JP6896508B2 - Toner manufacturing method - Google Patents

Description

The present invention relates to a belt toner manufacturing method is used in such an image forming method of an electrophotographic method.

Electrophotographic image forming devices are required to have higher speed, longer life, energy saving, and smaller size. In order to meet these demands, various performance improvements have been made to toner. It has been demanded. In particular, toner is required to be further improved in quality stability from the viewpoint of extending the service life.
In particular, in order to extend the service life, it is important that the quality does not change significantly regardless of the usage environment even in long-term durable use, and various external additives have been proposed.

For example, in long-term durable use, a hydrophobic surface treatment is often applied to the surface layer of the external additive in order to maintain good developability regardless of the usage environment. By making the surface hydrophobic, it is possible to prevent the amount of water adsorbed from changing depending on the usage environment and prevent the chargeability from changing depending on the usage environment. At the same time, by increasing the chargeability by surface treatment, it is possible to improve the chargeability of the toner and ensure the developability even in a high temperature and high humidity environment where it is difficult to charge. On the other hand, toner with improved charge rise tends to be in a charge-up state in which it is overcharged. At that time, as one of the means for controlling the chargeability, there was a method of stabilizing the chargeability of the toner by using an external additive as an electric resistance adjusting agent.

Strontium titanate particles, which are medium resistance materials, have been used as an electric resistance adjusting agent for satisfactorily adjusting the charge of toner. By subjecting strontium titanate to a hydrophobic and strongly charged surface treatment as described above, it is possible to prevent the toner from being charged up due to triboelectric charging while ensuring environmental stability and charge rise. .. As a result, excellent environmental stability and developability could be exhibited from the initial stage of durability.

However, conventional strontium titanate particles may migrate from toner particles due to repeated rubbing in the developing machine during long-term durable use, and the chargeability of the toner fluctuates at the end of long-term durable use, resulting in development. There was a tendency for the sex to decline. The transition means that the external additive moves from the toner particles to another toner or member. That is, the external additive does not stay on the original toner particles.

In Patent Document 1, strontium titanate particles having a controlled ratio of the number of moles of SrO to the number of moles of TiO ₂ (hereinafter, also referred to as SrO / TiO ₂ mole ratio) are externally added to the toner particles. It is disclosed to improve the environmental characteristics and charging characteristics of toner.
Patent Document 2 discloses that the fluidity and moisture resistance of the toner are improved by externally adding strontium titanate particles having a controlled particle size distribution to the toner particles.
Patent Document 3 discloses that by externally adding strontium titanate surface-treated with a silane coupling agent to the toner particles, the fluidity of the toner and the environmental stability of the charging characteristics are improved.

According to these techniques, a certain effect is confirmed on the environmental characteristics, charging characteristics, and suppression of image flow of the toner. However, there was room for further consideration regarding the case of long-term durability use.

JP-A-2015-137208 Japanese Unexamined Patent Publication No. 2003-277054 Patent No. 3047900

Hidetoshi Tsuchida, 3 others, "Chemical Structure and Static Charging of Polymers", Industrial Chemistry Magazine, 1966, Vol. 69, No. 10, p. 1978-1983 "A survey of hammett sintering 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 Katsumasa Miyamoto, 3 others, "Triboelectric Behavior of Various Polymer Films" Journal of the Society of Electrostatics, 2015, Vol. 39, No. 5, p. 216-220

An object of the present invention is to provide a method for producing a toner that solves the above problems. Specifically, it is an object of the present invention to provide a method for producing a toner having excellent environmental stability in terms of developability and fog even when used for a long period of time.

（上記式（３）中、Ｒ_１は、下記式（１）のＲ_１と同じ官能基であって、末端にハメットの置換基定数σｍ（メタ）が０．２５以上である置換基を持つ官能基であって、末端にＣＦ _３ を持つ官能基である。Ｒ_ａ〜Ｒ_ｃは、アルキル基である。）

（上記式（４）中、Ｒ _２ は、下記式（２）のＲ _２ と同じ官能基であって、アルキル基である。Ｒ _ｄ 〜Ｒ _ｆ は、アルキル基である。）
該チタン酸ストロンチウム粒子をトナー粒子に外添する工程（ｂ）
を有し、
該工程（ａ）は、上記式（３）で表される化合物および上記式（４）で表される化合物を撹拌混合した後、該チタン酸ストロンチウム母粒子に添加し、該チタン酸ストロンチウム母粒子の表面を処理することによって、該チタン酸ストロンチウム粒子を得る工程であり、
該チタン酸ストロンチウム粒子は、
（ｉ）一次粒子の個数平均粒径が１０ｎｍ以上８０ｎｍ以下であり、
（ｉｉ）メタノール濡れ性試験において、波長７８０ｎｍの光の透過率が５０％のときのメタノール濃度が４０．０％以上６０．０％以下であり、
（ｉｉｉ）チタン酸ストロンチウム母粒子と、該チタン酸ストロンチウム母粒子の表面に存在する表層と、を有する粒子であり、
該表層が、下記式（１）で表される部分構造ａおよび下記式（２）で表される部分構造ｂを有し、
Ｒ_１−Ｓｉ−Ｏ_３／２ 式（１）
（上記式（１）中、Ｒ_１は、上記式（３）のＲ_１と同じ官能基であって、末端にハメットの置換基定数σｍ（メタ）が０．２５以上である置換基を持つ官能基であって、末端にＣＦ _３ を持つ官能基である。）
Ｒ _２ −Ｓｉ−Ｏ _３／２ 式（２）
（上記式（２）中、Ｒ _２ は、上記式（４）のＲ _２ と同じ官能基であって、アルキル基である。）
Ｘ線光電子分光法（ＥＳＣＡ）を用いて測定される、該チタン酸ストロンチウム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以下であるトナーの製造方法が提供される。 Further, according to the present invention.
Toner particles and
Strontium titanate particles present on the surface of the toner particles and
It is a method of manufacturing a toner that manufactures a toner having
The manufacturing method is
The surface of the strontium titanate mother particles is treated with a compound represented by the following formula (3), which is a fluoroalkylsilane coupling agent, and a compound represented by the following formula (4), which is an alkylsilane coupling agent. obtaining a strontium titanate particles by (a), and,

(In the above formula (3), _{R 1} is the same functional group as _{R 1} of formula (1), Hammett substituent constant σm-terminated (meth) has a substituent at least 0.25 What functional groups der, Ru functional groups der with CF ₃ at the end _.R a to R _c is an alkyl group.)

(In the above formula (4), R ₂ is the same functional group as _{R 2 of the following} formula (2) and is an alkyl group. _{R d to} R _{f are alkyl groups.)}
Step of externally adding the strontium titanate particles to the toner particles (b)
Have,
In the step (a), the compound represented by the above formula (3) and the compound represented by the above formula (4) are stirred and mixed, and then added to the strontium titanate mother particles, and the strontium titanate mother particles are added. It is a step of obtaining the strontium titanate particles by treating the surface of the above.
The strontium titanate particles are
(I) Number of primary particles The average particle size is 10 nm or more and 80 nm or less.
(Ii) In the methanol wettability test, when the transmittance of light having a wavelength of 780 nm is 50%, the methanol concentration is 40.0% or more and 60.0% or less.
(Iii) A particle having a strontium titanate mother particle and a surface layer existing on the surface of the strontium titanate mother particle.
The surface layer has a partial structure a represented by the following formula (1) and a partial structure b represented by the following formula (2) .
R _{1 -Si-O 3/2} formula (1)
(In the above formula (1), _{R 1} is the same functional group as _{R 1} in the formula (3), the Hammett substituent constant σm-terminated (meth) has a substituent at least 0.25 What functional groups der, Ru functional groups der with CF ₃ at the end.)
R _{2 -Si-O 3/2} formula (2)
(In the above formula (2), _{R 2} is the same functional group as _{R 2} in the formula (4), an alkyl group.)
Provided is a method for producing a toner in which the abundance ratio of the partial structure a on the surface of the strontium titanate particles measured by X-ray photoelectron spectroscopy (ESCA) is 0.110 or more and 0.220 or less. ..

According to the present invention, it is possible to provide a toner having excellent environmental stability in terms of developability and fog even when used for a long period of time.

As described above, in order to maintain the developability and fog at a good level of the toner without depending on the environment, strontium titanate, which has been imparted with hydrophobicity and strong chargeability by surface treatment, is externally added. It is effective to do. It is considered that the reason is that the strontium titanate particles are a medium resistance material and are effective in controlling the chargeability of the toner by releasing the excessively charged charge to the toner particles. Further, it is considered that good environmental stability and charge rising property can be obtained by making the strontium titanate particles hydrophobic and strongly charged by surface treatment. As a result, it was possible to exhibit excellent environmental stability in terms of developability and fog.

However, conventional strontium titanate particles may migrate from toner particles due to rubbing in the developing machine during long-term durability use, and the toner chargeability at the end of durability fluctuates, and the developability and fog tend to deteriorate. was there.

Therefore, the present inventors have attempted to surface-treat the strontium titanate particles having a smaller particle size in order to suppress the migration of the strontium titanate particles from the toner particles. It was considered that by reducing the diameter, the electrostatic adhesion between the toner particles and the strontium titanate particles could be increased, and the migration of the strontium titanate particles could be suppressed.

In fact, by reducing the particle size of the strontium titanate particles, the migration of the strontium titanate particles can be suppressed even if they are repeatedly rubbed in the developing machine during long-term durability use. However, when the strontium titanate particles having a smaller particle size are surface-treated, the developability and fog deteriorate. When surface treatment is performed on strontium titanate particles having a small particle size, the charge-up suppressing function of the untreated strontium titanate particles is lost, and the excessively charged charge cannot be released, resulting in an increase in the amount of charge. Was the cause.

From the above viewpoints, we investigated a surface treatment method that can achieve both a charge rise property and a charge-up suppression function. As a result, it was found that the charge-up suppressing function can be maintained in the strontium titanate particles having a small particle size by partially surface-treating the surface layer in an island shape using a silane coupling agent. It was also found that by controlling the functional groups contained in the silane coupling agent and the wettability of methanol, it is possible to secure a good rising property of charging regardless of the environment.

Specifically, the present inventors
A toner having toner particles and strontium titanate particles existing on the surface of the toner particles.
The strontium titanate particles are
(I) Number of primary particles The average particle size is 10 nm or more and 80 nm or less.
(Ii) In the methanol wettability test, when the transmittance of light having a wavelength of 780 nm is 50%, the methanol concentration is 40.0% or more and 60.0% or less.
(Iii) Strontium titanate particles having a partial structure a represented by the formula (1) on the surface of the mother particles.
Use a toner characterized in that the abundance ratio of the partial structure a on the surface of the strontium titanate particles measured by X-ray photoelectron spectroscopy (ESCA) is 0.110 or more and 0.220 or less. so,
It has been found that the developability, fog, and charge rising property can be maintained at a good level regardless of the environment even during long-term durability use.
R _{1 -Si-O 3/2} formula (1)
(In the formula (1), R ₁ is a functional group having a substituent having a Hammett substituent constant σ _m (meta) of 0.25 or more at the terminal.)

The toner as described above can be produced by the following production method.
A method for producing a toner having toner particles and strontium titanate particles existing on the surface of the toner particles.
A step of treating the surface of the strontium titanate mother particles with a compound represented by the following formulas (3) and (4) to obtain strontium titanate particles, and a step of externally adding the strontium titanate particles to the toner particles. Has.

The external strontium titanate particles are
(I) Number of primary particles The average particle size is 10 nm or more and 80 nm or less.
(Ii) In the methanol wettability test, when the transmittance of light having a wavelength of 780 nm is 50%, the methanol concentration is 40.0% or more and 60.0% or less.
(Iii) The surface of the strontium titanate matrix particles has a partial structure a represented by the following formula (1).
The abundance ratio of the partial structure a on the surface of the strontium titanate particles measured by X-ray photoelectron spectroscopy (ESCA) is 0.110 or more and 0.220 or less.
R _{1 -Si-O 3/2} formula (1)
(In the formula (1), R ₁ is a functional group having a substituent having a Hammett substituent constant σ _m (meta) of 0.25 or more at the terminal.)

（式（３）中、Ｒ_１は式（１）中のＲ_１と同じ官能基であり、Ｒ_ａ〜Ｒ_ｃはアルキル基である。）
（式（４）中、Ｒ_２、Ｒ_ｄ〜Ｒ_ｆはアルキル基である。）

(In the formula (3), _{R 1} is the same functional group as _{R 1} in formula _(1), R a ~R _c is an alkyl group.)
(In formula (4), R ₂ , R _{d to} R _f are alkyl groups.)

Ordinary strontium titanate particles are particles that are more likely to be positively charged than inorganic fine particles generally used as an external additive, for example, untreated silica particles. As described above, it is necessary to apply a negatively charged and hydrophobic surface treatment to the strontium titanate particles in order to ensure the environmental stability and the rising property of the charge on the negative toner particles. However, when strontium titanate particles having a smaller diameter for the purpose of preventing migration from toner during long-term durability use are surface-treated, the developability and fog deteriorate. The present inventors have increased the specific surface area due to the smaller particle size of the particles, and the contribution of the surface is higher than that of the large particle size. I thought that the problem that did not exist became apparent for the first time. Therefore, the present inventors diligently studied the surface treatment state of the strontium titanate particles. As a result, for the strontium titanate particles having a small particle size, the chargeability of the surface layer structure formed after the treatment, the surface layer abundance ratio of the surface layer structure, and the wettability after the treatment were simultaneously controlled. By doing so, for the first time, it was found that the charge-up suppressing function and the rising property of charging can be compatible regardless of the environment.

When surface treatment is performed, the chargeability is negatively charged when the surface layer structure, especially the side chain has a greater effect than the main chain, and the end has a greater effect, and the functional group of the side chain is electron-attracting. , It is known that when it is electron-donating, it becomes positively charged (see Non-Patent Document 1). Therefore, when a structure is formed on the surface layer of strontium titanate by the silane coupling treatment, it is considered that the chargeability of the strontium titanate particles can be controlled by the functional group of the side chain. There is Hammett equation as an index of whether the substituent of the functional group is electron attracting property or electron donating property. Hammett's rule is an empirical rule that shows the effect of substituents on the reaction and equilibrium of benzene derivatives, and Hammett's substituent constant σ _m is a value that quantifies the degree of electron donating and electron attracting properties of substituents. It can be said (see Non-Patent Document 2). It is also known that there is a linear relationship between the Hammett substituent constant σ _{m and the logarithm of the amount of charge.} (See Non-Patent Document 3). Based on the above contents, it was considered that the rising property of charging is improved by forming a partial structure having a substituent having a large value of _{σ m, which is an electron attraction property, on the surface layer of the strontium titanate particles.}

The present inventors have made intensive studies, R ₁ of the partial structure a of the formula (1) is Hammett's substituent constant ends sigma _{m (meth)} has a substituent at least 0.25 It has been found that in the case of a functional group having, the rising property of charging is improved. Examples of the substituent having the Hammett substituent constant σ _m (meta) of 0.25 or more include CF ₃ , C ₆ F ₅ , NCO, CCl ₃ , NO ₂ , and COOH.
When _{the substituent constant σ m} (meta) of Hammett, which is a substituent at the end of _{R 1,} is 0.40 or more, the rising property of charging is further improved.
Furthermore, _{when the substituent of R 1} at the end is CF ₃ , the effect of increasing the negative charge property due to the intrusion of adsorbed water, which will be described later, can be greatly obtained, so that the charge rising property is further improved.

Next, for the purpose of suppressing the charge-up of the toner while maintaining the rising property of the charge, the retention of the control function of the charge property of the toner was examined. As a result, it was found that by setting the abundance ratio of the partial structure a on the surface of the strontium titanate particles to 0.110 or more and 0.220 or less, it is possible to suppress the charge-up of the toner while maintaining the rising property of charging. ..

The reason is not completely clear, but it is said that the partial structure a represented by the equation (1) has an electron-attracting functional group and thus suppresses the function of diffusing the charged-up charge. Conceivable. When the surface layer presence ratio of the partial structure a represented by the formula (1) is suppressed to 0.110 or more and 0.220 or less, the electric charge is diffused through the portion other than the partial structure a, and the electric charge is charged while improving the rising property of the electric charge. We believe that the sexual control function will be exerted. The abundance ratio of the partial structure a on the surface of the strontium titanate particles can be controlled by adjusting the surface treatment method, the combination of treatment agents, the molar ratio of the raw materials of the strontium titanate particles, and the production conditions.

_{Incidentally,} notation and R 1 _{-Si-O 3/2} represents the partial structure within the area surrounded by the rectangle indicated by broken lines _{below, -O 3/2} is
As shown in (a) below, three oxygens shared with Si atoms outside the region, or as shown in (b) below, two oxygens shared with Si atoms outside the region, titanium. It shows that it has one oxygen shared with the strontium titanum matrix particles.

（＊は、チタン酸ストロンチウム母粒子との結合部を表す。）

(* Indicates the bond with the strontium titanate mother particle.)

The strontium titanate particles used in the present invention have a methanol concentration of 40.0% or more and 60.0% or less when the transmittance of light having a wavelength of 780 nm is 50% in a wettability test with a mixed solvent of methanol / water. .. Hereinafter, the methanol concentration when the transmittance of light having a wavelength of 780 nm is 50% in the wettability test with a mixed solvent of methanol / water will be referred to as the degree of hydrophobicity. When the degree of hydrophobization is 40.0% or more, environmental fluctuations in the amount of water adsorbed can be suppressed, and changes in developability depending on the environment can be suppressed. When the degree of hydrophobization is lower than 40.0%, the rising property of charging is particularly lowered in a high temperature and high humidity environment. However, it was found that if the hydrophobicity becomes too high, the rising property of charging cannot be ensured even in a low temperature and low humidity environment. It was found that this is because the adsorbed water cannot penetrate into the surface layer, the effect of increasing the negative chargeability cannot be obtained, and the chargeability becomes low. The wettability required to obtain the effect of increasing the chargeability by invading the adsorbed water from the surface layer was when the degree of hydrophobicity was 60.0% or less (see Non-Patent Document 4). The degree of hydrophobization of the strontium titanate particles can be controlled by adjusting the surface treatment conditions of the strontium titanate particles.

The number average particle size of the primary particles of the strontium titanate particles used in the present invention is 10 nm or more and 80 nm or less, preferably 10 nm or more and 60 nm or less. When the number average particle size is within the above range, the migration of strontium titanate particles can be suppressed even during long-term durable use. The primary particles of the strontium titanate particles can be controlled by adjusting the molar ratio of the raw material of the strontium titanate particles and the production conditions.

The Sr / Ti molar ratio of the strontium titanate particles used in the present invention is preferably 0.70 or more and 0.90 or less. When the Sr / Ti molar ratio is 0.70 or more and 0.90 or less, the proportion of Ti having high reactivity with the surface treatment agent increases, and the abundance ratio of the partial structure a represented by the formula (1) is controlled. It will be easier to do. The Sr / Ti molar ratio can be controlled by adjusting the molar ratio of the raw material of the strontium titanate particles and the production conditions.

As typical strontium titanate particles, perovskite-type strontium titanate particles are produced by a normal pressure heating reaction method in which the particles are reacted at normal pressure instead of hydrothermal treatment using a pressurized container. A mineral acid deflated product of a hydrolyzate of a titanium compound is used as a titanium oxide source, and a water-soluble acidic compound is used as a strontium source, and the mixture is reacted while adding an alkaline aqueous solution at a temperature of 60 ° C. or higher, and then an acid. Manufactured by the method of processing. As a method of controlling the shape of the strontium titanate particles, a dry mechanical treatment method can also be adopted.

The atmospheric heating reaction method will be described. As the titanium oxide source, a mineral acid gelatinized product of a hydrolyzate of a titanium compound is used. Obtained in sulfuric acid method, it is preferably a 1.0 wt% or less SO ₃ content, and more preferably from 0.5 mass% or less. Strontium titanate-based fine particles having a good particle size distribution can be obtained by using metatitanic acid prepared by adjusting the pH to 0.8 or more and 1.5 or less with hydrochloric acid and defoliing it. If the SO ₃ content in metatitanic acid exceeds 1.0% by mass, gelatinization does not proceed.

As the strontium source, strontium nitrate, strontium chloride and the like can be used. As the alkaline aqueous solution, caustic alkali can be used, but among them, a sodium hydroxide aqueous solution is preferable.

Factors that affect the particle size of the obtained strontium titanate particles in the above production method include the mixing ratio of the titanium oxide source and the strontium source, the concentration of the titanium oxide source at the initial stage of the reaction, and the temperature at which the alkaline aqueous solution is added. And the addition rate and the like. Then, it can be appropriately adjusted to obtain strontium titanate particles having a target particle size and particle size distribution. In addition, in order to prevent the formation of strontium carbonate in the reaction process, it is preferable to prevent the mixing of carbon dioxide gas by reacting in a nitrogen gas atmosphere.

The mixing ratio of the titanium oxide source and the strontium source during the reaction is preferably 0.9 or more and 1.4 or less, and more preferably 1.05 or more and 1.20 or less in terms of the molar ratio of Sr / Ti. Since the strontium source has high solubility in water, the titanium oxide source has low solubility in water. Therefore, when the Sr / Ti molar ratio is 1 or less, the reaction product is not only strontium titanate but also unreacted titanium oxide. Is likely to remain. The concentration of the titanium oxide source at the initial stage of the reaction is preferably 0.05 mol / L or more and 1.3 mol / L or less, and more preferably 0.08 mol / L or more and 1.0 mol / L or less as _{TiO 2.}

By increasing the concentration of the titanium oxide source at the initial stage of the reaction, the primary particle size of the strontium titanate particles can be reduced.
The higher the temperature at which the alkaline aqueous solution is added, the better the crystallinity of the product can be obtained. However, since a pressure vessel such as an autoclave is required at 100 ° C. or higher, it is practically in the range of 60 ° C. to 100 ° C. Is preferable. As for the addition rate of the alkaline aqueous solution, the slower the addition rate, the larger the particle size of strontium titanate particles can be obtained, and the faster the addition rate, the smaller the particle size of strontium titanate particles can be obtained. The addition rate of the alkaline aqueous solution is preferably 0.001 equivalent / h or more and 1.2 equivalents / h or less, more preferably 0.002 equivalents / h or more and 1.1 equivalents / h or less, and is intended to be obtained. It can be appropriately adjusted according to the particle size.

Subsequently, the acid treatment will be described. When the mixing ratio of the titanium oxide source and the strontium source exceeds 1.0 in terms of the molar ratio of Sr / Ti, the unreacted strontium source remaining after the reaction is completed reacts with carbon dioxide in the air to produce strontium carbonate or the like. Since impurities are generated, the particle size distribution is lowered. Further, if impurities such as strontium carbonate remain on the surface, the organic surface treatment agent cannot be uniformly coated due to the influence of the impurities when performing the organic surface treatment for imparting hydrophobicity. Therefore, after adding the alkaline aqueous solution, acid treatment is performed to remove the unreacted strontium source.

In the acid treatment, the pH is preferably 2.5 or more and 7.0 or less, and more preferably 4.5 or more and 6.0 or less using hydrochloric acid. As the acid, nitric acid, acetic acid and the like can be used for the acid treatment in addition to hydrochloric acid. However, the use of sulfuric acid is not preferable because strontium sulfate, which has low water solubility, is generated.

Next, shape control will be described. As a method for obtaining the shape of the strontium titanate particles used in the present invention, dry mechanical treatment can be mentioned.
For example, a hybridizer (manufactured by Nara Machinery Co., Ltd.), Nobilta (manufactured by Hosokawa Micron Co., Ltd.), Mechanofusion (manufactured by Hosokawa Micron Co., Ltd.), Hiflex Gural (manufactured by EarthTechnica Co., Ltd.) and the like can be used. .. By treating the strontium titanate particles with these devices, the surface treatment property of strontium titanate can be improved. When controlling the shape of strontium titanate particles by mechanical treatment, fine powder of strontium titanate particles may be generated. In order to remove fine powder, it is preferable to carry out 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 the acid, nitric acid, acetic acid and the like can be used for the acid treatment in addition to hydrochloric acid. The mechanical treatment for controlling the shape of the strontium titanate particles is preferably carried out before the surface treatment of the strontium titanate particles is performed.

The surface treatment of the strontium titanate particles of the present invention will be described. In order to obtain the partial structure a of the surface of strontium titanate used in the present invention represented by the formula (1), a surface coating with a silane coupling agent can be used. As the silane coupling agent, a fluoroalkylsilane coupling agent, an isocyanate silane coupling agent, or the like can be used. It is more preferable to use a silane coupling agent having R _{1 having 10 or less carbon atoms.} Examples of the treatment method include a wet method in which a surface treatment agent or the like to be treated is dissolved and dispersed in a solvent, strontium titanate particles are added thereto, and the solvent is removed while stirring. Further, a dry method in which a coupling agent, a fatty acid metal salt and strontium titanate particles are directly mixed and treated while stirring can be mentioned.

As a method for obtaining the abundance ratio of the partial structure a represented by the formula (1), a method of performing treatment in combination with another silane coupling agent, surface coating with a hydrophobic agent such as silicone oil, and then treatment. There is a method to do. By mixing and stirring a plurality of types of silane coupling agents, the bonding between the coupling agents proceeds, and the surface layer of the strontium titanate particles can be easily treated in an island shape, which is more preferable as a treatment method.

As the 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 (2) on the surface of strontium titanate. By obtaining the partial structure b represented by the formula (2) on the surface of strontium titanate, the environmental stability is further improved. Particularly preferably, an alkylsilane coupling agent which is an alkyl group having 3 or more and 6 or less carbon atoms _{in R 2 is used.}
R _{2 -Si-O 3/2} formula (2)
(In formula (2), R ₂ is an alkyl group.)

The amount of the strontium titanate particles added in the present invention is preferably 0.05 parts by mass or more and 5.0 parts by mass or less when the toner particles are 100 parts by mass.
The average circularity of the toner particles is preferably 0.960 or more. When it is 0.960 or more, the fine line reproducibility is also improved. More preferably, it is 0.970 or more.

The method for producing the toner particles is not particularly limited. For example, a method for directly producing 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 can be mentioned. Further, a pulverization method may be used, or the toner obtained by the pulverization method may be made into a thermal sphere.
Among them, a toner produced by a suspension polymerization method is preferable because the individual particles are substantially spherical and the distribution of the amount of charge is relatively uniform, so that the toner has high transferability.

The suspension polymerization method is a method for producing toner particles through a granulation step and a polymerization step. In the granulation step, a polymerizable monomer composition having a polymerizable monomer that produces a binder resin, a colorant, and if necessary, an additive such as wax is dispersed in an aqueous medium and is polymerizable. Produce droplets of monomeric composition. In the polymerization step, the polymerizable monomer in the droplet is polymerized.

The toner of the present invention is preferably a toner having toner particles having a core portion and a shell portion. By adopting a core-shell structure having a shell portion on the surface of the core portion, it is possible to prevent charging defects caused by the core portion exuding to the surface of the toner particles.

The resin that forms the shell portion of the toner particles of the present invention is preferably formed of a resin such as a polyester resin, a styrene-acrylic copolymer, or a styrene-methacryl copolymer, but a polyester resin is most preferable.
The resin forming the shell portion is preferably used in an amount of 0.01 parts by mass or more and 20.0 parts by mass or less, and more preferably 0.5 parts by mass or more and 10.0 parts by mass or less per 100 parts by mass of the binder resin. ..

A vinyl-based polymerizable monomer can be mentioned as a preferable polymerizable monomer that can be used to produce a binder resin.
Specifically, for example, the following can be mentioned. Butyl; styrene derivatives such as α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene; methylacrylate, ethylacrylate, n-propylacrylate, Acrylic polymerizable monomers such as iso-propyl acrylate, n-butyl acrylate, iso-butyl acrylate, tert-butyl acrylate, 2-ethylhexyl acrylate; methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, iso-propyl methacrylate , N-butyl methacrylate, iso-butyl methacrylate, tert-butyl methacrylate and other methacrylic polymerizable monomers; methylene aliphatic monocarboxylic acid esters; vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate, benzoate Vinyl esters such as vinyl acid acid and vinyl formate.

The toner particles preferably contain wax.
Examples of the wax component include the following. Petroleum waxes and derivatives such as paraffin wax, microcrystallin wax, petrolatum; Montan wax and derivatives thereof; Hydrocarbon waxes and derivatives thereof by Fishertropus method; Polyolefin waxes such as polyethylene and polypropylene and derivatives thereof; Carnauba wax, Natural waxes such as candelilla wax and derivatives thereof. Derivatives include oxides, block copolymers with vinyl-based monomers, graft-modified products, fatty acids such as higher fatty alcohols, stearic acid, and palmitic acid, or compounds thereof, acid amide waxes, and ester waxes.

The toner particles contain a colorant.
As the black colorant, carbon black, a magnetic material, and a black colorant using the following yellow / magenta / cyan colorants are used.

Examples of the yellow colorant include compounds typified by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds. Specifically, the following can be mentioned. C. 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.

Examples of the magenta colorant 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 can be mentioned. C. 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 Bio Red 19.

Examples of the cyan colorant include a copper phthalocyanine compound and its derivative, an anthraquinone compound, and a basic dye lake compound. 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 alone or in the form of a solid solution. The colorant is selected in terms of hue angle, saturation, lightness, light resistance, OHP transparency, and dispersibility in toner. The amount of the colorant 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 or the binder resin that produces the binder resin.

Further, the toner of the present invention can be made into a magnetic toner by containing a magnetic substance as a colorant. Examples of the magnetic material include the following. Metals such as iron oxide, iron, cobalt, nickel such as magnetite, hematite, ferrite or these metals and aluminum, copper, magnesium, tin, zinc, berylium, calcium, manganese, selenium, titanium, tungsten, vanadium. Alloys with metals and mixtures thereof.

The surface-modified magnetic material is more preferable as the magnetic material. When the magnetic toner is prepared by a polymerization method, it is preferable that the magnetic toner is hydrophobized with a surface modifier which is a substance that does not inhibit polymerization. Examples of such a surface modifier include a silane coupling agent and a titanium coupling agent. These magnetic materials preferably have a number average particle diameter of 2.0 μm or less, and 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, and 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.

Further, as a production method for producing toner particles by the pulverization method, the following examples can be mentioned.
In the raw material mixing step, as a material constituting the toner particles, a binder resin, a colorant, and if necessary, other additives and the like are weighed in a predetermined amount, blended, and mixed. Examples of the mixing device include a double-con mixer, a V-type mixer, a drum-type mixer, a super mixer, an FM mixer, a Nauter mixer, and a mechano hybrid (manufactured by Nippon Coke Industries Co., Ltd.).

Next, the mixed materials are melt-kneaded to disperse the colorant and the like in the binder resin. In the melt-kneading step, a batch-type kneader such as a pressure kneader or a Bambary mixer or a continuous-type kneader can be used. Single-screw or twin-screw extruders have become the mainstream because of their superiority in continuous production. For example, KTK type twin-screw extruder (manufactured by Kobe Steel Co., Ltd.), TEM type twin-screw extruder (manufactured by Toshiba Machine Co., Ltd.), PCM kneader (manufactured by Ikekai), twin-screw extruder (KTC). Examples include Ktk Inc.), Co-Kneader (Bus Co., Ltd.), and Kneedex (Nippon Coke Industries Co., Ltd.). Further, 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.

Then, the cooled product of the resin composition is pulverized to a desired particle size in the pulverization step. In the crushing step, after coarse crushing with a crusher, it is further pulverized with a fine crusher. Examples of the crusher include a crusher, a hammer mill, and a feather mill. Examples of the pulverizer include a cryptron system (manufactured by Kawasaki Heavy Industries, Ltd.), a super rotor (manufactured by Nisshin Engineering Co., Ltd.), a turbo mill (manufactured by Freund Turbo Co., Ltd.), and an air jet method. A crusher can be mentioned.

Then, if necessary, the toner particles are classified using a classifier or a sieve as described below to obtain toner particles. Inertial classification type elbow jet (manufactured by Nittetsu Mining Co., Ltd.), centrifugal force classification type turboplex (manufactured by Hosokawa Micron Co., Ltd.), TSP separator (manufactured by Hosokawa Micron Co., Ltd.), faculty (manufactured by Hosokawa Micron Co., Ltd.).

Further, the toner particles may be made spherical. Examples of the system and the like that can be used for spheroidizing after pulverization include the following. Hybridization system (manufactured by Nara Machinery Co., Ltd.), mechanofusion system (manufactured by Hosokawa Micron Co., Ltd.), faculty (manufactured by Hosokawa Micron Co., Ltd.), Meteole Invo MR Type (manufactured by Nippon Pneumatic Industries Co., Ltd.).

Toner can be obtained by mixing strontium titanate particles and, if necessary, other external additives with the toner particles. As a mixer to be added to the toner particles, FM mixer (manufactured by Nippon Coke Industries Co., Ltd.), super mixer (manufactured by Kawata Co., Ltd.), Nobilta (manufactured by Hosokawa Micron Co., Ltd.), hybridizer (manufactured by Nara Machinery Co., Ltd.) (Made by Mfg. Co., Ltd.).

In addition, examples of the sieving device used for sieving coarse particles after external addition include the following. Ultrasonic (manufactured by Koei Sangyo Co., Ltd.); Resona Sheave, Gyroshifter (manufactured by Tokuju Kosakusho Co., Ltd.); Vibrasonic System (manufactured by Dalton Co., Ltd.); Soniclean (manufactured by Shinto Kogyo Co., Ltd.); Turbos Cleaner (manufactured by Freund Turbo Co., Ltd.); Microshifter (manufactured by Makino Sangyo Co., Ltd.).

The toner of the present invention may contain an external additive other than strontium titanate particles. In particular, in order to improve the fluidity and chargeability of the toner, a fluidity improver may be added. As the fluidity improver, for example, the following can be used.
Fluorine-based resin powders such as vinylidene fluoride fine powder and polytetrafuluoloethylene fine powder; fine powder silica such as wet manufacturing silica and dry manufacturing silica, fine powder titanium oxide, fine powder alumina, silane compounds, titanium cups Treated silica surface-treated with ringing agent, silicone oil; oxides such as zinc oxide and tin oxide; compound oxides such as strontium titanate, barium titanate, calcium titanate, strontium zirconate and calcium zirconate; carbon dioxide Calcium and carbonate compounds such as magnesium carbonate.

A preferable fluidity improver is a fine powder produced by vapor phase oxidation of a silicon halogen compound, which is so-called dry silica or fumed silica. For example, it utilizes the pyrolysis oxidation reaction of silicon tetrachloride gas in oxyhydrogen flame, and the basic reaction formula is as follows.
SiCl ₄ + 2H ₂ + O ₂ → SiO ₂ + 4HCl

In this manufacturing process, it is also possible to obtain a composite fine powder of silica and other metal oxides by using another metal halogen compound such as aluminum chloride or titanium chloride together with a silicon halogen compound, and these are also included as silica. To do.
The fluidity improver is preferable when the number average particle diameter of the primary particles is 5 nm or more and 30 nm or less because it can have high chargeability and fluidity.

Further, as the fluidity improver, treated silica fine powder obtained by hydrophobizing the silica fine powder generated by the vapor phase oxidation of the silicon halogen compound 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 due to nitrogen adsorption measured by the BET method.
It is preferable to use 0.01 parts by mass or more and 3 parts by mass or less of the fluidity improver in total with respect to 100 parts by mass of the toner particles.

The method for measuring various physical properties of the toner of the present invention will be described below.
When measuring the physical properties of the strontium titanate particles and the toner particles from the toner to which the strontium titanate particles are externally attached, the strontium titanate particles and other external additives can be separately measured from the toner. The toner is ultrasonically dispersed in methanol to remove strontium titanate particles and other external additives from the toner particles, and the toner is allowed to stand for 24 hours. Toner particles can be isolated by separating and recovering the precipitated toner particles from the strontium titanate particles dispersed in the supernatant and other external additives, and sufficiently drying them. In addition, strontium titanate particles can be isolated by treating the supernatant liquid by centrifugation.

<Number average particle size of primary particles of strontium titanate particles>
The number average particle size of the primary particles of strontium titanate particles is measured using a transmission electron microscope "JEM-2800" (JEOL Ltd.). The toner to which the strontium titanate particles are attached is observed, and the major axis of the primary particles of 100 strontium titanate particles is randomly measured in a field magnified up to 200,000 times to obtain the number average particle size. The observation magnification is appropriately adjusted according to the size of the strontium titanate particles.
Confirmation that the external additive is strontium titanate is carried out by STEM-EDS (scanning transmission electron microscope-energy dispersive spectroscopy) measurement.

The measurement conditions are as follows.
JEM2800 type transmission electron microscope: Acceleration voltage 200 kV
EDS detector: JED-2300T (JEOL Ltd., element area 100 mm ² ) is used. EDS analyzer: Noran System7 (Thermo Fisher Scientific) is used.
X-ray storage rate: 10000-15000 cps
Dead time: Adjust the electron dose so that it is 20 to 30%, and perform EDS analysis (total number of times 100 times or measurement time 5 minutes).

<Identification of partial structure on the surface of strontium titanate particles>
The partial structure on the surface of the strontium titanate particles is identified by a time-of-flight secondary ion mass spectrometer (TOF-SIMS). The following device is used under the following conditions to identify the partial structure from the fragment peak on the surface layer of strontium titanate.
-Measuring device: TRIFT-IV (trade name, manufactured by ULVAC-PHI, Ltd.)
・ Primary ion: Au ₃ ⁺
-Raster size: 100 μm x 100 μm
・ Neutralizing electron gun: used

<Abundance ratio of partial structure a on the surface of strontium titanate particles>
Elemental analysis of the surface of strontium titanate particles is performed using the following device under the following conditions.
-Measuring device: Quantum2000 (trade name, manufactured by ULVAC-PHI, Ltd.)
・ X-ray source: Monochrome Al Kα
-Xray Setting: 100 μmφ (25 W (15 KV))
・ Photoelectron extraction angle: 45 degrees ・ Neutralization condition: Combined use of neutralization gun and ion gun ・ Analysis area: 300 μm × 200 μm
-Pass Energy: 58.70 eV
・ Step size: 0.125eV
・ Analysis software: Maltipak (ULVAC-PHI, Inc.)

The surface concentration (atomic%) of each element was calculated from the measured peak intensity of each element.
Based on the surface concentration of each element, each element was assigned to each identified partial structure, and the abundance of each partial structure was specified. The abundance of the strontium titanate drug substance was taken 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 atomic concentration) Equation (5)

<Mole ratio of Sr / Ti of strontium titanate particles>
The measurement of the Sr and Ti contents of the strontium titanate particles used in the present invention can be determined by a fluorescent X-ray analyzer. For example, a wavelength dispersive fluorescent X-ray analyzer Axios advanced (manufactured by PANalytical) is used. Then, 1 g of the sample is weighed on a cup for powder measurement recommended by PANalytical and a special film is attached, and the elements from Na to U in the strontium titanate particles are measured by the FP method under the atmospheric pressure He atmosphere. .. At that time, assuming that all the detected elements are oxides, and assuming that the total mass of them is 100%, the contents of _{SrO and TiO 2 with respect to the total mass (mass%) by software SpectraEvolution (version 5.0L).} ) Is calculated as the oxide conversion value. After that, Sr / Ti (mass ratio) obtained by removing oxygen from the quantification result is obtained, and then converted to Sr / Ti (molar ratio) from the atomic weight of each element.

<Degree of hydrophobization of strontium titanate particles>
The degree of hydrophobization of the strontium titanate particles was measured by a powder wettability tester "WET-100P" (manufactured by Resuka Co., Ltd.).
A fluororesin-coated spindle-shaped rotor having a length of 25 mm and a maximum body 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 hydrous methanol solution consisting of 50% by volume of methanol and 50% by volume of water in the cylindrical glass container, 0.5 g of strontium titanate particles was added and 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 / sec 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 defined as the degree of hydrophobicity. .. The volume ratio of initial methanol to water is adjusted as appropriate according to the degree of hydrophobization of the sample.

<Average circularity of toner>
The average circularity of the toner is measured by the flow type particle image analyzer "FPIA-3000" (manufactured by Sysmex Co., Ltd.) under the measurement and analysis conditions at the time of calibration work.

The specific measurement method is as follows. First, about 20 mL of ion-exchanged water from which impure solids and the like have been removed in advance is placed in a glass container. Among them, as a dispersant, "Contaminone N" (a 10% by mass aqueous solution of a neutral detergent for cleaning a precision measuring instrument with a pH of 7 consisting of a nonionic surfactant, an anionic surfactant, and an organic builder, Wako Pure Chemical Industries, Ltd. ) Is diluted with ion-exchanged water about 3 times by mass, and about 0.2 mL of the diluted solution is added. Further, about 0.02 g of the measurement sample is added, and the dispersion treatment is performed for 2 minutes using an ultrasonic disperser to prepare a dispersion liquid for measurement. At that time, the dispersion liquid is appropriately cooled so that the temperature is 10 ° C. or higher and 40 ° C. or lower. As the ultrasonic disperser, a desktop ultrasonic cleaner disperser having an oscillation frequency of 50 kHz and an electrical output of 150 W (for example, "VS-150" (manufactured by Vervocreer Co., Ltd.)) is used. A predetermined amount of ion-exchanged water is placed in the water tank, and about 2 mL of the contaminanton N is added into the water tank.

For the measurement, the flow type particle image analyzer equipped with "UPlanApro" (magnification 10 times, numerical aperture 0.40) was used as the objective lens, and the particle sheath "PSE-900A" (Sysmex Corporation) was used as the sheath liquid. Made) was used. The dispersion liquid adjusted according to the above procedure is introduced into the flow type particle image analyzer, and 3000 toner particles are measured in the total count mode in the HPF measurement mode. Then, the binarization threshold value at the time of particle analysis is set to 85%, the diameter of the analyzed particle is limited to 1.985 μm or more and less than 39.69 μm, and the average circularity of the toner particles is obtained.

In the measurement, automatic focus adjustment is performed using standard latex particles before the start of measurement. Examples of standard latex particles include the following.
-Dilute "RESAARCH AND TEST PARTICLES Latex Microsphere Suspensions 5200A" manufactured by Duke Scientific with ion-exchanged water.
After that, it is preferable to perform focus adjustment every 2 hours from the start of measurement.

In the embodiment of the present application, a flow-type particle image analyzer that has been calibrated by Sysmex Corporation and has been issued a calibration certificate issued by Sysmex Corporation was used. The measurement was performed under the measurement and analysis conditions at the time of receiving the calibration certificate, except that the diameter of the analysis particle was limited to the equivalent circle diameter of 1.985 μm or more and less than 39.69 μm.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.
The strontium titanate particles were prepared as follows. The physical characteristics of the strontium titanate particles 1 to 11 are shown in Table 1.

<Production example 1 of strontium titanate particles>
Step S101:
After the metatitanic acid obtained by the sulfuric acid method was deironed and bleached, an aqueous sodium hydroxide solution was added to adjust the pH to 9.0, desulfurization was performed, and then neutralized to pH 5.8 with hydrochloric acid and washed with filtered water. Water was added to the washed cake to make _{a slurry of 1.85 mol / L as TiO 2} , and then hydrochloric acid was added to adjust the pH to 1.0 to perform a gelatinization treatment.

Step S102:
1.88 mol of desulfurized and deglued metatitanium acid _{was collected as TiO 2} and placed in a 3 L reaction vessel.
Step S103:
2.16 mol of an aqueous solution of strontium chloride was added to the deflated metatitanium acid slurry so that the SrO / TiO ₂ mol ratio was 1.15.
Step S104:
The TiO ₂ concentration was adjusted to 1.039 mol / L.
Step S105:
Next, after heating to 90 ° C. with stirring and mixing, 440 mL of a 10 mol / L sodium hydroxide aqueous solution was added over 45 minutes.
Step S106:
The reaction was completed by continuing stirring at a temperature of 95 ° C. for 1 hour.

Step S107:
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.
Step S108:
The obtained precipitate was decanted and washed, filtered and separated, and then dried in the air at 120 ° C. for 8 hours.
Step S109:
Subsequently, 300 g of the dried product was put into a dry particle composite device (Nobilta NOB-130 manufactured by Hosokawa Micron Co., Ltd.). The treatment was carried out at a treatment temperature of 30 ° C. and a rotary treatment blade of 90 m / sec for 10 minutes.

Step S110:
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 decanted and washed.
Step S111:
The slurry containing the precipitate was adjusted to 40 ° C., and hydrochloric acid was added to adjust the pH to 2.5.
Step S112:
Next, 4.6% by mass of isobutyltrimethoxysilane and 4.6% by mass of trifluoropropyltrimethoxysilane with respect to the solid content were added after stirring and mixing for 1 hour, and stirring and holding were continued for 10 hours.
Step S113:
A 5 mol / L sodium hydroxide solution was added to adjust the pH to 6.5, and stirring was continued for 1 hour.
Step S114:
The cake obtained by filtration and washing was dried in the air at 120 ° C. for 8 hours to obtain strontium titanate particles 1.

<Production example 2 of strontium titanate particles>
Strontium titanate particles 2 were obtained in the same manner as in Production Example 1 except that the TiO _{2 concentration was adjusted to 1.083 mol / L in step S104.}

<Production example 3 of strontium titanate particles>
Strontium titanate particles 3 were obtained in the same manner as in Production Example 1 except that the TiO _{2 concentration was adjusted to 0.988 mol / L in step S104.}

<Production example 4 of strontium titanate particles>
Strontium titanate particles 4 were obtained in the same manner as in Production Example 1 except that the TiO _{2 concentration was adjusted to 0.943 mol / L in step S104.}

<Production example 5 of strontium titanate particles>
In step S103, 2.54 mol of an aqueous solution of strontium chloride was added so that the SrO / TiO ₂ mol ratio was 1.35.
In step S112
Using "4.0% by mass" of "n-propyltrimethoxysilane" instead of "4.6% by mass" of isobutyltrimethoxysilane,
Strontium titanate particles 5 were obtained in the same manner as in Production Example 1 except for the above.

<Production example of strontium titanate particles 6>
In step S103, 2.54 mol of an aqueous solution of strontium chloride was added so that the SrO / TiO ₂ mol ratio was 1.35.
In step S112
Using "6.9% by mass" of isobutyltrimethoxysilane instead of "4.6% by mass" of isobutyltrimethoxysilane,
Strontium titanate particles 6 were obtained in the same manner as in Production Example 1 except for the above.

<Production example of strontium titanate particles 7>
In step S103, 2.54 mol of an aqueous solution of strontium chloride was added so that the SrO / TiO ₂ mol ratio was 1.35.
In step S112
Using 4.6% by mass of "3-isocyanatepropyltrimethoxysilane" instead of 4.6% by mass of "trifluoropropyltrimethoxysilane",
Strontium titanate particles 7 were obtained in the same manner as in Production Example 1 except for the above.

<Production example of strontium titanate particles 8>
In step S103, 2.54 mol of an aqueous solution of strontium chloride was added so that the SrO / TiO ₂ mol ratio was 1.35.
In step S112
Using 4.6% by mass of "trimethoxypentafluorophenylsilane" instead of 4.6% by mass of "trifluoropropyltrimethoxysilane",
Strontium titanate particles 8 were obtained in the same manner as in Production Example 1 except for the above.

<Production example of strontium titanate particles 9>
In step S103, 2.54 mol of an aqueous solution of strontium chloride was added so that the SrO / TiO ₂ mol ratio was 1.35.
In step S111
Instead of "adjusting the slurry containing the precipitate to 40 ° C.", "add hydrochloric acid to the slurry containing the precipitate to adjust the pH to 2.5, and then add 1.5% by mass of silicone oil to the solid content, and 1 Continue to stir and hold for hours, then adjust the temperature to 40 ° C. "
In step S112
Instead of "4.6% by mass of isobutyltrimethoxysilane and 4.6% by mass of trifluoropropyltrimethoxysilane are added after stirring and mixing for 1 hour and held for 10 hours with stirring", "3.0% by mass of tri. Fluoropropyltrimethoxysilane was added and the mixture was stirred and held for 10 hours. "
Strontium titanate particles 9 were obtained in the same manner as in Production Example 1 except for the above.

<Production example of strontium titanate particles 10>
In step S103, 2.54 mol of an aqueous solution of strontium chloride was added so that the SrO / TiO ₂ mol ratio was 1.35.
In step S112
Using "6.9% by mass" of trifluoropropyltrimethoxysilane instead of "4.6% by mass" of trifluoropropyltrimethoxysilane,
Strontium titanate particles 10 were obtained in the same manner as in Production Example 1 except for the above.

<Production example of strontium titanate particles 11>
The processing time in step S109 has been changed from "10 minutes" to "15 minutes".
In step S112
Instead of "adding 4.6% by mass of isobutyltrimethoxysilane and 4.6% by mass of trifluoropropyltrimethoxysilane after stirring and mixing for 1 hour with respect to the solid content, and holding the mixture for 10 hours with stirring", "solid content 4.4% by mass of isobutyltriethoxysilane and 4.0% by mass of trifluoropropyltrimethoxysilane were added after stirring and mixing for 3 hours, and the mixture was kept stirred for 8 hours.
Strontium titanate particles 11 were obtained in the same manner as in Production Example 1 except for the above.

<Production example of strontium titanate particles 12>
In step S103, 2.54 mol of the strontium chloride aqueous solution was added so that the SrO / TiO ₂ mol ratio was 0.935.
In step S105, instead of adding 440 mL of 10 mol / L aqueous sodium hydroxide solution over "45 minutes"
Addition over "1 hour",
In step S112
Using "4.0% by weight" of trifluoropropyltrimethoxysilane instead of "4.6% by weight" of trifluoropropyltrimethoxysilane,
Strontium titanate particles 12 were obtained in the same manner as in Production Example 1 except for the above.

<Production example of strontium titanate particles 13>
In step S103, 2.54 mol of an aqueous solution of strontium chloride was added so that the SrO / TiO ₂ mol ratio was 1.35.
In step S112
Instead of "adding 4.6% by mass of isobutyltrimethoxysilane and 4.6% by mass of trifluoropropyltrimethoxysilane after stirring and mixing for 1 hour with respect to the solid content, and holding the mixture for 10 hours with stirring", "solid content 4.6% by mass of isobutyltrimethoxysilane and 4.0% by mass of trifluoropropyltrimethoxysilane were added after stirring and mixing for 4 hours, and the stirring and holding was continued for 8 hours. "
Strontium titanate particles 13 were obtained in the same manner as in Production Example 1 except for the above.

<Production example of strontium titanate particles 14>
In step S107, after adding hydrochloric acid until the pH reaches 5.0,
Continuing to stir for "1 hour" instead of continuing to stir for "20 minutes",
Omitting steps S108 to 109,
In step S110, only "decantation cleaning" was performed,
In step S112, 4.6% by mass of isobutyltrimethoxysilane and 4.6% by mass of trifluoropropyltrimethoxysilane with respect to the solid content are stirred and mixed for 1 hour instead of "adding after stirring and mixing for 1 hour". "Addition" without
Strontium titanate particles 14 were obtained in the same manner as in Production Example 1 except for the above.

<Production example 15 of strontium titanate particles>
In step S103, 2.01 mol of an aqueous solution of strontium chloride was added so that the SrO / TiO ₂ mol ratio was 1.07.
In step S112
Instead of "4.6% by mass of isobutyltrimethoxysilane and 4.6% by mass of trifluoropropyltrimethoxysilane", "2.3% by mass of isobutyltrimethoxysilane and 2.3% by mass of trifluoropropyltri" Using "methoxysilane",
Strontium titanate particles 15 were obtained in the same manner as in Production Example 1 except for the above.

<Production example of strontium titanate particles 16>
In step S107, after adding hydrochloric acid until the pH reaches 5.0,
Continuing to stir for "1 hour" instead of continuing to stir for "20 minutes",
Omitting steps S108 to 109,
In step S110, only "decantation cleaning" was performed,
In step S112
Instead of "adding 4.6% by mass of isobutyltrimethoxysilane and 4.6% by mass of trifluoropropyltrimethoxysilane after stirring and mixing for 1 hour with respect to the solid content, and holding the mixture for 10 hours with stirring", "solid content 6.9% by mass of isobutyltrimethoxysilane and 4.0% by mass of trifluoropropyltrimethoxysilane were added to the mixture, and the mixture was kept stirred for 10 hours.
Strontium titanate particles 16 were obtained in the same manner as in Production Example 1 except for the above.

<Production example 17 of strontium titanate particles>
In step S104, the TiO ₂ concentration was adjusted to 0.943 mol / L.
In step S112
Instead of "adding 4.6% by mass of isobutyltrimethoxysilane and 4.6% by mass of trifluoropropyltrimethoxysilane after stirring and mixing for 1 hour with respect to the solid content, and holding the mixture for 10 hours with stirring", "solid content 6.0% by mass of isobutyltrimethoxysilane was added to the mixture, and the mixture was stirred and held for 5 hours.
Strontium titanate particles 17 were obtained in the same manner as in Production Example 1 except for the above.

<Manufacturing example of toner particles>
710 parts by mass of ion-exchanged water and _{850 parts of 0.1 mol / liter Na 3} PO ₄ aqueous solution were added to the four-mouthed container, and the high-speed agitator T.I. K. The temperature was maintained at 60 ° C. while stirring at 2000 times / sec using a homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). 68 parts by mass of a 1.0 mol / liter-CaCl ₂ aqueous solution was gradually added thereto to prepare an aqueous dispersion medium containing a dispersion stabilizer.

-Styrene 124 parts by mass-n-Butyl acrylate 36 parts by mass-Copper phthalocyanine pigment (CI pigment blue 15: 3) 13 parts by mass-Polyester resin (terephthalic acid-propylene oxide modified bisphenol A (2 mol adduct)) Copolymer, acid value: 10 mgKOH / g, glass transition temperature (Tg): 70 ° C., weight average molecular weight (Mw): 10,500) 10 parts by mass, load electric control agent (3,5-di-tert-) (Aluminum compound of butylsalicylic acid) 0.8 parts by mass, Fishertropsh wax (heat absorption main peak temperature: 78 ° C) 15 parts by mass

The above material was stirred with an Attritor (manufactured by Nippon Coke Industries, Ltd.) for 3 hours, and each component was dispersed in a polymerizable monomer to prepare a monomer mixture. A polymerization initiator of 1,1,3,3-tetramethylbutylperoxy2-ethylhexanoate (20.0 parts by mass (toluene solution 50%)) was added to the monomer mixture to form a polymerizable monomer composition. The thing was prepared. The polymerizable monomer composition was put into an aqueous dispersion medium, and granulated for 5 minutes while maintaining the rotation speed of the stirrer at 167 times / sec. Then, the high-speed stirrer was changed to a propeller-type stirrer, the internal temperature was raised to 70 ° C., and the reaction was carried out for 6 hours with slow stirring.

Next, the inside of the container was heated to a temperature of 80 ° C. and maintained for 4 hours, and then cooled to obtain slurry 1. Dilute hydrochloric acid was added to the container containing the slurry 1 to remove the dispersion stabilizer. Further, it was filtered, washed, and dried to obtain polymer particles (toner particles 1) having a weight average particle diameter (D4) of 6.2 μm. The circularity of the toner particles 1 was 0.980.

<Example 1>
With respect to the obtained toner particles 1 (100 parts by mass), strontium titanate particles 1 (1.5 parts by mass) and fumed silica (specific surface area measured by the BET method: 200 m ^{2 /} g) (1.5). (Mass part) was externally mixed under the following conditions.
・ FM mixer (FM10C; manufactured by Nippon Coke Industries Co., Ltd.)
-Toner particle charge: 1.8 kg, rotation speed: 60 times / sec, external attachment time: 5 minutes.
Then, it was sieved with a mesh having an opening of 200 μm to obtain a negative triboelectric toner 1 as shown in Table 2.
The following evaluation was performed using the obtained toner 1. The evaluation results are shown in Table 3.

<Evaluation machine>
The HP Color LaserJet Enterprise M651n laser beam printer manufactured by Hewlett-Packard Co., Ltd. was modified and evaluated so that it could operate even when only one color process cartridge was attached. As the evaluation paper, CS-680 (68.0 g / m ² ) sold by Canon Marketing Japan Inc. was used. Toner was filled into a given process cartridge.

<Developability depending on the environment>
The developability is evaluated in a low temperature and low humidity environment (temperature 10 ° C., relative humidity 14%), a normal temperature and humidity environment (temperature 25 ° C., relative humidity 50%), and a high temperature and high humidity environment (temperature 30 ° C., relative humidity 80%). Was done. Assuming a long-term durability test, the horizontal line pattern with a printing rate of 1% was set as 2 sheets / job, and the machine was set to stop once between jobs and then start the next job. In this mode, a total of 25,000 image density tests were performed, and the image density of the first image and the image density of the 25,000 image were measured.

As for the image density, a solid image of a 5 mm circle was output, and the reflection density was measured using a Macbeth densitometer (RD-914; manufactured by Macbeth; equipped with an SPI filter) which is a reflection densitometer. The larger the value, the better the developability.

<Cover>
The fog was evaluated in a low temperature and low humidity environment (temperature 10 ° C., relative humidity 14%) which is easily affected by charge-up. Immediately after the first image output and the 25,000th image output were performed for the evaluation of developability, solid white was passed through the paper, and the worst value of the reflection density on the white background was Ds, before image formation. The reflection average density of the transfer material was defined as Dr, and Dr-Ds was defined as the fog value. A reflection densitometer (Reflectometer model TC-6DS (with) Tokyo Denshoku Co., Ltd.) was used for measuring the reflection density on a white background, and an amber light filter was used as the filter. The smaller the value, the better the fog level.

<Image density stability>
The stability of the image density was evaluated in a high-temperature and high-humidity environment (temperature 30 ° C., relative humidity 80%), which is severe for the charge rise of the toner. After the first image output and the 25,000th image output were performed in the evaluation of the developability, a solid image was printed and the uniformity of the image was visually evaluated.
A: The image density is even and uniform.
B: The image density is slightly uneven.
C: The image density is uneven.

<Manufacturing examples of toners 2 to 11 and comparative toners 1 to 6>
Toners 2 to 11 and comparative toners 1 to 6 were obtained in the same manner as in the production example of toner 1 except that the types of strontium titanate particles were changed from the production example of toner 1 as shown in Table 2.

<Examples 2 to 11 and Comparative Examples 1 to 6>
The evaluation was performed in the same manner as in Example 1. The evaluation results are shown in Table 3.
Examples 7 to 9 are described as reference examples.

Claims (3)

Toner particles and
Strontium titanate particles present on the surface of the toner particles and
It is a method of manufacturing a toner that manufactures a toner having
The manufacturing method is
The surface of the strontium titanate mother particles is treated with a compound represented by the following formula (3), which is a fluoroalkylsilane coupling agent, and a compound represented by the following formula (4), which is an alkylsilane coupling agent. obtaining a strontium titanate particles by (a), and,

(In the above formula (3), _{R 1} is the same functional group as _{R 1} of formula (1), Hammett substituent constant σm-terminated (meth) has a substituent at least 0.25 What functional groups der, Ru functional groups der with CF ₃ at the end _.R a to R _c is an alkyl group.)

(In the above formula (4), R ₂ is the same functional group as _{R 2 of the following} formula (2) and is an alkyl group. _{R d to} R _{f are alkyl groups.)}
Step of externally adding the strontium titanate particles to the toner particles (b)
Have,
In the step (a), the compound represented by the above formula (3) and the compound represented by the above formula (4) are stirred and mixed, and then added to the strontium titanate mother particles, and the strontium titanate mother particles are added. It is a step of obtaining the strontium titanate particles by treating the surface of the above.
The strontium titanate particles are
(I) Number of primary particles The average particle size is 10 nm or more and 80 nm or less.
(Ii) In the methanol wettability test, when the transmittance of light having a wavelength of 780 nm is 50%, the methanol concentration is 40.0% or more and 60.0% or less.
(Iii) A particle having a strontium titanate mother particle and a surface layer existing on the surface of the strontium titanate mother particle.
The surface layer has a partial structure a represented by the following formula (1) and a partial structure b represented by the following formula (2) .
R _{1 -Si-O 3/2} formula (1)
(In the above formula (1), _{R 1} is the same functional group as _{R 1} in the formula (3), the Hammett substituent constant σm-terminated (meth) has a substituent at least 0.25 What functional groups der, Ru functional groups der with CF ₃ at the end.)
R _{2 -Si-O 3/2} formula (2)
(In the above formula (2), _{R 2} is the same functional group as _{R 2} in the formula (4), an alkyl group.)
Production of a toner characterized in that the abundance ratio of the partial structure a on the surface of the strontium titanate particles measured by X-ray photoelectron spectroscopy (ESCA) is 0.110 or more and 0.220 or less. Method. The method for producing a toner according to claim 1 , wherein the strontium titanate particles have an average number of primary particles of 10 nm or more and 60 nm or less. The method for producing a toner according to claim 1 or 2 , wherein R ₁ is a functional group having a substituent having a Hammett substituent constant σm (meta) of 0.40 or more at the terminal.