Method for manufacturing toner

Abstract

To provide a method for manufacturing toner excellent in solid followability and hot-offset resistance.SOLUTION: A method for manufacturing toner comprises aggregating and fusing particles including an amorphous composite resin (CH) and colorant particles in the presence of polyvalent metal salt in an aqueous medium. The amorphous composite resin (CH) includes a polyester segment (CH-1) and a vinyl resin segment (CH-2) being the addition polymer of a monomer component including a styrene based compound; the polyester segment (CH-1) and the vinyl resin segment (CH-2) are compounded by polymeric reaction; the acid number of a vinyl resin constituting the vinyl resin segment (CH-2) is 40 mgKOH / g or more; and the hydroxyl value of the amorphous composite resin (CH) is 20 mgKOH / g or less.SELECTED DRAWING: None

Description

[Technical field]

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

[0002] 2. Description of the Related Art In recent years, in the field of electrophotography, with the development of electrophotographic systems, there has been a demand for the development of toners for developing electrostatic images that are compatible with higher image quality and faster printing.

[0003] Patent Document 1 discloses a toner binder resin containing 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 having an acid value of 40 mgKOH / g or more, for the purpose of obtaining a toner binder resin and a toner for developing electrostatic images that are excellent in low-temperature fixing property, hot offset resistance, heat-resistant storage property, and charge stability, and discloses a toner binder resin and a toner for developing electrostatic images that contain the toner binder resin. Furthermore, Patent Document 2 discloses an electrophotographic toner obtained by a method including a step of granulating a raw material containing a binder resin in an aqueous medium, for the purpose of obtaining an electrophotographic toner excellent in hydrolysis resistance, low-temperature fixing property, hot offset resistance, storage stability and durability, 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 condensing 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. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2021-107920 A [Patent Document 2] JP 2010-107675 A Summary of the Invention [Problem to be solved by the invention]

[0005] In order to improve toner performance, a toner has been produced by aggregating and fusing a composite resin of a polyester segment and a vinyl resin segment, which is an addition polymer of a styrene compound and a vinyl monomer having a carboxy group, using an emulsion aggregation method. However, the toner has still not achieved sufficient solid image tracking ability or hot offset resistance. The present invention relates to a method for producing a toner having excellent solid image conformability and hot offset resistance. [Means for solving the problem]

[0006] The present inventors have found that the above-mentioned problems can be solved by emulsifying an amorphous composite resin having a specific structure and a specific hydroxyl value, and aggregating particles containing the amorphous composite resin and colorant particles in the presence of a polyvalent metal salt to form toner particles. The present invention relates to the following [1]. [1] A method for producing a toner, comprising agglomerating and fusing particles containing an amorphous composite resin (CH) and colorant particles in an aqueous medium in the presence of a polyvalent metal salt to form toner particles, wherein the amorphous composite resin (CH) contains a polyester segment (CH-1) and a vinyl resin segment (CH-2) which is an addition polymer of a monomer component containing a styrene compound, the polyester segment (CH-1) and the vinyl resin segment (CH-2) are composited by a polymer reaction, the acid value of the vinyl resin constituting the vinyl resin segment (CH-2) is 40 mgKOH / g or more, and the hydroxyl value of the amorphous composite resin (CH) is 20 mgKOH / g or less. Effect of the Invention

[0007] According to the present invention, a method for producing a toner having excellent solid image conformability and hot offset resistance can be provided. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] [Toner manufacturing method] The toner manufacturing method of the present invention is a method for manufacturing a toner, which comprises aggregating and fusing particles containing an amorphous composite resin (CH) and colorant particles in an aqueous medium in the presence of a polyvalent metal salt to form toner particles, wherein the amorphous composite resin (CH) contains a polyester segment (CH-1) and a vinyl resin segment (CH-2) which is an addition polymer of a monomer component containing a styrene-based compound, the polyester segment (CH-1) and the vinyl resin segment (CH-2) are composited by a polymer reaction, the acid value of the vinyl resin constituting the vinyl resin segment (CH-2) is 40 mgKOH / g or more, and the hydroxyl value of the amorphous composite resin (CH) is 20 mgKOH / g or less. According to the present invention, a toner having excellent solid image conformability and hot offset resistance can be obtained.

[0009] The reason why the present invention has an effect is not clear, but is thought to be as follows. Conventionally, toner particles are produced by aggregating and fusing a composite resin of a polyester segment and a vinyl resin segment, which is an addition polymer of a monomer component containing a styrene compound, by an emulsion aggregation method, but when a polyvalent metal salt is used as an aggregating agent, the solid-color conformability tends to be insufficient. This is thought to be due to the fact that the dispersion stability of each component particle, such as composite resin particles and colorant particles, which are aggregated during toner production, is not uniform, and the dispersion stability of the composite resin particles in particular tends to be low, and the use of a polyvalent metal salt increases the aggregation speed and increases the variation in the ease of aggregation of each component particle, resulting in a low circularity of the obtained toner particles, and as a result, the flowability of the toner is low. In addition, in the conventional method for producing a composite resin, addition polymerization of a monomer component containing a styrene-based compound is carried out in the system at the same time as the polyester is polycondensed. Therefore, the addition polymerization of the monomer component containing a styrene-based compound cannot be sufficiently controlled, and acid groups tend to be present non-uniformly in the structure of the vinyl resin segment. In addition, low molecular weight components that do not have acid groups (i.e., have hydroxyl groups at both ends) tend to be present in the resulting polyester segment. On the other hand, in the toner manufacturing method of the present invention, when manufacturing the amorphous composite resin (CH), a vinyl resin segment (CH-2), which is an addition polymer of a monomer component containing a styrene-based compound, is formed by polymerization separately from the polycondensation of the polyester segment (CH-1), and the separately formed polyester segment (CH-1) and the vinyl resin segment (CH-2) are bonded by a polymer reaction to manufacture the amorphous composite resin. This makes it possible to make the acid group uniformly present in the structure of the vinyl resin segment (CH-2). Furthermore, since the uniformly present acid group efficiently reacts with the low molecular weight component that does not have an acid group and is present in the polyester segment (CH-1), the presence ratio can be reduced, and the obtained amorphous composite resin has a low hydroxyl value and the dispersion of the amorphous composite resin particles can be stabilized. As a result, even if a polyvalent metal salt is used as an aggregating agent during toner manufacturing, the aggregation of the toner particles can be controlled and the circularity of the toner particles can be improved, so that the fluidity of the toner can be improved and the solid tracking ability can be improved. In addition, the acid groups uniformly present in the structure of the vinyl resin segment (CH-2) form a pseudo-crosslinked structure with the polyvalent metal salt, improving the elasticity of the toner particles at high temperatures. For this reason, it is believed that the toner obtained by the present invention has improved hot offset resistance.

[0010] The definitions of various terms used in this specification are given below. In the present specification, the carboxylic acids described as the carboxylic acid components of the polyester resins include not only the carboxylic acids 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). With respect to hydrocarbon groups, the references "(iso or tertiary)" and "(iso)" in parentheses refer to both the cases with and without the prefixes present; the absence of the prefixes indicates normal. "(Meth)acrylic acid" means at least one selected from acrylic acid and methacrylic acid. "(Meth)acrylate" means at least one selected from acrylate and methacrylate. 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.

[0011] A method for producing a toner according to one embodiment of the present invention includes, for example, A step of aggregating particles containing an amorphous composite resin (CH) and colorant particles in an aqueous medium in the presence of a polyvalent metal salt to obtain aggregated particles (hereinafter also referred to as "step 1"); and A step of fusing the aggregated particles in an aqueous medium (hereinafter also referred to as "step 2"). Includes.

[0012] <Process 1> In step 1, particles containing an amorphous composite resin (CH) and colorant particles are aggregated in an aqueous medium in the presence of a polyvalent metal salt to obtain aggregated particles. In step 1, in addition to the resin particles and colorant particles, other additives such as a release agent may also be aggregated.

[0013] (Amorphous composite resin (CH)) The amorphous composite resin contains a polyester segment (CH-1) and a vinyl resin segment (CH-2), which is an addition polymer of a monomer component containing a styrene-based compound (hereinafter also referred to as a "vinyl resin"), and the polyester segment (CH-1) and the vinyl resin segment (CH-2) are composited by a polymer reaction. The acid value of the vinyl resin constituting the vinyl resin segment (CH-2) is 40 mgKOH / g or more from the viewpoint of improving the hot offset resistance and solid print conformability of the resulting toner. Since the composite method in the present invention is a method based on a polymerization reaction, it is preferable that the polymerization reaction of each of the polyester resin and the vinyl resin is carried out in an independent reaction system. It is preferable that the polymerization system of the polyester resin is a polycondensation type, and the polymerization system of the vinyl resin is an addition polymerization type. The independent reaction system means that the polycondensation of the polyester resin and the addition polymerization of the vinyl resin are carried out in separate reaction fields. That is, it means that the polycondensation of the polyester resin is carried out in the absence of the vinyl resin and the raw material monomer (2) of the vinyl resin, and the addition polymerization of the vinyl resin is carried out in the absence of the polyester resin and the raw material monomer (1) of the polyester resin. As long as each of the above polymerization reactions is an independent reaction system, the progress and completion of the two polymerization reactions do not need to occur simultaneously in time, and the reactions may be progressed and completed by appropriately selecting the reaction temperature and time according to the respective reaction mechanisms. In the above-mentioned polymer reaction, the method of mixing the polyester resin and the vinyl resin is not particularly limited. For example, the polyester resin may be isolated and then mixed with the vinyl resin, or the polyester resin may be added to the vinyl resin without isolating it, and then mixed.

[0014] (Manufacturing method of amorphous composite resin (CH)) In the present invention, the amorphous composite resin (CH) is obtained by compounding a polyester segment (CH-1) and a vinyl resin segment (CH-2) through a polymer reaction. The method for producing a binder resin of the present invention is, from the viewpoint of further improving low-temperature fixing property, hot offset resistance, heat-resistant storage stability, and charging stability, Step I: A step of obtaining a vinyl resin segment (CH-2) by polymerizing a raw material monomer (2) in a polymerization system independent of a polymerization system of a raw material monomer (1) constituting the polyester segment (CH-1) in the absence of a polyester segment (CH-1); and Step II: A step of compounding the vinyl resin segment (CH-2) obtained in Step I with the polyester segment (CH-1) by a polymer reaction to obtain the amorphous composite resin (CH); It is preferred that the compound contains

[0015] Moreover, from the viewpoint of improving the hot offset resistance and solid print conformability of the toner obtained, the method for producing the amorphous composite resin (CH) of the present invention preferably further includes the following step I′. Step I': A step of obtaining a polyester resin by polymerizing the raw material monomer (1) constituting the polyester segment (CH-1) in an independent polymerization system different from the polymerization system of the raw material monomer (2) constituting the vinyl resin constituting the vinyl resin segment (CH-2) in the absence of the vinyl resin constituting the vinyl resin segment (CH-2). In the present invention, when the step I' is included, the step II is preferably a step of obtaining the amorphous composite resin (CH) by bonding the vinyl resin obtained in the step I and the polyester resin 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 vinyl resin and the polyester resin from the viewpoint of sufficient composite and improving the hot offset resistance and solid followability of the obtained toner. As a result, the vinyl resin and the polyester resin are bonded through an ester bond, which is a covalent bond, and are composited. The condensation reaction may be a condensation reaction of a carboxy group of the vinyl resin and a hydroxy group of the polyester resin, or a condensation reaction of a hydroxy group of the vinyl resin and a carboxy group of the polyester resin.

[0016] In step II, from the viewpoint of achieving sufficient compounding and improving the hot offset resistance and solid print conformability of the toner obtained, it is preferable that the compounding of the polyester segment (CH-1) and the vinyl resin segment (CH-2) is carried out by forming a covalent bond via a vinyl monomer having a carboxy group. That is, step II is preferably a step of forming a covalent bond by a polymer reaction between the vinyl resin segment (CH-2) and the polyester segment (CH-1) via a constituent unit derived from the vinyl monomer having a carboxy group contained in the vinyl resin segment (CH-2) to obtain the amorphous composite resin.

[0017] 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 of heating the polyester segment (CH-1) and the vinyl resin segment (CH-2) to melt and mix them and cause a condensation reaction 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. The polymer reaction in step II may be carried out under increased or reduced pressure from the viewpoint of reactivity, but is preferably carried out at normal pressure from the viewpoint of ease of reaction. 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.

[0018] [Vinyl resin segment (CH-2)] The vinyl resin segment (CH-2) of the amorphous composite resin is an addition polymer of raw material monomer (2) containing a styrene compound. By using the vinyl resin as an addition polymer of raw material monomer (2) containing a styrene compound, the hot offset resistance and solid print conformability of the resulting toner can be improved. Furthermore, the vinyl resin segment (CH-2) of the amorphous composite resin preferably contains a vinyl monomer having a carboxy group as the raw material monomer (2). That is, the vinyl resin segment (CH-2) of the amorphous composite resin is preferably an addition polymer of raw material monomer (2) containing a styrene compound and a vinyl monomer having a carboxy group. By using the vinyl resin as an addition polymer of raw material monomer (2) containing a styrene compound and a vinyl monomer having a carboxy group, the hot offset resistance and solid followability of the obtained toner can be improved. In the present invention, the vinyl resin may further contain a (meth)acrylic acid ester as the raw material monomer (2).

[0019] Examples of the styrene-based compound 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 are preferably styrene and α-methylstyrene. That is, in the vinyl resin segment (CH-2), the styrene-based compound preferably contains one or more selected from styrene and α-methylstyrene, and more preferably contains styrene and α-methylstyrene.

[0020] The vinyl monomer having a carboxy group is preferably a compound capable of reacting with both the raw material monomer (1) of the polyester resin and a styrene compound, and more preferably a compound capable of forming a complex by forming an ester bond by a condensation reaction between the polyester resin and a vinyl resin. Examples of vinyl monomers having a carboxy group include ethylenically unsaturated monocarboxylic acid compounds and ethylenically unsaturated dicarboxylic acid compounds. Specific examples of the ethylenically unsaturated monocarboxylic acid compound include acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, and lower alkyl esters and anhydrides thereof. Among these, preferred is one or more selected from acrylic acid and methacrylic acid, more preferred is acrylic acid. Specific examples of ethylenically unsaturated dicarboxylic acid compounds include maleic acid, fumaric acid, itaconic acid, mesaconic acid, citraconic acid, and lower alkyl esters and anhydrides thereof. That is, in the vinyl resin segment (CH-2), the monomer component preferably contains one or more selected from acrylic acid and methacrylic acid, and more preferably contains acrylic acid.

[0021] Examples of (meth)acrylic acid esters include 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 methyl α-chloroacrylate. Incidentally, the term "(meth)acrylic acid ester" refers to both acrylic acid ester and methacrylic acid ester.

[0022] The raw material monomer (2) may contain other monomers in addition to the styrene-based compound, the vinyl monomer having a carboxy group, and the (meth)acrylic acid ester. 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.

[0023] The raw material monomer (2) preferably contains one or more styrene-based compounds selected from styrene and α-methylstyrene, and one or more vinyl monomers having a carboxy group selected from acrylic acid and methacrylic acid, and more preferably contains styrene, α-methylstyrene, and acrylic acid.

[0024] The content of the styrene compound in the raw material monomer (2) constituting the vinyl resin, or the content of the structural unit derived from the styrene compound in the vinyl resin constituting the vinyl resin segment (CH-2), is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, and is preferably 98% by mass or less, more preferably 96% by mass or less, even more preferably 94% by mass or less, from the viewpoint of improving the hot offset resistance and solid print conformability of the obtained toner. The content of the vinyl monomer having a carboxy group in the raw material monomer (2) constituting the vinyl resin, or the content of the structural unit derived from the vinyl monomer having a carboxy group in the vinyl resin constituting the vinyl resin segment (CH-2) is, from the viewpoint of improving the hot offset resistance and solid print conformability of the obtained toner, preferably 2 mass % or more, more preferably 4 mass % or more, even more preferably 6 mass % or more, and is preferably 50 mass % or less, more preferably 40 mass % or less, even more preferably 30 mass % or less, even more preferably 20 mass % or less.

[0025] The total content of the styrene compound and the vinyl monomer having a carboxy group in the raw material monomer (2) constituting the vinyl resin, or the total content of the structural units derived from the styrene compound and the structural units derived from the vinyl monomer having a carboxy group in the vinyl resin constituting the vinyl resin segment (CH-2), 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 hot offset resistance and solid print conformability of the obtained toner.

[0026] <Production of vinyl resin segment (CH-2)> In the present invention, from the viewpoint of controlling the molecular weight, molecular weight distribution, and copolymerizability of the monomer and improving the hot offset resistance and solid print conformability of the toner obtained, it is preferable that the vinyl resin segment (CH-2) is polymerized in an independent polymerization system separate from the polymerization system of the raw material monomer (1) constituting the polyester resin, in the absence of the polyester resin constituting the polyester segment (CH-1).

[0027] From the viewpoint of ease of control of molecular weight, molecular weight distribution, and copolymerizability of monomers, the vinyl resin segment (CH-2) is preferably formed by bulk polymerization or solution polymerization, more preferably by bulk polymerization. That is, the polymerization of the raw material monomer (2) in step I is preferably bulk polymerization or solution polymerization, more preferably bulk polymerization.

[0028] In the present invention, the term "bulk polymerization" refers to addition polymerization carried out under conditions in which no solvent is substantially 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 polymerization initiator may be used. Examples of the radical polymerization initiator 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 viewpoints of controlling the molecular weight, molecular weight distribution, and copolymerizability and further improving the low-temperature fixing property, hot offset resistance, heat-resistant storage stability, and charging stability, the concentration of the radical polymerization initiator 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 raw material monomers (2) of the vinyl resin, taken as 100% by mass, in other words, it is preferable to carry out the bulk polymerization in the absence of a radical polymerization initiator.

[0029] 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. Radicals generated by the thermal initiation reaction of the raw material monomer (1) under high temperature and pressure equal to or higher than normal pressure function as a polymerization initiator, and therefore addition polymerization can be carried out even under conditions in which the amount of radical polymerization initiator is relatively small, thereby producing a vinyl resin with a narrow molecular weight distribution. Furthermore, in the case of continuous bulk polymerization, in addition to the molecular weight distribution, the monomer composition distribution can be controlled, and a vinyl resin having a narrower monomer composition distribution and a more uniform monomer composition distribution can be obtained, which makes it easier to improve the hot offset resistance and solid image tracking ability of the resulting toner. From the above viewpoints, the temperature of the bulk polymerization is preferably 160° C. or higher, more preferably 190° C. or higher, and is preferably 350° C. or lower, more preferably 320° C. or lower.

[0030] 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. The solution polymerization is preferably carried out by heating the raw material monomer (2) together with a radical polymerization initiator, a polymerization chain transfer agent, etc. in a solvent to carry out addition polymerization. Examples of the radical polymerization initiator include peroxides such as di-tert-butyl peroxide, persulfates such as sodium persulfate, and azo compounds such as 2,2'-azobis(2,4-dimethylvaleronitrile). The amount of the radical polymerization initiator 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 monomer (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.

[0031] The acid value of the vinyl resin segment (CH-2) is, from the viewpoint of compounding with the polyester segment (CH-1) and from the viewpoint of improving the hot offset resistance and solid conformability of the obtained toner, 40 mgKOH / g or more, preferably 45 mgKOH / g or more, more preferably 50 mgKOH / g or more, and 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.

[0032] From the viewpoint of improving the hot offset resistance and solid image tracking ability of the resulting toner, the weight average molecular weight of the vinyl resin segment (CH-2) 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, even more preferably 20,000 or less, and even more preferably 10,000 or less. The weight average molecular weight of the vinyl resin segment (CH-2) can be adjusted by the polymerization temperature and polymerization time.

[0033] From the viewpoint of improving the hot offset resistance and solid print conformability of the resulting toner, the glass transition temperature of the vinyl resin segment (CH-2) is preferably 40° C. or higher, more preferably 45° C. or higher, and is preferably 120° C. or lower, more preferably 90° C. or lower, even more preferably 70° C. or lower, and even more preferably 55° C. or lower. From the viewpoint of improving the hot offset resistance and solid conformability of the resulting toner, the softening point of the vinyl resin segment (CH-2) is preferably 90° C. or higher, more preferably 100° C. or higher, even more preferably 105° C. or higher, and is preferably 160° C. or lower, more preferably 140° C. or lower, and even more preferably 120° C. or lower. Among these, from the viewpoint of improving the hot offset resistance and solid conformability of the resulting toner, it is more preferable that the vinyl resin segment (CH-2) has a glass transition temperature of 45° C. or higher and a softening point of 105° C. or higher. The acid value, weight average molecular weight, glass transition temperature, and softening point of the vinyl resin can be measured by the methods described in the Examples.

[0034] [Polyester segment (CH-1)] The polyester segment (CH-1) of the amorphous composite resin (CH) is preferably composed of a polyester resin which is a polycondensation product of an alcohol component (1-al) and a carboxylic acid component (1-ac) as the raw material monomer (1). The alcohol component (1-al) and the carboxylic acid component (1-ac) contained in the polyester resin are described below.

[0035] <Alcohol component (1-al)> The alcohol component (1-al) may be an aliphatic diol, an alicyclic diol, an aromatic diol, or a polyhydric alcohol having three or more valences. The alcohol component (1-al) may be used alone or in combination of two or more kinds.

[0036] The aliphatic diol preferably has 2 or more carbon atoms, and preferably has 18 or less, more preferably 14 or less, even more preferably 10 or less, and even more preferably 6 or less. Examples of aliphatic diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 2,3-butanediol, neopentyl glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol, and polytetramethylene glycol.

[0037] 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).

[0038] Examples of aromatic diols include alkylene oxide adducts of bisphenol A (2,2-bis(4-hydroxyphenyl)propane) (hereinafter, also referred to as "BPA-AO"). BPA-AO is preferably represented by the formula (I): [ka] [In the formula, OR 11 and R 12 O is an alkyleneoxy group, R 11 and R 12 are each independently an alkylene group having 1 to 4 carbon atoms (preferably an ethylene group or a propylene group), x and y are the average number of moles of alkylene oxide added and are each independently a positive number, and the average value of the sum of x and y is preferably 1 or more, more preferably 1.5 or more, even more preferably 2 or more, and is preferably 16 or less, more preferably 8 or less, and even more preferably 4 or less.

[0039] Examples of BPA-AO include polyoxypropylene(2.2)-2,2-bis(4-hydroxyphenyl)propane and polyoxyethylene(2.2)-2,2-bis(4-hydroxyphenyl)propane. The numerical value in the above parentheses corresponds to the average value of the sum of x and y in the above formula (I).

[0040] Examples of trihydric or higher polyhydric alcohols include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, and 1,3,5-trihydroxymethylbenzene. From the viewpoint of adjusting the molecular weight and softening point of the resin, the alcohol component (1-al) may contain a monohydric alcohol.

[0041] From the viewpoint of improving the hot offset resistance and solid image conformability of the resulting toner, the alcohol component (1-al) preferably contains an aliphatic diol, more preferably contains an aliphatic diol having 2 to 18 carbon atoms, even more preferably contains an aliphatic diol having 2 to 6 carbon atoms, and even more preferably contains one or more selected from 1,2-propanediol and 2,3-butanediol. In addition, from the same viewpoint as above, the content of fatty acid diol in the alcohol component (1-al) is preferably 90 mol% or more, more preferably 95 mol% or more, even more preferably 98 mol% or more, and is 100 mol% or less, even more preferably 100 mol%.

[0042] <Carboxylic acid component (1-ac)> Examples of the carboxylic acid component (1-ac) include dicarboxylic acids, trivalent or higher polyvalent carboxylic acids, and monovalent carboxylic acids. The carboxylic acid component (1-ac) may be used alone or in combination of two or more.

[0043] 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, isophthalic acid, and terephthalic acid. Among these, isophthalic acid and terephthalic acid are preferred, and terephthalic acid is more 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 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 the like. Among these, succinic acid is preferred. An example of the alicyclic dicarboxylic acid is cyclohexanedicarboxylic acid.

[0044] Examples of trivalent or higher polyvalent carboxylic acids include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, and pyromellitic acid.

[0045] Examples of the monocarboxylic acid compound include aliphatic monocarboxylic acids and aromatic monocarboxylic acids. The aliphatic monocarboxylic acid has preferably 1 or more, more preferably 4 or more, and even more preferably 8 or more carbon atoms, and preferably 26 or less, more preferably 22 or less, and even more preferably 18 or less carbon atoms. Examples of the aliphatic monocarboxylic acid include linear, branched, or alicyclic saturated aliphatic monocarboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, pivalic acid, and cyclohexanecarboxylic acid; linear, branched, or alicyclic unsaturated aliphatic monocarboxylic acids such as crotonic acid, isocrotonic acid, myristoleic acid, palmitoleic acid, oleic acid, linoleic acid, linolenic acid, arachidonic acid, abietic acid, palustric acid, and isopimaric acid. Among these, rosin is preferred.

[0046] Examples of rosin include natural resin rosin, unrefined rosin, refined rosin, and modified rosin. Natural rosin is a natural resin obtained from pine trees, and its main components are resin acids such as abietic acid, neoabietic acid, palustric acid, pimaric acid, isopimaric acid, sandaracopimaric acid, dehydroabietic acid, etc., and mixtures of these. Types of natural rosin include tall rosin obtained from tall oil obtained as a by-product in the pulp manufacturing process, gum rosin obtained from raw pine resin, and wood rosin obtained from pine stumps. Unrefined rosin is rosin that contains a large amount of impurities before purification, while refined rosin is rosin whose impurities have been reduced by a purification process. The main impurities include 2-methylpropane, acetaldehyde, 3-methyl-2-butanone, 2-methylpropanoic acid, butanoic acid, pentanoic acid, n-hexanal, octane, hexanoic acid, benzaldehyde, 2-pentylfuran, 2,6-dimethylcyclohexanone, 1-methyl-2-(1-methylethyl)benzene, 3,5-dimethyl-2-cyclohexene, 4-(1-methylethyl)benzaldehyde, etc. Modified rosin is obtained by addition reaction of rosin whose main components are abietic acid, neoabietic acid, palustric acid, pimaric acid, isopimaric acid, sandaracopimaric acid, dehydroabietic acid, and lepopimaric acid with acrylic acid, methacrylic acid, fumaric acid, maleic acid, etc. Specifically, it is obtained by subjecting lepopimaric acid, abietic acid, neoabietic acid, and palustric acid, which have conjugated double bonds among the main components of rosin, to a Diels-Alder reaction under heating with a compound having an unsaturated bond, such as acrylic acid, methacrylic acid, fumaric acid, or maleic acid. In the present invention, the rosin is preferably purified rosin.

[0047] The aromatic monocarboxylic acid preferably has 6 or more and 12 or less carbon atoms. Examples of aromatic monocarboxylic acids include benzoic acid, benzoic acids substituted with an alkyl group having 1 to 4 carbon atoms, such as toluic acid, ethylbenzoic acid, propylbenzoic acid, and tertiary butylbenzoic acid, and naphthoic acid. Among these, benzoic acid is preferred.

[0048] In the present invention, from the viewpoint of improving the hot offset resistance and solid print conformability of the resulting toner, the carboxylic acid component (1-ac) preferably contains a dicarboxylic acid, more preferably contains one or more selected from aliphatic dicarboxylic acids and aromatic dicarboxylic acids, even more preferably contains one or more selected from terephthalic acid and succinic acid, and even more preferably contains terephthalic acid and succinic acid.

[0049] Furthermore, in the present invention, from the viewpoint of improving the hot offset resistance and solid print conformability of the toner obtained, the carboxylic acid component (1-ac) preferably contains a monocarboxylic acid, more preferably contains one or more selected from an aliphatic monocarboxylic acid and an aromatic monocarboxylic acid, further preferably contains one or more selected from rosin and benzoic acid, and further preferably contains rosin.

[0050] The equivalent ratio of the carboxyl group (COOH group) of the carboxylic acid component (1-ac) to the hydroxyl group (OH group) of the alcohol component (1-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.

[0051] <Production of polyester segment (CH-1)> The polyester resin is preferably produced, for example, by a polycondensation reaction of raw material monomer (1) containing an alcohol component (1-al) and a carboxylic acid component (1-ac). From the viewpoint of improving the hot offset resistance and solid-image conformability of the resulting toner, the polycondensation reaction is more preferably carried out according to the following step I'. Step I': A step of obtaining a polyester resin by polymerizing raw material monomer (1) in a polymerization system independent of the polymerization system of raw material monomer (2) constituting the vinyl resin constituting the vinyl resin segment (CH-2) in the absence of the vinyl resin constituting the vinyl resin segment (CH-2).

[0052] 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 (1); 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). 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 per 100 parts by mass of the raw material monomer (1). 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 160° C. or higher, even more preferably 180° 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.

[0053] The mass ratio of the polyester segment (CH-1) to the vinyl resin segment (CH-2) in the amorphous composite resin (CH) [polyester segment (CH-1) / vinyl resin segment (CH-2)], or the mass ratio of the total amount of raw material monomers (1) constituting the polyester segment (CH-1) to the total amount of raw material monomers (2) constituting the vinyl resin segment (CH-2) [total amount of raw material monomers (1) / total amount of raw material monomers (2)] is preferably 30 / 70 or more, more preferably 50 / 50 or more, even more preferably 60 / 40 or more, and is preferably 98 / 2 or less, more preferably 95 / 5 or less, even more preferably 90 / 10 or less, from the viewpoint of improving the dispersibility of the vinyl resin segment (CH-2) and improving the hot offset resistance and solid followability of the obtained toner.

[0054] The content of the polyester segment (CH-1) in the amorphous composite resin (CH) is preferably 30 mass% or more, more preferably 50 mass% or more, and even more preferably 55 mass% or more, based on the total amount of the polyester segment (CH-1) and the vinyl resin segment (CH-2), and is preferably 98 mass% or less, more preferably 95 mass% or less, and even more preferably 90 mass% or less.

[0055] The content of the vinyl resin segment (CH-2) in the amorphous composite resin (CH) is preferably 2 mass% or more, more preferably 5 mass% or more, even more preferably 10 mass% or more, and is preferably 70 mass% or less, more preferably 50 mass% or less, even more preferably 45 mass% or less, based on the total amount of the polyester segment (CH-1) and the vinyl resin segment (CH-2).

[0056] The total amount of the polyester segment (CH-1) and the vinyl resin segment (CH-2) in the amorphous composite resin (CH) is preferably 80 mass% or more, more preferably 90 mass% or more, even more preferably 95 mass% or more, and is 100 mass% or less, and even more preferably 100 mass%.

[0057] The above amount is calculated based on the ratio of the amounts of raw material monomers and radical polymerization initiator for the polyester segment (CH-1) and vinyl resin segment (CH-2), and does not include the amount of dehydration (theoretical amount of reaction water) due to polycondensation in the polyester segment (CH-1), etc. When a radical polymerization initiator is used, the mass of the radical polymerization initiator is included in the addition polymerization resin segment for the calculation.

[0058] The hydroxyl value of the amorphous composite resin (CH) of the present invention is, from the viewpoint of improving the hot offset resistance and solid image tracking ability of the toner obtained, 20 mgKOH / g or less, preferably 15 mgKOH / g or less, more preferably 10 mgKOH / g or less, even more preferably 8 mgKOH / g or less, and is preferably 1 mgKOH / g or more, more preferably 2 mgKOH / g or more, even more preferably 3 mgKOH / g or more.

[0059] The softening point of the amorphous composite resin (CH) of the present invention is preferably 70° C. or higher, more preferably 80° C. or higher, and even more preferably 90° C. or higher, and is preferably 150° C. or lower, more preferably 130° C. or lower, and even more preferably 110° C. or lower. The glass transition temperature of the amorphous composite resin (CH) of the present invention is preferably 40° C. or higher, more preferably 50° C. or higher, and preferably 80° C. or lower, more preferably 70° C. or lower, and further preferably 60° C. or lower. The acid value of the amorphous composite resin (CH) of the present invention is preferably 60 mgKOH / g or less, more preferably 50 mgKOH / g or less, even more preferably 40 mgKOH / g or less, even more preferably 30 mgKOH / g or less, and is preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g or more, even more preferably 15 mgKOH / g or more, even more preferably 20 mgKOH / g or more. The softening point, glass transition temperature and acid value of the amorphous composite resin (CH) of the present invention can be easily adjusted to these ranges by adjusting the types and amounts of raw material monomers, the amount of radical polymerization initiator, the amount of catalyst, etc., or by selecting reaction conditions.

[0060] (Method of producing resin particles) In the present invention, as the resin particles, particles containing an amorphous composite resin (CH) (hereinafter also referred to as "amorphous composite resin (CH) particles") are used. In addition, when the resin particles further contain a resin other than the amorphous composite resin (CH), particles containing an amorphous composite resin (CH) and particles containing a resin other than the amorphous composite resin (CH) may be used in combination, or resin particles containing an amorphous composite resin (CH) and a resin other than the amorphous composite resin (CH) in the same particle may be used. In the present invention, it is preferable to use particles containing an amorphous composite resin (CH) and particles containing a resin other than the amorphous composite resin (CH) in combination. Examples of the resin other than the amorphous composite resin (CH) include a crystalline polyester resin and an amorphous polyester resin. In the following description, particles containing an amorphous composite resin (CH) will be described.

[0061] In the present invention, the dispersion of amorphous composite resin (CH) particles can be obtained by dispersing the amorphous composite resin (CH) in an aqueous medium. The aqueous medium is preferably one containing water as a main component, and from the viewpoint of improving the dispersion stability of the dispersion liquid of the amorphous composite resin (CH) particles and from the viewpoint of environmental friendliness, the content of water in the aqueous medium is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and 100% by mass or less, and even more preferably 100% by mass. Deionized water or distilled water is preferable as the water. Examples of components other than water that can be contained in the aqueous medium include organic solvents that dissolve in water, such as alkyl alcohols having 1 to 5 carbon atoms; dialkyl ketones having a total carbon number of 3 to 5, such as acetone and methyl ethyl ketone; and cyclic ethers such as tetrahydrofuran. Among these, methyl ethyl ketone is preferable.

[0062] The dispersion can be carried out by a known method, but is preferably carried out by a phase inversion emulsification method, for example, a method in which an aqueous medium is added to an organic solvent solution of the amorphous composite resin (CH) or a molten amorphous composite resin (CH) to carry out phase inversion emulsification.

[0063] The organic solvent used for phase inversion emulsification is not particularly limited as long as it dissolves the amorphous composite resin (CH), and examples thereof include methyl ethyl ketone. It is preferable to add a neutralizing agent to the organic solvent solution of the amorphous composite resin (CH). Examples of the neutralizing agent include basic substances. Examples of the basic substances include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, and nitrogen-containing basic substances such as ammonia, trimethylamine, and diethanolamine. The degree of neutralization of the amorphous composite resin (CH) 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 (CH) can be determined by the following formula. Degree of neutralization (mol%)=[{weight of neutralizing agent added (g) / equivalent weight of neutralizing agent} / {acid value of amorphous composite resin (CH) (mgKOH / g)×weight of amorphous composite resin (CH) (g)} / (56×1000)]×100

[0064] The phase inversion emulsification is carried out by gradually adding an aqueous medium while stirring an organic solvent solution of the amorphous composite resin (CH) or a molten amorphous composite resin (CH). From the viewpoint of improving the dispersion stability of the resin particles, the temperature of the organic solvent solution when the aqueous medium is added is preferably not less than the glass transition temperature of the amorphous composite resin (CH), more preferably not less than 50° C., even more preferably not less than 60° 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.

[0065] After the phase inversion emulsification, if necessary, the organic solvent may be removed from the obtained dispersion by distillation, etc. In this case, the amount of the remaining organic solvent in the dispersion is preferably 1% by mass or less, more preferably 0.5% by mass or less, and even more preferably substantially 0% by mass.

[0066] Volume median particle size D of amorphous composite resin (CH) particles in the dispersion 50 From the viewpoint of improving the hot offset resistance and solid image conformability of the obtained toner, is preferably 50 nm or more, more preferably 70 nm or more, even more preferably 80 nm or more, even more preferably 90 nm or more, and is preferably 500 nm or less, more preferably 300 nm or less, even more preferably 200 nm or less, even more preferably 150 nm or less. Volume median particle size D 50 is determined by the method described in the Examples below.

[0067] (Colorant particles) In the present invention, it is preferable that the colorant is added in the form of colorant particles, and in step 1, these are aggregated together with the amorphous composite resin (CH) particles.

[0068] The colorant dispersion is preferably obtained by dispersing the colorant and the aqueous medium using a dispersing machine such as a homogenizer, an ultrasonic dispersing machine, etc. From the viewpoint of improving the dispersion stability of the colorant, the dispersion is more preferably carried out in the presence of a surfactant. Examples of colorants include carbon black, phthalocyanine blue (e.g., Pigment Blue 15:3), permanent brown FG, brilliant fast scarlet, pigment green B, rhodamine-B base, solvent red 49, solvent red 146, solvent blue 35, quinacridone, carmine 6B, and disazo yellow (e.g., Pigment Yellow 155). The toner may be either a black toner or a color toner other than black. Examples of surfactants used in the colorant dispersion include anionic surfactants such as alkylbenzene sulfonates and alkyl ether sulfates; nonionic surfactants such as polyoxyethylene alkyl ethers and polyoxyethylene alkenyl ethers; and cationic surfactants such as quaternary ammonium salts, such as alkylbenzyldimethylammonium chloride and alkyltrimethylammonium chloride.

[0069] The content of the colorant in the toner particles is preferably 1% by mass or more, more preferably 2% by mass or more, and preferably 20% by mass or less, more preferably 15% by mass or less.

[0070] (Release agent) The aggregation of the resin particles and the colorant particles is preferably carried out in the presence of a release agent. Examples of the release agent include polypropylene wax, polyethylene wax, polypropylene-polyethylene copolymer wax, hydrocarbon waxes such as microcrystalline wax, paraffin wax, Fischer-Tropsch wax, and oxides thereof, ester waxes such as carnauba wax, montan wax, and deacidified waxes thereof, and fatty acid ester wax, fatty acid amides, fatty acids, higher alcohols, and fatty acid metal salts. These may be used alone or in combination of two or more. Among these, the release agent is preferably a hydrocarbon wax, and more preferably a paraffin wax.

[0071] The melting point of the release agent is preferably 60° C. or higher, more preferably 65° C. or higher, and even more preferably 70° C. or higher, and is preferably 150° C. or lower, more preferably 130° C. or lower, and even more preferably 100° C. or lower.

[0072] The content of the release agent in the toner particles is preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 2% by mass or more, and is preferably 10% by mass or less, and more preferably 8% by mass or less.

[0073] (Charge control agent) The aggregation of the resin particles and the colorant particles is preferably carried out in the presence of a charge control agent. The charge control agent may contain either a positively chargeable charge control agent or a negatively chargeable charge control agent. Examples of the positively charged charge control agent include nigrosine dyes such as "Nigrosine Base EX", "Oil Black BS", "Oil Black SO", "Bontron N-01", "Bontron N-04", "Bontron N-07", "Bontron N-09", "Bontron N-11", and "Bontron N-79" (all manufactured by Orient Chemical Industry Co., Ltd.); triphenylmethane dyes containing tertiary amines as side chains, quaternary ammonium salt compounds such as "Bontron P-51" (manufactured by Orient Chemical Industry Co., Ltd.), cetyltrimethylammonium bromide, "COPY CHARGE PX VP435" (manufactured by Clariant); polyamine resins such as "AFP-B" (manufactured by Orient Chemical Industry Co., Ltd.); imidazole derivatives such as "PLZ-2001" and "PLZ-8001" (manufactured by Shikoku Chemical Industry Co., Ltd.); and styrene-acrylic resins such as "FCA-701PT" (manufactured by Fujikura Chemical Industry Co., Ltd.).

[0074] Examples of negatively chargeable charge control agents include metal-containing azo dyes such as "Varifast Black 3804", "Bontron S-31", "Bontron S-32", "Bontron S-34", and "Bontron S-36" (all manufactured by Orient Chemical Industry Co., Ltd.), "Aizen Spiron Black TRH", and "T-77" (manufactured by Hodogaya Chemical Industry Co., Ltd.); metal compounds of benzilic acid compounds such as "LR-147" and "LR-297" (both manufactured by Nippon Carlit Co., Ltd.); metal compounds of salicylic acid compounds such as "Bontron E-81", "Bontron E-84", "Bontron E-88", and "Bontron E-304" (all manufactured by Orient Chemical Industry Co., Ltd.), and "TN-105" (manufactured by Hodogaya Chemical Industry Co., Ltd.); copper phthalocyanine dyes; quaternary ammonium salts such as "COPY CHARGE NX VP434" (manufactured by Clariant), nitroimidazole derivatives, and organometallic compounds. The charge control agent to be used may be appropriately selected depending on the characteristics of the printer in which the toner is used, the type of colorant, and the like.

[0075] The content of the charge control agent is preferably 0.01 parts by mass or more, more preferably 0.2 parts by mass or more, even more preferably 0.5 parts by mass or more, and is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, even more preferably 3 parts by mass or less, relative to 100 parts by mass of the total amount of the binder resin.

[0076] When other components such as a release agent and a charge control agent are added, they are preferably added as an aqueous dispersion in the same manner as the colorant dispersion.

[0077] In step 1, the aggregation of the amorphous composite resin (CH) in the aqueous medium may be carried out in the presence of other additives in addition to the colorant particles and, if necessary, the release agent and charge control agent. As the aqueous medium, the aqueous medium shown in the method for producing resin particles can be used, and the preferred ranges thereof are also the same. Examples of other additives include magnetic powder, flow improvers, conductivity adjusters, reinforcing fillers such as fibrous substances, antioxidants, antiaging agents, and cleaning improvers.

[0078] [Surfactant] In step 1, when the dispersions of the individual particles are mixed to prepare a mixed dispersion, the process may be carried out in the presence of a surfactant in order to improve the dispersion stability of optional components such as the resin particles, colorant particles, and release agent particles added as necessary. Examples of the surfactant include anionic surfactants such as alkylbenzene sulfonates and alkyl ether sulfates; nonionic surfactants such as polyoxyethylene alkyl ethers and polyoxyethylene alkenyl ethers; and cationic surfactants such as quaternary ammonium salts such as alkylbenzyldimethylammonium chloride and alkyltrimethylammonium chloride. When a surfactant is used, the amount used, for each type of surfactant, is preferably 0.1 parts by mass or more, more preferably 0.2 parts by mass or more, per 100 parts by mass of resin particles, and is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 3 parts by mass or less.

[0079] The resin particle dispersion, the colorant particle dispersion, and the optional components are mixed by a conventional method. In order to efficiently aggregate the particles, a polyvalent metal salt is added as an aggregating agent to the mixed dispersion obtained by the mixing.

[0080] (polyvalent metal salts) In the present invention, the polyvalent metal salt is used as an aggregating agent from the viewpoint of efficiently carrying out aggregation and improving the hot offset resistance and solid print conformability of the resulting toner. Examples of polyvalent metal salts include magnesium chloride, magnesium nitrate, calcium chloride, calcium nitrate, and aluminum chloride. Among these, from the viewpoint of improving the cohesiveness and obtaining uniform toner particles, preferably a polyvalent metal salt having a valence of 2 to 5, more preferably a polyvalent metal salt having a valence of 2 to 3, even more preferably one or more selected from calcium chloride and aluminum chloride, and even more preferably calcium chloride.

[0081] For example, the polyvalent metal salt is added to an amorphous composite resin (CH) dispersion liquid at 0° C. to 40° C., and the amorphous composite resin (CH) is aggregated in an aqueous medium to obtain aggregated particles. Furthermore, from the viewpoint of promoting aggregation, it is preferable to increase the temperature of the dispersion liquid after adding the polyvalent metal salt. The amount of polyvalent metal salt added is preferably 0.05 parts by mass or more, more preferably 0.10 parts by mass or more, even more preferably 0.15 parts by mass or more, and is preferably 1.00 parts by mass or less, more preferably 0.50 parts by mass or less, even more preferably 0.40 parts by mass or less, relative to 100 parts by mass of the total amount of resin in the toner particles.

[0082] The aggregation may be stopped when the aggregated particles grow to a suitable particle size as toner particles. 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.

[0083] (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 0.1 part by mass or more, more preferably 0.5 part by mass or more, and even more preferably 1.0 part by mass or more, relative to 100 parts by mass of the total amount of resin in the toner particles, from the viewpoint of reliably preventing unnecessary aggregation, and is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and even more preferably 5 parts by mass or less, from the viewpoint of reducing residue in the toner.

[0084] Moreover, the step 1 of the present invention preferably includes the following steps 1-1 and 1-2. By carrying out the step 1 through the following steps 1-1 and 1-2, toner particles having a core-shell structure can be obtained. Step 1-1: A step of aggregating resin particles in an aqueous medium in the presence of a polyvalent metal salt to obtain core particles (aggregated particles 1). Step 1-2: A step of aggregating resin particles containing an amorphous composite resin (CH) with respect to the core particles to obtain core-shell particles (aggregated particles 2).

[0085] When the step 1 includes the above steps 1-1 and 1-2, the toner particles have the amorphous composite resin (CH) in the shell. The resin contained in the resin particles in step 1-1 may be any resin commonly used as a core resin in toners, and is preferably an amorphous polyester resin, and more preferably a polyester resin constituting the polyester segment (CH-1) of the above-mentioned amorphous composite resin (CH). Furthermore, when the toner particles contain a colorant, a release agent and other additives, it is preferable to add these additives in step 1-1.

[0086] In addition, when the step 1 includes the above steps 1-1 and 1-2, it is preferable to terminate the aggregation in step 1-2 when the particles containing the amorphous composite resin (CH) have grown to an appropriate particle size as toner particles, and a method of terminating the aggregation by adding the above-mentioned aggregation terminator is preferable. The mass ratio of the amorphous composite resin (CH) (resin forming the shell) to the mass of the resin forming the core [amorphous composite resin (CH) / resin forming the core] is, from the viewpoint of improving the hot offset resistance and solid print conformability of the obtained toner, preferably 1 / 99 or more, more preferably 5 / 95 or more, even more preferably 10 / 90 or more, and is preferably 50 / 50 or less, more preferably 40 / 60 or less, even more preferably 35 / 75 or less.

[0087] <Process 2> In step 2, for example, after the aggregation is stopped, the obtained aggregated particles are fused in an aqueous medium. By fusing the obtained aggregated particles in an aqueous medium, fused particles containing the amorphous composite resin (CH) can be obtained. In step 2, from the viewpoint of improving the fusibility of the aggregated particles, the aggregated particles are preferably 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 resin particles. The holding temperature when fusing the aggregated particles is, from the viewpoint of improving the fusing property of the aggregated particles and improving the productivity of the toner, preferably at least 5° C. higher than the glass transition temperature of the resin, more preferably at least 10° C. higher, and even more preferably at least 15° C. higher, and is preferably not higher than 35° C. higher, and more preferably not higher than 30° C. higher, than the glass transition temperature of the resin. In this case, the time for which the resin is maintained at a temperature equal to or higher than the glass transition temperature is preferably 1 minute or more, more preferably 10 minutes or more, even more preferably 30 minutes or more, and is preferably 240 minutes or less, more preferably 180 minutes or less, even more preferably 120 minutes or less, even more preferably 90 minutes or less. It is preferable to maintain the temperature at the above temperature until the desired circularity is achieved.

[0088] 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 9 μm or less, even more preferably 8 μm or less. 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.

[0089] <Post-processing process> In the present invention, a post-treatment step may be performed after step 2, and the obtained fused particles can be isolated to obtain toner particles. Since the obtained fused particles 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 surfactant added, and therefore it is preferable to wash the product with an aqueous medium at a temperature below the cloud point of the surfactant. It is preferable to wash the product several times. Next, drying is preferably performed. Examples of the drying method include vacuum low-temperature drying, vibration-type fluidized bed drying, spray drying, freeze drying, and flash jet drying.

[0090] <Toner particles> The volume median particle size D of the obtained toner particles 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 9 μm or less, even more preferably 8 μm or less. The circularity of the resulting toner particles is preferably 0.955 or more, more preferably 0.960 or more, and 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.

[0091] In the present invention, the toner particles obtained preferably have a core-shell structure. When the toner particles obtained have a core-shell structure, the solid print conformability and hot offset resistance of the toner obtained are more easily improved. In the present invention, when the toner particles to be obtained have a core-shell structure, the above step 1 preferably includes the above steps 1-1 and 1-2. In the present invention, when the toner particles obtained have a core-shell structure, it is preferable that the amorphous composite resin (CH) forms the shell of the core-shell structure from the viewpoint of improving the hot offset resistance and solid followability of the obtained toner. The core resin may be any resin that is generally used in toners, and is preferably an amorphous polyester resin, and more preferably a polyester resin that constitutes the polyester segment (CH-1) of the above-mentioned amorphous composite resin (CH).

[0092] <Toner> The toner 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.

[0093] (External additives) Examples of the external additive include inorganic fine particles such as hydrophobic silica, titanium oxide, alumina, cerium oxide, and carbon black, and polymer fine particles such as polycarbonate, polymethyl methacrylate, and silicone resin. Among these, hydrophobic silica is preferred. The external additive may be used alone or in combination with two or more kinds. In addition, two or more kinds of hydrophobic silica having different particle sizes may be used. When the toner particles are surface-treated using an external additive, the amount of the external additive added is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and preferably 5 parts by mass or less, more preferably 4.5 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.

[0094] Toners are used, for example, in electrophotographic printing to develop electrostatic images. The toners can be used, for example, as one-component developers or mixed with a carrier to form two-component developers. EXAMPLES

[0095] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Each property value was measured and evaluated by the following methods.

[0096] [Measurement method] <Resin 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.

[0097] <Glass transition temperature of resin> Using a differential scanning calorimeter "Q-100" (manufactured by TA Instruments Japan Co., Ltd.), 0.01 to 0.02 g of sample was weighed into an aluminum pan, and the sample was heated from room temperature (20°C) to 100°C at a heating rate of 10°C / min, and then cooled from 100°C to 0°C at a heating rate of 10°C / min. Next, the sample was heated to 180°C at a heating rate of 10°C / min, and the endothermic peak was measured. The temperature at the intersection of the extension of the baseline below the maximum endothermic peak temperature and the tangent line showing the maximum slope from the rising part of the peak to the top of the peak was taken as the glass transition temperature.

[0098] <Acid value of resin> Measurement was performed based on the method of JIS K 0070: 1992. However, the measurement solvent was changed from the mixed solvent of ethanol and ether specified in JIS K 0070: 1992 to a mixed solvent of acetone and toluene (acetone:toluene = 1:1 (volume ratio)).

[0099] <Hydroxyl value of resin> Measurements were performed according to the method of JIS K 0070: 1992. However, the measurement solvent was changed from the mixed solvent of ethanol and ether specified in JIS K 0070: 1992 to tetrahydrofuran.

[0100] <Number average molecular weight and weight average molecular weight of resin> The following measuring device and analytical column were used, tetrahydrofuran was used as the eluent at a flow rate of 1 mL per minute, and the column was stabilized in a thermostatic bath at 40°C. 100 μL of the sample solution was injected into the column for measurement. The molecular weight of the sample was calculated based on a calibration curve that had been prepared in advance. The calibration curve used here included several types of monodisperse polystyrene (Tosoh Corporation's "A-500" (Mw: 5.0 × 10 2 ), "A-1000" (Mw:1.01×10 3 ), "A-2500" (Mw:2.63×10 3 ), "A-5000" (Mw:5.97×10 3 ), "F-1" (Mw:1.02×10 4 ), "F-2" (Mw:1.81×10 4 ), "F-4" (Mw:3.97×10 4 ), "F-10" (Mw:9.64×10 4 ), "F-20" (Mw:1.90×10 5 ), "F-40" (Mw:4.27×10 5 ), "F-80" (Mw:7.06×10 5 ), "F-128" (Mw:1.09×10 6 )) was used as a standard sample. The numbers in parentheses indicate the molecular weight. Measuring device: "HLC-8220GPC" (Tosoh Corporation) Analytical column: "GMHXL" + "G3000HXL" (manufactured by Tosoh Corporation)

[0101] <Resin 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)).

[0102] <Acid value of vinyl resin segment part of resin E-1> The acid value of the vinyl resin segment obtained was determined by the following method. (1) Separation of vinyl resin segments Resin E-1 was dissolved in tetrahydrofuran to a concentration of 5 g / 100 mL, and 10 g of 5% aqueous sodium hydroxide solution was added and mixed to hydrolyze the polyester portion. Then, ethanol was added little by little to cause reprecipitation, and only the vinyl resin segment portion was separated. (2) Measurement of the acid value of vinyl resin segments Measurements were performed according to the method of JIS K 0070:1992, except that the measurement solvent was changed from the ethanol and ether mixture specified in JIS K 0070 to a mixture of acetone and toluene (acetone:toluene = 1:1 (volume ratio)).

[0103] <Solid content concentration of resin particle dispersion, colorant dispersion, release agent dispersion, and charge control agent 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%)

[0104] <Volume median particle size (D 50 )> The volume median particle size (D 50 ) was measured. Measurement equipment: Laser diffraction particle size measuring instrument "LA-920" (manufactured by Horiba Ltd.) Measurement conditions: Add distilled water to the measurement cell and measure the volume median particle size (D 50 ) was measured.

[0105] <Circularity of toner particles> The circularity of the toner 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

[0106] [Production of vinyl resins] Production Examples A1 to A3 (Production of Resins A-1 to A-3) The raw material monomers for the vinyl resins shown in Table 1 were placed in an autoclave equipped with a stainless steel stirring rod, and the raw material monomers were polymerized under pressurized and heated conditions (300°C) for 2 hours. The pressure and temperature were returned to normal, and the vinyl resins that precipitated were collected, yielding vinyl resins A-1 to A-3.

[0107] Manufacturing Example A4 (Manufacturing of Resin A-4) 2 liters of xylene was placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a downflow condenser, a dropping funnel, and a nitrogen inlet tube. In addition, the raw material monomers and radical polymerization initiator of the vinyl resin shown in Table 1 were placed in the dropping funnel equipped on the four-neck flask. Then, the xylene in the four-neck flask was heated to 135°C under a nitrogen atmosphere, and the mixture of the raw material monomers and the radical polymerization initiator was dropped into the xylene from the dropping funnel over 1 hour. The temperature was further raised to 200°C and maintained at 200°C for 2 hours. Then, the mixture was further maintained under a reduced pressure of 8 kPa for 1 hour to remove the xylene, and vinyl resin A-4 was obtained.

[0108] [Table 1]

[0109] [Production of amorphous composite resin] Production Examples C1 to C8 (Production of Amorphous Composite Resins CH-1 to CH-8) Among the raw materials of the polyester segment shown in Table 2, raw materials other than succinic acid and an esterification catalyst 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 100 ° C. was passed, and a nitrogen inlet tube. In a mantle heater in a nitrogen atmosphere, the temperature was kept at 180 ° C. for 1 hour, and then the temperature was increased from 180 ° C. to 230 ° C. at 10 ° C. / h, and then polycondensation reaction was carried out at 230 ° C. for 10 hours, and further reaction was carried out at 230 ° C. and 8.0 kPa for 1 hour. After cooling to 180 ° C., succinic acid was added and the temperature was raised to 210 ° C. over 2 hours. After that, reaction was carried out at 210 ° C. for 1 hour, and then reaction was carried out under reduced pressure of 40 kPa for 2 hours. Then, at 210°C, the vinyl resins shown in Table 2 were added as raw materials for the vinyl resin segment, melted and mixed, and reacted at 210°C for 4 hours. Thereafter, the reaction was continued under a reduced pressure of 8.0 kPa until the softening point reached the temperature shown in Table 2, thereby obtaining composite resins CH-1 to CH-8.

[0110] Manufacturing example D1 (Production of Resin D-1) Among the raw materials of the polyester segment shown in Table 2, raw materials other than succinic acid and an esterification catalyst 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 100 ° C. was passed, and a nitrogen inlet tube. In a mantle heater in a nitrogen atmosphere, the temperature was kept at 180 ° C. for 1 hour, and then the temperature was increased from 180 ° C. to 230 ° C. at 10 ° C. / h, and then polycondensation reaction was carried out at 230 ° C. for 10 hours, and further reaction was carried out at 230 ° C. and 8.0 kPa for 1 hour. After cooling to 180 ° C., succinic acid was added and the temperature was raised to 210 ° C. over 2 hours. After that, reaction was carried out at 210 ° C. for 1 hour, and reaction was carried out under reduced pressure of 40 kPa until the softening point reached the temperature shown in Table 2, to obtain resin D-1.

[0111] Production Example E1 (Production of Composite Resin E-1) Among the raw materials of the polyester segment shown in Table 3, raw materials other than succinic acid and an esterification catalyst 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 100 ° C. was passed, and a nitrogen inlet tube, and after keeping at 180 ° C. for 1 hour in a mantle heater in a nitrogen atmosphere, the temperature was increased from 180 ° C. to 230 ° C. at 10 ° C. / h, and then polycondensation reaction was carried out at 230 ° C. for 10 hours, and further reaction was carried out at 230 ° C. and 8.0 kPa for 1 hour. After cooling to 160 ° C., a mixed solution of raw material monomers and radical polymerization initiators of the vinyl resin segment shown in Table 3 was dropped over 1 hour. After that, it was held at 160 ° C. for 30 minutes, heated to 200 ° C., and further reacted under reduced pressure of 8 kPa for 1 hour, and then cooled to 180 ° C. Then, succinic acid was added, and the temperature was raised to 210 ° C. over 2 hours. After that, the mixture was reacted at 210° C. for 1 hour, and then reacted under a reduced pressure of 40 kPa until the mixture reached a desired softening point, to obtain a composite resin E-1.

[0112] [Table 2]

[0113] [Table 3]

[0114] [Production of aqueous resin dispersion] Production Example c1 (Production of Water-Based Dispersion of Composite Resin ch-1) 100g of amorphous composite resin CH-1, 100g of methyl ethyl ketone, and 16.7g (4.5% by mass relative to 100g of resin) of anionic surfactant "EMAL E27C" (Kao Corporation) were added to a 3L vessel equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen inlet tube, and dissolved at 73°C for 2 hours. A 5% by mass aqueous solution of sodium hydroxide was added to the resulting solution so that the degree of neutralization was 70 mol% relative to the acid value of the resin, and the mixture was stirred for 30 minutes. While maintaining the temperature at 73°C, 675g of deionized water was added over 77 minutes while stirring at 280r / min (circumferential speed 88m / min), and phase inversion emulsification was performed. While continuing to maintain the temperature at 73°C, methyl ethyl ketone was distilled off under reduced pressure. Thereafter, the aqueous dispersion was cooled to 30°C while stirring at 280r / min (circumferential speed 88m / min). Thereafter, the solids concentration of the dispersion was measured, and deionized water was added to make it 20 mass%, thereby obtaining an aqueous dispersion ch-1 of an amorphous composite resin in which amorphous composite resin (CH) particles are dispersed in an aqueous medium.

[0115] Production Examples c2 to c8, d1 and e1 (Production of Resin Aqueous Dispersions ch-2 to ch-8, d-1 and e-1) In Production Example c1, except that the resin was changed to the type of amorphous composite resin, core resin, or composite resin shown in Table 4, the same procedures as in Production Example c1 were followed to obtain aqueous dispersions ch-2 to ch-8, d-1, and e-1 of each resin.

[0116] [Table 4]

[0117] [Preparation of each dispersion] Preparation Example 1 (Production of Colorant Dispersion) 50 g of copper phthalocyanine "ECB-301" (Dainichiseika Color & Chemicals Co., Ltd., Phthalocyanine Blue), 5 g of nonionic surfactant "Emulgen 150" (polyoxyethylene lauryl ether, Kao Corporation) and 200 g of deionized water were mixed and dispersed for 10 minutes using a homogenizer to obtain a colorant dispersion liquid containing colorant particles. 50 ) was 120 nm and the solid content was 22% by mass.

[0118] Preparation Example 2 (Production of Charge Control Agent Dispersion) 50 g of the salicylic acid compound "Bontron E-84" (manufactured by Orient Chemical Industries Co., Ltd.) as a charge control agent, 5 g of "Emulgen 150" (manufactured by Kao Corporation) as a nonionic surfactant, and 200 g of deionized water were mixed, and dispersed for 10 minutes using glass beads and a sand grinder to obtain a charge control agent dispersion liquid containing charge control agent particles. The volume median particle diameter (D 50 ) was 400 nm and the solid content was 22% by mass.

[0119] Preparation Example 3 (Production of Release Agent Dispersion) 50 g of paraffin wax "HNP9" (manufactured by Nippon Seiro Co., Ltd., melting point 75°C), 5 g of cationic surfactant "Sanisol (registered trademark) B50" (manufactured by Kao Corporation, alkylbenzyldimethylammonium chloride) and 200 g of deionized water were heated to 95°C and dispersed for 30 minutes using an ultrasonic homogenizer (manufactured by Dr. Hielscher Co., Ltd., product name: "UP-400S") at an output of 350 W to obtain a release agent dispersion containing release agent particles. The volume median particle diameter (D 50 ) was 550 nm and the solids concentration was 22% by mass.

[0120] [Production of toner for developing electrostatic images] Example 1 240g of the aqueous dispersion d-1 of the core resin, 8g of the colorant dispersion, 20g of the release agent dispersion, 2g of the charge control agent dispersion, and 52g of deionized water were placed in a 2L container, and 150g of a 0.1% by mass calcium chloride aqueous solution was added dropwise at 20°C over 30 minutes while stirring at 100r / min (circumferential speed 31m / min) with an anchor type stirrer. The temperature was then raised to 50°C while stirring. The volume median particle size (D 50) was kept at 50°C until it reached 5μm. Then, 60g of an aqueous dispersion of amorphous composite resin ch-1 was immediately added and stirred to obtain a dispersion of aggregated particles. Then, a dilution solution of 4.2g of anionic surfactant "EMAL E27C" (Kao Corporation, solid content 27% by mass) diluted with 37g of deionized water was added as an aggregation stopper. The temperature was then raised to 80°C, and the mixture was kept at 80°C for 1 hour after reaching 80°C, and the heating was then terminated. After this, fused particles were formed, and the mixture was gradually cooled to 20°C, filtered through a 150 mesh (150 micrometer opening) wire net, suction filtered, washed, and dried to obtain toner particles. Next, 1.0 part by mass of hydrophobic silica "NAX-50" (manufactured by Nippon Aerosil Co., Ltd., number average particle diameter 40 nm), 0.6 part by mass of hydrophobic silica "R972" (manufactured by Nippon Aerosil Co., Ltd., number average particle diameter 16 nm), and 0.5 part by mass of titanium oxide "JMT-150IB" (manufactured by Teika Corporation, number average particle diameter 15 nm) per 100 parts by mass of the above toner particles were added to a 10L Henschel mixer (manufactured by Nippon Coke and Engineering Co., Ltd.) equipped with ST, A0 stirring blades, and stirred at 3000 rpm for 2 minutes to obtain the toner of Example 1.

[0121] Examples 2 to 9, Comparative Examples 1 to 2 The toners of each of the examples and comparative examples were obtained in the same manner as in Example 1, except that the types and ratios of the aqueous dispersion of resin and the aggregating agent in Example 1 were changed to those shown in Table 5.

[0122] [Toner Evaluation] <Hot offset resistance> Each toner was mounted on a copy machine "AR-505" (manufactured by Sharp Corporation) with an improved fixing machine that allows fixing outside the machine, and a printout was obtained in an unfixed state (print area: 2 cm x 12 cm, adhesion amount: 0.5 mg / cm2). Then, using a fixing machine (fixing speed 300 mm / sec) adjusted to a total fixing pressure of 40 kgf, the temperature of the fixing roll was raised from 80°C to 240°C in 5°C increments, and a fixing test was performed on the unfixed printout at each temperature. The fixed image obtained above was visually judged, and the lowest temperature of the fixing roll at which hot offset was observed was taken as the hot offset temperature. Note that "CopyBond SF-70NA" (manufactured by Sharp Corporation, 75 g / m2) was used as the fixing paper. The higher the hot offset temperature, the better the hot offset resistance. These results are shown in Table 5.

[0123] <Contactability> It is generally known that the more spherical a toner is, the higher its fluidity is, and it is known that the higher the fluidity of the toner is, the better the solid print conformability is evaluated. Using a commercially available printer "Microline (registered trademark) 5400" (manufactured by Oki Data Corporation) on high-quality paper "J paper A4 size" (manufactured by Fuji Xerox Co., Ltd.), the amount of toner attached on the paper was 0.42 to 0.48 mg / cm 2 Three solid images were output as follows. The image density was evaluated as the difference between the image density at the leading edge of the first solid image and the image density at the trailing edge of the third solid image. Image density 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).

[0124] [Table 5]

[0125] From the results of the Examples and Comparative Examples in Table 5, it was confirmed that the toner obtained by the toner manufacturing method of the present invention is excellent in solid print conformability and hot offset resistance.

Claims

1. A method for producing a toner, comprising aggregating and fusing particles containing an amorphous composite resin (CH) and colorant particles in an aqueous medium in the presence of a polyvalent metal salt to form toner particles, the amorphous composite resin (CH) contains a polyester segment (CH-1) and a vinyl resin segment (CH-2) which is an addition polymer of a monomer component containing a styrene-based compound, and the polyester segment (CH-1) and the vinyl resin segment (CH-2) are composited by a polymer reaction; the acid value of the vinyl resin constituting the vinyl resin segment (CH-2) is 40 mgKOH / g or more; The hydroxyl value of the amorphous composite resin (CH) is 20 mgKOH / g or less. Toner manufacturing method.

2. 2. The method for producing a toner according to claim 1, wherein in the polyester segment (CH-1), the content of the fatty acid diol in the alcohol component is 90 mol % or more.

3. 2. The method for producing a toner according to claim 1, wherein in the polyester segment (CH-1), a carboxylic acid component contains rosin.

4. 2. The method for producing a toner according to claim 1, wherein in the vinyl resin segment (CH-2), the styrene compound includes styrene and α-methylstyrene.

5. 2. The method for producing a toner according to claim 1, wherein in the vinyl resin segment (CH-2), the monomer component includes a vinyl monomer having a carboxy group.

6. The method for producing a toner according to any one of claims 1 to 5, wherein the toner particles have a core-shell structure.

7. The method for producing a toner according to claim 6 , wherein the amorphous composite resin (CH) forms a shell of a core-shell structure in the toner particles.