Toner for developing electrostatic charge image and method for manufacturing the same

Abstract

To provide a toner for developing an electrostatic charge image with high durability and a method for manufacturing the toner.SOLUTION: A toner for developing an electrostatic charge image is formed by attaching an external additive to toner particles, the toner particles containing a polyester resin A as a polycondensation material of an alcohol component (a) containing aliphatic diol (a1) in the concentration of at least 80 mol% and a carboxylic acid component (b), and the BET specific surface area [m2 / g] of the toner particles satisfying the following formula (1): 0.026x2-0.46x+2.70≤BET specific area≤0.026x2-0.46x+4.00 Formula (1) (x denotes the volume intermediate diameter D50[μm] of toner particles and 4≤x≤10 is satisfied.)SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an electrostatic charge image developing toner used for developing a latent image formed in an electrophotographic method, an electrostatic recording method, an electrostatic printing method, etc., and a method for manufacturing the same.

Background Art

[0002] In the field of electrophotography, with the development of electrophotographic systems, the development of electrophotographic toners corresponding to high image quality and high speed has been demanded. As a method for obtaining a toner with a narrow particle size distribution, small particle size, and fixability capable of corresponding to high speed in response to high image quality, fine resin particles or the like are aggregated and fused in an aqueous medium to obtain a toner. The so-called chemical toner is manufactured by an aggregation fusion method (emulsion aggregation method, aggregate unification method).

[0003] Patent Document 1 aims to provide a toner that has no residual hydrophobic organic solvent, has high productivity in small particle size toners, is excellent in moisture resistance, and has high low temperature fixability and hot offset resistance. A capsule toner is described in which resin particles (B) containing a resin having a carboxylate in the side chain are aggregated and coated on colored resin particles (A) containing at least a colorant, and the carboxylate in the side chain of the resin particles (B) is converted to a carboxylic acid.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Although it is widely practiced to improve the durability of toner by attaching external additives such as inorganic particles to toner particles, there is a problem that the action of the external additive is not achieved due to the detachment of the external additive from the toner particles or the embedding of the external additive into the toner particles, and streaks are likely to occur in the obtained image when printing for a long time. The present invention relates to an electrostatic charge image developing toner having excellent durability and suppressing the occurrence of streaks even when printed for a long time, and a method for manufacturing the same.

Means for Solving the Problems

[0006] The inventors of the present invention have found that by attaching an external additive to toner particles containing a polyester resin having a specific structure and having a volume median diameter D 50 and a BET specific surface area in a specific range, an electrostatic charge image developing toner having excellent durability can be obtained. The present invention relates to the following [1] and [2]. [1] An electrostatic charge image developing toner in which an external additive is attached to toner particles, wherein the toner particles contain a polyester resin A which is a polycondensate of an alcohol component (a) containing 80 mol% or more of an aliphatic diol (a1) and a carboxylic acid component (b), The BET specific surface area of the toner particles [m 2 / g] satisfies the following formula (1), an electrostatic charge image developing toner. 0.026x 2 -0.46x + 2.70 ≦ BET specific surface area ≦ 0.026x 2 -0.46x + 4.00 ··· Formula (1) (However, x is the volume median diameter D of the toner particles 50 [μm], and 4 ≦ x ≦ 10.) [2] A method for manufacturing an electrostatic charge image developing toner having the following steps 1 to 3, Step 1: A step of aggregating resin particles in an aqueous medium Step 2: A step of fusing the aggregated particles obtained in Step 1 Step 3: A step of mixing the toner particles obtained in Step 2 and an external additive The toner particles contain a polyester resin A which is a polycondensate of an alcohol component (a) containing 80 mol% or more of an aliphatic diol (a1) and a carboxylic acid component (b). The BET specific surface area of the toner particles [m 2 / g] satisfies the following formula (1), and a method for producing an electrostatic charge image developing toner. 0.026x 2 -0.46x + 2.70 ≤ BET specific surface area ≤ 0.026x 2 -0.46x + 4.00 ··· Formula (1) (However, x is the volume median particle diameter D of the toner particles 50 [μm], and 4 ≤ x ≤ 10.)

Advantages of the Invention

[0007] According to the present invention, an electrostatic charge image developing toner excellent in durability and a method for producing the same are provided.

Modes for Carrying Out the Invention

[0008] [Electrostatic Charge Image Developing Toner] In the electrostatic charge image developing toner of the present invention (hereinafter, also simply referred to as "toner"), an external additive adheres to the toner particles. The toner particles contain a polyester resin A which is a polycondensate of an alcohol component (a) containing 80 mol% or more of an aliphatic diol (a1) and a carboxylic acid component (b), and the BET specific surface area satisfies the following formula (1). 0.026x 2 -0.46x + 2.70 ≤ BET specific surface area ≤ 0.026x 2 -0.46x + 4.00 ··· Formula (1) (However, x is the volume median particle diameter D of the toner particles 50 [μm], and 4 ≤ x ≤ 10.) Due to the above characteristics, the electrostatic charge image developing toner of the present invention is excellent in durability.

[0009] The mechanism by which the toner of the present invention is excellent in durability is not clear, but it is considered as follows. The toner of the present invention contains a polyester resin A which is a polycondensate of an alcohol component (a) containing 80 mol% or more of an aliphatic diol (a1) and a carboxylic acid component (b). Since the polyester resin A contains many ester groups, it has high polarity, and the adhesion of external additives to toner particles is improved. Furthermore, by setting the volume median particle diameter D 50 within a specific range and controlling the BET specific surface area to satisfy the formula (1), the toner particles have very fine irregularities on the surface, and due to these irregularities, the contact points between the external additives and the toner particles are appropriately increased, so that the adhesion of the external additives to the toner particles is increased, and the external additives are not buried in the toner particles and can exist on the surface of the toner particles. As a result, the durability of the toner is improved, and it is considered that streakiness can be suppressed even when printing for a long time using the toner, and a high-quality image can be obtained. Note that the above mechanism regarding the effects of the present invention is an estimation, and the present invention is not limited thereto.

[0010] The definitions of various terms in this specification are shown below. 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 carboxylic acids, and alkyl esters (alkyl groups having 1 to 3 carbon atoms) of each carboxylic acid. 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 (softening point (°C) / maximum peak temperature of endotherm (°C)) in the measurement method described in the examples below. A crystalline resin is one having a crystallinity index of 0.6 or more and 1.4 or less. An amorphous resin is one in which no endothermic peak is observed, or if observed, the crystallinity index is less than 0.6 or more than 1.4. The crystallinity index can be appropriately adjusted by the types and ratios of the raw material monomers, and production conditions such as reaction temperature, reaction time, and cooling rate.

[0011] 〔Toner particles〕 The toner of the present invention contains toner particles, and the toner particles contain a polyester resin A which is a polycondensate of an alcohol component (a) containing 80 mol% or more of an aliphatic diol (a1) and a carboxylic acid component (b). From the viewpoint of obtaining a toner with excellent durability, it is preferable that the toner particles have a core-shell structure. When the toner particles have a core-shell structure, it is preferable that the shell portion contains the polyester resin A, and it is more preferable that both the core portion and the shell portion contain the polyester resin A.

[0012] <Polyester resin A> Polyester resin A (hereinafter, also simply referred to as "resin A") is a polycondensate of an alcohol component (a) containing 80 mol% or more of an aliphatic diol (a1) and a carboxylic acid component (b). Polyester resin A may be 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. Polyester resin A may be amorphous or crystalline, but from the viewpoint of facilitating the control of various physical properties of the toner, it is preferably amorphous. Also, from the viewpoint of low-temperature fixability, the toner particles may contain a crystalline polyester resin, and as the crystalline polyester resin, a polycondensate of an alcohol component (a) containing 80 mol% or more of an aliphatic diol (a1) and a carboxylic acid component (b) is preferable.

[0013] The alcohol component (a) contains 80 mol% or more of an aliphatic diol (a1). The carbon number of the aliphatic diol (a1) is preferably 2 or more, and preferably 16 or less, more preferably 12 or less, still more preferably 8 or less, and still more preferably 5 or less. The aliphatic diol (a1) preferably contains an aliphatic diol having 2 to 5 carbon atoms. Examples of the aliphatic diol include α,ω-aliphatic diols such as 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, and aliphatic diols other than α,ω-aliphatic diols such as 1,2-propanediol, 2,3-butanediol, and neopentyl glycol. Among these, ethylene glycol, 1,2-propanediol, and neopentyl glycol are preferable, and ethylene glycol and neopentyl glycol are more preferable.

[0014] The amount of the aliphatic diol (a1) is 80 mol% or more, preferably 85 mol% or more, more preferably 90 mol% or more, still more preferably 95 mol% or more, and 100 mol% or less, preferably 100 mol% in the alcohol component.

[0015] From the viewpoint of obtaining a toner excellent in durability, the amount of the aliphatic diol having 2 to 5 carbon atoms in the alcohol component (a) is preferably 60 mol% or more, more preferably 70 mol% or more, still more preferably 80 mol% or more, still more preferably 90 mol% or more, and 100 mol% or less, preferably 100 mol%.

[0016] The alcohol component may contain other alcohol components different from the aliphatic diol. Examples of the other alcohol components include alkylene oxide adducts of aromatic diols such as alkylene oxide adducts of bisphenol A; and trihydric or higher alcohols such as glycerin, pentaerythritol, and trimethylolpropane. One or more of the alcohol components may be used.

[0017] Examples of the carboxylic acid component include dicarboxylic acids and polyvalent carboxylic acids having a valence of 3 or more.

[0018] Examples of the dicarboxylic acid include aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and alicyclic dicarboxylic acids. Among these, aromatic dicarboxylic acids are preferred.

[0019] Examples of the aromatic dicarboxylic acid include phthalic acid, isophthalic acid, and terephthalic acid. Among these, isophthalic acid and terephthalic acid are preferred. The amount of the aromatic dicarboxylic acid is preferably 60 mol% or more, more preferably 70 mol% or more, still more preferably 80 mol% or more in the carboxylic acid component, and is preferably 100 mol% or less, preferably 100 mol%.

[0020] The number of carbon atoms of the aliphatic dicarboxylic acid is preferably 2 or more, more preferably 3 or more, and is preferably 30 or less, more preferably 20 or less. Examples of the 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. When the carboxylic acid component contains an aliphatic dicarboxylic acid, the amount of the aliphatic dicarboxylic acid is preferably 5 mol% or more, more preferably 10 mol% or more, still more preferably 15 mol% or more in the carboxylic acid component, and is preferably 40 mol% or less, more preferably 30 mol% or less, still more preferably 20 mol% or less.

[0021] Examples of the alicyclic dicarboxylic acid include cyclohexanedicarboxylic acid.

[0022] As the polyvalent carboxylic acid having a valence of 3 or more, a trivalent carboxylic acid is preferable, and examples thereof include trimellitic acid. One kind or two or more kinds of carboxylic acid components may be used.

[0023] 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.

[0024] <Production method of polyester resin A> Resin A is produced by a method of polycondensing an alcohol component (a) containing 80 mol% or more of an aliphatic diol (a1) and a carboxylic acid component (b). In this reaction, if necessary, an esterification catalyst such as tin(II) bis(2-ethylhexanoate), dibutyltin oxide, or titanium diisopropoxide bistriethanolamineate is 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; an esterification co-catalyst such as gallic acid (the same as 3,4,5-trihydroxybenzoic acid) is 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, and the reaction may be carried out. When using a monomer having an unsaturated bond such as fumaric acid in the polycondensation, a radical polymerization inhibitor is preferably 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, if necessary. Examples of the radical polymerization inhibitor include 4-tert-butylcatechol. The reaction temperature is preferably 120°C or higher, more preferably 150°C or higher, still more preferably 170°C or higher, and preferably 250°C or lower, more preferably 240°C or lower. The reaction may be carried out in an inert gas atmosphere.

[0025] <Physical properties of polyester resin A> The softening point of Resin A is preferably 70 °C or higher, more preferably 80 °C or higher, still more preferably 90 °C or higher, from the viewpoint of heat-resistant storage stability, and is preferably 130 °C or lower, more preferably 120 °C or lower, still more preferably 110 °C or lower, from the viewpoint of low-temperature fixability. The glass transition temperature of Resin A is preferably 30 °C or higher, more preferably 35 °C or higher, still more preferably 40 °C or higher, from the viewpoint of heat-resistant storage stability, and is preferably 80 °C or lower, more preferably 70 °C or lower, still more preferably 65 °C or lower, from the viewpoint of low-temperature fixability.

[0026] The acid value of Resin A is preferably 5 mgKOH / g or higher, more preferably 8 mgKOH / g or higher, still more preferably 10 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.

[0027] The ester group concentration of Resin A is preferably 5.0 mmol / g or higher, more preferably 5.5 mmol / g or higher, still more preferably 6.5 mmol / g or higher, still more preferably 7.5 mmol / g or higher, and is preferably 12.0 mmol / g or lower, more preferably 10.0 mmol / g or lower, from the viewpoint of production efficiency. Here, the ester group concentration of the polyester resin is calculated by the following formula.

[0028]

Number

[0029] The softening point, glass transition temperature, acid value, and ester group concentration of Resin A can be appropriately adjusted according to the types and amounts of raw material monomers used, as well as manufacturing conditions such as reaction temperature, reaction time, and cooling rate. In addition, the softening point, glass transition temperature, and acid value of Resin A are determined by the methods described in the examples. When using two or more types of Resin A in combination, it is preferable that at least one type is within the range of the above physical properties. Furthermore, it is more preferable that the values of the softening point, glass transition temperature, and acid value obtained as their mixture are each within the aforementioned ranges.

[0030] From the perspective of obtaining a toner with excellent durability, the content of Resin A in the toner particles is preferably 40% by mass or more, more preferably 50% by mass or more, still more preferably 60% by mass or more, and preferably 99% by mass or less, more preferably 95% by mass or less, still more preferably 90% by mass or less, and still more preferably 85% by mass or less. When the toner particles have a core-shell structure, from the perspective of obtaining a toner with excellent durability, the content of Resin A in the shell portion is preferably 60% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, still more preferably 90% by mass or more, and is 100% by mass or less, preferably 100% by mass.

[0031] When the toner particles contain a crystalline polyester resin, the mass ratio of the crystalline polyester resin to the amorphous polyester resin [crystalline polyester resin / amorphous polyester resin] is preferably 3 / 97 or more, more preferably 5 / 95 or more, still more preferably 7 / 93 or more, from the perspective of low-temperature fixability, and is preferably 50 / 50 or less, more preferably 40 / 60 or less, still more preferably 30 / 70 or less.

[0032] <Colorant> The toner particles preferably contain a colorant. As the colorant, all dyes, pigments, etc. that are 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. The content of the colorant in the toner particles is preferably 1% by mass or more, more preferably 3% by mass or more, still more preferably 5% by mass or more, and preferably 25% by mass or less, more preferably 20% by mass or less, still more preferably 15% by mass or less, and still more preferably 10% by mass or less.

[0033] <Release agent> The toner particles preferably contain a release agent. Examples of the release agent include polypropylene wax, polyethylene wax, ethylene-propylene copolymer wax; hydrocarbon waxes such as microcrystalline wax, paraffin wax, Fischer-Tropsch 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.

[0034] The melting point of the release agent is preferably 60°C or higher, more preferably 70°C or higher, and preferably 160°C or lower, more preferably 140°C or lower, still more preferably 120°C or lower, and still more preferably 100°C or lower. The content of the release agent in the toner particles is preferably 0.1% by mass or more, more preferably 1% by mass or more, still more preferably 3% by mass or more, and preferably 25% by mass or less, more preferably 20% by mass or less, still more preferably 15% by mass or less.

[0035] In addition, the toner particles may contain additives such as a charge control agent, magnetic powder, fluidity improver, conductivity adjuster, reinforcing fillers such as fibrous substances, antioxidant, anti-aging agent, and cleaning property improver.

[0036] 〔Physical properties of toner particles〕 In the toner of the present invention, the BET specific surface area [m 2 / g] of the toner particles satisfies the following formula (1). 0.026x 2 -0.46x + 2.70 ≤ BET specific surface area ≤ 0.026x 2 -0.46x + 4.00 ··· Formula (1) (However, x is the volume median particle diameter D 50 [μm] of the toner particles, and 4 ≤ x ≤ 10.)

[0037] "0.026x 2 -0.46x + 2.70" in Formula (1) is a theoretical formula for calculating the BET specific surface area assuming the toner particles are true spheres (BET specific surface area [m 2 / g] = 0.0258x 2 -0.4603x + 2.6676), and is derived from the viewpoint of forming very fine irregularities on the surface of the toner particles to improve the adhesion of the external additive to the toner particles. When the toner particles satisfy "0.026x 2 -0.46x + 2.70 ≤ BET specific surface area", the adhesion of the external additive to the toner particles is improved. "0.026x 2 -0.46x + 4.00" in Formula (1) is derived from the viewpoint of manufacturing based on the above theoretical formula.

[0038] From the viewpoint of obtaining a toner with excellent durability, Formula (1) is preferably the following formula (2), more preferably the following formula (3), and even more preferably the following formula (4). 0.026x 2 -0.46x + 2.70 ≤ BET specific surface area ≤ 0.026x 2 -0.46x + 3.50 ··· Formula (2) 0.026x 2-0.46x + 2.70 ≤ BET specific surface area ≤ 0.026x 2 -0.46x + 3.00 ··· Formula (3) 0.026x 2 -0.46x + 2.75 ≤ BET specific surface area ≤ 0.026x 2 -0.46x + 3.00 ··· Formula (4)

[0039] The volume median particle diameter D of the toner particles 50 is 4 μm or more and 10 μm or less from the viewpoint of obtaining a toner with excellent durability, preferably 10 μm or less, more preferably 9 μm or less, and still more preferably 8 μm or less.

[0040] The roundness of the toner particles is preferably 0.95 or more, more preferably 0.96 or more, and preferably 1.00 or less, more preferably 0.99 or less, and still more preferably 0.98 or less from the viewpoint of obtaining a toner with excellent durability. The BET specific surface area, volume median particle diameter D of the toner particles 50 and roundness can be measured by the method described in the examples.

[0041] <External additive> The toner of the present invention is obtained by adhering an external additive to the toner particles. Examples of the external additive include fine particles of inorganic materials such as hydrophobic silica, titanium oxide, alumina, cerium oxide, and carbon black, and polymer fine particles such as polycarbonate, polymethyl methacrylate, and silicone resin. Among these, hydrophobic silica is preferred. The external additive may be used alone or in combination of two or more. Also, two or more kinds of hydrophobic silica with different particle sizes may be used. The number average particle diameter of the primary particles of the external additive is preferably 6 nm or more, more preferably 9 nm or more, and still more preferably 12 nm or more, and preferably 50 nm or less, more preferably 47 nm or less, and still more preferably 44 nm or less from the viewpoint of obtaining a toner with excellent durability. The number average particle diameter of the primary particles of the external additive can be measured by the method described in the examples. The amount of the external additive attached is preferably 0.5 parts by mass or more, more preferably 0.8 parts by mass or more, still more preferably 1.1 parts by mass or more, and preferably 4.5 parts by mass or less, more preferably 4.0 parts by mass or less, still more preferably 3.5 parts by mass or less, based on 100 parts by mass of the toner particles.

[0042] [Method for producing toner for electrostatic charge image development] The method for producing a toner for electrostatic charge image development of the present invention (hereinafter, also simply referred to as "production method") has the following steps 1 to 3. Step 1: A step of aggregating resin particles in an aqueous medium Step 2: A step of fusing the aggregated particles obtained in Step 1 Step 3: A step of mixing the toner particles obtained in Step 2 and an external additive The resin particles contain a polyester resin A which is a polycondensate of an alcohol component (a) containing 80% by mass or more of an aliphatic diol (a1) and a carboxylic acid component (b). The BET specific surface area [m 2 / g] of the toner particles satisfies the following formula (1). 0.026x 2 -0.46x + 2.70 ≤ BET specific surface area ≤ 0.026x 2 -0.46x + 4.00 ··· Formula (1) (However, x is the volume median particle diameter D 50 [μm] of the toner particles, and 4 ≤ x ≤ 10.) In addition, the polyester resin A, the BET specific surface area of the toner particles, and the volume median particle diameter D 50 [μm], etc. in the method for producing a toner for electrostatic charge image development of the present invention are the same as those of the toner for electrostatic charge image development of the present invention, and thus the description thereof is omitted. 50 [μm], etc.

[0043] The aggregated particles obtained in Step 1 include aggregated particle 1 obtained by aggregating resin particles in an aqueous medium, and aggregated particle 2 obtained by using the aggregated particle 1 as a core and attaching and aggregating shell resin particles to this core in the aqueous medium. In this specification, when simply described as "aggregated particles", it means aggregated particle 1 or 2.

[0044] 〔Step 1: Step of aggregating resin particles in an aqueous medium〕 In Step 1, aggregated particle 1 is obtained by aggregating resin particles containing resin A in an aqueous medium. In Step 1, it is preferable to mix the resin particles, the colorant particles, and the mold release agent particles and aggregate these particles to obtain aggregated particle 1.

[0045] In the present invention, the aqueous medium used for the aqueous dispersion is a medium mainly composed of water, and 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 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 ethanol is more preferable.

[0046] <Method for producing resin particle dispersion> Dispersion can be carried out using a known method, but it is preferably carried out 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 for phase inversion emulsification. A method of adding an aqueous medium to an organic solvent solution of a resin for phase inversion emulsification is preferable. The organic solvent used for phase inversion emulsification dissolves the resin and is not particularly limited as long as it is water-soluble. For example, methyl ethyl ketone can be mentioned. A neutralizing agent may be added 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; nitrogen-containing basic substances such as ammonia, trimethylamine, and diethanolamine. Among these, hydroxides of alkali metals such as sodium hydroxide and potassium hydroxide are preferred. The degree of neutralization of the resin constituting the resin particles 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, 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 resin constituting the resin particles can be determined by the following formula. Degree of neutralization (mol%) = 〔{Mass of neutralizing agent added (g) / Equivalent of neutralizing agent} / [{Weight-average acid value of resin constituting resin particles (mgKOH / g) × Mass of resin constituting resin particles (g)} / (56 × 1000)]〕× 100

[0047] While stirring the organic solvent solution or the molten resin, an aqueous medium is gradually added to cause phase inversion. From the viewpoint of improving the dispersion stability of the resin particles, the temperature of the organic solvent solution when adding the aqueous medium is preferably at or above the glass transition temperature of resin A, for example, 60 °C or above, preferably 70 °C or above, and preferably 100 °C or below, more preferably 95 °C or below, still more preferably 90 °C or below.

[0048] After phase inversion emulsification, if necessary, the organic solvent may be removed from the obtained dispersion by distillation or the like. Also, the resin particles may be isolated by filtration or the like. It is preferable to use a resin particle dispersion liquid obtained by removing the organic solvent from the dispersion liquid obtained after phase inversion emulsification. In this case, the residual amount of the organic solvent in the dispersion liquid is preferably 1 mass% or less, more preferably 0.5 mass% or less, still more preferably substantially 0 mass%.

[0049] The volume median particle diameter D of the resin particles 50is preferably 0.08 μm or more, more preferably 0.12 μm or more, and is preferably 1 μm or less, more preferably 0.5 μm or less, and even more preferably 0.3 μm or less. The volume median diameter D of the resin particles 50 is measured by the method described in the examples.

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

[0051] <Method for producing a colorant particle dispersion> The colorant particles are preferably obtained by dispersing a colorant and an aqueous medium using a disperser such as a homogenizer or an ultrasonic disperser to obtain a colorant particle dispersion. From the viewpoint of improving the dispersion stability of the colorant, the dispersion is preferably carried out in the presence of a surfactant or an addition polymer (hereinafter, the addition polymer used for dispersing the colorant is also referred to as "addition polymer E"). Examples of the surfactant include nonionic surfactants, anionic surfactants, and cationic surfactants. The addition polymer E preferably has a structural unit derived from an addition polymerizable monomer a having an aromatic group, and further preferably contains at least one selected from the group consisting of an addition polymerizable monomer b having an ionic group, an addition polymerizable monomer c having a polyalkylene oxide group, and a macromonomer d. For the colorant particle dispersion using the addition polymer E, reference is made to JP-A-2021-026129 and JP-A-2024-25642.

[0052] The content of the colorant in the colorant particle dispersion is preferably 1% by mass or more, more preferably 3% by mass or more, still more preferably 5% 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, from the viewpoint of the image density of the printed matter. The solid content concentration of the release agent 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 40% by mass or less, more preferably 30% by mass or less.

[0053] The volume median diameter D of the colorant particles 50 is preferably 0.05 μm or more, more preferably 0.08 μm or more, and preferably 0.4 μm or less, more preferably 0.3 μm or less, still more preferably 0.25 μm or less, from the viewpoint of improving the dispersibility of the colorant in the toner. The volume median diameter D of the colorant particles 50 is measured by the method of the examples.

[0054] <Method for producing release agent particle dispersion> The release agent particles, as a release agent particle dispersion, can be obtained, for example, by dispersing a release agent, a resin particle dispersion, and, if necessary, an aqueous medium at a temperature equal to or higher than the melting point of the release agent using a dispersing machine such as a homogenizer, a high-pressure dispersing machine, or an ultrasonic dispersing machine. 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 100 °C or lower, more preferably 98 °C or lower, still more preferably 96 °C or lower.

[0055] Although it is also possible to obtain the release agent particle dispersion using a surfactant, it is preferable to obtain it by mixing the release agent and the resin particles. By preparing the release agent particles using the release agent and the resin particles, the release agent particles are stabilized by the resin particles, and it becomes possible to disperse the release agent in the aqueous medium without using a surfactant. In the release agent particle dispersion, it is considered to have a structure in which a large number of resin particles adhere to the surface of the release agent particles. The resin constituting the resin particles that disperse the release agent is preferably a polyester resin, and it is more preferable to use the aforementioned resin A.

[0056] The volume median diameter D of the release agent particles 50 is preferably 0.05 μm or more, more preferably 0.1 μm or more, still more preferably 0.15 μm or more, and preferably 1 μm or less, more preferably 0.8 μm or less, still more preferably 0.5 μm or less, from the viewpoint of obtaining uniform agglomerated particles 1 by aggregation. The volume median diameter D of the release agent particles 50 is measured by the method described in the examples.

[0057] (Surfactant) In step 1, when preparing the mixed dispersion by mixing the dispersions of the respective particles, it may be carried out in the presence of a surfactant from the viewpoint of improving the dispersion stability of the resin particles, release agent particles, colorant particles, etc. 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. When using a surfactant, the total amount used is preferably 0.1 part by mass or more, more preferably 0.3 part by mass or more, still 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, still more preferably 3 parts by mass or less, based on 100 parts by mass of the total amount of the binder resin in the agglomerated particles 1.

[0058] (Flocculant) In step 1, it is preferable to add a flocculant from the viewpoint of efficiently performing aggregation. Examples of the flocculant include cationic surfactants such as quaternary salts, organic flocculants such as polyethyleneimine, and inorganic flocculants. Examples of the inorganic flocculants include inorganic metal salts such as sodium sulfate, sodium nitrate, sodium chloride, calcium chloride, and calcium nitrate; inorganic ammonium salts such as ammonium sulfate, ammonium chloride, and ammonium nitrate; and divalent or higher metal complexes. From the viewpoint of improving the aggregability and obtaining uniform aggregated particles 1, an inorganic aggregating agent having a valence of 1 or more and 5 or less is preferable, an inorganic metal salt or inorganic ammonium salt having a valence of 1 or more and 2 or less is more preferable, an inorganic ammonium salt is still more preferable, and ammonium sulfate is still more preferable.

[0059] Using an aggregating agent, for example, in a mixed dispersion containing resin particles, release agent particles, and colorant particles at 0°C or higher and 40°C or lower, 25 parts by mass or more and 50 parts by mass or less of the aggregating agent is added based on 100 parts by mass in total of the binder resin in the aggregated particles 1, and the resin particles, release agent particles, and colorant particles are aggregated in an aqueous medium to obtain the aggregated particles 1. Further, from the viewpoint of promoting aggregation, it is preferable to raise the temperature of the dispersion after adding the aggregating agent.

[0060] Examples of the method for stopping aggregation include a method of cooling the dispersion, a method of adding an aggregation stopper, a method of diluting the dispersion, etc. From the viewpoint of surely preventing unnecessary aggregation, a method of adding an aggregation stopper to stop aggregation is preferable.

[0061] (Aggregation stopper) As the aggregation stopper, a surfactant is preferable, and an anionic surfactant is more preferable. Examples of the anionic surfactant include alkylbenzene sulfonate, alkyl sulfate, alkyl ether sulfate, polyoxyalkylene alkyl ether sulfate, aryl sulfonate, aryl sulfonic acid formalin condensate, etc., preferably an alkali metal salt of aryl sulfonic acid formalin condensate, more preferably a sodium salt of β-naphthalene sulfonic acid formalin condensate. These may be used alone or in combination of two or more. The aggregation stopper may be added in an aqueous solution. From the viewpoint of surely preventing unnecessary aggregation, the addition amount of the aggregation stopper is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, based on 100 parts by mass in total of the binder resin in the aggregated particles 1, and from the viewpoint of reducing the residue in the toner, it is preferably 45 parts by mass or less, more preferably 40 parts by mass or less, still more preferably 35 parts by mass or less.

[0062] The volume median diameter D of the aggregated particles 1 50 is preferably 4 μm or more, and preferably 10 μm or less, more preferably 8 μm or less.

[0063] In addition, in the production method of the present invention, from the viewpoint of obtaining a toner with excellent durability, after step 1 and before step 2, it is preferable to attach and aggregate shell resin particles to the obtained aggregated particles 1 to obtain aggregated particles 2. By aggregating the shell resin particles, toner particles having a core-shell structure can be obtained. The shell resin particles are preferably an amorphous resin, more preferably an amorphous polyester resin, and still more preferably the resin A described above. The shell resin particle dispersion is obtained by the same method as the method for producing the resin particle dispersion described above. In addition, when the toner production method has a step of aggregating shell resin particles, in this step, it is preferable to stop the aggregation when the aggregated particles 2 have grown to an appropriate particle size as toner particles, and a method of adding the above-mentioned aggregation inhibitor to stop the aggregation is preferable. The mass ratio of the shell resin particles to the mass of the aggregated particles 1 [shell resin particles / aggregated particles 1] is preferably 1 / 99 or more, more preferably 3 / 97 or more, still more preferably 5 / 95 or more, and preferably 25 / 75 or less, more preferably 20 / 80 or less, still more preferably 15 / 85 or less, from the viewpoint of obtaining a toner with excellent durability.

[0064] 〔Step 2: Step of fusing the aggregated particles obtained in Step 1〕 In step 2, for example, the aggregated particles obtained in step 1 are fused in an aqueous medium. By fusing, each particle contained in the aggregated particles is fused to obtain fused particles. In the step of fusing, from the viewpoint of improving the fusibility of the aggregated particles, it is held at a temperature equal to or higher than the glass transition temperature of the resin having the highest glass transition temperature among the resins contained in the aggregated particles. In addition, in the step of fusion bonding, a flocculation inhibitor can be used as a dispersant. From the viewpoint of improving the fusibility of the aggregated particles, the holding temperature when fusing the aggregated particles is preferably a temperature higher than the glass transition temperature of the resin having the highest glass transition temperature by 2°C or more, more preferably 3°C or more, still more preferably 5°C or more, and preferably a temperature lower than the glass transition temperature of the resin having the highest glass transition temperature by 30°C or less, more preferably 25°C or less, still more preferably 20°C or less. At that time, the holding time is preferably 1 minute or more, more preferably 10 minutes or more, still more preferably 30 minutes or more, and preferably 240 minutes or less, more preferably 180 minutes or less, still more preferably 120 minutes or less, and still more preferably 90 minutes or less, from the viewpoint of improving the low-temperature fixability of the toner. In addition, it is preferable to hold at the above temperature until a desired roundness is obtained.

[0065] The volume median diameter D of the fused particles obtained by fusion bonding 50 is preferably 4 μm or more, and preferably 10 μm or less, more preferably 8 μm or less.

[0066] The roundness of the fused particles obtained by fusion bonding is preferably 0.95 or more, more preferably 0.96 or more, and preferably 1.00 or less, more preferably 0.99 or less, still more preferably 0.98 or less. It is preferable that the fusion bonding is terminated after reaching the above preferable roundness. The roundness is measured by the method described in the examples.

[0067] 〔Washing step〕 From the viewpoint of efficiently controlling the BET specific surface area of the toner particles within a desired range, it is preferable to perform the following washing step after step 2 and before step 3. Washing step: A step of adding an acidic substance to the fused particle dispersion obtained in step 2, adjusting the pH of the fused particle dispersion to 3 or more and less than 11, and then washing with water

[0068] As the acidic substance, either an organic acid or an inorganic acid may be used, and an inorganic acid is preferred. Specific examples of the inorganic acid include hydrochloric acid, sulfuric acid, and nitric acid. The acidic substance may be used alone or in combination of two or more. The acidic substance may be added to the fused particle dispersion as an aqueous solution. The temperature of the acidic substance aqueous solution is, for example, 15°C or higher and 35°C or lower. The pH of the fused particle dispersion after adding the acidic substance is more preferably 9 or lower, still more preferably 7 or lower, and even more preferably 6 or lower. After adjusting the pH of the fused particle dispersion to 3 or higher and less than 11, since the fused particles are present in the aqueous medium, it is preferable to obtain toner particles by solid-liquid separation of the fused particles before washing with water. For solid-liquid separation, a suction filtration method or the like is preferably used. It is preferable to perform water washing after solid-liquid separation. At this time, since it is preferable to remove the added surfactant as well, it is preferable to wash with an aqueous medium below the cloud point of the surfactant. It is preferable to perform water washing a plurality of times. Next, it is preferable to perform drying. Examples of the drying method include a vacuum low-temperature drying method, a vibration-type fluidized drying method, a spray drying method, a freeze drying method, and a flash jet method. Note that toner particles may be obtained by solid-liquid separation, water washing, and drying of the fused particle dispersion obtained in Step 2 without performing "adding an acidic substance and adjusting the pH of the fused particle dispersion to 3 or higher and less than 11" in the "washing step".

[0069] 〔Step 3: Step of mixing the toner particles obtained in Step 2 and an external additive〕 The toner of the present invention is obtained by adding and treating an external additive on the surface of the toner particles obtained in Step 2 or the toner particles after the washing step. The addition treatment can be performed by mixing the toner particles obtained in Step 2 or the toner particles after the washing step and the external additive.

[0070] Toner is used for developing an electrostatic latent image in electrophotographic printing. The toner can be used, for example, as a one-component developer or as a two-component developer mixed with a carrier.

Examples

[0071] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples in any way. Each property value was measured and evaluated by the following methods. In notations such as “alkylene oxide (X)”, the numerical value X in parentheses means the average number of moles of alkylene oxide added.

[0072] [Measurement method] [Acid value of resin] The acid value of the resin was measured according to the neutralization titration method described in JIS K 0070:1992. However, the measurement solvent was a mixed solvent of acetone and toluene (acetone:toluene = 1:1 (volume ratio)).

[0073] [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 temperature rising 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 descent amount of the flow tester was plotted against the temperature, and the temperature at which half of the sample flowed out was taken as the softening point. (2) Crystallinity index Using a differential scanning calorimeter “Q100” (manufactured by TA Instruments Japan Co., Ltd.), 0.02 g of the sample was weighed into an aluminum pan and cooled to 0 ° C at a temperature decreasing rate of 10 ° C / min. Then, the temperature was held as it was for 1 minute, and then the temperature was raised to 180 ° C at a temperature rising 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)). (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 taken as the maximum endothermic peak temperature (2). In the case of a crystalline resin, this peak temperature was taken as the melting point. Also, when a peak was observed in the case of an amorphous resin, 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 line of the baseline on the low-temperature side of the step was taken as the glass transition temperature.

[0074] 〔Ester group concentration of resin〕 Calculated by the above formula.

[0075] 〔Melting point of 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 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, and the maximum endothermic peak temperature was taken as the melting point.

[0076] 〔Volume median diameter D of resin particles, release agent particles, and colorant particles〕 50 〕 (1) Measuring device: Laser diffraction particle size analyzer "LA-920" (manufactured by Horiba, Ltd.) (2) Measuring conditions: Distilled water was added to the measuring cell, and the volume median diameter D was measured at a concentration that made the absorbance fall within an appropriate range. 50 was measured.

[0077] 〔Solid content concentration of resin particle dispersion, release agent particle dispersion, and colorant particle dispersion〕 Using an infrared moisture meter "FD-230" (manufactured by Kett Scientific Laboratories 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 min / variation width 0.05%). The solid content concentration was calculated according to the following formula. Solid content concentration (mass%) = 100 - moisture (mass%)

[0078] 〔Volume median diameter D of aggregated particles 50 〕 · Measuring instrument: "Coulter Multisizer (registered trademark) III" (manufactured by Beckman Coulter, Inc.) · Aperture diameter: 50 μm · Analysis software: "Multisizer (registered trademark) III version 3.51" (manufactured by Beckman Coulter, Inc.) · Electrolyte: "Isoton (registered trademark) II" (manufactured by Beckman Coulter, Inc.) · Measurement conditions: By adding the sample dispersion to 100 mL of the above electrolyte, the concentration was 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, and the volume median diameter D 50 was determined from the particle size distribution.

[0079] 〔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 prepared by diluting with deionized water so that the solid content concentration was 0.001 to 0.05 mass%. · Measurement mode: HPF measurement mode

[0080] 〔Volume median diameter D of toner particles 50 〕 The measuring instrument, aperture diameter, analysis software, and electrolyte used were the same as those used in the measurement of the volume median diameter D 50 of the aggregated particles. · Dispersion: Polyoxyethylene lauryl ether "Emulgen (registered trademark) 109P" (manufactured by Kao Corporation, HLB (Hydrophile-Lipophile Balance): 13.6) was dissolved in the electrolyte to obtain a dispersion with a concentration of 5% by mass. · Dispersion conditions: 10 mg of the toner measurement sample was added to 5 mL of the dispersion, and it was dispersed with an ultrasonic disperser for 1 minute. Then, 25 mL of the electrolyte was added, and it was further dispersed with an ultrasonic disperser for 1 minute to prepare a sample dispersion. · Measurement conditions: By adding the sample dispersion to 100 mL of the electrolyte, after adjusting the concentration to a concentration at which the particle sizes of 30,000 particles can be measured in 20 seconds, 30,000 particles were measured, and the volume median particle size D 50 was determined.

[0081] 〔Circularity of toner particles〕 The circularity of the toner particles was measured under the following conditions. · Measuring device: Flow-type particle image analyzer "FPIA-3000" (manufactured by Sysmex Corporation) · Preparation of dispersion: A dispersion of toner particles was prepared by diluting with deionized water so that the solid content concentration was 0.001 to 0.05% by mass. · Measurement mode: HPF measurement mode

[0082] 〔BET specific surface area of toner particles〕 The specific surface area of the toner particles was obtained using the BET multipoint method with a specific surface area measuring device. In the BET multipoint method, the adsorption amount was measured at three or more points within the range where the equilibrium relative pressure of the adsorbed gas (nitrogen) was 0.05 to 0.30, and the specific surface area was calculated. Specifically, the analysis was carried out under the following measurement conditions. · Measuring instrument: Multi-sample high-performance specific surface area / pore size distribution measuring device 3Flex-3MP (manufactured by Micromeritics) · Dispersed adsorbate: Nitrogen · Pretreatment: 40 °C, 4 hours or more · Equilibrium relative pressure: 0.05 to 0.30 (every 0.05) · Equilibrium interval: 10 seconds

[0083] 〔Average particle diameter of primary particles of external additive〕 The average particle diameter refers to the number-average particle diameter. The particle diameters (average value of the major axis and minor axis) of 500 particles are measured from a scanning electron microscope (SEM) photograph, and their number-average value is used.

[0084] [Production of Polyester Resin] Production Example A1 (Production of Resin A-1) Neopentyl glycol, terephthalic acid, and an esterification catalyst shown in Table 1 were placed in a 10 L four-necked flask equipped with a thermometer, a stainless steel stirring rod, a dehydration tube, a cooling tube, and a nitrogen inlet tube. Under a nitrogen atmosphere, the temperature was raised to 180 °C in a mantle heater and reacted for 2 hours, and then the temperature was raised to 210 °C at a rate of 5 °C / h. After that, after cooling to 180 °C, isophthalic acid was added, the temperature was raised to 190 °C again, reacted for 1 hour, and then the temperature was raised to 220 °C at a rate of 10 °C / h. Then, the reaction was carried out at 13.3 kPa until the softening point shown in Table 1 was reached, and Resin A-1 was obtained. The physical property values of Resin A-1 are shown in Table 1.

[0085] Production Example A2 (Production of Resin A-2) The raw material monomers of the polyester resin other than isophthalic acid and an esterification catalyst shown in Table 1 were placed in a 10 L four-necked flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple. Under a nitrogen atmosphere, the reaction system was maintained at 205 °C for 1 hour, then the temperature was raised from 205 °C to 235 °C at 10 °C / h, and then held at 235 °C for 3 hours for polycondensation. After that, after cooling to 185 °C, isophthalic acid was added to the reaction system, the temperature was raised from 185 °C to 235 °C at 10 °C / h, reacted at 235 °C for 5 hours, and the reaction was carried out at 235 °C and 10 kPa until the softening point shown in Table 1 was reached, and Resin A-2 was obtained. The physical property values of Resin A-2 are shown in Table 1.

[0086] Production Example B1 (Production of Resin B-1) A 10-liter four-necked flask equipped with a thermometer, a stainless-steel stirring rod, a down-flow condenser having a dehydrating tube, and a nitrogen inlet tube was charged with an alcohol component, terephthalic acid, and an esterification catalyst as shown in Table 1. While stirring under a nitrogen atmosphere, the temperature was raised to 235 °C and held for 4 hours. Then, the pressure inside the flask was further reduced and held at 8 kPa for 1 hour. Thereafter, it was cooled to 210 °C and returned to atmospheric pressure. Then, fumaric acid, trimellitic anhydride, and 4-tert-butylcatechol were added and held at 210 °C for 3 hours. Then, the pressure inside the flask was further reduced and reacted at 8 kPa until the softening point shown in Table 1 was reached to obtain Resin B-1. The physical property values of the obtained Resin B-1 are shown in Table 1.

[0087]

Table 1

[0088] [Production of resin particle dispersion liquid] Production Example X1 (Production of resin particle dispersion liquid X-1) 1000 g of Resin A-1 and 1000 g of methyl ethyl ketone were placed in a 5 L container equipped with a stirrer, a reflux condenser, a dropping funnel, a thermometer, and a nitrogen inlet tube, and the resin was dissolved at 80 °C over 1 hour. To the obtained solution, a 5 mass% aqueous sodium hydroxide solution was added so that the degree of neutralization was 80 mol% with respect to the acid value of Resin A-1, and the mixture was stirred for 30 minutes. Next, while maintaining the temperature at 80 °C, 3000 g of deionized water was added over 60 minutes while stirring at 280 r / min (peripheral speed 88 m / min) to effect phase inversion emulsification. Subsequently, while maintaining the temperature at 80 °C, methyl ethyl ketone was distilled off under reduced pressure to obtain an aqueous dispersion of the resin. Thereafter, while stirring at 280 r / min (peripheral speed 88 m / min), the aqueous dispersion was cooled to 30 °C, and deionized water was added so that the solid content concentration became 25 mass% to obtain resin particle dispersion liquid X-1. The volume median diameter D 50 of the obtained resin particles is shown in Table 2.

[0089] Production Examples X2, Y1 (Production of resin particle dispersion liquids X-2, Y-1) Resin particle dispersions X-2 and Y-1 were obtained in the same manner as in Production Example X1, except that the resin A-1 used was changed to resin A-2 or B-1. The volume median diameter D of the obtained resin particles 50 is shown in Table 2.

[0090] [Table 2]

[0091] [Production of Release Agent Particle Dispersion] Production Example W1 (Production of Release Agent Particle Dispersion W-1) To a 1 L beaker, 30 g of deionized water, 100 g of resin particle dispersion X-1, and 50 g of paraffin wax "HNP-9" (manufactured by Nippon Seiro Co., Ltd., melting point 75°C) were added, and the mixture was melted while maintaining the temperature at 90 to 95°C, stirred to obtain a molten mixture. While maintaining the temperature of the obtained molten mixture at 90 to 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 40% by mass, and release agent particle dispersion W-1 was obtained. The volume median diameter D of the release agent particles 50 was 0.29 μm.

[0092] Production Example W2 (Production of Release Agent Particle Dispersion W-2) Release agent particle dispersion W-2 was obtained in the same manner as in Production Example W1, except that the release agent species 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 50 was 0.26 μm.

[0093] [Production of Colorant Particle Dispersion] Production Example E1 (Production of Colorant Particle Dispersion E-1) In a 1 L beaker, 67.5 g of copper phthalocyanine pigment "ECB-301" (manufactured by Dainichi Seika Kogyo Co., Ltd.), 90 g of anionic surfactant "Neoperex (registered trademark) G-15" (manufactured by Kao Corporation, 15 mass% aqueous solution of sodium dodecylbenzenesulfonate), and 149 g of deionized water were mixed and dispersed at room temperature for 3 hours using a homogenizer. Then, deionized water was added so that the solid content concentration became 20 mass% to obtain a colorant particle dispersion liquid E-1. The volume median particle diameter D of the colorant particles 50 was 0.125 μm.

[0094] [Manufacture of toner] Example 1 (Manufacture of toner AT-1) [Step 1 (Production of aggregated particles 1 and 2)] Into a 5 L four-necked flask equipped with a dehydrating tube, a stirring device, and a thermocouple, 500 g of resin particle dispersion liquid X-1, 33 g of mold release agent particle dispersion liquid W-1, 33 g of mold release agent particle dispersion liquid W-2, and 67 g of colorant particle dispersion liquid E-1 were placed and mixed at a temperature of 25°C. Next, while stirring the mixture, an aqueous solution prepared by dissolving 46 g of ammonium sulfate in 1345 g of deionized water and adding a 4.8 mass% aqueous potassium hydroxide solution to adjust the pH to 8.0 was added dropwise at 25°C over 30 minutes, and then the temperature was raised to 55°C over 1 hour. The mixture was held at 55°C until the volume median particle diameter D of the aggregated particles 50 became 6.6 μm to obtain an aggregated particle 1 dispersion liquid. The aggregated particle 1 dispersion liquid was adjusted to 51°C, and while maintaining the temperature at 51°C, 75 g of resin particle dispersion liquid X-1 was added over 90 minutes to obtain an aggregated particle 2 dispersion liquid in which the aggregated particles 1 were coated with resin particles. [Step 2 (Production of fused particles)] To the aggregated particle 2 dispersion liquid obtained in Step 1, 250 g of a 20 mass% aqueous solution of Demol N (sodium salt of β-naphthalenesulfonic acid formalin condensate, manufactured by Kao Corporation), 650 g of deionized water, and 477 g of a 4.8 mass% aqueous potassium hydroxide solution were added. Then, the temperature was raised to 70°C over 1 hour and held at 70°C until the circularity became 0.97 to obtain a dispersion liquid of fused particles in which the aggregated particles 2 were fused. After that, the obtained fused particle dispersion liquid was cooled to 30°C. [Washing step] To the fused particle dispersion obtained in Step 2, an aqueous 1M sulfuric acid solution at 25°C was added to adjust the pH of the fused particle dispersion to 4. After separation of the solid content by suction filtration and washing with deionized water at 25°C, suction filtration was performed at 25°C for 2 hours. Thereafter, vacuum drying was carried out at 33°C for 24 hours using a vacuum isothermal dryer "DRV622DA" (manufactured by ADVANTEC) to obtain toner particles T-1. [Step 3 (External addition treatment of toner particles)] 100 parts by mass of toner particles T-1 and 1.8 parts by mass of hydrophobic silica "R972 (manufactured by Nippon Aerosil Co., Ltd., number average particle diameter; 16 nm)" were placed in a Henschel mixer and stirred, and then passed through a 150-mesh sieve to obtain toner AT-1. The obtained toner AT-1 was evaluated as follows. The physical property values of toner particles T-1 and the evaluation results of toner AT-1 are shown in Table 3.

[0095] [Evaluation method] [Durability of toner (time until streak formation)] A toner was mounted on the ID cartridge of a commercially available printer "Microline (registered trademark) 5400" (manufactured by Oki Electric Industry Co., Ltd.) equipped with an ID cartridge modified so that the developing roller could be visually observed. Under the conditions of a temperature of 10°C and a relative humidity of 20%, an idle running operation was performed at 70 r / min (equivalent to 36 sheets / min), and the occurrence of streaks on the surface of the developing roller was visually observed every 1 hour, and the time until streaks were first observed was measured. "The time until streaks were first observed - 1 hour" was defined as the streak generation time and used as an index of durability. The larger the numerical value, the better the durability. Note that streaks refer to a state in which there is a variation in the amount of toner adhering to the developing roller, and due to the occurrence of streaks, shading occurs in the image density during printing.

[0096] Examples 2 to 9 (Manufacture of toners AT-2 to AT-9) Volume median diameter D of agglomerated particles 1 50Except for changing the type of the resin particle dispersion coating the aggregated particles 1, the pH of the fused particle dispersion during washing, the type of the external additive, and / or the amount of the external additive as shown in Table 3, toner particles T-2 to T-8 and toner AT-2 to AT-9 were obtained in the same manner as in Example 1. Table 3 shows the physical property values of the obtained toner particles T-2 to T-8 and the evaluation results of toner AT-2 to AT-9.

[0097] Comparative Example 1 (Production of Toner AT’-1) Fused particles were prepared in the same procedure as in Example 1 except that no acidic substance was added. The fused particle dispersion was suction filtered, the solid content was separated, washed with deionized water at 25 °C, and then suction filtered at 25 °C for 2 hours. Thereafter, vacuum drying was performed at 33 °C for 24 hours using a vacuum isothermal dryer “DRV622DA” (manufactured by ADVANTEC) to obtain toner particles T’-1. The external addition treatment of the toner particles T’-1 was performed in the same procedure as in Example 1 to obtain toner AT’-1. Table 3 shows the physical property values of the obtained toner particles T’-1 and the evaluation results of toner AT’-1.

[0098] Comparative Example 2 (Production of Toner AT’-2) Except for changing the resin particle dispersion used for the production of the aggregated particles 1, the volume median diameter D of the aggregated particles 1 50 and the resin particle dispersion coating the aggregated particles 1 and the amount of the external additive as shown in Table 3, toner particles T’-2 and toner AT’-2 were obtained in the same manner as in Example 1. Table 3 shows the physical property values of the obtained toner particles T’-2 and the evaluation results of toner AT’-2.

[0099] Comparative Examples 3 and 4 (Production of Toner AT’-3 and AT’-4) Except for changing the volume median diameter D of the aggregated particles 50 and the amount of the external additive as shown in Table 3, toner particles T’-3, T’-4 and toner AT’-3, AT’-4 were obtained in the same manner as in Comparative Example 1. Table 3 shows the physical property values of the obtained toner particles T’-3, T’-4 and the evaluation results of toner AT’-3, AT’-4.

[0100] Comparative Example 5 Aggregated particles 2 were produced in the same procedure as in Example 1. To the obtained dispersion of the aggregated particles 2, 250 g of a 20 wt% aqueous solution of Demol N (sodium salt of β-naphthalene sulfonic acid formalin condensate, manufactured by Kao Corporation), 650 g of deionized water, and 477 g of a 4.8 mass% potassium hydroxide aqueous solution were added. The temperature was raised to 70°C over 1 hour and maintained at 70°C until the circularity reached 0.95, to obtain a dispersion of fused particles in which the aggregated particles 2 were fused. Then, the obtained dispersion of the fused particles was cooled to 30°C. The dispersion of the fused particles was suction filtered, the solid content was separated, washed with deionized water at 25°C, and then suction filtered at 25°C for 2 hours. Thereafter, vacuum drying was performed at 33°C for 24 hours using a vacuum constant temperature dryer "DRV622DA" (manufactured by ADVANTEC) to obtain toner particles T'-5. The external addition treatment of the toner particles T'-5 was performed in the same procedure as in Example 1 to obtain toner AT'-5. The physical property values of the obtained toner particles T'-5 and the evaluation results of toner AT'-5 are shown in Table 3.

[0101] [Table 3]

[0102] From Table 3, it can be seen that the electrostatic charge image developing toner of the present invention containing the polyester resin A, having a volume median particle diameter D 50 [μm] of 4 ≦ x ≦ 10 and the BET specific surface area of the toner particles satisfying the formula (1) is excellent in durability (Examples 1 to 9). On the other hand, it can be seen that toners in which the BET specific surface area of the toner particles does not satisfy the formula (1) (Comparative Examples 1, 3 to 5) and toners not containing the polyester resin A (Comparative Example 2) are insufficient or inferior in durability.

Claims

1. A toner for developing an electrostatic charge image, wherein an external additive is adhered to toner particles, the toner particles contain a polyester resin A which is a polycondensate of an alcohol component (a) containing 80 mol% or more of an aliphatic diol (a1) and a carboxylic acid component (b), The BET specific surface area of toner particles [m ２ / g] satisfies the following formula (1), and the toner is for electrostatic charge image development. 0.026x ２ -0.46x + 2.70 ≤ BET specific surface area ≤ 0.026x ２ -0.46x + 4.00... Formula (1) (However, x is the volume median particle diameter D of the toner particles ５０ [μm], and 4 ≤ x ≤ 10.)

2. The toner for developing an electrostatic charge image according to claim 1, wherein the aliphatic diol (a1) contains an aliphatic diol having 2 to 5 carbon atoms, and the amount of the aliphatic diol having 2 to 5 carbon atoms in the alcohol component (a) is 60 mol% or more.

3. The toner for developing an electrostatic charge image according to claim 1 or 2, wherein the toner particles have a core-shell structure.

4. The toner for developing an electrostatic charge image according to claim 3, wherein the shell portion contains the polyester resin A.

5. The toner for developing an electrostatic charge image according to claim 1 or 2, wherein the number average particle diameter of the primary particles of the external additive is 6 nm or more and 50 nm or less.

6. The toner for developing an electrostatic charge image according to claim 1 or 2, wherein the roundness of the toner particles is 0.95 or more and 1.00 or less.

7. A method for manufacturing a toner for developing an electrostatic charge image, comprising the following steps 1 to 3, Step 1: A step of aggregating resin particles in an aqueous medium Step 2: A step of fusing the aggregated particles obtained in Step 1 Step 3: A step of mixing the toner particles obtained in Step 2 and an external additive The resin particles contain a polyester resin A which is a polycondensate of an alcohol component (a) containing 80 mol% or more of an aliphatic diol (a1) and a carboxylic acid component (b), The BET specific surface area of the toner particles [m ２ / g] satisfies the following formula (1), a method for producing an electrostatic charge image developing toner. 0.026x ２ -0.46x + 2.70 ≤ BET specific surface area ≤ 0.026x ２ -0.46x + 4.00... Equation (1) (However, x is the volume median particle diameter D ５０ [μm], and 4 ≤ x ≤ 10.)

8. The method for manufacturing a toner for developing an electrostatic charge image according to claim 7, which has the following washing step after Step 2 and before Step 3. Washing process: A step of adding an acidic substance to the fused particle dispersion obtained in Step 2, adjusting the pH of the fused particle dispersion to 3 or more and less than 11, and then washing with water

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