JP6021332B2 - Toner production method - Google Patents

Description

  The present invention relates to a toner production method using an aqueous medium of resin fine particles.

  Aqueous dispersions of resin fine particles are used in various fields such as toner, ink for inkjet printers, liquid developers for electrostatic printing, and the like. In any field, control of the particle size and particle size distribution of the resin fine particles in the aqueous dispersion of resin fine particles is important. Particularly, resin fine particles having a small particle size and a sharp particle size distribution are desired.

  When an aqueous dispersion of resin fine particles is used in the production of toner, an aqueous dispersion of resin fine particles having a more precisely controlled particle size is desired. This is because the particle size and particle size distribution of the resin fine particles greatly affect the toner particle size distribution, shape, and the like, and greatly affect the developability of the toner.

  Patent Document 1 describes a method using an organic solvent called a phase inversion emulsification method as a method for producing resin fine particles. Patent Documents 2 and 3 describe a solvent-free emulsification method in which a resin dispersion is obtained without using an organic solvent from the viewpoint of reducing environmental burden and saving resources.

JP-A-8-21655 JP2004-189765 JP 2007-106906 A

  In the methods described in Patent Documents 1 to 3, when emulsifying a resin having an acid group, adsorption of the surfactant to the resin is inhibited by electrostatic repulsion between the negative charge derived from the acid group and the negative charge of the surfactant. As a result, the adhesion amount of the surfactant becomes uneven. For this reason, the amount of the surfactant adhering to the surface of the dispersion becomes non-uniform, so that the particle size distribution of the resin fine particles to be formed becomes wide and a toner having a desired particle size may not be obtained.

  In recent years, in order to achieve both low-temperature fixability and storage stability in the electrophotographic field, core-shell toners having a structure in which a core made of a low softening point resin is covered with a shell made of a high softening point resin have been widely used. When an aqueous dispersion of resin fine particles having a large particle size and a wide particle size distribution is used as a constituent material of the shell, shell particle adhesion to the core particles becomes non-uniform, and the storage stability of the toner decreases. In order to solve the above problem, it is conceivable to increase the coating amount of the shell, but in this case, the softening point of the entire toner is increased, and the low-temperature fixability is deteriorated. Therefore, in order to achieve both storage stability and low-temperature fixability, it is a big problem to make the resin fine particles sufficiently small and narrow the particle size distribution.

  The present invention solves the above problems. That is, an object of the present invention is to provide a method for producing an aqueous dispersion of resin fine particles having a small particle size and a narrow particle size distribution. Another object of the present invention is to provide a toner production method that achieves both low-temperature fixability and storage stability by using an aqueous dispersion of the resin fine particles.

The present invention
Producing an aqueous dispersion of resin fine particles;
An aqueous dispersion of the resin fine particles and a colorant are mixed, and the resin fine particles and the colorant are aggregated in an aqueous medium to obtain an aggregate having a weight average particle diameter (D4) of 4.5 μm or more and 7.0 μm or less. An aggregation process to form;
A fusing step of heating and fusing the aggregates;
In a method for producing a toner having
The step of producing an aqueous dispersion of the resin fine particles includes:
(I) a mixing step of obtaining a mixture by mixing a resin having an acid group, an anionic surfactant, water and a water-soluble inorganic salt;
(Ii) Stirring of the mixture at a temperature equal to or higher than the glass transition temperature of the resin having an acid group, and an aqueous dispersion of the resin fine particles having a 50% particle size based on volume distribution of 0.02 μm to 1.00 μm Having an emulsification step
The water-soluble inorganic salt is sodium chloride, potassium chloride or lithium chloride;
In the emulsification step, a toner production method, wherein the concentration of the water-soluble inorganic salt in the aqueous phase of the aqueous dispersion is not more than the following critical aggregation concentration.
[Critical aggregation concentration is the volume distribution of the resin fine particles in the aqueous dispersion of the resin fine particles before the addition of the water soluble inorganic salt, in which the volume distribution standard 50% particle size of the resin fine particles added with the water-soluble inorganic salt is 50%. This is the concentration of the water-soluble inorganic salt in the aqueous phase of the aqueous dispersion when it exceeds 1.5 times the distribution standard 50% particle size. ]
Furthermore,
Producing an aqueous dispersion of resin fine particles;
An aqueous dispersion of the resin fine particles and a colorant are mixed, and the resin fine particles and the colorant are aggregated in an aqueous medium to obtain an aggregate having a weight average particle diameter (D4) of 4.5 μm or more and 7.0 μm or less. An aggregation process to form;
A fusing step of heating and fusing the aggregates;
In a method for producing a toner having
The step of producing an aqueous dispersion of the resin fine particles includes:
(I) a mixing step of mixing a resin having an acid group, a solvent in which the resin having the acid group is soluble, and an anionic surfactant to obtain a mixture;
(Ii) An emulsification step of adding a water-soluble inorganic salt and water to the mixture and stirring to obtain an aqueous dispersion of the resin fine particles having a 50% particle size based on volume distribution of 0.02 μm or more and 1.00 μm or less. And the step of producing an aqueous dispersion of the resin fine particles,
In the emulsification step, a method for producing a toner, wherein the concentration of the water-soluble inorganic salt in the aqueous phase of the aqueous dispersion is not more than the critical aggregation concentration defined below.
[Critical aggregation concentration is the volume distribution of the resin fine particles in the aqueous dispersion of the resin fine particles before the addition of the water soluble inorganic salt, in which the volume distribution standard 50% particle size of the resin fine particles added with the water-soluble inorganic salt is 50%. This is the concentration of the water-soluble inorganic salt in the aqueous phase of the aqueous dispersion when it exceeds 1.5 times the distribution standard 50% particle size. ]
About.

  According to the present invention, even when an acid group-containing resin is used, it is possible to provide an aqueous dispersion of resin fine particles having a smaller particle size and a narrower particle size distribution than before. Further, by producing a toner using an aqueous dispersion of resin fine particles having a small particle size and a narrow particle size distribution produced according to the present invention, a toner having both low temperature fixability and storage stability can be obtained.

<Method for producing aqueous dispersion of resin fine particles>
First, the first aspect of the method for producing an aqueous dispersion of resin fine particles will be described.

  The 1st aspect of the manufacturing method of this invention has the mixing process of mixing resin which has an acid group, and anionic surfactant, and obtaining a mixture.

  The resin having an acid group used in the present invention means a resin having a carboxyl group, a sulfo group, or a salt thereof at the end or side chain of a molecular chain. Specifically, an acrylic resin, a methacrylic resin, a styrene-acrylic copolymer, a styrene-methacrylic copolymer, a polyester resin, a polyamic acid resin, and the like can be preferably exemplified. Among these, when used as a toner material, a polyester resin is preferable from the viewpoint that the difference between the softening temperature (Tm) of the toner and the glass transition point (Tg) can be reduced.

  The polyester resin is obtained by polycondensing an acid component and an alcohol component. When the polyester resin is produced, the acid component includes oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, peric acid, glutaconic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, In addition to dicarboxylic acids such as undecane dicarboxylic acid, dodecane dicarboxylic acid, maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, isophthalic acid, terephthalic acid, n-dodecyl succinic acid, n-dedecenyl succinic acid, cyclohexane dicarboxylic acid, Trimellitic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, pyromellitic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1, 3-dicarboxyl-2-methyl-2-methylenecarbox Propane, tri- or higher carboxylic acid, and derivatives such as their anhydrides or lower alkyl esters.

  Examples of the alcohol component include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, , 9-nonanediol, 1,10-decanediol, 1,11-dodecanediol, 1,12-undecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, In addition to aliphatic diols such as 20-eicosanediol, dihydric alcohols such as polyoxyethylenated bisphenol A, polyoxypropylenated bisphenol A, 1,4-cyclohexanedimethanol, 1,3,5-trihydroxy Aromatic alcohols such as methylbenzene, pentaerythritol Dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerin, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane Trivalent alcohol such as trimethylolpropane may be used.

  When used as a toner, the glass transition point (Tg) of the resin having an acid group used in the present invention is preferably 50 ° C. or higher from the viewpoint of blocking prevention, and 80 ° C. or lower from the viewpoint of low-temperature fixability. It is preferable that

  The softening temperature (Tm) of the resin having an acid group used in the present invention is preferably 150 ° C. or less from the viewpoint of low-temperature fixability when used as a toner, and from the viewpoint of heat-resistant storage properties of the toner. 90 degreeC or more is preferable.

  The resin having an acid group used in the present invention has a molecular weight range of 3,500 to 15,000 in the molecular weight distribution measured by gel permeation chromatography (GPC) soluble in tetrahydrofuran (THF) of the resin. It is preferable to have a peak top of the main peak. When the peak top of the main peak is within the above range, the thermal stability is high when an aqueous dispersion of resin fine particles is used in the production of the aggregated toner.

The resin having an acid group used in the present invention preferably has an acid value of 1 mgKOH / g or more and 30 mgKOH / g or less . When the acid value of the resin is 1 or more, the chargeability is high when the toner is used, and scattering and fogging are suppressed. Further, if the acid value is 30 or less, the moisture absorption of the resin is suppressed, and the toner characteristics hardly change even in environments with different temperatures.

  The anionic surfactant used in the present invention includes, as a hydrophobic substituent, a hydrocarbon group having a linear or branched structure, a fluorocarbon chain, or a hydrophobic group having an aromatic ring such as benzene or naphthalene, and a sulfonate ester. , A compound having a hydrophilic group having a carboxylic acid or a sulfonic acid. Examples of the anionic surfactant include sulfate ester salt, sulfonate salt, phosphate ester, soap, amine salt type, and quaternary ammonium salt type. Specifically, fatty acid soaps such as potassium laurate, sodium oleate, and castor oil sodium; sulfates such as octyl sulfate, lauryl sulfate, lauryl ether sulfate, and nonylphenyl ether sulfate; lauryl sulfonate, dodecylbenzene sulfonate, tri Alkylnaphthalene sodium sulfonates such as isopropyl naphthalene sulfonate and dibutyl naphthalene sulfonate; sulfonates such as naphthalene sulfonate formalin condensate, monooctyl sulfosuccinate, dioctyl sulfosuccinate, lauric acid amide sulfonate, oleic acid amide sulfonate; lauryl phosphate; Phosphoric acid esters such as isopropyl phosphate and nonylphenyl ether phosphate Le ethers; dialkyl sulfosuccinate salts such as sodium dioctyl sulfosuccinate; sulfosuccinate salts such as sulfosuccinate lauryl disodium and the like. The surfactant is preferably added so that the concentration in the liquid is equal to or higher than the critical micelle concentration. Surfactant may be used individually by 1 type and may use 2 or more types together.

  In the mixing step in the present invention, the acid group-containing resin and the anionic surfactant may be mixed as they are, or these materials may be mixed in the presence of water.

  The first aspect of the production method of the present invention includes an emulsification step of stirring the mixture in the presence of water and a water-soluble inorganic salt at a temperature equal to or higher than the glass transition point of the resin having an acid group to obtain a resin emulsion. Have.

  Examples of the stirring device include a high-speed rotation type homogenizer and a high-pressure type homogenizer.

  In the emulsification step, a basic substance may be added as necessary. If the resin having an acid group is atomized as it is in an aqueous medium, the pH becomes 3 to 4 and is too biased toward the acidic side. For example, when the resin having an acid group is a hydrolyzable resin such as a polyester resin , Hydrolysis is accelerated. Therefore, it is preferable to add a basic substance, particularly when using a hydrolyzable resin. Basic substances include inorganic bases such as ammonia, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, and potassium bicarbonate; organic bases such as dimethylamine, diethylamine, and triethylamine. Can be mentioned. Among these, from the viewpoint of inhibiting hydrolysis under basic conditions, it is preferable to use weak bases such as dimethylamine and triethylamine.

  When using a basic substance, it is preferable to adjust the addition amount so that the pH in the aqueous medium is 6 to 11. The basic substance tends to reduce the particle size of the resin fine particles as the amount of the basic substance increases. This is because the acid group of the resin takes a salt structure by the basic substance, and the self-emulsifying property of the resin becomes high. However, if the pH in the aqueous medium becomes basic, hydrolysis of the resin may occur. Therefore, when a strong base is used as the basic substance, it is necessary to limit the addition amount so as not to cause hydrolysis. From the above viewpoint, the preferable addition amount of the basic substance is preferably 0.1 equivalents or more and 10.0 equivalents or less, and 0.9 equivalents or more and 3.0 equivalents or less with respect to the number of acid groups of the resin. It is more preferable that

  In the emulsification step in the present invention, the mixture is stirred in the presence of water and a water-soluble inorganic salt. When a water-soluble inorganic salt is present in the emulsification step, cations ionized from the water-soluble inorganic salt shield a negative charge derived from the acid group of the resin. Thereby, the electrostatic repulsion between the negative charge derived from the acid group of the resin and the anionic surface activity is weakened, and the surfactant is considered to adhere to the resin surface in a larger amount and more uniformly. Therefore, an aqueous dispersion of resin fine particles having a small particle size and a sharp particle size distribution can be obtained.

  Examples of the water-soluble inorganic salt include monovalent inorganic salts such as sodium chloride, potassium chloride, and lithium chloride; divalent inorganic salts such as magnesium chloride; and trivalent inorganic salts such as aluminum chloride. In general, a salt having a higher valence has a higher shielding effect, but the resin fine particles tend to aggregate. Therefore, a monovalent inorganic salt is preferably used from the viewpoint that aggregation of resin fine particles hardly occurs.

  On the other hand, when the water-soluble inorganic salt is added when the resin fine particles are dispersed in the aqueous medium, the electric double layer of the resin fine particles is thinned. That is, the electrostatic repulsion between the resin fine particle surfaces is weakened by the cation of the water-soluble inorganic salt, and the resin fine particles become unstable in the aqueous medium. Therefore, when an excessive amount of the water-soluble inorganic salt is added, the resin fine particles are aggregated and the resin fine particles are coarsened. Therefore, in the emulsification step of the present invention, the concentration of the water-soluble inorganic salt in the aqueous phase is adjusted to a critical aggregation concentration or less.

  Specifically, the critical aggregation concentration is measured by the following method. First, an aqueous dispersion of resin fine particles prepared without adding a water-soluble inorganic salt is prepared, and the volume distribution reference 50% particle diameter of the resin fine particles in the aqueous dispersion of the resin fine particles is measured. Next, at 20 ° C., the resin emulsion was stirred at Claremix 2.2S (manufactured by M Technique Co., Ltd.) at a rotation speed of 10,000 r / min, while high concentration (5.0 mol / L for sodium chloride). The aqueous solution of the water-soluble inorganic salt is gradually added, and the volume distribution standard 50% particle size of the resin fine particles is measured at any time. The volume distribution standard 50% particle size of the resin fine particles in the resin emulsion to which the water-soluble inorganic salt is added is 1 of the volume distribution standard 50% particle size of the resin fine particles in the resin emulsion before the addition of the water-soluble inorganic salt. The concentration of the water-soluble inorganic salt in the aqueous phase at the time of exceeding 5 times is defined as the critical aggregation concentration. For measuring the particle size of the resin fine particles, a dynamic light scattering particle size distribution measuring device (Nanotrack UPA150: manufactured by Nikkiso Co., Ltd.) is used, and the particle size is measured according to the operation manual of the device.

  When a water-soluble inorganic salt exceeding the critical aggregation concentration is added, the charge shielding effect becomes too strong, and the resin particles become unstable in the aqueous medium, and thus aggregation occurs during emulsification. As a result, an aqueous dispersion of resin fine particles having a large particle size and a broad particle size distribution is obtained. Therefore, when a monovalent water-soluble inorganic salt is used, the addition amount of the water-soluble inorganic salt is preferably 0.01 mol / L or more and 0.50 mol / L or less, preferably 0.10 mol / L or more and 0.20 mol / L. The following is more preferable.

The emulsification temperature is preferably a high temperature from the viewpoint of lowering the viscosity of the molten resin, but is sufficient if the melt viscosity of the resin having an acid group is 10 ³ Pa · s or less. Moreover, since the hydrolysis of resin may occur when the emulsification temperature is too high, the emulsification temperature is preferably 150 ° C. or lower. In this case, the melt viscosity means the melt viscosity of a resin having an acid group in water.

  An example of detailed procedures of the mixing step and the emulsification step in the first aspect will be described. A resin having an acid group, a surfactant, and a water-soluble inorganic salt are put into an aqueous medium in which a basic substance is present, and then mixed. Next, it heats to temperature higher than the glass transition point (Tg) of resin which has this acid group, stirs a mixture, applying a shear force, and obtains an emulsion. Further, the obtained emulsion is cooled with stirring while applying a shearing force to a temperature not higher than the glass transition point of the resin to obtain an aqueous dispersion of resin fine particles.

  When the heating temperature is 100 ° C. or higher in the emulsification step, the emulsification step may be performed in a container that can be hermetically pressurized.

  In the method for producing an aqueous dispersion of resin fine particles of the present invention, after the emulsification step, the obtained emulsion is cooled to a temperature not higher than Tg of the resin having an acid group while applying a shearing force. Is preferred. The cooling rate in the cooling step is preferably from 0.5 ° C./min to 10.0 ° C./min, more preferably from 1.0 ° C./min to 10.0 ° C./min, It is particularly preferable that the temperature is from 0 ° C / min to 5.0 ° C / min. When the cooling rate is within the above range, generation of coarse particles and broadening of the particle size distribution of resin fine particles can be suppressed. In addition, when cooling the aqueous dispersion of resin fine particles from a temperature of Tg or less to room temperature, the cooling rate is not particularly limited.

  The resin fine particles contained in the aqueous dispersion of resin fine particles preferably have a volume distribution standard 50% particle size of 0.02 μm or more and 1.00 μm or less, and more preferably 0.02 μm or more and 0.40 μm or less. If the volume distribution reference 50% particle diameter of the resin fine particles is within the above range, the stability of the resin fine particles is good, and sedimentation separation hardly occurs. Further, when used for toner production by the aggregation method, it becomes easy to keep the composition of each toner particle uniform.

  In order to adjust the 50% particle size of the resin fine particle based on the volume distribution to the above range, the amount of the surfactant, the amount of the water-soluble inorganic salt, the amount of the basic substance, the heating temperature during the emulsification step, and the emulsification The strength of the shearing force in the process and the cooling process may be adjusted as appropriate.

  Next, a second aspect of the method for producing an aqueous dispersion of resin fine particles will be described.

  In the second embodiment, after the mixing step of mixing a resin having an acid group and a solvent in which the resin having an acid group is soluble to obtain a mixture, a shearing force is applied to stir the mixture to obtain a resin emulsion. An emulsification step is performed. At that time, the emulsification step is performed in the presence of an anionic surfactant, a water-soluble inorganic salt having a critical aggregation concentration or less, and water.

  Regarding the resin having an acid group, the anionic surfactant, the basic substance, and the water-soluble inorganic salt in the second aspect, the same ones as described in the first aspect can be used.

  The resin-soluble solvent used in the second embodiment is a solvent capable of dissolving 10 parts by mass of an acid group-containing resin with respect to 100 parts by mass of the solvent in a range from room temperature to an emulsification temperature. means. The solvent may be water-soluble or water-insoluble, but a water-soluble solvent having a relatively low boiling point is preferable from the viewpoint of removing the solvent. Specific examples include ethyl acetate, butyl acetate, methyl ethyl ketone, tetrahydrofuran, dioxane, methanol, ethanol and isopropyl alcohol. These solvents can be used alone or in admixture of two or more.

  In the emulsification step in the second aspect, the same emulsification apparatus, basic substance, and water-soluble inorganic salt as in the first aspect can be used.

  An example of detailed procedures of the mixing step and the emulsification step in the second aspect will be described. A resin having an acid group, an anionic surfactant, a basic substance, and a solvent in which the resin is soluble are placed in the container, and stirring is performed until the resin is uniformly dissolved in the solvent. Next, while applying a shearing force, a mixture of a water-soluble inorganic salt and water is dropped, and the resin is phase-inverted and emulsified. The temperature at which phase inversion emulsification is carried out is preferably below the boiling point of the solvent from the viewpoint of handling, and more preferably at room temperature. Thereafter, the solvent is removed by heating or / and decompressing to obtain an aqueous dispersion of resin fine particles.

  In the second embodiment, the anionic surfactant is not necessarily added from the mixing step, and may be added together with water or a water-soluble inorganic salt, for example, in the emulsification step.

<Toner production method>
The aqueous dispersion of resin fine particles obtained in the present invention can be used for toner production such as an agglomeration method. When the toner is produced by a coagulation method, by mixing the colorant with an aqueous dispersion of the resin fine particles, aggregating step of forming an aggregate of the resin fine particles and colorant are aggregated in an aqueous medium, heating the aggregates and, through the fusion process Ru fused to obtain toner. Hereinafter, the toner production method will be described in detail, but the toner production method in the present invention is not limited to the following method.

  In the agglomeration step, the above-mentioned aqueous dispersion of resin fine particles, an aqueous dispersion of colorant fine particles, and, if necessary, a toner component such as a release agent are mixed to prepare a liquid mixture. The particles contained in the particles are aggregated to form aggregates. Examples of the method for forming the aggregate include a method in which a flocculant is added and mixed in the above-mentioned mixed solution, the temperature is adjusted, and mechanical power is appropriately applied.

  The colorant may be a pigment or a dye, but a pigment is preferably used from the viewpoint of light resistance and the like. In this case, the pigment is an organic or inorganic colored compound that is insoluble in water.

  The following are mentioned as an inorganic pigment. Oxide pigments such as cobalt blue, celsian blue, cobalt violet, cobalt green, zinc white, titanium white, light red, chrome oxide green, and mars black; hydroxide pigments such as viridan, yellow ocher, and alumina white; ultramarine Silicate pigments such as talc and white carbon; metal powders such as gold powder, silver powder and bronze powder; carbon black. The following are mentioned as an organic pigment. β-naphthol azo compounds, naphthol AS azo compounds, monoazo or disazo acetoacetate allylide azo compounds, pyrazone azo compounds, condensed azo pigments, phthalocyanine compounds, subphthalocyanine compounds, porphyrin compounds, quinacridone compounds , Isoindoline compounds, isoindolinone compounds, selenium compounds, perylene compounds, perinone compounds, thioindigo compounds, dioxazine compounds, quinophthalone compounds, diketopyrrolopyrrole compounds. The following are examples of commercially available color materials for black, cyan, magenta, and yellow.

  Raven1060, Raven1080, Raven1170, Raven1200, Raven1250, Raven1255, Raven1500, Raven2000, Raven3500, Raven5000, Raven5000, Raven5000, Raven5000, Raven5000, Raven5000, Raven5000, Raven5000, Raven5000, Raven5000, Raven5000, Raven5000, Raven5000 , MOGUL-L, Regal 400R, Regal 660R, Regal 330R, Monarch 800, Monarch 880, Monarch 900, Monarch 1000, Monarch 1300, Monarch 1400 (above, manufactured by Cabot Corporation); Color Black F 1, Color Black FW2, Color Black FW200, Color Black 18, Color Black S160, Color Black S170, Special Black 4P, Special Black 4A, Special Black 140P, BlackPr 140, Color Black S170, Color Black S170, Color Black S170, Special Black No. 25, no. 33, no. 40, no. 47, no. 52, no. 900, no. 2300, MCF-88, MA600, MA7, MA8, MA100 (manufactured by Mitsubishi Chemical Corporation).

  Examples of cyan color materials include C.I. I. Pigment Blue-1, C.I. I. Pigment Blue-2, C.I. I. Pigment Blue-3, C.I. I. Pigment Blue-15, C.I. I. Pigment Blue-15: 2, C.I. I. Pigment Blue-15: 3, C.I. I. Pigment Blue-15: 4, C.I. I. Pigment Blue-16, C.I. I. Pigment Blue-22, C.I. I. Pigment Blue-60 and the like.

  Examples of the magenta color material include C.I. I. Pigment Red-5, C.I. I. Pigment Red-7, C.I. I. Pigment Red-12, C.I. I. Pigment Red-48, C.I. I. Pigment Red-48: 1, C.I. I. Pigment Red-57, C.I. I. Pigment Red-112, C.I. I. Pigment Red-122, C.I. I. Pigment Red-123, C.I. I. Pigment Red-146, C.I. I. Pigment Red-168, C.I. I. Pigment Red-184, C.I. I. Pigment Red-202, C.I. I. Pigment Red-207 and the like.

  Examples of yellow color materials include C.I. I. Pigment Yellow-12, C.I. I. Pigment Yellow-13, C.I. I. Pigment Yellow-14, C.I. I. Pigment Yellow-16, C.I. I. Pigment Yellow-17, C.I. I. Pigment Yellow-74, C.I. I. Pigment Yellow-83, C.I. I. Pigment Yellow-93, C.I. I. Pigment Yellow-95, C.I. I. Pigment Yellow-97, C.I. I. Pigment Yellow-98, C.I. I. Pigment Yellow-114, C.I. I. Pigment Yellow-128, C.I. I. Pigment Yellow-129, C.I. I. Pigment Yellow-151, C.I. I. Pigment Yellow-154 and the like.

  Examples of the release agent include the following. Low molecular weight polyolefins such as polyethylene; silicones having a melting point (softening point); fatty acid amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide, stearic acid amide; ester waxes such as stearyl stearate; carnauba wax Plant waxes such as rice wax, candelilla wax, tree wax and jojoba oil; animal waxes such as beeswax; minerals such as montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, Fischer-Tropsch wax and ester wax Petroleum wax; and modified products thereof.

  A charge control agent may be added to the toner as necessary. As the charge control agent, a chrome azo dye, an iron azo dye, an aluminum azo dye, a salicylic acid metal complex, a polymer charge control agent, or the like can be used.

  Examples of the flocculant include metal salts of monovalent metals such as sodium and potassium; metal salts of divalent metals such as calcium and magnesium; metal salts of trivalent metals such as iron and aluminum. When adding and mixing the flocculant, the temperature is preferably equal to or lower than the glass transition point (Tg) of the resin particles (resin having an acid group) contained in the mixed solution. When the above mixing is performed under this temperature condition, aggregation proceeds in a stable state. The said mixing can be performed using a well-known mixing apparatus, a homogenizer, a mixer, etc.

  The average particle size of the aggregate formed here is not particularly limited, but it is usually preferable to control the average particle size to be approximately the same as the average particle size of the toner particles to be obtained. The average particle size of the aggregate can be easily controlled by, for example, appropriately setting / changing the temperature at the time of addition / mixing of the flocculant or the like and the conditions of the stirring / mixing.

The fusing step, the aggregate, by heating the glass transition point (Tg) or more of the first resin, obtained in Rukoto fused, toner particles aggregate surface was smoothed (core particles) process is there. By this step, the surface area of the agglomerates is reduced, and toner particles having a good shape can be obtained. In addition, when shell particles are attached in the attaching step described later, the shell particles are efficiently attached to the core particles. Before entering the primary fusing step, a chelating agent, a pH adjusting agent, a surfactant and the like can be appropriately added in order to prevent fusion between toner particles.

  Examples of chelating agents include alkali metal salts such as ethylenediaminetetraacetic acid and its Na salt, sodium gluconate, sodium tartrate, potassium citrate, sodium citrate, nitrotriacetate salts, many containing both functionality of COOH and OH. And water-soluble polymers (polyelectrolytes).

  The heating temperature in the fusion step may be between the glass transition point (Tg) of the resin having an acid group contained in the aggregate and the temperature at which the resin is thermally decomposed. As the heating / fusion time, a short time is sufficient if the heating temperature is high, and a long time is required if the heating temperature is low. That is, the heating / fusion time depends on the temperature of heating and cannot be defined unconditionally, but is generally 10 minutes to 10 hours. Note that the toner cooling step described below may be performed as necessary after the fusing step.

  The toner cooling step is a step of cooling the temperature of the aqueous medium containing the toner particles to a temperature lower than the glass transition point (Tg) of the resin having an acid group. If the aqueous medium is not cooled to a temperature lower than Tg, coarse particles are generated when the flocculant is added when the adhesion step described later is performed. A specific cooling rate is 0.1 to 50 ° C./min. In addition, as a core particle, what was obtained through the aggregation process and fusion process mentioned above is preferable, However, You may use the core particle obtained by the other manufacturing method.

  Next, the attaching process for attaching the shell particles to the core particles will be described in detail. The adhesion step refers to an aqueous dispersion of the second resin fine particles having the second resin and the core at a temperature lower than the glass transition point (Tg) of the resin having the acid group (first resin) contained in the core particles. In this step, the particles and the aggregating agent are mixed to attach the second resin fine particles in the aqueous dispersion to the surface of the core particles. The adhering step is preferably performed after the toner cooling step.

  Examples of the flocculant include metal salts of monovalent metals such as sodium and potassium; metal salts of divalent metals such as calcium and magnesium; metal salts of trivalent metals such as iron and aluminum. The flocculant may be mixed simultaneously with the aqueous dispersion of the second resin fine particles, or may be mixed before and after that. In addition, you may perform the following secondary fusion process, washing | cleaning, and a secondary cooling process as needed after an adhesion process.

The secondary fusing step, the resulting shell adhering member by adhesion process, by heating the glass transition point (Tg) or more of the resin (first resin) having an acid group, in Rukoto fusing, the particle surface This is a smoothing process. The core resin and the shell resin are sufficiently fixed by the secondary fusion process, and the shell is prevented from being detached from the core particles by operations such as washing and filtration described later. Before entering the secondary fusion step, a chelating agent, a pH adjuster, a surfactant, and the like can be appropriately added in order to prevent fusion between toner particles.

  The heating temperature in the secondary fusion step may be between the glass transition point (Tg) of the resin having an acid group contained in the aggregate and the temperature at which the resin is thermally decomposed. As the heating / fusion time, a short time is sufficient if the heating temperature is high, and a long time is required if the heating temperature is low. That is, the heating / fusion time depends on the temperature of heating and cannot be defined unconditionally, but is generally 10 minutes to 10 hours.

  After the secondary coalescence step, the obtained particles are cooled to room temperature under appropriate conditions, and washed, filtered, dried, etc. to obtain toner particles. Further, inorganic particles such as silica, alumina, titania and calcium carbonate, and resin particles such as vinyl resin, polyester resin and silicone resin may be added to the surface of the obtained toner particles. These inorganic particles and resin particles function as external additives such as fluidity aids and cleaning aids.

  The weight average particle diameter (D4) of the toner is preferably 4.5 to 7.0 μm, and more preferably 5.0 to 6.5 μm.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, the aspect of this invention is not limited to these.

<Measurement of Molecular Weight Distribution, Weight Average Molecular Weight (Mw), Number Average Molecular Weight (Mn), etc. Measured by Gel Permeation Chromatography (GPC) of Resin Tetrahydrofuran (THF)>
The molecular weight distribution, weight average molecular weight (Mw), number average molecular weight (Mn) and the like measured by GPC of the THF soluble content of the resin fine particles are determined as follows.

The column is stabilized in a heat chamber at 40 ° C., and tetrahydrofuran (THF) as a solvent is allowed to flow through the column at this temperature at a flow rate of 1 ml / min, and about 100 μl of THF sample solution is injected and measured. In measuring the molecular weight of a sample, the molecular weight distribution of the sample is calculated from the relationship between the logarithmic value of a calibration curve prepared from several types of monodisperse polystyrene standard samples and the number of counts. As a standard polystyrene sample for preparing a calibration curve, for example, a standard polystyrene sample having a molecular weight of about 10 ² to 10 ⁷ manufactured by Tosoh Corporation or Showa Denko is preferably used. is there. An RI (refractive index) detector is used as the detector. As the column, it is preferable to combine a plurality of commercially available polystyrene gel columns. Examples include combinations of TSKgel G1000H (HXL), G2000H (HXL), G3000H (HXL), G4000H (HXL), G5000H (HXL), G6000H (HXL), G7000H (HXL), and TSKguardcolumn.

  The sample is prepared as follows.

  Place the resin (sample) in tetrahydrofuran (THF), leave it for several hours, shake well, mix well with THF until the sample is no longer united, and let stand for more than 12 hours. At this time, the standing time in THF is set to be 24 hours or longer. Thereafter, a sample processing filter (pore size 0.45 to 0.5 μm, for example, Mysori Disc H-25-5: manufactured by Tosoh Corporation, Excro Disc 25CR: manufactured by Gelman Science Japan Co., Ltd., etc. can be used) is passed. This is used as a GPC sample. The sample concentration is adjusted so that the resin component is 0.5 to 5 mg / ml.

<Measurement of acid value of resin>
The acid value of the resin is determined as follows. The basic operation conforms to JIS-K0070. The acid value indicates the number of mg of potassium hydroxide required to neutralize the acid group contained in 1 g of the sample.

(1) Reagent (a) Solvent: 0.1 mol / L potassium potassium hydroxide with phenolphthalein as an indicator immediately before use of ethyl ether-ethyl alcohol mixture (1 + 1 or 2 + 1) or benzene-ethyl alcohol mixture (1 + 1 or 2 + 1) Neutralize with alcohol solution.
(B) Phenolphthalein solution: 1 g of phenolphthalein is dissolved in 100 ml of ethyl alcohol (95 v / v%).
(C) 0.1 mol / L potassium hydroxide-ethyl alcohol solution: Dissolve 7.0 g of potassium hydroxide in as little water as possible, add ethyl alcohol (95 v / v%) to 1 liter, and leave it for 2 to 3 days. I have. The standardization is performed according to JIS K 8006 (basic matters concerning titration during the reagent content test).

(2) Operation Weigh 1-20 g of resin (sample) correctly, add 100 ml of solvent and a few drops of phenolphthalein solution as an indicator, and shake well until the sample is completely dissolved. In the case of a solid sample, dissolve it by heating on a water bath. After cooling, this is titrated with a 0.1 mol / L potassium hydroxide ethyl alcohol solution, and the end point of neutralization is taken when the indicator is slightly red for 30 seconds.

(3) Calculation formula The acid value is calculated by the following formula.
A = B × f × 5.661 / S
A: Acid value B: Amount of 0.1 mol / L potassium hydroxide ethyl alcohol solution used (ml)
f: Factor of 0.1 mol / L potassium hydroxide ethyl alcohol solution S: Sample (g)

<Particle size distribution analysis of resin fine particles and colorant fine particles>
For the analysis of the particle size distribution, a dynamic light scattering type particle size distribution measuring device (Nanotrack UPA150: manufactured by Nikkiso Co., Ltd.) is used, and the particle size distribution is measured according to the operation manual of the device. After dropping the surfactant aqueous solution into ion-exchanged water, the resin fine particle or colorant fine particle dispersion is adjusted to the optimum concentration of the device, and dispersion treatment is performed for 30 seconds with an ultrasonic disperser. The obtained dispersion treatment liquid is measured, and the volume distribution reference 50% particle size and coefficient of variation are obtained.

<Toner particle size distribution analysis>
The particle size distribution of the toner is measured by particle size distribution analysis by the Coulter method. As a measuring device, Multisizer IV (manufactured by Coulter, Inc.) is used, and measurement is performed according to the operation manual of the device. About 1% sodium chloride aqueous solution is prepared using 1st grade sodium chloride as electrolyte solution. As the electrolytic solution, for example, ISOTON-II (manufactured by Coulter Scientific Japan) can be used. Specifically, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant in 100 to 150 ml of the electrolytic aqueous solution, and 2 to 20 mg of a measurement sample (toner) is further added. Add. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes. The obtained dispersion treatment liquid is subjected to measurement of the volume and number of toners of 2.00 μm or more by means of the measurement apparatus equipped with a 100 μm aperture as an aperture, and the volume distribution and number distribution of the toner are calculated. From the calculation result, the weight average particle diameter (D4) of the toner is obtained.

<Measurement of glass transition point (Tg) of resin>
The glass transition point (Tg) of the resin is measured using a differential scanning calorimeter (DSC) measuring device (DSC822: manufactured by METTLER TOLEDO). In the DSC measurement, measurement is performed with a differential scanning calorimeter of high accuracy internal heat input compensation type from the measurement principle. The measurement method is performed according to ASTM D3418-82. Specifically, Tg is calculated from the DSC curve measured when the temperature is raised and lowered once, the previous history is taken, and the temperature is raised at 10 ° C./min. The central value of the intersection point between the baseline before and after the endotherm and the tangent to the endothermic curve is defined as Tg (° C.).

<Measurement of softening temperature (Tm) of resin>
The softening temperature (Tm) of the resin is measured using a flow tester (CFT-500D: manufactured by Shimadzu Corporation). A sample (resin) 1.5 g to be measured is weighed, a die having a height of 1.0 mm and a diameter of 1.0 mm is used, a heating rate of 4.0 ° C./min, a preheating time of 300 seconds, a load of 5 kg, and a measuring temperature. The measurement is performed in the range of 60.0 to 200.0 ° C. An intermediate value between the melting start temperature and the melting end temperature is defined as a softening temperature (Tm).

<Production of aqueous dispersion of resin fine particles>
[Resin production example 1]
25 parts by mass of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 25 parts by mass of polyoxyethylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, After charging 20 parts by mass of terephthalic acid, 30 parts by mass of fumaric acid and 0.03 parts by mass of dibutyltin oxide into a three-necked flask and stirring at 230 ° C. for 24 hours under a nitrogen stream, 4 parts by mass of trimellitic acid was added. The mixture was added and stirred at 200 ° C. for 30 minutes. Then, while maintaining the temperature, the mixture was stirred for 1 hour under a reduced pressure of 5 mmHg to obtain a polyester resin 1 having an Mw of 10,500, an Mn of 3,200, a Tg of 52 ° C., and an acid value of 15 mgKOH / g.

[Resin production example 2]
Three mouthpieces of 50 parts by mass of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 28 parts by mass of terephthalic acid, 20 parts by mass of isophthalic acid, and 0.03 parts by mass of dibutyltin oxide The flask was charged and stirred at 230 ° C. for 24 hours under a nitrogen stream, and then 2 parts by weight of trimellitic acid was added and stirred at 200 ° C. for 1 hour. Thereafter, the polyester resin 2 having an Mw of 20,500, an Mn of 7,200, a Tg of 71 ° C., and an acid value of 9 mgKOH / g was obtained by stirring for 4 hours under a reduced pressure of 3 mmHg while maintaining the temperature. .

[Resin Production Example 3]
Three mouthpieces of 50 parts by mass of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 28 parts by mass of terephthalic acid, 20 parts by mass of isophthalic acid, and 0.03 parts by mass of dibutyltin oxide The flask was charged and stirred at 230 ° C. for 24 hours under a nitrogen stream, and then 1 part by weight of trimellitic acid was added and stirred at 200 ° C. for 1 hour. Then, the polyester resin 3 having Mw of 21,500, Mn of 7,400, Tg of 73 ° C., and acid value of 2 mgKOH / g was obtained by stirring for 4 hours while reducing the pressure at 1 mmHg.

[Resin Production Example 4]
Three mouthpieces of 50 parts by mass of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 28 parts by mass of terephthalic acid, 20 parts by mass of isophthalic acid, and 0.03 parts by mass of dibutyltin oxide The flask was charged and stirred at 230 ° C. for 24 hours under a nitrogen stream, and then 3 parts by weight of trimellitic acid was added and stirred at 200 ° C. for 30 minutes. Then, the polyester resin 4 with Mw of 22,500, Mn of 7,200, Tg of 72 ° C., and acid value of 20 mgKOH / g was obtained by stirring for 2 hours under a reduced pressure of 5 mmHg while maintaining the temperature.

[Resin production example 5]
Three mouthpieces of 50 parts by mass of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 28 parts by mass of terephthalic acid, 20 parts by mass of isophthalic acid, and 0.03 parts by mass of dibutyltin oxide The flask was charged and stirred at 230 ° C. for 24 hours under a nitrogen stream, 4 parts by weight of trimellitic acid was added, and the mixture was stirred at 200 ° C. for 30 minutes. Thereafter, the mixture was stirred for 1 hour under a reduced pressure of 5 mmHg while maintaining the temperature to obtain a polyester resin 5 having an Mw of 23,500, an Mn of 6,800, a Tg of 71 ° C., and an acid value of 30 mgKOH / g.

[Example 1]
Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK) 5.4 parts by mass, N, N-diethylaminoethanol (basic substance) 8.46 parts by mass, and sodium chloride 0.80 parts by mass (0.10 mol) / L) was dissolved in 142 parts by mass of ion-exchanged water (aqueous medium) to prepare a dispersion medium liquid. This dispersion medium liquid was put into a 350 ml pressure-resistant round bottom stainless steel container, and then 108 parts by mass of polyester resin 1 was added and mixed.

  Next, a high-speed shearing emulsifier CLEARMIX (M Technique Co., Ltd .: CLM-2.2S) was hermetically connected to the pressure-resistant round bottom stainless steel container. The mixture in the sealed container was heated to 140 ° C., the rotor rotation speed of CLEARMIX was set to 20,000 r / min, and stirred for 10 minutes while applying a shearing force. Thereafter, cooling is performed at a cooling rate of 1.0 ° C./min while maintaining a rotation of 20,000 r / min until 50 ° C., and the 50% particle size based on the volume distribution of the resin fine particles is 0.16 μm, An aqueous dispersion 1 of resin fine particles having a variation coefficient of 32% was obtained.

  In addition, when the critical aggregation density | concentration of sodium chloride in the said emulsification conditions was measured separately, the critical aggregation density | concentration was 0.70 mol / L.

[Comparative Example 1]
Emulsification was carried out in the same manner as in Example 1 except that sodium chloride was not added, to obtain an aqueous dispersion 2 of resin fine particles. The resin fine particles obtained had a 50% particle size of 0.33 μm based on volume distribution and a coefficient of variation of 122%.

[Example 2]
Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK) was 21.6 parts by mass, N, N-diethylaminoethanol (basic substance) was 5.07 parts by mass, and the resin was polyester resin 2, An aqueous dispersion 3 of resin fine particles having a 50% particle size of 0.20 μm based on the volume distribution of resin fine particles and a coefficient of variation of 40% was obtained under the same conditions as in Example 1. In addition, when the critical aggregation concentration in the said emulsification conditions was measured separately, the critical aggregation concentration was 0.70 mol / L.

[Comparative Example 2]
Emulsification was performed in the same manner as in Example 2 except that sodium chloride was not added, to obtain an aqueous dispersion 4 of resin fine particles. The resin fine particles obtained had a 50% particle size of 0.35 μm based on volume distribution and a coefficient of variation of 110%.

Example 3
Except that N, N-diethylaminoethanol (basic substance) was 1.13 parts by mass and the resin was polyester resin 3, it was performed under the same conditions as in Example 2, and the 50% particle size on the basis of volume distribution of resin fine particles was An aqueous dispersion 5 of resin fine particles having a variation coefficient of 0.25 μm and 50% was obtained. In addition, when the critical aggregation concentration in the said emulsification conditions was measured separately, the critical aggregation concentration was 0.68 mol / L.

[Comparative Example 3]
Emulsification was carried out in the same manner as in Example 3 except that sodium chloride was not added, to obtain an aqueous dispersion 6 of resin fine particles. The resin fine particles obtained had a 50% particle size of 0.40 μm based on volume distribution and a coefficient of variation of 130%.

Example 4
Except that N, N-diethylaminoethanol (basic substance) was 8.46 parts by mass and the resin was polyester resin 4, it was performed under the same conditions as in Example 2, and the 50% particle size on the basis of volume distribution of resin fine particles was An aqueous dispersion 7 of resin fine particles having 0.18 μm and a variation coefficient of 35% was obtained. In addition, when the critical aggregation concentration in the said emulsification conditions was measured separately, the critical aggregation concentration was 0.73 mol / L.

[Comparative Example 4]
Emulsification was carried out in the same manner as in Example 4 except that sodium chloride was not added to obtain an aqueous dispersion 8 of resin fine particles. The resin fine particles obtained had a 50% particle size of 0.34 μm based on volume distribution and a coefficient of variation of 103%.

Example 5
Except that 11.2 parts by mass of N, N-diethylaminoethanol (basic substance) and polyester resin 5 were used as the resin, it was carried out under the same conditions as in Example 2, and the 50% particle size on the basis of volume distribution of resin fine particles was An aqueous dispersion 9 of resin fine particles having 0.18 μm and a coefficient of variation of 30% was obtained. In addition, when the critical aggregation concentration in the said emulsification conditions was measured separately, the critical aggregation concentration was 0.75 mol / L.

[Comparative Example 5]
Emulsification was carried out in the same manner as in Example 5 except that sodium chloride was not added to obtain an aqueous dispersion 10 of resin fine particles. The resin fine particles obtained had a 50% particle size of 0.29 μm based on volume distribution and a coefficient of variation of 63%.

Example 6
The same conditions as in Example 2 except that 1.13 parts by mass of N, N-diethylaminoethanol (basic substance) and the resin was a styrene-acrylic acid copolymer having an acid value of 2 (Tg = 72 ° C.). Thus, an aqueous dispersion 11 of resin fine particles having a 50% particle size of 0.22 μm based on the volume distribution of the resin fine particles and a coefficient of variation of 69% was obtained. In addition, when the critical aggregation concentration in the said emulsification conditions was measured separately, the critical aggregation concentration was 0.66 mol / L.

[Comparative Example 6]
Emulsification was carried out in the same manner as in Example 6 except that sodium chloride was not added to obtain an aqueous dispersion 12 of resin fine particles. The resin fine particles obtained had a 50% particle size of 0.50 μm and a coefficient of variation of 110% based on volume distribution.

Example 7
Under the same conditions as in Example 2, except that 5.07 parts by mass of N, N-diethylaminoethanol (basic substance) and a styrene-acrylic acid copolymer having an acid value of 9 (Tg = 71 ° C.) were used. As a result, an aqueous dispersion 13 of resin fine particles having a 50% particle size of 0.23 μm based on the volume distribution of the resin fine particles and a variation coefficient of 60% was obtained. In addition, when the critical aggregation concentration in the said emulsification conditions was measured separately, the critical aggregation concentration was 0.68 mol / L.

[Comparative Example 7]
Emulsification was carried out in the same manner as in Example 7 except that sodium chloride was not added to obtain an aqueous dispersion 14 of resin fine particles. The obtained resin fine particles had a 50% particle size of 0.45 μm based on volume distribution and a coefficient of variation of 130%.

Example 8
Under the same conditions as in Example 2, except that 8.46 parts by mass of N, N-diethylaminoethanol (basic substance) and a styrene-acrylic acid copolymer having an acid value of 15 (Tg = 71 ° C.) were used. As a result, an aqueous dispersion 15 of resin fine particles having a 50% particle size of 0.21 μm and a coefficient of variation of 42% based on the volume distribution of the resin fine particles was obtained. In addition, when the critical aggregation concentration in the said emulsification conditions was measured separately, the critical aggregation concentration was 0.73 mol / L.

[Comparative Example 8]
Emulsification was carried out in the same manner as in Example 8 except that sodium chloride was not added, to obtain an aqueous dispersion 16 of resin fine particles. The resin fine particles obtained had a 50% particle size of 0.40 μm based on volume distribution and a coefficient of variation of 75%.

Example 9
Under the same conditions as in Example 2, except that 11.2 parts by mass of N, N-diethylaminoethanol (basic substance) and styrene-acrylic acid copolymer having an acid value of 20 (Tg = 71 ° C.) were used. As a result, an aqueous dispersion 17 of resin fine particles having a 50% particle size of 0.20 μm based on the volume distribution of the resin fine particles and a coefficient of variation of 38% was obtained. In addition, when the critical aggregation concentration in the said emulsification conditions was measured separately, the critical aggregation concentration was 0.75 mol / L.

[Comparative Example 9]
Emulsification was carried out in the same manner as in Example 9 except that sodium chloride was not added, to obtain an aqueous dispersion 18 of resin fine particles. The resin fine particles obtained had a 50% particle size of 0.35 μm based on volume distribution and a coefficient of variation of 60%.

Example 10
Except that the heating temperature was set to 100 ° C., it was performed under the same conditions as in Example 2 and the resin fine particle aqueous dispersion 19 having a 50% particle size of 0.30 μm and a coefficient of variation of 55% based on the volume distribution of the fine resin particles. Got. In addition, when the critical aggregation concentration in the said emulsification conditions was measured separately, the critical aggregation concentration was 0.72 mol / L.

[Comparative Example 10]
Emulsification was carried out in the same manner as in Example 10 except that sodium chloride was not added, to obtain an aqueous dispersion 20 of resin fine particles. The resin fine particles obtained had a 50% particle size of 0.60 μm based on volume distribution and a coefficient of variation of 156%.

Example 11
Except that the heating temperature was 120 ° C., it was carried out under the same conditions as in Example 2, and the resin fine particle aqueous dispersion 21 having a 50% particle diameter of 0.22 μm and a coefficient of variation of 42% based on the volume distribution of the resin fine particles. Got. In addition, when the critical aggregation concentration in the said emulsification conditions was measured separately, the critical aggregation concentration was 0.71 mol / L.

[Comparative Example 11]
Emulsification was carried out in the same manner as in Example 11 except that sodium chloride was not added, to obtain an aqueous dispersion 22 of resin fine particles. The obtained resin fine particles had a 50% particle size of 0.51 μm based on volume distribution and a coefficient of variation of 60%.

Example 12
Except that sodium chloride was changed to 0.04 parts by mass (addition amount corresponding to 0.01 mol / L), the same procedure as in Example 2 was performed, and the 50% particle size based on the volume distribution of the resin fine particles was 0.30 μm. An aqueous dispersion 23 of resin fine particles having a coefficient of variation of 98% was obtained. Resin fine particles having a smaller particle diameter and a narrower particle size distribution than the aqueous dispersion 4 to which no salt was added were obtained.

Example 13
Except that sodium chloride was changed to 1.6 parts by mass (addition amount corresponding to 0.20 mol / L), it was performed under the same conditions as in Example 2, and the 50% particle size on the basis of volume distribution of resin fine particles was 0.21 μm. An aqueous dispersion 24 of resin fine particles having a coefficient of variation of 35% was obtained.

Example 14
Except that sodium chloride was changed to 5.2 parts by mass (addition amount corresponding to 0.65 mol / L), it was performed under the same conditions as in Example 2, and the 50% particle size on the basis of volume distribution of resin fine particles was 0.22 μm. An aqueous dispersion 25 of resin fine particles having a coefficient of variation of 31% was obtained.

[Comparative Example 12]
Emulsification was carried out in the same manner as in Example 2 except that the addition amount of sodium chloride was changed to 6.0 parts by mass (addition amount corresponding to 0.75 mol / L) to obtain an aqueous dispersion 26 of resin fine particles. The resin fine particles obtained had a 50% particle size of 0.42 μm based on volume distribution and a coefficient of variation of 115%.

Example 15
Except that sodium chloride was changed to 0.04 parts by mass (addition amount corresponding to 0.01 mol / L), the same conditions as in Example 3 were used, and the 50% particle size based on the volume distribution of resin fine particles was 0.39 μm. An aqueous dispersion 27 of resin fine particles having a coefficient of variation of 125% was obtained. Resin fine particles having a smaller particle size and a narrower particle size distribution were obtained than the aqueous dispersion 6 to which no salt was added.

Example 16
Except that sodium chloride was changed to 1.6 parts by mass (addition amount corresponding to 0.20 mol / L), it was performed under the same conditions as in Example 3, and the 50% particle size based on the volume distribution of the resin fine particles was 0.25 μm. An aqueous dispersion 28 of resin fine particles having a coefficient of variation of 48% was obtained.

Example 17
Except that sodium chloride was changed to 5.1 parts by mass (addition amount corresponding to 0.63 mol / L), it was performed under the same conditions as in Example 3, and the 50% particle size based on volume distribution of resin fine particles was 0.27 μm. An aqueous dispersion 29 of resin fine particles having a variation coefficient of 47% was obtained.

[Comparative Example 13]
Emulsification was performed in the same manner as in Example 3 except that the addition amount of sodium chloride was 5.9 parts by mass (the addition amount corresponding to 0.73 mol / L, exceeding the critical aggregation concentration in this emulsification condition). An aqueous dispersion 30 was obtained. The resin fine particles obtained had a 50% particle size of 0.46 μm and a coefficient of variation of 144% based on the volume distribution.

Example 18
Except that sodium chloride was changed to 0.04 parts by mass (addition amount corresponding to 0.01 mol / L), the same procedure as in Example 4 was performed, and the 50% particle size based on the volume distribution of the resin fine particles was 0.24 μm. An aqueous dispersion 31 of resin fine particles having a coefficient of variation of 66% was obtained. Resin fine particles having a smaller particle size and a narrower particle size distribution than the aqueous dispersion 8 to which no salt was added were obtained.

Example 19
Except that sodium chloride was changed to 1.6 parts by mass (addition amount corresponding to 0.20 mol / L), it was carried out under the same conditions as in Example 4, and the 50% particle size on the basis of volume distribution of resin fine particles was 0.21 μm. An aqueous dispersion 32 of resin fine particles having a coefficient of variation of 32% was obtained.

Example 20
Except that sodium chloride was changed to 5.4 parts by mass (addition amount corresponding to 0.68 mol / L), it was carried out under the same conditions as in Example 4, and the 50% particle size on the basis of volume distribution of resin fine particles was 0.21 μm. An aqueous dispersion 33 of resin fine particles having a coefficient of variation of 33% was obtained.

[Comparative Example 14]
Emulsification was carried out in the same manner as in Example 4 except that the addition amount of sodium chloride was 6.2 parts by mass (the addition amount corresponding to 0.78 mol / L, exceeding the critical aggregation concentration in this emulsification condition). An aqueous dispersion 34 was obtained. The resin fine particles obtained had a 50% particle size of 0.39 μm based on volume distribution and a coefficient of variation of 119%.

Example 21
Except that the heating shearing time was set to 15 minutes, it was carried out under the same conditions as in Example 2, and the aqueous dispersion of resin fine particles having a 50% particle size of 0.21 μm and a coefficient of variation of 45% based on the volume distribution of resin fine particles 35 was obtained. In addition, when the critical aggregation concentration in the said emulsification conditions was measured separately, the critical aggregation concentration was 0.69 mol / L.

[Comparative Example 15]
Emulsification was carried out in the same manner as in Example 21 except that sodium chloride was not added, to obtain an aqueous dispersion 36 of resin fine particles. The resin fine particles obtained had a 50% particle size of 0.35 μm based on volume distribution and a coefficient of variation of 126%.

[Example 22]
Except that the heating shear time was set to 20 minutes, the same procedure as in Example 2 was carried out, and an aqueous dispersion of resin fine particles having a 50% particle diameter of 0.22 μm and a coefficient of variation of 48% based on the volume distribution of the resin fine particles. 37 was obtained. In addition, when the critical aggregation concentration in the said emulsification conditions was measured separately, the critical aggregation concentration was 0.70 mol / L.

[Comparative Example 16]
Emulsification was performed in the same manner as in Example 22 except that sodium chloride was not added, to obtain an aqueous dispersion 38 of resin fine particles. The resin fine particles obtained had a 50% particle size of 0.36 μm based on volume distribution and a coefficient of variation of 131%.

Example 23
The anionic surfactant was used under the same conditions as in Example 2 except that Nonsar LN-1 (manufactured by NOF Corporation) was 21.6 parts by mass, and the 50% particle size based on the volume distribution of the resin fine particles was 0. An aqueous dispersion 39 of resin fine particles having a diameter of 20 μm and a variation coefficient of 40% was obtained. In addition, when the critical aggregation concentration in the said emulsification conditions was measured separately, the critical aggregation concentration was 0.71 mol / L.

[Comparative Example 17]
Emulsification was carried out in the same manner as in Example 23 except that sodium chloride was not added, to obtain an aqueous dispersion 40 of resin fine particles. The resin fine particles obtained had a 50% particle size of 0.30 μm based on volume distribution and a coefficient of variation of 108%.

Example 24
Except that sodium chloride was changed to 1.1 parts by mass of potassium chloride (addition amount corresponding to 0.10 mol / L), it was carried out under the same conditions as in Example 2, and the 50% particle size on the basis of volume distribution of resin fine particles was 0. An aqueous dispersion 41 of resin fine particles having a diameter of .23 μm and a variation coefficient of 41% was obtained. In addition, when the critical aggregation concentration in the said emulsification conditions was measured separately, the critical aggregation concentration was 0.74 mol / L.

Example 25
Except that sodium chloride was changed to 0.60 part by mass of lithium chloride (addition amount corresponding to 0.10 mol / L), it was performed under the same conditions as in Example 2, and the 50% particle size based on the volume distribution of the resin fine particles was 0. An aqueous dispersion 42 of resin fine particles having a .18 μm and a variation coefficient of 37% was obtained. In addition, when the critical aggregation concentration in the said emulsification conditions was measured separately, the critical aggregation concentration was 0.65 mol / L.

Example 26
Except that sodium chloride was changed to 0.014 part by mass of magnesium chloride (addition amount corresponding to 0.001 mol / L), it was performed under the same conditions as in Example 2, and the 50% particle size on the basis of volume distribution of resin fine particles was 0. An aqueous dispersion 43 of resin fine particles having a .32 μm and a variation coefficient of 86% was obtained. Resin fine particles having a smaller particle diameter and a narrower particle size distribution than the aqueous dispersion 4 to which no salt was added were obtained. In addition, when the critical aggregation concentration in the said emulsification conditions was measured separately, the critical aggregation concentration was 0.011 mol / L.

Example 27
Except that sodium chloride was changed to 0.068 parts by mass of magnesium chloride (addition amount corresponding to 0.005 mol / L), it was performed under the same conditions as in Example 2, and the 50% particle size based on the volume distribution of the resin fine particles was 0. An aqueous dispersion 44 of resin fine particles having a coefficient of variation of 35% was obtained.

Example 28
Except that sodium chloride was changed to 0.14 parts by mass of magnesium chloride (added amount corresponding to 0.010 mol / L), the same procedure as in Example 2 was performed, and the 50% particle size based on the volume distribution of the resin fine particles was 0. An aqueous dispersion 45 of resin fine particles having a thickness of 30 μm and a variation coefficient of 30% was obtained.

[Comparative Example 18]
Emulsification was carried out in the same manner as in Example 2 except that sodium chloride was used in an amount of 0.21 parts by mass of magnesium chloride (addition amount corresponding to 0.015 mol / L, exceeding the critical coagulation concentration under the emulsification conditions), and aqueous resin fine particles were obtained. Dispersion 46 was obtained. The resin fine particles obtained had a 50% particle size of 0.42 μm based on volume distribution and a variation coefficient of 111%.

Example 29
Except that sodium chloride was changed to 0.002 part by mass of aluminum chloride (addition amount corresponding to 0.0001 mol / L), it was performed under the same conditions as in Example 2, and the 50% particle size based on the volume distribution of the resin fine particles was 0. An aqueous dispersion 47 of resin fine particles having a .32 μm and a variation coefficient of 78% was obtained. Resin fine particles having a smaller particle diameter and a narrower particle size distribution than the aqueous dispersion 4 to which no salt was added were obtained. In addition, when the critical aggregation concentration in the said emulsification conditions was measured separately, the critical aggregation concentration was 0.0012 mol / L.

Example 30
Except that sodium chloride was changed to 0.009 part by mass of aluminum chloride (addition amount corresponding to 0.0005 mol / L), the same conditions as in Example 2 were applied, and the 50% particle size based on the volume distribution of the resin fine particles was 0. An aqueous dispersion 48 of resin fine particles having a coefficient of variation of .31 μm and a coefficient of 32% was obtained.

Example 31
Except that sodium chloride was used in 0.019 parts by mass of aluminum chloride (addition amount corresponding to 0.0010 mol / L), it was carried out under the same conditions as in Example 2, and the 50% particle size on the basis of volume distribution of resin fine particles was 0. An aqueous dispersion 49 of resin fine particles having a diameter of .29 μm and a variation coefficient of 31% was obtained.

[Comparative Example 19]
Emulsification was carried out in the same manner as in Example 2 except that sodium chloride was used in an amount of 0.029 parts by mass of aluminum chloride (addition amount corresponding to 0.0015 mol / L, exceeding the critical coagulation concentration in the emulsification conditions). Dispersion 50 was obtained. The resin fine particles obtained had a 50% particle size of 0.44 μm and a coefficient of variation of 122% based on volume distribution.

[Example 32]
100.0 parts by mass of polyester resin 2, 2.0 parts by mass of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK), 4.70 parts by mass of diethylaminoethanol (Kishida Chemical Co., Ltd.) The mixture was put into a beaker and mixed at 95 ° C. for 120 minutes under stirring at 200 r / min with a Kai-type stirrer. Thereafter, 1.2 parts by mass of sodium chloride (added amount corresponding to 0.10 mol / L) heated to 95 ° C. with stirring at 200 r / min with a Kai-type stirrer while maintaining the temperature was charged with 200. An aqueous solution dissolved in 0 part by mass was added dropwise over 2 hours to obtain an aqueous dispersion 51 of resin fine particles having a 50% particle size of 0.25 μm based on volume distribution and a coefficient of variation of 45%. In addition, when the critical aggregation concentration in the said emulsification conditions was measured separately, the critical aggregation concentration was 0.65 mol / L.

[Comparative Example 20]
Emulsification was carried out in the same manner as in Example 32 except that sodium chloride was not added to obtain an aqueous dispersion 52 of resin fine particles. The resin fine particles thus obtained had a 50% particle size of 0.48 μm and a coefficient of variation of 152% based on volume distribution.

[Comparative Example 21]
Emulsification was carried out in the same manner as in Example 32 except that sodium chloride was used in an amount of 8.4 parts by mass (addition amount corresponding to 0.71 mol / L, exceeding the critical aggregation concentration under the emulsification conditions), and aqueous dispersion of resin fine particles was performed. A body 53 was obtained. The resin fine particles obtained had a 50% particle diameter of 0.53 μm and a coefficient of variation of 160% based on the volume distribution.

Example 33
60 parts by mass of polyester resin 2, 12 parts by mass of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK), 2.8 parts by mass of N, N-diethylaminoethanol, and 200 of tetrahydrofuran (manufactured by Wako Pure Chemical Industries) Part by mass, mixed, dissolved K. The mixture was stirred at room temperature while applying a shearing force at 4,000 r / min using Robomix (manufactured by Primics). Then, while continuing stirring, an aqueous solution in which 1.0 part by mass of sodium chloride (addition amount corresponding to 0.10 mol / L) was dissolved in 177.8 parts by mass of ion-exchanged water was gradually added dropwise. Precipitated. Thereafter, tetrahydrofuran was removed using an evaporator to obtain an aqueous dispersion 54 of resin fine particles having a 50% particle size of 0.08 μm and a coefficient of variation of 25% based on the volume distribution of the resin fine particles. In addition, when the critical aggregation concentration in the said emulsification conditions was measured separately, the critical aggregation concentration was 1.10 mol / L.

[Comparative Example 22]
Emulsification was carried out in the same manner as in Example 33 except that sodium chloride was not added, to obtain an aqueous dispersion 55 of resin fine particles. The obtained resin fine particles had a volume distribution standard 50% particle size of 0.10 μm and a coefficient of variation of 26%.

[Comparative Example 23]
Emulsification was carried out in the same manner as in Example 34 except that 11.5 parts by mass of sodium chloride (addition amount corresponding to 1.15 mol / L, exceeding the critical coagulation concentration in this emulsification condition), and aqueous dispersion of resin fine particles was performed. A body 56 was obtained. The resin fine particles obtained had a 50% particle size of 0.15 μm based on volume distribution and a coefficient of variation of 33%.

  Tables 1 to 3 show materials used in Examples 1 to 33 and Comparative Examples 1 to 23, conditions in the emulsification step, physical properties of the obtained resin fine particles, and the like. From the results of Examples 1 to 33 and Comparative Examples 1 to 23, by adding a water-soluble inorganic salt, the resin fine particles of the aqueous dispersion are made small, and the particle size of the resin fine particles is controlled in a nearly uniform state. It was shown that it can be done.

<Manufacture of agglomerated toner>
Example 34
(Preparation of release agent aqueous dispersion)
・ Ester wax (behenyl behenate, melting point: 75 ° C.) 100 parts by mass ・ Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK) 10 parts by mass ・ Ion-exchanged water 880 parts by mass After charging, while heating to 90 ° C. and circulating with a metering pump, using CLEARMIX W-Motion (M Technique Co., Ltd.), rotor rotation speed 19,000r / min, screen rotation speed 19,000r / The mixture was stirred for 60 minutes and dispersed for 60 minutes. After the dispersion treatment for 60 minutes, the release agent aqueous dispersion is subsequently cooled to 40 ° C. under conditions of a rotor rotation speed of 1,000 r / min, a screen rotation speed of 0 r / min, and a cooling rate of 10 ° C./min. Obtained. When this sample was measured using a dynamic light scattering type particle size distribution analyzer (Nanotrack UPA150: manufactured by Nikkiso Co., Ltd.), the 50% particle size based on volume distribution was 0.15 μm, and the coarseness was 0.8 μm or more. Particles were 0.01 volume% or less.

(Preparation of colorant aqueous dispersion)
-Cyan pigment (CI Pigment Blue 15: 3) 100 parts by mass-Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK) 10 parts by mass-Ion-exchanged water 890 parts by mass The above materials are mixed and a homogenizer (IKA: Ultra Turrax T50) was used for dispersion for 30 minutes at a rotation speed of 24,000 r / min. Thereafter, using a high-pressure impact disperser Nanomizer (manufactured by Yoshida Kikai Kogyo Co., Ltd.), dispersion was performed under a pressure condition of 200 MPa to prepare a colorant aqueous dispersion in which a cyan pigment was dispersed. The 50% particle size based on volume distribution of the colorant (cyan pigment) in the colorant aqueous dispersion was 0.12 μm, and the colorant concentration was 10% by mass.

(Aggregation process)
・ Aqueous dispersion 1 of resin fine particles 1 50 parts by mass ・ Coloring agent aqueous dispersion 10 parts by mass ・ Mold release agent aqueous dispersion 20 parts by mass ・ 1 mass% magnesium sulfate aqueous solution 20 parts by mass ・ Ion-exchanged water 100 parts by mass The components were put into a round stainless steel flask, and mixed and dispersed at 5,000 r / min for 10 minutes using a homogenizer (manufactured by IKA: Ultra Turrax T50). Then, it heated to 48 degreeC, adjusting suitably the rotation speed so that a liquid mixture might be stirred using the stirring blade in the water bath for heating. After maintaining at 48 ° C. for 1 hour, the volume average particle diameter of the formed aggregated particles was measured using a flow type particle image analyzer (manufactured by Sysmex Corporation: FPIA-3000) according to the operation manual of the apparatus. As a result, it was confirmed that aggregated particles having a volume average particle diameter of about 5.1 μm were formed.

(Fusion process)
Thereafter, an aqueous solution in which 2 parts by mass of trisodium citrate was dissolved was added to 38 parts by mass of ion-exchanged water, and then the mixture was heated to 75 ° C. and kept for 2 hours while continuing stirring. The volume average particle diameter and average circularity of the obtained particles were measured using a flow type particle image analyzer (manufactured by Sysmex Corporation: FPIA-3000) according to the operation manual of the apparatus. As a result, it was confirmed that sufficiently fused and united particles having a volume average particle diameter of about 5.4 μm and an average circularity of 0.963 were formed.

(Filtration, washing, drying process)
Then, the obtained liquid was cooled and filtered. The filter cake was sufficiently washed with ion-exchanged water, and dried using a vacuum dryer to obtain toner particles 1.

(Production of toner)
To 100 parts by mass of the toner particles, 1.8 parts by mass of hydrophobized silica fine powder having a specific surface area measured by the BET method of 200 m ² / g is dry-mixed with a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.), and the toner is mixed. It was. Then, the fixing property was evaluated by the following method.

An unfixed toner image (0.6 mg / cm ² ) was formed on plain paper (64 g / m ² ) using a commercially available full color digital copying machine (CLC1100, manufactured by Canon Inc.). Next, a fixing unit removed from a commercially available color laser printer (LBP-5500, manufactured by Canon Inc.) was modified so that the fixing temperature could be adjusted, and a fixing test for an unfixed image was performed using this. At that time, the fixing test was performed under normal temperature and humidity, and the process speed was set to 100 mm / second. Further, the fixing temperature was increased by 10 ° C., and an unfixed image was fixed at each fixing temperature. When the presence or absence of an offset in the fixed image when the unfixed image was fixed was visually confirmed, the fixing temperature range in which no offset occurred was 100 to 130 ° C.

[Comparative Example 24]
A toner particle 2 was obtained in the same manner as in Example 34 except that the aqueous dispersion 1 of resin fine particles was changed to the aqueous dispersion 2. The filtrate in the filtration step became a cloudy liquid due to the release of the release agent dispersion. When the release agent component in the white turbid liquid was analyzed, 35% of the release agent used for the toner particle production flowed out. When a fixing test of the toner particles was performed in the same procedure as in Example 34, the fixing temperature range was 100 to 105 ° C.

Example 35
The steps up to the fusion step were performed under the same conditions as in Example 34, and the attachment step described below was further performed.

(Adhesion process)
After fusing the particles in the same manner as in the fusing step of Example 34, water was put in a water bath while stirring was continued, and the core particles were cooled to 25 ° C. Next, 7.7 parts by mass of the aqueous dispersion 3 of resin fine particles was added. The addition amount of the aqueous dispersion 3 of resin fine particles is assumed to be an amount necessary for covering the 5.5 μm core particles with one layer of 0.20 μm shell particles, assuming that the core particles are spherical particles. .

  Then, it stirred for 10 minutes, and also 60 mass parts of 2 mass% calcium chloride aqueous solution was dripped, and it heated up at 35 degreeC. In this state, a small amount of the liquid was extracted at any time, passed through a 2 μm microfilter, and stirring was continued at 35 ° C. until the filtrate became transparent. After confirming that the filtrate became transparent, the mixture was heated to 40 ° C. and stirred for 1 hour, and then 35 parts by mass of a 5 mass% trisodium citrate aqueous solution was added, and the mixture was heated to 65 ° C. and heated to 1.5 Stir for hours.

(Filtration, washing, drying process)
Then, the obtained liquid was cooled and filtered. The filter cake was sufficiently washed with ion-exchanged water, and dried using a vacuum dryer to obtain toner particles 3. The weight average particle diameter (D4) of the toner particles 3 was 5.9 μm.

  Next, when the toner particles were observed with a reflection electron microscope, the core particles were sufficiently covered with the shell particles. The obtained toner particles were stored for 1 week in an environment of a temperature of 40 ° C. and a relative humidity of 80%. As a result, no toner aggregation occurred and the toner had good storage stability. It was shown that.

[Comparative Example 25]
Toner particles 4 were obtained in the same manner as in Example 35 except that the aqueous dispersion 3 of resin fine particles was changed to the aqueous dispersion 4. When the toner particles after drying were observed with a reflection electron microscope, the coating of the shell particles onto the core particles was insufficient. When the obtained toner particles were stored for 1 week in an environment of 40 ° C. and 80% relative humidity, the toner particles began to fuse from the third day and became agglomerated after the fourth day. However, the toner shape could not be maintained.

The aqueous dispersion of resin fine particles obtained by the present invention can be suitably used for the production of electrophotographic toners, inks, paints, adhesives, pressure-sensitive adhesives, fiber processing, papermaking, paper processing and the like.

Claims (9)

Producing an aqueous dispersion of resin fine particles;
An aqueous dispersion of the resin fine particles and a colorant are mixed, and the resin fine particles and the colorant are aggregated in an aqueous medium to obtain an aggregate having a weight average particle diameter (D4) of 4.5 μm or more and 7.0 μm or less. An aggregation process to form;
A fusing step of heating and fusing the aggregates;
In a method for producing a toner having
The step of producing an aqueous dispersion of the resin fine particles includes:
(I) a mixing step of obtaining a mixture by mixing a resin having an acid group, an anionic surfactant, water and a water-soluble inorganic salt;
(Ii) Stirring of the mixture at a temperature equal to or higher than the glass transition temperature of the resin having an acid group, and an aqueous dispersion of the resin fine particles having a 50% particle size based on volume distribution of 0.02 μm to 1.00 μm Having an emulsification step
The water-soluble inorganic salt is sodium chloride, potassium chloride or lithium chloride;
In the emulsification step, a toner production method, wherein the concentration of the water-soluble inorganic salt in the aqueous phase of the aqueous dispersion is not more than the following critical aggregation concentration.
[Critical aggregation concentration is the volume distribution of the resin fine particles in the aqueous dispersion of the resin fine particles before the addition of the water soluble inorganic salt, in which the volume distribution standard 50% particle size of the resin fine particles added with the water-soluble inorganic salt is 50%. This is the concentration of the water-soluble inorganic salt in the aqueous phase of the aqueous dispersion when it exceeds 1.5 times the distribution standard 50% particle size. ] Producing an aqueous dispersion of resin fine particles;
An aqueous dispersion of the resin fine particles and a colorant are mixed, and the resin fine particles and the colorant are aggregated in an aqueous medium to obtain an aggregate having a weight average particle diameter (D4) of 4.5 μm or more and 7.0 μm or less. An aggregation process to form;
A fusing step of heating and fusing the aggregates;
In a method for producing a toner having
The step of producing an aqueous dispersion of the resin fine particles includes:
(I) a mixing step of mixing a resin having an acid group, a solvent in which the resin having an acid group is soluble, and an anionic surfactant to obtain a mixture;
(Ii) An emulsification step of adding a water-soluble inorganic salt and water to the mixture and stirring to obtain an aqueous dispersion of the resin fine particles having a 50% particle size on a volume distribution basis of 0.02 μm to 1.00 μm. The step of producing the aqueous dispersion of the resin fine particles includes
In the emulsification step, a method for producing a toner, wherein the concentration of the water-soluble inorganic salt in the aqueous phase of the aqueous dispersion is not more than the critical aggregation concentration defined below.
[Critical aggregation concentration is the volume distribution of the resin fine particles in the aqueous dispersion of the resin fine particles before the addition of the water soluble inorganic salt, in which the volume distribution standard 50% particle size of the resin fine particles added with the water-soluble inorganic salt is 50%. This is the concentration of the water-soluble inorganic salt in the aqueous phase of the aqueous dispersion when it exceeds 1.5 times the distribution standard 50% particle size. ] The toner production method according to claim 2 , wherein the water-soluble inorganic salt is a monovalent salt. The toner production method according to claim 3 , wherein the monovalent salt is sodium chloride, potassium chloride, or lithium chloride. The glass transition point of the resin having an acid group, method for producing a toner according to any one of claims 1-4 is 80 ° C. less than 50 ° C.. Said resin having an acid group, method for producing a toner according to any one of claims 1 to 5 which is a hydrolyzable resin.   The toner manufacturing method according to claim 6, wherein a basic substance is added in the emulsification step. Resins having an acid group, method for producing a toner according to any one of claims 1 to 7 which is a polyester resin. The acid value of the resin having the acid group, method for producing a toner according to any one of claims 1-8 is 1 mgKOH / g or more 30 mgKOH / g or less.