Toner manufacturing method

Abstract

To provide a toner manufacturing method which is excellent in transferability under high temperature and high humidity.SOLUTION: A toner manufacturing method includes a step of coagulating and fusing resin particles containing an amorphous composite resin and a crystalline resin in an aqueous medium. The amorphous composite resin is a composite resin obtained by coupling a styrene acrylic resin unit and a polyester resin unit through a covalent bond. A styrene acrylic resin (A) constituting the styrene acrylic resin unit contains 40 mass% or more of a (meth)acrylic monomer-derived constitutional unit. The acid value of the styrene acrylic resin (A) is 60 mgKOH / g or more. The polyester resin (B) constituting the polyester resin unit is a polycondensate of an alcohol component containing aliphatic diol and a carboxylic acid component. The crystalline resin is a crystalline polyester-based resin.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for producing a toner used in developing a latent image formed in an electrophotographic method, an electrostatic recording method, an electrostatic printing method or the like. [Background technology]

[0002] In recent years, in the field of electrophotography, with the development of electrophotographic systems, there is a demand for the development of toners for developing electrostatic images that can meet the demands of higher image quality and faster printing. In addition, with the diversification of print media, there is a growing demand for electrophotographic printing on print media other than paper. Therefore, in order to realize the versatility of fixation to each print media and the realization of higher image quality, a toner with excellent low-temperature fixability and transferability is required. It is known that, particularly under high temperature and humidity conditions, a large amount of moisture is adsorbed to the toner surface, increasing its mobility, which in turn leads to rapid charge leakage from the toner surface, reducing the toner's charge, and causing the toner to remain on the electrostatic image carrier without being transferred to the printing medium, resulting in reduced transferability.

[0003] Patent Document 1 discloses an electrophotographic toner obtained by a method including a step of granulating a raw material containing a binder resin in an aqueous medium, in which the binder resin contains a composite resin containing a condensation polymerization resin and a styrene resin, and the condensation polymerization resin is a resin obtained by condensation polymerization of an alcohol component containing an aliphatic polyhydric alcohol (alcohol A) having two or more secondary carbon atoms bonded to a hydroxyl group, and a carboxylic acid component.

[0004] Patent Document 2 discloses a binder resin for toner containing a composite resin in which a styrene-acrylic resin unit and a polyester-based resin unit are bonded via a covalent bond, in which the acid value of the styrene-acrylic resin (A) constituting the styrene-acrylic resin unit is 40 mgKOH / g or more. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2010-107675 A [Patent Document 2] JP 2021-107920 A Summary of the Invention [Problem to be solved by the invention]

[0006] In order to obtain a toner with excellent low-temperature fixing properties, a toner is produced by an emulsion aggregation method and a crystalline polyester resin is incorporated into the toner. However, since highly hydrophobic crystalline polyester resin is difficult to encapsulate in toner particles, and is easily exposed to the particle surface, particularly under high temperature and high humidity conditions, there is a problem that the transferability of the resulting toner particles is impaired. The present invention relates to a method for producing a toner having excellent transferability even under high temperature and high humidity conditions. [Means for solving the problem]

[0007] The present inventors have found that in a toner manufacturing method including a step of aggregating and fusing resin particles containing an amorphous composite resin and a crystalline resin in an aqueous medium, the amorphous composite resin is a composite resin in which an aliphatic diol-based amorphous polyester resin, which is advantageous for obtaining a toner having excellent transferability even under harsh conditions of high temperature and high humidity, and a styrene acrylic resin unit are bonded via a covalent bond, and the content of constituent units derived from a (meth)acrylic monomer that constitutes the styrene acrylic resin unit of the composite resin is at least a predetermined amount and has an acid value of at least a predetermined value, thereby making it possible to encapsulate a crystalline polyester resin, which is a crystalline resin that provides a toner with excellent low-temperature fixing ability, in the toner particles.

[0008] That is, the present invention relates to the following [1]. [1] A method for producing a toner, comprising a step of aggregating and fusing resin particles containing an amorphous composite resin and a crystalline resin in an aqueous medium, the amorphous composite resin is a composite resin in which a styrene-acrylic resin unit and a polyester resin unit are bonded via a covalent bond, the styrene acrylic resin (A) constituting the styrene acrylic resin unit contains 40 mass% or more of a structural unit derived from a (meth)acrylic monomer, and the acid value of the styrene acrylic resin (A) is 60 mgKOH / g or more; the polyester resin (B) constituting the polyester resin unit is a polycondensate of an alcohol component containing an aliphatic diol and a carboxylic acid component, The method for producing a toner, wherein the crystalline resin is a crystalline polyester resin. Effect of the Invention

[0009] According to the present invention, it is possible to provide a method for producing a toner that exhibits excellent transferability even under high temperature and high humidity conditions. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [Toner manufacturing method] The toner production method of the present invention is a toner production method including a process of aggregating and fusing resin particles containing an amorphous composite resin and a crystalline resin which is a crystalline polyester resin in an aqueous medium. The amorphous composite resin is a composite resin in which a styrene-acrylic resin unit and a polyester-acrylic resin unit are bonded via a covalent bond, in which a styrene-acrylic resin (A) constituting the styrene-acrylic resin unit contains 40 mass% or more of constituent units derived from a (meth)acrylic monomer and the acid value of the styrene-acrylic resin (A) is 60 mgKOH / g or more, and a polyester resin (B) constituting the polyester resin unit is a polycondensate of an alcohol component containing an aliphatic diol and a carboxylic acid component. The toner produced by the production method of the present invention exhibits excellent transferability under high temperature and high humidity conditions, despite containing a crystalline resin.

[0011] The reason why the present invention has an effect is not clear, but is thought to be as follows. Amorphous polyester resins containing structural units derived from aliphatic diols, which are advantageous for obtaining toners with excellent transferability even under harsh conditions such as high temperature and high humidity, are highly hydrophilic due to the inclusion of many low molecular weight components even when the degree of polymerization is increased. Therefore, in the production of toners by emulsion aggregation, many low molecular weight components of hydrophilic amorphous polyester resins are present on the surface during aggregation in water. If a crystalline polyester resin, which is advantageous for obtaining toners with excellent low-temperature fixing properties, is added to the toners, the affinity between hydrophilic particles containing amorphous polyester resins and highly hydrophobic crystalline polyester resins is poor, making it difficult to stably hold the crystalline polyester resin in the aggregated particles, and the aggregation control becomes unstable, so that the crystalline polyester resin cannot be encapsulated in the toner particles, resulting in a problem that the transferability of the obtained toner particles is not sufficient. In response to this, in the present invention, it has been discovered that the above-mentioned problems can be solved by using an amorphous composite resin obtained by covalently bonding a polyester resin (B) containing a structural unit derived from an aliphatic diol and a styrene-acrylic resin (A) having 40 mass% or more of structural units derived from a (meth)acrylic monomer and an acid value of 60 mgKOH / g or more. The styrene acrylic resin (A) contains 40% by mass or more of a constituent unit derived from a (meth)acrylic monomer, and therefore has high mobility and a large number of acid groups, so that the reactivity with the low molecular weight component of the polyester resin (B) is improved and the resin is preferentially composited. Since the constituent unit derived from a (meth)acrylic monomer contained in the composite resin obtained has a high affinity with the crystalline polyester resin, when producing resin particles containing an amorphous composite resin and a crystalline resin, the crystalline polyester resin, which is a crystalline resin, can be stably encapsulated in the resin particles. As a result, the dispersibility of the crystalline polyester resin in the amorphous composite resin is improved, and when the resin particles are aggregated in an aqueous medium, aggregation control is facilitated, and toner particles with a narrow particle size distribution are obtained, and it is considered that a toner having good transferability under high temperature and high humidity conditions is obtained.

[0012] The definitions of various terms used in this specification are given below. The "polyester resin" may include a polyester resin that has been modified to such an extent that its properties are not substantially impaired. Examples of modified polyester resins include urethane-modified polyester resins in which a polyester resin is modified with a urethane bond, and epoxy-modified polyester resins in which a polyester resin is modified with an epoxy bond. "Bisphenol A" means 2,2-bis(4-hydroxyphenyl)propane. The carboxylic acid components of polyester resins include not only the compounds themselves, but also anhydrides that decompose during the reaction to produce carboxylic acids, and alkyl esters of each carboxylic acid (alkyl groups having 1 to 3 carbon atoms). 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. "(Meth)acrylic acid" means at least one selected from acrylic acid and methacrylic acid. The term "binder resin" refers to a binder resin component including a composite resin in a toner.

[0013] A method for producing a toner according to an embodiment of the present invention includes a step of aggregating and fusing resin particles containing an amorphous composite resin and a crystalline resin in an aqueous medium. The resin particles can be obtained, for example, by a phase inversion emulsification method using an amorphous resin and a crystalline resin, as described below. The present invention will be described below by taking this embodiment as an example.

[0014] [Process for agglomerating resin particles] In the step of aggregating the resin particles, the resin particles containing the amorphous composite resin and the crystalline resin are aggregated in an aqueous medium to obtain aggregated particles 1. Here, 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 resin particle dispersion containing the resin particles with a colorant particle dispersion containing colorant particles containing a colorant and / or a release agent particle dispersion containing release agent particles containing a release agent to aggregate these particles. It is more preferable that the resin particle dispersion, the colorant particle dispersion, and the release agent particle dispersion are an aqueous dispersion of resin particles, an aqueous dispersion of colorant particles, and an aqueous dispersion of release agent particles, respectively.

[0015] <Amorphous composite resin> The amorphous composite resin is a resin in which a styrene acrylic resin (A) constituting a styrene acrylic resin unit and a polyester resin (B) constituting a polyester resin unit are bonded via a covalent bond, and from the viewpoint of improving the transferability of the toner under high temperature and high humidity conditions, the styrene acrylic resin (A) contains 40 mass % or more of a constituent unit derived from a (meth)acrylic monomer and has an acid value of 60 mgKOH / g or more.

[0016] [Styrene acrylic resin (A)] (Raw material monomer (a)) The styrene-acrylic resin (A) constitutes a styrene-acrylic resin unit of an amorphous composite resin from the viewpoint of improving the transferability of a toner under high temperature and high humidity conditions, and is an addition polymer of raw material monomer (a) containing a styrene compound and a (meth)acrylic monomer.

[0017] Examples of styrene-based compounds include styrene and styrene derivatives such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-chlorostyrene, and vinylnaphthalene, and preferred are styrene and α-methylstyrene.

[0018] Examples of (meth)acrylic monomers include (meth)acrylic acid and (meth)acrylic acid derivatives such as acrylic acid, methacrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, amyl (meth)acrylate, cyclohexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, 2-ethylhexyl (meth)acrylate, stearyl (meth)acrylate, methoxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, glycidyl (meth)acrylate, 2-chloroethyl (meth)acrylate, phenyl (meth)acrylate, 2-(dimethylamino)ethyl (meth)acrylate, 2-(diethylamino)ethyl (meth)acrylate, and α-chloromethyl acrylate. Among these, the (meth)acrylic monomer preferably contains (meth)acrylic acid and an alkyl ester of (meth)acrylic acid having 1 to 6 carbon atoms, more preferably contains (meth)acrylic acid, methyl (meth)acrylate, and n-butyl (meth)acrylate, and even more preferably contains acrylic acid, methyl methacrylate, and n-butyl acrylate.

[0019] The raw material monomer (a) may contain other monomers in addition to the styrene compound and the (meth)acrylic monomer. Examples of other monomers include ethylenically unsaturated monoolefins such as ethylene, propylene, butylene, and isobutylene; diolefins such as butadiene; halovinyls such as vinyl chloride, vinyl bromide, and vinyl fluoride; vinyl esters such as vinyl acetate, vinyl propionate, vinyl formate, and vinyl caproate; vinyl ethers such as vinyl methyl ether; vinylidene halides such as vinylidene chloride; and N-vinyl compounds such as N-vinylpyrrole and N-vinylpyrrolidone.

[0020] The content of the (meth)acrylic monomer in the raw material monomer (a) constituting the styrene acrylic resin (A) or the content of the constituent unit derived from the (meth)acrylic monomer in the styrene acrylic resin (A) constituting the styrene acrylic resin unit is 40% by mass or more, preferably 45% by mass or more, more preferably 50% by mass or more, and preferably 98% by mass or less, more preferably 96% by mass or less, and even more preferably 94% by mass or less, from the viewpoint of improving the transferability of the toner under high temperature and high humidity conditions. The content of the styrene compound in the raw material monomer (a) constituting the styrene acrylic resin (A) or the content of the structural unit derived from the styrene compound in the styrene acrylic resin (A) constituting the styrene acrylic resin unit is, from the viewpoint of improving the transferability of the toner under high temperature and high humidity conditions, preferably 2 mass % or more, more preferably 4 mass % or more, even more preferably 6 mass % or more, and is 60 mass % or less, preferably 55 mass % or less, more preferably 50 mass % or less.

[0021] The total content of the styrene compound and the (meth)acrylic monomer in the raw material monomer (a) constituting the styrene acrylic resin (A), or the total content of the constituent units derived from the styrene compound and the constituent units derived from the (meth)acrylic monomer in the styrene acrylic resin (A) constituting the styrene acrylic resin unit, is preferably 90% by mass or more, more preferably 95% by mass or more, even more preferably 99% by mass or more, and is 100% by mass or less, even more preferably 100% by mass, from the viewpoint of improving the transferability of the toner under high temperature and high humidity conditions.

[0022] (Production of Resin (A)) In the present invention, the styrene acrylic resin (A) constituting the styrene acrylic resin unit is preferably polymerized in the absence of the polyester resin (B) constituting the polyester resin unit by a polymerization system independent of the polymerization system of the raw material monomer (b) constituting the polyester resin (B), from the viewpoint of controlling the molecular weight, molecular weight distribution, and copolymerizability of the monomer and improving the transferability of the toner under high temperature and high humidity conditions. From the above viewpoint, the polymerization method of the styrene acrylic resin (A) may be a polymerization method capable of controlling the molecular weight, molecular weight distribution, and copolymerizability of the monomer, such as a bulk polymerization method, a solution polymerization method, a suspension polymerization method, or an emulsion polymerization method.

[0023] From the viewpoint of ease of control of the molecular weight, molecular weight distribution, and copolymerizability of the monomers, the styrene-acrylic resin (A) is preferably formed by the following step I. Step I: A step of obtaining a styrene-acrylic resin (A) by polymerizing a raw material monomer (a) in an independent polymerization system separate from the polymerization system of the raw material monomer (b) constituting the polyester resin (B) in the absence of the polyester resin (B) constituting the polyester resin unit.

[0024] From the viewpoint of ease of control of molecular weight, molecular weight distribution, and copolymerizability of monomers, the styrene-acrylic resin (A) is preferably formed by bulk polymerization or solution polymerization, more preferably by bulk polymerization. That is, the polymerization of the raw material monomer (a) in step I is preferably bulk polymerization or solution polymerization, more preferably bulk polymerization.

[0025] In the present invention, the term "bulk polymerization" refers to addition polymerization carried out under conditions in which a solvent is substantially not present in the reaction system, that is, under solvent-free conditions. In the bulk polymerization (when the polymerization in step I is bulk polymerization), a radical generator may be used. Examples of the radical generator include peroxides such as di-tert-butyl peroxide, persulfates such as sodium persulfate, and azo compounds such as 2,2'-azobis(2,4-dimethylvaleronitrile). From the viewpoint of controlling the molecular weight, molecular weight distribution, and copolymerizability and further improving the transferability of the toner under high temperature and high humidity conditions, the concentration of the radical generator in the bulk polymerization is preferably 7% by mass or less, more preferably 5% by mass or less, even more preferably 2% by mass or less, even more preferably 1% by mass or less, even more preferably 0.5% by mass or less, and even more preferably 0% by mass, relative to the total amount of the raw material monomers (a) of the styrene acrylic resin (A), taken as 100% by mass, in other words, it is preferable to carry out the polymerization under catalyst-free conditions.

[0026] Bulk polymerization (when the polymerization in step I is bulk polymerization) is preferably carried out at high temperature under pressure equal to or higher than normal pressure, and continuous bulk polymerization at high temperature and high pressure is more preferred. In the present invention, the pressurized state refers to a state in which the contents of a sealed container such as an autoclave are heated to a temperature equal to or higher than the boiling point under normal pressure. Under high temperature and pressure equal to or higher than normal pressure, radicals generated by the thermal initiation reaction of the raw material monomer (a) function as a polymerization initiator, so that addition polymerization can be carried out even under conditions in which the amount of the radical generator is relatively small, and a styrene-acrylic resin (A) having a narrow molecular weight distribution can be obtained. Furthermore, in the case of continuous bulk polymerization, it is possible to control not only the molecular weight distribution but also the monomer composition distribution, and to obtain a styrene-acrylic resin (A) having a narrower and more uniform monomer composition distribution, thereby further improving the transferability of the toner under high temperature and high humidity conditions. From the above viewpoint, the temperature of the bulk polymerization is preferably 160° C. or higher and preferably 350° C. or lower.

[0027] In the present invention, the term "solution polymerization" refers to addition polymerization carried out under conditions in which a solvent is present in the reaction system. The polymer produced may be dissolved in the solvent, or may precipitate without being dissolved in the solvent. In the solution polymerization, the raw material monomer (a) is preferably subjected to addition polymerization by heating together with a polymerization initiator, a polymerization chain transfer agent, etc. in a solvent. Examples of the polymerization initiator include peroxides such as dibutyl peroxide, persulfates such as sodium persulfate, and azo compounds such as 2,2'-azobis(2,4-dimethylvaleronitrile). The amount of the polymerization initiator to be added is not particularly limited, but is preferably 0.5 parts by mass or more and preferably 30 parts by mass or less based on 100 parts by mass of the total amount of the raw material monomers (a). Examples of the polymerization chain transfer agent include mercaptans such as 2-mercaptoethanol and 3-mercaptopropionic acid. The amount of the polymerization chain transfer agent to be added is not particularly limited, but is preferably 0.01 parts by mass or more and preferably 10 parts by mass or less based on 100 parts by mass of the total amount of the raw material monomers (a). In the case of solution polymerization, after the completion of the polymerization reaction, the produced polymer may be isolated and purified by a known method such as reprecipitation from the reaction solution or distillation of the solvent.

[0028] (Physical properties of styrene acrylic resin (A)) From the viewpoint of further improving the transferability of the toner under high temperature and high humidity conditions, the weight average molecular weight of the styrene acrylic resin (A) is preferably 3,000 or more, more preferably 5,000 or more, and even more preferably 7,000 or more, and is preferably 200,000 or less, more preferably 100,000 or less, even more preferably 50,000 or less, even more preferably 30,000 or less, and even more preferably 20,000 or less. The weight average molecular weight of the styrene-acrylic resin (A) can be adjusted by the polymerization temperature and polymerization time.

[0029] From the viewpoint of further improving the transferability of the toner under high temperature and high humidity conditions, the softening point of the styrene-acrylic resin (A) is preferably 85° C. or higher, more preferably 90° C. or higher, even more preferably 100° C. or higher, and is preferably 160° C. or lower, more preferably 140° C. or lower, even more preferably 120° C. or lower. From the viewpoint of further improving the transferability of the toner under high temperature and high humidity conditions, the glass transition temperature of the styrene-acrylic resin (A) is preferably 40° C. or higher, more preferably 45° C. or higher, even more preferably 50° C. or higher, and is preferably 120° C. or lower, more preferably 90° C. or lower, even more preferably 75° C. or lower. Among these, it is more preferable that the styrene acrylic resin (A) constituting the styrene acrylic resin unit has a glass transition temperature of 50°C or higher and a softening point of 100°C or higher, from the viewpoint of further improving the transferability of the toner under high temperature and high humidity conditions.

[0030] The acid value of the styrene acrylic resin (A) is, from the viewpoint of forming a composite with the polyester resin (B) constituting the polyester resin unit, and from the viewpoint of improving the transferability of the toner under high temperature and high humidity conditions, 60 mgKOH / g or more, preferably 65 mgKOH / g or more, more preferably 70 mgKOH / g or more, and is preferably 300 mgKOH / g or less, more preferably 250 mgKOH / g or less, even more preferably 200 mgKOH / g or less, even more preferably 150 mgKOH / g or less, and even more preferably 100 mgKOH / g or less.

[0031] The weight average molecular weight, softening point, glass transition temperature, and acid value of the styrene-acrylic resin (A) can be measured by the methods described in the Examples. When two or more kinds of styrene-acrylic resins (A) are used in combination, the softening point, glass transition temperature and acid value of the mixture thereof preferably fall within the above-mentioned ranges.

[0032] [Polyester resin (B)] The polyester resin (B) constitutes the polyester resin unit of the amorphous composite resin, and is a polycondensation product of an alcohol component (b-al) containing an aliphatic diol and a carboxylic acid component (b-ac).

[0033] (Alcohol content (b-al)) Examples of the aliphatic diol contained in the alcohol component (b-al) include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,4-pentanediol, 1,5-pentanediol, 2,4-pentanediol, 1,2-hexanediol, 1,5-hexanediol, 2,5-hexanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, 1,14-tetradecanediol, 1,16-hexadecanediol, 3,3-dimethyl-1,2-butanediol, and neopentyl glycol (2,2-dimethyl-1,3-propanediol). Among these, the alcohol component (b-al) preferably contains an aliphatic diol having from 2 to 6 carbon atoms, and more preferably contains one or more selected from 1,2-propanediol, 2,3-butanediol, and neopentyl glycol. The alcohol component (b-al) may contain other alcohols in addition to the aliphatic diols, as long as the effects of the present invention are not impaired. Examples of other alcohols include diols such as aromatic diols and alicyclic diols, and polyhydric alcohols having three or more hydric groups.

[0034] Examples of the aromatic diol include alkylene oxide adducts of aromatic diols. Examples of the alicyclic diol include 1,4-cyclohexanedimethanol, hydrogenated bisphenol A, 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 the trihydric or higher polyhydric alcohol include glycerin, pentaerythritol, trimethylolpropane, sorbitol, and sorbitan. The other alcohols may be used alone or in combination of two or more.

[0035] From the viewpoint of further improving the transferability of the toner under high temperature and high humidity conditions, the content of the aliphatic diol in the alcohol component (b-al) is preferably 90 mol % or more, more preferably 95 mol % or more, even more preferably 98 mol % or more, and preferably 100 mol % or less, even more preferably 100 mol %.

[0036] (Carboxylic acid component (b-ac)) Examples of the carboxylic acid component (b-ac) include dicarboxylic acids and trivalent or higher polycarboxylic acids.

[0037] Dicarboxylic acids include, for example, aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and alicyclic dicarboxylic acids. The 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 aromatic dicarboxylic acids include phthalic acid, terephthalic acid, and isophthalic acid. Among these, terephthalic acid and isophthalic acid are preferred. Examples of aliphatic dicarboxylic acids include oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, pentanedioic acid, adipic acid, sebacic acid, dodecanedioic acid, azelaic acid, and succinic acid substituted with an aliphatic hydrocarbon group having from 1 to 20 carbon atoms. Examples of succinic acid substituted with an aliphatic hydrocarbon group having 1 to 20 carbon atoms include n-dodecenylsuccinic acid, isododecenylsuccinic acid, n-dodecylsuccinic acid, isododecylsuccinic acid, n-octenylsuccinic acid, n-octylsuccinic acid, isooctylsuccinic acid, and isooctylsuccinic acid. An example of the alicyclic dicarboxylic acid is cyclohexanedicarboxylic acid.

[0038] Examples of trivalent or higher polyvalent carboxylic acids include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, and pyromellitic acid.

[0039] Among these, the carboxylic acid component (b-ac) preferably contains one or more aromatic dicarboxylic acids, and more preferably contains one or more aromatic dicarboxylic acids selected from terephthalic acid and isophthalic acid. From the viewpoint of further improving the transferability of the toner under high temperature and high humidity conditions, the amount of the aromatic dicarboxylic acid in the carboxylic acid component (b-ac) is preferably 90 mol % or more, more preferably 95 mol % or more, even more preferably 98 mol % or more, and is preferably 100 mol % or less, even more preferably 100 mol %.

[0040] The carboxylic acid component (b-ac) may appropriately contain a polyvalent carboxylic acid having three or more valences in order to control the degree of polymerization of the resin. The trivalent or higher polyvalent carboxylic acid may be used in an amount of preferably 0.2% by mass or more and 30% by mass or less based on the total amount of the raw material monomers (b) of the polyester resin (B).

[0041] The equivalent ratio of the carboxyl group (COOH group) of the carboxylic acid component (b-ac) to the hydroxyl group (OH group) of the alcohol component (b-al) [COOH group / OH group] 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.

[0042] (Production of Resin (B)) The resin (B) is preferably produced, for example, by a polycondensation reaction of a raw material monomer (b) containing an alcohol component (b-al) and a carboxylic acid component (b-ac). From the viewpoint of further improving the transferability of the toner under high temperature and high humidity conditions, the polycondensation reaction is more preferably carried out according to the following step I'. Step I': A step of obtaining a polyester resin (B) by polymerizing a raw material monomer (b) in a polymerization system independent of the polymerization system of the raw material monomer (a) constituting the styrene acrylic resin (A) constituting the styrene acrylic resin unit in the absence of the styrene acrylic resin (A) constituting the styrene acrylic resin unit.

[0043] The polycondensation reaction in step I' may be carried out, as necessary, using an esterification catalyst such as tin(II) di(2-ethylhexanoate), dibutyltin oxide, titanium diisopropylate bistriethanolamine, etc., in an amount of 0.01 part by mass or more and 5 parts by mass or less relative to 100 parts by mass of the total amount of raw material monomer (b); or an esterification promoter such as gallic acid (equivalent to 3,4,5-trihydroxybenzoic acid), etc., in an amount of 0.001 part by mass or more and 0.5 part by mass or less relative to 100 parts by mass of the total amount of raw material monomer (b). In addition, when a monomer having an unsaturated bond such as fumaric acid is used in the polycondensation reaction in step I', a radical polymerization inhibitor may be used, if necessary, in an amount of preferably 0.001 to 0.5 parts by mass relative to 100 parts by mass of the total amount of the raw material monomer (b). An example of the radical polymerization inhibitor is 4-tert-butylcatechol. The temperature of the polycondensation reaction in step I' is preferably 120° C. or higher, more preferably 150° C. or higher, even more preferably 170° C. or higher, and is preferably 260° C. or lower, more preferably 240° C. or lower. The polycondensation reaction may be carried out in an inert gas atmosphere.

[0044] [Method of manufacturing amorphous composite resin] In the amorphous composite resin, a styrene-acrylic resin (A) constituting the styrene-acrylic resin unit and a polyester resin (B) constituting the polyester resin unit are bonded via a covalent bond. The method for producing the amorphous composite resin is, from the viewpoint of further improving the transferability of the toner under high temperature and high humidity conditions, Step II: A step of bonding the styrene-acrylic resin (A) obtained in Step I with a polyester resin (B) via a covalent bond to obtain a binder resin for toner containing the amorphous composite resin; It is preferred that the compound contains The production of the styrene-acrylic resin (A) in the step I is as described above.

[0045] From the viewpoint of further improving the transferability of the toner under high temperature and high humidity conditions, the method for producing the amorphous composite resin preferably further includes the above-mentioned step I'. The production of the polyester resin (B) in the step I' is as described above.

[0046] In the present invention, when the step I' is included, the step II is preferably a step of obtaining a binder resin for toner containing the amorphous composite resin by bonding the styrene acrylic resin (A) obtained in the step I and the polyester resin (B) obtained in the step I' through a covalent bond formed by a polymer reaction. That is, the polymerization reaction in the step II is preferably a condensation reaction of the styrene acrylic resin (A) and the polyester resin (B) from the viewpoint of making the complex sufficient and further improving the transferability of the toner under high temperature and high humidity. As a result, the styrene acrylic resin (A) and the polyester resin (B) are bonded through an ester bond, which is a covalent bond, and are composited. The condensation reaction may be a condensation reaction between a carboxy group of the styrene acrylic resin (A) and a hydroxy group of the polyester resin (B), or a condensation reaction between a hydroxy group of the styrene acrylic resin (A) and a carboxy group of the polyester resin (B).

[0047] In step II, from the viewpoint of making the composite sufficient and further improving the transferability of the toner under high temperature and high humidity, the composite of the styrene acrylic resin (A) and the polyester resin (B) is preferably carried out by forming a covalent bond via a compound (hereinafter also referred to as a "bireactive compound") that can react with both the raw material monomer (a) constituting the resin (A) and the raw material monomer (b) constituting the resin (B). That is, step II is preferably a step of forming a covalent bond via a structural unit derived from a bireactive compound contained in either the styrene acrylic resin (A) or the polyester resin (B) to obtain a binder resin for toner containing the amorphous composite resin, and more preferably a step of forming a covalent bond by a polymer reaction between the styrene acrylic resin (A) and the polyester resin (B) via a structural unit derived from a bireactive compound contained in the styrene acrylic resin (A) to obtain a binder resin for toner containing the amorphous composite resin.

[0048] As the bireactive compound, from the viewpoint of achieving sufficient complexation and further improving the transferability of the toner under high temperature and high humidity conditions, an ethylenically unsaturated monocarboxylic acid is preferable, and an acrylic acid is more preferable. The bireactive compound is preferably introduced into the polymer skeleton as a raw material monomer of either the styrene acrylic resin (A) or the polyester resin (B) before compounding, and then compounded with the other resin via the bireactive compound, and from the viewpoint of sufficient compounding, it is more preferable to introduce it into the polymer skeleton as the raw material monomer (a) of the styrene acrylic resin (A) before compounding, and then compounded with the polyester resin (B) via the bireactive compound. When the raw material monomer (a) of the styrene acrylic resin (A) contains an ethylenically unsaturated monocarboxylic acid as a bireactive compound, the styrene acrylic resin (A) is compounded via an ester bond formed by a condensation reaction between a carboxy group introduced into the polymer skeleton by containing a structural unit derived from an ethylenically unsaturated monocarboxylic acid and a hydroxy group of the polyester resin (B).

[0049] The amount of the bireactive compound capable of reacting with both the styrene acrylic resin (A) and the polyester resin (B) is preferably 1 mass % or more, more preferably 3 mass % or more, even more preferably 5 mass % or more, and preferably 25 mass % or less, more preferably 20 mass % or less, even more preferably 15 mass % or less, relative to the total amount of the raw material monomer (a) of the styrene acrylic resin (A) constituting the styrene acrylic resin unit, when the total amount of the raw material monomer (a) of the styrene acrylic resin (A) constituting the styrene acrylic resin unit is taken as 100 mass %.

[0050] In the amorphous composite resin, the mass ratio of the polyester resin (B) constituting the polyester resin unit to the styrene acrylic resin (A) constituting the styrene acrylic resin unit [polyester resin (B) / styrene acrylic resin (A)], or the mass ratio of the total amount of raw material monomers (b) constituting the polyester resin unit to the total amount of raw material monomers (a) constituting the styrene acrylic resin unit [total amount of raw material monomers (b) / total amount of raw material monomers (a)], is preferably 70 / 30 or more, more preferably 80 / 20 or more, even more preferably 90 / 10 or more, and is preferably 98 / 2 or less, more preferably 97 / 3 or less, even more preferably 96 / 4 or less, from the viewpoint of improving the dispersibility of the styrene acrylic resin unit and further improving the transferability of the toner under high temperature and high humidity conditions.

[0051] When step II is carried out by a polymer reaction, the method is not particularly limited as long as it is a method capable of forming a covalent bond, but a method in which the styrene-acrylic resin (A) and the polyester resin (B) are heated, melted, and mixed is preferred. The temperature during the polymer reaction in step II is preferably 100°C or higher, more preferably 130°C or higher, even more preferably 150°C or higher, and preferably 250°C or lower, more preferably 230°C or lower, even more preferably 220°C or lower. From the viewpoint of reactivity, the polymer reaction in step II may be carried out at normal pressure, or under increased or reduced pressure, and is preferably carried out under reduced pressure. The time for the polymer reaction may be appropriately changed depending on the reaction temperature, etc., but is preferably 1 hour or more and preferably 24 hours or less, more preferably 12 hours or less, and further preferably 6 hours or less.

[0052] (Physical properties of amorphous composite resin) From the viewpoint of further improving the transferability of the toner under high temperature and high humidity conditions, the softening point of the amorphous composite resin is preferably 85°C or higher, more preferably 90°C or higher, even more preferably 95°C or higher, and is preferably 160°C or lower, more preferably 140°C or lower, even more preferably 120°C or lower. From the viewpoint of further improving the transferability of the toner under high temperature and high humidity conditions, the glass transition temperature of the amorphous composite resin is preferably 40° C. or higher, more preferably 45° C. or higher, even more preferably 50° C. or higher, and is preferably 90° C. or lower, more preferably 80° C. or lower, even more preferably 70° C. or lower. Among these, from the viewpoint of further improving the transferability of the toner under high temperature and high humidity conditions, it is more preferable that the amorphous composite resin has a softening point of 95° C. or higher and a glass transition temperature of 50° C. or higher. From the viewpoint of improving the transferability of the toner under high temperature and high humidity conditions, the acid value of the amorphous composite resin is 5 mgKOH / g or more, preferably 10 mgKOH / g or more, more preferably 15 mgKOH / g or more, and is preferably 40 mgKOH / g or less, more preferably 35 mgKOH / g or less, and even more preferably 30 mgKOH / g or less. The softening point, glass transition temperature, and acid value of the amorphous composite resin can be measured by the method described in the Examples. When two or more kinds of amorphous composite resins are used in combination, it is preferable that the softening point, glass transition temperature, and acid value of the mixture thereof are each within the above-mentioned ranges.

[0053] <Crystalline resin> The crystalline resin is a crystalline polyester resin (C) (hereinafter, also referred to as "resin (C)").

[0054] [Crystalline polyester resin (C)] The resin (C) is, for example, a polycondensate of an alcohol component and a carboxylic acid component. The alcohol component preferably comprises 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 α,ω-aliphatic diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, and 1,14-tetradecanediol. Among these, ethylene glycol and 1,10-decanediol are preferred.

[0055] The amount of α,ω-aliphatic diol in the alcohol component is preferably 80 mol% or more, more preferably 85 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, and is 100 mol% or less, even more preferably 100 mol%.

[0056] 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-propylene glycol and neopentyl glycol; aromatic diols such as alkylene oxide adducts of bisphenol A; and trihydric or higher alcohols such as glycerin, pentaerythritol, and trimethylolpropane. These alcohol components may be used alone or in combination.

[0057] The carboxylic acid component preferably comprises an aliphatic dicarboxylic acid. The aliphatic dicarboxylic acid preferably has 4 or more carbon atoms, more preferably 6 or more carbon atoms, and preferably has 18 or less carbon atoms, more preferably 16 or less carbon atoms. Examples of the aliphatic dicarboxylic acid include fumaric acid, sebacic acid, dodecanedioic acid, and tetradecanedioic acid. Among these, sebacic acid, dodecanedioic acid, and tetradecanedioic acid are preferred, and sebacic acid is more preferred. These carboxylic acid components may be used alone or in combination.

[0058] The amount of the aliphatic dicarboxylic acid in the carboxylic acid component is preferably 75 mol % or more, more preferably 80 mol % or more, even more preferably 85 mol % or more, and is 100 mol % or less, even more preferably 100 mol %.

[0059] The carboxylic acid component may contain other carboxylic acid components different from aliphatic dicarboxylic acids. Examples of other carboxylic acid components include aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid; monocarboxylic acids such as myristic acid, palmitic acid, stearic acid, arachidic acid, and behenic acid; and polyvalent carboxylic acids having three or more valences. Among these, monocarboxylic acids are preferred, palmitic acid and stearic acid are more preferred, and stearic acid is even more preferred. These carboxylic acid components may be used alone or in combination.

[0060] 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.

[0061] (Method of producing resin (C)) The resin (C) can be obtained, for example, by polycondensation of an alcohol component and a carboxylic acid component. The polycondensation conditions can be the same as those described above for the polycondensation of the resin (B).

[0062] (Physical properties of resin (C)) The softening point of resin (C) is preferably 60° C. or higher, more preferably 70° C. or higher, even more preferably 75° C. or higher, and preferably 110° C. or lower, more preferably 100° C. or lower, even more preferably 95° C. or lower. The melting point of resin (C) is preferably 55°C or higher, more preferably 65°C or higher, even more preferably 70°C or higher, and is preferably 100°C or lower, more preferably 90°C or lower, even more preferably 85°C or lower.

[0063] The acid value of the resin (C) is preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g or more, and preferably 30 mgKOH / g or less, more preferably 25 mgKOH / g or less, and even more preferably 20 mgKOH / g or less.

[0064] The softening point, melting point and acid value of the resin (C) can be appropriately adjusted by the types and ratios of the raw material monomers, as well as production conditions such as reaction temperature, reaction time and cooling rate. These values ​​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.

[0065] The mass ratio of the crystalline resin to the amorphous composite resin (crystalline resin / amorphous composite resin) is preferably 1 / 99 or more, more preferably 5 / 95 or more, even more preferably 10 / 90 or more, and is preferably 40 / 60 or less, more preferably 35 / 65 or less, even more preferably 30 / 70 or less.

[0066] In the resin component of the toner, the total content of the amorphous composite resin and the crystalline resin is preferably 80% by mass or more, more preferably 90% by mass or more, and 100% by mass or less, preferably 95% by mass or less. The content of the amorphous composite resin in the toner particles is preferably 60% by mass or more, more preferably 65% ​​by mass or more, even more preferably 70% by mass or more, and preferably 90% by mass or less, more preferably 85% by mass or less, even more preferably 82% by mass or less. The content of the crystalline resin in the toner particles is preferably 1% by mass or more, more preferably 5% by mass or more, even more preferably 7% by mass or more, and preferably 35% by mass or less, more preferably 30% by mass or less, even more preferably 25% by mass or less.

[0067] [Method for producing resin particles] The resin particles containing the amorphous composite resin and the crystalline resin may be produced as an aqueous dispersion of the resin particles. The aqueous medium used for the aqueous dispersion is preferably one containing water as a main component.

[0068] In the present invention, the content of water in the aqueous medium is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, and 100% by mass or less. As the water, deionized water, ion-exchanged water, or distilled water is preferable. Examples of components other than water that can constitute an aqueous medium together with water include organic solvents that dissolve in water, such as alkyl alcohols having 1 to 5 carbon atoms; dialkyl ketones having 3 to 5 carbon atoms, such as acetone and methyl ethyl ketone; and cyclic ethers, such as tetrahydrofuran.

[0069] Dispersion can be performed using a known method, but it is preferable to disperse by a phase inversion emulsification method. As the phase inversion emulsification method, for example, a method of adding an aqueous medium to an organic solvent solution of an amorphous composite resin and a crystalline resin, or to a molten amorphous composite resin and a crystalline resin, and performing phase inversion emulsification can be mentioned. A method of adding an aqueous medium to an organic solvent solution of a resin and performing phase inversion emulsification is preferable. For example, by adding an aqueous medium to an organic solvent solution of an amorphous composite resin and a crystalline resin and performing phase inversion emulsification, an aqueous dispersion of resin particles containing an amorphous composite resin and a crystalline resin in the same particle can be produced. In addition, by similarly performing phase inversion emulsification of each of the amorphous composite resin and the crystalline resin, an aqueous dispersion of resin particles containing an amorphous composite resin and a crystalline resin and a crystalline resin are prepared, and these may be combined to form an aqueous dispersion of resin particles containing an amorphous composite resin and a crystalline resin. The organic solvent used for phase inversion emulsification is not particularly limited as long as it dissolves the amorphous composite resin and the crystalline resin and is water-soluble, and examples thereof include methyl ethyl ketone. A neutralizing agent may be added to the organic solvent solution. 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. Among these, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide are preferred. The degree of neutralization of the amorphous composite resin and the crystalline 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 amorphous composite resin and the crystalline 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 constituting resin particle (mgKOH / g)×weight of resin constituting resin particle (g)} / (56×1000)]]×100

[0070] When the aqueous medium is gradually added to the organic solvent solution or molten resin while stirring it to effect phase inversion emulsification, the temperature of the organic solvent solution or molten resin is, from the viewpoint of improving the dispersion stability of the resin particles containing the amorphous composite resin and the crystalline resin, preferably not less than the glass transition temperature of the amorphous composite resin, more preferably not less than 60°C, even more preferably not less than 65°C, even more preferably not less than 70°C, and is preferably not more than 100°C, more preferably not more than 90°C, even more preferably not more than 80°C.

[0071] After the phase inversion emulsification, the organic solvent may be removed from the obtained dispersion by distillation or the like, if necessary. The resin particles may also be isolated by filtration or the like. In the aggregating step and the fusion step of the present invention, it is preferable to use an aqueous dispersion of resin particles obtained by removing the organic solvent from the dispersion obtained after the phase inversion emulsification. In this case, the remaining amount of the organic solvent in the dispersion is preferably 1% by mass or less, more preferably 0.5% by mass or less, and even more preferably substantially 0% by mass.

[0072] Volume median diameter D of resin particles in dispersion 50 From the viewpoint of improving the transferability of the toner under high temperature and high humidity conditions, the particle size is preferably 0.05 μm or more, more preferably 0.08 μm or more, and is preferably 1 μm or less, more preferably 0.5 μm or less, and even more preferably 0.3 μm or less. The CV value of the resin particles in the dispersion is preferably 40% or less, more preferably 35% or less, from the viewpoint of improving the transferability of the toner under high temperature and high humidity conditions, and is preferably 10% or more, more preferably 20% or more, from the viewpoint of productivity.

[0073] From the viewpoint of improving the transferability of the toner under high temperature and high humidity conditions, the solids concentration of the aqueous dispersion of the resin particles 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. The solid content is the total amount of non-volatile components.

[0074] [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, disazo yellow, etc. The toner may be either a black toner or a color toner other than black.

[0075] The content of the colorant in the toner particles is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 5% by mass or more, and preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less.

[0076] (Colorant particle dispersion) The colorant particles are preferably mixed with resin particles as a dispersion of colorant particles, and aggregated to be contained in aggregated particles 1, and are preferably obtained by dispersing the colorant and an aqueous medium using a dispersing machine such as a homogenizer or an ultrasonic dispersing machine. From the viewpoint of improving the dispersion stability of the colorant, the dispersion is preferably carried out in the presence of an addition polymer (hereinafter, the addition polymer used to disperse the colorant is also referred to as "addition polymer E") or a surfactant. Examples of the surfactant include a nonionic surfactant, an anionic surfactant, and a cationic surfactant. The addition polymer E preferably has a constituent 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 and the addition polymer E, reference is made to the addition polymer E described in JP 2021-026129 A.

[0077] [Release Agent] Examples of the release agent include hydrocarbon waxes such as polypropylene wax, polyethylene wax, polypropylene-polyethylene copolymer wax, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax, or oxides thereof; ester waxes such as carnauba wax, montan wax, or deacidified waxes thereof, and fatty acid ester wax; fatty acid amides, fatty acids, higher alcohols, and fatty acid metal salts. These may be used alone or in combination of two or more. Among these, the hydrocarbon waxes and ester waxes are preferred, and the hydrocarbon waxes are more preferred.

[0078] 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 130° C. or lower, and further preferably 100° C. or lower.

[0079] The content of the release agent in the toner particles is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 5% by mass or more, and preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 12% by mass or less.

[0080] (Release agent particle dispersion) The release agent is preferably mixed as a release agent particle dispersion with a resin particle dispersion and a colorant particle dispersion, and then aggregated. The release agent particle dispersion can be obtained by using a surfactant, but is preferably obtained 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 surface of the release agent particles. 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. For information about the release agent particle dispersion and composite resin D, see JP 2021-026129 A.

[0081] In the step of aggregating the resin particles, the aggregation of the resin particles in the aqueous medium may be carried out in the presence of other additives in addition to the colorant and / or the release agent. As the aqueous medium, the aqueous medium shown in the method for producing resin particles can be used, and the preferred ranges are also the same. Examples of other additives include charge control agents, magnetic powders, flow improvers, conductivity adjusters, reinforcing fillers such as fibrous substances, antioxidants, antiaging agents, and cleaning improvers.

[0082] [Surfactant] In the step of aggregating the resin particles, when the dispersions of the respective particles are mixed to prepare a mixed dispersion, the process may be carried out in the presence of a surfactant from the viewpoint of improving the dispersion stability of the resin particles, the release agent particles, the colorant particles, etc. Examples of the surfactant include anionic surfactants such as alkylbenzene sulfonates and alkyl ether sulfates; and nonionic surfactants such as polyoxyethylene alkyl ethers and polyoxyethylene alkenyl ethers. When a surfactant is used, the total amount used is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, and even more preferably 0.3 parts by mass or more, relative to 100 parts by mass of the total amount of resin particles, and is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and even more preferably 1 part by mass or less.

[0083] [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 1, 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.

[0084] For example, 5 parts by mass or more and 50 parts by mass or less of the aggregating agent is added to a mixed dispersion liquid containing resin particles, release agent particles, and colorant particles at 0° C. or more and 40° C. or less, 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 1. Furthermore, from the viewpoint of promoting aggregation, it is preferable to increase the temperature of the dispersion liquid after adding the aggregating agent.

[0085] Examples of a method for stopping the aggregation include a method of cooling the dispersion, a method of adding an aggregation terminator, a method of diluting the dispersion, etc. From the viewpoint of reliably preventing unnecessary aggregation, a method of stopping the aggregation by adding an aggregation terminator is preferred.

[0086] [Aggregation Stopper] 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, etc. 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, more preferably 3 parts by mass or more, per 100 parts by mass of the resin in the resin particles, from the viewpoint of reliably preventing unnecessary aggregation, and is preferably 15 parts by mass or less, more preferably 12 parts by mass or less, and even more preferably 10 parts by mass or less, from the viewpoint of reducing residue in the toner.

[0087] Volume median particle size D of aggregate 1 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.

[0088] In the present invention, after the step of aggregating the resin particles and before the step of fusing, a step of aggregating the shell resin particles may be included in which shell resin particles containing an amorphous resin (preferably an amorphous polyester resin) are attached to the obtained aggregated particles 1 to obtain aggregated particles 2. By including the step of aggregating the shell resin particles, toner particles having a core-shell structure can be obtained. Here, the amorphous resin used in the shell resin particles is exemplified by the above-mentioned polyester resin (B). The shell resin particles can be obtained by the same method as the resin particles containing the above-mentioned amorphous resin and / or crystalline resin. Furthermore, when the toner manufacturing method includes a step of aggregating shell resin particles, it is preferable to stop the aggregation in the step when the aggregated particles 2 have grown to an appropriate particle size for toner particles, and a method of stopping the aggregation by adding the above-mentioned aggregation terminator is preferable.

[0089] [Fusing process] In the fusion step, for example, the aggregated particles are fused in an aqueous medium. By fusion, the particles contained in the aggregated particles are fused together to obtain fused particles. In the fusion step, from the viewpoint of improving the fusion properties of the aggregated particles and from the viewpoint of improving the transferability of the toner under high temperature and high humidity conditions, 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 among the resins contained 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 5° C. higher than the glass transition temperature of the resin having the highest glass transition temperature among the resins contained in the aggregated particles, more preferably at least 10° C. higher, and even more preferably at least 15° C. higher, and is preferably not more than 40° C. higher, more preferably not more than 30° C. higher, and even more preferably not more than 25° C. higher than the glass transition temperature of the resin. In this case, the time for which the toner is maintained at a temperature equal to or higher than the glass transition temperature of the resin is, from the viewpoint of improving the transferability of the toner under high temperature and high humidity conditions, 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 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.

[0090] 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.

[0091] The circularity of the fused particles obtained by fusion is preferably 0.955 or more, more preferably 0.960 or more, and is preferably 0.990 or less, more preferably 0.985 or less, and further 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.

[0092] [Post-processing process] A post-treatment process may be performed after the fusion process, and the fused particles are isolated to obtain toner particles. Since the fused particles obtained in the fusion process are present in an aqueous medium, it is preferable to first perform solid-liquid separation. For solid-liquid separation, a suction filtration method or the like is preferably used. It is preferable to wash the solid-liquid separation product. In this case, it is preferable to remove the added surfactant, so that washing with an aqueous medium at a temperature below the cloud point of the surfactant is preferable. 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.

[0093] [Toner Particles] Volume median particle size of toner particles D 50 is preferably 2 μm or more, more preferably 3 μm or more, even more preferably 4 μm or more, and is preferably 10 μm or less, more preferably 8 μm or less, even more preferably 7 μm or less.

[0094] The circularity of the toner particles is preferably 0.955 or more, more preferably 0.960 or more, from the viewpoint of obtaining high quality images, and is preferably 0.990 or less, more preferably 0.985 or less, and even more preferably 0.980 or less, from the viewpoint of cleaning properties.

[0095] 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 40% or less, more preferably 35% or less, and even more preferably 30% or less. Volume median particle size of toner particles D 50 The CV value can be measured by the method described in the Examples.

[0096] [Toner for developing electrostatic images] The toner for developing electrostatic images of the present invention comprises 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.

[0097] <External additives> In order to improve the fluidity, the toner of the present invention may contain toner particles and an external additive by treating the surface of the toner particles with a property improving agent such as an external additive. Examples of the external additive include inorganic material particles such as silica, alumina, titania, zirconia, tin oxide, and zinc oxide, and organic particles such as resin particles such as melamine resin particles and polytetrafluoroethylene resin particles. These may be used alone or in combination. Among these external additives, silica is preferred, and hydrophobic silica treated with a hydrophobic treatment agent is more preferred.

[0098] Examples of hydrophobic treatment agents include hexamethyldisilazane (HMDS), dimethyldichlorosilane (DMDS), silicone oil, octyltriethoxysilane (OTES), methyltriethoxysilane, and dimethylpolysiloxane. Among these, hexamethyldisilazane is preferred.

[0099] When the toner particles are surface-treated using an external additive, the content of the external additive is, from the viewpoint of the chargeability and fluidity of the toner, preferably 0.1 part by mass or more, more preferably 0.5 part by mass or more, even more preferably 1 part by mass or more, and is preferably 10 parts by mass or less, more preferably 6 parts by mass or less, and even more preferably 4 parts by mass or less, relative to 100 parts by mass of the toner particles. 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

[0100] [Measurement method] The physical properties of the polyester resin, resin particles, toner, etc. were measured and evaluated by the following methods.

[0101] [Weight average molecular weight of addition polymer] The measurement was performed by gel permeation chromatography (GPC apparatus "HLC-8320GPC" (manufactured by Tosoh Corporation), columns "TSKgel SuperAWM-H", "TSKgel SuperAW3000", "TSKgel guardcolum Super AW-H" (manufactured by Tosoh Corporation), flow rate: 0.5mL / min) using a solution of phosphoric acid and lithium bromide dissolved in N,N-dimethylformamide to a concentration of 60mmol / L and 50mmol / L, respectively, as an eluent, and using a monodisperse polystyrene kit with known molecular weights (PStQuick B (F-550, F-80, F-10, F-1, A-1000), PStQuick C (F-288, F-40, F-4, A-5000, A-500), manufactured by Tosoh Corporation) as a standard substance.

[0102] [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.

[0103] [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)).

[0104] [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.

[0105] [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

[0106] [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%)

[0107] [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.

[0108] [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

[0109] [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 the volume average particle size DV were calculated. 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] [Production of resin] Production Examples A1 to A4 and Comparative Production Examples A1 and A2 (Production of Resins A-1 to A-4, A-11, and A-12) The raw material monomer (a) of the addition polymerization resin shown in Table 1 was placed in an autoclave equipped with a stainless steel stirring rod, and the raw material monomer (a) was bulk polymerized under pressurized and heated conditions (300°C) for 2 hours. The pressure and temperature were returned to normal, and the precipitated styrene-acrylic resin was collected to obtain styrene-acrylic resins A-1 to A-4, A-11, and A-12. Various physical properties are shown in Table 1.

[0111] [Table 1]

[0112] Production Examples B1 to B6 and Comparative Production Examples B1 to B2 (Production of Amorphous Composite Resins 1 to 6, 11, and 12) The raw material monomer (b) of the polyester resin (B) constituting the polyester resin unit shown in Table 2, the esterification catalyst, and the esterification promoter were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a dehydration tube equipped with a fractionating tube through which hot water of 98 ° C. was passed, and a nitrogen inlet tube were placed in the flask. After holding at 180 ° C. for 1 hour in a mantle heater in a nitrogen atmosphere, the temperature was raised from 180 ° C. to 230 ° C. at 10 ° C. / h, and then polycondensation reaction was carried out at 230 ° C. for 5 hours, and further reaction was carried out at 230 ° C. and 8.0 kPa for 1 hour. After cooling to 210 ° C., styrene acrylic resin (A) was added, held at 210 ° C. for 4 hours, and then reacted under reduced pressure of 8.0 kPa. It was confirmed that the softening point of the resin reached the predetermined softening point shown in Table 2, and the reaction was stopped to obtain composite resins 1 to 6, 11, and 12.

[0113] Comparative Production Example B3 (Production of Amorphous Resin 13) The raw material monomer (b) of polyester resin (B) constituting the polyester resin unit shown in Table 2, an esterification catalyst, and an esterification promoter were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a dehydration tube equipped with a fractionating tube through which 98°C hot water had passed, and a nitrogen inlet tube, and the mixture was held at 180°C for 1 hour in a mantle heater in a nitrogen atmosphere, and then heated from 180°C to 220°C at a rate of 10°C / h. Thereafter, a polycondensation reaction was carried out at 220°C for 5 hours, and the reaction was further carried out at 220°C and 8.0 kPa until the softening point shown in Table 2 was reached, thereby obtaining amorphous resin 13.

[0114] [Table 2]

[0115] Production Examples C1 to C2 (Production of Crystalline Polyester Resins C-1 and C-2) The raw material monomers for the polyester resins shown in Table 3 were added to a 10-liter four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple, and the inside of the flask was replaced with nitrogen. The contents were heated to 135° C. with stirring, and the temperature was maintained at 135° C. for 3 hours, after which the temperature was increased from 135° C. to 200° C. over 10 hours. An esterification catalyst was then added, and the flask was further maintained at 200° C. for 1 hour. The pressure in the flask was then reduced, and the flask was maintained under a reduced pressure of 8 kPa for 1 hour to obtain crystalline polyester resins C-1 and C-2.

[0116] [Table 3]

[0117] [Production of Resin Particle Dispersion] Production Example X1 (Production of Resin Particle Dispersion X-1) In a 3 L vessel equipped with a stirrer, a reflux condenser, a dropping funnel, a thermometer, and a nitrogen inlet tube, 160 g of amorphous composite resin 1, 40 g of crystalline polyester resin C-1, and 200 g of methyl ethyl ketone were placed 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 the resin was 60 mol%, and the mixture was stirred for 30 minutes. Next, while maintaining the temperature at 73°C, 700 g of deionized water was added over 50 minutes while stirring at 280 r / min to cause phase inversion emulsification. The obtained solution was maintained at 73°C, and 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. Volume median particle diameter D 50 and CV values ​​are shown in Table 4.

[0118] Production Examples X2 to X7 and Comparative Production Examples X1 to X3 (Production of Resin Particle Dispersions X-2 to X-7 and X-11 to X-13) Resin particle dispersions X-2 to X-7 and X-11 to X-13 were obtained in the same manner as in Production Example X1, except that the types of the amorphous composite resin or amorphous resin and the crystalline polyester resin (C) were changed as shown in Table 4. The volume median particle diameter D 50 and CV values ​​are shown in Table 4.

[0119] Comparative Production Example X4 (Production of Resin Particle Dispersion X-14) A resin particle dispersion X-14 was obtained in the same manner as in Production Example X1, except that the resin and its amount were changed as shown in Table 4. The volume median particle diameter D of the resin particles in the obtained resin particle dispersion 50 and CV values ​​are shown in Table 4.

[0120] [Table 4]

[0121] Manufacturing Example D1 (Manufacturing of Composite 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 were added, and the reaction system was heated to 235°C while stirring under a nitrogen atmosphere, and then held at 235°C for 5 hours, after which the pressure in the flask was reduced and held at 8kPa for 1 hour. After that, the pressure was returned to atmospheric pressure, and then cooled to 160°C, and while the temperature was held 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 to the reaction system 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 reached, to obtain composite resin D-1. The physical properties are shown in Table 5.

[0122] [Table 5]

[0123] Production Example S1 (Production of Resin Particle Dispersion S-1) In a 3 L vessel equipped with a stirrer, a reflux condenser, a dropping funnel, a thermometer, and a nitrogen inlet tube, 200 g of Resin D-1 and 200 g of methyl ethyl ketone were placed and 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 D-1 was 60 mol %, and the mixture was stirred for 30 minutes. Next, while maintaining the temperature at 73°C, 700 g of deionized water was added over 50 minutes while stirring at 280 r / min, and phase inversion emulsification was performed. While maintaining the temperature at 73°C, methyl ethyl ketone was distilled off under reduced pressure to obtain an aqueous dispersion. Thereafter, while stirring at 280 r / min, the aqueous dispersion was cooled to 30°C, and deionized water was added so that the solid concentration was 20 mass%, to obtain resin particle dispersion S-1. Volume median particle diameter D of resin particles in resin particle dispersion S-150 The diameter was 0.90 μm and the CV value was 23%.

[0124] 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 while 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 50 The thickness was 0.28 μm and the CV value was 20%.

[0125] 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 0.24 μm and the CV value was 20%.

[0126] [Production of Addition Polymer E] Production Example E1 (Synthesis of Addition Polymer E-1) The types and amounts of raw material monomers shown in Table 6 were mixed to prepare a monomer mixture having a total monomer amount of 100 g. The inside of a four-neck flask equipped with a nitrogen inlet tube, a dropping funnel, a stirrer, and a thermocouple was replaced with nitrogen, and 18 g of methyl ethyl ketone, 0.03 g of 2-mercaptoethanol, and 10% by mass of the monomer mixture were added and heated to 75°C while stirring. While maintaining the temperature at 75°C, a mixture of the remaining 90% by mass of the monomer mixture, 0.27 g of 2-mercaptoethanol, 42 g of methyl ethyl ketone, and 3 g of 2,2'-azobis(2,4-dimethylvaleronitrile) "V-65" (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was dropped from the dropping funnel over 3 hours. After the dropwise addition, the temperature was maintained at 75°C for 2 hours, and then a solution in which 3 g of 2,2'-azobis(2,4-dimethylvaleronitrile) was dissolved in 5 g of methyl ethyl ketone was added, and the mixture was further maintained at 75°C for 2 hours and at 80°C for 2 hours. Thereafter, methyl ethyl ketone was distilled off under reduced pressure to obtain addition polymer E-1. The weight average molecular weight of the obtained addition polymer is shown in Table 6.

[0127] [Table 6]

[0128] [Production of colorant dispersion] Production Example Z1 (Production of Colorant Dispersion Z-1) In a 5L container equipped with a stirrer equipped with a dispersing blade, a reflux condenser, a dropping funnel, a thermometer and a nitrogen inlet tube, 75 g of the addition polymer E-1 and 630 g of methyl ethyl ketone were placed and the addition polymer E-1 was dissolved at 20°C. 101 g of 5% by mass aqueous sodium hydroxide solution (an amount that makes the degree of neutralization of the addition polymer E-1 91 mol%) was added to the obtained solution, and 955 g of deionized water was further added and stirred with a dispersing blade at 20°C for 10 minutes. Next, 300 g of Pigment Yellow 155 (manufactured by Clariant Chemicals Co., Ltd., "Toner Yellow 3GP-CT", molecular weight 717) was added, and stirring was performed with a dispersing blade at 6400 r / min at 20°C for 2 hours. Thereafter, the mixture was passed through a 200 mesh filter and treated with a homogenizer "Microfluidizer M-110EH" (manufactured by Microfluidics) at a pressure of 150 MPa for 15 passes. The resulting dispersion was stirred at reduced pressure at 70° C. to remove methyl ethyl ketone and a portion of the water. After cooling, the mixture was passed through a 200 mesh filter, and deionized water was added to give a solids concentration of 20% by mass to obtain colorant dispersion Z-1. The volume median particle diameter D of the colorant particles in the resulting colorant dispersion Z-1 was 50 The thickness was 0.10 μm and the CV value was 28%.

[0129] [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, 500 g of resin particle dispersion X-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 Z-1, and 3.3 g of 15 mass % sodium dodecylbenzenesulfonate aqueous solution "Neopelex G-15" (Kao Corporation, anionic surfactant) were placed and mixed at a temperature of 25° C. Next, while stirring the mixture, a solution obtained by dissolving 43 g of ammonium sulfate in 980 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 6.2 μm, thereby obtaining a dispersion of aggregated particles 1. To the obtained dispersion liquid of aggregated particles 1, 22 g of sodium polyoxyethylene lauryl ether sulfate "EMAL E-27C" (manufactured by Kao Corporation, anionic surfactant, effective concentration 27% by mass) and 1100 g of deionized water were added. Thereafter, the temperature was raised to 75°C over one 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 1 were fused. The obtained dispersion of fused particles was cooled to 30° C., and the dispersion was filtered under suction to separate the solid content, which was then washed with deionized water at 25° C. and filtered under suction for 2 hours at 25° C. Thereafter, the solid content was vacuum dried at 33° C. for 24 hours using a vacuum low-temperature dryer "DRV622DA" (manufactured by ADVANTEC Corporation) to obtain toner particles. The physical properties of the toner particles are shown in Table 7.

[0130] 100 parts by mass of toner particles, 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 and stirred, and the mixture was passed through a 150 mesh sieve to obtain toner 1.

[0131] [Toner Evaluation] [Transferability under high temperature and high humidity conditions] All solid images were printed on a commercially available printer, the ML5400 (manufactured by Oki Data Corporation), using Excellent White paper (80 g / m 2 Print on paper at a temperature of 35°C and humidity of 80%, and when half of the A4 size has been transferred, stop the machine, and apply a transparent mending tape "SCOTCH Mending Tape 810-3-18" (manufactured by 3M Japan Ltd.) to the surface of the photoconductor after transfer, and collect the residual toner on the surface of the photoconductor. Apply a reference mending tape and the mending tape with the residual toner collected on a piece of unused excellent white paper, place it on top of 30 pieces of the same paper, and use a colorimeter "SpectroEye" (manufactured by Gretag-Macbeth) to measure the whiteness of the reference mending tape as the white standard, with the light irradiation conditions of standard light source D50 and observation field of view 2°, and measure the whiteness of the reference mending tape as the white standard, with the CIE L* a * b * Then, measure the CIE L of the mending tape from which the residual toner was collected. * a * b * Measure the color and the color difference with the reference ΔE = {(ΔL * ) 2 +(Δa * ) 2 +(Δb * ) 2} 1 / 2 The value was used as an index for evaluating the transferability. The smaller the ΔE value, the less residual toner there was and the better the transferability. The results are shown in Table 7.

[0132] [Low temperature fixability] Using a commercially available printer "Microline (registered trademark) 5400" (Oki Data Corporation) on high-quality paper "J paper A4 size" (Fuji Xerox Co., Ltd.), the amount of toner attached to the paper was 0.60 ± 0.01 mg / cm 2 The solid image was printed without fixing, leaving a margin of 5 mm from the top edge of A4 paper, and a length of 50 mm. Next, the same printer was prepared with a modified temperature-variable fixing unit, the temperature of the fixing unit was set to 90° C., and the toner was fixed on A4 sheets in portrait orientation at a speed of 1.2 seconds per sheet to obtain a printout. In the same manner, the temperature of the fixing unit was increased by 5° C. each time, and the toner was fixed to obtain a printed matter. A piece of mending tape, Scotch (registered trademark) Mending Tape 810 (manufactured by 3M Japan Ltd., width 18 mm), cut to a length of 50 mm was lightly applied from the top margin of the printed image to the solid image, and then a 500 g weight (contact area 1963 mm 2) was placed on the print and pressed against it once at a speed of 10 mm / s. The applied tape was then peeled off from the bottom end at a peeling angle of 180° and a speed of 10 mm / s to obtain a print after the tape had been peeled off. 30 sheets of high-quality paper "Excellent White Paper A4 Size" (manufactured by OKI Data Corporation) were placed under the print before and after the tape had been applied and peeled off, and the reflected image density of the fixed image portion of each print before and after the tape had been applied and peeled off was 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), and the fixing rate was calculated from each reflected image density according to the following formula. Fixation rate (%) = (reflection image density after tape peeling / reflection image density before tape application) x 100 The lowest temperature at which the fixing rate was 90% or more was defined as the minimum fixing temperature. The lower the minimum fixing temperature, the better the low-temperature fixing property. The results are shown in Table 7.

[0133] Examples 2 to 7, Comparative Examples 1 to 3, and Reference Example 1 (Toners 2 to 7, 11 to 13, and 21) Toner particles and toners 2 to 7, 11 to 13, and 21 were obtained in the same manner as in Example 1, except that the resin particle dispersion used was changed as shown in Table 7. The physical properties of the toner particles are shown in Table 7. Further, using toners 2 to 7, 11 to 13, and 21, the transferability and low-temperature fixability in a high-temperature and high-humidity environment were evaluated in the same manner as in Example 1. The results are shown in Table 7.

[0134] [Table 7]

[0135] As shown in Table 7, it is clear that the toners 1 to 7 of the examples have excellent transferability under high temperature and high humidity conditions, despite containing a crystalline resin. On the other hand, although toners 11 to 13 of Comparative Examples 1 to 3 exhibited low-temperature fixing properties equivalent to those of the toners of the Examples, when printed under high temperature and high humidity conditions, untransferred toner remained on the photoreceptor, and the transferability under high temperature and high humidity conditions was insufficient.

Claims

1. A method for producing a toner, comprising a step of aggregating and fusing resin particles containing an amorphous composite resin and a crystalline resin in an aqueous medium, the amorphous composite resin is a composite resin in which a styrene-acrylic resin unit and a polyester resin unit are bonded via a covalent bond, the styrene acrylic resin (A) constituting the styrene acrylic resin unit contains 40 mass% or more of structural units derived from a (meth)acrylic monomer, and the styrene acrylic resin (A) has an acid value of 60 mgKOH / g or more; the polyester resin (B) constituting the polyester resin unit is a polycondensate of an alcohol component containing an aliphatic diol and a carboxylic acid component, The method for producing a toner, wherein the crystalline resin is a crystalline polyester resin.

2. The method for producing a toner according to claim 1 , wherein the (meth)acrylic monomer comprises an alkyl ester of (meth)acrylic acid having 1 to 6 carbon atoms.

3. The method for producing a toner according to claim 1 or 2, wherein the aliphatic diol has from 2 to 6 carbon atoms.

4. A method for producing a toner as described in claim 1 or 2, wherein the content of the aliphatic diol in the alcohol component is 90 mol% or more.

5. Step I: a step of polymerizing raw material monomer (a) of the styrene acrylic resin (A) constituting the styrene acrylic resin unit in an independent polymerization system separate from a polymerization system of raw material monomer (b) constituting the polyester resin (B) in the absence of polyester resin (B) constituting the polyester resin unit, to obtain the styrene acrylic resin (A); and Step II: A step of bonding the styrene-acrylic resin (A) obtained in Step I with the polyester resin (B) via a covalent bond to obtain the composite resin; The method for producing the toner according to claim 1 or 2, comprising:

6. The method for producing a toner according to claim 1 or 2, wherein the styrene-acrylic resin (A) is obtained by bulk polymerization.

7. 3. The method for producing a toner according to claim 1, wherein the styrene-acrylic resin (A) has a glass transition temperature of 50°C or higher and a softening point of 100°C or higher.