Manufacturing method of electrostatic image developing toner

Abstract

To provide a manufacturing method of electrostatic image developing toner with narrow particle size distribution of toner particles and a high chargeability even after storage in high temperature and high humidity environments, and capable of preventing fogging when printing images in high temperature and high humidity environments.SOLUTION: The manufacturing method of electrostatic image developing toner includes step 1 and step 2 below. Step 1: a series of processing of obtaining agglomerated particles by aggregating resin particles containing crystalline polyester resin in an aqueous medium in the presence of a block copolymer of polyethylene glycol and polypropylene glycol. Step 2: a series of processing of obtaining fused particles by fusing the aggregated particles obtained in step 1.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for producing a toner for developing electrostatic images used in developing latent images formed in electrophotography, electrostatic recording, electrostatic printing and the like. [Background technology]

[0002] In the field of electrophotography, with the development of electrophotographic systems, there is a demand for the development of electrophotographic toners that can meet the demands of higher image quality and higher speeds. In order to meet the demands of higher image quality, a method for obtaining a toner that has a narrow particle size distribution, a small particle size, and a fixing property that can meet the demands of higher speeds is being carried out, in which fine resin particles or the like are aggregated and fused in an aqueous medium to obtain a toner, namely, a chemical toner, which is produced by an aggregation and fusion method (emulsion aggregation method, aggregation and coalescence method).

[0003] For example, Patent Document 1 describes a toner for developing electrostatic images, which contains toner particles having a core portion containing a styrene (meth)acrylic modified polyester resin and a colorant, and a shell layer that covers the core portion and contains a styrene (meth)acrylic modified polyester resin and a release agent, for the purpose of providing a toner for developing electrostatic images with improved color development. Patent Document 2 describes a negatively charged toner having excellent charging stability when printing multiple sheets and excellent durability without unevenness in printed images, which is obtained by adding an aqueous medium to a hydrophobic solvent solution in which a colorant, a wax component, and an anionic self-water-dispersible polyester resin are dispersed and dissolved, and then carrying out phase inversion emulsification to obtain toner base particles, to which hydrophobic α-alumina fine particles having a number-average primary particle diameter of 100 to 600 nm and / or hydrophobic silica fine particles having a number-average primary particle diameter of 100 to 600 nm are externally added together with hydrophobic silica fine particles having a number-average primary particle diameter of 7 to 60 nm and hydrophobic titanium oxide fine particles having a number-average primary particle diameter of 10 to 40 nm, and wherein the hydrophobic treatment of the external additive particles is a hydrophobic treatment using a silane coupling agent. Furthermore, Patent Document 3 describes a method for producing a toner by aggregating and fusing base microparticles mainly composed of a binder resin having anionic groups, with the aim of providing a toner and a method for producing the same that are excellent in particle size distribution and storage stability, the method comprising the steps of: (a) preparing a suspension of the base microparticles; (b) aggregating the base microparticles in the suspension of the base microparticles to produce aggregates in the presence of a nonionic surfactant whose aqueous solution has a surface tension of 45 mN / m or more at any concentration equal to or higher than the critical micelle concentration; (c) fusing the aggregates to produce base particles; and (d) producing a toner using the base particles. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-184073 A [Patent Document 2] JP 2011-59693 A [Patent Document 3] JP 2010-237551 A Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, the export of domestically manufactured toner cartridges and printers has increased, and the toner is required to have the performance to withstand such an environment when transported by ship, which may be a high-temperature, high-humidity environment far exceeding the normal usage environment. As a result of the study by the present inventors, it was found that when a crystalline polyester resin and a surfactant such as polyoxyethylene alkyl ether are used in the production of a chemical toner, as in the toner for developing electrostatic images described in Patent Document 1, the crystalline polyester resin and the surfactant are exposed to the surface of the toner particles in a high-temperature, high-humidity environment such as the shipping environment by ship, and the charge amount is significantly reduced, resulting in printing problems such as fog. On the other hand, it was found that when a chemical toner is produced without using any surfactant at all during aggregation in order to completely suppress the reduction in the charge amount and the exposure of the surfactant to the surface of the toner particles in a high-temperature, high-humidity environment, the aggregated particles are not stable in water, and the print image quality is significantly reduced due to problems such as the generation of coarse particles and broadening of the particle size distribution. The present invention relates to a method for producing a toner for developing electrostatic images, which has a narrow particle size distribution, exhibits high chargeability even after storage in a high-temperature, high-humidity environment, and suppresses the occurrence of fog when printing images in a high-temperature, high-humidity environment. [Means for solving the problem]

[0006] The present inventors have discovered a method for producing a toner for developing electrostatic images, which, by agglomerating resin particles containing a crystalline polyester resin in the presence of a surfactant having a specific structure during the production of a chemical toner, can suppress the generation of coarse particles and broadening of the particle size distribution in the toner particles even when a crystalline polyester resin is used, and which can produce a toner for developing electrostatic images that exhibits high charging properties even after storage under high temperature and high humidity conditions and in which the generation of fog during printing is suppressed. The present invention relates to the following [1]. [1] A method for producing a toner for developing electrostatic images, comprising the following steps 1 and 2: Step 1: A step of aggregating resin particles containing a crystalline polyester resin in an aqueous medium in the presence of a block copolymer of polyethylene glycol and polypropylene glycol to obtain aggregated particles. Step 2: A step of fusing the aggregated particles obtained in step 1 to obtain fused particles. Effect of the Invention

[0007] According to the present invention, there is provided a method for producing a toner for developing electrostatic images, which has a narrow particle size distribution of toner particles, exhibits high electrostatic chargeability even after storage in a high-temperature, high-humidity environment, and suppresses the occurrence of fog when printing images in a high-temperature, high-humidity environment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] [Method of manufacturing toner for developing electrostatic images] The method for producing a toner for developing electrostatic images of the present invention includes step 1 of aggregating resin particles containing a crystalline polyester resin in an aqueous medium in the presence of a block copolymer of polyethylene glycol and polypropylene glycol to obtain aggregated particles, and step 2 of fusing the aggregated particles obtained in step 1 to obtain fused particles. According to the above-mentioned manufacturing method, a toner for developing electrostatic images can be obtained which has a narrow particle size distribution of toner particles, exhibits high electrostatic chargeability even after storage in a high-temperature, high-humidity environment, and suppresses the occurrence of fog when printing images in a high-temperature, high-humidity environment.

[0009] The reason why the manufacturing method of the present invention can provide a toner for developing electrostatic images (hereinafter, also simply referred to as "toner") that has a narrow particle size distribution, exhibits high charging properties even after storage in a high-temperature, high-humidity environment, and suppresses the occurrence of fog when printing images in a high-temperature, high-humidity environment is not clear, but is thought to be as follows. Surfactants have the function of dispersing and stabilizing polyester resin particles and aggregated particles in an aqueous medium, and are compounds that play an important role in the production of chemical toners by the aggregation and fusion method. However, surfactants are generally water-soluble and therefore have high electrical conductivity, and it is believed that if the surfactant remains inside the toner after production, the surfactant migrates to the toner surface in a high-temperature, high-humidity environment, and the charge leaks from the surfactant when charging. In addition, when a toner is produced using a crystalline polyester resin, the crystalline polyester resin also migrates to the toner surface in a high-temperature, high-humidity environment, which is also believed to be a factor in the decrease in the charge amount. As a result of the inventors' investigations, it was found that the surfactant used to stabilize the system during the aggregation process of aggregating resin particles in the chemical toner production process has a significant effect on the chargeability of the resulting toner.

[0010] After intensively studying measures to improve the situation, the present inventors have found that by using a block copolymer of polyethylene glycol and polypropylene glycol as a surfactant in the production of chemical toner, the resulting chemical toner maintains high chargeability even after storage in a high-temperature, high-humidity environment, and good printed images can be obtained. This is believed to be because the hydrophobic polypropylene glycol chains in the block copolymer are adsorbed to domains derived from the highly hydrophobic crystalline polyester resin, and the hydrophilic polyethylene glycol chains gather in the toner, improving the dispersibility of the crystalline polyester. Furthermore, since the block copolymer is a polymer, even when stored in a high-temperature, high-humidity environment, the migration of the crystalline polyester resin and the surfactant to the toner surface is suppressed, thereby suppressing the decrease in the charge amount of the toner, and it is believed that the occurrence of fog is suppressed when printing images in a high-temperature, high-humidity environment.

[0011] The definitions of various terms used in this specification are given below. Whether a 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 endothermic peak temperature (softening point (°C) / maximum endothermic peak temperature (°C)) in the measurement method described in the examples below. A crystalline resin is one with 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, has a crystallinity index of less than 0.6 or more than 1.4. The crystallinity index can be appropriately adjusted by the types and ratios of raw material monomers, as well as production conditions such as reaction temperature, reaction time, and cooling rate. The carboxylic acid component of the polyester resin includes not only the compound itself, but also anhydrides that decompose during the reaction to generate an acid, and alkyl esters of each carboxylic acid (alkyl groups having 1 to 3 carbon atoms). With respect to hydrocarbon groups, the references "(iso or tertiary)" and "(iso)" in parentheses refer to both the cases with and without the prefixes present; the absence of the prefixes indicates normal. "(Meth)acrylic acid" means at least one selected from acrylic acid and methacrylic acid. By "styrenic compound" is meant unsubstituted or substituted styrene.

[0012] [Process 1] In step 1, resin particles containing a crystalline polyester resin are aggregated in an aqueous medium in the presence of a block copolymer of polyethylene glycol and polypropylene glycol to obtain aggregated particles.

[0013] [Crystalline polyester resin] The crystalline polyester resin (hereinafter also referred to as "crystalline polyester resin C" or "resin C") is a polycondensation product of an alcohol component and a carboxylic acid component. The alcohol component is preferably an α,ω-aliphatic diol. The α,ω-aliphatic diol preferably has 2 or more carbon atoms, and preferably has 16 or less, more preferably 14 or less, and further preferably 12 or less carbon atoms. 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, and 1,14-tetradecanediol. Among these, ethylene glycol, 1,6-hexanediol, 1,10-decanediol, and 1,12-dodecanediol are preferred, ethylene glycol and 1,10-decanediol are more preferred, and ethylene glycol is even more preferred.

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

[0015] The alcohol component may contain other alcohol components different from the α,ω-aliphatic diol. Examples of the other alcohol components include aliphatic diols other than α,ω-aliphatic diols, such as 1,2-propanediol and neopentyl glycol; 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. These alcohol components may be used alone or in combination.

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

[0017] The amount of the aliphatic dicarboxylic acid in the carboxylic acid component is preferably 70 mol % or more, more preferably 80 mol % or more, even more preferably 85 mol % or more, and is 100 mol % or less, preferably 95 mol % or less. From the viewpoints of low-temperature fixing property and chargeability of the toner and reduction of fog in the obtained image, it is preferable that the carboxylic acid component further contains a monocarboxylic acid. From the same viewpoints, the number of carbon atoms of the monocarboxylic acid is preferably 6 or more, more preferably 8 or more, more preferably 12 or more, and more preferably 16 or more, and is preferably 24 or less, more preferably 22 or less, and more preferably 20 or less. The monocarboxylic acid is preferably an aliphatic monocarboxylic acid, such as caprylic acid, pelargonic acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, etc. Among these, preferred are caprylic acid, lauric acid, stearic acid, and behenic acid, and from the viewpoint of low-temperature fixing property and electrostatic property of the toner and from the viewpoint of reducing fog in the obtained image, more preferred are stearic acid and behenic acid, and even more preferred is stearic acid. The amount of monocarboxylic acid in the carboxylic acid component is preferably 1 mol% or more, more preferably 5 mol% or more, even more preferably 7 mol% or more, and preferably 35 mol% or less, more preferably 30 mol% or less, even more preferably 20 mol% or less, even more preferably 15 mol% or less.

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

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

[0020] The resin C may be produced, for example, by polycondensing raw material monomers containing an alcohol component and a carboxylic acid component.

[0021] The polycondensation of the alcohol component and the carboxylic acid component can be carried out, for example, in an inert gas atmosphere, in the presence of an esterification catalyst, an esterification promoter, a polymerization inhibitor, etc., as necessary, at a temperature of about 120°C or higher and 250°C or lower. Examples of the esterification catalyst include tin compounds such as dibutyltin oxide and tin(II) di(2-ethylhexanoate), and titanium compounds such as titanium diisopropoxybis(triethanolaminate). Examples of the esterification promoter that can be used together with the esterification catalyst include gallic acid (3,4,5-trihydroxybenzoic acid). The amount of the esterification catalyst used is preferably 0.01 parts by mass or more and 10 parts by mass or less relative to 100 parts by mass in total of the alcohol component and the carboxylic acid component which are raw material monomers for the resin C. The amount of the esterification promoter used is preferably 0.001 part by mass or more and 1 part by mass or less based on 100 parts by mass in total of the alcohol component and the carboxylic acid component. Furthermore, examples of the polymerization inhibitor include radical polymerization inhibitors such as 4-tert-butylcatechol. When a polymerization inhibitor is used, the amount of the polymerization inhibitor used is preferably 0.01 part by mass or more and 1 part by mass or less based on 100 parts by mass in total of the alcohol component and the carboxylic acid component.

[0022] (Physical properties of crystalline polyester resin C) The softening point of Resin C is preferably 60°C or higher, more preferably 70°C or higher, and even more preferably 80°C or higher, and from the viewpoint of further improving low-temperature fixability, it is preferably 150°C or lower, more preferably 120°C or lower, and even more preferably 100°C or lower. The melting point of resin C is preferably 50°C or higher, more preferably 60°C or higher, even more preferably 70°C or higher, and even more preferably 80°C or higher, and from the viewpoint of further improving low-temperature fixability, it is preferably 100°C or lower, more preferably 90°C or lower, and even more preferably 85°C or lower.

[0023] The acid value of resin C is preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g or more, and preferably 35 mgKOH / g or less, more preferably 25 mgKOH / g or less, and even more preferably 20 mgKOH / g or less. The softening point, melting point, and acid value of the resin C can be appropriately adjusted by the type and amount of the raw material monomer, as well as production conditions such as reaction temperature, reaction time, and cooling rate, and are determined by the method described in the Examples below. When two or more types of resin C are used in combination, it is preferable that the softening point, melting point, and acid value obtained as a mixture of them are each within the above-mentioned ranges.

[0024] The content of resin C in the toner particles is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, from the viewpoint of the low-temperature fixing property and electrostatic property of the toner, and from the viewpoint of reducing fog in the obtained image, and is preferably 36% by mass or less, more preferably 30% by mass or less, even more preferably 25% by mass or less.

[0025] In the resin particles, the mass ratio of resin C to the amorphous polyester resin (resin A) described later [resin C / resin A] is, from the viewpoint of the thermal responsiveness of the toner, preferably 0.10 or more, more preferably 0.20 or more, even more preferably 0.30 or more, and is preferably 0.60 or less, more preferably 0.55 or less, even more preferably 0.50 or less.

[0026] [Block copolymer of polyethylene glycol and polypropylene glycol] The block copolymer of polyethylene glycol and polypropylene glycol (hereinafter also referred to as "block copolymer") may be a block copolymer having at least one polyethylene glycol segment and at least one polypropylene glycol segment, but is preferably a polyethylene glycol-polypropylene glycol-polyethylene glycol type triblock copolymer, more preferably a triblock copolymer represented by the following formula (1), and even more preferably a triblock copolymer represented by the following formula (2).

[0027] [ka]

[0028] In formula (1), R 1 and R 2 each independently represents a hydrogen atom or a hydrocarbon group having from 1 to 24 carbon atoms. The hydrocarbon group may be linear or branched. R 1 and R 2 is preferably a hydrogen atom or a linear or branched alkyl group having from 1 to 5 carbon atoms, more preferably a hydrogen atom. R 1 and R 2 Examples of the alkyl group having 1 to 5 carbon atoms that can be used in a preferred embodiment include a methyl group, an ethyl group, various propyl groups, various butyl groups, and various pentyl groups. In formula (1), x and z represent the average number of moles of ethylene oxide added, and y represents the average number of moles of propylene oxide added. x, y, and z are each independently 1 or more and 500 or less, preferably 20 or more and 300 or less. In addition, the ratio of the sum of x and z to y [(x+z) / y] is preferably 0.1 or more and 7.0 or less.

[0029] [ka]

[0030] In formula (2), m represents the average number of moles of propylene oxide added, and n represents the average number of moles of ethylene oxide added. m is 10 or more, preferably 20 or more, and 80 or less, preferably 70 or less. n is 1 or more, preferably 20 or more, more preferably 40 or more, even more preferably 65 or more, and is 200 or less, preferably 170 or less. Moreover, the ratio of 2n to m (2n / m) is preferably 0.1 or more and 7.0 or less.

[0031] From the viewpoint of suppressing a decrease in the charge amount in a high-temperature and high-humidity environment, the content of polyethylene glycol segments in the block copolymer of polyethylene glycol and polypropylene glycol is preferably 5% by mass or more, more preferably 30% by mass or more, even more preferably 45% by mass or more, even more preferably 60% by mass or more, even more preferably 75% by mass or more, and is preferably 90% by mass or less, more preferably 85% by mass or less.

[0032] As the block copolymer, commercially available products can also be used, and preferred examples thereof include "ADEKA (registered trademark) Pluronic F108", "ADEKA (registered trademark) Pluronic F88", "ADEKA (registered trademark) Pluronic F68", "ADEKA (registered trademark) Pluronic F87", "ADEKA (registered trademark) Pluronic P85", "ADEKA (registered trademark) Pluronic P84" and "ADEKA (registered trademark) Pluronic L81" (all manufactured by ADEKA Corporation).

[0033] The amount of the block copolymer of polyethylene glycol and polypropylene glycol added (used) in step 1 is preferably 0.5 parts by mass or more, more preferably 2.0 parts by mass or more, and even more preferably 3.5 parts by mass or more, relative to 100 parts by mass of the crystalline polyester resin, and is preferably 10 parts by mass or less, and more preferably 8 parts by mass or less.

[0034] [Amorphous polyester resin] In step 1, it is preferable to obtain aggregated particles by aggregating resin particles containing a crystalline polyester resin and an amorphous polyester resin in an aqueous medium in the presence of a block copolymer of polyethylene glycol and polypropylene glycol. The crystalline polyester resin and the amorphous polyester resin may be contained in the same resin particles, or may be contained in different resin particles.

[0035] The amorphous polyester resin (hereinafter also referred to as "polyester resin A" or "resin A") is, for example, an amorphous polyester resin containing a polycondensate of an alcohol component and a carboxylic acid component. Examples of the resin A include polyester resin and modified polyester resin. Examples of the modified polyester resin include urethane modified polyester resin, epoxy modified polyester resin, and composite resin containing polyester resin segment and addition polymerization resin segment. Among these, the resin A is preferably polyester resin and composite resin.

[0036] Examples of the alcohol component of the resin A include alkylene oxide adducts of aromatic diols, linear or branched aliphatic diols, alicyclic diols, and trihydric or higher polyhydric alcohols. Among these, alkylene oxide adducts of aromatic diols are preferred from the viewpoint of obtaining a toner having excellent low-temperature fixing properties. The alkylene oxide adduct of an aromatic diol is preferably an alkylene oxide adduct of bisphenol A, more preferably an alkylene oxide adduct of formula (I):

[0037] [ka] (In the formula, OR 1 and R 2 O is an oxyalkylene group, and R 1 and R 2each independently represents an ethylene group or a propylene group, x and y represent the average number of moles of alkylene oxide added and are each a positive number, and the sum of x and y is 1 or more, preferably 1.5 or more, and more preferably 1.8 or more, and is 16 or less, preferably 8 or less, more preferably 4 or less, and even more preferably 3 or less, and even more preferably 2.5 or less.

[0038] Examples of the alkylene oxide adduct of bisphenol A represented by formula (I) include a propylene oxide adduct of bisphenol A and an ethylene oxide adduct of bisphenol A. Among these, it is preferable to contain at least a propylene oxide adduct of bisphenol A. The content of the alkylene oxide adduct of bisphenol A in the alcohol component is preferably 80 mol % or more, more preferably 90 mol % or more, and 100 mol % or less, and further preferably 100 mol %.

[0039] Examples of linear or branched aliphatic diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2,2-dimethyl-1,3-propanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, and 1,12-dodecanediol. Examples of alicyclic diols include hydrogenated bisphenol A [2,2-bis(4-hydroxycyclohexyl)propane] and adducts of hydrogenated bisphenol A with alkylene oxides having 2 to 4 carbon atoms (average number of moles added: 2 to 12). Examples of trihydric or higher polyhydric alcohols include glycerin, pentaerythritol, trimethylolpropane, and sorbitol. These alcohol components may be used alone or in combination of two or more.

[0040] Examples of the carboxylic acid component of the resin A include dicarboxylic acids and trivalent or higher polyvalent carboxylic acids. Examples of dicarboxylic acids 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 preferred. Examples of aromatic dicarboxylic acids include phthalic acid, isophthalic acid, and terephthalic acid. Among these, isophthalic acid and terephthalic acid are preferred, and terephthalic acid is more preferred. The amount of aromatic dicarboxylic acid in the carboxylic acid component is preferably 20 mol% or more, more preferably 30 mol% or more, even more preferably 40 mol% or more, and is preferably 85 mol% or less, more preferably 80 mol% or less, even more preferably 75 mol% or less.

[0041] The linear or branched aliphatic dicarboxylic acid preferably has 2 or more, more preferably 3 or more, and preferably has 30 or less, more preferably 20 or less. Examples of linear or branched aliphatic dicarboxylic acids include oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid, sebacic acid, dodecanedioic acid, azelaic acid, and succinic acid substituted with an aliphatic hydrocarbon group having 1 to 20 carbon atoms. Examples of succinic acid substituted with an aliphatic hydrocarbon group having 1 to 20 carbon atoms include dodecylsuccinic acid, dodecenylsuccinic acid or its anhydride, and octenylsuccinic acid. Among these, fumaric acid, sebacic acid, adipic acid, and succinic acid substituted with an aliphatic hydrocarbon group having 1 to 20 carbon atoms are preferred. The amount of linear or branched aliphatic dicarboxylic acid in the carboxylic acid component is preferably 1 mol % or more, more preferably 3 mol % or more, even more preferably 5 mol % or more, and preferably 60 mol % or less, more preferably 55 mol % or less, even more preferably 50 mol % or less.

[0042] The trivalent or higher polyvalent carboxylic acid is preferably a trivalent carboxylic acid, and examples thereof include trimellitic acid and its anhydride. When a trivalent or higher polycarboxylic acid is contained, the amount of the trivalent or higher polycarboxylic acid in the carboxylic acid component is preferably 1 mol % or more, more preferably 1.5 mol % or more, even more preferably 2 mol % or more, and preferably 30 mol % or less, more preferably 20 mol % or less, even more preferably 15 mol % or less. These carboxylic acid components may be used alone or in combination of two or more.

[0043] The equivalent ratio of the carboxyl groups of the carboxylic acid component to the hydroxyl groups of the alcohol component [COOH groups / OH groups] is preferably 0.7 or more, more preferably 0.75 or more, and is preferably 1.3 or less, more preferably 1.2 or less.

[0044] When the resin A is a composite resin, an example of the addition polymerized resin segment is an addition polymer of raw material monomers containing a styrene-based compound. Examples of the styrene-based compound include unsubstituted or substituted styrene. Examples of the substituent substituted on styrene include an alkyl group having 1 to 5 carbon atoms, a halogen atom, an alkoxy group having 1 to 5 carbon atoms, a sulfonic acid group, or a salt thereof. Examples of styrene-based compounds include styrene, methylstyrene, α-methylstyrene, β-methylstyrene, tert-butylstyrene, chlorostyrene, chloromethylstyrene, methoxystyrene, styrenesulfonic acid, and salts thereof. Among these, styrene is preferred. The content of the styrene-based compound in the raw material monomers of the addition polymerization resin segment is preferably 50% by mass or more, more preferably 65% ​​by mass or more, even 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, even more preferably 85% by mass or less.

[0045] Examples of raw material monomers other than styrene-based compounds include (meth)acrylic acid esters such as alkyl (meth)acrylate, benzyl (meth)acrylate, and dimethylaminoethyl (meth)acrylate; olefins such as ethylene, propylene, and butadiene; halovinyls such as vinyl chloride; vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as methyl vinyl ether; vinylidene halides such as vinylidene chloride; and 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 in the alkyl group in the alkyl (meth)acrylate is preferably 1 or more, more preferably 4 or more, even more preferably 6 or more, and is preferably 24 or less, more preferably 22 or less, even more preferably 20 or less. Examples of the alkyl (meth)acrylate 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, and (iso)behenyl (meth)acrylate. Of these, 2-ethylhexyl (meth)acrylate or stearyl (meth)acrylate is preferred, stearyl (meth)acrylate is more preferred, and stearyl methacrylate is even more preferred.

[0046] In the raw material monomers of the addition polymerization resin segment, the content of the (meth)acrylic acid ester is preferably 5 mass% or more, more preferably 10 mass% or more, even more preferably 15 mass% or more, and preferably 50 mass% or less, more preferably 35 mass% or less, even more preferably 25 mass% or less.

[0047] The total amount of the styrene-based compound and the (meth)acrylic acid ester in the raw material monomers of the addition polymerization resin segment is preferably 80 mass % or more, more preferably 90 mass % or more, even more preferably 95 mass % or more, and even more preferably 100 mass %.

[0048] The composite resin preferably has a constitutional unit derived from a bireactive monomer bonded via a covalent bond to a polyester resin segment and an addition polymerization resin segment. The term "structural unit derived from a bireactive monomer" refers to a unit formed by reaction of a functional group and an addition polymerizable group of a bireactive monomer. An example of the addition polymerizable group is a carbon-carbon unsaturated bond (ethylenically unsaturated bond). Examples of the bireactive monomer include addition polymerizable monomers having at least one functional group selected from a hydroxyl group, a carboxyl 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 carboxyl group are preferred, and addition polymerizable monomers having a carboxyl group are more preferred. 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 reactivity in both the polycondensation reaction and the addition polymerization reaction, acrylic acid and methacrylic acid are preferred, and acrylic acid is more preferred. When the bireactive monomer is an addition polymerizable monomer having a carboxy group, the amount of the constitutional unit derived from the bireactive monomer is preferably 1 part by mol or more, more preferably 5 parts by mol or more, even more preferably 8 parts by mol or more, and preferably 30 parts by mol or less, more preferably 25 parts by mol or less, even more preferably 20 parts by mol or less, relative to 100 parts by mol of the alcohol component of the polyester resin segment of the composite resin.

[0049] The content of the polyester resin segment in the composite resin is preferably 40% by mass or more, more preferably 45% by mass or more, and even more preferably 55% by mass or more, and is preferably 95% by mass or less, more preferably 85% by mass or less, and even more preferably 75% by mass or less, based on the total amount of the polyester resin segment and the addition polymerization resin segment. The constitutional unit derived from the bireactive monomer is defined as a polyester resin segment.

[0050] The content of the addition polymerization resin segment in the composite resin is preferably 5 mass% or more, more preferably 15 mass% or more, even more preferably 25 mass% or more, and preferably 60 mass% or less, more preferably 55 mass% or less, even more preferably 45 mass% or less, based on the total amount of the polyester resin segment and the addition polymerization resin segment.

[0051] The amount of the constitutional units derived from the bireactive monomer in the composite resin is preferably 0.1 mass% or more, more preferably 0.5 mass% or more, even more preferably 0.8 mass% or more, and is preferably 10 mass% or less, more preferably 7 mass% or less, even more preferably 4 mass% or less, based on the total amount of the polyester resin segment and the addition polymerization resin segment.

[0052] The total amount of the polyester resin segment and the addition polymerization resin segment in the composite resin is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and is 100% by mass or less, and even more preferably 100% by mass.

[0053] The above amount is calculated based on the ratio of the amounts of the polyester resin segment, the raw material monomer for the addition polymerization resin segment, the bireactive monomer, and the radical polymerization initiator, and the mass of the polyester resin segment, etc. is based on the mass excluding the mass of water generated by polycondensation. When a radical polymerization initiator is used, the mass of the radical polymerization initiator is calculated by including it in the addition polymerization resin segment.

[0054] (Production method of polyester resin A) <Method for producing amorphous polyester resin> When the resin A is a polyester resin, the resin A may be produced, for example, in the same manner as the resin C described above, by polycondensing raw material monomers containing an alcohol component and a carboxylic acid component.

[0055] <Method of manufacturing composite resin> When resin A is a composite resin containing a polyester resin segment and an addition polymerization resin segment, it 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 raw material monomers of the addition polymerization resin segment and a bireactive monomer. Step B may be carried out after step A, step B may be carried out after step A, or step A and step B may be carried out simultaneously. A method is preferred in which a part of the carboxylic acid component is subjected to a polycondensation reaction in step A, and then step B is carried out, and thereafter the remainder of the carboxylic acid component is added to the polymerization system to further proceed with the polycondensation reaction in step A and the polycondensation reaction with the carboxy group of the bireactive monomer or the constituent moiety derived from the bireactive monomer.

[0056] In the step A, if necessary, the esterification catalyst and the esterification promoter described in the above-mentioned method for producing the polyester resin may be used in the same amounts to carry out polycondensation. When a monomer having an unsaturated bond such as fumaric acid is used in the polycondensation, the polymerization inhibitor described in the above-mentioned method for producing the polyester resin may be used in the same amount as above, if necessary. The temperature of the polycondensation reaction is preferably 120° C. or higher, more preferably 160° C. or higher, and even more preferably 180° C. or higher, and is preferably 250° C. or lower, more preferably 240° C. or lower. The polycondensation may be carried out in an inert gas atmosphere.

[0057] 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, and further preferably 210° C. or lower.

[0058] (Physical properties of polyester resin A) The softening point of resin A is preferably 70° C. or higher, more preferably 90° C. or higher, and even more preferably 100° C. or higher, and is preferably 140° C. or lower, more preferably 130° C. or lower, and even more preferably 125° C. or lower. The glass transition temperature of resin A is preferably 30°C or higher, more preferably 35°C or higher, and even more preferably 40°C or higher, and is preferably 80°C or lower, more preferably 75°C or lower, and even more preferably 70°C or lower.

[0059] The acid value of Resin A is preferably 3 mgKOH / g or more, more preferably 5 mgKOH / g or more, even more preferably 8 mgKOH / g or more, and preferably 40 mgKOH / g or less, more preferably 35 mgKOH / g or less, even more preferably 30 mgKOH / g or less.

[0060] The softening point, glass transition temperature, and acid value of Resin A 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, and these values ​​can be determined by the methods described in the examples. When two or more resins A are used in combination, the softening point, glass transition temperature and acid value of the resulting mixture are preferably within the above-mentioned ranges.

[0061] When the toner particles contain resin A, the content of resin A in the toner particles is, from the viewpoints of the low-temperature fixing property and electrostatic property of the toner and of reducing fog in the obtained images, preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 50% by mass or more, and preferably 80% by mass or less, more preferably 70% by mass or less, even more preferably 65% ​​by mass or less.

[0062] [Method for producing aqueous dispersion of resin particles] In step 1, the resin particles can be used in the form of an aqueous dispersion. The aqueous dispersion of resin particles (hereinafter also referred to as "resin particle dispersion") is obtained by mixing and dispersing resin C, resin A, or resins C and A in an aqueous medium as described below. The aqueous medium is preferably one containing water as a main component, and from the viewpoint of improving the dispersion stability of the aqueous dispersion of the resin particles and reducing the environmental load, the content of water in the aqueous medium is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and 100% by mass or less, even more preferably 100% by mass. Deionized water or distilled water is preferable as the water. Examples of components other than water that can be contained in the aqueous medium include organic solvents that dissolve in water, such as alkyl alcohols having 1 to 5 carbon atoms; dialkyl ketones having a total carbon number of 3 to 5, such as acetone and methyl ethyl ketone; and cyclic ethers such as tetrahydrofuran. Among these, methyl ethyl ketone is preferable.

[0063] Mixing and dispersion can be carried out by known methods, but it is preferable to disperse the resin by a phase inversion emulsification method, for example, a method in which an aqueous medium is added to an organic solvent solution of the resin or a molten resin to carry out phase inversion emulsification.

[0064] The organic solvent used for phase inversion emulsification is not particularly limited as long as it dissolves the resin, and examples thereof include methyl ethyl ketone. It is preferable to add a neutralizing agent to the organic solvent solution of the resin. Examples of the neutralizing agent include basic substances. Examples of the basic substance include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, and nitrogen-containing basic substances such as ammonia, trimethylamine, and diethanolamine. The degree of neutralization of the resin contained in the resin particles is preferably 10 mol % or more, more preferably 20 mol % or more, even more preferably 30 mol % or more, even more preferably 40 mol % or more, and is preferably 100 mol % or less, more preferably 80 mol % or less, even more preferably 70 mol % or less. The degree of neutralization of the resin contained in the resin particles can be calculated by the following formula. Degree of neutralization (mol%) = [{weight of neutralizing agent added (g) / equivalent weight of neutralizing agent} / [{weighted average acid value of resin contained in resin particles (mgKOH / g) × weight of resin contained in resin particles (g)} / (56 × 1000)]] × 100

[0065] While stirring the organic solvent solution of the resin or the molten resin, the 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 resin solution in the organic solvent when the aqueous medium is added is preferably equal to or higher than the glass transition temperature of the resin having the highest glass transition temperature among the resins, more preferably equal to or higher than 50°C, even more preferably equal to or higher than 60°C, even more preferably equal to or higher than 70°C, and is preferably equal to or lower than 100°C, more preferably equal to or lower than 90°C, even more preferably equal to or lower than 80°C.

[0066] After the phase inversion emulsification, if necessary, the organic solvent may be removed from the obtained aqueous dispersion by distillation, etc. In this case, the amount of the remaining organic solvent in the aqueous dispersion is preferably 1% by mass or less, more preferably 0.5% by mass or less, and even more preferably substantially 0% by mass.

[0067] Volume median particle diameter D of resin particles in resin particle dispersion 50From the viewpoint of obtaining a toner that can provide high quality images, the particle size is preferably 0.05 μm or more, more preferably 0.08 μm or more, even more preferably 0.1 μm or more, and is preferably 0.5 μm or less, more preferably 0.25 μm or less, even more preferably 0.18 μm or less. From the viewpoint of obtaining a toner that can obtain high-quality images, the CV value (coefficient of variation of particle size distribution) of the resin particles in the resin particle dispersion is preferably 10% or more, more preferably 20% or more, and is preferably 40% or less, more preferably 30% or less. Volume median particle size D 50 The CV value is determined by the method described in the Examples below.

[0068] In step 1, in addition to the resin particles, it is preferable to further aggregate at least one of the colorant and the release agent, and it is more preferable to mix a dispersion liquid containing resin particles (resin particle dispersion liquid) with a colorant particle dispersion liquid containing colorant particles containing a colorant and / or a release agent particle dispersion liquid containing release agent particles containing a release agent to aggregate these particles.

[0069] [Coloring Agent] As the colorant, any of the dyes, pigments, etc. used as toner colorants can be used. Examples of colorants 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 3% by mass or more, more preferably 5% by mass or more, and preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less.

[0070] (Colorant particle dispersion) The colorant particle dispersion is preferably obtained by dispersing the colorant and an aqueous medium using a dispersing machine such as a homomixer, a homogenizer, an ultrasonic dispersing machine, etc. The dispersion is preferably carried out in the presence of a surfactant from the viewpoint of improving the dispersion stability of the colorant. In addition, from the viewpoint of improving the dispersion stability of the colorant, it is also preferable to disperse the colorant particles in the presence of the addition polymer E. The addition polymer E preferably has a constitutional 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, the addition polymer E described in JP-A-2021-026129 is referred to.

[0071] Examples of surfactants for improving the dispersion stability of colorants include nonionic surfactants, anionic surfactants, and cationic surfactants, and from the viewpoint of improving the dispersion stability of colorant particles, nonionic surfactants are preferred. Examples of nonionic surfactants include polyoxyalkylene alkyl ethers, polyoxyalkylene alkenyl ethers, and polyoxyalkylene aryl ethers. Among these, polyoxyethylene aryl ethers are preferred, and polyoxyethylene distyrenated phenyl ether is more preferred.

[0072] From the viewpoint of improving the dispersion stability of the colorant, the content of the surfactant in the colorant particle dispersion liquid is preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and is preferably 50 parts by mass or less, more preferably 45 parts by mass or less, even more preferably 40 parts by mass or less, relative to 100 parts by mass of the colorant.

[0073] 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, even more preferably 30% by mass or less, and even more preferably 25% by mass or less. The solids concentration of the colorant particle dispersion is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and is preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less.

[0074] Volume median particle size D of colorant particles 50 From the viewpoint of improving dispersibility in toner particles, the average particle diameter is preferably 0.05 μm or more, more preferably 0.08 μm or more, even more preferably 0.1 μm or more, and is preferably 0.4 μm or less, more preferably 0.3 μm or less, even more preferably 0.2 μm or less. From the viewpoint of improving dispersibility in the toner particles, the CV value of the colorant particles is preferably 10% or more, more preferably 20% or more, and is preferably 45% or less, more preferably 40% or less, and even more preferably 35% or less. Volume median particle size D of colorant particles 50 and CV values ​​are measured by the methods in the Examples.

[0075] From the viewpoint of improving dispersibility in the toner particles, the amount of the colorant particles is preferably 3 parts by mass or more, more preferably 6 parts by mass or more, and even more preferably 10 parts by mass or more, relative to 100 parts by mass of the resin particles, and is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less.

[0076] [Release Agent] Examples of the release agent include polypropylene wax, polyethylene wax, polypropylene-polyethylene copolymer wax, hydrocarbon waxes such as microcrystalline wax, paraffin wax, Fischer-Tropsch wax, and oxides thereof, ester waxes such as carnauba wax, montan wax, and deacidified waxes thereof, and fatty acid ester wax, fatty acid amides, fatty acids, higher alcohols, and fatty acid metal salts. These may be used alone or in combination of two or more.

[0077] The melting point of the release agent is preferably 60° C. or higher, more preferably 70° C. or higher, and preferably 160° C. or lower, more preferably 140° C. or lower, even more preferably 120° C. or lower, and even more preferably 100° C. or lower. The content of the release agent in the toner particles is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, and preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 12% by mass or less.

[0078] (Release agent particle dispersion) The release agent particle dispersion can be obtained using a surfactant, but from the viewpoint of reducing the amount of surfactant contained in the toner, it is preferable to obtain the release agent by mixing the release agent and the resin particles S. By preparing the release agent particles using the release agent and the resin particles S, the release agent particles are stabilized by the resin particles S, and it becomes possible to disperse the release agent in an aqueous medium without using a surfactant. It is considered that the release agent particle dispersion has a structure in which a large number of resin particles S are attached to the surfaces of the release agent particles.

[0079] The resin constituting the resin particles S in which the release agent is dispersed is preferably a polyester resin, and it is more preferable to use a composite resin D having a polyester resin segment and an addition polymerization resin segment. As the composite resin D, the same composite resin as that shown as the above resin A can be used. In addition, for the release agent particle dispersion and the composite resin D, reference is made to JP 2021-026129 A.

[0080] In step 1, other additives such as a charge control agent, a magnetic powder, a flowability improver, a conductivity adjuster, a reinforcing filler such as a fibrous substance, an antioxidant, an antiaging agent, and a cleaning property improver may be included.

[0081] [Flocculant] In the step of aggregating the resin particles, it is preferable to add an aggregating agent from the viewpoint of efficient aggregation. Examples of the flocculant include cationic surfactants such as quaternary salts, organic flocculants such as polyethyleneimine, and inorganic flocculants. Examples of the inorganic flocculant 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 coagulation properties and obtaining uniformly coagulated particles, inorganic coagulants having a valence of 1 to 5 are preferred, inorganic metal salts having a valence of 1 to 2 and inorganic ammonium salts are more preferred, inorganic ammonium salts are even more preferred, and ammonium sulfate is even more preferred.

[0082] For example, 5 to 50 parts by mass of the aggregating agent is added to a mixed dispersion containing resin particles, release agent particles, and colorant particles at 0° C. to 40° C., relative to 100 parts by mass of the resin in the resin particles, and the resin particles, release agent particles, and colorant particles are aggregated in an aqueous medium to obtain aggregated particles. Furthermore, from the viewpoint of promoting aggregation, it is preferable to increase the temperature of the dispersion after adding the aggregating agent.

[0083] Methods for terminating the aggregation include cooling the dispersion, adding an aggregation terminator, diluting the dispersion, and the like.

[0084] Volume median particle size of agglomerated particles D 50 is preferably 2 μm or more, more preferably 3 μm or more, even more preferably 4 μm or more, and is preferably 10 μm or less, more preferably 8 μm or less, even more preferably 7 μm or less.

[0085] In step 1, after the step of aggregating the resin particles and before the step of fusing, a step of adhering resin particles B containing an amorphous polyester resin (hereinafter also referred to as "polyester resin B" or "resin B") to the obtained aggregated particles (hereinafter also referred to as aggregated particles 1) to obtain aggregated particles 2. By including the step of adhering resin particles B, toner particles having a core-shell structure can be obtained. Here, the resin B is preferably amorphous, and is exemplified by the above-mentioned resin A. The resin particles containing the resin B are obtained as an aqueous dispersion by the same method as the method for producing the aqueous dispersion of the resin particles. Furthermore, in the case where the step 1 includes a step of obtaining aggregated particles 2, it is preferable to terminate the aggregation of the aggregated particles 2 in the step when the aggregated particles 2 have grown to a particle size appropriate for toner particles, and a method of terminating the aggregation by adding an aggregation terminator described below is preferable. The mass ratio of resin particles B to the mass of aggregated particles 1 [resin particles B / aggregated particles 1] is, from the viewpoint of low-temperature fixing property of the toner, preferably 0.01 or more, more preferably 0.02 or more, even more preferably 0.03 or more, and is preferably 0.30 or less, more preferably 0.20 or less, even more preferably 0.10 or less.

[0086] [Aggregation Stopper] From the viewpoint of reliably preventing unnecessary aggregation, an aggregation terminator may be added to the aggregated particles 1 or 2 obtained in step 1 before the aggregated particles 1 or 2 are fused in step 2. The aggregation terminator is preferably a surfactant, more preferably an anionic surfactant. Examples of the anionic surfactant include alkylbenzenesulfonate, alkyl sulfate, alkyl ether sulfate, polyoxyalkylene alkyl ether sulfate, arylsulfonate, and arylsulfonic acid formalin condensate, and are preferably an alkali metal salt of arylsulfonic acid formalin condensate, and more preferably a sodium salt of naphthalenesulfonic acid formalin condensate. These may be used alone or in combination. The aggregation terminator may be added in the form of an aqueous solution. The amount of the aggregation terminator added is preferably 1 part by mass or more, and more preferably 5 parts by mass or more, relative to 100 parts by mass of aggregated particles 1 or 2 from the viewpoint of reliably preventing unnecessary aggregation, and is preferably 60 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less, relative to 100 parts by mass of aggregated particles 1 or 2 from the viewpoint of reducing residues in the toner.

[0087] [Process 2] In step 2, for example, the aggregated particles 1 or aggregated particles 2 obtained in step 1 are fused in an aqueous medium to obtain fused particles. Note that when simply described as "aggregated particles", it means the aggregated particles obtained in step 1 (aggregated particles 1 or aggregated particles 2).

[0088] Step 2 is a step in which an amphiphilic molecule having a naphthalene ring is added to the aggregated particles preferably obtained in step 1, and then the temperature is raised to fuse the particles, thereby obtaining fused particles. The amphiphilic molecule having a naphthalene ring is added for the purpose of improving the dispersion stability of the aggregated particles during fusion. The amphiphilic molecule having a naphthalene ring may be present at the time of aggregation in step 1, but it is preferable to add it fresh in step 2 before fusion.

[0089] [Amphiphilic molecules containing a naphthalene ring] The amphiphilic molecule having a naphthalene ring is an amphiphilic molecule having a surface active effect, and is preferably an anionic surfactant. Examples of amphiphilic molecules having a naphthalene ring include naphthalenesulfonates and naphthalenesulfonic acid-formaldehyde condensates. The naphthalenesulfonate is preferably an alkali metal salt of naphthalenesulfonic acid, more preferably sodium naphthalenesulfonate. The naphthalenesulfonic acid-formalin condensate is preferably a compound represented by the following formula (3).

[0090] [ka]

[0091] In formula (3), t represents an integer of preferably 2 or more and 200 or less, more preferably 6 or more and 100 or less, and further preferably 10 or more and 50 or less. M each independently represents a cation, and is a cation of an element selected from the group 1 elements and group 2 elements of the periodic table of elements; quaternary ammonium; and ammonium (NH + Among these, cations of elements in Group 1 of the periodic table of elements are preferred; cations of elements selected from lithium, sodium, and potassium are more preferred, and sodium cations are even more preferred. In addition, it is preferred that multiple M are the same cation. R represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a hydroxyl group, and is preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. In addition, other structural units may be included in the composition as long as the effect as a dispersion stabilizer is not impaired. Examples of other structural units include structural units formed from copolymerizable monomers such as alkyl naphthalene sulfonic acid and alkyl alcohol naphthalene sulfonic acid. The content of these structural units is preferably 30% by mass or less. The naphthalenesulfonic acid-formalin condensate is preferably a sodium salt of a naphthalenesulfonic acid-formalin condensate.

[0092] The weight average molecular weight of the naphthalenesulfonic acid-formalin condensate is preferably 500 or more, more preferably 1,500 or more, even more preferably 2,500 or more, and is preferably 40,000 or less, more preferably 20,000 or less, even more preferably 10,000 or less. The weight average molecular weight of the naphthalenesulfonic acid-formaldehyde condensate is measured by gel permeation chromatography (GPC).

[0093] The naphthalenesulfonic acid-formalin condensate can be produced by a known method, for example, by polycondensation using β-naphthalenesulfonic acid (salt) and an equivalent amount of formalin, and other components as necessary, such as sulfonic acids (salts) of β-methylnaphthalene, α-methylnaphthalene, acenaphthene, dibenzofuran, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, and the like. As the naphthalenesulfonic acid-formalin condensate, commercially available products may be used, and examples thereof include DEMOL N, DEMOL NL, DEMOL RN, DEMOL RN-L, DEMOL T, DEMOL T-45, DEMOL MS, DEMOL SN-B, DEMOL SS-L, and 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, and Labelin MN-P manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.; and IONET D-2 manufactured by Sanyo Chemical Industries, Ltd.

[0094] The amount of the amphiphilic molecule having a naphthalene ring added in step 2 is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, even more preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more, relative to 100 parts by mass of the aggregated particles, and is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, even more preferably 15 parts by mass or less, and even more preferably 12 parts by mass or less. In step 2, among the amphiphilic molecules added to aggregated particles 2, the amphiphilic molecules having a naphthalene ring are preferably 90% by mass or more, more preferably 95% by mass or more, and 100% by mass or less, and even more preferably 100% by mass.

[0095] In step 2, from the viewpoint of improving the fusibility of the aggregated particles, the aggregated particles are maintained at a temperature equal to or higher than the glass transition temperature of the resin having the highest glass transition temperature in the aggregated particles. From the viewpoint of improving the fusibility of the aggregated particles and improving the productivity of the toner, the holding temperature when fusing the aggregated particles is preferably at least 2° C. higher than the glass transition temperature of the resin having the highest glass transition temperature in the aggregated particles, more preferably at least 3° C. higher, even more preferably at least 5° C. higher, and is preferably not higher than 30° C. higher, more preferably not higher than 25° C. higher, even more preferably not higher than 20° C. higher. In this case, the time for which the temperature is maintained at or above the glass transition temperature of the resin having the highest glass transition temperature in the agglomerated particles is preferably 1 minute or more, more preferably 10 minutes or more, even more preferably 30 minutes or more, and is preferably 240 minutes or less, more preferably 180 minutes or less, even more preferably 120 minutes or less, even more preferably 90 minutes or less. It is preferable to maintain the temperature at the above temperature until the desired circularity is achieved.

[0096] The volume median particle size D of the fused particles obtained by fusion 50 is preferably 2 μm or more, more preferably 3 μm or more, even more preferably 4 μm or more, and is preferably 10 μm or less, more preferably 8 μm or less, even more preferably 7 μm or less.

[0097] The circularity of the fused particles obtained by fusion is preferably 0.955 or more, more preferably 0.960 or more, even more preferably 0.965 or more, and is preferably 0.990 or less, more preferably 0.985 or less, even more preferably 0.980 or less. The fusion is preferably terminated after the above-mentioned preferred circularity is reached. The circularity is measured by the method described in the Examples.

[0098] [Post-processing process] After the fusion step, a post-treatment step may be performed, and the fused particles are isolated to obtain toner particles. Since the fused particles obtained in the fusion step are present in an aqueous medium, it is preferable to first perform solid-liquid separation. For the solid-liquid separation, a suction filtration method or the like is preferably used. It is preferable to wash the solid-liquid separation product. In this case, it is preferable to remove the surfactant added, and therefore it is preferable to wash the product with an aqueous medium at a temperature below the cloud point of the surfactant. It is preferable to wash the product several times. Next, drying is preferably performed. Examples of the drying method include vacuum low-temperature drying, vibration-type fluidized bed drying, spray drying, freeze drying, and flash jet drying.

[0099] [Toner Particles] Volume median particle size of toner particles D 50 From the viewpoint of further improving the cleaning properties of the toner, the particle size is preferably 2 μm or more, more preferably 3 μm or more, even more preferably 4 μm or more, and is preferably 10 μm or less, more preferably 8 μm or less, even more preferably 7 μm or less.

[0100] The circularity of the toner particles is preferably 0.955 or more, more preferably 0.960 or more, even more preferably 0.965 or more, and is preferably 0.990 or less, more preferably 0.985 or less, even more preferably 0.980 or less.

[0101] From the viewpoint of improving the productivity of the toner, the CV value of the toner particles is preferably 10% or more, more preferably 15% or more, and even more preferably 18% or more, and from the viewpoint of obtaining high-quality images, it is preferably 35% or less, more preferably 30% or less, and even more preferably 25% or less. Volume median particle size of toner particles D 50 can be measured by the method described in the Examples.

[0102] [Toner for developing electrostatic images] The toner for developing electrostatic images of the present invention contains toner particles. The toner particles can be used as they are, but it is preferable to use the toner after adding a fluidizing agent or the like as an external additive to the surface of the toner particles.

[0103] [External additives] Examples of the external additive include inorganic fine particles 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 with two or more kinds. In addition, two or more kinds of hydrophobic silica having different particle sizes may be used. When the toner particles are surface-treated using an external additive, the amount of the external additive added is, relative to 100 parts by mass of the toner particles, preferably 1 part by mass or more, more preferably 2 parts by mass or more, even more preferably 3 parts by mass or more, and preferably 5 parts by mass or less, more preferably 4.5 parts by mass or less, even more preferably 4 parts by mass or less.

[0104] Toners are used for developing electrostatic images in electrophotographic printing. The toners can be used, for example, as one-component developers or mixed with a carrier to form two-component developers. EXAMPLES

[0105] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Each property value was measured and evaluated by the following methods. In the notation "alkylene oxide (X)" and the like, the number X in parentheses means the average number of moles of alkylene oxide added.

[0106] [Measurement method] The properties of the polyester resin, the resin particles, the toner, etc. were measured and evaluated by the following methods. [Softening point, crystallinity index, melting point and glass transition temperature of resin] (1) Softening point Using a flow tester "CFT-500D" (Shimadzu Corporation), 1 g of sample was heated at a temperature increase rate of 6°C / min, while applying a load of 1.96 MPa with the plunger, and extruding the sample 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 sample was weighed into an aluminum pan and cooled to 0°C at a rate of 10°C / min. The sample was then left to stand for 1 minute, and then heated to 180°C at a rate of 10°C / min to measure the amount of heat. The temperature of the peak with the largest peak area among the observed endothermic peaks was taken as the endothermic maximum peak temperature (1), and the crystallinity index was calculated by (softening point (°C)) / (endothermic maximum 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 to 200°C, and cooled from that temperature to 0°C at a rate of 10°C / min. The sample was then heated at a rate of 10°C / min, and the amount of heat was measured. Among the endothermic peaks observed, 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. In the case of an amorphous resin, when a peak was observed, the temperature of the 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 showing the maximum slope of the curve at the step and an extension of the baseline on the low temperature side of the step was taken as the glass transition temperature.

[0107] [Acid value of resin] The acid value of the resin was measured according to the neutralization titration method described in JIS K 0070: 1992. The measurement solvent was a mixed solvent of acetone and toluene (acetone:toluene=1:1 (volume ratio)).

[0108] [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 to 200°C, and then cooled from 200°C to 0°C at a rate of 10°C / min. The sample was then heated at a rate of 10°C / min, the amount of heat was measured, and the maximum endothermic peak temperature was taken as the melting point.

[0109] [Volume median particle diameter D of resin particles, colorant particles, and release agent particles 50 and CV value] (1) Measuring device: Laser diffraction type particle size measuring device "LA-920" (manufactured by Horiba Ltd.) (2) Measurement conditions: Put the sample dispersion in a measurement cell, add distilled water, and measure the volume median particle size D at a concentration where the absorbance is in the appropriate range. 50 The volume average particle diameter Dv was measured, and the CV value was calculated according to the following formula. CV value (%) = (Standard deviation of particle size distribution / Volume average particle size Dv) x 100

[0110] [Solid Content Concentration of Resin Particle Dispersion, Colorant Particle Dispersion, and Release Agent Particle Dispersion] Using an infrared moisture meter "FD-230" (Kett Electric Laboratory Co., Ltd.), the moisture content (mass%) of 5 g of the measurement sample was measured at a drying temperature of 150°C and measurement mode 96 (monitoring time 2.5 minutes, moisture content fluctuation range 0.05%). The solid content concentration was calculated according to the following formula. Solid concentration (mass%) = 100-moisture (mass%)

[0111] [Volume median particle diameter of agglomerated particles D 50 〕 Volume median particle size of agglomerated particles D 50 was measured as follows: Measuring instrument: "Coulter Multisizer (registered trademark) III" (manufactured by Beckman Coulter, Inc.) Aperture diameter: 50μm Analysis software: "Multisizer (registered trademark) III version 3.51" (Beckman Coulter, Inc.) Electrolyte: "Isoton (registered trademark) II" (manufactured by Beckman Coulter, Inc.) Measurement conditions: The sample dispersion is added to 100 mL of the electrolyte to adjust the concentration so that the particle size of 30,000 particles can be measured in 20 seconds. Then, 30,000 particles are measured again, and the volume median particle size D is calculated from the particle size distribution. 50 asked for.

[0112] [Circularity of fused particles] The circularity of the fused particles was measured under the following conditions. Measurement equipment: Flow-type particle image analyzer "FPIA-3000" (Sysmex Corporation) Preparation of dispersion: A dispersion of fused particles was prepared by diluting with deionized water to a solids concentration of 0.001 to 0.05% by mass. Measurement mode: HPF measurement mode

[0113] [Volume median particle size of toner particles D 50 and CV value] Volume median particle size of toner particles D 50 was measured as follows: The measurement device, aperture diameter, analysis software, and electrolyte were determined based on the volume median particle diameter D 50 The same one used in the measurement was used. Dispersion: Polyoxyethylene lauryl ether "EMULGEN (registered trademark) 109P" (manufactured by Kao Corporation, HLB (hydrophile-lipophile balance) = 13.6) was dissolved in the electrolyte to obtain a dispersion with a concentration of 5 mass %. Dispersion conditions: 10 mg of a measurement sample of dried toner particles was added to 5 mL of the dispersion liquid, and dispersed for 1 minute using an ultrasonic disperser. Thereafter, 25 mL of the electrolyte was added, and the mixture was further dispersed for 1 minute using an ultrasonic disperser to prepare a sample dispersion liquid. Measurement conditions: The sample dispersion is added to 100 mL of the electrolyte to adjust the concentration so that the particle size of 30,000 particles can be measured in 20 seconds. Then, 30,000 particles are measured and the volume median particle size D is calculated from the particle size distribution. 50 and volume average particle size D V asked for. The CV value (%) was calculated according to the following formula. CV value (%) = (Standard deviation of particle size distribution / Volume average particle size D V ) x 100

[0114] [Resin manufacturing] [Production of Polyester Resin A] Production Example A1 (Production of Resin A-1) The inside of a 10L four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple was replaced with nitrogen, and 3253g of propylene oxide (2.2) adduct of bisphenol A, 1003g of terephthalic acid, 24g of tin (II) di(2-ethylhexanoate), and 2.4g of gallic acid (3,4,5-trihydroxybenzoic acid) were added. The reaction system was heated to 235°C while stirring under a nitrogen atmosphere, and then maintained at 235°C for 5 hours. The pressure in the flask was then reduced and maintained at 8kPa for 1 hour. After that, the pressure was returned to atmospheric pressure, and the mixture was cooled to 160°C. While maintaining the temperature at 160°C, a mixture of 2139g of styrene, 535g of stearyl methacrylate, 107g of acrylic acid, and 321g of dibutyl peroxide was added dropwise to the reaction system over 3 hours. After that, the reaction system was kept at 160°C for 30 minutes, then heated to 200°C, and the pressure in the flask was further reduced and kept at 8kPa for 1 hour. After that, the pressure was returned to atmospheric pressure, and the mixture was cooled to 190°C, and 129g of fumaric acid, 94g of sebacic acid, 214g of trimellitic anhydride, and 2.4g of 4-tert-butylcatechol were added, and the temperature was raised to 210°C at 10°C / hr, and then the reaction was continued at 4kPa until the desired softening point, to obtain Resin A-1. The physical properties are shown in Table 1.

[0115] Production Example A2 (Production of Resin A-2) In a 20 L stainless steel kettle equipped with a nitrogen inlet tube, a dehydration tube, a stirrer and a thermocouple, the raw monomers of the polyester resin, except for trimellitic anhydride, shown in Table 1, were placed. The mixture was reacted at 230°C for 8 hours under a nitrogen atmosphere, and then reacted under a reduced pressure of 1.3 kPa to 2.0 kPa for 4 hours. After adding trimellitic anhydride, the mixture was reacted at 180°C until the desired softening point was reached, yielding resin A-2. The physical properties are shown in Table 1.

[0116] [Production of Polyester Resin B] Manufacturing Example B1 (Manufacturing of Resin B-1) Resin B-1 was obtained in the same manner as in Production Example A2, except that the raw material monomers for the polyester resin were changed as shown in Table 1. The physical property values ​​are shown in Table 1.

[0117] [Production of Composite Resin D] Manufacturing Example D1 (Manufacturing of Resin D-1) The inside of a 10L four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple was replaced with nitrogen, and 4313g of a propylene oxide (2.2) adduct of bisphenol A, 818g of terephthalic acid, 30g of tin (II) di(2-ethylhexanoate), and 3.0g of gallic acid (3,4,5-trihydroxybenzoic acid) were added. The reaction system was heated to 235°C under a nitrogen atmosphere while stirring, and then maintained at 235°C for 5 hours. The pressure in the flask was then reduced and maintained at 8kPa for 1 hour. After that, the pressure was returned to atmospheric pressure, and the mixture was cooled to 160°C. While maintaining the temperature at 160°C, a mixture of 2756g of styrene, 689g of stearyl methacrylate, 142g of acrylic acid, and 413g of dibutyl peroxide was added dropwise over 3 hours. The reaction system was then held at 160°C for 30 minutes, then heated to 200°C, and the pressure in the flask was further reduced and held at 8kPa for 1 hour. After that, the pressure was returned to atmospheric pressure, and the mixture was cooled to 190°C, 727g of succinic acid was added, and the mixture was heated to 210°C at 10°C / hr, and then reacted at 4kPa until the desired softening point was obtained, to obtain Resin D-1. The physical properties are shown in Table 1. Although resin D-1 is included in resin A, it is used to disperse the release agent, and therefore is referred to as "resin D-1" for convenience.

[0118] [Table 1]

[0119] [Production of Crystalline Polyester Resin C] Manufacturing Example C1 (Manufacturing of Resin C-1) The inside of a 10L four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer and a thermocouple was replaced with nitrogen, the raw material monomers of the polyester resin shown in Table 2 were added, and the reaction system was heated to 135°C while stirring, and then held at 135°C for 3 hours, and then heated from 135°C to 200°C over 10 hours. Then, 23g of di(2-ethylhexanoate)tin(II) was added to the reaction system, and the system was further held at 200°C for 1 hour, after which the pressure in the flask was reduced and the system was held under a reduced pressure of 8kPa for 1 hour to obtain Resin C-1, a crystalline polyester resin. The physical properties are shown in Table 2.

[0120] Production Examples C2 and C3 (Production of Resins C-2 and C-3) Resins C-2 and C-3 were obtained in the same manner as in Production Example C1, except that the alcohol component and the carboxylic acid component in Production Example C1 were changed to those shown in Table 2. The physical property values ​​are shown in Table 2.

[0121] [Table 2]

[0122] [Production of Resin Particle Dispersion] Production Example X1 (Production of Resin Particle Dispersion X-1) In a 2 L vessel equipped with a stirrer, a reflux condenser, a dropping funnel, a thermometer, and a nitrogen inlet tube, 100 g of Resin A-1 shown in Table 3 and 100 g of methyl ethyl ketone were placed and dissolved at 73° C. for 2 hours. A 5% by mass aqueous solution of sodium hydroxide was added to the resulting solution so that the degree of neutralization with respect to the acid value of Resin A-1 was 60 mol %, and the mixture was stirred for 30 minutes. Next, while maintaining the temperature at 73°C, 100 g of deionized water was added over 50 minutes while stirring at 200 r / min to cause phase inversion emulsification. While maintaining the temperature at 73°C, the methyl ethyl ketone was distilled off under reduced pressure to obtain a dispersion. Thereafter, while continuing to stir, the dispersion was cooled to 30°C, and deionized water was added so that the solid concentration was 20 mass%, to obtain resin particle dispersion X-1. The physical properties are shown in Table 3.

[0123] Production Examples X2 and Y1 to Y3 (Production of Resin Particle Dispersions X-2 and Y-1 to Y-3) Resin particle dispersions X-2 and Y-1 to Y-3 were obtained in the same manner as in Production Example X1, except that the resin in Production Example X1 was changed as shown in Table 3. The physical property values ​​are shown in Table 3.

[0124] Production Example Z1 (Production of Resin Particle Dispersion Z-1) 100 g of Resin B-1 and 100 g of methyl ethyl ketone were placed in a 3 L vessel equipped with a stirrer, a reflux condenser, a dropping funnel, a thermometer, and a nitrogen inlet tube, and dissolved for 2 hours at 73° C. A 5% by mass aqueous solution of sodium hydroxide was added to the resulting solution so that the degree of neutralization with respect to the acid value of Resin B-1 was 60 mol%, and the mixture was stirred for 30 minutes. Next, while maintaining the temperature at 73°C, 200 g of deionized water was added over 50 minutes while stirring at 200 r / min (circumferential speed 63 m / min) to cause phase inversion emulsification. While maintaining the temperature of the obtained solution at 73°C, methyl ethyl ketone was distilled off under reduced pressure to obtain a dispersion. Thereafter, while continuing to stir, the dispersion was cooled to 30°C, and deionized water was added so that the solid concentration became 20 mass%, thereby obtaining resin particle dispersion Z-1. The physical properties are shown in Table 3.

[0125] Production Example S1 (Production of Resin Particle Dispersion S-1) Resin particle dispersion S-1 was obtained in the same manner as in Production Example Z1, except that Resin B-1 was replaced with Resin D-1. The physical properties are shown in Table 3.

[0126] [Table 3]

[0127] [Preparation of Release Agent Particle Dispersion] Production Example W1 (Production of Release Agent Particle Dispersion W-1) Into a 1 L beaker, 120 g of deionized water, 86 g of resin particle dispersion S-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 to 95°C to melt the mixture, followed by stirring to obtain a molten mixture. The obtained molten mixture was dispersed for 20 minutes using an ultrasonic homogenizer "US-600T" (manufactured by Nippon Seiki Seisakusho Co., Ltd.) while maintaining the temperature at 90 to 95°C, and then cooled to room temperature (20°C). Deionized water was added to the obtained dispersion to adjust the solid content to 20 mass%, thereby obtaining release agent particle dispersion W-1. The volume median particle diameter D of the release agent particles in release agent particle dispersion W-1 was 50The diameter was 0.47 μm and the CV value was 27%.

[0128] Production Example W2 (Production of Release Agent Particle Dispersion W-2) A release agent particle dispersion W-2 was obtained in the same manner as in Production Example W1, except that the type of release agent was changed to Fischer-Tropsch wax "FNP-0090" (manufactured by Nippon Seiro Co., Ltd., melting point 90°C). 50 The diameter was 0.45 μm and the CV value was 28%.

[0129] [Preparation of Colorant Particle Dispersion] Production Example E1 (Production of Colorant Particle Dispersion E-1) In a 1 L beaker, 100 g of copper phthalocyanine pigment "ECB-301" (manufactured by Dainichiseika Chemicals Co., Ltd.), 35 g of polyoxyethylene (13) distyrenated phenyl ether "EMULGEN A-60" (manufactured by Kao Corporation, nonionic surfactant), and 300 g of deionized water were mixed and dispersed for 1 hour at room temperature (20°C) with a stirring blade rotation speed of 8000 rpm using a homomixer "TKAGI HOMOMIXER 2M-03" (manufactured by Tokushu Kika Kogyo Co., Ltd.), and then the mixture was treated for 15 passes at a pressure of 150 MPa using a "Microfluidizer M-110EH" (manufactured by Microfluidics Co., Ltd.), and then passed through a 200 mesh filter, and deionized water was added so that the solid concentration was 20 mass%, to obtain a colorant particle dispersion E-1. The volume median particle diameter D of the obtained colorant particles was 50 The thickness was 0.12 μm and the CV value was 21%.

[0130] The polyethylene glycol-polypropylene glycol-polyethylene glycol type triblock copolymers (triblock copolymers) used in the examples are shown in Table 4 below.

[0131] [Table 4]

[0132] [Toner manufacturing] Example 1 (Production of Toner 1) In a 3 L four-neck flask equipped with a dehydration tube, a stirrer, and a thermocouple, 350 g of resin particle dispersion X-1, 150 g of resin particle dispersion Y-1, 49 g of release agent particle dispersion W-1, 49 g of release agent particle dispersion W-2, 63 g of colorant particle dispersion E-1, and 2 g of triblock copolymer P-1 (ADEKA Pluronic F108, manufactured by ADEKA Corporation) were added and mixed at a temperature of 25° C. Next, while stirring the mixture, a solution obtained by dissolving 40 g of ammonium sulfate in 570 g of deionized water and adding a 4.8 mass % potassium hydroxide aqueous solution to adjust the pH to 8.2 was added dropwise over 10 minutes at 25° C., and the temperature was raised to 58° C. over 2 hours, and the volume median particle diameter D of the aggregated particles was measured. 50 The temperature was maintained at 58° C. until the particle size reached 6.5 μm, thereby obtaining a dispersion of aggregated particles 1. The obtained dispersion of aggregated particles 1 was cooled to 55° C., and while maintaining the temperature at 55° C., 48 g of resin particle dispersion Z-1 was added over 90 minutes, thereby obtaining a dispersion of aggregated particles 2 in which resin particles were aggregated to aggregated particles 1. To the obtained dispersion liquid of aggregated particles 2, 50 g of sodium salt of naphthalenesulfonic acid formalin condensate "Demol MS" (manufactured by Kao Corporation, effective concentration 20 mass%, weight average molecular weight 5000) and 1500 g of deionized water were added. Thereafter, the temperature was raised to 75°C over 1 hour, and the temperature was maintained at 75°C until the circularity reached 0.970, thereby obtaining a dispersion liquid of fused particles in which aggregated particles 2 were fused. The obtained dispersion of fused particles was cooled to 30°C, and the solid content was separated by suction filtration, washed with deionized water at 25°C, and then suction filtered at 25°C for 2 hours. Then, using a vacuum constant temperature dryer "DRV622DA" (manufactured by ADVANTEC), the solid content was vacuum dried at 33°C for 24 hours to obtain toner particles 1 having a core-shell structure. The physical properties of toner particles 1 are shown in Table 5. 100 parts by mass of toner particles 1, 2.5 parts by mass of hydrophobic silica "RY50" (manufactured by Nippon Aerosil Co., Ltd., number average particle size: 0.04 μm), and 1.0 part by mass of hydrophobic silica "Cabosil (registered trademark) TS720" (manufactured by Cabot Japan Co., Ltd., number average particle size: 0.012 μm) were placed in a Henschel mixer, stirred, and passed through a 150 mesh sieve to obtain toner 1. The physical properties of the obtained toner 1 are shown in Table 5.

[0133] [Toner Evaluation] The obtained toner 1 was evaluated as follows.

[0134] [Evaluation of electrostatic charge] (Amount of charge under normal temperature and humidity conditions) At a temperature of 25°C and a relative humidity of 50%, 2.1 g of toner and 27.9 g of silicone ferrite carrier (manufactured by Kanto Denka Kogyo Co., Ltd., average particle size: 40 μm) were placed in a 50 mL cylindrical polypropylene bottle (manufactured by Nikko Hansen Co., Ltd.) and mixed at 250 r / min using a ball mill. Immediately after mixing, the charge amount was measured under the following conditions using a "q / m-meter" (manufactured by Epping Co., Ltd.). The evaluation results are shown in Table 5. Mesh size: 635 mesh (opening: 24 μm, stainless steel) Soft blow: Blow pressure (1000V) ·Suction time: 90 seconds The charge amount is calculated by the following formula, and a larger absolute value indicates better chargeability. Charge amount (μC / g) = Total charge after 90 seconds (μC) / Amount of toner absorbed (g)

[0135] (Amount of charge in a high temperature and high humidity environment) After 10.0 g of the toner was left to stand in a thermostatic chamber at a temperature of 45° C. and a relative humidity of 70% for 72 hours, the toner was taken out and subjected to the same measurement as the charge amount measurement described above. The evaluation results are shown in Table 5.

[0136] [Evaluation of Fog] The toner was loaded onto a commercially available printer, "Microline (registered trademark) 5400" (manufactured by Oki Electric Industry Co., Ltd.), and an image with a print density of 1% was printed on high-quality paper, "J paper A4 size" (manufactured by Fuji Xerox Co., Ltd.), in an environment of a temperature of 45°C and a relative humidity of 70%. This was repeated to print a total of 1000 sheets, and then a blank sheet was printed, during which the printer was stopped midway through the blank sheet printing. The developing unit was removed from the printer, and "Scotch (registered trademark) Mending Tape 810" (manufactured by 3M Japan Ltd., width: 18 mm) was attached onto the photoconductor, and the toner on the photoconductor was peeled off with the tape. The tape peeled off from the photoreceptor and unused tape were attached to high-quality paper "J paper A4 size" (manufactured by Fuji Xerox Co., Ltd.), and the tape peeled off from the photoreceptor and unused tape were each measured using a colorimeter "SpectroEye" (manufactured by GretagMacbeth, light irradiation conditions: standard light source D50, observation field of view 2°, density standard DINNB, absolute white standard). The color difference (ΔE) between the tape peeled off from the photoreceptor and unused tape was taken as fog. The smaller the fog value, the better the image without fog. The evaluation results are shown in Table 5.

[0137] Examples 2 to 7 (Production of Toners 2 to 7) Toner particles 2 to 7 and toners 2 to 7 were obtained in the same manner as in Example 1, except that the triblock copolymer P-1 was changed to P-2 to P-7. Toner particles 2 to 7 and toners 2 to 7 were evaluated in the same manner as in Example 1. The evaluation results are shown in Table 5.

[0138] Examples 8 to 10 (Production of Toners 8 to 10) Toner particles 8 to 10 and toners 8 to 10 were obtained in the same manner as in Example 1, except that the resin particle dispersion was changed as shown in Table 5. Toner particles 8 to 10 and toners 8 to 10 were evaluated in the same manner as in Example 1. The evaluation results are shown in Table 5.

[0139] Comparative Examples 1 and 2 (Production of Toners 11 and 12) Toner particles 11 and 12, and toners 11 and 12 were obtained in the same manner as in Example 1, except that 1 g of nonionic surfactant G-1 (polyoxyethylene lauryl ether "EMULGEN 105" (manufactured by Kao Corporation)) or 6.7 g of anionic surfactant G-2 (15 mass % sodium dodecylbenzenesulfonate aqueous solution "NEOPELEX G-15" (manufactured by Kao Corporation)) was used instead of triblock copolymer P-1. Toner particles 11 and 12, and toners 11 and 12 were also evaluated in the same manner as in Example 1. The evaluation results are shown in Table 5.

[0140] [Table 5]

[0141] From the above results, it was possible to obtain toner particles having a narrow particle size distribution by adding a block copolymer of polyethylene glycol and polypropylene glycol in the toner manufacturing process of Examples 1 to 10. Furthermore, the toners of Examples 1 to 10 were able to maintain a high charge amount even after storage in a high-temperature, high-humidity environment, so that the occurrence of fogging was suppressed even in a high-temperature, high-humidity environment. In contrast, toner particles having a narrow particle size distribution could not be obtained in Comparative Example 1 using polyoxyethylene lauryl ether and Comparative Example 2 using sodium dodecylbenzenesulfonate. Furthermore, the toners of Comparative Examples 1 and 2 were able to produce a large amount of fogging in a high-temperature, high-humidity environment because the charge amount decreased after storage in a high-temperature, high-humidity environment.

Claims

1. A method for manufacturing toner for electrostatic image development, comprising the following steps 1 and 2. Step 1: A process to obtain aggregated particles by agglomerating resin particles containing crystalline polyester resin in an aqueous medium in the presence of a block copolymer of polyethylene glycol and polypropylene glycol. Step 2: A step to obtain fused particles by fusing the aggregated particles obtained in Step 1.

2. A method for producing a toner for electrostatic image developing according to claim 1, wherein the block copolymer of polyethylene glycol and polypropylene glycol is a polyethylene glycol-polypropylene glycol-polyethylene glycol type triblock copolymer.

3. A method for producing electrostatic image developing toner according to claim 1, wherein the content of polyethylene glycol segments in the block copolymer of polyethylene glycol and polypropylene glycol is 5% by mass or more and 90% by mass or less.

4. The method for producing electrostatic image developing toner according to claim 1, wherein step 1 is a step of agglomerating resin particles containing a crystalline polyester resin and an amorphous polyester resin in an aqueous medium in the presence of a block copolymer of polyethylene glycol and polypropylene glycol to obtain agglomerated particles.

5. The method for producing electrostatic image developing toner according to claim 1, wherein step 2 is a step of heating and fusing the aggregated particles obtained in step 1 in the presence of an amphiphilic molecule having a naphthalene ring to obtain fused particles.

6. A method for producing a toner for electrostatic image developing according to any one of claims 1 to 5, wherein the amount of block copolymer of polyethylene glycol and polypropylene glycol used in step 1 is 0.5 parts by mass or more and 10 parts by mass or less per 100 parts by mass of crystalline polyester resin.