Method for manufacturing toner for electrostatic charge image development

Abstract

To provide a method for producing a toner for electrostatic charge image development in which, even if the solid content concentration of agglomerated particles is high, fused particles can be obtained, which are excellent in circularity of the fused particles and have a low coarse particle rate.SOLUTION: In a method for producing a toner for electrostatic charge image development, the following steps 1 and 3 are included in this order or the following steps 1 to 3 are included in this order. A step 1: a step of aggregating the resin particles X in an aqueous medium to obtain the aggregated particles 1. A step 2: a step of aggregating the resin particles Y on the aggregated particles 1 obtained in the step 1 to obtain the aggregated particles 2. A step 3: a step of heating the aggregated particles 1 obtained in the step 1 or the aggregated particles 2 obtained in the step 2 and fusing them to obtain the fused particles. In the step 3, an amphiphilic molecule having a naphthalene ring and the acidic substance are added.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a toner for electrostatic charge image development.

Background Art

[0002] In the field of electrophotography, with the development of electrophotographic systems, there is a demand for the development of electrophotographic toners that can cope with higher image quality and higher speed. In order to meet the requirement of higher image quality, as a method for obtaining toner with a narrow particle size distribution and small particle size, toner is manufactured by an aggregation integration method (emulsion aggregation method, aggregation fusion method) in which fine resin particles or the like are aggregated and fused in an aqueous medium. Among them, in order to improve thermal properties such as low-temperature fixability and heat-resistant storage stability, toners having a core-shell structure have been proposed.

[0003] For example, Patent Document 1 describes a method for manufacturing a toner for electrostatic charge image development including a step of fusing aggregated particles, which are aggregates of polyester resin particles, in an aqueous medium. In the step of fusing, at a temperature equal to or higher than the glass transition temperature of the polyester resin of the aggregated particles, and an acidic substance is added to lower the pH in the aqueous medium by 0.1 or more and 3.0 or less compared to before the addition of the acidic substance, and the pH after the addition of the acidic substance is in the range of 4.0 or more and 7.0 or less. Then, at a temperature equal to or higher than the glass transition temperature of the polyester resin of the aggregated particles, and a basic substance is added to raise the pH in the aqueous medium by 0.1 or more and less than 1.0 compared to before the addition of the basic substance.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The technique of Patent Document 1 allows for the progress of fusion by adjusting the pH within the system during the fusion process. Specifically, after allowing the fusion to progress under acidic conditions, a basic compound is added anew to obtain a toner with excellent cleaning properties. However, Patent Document 1 has a problem in that when the solid content concentration of the aggregated particles increases, the roundness of the fused particles decreases. The present invention relates to a method for manufacturing an electrostatic charge image developing toner, which can obtain fused particles having excellent roundness of the fused particles and a low coarse particle rate even when the solid content concentration of the aggregated particles is high.

Means for Solving the Problems

[0006] The present inventors have found that in a method for manufacturing an electrostatic charge image developing toner having an aggregation and fusion step, in the fusion, by adding a specific amphiphilic molecule and adding an acidic substance to lower the pH, fused particles having excellent roundness of the fused particles and a low coarse particle rate can be obtained.

[0007] That is, the present invention relates to the following [1]. [1] Including the following Step 1 and Step 3 in this order, or including the following Steps 1 to 3 in this order, Step 1: A step of aggregating resin particles X in an aqueous medium to obtain aggregated particles 1. Step 2: A step of aggregating resin particles Y with respect to the aggregated particles 1 obtained in Step 1 to obtain aggregated particles 2. Step 3: A step of heating and fusing the aggregated particles 1 obtained in Step 1 or the aggregated particles 2 obtained in Step 2 to obtain fused particles, In Step 3, an amphiphilic molecule having a naphthalene ring and an acidic substance are added. A method for manufacturing an electrostatic charge image developing toner.

Advantages of the Invention

[0008] According to the present invention, there is provided a method for manufacturing an electrostatic charge image developing toner, which can obtain fused particles having excellent roundness of the fused particles and a low coarse particle rate even when the solid content concentration of the aggregated particles is high.

Best Mode for Carrying Out the Invention

[0009] [Method for Producing Toner for Developing Electrostatic Charge Images] The method for producing a toner for developing an electrostatic charge image (hereinafter, also simply referred to as "toner") according to the present invention includes the following step 1 and step 3 in this order, or includes the following steps 1 to 3 in this order. Step 1: A step of aggregating resin particles X in an aqueous medium to obtain aggregated particles 1 (hereinafter, also referred to as "aggregation step 1"). Step 2: A step of aggregating resin particles Y with respect to the aggregated particles 1 obtained in step 1 to obtain aggregated particles 2 (hereinafter, also referred to as "aggregation step 2"). Step 3: A step of heating and fusing the aggregated particles 1 obtained in step 1 or the aggregated particles 2 obtained in step 2 to obtain fused particles, In step 3, an amphiphilic molecule having a naphthalene ring and an acidic substance are added.

[0010] According to the present invention, even when the solid content concentration of the aggregated particles is high, fused particles having excellent roundness and a low coarse particle ratio can be obtained. By increasing the solid content concentration of the aggregated particles and reducing the coarse particle ratio, productivity can be improved. Further, by improving the roundness of the fused particles, a toner excellent in high image quality can be obtained. The reason for obtaining the above effects is not clear, but it is considered as follows. The present invention relates to a method for producing a toner including a step of aggregating resin particles X to obtain aggregated particles 1 and then heating and fusing the aggregated particles 1, or a method for producing a toner including a step of aggregating resin particles X to obtain core aggregated particles 1 and then aggregating resin particles Y for forming a shell to obtain aggregated particles 2, and further heating and fusing the aggregated particles 2, and adding specific amphiphilic molecules and an acidic substance in the fusing step. For productivity improvement, in the fusing step, when the aggregated particles 1 or the aggregated particles 2 are at a high concentration, aggregation between the particles progresses, and it has been difficult to achieve the desired roundness. In the present invention, the above configuration enables this to be achieved. This is because in the fusion step, by adding specific amphiphilic molecules, the dispersibility of the aggregated particles 1 and aggregated particles 2 in step 3 is further improved, the aggregation of the aggregated particles 1 with each other and the aggregated particles 2 with each other is suppressed, and with an acidic substance, by lowering the pH, the acid groups of the aggregated particles, for example, when the acid group is a carboxy group, the repulsion between the carboxy groups is suppressed, and it is considered that this is because the fusion is promoted. Note that the above mechanism regarding the effects of the present invention is an estimation and is not limited thereto.

[0011] The definitions of various terms in this specification are shown below. Whether the resin is crystalline or amorphous is determined by the crystallinity index. The crystallinity index is defined as the ratio of the softening point of the resin to the maximum peak temperature of endotherm in the measurement method described in the examples described later (softening point (°C) / maximum peak temperature of endotherm (°C)). A crystalline resin is one having a crystallinity index of 0.6 or more and 1.4 or less. An amorphous resin is one having a crystallinity index of less than 0.6 or more than 1.4. The crystallinity index can be appropriately adjusted by the type and ratio of the raw material monomers, and production conditions such as reaction temperature, reaction time, and cooling rate. In the specification, the carboxylic acid component of the polyester resin includes not only the compound itself, but also anhydrides that decompose during the reaction to generate acids, and alkyl esters of each carboxylic acid (alkyl group having 1 to 3 carbon atoms). "Volume median particle diameter (D 50 )" is the particle diameter at which the cumulative volume frequency calculated by volume fraction becomes 50% when calculated from the smaller particle diameter side. The coefficient of variation of the particle size distribution (hereinafter, also simply referred to as "CV value") is a value represented by the following formula. The volume average particle diameter in the following formula is the particle diameter obtained by multiplying the particle diameter measured on a volume basis by the ratio of the particles having that particle diameter value and dividing the resulting value by the number of particles. CV value (%) = [standard deviation of particle size distribution (μm) / volume average particle diameter (μm)] × 100

[0012] <Step 1> In Step 1, resin particles X are aggregated in an aqueous medium to obtain aggregated particles 1. Here, in addition to the resin particles X, it is preferable to aggregate colorant particles and mold release agent particles, and it is more preferable to mix a resin particle dispersion containing the resin particles X, a colorant particle dispersion containing the colorant particles, and a mold release agent particle dispersion containing the mold release agent particles to aggregate these particles. 〔Resin Particles X〕 The resin particle dispersion used in Step 1 contains resin particles X. In order to obtain excellent low-temperature fixability, the resin particles X preferably contain an amorphous resin A and a crystalline polyester resin C in the same or different resin particles. From the viewpoint of further improving the low-temperature fixability of the resulting toner and widening the non-offset temperature range, preferably, the amorphous resin A and the crystalline polyester resin C are contained in the same resin particles.

[0013] ≪Amorphous Resin A≫ The amorphous resin A is, for example, an amorphous polyester-based resin A containing a polycondensate of an alcohol component and a carboxylic acid component. Examples of the amorphous polyester-based resin include polyester resins and modified polyester resins. Examples of the modified polyester resin include urethane-modified products of polyester resins, epoxy-modified products of polyester resins, and composite resins containing a polyester resin segment and an addition polymer resin segment. Among these, it is preferable to be an amorphous composite resin containing a polyester resin segment that is a polycondensate of an alcohol component and a carboxylic acid component and an addition polymer resin segment that is an addition polymer of a raw material monomer containing a styrene-based compound.

[0014] Examples of the alcohol component include alkylene oxide adducts of aromatic diols, linear or branched aliphatic diols, alicyclic diols, and polyhydric alcohols having a trivalent or higher valence. Among these, from the viewpoint of obtaining a toner with excellent low-temperature fixability, alkylene oxide adducts of aromatic diols are preferable. The alkylene oxide adduct of the aromatic diol is preferably an alkylene oxide adduct of bisphenol A, more preferably of the formula (I):

[0015] [Chemical formula] (wherein, OR 1 and R 2 O is an oxyalkylene group, and R 1 and R 2 are each independently an ethylene group or a propylene group, x and y represent the average number of moles of alkylene oxide added, are each a positive number, and the value of the sum of x and y is 1 or more, preferably 1.5 or more, more preferably 1.8 or more, and 16 or less, preferably 8 or less, more preferably 4 or less, still more preferably 3 or less, and even more preferably 2.5 or less), which is an alkylene oxide adduct of bisphenol A.

[0016] Examples of the alkylene oxide adduct of bisphenol A include, for example, a propylene oxide adduct of bisphenol A [2,2-bis(4-hydroxyphenyl)propane] and an ethylene oxide adduct of bisphenol A. One or more of these may be used. Among these, a propylene oxide adduct of bisphenol A is preferred. The content of the alkylene oxide adduct of bisphenol A in the alcohol component is preferably 70 mol% or more, more preferably 90 mol% or more, still more preferably 95 mol% or more, and 100 mol% or less, and more preferably 100 mol%.

[0017] Examples of the linear or branched aliphatic diol 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, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, and 1,12-dodecanediol. Examples of the alicyclic diol include hydrogenated bisphenol A [2,2-bis(4-hydroxycyclohexyl)propane], and alkylene oxide adducts of hydrogenated bisphenol A having 2 to 4 carbon atoms (average addition mole number: 2 to 12). Examples of the trivalent or higher polyhydric alcohol include glycerin, pentaerythritol, trimethylolpropane, and sorbitol. These alcohol components may be used alone or in combination of two or more.

[0018] Examples of the carboxylic acid component include dicarboxylic acids and trivalent or higher polycarboxylic acids. Examples of the dicarboxylic acid include aromatic dicarboxylic acids, linear or branched aliphatic dicarboxylic acids, and alicyclic dicarboxylic acids. Among these, at least one selected from aromatic dicarboxylic acids and linear or branched aliphatic dicarboxylic acids is preferable. Examples of the aromatic dicarboxylic acid include phthalic acid, isophthalic acid, and terephthalic acid. Among these, isophthalic acid and terephthalic acid are preferable, and terephthalic acid is more preferable. The amount of the aromatic dicarboxylic acid is preferably 20 mol% or more, more preferably 30 mol% or more, still more preferably 40 mol% or more, still more preferably 50 mol% or more, and preferably 90 mol% or less, more preferably 85 mol% or less, still more preferably 80 mol% or less in the carboxylic acid component.

[0019] The carbon number of the linear or branched aliphatic dicarboxylic acid is preferably 2 or more, more preferably 3 or more, and preferably 30 or less, more preferably 20 or less. Examples of the linear or branched aliphatic dicarboxylic acid 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 acid substituted with an aliphatic hydrocarbon group having 1 to 20 carbon atoms. Examples of the succinic acid substituted with an aliphatic hydrocarbon group having 1 to 20 carbon atoms include dodecyl succinic acid, dodecenyl succinic acid, and octenyl succinic acid. Among these, fumaric acid, sebacic acid, and succinic acid substituted with an aliphatic hydrocarbon group having 1 to 20 carbon atoms are preferred. The amount of the linear or branched aliphatic dicarboxylic acid is preferably 1 mol% or more, more preferably 3 mol% or more, still more preferably 10 mol% or more, and preferably 80 mol% or less, more preferably 50 mol% or less, still more preferably 30 mol% or less in the carboxylic acid component.

[0020] The polyvalent carboxylic acid having a valency of 3 or more is preferably a trivalent carboxylic acid, and examples thereof include trimellitic acid. Preferably, it is trimellitic acid or its anhydride. When the polyvalent carboxylic acid having a valency of 3 or more is included, the amount of the polyvalent carboxylic acid having a valency of 3 or more is preferably 3 mol% or more, more preferably 5 mol% or more, still more preferably 8 mol% or more, and preferably 30 mol% or less, more preferably 25 mol% or less, still more preferably 20 mol% or less in the carboxylic acid component. These carboxylic acid components may be used alone or in combination of two or more.

[0021] The equivalent ratio [COOH group / OH group] of the carboxy group of the carboxylic acid component to the hydroxy group of the alcohol component is preferably 0.7 or more, more preferably 0.8 or more, and preferably 1.3 or less, more preferably 1.2 or less.

[0022] The addition polymerization resin segment is, for example, an addition polymer of a raw material monomer containing a styrene-based compound. Examples of styrene compounds include unsubstituted or substituted styrenes. Examples of substituents on styrene include alkyl groups having 1 to 5 carbon atoms, halogen atoms, alkoxy groups having 1 to 5 carbon atoms, sulfonic acid groups or salts thereof. Examples of styrene compounds include styrene, methylstyrene, α-methylstyrene, β-methylstyrene, tert-butylstyrene, chlorostyrene, chloromethylstyrene, methoxystyrene, styrenesulfonic acid or salts thereof. Among these, styrene is preferred. In the raw material monomers of the addition polymerization resin segment, the content of styrene compounds is preferably 50% by mass or more, more preferably 65% by mass or more, still more preferably 75% by mass or more, and is 100% by mass or less, preferably 95% by mass or less, more preferably 90% by mass or less, still more preferably 85% by mass or less.

[0023] Examples of raw material monomers other than styrene compounds include (meth)acrylic acid esters such as alkyl (meth)acrylates, benzyl (meth)acrylate, dimethylaminoethyl (meth)acrylate; olefins such as ethylene, propylene, butadiene; halovinyls such as vinyl chloride; vinyl esters such as vinyl acetate, vinyl propionate; vinyl ethers such as methyl vinyl ether; vinylidene chloride and other halogenated vinylidenes; N-vinyl compounds such as N-vinylpyrrolidone. Among these, (meth)acrylic acid esters are preferred, and alkyl (meth)acrylates are more preferred. The number of carbon atoms of the alkyl group in alkyl (meth)acrylate is preferably 1 or more, more preferably 4 or more, still more preferably 6 or more, and is preferably 24 or less, more preferably 22 or less, still more preferably 20 or less. Examples of the (meth)acrylic acid alkyl esters include methyl (meth)acrylate, ethyl (meth)acrylate, (iso)propyl (meth)acrylate, (iso- or tertiary)butyl (meth)acrylate, (iso)amyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, (iso)octyl (meth)acrylate, (iso)decyl (meth)acrylate, (iso)dodecyl (meth)acrylate, (iso)palmityl (meth)acrylate, (iso)stearyl (meth)acrylate, (iso)behenyl (meth)acrylate, etc. Preferred are 2-ethylhexyl (meth)acrylate or stearyl (meth)acrylate, more preferred is stearyl (meth)acrylate, and even more preferred is stearyl methacrylate. Note that “(iso- or tertiary)” and “(iso)” mean both cases with and without these prefixes, and when these prefixes are absent, it indicates normal. Also, “(meth)acrylic acid” indicates acrylic acid or methacrylic acid.

[0024] In the raw material monomers of the addition polymerization resin segment, the content of the (meth)acrylic acid ester is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 15% by mass or more, and preferably 50% by mass or less, more preferably 35% by mass or less, still more preferably 25% by mass or less. In the raw material monomers of the addition polymerization resin segment, the total amount of the styrene-based compound and the (meth)acrylic acid ester is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and even more preferably 100% by mass.

[0025] The amorphous polyester resin A preferably has structural units derived from both reactive monomers bonded via a covalent bond to the polyester resin segment and the addition polymerization resin segment. The “structural units derived from both reactive monomers” means the units obtained by the reaction of the functional groups and addition polymerizable groups of both reactive monomers. Examples of the additional polymerization group include carbon-carbon unsaturated bonds (ethylenic unsaturated bonds). Examples of the bifunctional monomer include addition-polymerizable monomers having at least one functional group selected from a hydroxyl group, a carboxy group, an epoxy group, a primary amino group, and a secondary amino group in the molecule. Among these, from the viewpoint of reactivity, addition-polymerizable monomers having at least one functional group selected from a hydroxyl group and a carboxy group are preferable, and addition-polymerizable monomers having a carboxy group are more preferable. Examples of the addition-polymerizable monomer having a carboxy group include acrylic acid, methacrylic acid, fumaric acid, and maleic acid. Among these, from the viewpoint of the reactivity of both the polycondensation reaction and the addition polymerization reaction, acrylic acid and methacrylic acid are preferable, and acrylic acid is more preferable. When the bifunctional monomer is an addition-polymerizable monomer having a carboxy group, the amount of the structural unit derived from the bifunctional monomer is preferably 1 mol part or more, more preferably 5 mol parts or more, still more preferably 8 mol parts or more, and preferably 30 mol parts or less, more preferably 25 mol parts or less, still more preferably 20 mol parts or less, relative to 100 mol parts of the alcohol component of the polyester resin segment of the amorphous polyester resin A.

[0026] The content of the polyester resin segment in the amorphous polyester resin A is preferably 35% by mass or more, more preferably 45% by mass or more, still more preferably 50% by mass or more, and preferably 90% by mass or less, more preferably 85% by mass or less, still more preferably 75% by mass or less.

[0027] The content of the addition-polymer resin segment in the amorphous polyester resin A is preferably 5% by mass or more, more preferably 15% by mass or more, still more preferably 25% by mass or more, and preferably 60% by mass or less, more preferably 55% by mass or less, still more preferably 45% by mass or less.

[0028] The amount of the structural unit derived from the both-reactive monomer in the amorphous polyester resin A is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, still more preferably 0.8% by mass or more, and is preferably 10% by mass or less, more preferably 7% by mass or less, still more preferably 4% by mass or less.

[0029] The total amount of the structural units derived from the polyester resin segment, the addition polymerization resin segment, and the both-reactive monomer in the amorphous polyester resin A is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and is 100% by mass or less, and still more preferably 100% by mass.

[0030] The above amount is calculated based on the ratio of the amounts of the polyester resin segment, the raw material monomers of the addition polymerization resin segment, the both-reactive monomer, and the radical polymerization initiator, and is based on the mass excluding the amount of water removed by polycondensation in the polyester resin segment or the like. When a radical polymerization initiator is used, the mass of the radical polymerization initiator is calculated including in the addition polymerization resin segment.

[0031] The amorphous polyester resin A may be produced, for example, by a method including a step A of polycondensing an alcohol component and a carboxylic acid component, and a step B of addition polymerizing the raw material monomers of the addition polymerization resin segment and the both-reactive monomer. Step B may be carried out after step A, step A may be carried out after step B, or step A and step B may be carried out simultaneously. In step A, a part of the carboxylic acid component is subjected to a polycondensation reaction, then step B is carried out, and then the remainder of the carboxylic acid component is added to the polymerization system, and the polycondensation reaction of step A and the polycondensation reaction with the carboxy group of the both-reactive monomer or the structural moiety derived from the both-reactive monomer are further advanced. This method is preferred.

[0032] In Project A, if necessary, esterification catalysts such as tin(II) bis(2-ethylhexanoate), dibutyltin oxide, and titanium diisopropoxybis(triethanolamine) may be used in an amount of 0.01 part by mass or more and 5 parts by mass or less based on 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component; esterification co-catalysts such as gallic acid (the same as 3,4,5-trihydroxybenzoic acid) may be used in an amount of 0.001 part by mass or more and 0.5 part by mass or less based on 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component for polycondensation. Also, when using a monomer having an unsaturated bond such as fumaric acid in the polycondensation, a radical polymerization inhibitor may be used, preferably in an amount of 0.001 part by mass or more and 0.5 part by mass or less based on 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component, if necessary. Examples of the radical polymerization inhibitor include 4-tert-butylcatechol. The temperature of the polycondensation reaction is preferably 120 °C or higher, more preferably 160 °C or higher, still more preferably 180 °C or higher, and preferably 250 °C or lower, more preferably 240 °C or lower. Note that the polycondensation may be carried out in an inert gas atmosphere.

[0033] Examples of the radical polymerization initiator for the addition polymerization in Step B include peroxides such as dibutyl peroxide, persulfates such as sodium persulfate, and azo compounds such as 2,2'-azobis(2,4-dimethylvaleronitrile). The amount of the radical polymerization initiator used is preferably 1 part by mass or more and 20 parts by mass or less based on 100 parts by mass of the raw material monomer of the addition polymerization resin segment. The temperature of the addition polymerization is preferably 110 °C or higher, more preferably 130 °C or higher, and preferably 230 °C or lower, more preferably 220 °C or lower, still more preferably 210 °C or lower.

[0034] (Physical properties of amorphous resin A) The softening point of the amorphous resin A is preferably 70°C or higher, more preferably 90°C or higher, still more preferably 100°C or higher, and from the viewpoint of further improving low-temperature fixability, it is preferably 150°C or lower, more preferably 140°C or lower, still more preferably 125°C or lower. The glass transition temperature of the amorphous resin A is preferably 30°C or higher, more preferably 35°C or higher, still more preferably 40°C or higher, and from the viewpoint of further improving low-temperature fixability, it is preferably 80°C or lower, more preferably 70°C or lower, still more preferably 60°C or lower.

[0035] The acid value of the amorphous resin A is preferably 5 mgKOH / g or higher, more preferably 10 mgKOH / g or higher, still more preferably 15 mgKOH / g or higher, and is preferably 40 mgKOH / g or lower, more preferably 35 mgKOH / g or lower, still more preferably 30 mgKOH / g or lower. The hydroxyl value of the amorphous resin A is preferably 1 mgKOH / g or higher, more preferably 3 mgKOH / g or higher, still more preferably 10 mgKOH / g or higher, and is preferably 60 mgKOH / g or lower, more preferably 40 mgKOH / g or lower, still more preferably 20 mgKOH / g or lower. The softening point, glass transition temperature, and acid value of the amorphous resin A can be appropriately adjusted according to the types and amounts of the raw material monomers used, as well as the production conditions such as the reaction temperature, reaction time, and cooling rate. Also, these values are determined by the method described in the examples. When using two or more types of the amorphous resin A in combination, it is preferable that the values of the softening point, glass transition temperature, and acid value obtained as their mixture are respectively within the aforementioned ranges.

[0036] The content of the amorphous resin A is preferably 40% by mass or higher, more preferably 50% by mass or higher, still more preferably 60% by mass or higher, still more preferably 65% by mass or higher, based on the total amount of the resin components of the resin particles X, and is preferably 95% by mass or lower, more preferably 90% by mass or lower, still more preferably 85% by mass or lower.

[0037] ≪Crystalline Polyester Resin C≫ Crystalline polyester resin C is a crystalline polyester resin which is, for example, a polycondensate of an alcohol component and a carboxylic acid component. The crystalline polyester resin is a polycondensate of an alcohol component and a carboxylic acid component. As the alcohol component, α,ω-aliphatic diol is preferable. The number of carbon atoms of the α,ω-aliphatic diol is preferably 2 or more, more preferably 4 or more, still more preferably 6 or more, and preferably 16 or less, more preferably 14 or less, still more preferably 12 or less. Examples of the α,ω-aliphatic diol 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, 1,14-tetradecanediol. Among these, 1,6-hexanediol, 1,10-decanediol, 1,12-dodecanediol are preferable, and 1,10-decanediol is more preferable.

[0038] The amount of the α,ω-aliphatic diol is preferably 80 mol% or more, more preferably 85 mol% or more, still more preferably 90 mol% or more, still more preferably 95 mol% or more in the alcohol component, and 100 mol% or less, still more preferably 100 mol%.

[0039] The alcohol component may contain other alcohol components different from the α,ω-aliphatic diol. Examples of the 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 of two or more.

[0040] As the carboxylic acid component, an aliphatic dicarboxylic acid is preferable, and a linear aliphatic dicarboxylic acid is more preferable. The number of carbon atoms of the aliphatic dicarboxylic acid is preferably 4 or more, more preferably 8 or more, still more preferably 10 or more, and preferably 14 or less, more preferably 12 or less. Examples of the aliphatic dicarboxylic acid include fumaric acid, sebacic acid, dodecanedioic acid, and tetradecanedioic acid. Among these, sebacic acid and dodecanedioic acid are preferable, and sebacic acid is more preferable. These carboxylic acid components may be used alone or in combination of two or more.

[0041] The amount of the aliphatic dicarboxylic acid is preferably 80 mol% or more, more preferably 85 mol% or more, still more preferably 90 mol% or more, still more preferably 95 mol% or more in the carboxylic acid component, and 100 mol% or less, and still more preferably 100 mol%.

[0042] The carboxylic acid component may contain other carboxylic acid components different from the aliphatic dicarboxylic acid. Examples of the other carboxylic acid components include aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid; polyvalent carboxylic acids having a valence of 3 or more. These carboxylic acid components may be used alone or in combination of two or more.

[0043] The equivalent ratio of the carboxy group of the carboxylic acid component to the hydroxy group of the alcohol component [COOH group / OH group] is preferably 0.7 or more, more preferably 0.8 or more, and preferably 1.3 or less, more preferably 1.2 or less.

[0044] Examples of the method for producing the crystalline polyester resin include the same examples as in Step A of the aforementioned amorphous polyester resin A.

[0045] (Physical properties of crystalline polyester resin C) From the viewpoint of the storage stability of the toner, the softening point of the crystalline polyester resin C is preferably 60°C or higher, more preferably 70°C or higher, still more preferably 80°C or higher, and from the viewpoint of further improving the low-temperature fixability, it is preferably 150°C or lower, more preferably 120°C or lower, still more preferably 100°C or lower. From the viewpoint of the storage stability of the toner, the melting point of the crystalline polyester resin C is preferably 50°C or higher, more preferably 60°C or higher, still more preferably 70°C or higher, and from the viewpoint of further improving the low-temperature fixability, it is preferably 100°C or lower, more preferably 90°C or lower, still more preferably 80°C or lower.

[0046] The acid value of the crystalline polyester resin C is preferably 5 mgKOH / g or higher, more preferably 10 mgKOH / g or higher, and preferably 35 mgKOH / g or lower, more preferably 25 mgKOH / g or lower, still more preferably 20 mgKOH / g or lower. The softening point, melting point, and acid value of the crystalline polyester resin C can be appropriately adjusted according to the types and amounts of the raw material monomers used, and the production conditions such as the reaction temperature, reaction time, and cooling rate, and are determined by the methods described in the examples below. When two or more kinds of the crystalline polyester resin C are used in combination, it is preferable that the values of the softening point, melting point, and acid value obtained as a mixture thereof are within the above ranges, respectively.

[0047] The content of the crystalline polyester resin C is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 15% by mass or more, and preferably 60% by mass or less, more preferably 50% by mass or less, still more preferably 40% by mass or less, still more preferably 35% by mass or less, based on the total amount of the resin components of the resin particles X. The mass ratio of the amorphous resin A to the crystalline polyester resin C [amorphous resin A / crystalline polyester resin C] is preferably 40 / 60 or higher, more preferably 50 / 50 or higher, still more preferably 60 / 40 or higher, still more preferably 65 / 35 or higher, and preferably 95 / 5 or lower, more preferably 90 / 10 or lower, still more preferably 85 / 15 or lower.

[0048] ≪Preparation of Resin Particle Dispersion≫ The preparation of a resin particle dispersion containing resin particles X, preferably a resin particle dispersion containing amorphous resin A and crystalline polyester resin C in the same or different resin particles, can be carried out using known methods, but it is preferably dispersed by the phase inversion emulsification method. Examples of the phase inversion emulsification method include a method of adding an aqueous medium to an organic solvent solution of a resin or a molten resin to cause phase inversion emulsification.

[0049] The organic solvent used for phase inversion emulsification is not particularly limited as long as it can dissolve the resin. From the viewpoint of facilitating phase inversion, for example, alcohol solvents such as ethanol, isopropanol, and isobutanol; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and diethyl ketone; ether solvents such as dibutyl ether, tetrahydrofuran, and dioxane; and acetate ester solvents such as ethyl acetate and isopropyl acetate can be mentioned. Among these, from the viewpoint of easy removal from the mixed solution after adding the aqueous medium, ketone solvents and acetate ester solvents are preferred, and methyl ethyl ketone, ethyl acetate, and isopropyl acetate are more preferred. It is preferable to add a neutralizing agent to the organic solvent solution. Examples of the neutralizing agent include basic substances. Examples of the basic substances include hydroxides of alkali metals 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 with respect to the acid groups of the resin contained in the resin particles X is preferably 10 mol% or more, more preferably 30 mol% or more, still more preferably 40 mol% or more, and preferably 90 mol% or less, more preferably 70 mol% or less, from the viewpoints of obtaining fine resin particles and improving dispersion stability. The equivalent amount (mol%) of the neutralizing agent used can be determined 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. Use equivalent (mol%) of neutralizing agent = 〔{Added mass (g) of neutralizing agent / Equivalent of neutralizing agent} / [{Weight-average acid value (mgKOH / g) of resin constituting resin particles X × Mass (g) of resin constituting resin particles X} / (56 × 1000)]〕× 100

[0050] While stirring the organic solvent solution or molten resin, an aqueous medium is gradually added to cause phase inversion. From the viewpoint of improving the dispersion stability of resin particles X, the temperature of the organic solvent solution when adding the aqueous medium is preferably at or above the glass transition temperature of the amorphous resin constituting resin particles X, more preferably 50°C or above, still more preferably 60°C or above, and preferably 85°C or below, more preferably 80°C or below. The contents of amorphous resin A and crystalline polyester resin C are as described above.

[0051] After phase inversion emulsification, if necessary, the organic solvent may be removed from the obtained dispersion by distillation or the like. In this case, the remaining amount of the organic solvent in the dispersion is preferably 1% by mass or less, more preferably 0.5% by mass or less, still more preferably substantially 0% by mass.

[0052] The volume median diameter (D 50 ) of resin particles X in the dispersion is preferably 0.05 μm or more, more preferably 0.08 μm or more, still more preferably 0.12 μm or more, and preferably 0.8 μm or less, more preferably 0.4 μm or less, still more preferably 0.3 μm or less, from the viewpoint of obtaining a toner that can provide high-quality images. The CV value of resin particles X in the dispersion is preferably 10% or more, more preferably 20% or more, and preferably 40% or less, more preferably 35% or less, still more preferably 30% or less, from the viewpoint of obtaining a toner that can provide high-quality images. The volume median diameter (D 50 ) and CV value of resin particles X are determined by the method described in the examples below.

[0053] When resin particles Xa containing amorphous resin A and resin particles Xc containing crystalline polyester resin C are mixed and used, resin particles Xa and Xc can be obtained by the same method as described above. The addition amounts of resin particles Xa and resin particles Xc are preferably amounts that become the contents of the aforementioned amorphous resin A and crystalline polyester resin C.

[0054] 〔Aqueous medium〕 In the present invention, the aqueous medium is a medium mainly composed of water. The water content in the aqueous medium is preferably 70% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, and 100% by mass or less. As the water, deionized water, ion-exchanged water, or distilled water is preferable. As components other than water that can constitute the aqueous medium together with water, organic solvents soluble in water 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 are used. Among these, alkyl alcohols having 1 to 5 carbon atoms are preferable, and methanol or ethanol is more preferable.

[0055] 〔Colorant particles〕 The colorant particles are preferably mixed with the above-described resin particle dispersion liquid as a colorant particle dispersion liquid in which colorant particles containing a colorant are dispersed in an aqueous medium.

[0056] ≪Colorant≫ In Step 1, it is preferable to aggregate colorant particles containing a colorant together with the resin particles X. As the colorant, all of dyes, pigments, etc. used as colorants for toners can be used. Examples of the colorant include carbon black, phthalocyanine blue, 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 a black toner or a color toner other than black.

[0057] (Coloring agent particle dispersion liquid) The coloring agent is preferably contained in the aggregated particles by mixing and aggregating with resin particles as a dispersion liquid of coloring agent particles. The coloring agent particle dispersion liquid is preferably obtained by dispersing a coloring agent and an aqueous medium using a dispersing machine such as a homogenizer or an ultrasonic disperser. From the viewpoint of improving the dispersion stability of the coloring agent, this dispersion is preferably carried out in the presence of an addition polymer (hereinafter, the addition polymer used for dispersing the coloring agent is also referred to as "addition polymer E") or a surfactant. Examples of the surfactant include nonionic surfactants, anionic surfactants, and cationic surfactants, and from the viewpoint of improving the dispersion stability of the coloring agent particles, an anionic surfactant is preferably used. Examples of the anionic surfactant include dodecylbenzenesulfonate, dodecyl sulfate, lauryl ether sulfate, and alkenyl succinate. Among these, dodecylbenzenesulfonate is preferred. From the viewpoint of improving the dispersion stability of the coloring agent, the content of the surfactant in the coloring agent particle dispersion liquid is preferably 1 part by mass or more, more preferably 5 parts by mass or more, still more preferably 10 parts by mass or more, and preferably 40 parts by mass or less, more preferably 30 parts by mass or less, based on 100 parts by mass of the coloring agent.

[0058] The addition polymer E is preferably an addition polymer of a raw material monomer containing an addition polymerizable monomer a having an aromatic group (hereinafter, also simply referred to as "monomer a"). More preferably, the addition polymer E contains a structural unit derived from the addition polymerizable monomer a having an aromatic group in the main chain. The raw material monomer of the addition polymer E preferably contains, in addition to the addition polymerizable monomer a having an aromatic group, an addition polymerizable monomer b having an ionic group (hereinafter, also simply referred to as "monomer b"). In addition, the raw material monomer of the addition polymer E, in addition to monomer b, more preferably further contains at least one selected from an addition polymerizable monomer c having a polyalkylene oxide group (hereinafter also simply referred to as "monomer c") or a macromonomer d (hereinafter also simply referred to as "monomer d").

[0059] The addition polymerizable monomer a having an aromatic group is preferably nonionic. Examples of the addition polymerizable monomer a having an aromatic group include a styrene-based compound a-1 and an aromatic group-containing (meth)acrylate a-2. Examples of the styrene-based compound a-1 include substituted or unsubstituted styrene. Examples of the substituent for styrene include an alkyl group having 1 to 5 carbon atoms, a halogen atom, an alkoxy group having 1 to 5 carbon atoms, a sulfo group, or a salt thereof. The molecular weight of the styrene-based compound a-1 is preferably 1,000 or less, more preferably 800 or less, still more preferably 500 or less, still more preferably 300 or less, and is preferably 80 or more, more preferably 90 or more, still more preferably 100 or more. Examples of the styrene-based compound a-1 include styrene, methylstyrene, α-methylstyrene, β-methylstyrene, tert-butylstyrene, chlorostyrene, chloromethylstyrene, methoxystyrene, styrenesulfonic acid, or a salt thereof. Among these, styrene is preferred. From the viewpoint of further improving the hot offset resistance and image quality, the amount of the styrene-based compound a-1 in the raw material monomers of the addition polymer E is preferably 1% by mass or more, more preferably 5% by mass or more, still more preferably 10% by mass or more, still more preferably 20% by mass or more, still more preferably 30% by mass or more, still more preferably 35% by mass or more, and is preferably 98% by mass or less, more preferably 80% by mass or less, still more preferably 65% by mass or less, still more preferably 50% by mass or less.

[0060] Examples of the aromatic group-containing (meth)acrylate a-2 include benzyl (meth)acrylate and phenoxyethyl (meth)acrylate. The molecular weight of the aromatic group-containing (meth)acrylate a-2 is preferably 1,000 or less, more preferably 800 or less, still more preferably 500 or less, and still more preferably 300 or less, and is preferably 160 or more. When using the aromatic group-containing (meth)acrylate a-2, from the viewpoint of further improving the hot offset resistance and image quality, the content of the aromatic group-containing (meth)acrylate a-2 in the raw material monomers of the addition polymer E is preferably 1% by mass or more, more preferably 5% by mass or more, still more preferably 10% by mass or more, and is preferably 50% by mass or less, more preferably 40% by mass or less, still more preferably 30% by mass or less.

[0061] From the viewpoint of further improving the image density, the amount of the addition polymerizable monomer a having an aromatic group in the raw material monomers of the addition polymer E is preferably 1% by mass or more, more preferably 5% by mass or more, still more preferably 10% by mass or more, still more preferably 20% by mass or more, still more preferably 30% by mass or more, still more preferably 35% by mass or more, and is preferably 98% by mass or less, more preferably 95% by mass or less, still more preferably 90% by mass or less, still more preferably 80% by mass or less, still more preferably 65% by mass or less, and still more preferably 50% by mass or less.

[0062] In monomer b, the ionic group means a group that dissociates ionically in water. Examples of the ionic group include a carboxy group, a sulfo group, a phosphoric acid group, an amino group, or salts thereof. From the viewpoint of improving the dispersion stability of the colorant particles, the ionic group is preferably an anionic group. As the anionic group, an acidic group or salts thereof are preferred, a carboxy group, a sulfo group, or salts thereof are more preferred, and a carboxy group or salts thereof are still more preferred. Examples of the addition-polymerizable monomer having a carboxy group include (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, and 2-methacryloyloxymethyl succinic acid. Among these, addition-polymerizable monomers having an anionic group are preferred, (meth)acrylic acid is more preferred, and methacrylic acid is even more preferred. When monomer b is contained, the amount of monomer b is preferably 2% by mass or more, more preferably 5% by mass or more, still more preferably 10% by mass or more, and preferably 40% by mass or less, more preferably 30% by mass or less, still more preferably 20% by mass or less in the raw material monomers of the addition polymer E.

[0063] The average number of moles of alkylene oxide added to the polyalkylene oxide group of monomer c is preferably 1 or more, more preferably 2 or more, still more preferably 3 or more, and preferably 30 or less, more preferably 20 or less, still more preferably 10 or less. Monomer c is preferably nonionic. Examples of monomer c include polyalkylene glycol (meth)acrylates such as polyethylene glycol (meth)acrylate and polypropylene glycol (meth)acrylate; alkoxypolyalkylene glycol (meth)acrylates such as methoxypolyethylene glycol (meth)acrylate; and aryloxypolyalkylene glycol (meth)acrylates such as phenoxy(ethylene glycol-propylene glycol copolymer)(meth)acrylate. When monomer c is contained, the amount of monomer c is preferably 3% by mass or more, more preferably 10% by mass or more, still more preferably 20% by mass or more, and preferably 50% by mass or less, more preferably 40% by mass or less, still more preferably 30% by mass or less in the raw material monomers of the addition polymer E.

[0064] Monomer d includes, for example, a styrene-based compound polymer having an addition polymerizable functional group at one end (hereinafter also referred to as "styrene-based macromonomer"). Examples of the addition polymerizable functional group include a vinyl group, an allyl group, and a (meth)acryloyl group. Among these, a (meth)acryloyl group is preferred. In monomer d, as the styrene-based compound, styrene is preferred. The number average molecular weight of monomer d is preferably 1,000 or more and 10,000 or less. The number average molecular weight is measured by gel permeation chromatography using chloroform containing 1 mmol / L of dodecyl dimethylamine as a solvent and polystyrene as a standard substance. Commercially available products of styrene-based macromonomers include, for example, "AS-6", "AS-6S", "AN-6", "AN-6S", "HS-6", "HS-6S" (manufactured by Toagosei Co., Ltd., etc.). When monomer d is contained, the amount of monomer d is preferably 3% by mass or more, more preferably 6% by mass or more, still more preferably 10% by mass or more, and preferably 30% by mass or less, more preferably 25% by mass or less, still more preferably 20% by mass or less in the raw material monomers of addition polymer E.

[0065] Furthermore, as the raw material monomers of addition polymer E, addition polymerizable monomers (other monomers) other than monomers a to d may be contained. Examples of other monomers include alkyl (meth)acrylates having an alkyl group with 1 to 22 carbon atoms (preferably 6 to 18 carbon atoms). When other monomers are contained, the amount of other monomers is preferably 40% by mass or less, more preferably 30% by mass or less, still more preferably 20% by mass or less, still more preferably 10% by mass or less, still more preferably 5% by mass or less in the raw material monomers of addition polymer E.

[0066] The weight-average molecular weight of the addition polymer E is preferably 3,000 or more, more preferably 5,000 or more, still more preferably 20,000 or more, still more preferably 40,000 or more, still more preferably 48,000 or more, from the viewpoint of further improving the image density, and is preferably 200,000 or less, more preferably 90,000 or less, still more preferably 60,000 or less, still more preferably 53,000 or less. The measurement of the weight-average molecular weight can be carried out by the method described in the examples.

[0067] The addition polymer E can be produced, for example, by copolymerizing raw material monomers by a known polymerization method. As the polymerization method, preferably, a solution polymerization method in which the raw material monomers are heated and polymerized together with a polymerization initiator, a polymerization chain transfer agent, etc. in a solvent. Examples of the polymerization initiator include peroxides such as dibutyl peroxide, persulfates such as sodium persulfate, and azo compounds such as 2,2'-azobis(2,4-dimethylvaleronitrile). The addition amount of the polymerization initiator is preferably 0.5 parts by mass or more and preferably 30 parts by mass or less with respect to 100 parts by mass of the raw material monomers. Examples of the polymerization chain transfer agent (also simply referred to as "chain transfer agent") include mercaptans such as 2-mercaptoethanol and 3-mercaptopropionic acid. The addition amount of the polymerization chain transfer agent is preferably 0.01 parts by mass or more and preferably 10 parts by mass or less with respect to 100 parts by mass of the raw material monomers. After completion of the polymerization reaction, the produced polymer may be isolated and purified by known methods such as reprecipitation from the reaction solution and solvent distillation.

[0068] In the colorant particles, the mass ratio of the colorant to the addition polymer E (colorant / addition polymer E) is preferably 50 / 50 or more, more preferably 60 / 40 or more, still more preferably 70 / 30 or more, still more preferably 75 / 25 or more, from the viewpoint of obtaining a toner excellent in hot offset resistance and image quality, and is preferably 95 / 5 or less, more preferably 90 / 10 or less, still more preferably 85 / 15 or less.

[0069] ≪Manufacturing Method of Colorant Particles and Colorant Particle Dispersion Liquid≫ The colorant particles are obtained, for example, by mixing a colorant and an addition polymer E. There is no particular limitation on the manufacturing method of the colorant particle dispersion liquid. It may be controlled to obtain colorant particles having a desired volume median diameter D 50 using a known kneader, disperser, etc., but preferably, it is obtained by mixing a colorant and a dispersion liquid of an addition polymer E using a bead mill or a homogenizer.

[0070] The manufacturing method of the colorant particles preferably includes: Step a: After mixing an addition polymer E and an organic solvent, mixing a neutralizing agent if necessary, and further mixing an aqueous medium to obtain a dispersion liquid of the addition polymer E; and Step b: A step of subjecting the dispersion liquid obtained in Step a and a colorant to a dispersion treatment to obtain a dispersion liquid of colorant particles (colorant particle dispersion liquid 2). This is a method having these steps. The inclusion of the organic solvent enables the addition polymer E to dissolve in the organic solvent, facilitating the adsorption of the addition polymer E to the colorant and further enhancing the dispersibility of the colorant. Also, it is preferable that Step b is a step of subjecting the dispersion liquid obtained in Step a and a colorant to a dispersion treatment using a bead mill or a homogenizer.

[0071] In Step a, first, it is preferable to mix the addition polymer E and the organic solvent to dissolve the addition polymer E. Examples of the organic solvent used here include alkyl alcohols having 1 to 3 carbon atoms, dialkyl ketones having a total of 3 to 5 carbon atoms, and cyclic ethers. Among these, dialkyl ketones having a total of 3 to 5 carbon atoms are preferable, and methyl ethyl ketone is more preferable. When the addition polymer E is synthesized by a solution polymerization method, the solvent used in the polymerization may be used as it is.

[0072] Examples of the neutralizing agent include basic substances. Examples of the basic substances include hydroxides of alkali metals such as sodium hydroxide and potassium hydroxide; nitrogen-containing basic substances such as ammonia, trimethylamine, and diethanolamine. The degree of neutralization of the addition polymer E is preferably 15 mol% or more, more preferably 20 mol% or more, still more preferably 40 mol% or more, still more preferably 60 mol% or more, still more preferably 70 mol% or more, and preferably 100 mol% or less, more preferably 95 mol% or less, still more preferably 90 mol% or less. Note that the degree of neutralization of the addition polymer E can be determined by the following formula. Degree of neutralization (mol%) = [{mass of neutralizing agent added (g) / equivalent of neutralizing agent} / {mass ratio of addition polymerizable monomer having an acidic group constituting addition polymer E × mass of addition polymer E (g) / molecular weight of addition polymerizable monomer having an acidic group}] × 100 In step a, examples of the apparatus used for mixing include a mixing and stirring apparatus equipped with an anchor blade, a dispersing blade, etc. The temperature during mixing is preferably 0°C or higher, more preferably 10°C or higher, and preferably 40°C or lower, more preferably 30°C or lower, still more preferably 25°C or lower. The mixing time is preferably 1 minute or more, more preferably 3 minutes or more, still more preferably 5 minutes or more, and preferably 30 hours or less, more preferably 10 hours or less, still more preferably 5 hours or less, still more preferably 3 hours or less, still more preferably 1 hour or less.

[0073] In step b, the mass ratio of the colorant to the addition polymer E [colorant / addition polymer E] is as described above. In step b, after mixing the dispersion obtained in step a and the colorant, it is preferably subjected to a dispersion treatment. Examples of the apparatus used for mixing in step b include the same apparatuses as those used for mixing in step a. The temperature during mixing in step b is preferably 0 °C or higher, more preferably 10 °C or higher, and preferably 40 °C or lower, more preferably 30 °C or lower, still more preferably 25 °C or lower. Also, the mixing time in step b is preferably 1 minute or longer, more preferably 10 minutes or longer, still more preferably 30 minutes or longer, and preferably 30 hours or shorter, more preferably 10 hours or shorter, still more preferably 5 hours or shorter, still more preferably 3 hours or shorter.

[0074] Examples of the apparatus used for the dispersion treatment in step b include kneaders such as roll mills and kneaders, homogenizers such as Microfluidics (manufactured by Microfluidics) and Starburst (manufactured by Sugino Machine Limited), paint shakers, and media dispersers such as bead mills. One or more of these apparatuses may be used. Among these, from the viewpoint of reducing the particle size of the pigment, bead mills and homogenizers are preferred. When using a homogenizer, the treatment pressure is preferably 60 MPa or higher, more preferably 100 MPa or higher, still more preferably 130 MPa or higher, and preferably 270 MPa or lower, more preferably 200 MPa or lower, still more preferably 180 MPa or lower. Also, the number of passes is preferably 5 or more, more preferably 8 or more, still more preferably 12 or more, and preferably 30 or less, more preferably 20 or less.

[0075] It is preferable to remove the organic solvent from the obtained colored pigment particle dispersion. Also, the colored pigment particle dispersion is preferably filtered through a wire mesh or the like to remove coarse particles and the like. Also, from the viewpoint of improving the productivity and storage stability of the dispersion, the addition polymer E of the colored pigment particles may be crosslinked. Also, various additives such as organic solvents, preservatives, and fungicides may be added to the colored pigment particle dispersion.

[0076] In the colorant particle dispersion, the colorant is preferably 5% by mass or more, more preferably 10% by mass or more, and preferably 50% by mass or less, more preferably 40% by mass or less, still more preferably 30% by mass or less, and still more preferably 25% by mass or less. The solid content concentration of the colorant particle dispersion is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 15% by mass or more, and preferably 50% by mass or less, more preferably 40% by mass or less, still more preferably 30% by mass or less.

[0077] The volume median diameter D of the colorant particles in the colorant particle dispersion 50 is preferably 0.05 μm or more, more preferably 0.07 μm or more, still more preferably 0.08 μm or more, and preferably 0.4 μm or less, more preferably 0.3 μm or less, still more preferably 0.2 μm or less, from the viewpoint of improving the image density. The CV value of the colorant particles in the colorant particle dispersion is preferably 10% or more, more preferably 15% or more, and preferably 45% or less, more preferably 40% or less, still more preferably 35% or less, from the viewpoint of improving the image density. The volume median diameter D of the colorant particles 50 and the CV value are measured by the method described in the examples.

[0078] The amount of the colorant particles is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, still more preferably 10 parts by mass or more, and preferably 40 parts by mass or less, more preferably 30 parts by mass or less, still more preferably 25 parts by mass or less, with respect to 100 parts by mass of the resin particles, from the viewpoint of further improving the image density. The content of the colorant in the toner particles is preferably 0.1% by mass or more, more preferably 1% by mass or more, still more preferably 5% by mass or more, and preferably 20% by mass or less, more preferably 15% by mass or less.

[0079] 〔Mixing conditions〕 In Step 1, it is preferable to mix resin particles X and colorant particles in an aqueous medium and aggregate the resin particles X and the colorant particles to obtain aggregated particles. The mixing of the resin particles X and the colorant particles is preferably carried out by mixing a resin particle dispersion containing the resin particles X and a colorant particle dispersion containing the colorant particles. Further, the resin particle dispersion is preferably an aqueous dispersion of resin particles, and the colorant particle dispersion is preferably an aqueous dispersion of colorant particles. In Step 1, it is preferable to aggregate mold release agent particles together with the resin particles X and the colorant particles.

[0080] ≪Mold Release Agent≫ In Step 1, it is preferable to aggregate mold release agent particles containing a mold release agent together with the resin particles X and the colorant particles. Examples of the mold release agent include hydrocarbon waxes such as polypropylene wax, polyethylene wax, polypropylene polyethylene copolymer wax; microcrystalline wax, paraffin wax, Fischer-Tropsch wax, Sasol wax or their oxides; ester waxes such as carnauba wax, montan wax or their deacidified waxes, fatty acid ester waxes; fatty acid amides, fatty acids, higher alcohols, and fatty acid metal salts. These may be used alone or in combination of two or more.

[0081] The melting point of the mold 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, still more preferably 120°C or lower, and even more preferably 100°C or lower. The content of the mold release agent in the toner particles is preferably 0.1% by mass or more, more preferably 1% by mass or more, still more preferably 5% by mass or more, and preferably 20% by mass or less, more preferably 15% by mass or less.

[0082] (Dispersion of Mold Release Agent Particles) The mold release agent is preferably incorporated into the aggregated particles by mixing and aggregating it as a dispersion of mold release agent particles with the resin particle dispersion and the colorant particle dispersion. Although the dispersion of the release agent particles can be obtained using a surfactant, it is preferably obtained by mixing the release agent with resin particles Z described later. By preparing the release agent particles using the release agent and resin particles Z, the release agent particles are stabilized by the resin particles Z, and it becomes possible to disperse the release agent in an aqueous medium without using a surfactant. In the dispersion of the release agent particles, it is considered to have a structure in which a large number of resin particles Z adhere to the surface of the release agent particles.

[0083] The resin constituting the resin particles Z for dispersing the release agent is preferably a polyester resin, and it is more preferable to use a composite resin D having a polyester resin segment and an addition-polymerized resin segment.

[0084] The softening point of the composite resin D is preferably 70°C or higher, more preferably 80°C or higher, still more preferably 85°C or higher, and preferably 140°C or lower, more preferably 120°C or lower, still more preferably 100°C or lower. From the viewpoints of obtaining fine resin particles and a fine release agent particle dispersion, the acid value of the composite resin D is preferably 5 mgKOH / g or higher, more preferably 10 mgKOH / g or higher, still more preferably 15 mgKOH / g or higher, still more preferably 20 mgKOH / g or higher, and preferably 40 mgKOH / g or lower, more preferably 35 mgKOH / g or lower, still more preferably 30 mgKOH / g or lower. From the viewpoints of obtaining fine resin particles and a fine release agent particle dispersion, the hydroxyl value of the composite resin D is preferably 5 mgKOH / g or higher, more preferably 10 mgKOH / g or higher, still more preferably 15 mgKOH / g or higher, still more preferably 20 mgKOH / g or higher, and preferably 40 mgKOH / g or lower, more preferably 35 mgKOH / g or lower, still more preferably 30 mgKOH / g or lower.

[0085] The suitable ranges of other resin properties of the composite resin D, suitable examples of the raw material monomers constituting the resin, etc. are the same as the examples shown for the amorphous polyester resin A. The dispersion of the resin particles Z can be obtained, for example, by the phase inversion emulsification method described above. The volume median diameter (D 50 ) of the resin particles Z is preferably 0.01 μm or more, more preferably 0.03 μm or more, and preferably 0.3 μm or less, more preferably 0.2 μm or less, from the viewpoint of the dispersion stability of the release agent particles. The CV value of the resin particles Z is preferably 10% or more, more preferably 15% or more, and preferably 40% or less, more preferably 35% or less, still more preferably 30% or less, from the viewpoint of the dispersion stability of the release agent particles. The volume median diameter (D 50 ) and the CV value of the resin particles Z are measured by the method described in the examples.

[0086] The release agent particle dispersion can be obtained, for example, by dispersing a release agent, a dispersion of the resin particles Z, and, if necessary, an aqueous medium at a temperature equal to or higher than the melting point of the release agent using a disperser such as a homogenizer, a high-pressure disperser, or an ultrasonic disperser. The heating temperature during dispersion is preferably equal to or higher than the melting point of the release agent and 80°C or higher, more preferably 85°C or higher, still more preferably 90°C or higher, and preferably less than a temperature 10°C higher than the softening point of the resin contained in the resin particles Z and 100°C or lower, more preferably 98°C or lower, still more preferably 95°C or lower.

[0087] The amount of the resin particles Z is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, still more preferably 20 parts by mass or more, and preferably 100 parts by mass or less, more preferably 70 parts by mass or less, still more preferably 50 parts by mass or less, per 100 parts by mass of the release agent.

[0088] The volume median diameter (D 50 ) of the release agent particles is preferably 0.05 μm or more, more preferably 0.2 μm or more, still more preferably 0.4 μm or more, and preferably 1 μm or less, more preferably 0.8 μm or less, still more preferably 0.6 μm or less, from the viewpoint of obtaining uniform aggregated particles by aggregation. The CV value of the release agent particles is preferably 10% or more, more preferably 20% or more, and preferably 40% or less, more preferably 35% or less, still more preferably 30% or less. The volume median diameter (D 50 ) and CV value of the release agent particles are measured by the method described in the examples.

[0089] The agglomerated particles 1 may further contain additives such as charge control agents, magnetic powders, fluidity improvers, conductivity adjusters, reinforcing fillers such as fibrous substances, antioxidants, anti-aging agents, and cleaning property improvers.

[0090] ≪Surfactant≫ In step 1, after preparing a mixed dispersion liquid by mixing a resin particle dispersion liquid and, if necessary, a colorant particle dispersion liquid and a release agent particle dispersion liquid, it is preferable to aggregate the resin particles X, the colorant particles, and the release agent particles. When preparing the mixed dispersion liquid, from the viewpoint of improving the dispersion stability of the resin particles X and optional components such as colorant particles and release agent particles added as necessary, it may be carried out in the presence of a surfactant. Examples of the surfactant include anionic surfactants such as alkylbenzene sulfonates and alkyl ether sulfates; nonionic surfactants such as polyoxyethylene alkyl ethers and polyoxyethylene alkenyl ethers. Further, as the surfactant, an amphiphilic molecule having a naphthalene ring described later may be used in an amount less than the amount used at the time of fusion. In this case as well, in the fusion step described later, an amphiphilic molecule having a naphthalene ring is separately added. The surfactant may be used singly or in combination of two or more. When using a surfactant, the amount used is preferably 0.1 part by mass or more, more preferably 0.5 part by mass or more, and preferably 10 parts by mass or less, more preferably 5 parts by mass or less, based on 100 parts by mass of the resin particles X as the total amount of the surfactant.

[0091] The dispersion of the aforementioned resin particles X and the mixing of optional components are carried out by conventional methods. From the viewpoint of efficiently performing aggregation, it is preferable to add a flocculant to the mixed dispersion obtained by the mixing.

[0092] ≪Flocculant≫ Examples of the flocculant include cationic surfactants of quaternary salts, organic flocculants such as polyethyleneimine; inorganic metal salts such as sodium sulfate, sodium nitrate, sodium chloride, calcium chloride, calcium nitrate; inorganic ammonium salts such as ammonium sulfate, ammonium chloride, ammonium nitrate; and inorganic flocculants such as divalent or higher metal complexes. From the viewpoint of improving aggregability and obtaining uniform aggregated particles, inorganic flocculants with a valence of 1 or more and 5 or less are preferable, inorganic metal salts and inorganic ammonium salts with a valence of 1 or more and 2 or less are more preferable, and ammonium sulfate is even more preferable. The flocculant may be added as it is, but it is preferably dissolved in an aqueous medium and added as an aqueous solution. Further, when the flocculant is added as an aqueous solution, the pH of the flocculant aqueous solution may be adjusted.

[0093] Using a flocculant, for example, to a mixed dispersion containing resin particles X at 0°C or higher and 40°C or lower, and optionally colorant particles and release agent particles, 5 parts by mass or more and 60 parts by mass or less of the flocculant is added based on 100 parts by mass of resin particles X, and the resin particles X and the colorant particles are aggregated in an aqueous medium to obtain aggregated particles 1. Further, from the viewpoint of promoting aggregation, it is preferable to raise the temperature of the dispersion after adding the flocculant.

[0094] The volume median diameter D of the aggregated particles 1 obtained in Step 1 50 is preferably 3 μm or more, more preferably 4 μm or more, still more preferably 5 μm or more, and is preferably 10 μm or less, more preferably 8 μm or less, still more preferably 7 μm or less. It is preferable to continue the aggregation process until the desired volume median diameter is reached.

[0095] <Step 2> Step 2 is a step of aggregating resin particles Y with respect to the aggregated particles 1 obtained in Step 1 to obtain aggregated particles 2. [Resin particles Y] The resin particle dispersion used in Step 2 contains resin particles Y, and the resin particles Y preferably contain a polyester resin B having an aromatic ring. In the present invention, as the resin constituting the shell portion, a polyester resin B having an aromatic ring is used, and in Step 3 described later, an amphiphilic molecule having a naphthalene ring is used, so that the affinity with the toner surface is high and the dispersibility of the aggregated particles 2 is high, which is preferable.

[0096] ≪Polyester resin B≫ The polyester resin B is preferably an amorphous polyester resin containing, for example, a polycondensate of an alcohol component and a carboxylic acid component. Examples of the polyester resin include a polyester resin and a modified polyester resin. Examples of the modified polyester resin include a urethane-modified product of a polyester resin, an epoxy-modified product of a polyester resin, and a composite resin containing a polyester resin segment and an addition polymerized resin segment. Among these, a polyester resin which is a polycondensate of an alcohol component and a carboxylic acid component is preferable.

[0097] Examples of the alcohol component include an alkylene oxide adduct of an aromatic diol from the viewpoint of obtaining a polyester resin having an aromatic ring. Among these, an alkylene oxide adduct of an aromatic diol is preferable from the viewpoint of obtaining a toner excellent in low-temperature fixability. The alkylene oxide adduct of an aromatic diol is preferably an alkylene oxide adduct of bisphenol A, more preferably the formula (I):

[0098] [Chemical formula] (In the formula, OR 1 and R 2 O is an oxyalkylene group, R 1 and R 2Each is independently an ethylene group or a propylene group, x and y represent the average number of moles of alkylene oxide added, and each is a positive number. The value of the sum of x and y is 1 or more, preferably 1.5 or more, more preferably 1.8 or more, and 16 or less, preferably 8 or less, more preferably 4 or less, still more preferably 3 or less, and still more preferably 2.5 or less), and is an alkylene oxide adduct of bisphenol A represented by

[0099] Examples of the alkylene oxide adduct of bisphenol A include a propylene oxide adduct of bisphenol A [2,2-bis(4-hydroxyphenyl)propane] and an ethylene oxide adduct of bisphenol A. These may be used alone or in combination of two or more. Among these, an ethylene oxide adduct of bisphenol A is more preferable. The content of the alkylene oxide adduct of bisphenol A in the alcohol component is preferably 70 mol% or more, more preferably 90 mol% or more, still more preferably 95 mol% or more, and 100 mol% or less, and still more preferably 100 mol%.

[0100] In addition to the above alkylene oxide adduct of bisphenol A, the amorphous polyester resin A may contain the linear or branched aliphatic diol, alicyclic diol, polyhydric alcohol having a trivalent or higher valence, etc. described above. These alcohol components may be used alone or in combination of two or more.

[0101] Examples of the carboxylic acid component include dicarboxylic acids and polyvalent carboxylic acids having a trivalent or higher valence. Examples of the dicarboxylic acid include aromatic dicarboxylic acids, linear or branched aliphatic dicarboxylic acids, and alicyclic dicarboxylic acids. Among these, at least one selected from aromatic dicarboxylic acids and linear or branched aliphatic dicarboxylic acids is preferable. Examples of the aromatic dicarboxylic acid include phthalic acid, isophthalic acid, and terephthalic acid. Among these, isophthalic acid and terephthalic acid are preferable, and terephthalic acid is more preferable. The amount of the aromatic dicarboxylic acid is preferably 40 mol% or more, more preferably 50 mol% or more, still more preferably 60 mol% or more, still more preferably 70 mol% or more, still more preferably 75 mol% or more, and preferably 90 mol% or less, more preferably 85 mol% or less, from the viewpoint of obtaining a desired aromatic ring concentration in the carboxylic acid component.

[0102] The number of carbon atoms of the linear or branched aliphatic dicarboxylic acid is preferably 2 or more, more preferably 3 or more, and preferably 30 or less, more preferably 20 or less. Examples of the linear or branched aliphatic dicarboxylic acid 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 acid substituted with an aliphatic hydrocarbon group having 1 to 20 carbon atoms. Examples of the succinic acid substituted with an aliphatic hydrocarbon group having 1 to 20 carbon atoms include dodecyl succinic acid, dodecenyl succinic acid, and octenyl succinic acid. Among these, adipic acid and succinic acid substituted with an aliphatic hydrocarbon group having 1 to 20 carbon atoms are preferable. The amount of the linear or branched aliphatic dicarboxylic acid is preferably 60 mol% or less, more preferably 30 mol% or less, still more preferably 15 mol% or less in the carboxylic acid component.

[0103] The polyvalent carboxylic acid having a valence of 3 or more is preferably a trivalent carboxylic acid, and examples thereof include trimellitic acid. Preferably, it is trimellitic acid or its anhydride. When a polyvalent carboxylic acid having a valence of 3 or more is included, the amount of the polyvalent carboxylic acid having a valence of 3 or more is preferably 3 mol% or more, more preferably 5 mol% or more, still more preferably 8 mol% or more, and preferably 30 mol% or less, more preferably 25 mol% or less, still more preferably 20 mol% or less in the carboxylic acid component. These carboxylic acid components may be used alone or in combination of two or more.

[0104] The equivalent ratio of the carboxy group of the carboxylic acid component to the hydroxyl group of the alcohol component [COOH group / OH group] is preferably 0.7 or more, more preferably 0.8 or more, and preferably 1.3 or less, more preferably 1.2 or less.

[0105] The polyester resin B may be produced, for example, by the step A of polycondensing an alcohol component and a carboxylic acid component. Step A is the same as step A described in the method for producing the amorphous polyester resin A, and the preferred ranges are also the same. In step A, if necessary, an esterification catalyst such as tin(II) bis(2-ethylhexanoate), dibutyltin oxide, titanium diisopropoxybis(triethanolamineate) may be used in an amount of 0.01 parts by mass or more and 5 parts by mass or less based on 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component; an esterification co-catalyst such as gallic acid (the same as 3,4,5-trihydroxybenzoic acid) may be used in an amount of 0.001 parts by mass or more and 0.5 parts by mass or less based on 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component for polycondensation. When using a monomer having an unsaturated bond such as fumaric acid in the polycondensation, a radical polymerization inhibitor may be used, if necessary, in an amount of preferably 0.001 parts by mass or more and 0.5 parts by mass or less based on 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. Examples of the radical polymerization inhibitor include 4-tert-butylcatechol. The temperature of the polycondensation reaction is preferably 120°C or higher, more preferably 160°C or higher, still more preferably 180°C or higher, and preferably 250°C or lower, more preferably 240°C or lower. The polycondensation may be carried out in an inert gas atmosphere.

[0106] (Physical properties of polyester resin B) Polyester resin B is preferably an amorphous polyester resin. The softening point of polyester resin B is preferably 70°C or higher, more preferably 90°C or higher, still more preferably 100°C or higher, and from the viewpoint of further improving low-temperature fixability, it is preferably 150°C or lower, more preferably 140°C or lower, still more preferably 125°C or lower. The glass transition temperature of polyester resin B is preferably 30°C or higher, more preferably 40°C or higher, still more preferably 50°C or higher, and from the viewpoint of further improving low-temperature fixability, it is preferably 90°C or lower, more preferably 80°C or lower, still more preferably 70°C or lower.

[0107] The acid value of polyester resin B is preferably 5 mgKOH / g or higher, more preferably 10 mgKOH / g or higher, still more preferably 15 mgKOH / g or higher, and is preferably 40 mgKOH / g or lower, more preferably 30 mgKOH / g or lower, still more preferably 25 mgKOH / g or lower. The hydroxyl value of polyester resin B is preferably 1 mgKOH / g or higher, more preferably 3 mgKOH / g or higher, still more preferably 10 mgKOH / g or higher, and is preferably 60 mgKOH / g or lower, more preferably 50 mgKOH / g or lower, still more preferably 45 mgKOH / g or lower. The softening point, glass transition temperature, and acid value of polyester resin B can be appropriately adjusted by the types and amounts of raw material monomers used, as well as production conditions such as reaction temperature, reaction time, and cooling rate. Moreover, those values are determined by the methods described in the examples. When using two or more kinds of polyester resin B in combination, it is preferable that the values of the softening point, glass transition temperature, and acid value obtained as their mixture are respectively within the aforementioned ranges.

[0108] The content of the polyester resin B is preferably 60% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, still more preferably 95% by mass or more, and 100% by mass or less, and more preferably 100% by mass, based on the total amount of the resin components of the resin particles Y.

[0109] (Preparation of the resin particle Y dispersion) The resin particles Y are preferably produced by a method in which a resin component containing the polyester resin B and optional components such as a surfactant, if necessary, are dispersed in an aqueous medium to obtain a resin particle Y dispersion. As a method for obtaining the resin particle Y dispersion, the same methods as those for the resin particle dispersion of the resin particles X are exemplified. Among these, from the viewpoint of improving the low-temperature fixability of the resulting toner, it is preferable to obtain the resin particle Y dispersion by a phase inversion emulsification method. As in the case of the resin particles X, as the phase inversion emulsification method, a method in which an aqueous medium is added to a solution obtained by dissolving a resin and optional components such as a surfactant in an organic solvent and phase inversion emulsification is preferably used. Preferred embodiments of the aqueous medium and the organic solvent that can be used are the same as those of the aqueous medium and the organic solvent used in the production of the resin particles X. Also, the preferred ranges of the mass ratio of the polyester resin B to the organic solvent, the degree of neutralization of the polyester resin B, the amount of the aqueous medium to be added, the mixing temperature, etc. in the phase inversion emulsification method are the same as those in the production of the resin particles X.

[0110] The solid content concentration of the obtained resin particle Y dispersion is preferably 7% by mass or more, more preferably 10% by mass or more, still more preferably 15% by mass or more, still more preferably 20% by mass or more, and preferably 50% by mass or less, more preferably 35% by mass or less, from the viewpoints of improving the productivity of the toner and the dispersion stability of the resin particles Y. The solid content is the total amount of non-volatile components such as resin and surfactant.

[0111] The volume median particle diameter (D of the resin particles Y in the resin particle dispersion 50) is preferably 0.04 μm or more, more preferably 0.06 μm or more, still more preferably 0.08 μm or more, and preferably 0.5 μm or less, more preferably 0.3 μm or less, still more preferably 0.2 μm or less, and still more preferably 0.15 μm or less, from the viewpoint of obtaining a toner that can provide a high-quality image.

[0112] Also, the coefficient of variation (CV value) (%) of the particle size distribution of resin particles Y is preferably 5% or more, more preferably 10% or more, still more preferably 15% or more, from the viewpoint of improving the productivity of the resin particles Y dispersion liquid, and preferably 50% or less, more preferably 40% or less, still more preferably 30% or less, and still more preferably 25% or less, from the viewpoint of obtaining a toner that can provide a high-quality image. The volume median particle size (D 50 ) and the coefficient of variation (CV value) of resin particles Y are measured by the method described in the examples.

[0113] (Production of Aggregated Particles 2) In Step 2, it is preferable to obtain a dispersion liquid of aggregated particles 2 by adding a dispersion liquid of resin particles Y to the dispersion liquid of the aforementioned aggregated particles 1, so that resin particles Y are further adhered to the aggregated particles 1.

[0114] Before adding the dispersion liquid of resin particles Y to the dispersion liquid of aggregated particles 1, an aqueous medium may be added to the dispersion liquid of aggregated particles 1 for dilution. Also, when adding the dispersion liquid of resin particles Y to the dispersion liquid of aggregated particles 1, the flocculant may be used in this step in order to efficiently adhere resin particles Y to the aggregated particles 1. The temperature at the time of adding the dispersion liquid of resin particles Y is preferably 40°C or more, more preferably 45°C or more, still more preferably 50°C or more, and preferably 80°C or less, more preferably 70°C or less, still more preferably 60°C or less, from the viewpoint of achieving both low-temperature fixability and heat-resistant storage stability of the toner.

[0115] The resin particle Y dispersion may be added continuously over a certain period of time, added all at once, or added in multiple divided portions. However, it is preferable to add it continuously over a certain period of time or to add it in multiple divided portions. By adding it as described above, the resin particles Y are likely to selectively adhere to the aggregated particles 1. Among them, from the viewpoints of promoting selective adhesion and improving the productivity of the toner, it is preferable to add it continuously over a certain period of time. The time for continuous addition is preferably 0.5 hours or more, more preferably 0.8 hours or more, and preferably 10 hours or less, more preferably 7 hours or less, still more preferably 3 hours or less, from the viewpoints of obtaining uniform aggregated particles 2 and improving the productivity of the toner.

[0116] From the viewpoint of achieving both low-temperature fixability and heat-resistant storage stability of the toner, the addition amount of the resin particles Y is such that the mass ratio of the resin particles Y to the resin particles X (resin particles Y / resin particles X) is preferably 0.05 or more, more preferably 0.1 or more, and preferably 0.9 or less, more preferably 0.5 or less, still more preferably 0.3 or less, still more preferably 0.2 or less.

[0117] The volume median diameter (D 50 ) of the obtained aggregated particles 2 is preferably 2 μm or more, more preferably 3 μm or more, still more preferably 4 μm or more, and preferably 10 μm or less, more preferably 8 μm or less, still more preferably 7 μm or less, from the viewpoints of obtaining a toner that can provide high-quality images and achieving both low-temperature fixability and heat-resistant storage stability of the toner.

[0118] <Step 3> Step 3 is a step of heating and fusing the aggregated particles 1 obtained in Step 1 or the aggregated particles 2 obtained in Step 2 to obtain fused particles. In Step 3, an amphiphilic molecule having a naphthalene ring and an acidic substance are added. The amphiphilic molecule having a naphthalene ring is added for the purpose of improving the dispersion stability of the aggregated particles during fusion. The acidic substance is added for the purpose of promoting fusion by lowering the pH. The amphiphilic molecule having a naphthalene ring may be present even during the aggregation in Step 1 or Step 2. However, in Step 3, from the viewpoint of maintaining the dispersion stability during fusion, after adding the amphiphilic molecule having a naphthalene ring, it is preferable to raise the temperature and then perform fusion.

[0119] 〔Amphiphilic molecule having a naphthalene ring〕 The amphiphilic molecule having a naphthalene ring is an amphiphilic molecule having a surfactant effect, and is preferably an anionic surfactant. Examples of the amphiphilic molecule having a naphthalene ring include naphthalene sulfonate and naphthalene sulfonic acid formalin condensate, and naphthalene sulfonic acid formalin condensate is preferable. As the naphthalene sulfonate, an alkali metal salt of naphthalene sulfonic acid is preferable, and sodium naphthalene sulfonate is more preferable. Further, the naphthalene sulfonic acid formalin condensate is preferably a formaldehyde condensate of unsubstituted or substituted naphthalene sulfonic acid, and more preferably a compound represented by the following formula (1).

[0120]

Chemical formula

[0121] In formula (1), n preferably represents an integer of 2 or more and 200 or less, more preferably 6 or more and 100 or less, and still more preferably 10 or more and 50 or less. M each independently represents a cation, a cation of an element selected from Group 1 elements and Group 2 elements of the periodic table of elements; a quaternary ammonium; and ammonium (NH4 + ). Among these, a cation of a Group 1 element of the periodic table of elements is preferable; a cation of an element selected from lithium, sodium, and potassium is more preferable, and a sodium cation is still more preferable. Also, a plurality of M are preferably the same cation. The plurality of Rs each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a hydroxyl group, and from the viewpoint of improving heat storage stability, each independently is preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. More preferably, at least a part of the plurality of Rs is an alkyl group having 1 to 4 carbon atoms. In addition, within a range that does not impair the effect as a dispersion stabilizer, a part may have other constitutional units. Examples of the other constitutional units include constitutional units formed from copolymerizable monomers such as alkyl alcohol naphthalene sulfonic acid. The content of these constitutional units is preferably 30% by mass or less. As the naphthalene sulfonic acid formalin condensate, an unsubstituted or substituted sodium salt of β-naphthalene sulfonic acid formalin condensate is preferred.

[0122] From the viewpoint of improving heat storage stability, the weight average molecular weight of the naphthalene sulfonic acid formalin condensate is preferably 500 or more, more preferably 1,500 or more, still more preferably 2,500 or more, and preferably 40,000 or less, more preferably 20,000 or less, still more preferably 10,000 or less. The weight average molecular weight of the naphthalene sulfonic acid formalin condensate is measured by GPC.

[0123] The naphthalene sulfonic acid formalin condensate can be produced by a known method, for example, by polycondensing β-naphthalene sulfonic acid (salt), an equivalent amount of formalin, and other components as required. Examples of the other components include sulfonic acids (salts) such as β-methylnaphthalene, α-methylnaphthalene, acenaphthene, dibenzofuran, fluorene, phenanthrene, anthracene, fluoranthene, and pyrene. As the naphthalene sulfonic acid formalin condensate, commercially available products may be used. For example, Demol N, Demol NL, Demol RN, Demol RN-L, Demol T, Demol T-45, Demol MS, Demol SN-B, Demol SS-L, Demol SC-30 manufactured by Kao Corporation; Labelin AN-40, Labelin F-45, Labelin FC-45, Labelin FC-P, Labelin FD-40, Labelin FP, Labelin FN-P, Labelin MN-P manufactured by Daiichi Kogyo Seiyaku Co., Ltd.; Ionet D-2 manufactured by Sanyo Chemical Industries, Ltd. are exemplified.

[0124] From the viewpoint of obtaining fused particles with excellent roundness and a low coarse particle ratio, the addition amount of the amphiphilic molecule having a naphthalene ring in Step 3 is preferably 1.0 part by mass or more, more preferably 1.5 part by mass or more, still more preferably 3 part by mass or more, and preferably 30 part by mass or less, more preferably 20 part by mass or less, still more preferably 15 part by mass or less, still more preferably 12 part by mass or less, based on 100 parts by mass of Agglomerated Particle 1 or Agglomerated Particle 2. Also, from the viewpoint of obtaining fused particles with excellent roundness and a low coarse particle ratio, in Step 3, among the amphiphilic molecules added to the agglomerated particles, the amphiphilic molecule having a naphthalene ring is preferably 90% by mass or more, more preferably 95% by mass or more, and 100% by mass or less, and still more preferably 100% by mass.

[0125] In the present embodiment, in Step 3, it is preferable to add an acidic substance to lower the pH of the aqueous medium by 0.1 or more. That is, the pH in the aqueous medium means the pH of the aqueous medium containing the agglomerated particles. For example, using a pH meter, the electrode of the pH meter is immersed in the dispersion for fusion, and the pH is measured when the acidic substance is added. Preferably, the pH of the aqueous medium is lowered by 0.1 or more, more preferably 0.15 or more. Also, it is preferable to lower the pH to 4.0 or less, more preferably 3.0 or less, still more preferably 2.0 or less, and still more preferably 1.0 or less. Lowering the pH of the aqueous medium within the above range is preferable because the repulsion between the agglomerated particles is moderately weakened and fusion is promoted. In Step 3, when the aggregated particles 1 obtained in Step 1 are heated to cause fusion to obtain fused particles, it is preferable to add an acidic substance such that the acid groups (carboxy groups) of the resin particles X are preferably at least the molar equivalent, more preferably at least twice the molar equivalent, and preferably at most 20 times the molar equivalent, more preferably at most 10 times the molar equivalent. Further, in the case of heating and fusing the aggregated particles 2 obtained in Step 2 to obtain fused particles, it is preferable to add an acidic substance such that the acid groups (carboxy groups) of the resin particles Y constituting the shell structure are preferably at least the molar equivalent, more preferably at least twice the molar equivalent, and preferably at most 20 times the molar equivalent, more preferably at most 10 times the molar equivalent.

[0126] In Step 3, from the viewpoint of obtaining fused particles having excellent roundness and a low coarse particle ratio, the pH of the aqueous medium after adding the acidic substance is preferably 5.0 or higher, more preferably 6.0 or higher, still more preferably 6.5 or higher, and preferably 7.0 or lower, more preferably 6.9 or lower.

[0127] Examples of the acidic substance to be added include inorganic acids and organic acids. Examples of the inorganic acids include nitric acid, sulfuric acid, hydrochloric acid, and phosphoric acid. Examples of the organic acids include carboxylic acid compounds such as carboxylic acids, dicarboxylic acids, and tricarboxylic acids, sulfonic acid compounds such as methanesulfonic acid, benzenesulfonic acid, and toluenesulfonic acid, ascorbic acid, phenol, and cresol. Among these, carboxylic acid compounds are preferred. Examples of the carboxylic acid compounds include acetic acid, lactic acid, tartaric acid, propionic acid, benzoic acid, oxalic acid, terephthalic acid, fumaric acid, succinic acid, acrylic acid, and adipic acid. Among these, from the viewpoint of obtaining fused particles having excellent roundness and a low coarse particle ratio, inorganic acids are preferred, and sulfuric acid is more preferred.

[0128] From the viewpoint of obtaining fused particles having excellent roundness and a low coarse particle ratio, the acidic substance is preferably added into the system as an aqueous solution of the acidic substance. When adding as an aqueous solution of an acidic substance, the concentration of the acidic substance in the aqueous solution of the acidic substance is preferably 0.01 mol / L or more, more preferably 0.03 mol / L or more, still more preferably 0.05 mol / L or more, and preferably 3 mol / L or less, more preferably 2 mol / L or less, still more preferably 1.5 mol / L or less, still more preferably 1 mol / L or less, still more preferably 0.5 mol / L or less, still more preferably 0.3 mol / L or less.

[0129] As a method for adding the acidic substance, any of a method of adding all at once, a method of dividing the total amount into two or more portions and adding, and a method of continuously adding over a certain period of time may be used. Also, the addition of the acidic substance may be before adding the amphiphilic molecule having a naphthalene ring, after adding, before raising the temperature, or after raising the temperature, and is not particularly limited. However, from the viewpoint of obtaining fused particles having excellent roundness and a low coarse particle rate, it is preferable to add the acidic substance after adding the amphiphilic molecule having a naphthalene ring. More preferably, after adding the amphiphilic molecule having a naphthalene ring and raising the temperature, the acidic substance is added, and then it is held at the raised temperature.

[0130] In Step 3, each of the particles that were mainly physically attached to each other in the aggregated particles is fused into one body, and toner particles having a core-shell structure are formed. In this step, from the viewpoint of improving the fusibility of the aggregated particles and from the viewpoint of obtaining fused particles having excellent roundness and a low coarse particle rate, it is preferable to hold at a temperature equal to or higher than the glass transition temperature of the polyester resin B. The holding temperature in the fusing step is, from the viewpoint of improving the fusibility of the aggregated particles and from the viewpoint of improving the productivity of the toner, preferably a temperature 2°C or higher, more preferably 3°C or higher, still more preferably 5°C or higher than the glass transition temperature of the polyester resin B, and preferably a temperature 30°C or lower, more preferably 20°C or lower, still more preferably 15°C or lower than the glass transition temperature of the polyester resin B. At that time, the holding time at a temperature equal to or higher than the glass transition temperature of the polyester resin B may be appropriately set within a range in which the circularity of the fused particles falls within a desired range. From the viewpoint of productivity, it is preferably 240 minutes or less, more preferably 180 minutes or less, still more preferably 120 minutes or less, and even more preferably 100 minutes or less, and is preferably 1 minute or more, more preferably 10 minutes or more, and still more preferably 30 minutes or more. It is preferable to hold at the above temperature until the desired circularity is achieved.

[0131] In Step 3, it is preferable from the viewpoint of productivity that the solid content concentration of the aggregated particles 1 or the aggregated particles 2 is high. The solid content concentration of the aggregated particles 1 or the aggregated particles 2 at the time of holding at the temperature after the temperature increase described above is preferably 7% by mass or more, more preferably 8% by mass or more, still more preferably 9% by mass or more, and from the viewpoint of obtaining fused particles with excellent circularity and a low coarse particle rate, it is preferably 20% by mass or less, more preferably 15% by mass or less, still more preferably 12% by mass or less, and even more preferably 10% by mass or less. The solid content concentration of the aggregated particles 1 or the aggregated particles 2 in Step 3 is the mass ratio of the total amount of the resin particles X, the release agent particles, the colorant particles, and the resin particles Y to the total amount in the system at the time of holding at the temperature after the temperature increase in Step 3, and does not include solids such as the flocculant, pH adjuster, and amphiphilic molecules in the system. The solid content concentration of the aggregated particles 1 or the aggregated particles 2 in Step 3 can be determined by dividing the solid content of the aggregated particles 1 or the aggregated particles 2 by the total amount in Step 3.

[0132] The volume median particle diameter (D 50 ) of the fused particles obtained in Step 3 is preferably 2 μm or more, more preferably 3 μm or more, still more preferably 4 μm or more, and even more preferably 5 μm or more from the viewpoint of achieving both low-temperature fixability and heat-resistant storage stability of the toner, and is preferably 10 μm or less, more preferably 8 μm or less, and still more preferably 7 μm or less. Note that the volume median particle diameter of the fused particles obtained in Step 3 is preferably about the same as or smaller than the volume median particle diameter of the aggregated particles 1 or 2, and more preferably 0.9 times or more and 1.1 times or less the volume median particle diameter of the aggregated particles 1 or 2. That is, in this Step 3, it is preferable that aggregation and fusion do not occur between the aggregated particles 1 or 2.

[0133] <Post-treatment step> In the present invention, a post-treatment step may be performed after Step 3, and it is preferable to obtain toner particles by isolation. It is preferable to cool the dispersion of the fused particles obtained in Step 3, remove coarse particles, and then perform solid-liquid separation. For solid-liquid separation, a suction filtration method or the like is preferably used. For example, the removal of coarse particles can be performed by passing through a 300-mesh sieve (pore diameter 45 μm). It is preferable to perform washing after solid-liquid separation. At this time, since it is preferable to remove the added surfactant or the like, when the surfactant has a cloud point, it is preferable to wash with an aqueous medium below the cloud point of the surfactant. It is preferable to perform washing a plurality of times.

[0134] The circularity of the fused particles obtained in Step 3 after removing coarse particles is preferably 0.955 or more, more preferably 0.960 or more, still more preferably 0.965 or more, from the viewpoint of obtaining a toner for electrostatic charge image development with high image quality, and preferably 0.990 or less, more preferably 0.985 or less, still more preferably 0.980 or less, from the viewpoint of improving cleaning performance.

[0135] The volume median particle diameter D of the fused particles after removing coarse particles 50 is preferably 2 μm or more, more preferably 3 μm or more, still more preferably 4 μm or more, from the viewpoints of improving the productivity of the toner and obtaining a high-quality image, and preferably 10 μm or less, more preferably 8 μm or less, still more preferably 7 μm or less.

[0136] The CV value of the fused particles after removing the coarse particles is preferably 10% or more, more preferably 15% or more, still more preferably 20% or more, and preferably 50% or less, more preferably 40% or less, still more preferably 35% or less, from the viewpoints of improving the productivity of the toner and obtaining high-quality images.

[0137] Next, it is preferable to perform drying. The temperature during drying is preferably such that the temperature of the core-shell particles themselves is lower than the glass transition temperature of the amorphous resin A, and more preferably 10 °C or lower. As the drying method, it is preferable to use a vacuum low-temperature drying method, a vibration-type fluidized drying method, a spray drying method, a freeze drying method, a flash jet method, or the like.

[0138] The coarse particle ratio in the obtained fused particles is preferably low, preferably 6.0% or less, more preferably 5.0% or less, still more preferably 4.0% or less, and still more preferably 3.5% or less. The lower limit is not particularly limited, but from the viewpoint of ease of production, it is preferably 0.5% or more. The coarse particle ratio is measured by the method described in the examples.

[0139] (Toner particles) The toner particles obtained by separating the above-mentioned fused particles, washing them if necessary, and then performing drying or the like can be used as they are as the toner for electrostatic charge image development, but it is preferable to use those obtained by treating the surface of the toner particles as the toner for electrostatic charge image development as described below. The volume median particle diameter (D 50 ) of the toner particles is preferably 2 μm or more, more preferably 3 μm or more, still more preferably 4 μm or more, and preferably 10 μm or less, more preferably 8 μm or less, still more preferably 7 μm or less, from the viewpoints of improving the productivity of the toner and achieving both low-temperature fixability and heat-resistant storage stability of the toner. The CV value of the toner particles is preferably 10% or more, more preferably 15% or more, still more preferably 20% or more from the viewpoint of improving the productivity of the toner, and is preferably 50% or less, more preferably 40% or less, still more preferably 35% or less from the viewpoint of obtaining a high-quality image. The circularity of the toner particles is preferably 0.955 or more, more preferably 0.960 or more, still more preferably 0.965 or more from the viewpoint of obtaining a toner for electrostatic charge image development that can provide high image quality, and is preferably 0.990 or less, more preferably 0.985 or less, still more preferably 0.980 or less from the viewpoint of improving cleaning performance.

[0140] (External additive) Although the toner particles can be used as the toner as they are, it is preferable to use those obtained by adding a fluidizing agent or the like as an external additive to the surface of the toner particles as the toner. Examples of the external additive include inorganic fine particles such as hydrophobic silica, titanium oxide fine particles, alumina fine particles, cerium oxide fine particles, and carbon black, and polymer fine particles such as polycarbonate, polymethyl methacrylate, and silicone resin. Among these, hydrophobic silica is preferable. The external additive may be used alone or in combination of two or more. Also, the same type of external additive having different particle sizes may be used in combination. When performing surface treatment of the toner particles using the external additive, the addition amount of the external additive is preferably 1 part by mass or more, more preferably 2 parts by mass or more, still more preferably 3 parts by mass or more with respect to 100 parts by mass of the toner particles, and is preferably 5 parts by mass or less, more preferably 4.5 parts by mass or less, still more preferably 4 parts by mass or less.

[0141] [Toner for electrostatic charge image development] The toner for electrostatic charge image development obtained by the present invention can be used as a one-component developer or as a two-component developer by mixing with a carrier.

Examples

[0142] The present invention will be described in more detail below with reference to Examples and the like. Each property value was measured by the following method. Each type of evaluation was evaluated by the method shown below. [Measurement] [Acid value and hydroxyl value of resin and release agent] The acid value and hydroxyl value of the resin and release agent were measured according to the neutralization titration method described in JIS K 0070:1992. However, chloroform was used as the measurement solvent.

[0143] [Softening point, crystallinity index, melting point and glass transition temperature of resin] (1) Softening point Using a flow tester "CFT-500D" (manufactured by Shimadzu Corporation), while heating 1 g of the sample at a heating rate of 6 °C / min, a load of 1.96 MPa was applied by a plunger and extruded from a nozzle with a diameter of 1 mm and a length of 1 mm. The plunger drop amount of the flow tester was plotted against the temperature, and the temperature at which half of the sample flowed out was defined as the softening point.

[0144] (2) Crystallinity index Using a differential scanning calorimeter "Q100" (manufactured by TA Instruments Japan Co., Ltd.), 0.02 g of the sample was weighed into an aluminum pan and cooled from room temperature (20 °C) to 0 °C at a cooling rate of 10 °C / min. Then the sample was stopped as it was for 1 minute, and then heated from 0 °C to 180 °C at a heating rate of 10 °C / min to measure the heat quantity. Among the observed endothermic peaks, the temperature of the peak with the largest peak area was taken as the maximum endothermic peak temperature (1), and the crystallinity index was determined by (softening point (°C)) / (maximum endothermic peak temperature (1) (°C)).

[0145] (3) Melting point and glass transition temperature Using a differential scanning calorimeter "Q100" (manufactured by TA Instruments Japan Co., Ltd.), 0.02 g of the sample was weighed into an aluminum pan, heated up to 200°C, and then cooled from that temperature to 0°C at a cooling rate of 10°C / min. Subsequently, the sample was heated up at a heating rate of 10°C / min, and the heat quantity was measured. Among the observed endothermic peaks, the temperature of the peak with the largest peak area was defined as the maximum endothermic peak temperature (2). In the case of a crystalline resin, this peak temperature was regarded as the melting point. Also, in the case of an amorphous resin, when a peak was observed, the temperature of that peak was taken as the glass transition temperature. When no peak was observed but a step was observed, the temperature at the intersection of the tangent line showing the maximum slope of the curve at the step portion and the extension of the baseline on the low-temperature side of the step was defined as the glass transition temperature.

[0146] 〔Weight-average molecular weight of the addition polymer〕 Using a solution in which phosphoric acid and lithium bromide were dissolved in N,N-dimethylformamide at concentrations of 60 mmol / L and 50 mmol / L, respectively, as the eluent, gel permeation chromatography [GPC apparatus "HLC-8320GPC" (manufactured by Tosoh Corporation), columns "TSKgel SuperAWM-H", "TSKgel SuperAW3000", "TSKgel guardcolumn Super AW-H" (manufactured by Tosoh Corporation), flow rate: 0.5 mL / min], a monodisperse polystyrene kit with known molecular weights [PStQuick B (F-550, F-80, F-10, F-1, A-1000), PStQuick C (F-288, F-40, F-4, A-5000, A-500), manufactured by Tosoh Corporation] was used as the standard substance for measurement.

[0147] 〔Melting point of the release agent〕 Using a differential scanning calorimeter "Q100" (manufactured by TA Instruments Japan Co., Ltd.), 0.02 g of the sample was weighed into an aluminum pan, heated up to 200°C, and then cooled from 200°C to 0°C at a cooling rate of 10°C / min. Subsequently, the sample was heated up at a heating rate of 10°C / min, the heat quantity was measured, and the maximum endothermic peak temperature was regarded as the melting point.

[0148] [Volume median particle diameter (D 50 ) and CV value of resin particles, colorant particles, and mold release agent particles] (1) Measuring device: Laser diffraction particle size analyzer "LA-920" (manufactured by Horiba, Ltd.) (2) Measurement conditions: A sample dispersion was placed in a measurement cell, distilled water was added, and the volume median particle diameter (D 50 ) and volume average particle diameter were measured at a concentration that brought the absorbance within an appropriate range. The relative refractive index was set to 1.10, the circulation pump was turned on, and the circulation speed was set to 5. The CV value was calculated according to the following formula. CV value (%) = (standard deviation of particle size distribution / volume average particle diameter) × 100

[0149] [Solid content concentration of resin particle dispersion, colorant particle dispersion, and mold release agent particle dispersion] Using an infrared moisture meter "FD-230" (manufactured by Kett Science Laboratory Co., Ltd.), 5 g of the measurement sample was measured for moisture (mass %) at a drying temperature of 150 °C and a measurement mode of 96 (monitoring time 2.5 minutes, fluctuation range of moisture content 0.05%). The solid content concentration was calculated according to the following formula. Solid content concentration (mass %) = 100 - moisture (mass %)

[0150] [Volume median particle diameter (D 50 ) and CV value of aggregated particles and fused particles] (1) Measuring device: "Coulter Multisizer (registered trademark) III" (manufactured by Beckman Coulter, Inc.) (2) Analysis software: "Multisizer (registered trademark) III version 3.51" (manufactured by Beckman Coulter, Inc.) (3) Measurement conditions: · Electrolyte: "Isoton (registered trademark) III" (manufactured by Beckman Coulter, Inc.) · Aperture diameter: 50 μm The sample dispersion was added to 100 mL of the above electrolyte, adjusted to a concentration at which the particle sizes of 30,000 particles could be measured in 20 seconds, and then 30,000 particles were measured again. The volume median particle diameter (D 50 ) was determined from the particle size distribution. CV value (%) = (standard deviation of particle size distribution / volume average particle diameter) × 100

[0151] [pH in aqueous medium] Using a pH meter "SevenGo pH meter SG2" (manufactured by Mettler Toledo), connecting "InLab Expert Go" (manufactured by Mettler Toledo) as the electrode, and immersing the electrode of the pH meter in the aqueous medium, the pH was measured at each temperature with stirring.

[0152] [Circularity of fused particles] The circularity of the fused particles was measured under the following conditions. · Measuring device: Flow-type particle image analyzer "FPIA-3000" (manufactured by Sysmex Corporation) · Preparation of dispersion: The dispersion of the fused particles was diluted with deionized water so that the solid content concentration was 0.001 mass% or more and 0.05 mass% or less and then measured. · Measurement mode: HPF measurement mode

[0153] [Coarse particle ratio] The dispersion of the fused particles was passed through a 300-mesh (aperture 45 μm) sieve, the residue on the sieve was washed with deionized water, and then vacuum dried at 33 °C for 48 hours to obtain coarse particles. From the mass of the obtained coarse particles, the coarse particle ratio was calculated according to the following formula. The toner particle mass is the mass of the toner particles obtained after suction filtration of the dispersion passed through the sieve to separate the solid content, followed by deionized water washing and drying steps. Coarse particle ratio (%) = Coarse particle mass (g) / (Toner particle mass (g) + Coarse particle mass (g)) × 100

[0154] [Manufacture of resin] Production Example A1 (Production of amorphous resin A-1) The interior of a 10 L four-necked flask equipped with a nitrogen inlet tube, a water removal tube, a stirrer, and a thermocouple was purged with nitrogen. 3253 g of a propylene oxide (2.2) adduct of bisphenol A, 1003 g of terephthalic acid, 24 g of tin(II) bis(2-ethylhexanoate), and 2.4 g of 3,4,5-trihydroxybenzoic acid were added. While stirring under a nitrogen atmosphere, the temperature was raised to 235 °C and held at 235 °C for 5 hours. Then, the pressure inside the flask was reduced and held at 8 kPa for 1 hour. After that, after returning to atmospheric pressure, it was cooled to 160 °C and held at 160 °C. A mixture of 2139 g of styrene, 535 g of stearyl methacrylate, 107 g of acrylic acid, and 321 g of dibutyl peroxide was added dropwise over 1 hour. Then, after holding at 160 °C for 30 minutes, the temperature was raised to 200 °C, and the pressure inside the flask was further reduced and held at 8 kPa for 1 hour. After that, after returning to atmospheric pressure, it was cooled to 190 °C, 129 g of fumaric acid, 94 g of sebacic acid, 214 g of trimellitic anhydride, and 2.4 g of 4-tert-butylcatechol were added, the temperature was raised to 210 °C at 10 °C / hr, and then the reaction was carried out at 4 kPa until the desired softening point was reached to obtain an amorphous resin A-1. The physical properties are shown in Table 1.

[0155] Production Example B1 (Production of Resin B-1) The interior of a 10 L four-necked flask equipped with a nitrogen inlet tube, a water removal tube, a stirrer, and a thermocouple was purged with nitrogen. 3265 g of an ethylene oxide (2.2) adduct of bisphenol A, 1334 g of terephthalic acid, 25 g of tin(II) bis(2-ethylhexanoate), and 2.5 g of 3,4,5-trihydroxybenzoic acid were added. While stirring under a nitrogen atmosphere, the temperature was raised to 235 °C and held at 235 °C for 6 hours. Then, the pressure inside the flask was reduced and held at 8.3 kPa for 1 hour. After that, after returning to atmospheric pressure, it was cooled to 180 °C, 73 g of adipic acid, 135 g of dodecenyl succinic anhydride, and 193 g of trimellitic anhydride were added, the temperature was raised to 220 °C at 10 °C / hr, and then the pressure inside the flask was reduced and the reaction was carried out at 10 kPa until the desired softening point was reached to obtain an amorphous resin B-1. Various physical properties of the resin were measured and are shown in Table 1. Various physical properties of the resin were measured and are shown in Table 1.

[0156] Production Example D1 (Production of Resin D-1) Resin D-1 was obtained in the same manner as in Production Example A1, except that the raw material composition was changed as shown in Table 1. The physical properties are shown in Table 1.

[0157]

Table 1

[0158] Production Example C1 (Production of Crystalline Resin C-1) The inside of a 10 L four-necked flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple was purged with nitrogen. 3416 g of 1,10-decanediol and 4084 g of sebacic acid were added, and the temperature was raised to 135 °C with stirring. After holding at 135 °C for 3 hours, the temperature was raised from 135 °C to 200 °C over 10 hours. Then, 23 g of tin(II) bis(2-ethylhexanoate) was added, and after holding at 200 °C for 1 hour, the pressure inside the flask was reduced, and it was held under a reduced pressure of 8 kPa for 1 hour to obtain crystalline resin C-1. The physical properties are shown in Table 2.

[0159]

Table 2

[0160] [Production of Resin Particle Dispersion] Production Example X1 (Production of Resin Particle Dispersion X-1) Into a 3 L reaction vessel equipped with a stirrer, a reflux condenser, a dropping funnel, a thermometer, and a nitrogen inlet tube, 210 g of amorphous resin A-1, 90 g of crystalline resin C-1, and 360 g of methyl ethyl ketone were added, and the mixture was stirred at 73 °C for 2 hours to dissolve the resin. To the resulting solution, a 5 mass% aqueous sodium hydroxide solution was added to a neutralization degree of 50 mol% with respect to the acid value of the resin, and the mixture was stirred for 30 minutes. Next, while maintaining the temperature at 73°C and stirring at 280 r / min (peripheral speed 88 m / min), 600 g of deionized water was added over 60 minutes to cause phase inversion emulsification. Subsequently, while maintaining the temperature at 73°C, methyl ethyl ketone was distilled off under reduced pressure to obtain an aqueous dispersion. Thereafter, while stirring at 280 r / min (peripheral speed 88 m / min), the aqueous dispersion was cooled to 30°C, deionized water was added so that the solid content concentration became 30% by mass, and then it was filtered through a 150-mesh wire net to obtain a resin particle dispersion X-1. The volume median diameter (D 50 ) and CV value of the obtained resin particles are shown in Table 3.

[0161] Production Example Y1 (Production of Resin Particle Dispersion Y-1) 300 g of amorphous resin B-1 and 360 g of methyl ethyl ketone were placed in a 3-L reaction vessel equipped with a stirrer, a reflux condenser, a dropping funnel, a thermometer, and a nitrogen inlet tube, and the resin was dissolved at 40°C over 2 hours. To the obtained solution, a 5% by mass aqueous sodium hydroxide solution was added so that the degree of neutralization became 60 mol% with respect to the acid value of amorphous resin B-1, and it was stirred for 30 minutes. Next, while maintaining the temperature at 40°C and stirring at 280 r / min (peripheral speed 88 m / min), 600 g of deionized water was added over 60 minutes to cause phase inversion emulsification. The temperature was raised to 73°C, and methyl ethyl ketone was distilled off under reduced pressure to obtain an aqueous dispersion. Thereafter, while stirring at 280 r / min (peripheral speed 88 m / min), the aqueous dispersion was cooled to 30°C, deionized water was added so that the solid content concentration became 30% by mass, and then it was filtered through a 150-mesh wire net to obtain a resin particle dispersion Y-1. The volume median diameter (D 50 ) and CV value of the obtained resin particles are shown in Table 3.

[0162]

Table 3

[0163] Production Example Z1 (Production of Resin Particle Dispersion Z-1) Into a 3 L reaction vessel equipped with a stirrer, a reflux condenser, a dropping funnel, a thermometer, and a nitrogen inlet tube, 200 g of resin D-1 and 200 g of methyl ethyl ketone were placed, and the resin was dissolved at 73 °C over 2 hours. To the resulting solution, a 5 mass% aqueous sodium hydroxide solution was added to a neutralization degree of 60 mol% with respect to the acid value of the amorphous resin D-1, and the mixture was stirred for 30 minutes. Next, while maintaining the temperature at 73 °C, 700 g of deionized water was added over 50 minutes with stirring at 280 r / min (peripheral speed 88 m / min) to effect phase inversion emulsification. Subsequently, while maintaining the temperature at 73 °C, methyl ethyl ketone was distilled off under reduced pressure to obtain an aqueous dispersion. Thereafter, while stirring at 280 r / min (peripheral speed 88 m / min), the aqueous dispersion was cooled to 30 °C, deionized water was added so that the solid content concentration became 20 mass%, and then the mixture was filtered through a 150-mesh wire net to obtain a resin particle dispersion Z-1. The volume median diameter (D 50 ) of the obtained resin particles was 0.09 μm and the CV value was 23%.

[0164] [Production of Release Agent Particle Dispersion] Production Example W1 (Production of Release Agent Particle Dispersion W-1) To a 1 L beaker, 120 g of deionized water, 86 g of resin particle dispersion Z-1, and 40 g of paraffin wax "HNP-9" (manufactured by Nippon Seiro Co., Ltd., melting point 75 °C) were added, and the temperature was maintained at 90 - 95 °C to melt and stir to obtain a molten mixture. While maintaining the temperature of the obtained molten mixture at 90 - 95 °C, it was dispersed using an ultrasonic homogenizer "US-600T" (manufactured by Nippon Seiki Co., Ltd.) for 20 minutes and then cooled to room temperature (20 °C). Deionized water was added to adjust the solid content concentration to 20 mass% to obtain a release agent particle dispersion W-1. The volume median diameter D 50 and CV value of the release agent particles in the dispersion are shown in Table 4.

[0165] Production Example W2 (Production of Release Agent Particle Dispersion W-2) The release agent particle dispersion W-2 was obtained in the same manner as in Production Example W1, except that the type of release agent used was changed to Fischer-Tropsch wax "FNP-0090" (manufactured by Nippon Seiro Co., Ltd., melting point 90°C). The volume median diameter D of the release agent particles in the dispersion 50 and the CV value are shown in Table 4.

[0166] [Table 4]

[0167] [Production of addition polymer] Production Example E1 (Synthesis of addition polymer E-1) 16 g of methacrylic acid (manufactured by Fujifilm Wako Pure Chemical Corporation), 44 g of styrene (manufactured by Fujifilm Wako Pure Chemical Corporation), 30 g of styrene macromonomer "AS-6S" (manufactured by Toagosei Co., Ltd., number average molecular weight 6,000, solid content 50%) (15 g as solid content), and 25 g of methoxypolyethylene glycol methacrylate "Blemmer PME-200" (manufactured by NOF Corporation) were mixed to prepare 115 g of a monomer mixture. Into a reaction vessel, 18 g of methyl ethyl ketone, 0.03 g of 2-mercaptoethanol as a chain transfer agent, and 10% (11.5 g) of the monomer mixture were put and mixed, and sufficient nitrogen gas substitution was performed. On the other hand, the remaining 90% (103.5 g) of the monomer mixture, 0.27 g of the chain transfer agent, 42 g of methyl ethyl ketone, and 3 g of a polymerization initiator 2,2'-azobis(2,4-dimethylvaleronitrile) "V-65" (manufactured by Fujifilm Wako Pure Chemical Corporation) were mixed, and the resulting mixture was placed in a dropping funnel. While stirring the mixed solution in the reaction vessel under a nitrogen atmosphere, the temperature was raised to 75°C, and the mixed solution in the dropping funnel was dropped over 3 hours. After 2 hours had elapsed at 75°C from the end of dropping, a solution prepared by dissolving 3 g of the polymerization initiator in 5 g of methyl ethyl ketone was added, and the mixture was further aged at 75°C for 2 hours and at 80°C for 2 hours. Thereafter, methyl ethyl ketone was distilled off under reduced pressure to obtain addition polymer E-1. The weight average molecular weight of the obtained addition polymer is shown in Table 5.

[0168] [Table 5]

[0169] [Production of Colorant Particle Dispersion Liquid] Production Example F1 (Production of Colorant Particle Dispersion Liquid F-1) In a 5 L container equipped with a stirrer with a dispersing blade, a reflux condenser, a dropping funnel, a thermometer, and a nitrogen inlet tube, 75 g of the addition polymer E-1 was dissolved in 620 g of methyl ethyl ketone. Then, 96 g of a 5% by mass aqueous sodium hydroxide solution as a neutralizing agent and 942 g of deionized water were added, and the mixture was stirred at 20 °C for 10 minutes with a dispersing blade. Thereafter, 300 g of a copper phthalocyanine pigment "ECB-301" (manufactured by Dainichi Seika Kogyo Co., Ltd.) was added, and the mixture was stirred at 20 °C at 6400 r / min for 2 hours with a dispersing blade. Then, it was passed through a 200-mesh filter and treated for 15 passes at a pressure of 150 MPa using a homogenizer "Microfluidizer M-110EH" (manufactured by Microfluidics). While stirring the obtained dispersion liquid, methyl ethyl ketone and a part of water were removed at 70 °C under reduced pressure. Then, it was passed through a 200-mesh filter, and deionized water was added so that the solid content concentration became 20% by mass to obtain a colorant particle dispersion liquid F-1. The volume median diameter (D 50 ) of the colorant particles in the dispersion liquid was 0.12 μm, and the CV value was 21%.

[0170] [Production of Resin Particles for Toner] Example 1 (Production of Resin Particles for Toner 1) [Step 1] A 3L (inner volume) 10% bottom-diameter cylindrical tank (inner diameter 0.16m) equipped with a stirrer, a stirring blade (supermix blade (MR205 type, blade diameter 0.1m)), a dropping funnel, and a thermocouple was charged with 360g of resin particle dispersion X-1, 56g of mold release agent particle dispersion W-1, 56g of mold release agent particle dispersion W-2, 105g of colorant particle dispersion F-1, and 290g of deionized water, and they were mixed at 25°C. Next, while stirring the mixture at a stirring rotation speed of 200 r / min, an aqueous solution prepared by dissolving 50g of ammonium sulfate in 586g of deionized water and adding 63g of a 4.8 mass% potassium hydroxide aqueous solution to adjust the pH to 8.8 was added dropwise at 25°C over 30 minutes. Then, the temperature was raised to 62°C over 2 hours and held at 62°C until the volume median diameter D 50 of the aggregated particles became 6.5μm, and a dispersion of the aggregated particles (1) was prepared. The total amount of the dispersion of the aggregated particles (1) in Step 1 was 1566g, and the solid content concentration of the aggregated particles (1) was 9.7%. [Step 2] The dispersion of the aggregated particles (1) was cooled to 56°C, and while holding at 56°C, a mixed solution of 54g of resin particle dispersion Y-1 and 16g of deionized water was added dropwise over 1 hour to prepare a dispersion of aggregated particles (2) in which resin particles Y were aggregated to the aggregated particles (1). The volume median diameter D 50 of the obtained aggregated particles (2) was 6.7μm. The total amount of the dispersion of the aggregated particles (2) in Step 2 was 1636g, and the solid content concentration of the aggregated particles (2) was 10.3%. [Step 3] To the dispersion of the aggregated particles (2), an aqueous solution prepared by dissolving 6.2 g of the sodium salt of a special β-naphthalenesulfonic acid formalin condensate "Demol SN-B" (manufactured by Kao Corporation), which is an amphiphilic molecule, in 34.4 g of deionized water was added. Then, after raising the temperature to 75°C over 1 hour, 90 g of 0.1 mol / L sulfuric acid was added, and it was maintained at 75°C until the circularity reached 0.970 to prepare a dispersion of fused particles (3) in which the aggregated particles (2) were fused. The pH before adding sulfuric acid was 7.1, and the pH after adding sulfuric acid was 6.9. The addition amount of sulfuric acid was 2.4 times the molar equivalent of the acid groups (carboxy groups) possessed by the resin particles Y. Since the total amount of the dispersion in Step 3 was 1766.6 g and the solid content of the aggregated particles (2) was 168.4 g, the solid content concentration of the aggregated particles (2) in Step 3 was 9.5%.

[0171] (Cooling Step) 4.0 kg of deionized water was placed in a container with an internal volume of 20 liters and cooled to 7.7°C. While stirring the cooled deionized water, 1780 g of the dispersion of the fused particles (3) fused at 75°C was added to the cooled deionized water within 10 seconds, and stirred to cool the dispersion of the fused particles (3) to 27°C. The cooled dispersion of the fused particles (3) was passed through a 300-mesh sieve (pore diameter 45 μm) to obtain a dispersion of the fused particles (4). The physical properties of the fused particles (4) are shown in Table 6. Also, after washing the residue on the mesh with deionized water, it was vacuum dried at 33°C for 48 hours to obtain coarse particles (5).

[0172] (Filtration and Drying Step) The dispersion of the fused particles (4) filtered through the mesh was suction filtered to separate the solid content, then washed with deionized water at 25°C and suction filtered at 25°C for 2 hours. Then, using a vacuum low-temperature dryer (DRV622DA manufactured by ADVANTEC), vacuum drying was performed at 33°C for 48 hours to prepare toner particles (6). Table 6 shows the results of calculating the coarse particle ratio from the mass of the above-mentioned coarse particles (5) and the mass of the toner particles (6).

[0173] Example 2 (Preparation of Toner Resin Particles 2) Toner resin particles 2 were prepared in the same manner as in Example 1, except that the amount of the amphiphilic molecule used in Step 3 was changed to 15.5 g and the amount of deionized water was changed to 25.1 g. The physical properties of the obtained fused particles and the coarse particle ratio are shown in Table 6.

[0174] Example 3 (Preparation of toner resin particles 3) Toner resin particles 3 were prepared in the same manner as in Example 1, except that the amount of the amphiphilic molecule used in Step 3 was changed to 3.1 g and the amount of deionized water was changed to 37.5 g. The physical properties of the obtained fused particles and the coarse particle ratio are shown in Table 6.

[0175] Example 4 (Preparation of toner resin particles 4) Toner resin particles 4 were prepared in the same manner as in Example 1, except that the amount of the amphiphilic molecule used in Step 3 was changed to 3.1 g, the amount of deionized water was changed to 37.5 g, and the sulfuric acid concentration was changed to 0.2 mol / L. The physical properties of the obtained fused particles and the coarse particle ratio are shown in Table 6. The addition amount of sulfuric acid was 4.8 times the molar equivalent of the acid groups (carboxy groups) possessed by the resin particles Y.

[0176] Example 5 (Preparation of toner resin particles 5) Toner resin particles 5 were prepared in the same manner as in Example 2, except that the amphiphilic molecule used in Step 3 was changed as shown in Table 6. The physical properties of the obtained fused particles and the coarse particle ratio are shown in Table 6.

[0177] Comparative Example 1 (Preparation of toner resin particles 6) The amphiphilic molecule used in Step 3 was changed as shown in Table 6. Since the charging agent was an aqueous solution with an effective concentration of 27% by mass, toner resin particles 6 were prepared in the same manner as in Example 1, except that 57.2 g of the aqueous solution was added without dissolution or dilution. The physical properties of the obtained fused particles and the coarse particle ratio are shown in Table 6.

[0178] Comparative Example 2 (Preparation of toner resin particles 7) Toner resin particles 7 were produced in the same manner as in Example 5, except that sulfuric acid was not added in Step 3. The physical properties of the obtained fused particles and the coarse particle ratio are shown in Table 6.

[0179]

Table 6

[0180] As described above, from the results of the examples and comparative examples, according to the present invention, even when the solid content concentration of the aggregated particles in Step 3 is high, fused particles with excellent roundness of the fused particles and a low coarse particle ratio can be obtained.

Claims

1. including the following step 1 and step 3 in this order, or including the following steps 1 to 3 in this order, Step 1: A step of aggregating resin particles X in an aqueous medium to obtain aggregated particles 1, Step 2: A step of aggregating resin particles Y with respect to the aggregated particles 1 obtained in Step 1 to obtain aggregated particles 2, Step 3: A step of heating and fusing the aggregated particles 1 obtained in Step 1 or the aggregated particles 2 obtained in Step 2 to obtain fused particles, In Step 3, an amphiphilic molecule having a naphthalene ring and an acidic substance are added, A method for producing a toner for electrostatic charge image development.

2. In Step 3, the solid content concentration of the aggregated particles 1 or the aggregated particles 2 is 7% by mass or more. The method for producing a toner for electrostatic charge image development according to Claim 1.

3. The circularity of the fused particles is 0.955 or more. The method for producing a toner for electrostatic charge image development according to Claim 1 or 2.

4. The addition amount of the amphiphilic molecule having a naphthalene ring in Step 3 is 1 part by mass or more with respect to 100 parts by mass of the aggregated particles 1 or the aggregated particles 2. The method for producing a toner for electrostatic charge image development according to any one of Claims 1 to 3.

5. The amphiphilic molecule having a naphthalene ring is a formaldehyde condensate of unsubstituted or substituted naphthalenesulfonate. The method for producing a toner for electrostatic charge image development according to any one of Claims 1 to 4.

6. The resin particles Y contain a polyester resin B having an aromatic ring. The method for producing a toner for electrostatic charge image development according to any one of Claims 1 to 5.

7. The resin particles X contain an amorphous polyester resin A. The method for producing a toner for electrostatic charge image development according to any one of Claims 1 to 6.

8. The method for producing an electrostatic charge image developing toner according to any one of claims 1 to 7, wherein the resin particles X contain a crystalline polyester resin C.

9. The method for producing an electrostatic charge image developing toner according to any one of claims 1 to 8, wherein in step 3, the pH of the aqueous medium after adding the acidic substance is 5.0 or more and 7.0 or less.

10. The method for producing an electrostatic charge image developing toner according to any one of claims 1 to 9, wherein in step 3, an acidic substance is added to lower the pH of the aqueous medium by 0.1 or more and 2.0 or less.

11. The method for producing an electrostatic charge image developing toner according to any one of claims 1 to 10, wherein in step 3, an amphiphilic molecule having a naphthalene ring is added, and then the temperature is raised to cause fusion.

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