Method for producing toner for developing electrostatic images

Abstract

To provide an electrostatic image developing toner manufacturing method which enable production of an electrostatic image developing toner that suppresses color streaks or color spots.SOLUTION: An electrostatic image developing toner manufacturing method is provided, comprising a first step of obtaining toner particles containing an amorphous polyester resin, crystalline polyester resin, and vinyl resin by a wet manufacturing method, and a second step of bringing the toner particles into contact with acidic water.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] Patent Document 1 proposes "a method for producing a toner for developing electrostatic images using a wet process in which colored resin particles are produced by granulation in water or an organic solvent, or a mixed solvent thereof, and the colored resin particles are washed and dried to produce toner particles, the method comprising filtering the colored resin particles from the liquid medium by a cake washing method, washing the colored resin particles while they are held in a cake state with water, and further carrying out an ion exchange reaction of acidic groups on the toner surface." [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-279598 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a method for producing a toner for developing electrostatic images, the method including a step of obtaining toner particles containing an amorphous polyester resin, a crystalline polyester resin, and a vinyl resin by a wet process, which method produces a toner for developing electrostatic images that suppresses color streaks or color spots compared to when acidic water is not brought into contact with the toner particles. [Means for solving the problem]

[0005] The above problems are solved by the following means: <1> A first step of obtaining toner particles containing an amorphous polyester resin, a crystalline polyester resin, and a vinyl resin by a wet process; a second step of contacting the toner particles with acidic water. <2> The amount of Na on the surface of the toner particles before the second process (Na amount Befor ) the amount of Na on the toner particle surface after the second step (Na amount After ) is 0.10 mg / L or more and 2.0 mg / L or less, The amount of Na on the surface of the toner particles after the second step (Na amount After ) is between 0.05 mg / L and 0.4 mg / L <1> 10. A method for producing the toner for developing electrostatic images according to claim 9. <3> a third step of contacting the toner particles with washing water B after the second step, The amount of anions on the toner particle surface before the second process (anion amount Befor ) the amount of anions on the toner particle surface after the second step (anion amount After2 ) increase is 1 mg / L or more and 5 mg / L or less, The amount of anions on the surface of the toner particles after the third step (anion amount After3 ) is between 0.001 mg / L and 0.1 mg / L <1> or <2> 10. A method for producing the toner for developing electrostatic images according to claim 9. <4> The acidic water has an acid concentration of 0.5 mmol / L or more and 8 mmol / L or less. <1> ~ <3> 10. A method for producing the toner for developing electrostatic images according to any one of claims 1 to 9. <5> The temperature of the acidic water having an acid concentration of 0.5 mmol / L or more and 8 mmol / L or less is 35°C or less. <4> 10. A method for producing the toner for developing electrostatic images according to claim 9. <6> The acidic water is an aqueous nitric acid solution. <1> ~ <5> 10. A method for producing the toner for developing electrostatic images according to any one of claims 1 to 9. <7> before the second step, a step of bringing the toner particles into contact with washing water A is included. <1> ~ <6> 10. A method for producing the toner for developing electrostatic images according to any one of claims 1 to 9. <8> The mass of the cleaning water A is 150% by mass or more and 2000% by mass or less with respect to the total mass of the toner particles. <7> 10. A method for producing the toner for developing electrostatic images according to claim 9. <9> The mass of the crystalline polyester resin contained in the toner particles is 10% by mass or more and 30% by mass or less with respect to the mass of the entire toner particles. <1> ~ <8> 10. A method for producing the toner for developing electrostatic images according to any one of claims 1 to 9. [Effects of the Invention]

[0006] <1> According to the invention, there is provided a method for producing a toner for developing electrostatic images, which includes a step of obtaining toner particles containing an amorphous polyester resin, a crystalline polyester resin, and a vinyl resin by a wet process, and which produces a toner for developing electrostatic images that suppresses color streaks or color points compared to when acidic water is not brought into contact with the toner particles. <2> According to the invention, the amount of Na on the surface of the toner particles before the second step (Na amount Befor ) the amount of Na on the toner particle surface after the second step (Na amount After ) is less than 0.10 mg / L or exceeds 2.0 mg / L, or the amount of Na on the toner particle surface after the second step (Na amount After The present invention provides a method for producing a toner for developing electrostatic images that can suppress color streaks or color spots compared to when the concentration of the toner is less than 0.05 mg / L or more than 0.4 mg / L. <3> According to the invention, if the third step of bringing the toner particles into contact with washing water B after the second step is not included, the amount of anions on the toner particle surface before the second step (anion amount Befor ) the amount of anions on the toner particle surface after the second step (anion amount After2 ) is less than 1 mg / L or exceeds 5 mg / L, or the amount of anions on the toner particle surface after the third step (anion amount After3 The present invention provides a method for producing a toner for developing electrostatic images that can suppress color streaks or color spots compared to when the concentration of the toner is less than 0.001 mg / L or more than 0.1 mg / L. <4> According to the present invention, there is provided a method for producing a toner for developing electrostatic images, which can produce a toner for developing electrostatic images that suppresses color streaks or color spots compared to when the acid water has an acid concentration of less than 0.5 mmol / L or more than 8 mmol / L. <5> According to the present invention, there is provided a method for producing a toner for developing electrostatic images, which can produce a toner for developing electrostatic images that suppresses color streaks or color spots compared to when the temperature of acidic water having an acid concentration of 0.5 mmol / L or more and 8 mmol / L or less exceeds 35°C.

[0007] <6> According to the invention, there is provided a method for producing a toner for developing electrostatic images, which can produce a toner for developing electrostatic images that suppresses color streaks or color spots compared to when the acidic water is an aqueous sulfuric acid solution. <7> According to the invention, there is provided a method for producing a toner for developing electrostatic images, which can produce a toner for developing electrostatic images that suppresses color streaks or color spots compared to when cleaning water A is not brought into contact with the toner particles before the second step. <8> According to the invention, there is provided a method for producing a toner for developing electrostatic images, which can produce a toner for developing electrostatic images that suppresses color streaks or color spots, compared to when the mass of cleaning water A is less than 150 mass % or more than 2000 mass % of the total mass of the toner particles. <9> According to the invention, there is provided a method for producing a toner for developing electrostatic images, which can produce a toner for developing electrostatic images that suppresses color streaks or color spots compared to when the mass of the crystalline polyester resin contained in the toner particles is less than 10% by mass or more than 30% by mass relative to the mass of the entire toner particles. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment of the present invention will be described. These descriptions and examples are intended to illustrate the embodiment and are not intended to limit the scope of the invention. In the present specification, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range. In addition, in the present specification, the upper or lower limit of a numerical range may be replaced with a value shown in the examples.

[0009] Each component may contain multiple types of the corresponding substance. When referring to the amount of each component in a composition, if there are multiple substances corresponding to each component in the composition, the amount refers to the total amount of those multiple substances present in the composition, unless otherwise specified. In this specification, the term "process" includes not only an independent process but also a process that cannot be clearly distinguished from other processes, as long as the intended purpose of the process is achieved. Each component may contain multiple types of the corresponding substance.

[0010] <Method of manufacturing toner for developing electrostatic images> The method for producing the toner for developing electrostatic images according to this embodiment (hereinafter, "toner for developing electrostatic images" will also be referred to as "toner") includes a first step of obtaining toner particles containing an amorphous polyester resin, a crystalline polyester resin, and a vinyl resin by a wet process, and a second step of bringing acidic water into contact with the toner particles.

[0011] The toner manufacturing method according to the present embodiment, which has the above-described configuration, can obtain a toner that suppresses color streaks or color spots. The reason for this is presumed to be as follows.

[0012] When a toner containing an amorphous polyester resin and a crystalline polyester resin is produced by a wet process, the amount of sodium ions remaining on the toner particle surface tends to be large. In the wet process, alkalis, sodium salts, etc. may be added for the purpose of adjusting the pH, etc., and surfactants may be added to improve dispersion stability, and the sodium ions remaining on the toner particle surface are thought to be derived from the alkalis, sodium salts, surfactants, etc. The surfaces of toner particles containing amorphous polyester resin and crystalline polyester resin contain carboxyl groups (-COOH) contained in the amorphous polyester resin and crystalline polyester resin. It is believed that the hydrogen atoms contained in these carboxyl groups are replaced with sodium ions during the production of the toner particles, resulting in sodium ions remaining on the toner particle surfaces. In addition, when a surfactant containing sodium ions is used, it is believed that the surfactant adsorbs to the toner particle surfaces, resulting in sodium ions remaining on the toner particle surfaces. In the production of toner particles containing an amorphous polyester resin and a crystalline polyester resin, the amorphous polyester resin and the crystalline polyester resin have high affinity and tend to form amorphous regions. The amorphous regions tend to incorporate surfactants, which tend to be adsorbed onto the toner particle surfaces. Since the surfactants incorporated into the amorphous regions are difficult to remove, when a toner containing an amorphous polyester resin and a crystalline polyester resin is produced by a wet process, the amount of sodium ions remaining on the toner particle surfaces tends to be large. Furthermore, when an image is formed using toner particles with a high amount of sodium ions on the surface, image defects such as color streaks (i.e., unintended linear images) or color dots (i.e., unintended dot-like images) are likely to occur.

[0013] The toner manufacturing method according to this embodiment includes a first step of obtaining toner particles containing an amorphous polyester resin, a crystalline polyester resin, and a vinyl resin by a wet process. The vinyl resin has low affinity with the amorphous polyester resin and the crystalline polyester resin. Therefore, during the production of toner particles, the vinyl resin is prone to phase separation in the binder resin. When the vinyl resin causes phase separation, segmental motion occurs in the crystalline polyester resin, which facilitates crystallization of the crystalline polyester resin. This makes it difficult for the above-mentioned amorphous regions to form, and makes it difficult for surfactants to adsorb to the toner particle surfaces. The toner manufacturing method according to this embodiment also includes a second step of bringing acidic water into contact with the toner particles. By bringing acidic water into contact with the toner particles, sodium ions can be replaced with protons by ion exchange. As a result, the toner manufacturing method according to this embodiment tends to reduce the amount of sodium ions remaining on the toner particle surface, thereby obtaining a toner that suppresses color streaks or color spots.

[0014] From the above, it is presumed that the toner manufacturing method according to this embodiment can produce a toner that suppresses color streaks or color points.

[0015] (1st step) The first step is a step of obtaining toner particles containing an amorphous polyester resin, a crystalline polyester resin, and a vinyl resin by a wet process. Examples of the wet production method include an aggregation-coalescence method, a suspension polymerization method, and a dissolution-suspension method. Among these, it is preferable to obtain toner particles by the aggregation and coalescence method. Hereinafter, a method for producing toner particles by the aggregation-coalescence method will be described as an example of the wet production method.

[0016] For example, when toner particles are produced by the aggregation and coalescence method, It is preferable to manufacture toner particles through the following steps: a step of preparing a resin particle dispersion in which resin particles to be a binder resin are dispersed (resin particle dispersion preparation step); a step of aggregating the resin particles (and other particles, as needed) in the resin particle dispersion (in a dispersion after mixing other particle dispersions, as needed) to form aggregated particles (aggregated particle formation step); and a step of heating the aggregated particle dispersion in which the aggregated particles are dispersed to fuse and coalesce the aggregated particles to form toner particles (fusion and coalescence step).

[0017] Each step will be described in detail below. In the following description, a method for obtaining toner particles containing a colorant and a release agent will be described, but the colorant and the release agent are used as needed. Of course, additives other than the colorant and the release agent may also be used.

[0018] -Resin particle dispersion preparation process- The resin particle dispersion preparation step is a step of preparing a resin particle dispersion in which resin particles that will become a binder resin are dispersed. In addition, in the resin particle dispersion liquid preparation step, for example, a colorant particle dispersion liquid in which colorant particles are dispersed and a release agent particle dispersion liquid in which release agent particles are dispersed are also prepared.

[0019] ·Resin particle dispersion The resin particle dispersion contains resin particles and a dispersion medium, and may contain a surfactant as needed.

[0020] It is preferable that the resin particles be prepared separately from each other: resin particles containing an amorphous polyester resin, resin particles containing a crystalline polyester resin, and resin particles containing a vinyl resin. That is, it is preferable to separately prepare a resin particle dispersion liquid in which resin particles containing an amorphous polyester resin are dispersed, a resin particle dispersion liquid in which resin particles containing a crystalline polyester resin are dispersed, and a resin particle dispersion liquid in which resin particles containing a vinyl resin are dispersed.

[0021] The amorphous polyester resin, crystalline polyester resin, and vinyl resin contained in the resin particle dispersion liquid have the same meanings as the amorphous polyester resin, crystalline polyester resin, and vinyl resin in the description of the binder resin contained in the toner particles described later, and the preferred ranges are also the same.

[0022] The volume average particle size of the resin particles is, for example, preferably 0.01 μm or more and 1 μm or less, more preferably 0.04 μm or more and 0.8 μm or less, and even more preferably 0.06 μm or more and 0.6 μm or less. The volume average particle size of the resin particles is measured using a particle size distribution obtained by measurement with a laser diffraction particle size distribution analyzer (e.g., LA-700 manufactured by Horiba, Ltd.), and the cumulative distribution for the volume of the divided particle size range (channel) is subtracted from the small particle size side, and the particle size at which the cumulative 50% of all particles is measured is defined as the volume average particle size D50v. The volume average particle sizes of particles in other dispersions are also measured in the same way.

[0023] Examples of the dispersion medium used in the resin particle dispersion include aqueous media. Examples of aqueous media include water such as distilled water and ion-exchanged water, alcohols, etc. These may be used alone or in combination of two or more.

[0024] Examples of surfactants include anionic surfactants such as sulfate ester salts, sulfonate salts, phosphate esters, and soaps; cationic surfactants such as amine salts and quaternary ammonium salts; and nonionic surfactants such as polyethylene glycols, alkylphenol ethylene oxide adducts, and polyhydric alcohols. Among these, anionic surfactants and cationic surfactants are particularly preferred. Nonionic surfactants may be used in combination with anionic surfactants or cationic surfactants. The surfactants may be used alone or in combination of two or more.

[0025] The content of resin particles contained in the resin particle dispersion is, for example, preferably from 5% by mass to 50% by mass, and more preferably from 10% by mass to 40% by mass.

[0026] Examples of methods for preparing a resin particle dispersion include dispersing a solution containing resin particles and a dispersion medium using a rotary shear homogenizer, a ball mill with media, a sand mill, a dyno mill, or the like. The resin particle dispersion may be prepared, for example, by dispersing resin particles in a resin particle dispersion using a phase inversion emulsification method. The phase inversion emulsification method involves dissolving the resin to be dispersed in a hydrophobic organic solvent in which the resin is soluble, adding a base to the organic continuous phase (O phase) to neutralize it, and then adding an aqueous medium (W phase), thereby converting the resin from W / O to O / W (so-called phase inversion) and forming a discontinuous phase, and dispersing the resin in particulate form in the aqueous medium.

[0027] Colorant particle dispersion The colorant particle dispersion contains particles containing a colorant and a dispersion medium, and may contain a surfactant as needed. The colorant contained in the colorant particle dispersion liquid is synonymous with the colorant contained in the toner particles described below, and the same colorant as the colorant contained in the toner particles is used. The dispersion medium and surfactant contained in the colorant particle dispersion liquid may be the same as those contained in the resin particle dispersion liquid described above.

[0028] Examples of methods for preparing a colorant particle dispersion include dispersing a solution containing a colorant, a dispersion medium, and a surfactant using a rotary shear homogenizer, a ball mill with media, a sand mill, a dyno mill, or the like.

[0029] Release agent particle dispersion The release agent particle dispersion contains particles containing a release agent and a dispersion medium, and may contain a surfactant as needed. The release agent contained in the release agent particle dispersion liquid is synonymous with the release agent contained in the toner particles described below, and the same release agent as that contained in the toner particles is used. The dispersion medium and surfactant contained in the release agent particle dispersion liquid may be the same as those contained in the resin particle dispersion liquid described above.

[0030] Examples of methods for preparing the release agent particle dispersion include a method in which a solution containing a release agent, a dispersion medium, and a surfactant is heated to melt the release agent, and then the resulting mixture is dispersed using a rotary shear homogenizer, a ball mill having media, a sand mill, a dyno mill, or the like.

[0031] -Agglomerated particle formation process- A colorant particle dispersion and a release agent particle dispersion are mixed with the resin particle dispersion to obtain a mixed dispersion. Then, in the mixed dispersion, the resin particles, colorant particles, and release agent particles are hetero-aggregated to form aggregated particles containing the resin particles, colorant particles, and release agent particles and having a diameter close to that of the target toner particles.

[0032] Specifically, for example, an aggregating agent is added to the mixed dispersion, and the pH of the mixed dispersion is adjusted to be acidic (for example, a pH of 2 or more and 5 or less), and a dispersion stabilizer is added as necessary. After that, the mixed dispersion is heated to the glass transition temperature of the resin particles (specifically, for example, a temperature of the glass transition temperature of the resin particles -30°C or more and the glass transition temperature -10°C or less), and the particles dispersed in the mixed dispersion are aggregated to form aggregated particles. In the aggregate particle formation step, for example, the mixed dispersion may be stirred with a rotary shear homogenizer, an aggregating agent may be added at room temperature (e.g., 25°C), the pH of the mixed dispersion may be adjusted to an acidic value (e.g., a pH of 2 or more and 5 or less), a dispersion stabilizer may be added as needed, and then the above-mentioned heating may be carried out.

[0033] Examples of the flocculant include a surfactant having a polarity opposite to that of the surfactant used as the dispersant added to the mixed dispersion, an inorganic metal salt, a divalent or higher metal complex, etc. In particular, when a metal complex is used as the flocculant, the amount of surfactant used can be reduced and the charging characteristics can be improved. If necessary, an additive that forms a complex or a similar bond with the metal ions of the flocculant may be used, and a chelating agent is preferably used as this additive.

[0034] Examples of inorganic metal salts include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate; and inorganic metal salt polymers such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. The chelating agent may be a water-soluble chelating agent, such as hydroxycarboxylic acid (e.g., tartaric acid, citric acid, gluconic acid), iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA), etc. The amount of the chelating agent added is, for example, preferably 0.01 parts by mass or more and 5.0 parts by mass or less, and more preferably 0.1 parts by mass or more and less than 3.0 parts by mass, per 100 parts by mass of the resin particles.

[0035] -Fusion / unification process- Next, the aggregated particle dispersion liquid in which the aggregated particles are dispersed is heated, for example, to a temperature equal to or higher than the glass transition temperature of the resin particles (for example, a temperature 10 to 30°C higher than the glass transition temperature of the resin particles), to fuse and coalesce the aggregated particles and form toner particles.

[0036] (2nd process) The second step is a step of bringing the toner particles into contact with acidic water. Acidic water is an aqueous solution containing an acid.

[0037] From the viewpoint of further reducing the amount of sodium ions remaining on the toner particle surface, the pKa of the acid in water at 25°C is preferably -10 or more and 4.5 or less, more preferably -10 or more and 2 or less, and even more preferably -10 or more and 0 or less.

[0038] The acid is preferably a monovalent acid. A monovalent acid is an acid that can dissociate into one proton and a monovalent counter anion in an aqueous solution. When acidic water is brought into contact with toner particles, counter anions may remain on the toner particle surface. When counter anions remain on the toner particle surface, the toner particles are more likely to absorb moisture from the air. When toner particles absorb moisture, the toner particle surface becomes soft. For example, when low-density images are continuously formed in a high-temperature, high-humidity environment, external additives are more likely to be embedded in the toner particle surface, making toner particles more likely to adhere to each other. When toner particles adhere to each other, image defects such as color streaks or color spots are more likely to occur. The higher the valence of the counter anion, the more likely the toner particles are to absorb moisture from the air when counter anions remain on the toner particle surface. Therefore, using a monovalent acid as the acid makes it more difficult for toner particles to absorb moisture from the air compared to using a divalent or higher acid. This suppresses image defects such as color streaks or color spots.

[0039] The acid may be an inorganic acid or an organic acid. Inorganic acids are acids that do not contain carbon atoms, while organic acids are acids that do contain carbon atoms. Examples of inorganic acids include hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, hydroiodic acid, hydrobromic acid, chloric acid, bromic acid, iodic acid, permanganic acid, thiocyanic acid, perchloric acid, perbromic acid, tetrafluoroboric acid, and hexafluorophosphoric acid. From the viewpoint of making it difficult for the toner particles to absorb moisture in the air, the inorganic acid is preferably at least one selected from the group consisting of hydrochloric acid, sulfuric acid, and nitric acid.

[0040] Examples of the organic acid include citric acid, acetic acid, benzoic acid, salicylic acid, and p-toluenesulfonic acid.

[0041] The acid is more preferably nitric acid. That is, the acidic water is preferably an aqueous solution of nitric acid. Nitric acid is a monovalent acid, so if the counter anion remains on the toner particle surface, the toner particles will be less likely to absorb moisture from the air. Nitric acid also has a greater tendency to ionize than other anions, which is thought to facilitate efficient ion exchange in water. This makes it easier to obtain a toner that suppresses color streaks or color spots.

[0042] The acidic water preferably has an acid concentration (the number of moles of acid contained in 1 L of acidic water) of 0.5 mmol / L or more and 8 mmol / L or less. By setting the acid concentration to 0.5 mmol / L or more, when the toner particles are brought into contact with acidic water, it is possible to more efficiently exchange the sodium ions remaining on the toner particle surfaces with protons. Furthermore, by setting the acid concentration to 8 mmol / L or less, the amount of counter anions derived from the acid remaining on the surface of the toner particles tends to be reduced.

[0043] From the viewpoint of more easily obtaining a toner that suppresses color streaks or color spots, the acid concentration of the acidic water is more preferably 1.0 mmol / L or more and 6 mmol / L or less, and even more preferably 1.5 mmol / L or more and 4 mmol / L or less.

[0044] The temperature of acidic water having an acid concentration of 0.5 mmol / L or more and 8 mmol / L or less (hereinafter also referred to as specific acidic water) is preferably 35°C or less. From the viewpoint of increasing the efficiency of ion exchange, it is preferable that the amount of protons released from the acid is large. In order to increase the amount of protons released from the acid, it is preferable that the temperature of the acidic water is high. However, if the temperature of the acidic water is too high, when the acidic water is brought into contact with the toner particles, the toner particles are likely to fuse together, and coarse particles are likely to be generated. By setting the upper limit of the temperature of the specific acidic water to 35°C, the efficiency of ion exchange is increased, and the fusion of toner particles when the specific acidic water is brought into contact with the toner particles is suppressed.

[0045] From the viewpoint of increasing the efficiency of ion exchange while suppressing fusion of toner particles when brought into contact with the toner particles, the temperature of the specific acidic water is preferably 15°C or higher and 35°C or lower, more preferably 20°C or higher and 33°C or lower, and even more preferably 25°C or higher and 31°C or lower.

[0046] The temperature of the acidic water is measured with a contact thermometer. As a contact thermometer, for example, a product called Thermowell (PFA coating) manufactured by Okazaki Seisakusho Co., Ltd. can be used.

[0047] The amount of Na on the toner particle surface before the second process (Na amount Befor ) the amount of Na on the toner particle surface after the second step (Na amount After ) is 0.10 mg / L or more and 2.0 mg / L or less, and the amount of Na on the toner particle surface after the second process (Na amount After ) is preferably 0.05 mg / L or more and 0.4 mg / L or less.

[0048] The amount of Na on the surface of the toner particles after the second process (Na amount After ) is 0.05 mg / L or more, the amount of sodium ions remaining on the toner particle surface is not too small. Therefore, the toner particle surface is prevented from being made too hydrophobic, and the surface hardness of the crystalline portion present on the toner particle surface is unlikely to become relatively hard. Therefore, for example, when an image with low image density is formed under low temperature and low humidity conditions, the external additive is unlikely to be unevenly distributed in areas other than the crystalline portion on the toner particle surface. This makes it difficult for toner particles to aggregate with each other, making it easier to obtain a toner that suppresses color streaks or color spots. In addition, the amount of Na (Na amount) on the toner particle surface after the second process is After By making the concentration of sodium ions 0.4 mg / L or less, the amount of sodium ions remaining on the toner particle surface is reduced, and a toner that suppresses color streaks or color spots can be obtained. In addition, the amount of Na on the surface of the toner particles before the second process (Na amount Befor ) the amount of Na on the toner particle surface after the second step (Na amount AfterBy keeping the decrease in the concentration of the toner particles at 2.0 mg / L or less, the amount of acidic water used in the second step is not too large. This allows an adequate amount of surfactant adsorbed to the toner particle surface to remain, allowing the toner particles to repel each other to an adequate degree. This makes it difficult for the toner particles to aggregate, suppressing the generation of coarse particles. Furthermore, the amount of Na on the surface of the toner particles before the second process (Na amount Befor ) the amount of Na on the toner particle surface after the second step (Na amount After By making the decrease amount of ) 0.10 mg / L or more, for example, the amount of Na on the surface of the toner particles before the second process (Na amount Befor ) is 0.5 mg / L or more, the amount of Na on the toner particle surface after the second process (Na amount After ) is likely to be in the range of 0.05 mg / L or more and 0.4 mg / L or less.

[0049] In order to further suppress the generation of coarse particles, the amount of Na Befor Amount of Na from After The amount of decrease is more preferably 0.50 mg / L or more and 1.8 mg / L or less, and even more preferably 0.80 mg / L or more and 1.5 mg / L or less.

[0050] From the viewpoint of obtaining a toner that suppresses color streaks or color spots, the amount of Na After is more preferably 0.08 mg / L or more and 0.38 mg / L or less, and further preferably 0.10 mg / L or more and 0.35 mg / L or less.

[0051] Below is the amount of Na Befor The measurement procedure will be explained. Na content Befor The measurement procedure is as follows: (1) Preparation of a calibration curve, and (2) Measurement of the amount of Na using the calibration curve. Befor This is done by calculating:

[0052] (1) Preparation of a calibration curve The calibration curve is created by "collecting a measurement sample," "measuring the amount of Na on the surface of the toner particles," "measuring the electrical conductivity of the filtrate," and "plotting the data." Collection of measurement samples A portion of the toner particle dispersion before the second process (100 g of toner particles) is placed into a stainless steel holder with a tank (Advantec KST-90, hereafter simply referred to as the device) equipped with filter paper so that 100 g of toner particles are contained within the device, and then pressure-filtered at 0.4 MPa. When no more filtrate comes out, the pressure filtration is stopped, a cake (also referred to as the initial cake) is obtained, and the filtrate is recovered (the recovered filtrate is referred to as filtrate 1). 1 g of toner particles is sampled from the cake, being careful not to break it, and dried under exhaust air. The resulting dried toner particles are referred to as toner particles A. Next, ion-exchanged water in an amount of 100% by mass relative to the remaining toner mass (i.e., the mass of the cake (g) - 1 g) was added to the device, and pressure filtration was performed at 0.4 MPa, and the filtrate was recovered (the recovered filtrate is referred to as filtrate 2). When no more filtrate was produced, pressure filtration was stopped, and 1 g of toner particles was sampled without breaking the cake, and dried with exhaust air. The resulting dried toner particles are referred to as toner particles B. The same operation is repeated to collect toner particles (specifically, toner particles A, toner particles B, hereinafter referred to as consecutive numbers in the order of collection) and filtrate (specifically, filtrate 1, filtrate 2, hereinafter referred to as consecutive numbers in the order of collection) until the total amount of ion-exchanged water added reaches 2000% by mass relative to the initial cake mass.

[0053] Measurement of the amount of sodium on the surface of toner particles The amount of Na on the surface of the sampled toner particles (that is, toner particles A, toner particles B, hereinafter consecutive numbers) is measured by ion chromatography. 0.5 g of the sampled toner particles are weighed and dispersed in 100 g of ion-exchanged water to which 0.1 g of a nonionic surfactant (Nonipol 10 manufactured by Sanyo Chemical Industries, Ltd.), equivalent to 20% of the toner particles, has been added, and the mixture is dispersed for 30 minutes using an ultrasonic disperser in a thermostatic chamber controlled at 30±1°C. The liquid after ultrasonic dispersion is subjected to solid-liquid separation by suction filtration to remove solid toner particles, and the obtained filtrate is used as a measurement sample. Note that measurement samples are prepared for each toner particle sample. A blank sample is also prepared without adding any toner particles. Next, the amount of Na contained in the measurement sample and the blank sample is measured by ion chromatography using an ICS-2000 manufactured by Nippon Dionex Co., Ltd., under the following conditions: Cation separation column: Nippon Dionex, IonPacCS12A Cation guard column: Nippon Dionex, IonPacCG12A Eluent: methanesulfonic acid 20mM (mmol / L) ·Flow rate: 1mL / min ·Temperature: 35℃ Detection method: Electrical conductivity method (suppressor type) The amount of Na (mg / L) on the surface of the toner particles is calculated from the amount of Na obtained by the above measurement. The amount of Na (mg / L) on the surface of the toner particles is calculated by subtracting the amount of Na (mg / L) of the blank sample from the amount of Na (mg / L) of the measurement sample.

[0054] Measurement of the electrical conductivity of the filtrate The electrical conductivity (S / m) of each of the collected filtrates (specifically, filtrate 1, filtrate 2, and so on) is measured.

[0055] Data plotting The measured electrical conductivity of the filtrate and the amount of Na on the toner particle surface are plotted on a graph with electrical conductivity (S / m) on the x-axis and the amount of Na on the toner particle surface (mg / L) on the y-axis. Specifically, (x, y) = (electrical conductivity of filtrate 1, amount of Na on the surface of toner particle A), (electrical conductivity of filtrate 2, amount of Na on the surface of toner particle B), and so on. An approximate line is drawn using the least squares method based on the plotted points, and this is used as the calibration curve.

[0056] (2) Na content according to the calibration curve Befor Calculation of In step 1.5 described later, the toner particles are brought into contact with the washing water A, and then filtered. 50 ml of the filtrate is collected immediately before the completion of the filtration. The electrical conductivity of this filtrate is measured, and the amount of Na is calculated from the measured value and the prepared calibration curve. Befor Calculate. The calibration curve should be created again if the amount of raw material added is changed.

[0057] Next, the amount of Na After The measurement procedure will be explained. Na content After The measurement procedure is as follows: (1) Preparation of a calibration curve, and (2) Measurement of the amount of Na using the calibration curve. After This is done by calculating:

[0058] (1) Preparation of a calibration curve The calibration curve is created by "collecting a measurement sample," "measuring the amount of Na on the surface of the toner particles," "measuring the electrical conductivity of the filtrate," and "plotting the data." Collection of measurement samples Na content Befor The same procedure as in "(1) Preparation of the calibration curve and collection of the measurement sample" in the measurement procedure is carried out four times using different devices, and a total of four devices containing cakes are prepared. In one of the devices containing the cake, ion-exchanged water in an amount of 200% by mass relative to the mass of the cake is added and filtered under pressure. This device is designated as Device A. In addition, ion-exchanged water in an amount of 300% by mass relative to the mass of the cake was added to another apparatus containing the cake, and pressure filtration was performed. This apparatus was designated as apparatus B. Furthermore, ion-exchanged water in an amount of 600% by mass relative to the mass of the cake was added to another apparatus containing the cake, and pressure filtration was performed. This apparatus was designated as apparatus C. The remaining cake is not charged with ion-exchanged water. This device is called Device D. Then, the following operations are carried out in each of the devices A to D. 100% by mass of the acidic water used in step 2 (the type of acid contained in the acidic water, the acid concentration of the acidic water, and the temperature of the acidic water were the same as those of the acidic water used in step 2) was added to the apparatus relative to the mass of the cake contained in the apparatus (this cake is also referred to as initial cake 2), and the apparatus was subjected to pressure filtration at 0.4 MPa, and the filtrate was collected (the collected filtrate is referred to as filtrate 2-1). When no more filtrate was produced, the pressure filtration was stopped, and 1 g of toner particles was sampled without breaking the cake, and dried by exhaust air. The resulting dried toner particles are referred to as toner particles 2-A. The same operation is repeated to collect toner particles (specifically, toner particles 2-A, toner particles 2-B, hereinafter referred to as consecutive numbers in the order of collection) and filtrate (specifically, filtrate 2-1, filtrate 2-2, hereinafter referred to as consecutive numbers in the order of collection), while adding acidic water to the apparatus in an amount of 2000% by mass in total relative to the mass of the initial cake 2, and filtering under pressure.

[0059] Measurement of the amount of sodium on the surface of toner particles The amount of Na (mg / L) on the surface of the sampled toner particles (i.e., toner particles 2-A, toner particles 2-B, hereinafter consecutive numbers) is measured. Befor Measurement procedure (1) Preparation of calibration curve The method is the same as that described in "Measurement of the amount of Na on the surface of toner particles."

[0060] Measurement of the electrical conductivity of the filtrate The electrical conductivity (S / m) of each of the collected filtrates (specifically, filtrate 2-1, filtrate 2-2, and so on) is measured. The measurement method is "Na content Befor Measurement procedure (1) Preparation of calibration curve: The same method as described in "Measurement of electrical conductivity of filtrate."

[0061] Data plotting The measured electrical conductivity of the filtrate and the amount of Na on the toner particle surface are plotted on a graph with electrical conductivity (S / m) on the x-axis and the amount of Na on the toner particle surface (mg / L) on the y-axis. Specifically, (x, y) = (electrical conductivity of filtrate 2-1, amount of Na on the surface of toner particle 2-A), (electrical conductivity of filtrate 2-2, amount of Na on the surface of toner particle 2-B), and so on. An approximate line is drawn using the least squares method based on the plotted points, and this is used as the calibration curve.

[0062] Through the above procedure, a total of four calibration curves calculated using each of the devices A to D are obtained. In addition, if the amount of raw material added or the acid concentration changes, the calibration curve is prepared again at the specified acid concentration. Also, if the acid temperature changes, the calibration curve is prepared again.

[0063] (2) Na content according to the calibration curve After Calculation of In the second step, the toner particles are brought into contact with acidic water, and then filtered. 50 ml of the filtrate is collected immediately before the completion of the filtration. The electrical conductivity of this filtrate is measured, and the amount of Na is calculated from the measured value and the prepared calibration curve. After Calculate.

[0064] In addition, the amount of Na After The calibration curve used for the calculation is selected as follows: Select the calibration curve obtained using the device in which the amount (mass %) of ion-exchanged water relative to the mass of the cake added to the device when preparing devices A to D is closest to the amount (mass %) of washing water A relative to the mass of the entire toner particles added in step 1.5 described below. Specifically, when washing water A is added in an amount of 600% by mass relative to the total mass of the toner particles in step 1.5 described below, the calibration curve calculated using apparatus C is selected.

[0065] The method for bringing the toner particles into contact with the acidic water is not particularly limited. For example, there is a method in which acidic water is added to toner particles to form a slurry, and the slurry is stirred (reslurry method). Another method is to add toner particles to the filter chamber of a filter press and squeeze them to form a cake layer of toner particles, and then pass acidic water through the cake layer (filter press method). From the viewpoint of further reducing the amount of sodium ions remaining on the toner particle surface, the method of bringing the toner particles into contact with acidic water is preferably a filter press method. The filter press may be a horizontal filter press (a filter press that applies force in the horizontal direction to compress) or a vertical filter press (a filter press that applies force in the direction perpendicular to the horizontal direction to compress).

[0066] (Step 1.5) It is preferable to include a step of bringing the toner particles into contact with washing water A (hereinafter also referred to as "step 1.5") before the second step.

[0067] By contacting the toner particles with cleaning water A before the second step, the amount of sodium ions on the toner particle surface before contact with acidic water is reduced compared to when cleaning water A is not contacted. Therefore, the amount of acidic water used in the second step is not too large. As a result, an appropriate amount of surfactant adsorbed to the toner particle surface remains, and toner particles repel each other appropriately. This makes it difficult for toner particles to aggregate, and the generation of coarse particles is suppressed. When the generation of coarse particles is suppressed, the occurrence of image defects such as color streaks or color spots is suppressed.

[0068] The washing water A is preferably water. The water is not particularly limited, and ion-exchanged water, ultrapure water, distilled water, ultrafiltered water, etc. may be used. However, from the viewpoint of reducing the amount of ions remaining on the surface of the toner particles, it is preferable to use at least one of ion-exchanged water and ultrapure water.

[0069] The mass of the cleaning water A is preferably 150% by mass or more and 2000% by mass or less, more preferably 200% by mass or more and 1500% by mass or less, and even more preferably 250% by mass or more and 1000% by mass or less, relative to the mass of the entire toner particles.

[0070] By setting the mass of the washing water A to 150% by mass or more relative to the mass of the entire toner particles, the amount of sodium ions on the surfaces of the toner particles before contact with the acidic water tends to be reduced. There is no particular upper limit to the mass of the washing water A relative to the mass of the entire toner particles, but from the viewpoint of shortening the time for step 1.5, it is preferably 2000% by mass or less.

[0071] The method for bringing the washing water A into contact with the toner particles is not particularly limited, but for example, there is a method in which the washing water A is added to the toner particles to form a slurry, and the slurry is stirred (reslurry method). Another method is to add toner particles to the filter chamber of a filter press and squeeze them to form a cake layer of toner particles, and then pass washing water A over the cake layer (filter press method).

[0072] (3rd step) It is preferable to include a third step of bringing washing water B into contact with the toner particles after the second step. Here, the cleaning water B is preferably water. Specific examples and preferred ranges of water are the same as those of cleaning water A.

[0073] As mentioned above, if a large amount of counter anions derived from the acid contained in the acidic water added in the second step remain on the surface of the toner particles, the toner particles will be more likely to absorb moisture from the air, which will cause the toner particles to adhere to each other, resulting in image defects such as color streaks or color spots. By including the third step, the amount of counter anions remaining on the toner particle surface can be reduced, and image defects such as color streaks or color spots can be further suppressed.

[0074] From the viewpoint of obtaining a toner that further suppresses image defects such as color streaks or color spots, the mass of the cleaning water B is preferably 100% by mass or more and 2000% by mass or less, more preferably 200% by mass or more and 1500% by mass or less, and even more preferably 300% by mass or more and 1000% by mass or less, relative to the mass of the total toner particles.

[0075] The method of bringing the cleaning water B into contact with the toner particles can be the same as the method of bringing the cleaning water A into contact with the toner particles described above.

[0076] After the second step, a third step of contacting the toner particles with washing water B is included, and the amount of anions on the toner particle surfaces before the second step (anion amount Befor ) the amount of anions on the toner particle surface after the second step (anion amount After2 ) is 1 mg / L or more and 5 mg / L or less, and the amount of anions on the toner particle surface after the third step (anion amount After3 ) is preferably 0.001 mg / L or more and 0.1 mg / L or less.

[0077] Anion Amount Befor Amount of anions from After2 By setting the increase in the concentration of the acid-derived counter anions to 1 mg / L or more and 5 mg / L or less, the amount of acid-derived counter anions remaining on the toner particle surface is prevented from becoming too large. Therefore, by contacting the toner with washing water B in the third step, the amount of acid-derived counter anions remaining on the toner particle surface is more likely to be reduced. As a result, image defects such as color streaks or color spots are more likely to occur. In addition, the amount of anions After3 By adjusting the concentration to 0.001 mg / L or more and 0.1 mg / L or less, the amount of counter anions derived from the acid remaining on the toner particle surface is reduced, and a toner that suppresses color streaks or color spots can be obtained.

[0078] Anion Amount Befor Amount of anions from After2 The increase is more preferably 1 mg / L or more and 3 mg / L or less, and even more preferably 1 mg / L or more and 2 mg / L or less.

[0079] Anion Amount After3 is more preferably 0.01 mg / L or more and 0.08 mg / L or less, and even more preferably 0.02 mg / L or more and 0.05 mg / L or less.

[0080] The anion amount is as follows: Befor The measurement procedure will be explained. Anion Amount Befor The measurement procedure is as follows: (1) Preparation of a calibration curve, and (2) Measurement of the amount of anions using the calibration curve. Befor This is done by calculating:

[0081] (1) Preparation of a calibration curve The calibration curve is created by "collecting a measurement sample," "measuring the amount of anions on the surface of the toner particles," "measuring the electrical conductivity of the filtrate," and "plotting the data."

[0082] Collection of measurement samples Na content Befor Perform the same operations as in "(1) Preparation of calibration curve and collection of measurement sample" in the measurement procedure.

[0083] Measurement of the amount of anions on the surface of toner particles The measurement conditions for the ion chromatography method were changed as follows, and the measurement target was changed from "Na content" to "anion content (specifically, the total amount of nitrate ions, sulfate ions, chloride ions, and nitrite ions. The same applies hereinafter.)" Befor The same operation as in "(1) Preparation of calibration curve - Measurement of the amount of Na on the surface of toner particles" in the measurement procedure is carried out. Anion separation column: Thermo Scientific, Dionex IonPac AS18 Anion guard column: Thermo Scientific, Dionex IonPac ATC-HC600 Eluent: Potassium hydroxide aqueous solution 40 mM (mmol / L) ·Flow rate: 1mL / min ·Temperature: 35℃ Detection method: Electrical conductivity method (suppressor type)

[0084] Measurement of the electrical conductivity of the filtrate Na content Befor Perform the same procedure as in "(1) Preparation of calibration curve - Measurement of electrical conductivity of filtrate" in the measurement procedure.

[0085] Data plotting The measured electrical conductivity of the filtrate and the amount of anions on the toner particle surface are plotted on a graph with electrical conductivity (S / m) on the x-axis and the amount of anions on the toner particle surface (mg / L) on the y-axis. Specifically, (x, y) = (electrical conductivity of filtrate 1, amount of anions on the surface of toner particle A), (electrical conductivity of filtrate 2, amount of anions on the surface of toner particle B), and so on. An approximate line is drawn using the least squares method based on the plotted points, and this is used as the calibration curve.

[0086] (2) Anion amount based on calibration curve Befor Calculation of In step 1.5 described later, the toner particles are brought into contact with the washing water A, and then filtered. 50 ml of the filtrate is collected immediately before the completion of the filtration. The electrical conductivity of this filtrate is measured, and the amount of anions is calculated from the measured value and the prepared calibration curve. Befor Calculate.

[0087] Next, the amount of anions After2 The measurement procedure will be explained. Anion Amount After The measurement procedure is as follows: (1) Preparation of a calibration curve, and (2) Measurement of the amount of anions using the calibration curve. After This is done by calculating:

[0088] (1) Preparation of a calibration curve The calibration curve is created by "collecting a measurement sample," "measuring the amount of anions on the surface of the toner particles," "measuring the electrical conductivity of the filtrate," and "plotting the data." Collection of measurement samples Na content After Perform the same operations as in "(1) Preparation of calibration curve and collection of measurement sample" in the measurement procedure.

[0089] Measurement of the amount of anions on the surface of toner particles The measurement conditions for ion chromatography were set as follows: Befor The conditions were changed to be the same as those in "(1) Preparation of a calibration curve - Measurement of the amount of anions on the surface of toner particles" in the measurement procedure, except that the measurement target was changed from "amount of Na" to "amount of anions." After The same operation as in "(1) Preparation of calibration curve - Measurement of the amount of Na on the surface of toner particles" in the measurement procedure is carried out.

[0090] Measurement of the electrical conductivity of the filtrate Na content After Perform the same procedure as in "(1) Preparation of calibration curve - Measurement of electrical conductivity of filtrate" in the measurement procedure.

[0091] Data plotting The measured electrical conductivity of the filtrate and the amount of anions on the toner particle surface are plotted on a graph with electrical conductivity (S / m) on the x-axis and the amount of anions on the toner particle surface (mg / L) on the y-axis. Specifically, (x, y) = (electrical conductivity of filtrate 2-1, amount of anions on the surface of toner particle 2-A), (electrical conductivity of filtrate 2-2, amount of anions on the surface of toner particle 2-B), and so on. An approximate line is drawn using the least squares method based on the plotted points, and this is used as the calibration curve.

[0092] (2) Anion amount based on calibration curve After Calculation of In the second step, the toner particles are brought into contact with acidic water, and then filtered. 50 ml of the filtrate is collected immediately before the completion of the filtration. The conductivity of this filtrate is measured, and the amount of anion is calculated from the measured value and the prepared calibration curve. After Calculate.

[0093] In addition, the amount of anions After The selection of the calibration curve to be used for the calculation is based on "(2) Na content by calibration curve" After The calculation of the

[0094] Next, the amount of anions After3 The measurement procedure will be explained. The amount of anions on the surface of the toner particles after the third step is measured by ion chromatography. 0.5 g of the toner particles after the third step are weighed and dispersed in 100 g of ion-exchanged water to which 0.1 g of a nonionic surfactant (Nonipol 10 manufactured by Sanyo Chemical Industries, Ltd.), equivalent to 20% of the toner particles, has been added, and the mixture is dispersed for 30 minutes using an ultrasonic disperser in a thermostatic chamber controlled at 30±1°C. The liquid after ultrasonic dispersion is subjected to solid-liquid separation by suction filtration to remove solid toner particles, and the resulting filtrate is used as a measurement sample. A blank sample is also prepared without adding any toner particles. Subsequently, the amount of anions contained in the measurement sample and the blank sample is measured by ion chromatography. For the ion chromatography, an ICS-2000 manufactured by Nippon Dionex Co., Ltd. is used, and the measurement conditions are as follows: Befor The conditions are the same as those in "(1) Preparation of a calibration curve - Measurement of the amount of anions on the surface of toner particles" in the measurement procedure. From the amount of anions obtained by the above measurement, the amount of anions After3 Calculate (mg / L). Anion Amount After3 The anion concentration (mg / L) is calculated by subtracting the anion concentration (mg / L) of the blank sample from the anion concentration (mg / L) of the measurement sample.

[0095] (Other processes) The method for producing the toner according to the present embodiment may include steps other than the first step, the 1.5th step, the second step, and the third step. Other steps include a sieving step. The sieving step may be a step of removing coarse particles from a suspension solution (slurry) containing toner particles by passing the suspension solution through a mesh, for example. The mesh size is adjusted appropriately depending on the particle size of the toner particles. For example, the mesh size (unit: μm) relative to the volume average particle size D50v (unit: μm) of the toner particles [D50v / mesh size] is preferably 2 or more and 6 or less, and more preferably 3 or more and 5 or less.

[0096] Other steps include a known solid-liquid separation step and a drying step. The solid-liquid separation step is not particularly limited, but from the viewpoint of productivity, it is preferable to carry out suction filtration, pressure filtration, etc. Furthermore, the drying step is also not particularly limited, but from the viewpoint of productivity, it is preferable to carry out freeze drying, flash drying, fluidized drying, vibration-type fluidized drying, etc. The toner according to this embodiment is produced by, for example, adding an external additive to the obtained dry toner particles and mixing them. The mixing can be carried out using, for example, a V blender, a Henschel mixer, a Loedige mixer, or the like. Furthermore, if necessary, coarse particles may be removed from the toner using a vibrating sieve, an air sieve, or the like.

[0097] (Mass of crystalline polyester resin in toner particles) The mass of the crystalline polyester resin contained in the toner particles relative to the mass of the entire toner particles is preferably 10% by mass or more and 30% by mass or less, more preferably 10% by mass or more and 25% by mass or less, and even more preferably 12% by mass or more and 20% by mass or less.

[0098] By setting the mass of the crystalline polyester resin contained in the toner particles to 30% by mass or less relative to the mass of the entire toner particles, the hydrophobicity of the toner particle surfaces does not become too high, and the surfactant is less likely to be adsorbed to the toner particle surfaces. Therefore, even when a surfactant containing sodium ions is used as the surfactant, the amount of sodium ions remaining on the toner particle surfaces tends to be smaller.

[0099] <Toner for developing electrostatic images> The toner obtained by the production method according to this embodiment contains toner particles and, if necessary, an external additive.

[0100] (toner particles) The toner particles are composed of a binder resin, and, if necessary, a colorant, a release agent, and other additives.

[0101] -Binder resin- The binder resin includes an amorphous polyester resin, a crystalline polyester resin, and a vinyl resin.

[0102] The "crystalline" nature of a resin refers to the presence of a clear endothermic peak rather than a stepwise change in endothermic heat in differential scanning calorimetry (DSC). Specifically, this refers to the half-width of the endothermic peak being within 10°C when measured at a heating rate of 10°C / min. On the other hand, the term "amorphous" for a resin means that the half-width exceeds 10°C, that the endothermic amount exhibits a stepwise change, or that no clear endothermic peak is observed.

[0103] Amorphous polyester resin Examples of the amorphous polyester resin include a condensation polymer of a polycarboxylic acid and a polyhydric alcohol. Note that, as the amorphous polyester resin, a commercially available product or a synthesized product may be used.

[0104] Examples of polycarboxylic acids include aliphatic dicarboxylic acids (such as oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, alkenylsuccinic acid, adipic acid, and sebacic acid), alicyclic dicarboxylic acids (such as cyclohexanedicarboxylic acid), aromatic dicarboxylic acids (such as terephthalic acid, isophthalic acid, phthalic acid, and naphthalenedicarboxylic acid), anhydrides thereof, and lower alkyl esters thereof (e.g., having 1 to 5 carbon atoms). Among these, aromatic dicarboxylic acids are preferred as polycarboxylic acids. The polycarboxylic acid may be a trivalent or higher carboxylic acid having a crosslinked or branched structure in combination with a dicarboxylic acid. Examples of the trivalent or higher carboxylic acid include trimellitic acid, pyromellitic acid, anhydrides thereof, and lower alkyl esters thereof (e.g., having 1 to 5 carbon atoms). The polycarboxylic acids may be used alone or in combination of two or more.

[0105] Examples of polyhydric alcohols include aliphatic diols (e.g., ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, etc.), alicyclic diols (e.g., cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, etc.), and aromatic diols (e.g., ethylene oxide adducts of bisphenol A, propylene oxide adducts of bisphenol A, etc.). Among these, preferred polyhydric alcohols are aromatic diols and alicyclic diols, and more preferred are aromatic diols. As the polyhydric alcohol, a trihydric or higher polyhydric alcohol having a crosslinked or branched structure may be used in combination with the diol. Examples of trihydric or higher polyhydric alcohols include glycerin, trimethylolpropane, and pentaerythritol. The polyhydric alcohols may be used alone or in combination of two or more.

[0106] The glass transition temperature (Tg) of the amorphous polyester resin is preferably 50°C or higher and 80°C or lower, and more preferably 50°C or higher and 65°C or lower. The glass transition temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC), more specifically, from the "extrapolated glass transition onset temperature" described in JIS K 7121-1987 "Method for measuring transition temperatures of plastics."

[0107] The weight average molecular weight (Mw) of the amorphous polyester resin is preferably 5,000 or more and 1,000,000 or less, and more preferably 7,000 or more and 500,000 or less. The number average molecular weight (Mn) of the amorphous polyester resin is preferably 2,000 or more and 100,000 or less. The molecular weight distribution Mw / Mn of the amorphous polyester resin is preferably 1.5 or more and 100 or less, and more preferably 2 or more and 60 or less. The weight-average molecular weight and number-average molecular weight are measured by gel permeation chromatography (GPC). Molecular weight measurements by GPC are performed using a Tosoh GPC HLC-8120GPC measuring device and a Tosoh TSKgel SuperHM-M (15 cm) column in THF solvent. The weight-average molecular weight and number-average molecular weight are calculated from the measurement results using a molecular weight calibration curve prepared with monodisperse polystyrene standard samples.

[0108] The amorphous polyester resin can be obtained by a known manufacturing method, for example, by carrying out the reaction at a polymerization temperature of 180°C or higher and 230°C or lower, reducing the pressure in the reaction system as necessary, and removing water and alcohol generated during the condensation. If the raw material monomer is not soluble or compatible at the reaction temperature, a high-boiling solvent may be added as a solubilizer to dissolve it. In this case, the polycondensation reaction is carried out while distilling off the solubilizer. If a monomer with poor compatibility is present, it is advisable to first condense the poorly compatible monomer with the acid or alcohol to be polycondensed, and then polycondense the monomer with the main component.

[0109] Crystalline polyester resin The crystalline polyester resin may be, for example, a polycondensate of a polycarboxylic acid and a polyhydric alcohol. Note that, as the crystalline polyester resin, a commercially available product or a synthesized product may be used. Here, the crystalline polyester resin is preferably a polycondensate using a polymerizable monomer having a linear aliphatic group rather than a polymerizable monomer having an aromatic group, since it easily forms a crystalline structure.

[0110] Examples of polycarboxylic acids include aliphatic dicarboxylic acids (e.g., oxalic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, etc.), aromatic dicarboxylic acids (e.g., dibasic acids such as phthalic acid, isophthalic acid, terephthalic acid, and naphthalene-2,6-dicarboxylic acid), anhydrides thereof, and lower alkyl esters thereof (e.g., having 1 to 5 carbon atoms). The polycarboxylic acid may be a tricarboxylic or higher carboxylic acid having a crosslinked or branched structure in combination with a dicarboxylic acid. Examples of the tricarboxylic acid include aromatic carboxylic acids (e.g., 1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, etc.), anhydrides thereof, and lower alkyl esters thereof (e.g., having 1 to 5 carbon atoms). As the polycarboxylic acid, a dicarboxylic acid having a sulfonic acid group and a dicarboxylic acid having an ethylenic double bond may be used in combination with these dicarboxylic acids. The polycarboxylic acids may be used alone or in combination of two or more.

[0111] Examples of polyhydric alcohols include aliphatic diols (for example, straight-chain aliphatic diols having 7 to 20 carbon atoms in the main chain). Examples of aliphatic diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, and 1,14-eicosanedecanediol. Among these, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferred as aliphatic diols. The polyhydric alcohol may be a trihydric or higher alcohol having a crosslinked or branched structure, such as glycerin, trimethylolethane, trimethylolpropane, or pentaerythritol, in combination with the diol. The polyhydric alcohols may be used alone or in combination of two or more.

[0112] Here, the polyhydric alcohol has an aliphatic diol content of 80 mol % or more, preferably 90 mol % or more.

[0113] The melting temperature of the crystalline polyester resin is preferably 50°C or higher and 100°C or lower, more preferably 55°C or higher and 90°C or lower, and even more preferably 60°C or higher and 85°C or lower. The melting temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC) using the "melting peak temperature" described in the method for determining the melting temperature in JIS K7121-1987 "Method for measuring transition temperatures of plastics."

[0114] The weight average molecular weight (Mw) of the crystalline polyester resin is preferably 6,000 or more and 35,000 or less.

[0115] The crystalline polyester resin can be obtained by a known manufacturing method, for example, in the same manner as the amorphous polyester.

[0116] Examples of vinyl resins include homopolymers of monomers such as styrenes (e.g., styrene, parachlorostyrene, α-methylstyrene, etc.), (meth)acrylic acid esters (e.g., methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, etc.), ethylenically unsaturated nitriles (e.g., acrylonitrile, methacrylonitrile, etc.), vinyl ethers (e.g., vinyl methyl ether, vinyl isobutyl ether, etc.), vinyl ketones (e.g., vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone, etc.), and olefins (e.g., ethylene, propylene, butadiene, etc.), or copolymers of two or more of these monomers.

[0117] The content of the binder resin is, for example, preferably 40% by mass to 95% by mass, more preferably 50% by mass to 90% by mass, and even more preferably 60% by mass to 85% by mass, based on the total mass of the toner particles.

[0118] -Coloring agent- Examples of colorants include carbon black, chrome yellow, Hansa Yellow, benzidine yellow, threne yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, Balkan orange, watch young red, permanent red, brilliant carmine 3B, brilliant carmine 6B, DuPont oil red, pyrazolone red, lithol red, rhodamine B lake, lake red C, pigment red, rose bengal, aniline blue, ultramarine blue, and the like. Examples of the dye include various pigments such as phosphorus blue, chalco oil blue, methylene blue chloride, phthalocyanine blue, pigment blue, phthalocyanine green, and malachite green oxalate, and various dyes such as acridine-based, xanthene-based, azo-based, benzoquinone-based, azine-based, anthraquinone-based, thioindigo-based, dioxazine-based, thiazine-based, azomethine-based, indigo-based, phthalocyanine-based, aniline black-based, polymethine-based, triphenylmethane-based, diphenylmethane-based, and thiazole-based dyes. The colorant may be used alone or in combination of two or more kinds.

[0119] The colorant may be surface-treated as needed, or may be used in combination with a dispersant. Furthermore, a plurality of colorants may be used in combination.

[0120] The content of the colorant is, for example, preferably 1% by mass or more and 30% by mass or less, and more preferably 3% by mass or more and 15% by mass or less, based on the total mass of the toner particles.

[0121] -Mold release agent- Examples of release agents include hydrocarbon waxes, natural waxes such as carnauba wax, rice wax, and candelilla wax, synthetic or mineral / petroleum waxes such as montan wax, and ester waxes such as fatty acid esters and montanic acid esters, but are not limited thereto.

[0122] The melting temperature of the release agent is preferably 50°C or higher and 110°C or lower, and more preferably 60°C or higher and 100°C or lower. The melting temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC) by using the "melting peak temperature" as described in the method for determining the melting temperature in JIS K 7121-1987 "Method for measuring transition temperatures of plastics."

[0123] The content of the release agent is, for example, preferably 1% by mass or more and 20% by mass or less, and more preferably 5% by mass or more and 15% by mass or less, based on the total mass of the toner particles.

[0124] -Other additives- Examples of other additives include well-known additives such as magnetic materials, charge control agents, inorganic powders, etc. These additives are contained in the toner particles as internal additives.

[0125] -Characteristics of toner particles, etc.- The toner particles may be toner particles of a single layer structure, or may be toner particles of a so-called core-shell structure composed of a core part (core particle) and a coating layer (shell layer) that coats the core part. Here, the toner particles having a core-shell structure may be composed of, for example, a core containing a binder resin and, if necessary, other additives such as a colorant and a release agent, and a coating layer containing the binder resin.

[0126] The volume average particle size (D50v) of the toner particles is preferably 2 μm or more and 10 μm or less, and more preferably 4 μm or more and 8 μm or less.

[0127] The various average particle sizes and particle size distribution indices of the toner particles are measured using a Coulter Multisizer II (manufactured by Beckman Coulter), and the electrolyte is measured using an ISOTON-II (manufactured by Beckman Coulter). For the measurement, 0.5 mg to 50 mg of the sample to be measured is added to 2 ml of a 5% aqueous solution of a surfactant (preferably sodium alkylbenzene sulfonate) as a dispersant, and this is then added to 100 ml to 150 ml of the electrolyte. The electrolyte solution containing the suspended sample is dispersed for 1 minute using an ultrasonic disperser, and the particle size distribution of particles with a particle size range of 2 μm to 60 μm is measured using a Coulter Multisizer II with an aperture diameter of 100 μm. The number of particles sampled is 50,000. Based on the particle size distribution measured, cumulative distributions of volume and number are drawn for each divided particle size range (channel) from the smallest diameter side, and the particle size at 16% of the cumulative total is defined as the volume particle size D16v, the number particle size D16p, the particle size at 50% of the cumulative total as the volume average particle size D50v, the cumulative number average particle size D50p, and the particle size at 84% of the cumulative total as the volume particle size D84v and the number particle size D84p. Using these, the volumetric particle size distribution index (GSDv) is (D84v / D16v) 1 / 2 , the number particle size distribution index (GSDp) is (D84p / D16p) 1 / 2 It is calculated as:

[0128] The average circularity of the toner particles is preferably 0.94 or more and 1.00 or less, and more preferably 0.95 or more and 0.98 or less.

[0129] The average circularity of toner particles is calculated by (circular equivalent perimeter) / (perimeter) [(perimeter of a circle having the same projected area as the particle image) / (perimeter of the particle projected image)]. Specifically, this value is measured by the following method. First, the toner particles to be measured are sucked and collected, forming a flat flow, and a still image of the particles is captured by instantaneously activating a strobe light, and the particle image is analyzed using a flow-type particle image analyzer (FPIA-3000 manufactured by Sysmex Corporation).The number of samples to be sampled when calculating the average circularity is 3,500. When the toner contains external additives, the toner (developer) to be measured is dispersed in water containing a surfactant, and then ultrasonic treatment is performed to obtain toner particles from which the external additives have been removed.

[0130] (external additives) Examples of external additives include inorganic particles such as SiO2, TiO2, Al2O3, CuO, ZnO, SnO2, CeO2, Fe2O3, MgO, BaO, CaO, KO, Na2O, ZrO2, CaO·SiO2, KO·(TiO2)n, Al2O3·2SiO2, CaCO3, MgCO3, BaSO4, and MgSO4.

[0131] The surfaces of inorganic particles as external additives are preferably subjected to a hydrophobic treatment. The hydrophobic treatment is carried out, for example, by immersing the inorganic particles in a hydrophobic treatment agent. The hydrophobic treatment agent is not particularly limited, and examples thereof include silane coupling agents, silicone oils, titanate coupling agents, and aluminum coupling agents. These may be used alone or in combination of two or more. The amount of the hydrophobic treatment agent is usually, for example, 1 part by mass or more and 10 parts by mass or less per 100 parts by mass of the inorganic particles.

[0132] Examples of external additives include resin particles (resin particles such as polystyrene, polymethyl methacrylate (PMMA), and melamine resin), cleaning agents (for example, metal salts of higher fatty acids such as zinc stearate, and particles of fluorine-based polymers).

[0133] The amount of the external additive added is, for example, preferably 0.01% by mass or more and 5% by mass or less, and more preferably 0.01% by mass or more and 2.0% by mass or less, based on the toner particles. [Example]

[0134] Examples will be described below, but the present invention is not limited to these examples. In the following description, unless otherwise specified, all "parts" and "%" are by mass.

[0135] Example 1 (1st step) -Resin particle dispersion preparation process- <<Preparation of amorphous polyester resin particle dispersion>> Terephthalic acid: 30 parts by mole Fumaric acid: 70 parts by mole Bisphenol A ethylene oxide adduct: 5 parts by mole Bisphenol A propylene oxide adduct: 95 parts by mole The above materials were placed in a flask equipped with a stirrer, a nitrogen inlet tube, a temperature sensor, and a distillation column, and the temperature was raised to 220°C over 1 hour, followed by adding 1 part of titanium tetraethoxide per 100 parts of the above materials. The temperature was raised to 230°C over 30 minutes while distilling off the generated water, and the dehydration condensation reaction was continued at that temperature for 1 hour. The reaction product was then cooled to obtain an amorphous polyester resin (weight average molecular weight 18,000, glass transition temperature 59°C). A vessel equipped with a temperature control device and a nitrogen purge device was charged with 40 parts of ethyl acetate and 25 parts of 2-butanol to prepare a mixed solvent, and then 100 parts of amorphous polyester resin was gradually added and dissolved. A 10% aqueous ammonia solution (equivalent to three times the molar amount of the resin's acid value) was then added and stirred for 30 minutes. The atmosphere inside the vessel was then purged with dry nitrogen, the temperature was maintained at 40°C, and 400 parts of ion-exchanged water was added dropwise to the stirred mixture to emulsify it. After the addition was complete, the emulsion was returned to 25°C, yielding a resin particle dispersion containing dispersed resin particles with a volume average particle size of 180 nm. Ion-exchanged water was added to this resin particle dispersion to adjust the solids content to 20%, yielding an amorphous polyester resin particle dispersion.

[0136] <<Preparation of crystalline polyester resin particle dispersion>> Decanedioic acid: 81 parts Hexanediol: 47 parts The above materials were charged into a flask, and the temperature was raised to 160°C over 1 hour. After confirming that the reaction system was uniformly stirred, 0.03 parts of dibutyltin oxide was added. The temperature was raised to 200°C over 6 hours while distilling off the produced water, and stirring was continued at 200°C for 4 hours. The reaction liquid was then cooled, solid-liquid separation was performed, and the solid was dried at 40°C under reduced pressure to obtain a crystalline polyester resin (weight average molecular weight 15,000, melting point 64°C). 50 parts of crystalline polyester resin, 2 parts of anionic surfactant (Neogen RK, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and 200 parts of ion-exchanged water were mixed, heated to 120°C, and thoroughly dispersed using a homogenizer (Ultra-Turrax T50, manufactured by IKA Corporation), followed by a dispersion treatment using a pressure discharge homogenizer. When the volume average particle size reached 180 nm, the particles were collected to obtain a crystalline polyester resin particle dispersion with a solids content of 20%.

[0137] <<Preparation of vinyl resin particle dispersion>> The following components were placed in a reactor equipped with a reflux condenser, a stirrer, a nitrogen inlet, and a monomer dropping port, and stirred thoroughly at room temperature (25°C) to prepare emulsion (1). Styrene (Wako Pure Chemical Industries, Ltd.): 8 parts n-Butyl acrylate (Wako Pure Chemical Industries, Ltd.): 2 parts Dodecanethiol (Wako Pure Chemical Industries, Ltd.): 0.05 parts Anionic surfactant (Newcol 271A, manufactured by Nippon Nyukazai Co., Ltd.): 4 parts Ion-exchanged water: 500 parts

[0138] Separately, the following ingredients were placed in a container equipped with a stirrer and emulsified with stirring to prepare emulsion (2). Styrene (Wako Pure Chemical Industries, Ltd.): 470 parts n-Butyl acrylate (Wako Pure Chemical Industries, Ltd.): 118 parts Dodecanethiol (Wako Pure Chemical Industries, Ltd.): 2 parts Anionic surfactant (Newcol 271A, manufactured by Nippon Nyukazai Co., Ltd.): 4 parts Ion-exchanged water: 846 parts After sufficient nitrogen substitution inside emulsion (1), the temperature was further increased to 75°C while introducing nitrogen. 50 parts of a 10% aqueous solution of ammonium persulfate (APS) was added and the mixture was heated for 20 minutes. Then, emulsion (2) was gradually added dropwise over 2 hours using a pump from the monomer dropping port of the reactor containing emulsion (1), and the reaction was continued at 75°C. After the addition of emulsion (2) was completed, 5 parts of a 10% aqueous solution of APS was added 30 minutes later while maintaining the temperature at 75°C. After another 30 minutes, 5 parts of the 10% aqueous solution were added, and the mixture was maintained at 75°C for 1.5 hours and then cooled to obtain a vinyl resin particle dispersion with a volume average particle size of 140 nm and a solids content of 30% by mass.

[0139] <<Preparation of colorant particle dispersion>> Carbon black (Mitsubishi Chemical Corporation, product name #25B): 20 parts Anionic surfactant (Neogen SC, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 2 parts Ion-exchanged water: 80 parts The above components were mixed and dispersed for 1 hour using a high-pressure impact disperser Ultimizer (HJP30006, manufactured by Sugino Machine Ltd.) to obtain a colorant particle dispersion having a volume average particle size of 180 nm and a solid content of 20% by mass.

[0140] <<Preparation of release agent particle dispersion>> Paraffin wax (manufactured by Nippon Seiro Co., Ltd., FNP92, endothermic peak onset 81°C): 45 parts Anionic surfactant (Dai-ichi Kogyo Seiyaku Co., Ltd., Neogen RK): 5 parts Ion-exchanged water: 200 parts The above ingredients were mixed and heated to 95°C, and dispersed using a homogenizer (Ultra Turrax T50, manufactured by IKA). After that, a dispersion treatment was carried out using a Manton-Gaulin high-pressure homogenizer (Gaulin), and a release agent particle dispersion liquid (solid content concentration: 20%) in which the release agent was dispersed was prepared. The volume average particle size of the release agent particles was 0.19 μm.

[0141] -Agglomerated particle formation process and fusion / coalescence process- Ion-exchanged water: 250 parts Amorphous polyester resin particle dispersion: 225 parts Crystalline polyester resin particle dispersion: 150 parts Vinyl resin particle dispersion: 75 parts Release agent particle dispersion: 75 parts Colorant particle dispersion: 38 parts Anionic surfactant (TaycaPower): 3.0 parts The above materials (hereinafter also referred to as "charged materials") were placed in a jacketed temperature-controlled stirring tank, and a 0.1N aqueous nitric acid solution was added to adjust the pH to 3.5. An aqueous polyaluminum chloride solution prepared by dissolving 2 parts of polyaluminum chloride (Oji Paper Co., Ltd., 30% powder product) in 30 parts of ion-exchange water was then added. After dispersion using a homogenizer, the mixture was heated to 45°C and maintained until the volume average particle size reached 4.9 μm. Next, 75 parts of an amorphous polyester resin particle dispersion was added and maintained for 30 minutes. Next, when the volume average particle size reached 5.2 μm, another 75 parts of an amorphous polyester resin particle dispersion was added and maintained for 30 minutes. Subsequently, 20 parts of a 10% NTA (nitrilotriacetic acid) metal salt aqueous solution (Chilest 70, Chelest Co., Ltd.) was added, and a 1N aqueous sodium hydroxide solution was added to adjust the pH to 9.0. Next, 1 part of an anionic surfactant (TaycaPower) was added, and the mixture was heated to 85°C with continued stirring and maintained for 5 hours. Next, the mixture was cooled to 20° C. at a rate of 20° C. / min to obtain a toner particle dispersion in which toner particles containing an amorphous polyester resin, a crystalline polyester resin, and a vinyl resin were dispersed.

[0142] (Step 1.5 and Step 2) The toner particle dispersion was placed in a filter press (manufactured by Tokyo Engineering Co., Ltd.) and compressed at a compression pressure of 0.4 MPa to form a cake inside the device. Water (washing water A) at 600% by mass relative to the toner particles contained in the cake was then passed through the cake. Then, a nitric acid solution (acid concentration 2 mmol / L), which was acidic water at 300% by mass relative to the toner particles, was passed through the cake.

[0143] (3rd step) Water (washing water B) in an amount of 500% by weight relative to the toner particles was passed through the inside of the cake. (Other processes) The cake was then removed and dried to obtain toner particles, which had a volume average particle size of 5.5 μm.

[0144] (External addition process) 100 parts of toner particles and 1.5 parts of hydrophobic silica (RY50, manufactured by Nippon Aerosil Co., Ltd.) were mixed and mixed for 30 seconds at a rotation speed of 13,000 rpm using a sample mill. The mixture was sieved using a vibrating sieve with 45 μm openings to obtain a toner.

[0145] <Examples 2 to 29, Example 31, Comparative Examples 1 and 2> Toner particles were obtained in the same manner as in Example 1, except that the amounts of the amorphous polyester resin particle dispersion ("AmoPES particle dispersion" in Table 1), the crystalline polyester resin particle dispersion ("CryPES particle dispersion" in Table 1), and the vinyl resin particle dispersion ("Vin particle dispersion" in Table 1) in the materials charged in the aggregate particle formation step and the fusion / coalescence step, the amount of washing water A, the amount of washing water B, the acid concentration of the acidic water, the amount of the acidic water, and the temperature of the acidic water were set as shown in Table 1. Example 30 Toner particles were obtained in the same manner as in Example 1, except that an aqueous sulfuric acid solution was used as the acidic water.

[0146] In each example, the amount of Na on the toner particle surface before the second step (Na amount Befor ) and "Na content on the toner particle surface after the second process (Na content After ) and "the amount of anions on the toner particle surface before the second process (anion amount Befor ) and "the amount of anions on the toner particle surface after the second process (anion amount After2 ) and "Amount of anions on the toner particle surface after the third step (anion amount After3 ) were measured according to the procedures previously described. The measured values ​​are shown in Table 1. In Table 1, "ΔNa" is the amount of Na on the surface of the toner particles (Na amount Befor) the amount of Na on the toner particle surface after the second step (Na amount After ) is the amount of decrease. "Δ anion" in Table 1 is the amount of anion on the surface of the toner particles before the second process (anion amount Befor ) the amount of anions on the toner particle surface after the second step (anion amount After2 ) is the increase in In addition, the "Na content" in Table 1 After3 " was derived by using the toner dried in (other steps) as toner particles after the third step and measuring with an ion chromatograph according to the procedure already described. In Table 1, "-" in Comparative Example 1 means that the second step was not carried out.

[0147] Table 2 shows the composition of the binder resin contained in the toner particles obtained in each example. The values ​​shown in Table 2 are the mass of the amorphous polyester resin, the crystalline polyester resin, or the vinyl resin relative to the mass of the entire toner particles.

[0148] <Evaluation> (Image evaluation) The developer prepared by the following procedure was filled into the developing device of a modified "DocuCentreColor400 (manufactured by Fujifilm Business Innovation Co., Ltd.)" machine, and image evaluation was carried out.

[0149] - Developer production procedure - <<Creating a carrier>> 100 parts of ferrite particles (manufactured by Powder Tech Co., Ltd., average particle size 50 μm) and 1.5 parts of polymethyl methacrylate resin (manufactured by Mitsubishi Rayon Co., Ltd., weight average molecular weight 95,000, proportion of components with a weight average molecular weight of 10,000 or less is 5%) were placed in a pressure kneader together with 500 parts of toluene, stirred and mixed at room temperature for 15 minutes, then heated to 70°C while mixing under reduced pressure to distill off the toluene, then cooled and classified using a 105 μm sieve to obtain a resin-coated carrier. << Developer Preparation >> 10 parts of the toner obtained in each example and 100 parts of the resin-coated carrier were placed in a V-type blender and stirred for 20 minutes, and then sieved through a vibrating sieve with 212 μm openings to obtain a developer.

[0150] -Actual machine evaluation- 1000 images with an image density of 40% were printed in a high-temperature, high-humidity environment (30°C, 85% RH), and then 1000 copies of the same image were printed in a low-temperature, low-humidity environment (10°C, 15% RH). The same procedure was repeated three times. The same image was then printed under conditions of 20°C, 50% RH, and the images were visually inspected and evaluated for color streaks and color points according to the following evaluation criteria. The evaluation results are shown in Table 2.

[0151] <<Color streak evaluation criteria>> A (◯): No color streaks are visible, and a very good image is obtained. B (Δ): Color streaks are slightly noticeable, but are at an acceptable level, and a good image is obtained. C(x): Color streaks are clearly visible to the naked eye.

[0152] <<Color point evaluation criteria>> A (◯): No color points are recognized, and a very good image is obtained. B (Δ): Color spots are slightly noticeable, but are at an acceptable level, and a good image is obtained. C(x): The color points are clearly visible to the naked eye.

[0153] (Percentage rating) After removing the cake in each example (other steps), 100 g of the cake was taken out for yield evaluation. The amount of moisture contained in the cake taken out for yield evaluation was measured and subtracted from the mass of the cake taken out for yield evaluation to calculate the mass of the toner particles contained in the cake taken out for yield evaluation (hereinafter referred to as mass A). The entire cake taken for yield evaluation was dried to obtain dried toner particles. The entire dried toner particles were sieved using a mesh with a mesh opening of 100 μm, and the mass of the toner particles that passed through the mesh (hereinafter referred to as mass B) was measured. The yield was calculated using the formula below, and the yield was evaluated based on the yield value according to the following evaluation criteria. Note that a higher yield value indicates that toner particles containing fewer coarse particles are obtained. The evaluation results are shown in Table 2. Formula: Yield (%) = Mass B ÷ Mass A

[0154] <<Evaluation criteria for earning rate>> A(〇): The yield rate is 95% or more. B (△): The yield value is 90% or more and less than 95%. C(×): The yield value is less than 90%.

[0155] [Table 1-1]

[0156] [Table 1-2]

[0157] [Table 2-1]

[0158] [Table 2-2]

[0159] From the above results, it can be seen that the toner manufacturing method of this example is a toner manufacturing method that can obtain a toner that suppresses color streaks or color points.

Claims

1. A first step of obtaining toner particles containing an amorphous polyester resin, a crystalline polyester resin, and a vinyl resin by a wet process; a 1.5 step of adding the toner particles to a filter chamber of a filter press and squeezing them to form a cake layer of the toner particles, and bringing washing water A into contact with the toner particles in the cake layer; a second step of contacting the toner particles in the cake layer with acidic water, in this order.

2. The amount of Na on the surface of the toner particles before the second process (Na amount Ｂｅｆｏｒ ) the amount of Na on the toner particle surface after the second step (Na amount Ａｆｔｅｒ ) is 0.10 mg / L or more and 2.0 mg / L or less, The amount of Na on the surface of the toner particles after the second process (Na amount Ａｆｔｅｒ 2. The method for producing a toner for developing electrostatic images according to claim 1, wherein the ionic surfactant concentration is 0.05 mg / L or more and 0.4 mg / L or less.

3. a third step of contacting the toner particles with washing water B after the second step, The amount of anions on the surface of the toner particles before the second process (anion amount Ｂｅｆｏｒ ) the amount of anions on the toner particle surface after the second step (anion amount Ａｆｔｅｒ２ ) is 1 mg / L or more and 5 mg / L or less, The amount of anions on the surface of the toner particles after the third step (anion amount Ａｆｔｅｒ３ 3. The method for producing a toner for developing electrostatic images according to claim 1, wherein the concentration of the toner is 0.001 mg / L or more and 0.1 mg / L or less.

4. The method for producing toner for developing electrostatic images according to claim 3, wherein the third step is a step of bringing cleaning water B into contact with the toner particles in the cake layer.

5. 5. The method for producing a toner for developing electrostatic images according to claim 1, wherein the acidic water has an acid concentration of 0.5 mmol / L or more and 8 mmol / L or less.

6. 6. The method for producing a toner for developing electrostatic images according to claim 5, wherein the temperature of the acidic water having an acid concentration of 0.5 mmol / L or more and 8 mmol / L or less is 35[deg.] C. or less.

7. 7. The method for producing a toner for developing electrostatic images according to claim 1, wherein the acidic water is an aqueous solution of nitric acid.

8. 8. The method for producing a toner for developing electrostatic images according to claim 1, wherein the mass of the washing water A is 150% by mass or more and 2000% by mass or less with respect to the mass of the entire toner particles.

9. 9. The method for producing a toner for developing electrostatic images according to claim 1, wherein a mass of the crystalline polyester resin contained in the toner particles is 10% by mass or more and 30% by mass or less with respect to a mass of the entire toner particles.

Images