Method for manufacturing toner for electrostatic image development

Abstract

To provide a method for manufacturing a toner for developing electrostatic charge images that has high transfer efficiency, and with which color points are suppressed.SOLUTION: Provided is a method for manufacturing a toner for developing electrostatic charge images in which a step for coagulating at least resin particles in a dispersed liquid including the resin particles and forming coagulated particles, and a step for heating a coagulated particle dispersed liquid and fusing-unifying the coagulated particles in a fusion-unification vessel that includes a base having volatility and accommodates the coagulated particle dispersed liquid in which the coagulated particles are dispersed, satisfy at least one of conditions (1) to (3) below. (1): the total area rate of one or a plurality of openings present at the top of the fusion-unification vessel is 5 cm2 / m3 or greater per unit amount of the coagulated particle dispersed liquid; (2): the coagulated particles are fused and unified while the inside of the fusion-unification vessel is evacuated to the range of (atmospheric pressure -0.5) kPa or below; (3): the coagulated particles are fused and unified while a gas is blown into the fusion-unification vessel at a rate of 5 L / (min-m3) or greater per unit amount of the coagulated particle dispersed liquid in the fusion-unification vessel.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to a method for manufacturing toner for electrostatic image development. [Background technology]

[0002] For example, Patent Document 1 discloses "a method for producing unified resin particles, characterized by comprising: a unification step in which an aggregated resin particle slurry, in which at least resin fine particles containing resin have aggregated, is dispersed in a liquid medium, is heated to a predetermined temperature and pressurized to a pressure of 0.5 MPa to 15 MPa, and flowed through a pipe to obtain an unified resin particle slurry in which unified resin particles, in which aggregated resin particles have coalesced, are dispersed in a liquid medium; and a cooling and depressurization step in which the unified resin particle slurry, which is in a heated and pressurized state flowing through a pipe, is cooled to a predetermined temperature and depressurized to a predetermined pressure."

[0003] Furthermore, Patent Document 2 discloses "a method for producing electrostatic image developing toner containing toner particles containing at least a binder resin and a colorant, comprising an aggregation step of forming aggregates of binder resin particles and colorant particles in an aqueous medium, and a fusion step of fusing the aggregates to form a toner particle dispersion, wherein at least one of the aggregation step and the fusion step includes a volatile organic matter removal step of discharging volatile organic matter vaporized by heating from the reaction vessel forming the toner particle dispersion."

[0004] Furthermore, Patent Document 3 discloses "a method for manufacturing electrostatic image developing toner, comprising adding a flocculant and a stabilizer to an aqueous dispersion containing at least polymer microparticles and colorant microparticles, associating a large number of the microparticles, and thermally fusing the associated particles at a temperature above the glass transition temperature of the polymer microparticles, characterized in that the concentration of at least one of the flocculant and the stabilizer is changed during thermal fusion." [Prior art documents] [Patent Documents]

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] The problem of the present invention is to aggregate at least the resin particles in a dispersion containing resin particles to form aggregated particles, and to heat the aggregated particle dispersion containing a volatile base and containing the aggregated particles dispersed therein in a fusion and unification tank, and to fuse and unify the aggregated particles. In the manufacturing method of an electrostatic charge image developing toner having a step of fusing and unifying the aggregated particles, the step of fusing and unifying the aggregated particles has a total area ratio of the openings of 5 cm per unit amount of the aggregated particle dispersion 2 / m 3 less than that, and to provide a manufacturing method of an electrostatic charge image developing toner having a higher transfer efficiency and suppressed color spots compared to the case where the step of fusing and unifying the aggregated particles is performed in a fusion and unification tank having no wind under normal pressure.

Means for Solving the Problems

[0007] Specific means for solving the above problems include the following aspects. <1> In a dispersion containing resin particles, a step of aggregating at least the resin particles to form aggregated particles; A step of heating the aggregated particle dispersion in a fusion and unification tank containing a volatile base and containing the aggregated particles dispersed therein to fuse and unify the aggregated particles; having, The method for manufacturing an electrostatic charge image developing toner, wherein the step of fusing and unifying the aggregated particles satisfies at least one of the following conditions (1) to (3). Condition (1): having one or more openings at the upper part of the fusion and unification tank, and the total area ratio of the openings being 5 cm per unit amount of the aggregated particle dispersion liquid 2 / m 3 or more. Condition (2): fusing and unifying the aggregated particles while depressurizing the inside of the fusion and unification tank to a range of (atmospheric pressure - 0.5) kPa or less. Condition (3): fusing and unifying the aggregated particles while blowing a gas with an air volume of 5 L / (min·m 3 ) or more into the fusion and unification tank. <2> The method for producing a toner for electrostatic charge image development according to <1>, wherein the step of fusing and unifying the aggregated particles satisfies at least one of the following conditions (11) to (13). Condition (11): having one or more openings at the upper part of the fusion and unification tank, and the total area ratio of the openings being 5 cm per unit amount of the aggregated particle dispersion liquid 2 / m 3 or more and 8000 cm 2 / m 3 or less. Condition (12): fusing and unifying the aggregated particles while depressurizing the inside of the fusion and unification tank to a range of (atmospheric pressure - 50) kPa or more and (atmospheric pressure - 0.5) kPa or less. Condition (13): fusing and unifying the aggregated particles while blowing a gas with an air volume of 5 L / (min·m 3 ) or more and 150 L / (min·m 3 ) or less into the fusion and unification tank. <3> In the above-mentioned conditions (1) and (11), the number of openings at the upper part of the fusion and unification tank is 2 or more and 30 or less, and the method for producing a toner for electrostatic charge image development according to <1> or <2>. <4> The number of openings at the upper part of the fusion and unification tank is 3 or more and 20 or less, and the method for producing a toner for electrostatic charge image development according to <3>. <5> In the process of fusing and integrating the aggregated particles, a mixed aqueous solution of acid and surfactant is added to the aggregated particle dispersion, which has reached a temperature of (the glass transition temperature Tg of the resin particles) or (the glass transition temperature Tg + 50°C). <1> ~ <4> A method for manufacturing electrostatic image developing toner as described in any one of the items. <6> When the mixed aqueous solution of the acid and surfactant is added, the temperature of the aggregated particle dispersion is between (the glass transition temperature Tg + 5°C of the resin particles) and (the glass transition temperature Tg + 40°C). <5> A method for manufacturing toner for developing charge images as described above. <7> In the step of fusing and uniting the aggregated particles, the rate of heating of the aggregated particle dispersion from the start of heating to the fusing and uniting temperature is 0.05°C / min or more and 1°C / min or less. <1> ~ <6> A method for manufacturing electrostatic image developing toner as described in any one of the items. <8> The heating rate is 0.1°C / min or more and 0.5°C / min or less. <7> A method for manufacturing toner for electrostatic image developing as described above. <9> The step of fusing and merging the aggregated particles is a step of fusing and merging the aggregated particles while stirring the aggregated particle dispersion in the fusing and merging tank, In the agglomerated particle dispersion liquid being stirred, the ratio (H / D) of the difference H between the liquid level at the wall of the fusion / unification tank and the liquid level at the stirring axis, with respect to the radius D of the fusion / unification tank, is 0.01 or more and 2 or less. <1> ~ <8> A method for manufacturing electrostatic image developing toner as described in any one of the items. <10> In the agglomerated particle dispersion liquid being stirred, the ratio (H / D) of the difference H between the liquid level at the wall of the fusion / unification tank and the liquid level at the stirring axis, with respect to the radius D of the fusion / unification tank, is 0.05 or more and 1 or less. <9> A method for manufacturing toner for electrostatic image developing as described above. <11> The process includes a step of using an organic solvent and an aqueous medium to emulsify a resin, then vacuum distilling the resulting emulsion to remove the organic solvent from the emulsion to form a dispersion containing the resin particles. In the step of forming a dispersion containing the resin particles, the volatile base is used as a neutralizing agent to neutralize the resin. <1> ~ <10> A method for manufacturing electrostatic image developing toner as described in any one of the items. <12> The method for producing a toner for electrostatic image developing according to claim 11, wherein the volatile base is ammonia. <13> The aforementioned resin particles are particles containing a resin with an acid value of 5 mg KOH / g or more and 40 mg KOH / g or less. <1> ~ <12> A method for manufacturing electrostatic image developing toner as described in any one of the items. <14> The aforementioned resin is a polyester resin. <13> A method for manufacturing toner for electrostatic image developing as described above. <15> A step of agglomerating at least the resin particles in a dispersion containing resin particles to form aggregated particles, A process of heating the aggregated particle dispersion, which contains a volatile base and the aggregated particles, in a fusion / combination tank, thereby fusing and combining the aggregated particles, It has, A method for manufacturing toner for electrostatic image developing, wherein, in the step of fusing and unifying the aggregated particles, the amount of volatile base in the aggregated particle dispersion when the aggregated particle dispersion reaches the fusing and unification temperature is 10% by mass or more and 98% by mass or less, relative to the amount of volatile base in the aggregated particle dispersion when the heating of the aggregated particle dispersion begins. <16> In the step of fusing and integrating the aggregated particles, the amount of the volatile base in the aggregated particle dispersion at the start of heating of the aggregated particle dispersion is 0.005% by mass or more and 1.0% by mass or less relative to the solid content of the aggregated particle dispersion. <15> A method for manufacturing toner for electrostatic image developing as described above. <17> In the process of fusing and unifying the aggregated particles, the pH of the aggregated particle dispersion at the start of heating is 6.5 or higher and 9.5 or lower, and the pH of the aggregated particle dispersion at the time the fusing and unification temperature is reached is 6 or higher and 9 or lower. <15> or <16> A method for manufacturing toner for electrostatic image developing as described above. [Effects of the Invention]

[0008] <1> According to the invention relating to the present invention, a method for manufacturing electrostatic image developing toner comprises the steps of: a step of agglomerating at least the resin particles in a dispersion containing resin particles to form aggregated particles; and a step of heating the aggregated particle dispersion in a fusion / combination tank containing a volatile base and an aggregated particle dispersion in which the aggregated particles are dispersed, thereby fusing and combining the aggregated particles, wherein in the step of fusing and combining the aggregated particles, the total area ratio of the openings is 5 cm per unit volume of the aggregated particle dispersion. 2 / m 3 A method for manufacturing electrostatic image developing toner is provided, which has a smaller opening and, compared to a process in which aggregated particles are fused and combined in a fusion / coalition tank under normal pressure and in a windless state, has higher transfer efficiency and suppresses color spots.

[0009] <2> According to the invention relating to this invention, a method for manufacturing electrostatic image developing toner is provided in which the step of fusing and unifying aggregated particles has higher transfer efficiency and suppresses color spots compared to the case in which none of the above conditions (11) to (13) are met.

[0010] <3> According to the invention, in conditions (1) and (11), a method for manufacturing electrostatic image developing toner is provided that has higher transfer efficiency and suppresses color spots compared to the case where there is one opening at the top of the fusion / unification tank. <4> According to the invention, in conditions (1) and (11), a method for manufacturing electrostatic image developing toner is provided that has higher transfer efficiency and suppresses color spots compared to the case where there are two openings at the top of the fusion / unification tank.

[0011] <5> According to the invention, a method for producing electrostatic image developing toner is provided in which, in the step of fusing and integrating aggregated particles, a mixed aqueous solution of acid and surfactant is added to an aggregated particle dispersion that has reached a temperature below (glass transition temperature Tg) or above (glass transition temperature Tg + 50°C), resulting in higher transfer efficiency and suppressed color spots. <6> According to the invention, a method for producing electrostatic image developing toner is provided in which, compared to the case in which a mixed aqueous solution of acid and surfactant is added to an aggregated particle dispersion that has reached a temperature below (the glass transition temperature Tg + 5°C of resin particles) or above (the glass transition temperature Tg + 40°C) in the step of fusing and integrating aggregated particles, the transfer efficiency is higher and color spots are suppressed.

[0012] <7> According to the invention, a method for manufacturing electrostatic image developing toner is provided in which, in the step of fusing and unifying aggregated particles, the heating rate from the start of heating of the aggregated particle dispersion to the fusing and unification temperature is less than 0.05°C / min or greater than 1°C / min, compared to cases where the transfer efficiency is higher and color spots are suppressed. <8> According to the invention, a method for manufacturing electrostatic image developing toner is provided in which, in the step of fusing and unifying aggregated particles, the heating rate from the start of heating of the aggregated particle dispersion to the fusing and unification temperature is less than 0.1°C / min or greater than 0.5°C / min, compared to cases where the transfer efficiency is higher and color spots are suppressed.

[0013] <9> According to the invention, a method for manufacturing electrostatic image developing toner is provided in which the transfer efficiency is higher and color spots are suppressed compared to cases where the ratio (H / D) of the difference between the liquid level at the wall surface of the fusion / unification tank and the liquid level at the stirring axis, with respect to the radius D of the fusion / unification tank, is less than 0.01 or greater than 2 in a dispersion of aggregated particles during stirring. <10> According to the invention, a method for manufacturing electrostatic image developing toner is provided in which the transfer efficiency is higher and color spots are suppressed compared to cases where the ratio (H / D) of the difference between the liquid level at the wall surface of the fusion / unification tank and the liquid level at the stirring axis, with respect to the radius D of the fusion / unification tank, is less than 0.05 or greater than 1 in a dispersion of aggregated particles during stirring.

[0014] <11> According to the invention, a method for manufacturing electrostatic image developing toner is provided in which, compared to the case in which a volatile base is added to a dispersion containing resin particles in the step of forming aggregated particles, the transfer efficiency is higher and color spots are suppressed.

[0015] <12> According to the invention, a method for manufacturing toner for electrostatic image development is provided, which has higher transfer efficiency and suppresses color spots compared to the case where the volatile base is methylamine.

[0016] <13> According to the invention, a method for manufacturing electrostatic image developing toner, comprising the steps of: forming aggregated particles in a dispersion containing resin particles, including at least the resin particles and containing a volatile base; and heating the aggregated particle dispersion in a fusion / combination tank containing the dispersed aggregated particles to fuse / combine the aggregated particles, wherein the fusion / combination step involves a total area ratio of openings of 5 cm² per unit volume of the aggregated particle dispersion. 2 / m 3 Compared to a process in which aggregated particles are fused and combined in a fusion / combination tank having an opening of less than 5 mg KOH / g and under normal pressure and airless conditions, the present invention provides a method for manufacturing electrostatic image developing toner that has high transfer efficiency and suppresses color spots, even when the acid value of the resin particles is between 5 mg KOH / g and 40 mg KOH / g.

[0017] <14> According to the invention, a method for manufacturing electrostatic image developing toner, comprising the steps of: forming aggregated particles in a dispersion containing resin particles, including at least the resin particles and containing a volatile base; and heating the aggregated particle dispersion in a fusion / combination tank containing the dispersed aggregated particles to fuse / combine the aggregated particles, wherein the fusion / combination step involves a total area ratio of openings of 5 cm² per unit volume of the aggregated particle dispersion. 2 / m 3 Compared to a process in which aggregated particles are fused and combined in a fusion / combination tank having an opening of less than 100%, under normal pressure and in a windless state, the present invention provides a method for manufacturing electrostatic image developing toner that has high transfer efficiency and suppresses color spots, even when the resin particles contain polyester resin.

[0018] <15> According to the present invention, a method for manufacturing electrostatic image developing toner is provided, which has higher transfer efficiency and suppresses color spots compared to a method for manufacturing electrostatic image developing toner in which the amount of volatile base in the electrostatic image developing toner at the time the electrostatic image developing toner reaches the fusion and combination temperature exceeds 98% by mass, compared to a method for manufacturing electrostatic image developing toner in which the amount of volatile base in the electrostatic image developing toner at the time the electrostatic image developing toner reaches the fusion and combination temperature is compared to the amount of volatile base in the electrostatic image developing toner at the start of heating of is provided, <16> According to the invention, a method for manufacturing electrostatic image developing toner is provided in which, in the step of fusing and integrating aggregated particles, the amount of volatile base in the aggregated particle dispersion at the start of heating of the aggregated particle dispersion exceeds 1.0% by mass relative to the solid content of the aggregated particle dispersion, compared to the case where the transfer efficiency is higher and color spots are suppressed. <17> According to the invention, a method for manufacturing electrostatic image developing toner is provided that has higher transfer efficiency and suppresses color spots compared to the case where the pH of the aggregated particle dispersion exceeds 9 when the aggregated particle dispersion reaches the fusion / unification temperature. [Brief explanation of the drawing]

[0019] [Figure 1] Figure 1 is a schematic diagram showing an example of a fusion / combination tank used in the toner manufacturing method according to this embodiment. Figure 1(A) is a schematic top view of the fusion / combination tank, and Figure 1(B) is a schematic front cross-sectional view. [Figure 2] Figure 2 is a schematic diagram showing another example of a fusion / combination tank used in the toner manufacturing method according to this embodiment. [Figure 3] Figure 3 is a schematic diagram showing another example of a fusion / combination tank used in the toner manufacturing method according to this embodiment. [Modes for carrying out the invention]

[0020] The following describes an example embodiment of the present invention. These descriptions and examples are illustrative of the present invention and do not limit it.

[0021] In this specification, numerical ranges indicated using "~" represent a range that includes the numbers before and after "~" as the minimum and maximum values, respectively. In numerical ranges described stepwise within this specification, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range described stepwise. Furthermore, in numerical ranges described within this specification, the upper or lower limit of that range may be replaced with the values ​​shown in the examples.

[0022] In this specification, the term "process" includes not only independent processes but also processes that cannot be clearly distinguished from other processes, provided that their intended purpose is achieved.

[0023] When embodiments are described herein with reference to the drawings, the configuration of the embodiments is not limited to the configuration shown in the drawings. Furthermore, the sizes of the components in each figure are conceptual, and the relative relationships between the components are not limited thereto.

[0024] In this specification, each component may contain multiple types of the corresponding substance. When referring to the amount of each component in a composition in this disclosure, if there are multiple types of the substance corresponding to each component in the composition, it means the total amount of those multiple types of substances present in the composition unless otherwise specified.

[0025] In this specification, "electrostatic image developing toner" is also referred to as "toner."

[0026] In this specification, "volatile base" refers to a base having a boiling point of 100°C or lower at atmospheric pressure.

[0027] <Toner manufacturing method> The toner manufacturing method according to this embodiment comprises the steps of: a step of agglomerating at least resin particles in a dispersion containing resin particles to form agglomerated particles (hereinafter also referred to as the "aggregation step"); and a step of heating the agglomerated particle dispersion containing a volatile base and dispersed with agglomerated particles in a fusion / combination tank to fuse / combine the agglomerated particles (hereinafter also referred to as the "fusion / combination" step).

[0028] Furthermore, in the toner manufacturing method according to the first embodiment, the step of fusing and unifying the aggregated particles satisfies at least one of the following conditions (1) to (3). Condition (1): The fusion / combination tank has one or more openings at the top, and the total area ratio of the openings is 5 cm per unit volume of the aggregated particle dispersion. 2 / m 3 That's all. Condition (2): The aggregated particles are fused and combined in the fusion / combination tank under reduced pressure to a range of (atmospheric pressure - 0.5) kPa or less. Condition (3): 5 L / (min·m) per unit volume of aggregated particle dispersion in the fusion / coalition tank. 3 The aggregated particles are fused and combined while a gas with an airflow volume of ) or more is blown into the fusion / combination tank.

[0029] On the other hand, in the toner manufacturing method according to the second embodiment, in the step of fusing and unifying the aggregated particles, the amount of base in the aggregated particle dispersion when the fusing and unification temperature of the aggregated particle dispersion is reached is 10% by mass or more and 98% by mass or less, relative to the amount of base in the aggregated particle dispersion when heating of the aggregated particle dispersion begins.

[0030] In the toner manufacturing methods according to the first and second embodiments, toner with high transfer efficiency and suppressed color spots is manufactured by the above method. The reason for this is presumed to be as follows.

[0031] One method for producing toner particles involves an aggregation process to form aggregated particles and a fusion / unification process to fuse and combine the aggregated particles. In the fusion and coalescence process, toner particles are formed while suppressing the generation of coarse particles due to aggregation of toner particles. In addition, the fusion and coalescence of resin particles are advanced to adjust the circularity of the toner particles to the desired range. If coarse particles are mixed into the toner, color spots will appear in the image, degrading image quality. Also, if it takes a long time to adjust the circularity, that is, if the fusion / combination time is prolonged, the resin will decompose due to heat, and the decomposed components will remain in the toner, reducing transfer efficiency.

[0032] On the other hand, in conventional toner manufacturing methods, a method has been proposed in which the concentration of at least one of the coagulant (specifically, a metal salt, etc.) and the stabilizer (specifically, a surfactant, etc.) is changed in the fusion and coalescence step to suppress the generation of coarse powder particles while promoting the fusion and coalescence of aggregated particles (see, for example, Patent Document 3). However, in the above manufacturing method, if a flocculant is added during the fusion and coalescence process, the fusion and coalescence of the aggregated particles is promoted, but the cohesive force between toner particles also increases, promoting the generation of coarse particles. If a stabilizer is added to suppress the generation of coarse powder due to the flocculant, a large amount of stabilizer must be added. As a result, the stabilizer remains in the toner particles, reducing the transfer efficiency due to charge injection.

[0033] Furthermore, in the fusion process, a manufacturing method is known in which a mixed aqueous solution of acid and surfactant is added to the agglomerated particle dispersion to promote the fusion and coalescence of the agglomerated particles. However, in this method as well, excessive aggregation is promoted by the acid, making it easy for coarse particles to be generated. In addition, the residue of surfactant on the toner particles reduces the transfer efficiency by charge injection.

[0034] In the toner manufacturing process, volatile bases are used, for example, as a neutralizing agent for resins in the resin particle manufacturing process, and as an anti-coagulation agent to raise the pH of the dispersion and stop coagulation in the coagulation process. In other words, in the fusion and coalescence process, aggregated particles fuse and coalesce in the presence of a volatile base. Furthermore, if the amount of volatile base in the dispersion can be reduced during the fusion and coalescence process, the pH of the dispersion will decrease, promoting the fusion and coalescence of the aggregated particles. This makes it possible to omit or reduce the amount of the above-mentioned flocculant or acid added, thereby suppressing the generation of coarse particles. Furthermore, since the generation of coarse particles is suppressed, the amount of surfactant added can be reduced, and the residue of surfactant on the toner particles is suppressed. In addition, by reducing the amount of volatile bases, the fusion and coalescence time can be shortened, thermal decomposition of the resin is reduced, and the residue of decomposed components in the toner particles is suppressed. As a result, the decrease in transfer efficiency due to charge injection is suppressed.

[0035] Therefore, in the toner manufacturing method according to the first embodiment, by satisfying at least one of the above conditions (1) to (3), the amount of volatile base in the dispersion is reduced in the fusion and unification step. As a result, the generation of coarse particles and the decrease in transfer efficiency due to charge injection are suppressed. Specifically, under the above condition (1), a fusion / combination tank is used that has one or more openings at the top with a specific opening area ratio, and the volatile base is discharged outside the tank system through the openings. As a result, the amount of volatile base in the dispersion is reduced during the fusion / combination process. Under the above condition (2), the volatilization of the base in the dispersion is promoted by reducing the pressure inside the fusion / combination tank. As a result, the amount of volatile base in the dispersion is reduced during the fusion / combination process. Under condition (3) above, gas is blown into the fusion / combination tank to promote the volatilization of the base in the dispersion. As a result, the amount of volatile base in the dispersion is reduced during the fusion / combination process.

[0036] On the other hand, in the toner manufacturing method according to the second embodiment, in the fusion and unification step, the amount of base in the agglomerated particle dispersion when the agglomerated particle dispersion reaches the fusion and unification temperature is 10% by mass or more and 98% by mass or less, relative to the amount of base in the agglomerated particle dispersion when the heating of the agglomerated particle dispersion starts. This reduces the amount of volatile bases in the dispersion during the fusion and coalescence process, thereby suppressing the generation of coarse particles. Furthermore, since the generation of coarse particles is suppressed, the amount of surfactant added can be reduced, and the residue of surfactant on the toner particles is suppressed. In addition, by reducing the amount of volatile bases, the fusion and coalescence time can be shortened, thermal decomposition of the resin is reduced, and the residue of decomposed components in the toner particles is suppressed. As a result, the decrease in transfer efficiency due to charge injection is suppressed.

[0037] From the above, it is presumed that the toner manufacturing methods according to the first and second embodiments produce toner with high transfer efficiency and suppressed color spots.

[0038] The following describes in detail the toner manufacturing methods that correspond to both the toner manufacturing methods according to the first and second embodiments (hereinafter also referred to as "the toner manufacturing method according to this embodiment"). However, an example of the toner manufacturing method of the present invention is any toner manufacturing method that corresponds to either the toner manufacturing method according to the first or second embodiment.

[0039] The toner manufacturing method according to this embodiment includes at least an aggregation step of agglomerating resin particles to form aggregated particles, and a fusion and fusion step of fusing and merging the aggregated particles. The following explanation describes, as an example, a method for obtaining toner particles containing a colorant and a release agent. However, the colorant and release agent are used as needed. Of course, other additives besides colorants and release agents may also be used. Here, the resin particles are the particles that become the binder resin for the resulting toner particles.

[0040] (Particle dispersion preparation process) In the toner manufacturing method according to this embodiment, a resin particle dispersion, a colorant particle dispersion, and a mold release agent dispersion are prepared for use in the aggregation step.

[0041] -Resin particle dispersion- A resin particle dispersion is prepared, for example, by dispersing resin particles in a dispersion medium using a surfactant.

[0042] Examples of dispersion media used in resin particle dispersions include aqueous media. Examples of aqueous media include water such as distilled water and deionized water, and alcohols. These may be used individually or in combination of two or more.

[0043] Examples of surfactants include anionic surfactants such as sulfate esters, sulfonates, phosphates, and soaps; cationic surfactants such as amine salts and quaternary ammonium salts; and nonionic surfactants such as polyethylene glycol, alkylphenol ethylene oxide adducts, and polyhydric alcohols. Among these, anionic surfactants and cationic surfactants are particularly noteworthy. Nonionic surfactants may be used in combination with anionic or cationic surfactants. Surfactants may be used individually or in combination of two or more types.

[0044] In resin particle dispersions, common dispersion methods for dispersing resin particles in a dispersion medium include, for example, rotary shear homogenizers, ball mills with media, sand mills, and dyno mills. Depending on the type of resin particles, the resin particles may also be dispersed in the resin particle dispersion using, for example, a phase inversion emulsification method.

[0045] Here, it is preferable that the resin particle dispersion be produced by a phase inversion emulsification method. In other words, in the toner production method according to this embodiment, it is preferable to have a step of removing the organic solvent from the phase inversion emulsified solution, which is obtained by phase inversion emulsification of the resin using an organic solvent and an aqueous medium, by vacuum distillation to form a dispersion containing resin particles. Furthermore, in the step of forming the dispersion containing resin particles, it is preferable to neutralize the resin using a volatile base as a neutralizing agent. In the phase inversion emulsification method, using a volatile base as a neutralizing agent for the resin results in the base being incorporated into the interior of the resulting resin particles. In this state, reducing the amount of base during the fusion / coalition process promotes fusion / coalition within the resin particles. As a result, the generation of coarse particles is suppressed, and the amount of acids, surfactants, etc., used is reduced. In addition, the fusion / coalition time is shortened. Consequently, it becomes easier to manufacture toners with high transfer efficiency and suppressed color spots.

[0046] First, the phase-inversion emulsion is obtained by the phase-inversion emulsification method. Phase inversion emulsification is a method in which a resin is dissolved in an organic solvent in which it is soluble, and a continuous phase oil phase dispersion (i.e., the O phase of the resin solution) is dissolved in an organic solvent in which the resin is soluble. By adding an aqueous medium (i.e., the W phase), the resin is converted from W / O to O / W (so-called phase inversion), the oil phase dispersion becomes a discontinuous phase, and the resin is dispersed in the aqueous medium in particulate form.

[0047] Examples of methods for producing a phase-inversion emulsion include the following: 1) A method of dissolving a resin in an organic solvent, adding a neutralizing agent to the resulting resin solution to neutralize the resin, and then adding an aqueous medium to the resin solution to perform phase inversion emulsification. 2) A method of dissolving the resin in a solvent containing an organic solvent and a neutralizing agent, neutralizing the resin, and then adding an aqueous medium to the resin solution to perform phase inversion emulsification. 3) A method of dissolving a resin in a solvent containing an organic solvent, a neutralizing agent, and an aqueous medium, neutralizing the resin, and then adding the aqueous medium to the resin solution to perform phase inversion emulsification.

[0048] The production of the phase-inversion emulsion is carried out using, for example, a well-known emulsification apparatus such as an emulsification tank with stirring blades. When dissolving a resin in an organic solvent, in addition to the resin and organic solvent, an aqueous solvent and a neutralizing agent may also be mixed together. There are no particular restrictions on the order in which the resin and organic solvent are added to the emulsification tank. However, if the resin is easily soluble in the organic solvent, it is preferable from the viewpoint of dissolution time to add the resin after adding all or some of the organic solvent. The piping used to introduce the resin into the emulsification tank can be freely selected depending on the resin's grinding diameter and other factors. For example, piping that moves up and down to the bottom of the emulsification tank may be used to suppress dust dispersion during resin introduction. There are no particular restrictions on the position, number, or shape of the nozzles used to add water to the resin solution obtained by dissolving the resin in an organic solvent. For example, the nozzles may be submerged in the liquid. In the case of large-scale equipment, it is preferable to add water using two or more pipes, or to use a shower-type nozzle to diffuse the water from the top of the emulsification tank to the liquid surface.

[0049] Next, the organic solvent is removed from the phase-inversion emulsion. Specifically, for example, the organic solvent is removed from the phase-inversion emulsion by vacuum distillation. Vacuum distillation removes the organic solvent from the phase inversion emulsion by evaporating the organic solvent and aqueous medium while stirring and heating. This yields a resin particle dispersion.

[0050] In addition, in vacuum distillation, well-known methods can be employed, such as a method using a vacuum distillation tank with a stirring device to perform vacuum distillation while bubbling an inert gas, or a method called a wall wetter, in which the phase-inverted emulsion in the vacuum distillation tank is drawn upwards, forming a liquid film on the heat transfer surface of the tank above the liquid surface, while performing vacuum distillation.

[0051] Next, we will explain the various materials used in the phase inversion emulsification method.

[0052] ·resin Any resin capable of phase-inversion emulsification will suffice as the resin. Examples of resins include vinyl resins consisting of 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 (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. Examples of resins include non-vinyl resins such as epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, and modified rosin; mixtures of these with the aforementioned vinyl resins; and graft polymers obtained by polymerizing vinyl monomers in the presence of these. These resins may be used individually or in combination of two or more types.

[0053] The resin is preferably a resin having polar groups such as carboxyl groups, sulfonic acid groups, and hydroxyl groups, and in particular, it is preferably a resin having an acid value.

[0054] It is preferable to use an amorphous resin. However, a crystalline resin (for example, a crystalline polyester resin) may also be used. Here, amorphous resins refer to materials that, in thermal analysis measurements using differential scanning calorimetry (DSC), exhibit only a stepwise endothermic change rather than a clear endothermic peak, are solid at room temperature, and undergo thermoplasticization at temperatures above their glass transition temperature. On the other hand, crystalline resins are those that exhibit a clear endothermic peak in differential scanning calorimetry (DSC), rather than a stepwise change in endothermic heat. Specifically, for example, a crystalline resin means that the full width at half maximum (FWHM) of the endothermic peak measured at a heating rate of 10°C / min is within 10°C, while an amorphous resin means a resin whose FWHM exceeds 10°C, or a resin in which no clear endothermic peak is observed.

[0055] This section will explain amorphous resins. Examples of amorphous resins include known amorphous resins such as amorphous polyester resin, amorphous vinyl resin (e.g., styrene-acrylic resin), epoxy resin, polycarbonate resin, and polyurethane resin. Among these, amorphous polyester resin and amorphous vinyl resin (particularly styrene-acrylic resin) are preferred, and amorphous polyester resin is more preferred. Furthermore, it is also preferable to use amorphous polyester resin and styrene-acrylic resin in combination as the amorphous resin. In addition, it is also preferable to use an amorphous resin having amorphous polyester resin segments and styrene-acrylic resin segments as the amorphous resin.

[0056] Amorphous polyester resin Examples of amorphous polyester resins include condensation polymers of polycarboxylic acids and polyhydric alcohols. Commercially available amorphous polyester resins may be used, or synthesized ones may be used.

[0057] Examples of polycarboxylic acids include aliphatic dicarboxylic acids (e.g., oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, alkenylsuccinic acid, adipic acid, sebacic acid, etc.), alicyclic dicarboxylic acids (e.g., cyclohexanedicarboxylic acid, etc.), aromatic dicarboxylic acids (e.g., terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, etc.), their anhydrides, or their lower alkyl esters (e.g., with 1 to 5 carbon atoms). Among these, aromatic dicarboxylic acids are preferred as polycarboxylic acids. Polycarboxylic acids may be used in combination with dicarboxylic acids, or with trivalent or higher carboxylic acids that have a cross-linked or branched structure. Examples of trivalent or higher carboxylic acids include trimellitic acid, pyromellitic acid, their anhydrides, or their lower alkyl esters (e.g., having 1 to 5 carbon atoms). Polycarboxylic acids may be used individually or in combination of two or more.

[0058] 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, aromatic diols and alicyclic diols are preferred as polyhydric alcohols, with aromatic diols being more preferred. As for the polyhydric alcohol, a trihydric or higher polyhydric alcohol with a cross-linked or branched structure may be used in combination with the diol. Examples of trihydric or higher polyhydric alcohols include glycerin, trimethylolpropane, and pentaerythritol. Polyhydric alcohols may be used individually or in combination of two or more types.

[0059] Amorphous polyester resins can be obtained by known manufacturing methods. Specifically, for example, they can be obtained by a method in which the polymerization temperature is set to 180°C or higher and 230°C or lower, and the reaction system is subjected to reduced pressure as needed, while removing water and alcohol generated during condensation. If the monomers of the raw materials do not dissolve or become miscible at the reaction temperature, a high-boiling point solvent may be added as a solubilizer to dissolve them. In this case, the polycondensation reaction is carried out while distilling off the solubilizer. If there are monomers with poor miscibility in the copolymerization reaction, it is preferable to condense the poorly miscible monomers with the acid or alcohol to be polycondensed with them beforehand, and then polycondense them with the main component.

[0060] Let's explain the properties of the resin. The acid value of the resin is preferably 5 mg KOH / g or more and 40 mg KOH / g or less, more preferably 8 mg KOH / g or more and 20 mg KOH / g or less, and even more preferably 10 mg KOH / g or more and 16 mg KOH / g or less. In other words, it is preferable that the resin particles contain a resin with an acid value of 5 mg KOH / g or more and 40 mg KOH / g or less. Furthermore, the resin with an acid value of 5 mg KOH / g or more and 40 mg KOH / g or less is preferably a polyester resin. When a resin with an acid value within the above range (especially polyester resin) is used as the resin, excessive fusion of aggregated particles occurs during the fusion and coalescence process, making it easy for coarse particles to be generated. However, in this embodiment, even when a resin with an acid value within the above range (especially polyester resin) is used as the resin, the generation of coarse particles is easily suppressed. As a result, the generation of color spots is easily suppressed.

[0061] The acid value is determined by the neutralization titration method specified in JIS K0070 (1992). Specifically, it is as follows: An appropriate amount of sample was taken, 100 ml of solvent (diethyl ether / ethanol mixture) and a few drops of indicator (phenolphthalein solution) were added, and the mixture was thoroughly shaken on a water bath until the sample was completely dissolved. This was then titrated with a 0.1 mol / l potassium hydroxide ethanol solution, and the endpoint was defined as the point when the indicator turned a pale pink color for 30 seconds. The acid value was calculated as A = (B × f × 5.611) / S, where A is the acid value, S is the sample amount (g), B is the amount of 0.1 mol / l potassium hydroxide ethanol solution used for titration (ml), and f is the factor of the 0.1 mol / l potassium hydroxide ethanol solution.

[0062] The glass transition temperature (Tg) of the resin is preferably 50°C to 80°C, and more preferably 50°C to 65°C. The glass transition temperature was measured using a differential scanning calorimeter (MacScience: DSC3110, Thermal Analysis System 001) in accordance with JIS 7121-1987. The melting point of an indium-zinc mixture was used for temperature correction of the detector section of this instrument, and the heat of fusion of indium was used for heat quantity correction. The sample was placed in an aluminum pan, and the aluminum pan containing the sample was set up alongside an empty aluminum pan for control. Measurement was performed at a heating rate of 10°C / min. The glass transition temperature is defined as the temperature at the intersection of the baseline and the extension line of the rising edge in the endothermic region of the DSC curve obtained by measurement.

[0063] The weight-average molecular weight (Mw) of the resin is preferably 5,000 to 1,000,000, and more preferably 7,000 to 500,000. The number-average molecular weight (Mn) of the resin is preferably between 2,000 and 100,000. The molecular weight distribution (Mw / Mn) of the resin is preferably 1.5 to 100, and more preferably 2 to 60. The weight-average molecular weight and number-average molecular weight are measured by gel permeation chromatography (GPC). GPC molecular weight measurement is performed using a Tosoh GPC-HLC-8120GPC analyzer, a Tosoh TSKgel SuperHM-M (15cm) column, and THF solvent. The weight-average molecular weight and number-average molecular weight are calculated from these measurement results using a molecular weight calibration curve prepared with monodisperse polystyrene standard samples.

[0064] There are no particular restrictions on the amount of resin used; however, it should be selected appropriately depending on the solid content concentration of the resulting resin particle dispersion.

[0065] Neutralizing agent Examples of volatile bases used as neutralizing agents include basic compounds that can neutralize polar groups such as carboxyl groups, sulfonic acid groups, and hydroxyl groups in resins. Specifically, examples of bases include low-boiling point organic bases. Examples of low-boiling point organic bases include ammonia, methylamine, dimethylamine, trimethylamine, ethylamine, aziridine, azetidine, oxazole, pyrrolidine, oxadiazole, isoxazole, and oxazoline. Non-volatile bases include high-boiling-point organic bases and inorganic alkalis. Examples of high-boiling point organic bases include triethanolamine, diethanolamine, N-methyldiethanolamine, and dimethylethanolamine. Examples of inorganic alkalis include alkali metal hydroxides (e.g., sodium hydroxide, lithium hydroxide, potassium hydroxide, etc.), carbonates (e.g., sodium carbonate, sodium bicarbonate, etc.), and ammonia. As a neutralizing agent, it is preferable to use amines, which are weak bases, to prevent hydrolysis of the resin, and ammonia is more preferable. Furthermore, it is particularly preferable to add ammonia in the form of an aqueous solution.

[0066] The neutralization rate of the resin by the neutralizing agent is 60% or more and less than 150%, but from the viewpoint of improving the yield rate and narrowing the particle size distribution, 60% or more and less than 145% is more preferable, and 65% or more and 140% or less is even more preferable. In other words, the neutralizing agent is used so that the neutralization rate of the resin falls within the above range.

[0067] The neutralization rate of the resin is measured as follows: When the acid value of the resin is AV [mg-KOH / g-resin], the valence of the neutralization rate (i.e., the basic substance) to be added is n, the molecular weight of the neutralizing agent (i.e., the basic substance) to be added is Mwb, and the amount of neutralizing agent (i.e., the basic substance) added per gram of resin is mb [g], the calculation is expressed by the following formula. Resin neutralization rate [%] = mb × n × 56.1 ÷ Mwb ÷ AV × 1000

[0068] • Organic solvents Examples of organic solvents include well-known solvents used in phase inversion emulsification. Among these, from the viewpoint of improving the solubility of the resin, it is preferable that the organic solvent includes one or more organic solvents selected from the group consisting of esters and ketones, and one or more organic solvents selected from alcohols.

[0069] Examples of esters include ethyl acetate, butyl acetate, propyl acetate, and isopropyl acetate. Examples of ketones include acetone, methyl ethyl ketone, cyclohexanone, butanone, and methyl isobutyl ketone. Examples of alcohols include methanol, ethanol, isopropyl alcohol, n-propanol, n-butanol, diacetone alcohol, and 2-ethylhexanol.

[0070] ·Water medium As a water medium, for example, water (distilled water, deionized water, etc.) can be used. The amount of aqueous medium added to the oil phase medium in which the resin is dissolved in an organic solvent is, for example, an amount that causes phase inversion emulsification and reduces the amount of waste generated. Specifically, the amount of aqueous medium added is preferably 50% by mass or more and 2000% by mass or less, relative to the weight of the resin, and more preferably 100% by mass or more and 1000% by mass or less.

[0071] -Characteristics of resin particle dispersion- The volume-average particle size of the resin particles in the resin particle dispersion is preferably 0.01 μm or more and 1 μm or less, more preferably 0.08 μm or more and 0.8 μm or less, and even more preferably 0.1 μm or more and 0.6 μm or less. The volume-average particle size of the resin particles is measured using a laser diffraction particle size distribution analyzer (e.g., LA-700, manufactured by Horiba, Ltd.). The particle size distribution is obtained by subtracting the cumulative distribution from the smallest particle size side for each divided particle size range (channel), and the particle size that accounts for 50% of the total particle size is measured as the volume-average particle size D50v. The volume-average particle size of particles in other dispersions is measured in the same manner.

[0072] The solid content concentration of the resin particle dispersion can be selected as appropriate, but is preferably 1% by mass or more and 60% by mass or less, more preferably 5% by mass or more and 50% by mass or less, and particularly preferably 10% by mass or more and 50% by mass or less.

[0073] -Coloring agent particle dispersion- A colorant particle dispersion is, for example, a dispersion in which a colorant is dispersed in at least an aqueous medium. Examples of colorants include carbon black, chrome yellow, Hansa yellow, benzidine yellow, surene 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, risole red, rhodamine B lake, lake red C, pigment red, rose bengal, aniline blue, and ultramarine. Examples include various pigments such as phosphorus blue, chalcioyl blue, methylene blue chloride, phthalocyanine blue, pigment blue, phthalocyanine green, and malachite green oxalate, as well as various dyes such as acridine, xanthene, azo, benzoquinone, azine, anthraquinone, thioindico, dioxazine, thiazine, azomethine, indico, phthalocyanine, aniline black, polymethine, triphenylmethane, diphenylmethane, and thiazole. Colorants may be used individually or in combination of two or more types.

[0074] The coloring agent is dispersed in an aqueous medium by known methods, but media-type dispersers such as rotary shear homogenizers, ball mills, sand mills, and attritors, and high-pressure opposing impact dispersers are preferably used. Alternatively, a polar ionic surfactant may be used to disperse the coloring agent in an aqueous medium using a homogenizer to prepare a dispersion of coloring agent particles.

[0075] The volume-average particle size of the coloring agent is preferably 1 μm or less, more preferably 0.5 μm or less, and particularly preferably 0.01 μm or more and 0.5 μm or less. Dispersants added to further stabilize the dispersion stability of colorants in aqueous media and to lower the energy of colorants in toner include rosin, rosin derivatives, coupling agents, and polymer dispersants.

[0076] -Release agent particle dispersion- A release agent particle dispersion is a dispersion in which a release agent is dispersed in at least an aqueous medium. Examples of release agents include hydrocarbon waxes; natural waxes such as carnauba wax, rice wax, and candelilla wax; synthetic or mineral / petroleum-based waxes such as montan wax; and ester waxes such as fatty acid esters and montanic acid esters. However, the release agents are not limited to these. The release agent may be used alone or in combination of two or more types. The melting temperature of the release agent is preferably 50°C to 110°C, and more preferably 60°C to 100°C. The melting temperature is determined from the DSC curve obtained by differential scanning calorimetry (DSC) using the "melting peak temperature" described in JIS K 7121-1987 "Method for determining the transition temperature of plastics".

[0077] The release agent is dispersed in an aqueous medium by known methods, but media-type dispersers such as rotary shear homogenizers, ball mills, sand mills, and attritors, and high-pressure opposing impact dispersers are preferably used. Alternatively, a polar ionic surfactant may be used as the release agent, and it may be dispersed in an aqueous solvent using a homogenizer to prepare a release agent particle dispersion. The volume-average particle size of the release agent particles is preferably 1 μm or less, and more preferably 0.01 μm or more and 1 μm or more.

[0078] (agglomeration process) In the aggregation process, for example, a resin particle dispersion is mixed with a coloring agent particle dispersion and a mold release agent particle dispersion. Then, in the mixed dispersion, the resin particles, colorant particles, and release agent particles are aggregated to form aggregated particles.

[0079] Here, the flocculation process is usually carried out in the fusion / combination tank used in the fusion / combination process described later. However, it may also be carried out in a different tank.

[0080] Specifically, in a mixed dispersion, resin particles, colorant particles, and release agent particles are heteroaggregated to form aggregated particles containing resin particles, colorant particles, and release agent particles, which have a diameter close to that of the target toner particles.

[0081] More specifically, for example, a flocculant is added to a mixed dispersion, the pH of the mixed dispersion is adjusted to be acidic (for example, pH 2 to 5), a dispersion stabilizer is added as needed, and then the mixture is heated to a temperature of the glass transition temperature of the resin particles (specifically, for example, above the glass transition temperature of the resin particles -30°C or below the glass transition temperature of -10°C) to flocce the particles dispersed in the mixed dispersion and form flocculated particles. In the flocculation process, for example, the mixed dispersion may be stirred in a rotary shear homogenizer, the flocculant may be added at room temperature (e.g., 25°C), the pH of the mixed dispersion may be adjusted to acidic (e.g., pH 2 to 5), a dispersion stabilizer may be added as needed, and then the heating described above may be performed.

[0082] Examples of flocculants include surfactants with opposite polarity to the surfactant used as a dispersant added to the mixed dispersion, inorganic metal salts, and metal complexes with a valency of 2 or higher. Among these, inorganic metal salts are preferred. 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, as well as inorganic metal salt polymers such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. In particular, metal salts with a valency of 2 or higher are preferred as flocculants, trivalent metal salts are more preferred, and trivalent inorganic aluminum salts are even more preferred. Examples of trivalent inorganic aluminum salts include aluminum chloride, aluminum sulfate, polyaluminum chloride, and polyaluminum hydroxide.

[0083] In the aggregation process, for example, aggregation is stopped when the diameter of the aggregated particles reaches a diameter close to the diameter of the target toner particles. To stop the aggregation, for example, an alkaline aqueous solution of the dispersion containing the aggregated particles is added to raise the pH of the dispersion containing the aggregated particles to between 7 and 9. As the alkaline aqueous solution, at least one selected from the group consisting of aqueous solutions of alkali metal hydroxides, aqueous solutions of alkaline earth metal hydroxides, and aqueous solutions of chelating agents that chelate flocculants is preferred.

[0084] Examples of aqueous solutions of alkali metal hydroxides or alkaline earth metal hydroxides include aqueous solutions of sodium hydroxide, potassium hydroxide, calcium hydroxide, and barium hydroxide, with aqueous solution of sodium hydroxide being preferred. Chelating agents are chemical substances that chelate flocculants. Examples of chelating agents include oxycarboxylic acids such as tartaric acid, citric acid, and gluconic acid; and aminocarboxylic acids such as iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), and ethylenediaminetetraacetic acid (EDTA).

[0085] Here, as an alkaline aqueous solution, an aqueous solution of an alkali metal hydroxide or an aqueous solution of an alkaline earth metal hydroxide, along with an aqueous solution of a volatile base (preferably an aqueous solution of ammonium), may be added to the dispersion containing the agglomerated particles. Examples of bases to be added to the dispersion containing the agglomerated particles include organic bases and inorganic alkalis, as exemplified as neutralizing agents.

[0086] (fusion / unification process) In the fusion and coalescence process, the aggregated particle dispersion, which contains a volatile base and dispersed aggregated particles, is heated in a fusion and coalescence tank to fuse and coalesce the aggregated particles. Furthermore, the fusion and unification process satisfies at least one of the above conditions (1) to (3). In particular, from the viewpoint of improving transfer efficiency and suppressing color spots, it is preferable that the fusion and unification process satisfies at least one of the following conditions (11) to (13). Condition (11): The fusion / combination tank has one or more openings at the top, and the total area ratio of the openings is 5 cm per unit volume of the aggregated particle dispersion. 2 / m 3 More than 8000cm 2 / m 3 The following applies: Condition (12): The aggregated particles are fused and combined in a fusion / combination tank under reduced pressure within the range of (atmospheric pressure - 50) kPa to (atmospheric pressure - 0.5) kPa. Condition (13): 5 L / (min·m) per unit volume of aggregated particle dispersion in the fusion / coalition tank. 3 ) or more 150L / (min m 3 The aggregated particles are fused and combined while a gas at the following airflow rate is blown into the fusion / combination tank.

[0087] -Condition (1)- Under condition (1), for example, the fusion and fusion process is carried out using the fusion and fusion tank shown in Figure 1. Here, Figure 1 is a schematic diagram showing an example of a fusion / combination tank used in the toner manufacturing method according to this embodiment. Figure 1(A) is a schematic top view of the fusion / combination tank, and Figure 1(B) is a schematic front cross-sectional view.

[0088] The fusion / combination tank shown in Figure 1 comprises a storage tank 102 that contains the agglomerated particle dispersion 100 and has an opening 102A at the top, a stirrer 104 that stirs the agglomerated particle dispersion 100 contained in the storage tank 102, and a jacket 106 that heats the agglomerated particle dispersion 100 contained in the storage tank 102 from the outside surface of the storage tank.

[0089] In the fusion and unification tank shown in Figure 1, the aggregated particle dispersion 100 contained in the containment tank 102 is heated in the jacket 106 while being stirred by the agitator 104, causing the aggregated particles to fuse and unify. During the fusion and unification process, volatile bases are discharged from the tank system through an opening 102A located at the top of the containment tank 102.

[0090] In a fusion / unification process that satisfies condition (1), the total area ratio of the openings 102A is 5 cm² per unit volume of the aggregated particle dispersion 100. 2 / m 3 That's all, but 5cm 2 / m 3 More than 8000cm 2 / m 3 The following is preferable, 100cm 2 / m 3 More than 500cm 2 / m 3 The following are preferable. Increasing the total area ratio of the openings makes it easier for volatile bases to be discharged outside the tank system during the fusion and coalescence process. However, if the total area ratio of the openings 102A is increased too much, the water in the aggregated particle dispersion will evaporate more easily during the fusion and coalescence process, and in particular, more deposits will adhere to the tank walls of the fusion and coalescence tank. When these deposits peel off, coarse particles are more likely to be generated. Therefore, the total area ratio of openings 102A should be within the above range.

[0091] The number of openings 102A is preferably 2 to 30, more preferably 3 to 20, and even more preferably 3 to 10. A large number of openings 102A makes it easier for volatile bases to be discharged outside the tank system during the fusion and coalescence process. However, if there are too many openings 102A, the water in the aggregated particle dispersion will evaporate more easily during the fusion and coalescence process, and in particular, more deposits will adhere to the tank walls of the fusion and coalescence tank. When these deposits peel off, coarse particles are more likely to be generated. Therefore, the number of openings 102A should be within the above range.

[0092] -Condition (2)- Under condition (2), for example, the fusion and fusion process is carried out using the fusion and fusion tank shown in Figure 2. Here, Figure 2 is a schematic diagram showing another example of a fusion / combination tank used in the toner manufacturing method according to this embodiment.

[0093] The fusion / integration tank shown in Figure 2 comprises a containment tank 102 for containing the agglomerated particle dispersion 100, a stirrer 104 for stirring the agglomerated particle dispersion 100 contained in the containment tank 102, and a jacket 106 for heating the agglomerated particle dispersion 100 contained in the containment tank 102 from the outside surface. An air inlet pipe 120 and an air outlet pipe 122 are connected to the upper part of the containment tank 102. A pressure regulating valve 120A is provided in the path of the air inlet pipe 120. A pressure regulating valve 122A is provided in the path of the air discharge pipe 122. A suction device 124 is provided on the air outlet side of the air discharge pipe 122.

[0094] In the fusion and unification tank shown in Figure 2, the agglomerated particle dispersion 100 contained in the containment tank 102 is stirred by the agitator 104 and heated by the jacket 106 to fuse and unify the agglomerated particles. Then, the suction device 124 is activated, and the air flowing through the air inlet pipe 120 and the air outlet pipe 122 is regulated by the pressure regulating valve 122A, thereby reducing the pressure in the containment tank 102. This discharges the volatile base out of the tank system.

[0095] In the fusion and unification process that satisfies condition (2), the reduced pressure in the fusion and unification tank is in the range of (atmospheric pressure - 0.5) kPa or less, but is preferably in the range of (atmospheric pressure - 50) kPa or more and (atmospheric pressure - 0.5) kPa or less, and more preferably in the range of (atmospheric pressure - 40) kPa or more and (atmospheric pressure - 1.0) kPa or less. Increasing the reduced pressure inside the fusion / combination tank makes it easier for volatile bases to be discharged outside the tank system during the fusion / combination process. However, if the reduced pressure inside the fusion / combination tank is increased too much, the water in the aggregated particle dispersion will evaporate more easily during the fusion / combination process, and in particular, more deposits will adhere to the tank walls of the fusion / combination tank. When these deposits peel off, coarse particles are more likely to be generated. Therefore, the reduced pressure in the fusion / combination tank should be within the above range.

[0096] -Condition (3)- Under condition (3), for example, the fusion and fusion process is carried out using the fusion and fusion tank shown in Figure 3. Here, Figure 3 is a schematic diagram showing another example of a fusion / combination tank used in the toner manufacturing method according to this embodiment.

[0097] The fusion / integration tank shown in Figure 3 comprises a containment tank 102 for containing the agglomerated particle dispersion 100, a stirrer 104 for stirring the agglomerated particle dispersion 100 contained in the containment tank 102, and a jacket 106 for heating the agglomerated particle dispersion 100 contained in the containment tank 102 from the outside surface. An air inlet pipe 130 and an air outlet pipe 132 are connected to the upper part of the containment tank 102. A blower 134 is provided on the air inlet side of the air intake pipe 130.

[0098] In the fusion and unification tank shown in Figure 3, the agglomerated particle dispersion 100 contained in the containment tank 102 is heated in the jacket 106 while being stirred by the agitator 104, thereby fusing and unifying the agglomerated particles. Then, the blower 134 is driven to introduce gas into the containment tank 102 from the air inlet pipe 130 and discharge it from the air outlet pipe 132, thereby blowing gas into the containment tank 102. In this way, the volatile base is discharged outside the tank system.

[0099] In the fusion / combination process that satisfies condition (3), the gas flow rate is 5 L / (min·m) per unit volume of the aggregated particle dispersion liquid in the fusion / combination tank. 3 ) or more, but 5L / (min·m 3) or more 150L / (min m 3 Preferably less than 10 L / (min·m 3 ) or more 130L / (min m 3 The following are preferable. Increasing the gas flow rate makes it easier for volatile bases to be discharged outside the tank system during the fusion and coalescence process. However, if the gas flow rate is increased too much, the water in the aggregated particle dispersion will evaporate more easily during the fusion and coalescence process, leading to an increase in deposits, especially on the tank walls of the fusion and coalescence tank. When these deposits detach, coarse particles are more likely to be generated. Therefore, the airflow rate of the gas should be within the above range.

[0100] -Base weight- In the fusion / unification process, the amount of base is reduced, for example, as follows, by satisfying at least one of the above conditions (1) to (3).

[0101] In the fusion and unification process, the amount of volatile base in the agglomerated particle dispersion when the agglomerated particle dispersion reaches the fusion and unification temperature is 10% by mass or more and 98% by mass or less, relative to the amount of volatile base in the agglomerated particle dispersion at the start of heating of the agglomerated particle dispersion. Preferably, the amount of base is 10% by mass or more and 98% by mass or less. Reducing the amount of base promotes the fusion and coalescence of aggregated particles, shortening the fusion and coalescence time and suppressing the decrease in transfer efficiency caused by residual decomposition components of the resin. However, if the amount of base is reduced too much, the fusion and coalescence of aggregated particles will be excessively promoted, making it easier for coarse particles to be generated. Therefore, the reduction rate of the base amount shall be within the above range.

[0102] In the fusion and merging process, the amount of volatile base in the aggregated particle dispersion at the start of heating of the aggregated particle dispersion is preferably 0.005% by mass or more and 1.0% by mass or less, relative to the solid content of the aggregated particle dispersion, and more preferably 0.01% by mass or more and 0.5% by mass or less. If the amount of base in the agglomerated particle dispersion is low at the start of heating, the fusion and coalescence of the agglomerated particles will be excessively promoted, making it easier for coarse particles to form. However, if the amount of base in the agglomerated particle dispersion is too low at the start of heating, the fusion and coalescence of the agglomerated particles will be excessively promoted, making it easier for coarse particles to form. Therefore, the amount of base in the aggregated particle dispersion at the start of heating of the aggregated particle dispersion shall be within the above range.

[0103] Here, the amount of base is measured as follows: Using an ICS-2000 ion chromatograph manufactured by Nippon Dionex Co., Ltd., the content of volatile base components was analyzed under the following conditions: A 1.00 g sample of the aggregated particle dispersion was extracted using a filter (HP020AN manufactured by Advantec Co., Ltd.), and the cation analysis was performed using an ion chromatograph to measure the content of volatile bases. (Ion chromatography measurement conditions) Cation separation column: IonPacCS12A, manufactured by Nippon Dionex Co., Ltd. Cation guard column: IonPacCG12A, manufactured by Nippon Dionex Co., Ltd. Eluent: Methanesulfonic acid 20 mM Flow rate: 1ml / min Temperature: 30℃ Detection method: The base content measured by the electrical conductivity method (suppressor type) was divided by the mass of solids in 1.00 g of the agglutinated particle dispersion. This value, expressed as a percentage, was defined as the amount of base (mass %) relative to the solids of the agglutinated particle dispersion.

[0104] In the fusion and unification process, the pH of the agglomerated particle dispersion at the start of heating is 6.5 to 9.5 (preferably 7.0 to 9.0), and the pH of the agglomerated particle dispersion when the fusion and unification temperature is reached is 6 to 9 (preferably 6.5 to 8.5). By keeping the pH of the aggregated particle dispersion at the start of heating and the pH of the aggregated particle dispersion at the time the fusion / unification temperature is reached within the above range, and by controlling the rate of reduction of the amount of base within the above range, it is possible to shorten the fusion / unification time while reducing excessive promotion of fusion / unification of aggregated particles.

[0105] -Other conditions- In the fusion and coalescence process, it is preferable to add a mixed aqueous solution of acid and surfactant to the aggregated particle dispersion that has reached a temperature of (the glass transition temperature Tg of the resin particles) or (the glass transition temperature Tg + 50°C). When adding a mixed aqueous solution of acid and surfactant, the temperature of the aggregated particle dispersion is more preferably between (glass transition temperature Tg + 5°C) and (glass transition temperature Tg + 40°C), and even more preferably between (glass transition temperature Tg + 10°C) and (glass transition temperature Tg + 35°C).

[0106] When adding a mixed aqueous solution of acid and surfactant, if the temperature of the agglomerated particle dispersion is above (the glass transition temperature Tg of the resin particles + 5°C), the fusion and coalescence of the agglomerated particles is promoted, shortening the fusion and coalescence time and suppressing the decrease in transfer efficiency caused by the residue of decomposed resin components. However, if the temperature of the agglomerated particle dispersion is too high when adding the mixed aqueous solution of acid and surfactant, the fusion and coalescence of the agglomerated particles will be excessively promoted, making it easier for coarse particles to be generated. Therefore, when adding a mixed aqueous solution of acid and surfactant, the temperature of the aggregated particle dispersion should be within the above range.

[0107] Here, the mixed aqueous solution of acid and surfactant is preferably added to the agglomerated particle dispersion after heating it to a temperature within the above range, for example, after 10 minutes to 3 hours. This moderately promotes the fusion and coalescence of the agglomerated particles, shortens the fusion and coalescence time, and suppresses the generation of coarse particles.

[0108] Examples of acids include nitric acid, sulfuric acid, hydrochloric acid, acetic acid, phosphoric acid, carbonic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, citric acid, malic acid, trimellitic acid, acrylic acid, methacrylic acid, maleic acid, and cinnamic acid. Acids may be used individually or in combination of two or more. Among these, at least one acid selected from the group consisting of nitric acid, sulfuric acid, hydrochloric acid, and acetic acid is preferred.

[0109] Examples of surfactants include various types of surfactants such as anionic surfactants, amphoteric surfactants, cationic surfactants, and nonionic surfactants. Among these, anionic surfactants are preferred as surfactants from the viewpoint of improving the storage stability of resin particle dispersions.

[0110] Examples of anionic surfactants include carboxylic acid type, sulfate ester type, sulfonic acid type, and phosphate ester type anionic surfactants. Examples of anionic surfactants include fatty acid salts, rosinates, naphthenates, ether carboxylates, alkenyl succinates, monoalkyl sulfates, dialkyl sulfates, alkyl polyoxyethylene sulfates, alkylphenyl polyoxyethylene sulfates, monoacylglycerin sulfates, acylaminosulfate salts, sulfated oils, sulfated fatty acid alkyl esters, α-olefin sulfons, derial alkanesulfons, α-sulfo fatty acid salts, acyl isethionates, dialkyl sulfosuccinates, alkylbenzene sulfons, alkylnaphthalene sulfons, alkyldiphenyl ether disulfonates, petroleum sulfons, lignin sulfons, alkyl phosphates, alkyl polyoxyethylene phosphates, alkylphenyl polyoxyethylene phosphates, perfluoroalkyl carboxylates, perfluoroalkyl sulfons, and perfluoroalkyl phosphates.

[0111] Among these, from the viewpoint of improving the dispersion stability of the toner particles formed, anionic surfactants of the sulfate ester type or sulfonic acid type are more preferred, and sulfonic acid type anionic surfactants are particularly preferred.

[0112] In a mixed aqueous solution, the ratio A1 / B1 of the molar amount of acid A1 to the molar amount of surfactant is preferably 0.5 to 2.0, more preferably 0.7 to 1.8, and even more preferably 0.8 to 1.5, from the viewpoint of easily suppressing the aggregation of aggregated particles.

[0113] There are no restrictions on the method of adding acid and surfactant to a dispersion containing aggregated particles. The acid and surfactant may be added separately, simultaneously, or sequentially to the dispersion containing aggregated particles. From the viewpoint of easily suppressing the aggregation of aggregated particles, it is preferable to add a mixture of acid and surfactant, which has been mixed in advance, to the dispersion containing the aggregated particles. A mixture of acid and surfactant is, for example, an aqueous solution or aqueous dispersion using water as a solvent or dispersion medium. The total mass of the acid and surfactant in the total mass of the mixture (for example, an aqueous solution or aqueous dispersion) is preferably 1% to 10% by mass, more preferably 2% to 8% by mass, and even more preferably 3% to 6% by mass, from the viewpoint of efficiency in exhibiting the effect and stability of the active ingredients in the mixture.

[0114] In the fusion and unification process, the heating rate from the start of heating of the aggregated particle dispersion to the fusion and unification temperature is preferably 0.05°C / min or more and 1°C / min or less, more preferably 0.1°C / min or more and 0.5°C / min or less, and even more preferably 0.1°C / min or more and 0.5°C / min or less. Increasing the heating rate makes it easier for volatile bases to be discharged outside the tank system during the fusion and coalescence process. However, if the heating rate is increased too much, the temperature of the heat source required for heating will rise, causing the temperature of the aggregated particle dispersion near the heat source (temperature control jacket and heat transfer coil) to rise locally, making it easier for coarse particles to form. Therefore, the airflow rate of the gas should be within the above range.

[0115] The fusion and coalescence process involves, for example, fusing and coalescing the aggregated particles while stirring the aggregated particle dispersion in a fusion and coalescence tank. Furthermore, in the agglomerated particle dispersion liquid being stirred, the ratio (H / D) of the difference H between the liquid level at the wall of the fusion / combination tank and the liquid level at the stirring axis to the radius D of the fusion / combination tank (see Figure 1) is preferably 0.01 or more and 2 or less, more preferably 0.05 or more and 1 or less, and even more preferably 0.1 or more and 0.5 or less. When the ratio (H / D) is large, that is, when the difference H between the liquid level at the wall of the fusion / combination tank and the liquid level at the stirring shaft is large, the exposed area of ​​the liquid surface of the agglomerated particle dispersion increases, making it easier for volatile bases to be discharged outside the tank system during the fusion / combination process. However, if the ratio (H / D) is too large, coarse particles are more likely to be generated. The reason for this is not clear, but when the ratio (H / D) is too large, the amount of air entrained into the agglomerated particle dispersion by stirring increases, and a large amount of fine bubbles are generated in the agglomerated particle dispersion. At that time, the surfactant micelles on the surface of the bubbles, and the amount of surfactant that contributes to the stabilization of the agglomerated particles decreases, causing the agglomerated particles to fuse together and become coarse particles, making it easier for coarse particles to be generated. Therefore, the ratio (H / D) should be within the above range.

[0116] Here, the radius D of the fusion / unification tank is preferably 100 mm or more and 3000 mm or less, and more preferably 500 mm or more and 2000 mm or less. Note that the radius D of the fusion / combination tank represents the radius at the liquid surface along the stirring axis (see Figure 1). Furthermore, the liquid level height at the stirring shaft indicates the distance from the bottom of the fusion / unification tank (i.e., the containment tank) to the liquid level of the dispersed aggregated particles, as measured by the stirring shaft of the agitator (see Figure 1).

[0117] Toner particles are obtained through the above process. Furthermore, toner particles may be manufactured by further mixing a dispersion of aggregated particles containing dispersed aggregated particles with a dispersion of resin particles containing dispersed resin particles, thereby agglomerating the aggregated particles so that resin particles adhere to the surface of the aggregated particles to form second aggregated particles, and by heating the second dispersion of aggregated particles containing the second aggregated particles to fuse and combine the second aggregated particles to form toner particles with a core / shell structure.

[0118] After the fusion and combination process is complete, the toner particles formed in the solution are subjected to known washing, solid-liquid separation, and drying processes to obtain dried toner particles. The washing process should be thoroughly performed using ion-exchanged water for displacement washing, considering the electrostatic charge. The solid-liquid separation process is not particularly restricted, but suction filtration, pressure filtration, etc., are preferable for productivity. The drying process is also not particularly restricted, but freeze-drying, air-flow drying, fluidized bed drying, vibratory fluidized bed drying, etc., are preferable for productivity.

[0119] The toner manufacturing method according to this embodiment is, for example, manufactured by adding an external additive to the obtained dried toner particles and mixing them. Mixing can be performed using, for example, a V-blender, a Henschel mixer, a Redigge mixer, etc. Furthermore, if necessary, coarse particles of toner may be removed using a vibrating screen separator, a wind screen separator, etc.

[0120] Examples of external additives include inorganic particles. Examples of such inorganic particles include SiO2, TiO2, Al2O3, CuO, ZnO, SnO2, CeO2, Fe2O3, MgO, BaO, CaO, K2O, Na2O, ZrO2, CaO·SiO2, K2O·(TiO2)n, Al2O3·2SiO2, CaCO3, MgCO3, BaSO4, MgSO4, and the like.

[0121] The surface of the inorganic particles used as an external additive should preferably be hydrophobic. Hydrophobic treatment is carried out, for example, by immersing the inorganic particles in a hydrophobic agent. The hydrophobic agent is not particularly limited, but examples include silane-based coupling agents, silicone oil, titanate-based coupling agents, and aluminum-based coupling agents. These may be used individually or in combination of two or more. The amount of hydrophobic treatment agent is typically, for example, 1 to 10 parts by mass per 100 parts by mass of inorganic particles.

[0122] Examples of external additives include resin particles (such as polystyrene, polymethyl methacrylate (PMMA), and melamine resin), and cleaning activators (for example, metal salts of higher fatty acids represented by zinc stearate, and fluorine-based high molecular weight particles).

[0123] The amount of external additive added is preferably 0.01% by mass or more and 5% by mass or less relative to the toner particles, and more preferably 0.01% by mass or more and 2.0% by mass or less.

[0124] -Toner Characteristics- In the toner manufacturing method according to this embodiment, the toner particles obtained may be single-layer toner particles, or may be toner particles with a so-called core-shell structure consisting of a core (core particle) and a coating layer (shell layer) covering the core. Here, the core-shell structure of the toner particles may consist of, for example, a core portion comprising a binder resin and, if necessary, other additives such as a colorant and a release agent, and a coating layer comprising a binder resin.

[0125] 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.

[0126] The average particle size and particle size distribution indices of the toner particles are measured using the Coulter Multisizer II (manufactured by Beckman Coulter), and the electrolyte is measured using the ISOTON-II (manufactured by Beckman Coulter). For measurement, add 0.5 mg to 50 mg of the sample to be measured in 2 ml of a 5% aqueous solution of a surfactant (preferably sodium alkylbenzenesulfonate) as a dispersant. Add this to 100 ml to 150 ml of electrolyte. The electrolyte containing the suspended sample is dispersed in an ultrasonic disperser for 1 minute. The particle size distribution of particles with a diameter of 2 μm to 60 μm is then measured using a Coulter Multisizer II with an aperture diameter of 100 μm. The number of particles sampled is 50,000. Based on the measured particle size distribution, a cumulative distribution of volume and number is drawn for each divided particle size range (channel) from the smallest diameter side. The particle size at which the cumulative total reaches 16% is defined as the volume particle size D16v and the number particle size D16p, the particle size at which the cumulative total reaches 50% is defined as the volume average particle size D50v and the cumulative number average particle size D50p, and the particle size at which the cumulative total reaches 84% ​​is defined as the volume particle size D84v and the number particle size D84p. Using these, the volume particle size distribution index (GSDv) is (D84v / D16v) 1 / 2 The GSDp index is (D84p / D16p) 1 / 2 It is calculated as follows.

[0127] The average circularity of the toner particles is preferably 0.94 to 1.00, and more preferably 0.95 to 0.98.

[0128] The average circularity of toner particles is determined by (circular equivalent perimeter) / (perimeter) [(perimeter of a circle with the same projected area as the particle image) / (perimeter of the particle projection image)]. Specifically, it is a value measured by the following method. First, the toner particles to be measured are collected by suction, a flattened flow is formed, and a still image of the particles is captured by instantaneous strobe flashing. This particle image is then analyzed using a flow-type particle image analyzer (FPIA-3000 manufactured by Sysmex Corporation). The number of samples used to determine the average circularity is 3500. If the toner contains external additives, the toner 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. [Examples]

[0129] The following describes embodiments of the present invention, but the present invention is not limited to these embodiments. In the following description, unless otherwise specified, "parts" and "%" all refer to mass.

[0130] <Preparation of resin particle dispersion> (Preparation of polyester resin particle dispersion (1)) [Synthesis of polyester resin (1)] In a reaction vessel equipped with a stirrer, thermometer, condenser, and nitrogen gas inlet tube, 80 moles of polyoxypropylene (2,2)-2,2-bis(4-hydroxyphenyl)propane, 10 moles of ethylene glycol, 10 moles of cyclohexanediol, 80 moles of terephthalic acid, 10 moles of isophthalic acid, and 10 moles of n-dodecenylsuccinate were added, and the reaction vessel was purged with dry nitrogen gas. Subsequently, 0.25 parts by mass of titanium tetrabutoxide was added as a catalyst per 100 parts by mass of the monomer components. The reaction was stirred at 170°C for 3 hours under a nitrogen gas stream, then the temperature was further increased to 210°C over 1 hour, the pressure in the reaction vessel was reduced to 3 kPa, and the reaction was stirred under reduced pressure for 13 hours to obtain polyester resin (1). The glass transition temperature of the obtained resin was measured using a differential scanning calorimeter (DSC) and was found to be 45°C. Furthermore, the acid value was 15 mg KOH / g.

[0131] [Preparation of polyester resin particle dispersion] Next, 200 parts by mass of polyester resin, 100 parts by mass of methyl ethyl ketone, and 70 parts by mass of isopropyl alcohol were placed in a 3-liter jacketed reaction vessel (Tokyo Rikakikai Co., Ltd.: BJ-30N) equipped with a condenser, thermometer, water dropper, and anchor vanes. The resin was dissolved while stirring at 100 rpm in a water-circulating constant temperature bath while maintaining the temperature at 70°C. Then, the stirring speed was increased to 150 rpm, the water-circulating constant temperature bath was set to 66°C, and 10 parts of 10% aqueous ammonia (reagent) were added over 10 minutes. After that, 600 parts by mass of deionized water, which had been kept at 66°C, were added dropwise at a rate of 5 parts by mass / minute to invert the phase and obtain an emulsion. 600 parts of the obtained emulsion and 525 parts by mass of deionized water were placed in a 2-liter round-bottom flask and set in an evaporator (Tokyo Rikakikai Co., Ltd.) equipped with a vacuum control unit via a trap bulb. The round-bottom flask was heated in a 60°C water bath while rotating, and the pressure was reduced to 7 kPa while taking care to prevent bumping, to remove the solvent. When the amount of recovered solvent reached 825 parts, the pressure was returned to atmospheric pressure, and the round-bottom flask was cooled with water to obtain the dispersion. Deionized water was added to obtain a polyester resin particle dispersion (1) with a solid content of 20% by mass.

[0132] (Preparation of polyester resin particle dispersion (2)) In the synthesis of the polyester resin, 0.08 parts by mass of titanium tetrabutoxide was added as a catalyst per 100 parts by mass of the monomer component. The reaction was carried out with stirring at 170°C for 8 hours under a nitrogen gas stream, then the temperature was further increased to 210°C over 1 hour, the pressure in the reaction vessel was reduced to 3 kPa, and the reaction was carried out with stirring under reduced pressure for 36 hours to obtain polyester resin (2). The glass transition temperature of the obtained resin was measured using a differential scanning calorimeter (DSC) and was found to be 65°C. The acid value was 3 mg KOH / g. Polyester resin particle dispersion (2) was obtained in the same manner as polyester resin particle dispersion (1).

[0133] (Preparation of polyester resin particle dispersion (3)) In the synthesis of the polyester resin, 0.1 parts by mass of titanium tetrabutoxide was added as a catalyst to 100 parts by mass of the monomer component. The reaction was carried out with stirring at 170°C for 6 hours under a nitrogen gas stream, then the temperature was further increased to 210°C over 1 hour, the pressure in the reaction vessel was reduced to 3 kPa, and the reaction was carried out with stirring under reduced pressure for 30 hours to obtain polyester resin (3). The glass transition temperature of the obtained resin was measured using a differential scanning calorimeter (DSC) and was found to be 58°C. The acid value was 5 mg KOH / g. Polyester resin particle dispersion (3) was obtained in the same manner as polyester resin particle dispersion (1).

[0134] (Preparation of polyester resin particle dispersion (4)) In the synthesis of the polyester resin, 0.6 parts by mass of titanium tetrabutoxide was added as a catalyst to 100 parts by mass of the monomer component. The reaction was carried out with stirring at 170°C for 3 hours under a nitrogen gas stream, then the temperature was further increased to 210°C over 1 hour, the pressure in the reaction vessel was reduced to 3 kPa, and the reaction was carried out with stirring under reduced pressure for 10 hours to obtain polyester resin (3). The glass transition temperature of the obtained resin was measured using a differential scanning calorimeter (DSC) and was found to be 42°C. The acid value was 40 mg KOH / g. Polyester resin particle dispersion (4) was obtained in the same manner as polyester resin particle dispersion (1).

[0135] (Preparation of polyester resin particle dispersion (5)) In the synthesis of the polyester resin, 0.7 parts by mass of titanium tetrabutoxide was added as a catalyst to 100 parts by mass of the monomer component. The reaction was carried out with stirring at 170°C for 3 hours under a nitrogen gas stream, then the temperature was further increased to 210°C over 1 hour, the pressure in the reaction vessel was reduced to 3 kPa, and the reaction was carried out with stirring under reduced pressure for 10 hours to obtain polyester resin (4). The glass transition temperature of the obtained resin was measured using a differential scanning calorimeter (DSC) and was found to be 40°C. The acid value was 45 mg KOH / g. Polyester resin particle dispersion (5) was obtained in the same manner as polyester resin particle dispersion (1).

[0136] (Preparation of polyester resin particle dispersion (6)) Polyester resin particle dispersion (6) was obtained in the same manner as polyester resin particle dispersion (1), except that 5.0 parts of 40% methylamine aqueous solution (reagent) were used instead of 10 parts of 10% aqueous ammonia (reagent) in the preparation of the polyester resin particle dispersion (1).

[0137] <Preparation of a dispersion of coloring agent particles> • Cyanide pigment (manufactured by Dainichi Seika Co., Ltd., Pigment Blue 15:3 (copper phthalocyanine)): 98 parts Anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Neogen®): 2 parts • Ion-exchanged water: 400 bottles The above ingredients were mixed and dissolved, and dispersed for 10 minutes using a homogenizer (IKA Ultra-Turrax) to obtain a dispersion of colorant particles with a central particle size of 0.16 μm and a solid content of 20%.

[0138] <Preparation of mold release agent particle dispersion> Paraffin wax (manufactured by Nippon Seiro Co., Ltd., FNP92, endothermic peak onset 81℃): 45 parts • Anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK): 5 parts • Ion-exchanged water: 200 bottles The above ingredients were mixed and heated to 95°C, then dispersed using a homogenizer (IKA, Ultra-Turrax T50). Subsequently, the mixture was dispersed using a Manton-Gorin high-pressure homogenizer (Gorin), and a release agent particle dispersion (solid content concentration: 20%) was prepared. The volume-average particle size of the release agent particles was 0.19 μm.

[0139] <Examples A1-A44, A46, Comparative Example A1> (Toner particle production) The following raw materials were added to the fusion / combination tank shown in Figure 1, and the coagulation and fusion / combination processes were carried out as follows. The fusion / combination process was carried out according to the conditions shown in Table 1.

[0140] -Agglomeration process- • Polyester resin particle dispersion (1): 100 parts by mass • Coloring agent particle dispersion: 10 parts by mass • Release agent particle dispersion: 9 parts by mass • Anionic surfactant (TaycaPower BN2060, manufactured by Tayca Co., Ltd.): 1 part by mass • Ion-exchanged water: 200 parts by mass The above raw materials were placed in a 2L cylindrical stainless steel container as a fusion / combination tank as shown in Figure 1, and 3 parts of 0.3M nitric acid aqueous solution were added to adjust the pH to 3.0. Next, while applying shear force at 6,000 rpm using Ultraturrax (manufactured by IKA Japan), 50 parts of a 10% aqueous solution of aluminum sulfate was added dropwise as a flocculant, and the mixture was stirred for 5 minutes. Next, the raw material mixture was heated to 45°C using a mantle heater and held for 30 minutes. Then, a coating resin particle dispersion, prepared by mixing 25 parts polyester resin dispersion and 10 parts deionized water and adjusting the pH to 3.0 beforehand, was added and held for 10 minutes. After that, in order to stop the growth of the coated aggregate particles, a 1M sodium hydroxide aqueous solution was added to control the pH of the raw material mixture to 8.0.

[0141] -Fusion / coalescence process- Next, in order to fuse and combine the aggregated particles, the temperature was increased at the rate shown in Table 1 until the temperature at which fusion and combination could be reached was reached. After reaching the fusion and unification temperature, the circularity was measured 30 minutes later and confirmed to be 0.93. Then, 6 parts of a mixed aqueous solution of 2% by mass nitric acid and 2% by mass surfactant (anionic surfactant (TaycaPower BN2060, manufactured by Tayca Co., Ltd.)) were added. The average circularity was then measured every 30 minutes and maintained until it reached 0.98. The time from reaching the fusion and unification temperature to the toner's circularity reaching 0.98 was 1 hour.

[0142] The mixture was then cooled to 20°C at a rate of 20°C / min. Within 60 minutes after cooling, the pH was adjusted to 9.5 using a 1N sodium hydroxide aqueous solution. After pH adjustment, the mixture was filtered, thoroughly washed with deionized water, and dried to obtain toner particles with a volume-average particle size of 5.9 μm and an average circularity of 0.98.

[0143] (Toner manufacturing) 100 parts of toner particles and 1.5 parts of hydrophobic silica (manufactured by Nippon Aerosil Co., Ltd., RY50) were mixed and mixed for 30 seconds at a rotation speed of 10,000 rpm using a sample mill. Then, the mixture was sieved using a wind-powered sieve separator, Highvolter 300 (manufactured by Shin Tokyo Kikai Co., Ltd., feed rate 600 kg / h, mesh opening 38 μm) to obtain toner.

[0144] (Manufacturing of developer) The obtained toner and the carrier described below were placed in a V-blender in a toner:carrier ratio of 5:95 (by mass) and stirred for 20 minutes to obtain a developer.

[0145] -Creating a Career- 100 parts of ferrite particles (manufactured by Powdertech 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, with a weight-average molecular weight of 5% or less) were placed in a pressurized kneader together with 500 parts of toluene. After stirring and mixing at room temperature for 15 minutes, the temperature was raised to 70°C while mixing under reduced pressure to distill off the toluene, and then the mixture was cooled and classified using a 105 μm sieve to obtain a resin-coated ferrite carrier.

[0146] <Example A45> Toner particles, toner, and developer were produced in the same manner as in Example (1), except that a 10% aqueous ammonia solution was used instead of a 1M aqueous sodium hydroxide solution in the agglomeration process to stop the growth of the coated agglomerated particles.

[0147] <Examples B1-B4, Comparative Example B1> The raw materials were introduced into the fusion / combination tank shown in Figure 2, and the coagulation and fusion / combination processes were carried out. The fusion / combination process was performed according to the conditions shown in Table 2. Otherwise, toner particles, toner, and developer were manufactured in the same manner as in Example A1.

[0148] <Examples C1-C4, Comparative Example C1> The raw materials were introduced into the fusion / combination tank shown in Figure 3, and the coagulation and fusion / combination processes were carried out. The fusion / combination process was performed according to the conditions shown in Table 3. Otherwise, toner particles, toner, and developer were manufactured in the same manner as in Example A1.

[0149] <Rating> (Color point evaluation) The developer obtained for each example was placed in the developing unit of a modified image forming apparatus, "ApeosPort-IV C5575 (manufactured by Fujifilm Business Innovation Co., Ltd.)" (a modified version with the automatic density control sensor for environmental fluctuations disabled). Using this modified image forming apparatus, 5000 images with an image density of Cin1% were continuously printed onto A4 paper under conditions of 10°C and 15% RH. Subsequently, 1000 images with an image density of Cin 80% were continuously printed onto A4 paper under conditions of 30°C and 85% RH. Finally, the presence or absence of color spots caused by electrostatic aggregation of toner particles was visually checked in the 1000 images that were printed, and the occurrence of color spots was classified as follows. A, B, and C are within the acceptable range. A: No color spots appearing. B: Color spots appear on 1 to 3 cards. C: Color dots appear on 3 to 5 cards. C-: Color dots appear on 6 to 8 cards. D: Color dots appear on 9 or more images

[0150] (Evaluation of transcription efficiency) The developer samples obtained were stored in a modified "700Digital Color Press" manufactured by Fujifilm Business Innovation Co., Ltd. Using this modified image forming apparatus, the toner load on the photoreceptor is 5g / m².2 The development potential was adjusted to achieve the desired result, and 1000 images with an image area ratio of 5% were continuously printed on A4-sized plain paper under low temperature and low humidity conditions (temperature 10°C / relative humidity 20%). Next, when printing one sheet, the device was stopped immediately after the toner image on the photoconductor moved to the intermediate transfer belt (i.e., before cleaning the photoconductor). The toner remaining on the photoconductor without being transferred was removed with mending tape and its weight was measured. The initial transfer efficiency was determined from the amount of toner applied during development and the amount of toner remaining, using the following formula (1), and evaluated according to the following criteria. A and B are within the acceptable range. Formula (1): Transfer efficiency = (Amount of toner applied during development - Amount of toner remaining) ÷ Amount of toner applied during development × 100 A: Transfer efficiency of 98% or higher B: Transfer efficiency of 95% or more, but less than 98% C: Transfer efficiency of 90% or more, but less than 95% C-: Transfer efficiency is 85% or higher, but less than 90%. D: Transcription efficiency is less than 85%

[0151] [Table 1-1]

[0152] [Table 1-2]

[0153] [Table 2]

[0154] [Table 3]

[0155] From the results above, it can be seen that this embodiment has higher transfer efficiency and suppresses color spots compared to the comparative example. [Explanation of Symbols]

[0156] 100 Agglomerated particle dispersion 102 Storage Tank 102A opening 104 Agitator 106 Jacket 120 Air inlet pipe 120A Pressure Regulating Valve 122 Air exhaust pipe 122A Pressure Regulating Valve 124 Suction machine 130 Air intake pipe 132 Air exhaust pipe 134 Blower

Claims

1. A step of agglomerating at least the resin particles in a dispersion containing resin particles to form aggregated particles, A process of heating the aggregated particle dispersion, which contains a volatile base and the aggregated particles, in a fusion / combination tank, thereby fusing and combining the aggregated particles, It has, A method for manufacturing electrostatic image developing toner, wherein the step of fusing and unifying the aggregated particles satisfies at least one of the following conditions (1) to (3). Condition (1): The upper part of the fusion / combination tank has multiple openings leading to the outside of the fusion / combination tank system, and the total area ratio of the openings is 5 cm per unit volume of the aggregated particle dispersion. ２ / m ３ That's all. Condition (2): The aggregated particles are fused and combined in the fusion / combination tank under reduced pressure to a range of (atmospheric pressure - 0.5) kPa or less. Condition (3): The step of fusing and unifying the aggregated particles is a step of fusing and unifying the aggregated particles while stirring the aggregated particle dispersion in the fusing and unifying tank, wherein the ratio (H / D) of the difference H between the liquid level at the wall of the fusing and unifying tank and the liquid level at the stirring axis with respect to the radius D of the fusing and unifying tank is 0.05 or more and 1 or less, the fusing and unifying tank has an air inlet pipe and an air outlet pipe, and 5 L / (min·m) of the aggregated particle dispersion in the fusing and unifying tank is supplied from the air inlet pipe per unit volume. ３ ) or more 150L / (min・m ３ The aggregated particles are fused and combined while a gas at the following airflow rate is blown into the fusion / combination tank.

2. A method for manufacturing electrostatic image developing toner according to claim 1, wherein the step of fusing and uniting the aggregated particles satisfies at least one of the following conditions (11) to (13). Condition (11): The upper part of the fusion / combination tank has a plurality of openings leading to the outside of the fusion / combination tank system, and the total area ratio of the openings is 5 cm per unit volume of the aggregated particle dispersion. ２ / m ３ More than 8000cm ２ / m ３ The following applies: Condition (12): The temperature inside the fusion / combination tank is (atmospheric pressure - 50) kPa or higher (atmospheric pressure - 0.5 The aggregated particles are fused and combined under reduced pressure to a range of kPa or less. Condition (13): The step of fusing and uniting the aggregated particles is a step of fusing and uniting the aggregated particles while stirring the aggregated particle dispersion liquid in the fusion and unification tank. In the aggregated particle dispersion liquid during the stirring, the ratio (H / D) of the difference H between the liquid level height at the wall surface of the fusion and unification tank and the liquid level height at the stirring shaft to the radius D of the fusion and unification tank is 0.05 or more and 1 or less. The fusion and unification tank has an air introduction pipe and an air discharge pipe. In a state where a gas with an air volume of 5 L / (min·m ３ 2) or more and 150 L / (min·m ３ 2) or less per unit amount of the aggregated particle dispersion liquid in the fusion and unification tank is blown into the fusion and unification tank, the aggregated particles are fused and united.

3. A method for manufacturing electrostatic image developing toner according to claim 1 or claim 2, wherein, in the conditions (1) and (11) above, the number of openings in the upper part of the fusion / unification tank is 2 or more and 30 or less.

4. The method for manufacturing electrostatic image developing toner according to claim 3, wherein the number of openings in the upper part of the fusion / unification tank is 3 or more and 20 or less.

5. A method for producing electrostatic image developing toner according to any one of claims 1 to 4, wherein in the step of fusing and uniting the aggregated particles, a mixed aqueous solution of an acid and a surfactant is added to the aggregated particle dispersion that has reached a temperature of (the glass transition temperature Tg of the resin particles) or (the glass transition temperature Tg + 50°C) or less.

6. The method for producing toner for charge image developing according to claim 5, wherein the temperature of the aggregated particle dispersion when the mixed aqueous solution of the acid and surfactant is added is at a temperature of (the glass transition temperature Tg + 5°C) or higher and (the glass transition temperature Tg + 40°C) or lower.

7. A method for manufacturing electrostatic image developing toner according to any one of claims 1 to 6, wherein in the step of fusing and uniting the aggregated particles, the rate of heating of the aggregated particle dispersion from the start of heating to the fusing and uniting temperature is 0.05°C / min or more and 1°C / min or less.

8. The method for manufacturing electrostatic image developing toner according to claim 7, wherein the heating rate is 0.1°C / min or more and 0.5°C / min or less.

9. The process includes a step of using an organic solvent and an aqueous medium to emulsify a resin, then vacuum distilling the resulting emulsion to remove the organic solvent from the emulsion to form a dispersion containing the resin particles. A method for producing electrostatic image developing toner according to any one of claims 1 to 8, wherein in the step of forming a dispersion containing the resin particles, the volatile base is used as a neutralizing agent to neutralize the resin.

10. The method for producing a toner for electrostatic image developing according to claim 9, wherein the volatile base is ammonia.

11. A method for producing electrostatic image developing toner according to any one of claims 1 to 10, wherein the resin particles are particles containing a resin having an acid value of 5 mg KOH / g or more and 40 mg KOH / g or less.

12. The method for manufacturing a toner for electrostatic image developing according to claim 11, wherein the resin is a polyester resin.

13. A method for manufacturing electrostatic image developing toner according to any one of claims 1 to 12, wherein, in the step of fusing and unifying the aggregated particles, the amount of volatile base in the aggregated particle dispersion when the fusing and unification temperature of the aggregated particle dispersion is reached is 10% by mass or more and 98% by mass or less, relative to the amount of volatile base in the aggregated particle dispersion when heating of the aggregated particle dispersion begins.

14. A method for producing electrostatic image developing toner according to claim 13, wherein, in the step of fusing and uniting the aggregated particles, the amount of the volatile base in the aggregated particle dispersion at the start of heating of the aggregated particle dispersion is 0.005% by mass or more and 1.0% by mass or less relative to the solid content of the aggregated particle dispersion.

15. A method for manufacturing toner for electrostatic image developing according to claim 13 or claim 14, wherein, in the step of fusing and unifying the aggregated particles, the pH of the aggregated particle dispersion at the start of heating the aggregated particle dispersion is 6.5 or more and 9.5 or less, and the pH of the aggregated particle dispersion at the time the fusing and unification temperature is reached is 6 or more and 9 or less.

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