Method of manufacturing electrostatic image developing toner

Abstract

To provide a method of manufacturing an electrostatic image developing toner that offers superior charging stability.SOLUTION: A method of manufacturing an electrostatic image developing toner is provided, the method comprising a step 1 of adding an aqueous solution of a water-soluble addition polymer F of an aromatic group-containing monomer and a hydrophilic monomer to agglomerate resin particles containing crystalline polyester resin in an aqueous medium so as to obtain agglomerated particles, and a step 2 of fusing the agglomerated particles obtained in the step 1 to obtain fused particles.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing a toner for developing electrostatic images. [Background technology]

[0002] In the field of electrophotography, with the development of electrophotographic systems, there is a demand for the development of electrophotographic toners that can meet the demands for higher image quality and higher speeds.To meet the demands for higher image quality, a method for obtaining toners with a narrow particle size distribution and small particle size has been adopted, in which toners are obtained by aggregating and fusing fine resin particles or the like in an aqueous medium, using an aggregation-coalescence method (emulsion aggregation method, aggregation-fusion method).

[0003] For example, Patent Document 1 discloses a toner for developing electrostatic images, which has excellent low-temperature fixing properties and charge stability, and further has excellent image density of printed matter, and which contains toner particles with a core-shell structure having a core and a shell, and the core is composed of a styrene-based resin (AS), a polyester segment (CH-1) which is a polycondensation moiety of an alcohol component (C-al) containing 95 mol % to 100 mol % of 1,4-butanediol, and a carboxylic acid component (C-ac) containing 95 mol % to 100 mol % of an aliphatic dicarboxylic acid compound having 12 to 16 carbon atoms, and and a crystalline composite resin (CH) containing a vinyl resin segment (CH-2) which is an addition polymerization portion of a monomer component (Ch-st) containing an alkylene oxide adduct of bisphenol A, and the shell contains a polyester segment (AH-1) which is a polycondensation portion of an alcohol component (A-al) containing an alkylene oxide adduct of bisphenol A and a carboxylic acid component (A-ac) containing 5 mol % to 40 mol % of succinic acid, and an amorphous composite resin (AH) containing a vinyl resin segment (AH-2) which is an addition polymerization portion of a monomer component (A-st) containing a styrene compound. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-76891 Summary of the Invention [Problem to be solved by the invention]

[0005] However, it was found that there is room for further improvement in the charging stability of the toner manufacturing method using the aggregation and fusion method. The present invention relates to a method for producing a toner for developing electrostatic images, which toner has a narrow charge distribution and excellent charge stability. [Means for solving the problem]

[0006] The present inventors have discovered that the charging stability of the electrostatic image developing toner obtained by a method for producing the electrostatic image developing toner, which includes an aggregation step and a fusion step, can be improved by adding an aqueous solution of a water-soluble addition polymer F of an aromatic group-containing monomer and a hydrophilic monomer in the aggregation step. That is, the present invention relates to the following [1]. [1] A method for producing a toner for developing electrostatic images, comprising the following steps 1 and 2 in this order: Step 1: A step of adding an aqueous solution of a water-soluble addition polymer F of an aromatic group-containing monomer and a hydrophilic monomer to agglomerate resin particles containing a crystalline polyester resin in an aqueous medium to obtain agglomerated particles. Step 2: A step of fusing the aggregated particles obtained in step 1 to obtain fused particles. [Effects of the Invention]

[0007] According to the present invention, there is provided a method for producing a toner for developing electrostatic images, which produces a toner having excellent charge stability. DETAILED DESCRIPTION OF THE INVENTION

[0008] [Method of manufacturing electrostatic image developing toner] The method for producing a toner for developing electrostatic images of the present invention includes the following steps 1 and 2 in this order. Step 1: A step of adding an aqueous solution of a water-soluble addition polymer F of an aromatic group-containing monomer and a hydrophilic monomer to agglomerate resin particles containing a crystalline polyester resin in an aqueous medium to obtain agglomerated particles. Step 2: A step of fusing the aggregated particles obtained in step 1 to obtain fused particles. Hereinafter, the method for producing a toner for developing electrostatic images of the present invention may be simply referred to as the "production method of the present invention." The toner for developing electrostatic images obtained by the production method of the present invention may be simply referred to as the "toner." The water-soluble addition polymer F of an aromatic group-containing monomer and a hydrophilic monomer may be simply referred to as the "water-soluble addition polymer F."

[0009] According to the manufacturing method of the present invention, it is possible to obtain a toner having excellent charge stability. The reason why the above-mentioned effect is obtained is not clear, but is thought to be as follows. Typically, when a toner containing a crystalline polyester resin is produced in an aqueous medium by emulsion aggregation, a resin particle dispersion containing the crystalline polyester resin is prepared and then mixed and aggregated with a dispersion of other toner raw materials. However, because crystalline polyester resin is highly hydrophobic and has poor stability in an aqueous medium, aggregation of the crystalline polyester resin particles tends to occur first during aggregation. This results in variations in the crystalline polyester resin content among the resulting toner particles, which tends to result in a broad distribution of charge amounts in the resulting toner. On the other hand, in the present invention, by adding an aqueous solution of a water-soluble addition polymer F of an aromatic group-containing monomer and a hydrophilic monomer during the aggregation of resin particles in step 1, the water-soluble addition polymer F is adsorbed at multiple points to the surfaces of resin particles containing a highly hydrophobic crystalline polyester via the structural units derived from the aromatic group-containing monomer, and the dispersion of the resin particles in the aqueous medium is stabilized by the structural units derived from the hydrophilic monomer of the water-soluble addition polymer F. This brings the dispersibility of the resin particles closer to that of dispersions of other toner raw material components, thereby suppressing compositional variation among aggregated particles, narrowing the charge distribution of the resulting toner, and improving charge stability. The above-mentioned mechanism regarding the effects of the present invention is only a supposition, and the present invention is not limited to this.

[0010] The definitions of various terms used in this specification are shown below. Regarding the "water solubility" of a polymer, when a polymer that has reached a constant weight after drying at 105°C for 2 hours is dissolved in 100 g of water at 25°C until it reaches saturation, the polymer is deemed to be water soluble if the amount dissolved exceeds 10 g. If the water-insoluble polymer is an anionic polymer, the amount dissolved is the amount dissolved when the anionic groups of the polymer are 100% neutralized with sodium hydroxide. The "hydrophilicity" of a monomer means that when the monomer is dissolved in 100 g of deionized water at 25°C until saturation, the resulting dissolved amount is 10 g or more. The dissolved amount of a hydrophilic monomer is preferably 50 g or more. In the case of a monomer having an ionic functional group, the "hydrophilicity" means that the dissolved amount is within the above range when the ionic functional group is neutralized. With respect to hydrocarbon groups, the parenthetical expressions "(iso or tertiary)" and "(iso)" refer to both the presence and absence of these prefixes; the absence of these prefixes indicates normal. "(Meth)acrylic acid" means at least one selected from acrylic acid and methacrylic acid, and "(meth)acrylate" means at least one selected from acrylate and methacrylate. "Styrenic compound" means unsubstituted or substituted styrene. Whether a resin is crystalline or amorphous is determined by its crystallinity index. The crystallinity index is defined as the ratio of the softening point of the resin to the endothermic maximum peak temperature (softening point (°C) / endothermic maximum peak temperature (°C)) measured by the method described in the Examples below. A crystalline resin is one whose crystallinity index is 0.6 or more and 1.4 or less. An amorphous resin is one whose crystallinity index is less than 0.6 or more than 1.4. The crystallinity index can be adjusted appropriately by adjusting the types and ratios of raw material monomers, as well as production conditions such as reaction temperature, reaction time, and cooling rate. The carboxylic acid component of the polyester resin includes not only the compound itself, but also anhydrides that decompose during the reaction to produce an acid, and alkyl esters of each carboxylic acid (the alkyl group has 1 to 3 carbon atoms). Volume median particle size (D 50 )" is the particle size at which the cumulative volume frequency calculated by volume fraction is 50% calculated from the smallest particle size. The coefficient of variation of particle size distribution (hereinafter also simply referred to as "CV value") is a value expressed by the following formula: In the following formula, the volume average particle size is the particle size obtained by multiplying the particle size measured on a volume basis by the proportion of particles having that particle size value, and dividing the resulting value by the number of particles. CV value (%) = [Standard deviation of particle size distribution (μm) / Volume average particle size (μm)] x 100

[0011] <Process 1> In step 1, an aqueous solution of a water-soluble addition polymer F of an aromatic group-containing monomer and a hydrophilic monomer is added to aggregate resin particles containing a crystalline polyester resin in an aqueous medium to obtain aggregated particles. The aggregated particles obtained in step 1 include aggregated particles 1 obtained by aggregating resin particles in an aqueous medium, and aggregated particles 2 obtained by using aggregated particles 1 as cores and attaching shell resin particles containing an amorphous resin to the cores in an aqueous medium, followed by aggregating the cores. In this specification, the term "aggregated particles" simply refers to aggregated particles 1 or 2. In step 1, it is preferable to obtain aggregated particles 1 by aggregating colorant particles and release agent particles in addition to resin particles, and it is more preferable to mix a resin particle dispersion, a colorant particle dispersion, and a release agent particle dispersion and aggregate these particles by aggregating them to obtain aggregated particles 1.

[0012] [Resin particles] The resin particle dispersion used in step 1 contains resin particles containing a crystalline polyester resin. The resin particles may contain an amorphous resin A in the same or different resin particles in addition to the crystalline polyester resin.

[0013] <Crystalline polyester resin> The crystalline polyester resin is, for example, a polycondensate of an alcohol component and a carboxylic acid component. The crystalline polyester resin is a polycondensation product of an alcohol component and a carboxylic acid component. The alcohol component is preferably an α,ω-aliphatic diol. The α,ω-aliphatic diol preferably has 2 or more carbon atoms, and preferably 16 or less, more preferably 14 or less, and even more preferably 12 or less carbon atoms. Examples of α,ω-aliphatic diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, and 1,14-tetradecanediol. Among these, at least one selected from ethylene glycol, 1,6-hexanediol, 1,10-decanediol, and 1,12-dodecanediol is preferred, and at least one selected from ethylene glycol and 1,10-decanediol is more preferred.

[0014] The amount of α,ω-aliphatic diol in the alcohol component is preferably 80 mol% or more, more preferably 85 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, and preferably 100 mol% or less, even more preferably 100 mol%.

[0015] The alcohol component may contain other alcohol components different from the α,ω-aliphatic diol. Examples of other alcohol components include aliphatic diols other than α,ω-aliphatic diols, such as 1,2-propanediol and neopentyl glycol; aromatic diols, such as alkylene oxide adducts of bisphenol A; and trihydric or higher alcohols, such as glycerin, pentaerythritol, and trimethylolpropane. These alcohol components may be used alone or in combination.

[0016] The carboxylic acid component is preferably an aliphatic dicarboxylic acid, more preferably a straight-chain aliphatic dicarboxylic acid. The aliphatic dicarboxylic acid preferably has 4 or more carbon atoms, more preferably 8 or more carbon atoms, and even more preferably 10 or more carbon atoms, and preferably has 14 or less carbon atoms, more preferably 12 or less carbon atoms. Examples of aliphatic dicarboxylic acids include fumaric acid, sebacic acid, dodecanedioic acid, and tetradecanedioic acid. Among these, at least one selected from sebacic acid and dodecanedioic acid is preferred. These carboxylic acid components may be used alone or in combination.

[0017] The amount of aliphatic dicarboxylic acid in the carboxylic acid component is preferably 80 mol% or more, more preferably 85 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, and is preferably 100 mol% or less, even more preferably 100 mol%.

[0018] The carboxylic acid component may contain other carboxylic acid components different from the aliphatic dicarboxylic acid. Examples of other carboxylic acid components include aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid, and polycarboxylic acids having three or more carboxylic acids. These carboxylic acid components may be used alone or in combination.

[0019] The equivalent ratio of the carboxyl groups of the carboxylic acid component to the hydroxyl groups of the alcohol component [COOH groups / OH groups] is preferably 0.7 or more, more preferably 0.8 or more, and is preferably 1.3 or less, more preferably 1.2 or less.

[0020] <Method for producing crystalline polyester resin> The crystalline polyester resin can be produced, for example, by polycondensing raw material monomers containing an alcohol component and a carboxylic acid component. The polycondensation of the alcohol component and the carboxylic acid component can be carried out, for example, in an inert gas atmosphere, in the presence of an esterification catalyst, an esterification promoter, a polymerization inhibitor, etc., as necessary, at a temperature of about 120°C or higher and 250°C or lower. Examples of the esterification catalyst include tin compounds such as dibutyltin oxide and tin(II) di(2-ethylhexanoate), and titanium compounds such as titanium diisopropoxybis(triethanolaminate). Examples of the esterification co-catalyst that can be used together with the esterification catalyst include gallic acid (3,4,5-trihydroxybenzoic acid). The amount of the esterification catalyst used is preferably 0.01 parts by mass or more and 10 parts by mass or less relative to 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component, which are raw material monomers for the polyester resin. The amount of the esterification promoter used is preferably 0.001 part by mass or more and 1 part by mass or less relative to 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. Furthermore, examples of the polymerization inhibitor include radical polymerization inhibitors such as 4-tert-butylcatechol. When a polymerization inhibitor is used, the amount of the polymerization inhibitor used is preferably 0.001 part by mass or more and 1 part by mass or less per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component.

[0021] <Physical properties of crystalline polyester resin> The softening point of the crystalline polyester resin is preferably 60°C or higher, more preferably 70°C or higher, and even more preferably 80°C or higher from the viewpoint of heat-resistant storage stability, and is preferably 150°C or lower, more preferably 120°C or lower, and even more preferably 100°C or lower from the viewpoint of low-temperature fixability. The melting point of the crystalline polyester resin is preferably 50°C or higher, more preferably 60°C or higher, and even more preferably 70°C or higher from the viewpoint of heat-resistant storage stability, and is preferably 120°C or lower, more preferably 100°C or lower, and even more preferably 90°C or lower from the viewpoint of low-temperature fixability.

[0022] The acid value of the crystalline polyester resin is preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g or more, and preferably 35 mgKOH / g or less, more preferably 25 mgKOH / g or less, and even more preferably 20 mgKOH / g or less. The softening point, melting point, and acid value of the crystalline polyester resin can be appropriately adjusted by the type and amount of raw material monomers, as well as production conditions such as reaction temperature, reaction time, and cooling rate, and are determined by the method described in the Examples. When two or more crystalline polyester resins are used in combination, it is preferable that the softening point, melting point, and acid value of the mixture thereof are each within the above-mentioned ranges.

[0023] From the viewpoint of low-temperature fixability, the content of the crystalline polyester resin in the toner particles is preferably 1% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, and is preferably 40% by mass or less, more preferably 35% by mass or less, even more preferably 30% by mass or less.

[0024] <Amorphous resin A> In the present invention, the binder resin preferably contains an amorphous resin A. Hereinafter, the amorphous resin A may be simply referred to as "resin A." Resin A is, for example, an amorphous polyester resin containing a polycondensate of an alcohol component and a carboxylic acid component, or a styrene-acrylic resin. Examples of amorphous polyester resins include polyester resins and modified polyester resins, such as urethane-modified polyester resins, epoxy-modified polyester resins, and composite resins containing polyester resin segments and addition-polymerized resin segments.

[0025] (amorphous polyester resin) Examples of the alcohol component of the amorphous polyester resin include aliphatic diols, alkylene oxide adducts of aromatic diols, alicyclic diols, and trihydric or higher polyhydric alcohols. Among these, alkylene oxide adducts of aliphatic diols and aromatic diols are preferred.

[0026] Examples of aliphatic diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, and 3-methyl-1,5-pentanediol, and 2,2-dimethyl-1,3-propanediol (neopentyl glycol) is preferred. When the alcohol component contains an aliphatic diol, the content of the aliphatic diol in the alcohol component is preferably 60 mol % or more, more preferably 80 mol % or more, and even more preferably 90 mol % or more, and 100 mol % or less.

[0027] The alkylene oxide adduct of an aromatic diol is preferably an alkylene oxide adduct of bisphenol A, more preferably an alkylene oxide adduct of formula (I):

[0028] [ka] (wherein OR1 and R2O are oxyalkylene groups, R1 and R2 each independently represent an ethylene group or a propylene group, x and y represent the average number of moles of alkylene oxide added and are each positive numbers, and the sum of x and y is 1 or more, preferably 1.5 or more, and 16 or less, preferably 8 or less, and more preferably 4 or less).

[0029] Examples of the alkylene oxide adduct of bisphenol A represented by formula (I) include a propylene oxide adduct of bisphenol A and an ethylene oxide adduct of bisphenol A. When the alcohol component contains an alkylene oxide adduct of bisphenol A, the content of the alkylene oxide adduct of bisphenol A in the alcohol component is preferably 60 mol% or more, more preferably 80 mol% or more, and even more preferably 90 mol% or more, and 100 mol% or less.

[0030] Examples of alicyclic diols include hydrogenated bisphenol A [2,2-bis(4-hydroxycyclohexyl)propane] and adducts of hydrogenated bisphenol A with alkylene oxides having 2 to 4 carbon atoms (average number of added moles: 2 to 12).

[0031] Examples of trihydric or higher polyhydric alcohols include glycerin, pentaerythritol, trimethylolpropane, and sorbitol. These alcohol components may be used alone or in combination of two or more.

[0032] Examples of the carboxylic acid component of the amorphous polyester resin include dicarboxylic acids and trivalent or higher polycarboxylic acids.

[0033] Examples of dicarboxylic acids include aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and alicyclic dicarboxylic acids. Among these, at least one selected from aromatic dicarboxylic acids and aliphatic dicarboxylic acids is preferred.

[0034] Examples of aromatic dicarboxylic acids include phthalic acid, isophthalic acid, and terephthalic acid. Among these, at least one selected from isophthalic acid and terephthalic acid is preferred. The amount of the aromatic dicarboxylic acid in the carboxylic acid component is preferably 30 mol % or more, more preferably 40 mol % or more, even more preferably 50 mol % or more, and preferably 100 mol % or less.

[0035] The aliphatic dicarboxylic acid preferably has 2 or more carbon atoms, more preferably 3 or more carbon atoms, and preferably has 30 or less carbon atoms, more preferably 20 or less carbon atoms. Examples of aliphatic dicarboxylic acids include oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid, sebacic acid, dodecanedioic acid, azelaic acid, and succinic acids substituted with an aliphatic hydrocarbon group having from 1 to 20 carbon atoms. Examples of succinic acids substituted with an aliphatic hydrocarbon group having from 1 to 20 carbon atoms include dodecylsuccinic acid, dodecenylsuccinic acid, and octenylsuccinic acid. Among these, at least one selected from fumaric acid, sebacic acid, adipic acid, and succinic acids substituted with an aliphatic hydrocarbon group having from 1 to 20 carbon atoms is preferred, at least one selected from fumaric acid and adipic acid is more preferred, and adipic acid is even more preferred. When the carboxylic acid component contains an aliphatic dicarboxylic acid, the amount of the aliphatic dicarboxylic acid in the carboxylic acid component is preferably 5 mol% or more, more preferably 10 mol% or more, even more preferably 15 mol% or more, and preferably 50 mol% or less, more preferably 45 mol% or less, even more preferably 40 mol% or less.

[0036] An example of the alicyclic dicarboxylic acid is cyclohexanedicarboxylic acid.

[0037] The trivalent or higher polyvalent carboxylic acid is preferably a trivalent carboxylic acid, such as trimellitic acid. When the carboxylic acid component contains a trivalent or higher polycarboxylic acid, the amount of the trivalent or higher polycarboxylic acid in the carboxylic acid component is preferably 3 mol% or more, more preferably 5 mol% or more, even more preferably 7 mol% or more, and is preferably 25 mol% or less, more preferably 20 mol% or less, even more preferably 15 mol% or less. These carboxylic acid components may be used alone or in combination of two or more.

[0038] The equivalent ratio of the carboxyl groups of the carboxylic acid component to the hydroxyl groups of the alcohol component [COOH groups / OH groups] is preferably 0.7 or more, more preferably 0.8 or more, and is preferably 1.3 or less, more preferably 1.2 or less.

[0039] Resin A can be produced, for example, in the same manner as the above-mentioned crystalline polyester resin.

[0040] <Physical properties of amorphous resin A> The softening point of Resin A is preferably 70°C or higher, more preferably 85°C or higher, even more preferably 95°C or higher, and preferably 140°C or lower, more preferably 130°C or lower, even more preferably 120°C or lower. The glass transition temperature of Resin A is preferably 35°C or higher, more preferably 40°C or higher, even more preferably 45°C or higher, and preferably 75°C or lower, more preferably 70°C or lower, even more preferably 65°C or lower.

[0041] The acid value of the amorphous polyester resin is preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g or more, even more preferably 15 mgKOH / g or more, and is preferably 35 mgKOH / g or less, more preferably 30 mgKOH / g or less, even more preferably 25 mgKOH / g or less.

[0042] The softening point, glass transition temperature, and acid value of Resin A can be appropriately adjusted by adjusting the types and amounts of raw material monomers used, as well as production conditions such as reaction temperature, reaction time, and cooling rate, and these values ​​can be determined by the methods described in the examples. When two or more resins A are used in combination, it is preferable that the softening point, glass transition temperature and acid value of the resulting mixture are within the above ranges.

[0043] The total content of the crystalline polyester resin and resin A in the toner particles is preferably 65% ​​by mass or more, more preferably 70% by mass or more, even more preferably 75% by mass or more, and is preferably 98% by mass or less, more preferably 95% by mass or less, even more preferably 90% by mass or less.

[0044] When the resin particles contain amorphous resin A, the mass ratio of amorphous resin A to crystalline polyester resin in the resin particles [amorphous resin A / crystalline polyester resin] is preferably 99 / 1 or less, more preferably 95 / 5 or less, even more preferably 90 / 10 or less, even more preferably 85 / 15 or less, and is preferably 60 / 40 or more, more preferably 65 / 35 or more, even more preferably 70 / 30 or more.

[0045] [Method for producing resin particle dispersion] The resin particle dispersion containing the crystalline polyester resin can be prepared by a known method, but is preferably dispersed by a phase inversion emulsification method, such as a method in which an aqueous medium is added to an organic solvent solution of the resin or a molten resin to perform phase inversion emulsification.

[0046] Examples of the aqueous medium used for phase inversion emulsification include those described below. The organic solvent used for phase inversion emulsification is not particularly limited as long as it dissolves the resin, but from the viewpoint of facilitating phase inversion, examples include alcohol-based solvents such as ethanol, isopropanol, and isobutanol; ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and diethyl ketone; ether-based solvents such as dibutyl ether, tetrahydrofuran, and dioxane; and acetate-based solvents such as ethyl acetate and isopropyl acetate. Among these, from the viewpoint of ease of removal from the mixed solution after addition of the aqueous medium, ketone-based solvents and acetate-based solvents are preferred, and methyl ethyl ketone, ethyl acetate, and isopropyl acetate are more preferred. Methyl ethyl ketone is preferred as the organic solvent for dissolving polyester-based resins, and ethyl acetate is preferred as the organic solvent for dissolving styrene-acrylic resins. It is preferable to add a neutralizing agent to the organic solvent solution of the polyester resin. Examples of the neutralizing agent include basic substances. Examples of the basic substance include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; and nitrogen-containing basic substances such as ammonia, trimethylamine, and diethanolamine. The equivalent amount (mol%) of the neutralizing agent used relative to the acid groups of the resin contained in the resin particles is preferably 10 mol% or more, more preferably 30 mol% or more, even more preferably 40 mol% or more, from the viewpoint of obtaining fine resin particles and improving dispersion stability, and is preferably 95 mol% or less, more preferably 90 mol% or less, even more preferably 85 mol% or less. The equivalent amount (mol %) of the neutralizing agent used can be calculated by the following formula: When the equivalent amount of the neutralizing agent used is 100 mol % or less, it is synonymous with the degree of neutralization. Equivalent amount of neutralizing agent used (mol%) = [{mass of neutralizing agent added (g) / equivalent amount of neutralizing agent} / [{weighted average acid value of resin constituting resin particles (mg KOH / g) × mass of resin constituting resin particles (g)} / (56 × 1000)]] × 100

[0047] While stirring the organic solvent solution or the molten resin, the aqueous medium is gradually added to cause phase inversion. The temperature of the organic solvent solution when adding the aqueous medium is preferably 50°C or higher, more preferably 60°C or higher, and preferably 90°C or lower, more preferably 85°C or lower, from the viewpoint of improving the dispersion stability of the resin particles.

[0048] After the phase inversion emulsification, if necessary, the organic solvent may be removed from the obtained dispersion by distillation, etc. In this case, the amount of the remaining organic solvent in the dispersion is preferably 1% by mass or less, more preferably 0.5% by mass or less, and even more preferably substantially 0% by mass.

[0049] The volume median diameter (D 50) is preferably 0.05 μm or more, more preferably 0.08 μm or more, even more preferably 0.10 μm or more, and is preferably 0.8 μm or less, more preferably 0.4 μm or less, even more preferably 0.3 μm or less, from the viewpoint of obtaining a toner that can produce high-quality images. From the viewpoint of obtaining a toner that can produce high-quality images, the CV value of the resin particles in the dispersion is preferably 10% or more, more preferably 20% or more, and is preferably 40% or less, more preferably 35% or less. Volume median particle size of resin particles (D 50 ) and the CV value is determined by the method described in the Examples.

[0050] From the viewpoint of improving toner productivity and dispersion stability of the resin particle dispersion, the solid content concentration of the resin particle dispersion is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and is preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 35% by mass or less. The solid content is the total amount of non-volatile components.

[0051] The resin particle dispersion containing the crystalline polyester resin and the amorphous resin A can be obtained by the same method as described above. When a resin particle dispersion containing the amorphous resin A and a resin particle dispersion containing the crystalline polyester resin are mixed and used, these resin particle dispersions can be obtained by the same method as described above.

[0052] [Aqueous medium] In the present invention, the aqueous medium is a medium containing water as a main component, and the water content in the aqueous medium is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, and 100% by mass or less. The water is preferably deionized water or distilled water. Examples of components other than water that can constitute an aqueous medium together with water include water-soluble organic solvents such as alkyl alcohols having 1 to 5 carbon atoms; dialkyl ketones having 3 to 5 carbon atoms, such as acetone and methyl ethyl ketone; and cyclic ethers, such as tetrahydrofuran.

[0053] [Water-soluble addition polymer F] The water-soluble addition polymer F is obtained by addition polymerization of an aromatic group-containing monomer and a hydrophilic monomer. The water-soluble addition polymer F may contain structural units derived from hydrophobic monomers other than the aromatic group-containing monomer.

[0054] The aromatic group-containing monomer is a vinyl monomer having an aromatic group having from 6 to 22 carbon atoms, which may have a substituent containing a hetero atom, and is more preferably one or more selected from a styrene-based monomer and an aromatic group-containing (meth)acrylate. The molecular weight of the aromatic group-containing monomer is preferably less than 500. Examples of the styrene-based monomer include styrene, α-methylstyrene, 2-methylstyrene, etc., and examples of the aromatic group-containing (meth)acrylate include benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, etc. Among these, preferred is at least one selected from styrene, α-methylstyrene, and benzyl (meth)acrylate, and more preferred is at least one selected from styrene and α-methylstyrene. The styrene-based monomers may be used alone or in combination of two or more.

[0055] Examples of hydrophilic monomers include monomers having an ionic functional group and nonionic hydrophilic monomers having no ionic functional group, with monomers having an ionic functional group being preferred. Examples of the monomer having an ionic functional group include a monomer having a cationic group and a monomer having an anionic group. From the viewpoint of improving the dispersion stability of the crystalline polyester resin particles, a monomer having an anionic group is preferred. The anionic group is a carboxy group (-COOM). 1), sulfonic acid group (-SO3M 1 ), phosphate group (-OPO3M 1 2) and the like, which exhibit acidity by dissociating and releasing a hydrogen ion, and a carboxyl group is more preferred. 1 represents a hydrogen atom, an alkali metal, ammonium, or organic ammonium. The anionic group may be in a dissociated form (e.g., -COO - , -SO3 - , -OPO3 2- , -OPO3 - M 1 ) shall be included. Examples of the monomer having a carboxy group include (meth)acrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, citraconic acid, and 2-methacryloyloxymethylsuccinic acid, with (meth)acrylic acid being preferred and acrylic acid being more preferred. Examples of the monomer having a sulfonic acid group include styrene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, and 3-sulfopropyl (meth)acrylate. Examples of the monomer having a phosphoric acid group include vinylphosphonic acid, vinyl phosphate, bis(methacryloxyethyl) phosphate, diphenyl-2-acryloyloxyethyl phosphate, and diphenyl-2-methacryloyloxyethyl phosphate. Among these, preferred are monomers having a carboxy group, more preferred are at least one selected from (meth)acrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, citraconic acid, and 2-methacryloyloxymethylsuccinic acid, even more preferred are (meth)acrylic acid, and even more preferred are acrylic acid.

[0056] Examples of nonionic hydrophilic monomers include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate and 3-hydroxypropyl (meth)acrylate; polyalkylene glycol (meth)acrylates such as polyethylene glycol (n=2 to 30, n represents the average number of moles of oxyethylene groups added. Hereinafter, n represents the average number of moles of oxyalkylene groups added.) (meth)acrylate; alkoxypolyalkylene glycol (meth)acrylates such as methoxypolyethylene glycol (n=1 to 30) (meth)acrylate; and phenoxy (ethylene glycol / propylene glycol copolymer) (n=1 to 30, ethylene glycol therein: n=1 to 29) (meth)acrylate.

[0057] Specific examples of commercially available nonionic hydrophilic monomers include NK Ester M-40G, 90G, 230G, etc. (all trade names of Shin-Nakamura Chemical Co., Ltd.), Blenmer PE-90, 200, 350, etc., Blenmer PME-100, 200, 400, etc., Blenmer 50PEP-300, Blenmer 50POEP-800B, etc. (all trade names of NOF Corporation). The hydrophilic monomers may be used alone or in combination of two or more.

[0058] The other hydrophobic monomers other than the aromatic group-containing monomers (hereinafter also simply referred to as "other hydrophobic monomers") are preferably (meth)acrylic acid esters having a hydrocarbon group derived from an aliphatic alcohol. The (meth)acrylic acid ester having a hydrocarbon group derived from an aliphatic alcohol preferably has a hydrocarbon group derived from an aliphatic alcohol having from 1 to 22 carbon atoms. Examples include (meth)acrylic acid esters having an alkyl group such as methyl (meth)acrylate, ethyl (meth)acrylate, (iso)propyl (meth)acrylate, (iso- or tertiary)butyl (meth)acrylate, (iso)amyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, (iso)octyl (meth)acrylate, (iso)decyl (meth)acrylate, (iso)dodecyl (meth)acrylate, (iso)stearyl (meth)acrylate, and cyclohexyl (meth)acrylate. Among these, more preferred are those having an alkyl group having from 1 to 10 carbon atoms, even more preferred are those having an alkyl group having from 1 to 8 carbon atoms, even more preferred are methyl (meth)acrylate and (iso- or tertiary)butyl (meth)acrylate, and particularly preferred are methyl methacrylate and n-butyl acrylate.

[0059] The contents of aromatic group-containing monomers, hydrophilic monomers, and other hydrophobic monomers in the raw material monomer mixture (content as unneutralized amounts, the same applies hereinafter) during production of water-soluble addition polymer F, or the contents of aromatic group-containing monomer-derived structural units, hydrophilic monomer-derived structural units, and other hydrophobic monomer-derived structural units in water-soluble addition polymer F, are as follows, from the viewpoint of improving the charging stability of the resulting toner. The content of the aromatic group-containing monomer component in the raw material monomer mixture is preferably 10% by mass or more, more preferably 30% by mass or more, even more preferably 50% by mass or more, and is preferably 95% by mass or less, more preferably 80% by mass or less, even more preferably 75% by mass or less. The content of the aromatic group-containing monomer-derived constituent units in the water-soluble addition polymer F is the same as the content of the aromatic group-containing monomer component in the raw material monomer mixture. The content of the hydrophilic monomer component in the raw material monomer mixture is preferably 5% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, and is preferably 70% by mass or less, more preferably 50% by mass or less, even more preferably 40% by mass or less. The content of the hydrophilic monomer-derived constitutional units in the water-soluble addition polymer F is the same as the content of the hydrophilic monomer component in the raw material monomer mixture. When the raw material monomer mixture contains other hydrophobic monomer components, the content of the other hydrophobic monomer components in the raw material monomer mixture is preferably 5% by mass or more, more preferably 20% by mass or more, even more preferably 50% by mass or more, and preferably 85% by mass or less, more preferably 80% by mass or less, even more preferably 75% by mass or less. When the water-soluble addition polymer F contains constitutional units derived from other hydrophobic monomers, the content of the constitutional units derived from other hydrophobic monomers in the water-soluble addition polymer F is the same as the content of the other hydrophobic monomer components in the raw material monomer mixture. The total of the content of the aromatic group-containing monomer component, the content of the hydrophilic monomer component, and the content of the other hydrophobic monomer component is 100% by mass.

[0060] The mass ratio of the hydrophilic monomer component to the aromatic group-containing monomer component [hydrophilic monomer component / aromatic group-containing monomer component] is preferably 0.06 or more, more preferably 0.15 or more, even more preferably 0.25 or more, still more preferably 0.35 or more, and is preferably 7 or less, more preferably 1.7 or less, even more preferably 0.80 or less.

[0061] [Method for producing water-soluble addition polymer F] The water-soluble addition polymer F is produced by copolymerizing the raw material monomer mixture by a known polymerization method such as bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, etc. Among these polymerization methods, solution polymerization is preferred. The solvent used in the solution polymerization method is not particularly limited, but a polar organic solvent is preferred. If the polar organic solvent is miscible with water, it can be used in combination with water. Examples of polar organic solvents include aliphatic alcohols having 1 to 3 carbon atoms, ketones having 3 to 5 carbon atoms, ethers, and esters such as ethyl acetate. Among these, methanol, ethanol, acetone, methyl ethyl ketone (MEK), or a mixed solvent of one or more of these with water is preferred, ethanol, methyl ethyl ketone, or a mixed solvent of these with water is preferred, and a mixed solvent of methyl ethyl ketone or ethanol with water is preferred. During the polymerization, a polymerization initiator or a polymerization chain transfer agent can be used. As the polymerization initiator, known radical polymerization initiators such as azo compounds such as 2,2'-azobisisobutyronitrile, 4,4'-azobis(4-cyanovaleric acid), and 2,2'-azobis(2,4-dimethylvaleronitrile), and organic peroxides such as tert-butyl peroxyoctoate and benzoyl peroxide can be used. One type of polymerization initiator may be used alone, or two or more types may be used in combination. The amount of radical polymerization initiator added is preferably 0.001 to 5 parts by mass, more preferably 0.01 to 3 parts by mass, per 100 parts by mass of the raw material monomer mixture. Examples of known chain transfer agents that can be used include carboxyl-containing mercaptans such as mercaptoacetic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, and mercaptosuccinic acid; alkyl mercaptans such as butanethiol, octanethiol, decanethiol, dodecanethiol, hexadecanethiol, and octadecanethiol; hydroxyl-containing mercaptans such as 2-mercaptoethanol and 3-mercapto-1,2-propanediol; and thiuram disulfides. One type of chain transfer agent may be used alone, or two or more types may be used in combination. The amount of the chain transfer agent added is preferably 0.1 to 20 parts by mass, more preferably 0.3 to 10 parts by mass, per 100 parts by mass of the raw material monomer mixture. There is no limitation on the chain form of the polymerized monomers, and any of the polymerization forms such as random, block, and graft may be used.

[0062] Preferred polymerization conditions vary depending on the types of polymerization initiator, monomer, and solvent used, but typically the polymerization temperature is preferably 30° C. or higher, more preferably 50° C. or higher, and preferably 95° C. or lower, more preferably 80° C. or lower. The polymerization time is preferably 1 hour or longer, more preferably 2 hours or longer, and preferably 20 hours or shorter, more preferably 10 hours or shorter. The polymerization atmosphere is preferably a nitrogen gas atmosphere or an inert gas atmosphere such as argon. After the polymerization reaction is completed, the produced polymer can be isolated from the reaction solution by a known method such as reprecipitation, solvent distillation, etc. The obtained polymer can also be purified by removing unreacted monomers and the like by reprecipitation, membrane separation, chromatography, extraction, etc.

[0063] When the hydrophilic monomer includes a monomer having an anionic group, the acid value of the water-soluble addition polymer F is, from the viewpoint of improving the dispersion stability of the crystalline polyester resin particles, preferably 50 mgKOH / g or more, more preferably 70 mgKOH / g or more, even more preferably 100 mgKOH / g or more, still more preferably 150 mgKOH / g or more, and is preferably 500 mgKOH / g or less, more preferably 450 mgKOH / g or less, even more preferably 400 mgKOH / g or less, and still more preferably 300 mgKOH / g or less. The acid value of the water-soluble addition polymer F can be measured by the method described in the Examples.

[0064] From the viewpoint of improving the dispersion stability of the crystalline polyester resin particles, the weight average molecular weight of the water-soluble addition polymer F is preferably 1,000 or more, more preferably 5,000 or more, even more preferably 9,000 or more, and is preferably 100,000 or less, more preferably 80,000 or less, even more preferably 60,000 or less. The weight average molecular weight can be measured by the method described in the Examples.

[0065] The amount of water-soluble addition polymer F added in step 1 is 0.2 parts by mass or more, preferably 0.4 parts by mass or more, more preferably 0.8 parts by mass or more, and even more preferably 2 parts by mass or more, per 100 parts by mass of resin in the resin particles, from the viewpoint of improving the dispersion stability of the crystalline polyester resin particles and from the viewpoint of improving the charge stability of the resulting toner, and is 30 parts by mass or less, more preferably 20 parts by mass or less, even more preferably 10 parts by mass or less, and even more preferably 5 parts by mass or less, from the viewpoint of suppressing a decrease in the charge amount of the toner under high temperature and high humidity conditions.

[0066] When the water-soluble addition polymer F has acid groups (e.g., -COOH, -SO3H, -OPO3H2), it is preferable that at least a portion of the acid groups be neutralized using a neutralizing agent in order to improve the dispersion stability of the crystalline polyester resin particles. Examples of the neutralizing agent include bases such as lithium hydroxide, sodium hydroxide, potassium hydroxide, ammonia, and various amines, with sodium hydroxide being preferred. The water-soluble addition polymer F may also be neutralized in advance. From the viewpoint of improving the dispersion stability of the crystalline polyester resin particles, the amount of the neutralizing agent used is preferably 10 mol% or more, more preferably 30 mol% or more, even more preferably 50 mol% or more, and even more preferably 70 mol% or more, and is 100 mol% or less. The equivalent amount of the neutralizing agent used can be calculated by the following formula: Equivalent amount of neutralizing agent used (mol%) = [{weight of neutralizing agent added (g) / equivalent amount of neutralizing agent} / [{acid value of water-soluble addition polymer F (mg KOH / g) × weight of water-soluble addition polymer F (g)} / (56 × 1,000)]] × 100

[0067] [Colorant particles] In step 1, it is preferable to aggregate colorant particles containing a colorant together with the resin particles. The colorant particles are preferably mixed with the resin particle dispersion described above as a colorant particle dispersion in which colorant particles containing a colorant are dispersed in an aqueous medium. As the colorant, any dye, pigment, etc. that is used as a colorant for toner can be used. Examples of colorants include carbon black, phthalocyanine blue (e.g., CI Pigment Blue 15:3), permanent brown FG, brilliant fast scarlet, pigment green B, rhodamine-B base, solvent red 49, solvent red 146, solvent blue 35, quinacridone, carmine 6B, and disazo yellow. The toner may be either black toner or a color toner other than black. From the viewpoint of image density, the content of the colorant in the toner particles is preferably 1% by mass or more, more preferably 2% by mass or more, even more preferably 3% by mass or more, and is preferably 25% by mass or less, more preferably 20% by mass or less, even more preferably 12% by mass or less.

[0068] [Method for producing colorant particle dispersion] The colorant particles are preferably obtained as a colorant particle dispersion by dispersing a colorant and an aqueous medium using a disperser such as a homogenizer, an ultrasonic disperser, etc. From the viewpoint of improving the dispersion stability of the colorant, the dispersion is preferably carried out in the presence of a surfactant or an addition polymer (hereinafter, the addition polymer used to disperse the colorant is also referred to as "addition polymer E"). Examples of surfactants include nonionic surfactants, anionic surfactants, and cationic surfactants. The addition polymer E preferably has a constituent unit derived from an addition polymerizable monomer a having an aromatic group, and preferably further contains at least one selected from the group consisting of an addition polymerizable monomer b having an ionic group, an addition polymerizable monomer c having a polyalkylene oxide group, and a macromonomer d. For details of a colorant particle dispersion using the addition polymer E, see JP 2021-26129 A.

[0069] From the viewpoint of image density of printed matter, the content of the colorant in the colorant particle dispersion is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, and is preferably 40% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less. The solid content of the colorant particle dispersion is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, and is preferably 40% by mass or less, and more preferably 30% by mass or less.

[0070] Volume median particle size D of colorant particles 50 From the viewpoint of improving the dispersibility of the colorant in the toner, the particle size is preferably 0.05 μm or more, more preferably 0.08 μm or more, and is preferably 0.4 μm or less, more preferably 0.3 μm or less, and even more preferably 0.25 μm or less. From the viewpoint of improving the dispersibility of the colorant in the toner, the CV value of the colorant particles is preferably 10% or more, more preferably 15% or more, and is preferably 40% or less, more preferably 35% or less, and even more preferably 30% or less. Volume median particle size D of colorant particles 50 and CV values ​​are measured by the methods in the Examples.

[0071] [Release agent particles] In step 1, it is preferable to aggregate release agent particles containing a release agent together with the resin particles and colorant particles. The release agent particles are preferably mixed with the resin particle dispersion described above as a release agent particle dispersion in which release agent particles containing a release agent are dispersed in an aqueous medium. Examples of release agents include polypropylene wax, polyethylene wax, ethylene-propylene copolymer wax; hydrocarbon waxes such as microcrystalline wax, paraffin wax, and Fischer-Tropsch wax, or oxides thereof; ester waxes such as carnauba wax, montan wax, or deacidified waxes thereof, and fatty acid ester wax; fatty acid amides, fatty acids, higher alcohols, and fatty acid metal salts. These may be used alone or in combination.

[0072] The melting point of the release agent is preferably 60°C or higher, more preferably 70°C or higher, and preferably 160°C or lower, more preferably 140°C or lower, even more preferably 120°C or lower, and even more preferably 100°C or lower.

[0073] The content of the release agent in the toner particles is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 5% by mass or more, and preferably 25% by mass or less, more preferably 20% by mass or less, even more preferably 16% by mass or less.

[0074] [Method for producing release agent particle dispersion] The release agent particle dispersion can be obtained using a surfactant, but is preferably obtained by mixing the release agent and resin particles. By preparing the release agent particles using the release agent and resin particles, the release agent particles are stabilized by the resin that constitutes the resin particles, and it becomes possible to disperse the release agent in an aqueous medium without using a surfactant. It is believed that the release agent particle dispersion has a structure in which a large number of resin particles adhere to the surfaces of the release agent particles. The resin constituting the resin particles in which the release agent is dispersed is preferably a polyester resin, and the above-mentioned amorphous polyester resin is more preferable. Also, a composite resin having a polyester resin segment and an addition polymerization resin segment may be used. For the composite resin, see JP 2021-182045 A.

[0075] Volume median particle size D of release agent particles 50 From the viewpoint of obtaining uniform aggregated particles 1 by aggregation, the average particle size is preferably 0.05 μm or more, more preferably 0.1 μm or more, even more preferably 0.2 μm or more, and is preferably 1 μm or less, more preferably 0.8 μm or less, even more preferably 0.6 μm or less. The CV value of the release agent particles is preferably 10% or more, more preferably 15% or more, and is preferably 45% or less, more preferably 40% or less. The volume median particle diameter D50 and CV value of the release agent particles are measured by the method described in the examples.

[0076] The aggregated particles 1 may also contain additives such as charge control agents, magnetic powders, flowability improvers, conductivity adjusters, reinforcing fillers such as fibrous substances, antioxidants, antiaging agents, and cleaning property improvers.

[0077] [Surfactant] In step 1, the resin particles are preferably aggregated after preparing a mixed dispersion by mixing a resin particle dispersion with, if necessary, a colorant particle dispersion and a release agent particle dispersion. The mixed dispersion may be prepared in the presence of a surfactant in order to improve the dispersion stability of the resin particles and optional components, such as colorant particles and release agent particles, which are added as needed. Examples of the surfactant include anionic surfactants such as alkylbenzene sulfonates and alkyl ether sulfates; and nonionic surfactants such as polyoxyethylene alkyl ethers and polyoxyethylene alkenyl ethers. One or more surfactants may be used. When a surfactant is used, the amount used is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and preferably 10 parts by mass or less, more preferably 5 parts by mass or less, per 100 parts by mass of resin particles as the total amount of surfactant.

[0078] The resin particle dispersion and the optional components are mixed by a conventional method. From the viewpoint of efficiently flocculating the particles, it is preferable to add a flocculating agent to the mixed dispersion obtained by the mixing.

[0079] [Flocculant] Examples of the flocculant include organic flocculants such as quaternary salt cationic surfactants and polyethyleneimine; inorganic metal salts such as sodium sulfate, sodium nitrate, sodium chloride, calcium chloride, and calcium nitrate; inorganic ammonium salts such as ammonium sulfate, ammonium chloride, and ammonium nitrate; and inorganic flocculants such as divalent or higher metal complexes. From the viewpoint of improving the flocculation properties and obtaining uniform flocculated particles 1, inorganic flocculants having a valence of 1 to 5 are preferred, inorganic metal salts having a valence of 1 to 2 and inorganic ammonium salts are more preferred, and ammonium sulfate is even more preferred.

[0080] For example, an aggregating agent is added in an amount of 5 to 50 parts by mass relative to 100 parts by mass of resin particles to a mixed dispersion liquid containing resin particles, release agent particles, and colorant particles and having a temperature of 0 to 40°C, and the resin particles, release agent particles, and colorant particles are aggregated in an aqueous medium to obtain aggregated particles 1. Furthermore, from the viewpoint of promoting aggregation, it is preferable to increase the temperature of the dispersion liquid after adding the aggregating agent.

[0081] Volume median particle size D of aggregated particles 1 obtained in step 1 50 is preferably 3 μm or more, more preferably 4 μm or more, even more preferably 5 μm or more, and is preferably 10 μm or less, more preferably 8 μm or less, even more preferably 7 μm or less. It is preferable to continue the aggregation until a desired volume median particle size is reached to obtain aggregated particles 1.

[0082] In the production method of the present invention, in order to obtain toner particles having a core-shell structure, in step 1, the obtained aggregated particles 1 may be used as cores, and shell resin particles containing an amorphous resin may be attached and aggregated to obtain aggregated particles 2 having a core-shell structure. As the shell resin particles, amorphous resin A can be preferably used. The shell resin particle dispersion liquid can be obtained by the same method as the above-mentioned method for producing the resin particle dispersion liquid. Furthermore, when the shell resin particles are aggregated in step 1 of the production method of the present invention, it is preferable to proceed to step 2 after the aggregated particles 2 have grown to a particle size appropriate for toner particles. From the viewpoint of low-temperature fixability of the toner, the mass ratio of the shell resin particles to the mass of the aggregated particles 1 [shell resin particles / aggregated particles 1] is preferably 1 / 99 or more, more preferably 3 / 97 or more, even more preferably 5 / 95 or more, and is preferably 20 / 80 or less, more preferably 15 / 85 or less, even more preferably 10 / 90 or less.

[0083] <Process 2> Step 2 is a step of fusing the aggregated particles obtained in Step 1 to obtain fused particles. In Step 2, the particles in the aggregated particles, which were primarily physically adhered to each other, are fused together to form toner particles.

[0084] In step 2, the temperature at which the aggregated particles are maintained during fusion is, from the viewpoint of improving the fusion properties of the aggregated particles, preferably at least 20°C lower, more preferably at least 15°C lower, than the melting point of the crystalline polyester resin, and preferably not more than 1°C lower, more preferably not more than 5°C lower, than the melting point of the crystalline polyester resin. Furthermore, in step 2, when the aggregated particles contain amorphous resin A, the holding temperature during fusion of the aggregated particles is preferably equal to or higher than the glass transition temperature of amorphous resin A. From the viewpoint of improving the fusion properties of the aggregated particles and improving the productivity of the toner, the holding temperature in the fusion step is preferably equal to or higher than the glass transition temperature of amorphous resin A by 2°C or more, more preferably equal to or higher than the glass transition temperature of amorphous resin A by 5°C or more, and is preferably equal to or lower than the glass transition temperature of amorphous resin A by 30°C or more, more preferably equal to or lower than the glass transition temperature of amorphous resin A by 20°C or less, from the viewpoint of improving the fusion properties of the aggregated particles and improving the productivity of the toner. In this case, the time for which the above-mentioned holding temperature is maintained is preferably 1 minute or more, more preferably 10 minutes or more, and even more preferably 30 minutes or more, from the viewpoint of promoting fusion of the aggregated particles and obtaining the desired circularity, and is preferably 240 minutes or less, more preferably 180 minutes or less, even more preferably 120 minutes or less, and even more preferably 90 minutes or less, from the viewpoint of productivity. It is preferable to maintain the temperature at the above temperature until the desired circularity is achieved.

[0085] The volume median particle size (D 50 From the viewpoint of versatility of the toner, the particle size is preferably 3 μm or more, more preferably 4 μm or more, even more preferably 5 μm or more, and is preferably 10 μm or less, more preferably 8 μm or less, even more preferably 7 μm or less. The volume median particle size of the fused particles obtained in step 2 is preferably equal to or smaller than the volume median particle size of the aggregated particles. That is, in step 2, it is preferable that aggregation and fusion between the aggregated particles do not occur.

[0086] <Post-processing process> In the production method of the present invention, a post-treatment step may be carried out after step 2, and it is preferable to obtain toner particles by isolation. Since the fused particles obtained in step 2 are present in an aqueous medium, it is preferable to first carry out solid-liquid separation, which is preferably carried out by suction filtration or the like. It is preferable to wash the solid-liquid separation product. At this time, it is preferable to remove the added surfactant and the like. Therefore, if the surfactant has a cloud point, washing with an aqueous medium at a temperature below the cloud point of the surfactant is preferable. It is preferable to wash the solid-liquid separation product multiple times.

[0087] Next, it is preferable to carry out drying. The temperature during drying is preferably set so that the temperature of the fused particles themselves is lower than the glass transition temperature of the amorphous resin A, and more preferably 10°C or more lower. As the drying method, it is preferable to use a vacuum constant temperature drying method, a vibration fluidized bed drying method, a spray drying method, a freeze drying method, a flash jet method, or the like.

[0088] [Toner particles] The toner particles obtained by drying or the like can be used as they are as a toner for developing electrostatic images, but it is preferable to use toner particles whose surfaces have been treated as described below as a toner for developing electrostatic images. The volume median particle size of the toner particles (D 50 ) is preferably 2 μm or more, more preferably 3 μm or more, even more preferably 4 μm or more, and is preferably 10 μm or less, more preferably 8 μm or less, even more preferably 7 μm or less. The CV value of the toner particles is preferably 12% or more, more preferably 14% or more, and even more preferably 16% or more, from the viewpoint of improving toner productivity, and is preferably 40% or less, more preferably 35% or less, from the viewpoint of obtaining high-quality images. From the viewpoint of obtaining high-quality images, the circularity of the toner particles is preferably 0.950 or more, more preferably 0.955 or more, even more preferably 0.960 or more, and is preferably 0.990 or less, more preferably 0.985 or less, even more preferably 0.980 or less.

[0089] <External additives> The toner particles can be used as they are, but it is preferable to use the toner after adding a fluidizing agent or the like as an external additive to the surface of the toner particles. Examples of external additives 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, and among these, hydrophobic silica is preferred. The external additives may be used alone or in combination of two or more. Also, external additives of the same type but different particle diameters may be used in combination. When the surface treatment of the toner particles is performed using an external additive, the amount of the external additive added is preferably 1 part by mass or more, more preferably 2 parts by mass or more, even more preferably 3 parts by mass or more, and preferably 5 parts by mass or less, more preferably 4.5 parts by mass or less, even more preferably 4 parts by mass or less, relative to 100 parts by mass of the toner particles.

[0090] [Electrostatic image developing toner] The toner for developing electrostatic images obtained by the present invention can be used as a one-component developer, or mixed with a carrier to form a two-component developer. [Example]

[0091] The present invention will be described in more detail below with reference to examples, etc. In the following examples, the measurement and evaluation of various physical properties were carried out by the following methods.

[0092] [measurement] [Softening point, crystallinity index, melting point and glass transition temperature of resin] (1) Softening point Using a flow tester "CFT-500D" (Shimadzu Corporation), 1 g of sample was heated at a temperature increase rate of 6°C / min, while a load of 1.96 MPa was applied by the plunger, and the sample was extruded from a nozzle 1 mm in diameter and 1 mm in length. The plunger depression distance 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) Crystallinity index Using a differential scanning calorimeter "Q100" (TA Instruments Japan), 0.02 g of sample was weighed into an aluminum pan and cooled to 0°C at a rate of 10°C / min. The sample was then left to stand for 1 minute, after which it was heated to 180°C at a rate of 10°C / min and the calorific value was measured. The temperature of the peak with the largest area among the observed endothermic peaks was taken as the endothermic maximum peak temperature, and the crystallinity index was calculated by dividing the endothermic maximum peak temperature by the formula: (softening point (°C)) / (endothermic maximum peak temperature (°C)). (3) Melting point and glass transition temperature Using a differential scanning calorimeter "Q100" (manufactured by TA Instruments Japan Co., Ltd.), 0.02 g of sample was weighed into an aluminum pan, heated to 200°C, and cooled to 0°C at a rate of 10°C / min. The sample was then heated at a rate of 10°C / min, and the calorific value was measured. The temperature of the peak with the largest peak area among the observed endothermic peaks was taken as the maximum endothermic peak temperature (2). For crystalline resins, this peak temperature was taken as the melting point. In the case of an amorphous resin, when a peak is observed, the temperature of the peak is taken as the glass transition temperature. When a step is observed instead of a peak, the temperature at the intersection of the tangent line showing the maximum slope of the curve at the step and an extension of the baseline on the low-temperature side of the step is taken as the glass transition temperature.

[0093] [Acid value of resin and water-soluble addition polymer F] Measurement was carried out according to the neutralization titration method described in JIS K 0070:1992, except that the measurement solvent was chloroform.

[0094] [Weight average molecular weight (Mw) of water-soluble addition polymer F] The measurements were performed using gel permeation chromatography (GPC) on a Tosoh GPC system (HLC-8320GPC) with Tosoh columns (TSKgel SuperAWM-H, TSKgel SuperAW3000, TSKgel guardcolumn Super AW-H) at a flow rate of 0.5 mL / min, using N,N-dimethylformamide containing phosphate and lithium bromide at concentrations of 43 mmol / L and 50 mmol / L, respectively, as the eluent. The measurements were performed using a monodisperse polystyrene kit (PStQuick B (F-550, F-80, F-10, F-1, A-1000) and PStQuick C (F-288, F-40, F-4, A-5000, A-500), both manufactured by Tosoh) with known molecular weights as standards. The measurement sample was prepared by mixing 0.1 g of polymer with 10 mL of the eluent in a glass vial, stirring with a magnetic stirrer at 25° C. for 10 hours, and filtering with a syringe filter (DISMIC-13HP PTFE 0.2 μm, manufactured by ADVANTEC).

[0095] [Melting point of release agent] Using a differential scanning calorimeter "Q100" (TA Instruments Japan Co., Ltd.), 0.02 g of sample was weighed into an aluminum pan, heated to 200°C, and then cooled from 200°C to 0°C at a rate of 10°C / min. The sample was then heated at a rate of 10°C / min, the calorific value was measured, and the maximum endothermic peak temperature was taken as the melting point.

[0096] [Volume median particle diameter D of resin particles, colorant particles, and release agent particles 50 and CV value) (1) Measuring device: Laser diffraction particle size measuring instrument "LA-920" (manufactured by Horiba Ltd.) (2) Measurement conditions: Put the sample dispersion in a measurement cell, add distilled water, and measure the volume median particle size D at a concentration where the absorbance is in the appropriate range. 50 and volume average particle size D V The CV value was calculated according to the following formula: CV value (%) = (standard deviation of particle size distribution) / volume average particle size D V ) x 100

[0097] [Solid Content Concentration of Resin Particle Dispersion, Colorant Particle Dispersion, and Release Agent Particle Dispersion] Using an infrared moisture meter "FD-230" (Kett Electric Laboratory Co., Ltd.), the moisture content (mass%) of 5 g of the measurement sample was measured at a drying temperature of 150°C and measurement mode 96 (monitoring time 2.5 minutes, moisture content fluctuation range 0.05%). The solid content concentration was calculated according to the following formula. Solid concentration (mass%) = 100-moisture (mass%)

[0098] [Volume median particle size of agglomerated particles D 50 〕 Measuring instrument: "Coulter Multisizer (registered trademark) III" (manufactured by Beckman Coulter, Inc.) Aperture diameter: 50 μm Analysis software: "Multisizer (registered trademark) III version 3.51" (Beckman Coulter, Inc.) Electrolyte: "Isoton (registered trademark) II" (manufactured by Beckman Coulter, Inc.) Measurement conditions: The sample dispersion is added to 100 mL of the electrolyte to adjust the concentration so that the particle size of 30,000 particles can be measured in 20 seconds. Then, 30,000 particles are measured again, and the volume median particle size D is calculated from the particle size distribution. 50 asked for.

[0099] [Circularity of fused particles] Measurement equipment: Flow particle image analyzer "FPIA-3000" (Sysmex Corporation) Preparation of dispersion: The dispersion of fused particles was diluted with deionized water to a solids concentration of 0.001 to 0.05% by mass. Measurement mode: HPF measurement mode

[0100] [Volume median particle size D of toner particles 50 and CV value) The measurement device, aperture diameter, analysis software, and electrolyte were determined based on the volume median particle diameter D 50 The same material as that used in the measurement was used. Dispersion: Polyoxyethylene lauryl ether "EMULGEN (registered trademark) 109P" (manufactured by Kao Corporation, HLB (Hydrophile-Lipophile Balance) = 13.6) was dissolved in the electrolyte solution to obtain a dispersion with a concentration of 5 mass %. Dispersion conditions: 10 mg of a measurement sample of dried toner particles was added to 5 mL of the dispersion liquid, and the mixture was dispersed for 1 minute using an ultrasonic disperser. Thereafter, 25 mL of the electrolyte solution was added, and the mixture was further dispersed for 1 minute using the ultrasonic disperser to prepare a sample dispersion liquid. Measurement conditions: The sample dispersion is added to 100 mL of the electrolyte to adjust the concentration so that the particle size of 30,000 particles can be measured in 20 seconds. Then, 30,000 particles are measured and the volume median particle size D is calculated from the particle size distribution. 50 and volume average particle size D V asked for. The CV value (%) was calculated according to the following formula: CV value (%) = (standard deviation of particle size distribution) / volume average particle size D V ) x 100

[0101] [Resin manufacturing] (Production of crystalline polyester resin) Manufacturing Example C1 (Manufacturing of Resin C-1) A 10-liter four-neck flask equipped with a nitrogen inlet tube, dehydration tube, stirrer, and thermocouple was purged with nitrogen. The raw material monomers for the polyester resin shown in Table 1 were added, and the reaction system was heated to 135°C while stirring. After maintaining this temperature for 3 hours, the temperature was increased from 135°C to 200°C over 10 hours. 23 g of tin(II) di(2-ethylhexanoate) was then added to the reaction system, and the temperature was maintained at 200°C for another hour. The pressure inside the flask was then reduced, and the reaction was continued at 8 kPa until the softening point shown in Table 1 was reached, yielding Resin C-1. The physical properties are shown in Table 1.

[0102] Manufacturing Example C2 (Manufacturing of Resin C-2) Resin C-2 was obtained in the same manner as in Production Example C1, except that the types and amounts of raw material monomers for the polyester resin were changed as shown in Table 1. The physical property values ​​are shown in Table 1.

[0103] [Table 1]

[0104] (Production of amorphous polyester resin) Production Example A1 (Production of Resin A-1) A 10-L four-neck flask equipped with a thermometer, stainless steel stirrer, dehydration tube, condenser, and nitrogen inlet tube was charged with neopentyl glycol, terephthalic acid, and the esterification catalyst shown in Table 2. The mixture was heated to 180°C in a nitrogen atmosphere in a mantle heater. After two hours of reaction, the mixture was heated to 210°C at a rate of 5°C / h. After cooling to 180°C, the isophthalic acid shown in Table 2 was added. The mixture was heated again to 190°C and reacted for one hour. The mixture was then heated to 220°C at a rate of 10°C / h. The reaction was continued at 13.3 kPa until the softening point shown in Table 2 was reached, yielding Resin A-1. The physical properties are shown in Table 2.

[0105] Production Example A2 (Production of Resin A-2) A 10L four-neck flask equipped with a nitrogen inlet tube, dehydration tube, stirrer, and thermocouple was charged with the raw material monomers for the polyester resin (except trimellitic anhydride) shown in Table 2, and the esterification catalyst. Under a nitrogen atmosphere, the mixture was heated to 235°C with stirring. After holding at 235°C for 6 hours, the pressure in the flask was further reduced to 8.3 kPa and held for 1 hour. The mixture was then cooled to 215°C and returned to atmospheric pressure. The trimellitic anhydride shown in Table 2 was added, and the mixture was held at 215°C for 1 hour. The pressure in the flask was further reduced to 8.3 kPa and the reaction proceeded until the softening point shown in Table 2 was reached, yielding Resin A-2. The physical properties are shown in Table 2.

[0106] [Table 2]

[0107] [Production of resin particle dispersion] Production Example X1 (Production of Resin Particle Dispersion X-1) 1000 g of Resin A-1 and 1000 g of methyl ethyl ketone were placed in a 5 L vessel equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen inlet tube, and the resin was dissolved over 1 hour at 80° C. A 5% by mass aqueous solution of sodium hydroxide was added to the resulting solution so that the degree of neutralization relative to the acid value of the resin was 80 mol%, and the mixture was stirred for 30 minutes. Next, while maintaining the temperature at 80°C, 2700 g of deionized water was added over 60 minutes while stirring at 280 r / min (circumferential speed 88 m / min) to cause phase inversion emulsification. While continuing to maintain the temperature at 80°C, methyl ethyl ketone was distilled off under reduced pressure to obtain an aqueous dispersion. Thereafter, while continuing to stir at 280 r / min (circumferential speed 88 m / min), the aqueous dispersion was cooled to 30°C, and deionized water was added to obtain a solids concentration of 25 mass%, thereby obtaining resin particle dispersion X-1. The volume median particle diameter D of the resulting resin particles was 50 and CV values ​​are shown in Table 3.

[0108] Production Examples X2, Y1, and Y2 (Production of Resin Particle Dispersions X-2, Y-1, and Y-2) Resin particle dispersions X-2, Y-1, and Y-2 were obtained in the same manner as in Production Example X1, except that the resin used was changed to that shown in Table 3. The volume median particle diameter D of the obtained resin particles 50 and CV values ​​are shown in Table 3.

[0109] Production Example Z1 (Production of Resin Particle Dispersion Z-1) 800 g of Resin A-1, 200 g of Resin C-1, and 1000 g of methyl ethyl ketone were placed in a 5 L vessel equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen inlet tube, and the resins were dissolved over 1 hour at 80° C. A 5% by mass aqueous solution of sodium hydroxide was added to the resulting solution so that the degree of neutralization relative to the acid value of the resin was 80 mol%, and the mixture was stirred for 30 minutes. Next, while maintaining the temperature at 80°C, 2700 g of deionized water was added over 60 minutes while stirring at 280 r / min (circumferential speed 88 m / min), resulting in phase inversion emulsification. While continuing to maintain the temperature at 80°C, methyl ethyl ketone was distilled off under reduced pressure to obtain an aqueous dispersion. Thereafter, while continuing to stir at 280 r / min (circumferential speed 88 m / min), the aqueous dispersion was cooled to 30°C, and deionized water was added to obtain a solids concentration of 25% by mass, thereby obtaining resin particle dispersion Z-1. The volume median particle diameter D of the resulting resin particles was 50 and CV values ​​are shown in Table 3.

[0110] Production Example P1 (Production of Resin Particle Dispersion P-1) 200 g of Resin A-1 and 200 g of methyl ethyl ketone were placed in a 3 L vessel equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen inlet tube, and the resin was dissolved at 80°C for 1 hour. A 5% by mass aqueous solution of sodium hydroxide was added to the resulting solution to achieve a neutralization degree of 75 mol% relative to the acid value of Resin A-1, and the mixture was stirred for 30 minutes. Next, while maintaining the temperature at 80°C, 700 g of deionized water was added over 50 minutes while stirring at 280 r / min (circumferential speed 88 m / min) to cause phase inversion emulsification. While continuing to maintain the temperature at 80°C, the methyl ethyl ketone was distilled off under reduced pressure to obtain an aqueous dispersion. The aqueous dispersion was then cooled to 30°C while stirring at 280 r / min (circumferential speed 88 m / min), and deionized water was added to obtain a solids concentration of 20% by mass, yielding Resin Particle Dispersion P-1. The volume median particle diameter D of the resulting resin particles was 0.01 g. 50 and CV values ​​are shown in Table 3.

[0111] [Table 3]

[0112] [Production of Water-Soluble Addition Polymer F] Production Example F1 (Production of Water-Soluble Addition Polymer F-1) A raw material monomer mixture was prepared by mixing 31 parts by mass of acrylic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 59 parts by mass of styrene (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and 10 parts by mass of α-methylstyrene (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.). 10 parts by mass of methyl ethyl ketone, 0.3 parts by mass of 2-mercaptopropionic acid (a polymerization chain transfer agent), and 10% by mass of the raw material monomer mixture were placed in a reaction vessel and mixed, and the atmosphere was thoroughly purged with nitrogen gas. Separately, a mixture of the remaining raw monomer mixture, 0.27 parts by weight of the polymerization chain transfer agent, 40 parts by weight of methyl ethyl ketone, and 1.25 parts by weight of an azo-based radical polymerization initiator (V-501; 4,4'-azobis(4-cyanovaleric acid) manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was placed in a dropping funnel. Under a nitrogen atmosphere, the monomer mixture in the reaction vessel was heated to 65°C with stirring, and the mixture in the dropping funnel was added dropwise over 3 hours. After 2 hours at 65°C after the completion of the dropping, a solution of 0.15 parts by weight of the polymerization initiator in 2.5 parts by weight of methyl ethyl ketone was added. The mixture was further aged at 65°C for 2 hours and then at 70°C for 2 hours, followed by drying under reduced pressure to obtain a water-soluble addition polymer F-1 having a carboxy group. The acid value and weight-average molecular weight of the resulting water-soluble addition polymer are shown in Table 4.

[0113] Production Example F2 (Production of Water-Soluble Addition Polymer F-2) A water-soluble addition polymer F-2 having a carboxy group was obtained in the same manner as in Production Example F1, except that the raw material monomers, polymerization chain transfer agent, and polymerization initiator shown in Table 4 were used in the amounts (parts by mass) shown in Table 4. The polymerization chain transfer agent was placed in an amount of 0.41 parts by mass in the reaction vessel and 0.37 parts by mass in the dropping funnel. The acid value and weight-average molecular weight of the resulting water-soluble addition polymer are shown in Table 4.

[0114] Production Example F3 (Production of Water-Soluble Addition Polymer F-3) A water-soluble addition polymer F-3 having a carboxy group was obtained in the same manner as in Production Example F1, except that the raw material monomers, polymerization chain transfer agent, and polymerization initiator shown in Table 4 were used in the amounts (parts by mass) shown in Table 4. The polymerization chain transfer agent was placed in an amount of 0.6 part by mass in the reaction vessel and 0.5 part by mass in the dropping funnel. The acid value and weight-average molecular weight of the obtained water-soluble addition polymer are shown in Table 4.

[0115] Production Example F4 (Production of Water-Soluble Addition Polymer F-4) A water-soluble addition polymer F-4 having a carboxy group was obtained in the same manner as in Production Example F1, except that the raw material monomers, polymerization chain transfer agent, and polymerization initiator shown in Table 4 were used in the amounts (parts by mass) shown in Table 4. The polymerization chain transfer agent was placed in an amount of 3.0 parts by mass in the reaction vessel and 2.7 parts by mass in the dropping funnel. The acid value and weight-average molecular weight of the resulting water-soluble addition polymer F are shown in Table 4.

[0116] [Table 4]

[0117] Production Example G1 (Production of Aqueous Solution G-1 of Water-Soluble Addition Polymer F-1) A 2 L vessel equipped with a stirrer, reflux condenser, thermometer, and nitrogen inlet tube was charged with 200 g of water-soluble addition polymer F-1, 450 g of deionized water, and a 5% by mass aqueous solution of sodium hydroxide to a degree of neutralization of 100 mol% relative to the acid value of water-soluble addition polymer F-1. The resin was dissolved in water over 3 hours at 80°C while stirring at 280 r / min (peripheral speed 88 m / min). After cooling to 30°C, deionized water was added to a solids concentration of 15% by mass, yielding an aqueous solution G-1 of water-soluble addition polymer F-1.

[0118] Production Example G2 (Production of Aqueous Solution G-2 of Water-Soluble Addition Polymer F-2) An aqueous solution G-2 of the water-soluble addition polymer F-2 (solid concentration 15% by mass) was obtained in the same manner as in Production Example G1, except that 200 g of the water-soluble addition polymer F-2, 800 g of deionized water, and a 5% by mass aqueous solution of sodium hydroxide were placed in a 2 L container so that the degree of neutralization was 100 mol% relative to the acid value of the water-soluble addition polymer F-2.

[0119] Production Example G3 (Production of Aqueous Solution G-3 of Water-Soluble Addition Polymer F-3) An aqueous solution G-3 of the water-soluble addition polymer F-3 (solid concentration 15% by mass) was obtained in the same manner as in Production Example G1, except that 200 g of the water-soluble addition polymer F-3, 500 g of deionized water, and a 5% by mass aqueous solution of sodium hydroxide were placed in a 2 L container so that the degree of neutralization was 100 mol% relative to the acid value of the water-soluble addition polymer F-3.

[0120] Production Example G4 (Production of Aqueous Solution G-4 of Water-Soluble Addition Polymer F-4) An aqueous solution G-4 of the water-soluble addition polymer F-4 (solid concentration 15% by mass) was obtained in the same manner as in Production Example G1, except that 200 g of the water-soluble addition polymer F-4, 500 g of deionized water, and a 5% by mass aqueous solution of sodium hydroxide were placed in a 2 L container so that the degree of neutralization was 100 mol% relative to the acid value of the water-soluble addition polymer F-4.

[0121] (Production of release agent particle dispersion) Production Example W1 (Production of Release Agent Particle Dispersion W-1) 25 g of deionized water, 120 g of resin particle dispersion P-1, and 60 g of paraffin wax "HNP-9" (manufactured by Nippon Seiro Co., Ltd., melting point 75°C) were added to a 1 L beaker, and the mixture was melted and stirred while maintaining the temperature at 90-95°C to obtain a molten mixture. The obtained molten mixture was dispersed for 20 minutes using an ultrasonic homogenizer "US-600T" (manufactured by Nippon Seiki Seisakusho Co., Ltd.) while maintaining the temperature at 90 to 95°C, and then cooled to room temperature (20°C). Deionized water was added to the obtained dispersion to adjust the solid content to 40% by mass, thereby obtaining release agent particle dispersion W-1. The volume median particle diameter D of the release agent particles in release agent particle dispersion W-1 was 50 The particle size was 0.29 μm and the CV value was 37%.

[0122] Production Example W2 (Production of Release Agent Particle Dispersion W-2) Release agent particle dispersion W-2 was obtained in the same manner as in Production Example W1, except that the type of release agent was changed to Fischer-Tropsch wax "FNP-0090" (manufactured by Nippon Seiro Co., Ltd., melting point 90°C).50 The particle size was 0.26 μm and the CV value was 39%.

[0123] (Production of Colorant Particle Dispersion) Production Example E1 (Production of Colorant Particle Dispersion E-1) In a 1 L beaker, 100 g of Pigment Blue 15:3 (Dainichiseika Color & Chemicals Mfg. Co., Ltd., "ECB301," molecular weight 576), 167 g of 15 wt. % sodium dodecylbenzenesulfonate aqueous solution "Neopelex G-15" (Kao Corporation, anionic surfactant), and 102 g of deionized water were mixed and dispersed at 20°C for 1 hour using a homomixer "TKAGI HOMOMIXER 2M-03" (Primix Corporation) at a stirring blade rotation speed of 8000 r / min. The mixture was then passed through a homogenizer "Microfluidizer M-110EH" (Microfluidics) at 150 MPa for 15 passes. The mixture was then passed through a 200-mesh filter, and deionized water was added to obtain a solids concentration of 20 wt. Colorant particle dispersion E-1 was obtained. The volume median particle diameter D of the resulting colorant particles was 1.0 μm. 50 The particle size was 0.12 μm and the CV value was 22%.

[0124] Example 1 (Production of Toner 1) A 3-L four-neck flask equipped with a dehydration tube, a stirrer, and a thermocouple was charged with 640 g of resin particle dispersion X-1, 160 g of resin particle dispersion Y-1, 52 g of release agent particle dispersion W-1, 52 g of release agent particle dispersion W-2, 101 g of colorant particle dispersion E-1, and 180 g of deionized water, and mixed. Next, while stirring the mixture at 25°C, 40 g of aqueous solution G-1 of water-soluble addition polymer F-1 was added, and a solution prepared by dissolving 51 g of ammonium sulfate in 866 g of deionized water and adding a 4.8% by mass aqueous potassium hydroxide solution to adjust the pH to 8.0 was added dropwise at 25°C over 60 minutes, and the temperature was then raised to 55°C over 1 hour. The volume median particle diameter D of the aggregated particles was then measured. 50 The temperature was maintained at 55°C until the particle size reached 6.0 µm, thereby obtaining a dispersion of aggregated particles. To the resulting dispersion of aggregated particles, 61 g of an aqueous solution of β-naphthalenesulfonic acid formalin condensate sodium salt "Demol N" (manufactured by Kao Corporation) with a solids concentration of 20 mass % and 223 g of deionized water were mixed and added. Then, 170 g of a 4.8 mass % aqueous potassium hydroxide solution was added dropwise over 10 minutes. The temperature was then raised to 70°C over 1 hour and maintained at 70°C until the circularity reached 0.970, thereby obtaining a dispersion of fused particles in which the aggregated particles were fused together. The resulting fused particle dispersion was cooled to 30°C, filtered under suction to separate the solids, washed with deionized water at 25°C, and filtered under suction for 2 hours at 25°C. The solids were then vacuum dried at 33°C for 24 hours using a vacuum constant temperature dryer "DRV622DA" (manufactured by ADVANTEC) to obtain toner particles. 100 parts by weight of the toner particles, 2.5 parts by weight of hydrophobic silica "RY50" (manufactured by Nippon Aerosil Co., Ltd., number average particle size; 0.04 μm), and 1.0 part by weight of hydrophobic silica "Cabosil® TS720" (manufactured by Cabot Japan Co., Ltd., number average particle size; 0.012 μm) were mixed in a Henschel mixer and passed through a 150-mesh sieve to obtain Toner 1. The physical properties of the resulting toner particles and the evaluation results of the toner are shown in Table 5.

[0125] Examples 2 to 4 (Production of Toners 2 to 4) Toners 2 to 4 were produced in the same manner as in Example 1, except that the type of aqueous solution of water-soluble addition polymer F used was changed as shown in Table 5. Table 5 shows the physical property values ​​of the obtained toner particles and the evaluation results of the toner.

[0126] Examples 5 to 7 (Production of Toners 5 to 7) Toners 5 to 7 were produced in the same manner as in Example 1, except that the type of resin particle dispersion used was changed as shown in Table 5. Table 5 shows the physical property values ​​of the obtained toner particles and the evaluation results of the toner.

[0127] Example 8 (Production of Toner 8) Toner 8 was produced in the same manner as in Example 1, except that the resin particle dispersion used was changed to 800 g of Resin Particle Dispersion Z-1. Table 5 shows the physical property values ​​of the obtained toner particles and the evaluation results of the toner.

[0128] Example 9 (Production of Toner 9) A 3-L four-neck flask equipped with a dehydration tube, a stirrer, and a thermocouple was charged with 640 g of resin particle dispersion X-1, 160 g of resin particle dispersion Y-1, 52 g of release agent particle dispersion W-1, 52 g of release agent particle dispersion W-2, 101 g of colorant particle dispersion E-1, 40 g of aqueous solution G-1 of water-soluble addition polymer F-1, and 180 g of deionized water, and mixed. Next, while stirring the mixture at 25°C, a solution prepared by dissolving 51 g of ammonium sulfate in 866 g of deionized water and adding a 4.8 mass% potassium hydroxide aqueous solution to adjust the pH to 8.0 was added dropwise over 60 minutes at 25°C, and the temperature was then raised to 55°C over 1 hour, and the volume median particle diameter D of the aggregated particles was measured. 50 The temperature was maintained at 55°C until the particle size reached 6.0 µm, thereby obtaining a dispersion of aggregated particles. Thereafter, toner 9 was produced in the same manner as in Example 1. Table 5 shows the physical property values ​​of the obtained toner particles and the evaluation results of the toner.

[0129] Example 10 (Production of Toner 10) A 3-L four-neck flask equipped with a dehydration tube, a stirrer, and a thermocouple was charged with 640 g of resin particle dispersion X-1, 160 g of resin particle dispersion Y-1, 52 g of release agent particle dispersion W-1, 52 g of release agent particle dispersion W-2, 101 g of colorant particle dispersion E-1, and 208 g of deionized water, and mixed. Next, while stirring the mixture at 25°C, 6.7 g of aqueous solution G-1 of water-soluble addition polymer F-1 was added, and a solution prepared by dissolving 51 g of ammonium sulfate in 866 g of deionized water and adding a 4.8% by mass aqueous potassium hydroxide solution to adjust the pH to 8.0 was added dropwise over 60 minutes at 25°C, and the mixture was then heated to 55°C over 1 hour, and the volume median particle diameter D of the aggregated particles was measured. 50 The temperature was maintained at 55°C until the particle size reached 6.0 µm, thereby obtaining a dispersion of aggregated particles. Thereafter, toner 10 was produced in the same manner as in Example 1. Table 5 shows the physical property values ​​of the obtained toner particles and the evaluation results of the toner.

[0130] Example 11 (Toner 11 production) A 3-L four-neck flask equipped with a dehydration tube, a stirrer, and a thermocouple was charged with 640 g of resin particle dispersion X-1, 160 g of resin particle dispersion Y-1, 52 g of release agent particle dispersion W-1, 52 g of release agent particle dispersion W-2, 101 g of colorant particle dispersion E-1, and 43 g of deionized water, and mixed. Next, while stirring the mixture at 25°C, 200 g of aqueous solution G-1 of water-soluble addition polymer F-1 was added, and a solution prepared by dissolving 51 g of ammonium sulfate in 866 g of deionized water and adding a 4.8 mass% potassium hydroxide aqueous solution to adjust the pH to 8.0 was added dropwise over 60 minutes at 25°C, and the mixture was then heated to 55°C over 1 hour, and the volume median particle diameter D of the aggregated particles was measured. 50 The temperature was maintained at 55°C until the particle size reached 6.0 µm, thereby obtaining a dispersion of aggregated particles. Thereafter, toner 11 was produced in the same manner as in Example 1. Table 5 shows the physical property values ​​of the obtained toner particles and the evaluation results of the toner.

[0131] Comparative Example 1 (Production of Toner 51) Except for not adding the aqueous solution of the water-soluble addition polymer, toner 51 was produced in the same manner as in Example 1. Table 5 shows the physical property values ​​of the obtained toner particles and the evaluation results of the toner.

[0132] Comparative Example 2 (Production of Toner 52) Toner 52 was produced in the same manner as in Example 1, except that 40 g of a 15% by mass aqueous solution of sodium dodecylbenzenesulfonate (product name "Neopelex G-15", manufactured by Kao Corporation, an anionic surfactant) was added instead of the aqueous solution G-1 of water-soluble addition polymer F-1. The physical property values ​​of the obtained toner particles and the evaluation results of the toner are shown in Table 5.

[0133] [Toner evaluation method] (Charge amount distribution of toner) 0.6 g of toner and 19.4 g of ferrite carrier (ferrite core, silicone coated, saturation magnetization: 71 Am2 / kg) were placed in a 50 mL polypropylene bottle "PP Sample Bottle Wide Mouth" (manufactured by Sanplatec Co., Ltd.) and stirred for 20 minutes in a ball mill. After that, 5 g was sampled and measured using a charge amount measuring device "q-test" (manufactured by Epping) under the following measurement conditions in a room temperature and humidity environment (temperature 25°C, relative humidity 50%). Toner Flow (mL / min): 160 Electrode Voltage (V): 4000 Deposition Time(s):2 The median q / d was the toner charge Q / d (fC / 10 μm), where the specific density was 1.2 g / cm 3 and Median Diameter is the volume median particle diameter of the toner D 50 The value of was adopted. The obtained Q / d was connected by lines in the range of -0.4 to 0.4 (fC / 10μm) to create a graph of the charge distribution. The charge distribution was evaluated by the half-value width of the maximum peak of the obtained graph (the width of the cut when the distribution is cut at half the value of the maximum peak height in the distribution). The smaller the half-value width, the narrower the charge distribution and the more excellent the charge stability. [Table 5]

[0134] As shown in Table 5, it was confirmed that all of the toners obtained in Examples 1 to 11 had excellent charge stability. On the other hand, the toners obtained in Comparative Example 1, in which no aqueous solution of water-soluble addition polymer F was used, and Comparative Example 2, in which an aqueous solution of sodium dodecylbenzenesulfonate, a low-molecular-weight anionic surfactant, was used instead of the aqueous solution of water-soluble addition polymer F, were found to have low charging stability and to be inferior to Examples 1 to 11.

Claims

1. A method for producing a toner for developing electrostatic images, comprising the following steps 1 and 2 in this order: Step 1: A step of adding an aqueous solution of a water-soluble addition polymer F of an aromatic group-containing monomer and a hydrophilic monomer to agglomerate resin particles containing a crystalline polyester resin in an aqueous medium to obtain agglomerated particles. Step 2: A step of fusing the aggregated particles obtained in step 1 to obtain fused particles

2. 2. The method for producing a toner for developing electrostatic images according to claim 1, wherein the amount of the water-soluble addition polymer F added is 0.2 parts by weight or more and 30 parts by weight or less per 100 parts by weight of the resin in the resin particles.

3. 3. The method for producing a toner for developing electrostatic images according to claim 1, wherein the content of the structural unit derived from the hydrophilic monomer in the water-soluble addition polymer F is from 5% by mass to 70% by mass.

4. 3. The method for producing a toner for developing electrostatic images according to claim 1, wherein the hydrophilic monomer is a monomer containing an anionic group.

5. 3. The method for producing a toner for developing electrostatic images according to claim 1, wherein the water-soluble addition polymer F has an acid value of 50 mgKOH / g or more and 500 mgKOH / g or less.

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