JP5418396B2 - Method for producing toner for developing electrostatic image - Google Patents

Description

  The present invention relates to a method for producing an electrostatic charge image developing toner (hereinafter, also simply referred to as “toner”) used for electrophotographic image formation.

  In recent years, from the viewpoint of global warming prevention, energy saving has been studied in various fields, and efforts have been made to use low energy, such as power saving during standby, in information devices such as image forming apparatuses. On the other hand, studies have been made to lower the fixing temperature in the fixing process that consumes the most energy.

  In general, when toner particles are designed to support low-temperature fixing, the toner is inferior in blocking resistance (heat-resistant storage property), but in order to achieve both low-temperature fixing properties and blocking resistance, for example, Patent Document 1 describes: Disclosed is a pulverized toner obtained by dispersing a rubber-like substance in a binder resin by kneading and then pulverizing the kneaded product as a technique for achieving both low-temperature fixability and anti-blocking property for toner used for electrophotographic image formation. Has been.

  However, the kneaded material in which the rubber-like substance is dispersed has a very low grindability because the rubber-like substance absorbs an impact force applied at the time of crushing, so that the productivity is low and the mass production is realistic. There wasn't.

For example, in Patent Document 2, a styrene-diene block copolymer is added to a styrene-acrylic resin as a main resin as a technique for achieving both low-temperature fixability, heat-resistant storage stability, and blocking resistance. A suspension polymerized toner containing a binder resin is disclosed.
According to such a toner, the blocking effect can be improved without increasing the fixing temperature by applying the effect that the styrene-diene block copolymer encapsulates the wax in the granulation process in the toner particles. It is supposed to be possible.

However, in the production process of the suspension polymerization toner, the polymerizable monomer liquid containing the styrene-diene block copolymer is mechanically divided by a mixer in the reaction apparatus to form droplets, and emulsion polymerization is performed. Since the polymerization reaction takes a long time compared to the above, the reaction residue derived from the styrene-diene block copolymer, that is, the toner particles are not formed into toner particles, but the foreign matter adhered and deposited on the inner wall of the reaction apparatus is mixed into the toner. There was a problem. When toner composed of toner particles mixed with reaction residue is used, white spots of image defects due to omission of transfer occur in the obtained image.
Usually, such a reaction residue can be removed by adding a coarse powder classification process using an airflow classifier after toner particles are formed, but the productivity is greatly reduced by adding an extra process, There is a problem that it is not suitable for industrial mass production, and there is a large variation in production time due to batches, and when a dispersion of toner particles is transferred from a reactor related to polymerization to a reactor related to the next process. However, there is a problem that high production stability cannot be obtained because the reaction residue is clogged in the strainer installed in the meantime and the production line is frequently stopped temporarily.

JP-A-8-305079 JP-A-7-181740

  The present invention has been made in consideration of the circumstances as described above, and its purpose is to obtain low-temperature fixability while basically obtaining blocking resistance, and excellent high-temperature offset resistance and Another object of the present invention is to provide a method for producing a toner for developing an electrostatic charge image, which has crease fixability and has productivity and production stability suitable for industrial mass production.

The method for producing a toner for developing an electrostatic charge image of the present invention comprises a first resin having a glass transition point (Tg) of 33 ° C. to 58 ° C., and a styrene having a glass transition point (Tg) of −70 ° C. to + 30 ° C. A method for producing a toner for developing an electrostatic image comprising toner particles containing a second resin comprising a diene copolymer and a colorant,
A dispersion liquid (A) in which first resin fine particles having a volume-based median diameter of 75 to 300 nm are dispersed in an aqueous medium;
A dispersion liquid (B) in which second resin fine particles having a volume-based median diameter of 75 to 250 nm are dispersed in an aqueous medium,
After mixing the dispersion liquid (C) in which the fine particles of the colorant are dispersed in an aqueous medium, the toner particles are formed by aggregating the first resin fine particles, the second resin fine particles, and the colorant fine particles. It is characterized by undergoing a forming step.

  In the method for producing the toner for developing an electrostatic charge image of the present invention, the content of the second resin is preferably 2 to 15% by mass of the total of the first resin and the second resin.

  In the method for producing a toner for developing an electrostatic image according to the present invention, the second resin constituting the second resin fine particles in the dispersion (B) is a carboxy-modified styrene-diene copolymer. preferable.

  Furthermore, in the method for producing a toner for developing an electrostatic charge image of the present invention, the styrene-diene copolymer constituting the second resin is preferably a styrene-butadiene copolymer.

  According to the method for producing a toner for developing an electrostatic charge image of the present invention, a low temperature fixability is obtained while blocking resistance is obtained by containing a specific styrene-diene copolymer. It is possible to produce a toner that exhibits the elasticity due to the styrene-diene copolymer effectively and can obtain excellent high temperature offset resistance and crease fixability.

The reason why the elasticity by the specific styrene-diene copolymer is effectively exhibited in the obtained toner is presumed as follows.
That is, according to the production method of the present invention, the glass transition point (Tg) of the second resin by the first resin and the specific styrene-diene copolymer is set to a specific range, respectively, and the first The styrene-diene copolymer is obtained by agglomerating the first resin fine particles by the resin and the second resin fine particles by the second resin in a state where the volume-based median diameters are set in specific ranges, respectively. However, it is presumed that a toner having a specific size domain formed in the first resin can be obtained. The domain of the rubber component styrene-diene copolymer is finely dispersed in a specific size, thereby increasing the contact area with the first resin as the matrix. As a result, the specific styrene- It is considered that the elasticity of the diene copolymer is effectively exhibited.

  According to the method for producing a toner for developing an electrostatic charge image of the present invention, the dispersion stability is high due to the action of the charge of the second resin fine particles composed of the second resin by the specific styrene-diene copolymer. Since the toner particles grow up to the intended diameter while the second resin fine particles are taken into the first resin, the generation of the reaction residue does not affect the production stability. Instead of the first resin and the second resin, it can be suppressed to the same level as when toner particles are produced using only the first resin.

  Hereinafter, the present invention will be specifically described.

[Toner Production Method]
The toner manufacturing method of the present invention includes a first resin (hereinafter also referred to as “main resin”) having a glass transition point (Tg) of 33 ° C. to 58 ° C., which mainly constitutes a binder resin. From toner particles containing a second resin (hereinafter also referred to as “sub-resin”) made of a specific styrene-diene copolymer having a glass transition point (Tg) of −70 ° C. to + 30 ° C. and a colorant. And a method using an emulsion polymerization association method.
This sub-resin constitutes a part of the binder resin, and also functions as a fixing modifier for the main resin.

  Specifically, the toner production method of the present invention includes a dispersion liquid (A) in which main resin fine particles having a volume-based median diameter of 75 to 300 nm made of a main resin are dispersed in an aqueous medium, and an aqueous medium. A dispersion (B) in which sub-resin fine particles having a volume-based median diameter of 75 to 250 nm are dispersed therein, and a dispersion (C) in which colorant fine particles are dispersed in an aqueous medium. After mixing, the main resin fine particles, sub resin fine particles and colorant fine particles are aggregated to form a toner particle.

  In this emulsion polymerization association method, main resin fine particles, sub resin fine particles, and colorant fine particles are slowly aggregated while balancing the repulsive force on the surface of the fine particles by pH adjustment and the cohesive force by adding an aggregating agent made of an electrolyte. In this method, toner particles are produced by performing association while controlling the average particle size and particle size distribution, and simultaneously performing shape control by fusing the fine particles by heating and stirring.

An example of a method for producing the toner of the present invention is specifically shown as follows:
(1) A main resin fine particle dispersion preparing step for preparing a dispersion (A) in which main resin fine particles having a volume-based median diameter of 75 to 300 nm made of a main resin are dispersed in an aqueous medium.
(2) A sub-resin fine particle dispersion preparing step of preparing a dispersion (B) in which sub-resin fine particles having a volume-based median diameter of 75 to 250 nm are dispersed in an aqueous medium.
(3) A colorant fine particle dispersion preparing step for preparing a dispersion (C) in which colorant fine particles are dispersed in an aqueous medium.
(4) A dispersion mixing step of mixing the dispersions (A) to (C).
(5) A salting-out, agglomeration, and fusing step in which toner particles are formed by salting out, agglomerating, and fusing main resin fine particles, sub-resin fine particles, and colorant fine particles in an aqueous medium.
(6) A filtration and washing step for separating the toner particles from the toner particle dispersion (aqueous medium) and removing the surfactant from the toner particles.
(7) A drying step of drying the washed toner particles.
Consisting of, if necessary,
(8) An external additive addition step of adding an external additive to the dried toner particles.
Can be added.

  In the present invention, the “aqueous medium” refers to a medium comprising 50 to 100% by mass of water and 0 to 50% by mass of a water-soluble organic solvent. Examples of the water-soluble organic solvent include methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, and tetrahydrofuran, and alcohol-based organic solvents that do not dissolve the resulting resin are preferable.

<Step (1): Main resin fine particle dispersion preparation step>
The main resin fine particles in the dispersion (A) are preferably produced by an emulsion polymerization method.
In the emulsion polymerization method, the polymerizable monomer to form the main resin is dispersed in an aqueous medium to form emulsion particles (oil droplets), and then a polymerization initiator is added to polymerize the polymerizable monomer. By doing so, main resin fine particles are formed.

[Main resin]
The main resin is a resin having a glass transition point (Tg) of 33 ° C. to 58 ° C., and specifically, a styrene-acrylic resin or a polyester resin is preferable.
As the styrene-acrylic resin, a random copolymer of a polymerizable monomer containing at least a styrene monomer and an acrylic acid monomer is preferable.

  When the glass transition point (Tg) of the main resin is in the above range, it is possible to perform particle size growth with a good balance between the sub resin fine particles and the main resin fine particles when the fine particles are aggregated. On the other hand, when the glass transition point (Tg) of the main resin is too small, the obtained toner does not have sufficient blocking resistance, and the toner easily aggregates during storage. When the glass transition point (Tg) of the toner is excessive, the obtained toner does not have sufficient low-temperature fixability.

The glass transition point (Tg) of the main resin can be measured using a differential scanning calorimeter “DSC8500” (manufactured by PerkinElmer).
Specifically, 4.5 mg of dried main resin fine particles are precisely weighed to two digits after the decimal point, sealed in an aluminum pan, and set in a sample holder. For the reference, an empty aluminum pan was used, and heat-cool-heat temperature control was performed at a measurement temperature of 0 to 200 ° C., a temperature increase rate of 10 ° C./min, and a temperature decrease rate of 10 ° C./min. Analysis is performed based on the data in Heat. The glass transition point is the value of the intersection of the baseline extension before the first endothermic peak rises and the tangent line that shows the maximum slope between the first endothermic peak rising portion and the peak apex.

As the polymerizable monomer to form the main resin, for example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methyl can be used as the styrene monomer for forming the styrene-acrylic resin. Styrene, p-phenyl styrene, p-ethyl styrene, 2,4-dimethyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn -Styrene such as decylstyrene or pn-dodecylstyrene or a styrene-styrene derivative. These can be used alone or in combination of two or more.
Further, as an acrylic acid monomer for forming a styrene-acrylic resin, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-methacrylic acid n- Methacrylate derivatives such as octyl, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate; methyl acrylate, ethyl acrylate, isopropyl acrylate, acrylic N-butyl acid, t-butyl acrylate, isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, acrylic Acrylic acid ester derivatives such as acid phenyl and the like. These can be used alone or in combination of two or more.
When a styrene-butyl acrylate copolymer is used as the main resin, the preferred copolymerization ratio of styrene and butyl acrylate is 65:35 to 85:15 on a mass basis from the viewpoint of heat-resistant storage stability.
When a styrene-butyl acrylate copolymer is used as the main resin, it is particularly preferable that the styrene-butyl acrylate copolymer is a terpolymer in which (meth) acrylic acid is also copolymerized. In this case, it is preferable that the copolymerization ratio of the (meth) acrylic acid is 2.0 to 8.0% by mass from the viewpoint of adjusting the aggregation rate with the sub resin and suppressing the release of the sub resin fine particles.

Further, as the polyvalent carboxylic acid for forming the polyester resin, a divalent or higher carboxylic acid such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid , Maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, n-dodecyl succinic acid, n-dodecenyl succinic acid, isododecyl succinic acid, isododecenyl succinic acid, n-octyl succinic acid, n-octenyl succinic acid, etc. Dicarboxylic acids of the above; aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid; trimellitic acid, pyromellitic acid, their acid anhydrides, or trivalent or higher carboxylic acids such as acid chlorides, etc. Can be mentioned. These can be used alone or in combination of two or more.
Further, as a polyhydric alcohol for forming a polyester resin, a dihydric or higher alcohol such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butane. Diol, 1,4-butylene diol, neopentyl glycol, 1,5-pentane glycol, 1,6-hexane glycol, 1,7-heptane glycol, 1,8-octanediol, 1,9-nonanediol, 1, 10-decanediol, pinacol, cyclopentane-1,2-diol, cyclohexane-1,4-diol, cyclohexane-1,2-diol, cyclohexane-1,4-dimethanol, dipropylene glycol, polyethylene glycol, polypropylene group Diols such as coal, polytetramethylene glycol, bisphenol A, bisphenol Z, hydrogenated bisphenol A; trivalents such as glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, trisphenol PA, phenol novolac, cresol novolac Examples thereof include the above polyhydric aliphatic alcohols; and alkylene oxide adducts of the above trivalent or higher polyhydric aliphatic alcohols. These can be used alone or in combination of two or more.

(Polymerization initiator)
As a polymerization initiator used in the main resin fine particle dispersion preparation step, any water-soluble polymerization initiator can be used. As specific examples of the polymerization initiator, for example, persulfates (potassium persulfate, ammonium persulfate, etc.) are preferably used. In addition, azo compounds (such as 4,4′-azobis-4-cyanovaleric acid and salts thereof, 2,2′-azobis (2-amidinopropane) salt), peroxide compounds, and the like may be used.

[Chain transfer agent]
In the main resin fine particle dispersion preparing step, a generally used chain transfer agent can be used for the purpose of adjusting the molecular weight of the main resin. The chain transfer agent is not particularly limited, and examples thereof include mercaptans such as 2-chloroethanol, octyl mercaptan, dodecyl mercaptan, and t-dodecyl mercaptan, and styrene dimers.

  If the glass transition point (Tg) is 33 ° C. to 58 ° C., the main resin fine particles can have a structure of two or more layers made of resins having different compositions. It is possible to employ a method in which a polymerization initiator and a polymerizable monomer are added to a dispersion of resin fine particles prepared by the first stage polymerization), and this system is polymerized (second stage polymerization).

The average particle diameter of the main resin fine particles in the dispersion (A) obtained in the main resin fine particle dispersion preparing step is in a range of 75 to 300 nm in terms of volume-based median diameter.
The volume-based median diameter of the main resin fine particles is measured using “Microtrac UPA-150” (manufactured by Nikkiso Co., Ltd.).
Specifically, first, several drops of main resin fine particles for measurement are dropped into a 50 ml measuring cylinder, 25 ml of pure water is added thereto, and an ultrasonic cleaner “US-1” (manufactured by asone) is used. A sample for measurement is prepared by dispersing for 3 minutes. Next, 3 mL of the measurement sample was put into a cell of “Microtrac UPA-150” (manufactured by Nikkiso Co., Ltd.), and after confirming that the value of Sample / Loading was in the range of 0.1 to 100, Measurement is performed according to the measurement conditions and solvent conditions.
-Measurement conditions-
・ Transparency (transparency): Yes
-Refractive Index (refractive index): 1.59
・ Particle Density (particle density): 1.05 g / cm ³
・ Spherical Particles (spherical particles): Yes
-Solvent conditions-
-Refractive Index (refractive index): 1.33
・ Viscosity:
High (temp) 0.797 × 10 ⁻³ Pa · s
Low (temp) 1.002 × 10 ⁻³ Pa · s

  Since the volume-based median diameter of the main resin fine particles is within the above range, the particle size growth can be performed with a good balance between the sub resin fine particles and the main resin fine particles when the fine particles are aggregated, and reaction residue is generated. Can be suppressed. On the other hand, if the volume-based median diameter of the main resin fine particles is too small, it takes an excessive amount of time for the fine particles to aggregate. In addition, when the volume-based median diameter of the main resin fine particles is excessive, it is not possible to form domains due to the sub resin fine particles with sufficient dispersibility, and as a result, a toner that does not effectively exhibit the elasticity due to the sub resin. And the generation of reaction residues is increased.

<Step (2): Sub-resin fine particle dispersion preparation step>
The sub-resin fine particles in the dispersion (B) are preferably produced by an emulsion polymerization method.
In the emulsion polymerization method, a polymerizable monomer to form a sub-resin is dispersed in an aqueous medium to form emulsion particles (oil droplets), and then a polymerization initiator is added to polymerize the polymerizable monomer. By doing so, sub-resin fine particles are formed.

[Sub resin]
The sub-resin according to the present invention is a rubber component and acts as an adhesive for the main resin in the toner particles. Specifically, it acts as an adhesive between the main resins after fixing, and as a result, the fixed image has high strength against deformation of the fixed image, and the fixed image has high strength. It has fixing properties.

The sub-resin according to the present invention is a styrene-diene copolymer having a specific glass transition point (Tg).
Examples of the styrene monomer for obtaining the styrene-diene copolymer include styrene and styrene having a substituent, and examples of the diene monomer include butadiene and isoprene.
It is preferable that the copolymerization ratio of a styrene-type monomer is 10-50 mass%, Most preferably, it is 30-50 mass%.
The styrene-diene copolymer constituting the sub-resin fine particles is particularly preferably a styrene-butadiene copolymer. The reason why the styrene-butadiene copolymer is preferable to the styrene-isoprene copolymer is that the intermolecular distance is small as long as it does not have a methyl group related to isoprene, which contributes to the improvement of the strength of the fixed image. This is presumably because a better crease fixability can be obtained.

  The styrene-diene copolymer constituting the sub-resin fine particles is not limited as long as it is a copolymer obtained from a styrene monomer and a diene monomer. It is preferably a random copolymer of styrene-butadiene crosslinked with an unsaturated polyvalent carboxylic acid.

The styrene-diene copolymer constituting the sub-resin fine particles is preferably a carboxy-modified styrene-diene copolymer.
A carboxy-modified styrene-diene copolymer, that is, a carboxy-modified styrene-diene copolymer is dissociated by using an acid monomer as a polymerizable monomer to form a styrene-diene copolymer. A carboxyl group which is a functional group is introduced. By using a carboxy-modified styrene-diene copolymer, the sub-resin fine particles can be stably dispersed in the aggregated system.
A styrene-butadiene random copolymer crosslinked with an unsaturated polyvalent carboxylic acid such as maleic acid is also preferably used as a carboxy-modified styrene-diene copolymer.
The styrene-diene copolymer constituting the sub-resin is particularly preferably one having a carboxy modification degree equivalent to that of the main resin. By using such a carboxy-modified styrene-diene copolymer, the behavior of the sub resin fine particles, the main resin fine particles, and the aggregation speed becomes the same when the fine particles are aggregated. Therefore, the generation of reaction residues can be suppressed.

Specific examples of the acid monomer for obtaining a carboxy-modified styrene-diene copolymer include unsaturated monovalent carboxylic acids such as acrylic acid, methacrylic acid, and cinnamic acid; maleic acid, fumaric acid, and itacon. Unsaturation such as acid, citraconic acid, glutaconic acid, tetrahydrophthalic acid, aconitic acid, maleic anhydride, itaconic anhydride, glutaconic anhydride, citraconic anhydride, aconitic anhydride, norbornene dicarboxylic acid anhydride, tetrahydrophthalic anhydride And polyvalent carboxylic acid. These can be used alone or in combination of two or more.
The copolymerization ratio of the acid monomer is preferably, for example, 1.0 to 2.0% by mass.

The glass transition point (Tg) of the sub-resin according to the present invention is −70 ° C. to + 30 ° C., preferably −30 ° C. to + 20 ° C.
When the glass transition point (Tg) of the sub-resin is less than −70 ° C., the aggregation of only the sub-resin fine particles starts at a temperature of about 70 to 80 ° C. during the temperature rising process during the aggregation of the fine particles. If the particle size growth is not performed with a good balance between the fine particles and the main resin fine particles, and the glass transition point (Tg) of the sub resin exceeds + 30 ° C., the obtained toner has sufficient low-temperature fixability. There is a risk of not becoming.
The glass transition point (Tg) of the sub resin is measured by the same method as the measurement of the glass transition point (Tg) of the main resin described above using the measurement sample as the sub resin.

The sub-resin preferably has a toluene-insoluble content of 70 to 90% by mass.
By having such a high toluene-insoluble content (gel content), domains of an appropriate size are formed by the sub-resin in the obtained toner particles, and the elasticity and low glass transition point of the sub-resin are reflected in the toner particles. It is assumed that it will be easier.
The toluene-insoluble matter of the sub-resin is obtained by immersing a predetermined amount (about 0.03 g) of the sample in a predetermined amount (about 100 mL) of toluene at 20 ° C. for 20 hours, and then filtering with a 120-mesh wire mesh, It is calculated by the mass% with respect to the sample of the minute.

Examples of the polymerization initiator used in the sub-resin fine particle dispersion preparation step include the same ones that can be used in the main resin fine particle dispersion preparation step.
Moreover, when using a chain transfer agent in a sub resin fine particle dispersion preparation process, as a chain transfer agent, the thing similar to what can be used in a main resin fine particle dispersion preparation process can be mentioned.

The average particle diameter of the sub-resin fine particles in the dispersion liquid (B) obtained in the sub-resin fine particle dispersion preparation step is in the range of 75 to 250 nm as a volume-based median diameter.
The volume-based median diameter of the sub resin fine particles is measured as described above using the sub resin fine particles as a measurement sample.

When the volume-based median diameter of the sub-resin fine particles is in the above-described range, it is possible to perform particle size growth with a good balance between the sub-resin fine particles and the main resin fine particles when the fine particles are aggregated. In addition, it is thought that a domain is formed by one to plural sub-resin fine particles.
On the other hand, when the volume-based median diameter of the sub-resin fine particles is too small, the domain due to the sub-resin fine particles cannot be made sufficiently large, and as a result, the toner that does not effectively exhibit the elasticity due to the sub-resin If the volume-based median diameter of the sub-resin fine particles is excessive, the domains due to the sub-resin fine particles become excessively large, resulting in sufficient blocking resistance. Inadequate toner may be produced.

In the toner according to the present invention, the content of the sub resin is preferably 2 to 15% by mass of the total of the main resin and the sub resin, more preferably 2 to 10% by mass, and further preferably 2 to 5% by mass. Especially preferably, it is 3 mass%.
When the content of the sub-resin is in the above extremely small range, the blocking resistance is sufficiently obtained while the low-temperature fixability is obtained. On the other hand, when the content of the sub-resin is excessive, sufficient blocking resistance cannot be obtained, and the generation of reaction residues during production is increased. Further, when the content of the sub-resin is too small, sufficient low-temperature fixability cannot be obtained, sufficient crease fixability cannot be obtained, and a high-temperature offset phenomenon may occur.

<Process (3) Colorant fine particle dispersion preparation process>
The average particle diameter of the colorant fine particles obtained in the colorant fine particle dispersion preparing step is preferably in the range of, for example, 10 to 300 nm as a volume-based median diameter. The volume-based median diameter is measured as described above using fine colorant particles as a measurement sample.

[Colorant]
As the colorant contained in the toner according to the present invention, generally known dyes and pigments can be used.
As a colorant for obtaining a black toner, various known ones such as carbon black, a magnetic material, a dye, and an inorganic pigment containing nonmagnetic iron oxide can be arbitrarily used.
As the colorant for obtaining a color toner, known ones such as dyes and organic pigments can be arbitrarily used.
The colorant for obtaining the toner of each color can be used alone or in combination of two or more for each color.

  The content ratio of the colorant is preferably 1 to 10% by mass in the toner, and more preferably 2 to 8% by mass. When the content of the colorant is less than 1% by mass in the toner, the obtained toner may be insufficient in coloring power, while the content of the colorant exceeds 10% by mass in the toner. In some cases, the colorant is liberated or adhered to the carrier, which may affect the chargeability.

In addition to the main resin, sub resin, and colorant, the toner particles according to the present invention may contain an internal additive such as a release agent or a charge control agent, if necessary. For example, before the step (4), the additive is prepared as a dispersion of fine particles of the internal additive consisting of only the internal additive. In the step (4), the fine particles of the internal additive fine particles together with the dispersions (A) to (C) are prepared. The dispersion liquid is mixed, and the internal additive fine particles are aggregated together with the main resin fine particles, the sub resin fine particles, and the colorant fine particles in the step (5), and can be introduced into the toner particles.
Further, for example, in the step (1), the main resin fine particles can be introduced into the toner particles by using the main resin and the internal additive mixed at the molecular level. The main resin fine particles in which the main resin and the internal additive are mixed at the molecular level are prepared by dissolving the internal additive in advance in the polymerizable monomer that should form the main resin, and the polymerizable resin containing the internal additive. It can be produced by polymerizing the monomer.

〔Release agent〕
The release agent is not particularly limited. For example, polyethylene wax, oxidized polyethylene wax, polypropylene wax, oxidized polypropylene wax, carnauba wax, paraffin wax, microcrystalline wax, Fischer-Tropsch wax, rice wax, Candelilla wax can be used.
The content ratio of the release agent in the toner particles is usually 0.5 to 25 parts by mass, preferably 3 to 15 parts by mass with respect to 100 parts by mass of the binder resin.

[Charge control agent]
Various known compounds can be used as the charge control agent.
The content ratio of the charge control agent in the toner particles is usually 0.1 to 10 parts by mass, preferably 0.5 to 5 parts by mass with respect to 100 parts by mass in total of the main resin and the sub resin.

<Step (4): Dispersion mixing step>
In this dispersion liquid mixing step, in the state where the dispersion liquid (A) of the main resin fine particles is adjusted to a weak alkalinity of, for example, pH 7.5 to 11, the sub resin fine particles are added to the dispersion liquid (A) of the main resin fine particles. It is preferable to add the dispersion (B). In particular, when the sub-resin fine particles are made of a carboxy-modified styrene-diene copolymer, this is preferable.
By adding the dispersion liquid (B) of the sub-resin fine particles to the agglomerated system adjusted to weak alkalinity, the carboxyl group in the carboxy-modified styrene-diene copolymer constituting the sub-resin fine particles in neutral to weak alkalinity is reduced. Since the ionized state is obtained and the dispersion stability of the sub-resin fine particles is high, the domain of the sub-resin fine particles can be formed with the desired dispersibility. Note that when the dispersion liquid (B) of the sub resin fine particles is added to, for example, an acidic system, the aggregation of the sub resin fine particles starts in a state where the coagulant is not added and / or in a state where the temperature is not raised. Moreover, when the dispersion liquid (B) of sub resin fine particles is added to, for example, a strongly alkaline system, the carboxyl group is hydrolyzed.

Moreover, in this dispersion liquid mixing process, it is preferable that the temperature of the aggregation system at the time of addition of the dispersion liquid (B) of sub resin fine particles is maintained at 5-30 degreeC.
By maintaining the agglomeration system at such a temperature, even if the sub-resin fine particles come into contact with the reaction apparatus, adhesion hardly occurs, and the dispersion stability is high due to the charge of the sub-resin fine particles. It is presumed that the occurrence of the occurrence can be suppressed.

In this dispersion liquid mixing step, a surfactant may be added in order to stably disperse each fine particle in the aggregation system.
The surfactant is preferably added to the aggregation system after the addition of the main resin fine particles and the sub resin fine particles because the surfactant molecules can easily act on both the main resin fine particles and the sub resin fine particles.

In the case of using a surfactant in this dispersion mixing step, the surfactant is not particularly limited and various known ones can be used. Sodium dodecylbenzenesulfonate, sodium arylalkylpolyethersulfonate Sulfates such as sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate; sodium oleate, sodium laurate, sodium caprate, sodium caprylate, sodium caproate, potassium stearate An ionic surfactant such as a fatty acid salt such as calcium oleate can be exemplified as a suitable one.
Also, polyethylene oxide, polypropylene oxide, combination of polypropylene oxide and polyethylene oxide, ester of polyethylene glycol and higher fatty acid, alkylphenol polyethylene oxide, ester of higher fatty acid and polyethylene glycol, ester of higher fatty acid and propylenoxide, sorbitan ester Nonionic surfactants such as can also be used.
The above surfactants can be used alone or in combination of two or more as desired.

<Process (5): Salting-out, aggregation, fusion process>
In this salting-out, agglomeration and fusion process, aggregation is started by adding a flocculant and raising the temperature.

[Flocculant]
Examples of the aggregating agent used in the salting-out, agglomeration, and fusion processes include alkali metal salts and alkaline earth metal salts. Examples of the alkali metal constituting the flocculant include lithium, potassium, and sodium, and examples of the alkaline earth metal constituting the flocculant include magnesium, calcium, strontium, and barium. Of these, potassium, sodium, magnesium, calcium, and barium are preferable. Examples of the counter ion (anion constituting the salt) of the alkali metal or alkaline earth metal include chloride ion, bromide ion, iodide ion, carbonate ion and sulfate ion.

<Step (6): Filtration, washing step to step (8): External additive addition step>
These steps can be performed according to a filtration, washing step, drying step, and external additive addition step in a publicly known emulsion polymerization aggregation method.

[Particle size of toner particles]
The toner particles preferably have a volume-based median diameter of 3 to 9 μm, and more preferably 3 to 8 μm. This particle size can be controlled by the concentration of the coagulant used, the amount of organic solvent added, the fusing time, and the composition of the polymer.
When the volume-based median diameter is in the above range, the transfer efficiency is increased, the image quality of halftone is improved, and the image quality of fine lines and dots is improved.

  The volume-based median diameter of toner particles is measured and calculated using a measuring device in which a computer system equipped with data processing software “Software V3.51” is connected to “Coulter Multisizer 3” (manufactured by Beckman Coulter). It is what is done. Specifically, 0.02 g of toner is added to 20 mL of a surfactant solution (for example, a surfactant solution obtained by diluting a neutral detergent containing a surfactant component 10 times with pure water for the purpose of dispersing toner particles). Then, ultrasonic dispersion is performed for 1 minute to prepare a toner dispersion, and this toner dispersion is placed in a beaker containing “ISOTON II” (manufactured by Beckman Coulter) in a sample stand. Pipet until the indicated concentration is 8%. Here, a reproducible measurement value can be obtained by setting the concentration range. In the measurement apparatus, the measurement particle count is 25000, the aperture diameter is 50 μm, the frequency value is calculated by dividing the measurement range of 1 to 30 μm into 256, and the volume integrated fraction is 50 % Particle diameter is defined as the volume-based median diameter.

[Average circularity of toner particles]
The toner according to the present invention preferably has an average circularity represented by the following formula (T) of 0.930 to 1.000 for the individual toner particles constituting the toner from the viewpoint of improving transfer efficiency. More preferably, it is 0.950-0.995.
Formula (T): Average circularity = circumference of circle determined from equivalent circle diameter / perimeter of particle projection image

The toner as described above preferably has a glass transition point of 90 to 130 ° C, more preferably 100 to 120 ° C.
Furthermore, the softening point temperature is preferably 80 to 110 ° C, more preferably 90 to 105 ° C.

The glass transition point (Tg) of the toner is measured by the same method as described above using the measurement sample as the toner.
Further, the softening point temperature of the toner is measured as follows.
First, 20 ° C., in an environment of 50% RH, flattened out put toner 1.1g in a Petri dish and allowed to stand for 12 hours or more, molding machine "SSP-10A" 3820kg by (Shimadzu) / cm ² A cylindrical molded sample with a diameter of 1 cm is prepared by applying pressure for 30 seconds, and then this molded sample is subjected to a flow tester “CFT-500D” (manufactured by Shimadzu Corporation) in an environment of 24 ° C. and 50% RH. With a load of 196 N (20 kgf), a starting temperature of 60 ° C., a preheating time of 300 seconds, and a heating rate of 6 ° C./min, preheating is performed using a 1 cm diameter piston from a hole (1 mm diameter × 1 mm) of a cylindrical die. The offset method temperature T _{offset, which} is extruded from the end and measured by the melting temperature measurement method of the temperature raising method with an offset value of 5 mm, is set as the softening point temperature of the toner.

  When the glass transition point of the toner is too low, the toner does not have sufficient blocking resistance, and the toner easily aggregates during storage. On the other hand, when the glass transition point is excessively high, it is difficult to melt and fix. In addition, the color reproducibility is low and sufficient color reproducibility cannot be obtained in a full-color image formed without obtaining sufficient color mixing. Further, when the softening point temperature of the toner is excessively low, a high temperature offset phenomenon is likely to occur in the fixing step, whereas when the softening point temperature is excessively high, sufficient fixing strength cannot be obtained.

(External additive)
The above toner particles can be used as toners as they are, but in order to improve fluidity, chargeability, cleaning properties, etc., external additives such as fluidizing agents and cleaning aids are added to the toner particles. You may use it in the state.
Examples of the fluidizing agent include silica, alumina, titanium oxide, zinc oxide, iron oxide, copper oxide, lead oxide, antimony oxide, yttrium oxide, magnesium oxide, barium titanate, ferrite, bengara, magnesium fluoride, silicon carbide. Inorganic fine particles made of boron carbide, silicon nitride, zirconium nitride, magnetite, magnesium stearate and the like.
These inorganic fine particles are preferably subjected to a surface treatment with a silane coupling agent, a titanium coupling agent, a higher fatty acid, silicone oil or the like in order to improve the dispersibility of the toner particles on the surface and the environmental stability. .
Examples of the cleaning aid include polystyrene fine particles and polymethyl methacrylate fine particles.
Various external additives may be used in combination.
The total amount of these external additives is preferably 0.1 to 20% by mass in the toner.

(Developer)
The toner according to the present invention can be used as a magnetic or non-magnetic one-component developer, but may be mixed with a carrier and used as a two-component developer. In the case where the toner according to the present invention is used as a two-component developer, the carrier may be a conventionally known material such as a metal such as iron, ferrite, or magnetite, or an alloy of such a metal with a metal such as aluminum or lead. Magnetic particles can be used, and ferrite particles are particularly preferable. Further, as the carrier, a coated carrier in which the surface of magnetic particles is coated with a coating agent such as a resin, a dispersion type carrier in which a magnetic fine powder is dispersed in a binder resin, or the like may be used.
The volume-based median diameter of the carrier is preferably 15 to 100 μm, more preferably 20 to 80 μm. The volume-based median diameter of the carrier can be typically measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by SYMPATEC) equipped with a wet disperser.

  Preferred carriers include a resin-coated carrier in which the surface of magnetic particles is coated with a resin, and a so-called resin-dispersed carrier in which magnetic particles are dispersed in a resin. The resin constituting the resin-coated carrier is not particularly limited, and examples thereof include olefin resins, styrene resins, styrene / acrylic resins, silicone resins, ester resins, and fluorine-containing polymer resins. Moreover, it does not specifically limit as resin which comprises a resin dispersion type carrier, A well-known thing can be used, For example, a styrene acrylic resin, a polyester resin, a fluorine resin, a phenol resin etc. can be used.

(Image forming method)
The above toner can be used in a general electrophotographic image forming method.

  According to such a method for producing a toner, basically, by containing a specific styrene-diene copolymer, low-temperature fixability can be obtained while blocking resistance is obtained. It is possible to produce a toner that can effectively exhibit the elasticity due to the copolymer and obtain excellent high-temperature offset resistance and crease fixability.

The reason why the elasticity by the specific styrene-diene copolymer is effectively exhibited in the obtained toner is presumed as follows.
That is, according to the manufacturing method of the present invention, the glass transition point (Tg) of the main resin and the sub resin is set to a specific range, respectively, and the main resin fine particles by the main resin and the sub resin fine particles by the sub resin The toner particles in a state in which the styrene-diene copolymer forms a domain of a specific size in the main resin by agglomerating the volume-based median diameters in a specific range. It is assumed that it will be obtained. The domain of the styrene-diene copolymer that is a rubber component is finely dispersed in a specific size, so that the contact area with the main resin that is a matrix becomes large. As a result, the specific styrene-diene system It is considered that the elasticity by the copolymer is effectively exhibited.

  According to such a toner manufacturing method, aggregation is performed in a state of high dispersion stability by the action of the electric charge of the second resin fine particles made of the second resin by the specific styrene-diene copolymer. Therefore, since the toner particles grow up to a predetermined diameter while the second resin fine particles are taken into the first resin, the generation of the reaction residue does not affect the production stability, that is, the first resin and Instead of the second resin, it can be suppressed to the same level as in the case of producing toner particles using only the first resin.

  As mentioned above, although embodiment of this invention was described concretely, embodiment of this invention is not limited to said example, A various change can be added.

  Hereinafter, specific examples of the present invention will be described, but the present invention is not limited thereto.

[Preparation example A of main resin fine particle dispersion]
Add 8 parts by weight of sodium dodecyl sulfate and 3000 parts by weight of ion-exchanged water to a reaction vessel equipped with a stirrer, temperature sensor, condenser, and nitrogen introduction device, and maintain the internal temperature while stirring at a stirring speed of 230 rpm under a nitrogen stream. The temperature was raised to 80 ° C. After the temperature increase, a polymerization initiator solution prepared by dissolving 10 parts by mass of potassium persulfate in 200 parts by mass of ion-exchanged water was added, and the liquid temperature was adjusted to 80 ° C.
Then
Styrene 480 parts by weight n-butyl acrylate 250 parts by weight Methacrylic acid 68 parts by weight n-octyl-3-mercaptopropionate 16 parts by weight of a polymerizable monomer mixture was dropped into the reaction vessel over 1 hour, then 80 Polymerization was carried out by heating and stirring at ° C. for 2 hours to prepare a dispersion of resin fine particles (1H).

A solution prepared by dissolving 7 parts by mass of polyoxyethylene (2) sodium dodecyl ether sulfate in 800 parts by mass of ion-exchanged water was added to a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introducing device. After heating the reaction vessel to 98 ° C., 260 parts by mass of the dispersion of the resin fine particles (1H),
Styrene 245 parts by mass n-butyl acrylate 120 parts by mass n-octyl-3-mercaptopropionate 1.5 parts by mass Polyethylene wax (melting point 81 ° C.) A polymerizable monomer mixture consisting of 190 parts by mass was added as it was, A dispersion containing emulsion particles (oil droplets) was prepared by mixing and dispersing for 1 hour using a mechanical disperser “CLEAMIX” (manufactured by M Technique Co., Ltd.) having a circulation path.
Next, a polymerization initiator solution prepared by dissolving 6 parts by mass of potassium persulfate in 200 parts by mass of ion-exchanged water is added to this dispersion, and polymerization is performed by heating and stirring at 82 ° C. for 1 hour. A dispersion of fine particles (1HM) was prepared.

Furthermore, a polymerization initiator solution prepared by dissolving 11 parts by mass of potassium persulfate in 400 parts by mass of ion-exchanged water was added, and styrene 435 parts by mass n-butyl acrylate 130 parts by mass methacrylic acid 33 parts by mass at a temperature of 82 ° C. A polymerizable monomer solution consisting of 8 parts by mass of n-octyl-3-mercaptopropionate was added dropwise over 1 hour. After completion of the dropwise addition, polymerization was performed by heating and stirring for 2 hours, and then cooled to 28 ° C. to obtain a dispersion of main resin fine particles [A].
About the dispersion of the obtained main resin fine particles [A], when the volume transition median diameter of the main resin fine particles [A] and the glass transition point (Tg) of the main resin fine particles [A] were measured by the following method, The glass transition point (Tg) was 37 ° C., and the volume-based median diameter was 132 nm.

(1) Glass transition point (Tg)
Measurement was performed as described above using a lyophilized dispersion of the main resin fine particles [A] as a measurement sample (main resin fine particles).

(2) Volume-based median diameter (D ₅₀ )
Measurement was performed as described above using a dispersion of main resin fine particles [A] as a measurement sample.

[Preparation Example B1 of Sub Resin Fine Particle Dispersion]
A pressure vessel is charged with 80 parts by mass of butadiene as a polymerizable monomer, 18 parts by mass of styrene, and 2 parts by mass of acrylic acid, and further 150 parts by mass of ion-exchanged water, 0.3 parts by mass of 1,1-diphenylethylene, t- To prepare 1 part by weight of dodecyl mercaptan, 0.2 part by weight of sodium dodecylbenzenesulfonate, and 1 part by weight of potassium persulfate, polymerization was performed at a temperature of 70 ° C. for 2 hours in a nitrogen atmosphere, and then the polymerization was completed. Further, the reaction was continued for 3 hours to complete the polymerization, whereby latex [LxB1] in which the sub-resin fine particles [B1] were dispersed was prepared.
For the obtained latex [LxB1], the glass transition point (Tg) of the sub-resin fine particles [B1], the volume-based median diameter (D ₅₀ ) of the sub-resin fine particles [B1], and the toluene-insoluble content of the sub-resin fine particles [B1] Was measured by the following method. The results are shown in Table 1.

(1) Glass transition point (Tg)
The measurement sample was changed to a freeze-dried sub-resin fine particle [B1] dispersion, and the measurement was performed in the same manner except that the measurement temperature was changed from 0 to 200 ° C to -120 to 100 ° C.

(2) Volume-based median diameter (D ₅₀ )
Measurement was performed as described above using a dispersion of main resin fine particles [A] as a measurement sample.

(3) Toluene-insoluble matter After adjusting the pH of the latex [LxB1] to 7.5, this copolymer latex is added to isopropanol under stirring to coagulate, and the coagulated product is washed and dried. A fixed amount (about 0.03 g) of the sample was immersed in a predetermined amount (about 100 mL) of toluene for 20 hours, and then filtered through a 120-mesh wire mesh, and the mass% of the obtained residual solid content with respect to the sample was calculated.

[Preparation Examples B2 to B10 of Sub Resin Fine Particle Dispersion]
In Preparation Example 1 of the dispersion of sub-resin fine particles, the type and / or addition amount of the polymerizable monomer to be added and / or the addition amount of sodium dodecylbenzenesulfonate were changed in accordance with the prescription in Table 1 below. Similarly, latexes [LxB2] to [LxB10] in which the sub-resin fine particles [B2] to [B10] were dispersed were prepared in the same manner.
For the obtained latex [LxB2] to [LxB10], the glass transition point (Tg), the volume-based median diameter of the sub resin fine particles [B2] to [B10], and the sub resin fine particles [B2] to [B10], respectively. Toluene insolubles were measured by the method described above. The results are shown in Table 1.
The sub resin fine particles [B1] to [B6] are according to the present invention, and the sub resin fine particles [B7] to [B10] are for comparison.

[Preparation Example of Colorant Fine Particle Dispersion]
While stirring a solution obtained by adding 90 parts by mass of sodium dodecyl sulfate to 1600 parts by mass of ion-exchanged water, 420 parts by mass of carbon black “Regal 330R” (manufactured by Cabot Corp.) is gradually added, and then a stirrer “Clearmix” A colorant fine particle dispersion [1] was prepared by performing a dispersion treatment using (M Technique Co., Ltd.).
The particle diameter of the colorant fine particles in this colorant fine particle dispersion [1] was measured using an electrophoretic light scattering photometer “ELS-800 (manufactured by Otsuka Electronics Co., Ltd.)” and found to be 110 nm.

<Example 1>
[Toner Production Example 1]
In a reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introducing device, 278 parts by mass (in terms of solid content) of the dispersion of the main resin fine particles [A] and 1400 parts by mass of ion-exchanged water are added and 5 mol / liter. After adjusting the pH to 10 by adding 12 parts by weight of latex [LxB1] in which the sub-resin fine particles [B1] are dispersed (in terms of solid content), polyoxyethylene (2 ) Add 123 parts by mass of an aqueous solution in which 3 parts by mass of sodium dodecyl ether sulfate was added to 120 parts by mass of ion-exchanged water, and then add 120 parts by mass of the colorant fine particle dispersion [1], and again 5 mol / liter of hydroxide. After adding sodium aqueous solution and adjusting pH to 10, liquid temperature was adjusted to 30 degreeC.
Next, an aqueous solution at 30 ° C. in which 35 parts by mass of magnesium chloride was dissolved in 35 parts by mass of ion-exchanged water as a flocculant was added to the stirred reaction system over 10 minutes. Then, after 3 minutes had elapsed after the addition, the temperature was started to rise, and the temperature of the reaction system was raised to 90 ° C. over 60 minutes to advance the aggregation. While measuring the size of the aggregated particles formed by aggregation with “Multisizer 3” (manufactured by Beckman Coulter), when the volume-based median diameter (D ₅₀ ) reaches 6.5 μm, 20% chloride After stopping the particle growth by adding 750 parts by mass of an aqueous sodium solution, stirring was continued at a liquid temperature of 98 ° C., and the average of aggregated particles was measured by a flow type particle image analyzer “FPIA-2100” (manufactured by Sysmex Corporation). While observing the circularity, fusion of the agglomerated fine particles was advanced, and after the average circularity reached 0.965, the liquid temperature was cooled to 30 ° C. to obtain an associated liquid [1].
This association liquid [1] was subjected to solid-liquid separation using a centrifugal dehydrator. Next, the solid material composed of toner particles was dried to a moisture content of 0.2% with a flash jet dryer, to obtain a toner base [1].
Toner [1] is obtained by subjecting 100 parts by mass of the toner base [1] to 0.8 parts by mass of fumed silica having a primary average particle diameter of 12 nm and mixing with an Henschel mixer. It was. The mixing conditions were 20 minutes with stirring force at a peripheral speed of 24 m / sec while maintaining the temperature in the range of 20-30 ° C. by water cooling.

[Toner Production Examples 2 to 10]
In the toner production example 1, the toner [2] to [10] using the associating liquids [2] to [10] is the same except that the addition amount of the main resin fine particles and the type and addition amount of the sub resin fine particles are changed according to Table 2. ] To [10] were obtained.
The toners [1] to [6] are those according to the present invention, and the toners [7] to [10] are for comparison.

[Evaluation 1: Evaluation of reaction residue ratio]
Pass each of the associating liquids [1] to [10] through a sieve having an opening of 150 μm, and after passing the sieve lightly washed with water, leave it at room temperature for 12 hours to dry, and determine the amount of reaction residue adhering to the sieve. It measured according to following formula (1), and calculated the ratio of the residual reaction residue according to following formula (2). The results are shown in Table 2.
Formula (1): Amount of reaction residue (g) = (mass of sieve after drying) − (mass of sieve at the time of drying measured in advance)
Formula (2): Ratio of reaction residue (%) = {Amount of reaction residue (g) / Mass of solid content in associated liquid (g)} × 100
In addition, when the ratio of the reaction residue is less than 1%, it is judged that productivity and manufacturing stability capable of mass production can be obtained.

[Evaluation 2: Evaluation of toner production stability]
According to each toner production example 1 to 11, the time required from when the aggregation liquid (magnesium chloride) was added to the time when the average circularity reached 0.965 after the preparation of the association liquid with the same formulation was repeated 10 times. Was measured in minutes, and the standard deviation of the required time was calculated. The results are shown in Table 2.
When the standard deviation is 30 or less, it is determined that high manufacturing stability can be obtained.

[Evaluation 3: Evaluation of occurrence of image defects]
For toners [1] to [10], a test image in which a solid black image was formed using an A3 size image support by mounting a toner on a commercially available copier “bizhub 751” (manufactured by Konica Minolta Business Technologies) The number of transfer defects in this test image, specifically, the number of white spot image defects of 0.1 mm or more was counted and evaluated according to the following evaluation criteria. The results are shown in Table 2.
In addition, when it is rank 3 or higher, it is determined that there is no practical problem.
-Evaluation criteria-
Rank 5: No image defect Rank 4: 1-2 image defects across A3 Rank 3: 3-5 image defects across A3 Rank 2: 6-20 image defects across A3 Rank 1: 21 or more image defects across A3

Claims (4)

A first resin having a glass transition point (Tg) of 33 ° C. to 58 ° C., a second resin comprising a styrene-diene copolymer having a glass transition point (Tg) of −70 ° C. to + 30 ° C., and a colorant A method for producing an electrostatic image developing toner comprising toner particles containing
A dispersion liquid (A) in which first resin fine particles having a volume-based median diameter of 75 to 300 nm are dispersed in an aqueous medium;
A dispersion liquid (B) in which second resin fine particles having a volume-based median diameter of 75 to 250 nm are dispersed in an aqueous medium,
After mixing the dispersion liquid (C) in which the fine particles of the colorant are dispersed in an aqueous medium, the toner particles are formed by aggregating the first resin fine particles, the second resin fine particles, and the colorant fine particles. A method for producing a toner for developing an electrostatic charge image, comprising a step of forming the toner.   2. The electrostatic image developing toner according to claim 1, wherein the content of the second resin is 2 to 15% by mass of the total of the first resin and the second resin. Method.   The electrostatic charge image development according to claim 1 or 2, wherein the second resin constituting the second resin fine particles in the dispersion (B) is a carboxy-modified styrene-diene copolymer. Of manufacturing toner. 4. The electrostatic image developing toner according to claim 1, wherein the styrene-diene copolymer constituting the second resin is a styrene-butadiene copolymer. 5. Production method.