner 9)
In Example 1, toner 9 was prepared in the same manner as in Example 1 except that deionized water was changed to 30 g, and the dispersion liquid of release agent particles A was changed to 25 g of dispersion liquid of release agent particles I. Obtained. Table 2 shows the physical properties and evaluation of the obtained toner.

Comparative Example 2
(Production of Toner 10)
In Example 1, the toner 10 was prepared in the same manner as in Example 1 except that 28 g of deionized water and 31 g of the dispersion liquid of the release agent particles A were changed to 28 g of the dispersion liquid of the release agent particles J. Obtained. Table 2 shows the physical properties and evaluation of the obtained toner.

  From Table 2, it can be seen that the toners of Examples 1 to 8 have a sufficient fixing width showing the fixability and excellent chargeability as compared with the toners of Comparative Examples 1 and 2. In Comparative Example 1, an offset was observed in all temperature ranges, and the fixing width was not shown.

  Since the electrophotographic toner obtained by the production method of the present invention is excellent in fixability and chargeability, it can be suitably used as an electrophotographic toner used in electrophotography, electrostatic recording method, electrostatic printing method and the like. According to the method of the present invention, a toner having such characteristics can be produced efficiently.

Claims (10)

The next step (1) to (4) only contains,
A method for producing an electrophotographic toner, wherein the mass ratio of the wax and the inorganic fine particles in step (1) (the mass of the wax / the mass of the inorganic fine particles) is 90/10 to 60/40 .
Step (1): Step of preparing release agent particles containing wax and inorganic fine particles Step (2): Release agent particles obtained in Step (1), resin particles (A), and aggregating agent, Step of obtaining aggregated particles (1) by mixing in an aqueous medium Step (3): Step of adding resin particles (B) to an aqueous medium containing aggregated particles (1) to obtain aggregated particles (2) 4): Step of fusing the agglomerated particles (2) to obtain fused particles   The method for producing an electrophotographic toner according to claim 1, wherein the wax includes paraffin wax. The method for producing an electrophotographic toner according to claim 1 or 2, wherein the step (1) is a step of preparing release agent particles by dispersing wax and inorganic fine particles in an aqueous medium.   The method for producing an electrophotographic toner according to claim 1, wherein the inorganic fine particles have an average primary particle size of 5 nm to 90 nm.   The method for producing an electrophotographic toner according to claim 1, wherein the inorganic fine particles have a specific gravity of 1.3 or more and 5 or less. The method for producing an electrophotographic toner according to claim 1, wherein the release agent particles have a volume-median particle size (D ₅₀ ) of 0.1 μm or more and 1 μm or less. The surface of the inorganic fine particles are hydrophobized, manufacturing method of toner for electrophotography according to any one of claims 1-6. The resin particles (A) and (B), both of which contain more than 80 wt% of the polyester resin, the production method of toner for electrophotography according to any one of claims 1-7. The method for producing an electrophotographic toner according to claim 8 , wherein the content of the amorphous polyester resin in the polyester resin in the resin particles (A) is 80 to 100% by mass. The resin particles (A) contains a coloring agent, production method of toner for electrophotography according to any one of claims 1-9.