JP7118680B2 - toner - Google Patents

Description

The present invention relates to toners used in image forming methods such as electrophotography.

Electrophotographic image forming apparatuses are required to have longer life, higher speed, energy saving, and miniaturization, and in order to meet these demands, toners are also required to further improve various performances. ing. In particular, toners are required to have further improved quality stability from the viewpoint of longer life and higher speed.
In order to improve the durability, it is conceivable to reduce the load from the outside of the toner particles. Specifically, it is conceivable to improve the surface strength of the toner particles and suppress deterioration due to rubbing against a developing roller and a regulating blade, which are members of the developing device.
In terms of charging stability, means for suppressing toner deterioration, charge build-up due to excessive rubbing with members, and charging failure can be considered. Specifically, it is conceivable to use an external additive or a charge control agent having appropriate charge leak property and charge rise property.
In Patent Document 1, the presence of a resin having a characteristic ionic functional group in the toner particles stabilizes the chargeability, improves the surface strength of the toner particles, and suppresses the embedding of external additives. is stated.
Patent Literature 2 describes that the use of strontium titanate particles, which is one of fine metal titanate particles, as an external additive results in less change in chargeability and more stability than silica.

JP 2016-66049 A JP 2015-137208 A JP 2017-44982 A

Hidetoshi Tsuchida, and three others, "Chemical Structure and Static Charge of Polymers," Kogyo Kagaku Zasshi, 1966, Vol. 69, No. 10, p. 1978-1983 "A survey of Hammett substitute constants and resonance and field parameters" Chemical Reviews 1991, Vol. 91, p. 165-195 "Linear free energy relations. V. Triboelectric charging of organic solids" Journal of the American Chemical Society 1975, Vol. 97, p. 3832-3833

The resin disclosed in Patent Document 1 can improve the surface strength of toner particles in addition to imparting high chargeability, but the fixing efficiency of the external additive in the external addition process may decrease. As a result, aggregates are likely to be formed as the frequency of collisions between the external additives increases during the external addition step, and uneven adhesion between the aggregates and the dispersion is likely to occur. As a result, the amount of the external additive released as aggregates increases during durability, and contamination of the charging roller that contacts the surface of the photoreceptor and charges the photoreceptor due to the free external additive that slips through the cleaning tends to worsen. Therefore, in order to further improve the durability, it is required to suppress uneven adhesion while maintaining the inherent effects of the external additive, such as stabilization of charging, as described in Patent Document 2. Patent Document 3 and Non-Patent Documents 1 to 3 will be described later.
An object of the present invention is to provide excellent durability while preventing contamination of the charging roller by improving the durability of toner particles and suppressing uneven fixation of external additives even when used for a long period of time, and furthermore, it is not dependent on the environment. An object of the present invention is to provide a toner exhibiting charging stability.

According to the present invention, toner particles containing a binder resin, a colorant and a charge control resin;
Metal titanate fine particles present on the surface of the toner particles ;
A toner having
The charge control resin has a structure represented by formula (1) as an ionic functional group (more specifically, represented by formula (6), (8), (9) or (10) in the examples). is a polymer of polymerizable monomers) ,

（式（１）中、Ｒ¹は、炭素数１以上１８以下のアルキル基、または、炭素数１以上１８以下のアルコキシル基を示し、ｎは０以上３以下の整数を示し、ｎが２または３の場合、Ｒ¹はそれぞれ独立して選択でき、＊は重合体における結合部位である。）
該チタン酸金属微粒子の一次粒子の個数平均粒径が、１０ｎｍ以上１４０ｎｍ以下であり、
該チタン酸金属微粒子の表面が、下記式（２）で示される部分構造ａを有し、
Ｒ²－Ｓｉ－Ｏ_3/2 式（２）
（式（２）中、Ｒ²は、末端にハメットの置換基定数σ_m（メタ）が０．２５以上である置換基を持つ官能基である。）
Ｘ線光電子分光法（ＥＳＣＡ）を用いて測定される、該チタン酸金属微粒子の表面における該部分構造ａの存在割合が、０．１１０以上０．２２０以下である、
ことを特徴とするトナーに関する。

(In formula (1), R ¹ represents an alkyl group having 1 to 18 carbon atoms or an alkoxyl group having 1 to 18 carbon atoms, n represents an integer of 0 to 3, and n is 2 or In the case of 3, each R ¹ can be selected independently and * is the binding site in the polymer.)
the primary particles of the metal titanate fine particles have a number average particle size of 10 nm or more and 140 nm or less;
The surface of the metal titanate fine particles has a partial structure a represented by the following formula (2),
R ² —Si—O _3/2 formula (2)
(In formula (2), R ² is a functional group having a substituent at its terminal with Hammett's substituent constant σ _m (meta) of 0.25 or more.)
The existence ratio of the partial structure a on the surface of the metal titanate fine particle measured by X-ray photoelectron spectroscopy (ESCA) is 0.110 or more and 0.220 or less .
The present invention relates to a toner characterized by:

According to the present invention, it is possible to prevent contamination of the charging roller by improving durability of toner particles and suppressing non-uniform fixation of external additives even in long-term durable use. It is to provide a toner that

Details of the invention are described below.

A toner comprising toner particles containing a binder resin, a colorant and a charge control resin, and metal titanate fine particles present on the surfaces of the toner particles,
The charge control resin has a structure represented by formula (1) as an ionic functional group,

（式（１）中、Ｒ¹は、炭素数１以上１８以下のアルキル基、または、炭素数１以上１８以下のアルコキシル基を示し、ｎは０以上３以下の整数を示し、ｎが２または３の場合、Ｒ¹はそれぞれ独立して選択でき、＊は重合体における結合部位である。）

(In formula (1), R ¹ represents an alkyl group having 1 to 18 carbon atoms or an alkoxyl group having 1 to 18 carbon atoms, n represents an integer of 0 to 3, and n is 2 or In the case of 3, each R ¹ can be selected independently and * is the binding site in the polymer.)

The metal titanate fine particles are
(i) the number average particle size of the primary particles is 10 nm or more and 140 nm or less;
(ii) particles having a partial structure a represented by the following formula (2) on the surface of fine metal titanate particles,
R ² —Si—O _3/2 formula (2)
(In formula (2), R ² is a functional group having a substituent at its terminal with Hammett's substituent constant σ _m (meta) of 0.25 or more.)

The existence ratio of the partial structure a on the surface of the metal titanate fine particle measured by X-ray photoelectron spectroscopy (ESCA) is 0.110 or more and 0.220 or less. Even when used for a long time, the toner has excellent durability while preventing contamination of the charging roller by improving the durability of toner particles and suppressing uneven adhesion of external additives, and also exhibits charging stability regardless of the environment. can be provided.

As will be described later in detail, by using the charge control resin having an ionic functional group represented by the formula (1) for the toner particles, the surface strength is improved to suppress deterioration, and the deteriorated toner is fused to the regulation blade. It is possible to suppress streaks (development streaks) on the printed image that occur in . In addition, since excessive water content under high temperature and high humidity conditions can be suppressed, fogging due to poor start-up of charging when the toner is left for several days under high temperature and high humidity conditions during the durability is further suppressed. On the other hand, since the surface strength of the toner particles is improved, the charging roller that comes into contact with the surface of the photoreceptor and charges the photoreceptor is contaminated due to the loose external additive caused by the non-uniform fixation of the external additive, as described above. There is a concern that streak-like image defects (charging roller contamination streaks) may occur on the printed image.

The present inventors diligently studied means for suppressing aggregation and uneven coating of an external additive and achieving high coverage and adhesion to toner particles using a charge control resin having an ionic functional group represented by formula (1). did. As a result, the number average particle diameter of the primary particles is 10 nm or more and 140 nm or less, the titanium having a partial structure on the surface as shown in formula (2), and the existence ratio of the partial structure and the terminal substituents are controlled It was found that the use of acid metal fine particles is effective. The exact reason for this is not clear, but as described later, the partial structure represented above has a highly electron-withdrawing substituent, so it has a higher negative chargeability (hereinafter referred to as , highly negatively charged). Therefore, when the metal titanate fine particles are subjected to a highly negatively charged surface treatment having the partial structure described above, the electrostatic repulsion between the metal titanate fine particles increases, suppressing agglomeration, thereby promoting uniform coating and fixing. It is considered that the unevenness could be suppressed. In addition, small-diameter fine silica particles, which are often used in combination with other external additives for the purpose of improving fluidity, are generally highly negatively chargeable. Even when silica having a small particle size is added to the toner of the present invention, the high electrostatic repulsive force suppresses aggregation of the metal titanate fine particles and the silica having a small particle size, thereby suppressing uneven fixation. As a result, the amount of free external additive can be reduced, and contamination of the charging roller can be suppressed.

In Patent Document 3, for example, if titanium oxide, which has been conventionally known as a medium-resistance material like metal titanate fine particles, is simply subjected to a surface treatment with a high negative chargeability, the charge rising property is improved, but there are restrictions under low temperature and low humidity conditions. He says the problem is getting worse. Insufficient regulation is a phenomenon in which excessive negative charging (charge-up) causes the toner, which has been left on the developing roller as undeveloped toner, to be unable to be regulated by the regulating member.

In the present invention, metal titanate fine particles, which have medium resistance and are more easily positively charged than conventional silica or titanium oxide (hereinafter referred to as positive chargeability), are used as the substrate, and partial structure a represented by formula (2) is used. By controlling the surface treatment state of the metal titanate fine particles within an appropriate range of the existence ratio, it was possible to obtain the effect of suppressing uneven adhesion while suppressing charge-up. Furthermore, the charge transfer between the toner particles was improved, and the charging rising property was improved.

The metal titanate fine particles will be described in more detail below.

When surface treatment is applied to external additives, etc., the effect of the surface layer structure, especially the side chains, is greater than that of the main chain, and the end effect is particularly large. It is known that when negatively charged and electron-donating, it becomes positively charged (see Non-Patent Document 1). Therefore, when a structure is formed on the surface layer of metal titanate fine particles by silane coupling treatment, it was thought that the chargeability of the metal titanate particles could be controlled by the functional groups of the side chains. There is Hammett's rule as an index of electron withdrawing properties and electron donating properties of substituents of functional groups. _Hammett 's rule is an empirical rule that shows the influence of substituents on reactions and equilibria of benzene derivatives. See Non-Patent Document 2). It is also known that there is a linear relationship between Hammett's substituent constant σ _m and the logarithm of the charge amount (see Non-Patent Document 3). Based on the above, it was considered that forming a partial structure having a functional group with a large value of σ _m that is electron-attracting on the surface layer of the metal titanate particles would provide an appropriate high negative chargeability.

As a result of extensive studies, the present inventors found that in the partial structure represented by formula (2), in the case of a functional group having a Hammett's substituent constant σ _m of the terminal functional group of 0.25 or more, an appropriately high negative It was found to have chargeability. Functional groups having a Hammett's substituent constant of 0.25 or more include CF ₃ , C ₆ F ₅ , NCO, CCl ₃ , NO ₂ and COOH. In the case of a functional group having a Hammett's substituent constant of 0.40 or more, the negative chargeability was further improved. Furthermore, when the terminal functional group is CF ₃ , the effect of increasing the negative chargeability due to the intrusion of adsorbed water, which will be described later, is greatly obtained.

Next, with the aim of suppressing toner charge-up while maintaining the high negative chargeability, the maintenance of the toner chargeability control function was examined. As a result, by partially arranging the partial structure a represented by the formula (2) in the surface layer of the metal titanate fine particles so that the existence ratio is 0.110 or more and 0.220 or less, high negative chargeability can be achieved. It has been found that the charge-up of the toner can be suppressed while maintaining the

Although the reason for this is not completely clear, since the partial structure a shown in formula (2) has an electron-withdrawing functional group, it suppresses the function of diffusing the charged charge, and furthermore, the metal titanate fine particle substrate is Since the surface is positively charged and can appropriately erase electric charges, it is considered that the synergistic effect of the two has a high charge control function.

It is believed that the above effect can be appropriately exhibited by controlling the surface layer existence ratio of the partial structure a represented by the formula (2) to 0.110 or more and 0.220 or less. If it is less than 0.110, the negative chargeability is insufficient, and a sufficient anti-aggregation effect cannot be obtained, resulting in uneven fixation. If it is more than 0.220, the negative chargeability is too high, making it difficult to suppress charge-up.

The surface layer existence ratio of the partial structure a represented by formula (2) can be controlled by adjusting the surface treatment method, the combination of treatment agents, the molar ratio of the raw materials of the metal titanate particles, and the production conditions.

The notation R ² —Si—O _3/2 represents a partial structure within the region enclosed by the quadrangle indicated by the dashed line in the following formulas (a) and (b), and —O ₃ . _/2 is three oxygens shared with Si atoms outside the region, as shown in (a) below, or three oxygens shared with Si atoms outside the region, as shown in (b) below. 2 and 1 oxygen shared with the strontium titanate base particles.

（＊は、チタン酸金属母粒子との結合部を表す。）

(* represents the bonding portion with the metal titanate base particles.)

The number average particle diameter of the primary particles of the metal titanate fine particles used in the present invention is 10 nm or more and 140 nm or less, preferably 10 nm or more and 80 nm or less. When the number average particle diameter is within the above range, the adhesion to toner particles becomes appropriate, and the effect as an external additive can be sufficiently exhibited. If the thickness is less than 10 nm, the coating becomes too dense and the anti-agglomeration effect is weakened. If it is larger than 140 nm, the adhesion to the toner particles is weakened, and the fixation tends to be lowered. The primary particles of the metal titanate fine particles can be controlled by adjusting the molar ratio of the raw materials of the metal titanate fine particles and the manufacturing conditions.

The metal titanate particles used in the present invention have a methanol concentration of preferably 30.0% or more and 60.0% or less when the transmittance of light with a wavelength of 780 nm is 50% in a wettability test with respect to a methanol/water mixed solvent. is. Hereinafter, the methanol concentration when the transmittance of light with a wavelength of 780 nm is 50% in the wettability test with respect to a methanol/water mixed solvent is referred to as the degree of hydrophobicity. If the degree of hydrophobicity is 30.0% or more, environmental fluctuations in the water adsorption amount can be suppressed, and changes in developability due to the environment can be suppressed. If the degree of hydrophobicity is lower than 30.0%, the negative chargeability tends to decrease especially in a high-temperature and high-humidity environment. On the other hand, if the hydrophobicity is too high, there is a tendency that the charge rising property is lowered even in a low-temperature and low-humidity environment. It was found that this is because adsorbed water cannot penetrate into the surface layer, the effect of increasing the negative chargeability cannot be obtained, and the chargeability is lowered. The wettability capable of effectively increasing the negative charging property against the penetration of the adsorbed water from the surface layer was obtained when the degree of hydrophobicity was 60.0% or less. The degree of hydrophobicity of the metal titanate particles can be controlled by adjusting the surface treatment conditions of the metal titanate particles.

When the metal other than titanium in the metal titanate fine particles used in the present invention is represented by M, the M/Ti molar ratio of the metal titanate fine particles is preferably 0.70 or more and 0.90 or less. When the M/Ti molar ratio is 0.70 or more and 0.90 or less, the proportion of Ti, which is highly reactive with the surface treatment agent, increases, and the proportion of the partial structure a represented by formula (2) is controlled. easier to do. The M/Ti molar ratio can be controlled by adjusting the molar ratio of the raw materials of the metal titanate fine particles and the manufacturing conditions.

Metal titanate particles can be produced, for example, by an atmospheric heating reaction method. At this time, it is preferable to use a mineral acid peptized hydrolyzate of a titanium compound as the titanium oxide source, and a water-soluble acidic metal compound as the metal source other than titanium. Then, it can be produced by a method of reacting the mixed solution of the raw materials while adding an alkaline aqueous solution at 60° C. or higher, followed by an acid treatment. Moreover, as a method of controlling the shape of the metal titanate particles, there is also a method of performing a dry mechanical treatment.

The normal pressure heating reaction method will be described below.

As a titanium oxide source, a hydrolyzate of a titanium compound is used. Preferably, hydrochloric acid is used to adjust the pH to 2.5 or more and 7.0 or less, more preferably 4.5 or more and 6.0 or less. As an acid, besides hydrochloric acid, nitric acid, acetic acid, or the like can be used for the acid treatment. However, the use of sulfuric acid is not preferable because strontium sulfate, which has low solubility in water, is generated.

As the alkaline aqueous solution, caustic alkali can be used, and sodium hydroxide aqueous solution is particularly preferable.

In the production method, the factors affecting the particle size of the obtained metal titanate particles include the pH when deflocculating metatitanic acid with hydrochloric acid, the mixing ratio of the titanium oxide source and the metal source other than titanium, and the initial stage of the reaction. The concentration of the titanium oxide source, the temperature at which the alkaline aqueous solution is added, the addition rate, the reaction time, the stirring conditions, and the like can be mentioned. In particular, if the reaction is stopped by rapidly lowering the temperature of the system by immersing it in ice water after the addition of the alkaline aqueous solution, the reaction can be forcibly stopped in the middle of crystal growth saturation, resulting in a wide particle size distribution. Easy to get. A wide particle size distribution can also be obtained by making the state of the reaction system nonuniform by, for example, reducing the stirring speed or changing the stirring method.

These factors can be appropriately adjusted in order to obtain metal titanate particles having the desired particle size and particle size distribution. In order to prevent the formation of carbonate during the reaction process, it is preferable to prevent contamination with carbon dioxide by, for example, conducting the reaction in a nitrogen gas atmosphere.

The mixing ratio of the titanium oxide source and the metal source M other than titanium during the reaction is preferably 0.90 or more and 1.40 or less, and 1.05 or more and 1.20 or less, in terms of the M/Ti molar ratio. is more preferable. When M/Ti (molar ratio) is less than 0.90, not only metal titanate but also unreacted titanium oxide tend to remain as reaction products. Metal sources other than titanium have relatively high solubility in water, whereas titanium oxide sources have low solubility in water. Not only acid metal but also unreacted titanium oxide tends to remain.

Next, shape control will be described. As a method for obtaining the shape of the metal titanate fine particles used in the present invention, dry mechanical treatment can be mentioned. For example, Hybridizer (manufactured by Nara Machinery Co., Ltd.), Nobilta (manufactured by Hosokawa Micron Corporation), Mechanofusion (manufactured by Hosokawa Micron Corporation), Hiflex Gral (manufactured by Earth Technica Corporation), and the like can be used. By treating the metal titanate fine particles with these apparatuses, the surface treatability of the metal titanate can be improved.

When the shape of the metal titanate fine particles is controlled by mechanical treatment, fine powder of the metal titanate fine particles may be generated. In order to remove fine powder, it is preferable to carry out an acid treatment. In the acid treatment, it is preferable to adjust the pH to 0.1 or more and 5.0 or less using hydrochloric acid. As an acid, besides hydrochloric acid, nitric acid, acetic acid, or the like can be used for the acid treatment. The mechanical treatment for controlling the shape of the metal titanate fine particles is preferably carried out before the surface treatment of the metal titanate fine particles.

The surface treatment of the metal titanate fine particles of the present invention will be described. In order to obtain the partial structure a represented by formula (2) on the surface of the metal titanate fine particles used in the present invention, surface coating with a silane coupling agent can be used. A fluoroalkylsilane coupling agent, an isocyanate silane coupling agent, and the like can be used as the silane coupling agent. The treatment method includes a wet method in which a surface treatment agent to be treated is dissolved and dispersed in a solvent, metal titanate fine particles are added therein, and the solvent is removed while stirring. Another example is a dry method in which a coupling agent, a fatty acid metal salt, and metal titanate fine particles are directly mixed and treated while being stirred.

As a method for obtaining the abundance ratio of the partial structure a represented by formula (2), there is a method of performing treatment in combination with other silane coupling agents, and a method of surface coating with a hydrophobizing agent such as silicone oil, followed by treatment. There is a method for doing this. By mixing and stirring multiple types of silane coupling agents, the bonding between the coupling agents progresses, making it easier to process the surface layer of the metal titanate fine particles into an island shape. It is more desirable as a treatment method for controlling the abundance ratio within an appropriate range. As a silane coupling agent to be combined, it is more preferable to use an alkylsilane coupling agent or the like in order to obtain the partial structure b represented by the formula (3) on the surface of the metal titanate fine particles. By obtaining the partial structure b represented by the formula (3) on the surface of the metal titanate, the effect of suppressing excessive negative charging can be further improved.
R ³ —Si—O ^3/2 Formula (3)
(In formula (3), R ³ is an alkyl group.)

As the metal source M, strontium is more preferable from the viewpoint of appropriate reactivity during particle size control and chargeability as a metal titanate fine particle substrate.

The amount of metal titanate particles used in the present invention to be added is 0.05 per 100.0 parts by mass of toner particles, as a range in which proper adhesion to toner particles and an expected effect as an external additive can be exhibited without adverse effects. More than 2.00 mass parts or less is preferable. When it is 0.05 parts by mass or more, the coating is sufficient and the aggregation suppressing effect is easily obtained, and when it is 2.00 parts by mass or less, the particles are not densely covered due to excessive coating, and the effect of suppressing aggregation is reduced. do not have.

Next, the toner particles of the present invention will be described in detail.

The toner particles of the present invention contain a charge control resin having an ionic functional group as represented by formula (1).

（式（１）中、Ｒ¹は、炭素数１以上１８以下のアルキル基、または、炭素数１以上１８以下のアルコキシル基を示し、ｎは０以上３以下の整数を示し、ｎが２または３の場合、Ｒ¹はそれぞれ独立して選択でき、＊は重合体における結合部位である。）

(In formula (1), R ¹ represents an alkyl group having 1 to 18 carbon atoms or an alkoxyl group having 1 to 18 carbon atoms, n represents an integer of 0 to 3, and n is 2 or In the case of 3, each R ¹ can be selected independently and * is the binding site in the polymer.)

By using the above charge control resin, the surface strength of the toner particles can be improved. Although the reason for this is not clear, in the polymer unit forming the charge control resin, the ionic functional group of the formula (1) increases the bonding strength due to the hydrogen bonding interaction between molecules and between molecules. It is believed that the presence of the resin in the vicinity of the surface of the toner particles improves the surface strength. In addition, the charge control resin having the ionic functional group of formula (1) can suppress moisture adsorption especially under high temperature and high humidity conditions. It is believed that the reason for this is that the ionic functional group of formula (1) suppresses acid dissociation and thus suppresses moisture adsorption. As a result, as described above, it is possible to suppress the decrease in charge due to excessive water content under high temperature and high humidity conditions, and to maintain high chargeability even when the metal titanate fine particles of the present invention are used in combination.

As the resin having an ionic functional group, any resin having the ionic functional group of the formula (1) may be used. For example, it is preferable to polymerize vinyl salicylic acid or 1-vinyl phthalate.

Examples of alkyl groups for R ¹ include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, s-butyl group, t-butyl group, etc. Examples of alkoxy groups include methoxy groups, ethoxy groups, propoxy groups, and the like. There are no particular restrictions on the main chain structure of the polymer. Examples thereof include vinyl-based polymers, polyester-based polymers, polyamide-based polymers, polyurethane-based polymers, and polyether-based polymers. In addition, hybrid type polymers in which two or more of these are combined are also included. Among those mentioned here, the vinyl-based polymer is preferable in consideration of the adhesion to the toner base particles.

Preferably, the charge control resin is a polymer (having a monovalent group) having a site represented by the following formula (4).

（Ｒ⁷は、炭素数１以上１８以下のアルキル基、または、炭素数１以上１８以下のアルコキシル基を表し示し、Ｒ⁸は、水素原子、ヒドロキシル基、炭素数１以上１８以下のアルキル基、または、炭素数１以上１８以下のアルコキシル基を示し、ｇは１以上３以下の整数を示し、ｈは０以上３以下の整数を示し、ｈが２または３の場合、Ｒ⁷はそれぞれ独立して選択でき、＊は重合体における結合部位である。）

(R ⁷ represents an alkyl group having 1 to 18 carbon atoms or an alkoxyl group having 1 to 18 carbon atoms, R ⁸ represents a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 18 carbon atoms, Alternatively, an alkoxyl group having 1 to 18 carbon atoms, g is an integer of 1 to 3, h is an integer of 0 to 3, and when h is 2 or 3, each R ⁷ is independently and * is the binding site in the polymer.)

Further, when a polymer constituting the charge control resin and containing the ionic functional group (1) is referred to as a polymer C, the monovalent group c represented by the ionic functional group (1) contained in the polymer C is included. The amount is preferably 50 μmol/g or more and 1000 μmol/g or less. By making it 50 μmol/g or more, good chargeability and durability can be exhibited. Moreover, charge-up can be suppressed by setting the amount to 1000 μmol/g or less.

The content of the monovalent group c represented by the ionic functional group (1) in the polymer C can be determined by the method described below. First, by titrating the polymer C by the method described later, the acid value of the polymer C is quantified, and the carboxy group derived from the monovalent group c represented by the ionic functional group (1) possessed by the polymer C Calculate the amount of Based on this, the content (μmol/g) of the monovalent group c represented by the structural formula (1) in the polymer C can be calculated. In addition, when the polymer C has a carboxy group at a site other than the monovalent group c represented by the structural formula (1), when the polymer C is produced, 1 represented by the structural formula (1) The acid value of the compound (for example, polyester resin) is measured in advance immediately before the addition reaction of the functional group c. The addition amount of the monovalent group c represented by Structural Formula (1) can be calculated from the difference from the acid value of the polymer C after the addition reaction.

Further, NMR is measured, the mol ratio of each component is calculated from the integrated value derived from the characteristic chemical shift value of each monomer component, and the content (μmol / g) is calculated based on it. can.

The addition amount of the charge control resin used in the process of manufacturing the toner particles is 0.05 parts by mass with respect to 100.0 parts by mass of the binder resin as a range in which the effect of improving the surface strength and sufficient adhesion of the external additive can be obtained. It is preferable that it is more than 5.00 mass parts or less. At 0.05 parts by mass or more, the effect of improving the surface strength is sufficiently exhibited and the effect of suppressing adsorbed moisture is also increased.

The toner particles of the present invention have a binder resin, and examples of preferred polymerizable monomers that can be used as the binder resin include vinyl-based polymerizable monomers. For example styrene; styrene derivatives such as α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate. , iso-propyl acrylate, n-butyl acrylate, iso-butyl acrylate, tert-butyl acrylate, acrylic polymerizable monomers such as 2-ethylhexyl acrylate; methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, iso-propyl methacrylic polymerizable monomers such as methacrylate, n-butyl methacrylate, iso-butyl methacrylate and tert-butyl methacrylate; methylene aliphatic monocarboxylic acid esters; vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate, Vinyl esters such as vinyl benzoate and vinyl formate can be mentioned.

The average circularity of the toner particles is preferably 0.960 or more. When it is 0.960 or more, fine line reproducibility is also improved. More preferably, it is 0.970 or more.

The method of manufacturing the toner particles is not particularly limited. Examples thereof include a method of directly producing a toner in a hydrophilic medium (hereinafter also referred to as a polymerization method) such as a suspension polymerization method, an interfacial polymerization method, and a dispersion polymerization method. Further, a pulverization method may be used, and the toner obtained by the pulverization method may be thermally sphericalized. Among them, the toner produced by the suspension polymerization method is preferable because the individual particles are almost spherical and the distribution of the charge amount is relatively uniform, so that the toner has high transferability.

In the suspension polymerization method, a polymerizable monomer composition containing a polymerizable monomer that forms a binder resin, a colorant, and optionally additives such as wax is dispersed in an aqueous medium to form a polymerizable monomer composition. It is a method of producing toner particles through a granulation step of producing droplets of a monomer composition and a polymerization step of polymerizing the polymerizable monomer in the droplets.

The toner of the present invention is preferably a toner having toner particles having a core portion and a shell portion. As the resin for forming the shell portion, polyester, styrene-acrylic copolymer, styrene-methacrylic copolymer, or another resin is preferably used, and polyester resin is more preferable.

The toner particles preferably contain wax.

Wax components include paraffin wax, microcrystalline wax, petroleum waxes such as petrolatum and their derivatives, montan wax and its derivatives, hydrocarbon waxes produced by the Fischer-Tropsch process and their derivatives, polyolefin waxes such as polyethylene and polypropylene and their derivatives. Derivatives, natural waxes such as carnauba wax and candelilla wax, derivatives thereof, etc. Derivatives include oxides, block copolymers with vinyl monomers, and graft-modified products. Furthermore, higher fatty alcohols, fatty acids such as stearic acid and palmitic acid, or compounds thereof, acid amide waxes and ester waxes can also be used.

The toner particles contain a colorant. As the black colorant, carbon black, magnetic material, and yellow/magenta/cyan colorants shown below are used to give a black color.

Yellow colorants include compounds typified by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds. Specifically, the following C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 62, 73, 74, 83, 93, 94, 95, 97, 109, 110, 111, 120, 128, 129, 138, 147, 150, 151, 154, 155, 168, 180, 185, 214.

Magenta colorants include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. Specifically, the following C.I. I. Pigment Red 2, 3, 5, 6, 7, 23, 48:2, 48:3, 48:4, 57:1, 81:1, 122, 146, 166, 169, 177, 184, 185, 202, 206, 220, 221, 238, 254, 269, C.I. I. Pigment Violet 19 can be mentioned.

Cyan colorants include copper phthalocyanine compounds and their derivatives, anthraquinone compounds, basic dye lake compounds. Specifically, C.I. I. Pigment Blue 1, 7, 15, 15:1, 15:2, 15:3, 15:4, 60, 62, 66.

These colorants can be used singly or in combination and further in the form of a solid solution. Colorants are selected from the viewpoint of hue angle, chroma, brightness, light resistance, OHP transparency, and dispersibility in toner. The amount of the coloring agent to be added is preferably 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the polymerizable monomer forming the binder resin or the binder resin.

Furthermore, the toner of the present invention can be made into a magnetic toner by containing a magnetic substance as a coloring agent. Magnetic substances include iron oxides such as magnetite, hematite and ferrite, metals such as iron, cobalt and nickel, or these metals together with aluminum, copper, magnesium, tin, zinc, beryllium, calcium, manganese, selenium, titanium, Alloys with metals such as tungsten, vanadium and mixtures thereof are included.

The magnetic material is more preferably a surface-modified magnetic material. When a magnetic toner is prepared by a polymerization method, it is preferably subjected to hydrophobic treatment with a surface modifier, which is a substance that does not inhibit polymerization. Examples of such surface modifiers include silane coupling agents and titanium coupling agents. The number average particle size of these magnetic substances is preferably 2.0 μm or less, more preferably 0.1 μm or more and 0.5 μm or less. The amount contained in the toner particles is preferably 20 parts by mass or more and 200 parts by mass or less, more preferably 40 parts by mass or more and 150 parts by mass or less with respect to 100 parts by mass of the polymerizable monomer or the binder resin.

Examples of the production method for producing toner particles by a pulverization method include the following.

In the raw material mixing step, predetermined amounts of binder resin, colorant, other additives, etc. as materials constituting toner particles are weighed, blended, and mixed. Examples of the mixing device include a double-con mixer, V-type mixer, drum-type mixer, super mixer, FM mixer, Nauta mixer, and Mechanohybrid (manufactured by Nippon Coke Kogyo Co., Ltd.).

Next, the mixed materials are melt-kneaded to disperse the coloring agent and the like in the binder resin. In the melt-kneading step, a pressure kneader, a batch type kneader such as a Banbury mixer, or a continuous kneader can be used. A single-screw or twin-screw extruder is the mainstream because of its superiority in continuous production. For example, KTK type twin-screw extruder (manufactured by Kobe Steel, Ltd.), TEM type twin-screw extruder (manufactured by Toshiba Machine Co., Ltd.), PCM kneader (manufactured by Ikegai), twin-screw extruder (manufactured by KCK Corporation) , Co-Kneader (manufactured by Buss Co., Ltd.), Kneedex (manufactured by Nippon Coke Industry Co., Ltd.), and the like. Furthermore, the resin composition obtained by melt-kneading may be rolled with two rolls or the like and cooled with water or the like in the cooling step.

The cooled resin composition is then pulverized to a desired particle size in a pulverization step. In the pulverization process, for example, after coarse pulverization with a pulverizer such as a crusher, hammer mill, or feather mill, further, for example, Kryptron System (manufactured by Kawasaki Heavy Industries, Ltd.), Super Rotor (manufactured by Nisshin Engineering Co., Ltd.), Turbo · Finely pulverize with a mill (manufactured by Freund Turbo Co., Ltd.) or an air jet type pulverizer.

After that, if necessary, inertial classification method Elbow Jet (manufactured by Nittetsu Mining Co., Ltd.), centrifugal force classification method Turboplex (manufactured by Hosokawa Micron Corporation), TSP Separator (manufactured by Hosokawa Micron Corporation), Faculty (manufactured by Hosokawa Micron Corporation) The particles are classified using a classifier or a sieving machine to obtain toner particles.

Also, the toner particles may be spherical. For example, after pulverization, it is spheroidized using a hybridization system (manufactured by Nara Machinery Co., Ltd.), a mechanofusion system (manufactured by Hosokawa Micron Corporation), a faculty (manufactured by Hosokawa Micron Corporation), or a Meteor Rainbow MR Type (manufactured by Nippon Pneumatic Industry Co., Ltd.). .

A toner can be obtained by mixing toner particles with metal titanate fine particles and, if necessary, other external additives. Mixers for externally adding toner particles include FM Mixer (manufactured by Nippon Coke Kogyo Co., Ltd.), Super Mixer (manufactured by Kawata Co., Ltd.), Nobilta (manufactured by Hosokawa Micron Co., Ltd.), and Hybridizer (manufactured by Nara Machinery Co., Ltd.).

Moreover, the sieving device used for sieving coarse particles after external addition includes the following. Ultrasonic (manufactured by Koei Sangyo Co., Ltd.); Resonator Sieve, Gyro Shifter (Tokuju Kosakusho Co., Ltd.); Vibra Sonic System (manufactured by Dalton Co., Ltd.); Sonic Clean (manufactured by Sintokogyo Co.); ); Micro shifter (manufactured by Makino Sangyo Co., Ltd.).

The toner of the present invention may contain external additives other than the fine metal titanate particles. In particular, a fluidity improver may be added to improve the fluidity and chargeability of the toner.

As the fluidity improver, the following can be used. For example, finely powdered silica such as wet-processed silica and dry-processed silica, and treated silica obtained by surface-treating them with a silane compound or silicone oil can be used.

The number average particle diameter of the primary particles of the fluidity improver is preferably 5 nm or more and 30 nm or less, since high chargeability and fluidity can be imparted.

Furthermore, as the fluidity improver, treated silica fine powder obtained by hydrophobizing silica fine powder with silicone oil and/or a silane coupling agent is more preferable.

The fluidity improver preferably has a specific surface area of 30 m ² /g or more and 300 m ² /g or less by nitrogen adsorption measured by the BET method.

It is preferable to use the fluidity improver in a total amount of 0.01 parts by mass or more and 3 parts by mass or less with respect to 100 parts by mass of the toner particles.

Methods for measuring various physical properties of the toner of the present invention are described below.

When the physical properties of the metal titanate fine particles and the toner particles are measured from the toner to which the metal titanate fine particles are externally added, the metal titanate fine particles and other external additives can be separated from the toner for measurement. The toner is ultrasonically dispersed in methanol to remove metal titanate fine particles and other external additives, and allowed to stand still for 24 hours. The sedimented toner particles and the fine metal titanate particles and other external additives dispersed in the supernatant liquid are separated, recovered, and sufficiently dried to isolate the toner particles. In addition, the metal titanate microparticles can be isolated by centrifuging the supernatant.

<Number Average Particle Diameter of Primary Particles of Metal Titanate Fine Particles>
The number average particle diameter of the primary particles of the metal titanate fine particles is measured using a transmission electron microscope "JEM-2800" (JEOL Ltd.). The toner to which the metal titanate fine particles are externally added is observed, and the major diameters of the primary particles of 100 metal titanate fine particles are randomly measured in a field magnified up to 200,000 times to determine the number average particle diameter. The observation magnification is appropriately adjusted according to the size of the metal titanate fine particles.

Confirmation that the external additive is metal titanate fine particles is carried out by STEM-EDS measurement.

The measurement conditions are as follows.
JEM2800 type transmission electron microscope: accelerating voltage 200 kV
EDS detector: JED-2300T (JEOL Ltd., element area: 100 mm ² ) was used EDS analyzer: Noran System 7 (Thermo Fisher Scientific) was used.
X-ray storage rate: 10000-15000cps
Dead time: Adjust the electron dose to 20 to 30%, and perform EDS analysis (100 cumulative times or 5 minutes of measurement time).

<Identification of partial structure on the surface of metal titanate fine particles>
Identification of the partial structure on the surface of the metal titanate fine particles is performed by a time-of-flight secondary ion mass spectrometer (TOF-SIMS). Using the following equipment under the following conditions, the partial structure is identified from the fragment peak of the surface layer of the metal titanate fine particles.
・ Measuring device: TRIFT-IV (trade name, manufactured by ULVAC-PHI, Inc.)
・Primary ion: Au ³⁺
・Raster size: 100 μm×100 μm
・Neutralization electron gun: use

<Abundance ratio of partial structure a on the surface of metal titanate fine particles>
Elemental analysis of the surface of metal titanate fine particles is performed using the following equipment under the following conditions.
・ Measuring device: Quantum 2000 (trade name, manufactured by ULVAC-PHI, Inc.)
・X-ray source: monochrome Al Kα
・Xray Setting: 100μmφ (25W (15KV))
・Photoelectron extraction angle: 45 degrees ・Neutralization condition: combined use of neutralization gun and ion gun ・Analysis area: 300×200 μm
・Pass Energy: 58.70eV
・Step size: 0.125 eV
・Analysis software: Maltipak (PHI)

The surface atomic concentration (atomic %) was calculated from the measured peak intensity of each element. For all the identified partial structures, the surface atomic concentration (atomic %) that can identify the partial structure was divided by the number of atoms contained in the partial structure of the identified atoms, and the abundance on the surface of the partial structure was obtained. In addition, the abundance of the original metal titanate fine particles was defined as the atomic concentration of Ti. From the above, the abundance ratio of the partial structure a is represented by the following formula (5).
Abundance ratio of partial structure a=Abundance of partial structure a/(Abundance of partial structure a+Abundance of partial structure b+Abundance of other structure 1+...+Ti atom concentration) Equation (5)

<Molar ratio of M/Ti of metal titanate fine particles>
The content of M and Ti in the metal titanate fine particles used in the present invention can be determined by a fluorescent X-ray spectrometer. For example, using a wavelength dispersive X-ray fluorescence spectrometer Axios advanced (manufactured by PANalytical), 1 g of a sample is weighed on a cup dedicated to powder measurement recommended by PANalytical with a special film attached, and under atmospheric pressure He atmosphere. Elements from Na to U in the metal titanate fine particles are measured by the FP method. At that time, assuming that all the detected elements are oxides, their total mass is 100%, and the content of MXO and TiO ₂ with respect to the total mass (mass% ) is calculated as an oxide conversion value. After that, after obtaining M/Ti (mass ratio) excluding oxygen from the quantitative results, the atomic weight of each element is converted to M/Ti (molar ratio).

<Hydrophobicity of metal titanate fine particles>
The degree of hydrophobicity of the metal titanate fine particles was measured with a powder wettability tester "WET-100P" (manufactured by Lesca).

A fluororesin-coated spindle rotor having a length of 25 mm and a maximum barrel diameter of 8 mm was placed in a cylindrical glass container having a diameter of 5 cm and a thickness of 1.75 mm. After putting 70 ml of a water-containing methanol liquid consisting of 50% by volume of methanol and 50% by volume of water into the cylindrical glass container, 0.5 g of metal titanate fine particles was added, and the container was set in a powder wettability tester. Methanol was added to the liquid at a rate of 0.8 mL/min through the powder wettability tester while stirring at a rotation speed of 3.3 times/second using a magnetic stirrer. The transmittance was measured with light having a wavelength of 780 nm, and the value represented by the volume percentage of methanol (= (volume of methanol/volume of mixture) × 100) when the transmittance reached 50% was taken as the degree of hydrophobicity. . The initial volume ratio of methanol and water is appropriately adjusted according to the degree of hydrophobization of the sample.

<Method for Measuring Weight Average Particle Diameter (D4) of Toner Particles>
The weight average particle diameter (D4) of toner particles is calculated as follows. As a measuring device, a precision particle size distribution measuring device "Coulter Counter Multisizer 3" (registered trademark, manufactured by Beckman Coulter, Inc.) using a pore electrical resistance method equipped with a 100 μm aperture tube is used. The attached dedicated software "Beckman Coulter Multisizer 3 Version 3.51" (manufactured by Beckman Coulter, Inc.) is used for setting the measurement conditions and analyzing the measurement data. The measurement is performed with 25,000 effective measurement channels. As the electrolytic aqueous solution used for measurement, a solution obtained by dissolving special grade sodium chloride in ion-exchanged water to a concentration of about 1% by mass, for example, "ISOTON II" (manufactured by Beckman Coulter, Inc.) can be used.

Before conducting the measurement and analysis, the dedicated software was set as follows. On the "change standard measurement method (SOM)" screen of the dedicated software, set the total count number in control mode to 50000 particles, set the number of measurements to 1, and set the Kd value to "standard particle 10.0 μm" (Beckman Coulter (manufactured by Co., Ltd.) is used to set the value obtained. By pressing the "threshold/noise level measurement button", the threshold and noise level are automatically set. Also, set the current to 1600 μA, the gain to 2, the electrolyte to ISOTON II, and put a check in the “Flush aperture tube after measurement” box. On the "pulse-to-particle size conversion setting" screen of the dedicated software, set the bin interval to logarithmic particle size, the particle size bin to 256 particle size bins, and the particle size range from 2 μm to 60 μm.

A specific measuring method is as follows.
(1) About 200 ml of the electrolytic aqueous solution is placed in a 250 ml round-bottom glass beaker exclusively for Multisizer 3, set on a sample stand, and stirred with a stirrer rod counterclockwise at 24 rotations/sec. Then, remove dirt and air bubbles inside the aperture tube using the dedicated software's "Flush Aperture" function.
(2) About 30 ml of the electrolytic aqueous solution is placed in a 100 ml flat-bottom glass beaker. As a dispersant, "Contaminon N" (a 10% by mass aqueous solution of a neutral detergent for cleaning precision measuring instruments at pH 7 consisting of a nonionic surfactant, an anionic surfactant, and an organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) was used as a dispersant. ) is diluted with ion-exchanged water to about 3 times the mass, and about 0.3 ml of the diluted solution is added.
(3) Prepare an ultrasonic disperser "Ultrasonic Dispersion System Tetora 150" (manufactured by Nikkaki Bios Co., Ltd.) having an electric output of 120 W and incorporating two oscillators with an oscillation frequency of 50 kHz with a phase shift of 180 degrees. About 3.3 l of ion-exchanged water is placed in the water tank of the ultrasonic disperser, and about 2 ml of Contaminon N is added to this water tank.
(4) The beaker of (2) is set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. Then, the height position of the beaker is adjusted so that the resonance state of the liquid level of the electrolytic aqueous solution in the beaker is maximized.
(5) While the electrolytic aqueous solution in the beaker in (4) above is being irradiated with ultrasonic waves, about 10 mg of toner is added little by little to the electrolytic aqueous solution and dispersed. Then, the ultrasonic dispersion treatment is continued for another 60 seconds. In the ultrasonic dispersion, the temperature of the water in the water tank is appropriately adjusted to 10°C or higher and 40°C or lower.
(6) Using a pipette, drop the electrolytic aqueous solution of (5) in which the toner is dispersed into the round-bottomed beaker of (1) set in the sample stand, and adjust the measured concentration to about 5%. . The measurement is continued until the number of measured particles reaches 50,000.
(7) Analyze the measurement data with the dedicated software attached to the apparatus, and calculate the weight average particle size (D4). Incidentally, the weight average particle diameter (D4) is the "average diameter" on the "analysis/volume statistical value (arithmetic mean)" screen when graph/vol% is set in the dedicated software.

<Method for Measuring Circularity of Toner>
The circularity of the toner in the present invention is measured using a flow type particle image measuring apparatus "FPIA-3000" (manufactured by Sysmex Corporation) under measurement and analysis conditions during calibration work.

A specific measuring method is as follows. First, about 20 ml of ion-exchanged water, from which solid impurities have been removed in advance, is placed in a glass container. As a dispersant, "Contaminon N" (a 10% by mass aqueous solution of a neutral detergent for cleaning precision measuring instruments at pH 7 consisting of a nonionic surfactant, an anionic surfactant, and an organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) was used as a dispersant. ) is diluted with ion-exchanged water to about 3 times the mass, and about 0.2 ml of the diluted solution is added. Further, about 0.02 g of a measurement sample is added, and dispersion treatment is performed for 2 minutes using an ultrasonic disperser to obtain a dispersion liquid for measurement. At that time, the temperature of the dispersion liquid is appropriately cooled to 10° C. or higher and 40° C. or lower. As the ultrasonic disperser, a desktop ultrasonic cleaner disperser (for example, "VS-150" (manufactured by Vervoclea) with an oscillation frequency of 50 kHz and an electrical output of 150 W) is used, and a predetermined amount of Ion-exchanged water is put in, and about 2 ml of the contaminon N is added to this water tank.

For the measurement, the flow-type particle image analyzer equipped with "UPlanApro" (10x magnification, numerical aperture 0.40) was used as the objective lens, and the particle sheath "PSE-900A" (manufactured by Sysmex Corporation) was used as the sheath liquid. It was used. The dispersion prepared according to the above procedure is introduced into the flow type particle image analyzer, and 3000 toner particles are counted in the HPF measurement mode and the total count mode. Then, the binarization threshold during particle analysis is set to 85%, the analysis particle diameter is limited to a circle equivalent diameter of 1.99 μm or more and less than 39.6 μm, and the average circularity is obtained.

In the measurement, automatic focus adjustment is performed using standard latex particles (for example, "RESEARCH AND TEST PARTICLES Latex Microsphere Suspensions 5200A" manufactured by Duke Scientific diluted with deionized water) before starting the measurement. After that, it is preferable to perform focus adjustment every two hours from the start of measurement.

In the examples of the present application, a flow-type particle image analyzer with a calibration certificate issued by Sysmex Corporation was used. Except for limiting the analyzed particle size to a circle equivalent diameter of 1.99 μm or more and less than 39.6 μm, the measurement was performed under the measurement and analysis conditions when the calibration certificate was received.

<Glass transition temperature (Tg) of charge control resin>
The glass transition temperature (Tg) of the toner base particles and the resin particles is measured using a differential scanning calorimeter (DSC) M-DSC (trade name: Q2000, manufactured by TA-Instruments) according to the following procedure. Accurately weigh 3 mg of the sample to be measured. This is placed in an aluminum pan, and an empty aluminum pan is used as a reference, and the temperature is measured within the measurement temperature range of 20 to 200° C. at a temperature elevation rate of 1° C./min under normal temperature and normal humidity. Measurement is performed at a modulation amplitude of ±0.5° C. and a frequency of 1/min. A glass transition temperature (Tg:° C.) is calculated from the resulting reversing heat flow curve. The Tg is obtained by taking the central value of the intersection of the baseline before and after the endotherm and the tangent line of the curve due to the endotherm as Tg (°C).

<Acid value of charge control resin>
The acid value is mg of potassium hydroxide required to neutralize the acid contained in 1 g of sample. The acid value in the present invention is measured according to JIS K 0070-1992, and more specifically according to the following procedure.

Titration is performed using a 0.1 mol/l potassium hydroxide ethyl alcohol solution (manufactured by Kishida Chemical Co., Ltd.). The factor of the potassium hydroxide ethyl alcohol solution can be determined using a potentiometric titrator (potentiometric titrator AT-510 manufactured by Kyoto Electronics Industry Co., Ltd.). 100 ml of 0.100 mol/l hydrochloric acid is placed in a 250 ml tall beaker and titrated with the potassium hydroxide ethyl alcohol solution to determine the amount of the potassium hydroxide ethyl alcohol solution required for neutralization. The above 0.100 mol/l hydrochloric acid is prepared according to JIS K 8001-1998.

Measurement conditions for acid value measurement are shown below.
Titrator: potentiometric titrator AT-510 (manufactured by Kyoto Electronics Industry Co., Ltd.)
Electrode: Composite glass electrode double junction type (manufactured by Kyoto Electronics Industry Co., Ltd.)
Control software for titrator: AT-WIN
Titration analysis software: Tview

Titration parameters and control parameters at the time of titration are performed as follows.
Titration Parameters Titration Mode: Blank Titration Titration Mode: Total Titration Maximum Titration Volume: 20ml
Waiting time before titration: 30 seconds Titration direction: Automatic control parameter End point judgment potential: 30 dE
End point judgment potential value: 50 dE / dmL
End point detection judgment: Not set Control speed mode: Standard gain: 1
Data acquisition potential: 4 mV
Data collection titer volume: 0.1 ml

Main test;
0.100 g of a measurement sample is precisely weighed in a 250 ml tall beaker, 150 ml of a mixed solution of toluene/ethanol (3:1) is added, and dissolved over 1 hour. Titration is performed using the potassium hydroxide ethyl alcohol solution using the potentiometric titrator.

blank test;
Titration is performed in the same manner as described above except that no sample is used (that is, only a mixed solution of toluene/ethanol (3:1) is used).

The acid value is calculated by substituting the obtained result into the following formula.
A = [(CB) x f x 5.611]/S
(In the formula, A: acid value (mgKOH/g), B: added amount of potassium hydroxide ethyl alcohol solution for blank test (ml), C: added amount of potassium hydroxide ethyl alcohol solution for final test (ml), f: factor of potassium hydroxide solution, S: sample (g).)

<NMR of charge control resin>
The content of structure c contained in polymer C is determined using nuclear magnetic resonance spectroscopy (1H-NMR) [400 MHz, CDCl3, room temperature (25° C.)].
Measuring device: FT NMR device JNM-EX400 (manufactured by JEOL Ltd.)
Measurement frequency: 400MHz
Pulse condition: 5.0 μs
Frequency range: 10500Hz
Accumulated times: 64 times

The mol ratio of each monomer component is obtained from the integrated value of the obtained spectrum, and the mol % of the structure c contained in the polymer C is calculated based on this.

EXAMPLES The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited to these.

Metal titanate fine particles (strontium titanate 1 to 13, calcium titanate, magnesium titanate, potassium titanate) used as an external additive 1 to be described later were prepared as follows, and their physical properties are shown in Table 1.

<Production Example 1 of Strontium Titanate Particles>
Metatitanic acid obtained by the sulfuric acid method was deironized and bleached, then adjusted to pH 9.0 with an aqueous sodium hydroxide solution, desulfurized, neutralized to pH 5.8 with hydrochloric acid, filtered and washed with water. Water was added to the washed cake to obtain a slurry of 1.85 mol/L as TiO ₂ , and then hydrochloric acid was added to adjust the pH to 1.0 for deflocculation.

1.88 mol of metatitanic acid, which had undergone desulfurization and deflocculation, was taken as TiO ₂ and charged into a 3 L reactor. After adding 2.16 mol of an aqueous strontium chloride solution to the peptized metatitanic acid slurry so that the SrO/TiO ₂ molar ratio was 1.15, the TiO ₂ concentration was adjusted to 1.039 mol/L. Next, after heating to 90° C. while stirring and mixing, 440 mL of 10 N mol/L sodium hydroxide aqueous solution was added over 45 minutes, and then stirring was continued at 95° C. for 1 hour to complete the reaction.

The reaction slurry was cooled to 50° C., hydrochloric acid was added until the pH reached 5.0, and stirring was continued for 20 minutes. The obtained precipitate was washed by decantation, filtered and separated, and then dried in the air at 120° C. for 8 hours.

Subsequently, 300 g of the dried product was put into a dry particle compounding device (Nobilta NOB-130 manufactured by Hosokawa Micron). The treatment was performed for 10 minutes at a treatment temperature of 30° C. and a rotary treatment blade of 90 m/sec.

Further, hydrochloric acid was added to the dried product until the pH reached 0.1, and stirring was continued for 1 hour. The resulting precipitate was washed by decantation.

The slurry containing the precipitate was adjusted to 40° C. and adjusted to pH 2.5 by adding hydrochloric acid. Next, 4.6% by mass of isobutyltrimethoxysilane and 4.6% by mass of trifluoropropyltrimethoxysilane with respect to the solid content were stirred and mixed for 1 hour, and then added, and the stirring was continued for 10 hours. A 5N sodium hydroxide solution was added to adjust the pH to 6.5, and the mixture was stirred for 1 hour, filtered and washed.

<Production Example 2 of Strontium Titanate Particles>
For the strontium titanate particle production example 1, the TiO concentration was adjusted after adding _2.16 moles of an aqueous strontium chloride solution to the peptized metatitanic _acid slurry so that the SrO/TiO mole ratio was 1.15. Strontium titanate particles 2 were obtained in the same manner except that the concentration was changed to 1.083 mol/L.

<Production Example 3 of Strontium Titanate Particles>
For production example 1 of strontium titanate particles, 2.54 mol of an aqueous strontium chloride solution was added to the peptized metatitanic acid slurry so that the SrO/TiO ₂ molar ratio was 0.921. Strontium titanate particles 3 were obtained by performing the same operation except that 440 mL of L sodium hydroxide aqueous solution was added over "45 minutes" but over "80 minutes".

<Production Example 4 of Strontium Titanate Particles>
For production example 1 of strontium titanate particles, 2.54 mol of an aqueous strontium chloride solution was added to the peptized metatitanic acid slurry so that the SrO/TiO ₂ molar ratio was 0.933. Strontium titanate particles 4 were obtained by performing the same operation except that 440 mL of L sodium hydroxide aqueous solution was added over “45 minutes” but over “60 minutes”.

<Production Example 5 of Strontium Titanate Particles>
For strontium titanate particle production example 1, 300 g of the dried product is put into a dry particle compounding device (Nobilta NOB-130 manufactured by Hosokawa Micron), and the treatment temperature is 30 ° C. Time to process with a rotary treatment blade of 90 m / sec. was changed from "10 minutes" to "15 minutes", and the amount of trifluoropropyltrimethoxysilane added to the solid content was changed from 4.6% by mass to 4.0% by mass. Then, strontium titanate particles 5 were obtained.

<Production Example 6 of Strontium Titanate Particles>
2.54 mol of an aqueous solution of strontium chloride was added to the peptized metatitanic acid slurry to make the SrO/TiO ₂ molar ratio 1.35 for the strontium titanate particle production example 1; Strontium titanate particles 6 were obtained in the same manner, except that the amount of trifluoropropyltrimethoxysilane added was changed from 4.6% by mass to 7.5% by mass.

<Production Example 7 of Strontium Titanate Particles>
2.54 mol of an aqueous solution of strontium chloride was added to the peptized metatitanic acid slurry to make the SrO/TiO ₂ molar ratio 1.35 for the strontium titanate particle production example 1; Strontium titanate particles 7 were obtained in the same manner as described above, except that the added "trifluoropropyltrimethoxysilane" was changed to "3-isocyanatopropyltrimethoxysilane".

<Production Example 8 of Strontium Titanate Particles>
2.54 mol of an aqueous solution of strontium chloride was added to the peptized metatitanic acid slurry to make the SrO/TiO ₂ molar ratio 1.35 for the strontium titanate particle production example 1; Strontium titanate particles 8 were obtained in the same manner as described above, except that the added "trifluoropropyltrimethoxysilane" was changed to "trimethoxypentafluorophenylsilane".

<Production Example 9 of Strontium Titanate Particles>
For production example 1 of strontium titanate particles, 2.01 mol of an aqueous strontium chloride solution was added to the peptized metatitanic acid slurry so that the SrO/TiO ₂ molar ratio was 1.07. 4.6% by weight isobutyltrimethoxysilane and 4.6% by weight trifluoropropyltrimethoxysilane added to 1.0% by weight isobutyltrimethoxysilane and 3.0% by weight trifluoropropyltrimethoxysilane. Strontium titanate particles 9 were obtained in the same manner except that silane was used.

<Production Example 10 of Strontium Titanate Particles>
For production example 1 of strontium titanate particles, 2.01 mol of an aqueous strontium chloride solution was added to the peptized metatitanic acid slurry so that the SrO/TiO ₂ molar ratio was 1.07. 4.6% by weight isobutyltrimethoxysilane and 4.6% by weight trifluoropropyltrimethoxysilane when added to 2.0% by weight isobutyltrimethoxysilane and 2.0% by weight trifluoropropyltrimethoxysilane. Strontium titanate particles 10 were obtained in the same manner except that methoxysilane was used.

<Production Example 11 of Strontium Titanate Particles>
2.54 mol of an aqueous solution of strontium chloride was added to the peptized metatitanic acid slurry to make the SrO/TiO ₂ molar ratio 1.35 for the strontium titanate particle production example 1; 4.6 wt.% isobutyltrimethoxysilane and 4.6 wt.% trifluoropropyltrimethoxysilane when added to 7.2 wt.% isobutyltrimethoxysilane and 6.9 wt. Strontium titanate particles 11 were obtained in the same manner except that methoxysilane was used.

<Production Example 12 of Strontium Titanate Particles>
2.54 mol of an aqueous solution of strontium chloride was added to the peptized metatitanic acid slurry to make the SrO/TiO ₂ molar ratio 1.35 for the strontium titanate particle production example 1; 4.6% by weight isobutyltrimethoxysilane and 4.6% by weight trifluoropropyltrimethoxysilane when added to 7.5% by weight isobutyltrimethoxysilane and 6.9% by weight trifluoropropyltri Strontium titanate particles 12 were obtained in the same manner except that methoxysilane was used.

<Production Example 13 of Strontium Titanate Particles>
For production example 1 of strontium titanate particles, 2.54 mol of an aqueous strontium chloride solution was added to the peptized metatitanic acid slurry so that the SrO/TiO ₂ molar ratio was 0.918. Except that 440 mL of L sodium hydroxide aqueous solution was added over “45 minutes” but was added over “90 minutes”, and the amount of trifluoropropyltrimethoxysilane was changed from 4.6% by mass to 3.2% by mass. performed the same operation to obtain strontium titanate particles 13.

<Production Example 1 of Calcium Titanate Particles>
Calcium titanate particles were obtained in the same manner as in Production Example 1 of Strontium Titanate Particles, except that calcium chloride was used instead of adding the strontium chloride aqueous solution to the peptized metatitanic acid slurry.

<Production Example 1 of Magnesium Titanate Particles>
Magnesium titanate particles were obtained in the same manner as in Production Example 1 of Strontium Titanate Particles, except that magnesium chloride was used instead of adding the strontium chloride aqueous solution to the peptized metatitanate slurry.

<Production Example 1 of Potassium Titanate Particles>
Potassium titanate particles were obtained in the same manner as in Production Example 1 of Strontium Titanate Particles, except that potassium chloride was used instead of adding the strontium chloride aqueous solution to the peptized metatitanic acid slurry.

Next, a production example of titanium oxide other than the metal titanate fine particles used as the external additive 1 will be described below.

<Production Example 1 of Titanium Oxide Particles>
An ilmenite ore containing 50% by mass of TiO ₂ equivalent was used as a starting material. After drying this raw material at 150° C. for 2 hours, sulfuric acid was added and dissolved to obtain an aqueous solution of TiOSO ₄ . After concentrating this and adding 4.5 parts by mass of titania sol having rutile crystals as a seed, it was hydrolyzed at 110° C. to obtain a slurry of TiO(OH) ₂ containing impurities. This slurry was repeatedly washed with water at pH 5-6 to sufficiently remove sulfuric acid, FeSO ₄ and impurities. Then, a slurry of high-purity metatitanic acid [TiO(OH) ₂ ] was obtained.

This slurry was filtered, calcined at 180° C. for 2 hours, and then pulverized repeatedly by a jet mill until aggregates of fine particles disappeared. This titanium oxide is dispersed in ethanol, and 4.6% by mass of isobutyltrimethoxysilane and 4.6% by mass of trifluoropropyltrimethoxysilane are added to 100 parts by mass of the titanium oxide solid content to coalesce the particles. were mixed dropwise with sufficient stirring so as not to cause the reaction. Furthermore, the pH of the slurry was adjusted to 6.5 while sufficiently stirring.

This was filtered, dried, heat-treated at 170° C. for 2 hours, and then pulverized repeatedly by a jet mill until the aggregates of titanium oxide disappeared, to obtain titanium oxide particles 1 .

<Production Example 2 of Titanium Oxide Particles>
Titanium oxide particles 2 were obtained in the same manner as in Production Example 1 of titanium oxide particles, except that the temperature for hydrolysis was changed from 110°C to 125°C.

<Production Example 3 of Titanium Oxide Particles>
Where 4.6% by mass of isobutyltrimethoxysilane and 4.6% by mass of trifluoropropyltrimethoxysilane were added to Titanium Oxide Particle Production Example 1, only 9.2% by mass of isobutyltrimethoxysilane was added. Titanium oxide particles 3 were obtained by performing the same operation except that the

Synthesis examples of polymerizable monomers and polymers in charge control resins used in the production of toner particles are described below, and their physical properties are shown in Table 2.

<Synthesis Example of Polymerizable Monomer N-1>
18 g of 2,4-dihydroxybenzoic acid was dissolved in 150 mL of methanol, 36.9 g of potassium carbonate was added, and the mixture was heated to 65°C. A mixture of 18.7 g of 4-(chloromethyl)styrene and 100 mL of methanol was added dropwise to this reaction solution, and the mixture was reacted at 65° C. for 3 hours. After cooling the reaction solution, it was filtered and the filtrate was concentrated to obtain a crude product. The crude product was dispersed in 1.5 L of water of pH=2 and extracted by adding ethyl acetate. Then, it was washed with water, dried over magnesium sulfate, and ethyl acetate was distilled off under reduced pressure to obtain a precipitate. After washing the precipitate with hexane, it was purified by recrystallization with toluene and ethyl acetate to obtain 20.1 g of a polymerizable monomer N-1 represented by the following structural formula (6).

<Synthesis Example of Polymerizable Monomer N-2>
(Step 1)
100 g of 2,5-dihydroxybenzoic acid and 1441 g of 80% sulfuric acid were heated to 50° C. and mixed. 144 g of tert-butyl alcohol was added to this dispersion and stirred at 50° C. for 30 minutes. Thereafter, an operation of adding 144 g of tert-butyl alcohol to this dispersion and stirring for 30 minutes was repeated three times. The reaction solution was cooled to room temperature and slowly poured into 1 kg of ice water. The precipitate was filtered, washed with water, and then washed with hexane. This precipitate was dissolved in 200 mL of methanol and reprecipitated in 3.6 L of water. After filtration, drying at 80° C. gave 74.9 g of a salicylic acid intermediate represented by the following structural formula (7).

(Step 2)
For the synthesis example of polymer N-1, the same operation was performed except that 25 g of the intermediate of formula (7) was used instead of dissolving 18 g of 2,4-dihydroxybenzoic acid in 150 mL of methanol. 2.01 g of polymerizable monomer N-2 represented by formula (8) was obtained.

<Synthesis Example of Polymerizable Monomer N-3>
The same operation as in Synthesis Example of Polymerizable Monomer N-1 was performed except that 18 g of 2,4-dihydroxybenzoic acid was replaced with 18 g of 2,3-dihydroxybenzoic acid, and the following formula (9) was obtained. 2.01 g of the polymerizable monomer N-3 shown in .

<Synthesis Example of Polymerizable Monomer N-4>
The same operation as in Synthesis Example of polymerizable monomer N-1 was performed except that 18 g of 2,4-dihydroxybenzoic acid was replaced with 18 g of 2,6-dihydroxybenzoic acid, and the following formula (10) was obtained. 2.01 g of the polymerizable monomer N-4 shown in .

<Synthesis Example of Polymer 1>
9.2 g of the polymerizable monomer N-1 represented by structural formula (6) and 60.1 g of styrene were dissolved in 42.0 ml of DMF, stirred for 1 hour with nitrogen bubbling, and then heated to 110.degree. A mixture of 2.1 g of tert-butyl peroxyisopropyl monocarbonate (manufactured by NOF Corporation, trade name Perbutyl I) as an initiator and 42 ml of toluene was added dropwise to this reaction solution. Furthermore, it reacted at 110 degreeC for 4 hours. Then, it was cooled and added dropwise to 1 L of methanol to obtain a precipitate. After dissolving the resulting precipitate in 120 ml of THF, it was added dropwise to 1.80 L of methanol to precipitate a white precipitate, which was filtered and dried at 90° C. under reduced pressure to obtain 57.6 g of polymer 1. The NMR and acid value of the obtained polymer 1 were measured to confirm the content of the component derived from the polymer monomer N-1.

<Synthesis Examples of Polymers 2 to 4>
Polymers 2 to 4 were obtained in the same manner as in Polymer Production Example 1, except that the amounts of raw materials charged were changed as shown in Table 2.

<Synthesis Example of Polymer 5>
200 parts by mass of xylene was charged into a reactor equipped with a stirrer, a condenser, a thermometer and a nitrogen inlet tube, and refluxed under a nitrogen stream. As a monomer
6.0 parts by mass of 2-acrylamido-2-methylpropanesulfonic acid and 72.0 parts by mass of styrene and 18.0 parts by mass of 2-ethylhexyl acrylate were mixed, added dropwise to the reaction vessel with stirring, and held for 10 hours. Thereafter, distillation was performed to remove the solvent, and the residue was dried at 40° C. under reduced pressure to obtain Polymer 5.

<Synthesis Example of Polymer 6>
Polymer 6 was obtained in the same manner as Polymer 5, except that the materials were changed as follows.
2-acrylamide-2-methylpropanesulfonic acid 6.0 parts by mass Styrene 78.0 parts by mass 2-ethylhexyl acrylate 16.0 parts by mass Dimethyl-2,2'-azobis(2-methylpropionate) 5.0 parts by mass Department

<Production Example 1 of Toner Particles>
C.I. I. 19.5 parts by mass of Pigment Blue 15:3 was prepared. These were introduced into an attritor (manufactured by Mitsui Mining Co., Ltd.) and stirred at 200 rpm for 180 minutes at 25° C. using zirconia beads (140 parts by mass) with a radius of 1.25 mm to prepare a masterbatch dispersion liquid 1. .

On the other hand, 450 parts by mass of 0.1M-Na ₃ PO ₄ aqueous solution was added to 710 parts by mass of ion-exchanged water and heated to 60°C, and then 67.7 parts by mass of 1.0M-CaCl ₂ aqueous solution was gradually added. An aqueous medium containing a calcium phosphate compound was obtained.

・Masterbatch dispersion liquid 1 40 parts by mass ・Styrene monomer 49.5 parts by mass ・N-butyl acrylate monomer 16.5 parts by mass ・Hydrocarbon wax 9 parts by mass (Fischer-Tropsch wax, maximum endothermic peak peak temperature = 78°C, Mw = 750)
Charge control resin 1 0.5 parts by mass The above materials were heated to 65° C., and uniformly dissolved and dispersed at 5,000 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). Into this was dissolved 7.1 parts by mass of a 70% toluene solution of 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate as a polymerization initiator to prepare a polymerizable monomer composition.

The above polymerizable monomer composition was added to the aqueous medium, and stirred at 12,000 rpm for 10 minutes with a TK homomixer at a temperature of 65° C. under N ₂ atmosphere to form a polymerizable monomer composition. Granulated. After that, the temperature was raised to 67° C. while stirring with a paddle stirring blade, and when the polymerization conversion rate of the polymerizable vinyl monomer reached 90%, a 0.1 mol/liter sodium hydroxide aqueous solution was added. The pH of the aqueous dispersion medium was adjusted to 9. Further, the temperature was raised to 80° C. at a rate of temperature rise of 40° C./h, and the reaction was carried out for 4 hours. After completion of the polymerization reaction, residual monomers in the toner particles were distilled off under reduced pressure. After cooling the aqueous medium, hydrochloric acid was added to adjust the pH to 1.4, and the mixture was stirred for 6 hours to dissolve the calcium phosphate. After the toner particles were separated by filtration and washed with water, they were dried at a temperature of 40° C. for 48 hours. The obtained dried product is strictly classified and removed at the same time with a multi-division classifier (elbow jet classifier manufactured by Nittetsu Mining Co., Ltd.), and the weight average particle size (D4) is 6.3 μm and the average circular shape is obtained. Cyan colored toner particles 1 with a degree of 0.98 were obtained.

<Toner Particle Production Examples 2 to 7>
Toner Particles 2 to 7 were obtained in the same manner as in Toner Particle Production Example 1, except that the type and amount of charge control resin were changed as shown in Table 3.

Examples are shown below.

[Example 1]
With respect to 100.0 parts by mass of toner particles 1 obtained, 0.5 parts by mass of metal titanate fine particles 1 as external additive 1 and dimethyl silicone oil (20 mass % ) and triboelectrically charged to the same polarity (negative polarity) as the toner particles (number average primary particle diameter: 10 nm, BET specific surface area: 170 m ² /g) 1.5 parts by mass was added to the FM mixer. (FM10C; manufactured by Nippon Coke Co., Ltd.) was mixed for 12 minutes at 3300 r/min to obtain Toner 1. Thereafter, the mixture was sieved through a mesh having an opening of 200 μm to obtain negative triboelectric charging toner 1 as shown in Table 4.

The obtained toner was evaluated by the evaluation equipment described below, and the results are shown in Table 5.

<Evaluation machine>
An HP laser beam printer, HP LaserJet Enterprise M653x, was modified so that it could operate even when only one color process cartridge was installed, and the evaluation was performed. As the evaluation paper, CS-680 sold by Canon Marketing Japan was used. The toner was filled in a predetermined process cartridge (filling amount: 320 g).

<Durability (1): development streaks>
Evaluation of development streaks was performed in a normal temperature and normal humidity environment (temperature of 25° C., relative humidity of 50%). Assuming a long-term endurance test, a horizontal line pattern with a printing rate of 1% was set to 2 sheets/1 job, and the setting was made so that the next job was started after the machine was temporarily stopped between jobs. In this mode, a total of 30,000 images were tested, and the number of vertical streaks in an all-black image on the 30,000th sheet was visually confirmed as follows.
A: No streaks.
B: One streak.
C: Two streaks.
D: Three or more streaks.

<Durability (2): Streaks Caused by Contamination of Charging Roller>
The charging roller contamination streak was evaluated under a normal temperature and normal humidity environment (temperature of 25° C., relative humidity of 50%). Assuming a long-term endurance test, a horizontal line pattern with a printing rate of 1% was set to 2 sheets/1 job, and the setting was made so that the next job was started after the machine was temporarily stopped between jobs. In this mode, a total of 30,000 images were printed, and the number of streaks caused by toner that slipped through the cleaning on the electrophotographic roller was measured.
A: No streaks.
B: 1 to 2 streaks.
C: 3 to 4 streaks.
D: 5 or more streaks.

<Electrification Stability (1): Poor Regulation>
The poor regulation was evaluated in a low-temperature, low-humidity environment (temperature of 15° C., relative humidity of 10%), which is severe against charge-up. Assuming a long-term endurance test, a horizontal line pattern with a printing rate of 1% was set to 2 sheets/1 job, and the setting was made so that the next job was started after the machine was temporarily stopped between jobs. In the above mode, a total of 32,000 images were tested, and the images were visually confirmed every 500 sheets up to the 32,000th sheet. The toner regulating member and the toner carrier were poorly regulated, and the number of sheets until the image was uneven due to the toner that could not be regulated on the toner carrier was evaluated as follows.
A: No occurrence.
B: Occurs on the 31001st to 32000th sheets.
C: Occurs on the 30001st to 31000th sheets.
D: Occurs up to the 30000th sheet.

<Electrification stability (2): leaving fog>
The standing fogging was evaluated in a high-temperature and high-humidity environment (temperature of 30° C., relative humidity of 80%), which is disadvantageous for charging rise. First, an all-white image was printed on evaluation paper with a post-it note pasted around the bottom center, and the difference in density between the portion hidden by the post-it note and the portion not covered by the post-it note was used as the initial fog value. Assuming a long-term endurance test, a horizontal line pattern with a printing rate of 1% was set to 2 sheets/1 job, and the setting was made so that the next job was started after the machine was temporarily stopped between jobs. In this mode, a total of 20,000 images were printed, and the power to the machine was turned off and the developing device was left in the machine for 72 hours immediately after the printing of 20,000 images. After leaving, the machine was turned on again, an image similar to that of the initial fogging was printed, and the density difference was taken as the value of the leaving fog. A reflection densitometer (reflectometer model TC-6DS manufactured by Tokyo Denshoku Co., Ltd.) was used, and an amber light filter was used as a filter. Evaluation criteria were set as follows.
A: Less than 2.0 B: 2.0 or more and less than 3.0 C: 3.0 or more and less than 4.0 D: 4.0 or more

[Examples 2 to 20, Comparative Examples 1 to 4]
Toners 2 to 25 were obtained in the same manner as in Toner 1 Production Example, except that the type of toner particles and the type and amount of external additive were changed as shown in Table 4.

Evaluation was performed in the same manner as in Example 1. Table 5 shows the evaluation results.

Claims (10)

toner particles containing a binder resin, a colorant and a charge control resin;
Metal titanate fine particles present on the surface of the toner particles ;
A toner having
The charge control resin is a polymer of a polymerizable monomer represented by the following formula ( 6 ) , (8), (9) or (10) ,

the primary particles of the metal titanate fine particles have a number average particle size of 10 nm or more and 140 nm or less;
The surface of the metal titanate fine particles has a partial structure a represented by the following formula (2),
R ² —Si—O _3/2 formula (2)
(In the formula (2), R ² is a functional group having a substituent at its terminal with Hammett's substituent constant σm (meta) of 0.25 or more.)
The existence ratio of the partial structure a on the surface of the metal titanate fine particle measured by X-ray photoelectron spectroscopy (ESCA) is 0.110 or more and 0.220 or less .
A toner characterized by: 2. The toner according to claim 1 , wherein R2 in formula (2) ^is a CF3 - _terminated functional group. 3. The toner according to claim 1 , wherein the metal titanate fine particles further have a partial structure b represented by the following formula (3).
R ³ —Si—O _3/2 Formula (3)
(In Formula (3), R ³ is an alkyl group.) 4. The metal titanate fine particles according to any one of claims 1 to 3, wherein in a methanol wettability test , the methanol concentration is 30.0% or more and 60.0% or less when the transmittance of light having a wavelength of 780 nm is 50%. or the toner according to item 1. The toner according to any one of claims 1 to 4, wherein the primary particles of the metal titanate fine particles have a number average particle size of 10 nm or more and 80 nm or less. 6. The method according to any one of claims 1 to 5, wherein M/Ti ( molar ratio ) in the metal titanate fine particles is 0.70 or more and 0.90 or less, where titanium is denoted as Ti and metal other than titanium is denoted as M. The toner according to any one of claims 1 to 3. The toner according to any one of claims 1 to 6, wherein the metal titanate particles are strontium titanate. 8. The toner according to any one of claims 1 to 7 , wherein the toner contains 0.05 parts by mass or more and 2.00 parts by mass or less of the metal titanate fine particles with respect to 100.0 parts by mass of the toner particles. toner. 9. The toner particles according to any one of claims 1 to 8, wherein the charge control resin is contained in an amount of 0.05 parts by mass or more and 5.00 parts by mass or less with respect to 100.0 parts by mass of the binder resin. toner. 10. The charge control resin according to any one of claims 1 to 9, wherein the charge control resin is a polymer of a polymerizable monomer represented by the formula (6), (8), (9) or (10) and styrene. Toner described in .