Toner

Abstract

To provide a toner that achieves stable image density for a long period of time in a high-speed machine even in a low-temperature and low-humidity environment.SOLUTION: The toner contains toner particles and inorganic fine particles, wherein the inorganic fine particles contain strontium titanate fine particles, Si-containing protruded portions are present on the surface of the strontium titanate fine particles, and the toner contains an amorphous polyester resin and elemental aluminum on the surface of the toner particles.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to toners used in image forming processes such as electrophotography. [Background technology]

[0002] In recent years, copiers and printers have become faster, longer-lasting, and more environmentally stable. This has created a demand for toner that can withstand the stress of long-term high-speed printing inside the cartridge, as well as stable image quality regardless of the usage environment. For example, Patent Document 1 discloses a method of incorporating an amorphous polyester resin into toner particles in order to improve stress resistance. From the viewpoint of charging characteristics, Patent Document 2 discloses a method of crosslinking an amorphous polyester resin with an aluminum element. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-147831 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-107769 Summary of the Invention [Problem to be solved by the invention]

[0004] However, even with these measures, there is still room for improvement in environments where charging is difficult to stabilize, such as low-temperature, low-humidity environments, in which high-speed, long-life copiers and printers are becoming more common. Even in toners in which durability and charging properties have been improved by using amorphous polyester resins or aluminum elements, inorganic fine particles on the surface of toner particles tend to migrate from the toner particles to components inside the developing device in high-speed machines.

[0005] This tendency is particularly pronounced in low-temperature, low-humidity environments. In these environments, toner tends to become overcharged, making it difficult to obtain stable image density. Specifically, when a large number of images of the same pattern are printed in a low-temperature, low-humidity environment, the toner in the printed and non-printed areas on the developing sleeve tends to become unevenly charged. If different images are printed consecutively while the toner remains in an unevenly charged state, the history of the previous image may appear as differences in image density, which can be a problem.

[0006] The present disclosure provides a toner that achieves stable image density over the long term in high-speed machines even in low-temperature, low-humidity environments. [Means for solving the problem]

[0007] The present disclosure provides a toner containing toner particles and inorganic fine particles, the inorganic fine particles contain strontium titanate fine particles, The strontium titanate microparticles have Si-containing protrusions on the surface thereof, The toner contains an amorphous polyester resin and an aluminum element on the surface of the toner particles. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to provide a toner that can achieve stable image density over a long period of time in a high-speed machine even in a low-temperature, low-humidity environment. [Brief explanation of the drawings]

[0009] [Figure 1] 1A and 1B are schematic diagrams of a powder resistivity measurement device. [Figure 2] FIG. 2 is a schematic diagram of a device for measuring the amount of triboelectric charge. DETAILED DESCRIPTION OF THE INVENTION

[0010] In the present disclosure, expressions such as "XX or more and YY or less" or "XX to YY" representing a numerical range mean a numerical range including the lower and upper limits, which are the endpoints, unless otherwise specified. Furthermore, when a numerical range is described in stages, the upper and lower limits of each numerical range can be arbitrarily combined. Furthermore, in the present disclosure, expressions such as "at least one selected from the group consisting of XX, YY, and ZZ" mean any of XX, YY, ZZ, a combination of XX and YY, a combination of XX and ZZ, a combination of YY and ZZ, or a combination of XX, YY, and ZZ. Note that when XX is a group, multiple XXs may be selected, and the same applies to YY and ZZ.

[0011] The present inventors believe that the reason why the toner according to the present disclosure can achieve stable image density over a long period of time in a high-speed machine even in a low-temperature, low-humidity environment is as follows. Cross-linking the amorphous polyester resin with aluminum improves the durability of the toner, but at the same time, excessive charging occurs in low-temperature, low-humidity environments, causing discontinuities in image density. One factor behind this is that in low-temperature, low-humidity environments, inorganic fine particles on the surface of toner particles tend to migrate, and the inorganic fine particles that do not migrate and remain on the surface of the toner particles tend to be charged unevenly.

[0012] One way to eliminate the difference in density of images is to use strontium titanate, which has low powder resistance. However, because strontium titanate particles are positive inorganic particles, they repel aluminum elements, which are also positive, and tend to migrate from the toner particles to other components, so the difference in density still becomes an issue. As a result of extensive research, the present inventors have found that using strontium titanate microparticles having Si-containing protrusions on their surfaces for toner particles containing an amorphous polyester resin and aluminum element is effective in improving the migration of the inorganic microparticles and excessive charging described above.

[0013] Since aluminum is an atom that is easily polarized to the positive direction, it is prone to electrostatic repulsion against inorganic fine particles that are also easily polarized to the positive direction, which makes the inorganic fine particles more likely to migrate to other components in the developing device.When some of the inorganic fine particles have migrated to other components, the toner surface is prone to become unbalanced in charge.

[0014] In contrast, the convex portions of strontium titanate microparticles having Si-containing convex portions on their surfaces are easily negatively polarized, making them less likely to repel aluminum elements and less likely to migrate from the toner surface even in low-temperature, low-humidity environments. Furthermore, the strontium titanate portion does not have an excessively high resistance, allowing for quick electron transfer with aluminum elements and amorphous polyester resin, thereby suppressing excessive charging in low-temperature, low-humidity environments. The migration properties of strontium titanate microparticles having Si-containing convex portions on their surfaces can be evaluated by measuring the adhesion rate, which will be described later. A higher adhesion rate indicates that the inorganic microparticles are less likely to migrate from toner particles to other components.

[0015] A preferred configuration of the toner will be described below. The proportion Sp (%) of amorphous polyester resin on the surface of the toner particles, as determined by time-of-flight secondary ion mass spectrometry, is preferably 50% or more. Having Sp of 50% or more improves the durability of the toner and facilitates electron transfer between the toner and the inorganic fine particles. To enhance the above effects, Sp is more preferably 60% or more, and even more preferably 70% or more. The abundance ratio Sp is preferably 50 to 98%, more preferably 60 to 95%, and even more preferably 70 to 92%. Sp can be controlled by the amount of amorphous polyester resin added as the shell resin.

[0016] Aluminum element content C on the surface of toner particles obtained by energy dispersive X-ray analysis Al For example, 7.0 x 10 -4 ~2.5 atomic%, 1.0×10 -3 Preferably, the content is 2.0 atomic % or less. Al is 1.0×10-3 atomi When the content is c% or more, the durability of the toner is further improved, and electrons can be easily transferred between the inorganic fine particles and the toner. Al By keeping the ratio of the toner charge to 2.0 atomic % or less, electron transfer becomes more appropriate, making it easier to maintain the charge of the toner. If the toner charge can be maintained, the amount of toner coated on the developing sleeve increases, which can increase image density.

[0017] To further enhance the above effects, Al is 3.0 x 10 -3 ~1.0 atomic% It is more preferable to use 5.0 × 10 -3 ~0.5 atomic % is even better I wish. C Al can be controlled, for example, by the amount and concentration of the aluminum-containing flocculant added.

[0018] The abundance ratio S of strontium titanate microparticles having Si-containing protrusions on the surface, calculated from the SEM observation image of the toner surface ST (area %) is, for example, 2.5 to 55.0 area %, and preferably 3.0 to 50.0 area %. ST When S is 3.0% by area or more, electrons are easily transferred to the toner particles, and excessive charging can be more easily suppressed. ST When the area ratio is 50.0% or less, electron transfer becomes more appropriate, and the charge of the toner is more easily maintained. To enhance the above effects, ST is more preferably 5.0 to 45.0 area %, and even more preferably 10.0 to 40.0 area %.

[0019] The abundance ratio S of strontium titanate microparticles having Si-containing protrusions on their surfaces ST Aluminum element content C Al The ratio value (S ST / C Al ) is, for example, 13 to 4.0 × 10 4and 20 to 2.5 × 10 4 It is preferable that S ST / C Al When the ratio of S to the aluminum element on the surface of the toner particle is 20 or more, the amount of strontium titanate fine particles having Si-containing protrusions on the surface becomes sufficient, and electron transfer occurs more easily. ST / C Al is 2.5 x 10 4 By setting the ratio to the aluminum element, the amount of strontium titanate fine particles having Si-containing protrusions on their surfaces is appropriate, making it easier to maintain the charge of the toner. To further enhance the above effects, ST / C Al is 50 to 1.5 × 10 4 More preferably, it is 100 to 0.5 × 10 4 It is more preferable that:

[0020] The powder resistivity of strontium titanate microparticles having Si-containing protrusions on the surface is, for example, 7.0 × 10 8 ~1.4×10 11 Ω cm, 1.0×10 9 ~1.0×10 11 It is preferable that the powder resistivity is 1.0×10 9 A powder resistivity of 1.0×10 Ω·cm or more makes it easier to maintain the charge of the toner. 11 By keeping the resistance at Ω·cm or less, it is easier to prevent the toner from being excessively charged.

[0021] To further enhance the above effect, the powder resistivity is set to 3.0×10 9 ~0.8×10 11 Ω·cm is more preferable, and 7.0×10 9 ~0.5×10 11 It is more preferable that the resistivity is Ω·cm. The powder resistivity of strontium titanate microparticles having Si-containing protrusions on their surfaces varies depending on the particle size of the titanium strontium microparticles, the amount of Si added during production, and the type and content of the surface treatment agent. It can be controlled more easily.

[0022] The Bragg angle of the strontium titanate microparticles having Si-containing protrusions on their surfaces is defined as Θ. In this case, in a CuKα X-ray diffraction spectrum obtained with 2Θ in the range of 10° to 90°, it is preferable that the microparticles have peaks in the ranges of 39.700°±0.150° and 46.200°±0.150°. When the area of ​​the peak at 39.700°±0.150° is defined as Sa and the area of ​​the peak at 46.200°±0.150° is defined as Sb, Sb / Sa is, for example, 1.70 to 2.40, and preferably 1.80 to 2.30.

[0023] Strontium titanate with a peak at this position has a perovskite structure belonging to the cubic crystal system, and peaks a and b in the ranges of 39.700°±0.150° and 46.200°±0.150° are diffraction peaks derived from lattice planes with Miller indices (111) and (200), respectively. Generally, particles belonging to a cubic crystal system tend to have a hexahedral shape, and strontium titanate microparticles also grow during the manufacturing process while retaining the (100) and (200) faces that correspond to the plane directions of the hexahedron. When strontium titanate microparticles with the (200) face that corresponds to the plane direction of the hexahedron and the (111) face that corresponds to the vertex direction are used, it is possible to make it difficult for the strontium titanate microparticles to migrate from the toner particles. To further enhance the above effects, Sb / Sa is more preferably 1.85 to 2.25, and even more preferably 1.90 to 2.20.

[0024] The amorphous polyester resin is preferably a condensation polymer of an acid component and an alcohol component. The content ratio U of the monomer units derived from isophthalic acid based on the total monomer units derived from the acid component in the amorphous polyester resin is iso is, for example, 50 mol % or more, and preferably 60 mol % or more. isoWhen the content of U is 60 mol % or more, the amorphous polyester resin can easily interact with the aluminum element, thereby further improving durability and making it easier to transfer electrons. iso is more preferably 80 mol % or more, and even more preferably 90 mol % or more. iso is, for example, 50 to 99 mol %, preferably 60 to 99 mol %, more preferably 80 to 98 mol %, and even more preferably 90 to 97 mol %.

[0025] In this disclosure, the term "monomer unit" refers to the reacted form of a monomer substance in a polymer. For example, in an amorphous polyester resin, one unit is defined as a unit between ester bonds. In addition, in the calculation of mole percent, one unit corresponds to one molecule. The origin of a monomer unit from a certain monomer substance can be confirmed by the fact that the structure of the monomer unit corresponds to the structure of the reacted monomer substance. The content of the monomer units derived from isophthalic acid based on all the monomer units derived from the acid component of the amorphous polyester resin is, for example, 50 to 99 mass%, preferably 60 to 99 mass%, more preferably 80 to 98 mass%, and even more preferably 90 to 97 mass%.

[0026] The toner particles preferably contain a crystalline polyester resin, which is generally a material that transfers electrons more easily than amorphous polyester, and therefore can easily suppress excessive charging in a low-temperature, low-humidity environment. A crystalline resin is a resin that has a clear endothermic peak in differential scanning calorimetry (DSC measurement). In order to enhance the above effect, the content of the crystalline polyester resin is preferably 1 part by mass or more based on 100 parts by mass of the toner, and 20 parts by mass or more based on 100 parts by mass of the toner to facilitate maintaining the charge. In order to further enhance the above-mentioned effects, the content is more preferably 3 parts by mass or more and 15 parts by mass or less.

[0027] The toner particles preferably contain at least one selected from the group consisting of dodecylbenzenesulfonic acid and dodecylbenzenesulfonate. Since the sulfonic acid moiety of dodecylbenzenesulfonic acid is likely to coordinate with aluminum elements, electron transfer inside the toner particles is more likely to occur. Examples of the salt include sodium salts and potassium salts, and a sodium salt is preferred.

[0028] The content of strontium titanate fine particles having convex portions containing Si on the surface is preferably 0.10 to 3.00 parts by mass, more preferably 0.10 to 1.20 parts by mass, and even more preferably 0.15 to 0.80 parts by mass with respect to 100 parts by mass of the toner particles.

[0029] The fixing rate of strontium titanate fine particles having convex portions containing Si on the surface in the toner is preferably 80 to 99%, more preferably 85 to 99%, and even more preferably 87 to 97%. The higher the fixing rate value, the less likely it is to transfer from the toner particles to other members.

[0030] Each component constituting the toner and the manufacturing method of the toner will be described in more detail. <Strontium titanate fine particles having convex portions containing Si on the surface> Strontium titanate fine particles having convex portions containing Si on the surface can be produced, for example, by an atmospheric pressure heating reaction method. At this time, it is preferable to use a peptized product of a hydrolyzate of a titanium compound as the titanium oxide source and a water-soluble acidic strontium source compound as the strontium source.

[0031] The strontium titanate fine particles have convex portions containing Si on the surface. Further, the convex portions are preferably formed by silica fine particles. Examples of the convex portions include convex portions formed by embedding silica fine particles and convex portions formed by fixing silica fine particles. The same effects are exhibited by both convex portions formed by embedding silica fine particles and convex portions formed by fixing silica fine particles without embedding. Note that the strontium titanate fine particles of the present disclosure are fine particles including the convex portions containing Si on the surface thereof.

[0032] The Si-containing convex portions can be formed by adding a silica-containing particle source when producing strontium titanate microparticles. This will be described in detail later. From the viewpoint of chargeability, the number-average particle diameter of the particles in the convex portions is preferably less than 5 nm. The number-average particle diameter of the particles in the convex portions is preferably 1 nm or more and less than 5 nm.

[0033] The method for forming Si-containing protrusions on the surface of strontium titanate microparticles involves mixing a mineral acid peptized product of a titanium compound hydrolysate, a strontium source, and a silica-containing particle source, and then reacting the mixture of raw materials at 60 to 100°C while adding an aqueous alkaline solution, followed by acid treatment.

[0034] The atmospheric pressure heating reaction method will be explained below. The titanium oxide source is a mineral acid peptized product of a hydrolyzed titanium compound, preferably metatitanic acid obtained by a sulfuric acid method and having an SO content of 1.0 mass % or less, more preferably 0.5 mass % or less, which is peptized with hydrochloric acid to a pH of 0.8 to 1.5.

[0035] On the other hand, as a strontium source, strontium nitrate or hydrochloride can be used. As the nitrate, for example, strontium nitrate can be used. As the hydrochloride, for example, strontium chloride can be used. The strontium titanate obtained here is The lithium fine particles have a perovskite crystal structure, which is preferable in that the environmental stability of charging is further improved.

[0036] Next, shape control will be explained. One example of a method for obtaining the shape of the strontium titanate fine particles is to carry out a dry mechanical treatment. For example, Hybridizer (manufactured by Nara Machinery Works), Nobilta (manufactured by Hosokawa Micron Corporation), Mechanofusion (manufactured by Hosokawa Micron Corporation), and Hyflex Gral (manufactured by EarthTechnica Co., Ltd.) can be used. By treating strontium titanate microparticles with these devices and adjusting the treatment time, it is easy to control the Sb / Sa ratio to between 1.80 and 2.30. The longer the treatment time, the smaller the Sb / Sa ratio, and the shorter the treatment time, the larger the Sb / Sa ratio.

[0037] When the shape of strontium titanate microparticles is controlled by mechanical treatment, fine powder of the strontium titanate microparticles may be generated. In order to remove the fine powder, it is preferable to perform acid treatment after the mechanical 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. In addition to hydrochloric acid, nitric acid, acetic acid, etc. can be used for the acid treatment. It is preferable to perform mechanical treatment to control the shape of the strontium titanate microparticles before performing surface treatment on the strontium titanate microparticles.

[0038] Examples of silica-containing particle sources include sodium silicate and silica. Addition of the silica-containing particle source can form Si-containing protrusions. It is preferable that the Si element be exposed on the surface of the Si-containing protrusions, as this will more easily counteract the positive potential of the strontium titanate portion.

[0039] The amount of silica-containing particle source added is a factor that affects the Si-containing protrusions present on the surface of strontium titanate microparticles, and this can be adjusted appropriately to obtain the desired particle size and shape. In order not to inhibit the charge leakage properties of the strontium titanate part, it is preferable that the particle size of the silica-containing particles be less than 5 nm.

[0040] As the alkaline aqueous solution, a caustic alkali can be used, but among these, an aqueous sodium hydroxide solution is preferred.

[0041] In this production method, factors that affect the particle size of the resulting strontium titanate microparticles and the Si-containing protrusions present on the surfaces of the strontium titanate microparticles include the following. These include the pH when metatitanic acid is peptized with hydrochloric acid, the mixing ratio of the titanium oxide source, the strontium source, and the silica-containing particle source, the concentration of the titanium oxide source at the start of the reaction, the concentration of the silica-containing particle source, the temperature when the alkaline aqueous solution is added, the addition rate, the reaction time, and the stirring conditions.

[0042] Furthermore, in the step of adding an alkaline aqueous solution, the half-width of the strontium titanate microparticles can be controlled by adding the solution while applying ultrasonic vibrations. In the reaction step, applying ultrasonic vibrations increases the rate of crystal precipitation, resulting in particles with a small crystallite size. In order to control the half-width, it is preferable to rapidly cool the aqueous solution after the reaction by adding the alkaline aqueous solution.

[0043] Examples of methods for rapid cooling include adding pure water cooled to 10° C. or below until the temperature reaches the desired level. Rapid cooling can prevent the crystallite size from increasing during the cooling process. In addition, if the temperature of the system is suddenly lowered by, for example, immersing the system in ice water after adding the alkaline solution to stop the reaction, the reaction can be forcibly stopped before the crystal growth reaches saturation, and the particle size distribution can be controlled. can be controlled.

[0044] Furthermore, the particle size distribution can also be controlled by making the reaction system non-uniform by reducing the stirring speed, changing the stirring method, etc. These factors can be adjusted as appropriate to obtain strontium titanate microparticles and Si-containing convex portions with the desired particle size and particle size distribution. In order to prevent the formation of carbonates during the reaction process, it is preferable to prevent contamination with carbon dioxide gas by, for example, carrying out the reaction under a nitrogen gas atmosphere.

[0045] The mixing ratio of the titanium oxide source and the strontium source during the reaction, where strontium is represented by Sr and its oxide is represented by SrO, is preferably SrO / TiO2 molar ratio of 0.90 or more and 1.40 or less, more preferably 1.05 or more and 1.20 or less.

[0046] When the SrO / TiO2 (molar ratio) is 1.00 or less, the reaction product tends to contain not only metal titanate but also unreacted titanium oxide. Because strontium has a relatively high solubility in water, while the titanium oxide source has a relatively low solubility in water, when the SrO / TiO2 (molar ratio) is 1.00 or less, the reaction product tends to contain not only metal titanate but also unreacted titanium oxide.

[0047] The concentration of the titanium oxide source at the beginning of the reaction is preferably 0.050 mol / L or more and 1.300 mol / L or less, and more preferably 0.080 mol / L or more and 1.200 mol / L or less, in terms of TiO2. By increasing the concentration of the titanium oxide source at the beginning of the reaction, the number average particle size of the primary particles of the strontium titanate microparticles can be reduced.

[0048] When adding the aqueous alkaline solution, if the temperature is 100°C or higher, a pressure vessel such as an autoclave will be required, and practically, the temperature is preferably in the range of 60°C to 100°C.

[0049] Furthermore, the slower the addition rate of the alkaline aqueous solution, the larger the particle size of the strontium titanate microparticles and the convex portions formed of silica that are obtained, whereas the faster the addition rate, the smaller the particle size of the strontium titanate microparticles and the convex portions formed of silica that are obtained. The rate of addition of the aqueous alkaline solution is preferably 0.001 to 1.2 equivalents / h, more preferably 0.002 to 1.1 equivalents / h, relative to the charged raw material. These rates can be adjusted appropriately depending on the particle size to be obtained.

[0050] In this production method, it is preferable to further acid-treat the strontium titanate microparticles obtained by the atmospheric pressure heating reaction. When producing strontium titanate microparticles by the atmospheric pressure heating reaction, if the mixing ratio of the titanium oxide source to the strontium source, SrO / TiO2 (molar ratio), exceeds 1.00, the unreacted strontium remaining after the reaction may react with carbon dioxide in the air to produce impurities such as carbonates. To facilitate uniform coating with the surface treatment agent, it is recommended to add an alkaline aqueous solution and then perform an acid treatment to remove the unreacted metal source.

[0051] In the acid treatment, the pH is preferably adjusted to 2.5 or more and 7.0 or less, more preferably 4.5 or more and 6.0 or less, using hydrochloric acid. As the acid, in addition to hydrochloric acid, nitric acid, acetic acid, etc. can be used for the acid treatment. When sulfuric acid is used, metal sulfates that have low solubility in water are likely to be generated.

[0052] The shape of the strontium titanate particles may be controlled. The strontium titanate particles are preferably cubic or rectangular. A dry mechanical treatment may be used as a method for controlling the shape.

[0053] The strontium titanate fine particles may be surface-treated with a surface treatment agent, which is not particularly limited, but may include a disilylamine compound, a halogenated silane compound, a silicone compound, or a silane coupling agent.

[0054] The disilylamine compound is a compound having a disilylamine (Si-N-Si) moiety. Examples of the disilylamine compound include hexamethyldisilazane (HMDS), N-methyl-hexamethyldisilazane, and hexamethyl-N-propyldisilazane. Examples of the halogenated silane compound include dimethyldichlorosilane.

[0055] Examples of silicone compounds include silicone oils and silicone resins (varnishes). Examples of silicone oils include dimethyl silicone oils, methylphenyl silicone oils, α-methylstyrene-modified silicone oils, chlorophenyl silicone oils, and fluorine-modified silicone oils. Examples of silicone resins (varnishes) include methyl silicone varnishes and phenylmethyl silicone varnishes.

[0056] Examples of the silane coupling agent include a silane coupling agent having an alkyl group and an alkoxy group, a silane coupling agent having an amino group and an alkoxy group, and a fluorine-containing silane coupling agent.

[0057] More specific examples of the silane coupling agent include dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, trimethylmethoxysilane, trimethyldiethoxysilane, triethylmethoxysilane, triethyldiethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, isobutyltrimethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyldimethoxymethylsilane, γ-aminopropyldiethoxymethylsilane, 3,3,3-trifluoropropyldimethoxysilane, 3,3,3-trifluoropropyldiethoxysilane, perfluorooctylethyltriethoxysilane, and 1,1,1-trifluorohexyldiethoxysilane.

[0058] The silane coupling agent is preferably a silane coupling agent having an alkyl group and an alkoxy group, such as dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, trimethylmethoxysilane, trimethyldiethoxysilane, triethylmethoxysilane, triethyldiethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, isobutyltrimethoxysilane, octyltrimethoxysilane, or octyltriethoxysilane.

[0059] Among the above silane coupling agents, those treated with propyltrimethoxysilane or isobutyltrimethoxysilane are preferred, with propyltrimethoxysilane being more preferred. The amount of the treatment agent is preferably 0.5 to 25.0 parts by mass per 100 parts by mass of the strontium titanate microparticles. The above-mentioned surface treatment agents may be used alone or in combination of two or more.

[0060] <Other inorganic fine particles> The toner may contain other inorganic fine particles in addition to the strontium titanate fine particles having Si-containing protrusions on the surface. Examples of inorganic fine particles include inorganic fine particles such as phosphate fine particles, hydrotalcite particles, and titanium oxide, and resin fine particles such as vinyl resin, polyester resin, and silicone resin. These inorganic fine particles are preferably added by applying a shear force in a dry state, for example.

[0061] <Amorphous polyester resin> The toner must contain an amorphous polyester resin on the surface of the toner particles. The amorphous polyester resin may be, for example, a resin obtained by polycondensation of a carboxylic acid component and an alcohol component as shown below.

[0062] Examples of the carboxylic acid component include terephthalic acid, isophthalic acid, phthalic acid, fumaric acid, maleic acid, cyclohexanedicarboxylic acid, and trimellitic acid. Examples of alcohol components include aliphatic diols such as ethylene glycol, 1,2-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, and neopentyl glycol; bisphenols such as bisphenol A and hydrogenated bisphenol; alkylene oxide adducts of bisphenol A such as an ethylene oxide adduct of bisphenol A and a propylene oxide adduct of bisphenol A; glycerin, trimethylolpropane, and pentaerythritol.

[0063] Of these, isophthalic acid is preferably used as described above. The carboxylic acid component preferably contains terephthalic acid and isophthalic acid. Among these, preferred alcohol components include an ethylene oxide adduct of bisphenol A, a propylene oxide adduct of bisphenol A, ethylene glycol, glycerin, etc. The alcohol component preferably contains a propylene oxide adduct of bisphenol A, or ethylene glycol.

[0064] The acid value of the amorphous polyester resin is, for example, 0 to 20 mgKOH / g. The weight-average molecular weight of the amorphous polyester resin is preferably 5,000 or more to improve durability, and is preferably 50,000 or less to improve fixability even in a low-temperature, low-humidity environment. The weight-average molecular weight is more preferably 8,000 to 15,000.

[0065] <Aluminum element> The toner must contain aluminum element on the surface of the toner particles. Specifically, the toner particles preferably contain at least one aluminum element-containing compound selected from the group consisting of aluminum chloride, polyaluminum chloride, aluminum sulfate, potassium aluminum sulfate, aluminum nitrate, aluminum lactate, etc. There is no particular limitation on the means for incorporating aluminum element into the toner particle surface. For example, when producing toner particles by an emulsion aggregation method, a compound containing aluminum element can be added as an aggregating agent, and when producing toner particles by a pulverization method, aluminum element can be incorporated into the raw material resin in advance, or aluminum element can be added when the raw materials are melt-kneaded, so that it is incorporated into the toner particles. When toner particles are produced by a wet production method such as a polymerization method, the additive may be contained in the raw materials or may be added via an aqueous medium during the production process.

[0066] <Binder resin> The binder resin for the toner is not particularly limited other than the polyester resin, and conventionally known resins can be used in combination.

[0067] Specifically, polystyrene, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer Examples of the polymerizable copolymer that can be used include styrene copolymers such as styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-octyl methacrylate copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-maleic acid copolymer, and styrene-maleic acid ester copolymer; polyacrylic acid esters; polymethacrylic acid esters; and polyvinyl acetate, and these can be used in combination.

[0068] The binder resin preferably contains a styrene-acrylic resin. The content of the styrene-acrylic resin in the binder resin is preferably 50 to 99 mass %, 60 to 98 mass %, or 80 to 97 mass %.

[0069] Examples of the styrene-acrylic resin include homopolymers made of the following polymerizable monomers, copolymers obtained by combining two or more of these, and mixtures thereof. Styrenic monomers such as styrene, α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, p-methoxystyrene and p-phenylstyrene; (meth)acrylic monomers such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-amyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, dimethyl phosphate ethyl (meth)acrylate, diethyl phosphate ethyl (meth)acrylate, dibutyl phosphate ethyl (meth)acrylate, and 2-benzoyloxyethyl (meth)acrylate, (meth)acrylonitrile, 2-hydroxyethyl (meth)acrylate, (meth)acrylic acid, and maleic acid; Vinyl ether monomers such as vinyl methyl ether and vinyl isobutyl ether; vinyl ketone monomers such as vinyl methyl ketone, vinyl ethyl ketone and vinyl isopropenyl ketone; Polyolefins such as ethylene, propylene, and butadiene.

[0070] <Release agent> The toner may contain a known wax as a release agent. Specific examples include petroleum waxes and derivatives thereof, such as paraffin wax, microcrystalline wax, and petrolatum, montan wax and derivatives thereof, hydrocarbon waxes produced by the Fischer-Tropsch process and derivatives thereof, polyolefin waxes and derivatives thereof, such as polyethylene, and natural waxes and derivatives thereof, such as carnauba wax and candelilla wax, and derivatives thereof, and derivatives thereof also include oxides, block copolymers with vinyl monomers, and graft modified products.

[0071] Other examples include alcohols such as higher aliphatic alcohols, fatty acids such as stearic acid and palmitic acid or their acid amides, esters, and ketones, hydrogenated castor oil and its derivatives, vegetable waxes, and animal waxes.These may be used alone or in combination.

[0072] Among these, when polyolefin, hydrocarbon wax produced by the Fischer-Tropsch method, or petroleum wax is used, the developability and transferability tend to be improved, and therefore it is preferable. Paraffin wax is preferred. An antioxidant may be added to these waxes to the extent that it does not affect the effects of the toner. In addition, from the viewpoint of phase separation property with respect to the binder resin or crystallization temperature, preferred examples include higher fatty acid esters such as behenyl behenate and dibehenyl sebacate. The content of the release agent is preferably 1.0 part by mass or more and 30.0 parts by mass or less with respect to 100.0 parts by mass of the binder resin.

[0073] <Coloring agent> The toner particles may contain a colorant. Known pigments and dyes can be used as the colorant. Pigments are preferred as the colorant because they have excellent weather resistance. Examples of cyan colorants include copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, and basic dye lake compounds. Specific examples include: CI Pigment Blue 1, 7, 15, 15:1, 15:2, 15:3, 15:4, 60, 62 and 66.

[0074] Examples of 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. Specific examples include CI Pigment Red 2, 3, 5, 6, 7, 23, 48:2, 48:3, 48:4, 57:1, 81:1, 122, 144, 146, 150, 166, 169, 177, 184, 185, 202, 206, 220, 221 and 254, and CI Pigment Violet 19.

[0075] Examples of yellow colorants include condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds. Specific examples include the following: CI Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 97, 109, 110, 111, 120, 127, 128, 129, 147, 151, 154, 155, 168, 174, 175, 176, 180, 181, 185, 191 and 194.

[0076] Examples of black colorants include those toned to black using the above yellow, magenta, and cyan colorants, as well as carbon black and magnetic materials. These colorants can be used alone or in mixtures, or in the form of a solid solution. The colorant is preferably used in an amount of 1.0 to 20.0 parts by mass per 100.0 parts by mass of binder resin. When using a magnetic material in an aqueous medium as described below, a hydrophobic treatment can be performed to stably incorporate the magnetic material into the resin.

[0077] <Toner manufacturing method> The method for producing the toner is not particularly limited, and any known method can be used, such as a pulverization method, a suspension polymerization method, a solution suspension method, an emulsion aggregation method, a dispersion polymerization method, etc. Any production method can be applied to obtain the toner. Hereinafter, a detailed description will be given of a method for producing toner particles by emulsion aggregation.

[0078] (Dispersion liquid preparation process) The binder resin particle dispersion liquid is prepared, for example, as follows. When the binder resin is a resin other than a vinyl resin, such as a polyester resin, the resin is mixed with an aqueous medium in which an ionic surfactant or a polymer electrolyte is dissolved. Thereafter, this solution is heated to a temperature above the melting point or softening point of the resin to dissolve it, and the binder resin particles are dispersed in an aqueous medium containing an ionic surfactant using a dispersing machine with a strong shear force such as a homogenizer. A dispersion liquid is prepared by dispersing the particles.

[0079] When the binder resin is a homopolymer or copolymer (vinyl resin) of a vinyl monomer such as a styrene-acrylic resin, the vinyl monomer may be subjected to emulsion polymerization or seed polymerization in an ionic surfactant, thereby preparing a dispersion liquid in which vinyl resin particles are dispersed in an aqueous medium containing an ionic surfactant. The dispersion means is not particularly limited, and examples thereof include known dispersion devices such as a rotary shear homogenizer, a ball mill having media, a sand mill, and a dyno mill.

[0080] A phase inversion emulsification method may also be used to prepare the dispersion. In the phase inversion emulsification method, a binder resin is dissolved in an organic solvent, and a neutralizer and / or dispersion stabilizer are added as needed. An aqueous solvent is added dropwise under stirring to obtain emulsified particles, and the organic solvent is then removed from the resin dispersion to obtain the emulsion. The order in which the neutralizer and / or dispersion stabilizer are added may be changed. The number-average particle diameter of the binder resin particles is typically 1 μm or less, preferably 0.01 μm to 1.00 μm. A number-average particle diameter of 1.00 μm or less ensures a favorable particle size distribution for the final toner, and inhibits the generation of free particles. Furthermore, a number-average particle diameter within the above range reduces uneven distribution of toner particles, improves dispersion within the toner, and reduces variations in performance and reliability. When the toner particles contain a crystalline polyester resin, the crystalline polyester resin particle dispersion can also be obtained by the above-mentioned method.

[0081] In the emulsion aggregation method, a colorant particle dispersion can be used as needed. The colorant particle dispersion is prepared by dispersing at least colorant particles in a dispersant. The number-average particle diameter of the colorant particles is preferably 0.5 μm or less, more preferably 0.2 μm or less. When the number-average particle diameter is 0.5 μm or less, diffuse reflection of visible light can be prevented, and the binder resin particles and colorant particles can be easily aggregated in the aggregation process. When the number-average particle diameter is within the above range, uneven distribution between toner particles is reduced, dispersion within the toner is improved, and variations in performance and reliability are reduced.

[0082] In the emulsion aggregation method, a wax particle dispersion can be used as needed. The wax particle dispersion is prepared by dispersing at least wax particles in a dispersant. The number-average particle diameter of the wax particles is preferably 2.0 μm or less, more preferably 1.0 μm or less. When the number-average particle diameter is 2.0 μm or less, the wax content is less uneven among toner particles, resulting in good long-term image stability. When the number-average particle diameter is within the above range, uneven distribution among toner particles is reduced, dispersion within the toner is good, and variations in performance and reliability are reduced.

[0083] The combination of colorant particles, binder resin particles, and wax particles is not particularly limited and can be freely selected as appropriate depending on the purpose. In addition to the above dispersion, other particle dispersions obtained by dispersing appropriately selected particles in a dispersant may be further mixed. The particles contained in the other particle dispersions are not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include internal additive particles, charge control agent particles, inorganic particles, and abrasive particles. These particles may be dispersed in the binder resin particle dispersion or the colorant particle dispersion.

[0084] Examples of dispersants contained in binder resin particle dispersions, colorant particle dispersions, wax particle dispersions, and other particle dispersions include aqueous media containing polar surfactants. Examples of aqueous media include water such as distilled water and ion-exchanged water, and alcohols. These may be used alone or in combination of two or more. The content of the polar surfactant cannot be generally defined, and should be selected appropriately depending on the purpose. can be done.

[0085] Examples of polar surfactants include anionic surfactants such as sulfate salts, sulfonates, phosphate esters, and soaps; and cationic surfactants such as amine salts and quaternary ammonium salts. Specific examples of anionic surfactants include sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, sodium alkylnaphthalenesulfonate, and sodium dialkylsulfosuccinate. Specific examples of cationic surfactants include alkylbenzenedimethylammonium chloride, alkyltrimethylammonium chloride, and distearylammonium chloride. Among these, sulfonate surfactants are preferably used in the present disclosure, as described above. These surfactants may be used alone or in combination of two or more.

[0086] These polar surfactants can also be used in combination with non-polar surfactants, such as polyethylene glycol-based, alkylphenol ethylene oxide adduct-based, and polyhydric alcohol-based nonionic surfactants.

[0087] The content of the colorant particles is preferably 0.1 to 30 parts by mass relative to 100 parts by mass of the binder resin in the aggregated particle dispersion when the aggregated particles are formed. The content of the wax particles is preferably 0.5 to 25 parts by mass, more preferably 5 to 20 parts by mass, relative to 100 parts by mass of the binder resin in the aggregated particle dispersion when the aggregated particles are formed.

[0088] Furthermore, in order to more precisely control the chargeability of the resulting toner, charge control particles and binder resin particles may be added after the aggregated particles are formed. The particle sizes of the binder resin particles, colorant particles, and other particles are measured using a laser diffraction / scattering particle size distribution measuring device LA-960V2 manufactured by Horiba, Ltd.

[0089] (Agglutination process) The aggregation step of forming aggregated particles is a step of forming aggregated particles containing binder resin particles, and optionally added colorant particles and wax particles, etc., in an aqueous medium containing binder resin particles, and optionally added colorant particles and wax particles, etc.

[0090] The aggregated particles can be formed in an aqueous medium by, for example, adding a pH adjuster, an aggregating agent, and a stabilizer to the aqueous medium, mixing the mixture, and then applying appropriate temperature, mechanical power, etc. to the mixture. Examples of pH adjusters include alkalis such as ammonia and sodium hydroxide, and acids such as nitric acid and citric acid. Examples of flocculants include monovalent metal salts such as sodium and potassium, divalent metal salts such as calcium and magnesium, trivalent metal salts such as iron and aluminum, and alcohols such as methanol, ethanol, and propanol.

[0091] The stabilizer may be a polar surfactant itself or an aqueous medium containing the same. For example, when the polar surfactant contained in each particle dispersion is anionic, a cationic stabilizer may be selected.

[0092] The addition and mixing of the flocculant and the like is preferably carried out at a temperature equal to or lower than the glass transition temperature of the resin contained in the aqueous medium. When mixing is carried out under these temperature conditions, the flocculation proceeds in a stable state. Mixing can be carried out using, for example, a known mixing device, homogenizer, mixer, etc.

[0093] In the aggregation step, a dispersion containing an amorphous polyester resin is applied to the surface of the aggregated particles to form a coating layer (shell layer), thereby forming a core particle having a shell layer on the surface of the core particle. Toner particles having a core / shell structure can be obtained. That is, the toner particles preferably have a shell containing an amorphous polyester resin on the surface of the core particles. The amorphous polyester resin shell makes it easier for the amorphous polyester resin to be present on the surface of the toner particles. The core particles preferably contain a styrene-acrylic resin. The amount of the shell is preferably 1.5 to 10 parts by mass, more preferably 2 to 6 parts by mass, per 100 parts by mass of the core particles. The aggregation step may be repeated multiple times in stages.

[0094] (fusion process) The fusion process is a process in which the obtained aggregated particles are heated to fuse them. Before the fusion process, a pH adjuster, a polar surfactant, a non-polar surfactant, etc. may be added as appropriate to prevent fusion between toner particles. The heating temperature may be from the glass transition temperature of the resin contained in the aggregated particles (if two or more types of resins are used, the glass transition temperature of the resin with the highest glass transition temperature) to the decomposition temperature of the resin.

[0095] Therefore, the heating temperature varies depending on the type of resin in the binder resin particles and cannot be generally specified, but is generally from the glass transition temperature of the resin contained in the aggregated particles to 140° C. Heating can be carried out using a known heating device or tool.

[0096] The fusion time is short if the heating temperature is high, and long if the heating temperature is low. In other words, the fusion time cannot be generally determined because it depends on the heating temperature, but it is generally between 30 minutes and 10 hours. The toner particles obtained through the above steps can be separated into solid and liquid by a known method, and the toner particles can be recovered, and then washed, dried, etc. under appropriate conditions.

[0097] (External addition process) Toner can be obtained by adding inorganic fine particles such as strontium titanate fine particles having Si-containing protrusions on their surfaces to the obtained toner particles. Other external additives may be added as needed. From the viewpoint of the dispersibility of the external additives, the mixing time in the external addition step is preferably adjusted to a range of 5 to 30 minutes, more preferably 8 to 20 minutes.

[0098] [Methods for measuring each physical property] Next, the measurement methods for each physical property will be described. (Method of separating each material from toner) The materials contained in the toner can be separated from the toner by utilizing the difference in solubility in the solvent of each material. First separation: The toner is dissolved in methyl ethyl ketone (MEK) at 23°C, and the soluble matter (amorphous polyester resin, styrene acrylic resin) is separated from the insoluble matter (crystalline polyester resin, wax, colorant, inorganic fine particles, etc.). Second separation: The insoluble matter obtained in the first separation (crystalline polyester resin, wax, colorant, inorganic fine particles, etc.) is dissolved in MEK at 100°C, and the soluble matter (crystalline polyester resin, wax) is separated from the insoluble matter (colorant, inorganic fine particles, etc.). Third separation: The soluble matter (crystalline polyester resin, wax) obtained in the second separation is dissolved in chloroform at 23°C, and the soluble matter (crystalline polyester resin) is separated from the insoluble matter (wax). Fourth separation: The soluble fraction (amorphous polyester resin, styrene-acrylic resin) obtained in the first separation is dissolved in a mixed solution of methyl ethyl ketone (MEK) and toluene at 23°C, and the soluble fraction (styrene-acrylic resin) and insoluble fraction (amorphous polyester resin) are separated.

[0099] <Monomer analysis of amorphous polyester resin components> The types of monomers in the amorphous polyester resin components are analyzed using a pyrolysis GC / MS device under the following conditions for samples of each resin component separated from the toner. The types of constituent compounds are identified by analyzing the mass spectrum of the components of the resin decomposition products that are produced when the resin is pyrolyzed at 550°C to 700°C. The specific measurement conditions are as follows: Measuring device: "Voyager" (product name, manufactured by Thermo Electron) Pyrolysis temperature: 600℃ Column: HP-1 (15 m x 0.25 mm x 0.25 μm) Inlet: 300℃, Split: 20.0 Injection volume: 1.2mL / min Temperature rise: 50℃ (4 min) - 300℃ (20℃ / min)

[0100] <Method for measuring the proportion Sp of amorphous polyester resin on the toner particle surface> The abundance ratio Sp of the amorphous polyester resin on the toner particle surface is measured using toner particles from which inorganic fine particles have been separated by a method for isolating strontium titanate fine particles having Si-containing protrusions on the surface, which will be described later. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) is used for the measurements. TRIFT-IV manufactured by ULVAC-PHI, Inc. is used to measure the fragment ions of amorphous polyester resin. The analysis conditions are as follows. Sample preparation: Adhering toner particles to an indium sheet Primary ions: Au ions Accelerating voltage: 30 kV Charge neutralization mode: On Measurement mode: Positive Raster: 200 μm Measurement time: 60 seconds According to ULVAC-PHI's standard software (Win Cadence), The total count number of mass numbers identified in the monomer analysis of the polyester resin is taken as the ion amount (secondary ion mass / secondary ion charge number (m / z)), and this value is divided by the total ion amount counted in the toner measurement, and the result is multiplied by 100 to obtain the abundance rate Sp (%) of the amorphous polyester resin.

[0101] <Content ratio of monomer units derived from isophthalic acid U iso Quantitative method for Regarding the monomers identified by the monomer analysis of the amorphous polyester resin, the composition ratio of each monomer can be determined by performing composition analysis of the amorphous polyester resin by NMR. Composition analysis by NMR can be carried out as follows. Nuclear magnetic resonance spectroscopy ( 1 The composition of the amorphous polyester resin is analyzed using H-NMR [400 MHz, CDCl3, temperature (60°C)]. Measuring device: FT NMR device JNM-EX400 (manufactured by JEOL Ltd.) Measurement frequency: 400MHz Pulse condition: 5.0 μs Frequency range: 10500Hz Accumulation count: 64 times

[0102] In addition, nuclear magnetic resonance spectroscopy ( 13 The composition of the amorphous polyester resin is analyzed using C-NMR [400 MHz, CDCl3 (TMS 0.05%), temperature (40°C)]. Measuring device: FT NMR device JNM-EX400 (manufactured by JEOL Ltd.) Measurement frequency: 400MHz Pulse condition: 5.0 μs Frequency range: 10500Hz Accumulation count: 16 times From the mass profile of the secondary ion mass / secondary ion charge number (m / z) obtained, the composition ratio of the monomers of the monomer species identified by the above-mentioned monomer analysis is determined.

[0103] <Content of aluminum element on the toner particle surface C Al Measurement method> Using a transmission electron microscope (TEM), the content of polyvalent metals is measured from an electron image of the cross section of a toner particle by the following method. The measurement sample was prepared by mixing toner particles with a visible light-curing embedding resin (D-800, manufactured by Nissin EM Co., Ltd.), pressurizing the mixture into a disk shape with a diameter of 7.9 mm and a thickness of 1.0±0.3 mm using a tablet press at 25°C. The pressurization was carried out at 35 MPa for 60 seconds. A thin sample with a thickness of 100 nm was then cut from the sample using an ultramicrotome (EM UC7, manufactured by Leica) equipped with a diamond blade at a cutting speed of 0.6 mm / s.

[0104] This sample is magnified 200,000 times using a transmission electron microscope (TEM) (JEM2800 model: manufactured by JEOL Ltd.) under conditions of an acceleration voltage of 200 keV and an electron beam probe size of 1 mm, and the cross section of the toner particle is observed at a major axis of ±10% of the weight average particle diameter (D4) of the toner particle to be observed. Next, the constituent elements of the cross section of the obtained toner particles are analyzed by collecting a spectrum using an energy dispersive X-ray dispersion method (EDS: NSS Thermo electron). Mapping of the toner cross section is performed under the following conditions.

[0105] (STEM-EDS elemental mapping image acquisition conditions) A STEM-EDS elemental mapping image is acquired in the same field of view as the SEI image observation field. EDS detector: JEOL Ltd. JED-2300T Dry SD100GV detector (detector element area: 100 mm 2 ) EDS analyzer: Thermo Fisher Scientific NORAN System7 Drift correction coefficient: 2 Dwell Time: 30 μs Number of integrations: 100 frames X-ray CountRate: 4000 - 10000 cps Element mapping image size: 256 × 256 pixels

[0106] The collected spectral mapping data was used to extract a quantitative map image using the quantitative map mode in the measurement command of the above-mentioned NORAN System7. At that time, the setting values were as follows. · Kernel size: 3 × 3 · Quantitative map setting: High (slow) · Filter fit type: High precision (slow) Next, 1000 pixels are extracted in the range of 5 nm in the vertical direction from the surface of the toner particles. The EDS spectra of the extracted pixels are added together.

[0107] Quantitative analysis was performed on the obtained spectrum by the Cliff-Lorimer method to calculate the aluminum element content C Al (atomic%). C Al (atomic%) is the atomic weight fraction when the total elements detected during analysis are set to 100%. The above measurement was carried out on the cross-sections of 20 toner particles, and the arithmetic mean value was adopted.

[0108] <The abundance ratio S of strontium titanate fine particles having a convex part containing <Si> on the surface ST (area product%) measurement method> Regarding the toner, an EDX device (manufactured by Horiba, Ltd., EMAX Evolution X-Max (80 mm 2An image was taken at a magnification of 40,000 using a scanning electron microscope (SEM) (manufactured by Hitachi High-Technologies, S-4800) equipped with ( )). Based on EDX analysis, more than 300 strontium titanate microparticles having convex portions containing Si on the surface were identified from within a single field of view based on the presence of Ti and Sr. The SEM was observed at an acceleration voltage of 15 kV, an emission current of 20 μA, and WD 15 mm, and the EDX analysis was performed under the same conditions with a detection time of 60 minutes. The criterion for determining whether the selected microparticles are strontium titanate microparticles having convex portions containing Si on the surface is whether there are convex portions containing Si as shown below. For the strontium titanate microparticles having convex portions containing Si on the surface that were identified, the abundance ratio S ST (area %) of strontium titanate microparticles having convex portions containing Si on the surface of the toner was determined using the area analysis tool of image processing and analysis software WinRoof (Miyaya Shoko Co., Ltd.).

[0109] <Method for Isolating Strontium Titanate Microparticles Having Convex Portions Containing Si on the Surface> When measuring the physical properties of strontium titanate microparticles having convex portions containing Si on the surface, other external additives, and toner particles from toner to which strontium titanate microparticles having convex portions containing Si on the surface are externally added, the strontium titanate microparticles having convex portions containing Si on the surface and other external additives can be separated from the toner and measured. The toner is ultrasonically dispersed in methanol to remove strontium titanate microparticles having convex portions containing Si on the surface and other external additives, and then left standing for 24 hours. The ultrasonic dispersion is performed for 60 minutes at a frequency of 20 kHz and an output of 30 W. The sedimented toner particles and the strontium titanate microparticles having convex portions containing Si on the surface and other external additives dispersed in the supernatant are separated, recovered, and dried sufficiently to isolate the toner particles. Also, the supernatant can be processed by centrifugation to isolate strontium titanate microparticles having convex portions containing Si on the surface.

[0110] <Measurement Method for Number-Average Particle Size of Convex Portions Containing Si> The number-average particle size of the primary particles of the convex portions containing Si is measured using a transmission electron microscope (TEM) "JEM2800" (manufactured by JEOL Ltd.). The strontium titanate fine particles separated by the above-described procedure can be used. First, prepare the measurement sample. For 5 mg of the strontium titanate fine particles to be measured, add 1 mL of isopropanol and disperse it for 5 minutes using an ultrasonic disperser (ultrasonic cleaner). Next, prepare the measurement sample by dropping 1 drop of the above dispersion liquid onto a microgrid with a support film for TEM (150 mesh) and drying it.

[0111] Next, using a transmission electron microscope (TEM), under the condition of an acceleration voltage of 200 kV, acquire an image at a magnification (e.g., 200k to 1M times) at which the convex portions in the field of view can be sufficiently measured in length, and measure the particle sizes of 100 randomly selected convex portions to obtain the number-average particle size. The measurement of the particle size is performed using image processing software "Image-Pro Plus ver.4.0" (manufactured by Media Cybernetics).

[0112] The convex portions containing Si are determined by performing secondary electron image (SEI) observation and EDS mapping measurement of the strontium titanate fine particles separated by the above-described method using a transmission electron microscope (TEM) "JEM2800" (manufactured by JEOL Ltd.). In the EDS mapping measurement, by using a silicon drift detector having a large detection element area, EDS mapping can be measured with high sensitivity. The conditions are shown below.

[0113] (Image Acquisition Conditions) Mode: STEM observation mode Acceleration voltage: 200 kV Magnification: 1,000,000 times Probe size: 1 nm Detector: Secondary electron detector (SEI detector) SEI image size: 1024×1024 pixels

[0114] (STEM-EDS elemental mapping image acquisition conditions) A STEM-EDS elemental mapping image is acquired in the same field of view as the SEI image observation field. EDS detector: JEOL JED-2300T dry SD100GV detector (detector area: 100 mm 2 ) EDS analyzer: Thermo Fisher Scientific NORAN System 7 Drift correction factor: 2 Dwell Time: 30 μs Accumulation count: 100 frames X-ray CountRate:4000~10000cps Elemental mapping image size: 256 x 256 pixels Quantitative map images were extracted from the collected spectral mapping data using the quantitative map mode in the measurement command of the NORAN System 7. The settings were as follows: Kernel size: 3×3 Quantitative map setting: High (slow) Filter Fit Type: High Precision (Slow)

[0115] First, a morphology image of the strontium titanate microparticle is acquired. Then, EDS elemental quantitative mapping images of Si and Sr elements are acquired at the same position and at the same magnification, and these EDS elemental mapping images are then overlaid. In the area where the Si mapping and Sr mapping overlap, it is difficult to precisely separate the Si-containing portion. On the other hand, in the outer periphery of the strontium titanate microparticle, there is an area where only Si is mapped outside the Sr mapping area, so the Si-containing portion can be clearly identified. In the outer periphery where Si is confirmed to be contained, convex portions are identified from the previously acquired morphology image. In the convex portion observed in the Si-containing outer periphery, a straight line is drawn connecting the valleys at both ends of the convex portion, and in this case, a convex portion is defined as a convex portion where the distance between the apex of the convex and the line is 1 nm or more. The length of the line connecting the valleys at both ends of the convex portion is the particle size of the convex portion.

[0116] <Measurement of Powder Resistivity of Strontium Titanate Fine Particles Having Convex Portions Containing Si on the Surface> The resistance of strontium titanate fine particles having convex portions containing Si on the surface is measured using the measuring device schematically shown in FIGS. 1A and 1B. When measuring a sample, after leaving it in an environment of 23°C and 50% RH for 24 hours, the measurement is carried out. The resistance measurement cell A is composed of a cylindrical PTFE resin container 15 with a hole having a cross-sectional area of 2.4 cm 2 , a lower electrode (made of stainless steel) 16, a support pedestal (made of PTFE resin) 17, and an upper electrode (made of stainless steel) 18. Place the cylindrical PTFE resin container 15 on the support pedestal 17, fill it with 0.7 g of the sample 19, place the upper electrode 18 on the filled sample 19, and measure the thickness of the sample. Let the thickness without the sample in advance be D1 (blank) (FIG. 1A), the actual thickness d of the sample when filled with 0.7 g, and the thickness D2 (sample) when the sample is filled (FIG. 1B). Then, the thickness d of the sample is expressed by the following formula. d = D2 (sample) - D1 (blank)

[0117] Then, by applying a voltage between the electrodes and measuring the current flowing at that time, the resistivity can be obtained. For the measurement, an electrometer 20 (Keithley 6517, manufactured by Keithley Instruments) and a computer 21 for control are used. The measurement conditions are that the contact area S between the sample and the electrode is 2.4 cm 2 , and the load on the upper electrode is 230 g. The voltage application condition is to use the IEEE-488 interface for control between the control computer and the electrometer, utilize the automatic range function of the electrometer, and perform screening by applying voltages of 1V, 2V, 4V, 8V, 16V, 32V, 64V, 128V, 256V, 512V, 1000V for 1 second each. At that time, the electrometer determines whether it is possible to apply up to a maximum of 1000V (for example, in the case of a sample thickness of 1.00 mm, the electric field strength is 10000V / cm). If an overcurrent flows, "VOLTAGE SOURCE OPERATE" blinks. Then, the applied voltage is lowered, and the applicable voltage is further screened to automatically determine the maximum value of the applied voltage. After that, this measurement is carried out.

[0118] Measure the resistance value from the current value after holding the voltage obtained by dividing the maximum voltage value into five equal parts for 30 seconds at each step. For example, when the maximum applied voltage is 1000V, apply the voltage in the order of increasing and then decreasing in steps of 200V, which is 1 / 5 of the maximum applied voltage, i.e., 200V (first step), 400V (second step), 600V (third step), 800V (fourth step), 1000V (fifth step), 1000V (sixth step), 800V (seventh step), 600V (eighth step), 400V (ninth step), 200V (tenth step). Measure the resistance value from the current value after holding for 30 seconds at each step. By processing this with a computer, calculate the electric field strength and specific resistance and plot them on a graph. Read the specific resistance at an electric field strength of 1000V / cm from the plot. The specific resistance and electric field strength are obtained by the following formulas. Specific resistance (Ω·cm) = (Applied voltage (V) / Measured current (A)) × S (cm 2 ) / d (cm) Electric field strength (V / cm) = Applied voltage (V) / d (cm)

[0119] <Measurement of the weight average particle size (D4) of toner particles> The weight average particle size (D4) of toner particles is measured with a precision particle size distribution measuring device "Coulter Counter Multisizer 3" (registered trademark, manufactured by Beckman Coulter, Inc.) equipped with a 100μm aperture tube, and the attached dedicated software "Beckman Coulter Multisizer 3 Version3.51" (manufactured by Beckman Coulter, Inc.) for setting measurement conditions and analyzing measurement data. Measure with an effective measurement channel number of 25,000 channels, analyze the measurement data, and calculate.

[0120] <Method for measuring the Bragg angle Θ of strontium titanate fine particles having convex portions containing Si on the surface> The Bragg angle Θ of the inorganic fine particles is measured using a powder X-ray diffractometer "SmartLab" (manufactured by Rigaku Corporation, a sample horizontal type high-power X-ray diffractometer). The Sb / Sa ratio is calculated from the peaks obtained using the analytical software "PDXL2 (version 2.2.2.0)" that comes with the above-mentioned device. The measurement sample is a toner or strontium titanate fine particles isolated from the toner, and the measurement is carried out according to the following procedure: In the following examples, the measurement is carried out on the produced strontium titanate fine particles.

[0121] (Sample preparation) The measurement sample is uniformly placed in a 0.5 mm diameter Boro-Silicate capillary (manufactured by W. Muller) and then measured.

[0122] (Measurement conditions) ·Tube:Cu ·Optical system: CBO-E Sample stage: Capillary sample stage Detector: D / tex Ultra250 detector Voltage: 45kV ·Current: 200mA ·Starting angle: 10° End angle: 90° Sampling width: 0.02° Speed ​​measurement time setting value: 10 IS:1mm RS1: 20mm RS2: 20mm Attenuator: Open Capillary rotation speed setting: 100 For other conditions, the initial settings of the device are used.

[0123] (analysis) First, the obtained peaks are separated using the software "PDXL2" that comes with the instrument. Peak separation is performed by performing optimization using the "split Voigt function" that can be selected in PDXL, and the obtained integrated intensity values ​​are used. Thus, the value of 2Θ at the diffraction peak top and its area are determined. Sb / Sa is calculated from the peak area at a predetermined 2Θ value. At this time, if there is a large deviation between the calculation result of peak separation and the measured spectrum, perform processing such as manually setting the baseline to adjust so that the calculation result and the measured spectrum match.

[0124] <Method for Identification and Quantification of Dodecylbenzenesulfonic Acid Component> For the measurement of the dodecylbenzenesulfonic acid component contained in toner particles, measurement was performed under the following conditions using a thermal desorption gas chromatograph with a mass spectrometer, TRACE2000CG / MS manufactured by ThermoQuest. Extraction condition 120.0 °C Sample amount 1.0 g Column 0.32 mm capillary column For each peak in the obtained analysis results, components derived from the raw materials of dodecylbenzenesulfonic acid were analyzed and identified from the mass spectrum. Next, a plurality of diluted concentrations of dodecylbenzenesulfonic acid were adjusted to create a calibration curve. Then, the quantification of the dodecylbenzenesulfonic acid component was performed from the peak height of the dodecylbenzenesulfonic acid component in the analysis results and the calibration curve.

[0125] <Method for Evaluating the Adhesion Rate of Strontium Titanate Fine Particles Having Convex Portions Containing Si on the Surface> The adhesion rate of strontium titanate fine particles having convex portions containing Si on the surface can be measured by the following method. The higher the value of the adhesion rate, the more difficult it is for strontium titanate fine particles having convex portions containing Si on the surface to migrate to other members. First, prepare two types of samples (toner before water washing, toner after water washing).

[0126] (i) Toner before water washing: Use various toners prepared in the examples described later as they are.

[0127] (ii) Toner after washing: Add 160 g of sucrose (Kishida Chemical) to 100 mL of ion-exchanged water and dissolve in a hot water bath to prepare a concentrated sucrose solution. Add 31 g of the concentrated sucrose solution and Contaminon N (a nonionic surfactant, anionic surfactant) to a centrifuge tube. 6 mL of a 10% by mass aqueous solution of a neutral detergent for cleaning precision measuring instruments (manufactured by Wako Pure Chemical Industries, Ltd.) containing an organic builder and having a pH of 7 is added to prepare a dispersion. Add 1g of toner to this dispersion and break up any clumps of toner with a spatula or similar. Place the centrifuge tube in a shaker (AS-1N AS ONE Corporation) for 5.8 seconds. -1 , 20 After shaking, the solution was transferred to a glass tube (50 mL) for a swing rotor and centrifuged in a Front Lab FLD2012 (manufactured by AS ONE Corporation) for 58.3 s. -1 Centrifuge for 30 minutes. Visually check that the toner and aqueous solution are sufficiently separated, and collect the toner that has separated to the top layer with a spatula. After filtering the collected aqueous solution containing the toner with a vacuum filter, dry it in a dryer for at least 1 hour to use as a sample.

[0128] For these samples before and after washing, wavelength dispersive X-ray fluorescence analysis (XRF) is used to quantify the amount of strontium titanate microparticles having Si-containing protrusions on their surface by using the intensity of the target element (e.g., Sr), and the adhesion rate is determined.

[0129] The measurement samples were prepared by placing 1 g of toner after washing and 1 g of toner before washing in a dedicated aluminum ring for pressing, flattening it, and then pressing it at 20 MPa for 60 seconds using a tablet molding compressor "BRE-32" (manufactured by Maekawa Testing Machinery Manufacturing Co., Ltd.) to form pellets with a thickness of approximately 2 mm.

[0130] The measurement equipment used was a wavelength-dispersive X-ray fluorescence analyzer "Axios" (PANalytical) and the accompanying dedicated software "SuperQ ver. 4.0F" (PANalytical) for setting measurement conditions and analyzing measurement data. Rh was used as the anode of the X-ray tube, the measurement atmosphere was vacuum, the measurement diameter (collimator mask diameter) was 10 mm, and the measurement time was 10 seconds. Light elements were measured using a proportional counter (PC), and heavy elements were measured using a scintillation counter (SC). Measurements were performed under the above conditions, and elements were identified based on the peak positions of the obtained X-rays. Their concentrations were then calculated from the counting rate (unit: cps), which is the number of X-ray photons per unit time.

[0131] The migration rate from the toner is calculated by first determining the elemental strength of the toner before and after washing using the above method, and then calculating the migration rate based on the following formula. Adhesion rate of strontium titanate microparticles having Si-containing protrusions on the surface=(Sr element strength of toner after water washing) / (Sr element strength of toner before water washing)×100 [Example]

[0132] The present disclosure will be described in more detail below with reference to examples, but these examples are not intended to limit the present disclosure in any way. Unless otherwise specified, the number of parts in the following formulations indicates parts by mass.

[0133] <Production Example of Strontium Titanate Microparticles A1 (Strontium Titanate Microparticles A1 Having Si-Containing Protrusions on Their Surfaces)> Metatitanic acid produced by the sulfuric acid method was deironized and bleached, then desulfurized by adding a 3 mol / L aqueous solution of sodium hydroxide to adjust the pH to 9.0, and then neutralized to pH 5.6 with 5 mol / L hydrochloric acid, filtered, and washed with water. Water was added to the washed cake to make a 1.90 mol / L slurry in terms of TiO2, and hydrochloric acid was added to adjust the pH to 1.4, which was then subjected to peptization. After desulfurization and peptization, 1.90 moles of metatitanic acid was collected in terms of TiO2 and placed in a 3 L reaction vessel. 2.185 moles of strontium chloride aqueous solution was added to the peptized metatitanic acid slurry so that the SrO / TiO2 (molar ratio) was 1.15, and the TiO2 concentration was then adjusted to 1.039 moles / L. Next, sodium silicate was added so that the amount of Si added was equivalent to 5.0 mol % relative to strontium. An aqueous sodium hydroxide solution was prepared and heated to 90°C with stirring, and then 440 mL of a 10 mol / L aqueous sodium hydroxide solution was added over 55 minutes under ultrasonic vibration.

[0134] After that, stirring was continued at 95°C for 45 minutes, and then the mixture was poured into ice water to rapidly cool it down and terminate the reaction. The reaction slurry was heated to 70°C, and 12 mol / L hydrochloric acid was added until the pH reached 5.0. Stirring was continued for 1 hour, and the resulting precipitate was washed by decantation. After separation by filtration, it was dried in the air at 120°C for 8 hours. Next, 300 g of the dried product was placed in a dry particle compositer (Nobilta NOB-130, manufactured by Hosokawa Micron). Treatment was performed for 10 minutes at a treatment temperature of 30°C with a rotary treatment blade at 90 m / sec. Hydrochloric acid was further 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 hydrochloric acid was added to adjust the pH to 2.5.

[0135] Next, 13% by mass of propyltrimethoxysilane based on the solid content was added after stirring for 2 hours, and the mixture was then stirred for 10 hours. A 5N sodium hydroxide solution was added to adjust the pH to 6.5, and stirring was continued for 1 hour. After filtration and washing, the resulting cake was dried in air at 120°C for 8 hours. The resulting strontium titanate microparticles were designated strontium titanate microparticles A1, which have Si-containing protrusions on their surfaces. On the surface of the strontium titanate microparticles A1 having Si-containing protrusions on their surface, silica particles were partially embedded or the protrusions were formed by the adhered silica particles. The particle size of the silica particles forming the protrusions was 4 nm.

[0136] <Production Examples of Strontium Titanate Microparticles A2 to A10> In the production example of strontium titanate microparticles A1, the amount of sodium silicate aqueous solution, the amount of surface treatment (amount of propyltrimethoxysilane), and the treatment time in the dry particle composite device were changed as shown in Table 1 to obtain strontium titanate microparticles A2 to A10. On the surface of the strontium titanate microparticles A2 to A9 (strontium titanate microparticles A2 to A9 having Si-containing protrusions on the surface), some silica particles were buried, or protrusions formed by adhering silica particles were present. The particle size of the silica particles forming the protrusions was less than 5 nm. No Si-containing protrusions were present on the surface of the strontium titanate microparticles A10.

[0137] <Production Example of Amorphous Polyester Resin D1> 100 parts by mass of a mixture of raw material monomers mixed in the charging ratios shown in Table 2 and 0.55 parts by mass of tin di(2-ethylhexanoate) as a catalyst were placed in a 6-liter four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple, and reacted under a nitrogen atmosphere at 200°C for 6 hours. The reaction was carried out under a reduced pressure of 40 kPa and continued until the weight-average molecular weight (Mw) reached 12,000. The resulting amorphous polyester resin is designated amorphous polyester resin D1.

[0138] <Production Examples of Amorphous Polyester Resins D2 to D5> Amorphous polyester resins D2 to D5 were obtained in the same manner as in the production example of amorphous polyester resin D1, except that the raw material monomers were changed as shown in Table 2.

[0139] <Amorphous polyester resin particle dispersions D1 to D5> The amorphous polyester resin D1 was transferred in a molten state to a Cavitron CD1010 (manufactured by Eurotech) at a rate of 100 g per minute. At the same time, a separately prepared ammonia water with a concentration of 0.37% by mass was heated to 120°C in a heat exchanger and transferred to the Cavitron CD1010 at a rate of 0.1 L per minute. The rotor rotation speed was 60 Hz, and the pressure was 5 kg / cm. 2 The Cavitron CD1010 was operated under the conditions of A resin particle dispersion liquid in which resin particles of the polyester resin were dispersed was obtained. Ion-exchanged water was added to the resin particle dispersion liquid to adjust the solid content to 20 mass % to obtain amorphous polyester resin particle dispersion liquid D1. In addition, amorphous polyester resin particle dispersions D2 to D5 were obtained in the same manner except that the amorphous polyester resin D1 was changed to D2 to D5.

[0140] <Production Example of Toner Particle 1> (Preparation of styrene acrylic resin particle dispersion) Styrene: 75 parts n-Butyl acrylate: 25 parts The above materials were mixed and dissolved, and a solution of 1.0 part of anionic surfactant (Dowfax, manufactured by The Dow Chemical Company) dissolved in 60 parts of ion-exchanged water was added to the mixture, followed by dispersion and emulsification in a flask to prepare a monomer emulsion. Next, 2.0 parts of sodium dodecylbenzenesulfonate were dissolved in 90 parts of ion-exchanged water, to which 2.0 parts of the monomer emulsion was added, and then 10 parts of ion-exchanged water in which 1.0 part of ammonium persulfate had been dissolved was added.

[0141] The remainder of the monomer emulsion was then added over 3 hours, and the flask was purged with nitrogen. The solution in the flask was then heated to 65°C in an oil bath while stirring, and emulsion polymerization was continued for 5 hours to obtain a styrene-acrylic resin particle dispersion. The solid content of the styrene-acrylic resin particle dispersion was adjusted to 20% by mass by adding ion-exchanged water.

[0142] (Preparation of Colorant Particle Dispersion) Cyan pigment (Dainichi Seika Chemicals Co., Ltd., CI Pigment Blue 15:3) 35 parts Sodium dodecylbenzenesulfonate 2.0 parts 250 parts ion-exchanged water The above ingredients were mixed, dissolved, and dispersed for about an hour using a high-pressure impact disperser, Ultimizer (HJP30006, manufactured by Sugino Machine Co., Ltd.), to obtain a colorant particle dispersion. The volume average particle diameter D50v of the particles in this colorant particle dispersion was 150 nm. Ion-exchange water was then added to adjust the solids concentration to 20% by mass.

[0143] (Preparation of Release Agent Particle Dispersion) 200 parts paraffin wax (Nippon Seiro Co., Ltd., HNP-9) Sodium dodecylbenzenesulfonate 10.0 parts 20.0 parts ion-exchanged water The above materials were mixed and the release agent was dissolved in a pressure discharge homogenizer (Gaulin Homogenizer manufactured by Gaulin Co., Ltd.) at an internal liquid temperature of 120°C, after which the mixture was subjected to dispersion treatment at a dispersion pressure of 5 MPa for 120 minutes and then at 40 MPa for 360 minutes, and then cooled to obtain a dispersion liquid. Ion-exchanged water was added to adjust the solid content to 20 mass%, and this was used as a release agent particle dispersion liquid.

[0144] <Preparation of Crystalline Polyester Resin Particle Dispersion> 1,10-dodecanedioic acid: 225 parts 1,6-Hexanediol: 143 parts The above materials were charged into a reaction vessel equipped with a stirrer, nitrogen inlet tube, temperature sensor, and distillation column. The temperature was raised to 160°C over 1 hour, and 0.8 parts by mass of dibutyltin oxide was added. The temperature was raised to 180°C over 6 hours while distilling off the produced water, and the dehydration condensation reaction was continued for 5 hours while maintaining the temperature at 180°C. The temperature was then gradually raised to 230°C under reduced pressure, and stirring was continued for 2 hours while maintaining the temperature at 230°C. The reaction product was then cooled. After cooling, solid-liquid separation was performed, and the solid was dried to obtain a crystalline polyester resin.

[0145] Crystalline polyester resin: 100 parts Methyl ethyl ketone: 40 parts Isopropyl alcohol: 30 parts 10% ammonia solution: 6 parts The above materials were added to a 3-liter jacketed reactor (Tokyo Rikakikai Co., Ltd.: BJ-30N) equipped with a condenser, thermometer, water dripper, and anchor blade. The resin was dissolved by stirring at 100 rpm while maintaining the temperature at 80°C in a water-circulating thermostatic bath. The water-circulating thermostatic bath was then set to 50°C, and a total of 400 parts of ion-exchanged water maintained at 50°C was added dropwise at a rate of 7 parts by mass / min to induce phase inversion, yielding an emulsion. 576 parts by mass of the resulting emulsion and 500 parts by mass of ion-exchanged water were placed in a 2-liter recovery flask and placed in an evaporator (Tokyo Rikakikai Co., Ltd.) equipped with a vacuum control unit via a trap bulb. The recovery flask was heated in a 60°C hot water bath while rotating, and the pressure was reduced to 7 kPa, taking care to avoid bumping, to remove the solvent. The volume average particle size (D50v) of the resin particles in this dispersion was 185 nm. Thereafter, ion-exchanged water was added to obtain a crystalline polyester resin particle dispersion liquid with a solid content concentration of 22.1% by mass.

[0146] (Toner particle production) Styrene acrylic resin particle dispersion 375 parts Colorant particle dispersion 75 parts Release agent particle dispersion 15 parts Crystalline polyester resin particle dispersion 33.9 parts 750 parts ion-exchanged water Sodium dodecylbenzenesulfonate 3.2 parts The above material was placed in a 3-liter reaction vessel equipped with a thermometer, pH meter, and stirrer as the core forming material, and 1.0% nitric acid was added at 25°C to adjust the pH to 3.0. After that, 100 parts of a 2.0% by mass aluminum chloride aqueous solution was added as a flocculant while dispersing at 5,000 rpm using a homogenizer (Ultra Turrax T50 manufactured by IKA), and the mixture was dispersed for 6 minutes.

[0147] The mixture was then heated to 53°C in a heating water bath using a stirring blade while adjusting the rotation speed as needed to stir the mixture. The volume average particle size of the formed aggregated particles was measured using a Coulter Multisizer III. When the volume average particle size reached 5.0 μm, the temperature was maintained and 1:18.75 parts of an amorphous polyester resin particle dispersion was added as a shell layer forming material over 5 minutes. After maintaining the temperature at 50°C for 30 minutes, the temperature was increased to 90°C while adjusting the pH to 9.0, and the mixture was maintained at 90°C.

[0148] Hydrochloric acid was then added to adjust the pH to 5.0 at 90°C, and the mixture was stirred for an additional 30 minutes. A 0.9 mol / L Na2CO3 aqueous solution was then added, and the pH was adjusted to 5.5, and the mixture was maintained for 30 minutes. The mixture was then cooled to 25°C, filtered, and subjected to solid-liquid separation, followed by washing with ion-exchanged water. After washing, the mixture was dried in a vacuum dryer to obtain toner particles 1 with a weight-average particle diameter of 7.3 μm.

[0149] <Toner 1 manufacturing example> Strontium titanate fine particles A1 (0.50 parts) and silica fine particles (RY200 manufactured by Nippon Aerosil Co., Ltd.) (0.8 parts) were externally added and mixed with 100.0 parts of toner particles 1 using an FM10C (manufactured by Nippon Coke & Engineering Co., Ltd.). The external addition conditions were as follows: the lower blade was set to A0 blade, the gap to the deflector wall was set to 20 mm, the amount of toner particles charged was 2.0 kg, and the rotation speed was 66.6 s. -1 The external addition time was 10 minutes, and the cooling water temperature was 20°C and the flow rate was 10 L / min. Thereafter, the mixture was sieved through a mesh having an opening of 200 μm to obtain Toner 1.

[0150] <Production examples of toners 2 to 37> Toners 2 to 37 were obtained in the same manner as in the production example of Toner 1, except that in the production example of Toner 1, the type and number of parts added of strontium titanate microparticles, the type and number of parts added of amorphous polyester resin, the number of parts added of crystalline polyester resin particle dispersion, the concentration of aluminum chloride added, and the type of surfactant were changed as shown in Table 3.

[0151] <Examples 1 to 34, Comparative Examples 1 to 3> Toners 1 to 37 were used to carry out the following evaluations. For the actual evaluation, an HP LaserJet Enterprise M609dn was used with its process speed modified to 410 mm / sec. The evaluation paper was Vitality (Xerox, basis weight 75 g / m 2 , letter size) was used.

[0152] <Evaluation of image streaks> Image streaks are vertical streaks of about 0.5 mm that occur when toner breaks down due to friction inside the cartridge during long-term printing, and are an image defect that is easily observed when outputting a full-page halftone image. A modified LBP712Ci (Canon) was used as the image forming apparatus. The process speed of the main body was modified to 250 mm / sec. Necessary adjustments were made to enable image formation under these conditions. The toner was removed from the black and cyan cartridges and replaced with 50 g of the toner to be evaluated. The toner loading amount was 1.0 mg / cm. 2 It was decided.

[0153] The image streaks observed during continuous use in a low-temperature, low-humidity environment (10°C, 10% RH) were evaluated. 2 ) was used. In a low temperature and humidity environment (10°C / 10%RH), 20,000 sheets were printed intermittently, with two E-letter images printed every four seconds at a printing rate of 1%, and then a 50% halftone image was printed across the entire surface.The presence or absence of streaks was observed, and an evaluation rank for image streaks was assigned.The evaluation results are shown in Table 4. (Evaluation criteria for image streaks) A: No streaks or toner clumps occurred. B: There are no spot-like streaks, but there are one or two small clumps of toner. C: There are 1 or 2 spot-like streaks on the edge or 3 or 4 small toner clumps. D: There are 1 or 2 spot-like streaks across the entire surface, or 5 or 6 small toner clumps.

[0154] <Evaluation of image density difference> For image evaluation regarding negative ghost, a band of a solid black image was output for one revolution of the developing sleeve in a low temperature and low humidity environment (10° C. / 10% RH), and then a halftone image was output. The evaluation method was to measure the difference in reflection density between the areas of a single print image where a solid black image was formed in the first rotation (black printed areas) and the areas where no solid black image was formed (non-image areas) on the second rotation of the developing sleeve using a Macbeth densitometer and calculate the following formula: In the image printed on the second rotation of the developing sleeve, the image density of the areas that were black printed on the first rotation of the developing sleeve is lower than the image density of the areas that were non-image areas on the first rotation of the developing sleeve, and the shape of the pattern printed on the first rotation is likely to appear as is. The density difference here was evaluated based on the difference in reflection density. "Reflection density difference" = {Reflection density (reflection density of the image in the non-image area on the first rotation of the developing sleeve)} - {Reflection density (reflection density of the image in the black printed area on the first rotation of the developing sleeve)} The smaller the difference in reflection density, the higher the image quality is evaluated. The reflection density difference was evaluated according to the following criteria, and the results are shown in Table 4. (Evaluation criteria) A: 0.00 or more and less than 0.10 B: 0.10 or more and less than 0.15 C: 0.15 or more and less than 0.20 D:0.20 or more

[0155] <Toner complex elastic modulus G * (50℃) measurement method> The hardness of the toner is the complex modulus of elasticity G at 50°C. * (50℃) G at 50℃ * The larger the value, the less streaks will occur in the toner even in a long-term durability test using a high-speed machine. The measuring device used is a rotating plate type rheometer "ARES" (manufactured by TA INSTRUMENTS). The measurement sample is prepared by weighing 0.1 g of toner and press-molding it into a disk shape with a diameter of 8.0 mm and a thickness of 1.5±0.3 mm using a tablet press at room temperature (25° C.). The sample is mounted on a parallel plate with a diameter of 8.0 mm, heated from room temperature (25°C) to 100°C over 5 minutes, held for 3 minutes, and cooled to 25°C over 10 minutes. The sample is then held at 25°C for 30 minutes before starting measurement. At this time, the sample is set so that the initial normal force is 0. As described below, the influence of the normal force can be canceled out in subsequent measurements by turning on the auto tension adjustment (Auto Tension Adjustment). Measurements are performed under the following conditions.

[0156] (1) Use parallel plates with a diameter of 8.0 mm. (2) Frequency: 1 Hz. (3) The initial applied strain (Strain) is set to 0.05%. (4) Measurements are performed in the temperature range of 25°C to 60°C at a temperature ramp rate of 2.0°C / min. Measurements are performed under the following auto-adjustment mode settings: Measurements are performed in auto-strain mode. (5) Set the maximum applied strain to 20.0%. (6) Set the maximum torque (Max Allowed Torque) to 200.0 [g·cm] and the minimum torque (Min Allowed Torque) to 0.2 [g·cm]. (7) Set the strain adjustment to 20.0% of the current strain. The measurement is performed in the auto tension adjustment mode. (8) Set Auto Tension Direction to Compression. (9) Set the Initial Static Force to 10g and the Auto Tension Sensitivity to 10.0g. (10) The operating conditions of the auto tension are: Sample Modulus: 1.00 x 10 6 Pa or more. Under the above conditions, the complex modulus of elasticity G at 50°C when measured at a frequency of 1 Hz * asked for.

[0157] <Charge leakage evaluation in low temperature and low humidity environment> The evaluation toner and a specified carrier (Japan Imaging Society standard carrier, spherical carrier N-01 with surface-treated ferrite core) were left to stand in a low-temperature, low-humidity environment of 10°C / 10%RH for more than 24 hours. Next, 9.5g of the carrier and 0.5g of the toner were placed in a 100mL plastic bottle with a lid, and shaken for 300 seconds in a shaker (YS(26) LD, manufactured by Yayoi Co., Ltd.) at a speed of 4 reciprocating movements per second to charge the developer consisting of the toner and carrier. Next, the amount of triboelectric charge was measured using a device for measuring the amount of triboelectric charge shown in Figure 2. About 0.5 to 1.5 g of the developer was placed in a metal measuring container 2 having a 500 mesh screen 3 at the bottom. The toner was placed inside the container and covered with a metal lid 4. The mass of the entire measurement container at this time was defined as W1 (g). Next, suction was performed from suction port 7 using suction device 1 (at least the part in contact with measurement container 2 is an insulator) by adjusting air flow control valve 6 so that the pressure on vacuum gauge 5 was 250 mmAq. Suction was performed in this state for 2 minutes, and the toner was removed by suction. The potential on electrometer 9 at the end of suction was defined as V (volts). Here, 8 is a capacitor with a capacity of C (μF), and the entire measurement container after suction was weighed and defined as W2 (g). The amount of triboelectric charge of this toner is calculated using the following formula: Amount of triboelectric charge of sample (mC / kg) = C × V / (W1-W2)

[0158] The sample was left standing in the shaker for another 300 seconds, and the same measurement was carried out. The smaller the ratio of the amount of triboelectric charge after standing to the amount of triboelectric charge before standing, the better the leak resistance of the toner. The charge leak resistance was evaluated according to the following criteria based on the value of (amount of triboelectric charge after standing) / (amount of triboelectric charge before standing)×100. [Evaluation criteria] A: Less than 50% B: 50% or more but less than 60% C: 60% or more but less than 70% D: 70% or more but less than 80% Excellent charge leakage in this evaluation indicates that electrons can be easily transmitted even in low-temperature, low-humidity environments. When electrons are easily transmitted, the difference in charge between the first and second weeks of the sleeve in the low-concentration evaluation is small, making low concentration less likely to occur.

[0159] In Examples 1 to 34, good results were obtained in all evaluation items. On the other hand, in Comparative Examples 1 to 3, the results were inferior to those of the Examples in the evaluation item of image density difference. Furthermore, in Comparative Example 1, the results were inferior to those of the Examples in the evaluation of image streaks.

[0160] From the above results, according to the present disclosure, it is possible to provide a toner that achieves stable image density even in a low-temperature, low-humidity environment.

[0161] [Table 1]

[0162] [Table 2]

[0163] [Table 3] In the table, TiSr fine particles A refers to "strontium titanate fine particles A." APES dispersion refers to an amorphous polyester resin particle dispersion. CPES dispersion refers to a crystalline polyester resin particle dispersion. SDBS stands for sodium dodecylbenzenesulfonate. BuNSS stands for butylnaphthalene. Sodium phthalenesulfonate. The adhesion rate indicates the adhesion rate of strontium titanate fine particles having Si-containing protrusions on the surface in the toner.

[0164] [Table 4]

[0165] The present disclosure relates to the following configurations. (Configuration 1) A toner containing toner particles and inorganic fine particles, the inorganic fine particles contain strontium titanate fine particles, The strontium titanate microparticles have Si-containing protrusions on the surface thereof, The toner is characterized in that the toner contains an amorphous polyester resin and an aluminum element on the surface of the toner particles. (Configuration 2) 2. The toner according to claim 1, wherein the abundance ratio Sp (%) of the amorphous polyester resin on the surface of the toner particles is 50% or more, as determined by time-of-flight secondary ion mass spectrometry. (Configuration 3) the content C of the aluminum element on the surface of the toner particle obtained by energy dispersive X-ray analysis Al (atomic%) is 1.0×10 -3 ~2.0 atomic% 3. The toner according to claim 1 or 2. (Configuration 4) The abundance ratio S of the strontium titanate fine particles calculated from the SEM observation image of the toner surface ST 4. The toner according to any one of configurations 1 to 3, wherein (area %) is 3.0 to 50.0 area %. (Configuration 5) The abundance ratio S of the strontium titanate fine particles calculated from the SEM observation image of the toner surface ST(area %) of the aluminum element content C obtained by energy dispersive X-ray analysis on the surface of the toner particles Al (atomic%) ratio (S ST / C Al ) is 20 to 2.5 × 10 4 5. The toner according to any one of configurations 1 to 4, wherein: (Configuration 6) The powder resistivity of the strontium titanate fine particles is 1.0 × 10 9 ~1.0×10 11 6. The toner according to any one of configurations 1 to 5, wherein the toner has a viscosity of Ω·cm. (Configuration 7) When the Bragg angle of the strontium titanate microparticles is Θ, in a CuKα X-ray diffraction spectrum obtained in a range of 2Θ from 10° to 90°, (i) A diffraction peak a originating from the lattice plane of Miller index (111) exists in the range of 39.700°±0.150°, (ii) A diffraction peak b originating from the lattice plane of Miller index (200) exists in the range of 46.200°±0.150°, (iii) the area of ​​the diffraction peak a is Sa, When the area of ​​the diffraction peak is Sb, 7. The toner according to any one of configurations 1 to 6, wherein Sb / Sa is 1.80 to 2.30. (Configuration 8) The content ratio U of the monomer units derived from isophthalic acid based on the total monomer units derived from acid components in the amorphous polyester resin iso 8. The toner according to any one of configurations 1 to 7, wherein (mol %) is 60 mol % or more. (Configuration 9) Said U iso 9. The toner according to claim 8, wherein the amount of the hydroxyl group is 90 mol % or more. (Configuration 10) 10. The toner according to any one of configurations 1 to 9, wherein the toner particles contain a crystalline polyester resin. (Configuration 11) 11. The toner according to any one of configurations 1 to 10, wherein the toner particles contain at least one selected from the group consisting of dodecylbenzenesulfonic acid and dodecylbenzenesulfonic acid salts. (Configuration 12) 12. The toner according to any one of Configurations 1 to 11, wherein the convex portions are formed of silica fine particles.

Claims

1. A toner containing toner particles and inorganic fine particles, the inorganic fine particles contain strontium titanate fine particles, The strontium titanate microparticles have Si-containing convex portions on their surfaces, The toner is characterized in that the toner contains an amorphous polyester resin and an aluminum element on the surface of the toner particles.

2. 2. The toner according to claim 1, wherein the abundance ratio Sp (%) of the amorphous polyester resin on the surface of the toner particles is 50% or more, as determined by time-of-flight secondary ion mass spectrometry.

3. the content C of the aluminum element on the surface of the toner particle obtained by energy dispersive X-ray analysis Ａｌ (atomic%) is 1.0 x 10 -３ ~2.0 atomic% The toner according to claim 1 or 2.

4. The abundance ratio S of the strontium titanate fine particles calculated from the SEM observation image of the toner surface ＳＴ 3. The toner according to claim 1, wherein the area % is 3.0 to 50.0 area %.

5. The abundance ratio S of the strontium titanate fine particles calculated from the SEM observation image of the toner surface ＳＴ (area %) of the aluminum element content C obtained by energy dispersive X-ray analysis on the surface of the toner particles Ａｌ (atomic%) ratio (S ＳＴ / C Ａｌ ) is 20 to 2.5 x 10 ４ 3. The toner according to claim 1, wherein

6. The powder resistivity of the strontium titanate fine particles is 1.0 × 10 ９ ~1.0 x 10 １１ 3. The toner according to claim 1, wherein the toner has a viscosity of Ω·cm.

7. When the Bragg angle of the strontium titanate microparticles is Θ, in a CuKα X-ray diffraction spectrum obtained in a range of 2Θ from 10° to 90°, (i) a diffraction peak a resulting from a lattice plane with Miller indices (111) is present in the range of 39.700°±0.150°; (ii) a diffraction peak b originating from the lattice plane of Miller index (200) exists in the range of 46.200°±0.150°; (iii) the area of ​​the diffraction peak a is Sa, When the area of ​​the diffraction peak b is Sb, 3. The toner according to claim 1, wherein Sb / Sa is 1.80 to 2.

30.

8. The content ratio U of the monomer units derived from isophthalic acid based on the total monomer units derived from acid components in the amorphous polyester resin ｉｓｏ 3. The toner according to claim 1, wherein (mol %) is 60 mol % or more.

9. Said U ｉｓｏ The toner according to claim 8, wherein the amount of the hydroxyl group is 90 mol % or more.

10. The toner according to claim 1 or 2, wherein the toner particles contain a crystalline polyester resin.

11. 3. The toner according to claim 1, wherein the toner particles contain at least one selected from the group consisting of dodecylbenzenesulfonic acid and dodecylbenzenesulfonate salts.

12. The toner according to claim 1 , wherein the convex portions are formed of silica fine particles.

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