JP5877060B2 - 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 and an electrostatic charge image developing toner obtained thereby.

In the field of electrophotography, with the development of an electrophotographic system, development of toner for electrophotography corresponding to higher image quality and higher speed is required.
In recent years, as a method of manufacturing a toner with particle size control, particle size reduction, and structure control corresponding to high image quality and low temperature fixing, fine resin particles are aggregated and fused in an aqueous medium. Aggregation and coalescence methods (emulsion aggregation method and aggregation fusion method) for obtaining toner are performed.

For example, in Patent Document 1, for the purpose of improving low-temperature fixability, chargeability, and storage stability, a colorant, resin particles containing crystalline polyester, and release agent particles are aggregated to obtain core aggregated particles. Resin particles containing amorphous polyester are adhered thereto to obtain core-shell aggregated particles, which are further held in an aqueous medium at a specific temperature, particularly at a temperature lower than the melting point of the crystalline polyester by 5 ° C. or more. A method for producing an electrophotographic toner including the step of obtaining is disclosed.
Patent Document 2 includes agglomeration of non-crystalline polyester, crystalline polyester, and colorant for the purpose of producing a toner excellent in fixing range, print quality, gloss, charging, etc., and further melting of crystalline polyester. A toner manufacturing method is disclosed that includes coalescence at a temperature below the starting point temperature.
Patent Document 3 discloses an amorphous resin, an infrared absorber having a maximum absorbance at a wavelength of about 850 nm to about 1100 nm, a crystalline resin, and an optional coloring for the purpose of improving printing gloss. A toner comprising an agent and an optional wax is disclosed.
Patent Document 4 discloses an amorphous polester resin having an alkenyl group, and the number of alkenyl groups having a branched structure among the alkenyl groups is 5% or more for the purpose of suppressing reduction in chargeability of the toner. And a toner for developing an electrostatic image comprising a binder resin containing a crystalline polyester resin having a specific ester group concentration.

JP 2011-186053 A JP 2008-250320 A JP 2011-81374 A JP 2011-81355 A

By including crystalline polyester or a release agent in the toner, the fixing temperature of the resulting toner can be lowered due to these melting characteristics. Thereby, the power consumption of the printing machine can be reduced, and a toner suitable for high-speed printing can be obtained. However, if a crystalline polyester or a release agent having a low melting point is used to lower the fixing temperature, there is a problem that the storage stability (heat resistant storage stability) of the toner decreases.
On the other hand, the toner obtained by the aggregation coalescence method (emulsion aggregation method) is suitable for encapsulating the crystalline polyester and the release agent, but is used as a colorant compared to the conventionally known melt-kneading method. It is difficult to disperse the obtained pigment or the like in the resin, it is difficult to improve the color developability, and there is a problem that the image density of the obtained printed matter is lowered.
An object of the present invention is to provide a toner for developing an electrostatic charge image that is excellent in image density and can achieve both low-temperature fixability and heat-resistant storage stability and a method for producing the same.

  The present inventors have considered that the factors affecting the image density, low-temperature fixability and heat-resistant storage stability are the relationship between the type of resin and the colorant, particularly the presence of the colorant in the resin. As a result, resin particles made of crystalline polyester, resin particles made of colorant and amorphous polyester, and release agent particles are aggregated, and resin particles containing amorphous polyester are added and kept at a specific temperature. Thus, it has been found that by forming a core-shell structure, it is possible to obtain a toner for developing an electrostatic image that is excellent in image density and can achieve both low-temperature fixability and heat-resistant storage stability.

That is, the present invention provides the following [1] and [2].
[1] A method for producing a core-shell type electrostatic image developing toner comprising the following steps (1) to (3):
Step (1): Resin particles (A) made of crystalline polyester (a), resin particles (B) containing a colorant and amorphous polyester (b), and release agent particles containing a release agent Step of aggregating to obtain aggregated particles (1) Step (2): Step of adding resin particles (C) containing amorphous polyester (c) to obtain aggregated particles (2) Step (3): The agglomerated particles (2) are at a temperature not less than 10 ° C. lower than the glass transition point of the amorphous polyester (b) and not less than 10 ° C. lower than the glass transition point of the amorphous polyester (c). A step of obtaining fused core-shell particles by maintaining the temperature below the melting point of the crystalline polyester (a) [2] A toner for developing an electrostatic image obtained by the production method according to [1].

  According to the present invention, it is possible to provide a toner for developing an electrostatic charge image that is excellent in image density and has both low-temperature fixability and heat-resistant storage stability, and a method for producing the same.

The method for producing an electrostatic charge image developing toner of the present invention includes the following steps (1) to (3).
Step (1): Resin particles (A) made of crystalline polyester (a), resin particles (B) containing a colorant and amorphous polyester (b), and release agent particles containing a release agent Step of aggregating to obtain aggregated particles (1) Step (2): Step of adding resin particles (C) containing amorphous polyester (c) to obtain aggregated particles (2) Step (3): The agglomerated particles (2) are at a temperature not less than 10 ° C. lower than the glass transition point of the amorphous polyester (b) and not less than 10 ° C. lower than the glass transition point of the amorphous polyester (c). A step of obtaining fused core-shell particles by maintaining the temperature below the melting point of the crystalline polyester (a).

The reason why the toner for developing an electrostatic image obtained by the production method of the present invention is excellent in image density and can achieve both low-temperature fixability and heat-resistant storage stability is not clear, but is considered as follows.
In the step (1) in the method of the present invention, the component which becomes the core of the obtained toner is aggregated. Here, resin particles (B) made of a colorant and amorphous polyester (b) are used. Since amorphous polyester does not have crystallinity, it has a high viscosity even when melted. For this reason, the dispersibility of the colorant can be increased when the resin particles (B) are obtained by mixing with the colorant, and the high dispersibility of the colorant can be maintained even in the fusing step when obtaining the toner. Is considered possible. Due to the high dispersibility of the colorant in the toner, the image density of the obtained toner is considered to increase. Moreover, the resin particle (A) which consists of crystalline polyester (a), and the mold release agent particle containing a mold release agent are further used for the component used as a core. These are particles having crystallinity. These are considered to be able to improve the fixing property of the toner at a low temperature because the viscosity rapidly decreases in the vicinity of the melting point.
In step (2), resin particles (C) containing amorphous polyester (c) are further added as a shell portion, and in step (3), they are fused to obtain core-shell particles. Here, by maintaining the temperature at a temperature of 10 ° C. lower than the glass transition point of the amorphous polyesters (b) and (c) and below the melting point of the crystalline polyester (a), the crystalline polyester becomes particles. While maintaining the crystalline state of the shape, the molecular mobility of the amorphous polyester is improved and fused. For this reason, it is considered that the obtained toner becomes particles in which the crystalline polyester is present in the amorphous polyester in a state having the crystalline domain, has high heat storage stability and is excellent in low-temperature fixability.
Hereinafter, each component and process used in the present invention will be described.

[Resin particles (A)]
In the present invention, the resin particles (A) are made of crystalline polyester (a).

(Crystalline polyester (a))
The crystalline polyester (a) of the present invention is a polyester having crystallinity.
Here, the “crystallinity” in the present invention is the ratio between the softening point and the maximum peak temperature of endotherm measured by a differential scanning calorimeter (DSC), (softening point (° C.)) / (Maximum endothermic peak temperature (° C.)). The crystallinity index is defined as 0.6 to 1.4, and the crystallinity index is preferably 0.8 to 1.3 from the viewpoint of low-temperature fixability of the toner. -1.2 are more preferable, and 0.9-1.1 are even more preferable.
The crystalline polyester (a) is obtained by condensation polymerization of an alcohol component and an acid component. Among them, from the viewpoint of promoting the crystallinity of the polyester and improving the low-temperature fixability of the toner, an α, ω-alkanediol having 2 to 12 carbon atoms and an aliphatic dicarboxylic acid having 4 to 12 carbon atoms, which is an acid component, It is preferable to obtain a crystalline polyester obtained by condensation polymerization of an α, ω-alkanediol having 4 to 12 carbon atoms and an aliphatic dicarboxylic acid having 8 to 12 carbon atoms. A crystalline polyester obtained by condensation polymerization of an α, ω-alkanediol having 6 to 12 carbon atoms and an aliphatic dicarboxylic acid having 8 to 12 carbon atoms is more preferable.
In the present invention, the acid component carboxylic acid which is a raw material monomer of the crystalline polyester (a) includes an acid anhydride and an alkyl ester having 1 to 3 carbon atoms.

The α, ω-alkanediol having 2 to 12 carbon atoms is preferably one having 6 to 12 carbon atoms from the viewpoint of promoting the crystallinity of the polyester and improving the low-temperature fixability of the toner.
Specific examples of the α, ω-alkanediol having 2 to 12 carbon atoms include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, etc. From the viewpoint of achieving both fixing properties and heat-resistant storage stability, 1,9-nonanediol and 1,10-decanediol are preferred.
A C2-C12 alpha, omega-alkanediol can be used individually or in combination of 2 or more types.

The aliphatic dicarboxylic acid having 4 to 12 carbon atoms is preferably one having 8 to 12 carbon atoms from the viewpoint of promoting the crystallinity of the polyester and improving the low-temperature fixability of the toner.
Examples of aliphatic dicarboxylic acids having 4 to 12 carbon atoms include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid, sebacic acid, 1,12-dodecanedioic acid, azelaic acid, etc. Among them, from the viewpoint of achieving both low-temperature fixability and heat-resistant storage stability of the toner, sebacic acid and 1,12-dodecanedioic acid are preferable, and sebacic acid is more preferable.
These can be used alone or in combination of two or more.
You may contain alcohol components other than the said C2-C12 alpha, omega-alkanediol, and acid components other than C4-C12 aliphatic dicarboxylic acid.

  The crystalline polyester (a) preferably has an acid group at the molecular end from the viewpoint of emulsifiability. Examples of the acid group include a carboxyl group, a sulfonic acid group, a phosphonic acid group, and a sulfinic acid group. Among these, a carboxyl group is preferable from the viewpoint of coexistence of the dispersibility of the resin, the cohesiveness of the resin particles, and the heat-resistant storage stability of the obtained toner.

The melting point of the crystalline polyester (a) is preferably 45 to 120 ° C, more preferably 60 to 90 ° C, and still more preferably 70 to 80 ° C, from the viewpoint of achieving both low-temperature fixability and heat-resistant storage stability of the toner. Among these, 70 to 75 ° C. is preferable from the viewpoint of low-temperature fixability, and 75 to 80 ° C. is preferable from the viewpoint of heat resistant storage stability.
From the same viewpoint, the softening point of the crystalline polyester (a) is preferably 50 to 150 ° C, more preferably 70 to 100 ° C, and still more preferably 75 to 90 ° C. Of these, 75 to 80 ° C. is preferable from the viewpoint of low-temperature fixability, and 80 to 90 ° C. is preferable from the viewpoint of heat-resistant storage stability.
The acid value of the crystalline polyester (a) is preferably 5 to 30 mgKOH / g, more preferably 10 to 27 mgKOH / g, and still more preferably 10 to 25 mgKOH / g, from the viewpoint of the charge amount of the toner.
In addition, crystalline polyester (a) can be used individually or in combination of 2 or more types.
In this invention, melting | fusing point and softening point of crystalline polyester (a) are calculated | required by the method as described in an Example. When two or more kinds are used in combination, the melting point of the crystalline polyester (a) having the largest weight ratio in the crystalline polyester (a) contained in the obtained toner is the melting point of the crystalline polyester (a) in the present invention. The melting point. When all have the same ratio, the lowest value is set. A softening point is calculated | required by the method as described in an Example as a mixture of crystalline polyester (a).

The crystalline polyester (a) can be produced by subjecting the alcohol component and the acid component to a polycondensation reaction, preferably in the presence of a catalyst, preferably at 180 to 250 ° C.
As the catalyst, from the viewpoint of the efficiency of the condensation polymerization reaction, a tin compound, a titanium compound, and the like are preferable, a tin compound is more preferable, and di (2-ethylhexanoic acid) tin, dibutyltin oxide, and the like can be given. Examples of the titanium compound include titanium diisopropylate bistriethanolamate.
Although there is no restriction | limiting in the usage-amount of a catalyst, 0.01-1 weight part is preferable with respect to 100 weight part of total amounts of an alcohol component and an acid component, and 0.1-0.7 weight part is more preferable.

  The polycondensation reaction is preferably carried out by placing an alcohol component and an acid component in a reaction vessel and maintaining at 140 to 200 ° C. for 5 to 15 hours, and then adding a catalyst and maintaining at 140 to 200 ° C. for 1 to 5 hours. Then, the reaction is allowed to proceed, and the method of obtaining the crystalline polyester by reducing the pressure to 5.0 to 20 kPa and maintaining it for 1 to 10 hours is preferable.

(Production of resin particles (A))
The resin particles (A) are preferably produced by a method in which the crystalline polyester (a) is dispersed in an aqueous medium and obtained as a dispersion containing the resin particles (A).
Examples of a method for obtaining a dispersion include a method in which polyester is added to an aqueous medium and subjected to a dispersion treatment with a disperser, and a method in which an aqueous medium is gradually added to polyester to perform phase inversion emulsification. From the viewpoint of low-temperature fixability, a method using phase inversion emulsification is preferred. Hereinafter, a method by phase inversion emulsification will be described.

First, the crystalline polyester (a) and the alkaline aqueous solution are melted and mixed to obtain a resin mixture.
In mixing, it is preferable to add a surfactant from the viewpoint of the emulsion stability of the resin.
Examples of the alkali in the alkaline aqueous solution include hydroxides of alkali metals such as potassium hydroxide and sodium hydroxide, and ammonia. From the viewpoint of improving the dispersibility of the resin, potassium hydroxide and sodium hydroxide are preferable. . Moreover, 1-20 weight% is preferable, as for the density | concentration of the alkali in alkaline aqueous solution, 1-15 weight% is more preferable, and 1.5-10 weight% is still more preferable.

Examples of the surfactant include nonionic surfactants, anionic surfactants, cationic surfactants, etc. Among them, nonionic surfactants are preferable, and nonionic surfactants and anionic surfactants or It is more preferable to use a cationic surfactant in combination, and it is more preferable to use a nonionic surfactant and an anionic surfactant in combination from the viewpoint of sufficiently emulsifying the resin.
When a nonionic surfactant and an anionic surfactant are used in combination, the weight ratio of the nonionic surfactant to the anionic surfactant (nonionic surfactant / anionic surfactant) is sufficient for the resin. From the viewpoint of emulsifying, it is preferably 0.3 to 10, more preferably 0.5 to 5.

Nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene fatty acid esters, oxyethylene / oxypropylene block copolymers, and the like. Among them, from the viewpoint of emulsion stability of the resin, polyoxyethylene alkyl ether Are preferred.
Examples of polyoxyethylene alkyl ethers include polyoxyethylene oleyl ether and polyoxyethylene lauryl ether.
Examples of polyoxyethylene fatty acid esters include polyethylene glycol monolaurate, polyethylene glycol monostearate, polyethylene glycol monooleate, and the like.

Examples of anionic surfactants include dodecyl benzene sulfonate, dodecyl sulfate, alkyl ether sulfate, and the like. From the viewpoint of improving the emulsion stability of the resin, dodecyl benzene sulfonate, alkyl ether sulfate. Is preferred.
As dodecylbenzenesulfonate, an alkali metal salt of dodecylbenzenesulfonate is preferable, and sodium dodecylbenzenesulfonate is more preferable. As dodecyl sulfate, an alkali metal salt of dodecyl sulfate is preferable, and sodium dodecyl sulfate is more preferable. As the alkyl ether sulfate, an alkali metal salt of alkyl ether sulfate is preferable, and sodium alkyl ether sulfate is more preferable.
The content of the surfactant is preferably 20 parts by weight or less, more preferably 15 parts by weight or less, still more preferably 0.1 to 10 parts by weight, with respect to 100 parts by weight of the resin constituting the resin particles (A). 0.5-10 weight part is still more preferable.

As a method for obtaining a resin mixture, a resin containing crystalline polyester (a), an aqueous alkali solution, and the above optional components, preferably a surfactant, are placed in a container, and the resin is melted uniformly while stirring with a stirrer. It is preferable to mix them.
The temperature at which the resin is melted and mixed is more preferably at least the melting point of the crystalline polyester (a) from the viewpoint of obtaining homogeneous resin particles.

Next, an aqueous medium is added to the resin mixture and phase inversion is performed to obtain a dispersion containing resin particles (A).
The aqueous medium preferably contains water as a main component, and from the viewpoint of environmental properties, the water content in the aqueous medium is preferably 80% by weight or more, more preferably 90% by weight or more, and further 95% by weight or more. Preferably, substantially 100% by weight is more preferable. As water, deionized water or distilled water is preferably used.
As components other than water, organic solvents that dissolve in water such as aliphatic alcohols having 1 to 5 carbon atoms; dialkyl (carbon numbers 1 to 3) ketones such as acetone and methyl ethyl ketone; and cyclic ethers such as tetrahydrofuran are used. Among these, from the viewpoint of preventing mixing into the toner, an aliphatic alcohol having 1 to 5 carbon atoms that does not dissolve the polyester is preferable, and methanol, ethanol, isopropanol, and butanol are more preferable.
The temperature at which the aqueous medium is added is more preferably equal to or higher than the melting point of the crystalline polyester (a) from the viewpoint of obtaining uniform resin particles.

  The addition rate of the aqueous medium is from 0.1 to 50 parts by weight / 100 parts by weight of the resin constituting the resin particles (A) until the phase inversion is completed from the viewpoint of making the resin particles have a small particle size. Preferably 0.1 to 30 parts by weight / minute, more preferably 0.5 to 10 parts by weight / minute, and 0.5 to 5 parts by weight / minute. Is more preferable. There is no restriction | limiting in the addition rate of the aqueous medium after phase inversion.

  The amount of the aqueous medium used is preferably 100 to 2000 parts by weight, and 150 to 1500 parts by weight with respect to 100 parts by weight of the resin constituting the resin particles (A) from the viewpoint of obtaining uniform aggregated particles in the subsequent aggregation step. More preferred is 150 to 500 parts by weight. From the viewpoint of the stability and ease of handling of the obtained resin particle dispersion, the solid content concentration is preferably 7 to 50% by weight, more preferably 10 to 40% by weight, still more preferably 20 to 40% by weight, More preferably, it is 25 to 35% by weight. In addition, solid content is the total amount of non-volatile components, such as resin and surfactant.

From the viewpoint of improving the heat resistant storage stability and fixability of the toner, it is preferable to crosslink the polyester resin contained in the resin particle (A), and the resin particle (A) is formed by crosslinking with a compound having an oxazoline group. More preferably.
As the compound having an oxazoline group, a compound containing a plurality of oxazoline groups in the molecule can be used, but a polymer containing an oxazoline group is preferred. The weight average molecular weight is preferably 500 to 2,000,000, more preferably 1,000 to 1,000,000 from the viewpoint of reactivity with the polyester resin.
Examples of commercially available polymers containing oxazoline groups include EPOCROSS WS series (water-soluble type, main chain acrylic), K series (emulsion type, main chain styrene / acrylic) manufactured by Nippon Shokubai Co., Ltd.
The content or addition amount of the compound having an oxazoline group is preferably 0.1 to 30 as a solid content with respect to 100 parts by weight of the resin in the resin dispersion, from the viewpoint of crosslinking reactivity with the resin and productivity. Parts by weight, more preferably 0.5 to 20 parts by weight, still more preferably 1 to 10 parts by weight.
By adding a compound having an oxazoline group and mixing at a predetermined temperature, a part of the resin particles dispersed in the resin dispersion is crosslinked. The temperature at this time is preferably 60 to 100 ° C, more preferably 70 to 98 ° C. The presence of crosslinking of the resin by the compound having an oxazoline group can be confirmed by an amide group generated by crosslinking.

The volume median particle size of the resin particles (A) in the dispersion containing the obtained resin particles (A) is preferably 0.02 to 2 μm. From the viewpoint of obtaining a toner capable of obtaining a high-quality image, 0.02 to 1.5 μm is preferable, 0.05 to 1 μm is more preferable, and 0.05 to 0.5 μm is still more preferable. Here, the volume-median particle size is a particle size at which the cumulative volume frequency calculated by the volume fraction is 50% calculated from the smaller particle size.
Further, the coefficient of variation (CV value) (%) of the particle size distribution of the resin particles is preferably 40% or less, more preferably 35% or less, and more preferably 30% from the viewpoint of obtaining a toner capable of obtaining a high-quality image. The following is more preferable, and 28% or less is more preferable. The CV value is a value represented by the following formula, and is specifically obtained by the method described in the examples.
CV value (%) = [standard deviation of particle size distribution (μm) / volume average particle size (μm)] × 100

[Resin particles (B)]
In the present invention, the resin particles (B) are composed of a colorant and an amorphous polyester (b). The resin particles (B) may contain other polyesters and the like as long as the effects of the present invention are not impaired. However, it is preferable that the resin particles (B) substantially consist of the colorant and the amorphous polyester (b).
The total content of the colorant and the amorphous polyester (b) in the resin particles (B) is preferably 99% by weight or more, more preferably 99.5% by weight or more, and further preferably 99.9%. % By weight or more.

[Amorphous polyester (b)]
The amorphous polyester (b) is an amorphous polyester.
“Amorphous” in the present invention means that the above-mentioned crystallinity index exceeds 1.4 or less than 0.6.
The amorphous polyester (b) preferably has a crystallinity index of less than 0.6 or more than 1.4 and 4 or less, more preferably from the viewpoint of image density and low-temperature fixability of the toner. It is less than 6, or 1.5 or more and 4 or less, More preferably, it is less than 0.6 or 1.5 or more and 3 or less, More preferably, it is less than 0.6 or 1.5 or more and 2 or less. The crystallinity index can be adjusted by the type and ratio of raw material monomers, production conditions (for example, reaction temperature, reaction time, cooling rate) and the like.

  As the amorphous polyester (b) contained in the resin particles (B), the same polyester as the amorphous polyester (c) described later can be preferably used. A resin made of the same monomer as the amorphous polyester (c) may be used, or a resin made of a different monomer may be used, but using a resin made of the same monomer is a viewpoint of aggregation control and low-temperature fixability of the toner. To preferred.

  The amorphous polyester (b) can be produced by a polycondensation reaction between an acid component and an alcohol component in the same manner as the crystalline polyester (a). Specific examples of the preferred acid component and alcohol component are the same as in the case of the amorphous polyester (c) described later.

The glass transition point, softening point, number average molecular weight and acid value of the amorphous polyester (b) are preferably in the same range as the amorphous polyester (c).
Among these, the glass transition point of the amorphous polyester (b) is preferably 50 to 70 ° C., more preferably 55 to 68 ° C., and 58 to 66 ° C. from the viewpoint of achieving both low temperature fixability and heat resistant storage stability of the toner. Is more preferable. In addition, the glass transition point of the amorphous polyester (b) is fused while maintaining the crystallinity of the crystalline polyester (a) from the viewpoint of achieving both low temperature fixability and heat resistant storage stability of the toner. More preferably, the temperature is lower than the melting point of the crystalline polyester (a).

  The amorphous polyester (b) may be used alone or in combination of two or more, and contains two types of polyesters having different softening points from the viewpoint of low-temperature fixability, offset resistance and durability of the toner. It is preferable to do. When two types of polyesters having different softening points are polyesters (b-1) and (b-2), respectively, the softening point of one polyester (b-1) is preferably 70 ° C. or higher and lower than 115 ° C., and the other polyester The softening point of (b-2) is preferably 115 ° C. or higher and 165 ° C. or lower. The weight ratio ((b-1) / (b-2)) between the polyester (b-1) and the polyester (b-2) is preferably 10/90 to 90/10, and 50/50 to 90/10. More preferred.

(Coloring agent)
The resin particles (B) are required to be colorant-containing resin particles containing a colorant from the viewpoint of sharpening the particle size distribution of the toner and improving the image density.
The content of the colorant in the resin particles (B) is preferably 1 to 20 parts by weight with respect to 100 parts by weight of the resin constituting the resin particles (B) from the viewpoint of the image density of the obtained printed matter. 10 parts by weight is more preferable, and 5 to 10 parts by weight is still more preferable.
The colorant may be contained in addition to the resin particles (B), but it is preferable that the colorant is substantially contained only in the resin particles (B) from the viewpoints of heat-resistant storage stability, chargeability and image density. The reason is considered as follows. The resin particles (B) containing the colorant are present on the core side (inner side) of the toner particles, and as a result, the surface of the toner particles is excellent in amorphous polyester (c) having excellent heat storage stability and chargeability. Therefore, the heat-resistant storage stability and chargeability of the toner are improved. Further, since the resin particles (B) contain the amorphous polyester (b), the colorant is well dispersed with the amorphous polyester (b), and the image density of the obtained printed matter is improved.

Examples of the colorant used in the present invention include pigments and dyes, and pigments are preferable from the viewpoint of improving the image density of the obtained printed matter.
Examples of the pigment include a cyan pigment, a yellow pigment, a magenta pigment, and a black pigment.
The cyan pigment is preferably a phthalocyanine pigment, and more preferably copper phthalocyanine. The yellow pigment is preferably a monoazo pigment, isoindoline pigment, or benzimidazolone pigment, and the magenta pigment is preferably a soluble azo pigment such as a quinacridone pigment or a BONA lake pigment, or an insoluble azo pigment such as a naphthol AS pigment. The black pigment is preferably carbon black.
Examples of the dye include an acridine dye, an azo dye, a benzoquinone dye, an azine dye, an anthraquinone dye, an indigo dye, a phthalocyanine dye, and an aniline black dye.
A coloring agent can be used individually by 1 type or in combination of 2 or more types.

(Production of resin particles (B))
The resin particles (B) can be obtained by the same method as the method for producing the resin particles (A) described above. The same alkaline aqueous solution, surfactant, and aqueous medium can be suitably used, and particularly preferred embodiments are specifically shown below.
As a method for obtaining the dispersion, from the viewpoint of low-temperature fixability of the obtained toner, a method by phase inversion emulsification is preferred as follows.
First, the amorphous polyester (b), the aqueous alkali solution, and the colorant are melted and mixed to obtain a resin mixture.
In mixing, it is preferable to add a surfactant from the viewpoint of the emulsion stability of the resin.
Specifically, a method in which the crystalline polyester (b), an aqueous alkali solution, and a colorant, preferably a surfactant, are placed in a container and the resin is melted and mixed uniformly while stirring with a stirrer is preferable.
The temperature at which the resin is melted and mixed is preferably equal to or higher than the glass transition point of the amorphous polyester (b).

The alkali in the alkaline aqueous solution is preferably potassium hydroxide or sodium hydroxide from the viewpoint of improving the dispersibility of the resin. Moreover, 1-30 weight% is preferable, as for the density | concentration of the alkali in aqueous alkali solution, 1-25 weight% is more preferable, and 1.5-20 weight% is still more preferable.
The kind of the surfactant is as described in the above-mentioned “Production of resin fine particles (A)”.
The content of the surfactant is preferably 20 parts by weight or less, more preferably 15 parts by weight or less, still more preferably 0.1 to 10 parts by weight, with respect to 100 parts by weight of the resin constituting the resin particles (B). 0.5-10 weight part is still more preferable.

Next, an aqueous medium is added to the resin mixture and phase inversion is performed to obtain a dispersion containing resin particles (B).
The type and content of the aqueous medium are as described in the above-mentioned “Production of resin fine particles (A)”.
The temperature at which the aqueous medium is added is preferably equal to or higher than the glass transition point of the amorphous polyester (b) from the viewpoint of obtaining homogeneous resin particles.
The addition rate of the aqueous medium is 0.1 to 50 parts by weight / 100 parts by weight of the resin constituting the resin particles (B) until the phase inversion is completed from the viewpoint of making the resin particles have a small particle size. Preferably 0.1 to 30 parts by weight / minute, more preferably 0.5 to 10 parts by weight / minute, and 0.5 to 5 parts by weight / minute. Is more preferable.
The amount of the aqueous medium used is preferably 100 to 2000 parts by weight, and 150 to 1500 parts by weight with respect to 100 parts by weight of the resin constituting the resin particles (B) from the viewpoint of obtaining uniform aggregated particles in the subsequent aggregation step. More preferred is 150 to 500 parts by weight. From the viewpoint of the stability and ease of handling of the obtained resin particle dispersion, the solid content concentration is preferably 7 to 50% by weight, more preferably 10 to 40% by weight, still more preferably 20 to 40% by weight, More preferably, it is 25 to 35% by weight.

The volume median particle size of the resin particles (B) in the dispersion containing the obtained resin particles (B) is preferably 0.02 to 2 μm. From the viewpoint of obtaining a toner capable of obtaining a high-quality image, 0.02 to 1.5 μm is preferable, 0.05 to 1 μm is more preferable, and 0.05 to 0.5 μm is still more preferable.
Further, the coefficient of variation (CV value) (%) of the particle size distribution of the resin particles is preferably 40% or less, more preferably 35% or less, and more preferably 30% from the viewpoint of obtaining a toner capable of obtaining a high-quality image. The following is more preferable, and 28% or less is more preferable.

[Releasing agent particles]
The release agent particles used in the present invention preferably contain a surfactant from the viewpoint of aggregation. In the case of using the surfactant, the content is preferably 0.01 to 10 parts by weight with respect to 100 parts by weight of the release agent from the viewpoint of aggregation and chargeability of the obtained toner, and preferably 0.1 to 5 parts by weight. Part by weight is more preferred.
The volume median particle size of the release agent particles is preferably from 0.1 to 1 μm, more preferably from 0.1 to 0.7 μm, and more preferably from 0.1 to 0. 5 μm is more preferable.
The CV value of the release agent particles is preferably 15 to 50%, more preferably 15 to 40%, and still more preferably 15 to 35%, from the viewpoint of the chargeability of the obtained toner.

As release agents, low molecular weight polyolefins such as polyethylene, polypropylene and polybutene; silicones having a softening point upon heating; fatty acid amides such as oleic acid amide and stearic acid amide; carnauba wax, rice wax and candelilla wax Plant waxes such as beeswax; animal waxes such as beeswax; mineral / petroleum waxes such as montan wax, paraffin wax, and Fischer-Tropsch wax.
The melting point of the release agent is preferably 60 to 100 ° C., more preferably 60 to 90 ° C., further preferably 70 to 90 ° C., and more preferably 73 to 85 ° C. from the viewpoint of low-temperature fixability and heat-resistant storage stability of the toner. Further preferred. These release agents can be used alone or in combination of two or more, and it is possible to use two or more release agents having a melting point of 60 to 90 ° C. to achieve low-temperature fixability and heat resistant storage of the toner. From the viewpoint of sex.
In the present invention, the melting point of the release agent is determined by the method described in the examples.
The use amount of the release agent is usually preferably 1 to 20 parts by weight, preferably 2 to 15 parts by weight with respect to 100 parts by weight of the resin in the toner, from the viewpoint of improving the releasability of the toner and improving the low-temperature fixability. Part is more preferred.
The release agent particles are preferably obtained as a dispersion of release agent particles by dispersing the release agent in an aqueous medium.
The dispersion of the release agent particles is preferably obtained by dispersing the release agent and the aqueous medium using a disperser in the presence of a surfactant at a temperature equal to or higher than the melting point of the release agent. As the disperser to be used, a homogenizer, an ultrasonic disperser or the like is preferable.
The aqueous medium used in this production is preferably used when obtaining a resin mixture, the surfactant is preferably an anionic surfactant, more preferably a hydrophilic group is a carboxy group, and a polycarboxylate is used. Preferably used.

[Resin particles (C)]
In the present invention, the resin particles (C) need to contain the amorphous polyester (c) from the viewpoint of achieving both low-temperature fixability and heat-resistant storage stability of the toner.
The glass transition point of the resin particle (C) is appropriately determined depending on the glass transition point of the resin such as the amorphous polyester (c) constituting the resin particle (C), the type and amount of the additive, etc. From the viewpoints of durability, low-temperature fixability, chargeability, scattering properties, and heat-resistant storage stability, it is preferably 45 ° C or higher, more preferably 45 to 70 ° C, still more preferably 50 to 70 ° C, and more preferably 55 to 65 ° C. Further preferred.

  The resin particles (C) preferably contain 70% by weight or more of amorphous polyester (c), more preferably 80% by weight or more, more preferably from the viewpoint of heat-resistant storage stability, scattering properties and chargeability of the toner. Contains 90% by weight or more, more preferably 95% by weight or more, and still more preferably 100% by weight.

(Amorphous polyester (c))
In the present invention, the amorphous polyester (b) is a polyester having a crystallinity index of more than 1.4 or less than 0.6.
The amorphous polyester (c) preferably has a crystallinity index of less than 0.6 or more than 1.4 and 4 or less, more preferably less than 0.6, from the viewpoint of low-temperature fixability of the toner. It is 1.5 or more and 4 or less, More preferably, it is less than 0.6 or 1.5 or more and 3 or less, More preferably, it is less than 0.6 or 1.5 or more and 2 or less. The crystallinity index can be adjusted by the type and ratio of raw material monomers, production conditions (for example, reaction temperature, reaction time, cooling rate) and the like.
As the amorphous polyester (c), an amorphous polyester (b) having an acid group at the molecular end is preferable. Examples of the acid group include a carboxyl group, a sulfonic acid group, a phosphonic acid group, and a sulfinic acid. Among these, a carboxyl group is preferable from the viewpoint of facilitating emulsification of the polyester.

  The amorphous polyester (c) can be produced by subjecting an acid component and an alcohol component to a polycondensation reaction in the same manner as the crystalline polyester (a).

Examples of the acid component include dicarboxylic acids, trivalent or higher polyvalent carboxylic acids, acid anhydrides thereof, and alkyl (C 1 -C 3) esters thereof, among which dicarboxylic acids are preferable.
Specific examples of the dicarboxylic acid include succinic acid, phthalic acid, isophthalic acid, terephthalic acid substituted with an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms such as dodecyl succinic acid, dodecenyl succinic acid, and octenyl succinic acid. Acid, sebacic acid, fumaric acid, maleic acid, adipic acid, azelaic acid, succinic acid, cyclohexanedicarboxylic acid and the like can be mentioned, among which fumaric acid, dodecenyl succinic acid and terephthalic acid are preferable, and dodecenyl succinic acid and terephthalic acid are more preferable.
Specific examples of the trivalent or higher polyvalent carboxylic acid include trimellitic acid, 2,5,7-naphthalenetricarboxylic acid, pyromellitic acid, and the like. Among these, from the viewpoint of offset resistance, trimellitic acid and its Acid anhydrides are preferred.
An acid component can be used individually or in combination of 2 or more types.
From the viewpoint of high temperature offset resistance of the toner, the amorphous polyester (c) is an acid containing a trivalent or higher polyvalent carboxylic acid and an acid anhydride or an alkyl ester thereof, preferably trimellitic acid or an anhydride thereof. It is preferable to use at least one amorphous polyester (c) obtained using the components.

As an alcohol component, the thing similar to the said alcohol component used for crystalline polyester (a) is mentioned. Among these, it is preferable to use an aromatic diol from the viewpoint of obtaining amorphous polyester, and polyoxypropylene-2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene-2,2-bis ( It is more preferable to use an alkylene (2 to 3 carbon) oxide adduct (average number of added moles of 1 to 16) of bisphenol A such as 4-hydroxyphenyl) propane.
An alcohol component can be used individually or in combination of 2 or more types.

The glass transition point of the amorphous polyester (c) is preferably 50 to 70 ° C., more preferably 55 to 68 ° C., and still more preferably 58 to 66 ° C., from the viewpoint of achieving both low temperature fixability and heat resistant storage stability of the toner. .
The softening point of the amorphous polyester (c) is preferably 70 to 165 ° C, more preferably 70 to 140 ° C, and still more preferably 90 to 140 ° C, from the viewpoint of achieving both low temperature fixability and heat resistant storage stability of the toner. 100-130 degreeC is especially preferable.
In addition, when using 2 or more types of amorphous polyesters (c), the glass transition point and the softening point are each described in the examples as a mixture of 2 or more types of amorphous polyesters (c). The value obtained by the method.

  The acid value of the amorphous polyester (c) is preferably 6 to 35 mgKOH / g, more preferably 10 to 35 mgKOH / g, and still more preferably 15 to 35 mgKOH / g, from the viewpoint of emulsification in the aqueous medium of the resin.

  The amorphous polyester (c) preferably contains two kinds of polyesters having different softening points from the viewpoint of achieving both low-temperature fixability and heat-resistant storage stability of the toner. When two types of polyesters having different softening points are polyesters (c-1) and (c-2), respectively, the softening point of one polyester (c-1) is preferably 70 ° C. or higher and lower than 115 ° C., and the other polyester The softening point of (c-2) is preferably 115 ° C. or higher and 165 ° C. or lower. The weight ratio ((c-1) / (c-2)) between the polyester (c-1) and the polyester (c-2) is preferably 10/90 to 90/10, and 50/50 to 90/10. More preferred.

(Production of resin particles (C))
The resin particles (C) can be obtained by a method similar to the method for producing the resin particles (A) described above. The same alkaline aqueous solution, surfactant, and aqueous medium can be suitably used, and particularly preferred embodiments are specifically shown below.
As a method for obtaining the dispersion, from the viewpoint of low-temperature fixability of the obtained toner, a method by phase inversion emulsification is preferred as follows.
First, optional components such as a resin containing an amorphous polyester (c), an aqueous alkali solution, and a colorant are melted and mixed to obtain a resin mixture.
Examples of the optional component include a colorant, a charge control agent, a reinforcing filler such as a fibrous substance, an antioxidant, an anti-aging agent, and the like, and they may be used as long as the effects of the present invention are not impaired. Among these, it is preferable to use a colorant from the viewpoint of improving the image density of the toner.
In mixing, it is preferable to add a surfactant from the viewpoint of the emulsion stability of the resin.
Specifically, a method in which optional components such as crystalline polyester (c), an alkaline aqueous solution, and a colorant, preferably a surfactant, are placed in a container, and the resin is melted and mixed uniformly while stirring with a stirrer. Is preferred.
The temperature at which the resin is melted and mixed is preferably equal to or higher than the glass transition point of the amorphous polyester (c).

The alkali in the alkaline aqueous solution is preferably potassium hydroxide or sodium hydroxide from the viewpoint of improving the dispersibility of the resin. Moreover, 1-30 weight% is preferable, as for the density | concentration of the alkali in aqueous alkali solution, 1-25 weight% is more preferable, and 1.5-20 weight% is still more preferable.
The type and content of the surfactant are as described in the above-mentioned “Production of resin fine particles (A)”.

Next, an aqueous medium is added to the resin mixture and phase inversion is performed to obtain a dispersion containing resin particles (C).
The type and content of the aqueous medium are as described in the above-mentioned “Production of resin fine particles (A)”.
The temperature at which the aqueous medium is added is preferably equal to or higher than the glass transition point of the amorphous polyester (c) from the viewpoint of obtaining homogeneous resin particles.
The addition rate, amount used, and solid concentration of the aqueous medium are as described in the above-mentioned “Production of resin fine particles (A)”.

The volume median particle size of the resin particles (C) in the dispersion containing the obtained resin particles (C) is preferably 0.02 to 2 μm. From the viewpoint of obtaining a toner capable of obtaining a high-quality image, 0.02 to 1.5 μm is preferable, 0.05 to 1 μm is more preferable, and 0.05 to 0.5 μm is still more preferable.
Further, the coefficient of variation (CV value) (%) of the particle size distribution of the resin particles is preferably 40% or less, more preferably 35% or less, and more preferably 30% from the viewpoint of obtaining a toner capable of obtaining a high-quality image. The following is more preferable, and 28% or less is more preferable.

[Method for producing toner for electrophotography]
The method for producing an electrophotographic toner of the present invention includes the following steps (1) to (3). Hereinafter, each step will be described.

[Step (1)]
In step (1), resin particles (A) made of crystalline polyester (a), resin particles (B) made of a colorant and amorphous polyester (b), and release agent particles containing a release agent are used. It is a step of agglomerating to obtain aggregated particles (1).

In this step, first, the resin particles (A), the resin particles (B), and the release agent particles are mixed in an aqueous medium to obtain a mixed dispersion.
There is no restriction | limiting in order of mixing, You may add any in order and may add simultaneously.
In the mixed dispersion, the resin particles (A) are preferably 1 to 10 parts by weight, and more preferably 1 to 5 parts by weight. The resin particles (B) are preferably 5 to 30 parts by weight, and more preferably 10 to 20 parts by weight. The aqueous medium is preferably 60 to 90 parts by weight, and more preferably 70 to 80 parts by weight. The release agent particles are preferably 1 to 20 parts by weight, and more preferably 2 to 10 parts by weight with respect to 100 parts by weight of the total of the resin and the colorant, from the viewpoint of toner releasability and low-temperature fixability.
The mixing temperature is preferably 0 to 40 ° C. from the viewpoint of aggregation control.

Next, the particles in the mixed dispersion are aggregated to obtain a dispersion of aggregated particles (1). It is preferable to add a flocculant for efficient aggregation.
As the aggregating agent, a quaternary salt cationic surfactant; an inorganic aggregating agent such as an inorganic metal salt, an inorganic ammonium salt, or a bivalent or higher-valent metal complex is preferably used.
Examples of the inorganic metal salt include metal salts such as sodium sulfate, sodium chloride, calcium chloride and calcium nitrate, and inorganic metal salt polymers such as polyaluminum chloride and polyaluminum hydroxide. Examples of the inorganic ammonium salt include ammonium sulfate, ammonium chloride, ammonium nitrate and the like, and ammonium sulfate is more preferable.
The use amount of the flocculant is preferably 50 parts by weight or less, more preferably 40 parts by weight or less, with respect to 100 parts by weight of the resin constituting the resin particles (A) and (B), from the viewpoint of toner charging properties. More preferably, it is 30 parts by weight or less. Further, from the viewpoint of the cohesiveness of the resin particles, it is preferably 1 part by weight or more, more preferably 3 parts by weight or more, and further preferably 5 parts by weight with respect to 100 parts by weight of the resin constituting the resin particles (A) and (B). It is more than part by weight. Considering the above points, the amount of monovalent salt used is preferably 1 to 50 parts by weight, more preferably 3 to 100 parts by weight of the resin constituting the resin particles (A) and (B). 40 parts by weight, more preferably 5 to 30 parts by weight.

  As an aggregating method, an aggregating agent is preferably added dropwise as an aqueous solution to a container containing a mixed dispersion. The flocculant may be added at one time, or may be added intermittently or continuously. However, it is preferable to perform sufficient stirring at the time of addition and after completion of the addition. From the viewpoint of controlling aggregation and shortening the toner production time, the dropping time of the aggregating agent is preferably 1 to 120 minutes. Moreover, 0-50 degreeC is preferable from a viewpoint of aggregation control.

  The volume-median particle size of the obtained aggregated particles (1) is preferably 1 to 10 μm, more preferably 2 to 9 μm, and still more preferably 3 from the viewpoints of reducing the particle size and improving the image quality and handling as particles. ~ 6 μm. The CV value is preferably 30% or less, more preferably 28% or less, and still more preferably 25% or less.

[Step (2)]
Step (2) is a step of obtaining aggregated particles (2) by adding resin particles (C) containing amorphous polyester (c) to aggregated particles (1) obtained in step (1). is there.
In this step, a dispersion of resin particles (C) containing amorphous polyester (c) is added to the dispersion of aggregated particles (1) obtained in step (1) to obtain aggregated particles (1 It is preferable that the resin particles (C) are further adhered to the particles to obtain aggregated particles (2).

Before adding the dispersion liquid (resin particle (C) dispersion liquid) containing the resin particles (C) to the dispersion liquid (aggregated particle (1) dispersion liquid) containing the aggregated particles (1), the aggregated particle (1) An aqueous medium may be added to the dispersion for dilution, and it is preferable to add an aqueous medium. By adding the aqueous medium, the resin particles (C) can be more uniformly attached to the aggregated particles (1).
When the resin particle (C) dispersion is added to the aggregated particle (1) dispersion, the aggregating agent may be used in order to efficiently attach the resin particle (C) to the aggregated particle (1).
As a preferable addition method in the case of adding the resin particle (C) dispersion to the aggregated particle (1) dispersion, a method of simultaneously adding the coagulant and the resin particle (C) dispersion, the coagulant and the resin particle (C ) A method of alternately adding the dispersion liquid, and a method of adding the resin particle (C) dispersion liquid while gradually raising the temperature of the aggregated particle (1) dispersion liquid. By doing in this way, the cohesiveness fall of the coagulated particle (1) and the resin particle (C) by the coagulant | flocculant density | concentration fall can be prevented. From the viewpoint of toner productivity and manufacturing simplicity, it is preferable to add the resin particle (C) dispersion while gradually raising the temperature of the aggregated particle (1) dispersion.

  The temperature in the system in this step is 5 ° C. or more lower than the melting point of the crystalline polyester (a) contained in the resin particles (A) from the viewpoint of low-temperature fixability and heat-resistant storage stability of the toner. ) Is preferably 3 ° C. or more lower than the glass transition point, and more preferably 5 ° C. or more. When the aggregated particles (2) are produced in this temperature range, the low-temperature fixability and heat-resistant storage stability of the obtained toner are improved. The reason for this is not clear, but because the agglomeration of the aggregated particles (2) does not occur, the generation of coarse particles is suppressed, and the crystallinity of the crystalline polyester (a) can be maintained. Conceivable.

  The addition amount of the resin particles (C) is the weight ratio of the resin particles (C) to the total amount of the resin particles (A) and (B) (resin particles (C ) / (Resin particles (A) + (B))) is preferably 0.3 to 1.5, more preferably 0.3 to 1.0, still more preferably 0.35 to 0.75. Is preferred.

  The resin particle (C) dispersion may be added continuously over a certain period of time, may be added at a time, or may be added in a plurality of divided portions. It is preferable to add them continuously or in several divided portions. By adding as described above, the resin particles (C) are likely to selectively adhere to the aggregated particles (1). Among these, it is preferable to add continuously over a certain time from the viewpoint of promoting selective adhesion and the efficiency of production. The time for continuous addition is preferably 1 to 10 hours, and more preferably 3 to 8 hours, from the viewpoint of obtaining uniform aggregated particles (2) and from the viewpoint of shortening the production time.

  The volume median particle size of the aggregated particles (2) obtained in the step (2) is preferably 1 to 10 μm, more preferably 2 to 10 μm, from the viewpoint of obtaining a toner capable of obtaining a high quality image. -9 μm is more preferable, and 4-6 μm is more preferable.

[Step (3)]
In step (3), the aggregated particles (2) are at a temperature of 10 ° C. lower than the glass transition point of the amorphous polyester (b) and 10 ° C. higher than the glass transition point of the amorphous polyester (c). This is a step of obtaining fused core-shell particles by maintaining the temperature at a low temperature or higher and lower than the melting point of the crystalline polyester (a).
In this step, the particles in the aggregated particles (2), which are mainly physically attached to each other, are fused and integrated to form core-shell particles.

From the viewpoint of fusing property and toner productivity, in this step, it is necessary to maintain the temperature at a temperature 10 ° C. lower than the glass transition point of the amorphous polyesters (b) and (c). It can be held at a temperature of 8 ° C. or higher, preferably 6 ° C. or lower, more preferably 5 ° C. or lower than the glass transition point of the amorphous polyesters (b) and (c). More preferably, from the viewpoint of improving heat-resistant storage stability, in this step, a temperature not higher than 10 ° C., preferably not higher than 8 ° C., more preferably not higher than the glass transition point of the amorphous polyester (b). Is more preferably maintained at a temperature not higher than 6 ° C.
Further, from the viewpoint of heat-resistant storage stability of the toner, it is necessary to keep the temperature below the melting point of the crystalline polyester (a) in this step. It is more preferable that the temperature is maintained at a temperature lower by 3 ° C., more preferably 5 ° C. or lower.
Further, from the viewpoint of low-temperature fixability of the toner, in this step, the toner is held at a temperature lower than the melting point of the release agent by 5 ° C. or more, preferably 7 ° C. or less, more preferably 10 ° C. or less. preferable.
In this step, from the viewpoint of particle fusibility, the temperature is preferably 55 to 70 ° C, more preferably 57 to 65 ° C, and still more preferably 58 to 64 ° C.

  The holding time in this step is preferably 1 to 24 hours, more preferably 1 to 18 hours, still more preferably 2 to 12 hours, and still more preferably 2 from the viewpoints of particle fusing property, heat resistant storage stability and toner productivity. ~ 5 hours.

In this step, it is preferable to confirm the progress of fusion by monitoring the circularity of the generated core-shell particles. When the circularity reaches 0.955 or more, the cooling is performed and the fusion is stopped. The roundness of the finally obtained core-shell particles is 0.955 to 0.995, preferably 0.958 to 0.985, more preferably 0.960 to 0.985, from the viewpoint of the cleaning properties of the obtained toner. Preferably, 0.965 to 0.980 is even more preferable.
The circularity monitoring can be suitably performed by the following method.
-Preparation of dispersion: A dispersion of core-shell particles is prepared by diluting with deionized water so that the solid content concentration of the core-shell particles is 0.001 to 0.05%. The toner dispersion was prepared by adding 50 mg of toner to 5 ml of 5% by weight polyoxyethylene lauryl ether (Emulgen 109P) aqueous solution, dispersing for 1 minute with an ultrasonic disperser, adding 20 ml of distilled water, Prepare by dispersing for 1 minute in a sonic disperser.
Measurement device: Flow-type particle image analyzer (manufactured by Sysmex Corporation, trade name: FPIA-3000)
・ Measurement mode: HPF measurement mode

From the viewpoint of improving the image quality of the toner, the volume-median particle size of the core-shell particles obtained in this step is preferably 2 to 10 μm, more preferably 2 to 8 μm, more preferably 2 to 7 μm, still more preferably 3 to 8 μm. More preferably, it is 4-6 micrometers.
The volume-median particle size of the fused core-shell particles obtained in this step is preferably not more than the volume-median particle size of the aggregated particles (2). That is, in this step, it is preferable that the core shell particles do not aggregate and fuse.

[Post-processing process]
In the present invention, a post-treatment step may be performed after step (3), and it is preferable to obtain toner particles by isolating the core-shell particles.
Since the core-shell particles obtained in the step (3) are present in the aqueous medium, it is preferable to first perform solid-liquid separation. For solid-liquid separation, a suction filtration method or the like is preferably used.
It is preferable to perform washing after the solid-liquid separation. The washing is preferably performed a plurality of times.
Next, although it is preferable to dry, the temperature at the time of drying is preferably set so that the temperature of the core-shell particle itself is 5 ° C. or more lower than the melting point of the crystalline polyester, and is set so as to be 10 ° C. or more lower. It is more preferable. As a drying method, it is preferable to use a vibration type fluidized drying method, a spray drying method, a freeze drying method, a flash jet method, or the like. The water content after drying is preferably adjusted to 1.5% by weight or less, more preferably 1.0% by weight or less, from the viewpoint of reducing the amount of toner scattered and charging properties.

[Toner for electrostatic image development]
(toner)
The toner particles obtained by drying or the like can be used as they are as the toner for developing an electrostatic image of the present invention, but the toner particle surface treated as described below is used as a toner for developing an electrostatic image. It is preferable.
The softening point of the obtained toner is preferably 60 to 140 ° C., more preferably 60 to 130 ° C., and still more preferably 60 to 120 ° C. from the viewpoint of low-temperature fixability of the toner. The glass transition point is preferably 30 to 80 ° C., more preferably 40 to 70 ° C. from the viewpoints of low-temperature fixability, durability, and storage stability.
The toner obtained by the method of the present invention has a core-shell structure, and amorphous polyester (c) is preferably contained in the shell part in an amount of 50 to 100% by weight, more preferably 70 to 100% by weight, still more preferably 90 to 90%. Contains 100% by weight.
The volume median particle size of the toner is preferably 1 to 10 μm, more preferably 2 to 8 μm, still more preferably 3 to 7 μm, and still more preferably 4 to 6 μm, from the viewpoint of high image quality and productivity of the toner.
The CV value of the toner is preferably 30% or less, more preferably 27% or less, still more preferably 25% or less, and further preferably 22% or less, from the viewpoint of high image quality and productivity.

(External additive)
In the toner for developing an electrostatic charge image of the present invention, the toner particles can be used as the toner as they are, but it is preferable to use a toner obtained by adding a fluidizing agent or the like to the toner particle surface as an external additive.
Examples of the external additive include inorganic fine particles such as hydrophobic silica, titanium oxide fine particles, alumina fine particles, and cerium oxide fine particles, and polymer fine particles such as polycarbonate, polymethyl methacrylate, and silicone resin. Among these, Hydrophobic silica is preferred.
When the surface treatment of the toner particles is performed using the external additive, the amount of the external additive added is preferably 1 to 6 parts by weight, more preferably 100 parts by weight of the toner particles before the treatment with the external additive. 2 to 5 parts by weight.

  The electrostatic image developing toner obtained by the present invention can be used as a one-component developer or mixed with a carrier and used as a two-component developer.

  Each property value of polyester, resin particles, toner, etc. was measured and evaluated by the following method.

[Acid value of polyester]
It measured according to JIS K0070. However, the measurement solvent was a mixed solvent of acetone and toluene (acetone: toluene = 1: 1 (volume ratio)).

[Polyester softening point, endothermic maximum peak temperature, melting point and glass transition point]
(1) Softening point Using a flow tester (manufactured by Shimadzu Corporation, trade name: CFT-500D), a load of 1.96 MPa was applied by a plunger while heating a 1 g sample at a heating rate of 6 ° C / min. And extruded from a nozzle with a diameter of 1 mm and a length of 1 mm. The amount of flow tester drop by the flow tester was plotted against the temperature, and the temperature at which half the sample flowed out was taken as the softening point.
(2) Endothermic maximum peak temperature, melting point and glass transition point Using a differential scanning calorimeter (manufactured by PerkinElmer, trade name: Pyris 6 DSC), the temperature is raised to 200 ° C., and the temperature lowering rate is 50 ° C./min. The sample cooled to 0 ° C. was measured at a heating rate of 10 ° C./min. Of the endothermic peaks observed, the peak temperature having the maximum peak area was defined as the maximum endothermic peak temperature. In the case of crystalline polyester, the peak temperature was taken as the melting point. In the case of amorphous polyester, the glass transition point was defined as the intersection temperature between the base line extension below the maximum peak temperature of endotherm and the tangent showing the maximum slope from the peak rising portion to the peak apex.

[Volume Median Particle Size (D ₅₀ ), Volume Average Particle Size (D _v ), and Particle Size Distribution of Resin Particles and Release Agent Particles]
(1) Measuring device: Laser diffraction particle size measuring machine (Horiba, Ltd., trade name: LA-920)
(2) Measurement conditions: Distilled water was added to the measurement cell, and the volume-median particle size (D ₅₀ ) was measured at a concentration at which the absorbance was in an appropriate range. Further, the CV value as a particle size distribution was calculated according to the following formula from the volume average particle size and standard deviation displayed by the particle size measuring instrument.
CV value (%) = (standard deviation of particle size distribution / volume average particle size) × 100

[Solid content concentration of resin particle dispersion and release agent particle dispersion]
Using an infrared moisture meter (trade name: FD-230, manufactured by Ketto Scientific Laboratory Co., Ltd.), a measurement sample 5 g was dried at a temperature of 150 ° C. and a measurement mode 96 (monitoring time 2.5 minutes / variation width 0.05%). ) To measure the moisture percentage. The solid content concentration was calculated according to the following formula.
Solid content concentration (% by weight) = 100-M
M: moisture (%) = [(W−W ₀ ) / W] × 100
W: Sample weight before measurement (initial sample weight)
W ₀ : Sample weight after measurement (absolute dry weight)

[Volume-Medium Particle Size of Toner (D ₅₀ )]
The volume median particle size of the toner was measured as follows.
Measuring instrument: Coulter Multisizer III (trade name, manufactured by Beckman Coulter)
・ Aperture diameter: 50μm
・ Analysis software: Multisizer III version 3.51 (trade name, manufactured by Beckman Coulter)
Electrolyte: Isoton II (trade name, manufactured by Beckman Coulter)
-Dispersion: Polyoxyethylene lauryl ether (manufactured by Kao Corporation, trade name: Emulgen 109P, HLB: 13.6) was dissolved in the electrolytic solution to obtain a dispersion having a concentration of 5% by weight.
-Dispersion condition: 10 mg of a toner measurement sample is added to 5 mL of the dispersion, and dispersed for 1 minute with an ultrasonic disperser, and then 25 mL of electrolyte is added, and further dispersed for 1 minute with an ultrasonic disperser. A sample dispersion was prepared.
Measurement conditions: After adjusting the particle size of 30,000 particles to a concentration that can be measured in 20 seconds by adding the sample dispersion to 100 mL of the electrolytic solution, 30,000 particles are measured, and the volume is medium. The particle size (D ₅₀ ) was determined.

[Evaluation of heat-resistant storage stability of toner]
20 g of toner was put in a wide-mouthed polybin having an internal volume of 100 ml, sealed, and allowed to stand at a temperature of 50 ° C. for 12 hours. Then, it is allowed to stand for 12 hours or more while being sealed at a temperature of 25 ° C. and cooled. A 250 μm mesh sieve is set on a vibrating table of a powder tester (manufactured by Hosokawa Micron Corporation). The toner (20 g) was placed thereon and vibrated for 30 seconds, and the weight of the toner remaining on the sieve was measured. The smaller the value, the more the toner is not blocked and the better heat resistant storage stability.

[Evaluation of low-temperature fixability (minimum fixing temperature) of toner]
Using a commercially available printer (trade name: MicroLine 5400, manufactured by Oki Data Co., Ltd.) on high-quality paper (Fuji Xerox Co., Ltd., J paper A4 size), the toner adhesion amount on the paper is 0.42 to 0.48 mg. A solid image of / cm ² was output without being fixed at a length of 50 mm, leaving a margin of 5 mm from the top edge of the A4 paper.
Next, the same printer with the temperature-variable fixing device prepared was prepared, the temperature of the fixing device was set to 90 ° C., and fixing was performed at a speed of 1.5 seconds per sheet in the A4 longitudinal direction, thereby obtaining a printed matter.
In the same manner, the temperature of the fixing device was increased by 5 ° C. and fixed, and a printed matter was obtained.
A mending tape (product name: Scotch Mending Tape 810, width 18 mm) is lightly pasted from the margin of the printed material to the image portion, and then a 500 g weight is placed on it, making a round trip at a speed of 10 mm / sec. Pressed. Thereafter, the affixed tape was pressed back and forth once from the lower end side at a peeling angle of 180 degrees and a speed of 10 mm / second. Thereafter, the affixed tape was peeled off from the lower end side at a peeling angle of 180 degrees and a speed of 10 mm / second to obtain a printed matter after the tape was peeled off. 30 sheets of high quality paper (Oki Data Co., Ltd., Excellent White Paper A4 size) is placed under the printed material before and after the tape is applied, and the reflected image density of the fixed image portion before and after the tape is applied to each printed material. , Measured using a colorimeter (GretagMacbeth, trade name: SpectroEye, light conditions; standard light source D50, observation field of view 2 °, density standard DINNB, absolute white standard), and the fixing ratio was calculated from the following formula: did.
Fixing rate = (reflected image density after peeling tape / reflected image density before applying tape) × 100
The temperature at which the fixing rate was 90% or more was defined as the minimum fixing temperature. The lower the minimum fixing temperature, the better the low-temperature fixing property.

[Image density]
Using a commercially available printer (trade name: MicroLine 5400, manufactured by Oki Data Co., Ltd.) on high-quality paper (Fuji Xerox Co., Ltd., J paper A4 size), the toner adhesion amount on the paper is 0.42 to 0.48 mg. A solid image of / cm ² was output to obtain a printed matter.
30 sheets of high quality paper (Oki Data Co., Ltd., Excellent White Paper A4 size) are laid under the printed material, and the reflected image density of the solid image portion of the printed material is measured by a colorimeter (trade name: SpectroEye, Gretag-Macbeth). , Light irradiation conditions; standard light source D50, observation field of view 2 °, density reference DINNB, absolute white reference), and measured values of three arbitrary points on the image were averaged to obtain an image density. The larger the value of the reflected image density, the better the image density.

[Production of polyester]
Production Example 1
(Production of crystalline polyester X1)
The inside of a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple was replaced with nitrogen, and 4350 g of 1,10-decanediol and 5310 g of sebacic acid were added. While stirring, the temperature was raised to 140 ° C., maintained at 140 ° C. for 3 hours, and then heated from 140 ° C. to 200 ° C. over 10 hours. Thereafter, 48 g of di (2-ethylhexanoic acid) tin was added, and the mixture was further maintained at 200 ° C. for 1 hour, and then the pressure in the flask was lowered and maintained at 8.3 kPa for 1 hour to obtain crystalline polyester X1. . Table 1 shows the physical properties of the obtained polyester.

Production Example 2
(Production of crystalline polyester X2)
The inside of a four-necked flask equipped with a nitrogen introducing tube, a dehydrating tube, a stirrer, and a thermocouple was purged with nitrogen, and 4008 g of 1,9-nonanediol, 2900 g of fumaric acid, and 10 g of tert-butylcatechol were added. While stirring, the temperature was raised to 140 ° C., maintained at 140 ° C. for 3 hours, and then heated from 140 ° C. to 200 ° C. over 10 hours. Thereafter, 20 g of di (2-ethylhexanoic acid) tin was added, and the mixture was further maintained at 200 ° C. for 1 hour, and then the pressure in the flask was lowered and maintained at 8.3 kPa for 1 hour to obtain crystalline polyester X2. . Table 1 shows the physical properties of the obtained polyester.

Production Example 3
(Production of crystalline polyester X3)
The inside of a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple was purged with nitrogen, and 1971 g of 1,12-dodecanediol and 2029 g of sebacic acid were added. While stirring, the temperature was raised to 140 ° C., maintained at 140 ° C. for 3 hours, and then heated from 140 ° C. to 200 ° C. over 10 hours. Thereafter, 12 g of di (2-ethylhexanoic acid) tin was added, and the mixture was further maintained at 200 ° C. for 1 hour, and then the pressure in the flask was lowered and maintained at 8.3 kPa for 1 hour to obtain crystalline polyester X3. . Table 1 shows the physical properties of the obtained polyester.

Production Example 4
(Production of amorphous polyester Y1)
The inside of a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple was replaced with nitrogen, and 3374 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, Put 33 g of polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, 672 g of terephthalic acid, and 10 g of dibutyltin oxide, and raise the temperature to 230 ° C. with stirring in a nitrogen atmosphere. After maintaining for 5 hours, the pressure in the flask was further lowered and maintained at 8.3 kPa for 1 hour. Then, after cooling to 210 ° C. and returning to atmospheric pressure, 696 g of fumaric acid and 0.49 g of tert-butylcatechol were added and maintained at a temperature of 210 ° C. for 5 hours. It was maintained at 3 kPa for 4 hours to obtain amorphous polyester Y1. Table 1 shows the physical properties of the obtained polyester.

Production Example 5
(Production of amorphous polyester Y2)
The inside of a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple was replaced with nitrogen, and 3528 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, Polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane (1404 g), terephthalic acid (1248 g), dodecenyl succinic anhydride (1541 g), and dibutyltin oxide (20 g) were added. The temperature was raised to 0 ° C. and maintained at 230 ° C. for 6 hours, and then the pressure in the flask was further lowered and maintained at 8.3 kPa for 1 hour. Then, after cooling to 215 ° C. and returning to atmospheric pressure, 300 g of trimellitic anhydride was added and maintained at 215 ° C. for 1 hour, then the pressure in the flask was further lowered and maintained at 8.3 kPa for 3 hours. As a result, amorphous polyester Y2 was obtained. Table 1 shows the physical properties of the obtained polyester.

Production Example 6
(Production of amorphous polyester Y3)
The inside of a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple was replaced with nitrogen, and 1750 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, A nitrogen atmosphere containing 1625 g of polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, 1145 g of terephthalic acid, 161 g of dodecenyl succinic anhydride, 480 g of trimellitic anhydride, and 10 g of dibutyltin oxide Under stirring, the temperature was raised to 220 ° C. and maintained at 220 ° C. for 5 hours. After confirming that the softening point measured according to ASTM D36-86 reached 120 ° C., the temperature was lowered to stop the reaction. Amorphous polyester Y3 was obtained. Table 1 shows the physical properties of the obtained polyester.

Production Example 7
(Production of amorphous polyester Y4)
The inside of the four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple was replaced with nitrogen, and 3004 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, After adding 996 g of fumaric acid, 2 g of tert-butylcatechol and 8 g of dibutyltin oxide, the temperature was raised to 210 ° C. over 5 hours with stirring in a nitrogen atmosphere, and maintained at 210 ° C. for 2 hours. After maintaining at 8.3 KPa for 1 hour, after confirming that the softening point measured according to ASTM D36-86 reached 100 ° C., the reaction was stopped by lowering the temperature to obtain amorphous polyester Y4 It was. Table 1 shows the physical properties of the obtained polyester.

[Production of resin particles]
Production Example 8
(Production of resin particle dispersion 1)
In a 2 liter stainless steel flask equipped with a stirrer, 600 g of crystalline polyester X1 and a 15% by weight aqueous solution of sodium dodecylbenzenesulfonate (trade name: Neoperex G-15, anionic surfactant, manufactured by Kao Corporation) 120.0 g, polyoxyethylene lauryl ether (manufactured by Kao Corporation, trade name: Emulgen 150, nonionic surfactant) 25.6 g, and 56.0% by weight potassium hydroxide aqueous solution 276.0 g were added and stirred. The mixture was heated to 85 ° C., melted, and mixed at 85 ° C. for 2 hours. Next, while maintaining the temperature of the system at 85 ° C., 1137.8 g of deionized water was added dropwise at a rate of 6 g / min while stirring to obtain an emulsion. The obtained emulsion was cooled, and 28 g of an oxazoline group-containing polymer aqueous solution (manufactured by Nippon Shokubai Co., Ltd., trade name: Epocross WS-700, nonvolatile content 25 wt%, acrylic main chain) was added while stirring at 25 ° C. Then, the temperature was raised to 95 ° C. and held at 95 ° C. for 1 hour. Next, the mixture was cooled to 25 ° C., and the obtained emulsion was passed through a 200 mesh (mesh 105 μm) wire mesh to obtain a resin particle dispersion 1.
The solid content concentration of the resin particle dispersion 1 was 31%, the volume median particle size (D ₅₀ ) of the resin particles in the resin particle dispersion 1 was 153 nm, and the CV value was 27%.

Production Example 9
(Production of resin particle dispersion 2)
A resin particle dispersion 2 was obtained in the same manner as in Production Example 8, except that the crystalline polyester X1 was changed to the crystalline polyester X2.
The solid content concentration of the resin particle dispersion 2 was 31%, the volume median particle size (D ₅₀ ) of the resin particles in the resin particle dispersion 2 was 319 nm, and the CV value was 27%.

Production Example 10
(Production of resin particle dispersion 3)
Resin particle dispersion 3 was obtained in the same manner as in Production Example 8, except that crystalline polyester X1 was changed to crystalline polyester X3.
The solid content concentration of the resin particle dispersion 3 was 31%, the volume median particle size (D ₅₀ ) of the resin particles in the resin particle dispersion 3 was 214 nm, and the CV value was 32%.

Production Example 11
(Production of resin particle dispersion 4)
In Production Example 8, a resin particle dispersion 4 was obtained in the same manner except that the crystalline polyester X1 was changed to the crystalline polyester X2, and the addition of the oxazoline group-containing polymer aqueous solution and the temperature holding at 95 ° C. were not performed.
The solid content concentration of the resin particle dispersion 4 was 31%, the volume median particle size (D ₅₀ ) of the resin particles in the resin particle dispersion 4 was 160 nm, and the CV value was 28%.

Production Example 12
(Production of resin particle dispersion 5)
Resin particle dispersion 5 was obtained in the same manner as in Production Example 8, except that 45 g of copper phthalocyanine pigment (trade name: ECB301, manufactured by Dainichi Seika Kogyo Co., Ltd.) was added in addition to 600 g of crystalline polyester X1.
The solid content concentration of the resin particle dispersion 5 was 31%, the volume median particle size (D ₅₀ ) of the resin particles in the resin particle dispersion 5 was 185 nm, and the CV value was 28%.

Production Example 13
(Production of resin particle dispersion 6)
In a flask equipped with a stirrer, 210 g of amorphous polyester Y2, 300 g of amorphous polyester Y1, 90 g of crystalline polyester X1, 45 g of copper phthalocyanine pigment (trade name: ECB301, manufactured by Dainichi Seika Kogyo Co., Ltd.), polyoxy Ethylene alkyl ether (nonionic surfactant, trade name: Emulgen 150, manufactured by Kao Corporation) 8.5 g, 15% by weight aqueous sodium dodecylbenzenesulfonate (anionic surfactant, trade name: Neoperex G-) (15, manufactured by Kao Corporation) 80.0 g, 278.5 g of 5 wt% aqueous potassium hydroxide solution were added, and the mixture was heated to 95 ° C. with stirring and melted, and mixed at 95 ° C. for 2 hours to obtain a resin mixture. Got.
Next, while maintaining the temperature of the system at 95 ° C., 1222 g of deionized water was added dropwise at a rate of 6 g / min while stirring to obtain an emulsion. Next, the obtained emulsion was cooled to 25 ° C., and stirred at 25 ° C., while stirring the oxazoline group-containing polymer aqueous solution (trade name: Epocross WS-700, manufactured by Nippon Shokubai Co., Ltd., nonvolatile content 25% by weight, acrylic 28 g of the main chain) was added, and then the temperature was raised to 95 ° C. and held at 95 ° C. for 1 hour. Next, the mixture was cooled to 25 ° C., and the obtained emulsion was passed through a 200 mesh (mesh opening 105 μm) wire mesh to obtain a resin particle dispersion 6. The solid content concentration was 32%, the volume median particle size (D ₅₀ ) of the resin particles was 320 nm, and the CV value was 25%.

Production Example 14
(Production of resin particle dispersion 7)
In a flask having an internal volume of 5 liters, amorphous polyester Y2 210 g, amorphous polyester Y1 390 g, copper phthalocyanine pigment (manufactured by Dainichi Seika Kogyo Co., Ltd., trade name: ECB301), polyoxyethylene alkyl ether (nonionic) Surfactant, trade name: Emulgen 430, manufactured by Kao Corp.) 6 g, 15 wt% sodium dodecylbenzenesulfonate aqueous solution (anionic surfactant, manufactured by Kao Corp., trade name: Neoperex G-15) 40 g and 268 g of 5 wt% potassium hydroxide were added, and the mixture was heated to 95 ° C. and melted with stirring, and mixed at 95 ° C. for 2 hours to obtain a resin mixture.
Next, 1146 g of deionized water was added dropwise at a rate of 6 g / min while stirring to obtain an emulsion. The obtained emulsion was cooled to 25 ° C. and passed through a 200 mesh (mesh opening 105 μm) wire mesh to obtain a resin particle dispersion 7. The resulting dispersion had a solid content concentration of 32% by weight, a volume median particle size (D ₅₀ ) of 180 nm, and a CV value of 28%.

Production Example 15
(Production of resin particle dispersion 8)
In a flask having an internal volume of 5 liters, amorphous polyester Y3 210 g, amorphous polyester Y1 390 g, polyoxyethylene alkyl ether (nonionic surfactant, trade name: Emulgen 430, manufactured by Kao Corporation) 6 g, 15 40% by weight of sodium dodecylbenzenesulfonate aqueous solution (anionic surfactant, manufactured by Kao Corporation, trade name: Neoperex G-15) and 268 g of 5% by weight potassium hydroxide were added and the temperature was raised to 95 ° C. with stirring. The mixture was warmed and melted and mixed at 95 ° C. for 2 hours to obtain a resin mixture.
Next, 1145 g of deionized water was added dropwise at a rate of 6 g / min while stirring to obtain an emulsion. The obtained emulsion was cooled to 25 ° C., passed through a 200-mesh wire mesh, deionized water was added to adjust the solid content to 23% by weight, and a resin particle dispersion 8 containing amorphous polyester was obtained. Obtained. The glass transition point of the resin particles in the dispersion was 60 ° C., the volume median particle size (D ₅₀ ) was 158 nm, and the CV value was 24%.

Production Example 16
(Production of resin particle dispersion 9)
Resin particle dispersion 9 was obtained in the same manner as in Production Example 14 except that 210 g of amorphous polyester Y2 and 390 g of amorphous polyester Y1 were changed to 600 g of amorphous polyester Y4.
The solid content concentration of the resin particle dispersion 9 was 31%, the volume median particle size (D ₅₀ ) of the resin particles in the resin particle dispersion 9 was 162 nm, and the CV value was 26%.

Production Example 17
(Production of resin particle dispersion 10)
A resin particle dispersion 10 was obtained in the same manner as in Production Example 15, except that 210 g of amorphous polyester Y3 and 390 g of amorphous polyester Y1 were changed to 600 g of amorphous polyester Y4 in Production Example 15.
The solid content concentration of the resin particle dispersion 10 was 31%, the volume median particle size (D ₅₀ ) of the resin particles in the resin particle dispersion 10 was 128 nm, and the CV value was 24%.

Production Example 18
(Production of resin particle dispersion 11)
A resin particle dispersion 11 was obtained in the same manner as in Production Example 14, except that 45 g of the copper phthalocyanine pigment in Production Example 14 was changed to 33 g.
The solid content concentration of the resin particle dispersion 11 was 32%, the volume median particle size (D ₅₀ ) of the resin particles in the resin particle dispersion 11 was 175 nm, and the CV value was 27%.

Production Example 19
(Production of resin particle dispersion 12)
In Production Example 14, a resin particle dispersion 12 was obtained in the same manner as in Production Example 14 except that the copper phthalocyanine pigment was not added. The solid content concentration of the resin particle dispersion 12 was 31%, the volume median particle size (D ₅₀ ) was 134 nm, and the CV value was 25%.

Production Example 20
(Production of release agent particle dispersion)
2. In a 1 liter beaker, sodium acrylate-sodium maleate copolymer aqueous solution (trade name: Poise 521, effective concentration 40% by weight, manufactured by Kao Corporation) as a sodium polycarboxylate aqueous solution in 200 g of deionized water After 8 g was dissolved, 5 g of carnauba wax (manufactured by Hiroyuki Kato, product name: carnauba wax No. 1, melting point 83 ° C.) and paraffin wax (manufactured by Nippon Seiki Co., Ltd., product name: HNP) −9, melting point 75 ° C.) 45 g was added, and the mixture was melted while maintaining the temperature at 90 to 95 ° C. to obtain a molten mixture in which carnauba wax and paraffin wax were melted together.
The aqueous solution containing the obtained molten mixture was further subjected to a dispersion treatment for 30 minutes with an ultrasonic homogenizer (manufactured by Nippon Seiki Co., Ltd., trade name: US-600T) while maintaining the temperature at 90 to 95 ° C. Then, ion-exchanged water was added thereto to adjust the release agent solid content to 20% by weight to obtain a release agent particle dispersion. The volume median particle size (D ₅₀ ) of the release agent particles in the release agent particle dispersion was 450 nm, the CV value was 30%, and the melting point was 75 ° C.

Production Example 21
(Production of colorant particle dispersion)
Copper phthalocyanine pigment (trade name: ECB301, manufactured by Dainichi Seika Kogyo Co., Ltd.) 60 g, 15% by weight sodium dodecylbenzenesulfonate aqueous solution (anionic surfactant, manufactured by Kao Corporation, trade name: 2 L beaker Neoperex G-15) 80 g and deionized water 112 g were added and mixed for 20 minutes at 5000 rpm using a homomixer (Primics Co., Ltd. 2M-03 type). Furthermore, this mixed liquid was subjected to a dispersion treatment for 20 minutes with an ultrasonic homogenizer (manufactured by Nippon Seiki Co., Ltd., trade name: US-600T) to obtain a colorant particle dispersion. The volume median particle size (D ₅₀ ) of the colorant particles in the obtained colorant particle dispersion was 150 nm, the CV value was 31%, and the solid content concentration was 26%.

[Production of toner]
Example 1
(Manufacture of toner A)
Into a 3 liter four-necked flask equipped with a dehydration tube, a stirrer and a thermocouple, are placed 212 g of resin particle dispersion 7, 38 g of resin particle dispersion 1, 71 g of deionized water, and 18 g of release agent particle dispersion. And mixed at 25 ° C. Next, with stirring at 25 ° C., an aqueous solution in which 20.1 g of ammonium sulfate was dissolved in 196 g of deionized water was dropped into this mixture over 30 minutes. Subsequently, the obtained liquid mixture was heated up to 55 degreeC and hold | maintained at 55 degreeC, and the dispersion liquid containing the aggregated particle whose volume median particle diameter is 4.5 micrometers was obtained (process (1)).
Subsequently, after the dispersion was adjusted to 52 ° C., a mixed liquid obtained by mixing 115 g of the resin particle dispersion 8 and 36 g of deionized water was dropped into the dispersion over 300 minutes. In this step, the dispersion containing the aggregated particles was heated from 52 ° C. at a rate of 1 ° C./60 minutes. As a result, a dispersion containing aggregated particles having a volume-median particle size of 5.4 μm was obtained (step (2)).
After adding an aqueous solution obtained by mixing 18 g of sodium polyoxyethylene lauryl ether sulfate (trade name: EMAL E27C, solid content: 28% by weight) and 1397 g of deionized water to the obtained dispersion, 2 The temperature was raised to 63 ° C. over time. Next, 1 mol / L sulfuric acid was added dropwise to the dispersion at 63 ° C. to adjust the pH of the dispersion to 5.7, and then held at 63 ° C. for 3 hours, and the fused particles having a volume median particle size of 5.3 μm. Got. Then, it cooled to 25 degreeC. (Process (3))
The obtained fused particles were filtered, dried, and washed to obtain toner particles. To 100 parts by weight of the toner particles, hydrophobic silica (manufactured by Nippon Aerosil Co., Ltd., trade name: RY50, number average particle size; 0.04 μm), 2.5 parts by weight, hydrophobic silica (manufactured by Cabot Corporation, product) Name: Cabosea TS720, number average particle size: 0.012 μm) 1.0 part by weight, and polymer fine particles (manufactured by Nippon Paint Co., Ltd., trade name: Finesphere P2000, number average particle size: 0.5 μm) 0.8 Part by weight was externally added with a Henschel mixer and passed through a 150-mesh sieve to obtain toner A. Table 2 shows the physical properties and evaluation of the obtained toner.

Examples 2, 3, 5, 6 and Comparative Examples 1-3
(Production of toners B, C and E to I)
In Example 1, toners B, C, and E to I were obtained in the same manner as in Example 1 except that the fusing temperature of the resin particle dispersion and the aggregated particles used was changed as shown in Table 2. Table 2 shows the physical properties and evaluation of the obtained toner.

Example 4
(Manufacture of toner D)
In Example 1, a toner D was obtained in the same manner as in Example 1 except that the step (1) was performed as follows. Table 2 shows the physical properties and evaluation of the obtained toner.
In a 3 liter four-necked flask equipped with a dehydration tube, a stirrer and a thermocouple, 212 g of resin particle dispersion 4, 38 g of resin particle dispersion 7, 60 g of deionized water, 18 g of release agent particle dispersion, 11 g of 15% by weight aqueous sodium dodecylbenzenesulfonate solution (anionic surfactant, manufactured by Kao Corporation, trade name: Neoperex G-15) was added and mixed at 25 ° C. Thereafter, an aqueous solution obtained by dissolving 20.1 g of ammonium sulfate in 196 g of deionized water was dropped into the mixture over 30 minutes while stirring. Subsequently, the obtained liquid mixture was heated up to 55 degreeC and hold | maintained at 55 degreeC, and the dispersion liquid containing the aggregated particle whose volume median particle diameter is 4.2 micrometers was obtained (process (1)).

Comparative Example 4
(Manufacture of toner J)
In the same manner as in Example 1, except that the resin particle dispersion 7 is changed to the resin particle dispersion 12, and 71 g of deionized water is changed to 46 g of deionized water and 34 g of the colorant particle dispersion, toner J Got. Table 2 shows the physical properties and evaluation of the obtained toner.

  From Table 2, the electrostatic charge image developing toners of the examples are superior in color density since they are excellent in image density, low-temperature fixability and heat-resistant storage stability as compared with the electrostatic charge image developing toners in the comparative examples. It can be seen that the printed image has a high image density, excellent fixability, and excellent storage stability at high temperatures.

  The electrostatic image developing toner obtained by the production method of the present invention is excellent in image density and can achieve both low-temperature fixability and heat-resistant storage stability. Therefore, it can be suitably used as an electrostatic image developing toner used in electrophotography. . According to the method of the present invention, a toner having such characteristics can be produced efficiently.

Claims (8)

A method for producing a core-shell type electrostatic image developing toner comprising the following steps (1) to (3):
Step (1): Resin particles (A) made of crystalline polyester (a), resin particles (B) containing a colorant and amorphous polyester (b), and release agent particles containing a release agent Step of aggregating to obtain aggregated particles (1) Step (2): Step of adding resin particles (C) containing amorphous polyester (c) to obtain aggregated particles (2) Step (3): The agglomerated particles (2) are at a temperature not less than 10 ° C. lower than the glass transition point of the amorphous polyester (b) and not less than 10 ° C. lower than the glass transition point of the amorphous polyester (c). A step of obtaining fused core-shell particles by maintaining the temperature below the melting point of the crystalline polyester (a).   The method for producing a toner for developing an electrostatic charge image according to claim 1, wherein the crystalline polyester (a) has a melting point of 60 to 90 ° C.   The method for producing a toner for developing an electrostatic charge image according to claim 1, wherein the resin particles (A) are crosslinked with a compound having an oxazoline group.   The crystalline polyester (a) is a crystalline polyester obtained by condensation polymerization of an α, ω-alkanediol having 4 to 12 carbon atoms and an aliphatic dicarboxylic acid having 8 to 12 carbon atoms. A method for producing a toner for developing an electrostatic image according to any one of the above.   The method for producing a toner for developing an electrostatic charge image according to any one of claims 1 to 4, wherein the amorphous polyester (b) has a glass transition point of 50 to 70 ° C.   The method for producing a toner for developing an electrostatic charge image according to any one of claims 1 to 5, wherein the glass transition point of the amorphous polyester (b) is lower than the melting point of the crystalline polyester (a).   The method for producing a toner for developing an electrostatic charge image according to any one of claims 1 to 6, wherein the release agent comprises two or more release agents having a melting point of 60 to 90 ° C.   The electrostatic charge in any one of Claims 1-7 whose content of the coloring agent in a resin particle (B) is 1-20 weight part with respect to 100 weight part of resin which comprises the resin particle (B). A method for producing a toner for image development.