Toner for electrostatic charge image development

Abstract

To provide an electrostatic charge image development toner that causes less covering and can maintain a high stability of the concentration of an image even in a continuous printing with less toner consumption.SOLUTION: In an electrostatic charge image development toner, small-diameter silica particles with particles of 10 nm to 30 nm, both inclusive, converted from a specific surface area and large-diameter silica particles with particles of 70 nm to 190 nm, both inclusive, converted from a specific surface area are added to toner mother particles with a circularity of at least 0.965, and the mass ratio of the amount of the added large-particle silica particles to the added small-particle silica particles is in the range of 7 to 18, both inclusive.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to a toner for developing electrostatic images. [Background technology]

[0002] Image forming devices such as electrophotographers, electrostatic recording devices, and electrostatic printing devices widely employ a technique that forms a desired image by developing an electrostatic latent image formed on a photoreceptor with electrostatic image developing toner. Such techniques are applied to photocopiers, printers, facsimile machines, and their combined devices. In recent years, with the increasing demand for higher resolution and image quality, electrostatic image developing toners using toner matrix particles with high circularity have been adopted. Patent Document 1 describes a toner having a core-shell structure, which aims to provide a toner that can improve cleaning performance by exhibiting excellent polishing performance, and is characterized in that the shell layer of the toner contains abrasive fine particles with an average particle size of 0.1 to 1.0 μm in a ratio of 0.3 to 3.0 parts by weight per 100 parts by weight of toner. Furthermore, Patent Document 2 describes an electrostatic image developing toner that is less prone to filming on the photoreceptor, imparts stable chargeability to toner particles over time, is less prone to image quality degradation due to fogging etc. even when printing many sheets continuously, and is particularly less prone to image quality degradation even in high temperature and high humidity environments. The toner contains specific amounts of fatty acid zinc particles with a number average primary particle size of 0.5 to 1.5 μm, silica fine particles (A) with a solid average primary particle diameter of 5 to 20 nm, and silica fine particles (B) with a number average primary particle size of 25 to 80 nm as external additives. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2007-187988 [Patent Document 2] Japanese Patent Publication No. 2011-203666 [Overview of the project] [Problems that the invention aims to solve]

[0004] The electrostatic image developing toners described in Patent Documents 1 and 2 had the problem that the uniformity of the toner charge was not sufficient, and therefore the occurrence of fogging could not be adequately suppressed. Furthermore, the optimization of the toner transport amount had not been considered. The present invention relates to providing a toner for electrostatic image development that suppresses fogging even during continuous printing with low toner consumption, and furthermore, provides high stability of image density. [Means for solving the problem]

[0005] The inventors have found that the above problem can be solved by adding small-particle-sized silica particles and large-particle-sized silica particles having a specific particle size in a specific ratio to toner matrix particles having high circularity.

[0006] In other words, the present invention relates to the following [1]. [1] Toner matrix particles with a circularity of 0.965 or higher, Small silica particles with a particle size of 10 nm to 30 nm, calculated from the specific surface area, Large silica particles with a particle size of 70 nm to 190 nm, calculated from the specific surface area, are added externally. The mass ratio of large-particle-sized silica particles to small-particle-sized silica particles (large-particle-sized silica particles / small-particle-sized silica particles) is between 7 and 18. Toner for developing electrostatic images. [Effects of the Invention]

[0007] According to the present invention, even in continuous printing with low toner consumption, the occurrence of fogging is suppressed, and a toner for electrostatic image development with high image density stability can be provided. [Modes for carrying out the invention]

[0008] [Toner for electrostatic charge image development] The toner for electrostatic charge image development of the present invention (hereinafter, also simply referred to as "toner") is obtained by externally adding small particle size silica particles having a particle size in terms of specific surface area of 10 nm or more and 30 nm or less and large particle size silica particles having a particle size in terms of specific surface area of 70 nm or more and 190 nm or less to toner mother particles having a circularity of 0.965 or more, and the mass ratio of the addition amounts of the large particle size silica particles and the small particle size silica particles (large particle size silica particles / small particle size silica particles) is 7 or more and 18 or less. In the following description, the toner for electrostatic charge image development contains toner mother particles and an external additive, and preferably consists of toner mother particles and an external additive. Also, each particle of the toner for electrostatic charge image development will also be referred to as a "toner particle".

[0009] In the non-magnetic one-component development system, it is required that when the toner conveyed from the development roller passes through the development blade, each toner particle is instantaneously and uniformly triboelectrically charged. However, in the case of a toner having a high circularity, the friction between the development blade and the toner particles becomes small, and it becomes difficult to uniformly triboelectrically charge, so there is a problem that fogging is likely to occur. Also, since the friction between the development roller and the toner particles also becomes small, the adhesion of the toner to the development roller decreases, and it is impossible to ensure a stable conveyance amount, resulting in a problem that the image density cannot be guaranteed. According to the present invention, there is provided a toner for electrostatic charge image development in which fogging is suppressed even in continuous printing in a state where the toner consumption is small, and further, the stability of the image density is high. The reason for obtaining the above effects is not clear, but it is considered as follows. By combining small particle size silica having a particle size in terms of specific surface area of 10 nm or more and 30 nm or less and large particle size silica having a particle size in terms of specific surface area of 70 nm or more and 190 nm or less as external additives at a specific addition amount ratio, minute surface irregularities due to the external additives are created on the surface of the toner, and the effect of triboelectric charging acting between the development blade and the toner particles is improved. Therefore, it is considered that the charging uniformity of the toner is improved and fogging is suppressed. On the other hand, increasing the friction between the developing blade and the toner particles also increases the friction between the developing roller and the toner particles, thus increasing the amount of toner transported on the developing roller. If the friction between the developing roller and the toner particles increases excessively, toner leakage is more likely to occur through the gap between the developing roller and the developing blade. However, in this invention, by applying a specific additive ratio, the frictional force between the developing roller and the toner particles does not increase more than necessary, so the amount of toner transported is optimized, and it is presumed that toner leakage is suppressed. The above-described mechanism for the effects of the present invention is a hypothesis and is not limited thereto.

[0010] The definitions of various terms used in this specification are shown below. Whether a resin is crystalline or amorphous is determined by its 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 in which the crystallinity index is 0.6 or higher and 1.4 or lower. An amorphous resin is one in which no endothermic peak is observed, or if observed, the crystallinity index is less than 0.6 or greater than 1.4. The crystallinity index can be appropriately adjusted depending on the type and ratio of raw material monomers, as well as manufacturing conditions such as reaction temperature, reaction time, and cooling rate. In this 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 acid, and alkyl esters of each carboxylic acid (alkyl group having 1 to 3 carbon atoms). "Volume-intermediate particle size (D 50 ")" refers to the particle size at which the cumulative volume frequency calculated using volume fractions accounts for 50% of the total volume frequency, starting from the smallest particle size. The coefficient of variation of the particle size distribution (hereinafter also simply referred to as the "CV value") is a value expressed by the following formula. In the following formula, the volume-average particle size is the particle size obtained by dividing the sum of the product of the particle size and the volume of each measured particle by the total volume of the measured particles. CV value (%) = [Standard deviation of particle size distribution (μm) / Volume-average particle size (μm)] × 100

[0011] <Toner matrix particles> In this invention, the circularity of the toner matrix particles is 0.965 or higher. A circularity of 0.965 or higher allows for the acquisition of high-resolution images. The circularity of the toner matrix particles is preferably 0.965 or higher, more preferably 0.968 or higher, and more preferably 0.970 or higher, from the viewpoint of obtaining a high-definition image, and more preferably 0.995 or lower, more preferably 0.990 or lower, even more preferably 0.985 or lower, and even more preferably 0.980 or lower, from the viewpoint of further suppressing the occurrence of fogging. The circularity of the toner matrix particles is measured by the method described in the examples.

[0012] The toner matrix particles preferably contain a binder resin, and in addition to the binder resin, they preferably also contain a colorant and a release agent. The toner matrix particles may be obtained by any known method such as melt-kneading, emulsification-phase inversion, polymerization, or agglomeration-fusion. However, from the viewpoint of obtaining the desired circularity, the toner matrix particles obtained by agglomeration-fusion are preferred, and the toner matrix particles having a core-shell structure are more preferred. The following describes preferred embodiments of the toner matrix particles, but in the present invention, the toner matrix particles are not particularly limited as long as they have the circularity described above.

[0013] [Binding resin] From the viewpoint of excellent low-temperature fixation and obtaining the desired circularity, the toner matrix particles preferably contain a polyester resin as a binder resin, more preferably amorphous polyester resin A, and even more preferably amorphous polyester resin A and crystalline polyester resin C.

[0014] Amorphous polyester resin A In the present invention, the toner matrix particles preferably contain amorphous polyester resin A as a binder resin, and more preferably the core portion contains amorphous polyester resin A. Amorphous polyester resin A is, for example, an amorphous polyester resin containing a polycondensate of an alcohol component and a carboxylic acid component. Examples of amorphous polyester resins include polyester resins and modified polyester resins. Examples of modified polyester resins include urethane-modified polyester resins, epoxy-modified polyester resins, and composite resins containing polyester resin segments and addition polymerization resin segments. Among these, amorphous composite resins containing a polyester resin segment which is a polycondensate of an alcohol component and a carboxylic acid component, and an addition polymerization resin segment which is an addition polymerization product of raw material monomers containing a styrene-based compound, are preferred.

[0015] Examples of alcohol components include alkylene oxide adducts of aromatic diols, linear or branched aliphatic diols, alicyclic diols, and polyhydric alcohols of trivalent or higher. Among these, alkylene oxide adducts of aromatic diols are preferred from the viewpoint of obtaining a toner with excellent low-temperature fixation properties. The alkylene oxide adduct of an aromatic diol is preferably an alkylene oxide adduct of bisphenol A, and more preferably of formula (I):

[0016] [ka] (In the formula, OR 1 and R 2 O is an oxyalkylene group, R 1 and R 2 This is an alkylene oxide adduct of bisphenol A, where x and y are independently either an ethylene group or a propylene group, x and y represent the average number of moles of alkylene oxide added, each being a positive number, and the sum of x and y is between 1 and 16.

[0017] Examples of alkylene oxide adducts of bisphenol A include propylene oxide adducts of bisphenol A [2,2-bis(4-hydroxyphenyl)propane] and ethylene oxide adducts of bisphenol A. One or more of these may be used. Among these, propylene oxide adducts of bisphenol A are preferred. The content of the bisphenol A alkylene oxide adduct is preferably 70 mol% or more, more preferably 90 mol% or more, even more preferably 95 mol% or more, and 100 mol% or less, and even more preferably 100 mol%, in the alcohol component.

[0018] Examples of linear or branched aliphatic diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2,2-dimethyl-1,3-propanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, and 1,12-dodecanediol. Examples of alicyclic diols include hydrogenated bisphenol A [2,2-bis(4-hydroxycyclohexyl)propane] and alkylene oxide adducts of hydrogenated bisphenol A with 2 to 4 carbon atoms (average number of added moles: 2 to 12). Examples of polyhydric alcohols with a valency of 3 or higher include glycerin, pentaerythritol, trimethylolpropane, and sorbitol. These alcohol components may be used individually or in combination of two or more types.

[0019] Examples of carboxylic acid components include dicarboxylic acids and polycarboxylic acids with a valency of three or more. Examples of dicarboxylic acids include aromatic dicarboxylic acids, linear or branched aliphatic dicarboxylic acids, and alicyclic dicarboxylic acids. Among these, at least one selected from aromatic dicarboxylic acids and linear or branched aliphatic dicarboxylic acids is preferred. Examples of aromatic dicarboxylic acids include phthalic acid, isophthalic acid, and terephthalic acid. Among these, isophthalic acid and terephthalic acid are preferred, and terephthalic acid is more preferred. The amount of aromatic dicarboxylic acid is preferably 20 mol% or more, more preferably 30 mol% or more, even more preferably 40 mol% or more, even more preferably 50 mol% or more, and preferably 90 mol% or less, more preferably 85 mol% or less, and even more preferably 80 mol% or less, in the carboxylic acid component.

[0020] The number of carbon atoms in the linear or branched aliphatic dicarboxylic acid is preferably 2 or more, more preferably 3 or more, and preferably 30 or less, more preferably 20 or less. Examples of linear or branched aliphatic dicarboxylic acids include oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid, sebacic acid, dodecanediic acid, azelaic acid, and succinic acid substituted with an aliphatic hydrocarbon group having 1 to 20 carbon atoms. Examples of succinic acid substituted with an aliphatic hydrocarbon group having 1 to 20 carbon atoms include dodecyl succinic acid, dodecenyl succinic acid, and octenyl succinic acid. Among these, fumaric acid, sebacic acid, and succinic acid substituted with an aliphatic hydrocarbon group having 1 to 20 carbon atoms are preferred, and fumaric acid and sebacic acid are more preferred. The amount of linear or branched aliphatic dicarboxylic acid is preferably 1 mol% or more, more preferably 3 mol% or more, even more preferably 10 mol% or more, and preferably 80 mol% or less, more preferably 50 mol% or less, and even more preferably 30 mol% or less, in the carboxylic acid component.

[0021] The polycarboxylic acid with a valency of 3 or higher is preferably a trivalent carboxylic acid, such as trimellitic acid. Preferably, it is trimellitic acid or its anhydride. When a polycarboxylic acid with three or more valent properties is included, the amount of the polycarboxylic acid with three or more valent properties is preferably 3 mol% or more, more preferably 5 mol% or more, even more preferably 8 mol% or more, and preferably 30 mol% or less, more preferably 25 mol% or less, and even more preferably 20 mol% or less, in the carboxylic acid component. These carboxylic acid components may be used individually or in combination of two or more types.

[0022] The equivalent ratio [COOH group / OH group] of the carboxyl group of the carboxylic acid component to the hydroxyl group of the alcohol component is preferably 0.7 or higher, more preferably 0.8 or higher, and preferably 1.3 or lower, more preferably 1.2 or lower.

[0023] The addition polymerization resin segment is, for example, an addition polymerization product of raw material monomers containing styrene compounds. Examples of styrene compounds include unsubstituted or substituted styrene. Examples of substituents that can be substituted for styrene include alkyl groups having 1 to 5 carbon atoms, halogen atoms, alkoxy groups having 1 to 5 carbon atoms, sulfonic acid groups, or salts thereof. Examples of styrene-based compounds include styrene, methylstyrene, α-methylstyrene, β-methylstyrene, tert-butylstyrene, chlorostyrene, chloromethylstyrene, methoxystyrene, styrene sulfonic acid, or salts thereof. Among these, styrene is preferred. The content of styrene compounds in the raw material monomers of the addition polymerization resin segment is preferably 50% by mass or more, more preferably 65% ​​by mass or more, even more preferably 75% by mass or more, and 100% by mass or less, preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less.

[0024] Other raw material monomers besides styrene compounds include, for example, (meth)acrylic acid esters such as alkyl (meth)acrylate, benzyl (meth)acrylate, and dimethylaminoethyl (meth)acrylate; olefins such as ethylene, propylene, and butadiene; halovinyls such as vinyl chloride; vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as methyl vinyl ether; vinylidene halides such as vinylidene chloride; and N-vinyl compounds such as N-vinylpyrrolidone. Among these, (meth)acrylic acid esters are preferred, and alkyl (meth)acrylate is more preferred. The number of carbon atoms in the alkyl group of (meth)acrylate is preferably 1 or more, more preferably 4 or more, even more preferably 6 or more, and preferably 24 or less, more preferably 22 or less, and even more preferably 20 or less. Examples of alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, iso(or tertiary)butyl (meth)acrylate, isoamyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, isodecyl (meth)acrylate, isododecyl (meth)acrylate, isopalmityl (meth)acrylate, isostearyl (meth)acrylate, isobehenyl (meth)acrylate, and so on. Preferably, 2-ethylhexyl (meth)acrylate or stearyl (meth)acrylate is preferred, more preferably 2-ethylhexyl acrylate, stearyl methacrylate, and even more preferably stearyl methacrylate. Note that "(iso or tertiary)" and "(iso)" refer to both cases where these prefixes are present and where they are not, and the absence of these prefixes indicates the normal form. Also, "(meth)acrylic acid" refers to acrylic acid or methacrylic acid.

[0025] The content of (meth)acrylic acid ester in the raw material monomer of the addition polymerization resin segment is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and preferably 50% by mass or less, more preferably 35% by mass or less, and even more preferably 25% by mass or less. The total amount of styrene compounds and (meth)acrylic acid esters in the raw material monomers of the addition polymerization resin segment is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and even more preferably 100% by mass.

[0026] The amorphous polyester resin A preferably has constituent units derived from both reactive monomers that are covalently bonded to the polyester resin segment and the addition polymerization resin segment. "Constituent units derived from both reactive monomers" refers to units formed by the reaction of the functional groups and addition polymerizable groups of both reactive monomers. Examples of addition polymerizable groups include carbon-carbon unsaturated bonds (ethylenically unsaturated bonds). Examples of both reactive monomers include addition polymerizable monomers having at least one functional group selected from hydroxyl groups, carboxyl groups, epoxy groups, primary amino groups, and secondary amino groups within the molecule. Among these, addition polymerizable monomers having at least one functional group selected from hydroxyl groups and carboxyl groups are preferred from the viewpoint of reactivity, and addition polymerizable monomers having carboxyl groups are more preferred. Examples of addition polymerizable monomers having a carboxyl group include acrylic acid, methacrylic acid, fumaric acid, and maleic acid. Among these, acrylic acid and methacrylic acid are preferred from the viewpoint of reactivity in both polycondensation and addition polymerization reactions, with acrylic acid being more preferred. When both reactive monomers are addition polymerizable monomers having a carboxyl group, the amount of constituent units derived from both reactive monomers is preferably 1 mol or more, more preferably 5 mol or more, even more preferably 8 mol or more, and preferably 30 mol or less, more preferably 25 mol or less, and even more preferably 20 mol or less, per 100 mol parts of the alcohol component of the polyester resin segment of amorphous polyester resin A.

[0027] The amorphous polyester resin A may further contain, in addition to the polyester resin segment and the addition polymerization resin segment, a constituent unit derived from a hydrocarbon wax having at least one of a carboxyl group and a hydroxyl group (a constituent unit derived from a hydrocarbon wax).

[0028] The content of polyester resin segments in amorphous polyester resin A is preferably 40% by mass or more, more preferably 45% by mass or more, even more preferably 55% by mass or more, and preferably 95% by mass or less, more preferably 85% by mass or less, and even more preferably 75% by mass or less, based on the total amount of polyester resin segments and addition polymerization resin segments. The constituent units derived from both reactive monomers are polyester resin segments.

[0029] The content of addition polymerization resin segments in amorphous polyester resin A is preferably 5% by mass or more, more preferably 15% by mass or more, even more preferably 25% by mass or more, and preferably 60% by mass or less, more preferably 55% by mass or less, and even more preferably 45% by mass or less, based on the total amount of polyester resin segments and addition polymerization resin segments. The constituent units derived from both reactive monomers are polyester resin segments.

[0030] The amount of constituent units derived from both reactive monomers in amorphous polyester resin A is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 0.8% by mass or more, and preferably 10% by mass or less, more preferably 7% by mass or less, and even more preferably 4% by mass or less, relative to the total amount of polyester resin segment and addition polymerization resin segment.

[0031] The amount of hydrocarbon wax-derived constituent units in amorphous polyester resin A is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and even more preferably 6 parts by mass or less, based on 100 parts by mass of the total amount of polyester resin segment and addition polymerization resin segment.

[0032] The above amounts are calculated based on the ratio of the raw material monomers for the polyester resin segment and the addition polymerization resin segment, the two reactive monomers, and the radical polymerization initiator, excluding the amount of dehydration due to polycondensation in the polyester resin segment, etc. When a radical polymerization initiator is used, the mass of the radical polymerization initiator is included in the calculation of the addition polymerization resin segment.

[0033] Amorphous polyester resin A may be produced, for example, by a method comprising step A of polycondensing an alcohol component and a carboxylic acid component, and step B of addition polymerization of the raw material monomers and both reactive monomers of the addition polymerization resin segment. If the amorphous polyester resin A further contains constituent units derived from hydrocarbon wax, in step A described above, for example, a polycondensation reaction of the alcohol component and the carboxylic acid component is carried out in the presence of a hydrocarbon wax having at least one of a hydroxyl group and a carboxyl group. Process A may be performed after process B, or process B may be performed after process A, or processes A and B may be performed simultaneously. In step A, a portion of the carboxylic acid component is subjected to a polycondensation reaction, and then step B is carried out. After that, the remaining carboxylic acid component is added to the polymerization system to further advance the polycondensation reaction in step A and the polycondensation reaction with the carboxyl groups of both reactive monomers or constituent parts derived from both reactive monomers.

[0034] In step A, if necessary, an esterification catalyst such as di(2-ethylhexanoate)tin(II), dibutyltin oxide, or titanium diisopropoxybis(triethanolamine) may be used in an amount of 0.01 parts by mass to 5 parts by mass per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component; and an esterification co-catalyst such as gallic acid (same as 3,4,5-trihydroxybenzoic acid) may be used in an amount of 0.001 parts by mass to 0.5 parts by mass per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component for polycondensation. Furthermore, when using monomers having unsaturated bonds, such as fumaric acid, in polycondensation, a radical polymerization inhibitor may be used, preferably in an amount of 0.001 parts by mass or more and 0.5 parts by mass or less, per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. An example of a radical polymerization inhibitor is 4-tert-butylcatechol. The temperature of the polycondensation reaction is preferably 120°C or higher, more preferably 160°C or higher, even more preferably 180°C or higher, and preferably 250°C or lower, more preferably 240°C or lower. The polycondensation may be carried out in an inert gas atmosphere.

[0035] Examples of radical polymerization initiators for the addition polymerization in step B 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 radical polymerization initiator used is preferably 1 to 20 parts by mass per 100 parts by mass of raw material monomers of the addition polymerization resin segment. The addition polymerization temperature is preferably 110°C or higher, more preferably 130°C or higher, and preferably 230°C or lower, more preferably 220°C or lower, and even more preferably 210°C or lower.

[0036] (Physical properties of amorphous polyester resin A) The softening point of amorphous polyester resin A is preferably 70°C or higher, more preferably 90°C or higher, and even more preferably 100°C or higher. From the viewpoint of further improving low-temperature fixability, it is preferably 150°C or lower, more preferably 140°C or lower, and even more preferably 125°C or lower. The glass transition temperature of amorphous polyester resin A is preferably 30°C or higher, more preferably 35°C or higher, and even more preferably 40°C or higher, and from the viewpoint of further improving low-temperature fixability, it is preferably 80°C or lower, more preferably 70°C or lower, and even more preferably 60°C or lower.

[0037] The acid value of amorphous polyester resin A is preferably 5 mg KOH / g or more, more preferably 10 mg KOH / g or more, even more preferably 15 mg KOH / g or more, and preferably 40 mg KOH / g or less, more preferably 35 mg KOH / g or less, and even more preferably 30 mg KOH / g or less. The softening point, glass transition temperature, and acid value of amorphous polyester resin A can be appropriately adjusted depending on the type and amount of raw material monomer used, as well as manufacturing conditions such as reaction temperature, reaction time, and cooling rate. These values ​​can be determined by the method described in the examples. Furthermore, when using two or more amorphous polyester resins A in combination, it is preferable that the softening point, glass transition temperature, and acid value obtained from the mixture are all within the aforementioned ranges.

[0038] The content of amorphous polyester resin A is preferably 40% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, even more preferably 65% ​​by mass or more, and 100% by mass or less, preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 87% by mass or less, based on the total amount of resin components in the core.

[0039] ≪Crystalline polyester resin C≫ In the present invention, the toner matrix particles preferably contain crystalline polyester resin C, more preferably the toner matrix particles have a core-shell structure and contain crystalline polyester resin C in the core portion, and even more preferably contain crystalline polyester resin C only in the core portion.

[0040] Crystalline polyester resin C is, for example, a crystalline polyester resin which is a polycondensate of an alcohol component and a carboxylic acid component. As the alcohol component, α,ω-aliphatic diols are preferred. The number of carbon atoms in the α,ω-aliphatic diol is preferably 2 or more, more preferably 4 or more, even more preferably 6 or more, and preferably 16 or less, more preferably 14 or less, and even more preferably 12 or less. 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, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, and 1,12-dodecanediol are preferred, with 1,10-decanediol being more preferred.

[0041] The amount of α,ω-aliphatic diol 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 100 mol% or less, and even more preferably 100 mol%, in the alcohol component.

[0042] The alcohol component may contain other alcohol components other than α,ω-aliphatic diols. 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 trivalent or higher alcohols such as glycerin, pentaerythritol, and trimethylolpropane. One or more of these alcohol components may be used.

[0043] As the carboxylic acid component, aliphatic dicarboxylic acids are preferred, and linear aliphatic dicarboxylic acids are more preferred. The number of carbon atoms in the aliphatic dicarboxylic acid is preferably 4 or more, more preferably 8 or more, even more preferably 10 or more, and preferably 14 or less, more preferably 12 or less. Examples of aliphatic dicarboxylic acids include fumaric acid, sebacic acid, dodecanediic acid, and tetradecanediic acid. Among these, sebacic acid and tetradecanediic acid are preferred, with sebacic acid being more preferred. One or more of these carboxylic acid components may be used.

[0044] The amount of aliphatic dicarboxylic acid 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 100 mol% or less, and even more preferably 100 mol%, in the carboxylic acid component.

[0045] The carboxylic acid component may include other carboxylic acid components other than aliphatic dicarboxylic acids. Examples of other carboxylic acid components include aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid; and polycarboxylic acids with a valency of three or more. One or more of these carboxylic acid components may be used.

[0046] The equivalent ratio [COOH group / OH group] of the carboxyl group of the carboxylic acid component to the hydroxyl group of the alcohol component is preferably 0.7 or higher, more preferably 0.8 or higher, and preferably 1.3 or lower, more preferably 1.2 or lower.

[0047] Crystalline polyester resin C is produced, for example, by polycondensation of an alcohol component and a carboxylic acid component. During polycondensation, if necessary, an esterification catalyst such as di(2-ethylhexanoate)tin(II), dibutyltin oxide, or titanium diisopropoxybis(triethanolamine) may be used in an amount of 0.01 parts by mass to 5 parts by mass per 100 parts by mass of the total amount of the alcohol component and carboxylic acid component; and an esterification co-catalyst such as gallic acid (same as 3,4,5-trihydroxybenzoic acid) may be used in an amount of 0.001 parts by mass to 0.5 parts by mass per 100 parts by mass of the total amount of the alcohol component and carboxylic acid component. Furthermore, when using monomers having unsaturated bonds, such as fumaric acid, in polycondensation, a radical polymerization inhibitor may be used, preferably in an amount of 0.001 parts by mass or more and 0.5 parts by mass or less, per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. An example of a radical polymerization inhibitor is 4-tert-butylcatechol. The temperature of the polycondensation reaction is preferably 120°C or higher, more preferably 160°C or higher, even more preferably 180°C or higher, and preferably 250°C or lower, more preferably 240°C or lower. The polycondensation may be carried out in an inert gas atmosphere.

[0048] (Physical properties of crystalline polyester resin C) The softening point of the crystalline polyester resin C is preferably 60°C or higher, more preferably 70°C or higher, and even more preferably 80°C or higher, from the viewpoint of toner storage properties, and preferably 150°C or lower, more preferably 120°C or lower, even more preferably 100°C or lower, and even more preferably 95°C or lower, from the viewpoint of further improving low-temperature fixation properties. The melting point of the crystalline polyester resin C is preferably 50°C or higher, more preferably 60°C or higher, and even more preferably 70°C or higher, from the viewpoint of toner storage properties, and preferably 100°C or lower, more preferably 90°C or lower, even more preferably 85°C or lower, and even more preferably 80°C or lower, from the viewpoint of further improving low-temperature fixability.

[0049] The acid value of the crystalline polyester resin C is preferably 5 mg KOH / g or more, more preferably 10 mg KOH / g or more, even more preferably 15 mg KOH / g or more, and preferably 35 mg KOH / g or less, more preferably 25 mg KOH / g or less, and even more preferably 20 mg KOH / g or less.

[0050] The softening point, melting point, and acid value of crystalline polyester resin C can be appropriately adjusted depending on the type and amount of raw material monomer used, as well as manufacturing conditions such as reaction temperature, reaction time, and cooling rate, and can be determined by the method described in the examples below. When two or more types of crystalline polyester resin C are used in combination, it is preferable that the softening point, melting point, and acid value obtained as a mixture thereof are within the aforementioned ranges.

[0051] When amorphous polyester resin A and crystalline polyester resin C are used in combination, the mass ratio of amorphous polyester resin A to crystalline polyester resin C [amorphous polyester resin A / crystalline polyester resin C] is preferably 40 / 60 or more, more preferably 50 / 50 or more, even more preferably 60 / 40 or more, even more preferably 65 / 35 or more, and preferably 95 / 5 or less, more preferably 90 / 10 or less, even more preferably 85 / 15 or less, and even more preferably 75 / 25 or less.

[0052] [Core-shell structure] The toner of the present invention has a core-shell structure, and it is preferable that the core portion contains the crystalline polyester resin C and amorphous polyester resin A. Furthermore, it is preferable that the core portion contains a colorant and a release agent in addition to the crystalline polyester resin C and amorphous polyester resin A.

[0053] In the present invention, the shell content in the toner particles is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, even more preferably 7 parts by mass or more, even more preferably 10 parts by mass or more, and preferably 30 parts by mass or less, more preferably 25 parts by mass or less, and even more preferably 20 parts by mass or less, from the viewpoint of obtaining a high-resolution image, per 100 parts by mass of toner matrix particles. The shell in the toner preferably contains an amorphous polyester resin B, as described later, and more preferably the shell is made of amorphous polyester resin B. The amount of shell binder resin in 100 parts by mass of toner binder resin is 5 parts by mass or more, preferably 7 parts by mass or more, more preferably 10 parts by mass or more, and 30 parts by mass or less, preferably 25 parts by mass or less, more preferably 20 parts by mass or less, from the viewpoint of obtaining a high-definition image.

[0054] Amorphous polyester resin B In the present invention, the toner matrix particles preferably contain amorphous polyester resin B as a binder resin in addition to the crystalline polyester resin C and amorphous polyester resin A, and it is more preferable that the shell contains amorphous polyester resin B. The amorphous polyester resin B is preferably an amorphous polyester resin containing, for example, a polycondensate of an alcohol component and a carboxylic acid component. Examples of polyester resins include polyester resins and modified polyester resins. Examples of modified polyester resins include urethane-modified polyester resins, epoxy-modified polyester resins, and composite resins containing polyester resin segments and addition polymerization resin segments. Among these, amorphous polyester resins that are polycondensates of alcohol and carboxylic acid components are preferred.

[0055] The alcohol component can be an alkylene oxide adduct of an aromatic diol, a linear or branched aliphatic diol, an alicyclic diol, or a polyhydric alcohol of trihydric or higher hydric value, similar to the alcohol component of the polyester resin segment of amorphous polyester resin A described above. Among these, from the viewpoint of obtaining a toner with excellent low-temperature fixation properties, an alkylene oxide adduct of an aromatic diol is preferred, more preferably an alkylene oxide adduct of bisphenol A, and even more preferably a propylene oxide adduct of bisphenol A [2,2-bis(4-hydroxyphenyl)propane] or an ethylene oxide adduct of bisphenol A. One or more of these may be used. Among these, an ethylene oxide adduct of bisphenol A is more preferred.

[0056] Examples of carboxylic acid components include dicarboxylic acids and polycarboxylic acids with a valency of three or more, similar to the carboxylic acid components of the polyester resin segment of amorphous polyester resin A described above. Examples of dicarboxylic acids include aromatic dicarboxylic acids, linear or branched aliphatic dicarboxylic acids, and alicyclic dicarboxylic acids. Among these, at least one selected from aromatic dicarboxylic acids and linear or branched aliphatic dicarboxylic acids is preferred. The amount of aromatic dicarboxylic acid 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 95 mol% or less, more preferably 90 mol% or less, and even more preferably 85 mol% or less, in the carboxylic acid component.

[0057] The amount of linear or branched aliphatic dicarboxylic acid is preferably 1 mol% or more, more preferably 3 mol% or more, even more preferably 5 mol% or more, and preferably 60 mol% or less, more preferably 30 mol% or less, even more preferably 20 mol% or less, and even more preferably 15 mol% or less, in the carboxylic acid component.

[0058] When a polycarboxylic acid with three or more valent properties is included, the amount of the polycarboxylic acid with three or more valent properties is preferably 3 mol% or more, more preferably 5 mol% or more, even more preferably 8 mol% or more, and preferably 30 mol% or less, more preferably 25 mol% or less, and even more preferably 20 mol% or less, in the carboxylic acid component. These carboxylic acid components may be used individually or in combination of two or more types.

[0059] The equivalent ratio [COOH group / OH group] of the carboxyl group of the carboxylic acid component to the hydroxyl group of the alcohol component is preferably 0.7 or higher, more preferably 0.8 or higher, and preferably 1.3 or lower, more preferably 1.2 or lower.

[0060] Polyester resin B may be produced, for example, by step A, which involves polycondensation of an alcohol component and a carboxylic acid component. Step A is the same as Step A described in the method for producing amorphous polyester resin A, and the preferred range is also the same.

[0061] (Physical properties of amorphous polyester resin B) The softening point of amorphous polyester resin B is preferably 70°C or higher, more preferably 90°C or higher, and even more preferably 100°C or higher. From the viewpoint of further improving low-temperature fixability, it is preferably 150°C or lower, more preferably 140°C or lower, and even more preferably 125°C or lower. The glass transition temperature of amorphous polyester resin B is preferably 30°C or higher, more preferably 40°C or higher, and even more preferably 50°C or higher. From the viewpoint of further improving low-temperature fixability, it is preferably 90°C or lower, more preferably 80°C or lower, and even more preferably 70°C or lower.

[0062] The acid value of amorphous polyester resin B is preferably 5 mg KOH / g or more, more preferably 10 mg KOH / g or more, even more preferably 15 mg KOH / g or more, and preferably 40 mg KOH / g or less, more preferably 30 mg KOH / g or less, and even more preferably 25 mg KOH / g or less. The softening point, glass transition temperature, and acid value of amorphous polyester resin B can be appropriately adjusted depending on the type and amount of raw material monomer used, as well as manufacturing conditions such as reaction temperature, reaction time, and cooling rate. These values ​​can be determined by the method described in the examples. Furthermore, when using two or more amorphous polyester resins B in combination, it is preferable that the softening point, glass transition temperature, and acid value obtained from the mixture thereof are within the aforementioned ranges.

[0063] The content of amorphous polyester resin B is preferably 60% 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 100% by mass or less, and even more preferably 100% by mass, based on the total amount of resin components of the resin particles Y for the shell layer.

[0064] [Coloring agents] In the present invention, the toner matrix particles preferably contain a coloring agent, and it is preferable that the core portion contains a coloring agent. As a coloring agent, all dyes, pigments, etc. used as coloring agents for toners can be used. Examples of colorants include carbon black, phthalocyanine blue (e.g., pigment blue 15:3), permanent brown FG, brilliant first scarlet, pigment green B, rhodamine-B base, solvent red 49, solvent red 146, solvent blue 35, quinacridone, carmine 6B, and disazo yellow. The toner may be either black toner or a color toner other than black. The colorant content is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, and preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less, in the toner particles.

[0065] [Release agent] In the present invention, the toner matrix particles preferably contain a release agent, and it is more preferable that the core portion contains a release agent. Examples of release agents include polypropylene wax, polyethylene wax, polypropylene-polyethylene copolymer wax; hydrocarbon waxes such as microcrystalline wax, paraffin wax, Fischer-Tropsch wax, and sazole wax, or their oxides; ester waxes such as carnauba wax, montane wax, or their deoxidizing waxes, and fatty acid ester waxes; fatty acid amides, fatty acids, higher alcohols, and fatty acid metal salts. One or more of these may be used.

[0066] The melting point of the release agent is preferably 60°C or higher, more preferably 70°C or higher, and more 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 release agent content is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 3% by mass or more, even more preferably 5% by mass or more, and preferably 20% by mass or less, and more preferably 15% by mass or less, in the toner particles.

[0067] <Method for manufacturing toner matrix particles> The method for producing toner matrix particles is not particularly limited, as long as toner matrix particles with the desired circularity can be obtained. From the viewpoint of obtaining a desired circularity of 0.965 or higher, it is preferable to employ chemical methods such as emulsion polymerization or suspension. Furthermore, from the viewpoint of obtaining toner with excellent toner properties such as low-temperature fixability, it is preferable to obtain toner matrix particles by emulsification aggregation having the following steps 1 to 3. Step 1: A step of agglomerating resin particles X containing crystalline polyester resin C and amorphous polyester resin A in the same or different particles in an aqueous medium to obtain aggregated particles 1. Step 2: To obtain aggregated particles 2, resin particles Y containing amorphous polyester resin B are aggregated with aggregated particles 1 obtained in Step 1. Step 3: A step to obtain fused particles by heating the aggregated particles 2 obtained in Step 2 to fuse them together. Examples of methods for producing toner matrix particles by steps 1 to 3 include steps 1, 1', and 2 described in Japanese Patent Publication No. 2021-012242, and steps 1, 1', and 2 described in Japanese Patent Publication No. 2021-026129.

[0068] In step 1 described above, it is preferable to aggregate the resin particles X together with the coloring agent particles containing a coloring agent and the release agent particles containing a release agent. The dispersion of resin particles X is preferably obtained by a phase inversion emulsification method. Furthermore, it is preferable to incorporate the colorant particles into aggregated particles by mixing them with resin particles as a dispersion of colorant particles and agglomerating them. It is preferable to obtain the colorant by dispersing the colorant and an aqueous medium using a disperser such as a homogenizer or an ultrasonic disperser. From the viewpoint of improving the dispersion stability of the colorant, it is preferable to carry out this dispersion in the presence of an addition polymer (hereinafter, the addition polymer used for dispersing the colorant is also referred to as "addition polymer E") or a surfactant. Examples of such surfactants include nonionic surfactants, anionic surfactants, and cationic surfactants. The addition polymer E preferably has structural units derived from addition polymerizable monomer a having an aromatic group, and more preferably further contains at least one selected addition polymerizable monomer b having an ionic group, addition polymerizable monomer c having a polyalkylene oxide group, and macromonomer d. For the colorant particle dispersion and the addition polymer E, refer to the addition polymer E described in Japanese Patent Application Publication No. 2021-026129. Furthermore, it is preferable to incorporate the release agent particles into the aggregated particles by mixing them with a resin particle dispersion and a coloring agent particle dispersion as a dispersion of release agent particles and causing them to aggregate. While a dispersion of release agent particles can be obtained using a surfactant, it is preferable to obtain it by mixing the release agent with resin particles Z. By preparing release agent particles using the release agent and resin particles Z, the release agent particles are stabilized by the resin particles Z, making it possible to disperse the release agent in an aqueous medium without using a surfactant. In the dispersion of release agent particles, it is thought that the release agent particles have a structure in which many resin particles Z are attached to the surface. The resin constituting the resin particles Z that disperse the mold release agent is preferably a polyester resin, and it is more preferable to use a composite resin D having a polyester resin segment and an addition polymerization resin segment. For details on the mold release agent particle dispersion and the composite resin D, please refer to Japanese Patent Application Publication No. 2021-026129. Furthermore, a post-processing step may be performed after step 3, and it is preferable to obtain toner matrix particles by isolation. Since the particles obtained in step 3 are present in an aqueous medium, it is preferable to first perform solid-liquid separation, then wash and dry as necessary.

[0069] [Volume-average particle size of toner matrix particles] It is preferable to use a toner obtained by adding the following external additive to the surface of toner matrix particles obtained by drying, etc., as a toner for developing electrostatic images. Volume median particle size of toner matrix particles (D 50 From the viewpoint of improving toner productivity, obtaining the desired circularity, and improving the low-temperature fixability of the toner, the particle size is preferably 2 μm or more, more preferably 3 μm or more, even more preferably 4 μm or more, and preferably 10 μm or less, more preferably 8 μm or less, and even more preferably 6 μm or less. The CV value of the toner matrix particles is preferably 12% or more, more preferably 14% or more, and even more preferably 16% or more, from the viewpoint of improving toner productivity, and preferably 32% or less, more preferably 30% or less, and even more preferably 29% or less, from the viewpoint of obtaining high-quality images.

[0070] <External additives> In the present invention, the toner for developing electrostatic images is made by adding small silica particles with a particle size of 10 nm to 30 nm (calculated from the specific surface area) and large silica particles with a particle size of 70 nm to 190 nm (calculated from the specific surface area) to toner matrix particles with a circularity of 0.965 or more. Furthermore, the mass ratio of the amount of large silica particles to small silica particles added (large silica particles / small silica particles) is 7 to 18. When the mass ratio is 7 or higher, the surface irregularities of the toner are appropriate, moderate friction occurs with the developing blade, and the toner is uniformly charged, thus suppressing the occurrence of fogging. Also, moderate friction occurs with the developing roller, and the necessary amount of toner is transported, resulting in good image density. When the ratio is 18 or lower, the friction between the developing roller and the electrostatic image developing toner does not become excessively large, and the amount of toner transported does not increase too much, so the amount of toner scraped off by the developing blade is within an appropriate range, and the occurrence of toner leakage from the end of the developing roller is suppressed. The mass ratio of the amount of large-particle-sized silica particles added to the amount of small-particle-sized silica particles (large-particle-sized silica particles / small-particle-sized silica particles) is 7 or more, preferably 8 or more, more preferably 9 or more, even more preferably 10 or more, and 18 or less, preferably 16 or less, more preferably 15 or less, and even more preferably 14 or less.

[0071] The amount of small-particle silica particles added per 100 parts by mass of toner matrix particles is preferably 0.4 parts by mass or more, more preferably 0.45 parts by mass or more, and preferably 1.2 parts by mass or less, more preferably 1.0 part by mass or less, even more preferably 0.7 parts by mass or less, even more preferably 0.65 parts by mass or less, and even more preferably 0.6 parts by mass or less, from the viewpoint of improving transferability, suppressing the occurrence of fogging, and further improving the stability of image density. Furthermore, from a similar viewpoint, the amount of large-particle silica particles added per 100 parts by mass of toner matrix particles is preferably 5 parts by mass or more, more preferably 6 parts by mass or more, and preferably 18 parts by mass or less, more preferably 14 parts by mass or less, and even more preferably 10 parts by mass or less. The total addition amount of the large-particle-size silica particles and the small-particle-size silica particles with respect to 100 parts by mass of the toner mother particles is, from the same viewpoint, preferably 5.5 parts by mass or more, more preferably 6 parts by mass or more, still more preferably 6.5 parts by mass or more, and preferably 19 parts by mass or less, more preferably 15 parts by mass or less, still more preferably 12 parts by mass or less.

[0072] The small-particle-size silica particles have a particle size converted from the specific surface area of 10 nm or more, preferably 12 nm or more, more preferably 14 nm or more, still more preferably 16 nm or more, even more preferably 20 nm or more, and 30 nm or less, preferably 28 nm or less. Further, the large-particle-size silica particles have a particle size converted from the specific surface area of 70 nm or more, preferably 90 nm or more, more preferably 100 nm or more, and 190 nm or less, preferably 150 nm or less, more preferably 140 nm or less, still more preferably 125 nm or less. Note that the "particle size converted from the specific surface area" in the small-particle-size silica particles and the large-particle-size silica particles is measured by the method described in the examples.

[0073] When the toner to which the above small-particle-size silica particles and large-particle-size silica particles are externally added is plotted with the particle size on the horizontal axis and the particle mass having the particle size on the vertical axis as the whole external additive, it has two peaks at a particle size of 10 nm or more and 30 nm or less and at a particle size of 70 nm or more and 190 nm or less. Further, when the mass ratio of the particles having a particle size converted from the specific surface area in the external additive of 10 nm or more and 70 nm or less is W S and the mass ratio of the particles having a particle size converted from the specific surface area of more than 70 nm and 400 nm or less is W L When it is L / W S is preferably 7 or more, more preferably 8 or more, still more preferably 9 or more, even more preferably 10 or more, and preferably 18 or less, more preferably 16 or less, still more preferably 15 or less, even more preferably 14 or less.

[0074] From the viewpoint of improving toner transferability, it is preferable that the small-particle and large-particle silica particles are hydrophobic silica that has been treated to be hydrophobic. Examples of hydrophobic agents used to make the surface of silica particles hydrophobic include silane coupling agents and silicone oils. Silane coupling agents include disilazanes such as hexamethyldisilazane (HMDS); cyclic silazanes; trimethylsilane; trimethylchlorosilane; dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, benzyldimethylchlorosilane, methyltrimethoxysilane, methyltriethoxysilane, isobutyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, trimethylmethoxysilane, octyltriethoxysilane, hydroxypropyltrimethoxysilane, phenyltrimethoxysilane, n-octadecyltrimethoxysilane, vinyltrimeth Examples include alkylsilane compounds such as xysilane, vinyltriethoxysilane, γ-methacrylateoxypropyltrimethoxysilane, and vinyltriacetoxysilane, as well as aminosilane compounds such as γ-aminopropyltriethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)3-aminopropyltrimethoxysilane, and N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane. Examples of the above-mentioned silicone oils include polydimethylsiloxane, polymethylhydrogensiloxane, polymethylphenylsiloxane, and amino-modified silicone oils. Among these, hexamethyldisilazane (HMDS), dimethyldichlorosilane (DMDS), polydimethylsiloxane, octyltriethoxysilane (OTES), and polydimethylsiloxane are preferred. These can be used individually or in combination of two or more types.

[0075] A mixer such as a Henschel mixer can be used to mix the toner base particles with the external additive.

[0076] In addition to the small-particle and large-particle silica particles mentioned above, charged particles (charge aids) may also be added to the toner matrix particles. Furthermore, it is preferable to add charged particles having a different charging polarity from that of the toner matrix particles. If the toner matrix particles are positively charged, it is preferable to add negatively charged particles, and if the toner matrix particles are negatively charged, it is preferable to add positively charged particles. In this case, if the toner matrix particles are toner matrix particles having a polyester-based resin as a binder resin as described above, it is preferable to add positively charged particles externally, since the toner matrix particles are negatively charged. The number-average primary particle size of the charged particles is preferably 0.10 μm or more and 1.50 μm or less. More preferably 0.150 μm or more and 1.00 μm or less. Having such charged particles is preferable because it results in good transfer efficiency throughout continuous use. This is thought to be because the charged particles of this size can roll on the surface of the toner particles, promoting toner charging and consequently suppressing the decrease in charge due to the application of a transfer bias.

[0077] Examples of positively charged particles include hydrotalcite particles, titanium dioxide particles, benzoguanamine resin particles, benzoguanamine-melamine resin particles, melamine resin particles, and melamine-formaldehyde resin particles. Among these, melamine-formaldehyde resin particles are particularly preferred. Examples of negatively charged particles include polytetrafluoroethylene particles, trifluoroethylene particles, vinylidene fluoride particles, and fluoroethylene resin particles.

[0078] The amount of charged particles added per 100 parts by mass of toner matrix particles is preferably 0.005 parts by mass or more, more preferably 0.01 parts by mass or more, even more preferably 0.03 parts by mass or more, and preferably 1.0 part by mass or less, more preferably 0.3 parts by mass or less, and even more preferably 0.1 parts by mass or less.

[0079] ≪Toner for developing electrostatic images≫ The electrostatic image developing toner obtained as described above can be used as a one-component developer or, when mixed with a carrier, as a two-component developer. Among these, it is preferred as a one-component developer and more preferred as a non-magnetic one-component developer. [Examples]

[0080] The present invention will be specifically described below with reference to examples, but the present invention is not limited in any way by these examples. Each property value was measured and evaluated by the following method. In notations such as "alkylene oxide (X)," the number X in parentheses represents the average number of moles of alkylene oxide added.

[0081] [measurement] [Acid value of resins] Measurements were performed according to JIS K0070:1992, except that chloroform was used as the measurement solvent.

[0082] [Resin softening point, crystallinity index, melting point, glass transition temperature] (1) Softening point Using a flow tester "CFT-500D" (manufactured by Shimadzu Corporation), 1 g of sample was heated at a heating rate of 6°C / min while a load of 1.96 MPa was applied by a plunger, and the sample was extruded from a nozzle with a diameter of 1 mm and a length of 1 mm. The amount of plunger descent of the flow tester was plotted against temperature, and the temperature at which half of the sample flowed out was defined as the softening point.

[0083] (2) Crystallinity index Using a differential scanning calorimeter "Q100" (manufactured by T.A. Instruments Japan Co., Ltd.), 0.02 g of the sample was weighed into an aluminum pan and cooled to 0°C at a cooling rate of 10°C / min. The sample was then left to stand still for 1 minute, and then heated to 180°C at a heating rate of 10°C / min, and the amount of heat was measured. Among the observed endothermic peaks, the temperature of the peak with the largest peak area was defined as the maximum endothermic peak temperature (1), and the crystallinity index was determined by (softening point (°C)) / (maximum endothermic peak temperature (1) (°C)).

[0084] (3) Melting point and glass transition temperature Using a differential scanning calorimeter "Q100" (manufactured by T.A. Instruments Japan Co., Ltd.), 0.02 g of the sample was weighed into an aluminum pan, heated to 200°C, and then cooled to 0°C at a rate of 10°C / min. The sample was then heated again at a rate of 10°C / min, and the amount of heat was measured. Among the observed endothermic peaks, the temperature of the peak with the largest peak area was defined as the maximum endothermic peak temperature (2). In the case of crystalline resins, this peak temperature was defined as the melting point. Furthermore, in the case of amorphous resins, if a peak was observed, the temperature of that peak was defined as the glass transition temperature. If no peak was observed but a step was observed, the temperature at the intersection of the tangent line showing the maximum slope of the curve in the step portion and the extension of the baseline on the low-temperature side of the step was defined as the glass transition temperature.

[0085] [Weight-average molecular weight of addition polymers] The solutions prepared by dissolving phosphoric acid and lithium bromide in N,N-dimethylformamide at concentrations of 60 mmol / L and 50 mmol / L, respectively, were used as eluents. The results were measured using gel permeation chromatography (GPC instrument "HLC-8320GPC" (Tosoh Corporation), columns "TSKgel SuperAWM-H", "TSKgel SuperAW3000", "TSKgel guardcolum Super AW-H" (Tosoh Corporation), flow rate: 0.5 mL / min) and monodisperse polystyrene kits with known molecular weights as standard substances (PStQuick B (F-550, F-80, F-10, F-1, A-1000), PStQuick C (F-288, F-40, F-4, A-5000, A-500), Tosoh Corporation) as the eluents.

[0086] [Melting point of release agent] Using a differential scanning calorimeter "Q100" (manufactured by T.A. Instruments Japan Co., Ltd.), 0.02 g of the sample was weighed into an aluminum pan, heated to 200°C, and then cooled to 0°C at a rate of 10°C / min. The sample was then heated again at a rate of 10°C / min, the amount of heat was measured, and the maximum endothermic peak temperature was defined as the melting point.

[0087] [Volume-intermediate particle size D of resin particles, release agent particles, and colorant particles] 50 [and CV value] (1) Measuring device: Laser diffraction particle size analyzer "LA-920" (manufactured by Horiba, Ltd.) (2) Measurement conditions: Distilled water is added to the measuring cell, and the absorbance is measured at a concentration that is within the appropriate range for the median particle size D 50 The volume-average particle size was also measured. Furthermore, the CV value (coefficient of variation of particle size distribution, %) was calculated according to the following formula. CV value (%) = (Standard deviation of particle size distribution / Volume-average particle size) × 100

[0088] [Solid content concentration of resin particle dispersion, mold release agent particle dispersion, and colorant particle dispersion] Using an infrared moisture meter "FD-230" (manufactured by Kett Scientific Research Institute Co., Ltd.), the moisture content (mass%) of a 5g 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 concentration (mass%) = 100-moisture (mass%)

[0089] [Volume-intermediate particle size D of aggregated particles] 50 [and CV value] Volume-intermediate particle size D of aggregated particles 50 The following measurements were taken. • 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" (manufactured by Beckman Coulter, Inc.) • Electrolyte: "Isoton (registered trademark) II" (manufactured by Beckman Coulter, Inc.) • Measurement conditions: The sample dispersion was added to 100 mL of the electrolyte solution to adjust the concentration to one that could measure the particle size of 30,000 particles in 20 seconds. Then, the 30,000 particles were measured, and the volume median particle size D was determined from the particle size distribution. 50 The volume-average particle size was determined. Furthermore, the CV value (coefficient of variation of particle size distribution, %) was calculated according to the following formula. CV value (%) = (Standard deviation of particle size distribution / Volume-average particle size) × 100

[0090] [Circularity of fused particles and toner matrix particles] The circularity of the fused particles and toner matrix particles was measured under the following conditions. • Measurement device: Flow-type particle image analyzer "FPIA-3000" (manufactured by Sysmex Corporation) • Preparation of dispersion: The dispersion of fused particles or toner mother particles was prepared by diluting it with deionized water to a solid content concentration of 0.001 to 0.05% by mass. • Measurement mode: HPF measurement mode

[0091] [Toner particle volume median particle size D] 50 [and CV value] Volume-intermediate particle size D of toner particles 50 The following measurements were taken. The measuring instrument, aperture diameter, analysis software, and electrolyte are used to determine the volume-median particle size D of the aggregated particles. 50 We used something similar to that. • Dispersion: Polyoxyethylene lauryl ether "Emulgen (registered trademark) 109P" (manufactured by Kao Corporation, HLB: 13.6) was dissolved in the electrolyte to obtain a dispersion with a concentration of 5% by mass. • Dispersion conditions: 10 mg of toner measurement sample was added to 5 mL of the dispersion, dispersed for 1 minute using an ultrasonic disperser, then 25 mL of electrolyte was added, and dispersed again for 1 minute using an ultrasonic disperser to prepare the sample dispersion. • Measurement conditions: The sample dispersion is added to 100 mL of the electrolyte to adjust the concentration to a level that allows for the measurement of 30,000 particle sizes in 20 seconds. Then, 30,000 particles are measured, and the volume median particle size D is determined from the particle size distribution. 50 The volume-average particle size was also determined. Furthermore, the CV value (coefficient of variation of particle size distribution, %) was calculated according to the following formula. CV value (%) = (Standard deviation of particle size distribution / Volume-average particle size) × 100

[0092] [Particle size of external additives] The particle size of the external additive is assumed to be perfectly spherical, and the density of the silica particles, which are the external additive, is 2.2 g / cm³. 2 The specific surface area was then calculated according to the following formula. Particle size (m)=6 / (specific surface area (m 2 / g) x density (g / m 3 )) The value of the specific surface area (m²) used in the above formula 2 The specific surface area ( / g) was obtained using the BET multipoint method with a specific surface area analyzer. In the BET multipoint method, the amount of adsorption was measured at three or more points within the equilibrium relative pressure range of 0.05 to 0.30 for the adsorbed gas (nitrogen), and the specific surface area was calculated. Specifically, the analysis was performed under the following measurement conditions. • Measuring instrument: Multi-sample high-performance specific surface area / pore distribution analyzer 3Flex-3MP (manufactured by micromeritics). • Dispersed adsorbent: Nitrogen Pre-treatment: 40°C for 4 hours or more • Equilibrium relative pressure: 0.05~0.30 (in increments of 0.05) • Balance interval: 10 seconds

[0093] [Evaluation Method] [Test conditions for paint leaks] A commercially available printer, "COREFIDO C712dnw" (manufactured by OKI Data Corporation), was equipped with toner and used to continuously print 2,000 images at a print density of 0.3% on "Excellent White Paper A4 size" (manufactured by OKI Data Corporation) at a temperature of 25°C and 50% humidity (NN environment). After that, the printer was left to stand for 12 hours at a temperature of 27°C and 80% humidity (HH environment), and then another 1,000 images were printed continuously in the HH environment, for a total of 3,000 images printed in both the NN and HH environments. Fogging was measured after the first print and then every 500 images thereafter. Measurements were also taken after the first print when switching from the NN environment to the HH environment.

[0094] [Measurement of flicker] The amount of fog was measured as follows. First, a blank sheet of paper was printed, and the printer was stopped midway through the blank printing process. The developing unit was removed from the printer, and "Scotch® Mending Tape 810" (manufactured by 3M Japan Ltd., width: 18mm) was attached to the photoconductor, and the toner on the photoconductor was peeled off with the tape. Tape peeled from the photoconductor and unused tape were attached to high-quality paper "Excellent White Paper A4 size" (manufactured by OKI Data Corporation). The peeled tape and unused tape were measured using a "SpectroEye" colorimeter (manufactured by Gretag Macbeth, lighting conditions: standard light source D50, observation field 2°, density standard DINNB, absolute white standard). The color difference (ΔE) between the peeled tape and the unused tape was defined as fogging. A smaller fogging value indicates a better image with less fogging. The results are shown in Table 5. The fogging value was calculated as the average of the measurement taken for the first print, measurements taken every 500 prints until a total of 3,000 prints were made under NN and HH environments, and the measurement taken for the first print when switching from the NN environment to the HH environment.

[0095] [Test conditions for conveying volume] A commercially available printer, "COREFIDO C712dnw" (manufactured by OKI Data Corporation), was equipped with toner and used to continuously print 2,000 images at a print density of 0.3% on "Excellent White Paper A4 size" (manufactured by OKI Data Corporation) at a temperature of 25°C and 50% humidity (NN environment). The printer was then left to stand for 12 hours at a temperature of 27°C and 80% humidity (HH environment), and another 1,000 images were printed continuously in the HH environment. A total of 3,000 images were printed in both the NN and HH environments. Toner transport volume was measured after the first print, and then every 1,000 prints thereafter. Toner transport volume was also measured for the first print after changing the environment from NN to HH.

[0096] [Measurement of transport volume] First, a solid image was printed, and the printer was stopped when half of the A4 sheet had been transferred. Three 1cm x 2cm jigs were attached to the developing roller, 3cm from each end and in the center of the developing roller. A Q / m meter "210HS" (manufactured by Trek) was used to suck up the toner from the developing roller. The amount of toner per unit area on the developing roller was calculated by dividing the amount of toner sucked up by the area over which it was sucked, and this was defined as the transport volume. The transport volume value was 0.20 mg / cm². 2 If the above is met, the image density after printing can be guaranteed, and in addition, 0.30 mg / cm²2 In the above scenario, toner leakage occurs from the end of the developing unit; therefore, a transport volume lower than this is desirable. Furthermore, it is desirable that the transport volume be stable regardless of the number of printed pages and the printing environment. The results are shown in Table 5. The transport volume values ​​were calculated as the average of the measurement taken when printing the first page, the measurement taken every 1,000 pages until a total of 3,000 pages were printed under NN and HH environments, and the measurement taken when switching from the NN environment to the HH environment. To determine whether the transport volume is stable, the standard deviation is also shown in Table 5.

[0097] [Resin manufacturing] [Manufacturing of amorphous resins] Manufacturing Example A1 (Manufacturing of Resin A-1) A 10 L four-necked flask equipped with a nitrogen inlet tube, dehydration tube, stirrer, and thermocouple was purged with nitrogen. 3356 g of bisphenol A propylene oxide (2,2) adduct, 955 g of terephthalic acid, 385 g of paracol 6490 (manufactured by Nippon Seiro), 25 g of tin(II) di(2-ethylhexanoate), and 2.5 g of 3,4,5-trihydroxybenzoic acid were added. Under a nitrogen atmosphere, the mixture was heated to 235°C with stirring and held at 235°C for 5 hours. After that, the pressure inside the flask was reduced and held at 8 kPa for 1 hour. After returning to atmospheric pressure, the mixture was cooled to 160°C and held at 160°C. A mixture of 2198 g of styrene, 550 g of stearyl methacrylate, 110 g of acrylic acid, and 330 g of dibutyl peroxide was added dropwise over 1 hour. The mixture was then held at 160°C for 30 minutes, then heated to 200°C, and the pressure inside the flask was reduced to 8 kPa and held for 1 hour. After returning to atmospheric pressure, it was cooled to 190°C, and 200 g of fumaric acid, 194 g of sebacic acid, 184 g of trimellitic anhydride, and 2.5 g of 4-tert-butylcatechol were added. The mixture was then heated to 210°C at a rate of 10°C / hr, and the reaction was carried out at 4 kPa until the desired softening point was reached to obtain resin A-1. The physical properties are shown in Table 1.

[0098] Manufacturing example A2 (Manufacturing of resin B-1) A four-necked flask equipped with a nitrogen inlet tube, dehydration tube, stirrer, and thermocouple was purged with nitrogen. 3265 g of bisphenol A ethylene oxide (2,2) adduct, 1334 g of terephthalic acid, 25 g of tin(II) di(2-ethylhexanoate), and 2.5 g of 3,4,5-trihydroxybenzoic acid were added. Under a nitrogen atmosphere, the mixture was heated to 235°C with stirring and held at 235°C for 6 hours. The pressure inside the flask was then reduced and held at 8.3 kPa for 1 hour. After returning to atmospheric pressure, the mixture was cooled to 180°C. 73 g of adipic acid, 135 g of dodecenyl succinic anhydride, and 193 g of trimellitic anhydride were added. The mixture was heated to 220°C at a rate of 10°C / hr. The pressure inside the flask was then reduced and the reaction was carried out at 10 kPa until the desired softening point was reached to obtain resin B-1. The physical properties are shown in Table 1.

[0099] Manufacturing example A3 (Manufacturing of resin A-2) A four-necked flask equipped with a nitrogen inlet tube, dehydration tube, stirrer, and thermocouple was purged with nitrogen. 3558 g of bisphenol A propylene oxide (2.2) adduct, 1416 g of bisphenol A ethylene oxide (2.2) adduct, 1229 g of terephthalic acid, 1518 g of dodecenyl succinic anhydride, and 40 g of di(2-ethylhexanoate)tin(II) were added. Under a nitrogen atmosphere, the mixture was heated to 230°C with stirring and held at 230°C for 6 hours. After that, the pressure inside the flask was further reduced to 8.3 kPa and held for 1 hour. Subsequently, the mixture was cooled to 215°C to return to atmospheric pressure. 279 g of trimellitic anhydride was added, and the mixture was held at 215°C for 1 hour. After that, the pressure inside the flask was further reduced to 8.3 kPa and held for 3 hours to obtain resin A-2. The physical properties are shown in Table 1.

[0100] Manufacturing example A4 (Manufacturing of resin D-1) Resin D-1 was obtained in the same manner as in manufacturing example A1, except that the raw material composition was changed as shown in Table 1. The physical properties are shown in Table 1.

[0101] [Table 1]

[0102] [Manufacturing of crystalline polyester resin] Manufacturing example C1 (Manufacturing of resin C-1) A 10 L four-necked flask equipped with a nitrogen inlet tube, dehydration tube, stirrer, and thermocouple was purged with nitrogen. 3416 g of 1,10-decanediol and 4084 g of sebacic acid were added, and the mixture was heated to 135°C while stirring. After holding at 135°C for 3 hours, the temperature was raised from 135°C to 200°C over 10 hours. Subsequently, 23 g of tin(II) di(2-ethylhexanoate) was added, and the mixture was held at 200°C for another hour. The pressure inside the flask was then reduced to 8.3 kPa and held under reduced pressure for 1 hour to obtain resin C-1. The physical properties are shown in Table 2.

[0103] [Table 2]

[0104] [Manufacturing of resin particle dispersions] Manufacturing Example X1 (Manufacturing of Resin Particle Dispersion X-1) In a 3L container equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen inlet tube, 210g of resin A-1, 90g of resin C-1, and 360g of methyl ethyl ketone were placed, and the resins were dissolved at 73°C for 2 hours. To the resulting solution, a 5% by mass aqueous sodium hydroxide solution was added to achieve a degree of neutralization of 60 mol% relative to the acid value of the resin, and the mixture was stirred for 30 minutes. Next, while maintaining the temperature at 73°C, 600 g of deionized water was added over 60 minutes while stirring at 280 r / min (peripheral speed 88 m / min) to induce phase inversion emulsification. While continuing to maintain the temperature at 73°C, methyl ethyl ketone was removed under reduced pressure to obtain an aqueous dispersion. Subsequently, the aqueous dispersion was cooled to 30°C while stirring at 280 r / min (peripheral speed 88 m / min), and then deionized water was added to achieve a solid content concentration of 20% by mass to obtain resin particle dispersion X-1. The median particle size D of the obtained resin particles... 50 The corresponding CV values ​​are shown in Table 3.

[0105] Manufacturing Example X2 (Manufacturing of Resin Particle Dispersion X-2) In a 3L container equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen inlet tube, 300g of resin A-2, 360g of methyl ethyl ketone, and 59g of deionized water were placed, and the resin was dissolved at 73°C for 2 hours. To the resulting solution, a 5% by mass aqueous sodium hydroxide solution was added to achieve a degree of neutralization of 60 mol% relative to the acid value of the resin, and the mixture was stirred for 30 minutes. Next, while maintaining the temperature at 73°C, 600 g of deionized water was added over 60 minutes while stirring at 280 r / min (circumferential speed 88 m / min) to induce phase inversion emulsification. While continuing to maintain the temperature at 73°C, methyl ethyl ketone was removed under reduced pressure to obtain an aqueous dispersion. Then, the aqueous dispersion was cooled to 30°C while stirring at 280 r / min (circumferential speed 63 m / min), and deionized water was added to achieve a solid content concentration of 20% by mass to obtain resin particle dispersion X-2. The obtained resin particle medium particle size D 50 The corresponding CV values ​​are shown in Table 3.

[0106] Manufacturing Example Y1 (Manufacturing of resin particle dispersion Y-1) In a 3L container equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen inlet tube, 300g of resin B-1 and 360g of methyl ethyl ketone were placed, and the resin was dissolved at 40°C for 2 hours. To the resulting solution, a 5% by mass aqueous sodium hydroxide solution was added to achieve a degree of neutralization of 60 mol% relative to the acid value of the resin, and the mixture was stirred for 30 minutes. Next, while maintaining the temperature at 40°C, 600 g of deionized water was added over 60 minutes while stirring at 280 r / min (peripheral speed 88 m / min) to induce phase inversion emulsification. The temperature was raised to 73°C, and methyl ethyl ketone was removed under reduced pressure to obtain an aqueous dispersion. Subsequently, the aqueous dispersion was cooled to 30°C while stirring at 280 r / min (peripheral speed 88 m / min), and then deionized water was added to obtain resin particle dispersion Y-1 by reducing the solid content concentration to 20% by mass. The median particle size D of the obtained resin particles 50 The corresponding CV values ​​are shown in Table 3.

[0107] Manufacturing Example Z1 (Manufacturing of Resin Particle Dispersion Z-1) In a 3L container equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen inlet tube, 200g of resin D-1 and 200g of methyl ethyl ketone were placed, and the resin was dissolved at 73°C for 2 hours. To the resulting solution, a 5% by mass aqueous sodium hydroxide solution was added to achieve a degree of neutralization of 60 mol% relative to the acid value of resin D-1, and the mixture was stirred for 30 minutes. Next, while maintaining the temperature at 73°C, 700 g of deionized water was added over 50 minutes while stirring at 280 r / min (circumferential speed 88 m / min) to induce phase inversion emulsification. While continuing to maintain the temperature at 73°C, methyl ethyl ketone was removed under reduced pressure to obtain an aqueous dispersion. Then, while stirring at 280 r / min (circumferential speed 88 m / min), the aqueous dispersion was cooled to 30°C, and deionized water was added to achieve a solid content concentration of 20% by mass to obtain resin particle dispersion Z-1. The median particle size D of the obtained resin particles... 50 The particle size was 0.09 μm, and the CV value was 23%.

[0108] [Table 3]

[0109] [Manufacturing of mold release agent particle dispersion] Manufacturing Example W1 (Manufacturing of Release Agent Particle Dispersion W-1) In a 1L beaker, 120g of deionized water, 86g of resin particle dispersion Z-1, and 40g of paraffin wax "HNP-9" (manufactured by Nippon Seiro Co., Ltd., melting point 75°C) were added. The mixture was melted while maintaining a temperature of 90-95°C and stirred 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 90-95°C, and then cooled to room temperature (20°C). Deionized water was added to adjust the solid content concentration to 20% by mass to obtain release agent particle dispersion W-1. The median particle size D of the release agent particles in the dispersion was... 50 The particle size was 0.47 μm, and the CV value was 27%.

[0110] Manufacturing Example W2 (Manufacturing of Release Agent Particle Dispersion W-2) Release agent particle dispersion W-2 was obtained in the same manner as in production example W1, except that the 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 size D of the release agent particles in the dispersion. 50 The particle size was 0.45 μm, and the CV value was 28%.

[0111] [Production of addition polymers] Manufacturing Example E1 (Synthesis of Addition Polymer E-1) 16 parts by mass of methacrylic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 44 parts by mass of styrene (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 30 parts by mass of styrene macromonomer "AS-6S" (manufactured by Toagosei Co., Ltd., number average molecular weight 6,000, solids content 50%) (15 parts by mass as solids), and 25 parts by mass of methoxypolyethylene glycol methacrylate "Bremmer PME-200" (NOF Corporation) were mixed to prepare 115 parts by mass of monomer mixture. In a reaction vessel, 18 parts by mass of methyl ethyl ketone, 0.03 parts by mass of 2-mercaptoethanol as a chain transfer agent, and 10% (11.5 parts by mass) of the monomer mixture were added and mixed, and the vessel was thoroughly purged with nitrogen gas. Meanwhile, the remaining 90% (103.5 parts by mass) of the monomer mixture was mixed with 0.27 parts by mass of the chain transfer agent, 42 parts by mass of methyl ethyl ketone, and 3 parts by mass of the polymerization initiator 2,2'-azobis(2,4-dimethylvaleronitrile) "V-65" (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.). This mixture was placed in a dropping funnel, and under a nitrogen atmosphere, the mixture in the reaction vessel was heated to 75°C while stirring, and the mixture in the dropping funnel was added dropwise over 3 hours. After 2 hours at 75°C following the completion of the dropwise addition, a solution of 3 parts by mass of the polymerization initiator dissolved in 5 parts by mass of methyl ethyl ketone was added, and the mixture was further aged at 75°C for 2 hours and then at 80°C for 2 hours. Subsequently, the methyl ethyl ketone was removed by distillation under reduced pressure to obtain addition polymer E-1. The weight-average molecular weight of the obtained addition polymer is shown in Table 4.

[0112] [Table 4]

[0113] [Manufacturing of colorant particle dispersion] Manufacturing Example F1 (Manufacturing of Colorant Particle Dispersion F-1) In a 5L container equipped with a stirrer with a disperser blade, reflux condenser, dropping funnel, thermometer, and nitrogen inlet tube, 75g of addition polymer E-1 was dissolved in 620g of methyl ethyl ketone. Then, 96g of 5% by mass aqueous sodium hydroxide solution and 942g of deionized water were added as neutralizing agents, and the mixture was stirred with the disperser blade at 20°C for 10 minutes. Subsequently, 300g of copper phthalocyanine pigment "ECB-301" (manufactured by Dainichi Seika Kogyo Co., Ltd., pigment blue 15:3) was added, and the mixture was stirred with the disperser blade at 6400rpm at 20°C for 2 hours. After that, the mixture was passed through a 200-mesh filter and subjected to 15 passes at a pressure of 150MPa using a homogenizer "Microfluidizer M-110EH" (manufactured by Microfluidics). The resulting dispersion was stirred and the methyl ethyl ketone and some water were removed under reduced pressure at 70°C. Subsequently, the mixture was passed through a 200-mesh filter, and deionized water was added to obtain a colorant particle dispersion F-1 with a solid content concentration of 20% by mass. The median particle size D of the colorant particles in the dispersion was then determined. 50 The particle size was 0.12 μm, and the CV value was 21%.

[0114] [Toner manufacturing] Manufacturing Example 1 (Preparation of Toner Master Particle 1) In a 3L four-necked flask equipped with a dewatering tube, a stirrer, and a thermocouple, 500g of resin particle dispersion X-1, 35g of mold release agent particle dispersion W-1, 35g of mold release agent particle dispersion W-2, 63g of coloring agent particle dispersion F-1, 10g of a 10% by mass aqueous solution of polyoxyethylene (50) lauryl ether "Emulgen 150" (manufactured by Kao Corporation, nonionic surfactant), and 10g of a 15% by mass aqueous solution of sodium dodecylbenzenesulfonate "Neoperex G-15" (manufactured by Kao Corporation, anionic surfactant) were mixed at 25°C. Next, while stirring the mixture, a solution prepared by dissolving 35g of ammonium sulfate in 519g of deionized water and adding 26g of a 4.8% by mass aqueous solution of potassium hydroxide was added dropwise over 10 minutes at 25°C, and then the temperature was raised to 65°C over 2 hours to determine the volume-median particle size D of the aggregated particles.50 The mixture was maintained at 65°C until it reached a size of 5.9 μm, and a dispersion of aggregated particles 1 was obtained. Next, the dispersion of aggregated particle 1 was cooled to 59°C, and while maintaining the temperature at 59°C, 75g of resin particle dispersion Y-1 was added over 90 minutes to obtain a dispersion of aggregated particle 2, in which resin particles aggregated onto aggregated particle 1. To the dispersion of the obtained aggregated particles 2, an aqueous solution was added, which consisted of 41 g of polyoxyethylene lauryl ether sodium sulfate "Emal E-27C" (manufactured by Kao Corporation, anionic surfactant, effective concentration 27% by mass), 1396 g of deionized water, and 26 g of 0.1 mol / L sulfuric acid aqueous solution. The mixture was then heated to 75°C over 1 hour, held at 75°C for 30 minutes, and then 75 g of 0.1 mol / L sulfuric acid aqueous solution was added, followed by a further 15 minutes of holding at 75°C. After that, another 25 g of 0.1 mol / L sulfuric acid aqueous solution was added, and the mixture was held at 75°C until the circularity reached 0.970, thereby obtaining a dispersion of fused particles in which the aggregated particles had fused together. The resulting dispersion of fused particles was cooled to 30°C, the solid components were separated by suction filtration, washed with deionized water at 25°C, and vacuum dried at 30°C for 48 hours to obtain toner matrix particles 1. The physical properties of the obtained toner matrix particles 1 are shown in Table 5.

[0115] Manufacturing Examples 2 and 3 (Preparation of toner matrix particles 2 and 3) Toner matrix particles 2 and 3 were prepared in the same manner as in Manufacturing Example 1, except that the circularity during the fusion process was changed as shown in Table 5. The physical properties of the obtained toner matrix particles 2 and 3 are shown in Table 5.

[0116] Manufacturing Example 4 (Preparation of Toner Maturity Particles 4) In a 3L four-necked flask equipped with a dewatering tube, a stirrer, and a thermocouple, 500g of resin particle dispersion X-2, 84g of mold release agent particle dispersion W-1, 72g of coloring agent particle dispersion F-1, 15g of a 10% by mass aqueous solution of polyoxyethylene (50) lauryl ether "Emulgen 150" (manufactured by Kao Corporation, nonionic surfactant), and 17g of a 15% by mass aqueous solution of sodium dodecylbenzenesulfonate "Neoperex G-15" (manufactured by Kao Corporation, anionic surfactant) were mixed at a temperature of 25°C. Next, while stirring the mixture, a solution prepared by dissolving 40g of ammonium sulfate in 568g of deionized water and adding a 4.8% by mass aqueous solution of potassium hydroxide to adjust the pH to 8.6 was added dropwise over 10 minutes at 25°C, and the temperature was raised to 63°C over 2 hours to determine the volume-median particle size D of the aggregated particles. 50 The mixture was maintained at 63°C until it reached a size of 5.9 μm, and a dispersion of aggregated particles 3 was obtained. Next, the dispersion of aggregated particles 3 was cooled to 59°C, and while maintaining the temperature at 59°C, 75g of resin particle dispersion Y-1 was added over 90 minutes to obtain a dispersion of aggregated particles 4, in which resin particles aggregated onto aggregated particles 3. To the dispersion of the obtained aggregated particles 4, an aqueous solution was added, which consisted of 48 g of polyoxyethylene lauryl ether sodium sulfate "Emal E-27C" (manufactured by Kao Corporation, anionic surfactant, effective concentration 27% by mass), 600 g of deionized water, and 50 g of 0.1 mol / L sulfuric acid aqueous solution. The mixture was then heated to 75°C over 1 hour, held at 75°C for 30 minutes, and then 10 g of 0.1 mol / L sulfuric acid aqueous solution was added, followed by a further 15 minutes of holding at 75°C. After that, another 10 g of 0.1 mol / L sulfuric acid aqueous solution was added, and the mixture was held at 75°C until the circularity reached 0.970, thereby obtaining a dispersion of fused particles in which the aggregated particles had fused together. The resulting dispersion of fused particles was cooled to 30°C, the solid components were separated by suction filtration, washed with deionized water at 25°C, and vacuum dried at 30°C for 48 hours to obtain toner matrix particles 4. The physical properties of the obtained toner matrix particles 4 are shown in Table 5.

[0117] Example 1 (Preparation of Toner 1) Toner 1 was obtained by mixing 100 parts by mass of toner matrix particles 1 with 6.4 parts by mass of hydrophobic large-particle silica "RY50" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic treatment agent: polydimethylsiloxane, particle size calculated from specific surface area: 119 nm) and 0.5 parts by mass of hydrophobic small-particle silica "R972" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic treatment agent: dimethyldichlorosilane, particle size calculated from specific surface area: 25 nm) in a Henschel mixer and stirring, then passing the mixture through a 150-mesh sieve. The evaluation results of the obtained toner 1 are shown in Table 5.

[0118] Examples 2-5, 8, 10, 11 (Preparation of toners 2-5, 8, 10, 11) Toners 2-5 were prepared in the same manner as in Example 1, except that the type and amount of external additives used were changed as shown in Table 5. The evaluation results of the obtained toners are shown in Table 5.

[0119] Example 6 (Preparation of Toner 6) To 100 parts by mass of toner matrix particles 2, 6.4 parts by mass of hydrophobic large-particle silica "RY50" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic treatment agent: polydimethylsiloxane, particle size calculated from specific surface area: 119 nm) and 0.5 parts by mass of hydrophobic small-particle silica "R972" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic treatment agent: dimethyldichlorosilane, particle size calculated from specific surface area: 25 nm) were added to a Henschel mixer and stirred. The mixture was then passed through a 150-mesh sieve to obtain toner 6. The evaluation results of the obtained toner 6 are shown in Table 5.

[0120] Example 7 (Preparation of Toner 7) To 100 parts by mass of toner matrix particles 3, 6.4 parts by mass of hydrophobic large-particle silica "RY50" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic treatment agent: polydimethylsiloxane, particle size calculated from specific surface area: 119 nm) and 0.5 parts by mass of hydrophobic small-particle silica "R972" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic treatment agent: dimethyldichlorosilane, particle size calculated from specific surface area: 25 nm) were added to a Henschel mixer and stirred. The mixture was then passed through a 150-mesh sieve to obtain toner 7. The evaluation results of the obtained toner 7 are shown in Table 5.

[0121] Example 9 (Preparation of Toner 9) To 100 parts by mass of toner matrix particles 4, 6.4 parts by mass of hydrophobic large-particle silica "RY50" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic treatment agent: polydimethylsiloxane, particle size calculated from specific surface area: 119 nm) and 0.5 parts by mass of hydrophobic small-particle silica "R972" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic treatment agent: dimethyldichlorosilane, particle size calculated from specific surface area: 25 nm) were added to a Henschel mixer and stirred. The mixture was then passed through a 150-mesh sieve to obtain toner 9. The evaluation results of the obtained toner 9 are shown in Table 5.

[0122] Comparative Examples 1 and 2 (Preparation of Toners 14 and 15) Toners 14 and 15 were prepared in the same manner as in Example 1, except that the type and amount of external additives used were changed as shown in Table 5. The evaluation results of the obtained toners are shown in Table 5.

[0123] [Table 5]

[0124] The results from the examples and comparative examples show that using the electrostatic image developing toner of the present invention suppresses the occurrence of fogging and furthermore, the image density of the resulting images is highly stable. In Example 8, which had charged particles, fogging was more suppressed. In Comparative Example 1, where the mass ratio of large-particle-sized silica particles to small-particle-sized silica particles was less than 7, fogging occurred and the conveying volume decreased. In Comparative Example 2, where the mass ratio of the additive rate exceeded 18, toner leakage occurred.

Claims

1. Toner base particles having a circularity of 0.965 or more, small-diameter silica particles having a particle size of 10 nm or more and 30 nm or less, calculated from the specific surface area; Large-diameter silica particles having a particle size of 70 nm or more and 190 nm or less, calculated from the specific surface area, are externally added; the mass ratio of the amount of the large silica particles to the amount of the small silica particles (large silica particles / small silica particles) is 7 or more and 18 or less; Toner for developing electrostatic images.

2. 2. The toner for developing electrostatic images according to claim 1, wherein the amount of the small-diameter silica particles added is 0.4 parts by mass or more and 1.2 parts by mass or less, and the amount of the large-diameter silica particles added is 5 parts by mass or more and 18 parts by mass or less, relative to 100 parts by mass of the toner base particles.

3. 3. The toner for developing electrostatic images according to claim 1, wherein the circularity of the toner base particles is 0.995 or less.

4. 4. The toner for developing electrostatic images according to claim 1, wherein the toner base particles contain a polyester resin as a binder resin.

5. 5. The electrostatic image developing toner according to claim 1, wherein the toner base particles contain a crystalline polyester resin and an amorphous polyester resin A as binder resins.

6. 6. The toner for developing electrostatic images according to claim 5, wherein the amorphous polyester resin A comprises a polyester resin segment which is a polycondensate of an alcohol component and a carboxylic acid component, and an addition polymerization resin segment which is an addition polymerization product of raw material monomers containing a styrene compound.

7. 7. The toner for developing electrostatic images according to claim 1, wherein the small silica particles and the large silica particles are hydrophobic silica particles.