JP2025076030A - Electrostatic image developing toner - Google Patents

Abstract

To provide an electrostatic image developing toner capable of producing printed matter with high image density.SOLUTION: An electrostatic image developing toner comprising a binder resin and a colorant is provided, the binder resin containing an amorphous polyester resin A with an ester group concentration of 5.0 to 12.0 mmol/g, inclusive, and the colorant being C.I. Pigment Red 254.SELECTED DRAWING: None

Description

The present invention relates to a toner for developing electrostatic images used to develop latent images formed in electrophotography, electrostatic recording, electrostatic printing, etc.

In the field of electrophotography, with the advancement of electrophotographic systems, there is a demand for the development of electrophotographic toners that can handle higher image quality and faster speeds. To meet this demand, there is a need for toners that can produce printed matter with high image density.

Patent Document 1 describes a magenta toner that contains at least a binder resin and a colorant, and is characterized in that in a spectral distribution diagram with reflectance (%) on the vertical axis and wavelength (nm) on the horizontal axis, the reflectance measured for the toner in a powder state is in the range of 5 to 10% at a wavelength of 425 nm and 65 to 70% at a wavelength of 675 nm, for the purpose of providing a magenta toner that can cover the magenta tone of process inks by using a specific pigment in combination, has high coloring power that covers a wide dynamic range from low to high density, has high saturation and brightness, has excellent transparency for OHP, and has high light resistance.

JP 2003-280278 A

Since C.I. Pigment Red 254 has a bright color tone and is highly safe, it is desirable to use it as a colorant to improve the performance of toners for developing electrostatic images. The inventors have found that when C.I. Pigment Red 254 is used as a colorant in the magenta toner described in Patent Document 1, it cannot be sufficiently dispersed in the toner, and there is a risk that a printed matter with excellent image density cannot be obtained using the toner.
The present invention relates to a toner for developing electrostatic images, which is capable of obtaining printed matter having high image density.

The present inventors have found that by using a binder resin containing an amorphous polyester resin having a relatively high ester group concentration in a specific range, a toner for developing electrostatic images that can realize a printed matter having a high image density can be obtained even when C.I. Pigment Red 254 is used as a colorant.
The present invention relates to the following [1].
[1] A toner for developing electrostatic images, comprising a binder resin and a colorant,
the binder resin contains an amorphous polyester resin A having an ester group concentration of 5.0 mmol/g or more and 12.0 mmol/g or less,
The colorant is C.I. Pigment Red 254;
Toner for developing electrostatic images.

The present invention provides a toner for developing electrostatic images that can produce printed matter with high image density.

[Toner for developing electrostatic images]
The toner for developing electrostatic images of the present invention (hereinafter, also simply referred to as "toner") contains a binder resin and a colorant.
The binder resin contains an amorphous polyester resin A (hereinafter, also simply referred to as "resin A") having an ester group concentration of 5.0 mmol/g or more and 12.0 mmol/g or less.
The colorant is C.I. Pigment Red 254.
Due to the above-mentioned characteristics, the toner for developing electrostatic images of the present invention can be used to obtain printed matter having high image density.
Incidentally, toner particles containing a binder resin and a colorant (hereinafter, also simply referred to as "toner particles") can be used as they are as the toner of the present invention, but it is preferable to use as the toner particles those in which a fluidizing agent or the like is added as an external additive to the surface of the toner particles.

The mechanism by which a printed matter having a high image density can be obtained by using the toner of the present invention is not clear, but is thought to be as follows.
C.I. Pigment Red 254 has a diketopyrrolopyrrole skeleton, is highly planar, and has a chlorine atom and an amide bond, so it is prone to aggregation due to intramolecular interactions. Therefore, C.I. Pigment Red 254 is difficult to disperse in toner particles, which causes a decrease in the image density of a printed matter produced using the resulting toner. In the present invention, an amorphous polyester resin A having a high ester group concentration is used as the binder resin. By increasing the ester group concentration, the affinity between the polyester resin having an increased polarity and C.I. Pigment Red 254 is improved, the interaction between C.I. Pigment Red 254 itself is alleviated, and C.I. Pigment Red 254 is easily dispersed in the polyester resin, and C.I. Pigment Red 254 can be uniformly incorporated into the toner particles. As a result, it is considered that a printed matter having a high image density can be obtained using the toner of the present invention.
It should be noted that the above-mentioned mechanism regarding the effect of the present invention is merely a presumption, and the present invention is not limited thereto.

The definitions of various terms used in this specification are given below.
In the specification, the carboxylic acid component of the polyester resin includes not only the compound itself but also anhydrides that decompose during the reaction to produce a carboxylic acid, and alkyl esters of each carboxylic acid (alkyl groups having 1 to 3 carbon atoms).
Whether a resin is crystalline or amorphous is determined by the crystallinity index. The crystallinity index is defined as the ratio of the softening point of the resin to the maximum endothermic peak temperature (softening point (°C)/maximum endothermic peak temperature (°C)) in the measurement method described in the examples below. A crystalline resin is one having a crystallinity index of 0.6 or more and 1.4 or less. An amorphous resin is one in which no endothermic peak is observed, or if an endothermic peak is observed, the crystallinity index is less than 0.6 or more than 1.4. The crystallinity index can be appropriately adjusted by the type and ratio of raw material monomers, as well as production conditions such as reaction temperature, reaction time, and cooling rate.
The term "(meth)acrylic acid" refers to at least one selected from acrylic acid and methacrylic acid.
The term "(meth)acrylate" refers to at least one selected from acrylate and methacrylate.

[Toner Particles]
The toner of the present invention contains toner particles, and the toner particles contain a binder resin and a colorant.

<Binder resin>
The binder resin contains an amorphous polyester resin A (hereinafter, also simply referred to as "resin A") having an ester group concentration of 5.0 mmol/g or more and 12.0 mmol/g or less.

From the viewpoint of dispersing C.I. Pigment Red 254 in the toner to improve the image density of the printed matter, the amorphous polyester resin A has an ester group concentration of 5.0 mmol/g or more and 12.0 mmol/g or less, preferably 5.5 mmol/g or more, more preferably 6.5 mmol/g or more, and even more preferably 7.5 mmol/g or more, and from the viewpoint of production efficiency, preferably 10.0 mmol/g or less. The ester group concentration of the amorphous polyester resin A is calculated by the following formula.

(In the formula, A is the total amount (mol) of ester bonds produced when all the raw material monomers of the amorphous polyester resin A are reacted, and B is the total mass (g) of the raw material monomers constituting the amorphous polyester resin A. The numbers in parentheses in the formula indicate the units of each value.)
The ester group concentration of the amorphous polyester resin A can be appropriately adjusted by adjusting the types and amounts of the raw material monomers used, as well as production conditions such as reaction temperature, reaction time, and cooling rate.
When two or more kinds of resins are mixed and used as the amorphous polyester resin A, the weighted average of the ester group concentrations of the respective amorphous polyester resins A is defined as the ester group concentration of the amorphous polyester resin A.

(Amorphous polyester resin A)
The amorphous polyester resin A is a polycondensation product of an alcohol component (a) and a carboxylic acid component (b).
The alcohol component (a) preferably contains an aliphatic diol.

The aliphatic diol preferably has 2 or more carbon atoms, and preferably has 16 or less carbon atoms, more preferably 12 or less carbon atoms, and further preferably 8 or less carbon atoms.
Examples of the aliphatic diol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2-methyl-1,3-propanediol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 2,3-pentanediol, 2,4-pentanediol, neopentyl glycol, 2-ethyl-2- Examples of the alkyl ether include methyl-1,3-propanediol, 2-methyl-1,4-butanediol, 2-ethyl-1,4-butanediol, 2,2-dimethyl-1,4-butanediol, 2,3-dimethyl-1,4-butanediol, 2-methyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, and 1,12-dodecanediol. Among these, ethylene glycol, 1,2-propanediol, 2,3-butanediol, and neopentyl glycol are preferred, and ethylene glycol and neopentyl glycol are more preferred.
These aliphatic diols may be used alone or in combination of two or more.

In order to obtain a desired ester group concentration, the content of the aliphatic diol in the alcohol component (a) is preferably 30 mol% or more, more preferably 50 mol% or more, even more preferably 70 mol% or more, even more preferably 80 mol% or more, even more preferably 90 mol% or more, and 100 mol% or less.

From the viewpoint of image density of the printed matter, the content of neopentyl glycol in the alcohol component (a) is preferably 35 mol% or more, more preferably 55 mol% or more, even more preferably 75 mol% or more, even more preferably 90 mol% or more, and 100 mol% or less.

Examples of the alcohol component (a) other than the aliphatic diol include alkylene oxide adducts of aromatic diols and trihydric or higher polyhydric alcohols.
Examples of the alkylene oxide adduct of an aromatic diol include those represented by the formula (I):

(wherein OR and RO are oxyalkylene groups, each R is independently an ethylene or propylene group, x and y are the average number of moles of alkylene oxide added and are each positive numbers, and the sum of x and y is 1 or more, preferably 1.5 or more, and 16 or less, preferably 8 or less, more preferably 4 or less).
Examples of the alkylene oxide adduct of bisphenol A represented by formula (I) include a propylene oxide adduct of 2,2-bis(4-hydroxyphenyl)propane, and an ethylene oxide adduct of 2,2-bis(4-hydroxyphenyl)propane.
These aromatic diols may be used alone or in combination of two or more.

When the alcohol component (a) contains an aromatic diol, the content of the aromatic diol in the alcohol component (a) is preferably 20 mol% or more, more preferably 30 mol% or more, and preferably 60 mol% or less, more preferably 50 mol% or less, from the viewpoint of obtaining a desired ester group concentration.

Examples of trihydric or higher polyhydric alcohols include glycerin, pentaerythritol, trimethylolpropane, and sorbitol.
These trihydric or higher polyhydric alcohols may be used alone or in combination of two or more.

Examples of the carboxylic acid component (b) include aromatic dicarboxylic acids, aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and tri- or higher carboxylic acids.
Among these, the carboxylic acid component (b) preferably contains an aromatic dicarboxylic acid from the viewpoint of obtaining a desired ester group concentration.
From the above viewpoint, the aromatic dicarboxylic acid is more preferably at least one selected from terephthalic acid and isophthalic acid, and further preferably contains terephthalic acid and isophthalic acid.
From the viewpoint of obtaining an amorphous polyester resin A having a desired ester group concentration in the carboxylic acid component (b), the content of the aromatic dicarboxylic acid is preferably 60 mol% or more, more preferably 70 mol% or more, even more preferably 80 mol% or more, and is preferably 100 mol% or less, more preferably 100 mol%.

Examples of the aliphatic dicarboxylic acid include oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, adipic acid, succinic acid, and succinic acid which may be substituted with an aliphatic hydrocarbon group having 1 to 20 carbon atoms.
Examples of succinic acid substituted with an aliphatic hydrocarbon group having from 1 to 20 carbon atoms include octyl succinic acid and dodecenyl succinic acid (tetrapropenyl succinic acid).
An example of the alicyclic dicarboxylic acid is cyclohexanedicarboxylic acid.

Examples of trivalent or higher carboxylic acids include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, and pyromellitic acid. Among these, trimellitic acid and its anhydride are preferred.
The alcohol component (a) may appropriately contain a monohydric alcohol, and the carboxylic acid component (b) may appropriately contain a monobasic carboxylic acid.

The equivalent ratio of the carboxyl groups of the carboxylic acid component to the hydroxyl groups of the alcohol component (a) [COOH groups/OH groups] is preferably 0.7 or more, more preferably 0.8 or more, and is preferably 1.3 or less, more preferably 1.2 or less.

(Method for producing amorphous polyester resin A)
Resin A can be produced, for example, by polycondensing raw material monomers including an alcohol component (a) and a carboxylic acid component (b).

The polycondensation of the alcohol component (a) and the carboxylic acid component (b) can be carried out, for example, in an inert gas atmosphere, in the presence of an esterification catalyst, an esterification promoter, a polymerization inhibitor, etc., as necessary, at a temperature of about 120° C. or higher and 250° C. or lower.
Examples of the esterification catalyst include tin compounds such as dibutyltin oxide and tin(II) di(2-ethylhexanoate), and titanium compounds such as titanium diisopropoxybis(triethanolaminate). Examples of the esterification promoter that can be used together with the esterification catalyst include gallic acid.
The amount of the esterification catalyst used is preferably 0.01 parts by mass or more and 10 parts by mass or less per 100 parts by mass of the total amount of the alcohol component (a) and the carboxylic acid component (b) which are raw material monomers for the resin A.
The amount of the esterification promoter used is preferably 0.001 part by mass or more and 1 part by mass or less per 100 parts by mass of the total amount of the alcohol component (a) and the carboxylic acid component (b).
Furthermore, examples of the polymerization inhibitor include radical polymerization inhibitors such as 4-tert-butylcatechol.
When a polymerization inhibitor is used, the amount of the polymerization inhibitor used is preferably 0.001 part by mass or more and 1 part by mass or less per 100 parts by mass of the total amount of the alcohol component (a) and the carboxylic acid component (b).

(Physical Properties of Amorphous Polyester Resin A)
From the viewpoint of heat-resistant storage stability, the softening point of Resin A is preferably 70° C. or higher, more preferably 80° C. or higher, and even more preferably 90° C. or higher, and from the viewpoint of low-temperature fixability, it is preferably 130° C. or lower, more preferably 120° C. or lower, and even more preferably 110° C. or lower.
The glass transition temperature of Resin A is preferably 30° C. or higher, more preferably 35° C. or higher, and even more preferably 40° C. or higher, from the viewpoint of heat-resistant storage stability, and is preferably 80° C. or lower, more preferably 70° C. or lower, and even more preferably 65° C. or lower, from the viewpoint of low-temperature fixability.

The acid value of Resin A is preferably 5 mgKOH/g or more, more preferably 8 mgKOH/g or more, even more preferably 10 mgKOH/g or more, and is preferably 40 mgKOH/g or less, more preferably 30 mgKOH/g or less, even more preferably 25 mgKOH/g or less.
The softening point, glass transition temperature, and acid value of Resin A can be appropriately adjusted by the types and amounts of raw material monomers used, as well as production conditions such as reaction temperature, reaction time, and cooling rate. The softening point, glass transition temperature, and acid value of Resin A can be determined by the method described in the Examples.
When two or more resins A are used in combination, the softening point, glass transition temperature and acid value of the resulting mixture are preferably within the above-mentioned ranges.

(Amorphous resin B)
The binder resin may contain an amorphous resin B (hereinafter, simply referred to as "resin B") other than resin A, as long as the effects of the present invention are not impaired. Examples of resin B include an amorphous polyester resin and a styrene-acrylic resin having an ester group concentration of less than 5.0 mmol/g.

(Crystalline polyester resin C)
From the viewpoint of image density of the printed matter, the binder resin preferably contains crystalline polyester resin C (hereinafter, also simply referred to as "resin C").
The crystalline polyester resin C is a polycondensation product of an alcohol component and a carboxylic acid component.
The alcohol component is preferably an α,ω-aliphatic diol.
The α,ω-aliphatic diol preferably has 2 or more carbon atoms, more preferably 4 or more, and even more preferably 6 or more carbon atoms, and preferably has 16 or less, more preferably 14 or less, and even more preferably 12 or less carbon atoms.
Examples of α,ω-aliphatic diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, and 1,14-tetradecanediol. Among these, ethylene glycol, 1,6-hexanediol, 1,10-decanediol, and 1,12-dodecanediol are preferred, and 1,10-decanediol is more preferred.

The amount of α,ω-aliphatic diol in the alcohol component is preferably 80 mol% or more, more preferably 85 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, and is 100 mol% or less, preferably 100 mol%.

The alcohol component may contain other alcohol components different from the α,ω-aliphatic diol. Examples of other alcohol components include aliphatic diols other than α,ω-aliphatic diols, such as 1,2-propanediol and neopentyl glycol; aromatic diols such as alkylene oxide adducts of bisphenol A; and trihydric or higher alcohols, such as glycerin, pentaerythritol, and trimethylolpropane. These alcohol components may be used alone or in combination of two or more.

The carboxylic acid component is preferably an aliphatic dicarboxylic acid, more preferably a straight-chain aliphatic dicarboxylic acid.
The aliphatic dicarboxylic acid preferably has 4 or more carbon atoms, more preferably 8 or more, and even more preferably 10 or more carbon atoms, and preferably has 14 or less, and more preferably 12 or less carbon atoms.
Examples of the aliphatic dicarboxylic acid include fumaric acid, sebacic acid, dodecanedioic acid, and tetradecanedioic acid. Among these, sebacic acid and dodecanedioic acid are preferred, and sebacic acid is more preferred. These carboxylic acid components may be used alone or in combination of two or more.

The amount of aliphatic dicarboxylic acid in the carboxylic acid component is preferably 80 mol% or more, more preferably 85 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, and is 100 mol% or less, preferably 100 mol%.

The carboxylic acid component may contain other carboxylic acid components different from the aliphatic dicarboxylic acid. Examples of other carboxylic acid components include aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid; and polyvalent carboxylic acids having three or more valences. These carboxylic acid components may be used alone or in combination of two or more.

The equivalent ratio of the carboxyl groups of the carboxylic acid component to the hydroxyl groups of the alcohol component [COOH groups/OH groups] is preferably 0.7 or more, more preferably 0.8 or more, and is preferably 1.3 or less, more preferably 1.2 or less.

The method for producing resin C can be, for example, the same as that for resin A, which is the polyester resin described above.

(Physical Properties of Crystalline Polyester Resin C)
From the viewpoint of the storage stability of the toner, the softening point of resin C is preferably 60° C. or higher, more preferably 70° C. or higher, and even more preferably 80° C. or higher, and from the viewpoint of further improving the low-temperature fixing ability, it is preferably 150° C. or lower, more preferably 120° C. or lower, and even more preferably 100° C. or lower.
From the viewpoint of the storage stability of the toner, the melting point of resin C is preferably 50° C. or higher, more preferably 60° C. or higher, and even more preferably 70° C. or higher, and from the viewpoint of further improving the low-temperature fixing property, it is preferably 100° C. or lower, more preferably 90° C. or lower, and even more preferably 80° C. or lower.

The acid value of resin C is preferably 5 mgKOH/g or more, more preferably 10 mgKOH/g or more, and preferably 35 mgKOH/g or less, more preferably 25 mgKOH/g or less, and even more preferably 20 mgKOH/g or less.
The softening point, melting point and acid value of the resin C can be appropriately adjusted by the type and amount of the raw material monomer, as well as production conditions such as reaction temperature, reaction time and cooling rate, and are determined by the method described in the Examples below. When two or more types of resin C are used in combination, it is preferable that the softening point, melting point and acid value obtained as a mixture thereof are each within the above-mentioned ranges.

From the viewpoint of image density of the printed matter, the content of the binder resin in the toner particles is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 75% by mass or more, and preferably 99% by mass or less, more preferably 97% by mass or less, even more preferably 95% by mass or less.

From the viewpoint of image density of the printed matter, the content of resin A in the binder resin is preferably 50% by mass or more, more preferably 70% by mass or more, and is preferably 97% by mass or less, more preferably 95% by mass or less, and even more preferably 90% by mass or less.
From the viewpoint of image density of the printed matter, the content of resin C in the binder resin is preferably 3% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, and is preferably 50% by mass or less, more preferably 30% by mass or less.

From the viewpoint of image density of the printed matter, the total content of resin A and resin C in the binder resin is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, and is 100% by mass or less, preferably 100% by mass.

From the viewpoint of low-temperature fixing property, the mass ratio of resin C to resin A in the toner particles [resin C/resin A] is preferably 0.03 or more, more preferably 0.05 or more, even more preferably 0.07 or more, and is preferably 1 or less, more preferably 0.5 or less, even more preferably 0.4 or less, even more preferably 0.3 or less.

<Coloring Agent>
In the present invention, the toner particles contain a colorant, and the colorant is C.I. Pigment Red 254.

The content of the colorant in the toner particles is preferably 1% by mass or more, more preferably 2% by mass or more, and preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less.

The content of the colorant is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more, based on 100 parts by mass of the total of Resin A and Resin C, from the viewpoint of improving dispersibility in the toner particles, and is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less.

In addition, the toner particles may contain a colorant other than C.I. Pigment Red 254, as long as the effect of the present invention is not impaired. The content of the colorant in the toner particles is, for example, 5% by mass or less, preferably 3% by mass or less, more preferably 1% by mass or less, and is 0% by mass.

<Release Agent>
The toner particles preferably contain a release agent.
Examples of the release agent include polypropylene wax, polyethylene wax, ethylene propylene copolymer wax, hydrocarbon wax such as microcrystalline wax, paraffin wax, Fischer-Tropsch wax, or oxides thereof, ester wax such as carnauba wax, montan wax, or deacidified wax thereof, or fatty acid ester wax, fatty acid amides, fatty acids, higher alcohols, and fatty acid metal salts. These may be used alone or in combination of two or more.

The melting point of the release agent is preferably 60° C. or higher, more preferably 70° C. or higher, and preferably 160° C. or lower, more preferably 140° C. or lower, even more preferably 120° C. or lower, and even more preferably 100° C. or lower.
The content of the release agent in the toner particles is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 3% by mass or more, and is preferably 25% by mass or less, more preferably 21% by mass or less, even more preferably 17% by mass or less.

The toner particles may also contain additives such as charge control agents, magnetic powders, flowability improvers, conductivity adjusters, reinforcing fillers such as fibrous substances, antioxidants, anti-aging agents, and cleaning improvers.

[Physical Properties of Toner Particles]
The volume median particle diameter _D50 of the toner particles is, from the viewpoint of obtaining a printed coating film with good image quality and from the viewpoint of further improving the cleaning property of the toner, preferably 2 μm or more, more preferably 3 μm or more, even more preferably 4 μm or more, and is preferably 10 μm or less, more preferably 8 μm or less, even more preferably 7 μm or less.

The circularity of the toner particles is preferably 0.955 or more, more preferably 0.960 or more, from the viewpoint of obtaining a printed coating (image) of good quality, and is preferably 0.990 or less, more preferably 0.985 or less, and even more preferably 0.980 or less, from the viewpoint of cleaning properties.

The CV value of the toner particles is preferably 10% or more, more preferably 12% or more, and even more preferably 14% or more, from the viewpoint of improving the productivity of the toner, and is preferably 50% or less, more preferably 45% or less, and even more preferably 40% or less, from the viewpoint of obtaining good image quality.
The volume median particle diameter _D50 and CV value of the toner particles can be measured by the method described in the examples.

[Method of manufacturing toner for developing electrostatic images]
A method for producing a toner according to one embodiment of the present invention may be any known method such as a melt kneading method, an emulsion phase inversion method, a suspension polymerization method, or an emulsion aggregation method. The emulsion aggregation method and the melt kneading method are preferred, and the emulsion aggregation method is more preferred.

[Emulsification aggregation method]
The emulsion aggregation method includes a step of aggregating resin A or resin particles containing resin A and resin C in the same or different particles and a colorant in an aqueous medium, and a step of fusing the aggregated particles obtained in the step.
The aggregated particles obtained in the "step of aggregating in an aqueous medium" include aggregated particles 1 obtained by aggregating resin particles and a colorant in an aqueous medium, and aggregated particles 2 obtained by attaching shell resin particles containing an amorphous resin to the aggregated particles 1 as cores in an aqueous medium and aggregating the cores. In this specification, the term "aggregated particles" simply refers to aggregated particles 1 or 2.

<Step of aggregating resin particles>
In the step of aggregating the resin particles, resin particles containing resin A or resin A and resin C in the same or different particles and a colorant are aggregated in an aqueous medium to obtain aggregated particles 1. It is preferable to mix a resin particle dispersion containing resin particles with a colorant particle dispersion containing a colorant to aggregate these particles to obtain aggregated particles 1. Here, it is preferable to further aggregate the release agent in addition to the resin particles and the colorant, and it is more preferable to mix a resin particle dispersion, a colorant particle dispersion, and a release agent particle dispersion to aggregate these particles to obtain aggregated particles 1.

In the present invention, the aqueous medium used in the aqueous dispersion is a medium containing water as a main component, and the content of water in the aqueous medium is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, and 100% by mass or less. As the water, deionized water or distilled water is preferable.
Examples of components other than water that can form the aqueous medium together with water include organic solvents that dissolve in water, such as alkyl alcohols having 1 to 5 carbon atoms, dialkyl ketones having 3 to 5 carbon atoms, such as acetone and methyl ethyl ketone, and cyclic ethers, such as tetrahydrofuran. Among these, alkyl alcohols having 1 to 5 carbon atoms are preferred, and ethanol is more preferred.

(Method for producing resin particle dispersion)
The resin particles of resin A and the resin particles of resin C may be produced as a resin particle dispersion liquid containing resin A and resin C in the same or different particles.

Dispersion can be performed using a known method, but it is preferable to disperse by a phase inversion emulsification method. For example, the phase inversion emulsification method includes a method in which an aqueous medium is added to an organic solvent solution of a resin or a molten resin to perform phase inversion emulsification. A method in which an aqueous medium is added to an organic solvent solution of a resin to perform phase inversion emulsification is preferable.
The organic solvent used for phase inversion emulsification is not particularly limited as long as it dissolves the resin and is water-soluble, and examples thereof include methyl ethyl ketone.
A neutralizing agent may be added to the organic solvent solution. Examples of the neutralizing agent include basic substances. Examples of the basic substance include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; and nitrogen-containing basic substances such as ammonia, trimethylamine, and diethanolamine. Among these, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide are preferred.
The degree of neutralization of the resin constituting the resin particles is preferably 40 mol% or more, more preferably 50 mol% or more, even more preferably 60 mol% or more, even more preferably 70 mol% or more, and preferably 100 mol% or less, more preferably 95 mol% or less, even more preferably 90 mol% or less.
The degree of neutralization of the resin constituting the resin particles can be calculated by the following formula.
Degree of neutralization (mol %)=[{weight of neutralizing agent added (g)/equivalent weight of neutralizing agent}/[{weighted average acid value of resin constituting resin particles (mg KOH/g)×weight of resin constituting resin particles (g)}/(56×1000)]]×100

While stirring the organic solvent solution or the molten resin, the aqueous medium is gradually added to cause phase inversion.
From the viewpoint of improving the dispersion stability of the resin particles, the temperature of the organic solvent solution when the aqueous medium is added is preferably not less than the glass transition temperature of the resin A, for example, not less than 60° C., preferably not less than 70° C., and is preferably not more than 100° C., more preferably not more than 95° C., and even more preferably not more than 90° C.

After phase inversion emulsification, the organic solvent may be removed from the obtained dispersion by distillation or the like, if necessary. The resin particles may also be isolated by filtration or the like. It is preferable to use a resin particle dispersion obtained by removing the organic solvent from the dispersion obtained after phase inversion emulsification. In this case, the remaining amount of the organic solvent in the dispersion is preferably 1% by mass or less, more preferably 0.5% by mass or less, and even more preferably substantially 0% by mass.

The volume median particle size _D50 of the resin particles in the dispersion is preferably 0.08 μm or more, more preferably 0.12 μm or more, and preferably 1 μm or less, more preferably 0.5 μm or less, and even more preferably 0.3 μm or less.
The CV value of the resin particles in the dispersion is preferably 10% or more, more preferably 20% or more, and is preferably 40% or less, more preferably 35% or less.
The volume median particle diameter _D50 and CV value of the resin particles in the dispersion are measured by the method described in the examples.

From the viewpoint of improving the productivity of the toner and the dispersion stability of the resin particles, the solid content concentration of the resin particle dispersion is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and is preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 35% by mass or less.
The solid content is the total amount of non-volatile components.

(Method of producing colorant particle dispersion)
The colorant particle dispersion is preferably obtained by dispersing the pigment and an aqueous medium using a dispersing machine such as a homomixer, a homogenizer, an ultrasonic dispersing machine, etc. From the viewpoint of improving the dispersion stability of the pigment, the dispersion is preferably carried out in the presence of a polymer-type pigment dispersant (preferably the addition polymer E) or a surfactant.

The addition polymer E is an addition polymer of raw material monomers containing an aromatic group-containing monomer from the viewpoint of image density of the printed matter. That is, the addition polymer E contains a structural unit derived from an aromatic group-containing monomer in the main chain from the viewpoint of image density of the printed matter. The aromatic group-containing monomer is preferably a styrene-based compound a.
The raw material monomers for the addition polymer E preferably contain an addition polymerizable monomer b having an ionic group (hereinafter, also simply referred to as "monomer b") in addition to the styrene-based compound a.

Examples of the styrene-based compound a include substituted or unsubstituted styrene. Examples of the substituent substituted on the styrene include an alkyl group having 1 to 5 carbon atoms, a halogen atom, an alkoxy group having 1 to 5 carbon atoms, a sulfo group, or a salt thereof.
The molecular weight of the styrene-based compound a is preferably less than 1,000, more preferably 800 or less, and even more preferably 500 or less.
Examples of the styrene-based compound a include styrene, methylstyrene, α-methylstyrene, β-methylstyrene, tert-butylstyrene, chlorostyrene, chloromethylstyrene, methoxystyrene, styrenesulfonic acid, and salts thereof. Among these, styrene and α-methylstyrene are preferred.
The styrene-based compound a may be used alone or in combination of two or more kinds.
From the viewpoint of image density of the printed matter, the amount of the styrene-based compound a in the raw material monomers of the addition polymer E is preferably 30% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, and is 100% by mass or less, preferably 95% by mass or less, more preferably 90% by mass or less, even more preferably 85% by mass or less, and even more preferably 75% by mass or less.

The ionic group in the monomer b means a group that undergoes ionization in water.
Examples of the ionic group include a carboxy group, a sulfo group, a phosphate group, an amino group, or salts thereof.
The ionic group is preferably an anionic group from the viewpoint of improving the dispersion stability of the colorant particles. The anionic group is preferably an acidic group or a salt thereof, more preferably a carboxy group, a sulfo group or a salt thereof, and even more preferably a carboxy group or a salt thereof.
Examples of the addition polymerizable monomer having a carboxy group include (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, and 2-methacryloyloxymethylsuccinic acid.
Among these, an addition polymerizable monomer having an anionic group is preferred, (meth)acrylic acid is more preferred, and acrylic acid is even more preferred.
When monomer b is contained, the amount of monomer b in the raw material monomers of the addition polymer E is preferably 5 mass % or more, more preferably 10 mass % or more, even more preferably 15 mass % or more, even more preferably 25 mass % or more, and is preferably 50 mass % or less, more preferably 40 mass % or less.

In the present invention, the pigment dispersant is preferably a copolymer of styrene-based compound a and (meth)acrylic acid.

Furthermore, the raw material monomers for the addition polymer E may contain addition polymerizable monomers (other monomers) other than the monomers a and b.
Examples of the other monomers include addition polymerizable monomers having a polyalkylene oxide group, such as polyalkylene glycol (meth)acrylate and methoxypolyethylene glycol (meth)acrylate, styrene macromonomers having an addition polymerizable functional group at one end, alkyl (meth)acrylates having an alkyl group having 1 to 22 carbon atoms (preferably 6 to 18 carbon atoms), and aromatic group-containing (meth)acrylates. Examples of the aromatic group-containing (meth)acrylates include benzyl (meth)acrylate and phenoxyethyl (meth)acrylate.
When other monomers are contained, the amount of the other monomers in the raw material monomers of the addition polymer E is preferably 40 mass % or less, more preferably 30 mass % or less, even more preferably 20 mass % or less, even more preferably 10 mass % or less, and even more preferably 5 mass % or less.

From the viewpoint of further improving image density, the weight average molecular weight of the addition polymer E is preferably 3,000 or more, more preferably 5,000 or more, even more preferably 10,000 or more, and is preferably 100,000 or less, more preferably 50,000 or less, even more preferably 30,000 or less. The weight average molecular weight can be measured by the method described in the examples.

The addition polymer E can be produced, for example, by copolymerizing raw material monomers by a known polymerization method, preferably a solution polymerization method in which raw material monomers are polymerized by heating in a solvent together with a polymerization initiator, a polymerization chain transfer agent, and the like.
Examples of the polymerization initiator include peroxides such as dibutyl peroxide, persulfates such as sodium persulfate, and azo compounds such as 2,2'-azobis(2,4-dimethylvaleronitrile).
The amount of the polymerization initiator added is preferably 0.5 parts by mass or more and preferably 10 parts by mass or less based on 100 parts by mass of the raw material monomer.
Examples of the polymerization chain transfer agent include mercaptans such as 2-mercaptoethanol and 3-mercaptopropionic acid.
The amount of the polymerization chain transfer agent added is preferably 0.01 parts by mass or more and preferably 3 parts by mass or less based on 100 parts by mass of the raw material monomer.
After the polymerization reaction is completed, the produced polymer may be isolated and purified by a known method such as reprecipitation from the reaction solution or distillation of the solvent.

In the colorant particle dispersion, the mass ratio of the colorant to the addition polymer E (colorant/addition polymer E) is preferably 50/50 or more, more preferably 55/45 or more, even more preferably 60/40 or more, from the viewpoint of image density of the printed matter, and is preferably 95/5 or less, more preferably 90/10 or less, even more preferably 85/15 or less.

Examples of surfactants that improve the dispersion stability of the pigment include nonionic surfactants, anionic surfactants, and cationic surfactants. From the viewpoint of improving the dispersion stability of the pigment, nonionic surfactants are preferred. Examples of nonionic surfactants include polyoxyalkylene alkyl ethers, polyoxyalkylene alkenyl ethers, and polyoxyalkylene aryl ethers. Among these, polyoxyethylene aryl ethers are preferred, and polyoxyethylene distyrenated phenyl ether is more preferred.

In the colorant particle dispersion, the mass ratio of colorant to surfactant (colorant/surfactant) is preferably 50/50 or more, more preferably 55/45 or more, even more preferably 60/40 or more, even more preferably 65/35 or more, from the viewpoint of image density of the printed matter, and is preferably 95/5 or less, more preferably 90/10 or less, even more preferably 85/15 or less.

The content of the pigment in the colorant particle dispersion is preferably 5% by mass or more, more preferably 10% by mass or more, and is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less.
The solids concentration of the colorant particle dispersion is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and is preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less.

From the viewpoint of improving dispersibility in toner particles, the colorant particles have a volume median particle size _D50 of preferably 0.05 μm or more, more preferably 0.08 μm or more, even more preferably 0.1 μm or more, and preferably 0.4 μm or less, more preferably 0.3 μm or less, even more preferably 0.2 μm or less.
From the viewpoint of improving dispersibility in the toner particles, the CV value of the colorant particles is preferably 10% or more, more preferably 20% or more, and is preferably 40% or less, more preferably 35% or less, and even more preferably 30% or less.
The volume median particle diameter _D50 and CV value of the colorant particles are measured by the methods described in the Examples.

(Method for producing release agent particle dispersion)
The release agent particle dispersion liquid can be obtained, for example, by dispersing a dispersion liquid of the release agent and resin particles, and optionally an aqueous medium, at a temperature equal to or higher than the melting point of the release agent, using a dispersing machine such as a homogenizer, a high-pressure dispersing machine, or an ultrasonic dispersing machine.
The heating temperature during dispersion is preferably equal to or higher than the melting point of the release agent and equal to or higher than 80°C, more preferably equal to or higher than 85°C, even more preferably equal to or higher than 90°C, and is preferably equal to or lower than 100°C, more preferably equal to or lower than 98°C, even more preferably equal to or lower than 96°C.

The release agent particle dispersion can be obtained by using a surfactant, but is preferably obtained by mixing the release agent and resin particles. By preparing the release agent particles using the release agent and resin particles, the release agent particles are stabilized by the resin particles, and it becomes possible to disperse the release agent in an aqueous medium without using a surfactant. It is considered that the release agent particle dispersion has a structure in which a large number of resin particles are attached to the surface of the release agent particles.
The resin constituting the resin particles in which the release agent is dispersed is preferably a polyester resin, and it is more preferable to use the amorphous polyester resin A described above.

From the viewpoint of obtaining uniform aggregated particles 1 by aggregation, the release agent particles have a volume median particle size _D50 of preferably 0.05 μm or more, more preferably 0.1 μm or more, even more preferably 0.15 μm or more, and preferably 1 μm or less, more preferably 0.8 μm or less, even more preferably 0.5 μm or less.
The CV value of the release agent particles is preferably 10% or more, more preferably 20% or more, and preferably 50% or less.
The volume median particle diameter _D50 and CV value of the release agent particles are measured by the method described in the examples.

<Surfactants>
In the step of aggregating the resin particles, when the dispersions of the respective particles are mixed to prepare a mixed dispersion, the process may be performed in the presence of a surfactant from the viewpoint of improving the dispersion stability of the resin particles, the release agent particles, the colorant particles, etc. Examples of the surfactant include anionic surfactants such as alkylbenzene sulfonates and alkyl ether sulfates; and nonionic surfactants such as polyoxyethylene alkyl ethers and polyoxyethylene alkenyl ethers.
When a surfactant is used, the total amount used is preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, and even more preferably 0.5 parts by mass or more, relative to 100 parts by mass of the total amount of the binder resin in the aggregated particles 1, and is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 3 parts by mass or less.

<Flocculant>
In the step of aggregating the resin particles, it is preferable to add an aggregating agent from the viewpoint of efficient aggregation.
Examples of the flocculant include cationic surfactants such as quaternary salts, organic flocculants such as polyethyleneimine, and inorganic flocculants. Examples of the inorganic flocculant include inorganic metal salts such as sodium sulfate, sodium nitrate, sodium chloride, calcium chloride, and calcium nitrate; inorganic ammonium salts such as ammonium sulfate, ammonium chloride, and ammonium nitrate; and divalent or higher metal complexes.
From the viewpoint of improving the coagulation properties and obtaining uniformly aggregated particles 1, inorganic coagulants having a valence of 1 to 5 are preferred, inorganic metal salts having a valence of 1 to 2 and inorganic ammonium salts are more preferred, inorganic ammonium salts are even more preferred, and ammonium sulfate is even more preferred.

For example, 25 to 50 parts by mass of the aggregating agent is added to a mixed dispersion liquid containing resin particles, release agent particles, and colorant particles at 0°C or higher and 40°C or lower, relative to a total of 100 parts by mass of the binder resin in aggregated particle 1, and the resin particles, release agent particles, and colorant particles are aggregated in an aqueous medium to obtain aggregated particle 1. Furthermore, from the viewpoint of promoting aggregation, it is preferable to increase the temperature of the dispersion liquid after adding the aggregating agent.

Methods for stopping the aggregation include cooling the dispersion, adding an aggregation terminator, diluting the dispersion, and the like. From the viewpoint of reliably preventing unnecessary aggregation, the method of stopping the aggregation by adding an aggregation terminator is preferred.

<Aggregation stopper>
The aggregation terminator is preferably a surfactant, more preferably an anionic surfactant. Examples of the anionic surfactant include alkylbenzenesulfonate, alkyl sulfate, alkyl ether sulfate, polyoxyalkylene alkyl ether sulfate, arylsulfonate, and arylsulfonic acid formalin condensate, and are preferably an alkali metal salt of arylsulfonic acid formalin condensate, and more preferably a sodium salt of β-naphthalenesulfonic acid formalin condensate. These may be used alone or in combination of two or more. The aggregation terminator may be added in the form of an aqueous solution.
The amount of the aggregation terminator added is preferably 10 parts by mass or more, and more preferably 15 parts by mass or more, relative to 100 parts by mass of the total of the binder resins in the aggregated particles 1, from the viewpoint of reliably preventing unnecessary aggregation, and is preferably 45 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 35 parts by mass or less, from the viewpoint of reducing residue in the toner.

The volume median particle diameter D ₅₀ of the aggregated particles 1 is preferably 2 μm or more, more preferably 3 μm or more, even more preferably 4 μm or more, and is preferably 10 μm or less, more preferably 8 μm or less, even more preferably 7 μm or less.

In the present invention, after the step of aggregating the resin particles and before the step of fusing, a step of adhering shell resin particles containing an amorphous resin to the obtained aggregated particles 1 and aggregating them to obtain aggregated particles 2 may be included. By including the step of aggregating the shell resin particles, toner particles having a core-shell structure can be obtained.
The shell resin particles are preferably made of a non-crystalline resin, more preferably made of a non-crystalline polyester resin, and further preferably made of at least one type selected from the above-mentioned resin A and resin B.
The shell resin particle dispersion liquid can be obtained by the same method as the above-mentioned method for producing the resin particle dispersion liquid.
Furthermore, when the toner manufacturing method includes a step of aggregating shell resin particles, it is preferable to stop the aggregation in the step when the aggregated particles 2 have grown to an appropriate particle size as toner particles, and a method of stopping the aggregation by adding the above-mentioned aggregation terminator is preferable.
The mass ratio of the shell resin particles to the mass of the aggregated particles 1 [shell resin particles/aggregated particles 1] is, from the viewpoint of low-temperature fixing property of the toner, preferably 1/99 or more, more preferably 3/97 or more, even more preferably 5/95 or more, and is preferably 25/75 or less, more preferably 20/80 or less, even more preferably 15/85 or less.

<Fusing step>
In the fusion step, for example, the aggregated particles are fused in an aqueous medium.
By fusion, the particles contained in the aggregated particles are fused together to obtain fused particles.
In the fusion step, from the viewpoint of improving the fusion properties of the aggregated particles and from the viewpoint of improving the low-temperature fixing properties of the toner, the aggregated particles are maintained at a temperature equal to or higher than the glass transition temperature of the resin having the highest glass transition temperature among the amorphous polyester resins contained in the aggregated particles.
In the fusion step, an aggregation terminator can be used as a dispersant.
From the viewpoint of improving the fusibility of the aggregated particles and improving the productivity of the toner, the holding temperature when fusing the aggregated particles is preferably at least 2° C. higher, more preferably at least 3° C. higher, and even more preferably at least 5° C. higher than the glass transition temperature of the resin having the highest glass transition temperature among the amorphous polyester resins, and is preferably not more than 30° C. higher, more preferably not more than 25° C. higher, and even more preferably not more than 20° C. higher than the glass transition temperature of the resin having the highest glass transition temperature among the amorphous polyester resins.
In this case, the time for which the toner is maintained at a temperature equal to or higher than the glass transition temperature of the amorphous polyester resin is, from the viewpoint of improving the low-temperature fixing property of the toner, preferably 1 minute or more, more preferably 10 minutes or more, even more preferably 30 minutes or more, and is preferably 240 minutes or less, more preferably 180 minutes or less, even more preferably 120 minutes or less, even more preferably 90 minutes or less.
It is preferable to maintain the temperature at the above temperature until the desired circularity is achieved.

The volume median particle size _D50 of the fused particles obtained by fusion is preferably 2 μm or more, more preferably 3 μm or more, even more preferably 4 μm or more, and is preferably 10 μm or less, more preferably 8 μm or less, even more preferably 7 μm or less.

The circularity of the fused particles obtained by fusion is preferably 0.955 or more, more preferably 0.960 or more, and is preferably 0.990 or less, more preferably 0.985 or less, and further preferably 0.980 or less.
The fusion is preferably terminated after the above-mentioned preferred circularity is reached.
The circularity is measured by the method described in the Examples.

<Post-treatment process>
After the fusion step, a post-treatment step may be performed, and the fused particles are isolated to obtain toner particles. Since the fused particles obtained in the fusion step are present in an aqueous medium, it is preferable to first perform solid-liquid separation. For the solid-liquid separation, a suction filtration method or the like is preferably used.
It is preferable to wash the solid-liquid separation product. In this case, it is preferable to remove the surfactant added, and therefore it is preferable to wash the product with an aqueous medium at a temperature below the cloud point of the surfactant. It is preferable to wash the product several times.
Next, drying is preferably performed. Examples of the drying method include vacuum low-temperature drying, vibration-type fluidized bed drying, spray drying, freeze drying, and flash jet drying.

[Melt kneading method]
In the present invention, the melt-kneading method involves, for example, uniformly mixing a binder resin, a colorant, and, if necessary, additives such as a release agent in a mixer such as a Henschel mixer, and then melt-kneading the mixture in an internal kneader, a single-screw or twin-screw extruder, an open roll type kneader, etc. The mixture is then cooled, pulverized, and classified to produce toner particles.

The obtained toner particles can be used as is as the toner of the present invention. It is also preferable to add an external additive to the surface of the toner particles before using the toner of the present invention.

<External Additives>
Examples of the external additive include inorganic fine particles such as hydrophobic silica, titanium oxide, alumina, cerium oxide, and carbon black, and polymer fine particles such as polycarbonate, polymethyl methacrylate, and silicone resin. Among these, hydrophobic silica is preferred. The external additive may be used alone or in combination of two or more. Two or more types of hydrophobic silica having different particle sizes may also be used.
When the surface treatment of the toner particles is performed using an external additive, the amount of the external additive added is preferably 1 part by mass or more, more preferably 2 parts by mass or more, even more preferably 3 parts by mass or more, and is preferably 5 parts by mass or less, more preferably 4.5 parts by mass or less, and even more preferably 4 parts by mass or less, relative to 100 parts by mass of the toner particles.

Toner is used to develop electrostatic images in electrophotographic printing. Toner can be used, for example, as a one-component developer or mixed with a carrier to form a two-component developer.

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Each property value was measured and evaluated by the following methods.
In the notation "alkylene oxide (X)", the number X in parentheses means the average number of moles of alkylene oxide added.

[Measurement method]
[Acid value of resin]
The acid value of the resin was measured according to the neutralization titration method described in JIS K 0070:1992, except that the measurement solvent was chloroform.

[Softening point, crystallinity index, melting point and glass transition temperature of resin]
(1) Softening point Using a flow tester "CFT-500D" (manufactured by Shimadzu Corporation), 1 g of a sample was extruded from a nozzle having a diameter of 1 mm and a length of 1 mm under a load of 1.96 MPa applied by a plunger while heating the sample at a temperature increase rate of 6°C/min. The plunger descent amount of the flow tester was plotted against the temperature, and the temperature at which half of the sample flowed out was taken as the softening point.
(2) Crystallinity Index Using a differential scanning calorimeter "Q100" (manufactured by TA Instruments Japan Co., Ltd.), 0.02 g of a sample was weighed into an aluminum pan and cooled to 0°C at a temperature drop rate of 10°C/min. The sample was then left to stand for 1 minute, and then heated to 180°C at a temperature increase rate of 10°C/min to measure the amount of heat. The temperature of the peak with the largest peak area among the observed endothermic peaks was defined as the endothermic maximum peak temperature (1), and the crystallinity index was calculated by (softening point (°C))/(endothermic maximum peak temperature (1) (°C)).
(3) Melting point and glass transition temperature Using a differential scanning calorimeter "Q100" (manufactured by TA Instruments Japan Co., Ltd.), 0.02 g of a sample was weighed into an aluminum pan, heated to 200°C, and cooled from that temperature to 0°C at a rate of 10°C/min. The sample was then heated at a rate of 10°C/min, and the amount of heat was measured. Among the endothermic peaks observed, the temperature of the peak with the largest peak area was taken as the maximum endothermic peak temperature (2). In the case of a crystalline resin, this peak temperature was taken as the melting point.
In the case of an amorphous resin, when a peak was observed, the temperature of the peak was taken as the glass transition temperature. When no peak was observed but a step was observed, the temperature at the intersection of the tangent showing the maximum slope of the curve at the step and an extension of the baseline on the low temperature side of the step was taken as the glass transition temperature.

[Weight average molecular weight of pigment dispersant (addition polymer E)]
The measurement was performed by gel permeation chromatography (GPC apparatus (HLC-8320GPC) manufactured by Tosoh Corporation, columns (TSKgel SuperAWM-H, TSKgel SuperAW3000, TSKgel guardcolumn Super AW-H), flow rate: 0.5 mL/min) using a solution of phosphoric acid and lithium bromide dissolved in N,N-dimethylformamide to concentrations of 43 mmol/L and 50 mmol/L, respectively, as an eluent, and using a monodisperse polystyrene kit with known molecular weight (PStQuick B (F-550, F-80, F-10, F-1, A-1000), PStQuick C (F-288, F-40, F-4, A-5000, A-500), manufactured by Tosoh Corporation) as a standard substance.
The measurement sample was prepared by mixing 0.1 g of addition polymer E with 10 mL of the eluent in a glass vial, stirring the mixture with a magnetic stirrer at 25° C. for 10 hours, and filtering the mixture with a syringe filter (DISMIC-13HP PTFE 0.2 μm, manufactured by Advantec Co., Ltd.).

[Acid value of pigment dispersant (addition polymer E)]
Addition polymer E was dissolved in a titration solvent of toluene and acetone (2:1) in an automatic potentiometric titrator (Kyoto Electronics Manufacturing Co., Ltd., electric burette, model number: APB-610), and titrated with 0.1 N potassium hydroxide/ethanol solution by potentiometric titration, with the inflection point on the titration curve being the end point. The acid value was calculated from the titration amount of the potassium hydroxide solution up to the end point.

[Melting point of release agent]
Using a differential scanning calorimeter "Q100" (manufactured by TA Instruments Japan Co., Ltd.), 0.02 g of a sample was weighed into an aluminum pan, heated to 200°C, and cooled from that temperature at a rate of 10°C/min to 0°C. The sample was then heated at a rate of 10°C/min, the amount of heat was measured, and the maximum endothermic peak temperature was taken as the melting point.

[Volume Median Particle Size _D50 and CV Value of Resin Particles, Release Agent Particles, and Colorant Particles]
(1) Measuring device: Laser diffraction type particle size measuring instrument "LA-920" (manufactured by Horiba, Ltd.)
(2) Measurement conditions: Distilled water was added to the measurement cell, and the volume median particle size _D50 and the volume average particle size _DV were measured at a concentration that brought the absorbance into an appropriate range. The CV value (particle size distribution) was calculated according to the following formula.
CV value (%) = (standard deviation of particle size distribution / volume average particle size D _V ) × 100

[Solid Content Concentration of Resin Particle Dispersion, Release Agent Particle Dispersion, and Colorant Particle Dispersion]
Using an infrared moisture meter "FD-230" (Kett Electric Laboratory Co., Ltd.), the moisture (mass%) of 5 g of the measurement sample was measured at a drying temperature of 150°C and measurement mode 96 (monitoring time 2.5 min/fluctuation range 0.05%). The solid content concentration was calculated according to the following formula.
Solid content concentration (mass%) = 100-moisture (mass%)

[Volume Median Particle Diameter _D50 of Agglomerated Particles]
・Measuring instrument: "Coulter Multisizer (registered trademark) III" (manufactured by Beckman Coulter, Inc.)
Aperture diameter: 50 μm
Analysis software: "Multisizer (registered trademark) III version 3.51" (Beckman Coulter, Inc.)
・Electrolyte: "Isoton (registered trademark) II" (Beckman Coulter, Inc.)
Measurement conditions: The sample dispersion was added to 100 mL of the electrolyte to adjust the concentration to a level that would allow the particle sizes of 30,000 particles to be measured in 20 seconds, and the 30,000 particles were then measured and the volume median particle size _D50 was determined from the particle size distribution.

[Circularity of fused particles]
The circularity of the fused particles was measured under the following conditions.
・Measuring device: Flow type particle image analyzer "FPIA-3000" (manufactured by Sysmex Corporation)
Preparation of dispersion: A dispersion of fused particles was prepared by diluting with deionized water so that the solid content concentration was 0.001 to 0.05% by mass.
Measurement mode: HPF measurement mode

[Volume Median Particle Size _D50 and CV Value of Toner Particles]
The measuring device, aperture diameter, analysis software, and electrolyte used were the same as those used in the measurement of the volume median particle diameter D ₅₀ of the agglomerated particles.
Dispersion: Polyoxyethylene lauryl ether "EMULGEN (registered trademark) 109P" (manufactured by Kao Corporation, HLB (hydrophile-lipophile balance): 13.6) was dissolved in the electrolyte to obtain a dispersion having a concentration of 5% by mass.
Dispersion conditions: 10 mg of a toner measurement sample was added to 5 mL of the dispersion liquid, and dispersed for 1 minute using an ultrasonic disperser. Thereafter, 25 mL of electrolyte was added, and the mixture was further dispersed for 1 minute using an ultrasonic disperser to prepare a sample dispersion liquid.
Measurement conditions: The sample dispersion was added to 100 mL of the electrolyte to adjust the concentration to a level that would allow the particle sizes of 30,000 particles to be measured in 20 seconds. The 30,000 particles were then measured, and the volume median particle size _D50 and volume average particle size _DV were determined from the particle size distribution.
The CV value (%) was calculated according to the following formula.
CV value (%) = (standard deviation of particle size distribution / volume average particle size D _V ) × 100
[Ester group concentration]
Calculated using the above formula.

[Production of resin]
[Production of amorphous polyester resin]
Production Example A1 (Production of Resin A-1)
Neopentyl glycol, terephthalic acid, and an esterification catalyst (tin(II) di(2-ethylhexanoate)) shown in Table 1 were placed in a 10 L four-neck flask equipped with a thermometer, a stainless steel stirring rod, a dehydration tube, a cooling tube, and a nitrogen inlet tube, and the mixture was heated to 180°C in a mantle heater in a nitrogen atmosphere, reacted for 2 hours, and then heated stepwise to 210°C at a rate of 5°C/h. After cooling to 180°C, isophthalic acid shown in Table 1 was added, the mixture was heated again to 190°C, reacted for 1 hour, and then heated stepwise to 220°C at a rate of 10°C/h. The mixture was then reacted at 13.3 kPa to the softening point shown in Table 1 to obtain Resin A-1. The physical properties of Resin A-1 are shown in Table 1.

Production Example A2 (Production of Resin A-2)
The raw material monomers of polyester resin other than isophthalic acid shown in Table 1, and the esterification catalyst were placed in a 10 L four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple. Under a nitrogen atmosphere, the reaction system was held at 205 ° C. for 1 hour, then heated from 205 ° C. to 235 ° C. at 10 ° C./h, and then held at 235 ° C. for 3 hours to perform polycondensation. After that, it was cooled to 185 ° C., and isophthalic acid was added to the reaction system, heated from 185 ° C. to 235 ° C. at 10 ° C./h, and reacted at 235 ° C. for 5 hours, and reacted at 235 ° C. and 10 kPa until the softening point shown in Table 1 was obtained. The physical properties of resin A-2 are shown in Table 1.

Production Example A3 (Production of Resin A-3)
The raw material monomers, esterification catalyst and gallic acid of the polyester resin shown in Table 1 were placed in a 10 L four-neck flask equipped with a nitrogen inlet tube, a dehydration tube equipped with a fractionating tube through which hot water of 98°C was passed, a stirrer and a thermocouple, and the mixture was kept at 180°C for 1 hour under a nitrogen atmosphere, and then heated from 180°C to 230°C at a rate of 10°C/h, and then polycondensed at 230°C for 5 hours. The reaction was further carried out at 230°C under a reduced pressure of 10 kPa until the softening point shown in Table 1 was reached, to obtain Resin A-3. The physical properties of Resin A-3 are shown in Table 1.

Production Example B1 (Production of Resin B-1)
The alcohol component, terephthalic acid and esterification catalyst shown in Table 1 were placed in a 10 L four-neck flask equipped with a thermometer, a stainless steel stirring rod, a downflow condenser with a dehydration tube and a nitrogen inlet tube. Under a nitrogen atmosphere, the reaction system was heated to 235 ° C. while stirring, and after maintaining for 4 hours, the pressure in the flask was further reduced and maintained at 8.0 kPa for 1 hour. Thereafter, the mixture was cooled to 210 ° C. and returned to atmospheric pressure, and then fumaric acid, trimellitic anhydride and 4-tert-butylcatechol shown in Table 1 were added, and the mixture was maintained at a temperature of 210 ° C. for 3 hours, after which the pressure in the flask was further reduced and the mixture was reacted at 8.0 kPa until the softening point reached the temperature shown in Table 1 to obtain resin B-1. The physical properties of the obtained resin B-1 are shown in Table 1.

[Production of Crystalline Polyester Resin C]
Production Example C1 (Production of Resin C-1)
The raw material monomers of the polyester resin shown in Table 2 were placed in a 10 L four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple. Under a nitrogen atmosphere, the reaction system was heated to 135°C while stirring, and then held at 135°C for 3 hours, and then heated from 135°C to 200°C over 10 hours. Thereafter, tin(II) di(2-ethylhexanoate) shown in Table 2 was added, and the mixture was further held at 200°C for 1 hour, after which the pressure in the flask was reduced and the mixture was held under a reduced pressure of 8 kPa until the softening point reached the temperature shown in Table 2, to obtain Resin C-1, a crystalline polyester resin. The physical properties of Resin C-1 are shown in Table 2.

[Production of Pigment Dispersant (Addition Polymer E)]
A monomer mixture was prepared by mixing 61.6 parts by mass of acrylic acid, 128.8 parts by mass of styrene, and 9.6 parts by mass of α-methylstyrene. 20 parts by mass of methyl ethyl ketone, 0.3 parts by mass of the polymerization chain transfer agent 2-mercaptoethanol, and 10% by mass of the monomer mixture were placed in a reaction vessel and mixed, followed by thorough nitrogen gas replacement. Meanwhile, a mixed solution of the remaining 90% by mass of the monomer mixed solution, 0.27 parts by mass of the polymerization chain transfer agent, 60 parts by mass of methyl ethyl ketone, and 2.2 parts by mass of an azo-based radical polymerization initiator (2,2'-azobis(2,4-dimethylvaleronitrile) was placed in a dropping funnel, and the monomer mixed solution in the reaction vessel was heated to 65°C under a nitrogen atmosphere while being stirred, and the mixed solution in the dropping funnel was dropped over 3 hours. After 2 hours had elapsed at 65°C from the end of the dropping, a solution in which 0.3 parts by mass of the polymerization initiator was dissolved in 5 parts by mass of methyl ethyl ketone was added, and the mixture was further aged at 65°C for 2 hours and at 70°C for 2 hours, thereby obtaining a methyl ethyl ketone solution of an addition polymer E having a carboxy group (weight average molecular weight: 20,100). Thereafter, the mixture was dried under reduced pressure to obtain an addition polymer E (acid value 240 mgKOH/g).

[Production of Resin Particle Dispersion]
Production Example X1 (Production of Resin Particle Dispersion X-1)
800 g of Resin A-1, 200 g of Resin C-1, and 1000 g of methyl ethyl ketone were placed in a 5 L vessel equipped with a stirrer, a reflux condenser, a dropping funnel, a thermometer, and a nitrogen inlet tube, and the resins were dissolved over 1 hour at 80° C. A 5% by mass aqueous solution of sodium hydroxide was added to the resulting solution so that the degree of neutralization with respect to the acid value of the resin was 80 mol%, and the mixture was stirred for 30 minutes.
Next, while maintaining the temperature at 80° C., 3000 g of deionized water was added over 60 minutes while stirring at 280 r/min (circumferential speed 88 m/min) to cause phase inversion emulsification. While continuing to maintain the temperature at 80° C., methyl ethyl ketone was distilled off under reduced pressure to obtain an aqueous dispersion. Thereafter, the aqueous dispersion was cooled to 30° C. while stirring at 280 r/min (circumferential speed 88 m/min), and deionized water was added so that the solid content concentration became 25% by mass, thereby obtaining a resin particle dispersion X-1. The volume median particle diameter D ₅₀ and CV value of the obtained resin particles are shown in Table 3.

Production Examples X2 to X4 (Production of Resin Particle Dispersions X-2 to X-4)
Resin particle dispersions X-2 to X-4 were obtained in the same manner as in Production Example X1, except that Resin A-1 was changed to Resin A-2, A-3, or B-1. The volume median particle diameter _D50 and CV value of the obtained resin particles are shown in Table 3.

Production Example P1 (Production of Resin Particle Dispersion P-1)
200 g of resin A-1 and 200 g of methyl ethyl ketone were placed in a 3 L container equipped with a stirrer, reflux condenser, dropping funnel, thermometer and nitrogen inlet tube, and resin A-1 was dissolved at 80 ° C. for 1 hour. A 5% by mass aqueous solution of sodium hydroxide was added to the obtained solution so that the degree of neutralization was 75 mol% with respect to the acid value of resin A-1, and stirred for 30 minutes. Next, while maintaining the temperature at 80 ° C., 600 g of deionized water was added over 50 minutes while stirring at 280 r / min (circumferential speed 88 m / min), and phase inversion emulsification was performed. While continuing to maintain the temperature at 80 ° C., methyl ethyl ketone was distilled off under reduced pressure to obtain an aqueous dispersion. Thereafter, the aqueous dispersion was cooled to 30 ° C. while stirring at 280 r / min (circumferential speed 88 m / min), and deionized water was added so that the solid content concentration was 25 mass%, to obtain a resin particle dispersion P-1. The volume median particle diameter _D50 and CV value of the obtained resin particles are shown in Table 3.

[Preparation of release agent particle dispersion]
Production Example W1 (Production of Release Agent Particle Dispersion W-1)
In a beaker having an internal volume of 1 L, 30 g of deionized water, 100 g of resin particle dispersion P-1, and 50 g of paraffin wax "HNP-9" (manufactured by Nippon Seiro Co., Ltd., melting point 75°C) were added, and the temperature was maintained at 90 to 95°C to melt and stir to obtain a molten mixture. The obtained molten mixture was further dispersed for 20 minutes using an ultrasonic homogenizer "US-600T" (manufactured by Nippon Seiki Seisakusho Co., Ltd.) while maintaining the temperature at 90 to 95°C, and then cooled to room temperature (20°C). Deionized water was added to adjust the solid content concentration to 40 mass%, and a release agent particle dispersion W-1 was obtained. The volume median particle diameter _D50 of the release agent particles in the release agent particle dispersion was 0.29 μm, and the CV value was 37%.

Production Example W2 (Production of Release Agent Particle Dispersion W-2)
A release agent particle dispersion W-2 was obtained in the same manner as in Production Example W1, except that the type of release agent used was changed to Fischer-Tropsch wax "FNP-0090" (manufactured by Nippon Seiro Co., Ltd., melting point 90°C). The volume median particle diameter _D50 of the release agent particles in the release agent particle dispersion was 0.26 μm, and the CV value was 39%.

[Preparation of Colorant Particle Dispersion]
Production Example E1 (Production of Colorant Particle Dispersion E-1)
In a 2L container, 150g of C.I. Pigment Red 254 ("PV Fast Red D3G", manufactured by Clariant Chemicals Co., Ltd.), 50g of nonionic surfactant (polyoxyethylene distyrenated phenyl ether) "Emulgen A-60", and 750g of deionized water were added, and the mixture was stirred at 6400 rpm/min at 20°C for 1 hour using a stirrer "Labo-lution" (manufactured by Primix Corporation) equipped with a dispersing blade. The mixture was then passed through a 200-mesh filter and treated with a homogenizer "Microfluidizer M-110EH" (manufactured by Microfluidics Co., Ltd.) at a pressure of 150 MPa for 15 passes. The mixture was then passed through a 200-mesh filter and deionized water was added so that the solid content concentration was 20% by mass, thereby obtaining a colorant particle dispersion E-1. The volume median particle diameter _D50 and CV value of the obtained colorant particles are shown in Table 4.

Production Example E2 (Production of Colorant Particle Dispersion E-2)
50 g of addition polymer E and 108 g of methyl ethyl ketone were placed in a 2 L container, and the addition polymer E was dissolved at 20 ° C. To the resulting solution, 30 g of 5 mol / L sodium hydroxide aqueous solution (an amount that results in a neutralization degree of 60 mol% relative to the acid value of the addition polymer E) was added, and 516 g of deionized water was further added, and the mixture was stirred with a disper blade at 2000 r / min at 20 ° C. for 10 minutes. Next, 150 g of C.I. Pigment Red 254 ("PV Fast Red D3G", Clariant Chemicals Co., Ltd.) was added, and the mixture was stirred with a disper blade at 6400 r / min at 10 ° C. for 1 hour. Thereafter, the mixture was passed through a 200 mesh filter and treated five times at a pressure of 150 MPa using a homogenizer "Microfluidizer M-110EH" (Microfluidics). The resulting dispersion was stirred at reduced pressure at 70° C. to remove methyl ethyl ketone and a portion of the water. After cooling, the mixture was passed through a 200 mesh filter, and deionized water was added to give a solids concentration of 20% by mass to obtain colorant particle dispersion E-2. The volume median particle diameter _D50 and CV value of the colorant particles in the resulting colorant particle dispersion E-2 are shown in Table 4.

Production Examples E3 and E4 (Production of Colorant Particle Dispersions E-3 and E-4)
Colorant particle dispersions E-3 and E-4 were obtained in the same manner as in Production Example E1, except that the pigment used was changed to C.I. Pigment Red 269 ("Permanent Carmine 3810", manufactured by Sanyo Color Co., Ltd.) or C.I. Pigment Red 57:1 ("NO. 7510 CARMINE 6B", manufactured by Daido Chemical Industry Co., Ltd.). The volume median particle diameter _D50 and CV value of the obtained colorant particles are shown in Table 4.

[Production of Toner 1]
Example 1 (Production of Toner 1)
Into a 3 L four-neck flask equipped with a dehydrating tube, a stirrer, and a thermocouple, 450 g of resin particle dispersion X-1, 31 g of release agent particle dispersion W-1, 31 g of release agent particle dispersion W-2, 61 g of colorant particle dispersion E-1, and 93 g of deionized water were charged and mixed at a temperature of 25° C. Next, while stirring the resulting mixture, a solution obtained by dissolving 42 g of ammonium sulfate in 1213 g of deionized water and adding a 4.8 mass % potassium hydroxide aqueous solution to adjust the pH to 8.0 was dropped at 25° C. over 30 minutes, and then the temperature was raised to 55° C. over 1 hour and maintained at 55° C. until the volume median particle diameter D ₅₀ of the aggregated particles reached 6.0 μm, thereby obtaining a dispersion of aggregated particles 1.
To the obtained dispersion liquid of aggregated particles 1, 208 g of a 20 mass % aqueous solution of "Demol N" (sodium salt of β-naphthalenesulfonic acid formalin condensate, manufactured by Kao Corporation), 477 g of deionized water, and 383 g of a 4.8 mass % aqueous solution of potassium hydroxide were added. Thereafter, the temperature was raised to 70° C. over one hour, and the temperature was maintained at 70° C. until the circularity reached 0.970, thereby obtaining a dispersion liquid of fused particles in which aggregated particles 1 were fused.
The obtained dispersion of fused particles was cooled to 30° C., and the dispersion was subjected to suction filtration to separate the solid content, and then washed with deionized water at 25° C. and suction filtration was performed for 2 hours at 25° C. Thereafter, the solid content was vacuum dried at 33° C. for 24 hours using a vacuum constant temperature dryer “DRV622DA” (manufactured by ADVANTEC CORPORATION) to obtain toner particles 1.
100 parts by mass of toner particles, 2.5 parts by mass of hydrophobic silica "RY50" (manufactured by Nippon Aerosil Co., Ltd., number average particle size: 0.04 μm), and 1.0 part by mass of hydrophobic silica "Cabosil (registered trademark) TS720" (manufactured by Cabot Japan Co., Ltd., number average particle size: 0.012 μm) were placed in a Henschel mixer, stirred, and passed through a 150 mesh sieve to obtain toner 1. The obtained toner 1 was evaluated by the following evaluation method. The physical property values of toner particles 1 and the evaluation results of toner 1 are shown in Table 5.

[Evaluation method]
[Image density of printed matter]
A solid image with a toner adhesion of 0.25 mg/cm ² on high-quality paper “J paper A4 size” (manufactured by Fuji Xerox Co., Ltd.) was printed without fixing using a commercially available printer “Microline 5400” (manufactured by OKI Data Corporation).
Next, the same printer was prepared with a temperature-variable fixing unit, the temperature of the fixing unit was set to 130° C., and the toner was fixed at a speed of 1.7 seconds per sheet in the A4 portrait direction to obtain a printout.
Thirty sheets of high-quality paper "Excellent White Paper A4 size" (manufactured by Oki Data Corporation) were placed under the print, and the reflected image density of the solid image portion of the output print was measured using a colorimeter "SpectroEye" (manufactured by GretagMacbeth, light irradiation conditions: standard light source D50, observation field of view 2°, density standard DINNB, absolute white standard), and the values measured at any 10 points on the image were averaged to obtain the image density. The higher the value, the better the image density.

Examples 2 to 4 and Comparative Examples 1 to 3 (Production of Toners 2 to 4, 11 to 13)
Except for changing the type of resin particle dispersion liquid and the type of colorant particle dispersion liquid used as shown in Table 5, toner particles 2 to 4, 11 to 13 and toners 2 to 4, 11 to 13 were obtained in the same manner as in Example 1 and evaluated in the same manner as in Toner 1. The physical property values of the obtained toner particles 2 to 4, 11 to 13 and the evaluation results of toners 2 to 4, 11 to 13 are shown in Table 5.

Example 5 (Production of Toner 5)
As shown in Table 6, 80 parts by mass of amorphous polyester resin A-1 and 20 parts by mass of crystalline polyester resin C-1, 8 parts by mass of C.I. Pigment Red 254 ("PV Fast Red D3G", manufactured by Clariant Chemicals Co., Ltd.), and 2 parts by mass of paraffin wax "HNP-9" (manufactured by Nippon Seiro Co., Ltd., melting point 75 ° C.) as a release agent, and 2 parts by mass of Fischer-Tropsch wax "FNP-0090" (manufactured by Nippon Seiro Co., Ltd., melting point 90 ° C.) were mixed in a Henschel mixer and melt-kneaded under the conditions shown below. The obtained mixture was melt-kneaded at a screw rotation speed of 200 r / min and a barrel set temperature of 100 ° C. using a co-rotating twin-screw extruder with a kneading part total length of 1560 mm, a screw diameter of 42 mm, and a barrel inner diameter of 43 mm, to obtain a melt-kneaded product. The feed rate of the mixture was 20 kg / hour, and the average residence time was about 18 seconds. The resulting molten kneaded product was cooled, coarsely pulverized, pulverized in a jet mill, and classified using an air classifier (manufactured by Nippon Pneumatic Mfg. Co., Ltd.) to obtain powder (toner particles 5) having a volume median particle size (D ₅₀ ) of 6.0 μm.
100 parts by mass of toner particles 5, 2.5 parts by mass of hydrophobic silica "RY50" (manufactured by Nippon Aerosil Co., Ltd., number average particle size; 0.04 μm), and 1.0 part by mass of hydrophobic silica "Cabosil (registered trademark) TS720" (manufactured by Cabot Japan Co., Ltd., number average particle size; 0.012 μm) were placed in a Henschel mixer, stirred, and passed through a 150 mesh sieve to obtain toner 5, which was evaluated in the same manner as toner 1. The physical property values of toner particles 5 and the evaluation results of toner 5 are shown in Table 6.

From Tables 5 and 6, it can be seen that the printed matter obtained using the toner of the present invention containing the amorphous polyester resin A having an ester group concentration of 5.0 mmol/g or more and 12.0 mmol/g or less and C.I. Pigment Red 254 has excellent image density (Examples 1 to 5).
In contrast, the printed matter obtained using a toner containing an amorphous polyester resin A having an ester group concentration of 5.0 mmol/g or more and 12.0 mmol/g or less and containing C.I. Pigment Red 269 or C.I. Pigment Red 57:1 as a colorant had a low image density (Comparative Examples 1 and 2). Also, the printed matter obtained using a toner containing C.I. Pigment Red 254 as a colorant and containing an amorphous polyester resin having an ester group concentration of less than 5.0 mmol/g had a low image density (Comparative Example 3).

Claims (5)

A toner for developing electrostatic images, comprising a binder resin and a colorant,
the binder resin contains an amorphous polyester resin A having an ester group concentration of 5.0 mmol/g or more and 12.0 mmol/g or less,
The colorant is C.I. Pigment Red 254;
Toner for developing electrostatic images. The toner for developing electrostatic images according to claim 1, wherein the binder resin further contains crystalline polyester resin C. The toner for developing electrostatic images according to claim 1 or 2, further comprising a pigment dispersant. The toner for developing electrostatic images according to claim 3, wherein the pigment dispersant contains an addition polymer E that contains a structural unit derived from an aromatic group-containing monomer. A method for producing the toner for developing electrostatic images according to any one of claims 1 to 4, comprising the steps of aggregating resin particles and colorant particles, and fusing the aggregated particles obtained in said step,
the resin particles contain an amorphous polyester resin A having an ester group concentration of 5.0 mmol/g or more and 12.0 mmol/g or less,
The colorant contained in the colorant particles is C.I. Pigment Red 254.