TONER

Abstract

A toner contains toner particles and an external additive on the surfaces of the toner particles. The external additive comprises composite particles, including particles A containing an organic silicon compound with siloxane linkages as a binder component, particles B that are at least partially embedded in the surfaces of particles A with an average embedding rate of 30% to 90%, and particles C containing titanium oxide or titanium acid compounds with a specific volume resistivity of 2.0 × 10⁹ to 2.0 × 10¹³ Ω·cm and a number-averaged primary particle diameter of 10 to 100 nm. The organic silicon compound contains bifunctional, trifunctional, and tetrafunctional silane monomers with specific relationships.The number-averaged primary particle diameter X of the composite fine particles and the number-averaged primary particle diameter Y of the fine particles C satisfy 1.0 ≤ X / Y ≤ 10.0.

Description

BACKGROUNDField of InterestThe present disclosure relates to a toner used in electrophotographic processes, electrostatic recording processes, electrostatic printing processes and the like.Description of Related ArtFull-color electrophotographic copiers are widely used and have begun to become accepted in the printing market. In the printing market, a high image quality and a high stability and a high printing speed are increasingly required.In order to improve the image quality, the charging properties of the toner should be stabilized. In order to stabilize the charging properties of toners, various studies on external additives have been conducted. For example, Japanese Patent Publication No. 2022-28076 discloses a toner externally added with a titanium-based compound having low resistance to reduce the possibility of excessive charging while reducing the occurrence of fogging in continuous discharge.The charge stability of toner depends on the properties of the charge applying members such as the developing roller and the carrier as well as the properties of the toner. The charge applying members come into contact with the toner to apply the charge to the toner. Therefore, components of the toner may adhere to the charge applying members.When a titanium-based compound having a low resistance as described in Japanese Patent Publication No. 2022-28076 adheres to a charge applying member, the ability of the member to apply charge to the toner is lowered. Particularly, when the charging characteristics deteriorate in high-temperature and high-humidity environments where triboelectrification is less likely, electrostatic adhesion between the charge applying members and the toner decreases.When the printing speed increases with the demand for higher speed, the toner may easily separate from the charge applying members and scatter, whereby the interior of the apparatus may be soiled. Moreover, as the amount of charge decreases, dot reproducibility for faithfully reproducing latent images, which is important for improving image quality, deteriorates.Further improvements are required to reduce the overcharge of the toner and to improve dot reproducibility while at the same time reducing toner scattering over a long period of time, even in high-temperature and high-humidity environments.SHORT DISPLAYAccordingly, the present disclosure provides a toner containing toner particles and an external additive on the surface of the toner particles. The external additive includes composite fine particles and fine particles C containing either titanium oxide fine particles or titanic acid compound fine particles and having a volume resistivity of 2.0×10 9 Ω·cm to 2.0×10 13 Ω·cm and a number-average primary particle diameter of 10 nm to 100 nm. The composite fine particles include fine particles A containing an organic silicon compound having siloxane bonds as a binder component and fine particles B located on the surfaces of the composite fine particles in a state of being at least partially embedded in the surfaces of the fine particles A. The fine particles A satisfy the following relations (1) to (3): and wherein Pa represents the proportion of silicon atoms expressed as Si a, in the structure represented by the following unit (a) relative to silicon atoms contained in the organic silicon compound as a whole, Pb represents the proportion of silicon atoms expressed as Si b, in the structure represented by the following unit (b) relative to silicon atoms contained in the organic silicon compound as a whole, and Pc represents the proportion of silicon atoms expressed as Si c, in the structure represented by the following unit (c) relative to the total silicon atoms contained in the organic silicon compound: wherein R 1 and R 2 each represent an alkyl group having 1 to 6 carbon atoms.The average embedding rate of the fine particles B in the fine particles A represented by the following equation is 30% to 90%: the number-average primary particle diameter X of the composite fine particles and the number-average primary particle diameter Y of the fine particles C satisfy the relationship: 1.0≤X / Y≤10.0.Other features of the present disclosure will become apparent from the following description of exemplary embodiments.DESCRIPTION OF THE EMBODIMENTSIn the present specification, numerical ranges expressed as "in the range of ** to ××" or "** to ××" respectively include the lower and upper limits that are the values at the ends of the range, unless otherwise specified. The toner disclosed herein includes toner particles and an external additive for the toner, and in the following description, the toner particles are also referred to as "toner base particles". Features of the Present DisclosureThe reasons for the effectiveness of the inventive concept disclosed herein are as follows, according to the inventors' view.In order to reduce the overcharge of the toner and improve the image quality, titanium oxide or titanic acid compound fine particles (fine particles C) having a volume resistivity of 2.0×10 9 Ω·cm to 2.0×10 13 Ω·cm, and a number average primary particle diameter of 10 nm to 100 nm should be externally added. This external addition provides a sharp charge distribution and high quality images.However, when the titanium oxide or titanic acid compound fine particles accumulate on the charge applying members such as the developing roller and the carrier over a longer period of time, the accumulated fine particles interfere with triboelectrification between the toner and the charge applying members, thereby degrading image quality and scattering the toner.The present inventors conducted a diligent study to reduce the contamination of charge applying members and found that the external addition of the composite fine particles disclosed herein together with the fine particles C reduces the overcharge of the toner over a long period of time to improve the image quality and reduces the scattering of the toner over a long period of time even in high-temperature and high-humidity environments, enabling a consistently high image quality.The composite fine particles are an external additive including fine particles A whose surface has protrusions resulting from the presence of fine particles B. When the average embedding rate of the fine particles B into the fine particles A is 30% to 90%, the protrusions are likely to come into contact with the fine particles C more, and thus, the fine particles C adhering to the charge applying members are effectively scraped off.However, the abreasing effect is not sufficiently produced by only the protrusions of the composite fine particles, and the relationship between the particle size of the composite fine particles and the fine particles C is important.More specifically, the number average primary particle diameter X of the composite fine particles and the number average diameter Y of the fine particles C must satisfy the relationship: 1.0≤X / Y≤10.0.When X / Y is in such a range, the contamination of the charge applying elements by titanium oxide or titanic acid compound fine particles can be effectively reduced, so that the scattering of the toner over a long period of time can be reduced even in high-temperature and high-humidity environments, enabling a constantly high image quality. From the viewpoint of producing the above-described effects, it is desirable to satisfy 2.4≤X / Y≤6.0.Moreover, the composite fine particles include fine particles A containing an organic silicon compound having siloxane bonds as a binder component.The composite fine particles also include, on their surfaces, fine particles B at least partially embedded in the surfaces of the fine particles A.The fine particles A must satisfy the following relationships (1) to (3): andIn the relationships, Pa represents the proportion of silicon atoms expressed as Si a, in the structure represented by the following unit (a) relative to the total silicon atoms contained in the organic silicon compound, Pb represents the proportion of silicon atoms expressed as Si b, in the structure represented by the following unit (b) relative to the total silicon atoms contained in the organic silicon compound, and Pc represents the proportion of silicon atoms expressed as Si c, in the structure represented by the following unit (c) relative to the silicon atoms contained in the organic silicon compound as a whole. ( R 1 and R 2 each represent an alkyl group having 1 to 6 carbon atoms).The composite fine particles containing a compound having such a composition are difficult to break when the toner is loaded by the carrier or other members, and have moderate flexibility that prevents the composite fine particles from being embedded in the toner and allows them to maintain their effectiveness on the toner surface. Consequently, the composite fine particles produce the effect of scraping the fine particles C adhering to the charge applying members even after a long period of use in high-temperature and high-humidity environments, thereby reducing the overcharge of the toner to improve the image quality and reducing the scattering of the toner in high-temperature and high-humidity environments over a long period of time.External additiveThe structure and method for preparing the external additive disclosed herein will now be described in detail. Composite fine particlesFor the contents Pa, Pb, and Pc of the above-mentioned units (a), (b), and (c) in the composite fine particles, Pb+Pc may be 0.55 or more, and Pa / (Pa+ Pb+Pc) may be 0.45 or less in order to prevent the composite fine particles from being embedded in the toner. These proportions can be controlled by the addition amount of alkoxysilane having the respective structures.The number-average primary particle diameter of the composite fine particles may be 0.03 μm to 0.30 μm, for example, 0.06 μm to 0.30 μm. When the number-average primary particle diameter is in such a range, the external additive composed of fine particles can uniformly cover the toner particles. In addition, the fine particles C are likely to be scraped off.The number-average primary particle diameter of the composite fine particles can be increased by lowering the reaction temperature, shortening the reaction time, or increasing the amount of catalyst in the hydrolysis and condensation steps. Also, the number-average primary particle diameter of the composite fine particles can be reduced by increasing the reaction temperature, extending the reaction time, or reducing the amount of catalyst in the hydrolysis and condensation steps.The fine particles B are at least partially embedded in the surfaces of the fine particles A, and the average embedding rate is 30% to 90%. The embedding rate of the fine particles B can be controlled by the time and temperature of the reaction with alkoxysilane having the above-mentioned structures (a) to (c). In order to reduce the embedding rate, the time or temperature of the reaction between alkoxysilane and fine particles B can be reduced. In order to increase the embedding rate, the time or temperature of the reaction between alkoxysilane and fine particles B may be increased.When fine particles containing an organic silicon compound having siloxane bonds as a binder component but having no protrusions derived from the presence of the fine particles B are used as the external additive of the toner, the desired protrusion-derived abating effect cannot be produced and accordingly the contamination of the charge applying parts cannot be reduced. Fine particles containing an organic silicon compound as a binder component in which fine particles B are completely embedded are an example of fine particles without protrusions. Such fine particles cannot reduce the contamination of the charge-applying elements for the same reason.The methods for measuring the above-mentioned physical properties will be described later.Production MethodThe composite fine particles disclosed herein can be produced by a sol-gel method by the hydrolysis and condensation polymerization of a silicon compound (silane monomer), but are not limited thereto. For example, a mixture of bifunctional silane having two siloxane bonds and tetra-functional silane having four siloxane bonds may be subjected to hydrolysis and condensation polymerization, and the resulting system is allowed to react with colloidal silica or the like corresponding to fine particles B to form composite fine particles. Silane monomers including bifunctional silane and tetra-functional silane will be described later. The proportion of bifunctional silane may be 30 mol% to 70 mol%, for example 40 mol% to 60 mol%. The proportion of tetra-functional silane may be 30 to 80 mol %, e.g. 40 to 70 mol %.The composite fine particles disclosed herein include, as a main component, particles containing an organic silicon compound having siloxane bonds as the binder (fine particles A).The organic silicon compound disclosed herein can be prepared by any method without limitation. For example, a silane compound dropped in water is subjected to hydrolysis and condensation in the presence of a catalyst, and the resulting suspension is filtered and dried to obtain an organic silicon compound. The size of the particles can be controlled by varying the type and amount of catalyst, the temperature at which the reaction begins, the time of dropping, and other factors. Examples of catalysts include, but are not limited to, acidic catalysts such as hydrochloric acid, hydrofluoric acid, sulfuric acid, and nitric acid, as well as basic catalysts such as ammonia water, sodium hydroxide, and potassium hydroxide.In some embodiments, the organic silicon compound used herein is prepared by the following method. More specifically, the method may include a first step of preparing a hydrolyzate of a silicon compound, a second step of mixing the hydrolyzate, an alkaline aqueous medium and colloidal silica for a polycondensation reaction of the hydrolyzate and a subsequent reaction with colloidal silica, and a third step of mixing the polycondensation product with an aqueous solution to form particles.In some cases, a hydrophobicizing agent may be additionally added.In the first step, an acidic or alkaline material acting as a catalyst is dissolved in water, and in this solution, a silicon compound is contacted with the catalyst by stirring, mixing or the like. Any known catalyst may be used. Examples of the catalyst include acidic catalysts such as acetic acid, hydrochloric acid, hydrofluoric acid, sulfuric acid and nitric acid, and basic catalysts such as ammonia water, sodium hydroxide and potassium hydroxide.The amount of the catalyst can be adjusted according to the kind of the silicon compound and the catalyst. It may be, for example, 1×10 -3 parts by mass to 1 part by mass based on 100 parts by mass of the water used for the hydrolysis of the silicon compound.When the amount of the catalyst is 1×10 -3 parts by mass or more, the reaction sufficiently proceeds. When the catalyst amount is 1 part by mass or less, the concentration of the catalyst remaining as an impurity in the fine particles is decreased, which facilitates the hydrolysis. The amount of water may be 2 moles to 15 moles per mole of silicon compound. When the amount of water is 2 mol or more, hydrolysis sufficiently proceeds, and when 15 mol or less, productivity increases.The reaction may be carried out at room temperature or with heating, but is not limited thereto. In some embodiments, the reaction temperature is maintained at 10° C. to 60° C. from the viewpoint of obtaining a hydrolyzate in a short time and reducing partial condensation of the hydrolyzate. The reaction time is not particularly limited, and can be determined in consideration of the reactivity of the silicon compound to be used, the composition of the reaction liquid containing the silicon compound, the acid and the water, and the productivity as needed.In the second step of the method for producing the particles of organic silicon compounds, the raw material solution obtained in the first step is mixed with an alkaline aqueous medium for polycondensation reaction of the particle precursor to obtain a polycondensed liquid. The alkaline aqueous medium is prepared by mixing an alkaline component, water and optionally an organic solvent and the like.The alkaline component used in the alkaline aqueous medium, which is a substance whose aqueous solution is basic, acts as a neutralizer for the catalyst used in the first step and as a catalyst for the polycondensation reaction in the second step. Examples of the alkaline component include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide, ammonia and organic amines such as monomethylamine and dimethylamine.The amount of the alkaline component is determined so that the alkaline component can neutralize the acid and effectively act as a catalyst for the polycondensation reaction. When ammonia is used as the alkaline component, for example, 0.01 to 12.5 parts by mass of ammonia is used based on 100 parts by mass of the mixture of water and organic solvent.In the second step, besides the alkaline component and water, an organic solvent may also be used for preparing the alkaline aqueous medium. Any organic solvent may be used as long as it is compatible with water. However, organic solvents which dissolve at room temperature and under normal pressure in 100 g of at least 10 g of water are suitable.Such organic solvents include, in particular, alcohols such as methanol, ethanol, n-propanol, 2-propanol and butanol; polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, glycerol, trimethylolpropane and hexanetriol; and ethers such as ethylene glycol monoethyl ether, acetone, diethyl ether, tetrahydrofuran and diacetone alcohol; and amide compounds such as dimethylformamide, dimethylacetamide and N-methylpyrrolidone.Among these organic solvents, alcohols such as methanol, ethanol, 2-propanol and butanol may be advantageous. In some embodiments, with respect to hydrolysis and dehydration condensation reactions, the same alcohol as the alcohol produced by elimination is used as the organic solvent.In the third step, the polycondensation product obtained in the second step is mixed with an aqueous solution to form particles. The aqueous solution may be water (tap water, pure water, etc.), and other water-compatible components such as a salt, an acid, an alkali, an organic solvent, a surfactant, a water-soluble polymer may be added to the water. The temperature of the polycondensed liquid and the aqueous solution in mixing may be, but is not limited to, 5° C. to 70° C. in view of the composition thereof and productivity.For collecting the resulting particles, any known method can be used without particular limitation. Thus, the particles can be collected, for example, by scooping suspended powder or by filtration. Filtration may be advantageous because of its ease of handling. Filtration may be performed by vacuum filtration, centrifugal filtration, pressure filtration, or any other method using known apparatus, but is not limited thereto. The filter used for filtration may be a filter paper, a filter cloth or other type of filter, and may be selected from industrially available filters suitable for the apparatus used without particular limitation.Silane MonomersThe monomers to be used may be selected depending on the compatibility with the solvent and the catalyst, the hydrolyzability and other properties. Examples of tetra-functional silane monomers having the above structure (a) include tetramethoxysilane, tetraethoxysilane, and tetraisocyanatosilane, particularly tetraethoxysilane.Examples of the trifunctional silane monomer having the above structure (b) include methyltrimethoxysilane, methyltriethoxysilane, methyldiethoxymethoxysilane, methylethoxydimethoxysilane, methyltrichlorosilane, methylmethoxydichlorosilane, methylethoxydichlorosilane, methyldimethoxysilane, methylmethoxyethoxychlorosilane, methyldiethoxychlorosilane, methyltriacetoxysilane, methyldiacetoxymethoxysilane, methyldiacetoxyethoxysilane, methylacetoxydimethoxysilane, methylacetoxymethoxyethoxysilane, methylacetoxydiethoxysilane, methyltrihydroxysilane, methylmethoxydihydroxysilane, methylethoxydihydroxysilane, methyldimethoxyhydroxysilane, methylethoxymethoxyhydroxysilane, methyldiethoxyhydroxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltrichlorosilane, ethyltriacetoxysilane, ethyltrihydroxysilane, propyltrimethoxysilane, propyltriethoxysilane, propyltrichlorosilane, Propyltriacetoxysilane, propyltrihydroxysilane, butyltrimethoxysilane, butyltriethoxysilane, butyltrichlorosilane, butyltriacetoxysilane, butyltrihydroxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, hexyltrichlorosilane, hexyltriacetoxysilane, hexyltrihydroxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltrichlorosilane, phenyltriacetoxysilane, and phenyltrihydroxysilane, in particular methyltrimethoxysilane.Examples of the bifunctional silane monomer having the above structure (c) include di-tert-butyldichlorosilane, di-tert-butyldimethoxysilane, di-tert-butyldiethoxysilane, dibutyldichlorosilane, dibutyldimethoxysilane, dibutyldiethoxysilane, dichlorodecylmethylsilane, dimethoxydecylmethylsilane, diethoxydecylmethylsilane, dichlorodimethylsilane, dimethoxydimethylsilane, diethoxydimethylsilane, and diethyldimethoxysilane, particularly dimethyldimethoxysilane.Other Physical Properties of Composite Fine ParticlesThe absolute specific gravity of the composite fine particles disclosed herein may be 1.00 g / cm 3 to 1.60 g / cm 3. When it is in such a range, the external additive is less likely to be embedded in the surfaces of the toner particles when the toner is loaded by the carrier and other elements. This is advantageous from the viewpoint of reducing the contamination of the charge applying members. The absolute specific gravity of the external additive can be controlled by the amount of the fine particles B added. In some embodiments, the absolute specific gravity of the composite fine particles may be 1.35 g / cm 3 to 1.55 g / cm 3.For the composite fine particles disclosed herein, when cross-sections of the fine particles A are observed by electron microscopy using a transmission electron microscope, the average of the Sb / Sa values of 100 fine particles A may be 0.00 to 0.50, where Sa is the area of the cross-section X of an individual fine particle A and Sb is the total area of the fine particles B contained entirely within the cross-section X without being exposed to the outside. In this case, the external additive is less likely to be embedded in the surfaces of the toner particles when the toner is loaded by carriers and other elements. Therefore, such composite fine particles are advantageous in reducing the contamination of the charge applying members. The Sb / Sa value can be controlled by the amount of the fine particles B added as well as the time and temperature of the reaction of the fine particles B with the monomers constituting the fine particles A.In the composite fine particles, the ratio BD / AD of the number average primary particle diameter BD of the fine particles B to the number average primary particle diameter AD of the fine particles A may be in the range of 0.05 to 0.70. When it is in such a range, the composite fine particles have a more effective effect of scraping. The number-average primary particle diameter of the fine particles A can be controlled by controlling the reaction conditions in the hydrolysis and condensation steps as described above. The number-average primary particle diameter of the fine particles B can be controlled by the selection of the fine particles added.The fine particles B of the composite fine particles disclosed herein may be silica or alumina fine particles. Such fine particles have a suitable hardness as the fine particles B and are advantageous in terms of reducing the contamination of the charge applying members and also have stability in durability. In some embodiments, silica fine particles may be selected from the viewpoint of reactivity with the binder component of the fine particles A. The silica fine particles used herein containing silica (SiO 2) as a main component can be prepared using silica compounds such as water glass or alkoxysilane as a raw material or prepared by pulverizing quartz.Examples of silica fine particles include silica particles prepared by a sol-gel method, precipitated silica particles prepared by precipitation, aqueous colloidal silica particles, fumed silica particles prepared in a gas phase process, and fused silica particles. From the viewpoint of reactivity with the binder component and dispersion stability, aqueous colloidal silica particles can be used. Aqueous colloidal silica particles can be obtained commercially or prepared by known methods using a variety of starting materials. For example, aqueous colloidal silica particles can be prepared from silica derived from an alkaline silicate solution having a pH of about 9 to 11, and silicate anions form silica particles having a desired particle size by polymerization in the form of an aqueous dispersion liquid.The composite fine particles disclosed herein can be surface-treated with a water-repellent. The water repellent may be, but is not limited to, an organic silicon compound. Examples of the hydrophobicizing agent include alkyl silazane compounds such as hexamethyldisilazane; alkylalkoxysilane compounds such as diethyldiethoxysilane, trimethylmethoxysilane, methyltrimethoxysilane and butyltrimethoxysilane; fluoroalkylsilane compounds such as trifluoropropyltrimethoxysilane; chlorosilane compounds such as dimethyldichlorosilane and trimethylchlorosilane; siloxane compounds such as octamethylcyclotetrasiloxane; and silicone oil and silicone varnishes.The hydrophobicity of the surface of the composite fine particles can reduce the change in electrostatic adhesion of the toner after the durability test. In some embodiments, the composite fine particles are surface-treated with at least one compound selected from the group consisting of alkyl silazane compounds, alkylalkoxysilane compounds, chlorosilane compounds, siloxane compounds, and silicone oil. Alkyl silazane compounds are particularly advantageous from the above-mentioned points of view.The amount of the composite fine particles disclosed herein may be 0.1 to 20.0 parts by mass with respect to 100 parts of the toner particles from the viewpoint of charge stability, and may be 0.5 to 15.0 parts by mass or 1.0 to 10.0 parts by mass in some embodiments. Such an amount of composite fine particles may be present in a sufficient amount on the surfaces of the toner particles, adjusting the effect of reducing the contamination of the charge applying members.Fine Particles CThe fine particles C are either titanium oxide fine particles or titanic acid compound fine particles, and have a volume resistivity of 2.0×10 9 Ω·cm to 2.0×10 13 Ω·cm, and a number-average primary particle diameter of 10 nm to 100 nm.Such fine particles C can control the charge distribution of the toner to be sharp.The number-average primary particle diameter of the fine particles C may be 20 nm to 60 nm or 20 nm to 50 nm. The number-average primary particle diameter of the particles can be controlled by the concentration, the reaction temperature, and the reaction time of the raw material.The volume resistivity of the fine particles C may be 1.0×10 10 Ω·cm to 5.0×10 12 Ω·cm, or 1.0×10 10 Ω·cm to 3.5×10 11 Ω·cm. By controlling the number-average primary particle diameter and the volume resistivity of the fine particles C in the above ranges, the charge distribution of the toner can be controlled to be sharp, thereby improving dot reproducibility and reducing scattering of the toner.The amount of the fine particles C may be 0.05 to 2.0 parts by mass, for example, 0.2 to 1.7 parts by mass, based on 100 parts by mass of the toner particles.The amount of the composite fine particles (W) added to the amount of the fine particles C (WC) added is 5.0 ≤ W / WC ≤ 20.0, for example 6.0 ≤ W / WC ≤ 10.0. If their proportion is in such a range, the composite fine particles and the fine particles C can effectively contribute to the improvement of dot reproducibility and the reduction of scattering of the toner.When the fine particles C are titanium oxide fine particles, any known titanium oxide fine particles can be used as long as the volume resistivity and the number average primary particle diameter are in the above ranges.The crystals of the titanium oxide fine particles may have either the rutile or anatase form.In some embodiments, the fine particles C are titanic acid compound fine particles. The titanic acid compound fine particles may be made of potassium titanate, barium titanate, strontium titanate, calcium titanate, magnesium titanate, lead titanate, aluminum titanate, lithium titanate, or another titanate. Strontium titanate and calcium titanate are advantageous for achieving the desired charge distribution.The fine particles C may have a CuKα X-ray diffraction spectrum in which the highest peak is at a diffraction angle (2θ) of 32.00 degrees to 32.40 degrees, and the half width of the highest peak may be 0.23 degrees to 0.50 degrees. Such fine particles C improve dot reproducibility.The fine particles C may be surface-treated as needed for hydrophobicization or for controlling triboelectric chargeability or volume resistivity. Examples of such surface treatment agents include unmodified silicone varnish, various modified silicone varnishes, unmodified silicone oil, various modified silicone oils, silane coupling agents, silane compounds having functional groups, and other organic silicon compounds. Some kinds of treating agents may also be used in combination. In some embodiments, the fine particles C are treated with a silane coupling agent. In other words, the fine particles C may be titanic acid compound fine particles surface-treated with a silane coupling agent.Examples of silane coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, n-butyltrimethoxysilane, isobutyltrimethoxysilane, trimethylmethoxysilane, n-hexyltrimethoxysilane, n-octyltrimethoxysilane, n-octyltriethoxysilane, n-decyltrimethoxysilane, hydroxypropyltrimethoxysilane, n-hexadecyltrimethoxysilane, n-octadecyltrimethoxysilane, Trifluoropropyltrimethoxysilane and hydrolysates davo.In some embodiments, n-octyltriethoxysilane, isobutyltrimethoxysilane, or trifluoropropyltrimethoxysilane, especially isobutyltrimethoxysilane, may be selected. The treating agents may be used singly or in combination.The titanic acid compound fine particles may be doped with metal elements other than the metal element of the titanate. Examples of the metallic elements used for doping include, but are not limited to, lanthanum, silicon, aluminum, magnesium, calcium, manganese, rhodium, ruthenium, iridium, tantalum, chromium, antimony, nickel, and niobium. Lanthanum is useful for roundness control.The titanic acid compound fine particles can be produced by any method without limitation. For strontium titanate, for example, the following method can be used. A titanyl sulfate solution is hydrolyzed to prepare an aqueous titanium oxide slurry, and then the pH is adjusted to form a titanium dioxide sol dispersion liquid. Then, strontium nitrate, strontium chloride or the like is added to the dispersion liquid, and after heating to a reaction temperature, an alkaline aqueous solution is added for synthesis. The reaction temperature may be 60° C. to 100° C.In addition of the alkaline aqueous solution for controlling the number average primary particle diameter, the time for this operation may be 60 minutes or less. In addition, ultrasonic vibration may be applied during addition of the alkali aqueous solution to control circularity.The aqueous solution can be rapidly cooled after completion of the reaction by adding the alkali aqueous solution from the viewpoint of controlling the diameter and roundness of the primary particles. For rapid cooling, pure water cooled to 10° C. or less may be brought to a desired temperature, for example. By the rapid cooling, the circularity can be controlled to a high level. Components of toner particlesThe components of the toner particles disclosed herein will now be described in detail.Binder resinThe toner particles contain a binder resin, and any known binder resin may be used in the toner particles. Examples of the binder resin includeStyrene resins, styrene copolymer resin, polyester resin, polyol resin, polyvinyl chloride resin, phenol resin, natural resin-modified phenol resin, natural resin-modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyurethane resin, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral, terpene resin, coumarone-indene resin, and petroleum-based resin. Among these, styrene copolymer resin, polyester resin and blends or hybrid resin of polyester resin and styrene copolymer resin may be more advantageous. In some embodiments, polyester resin is used.Polyester resinThe components of the polyester resin will be described in detail below. The following components may be used singly or in combination depending on the kind and use.Polyester resin contains dibasic carboxylic acid components. Examples include dicarboxylic acids and their derivatives, for example, benzenedicarboxylic acids and their anhydrides or lower alkyl esters such as phthalic acid, terephthalic acid, isophthalic acid and phthalic anhydride; alkyldicarboxylic acids and their anhydrides or lower alkyl esters such as succinic acid, adipic acid, sebacic acid and azelaic acid; alkenylsuccinic acids or alkylsuccinic acids having an average of 1 to 50 carbon atoms and their anhydrides or lower alkyl esters; unsaturated dicarboxylic acids and their anhydrides or lower alkyl esters such as fumaric acid, maleic acid, citraconic acid and itaconic acid.The alkyl group of the lower alkyl esters may be methyl, ethyl, propyl or isopropyl.The dihydric alcohol components of the polyester resin include, for example, ethylene glycol, polyethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-methyl-1,3-propanediol, 2-ethyl-1,3-hexanediol, 1,4-cyclohexanedimethanol (CHDM), hydrogenated bisphenol A, bisphenols represented by the formula (I-1) and their derivatives and diols represented by the formula (I-2): ( In the formula (I-1), R represents an ethylene or propylene group, x and y are each an integer of 0 or more, and the average of x + y is 0 to 10). ( In formula (I-2), R' represents an ethylene or propylene group, x' and y' are each an integer of 0 or more, and the average of x' + y' is 0 to 10).The polyester resin may also contain, in addition to the dicarboxylic acid component and the dihydric alcohol component, trivalent or higher-valent carboxylic acid components and trivalent or higher-valent alcohol components.Examples of trivalent or higher-valent carboxylic acid components include trimellitic acid, trimellitic anhydride, and pyromellitic acid, among others. Examples of trivalent or higher-valent alcohol components include trimethylolpropane, pentaerythritol, and glycerol.The polyester resin may contain, in addition to the above-mentioned components, monovalent carboxylic acid components and monovalent alcohol components. Examples of monovalent carboxylic acid components include palmitic acid, stearic acid, arachidonic acid, behenic acid, cerotic acid, heptacosanoic acid, montanic acid, melissic acid, laccer acid, tetraconthanoic acid and pentaconthanoic acid.Examples of monohydric alcohol components also include behenyl alcohol, ceryl alcohol, melissyl alcohol and tetracontanol.Coloring AgentThe toner can be used as a one-component magnetic toner, a one-component non-magnetic toner or a two-component non-magnetic toner.When the toner is used as the one-component magnetic toner, magnetic iron oxide particles can be used as the colorant. Exemplary materials of the magnetic iron oxide particles contained in the one-component magnetic toner include magnetic iron oxides such as magnetite, maghemite and ferrite, and magnetic iron oxides containing other metal oxides; metals such as Fe, Co and Ni and their alloys with Al, Co, Cu, Pb, Mg, Ni, Sn, Zn, Sb, Be, Bi, Cd, Ca, Mn, Se, Ti, W or V; and mixtures thereof. The amount of magnetic iron oxide particles may be 30 parts by mass to 150 parts by mass with respect to 100 parts by mass of the binder resin.When the toner is used as a one-component non-magnetic toner or a two-component non-magnetic toner, the following colorant may be used.Examples of black pigments include carbon blacks such as furnace black, channel black, acetylene black, thermal black and lamp black, and magnetic powders such as magnetite and ferrite.For yellow colorants, pigments or dyes may be used. Examples of yellow pigments include C.I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 17, 23, 62, 65, 73, 74, 81, 83, 93, 94, 95, 97, 98, 109, 110, 111, 117, 120, 127, 128, 129, 137, 138, 139, 147, 151, 154, 155, 167, 168, 173, 174, 176, 180, 181, 183, and 191; and C.I. Vat Yellow 1, 3, and 20. Examples of yellow dyes include C.I. Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, and 162. These colorants may be used singly or in combination.Pigments or dyes can be used for cyan colorants. Examples of cyan pigments include C.I. Pigment Blue 1, 7, 15, 15:1, 15:2, 15:3, 15:4, 16, 17, 60, 62, and 66, C.I. Vat Blue 6, and C.I. Acid Blue 45. Examples of cyan dyes include C.I. Solvent Blue 25, 36, 60, 70, 93, and 95.For magenta colorants, pigments or dyes may be used. Examples of magenta pigments include C.I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48, 48:2, 48:3, 48:4, 49, 50, 51, 52, 53, 54, 55, 57, 57:1, 58, 60, 63, 64, 68, 81, 81:1, 83, 87, 88, 89, 90, 112, 114, 122, 123, 144, 146, 150, 163, 166, 169, 177, 184, 185, 202, 206, 207, 209, 220, 221, 238, and 254, C.I. Pigment Violet 19, and C.I. Vat Red 1, 2, 10, 13, 15, 23, 29, and 35.Examples of magenta dyes include oil-soluble dyes such as C.I. Solvent Reds 1, 3, 8, 23, 24, 25, 27, 30, 49, 52, 58, 63, 81, 82, 83, 84, 100, 109, 111, 121, and 122, C.I. Disperse Red 9, C.I. Solvent Violet 8, 13, 14, 21, and 27, and C.I. Disperse Violet 1; and basic dyes such as C.I. Basic Red 1, 2, 9, 12, 13, 14, 15, 17, 18, 22, 23, 24, 27, 29, 32, 34, 35, 36, 37, 38, 39, and 40, C.I. Basic Violet 1, 3, 7, 10, 14, 15, 21, 25, 26, 27, and 28.The amount of the colorant may be 1 to 20 parts by mass with respect to 100 parts by mass of the binder resin.Release AgentA releasing agent (wax) may be used to impart releasability to the toner.Examples of waxes include aliphatic hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, olefin copolymers, microcrystalline waxes, paraffin waxes and Fischer-Tropsch waxes; oxides of aliphatic hydrocarbon waxes such as polyethylene oxide waxes; waxes mainly containing fatty acid esters such as carnauba wax, behenyl behenate wax and montanate ester wax; and waxes with partially or completely deoxidized fatty acid esters such as deoxidized carnauba wax.Further examples include saturated linear fatty acids such as palmitic acid, stearic acid and montanic acid; unsaturated fatty acids such as brassidic acid, eleostearic acid and parinaric acid; saturated alcohols such as stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnauba alcohol, ceryl alcohol and melissyl alcohol; polyhydric alcohols such as sorbitol; fatty acid amides such as linolamide, oleamide and lauramide; saturated fatty acid bisamides such as methylene bis(stearamide), ethylene bis(capramide), ethylene bis(lauramide) and hexamethylene bis(lauramide); Unsaturated fatty acid amides such as ethylenebis(oleamide), hexamethylenebis(oleamide), N,N'-dioleyl adipamide and N,N'-dioleyl sebacamide; aromatic bisamides such as m-xylenebis(stearamide), N,N'-distearyl isophthalamide; fatty acid metal salts (generally called metal soap) such as calcium stearate, calcium laurate, zinc stearate and magnesium stearate; aliphatic hydrocarbon waxes grafted with copolymerizable vinyl-based monomers such as styrene or acrylic acid; partial esters prepared from fatty acids and polyhydric alcohols such as behenic acid monoglyceride; and hydroxy ester compounds prepared by hydrogenating vegetable fats and oils.In one embodiment, aliphatic hydrocarbon waxes may be used. Such waxes include, for example, low molecular weight hydrocarbons obtained by radical polymerization of alkylene under high pressure or by polymerization using a Ziegler catalyst or a metallocene catalyst under low pressure; Fischer-Tropsch wax synthesized from coal or natural gas; paraffin wax, olefin polymers produced by thermal decomposition of high molecular weight olefin polymers; synthetic hydrocarbon waxes obtained from the distillation residue of hydrocarbons obtained from carbon monoxide- and hydrogen-containing synthesis gas by the Agee process; and synthetic hydrocarbon waxes produced by hydrogenation thereof.In addition, hydrocarbon waxes fractionated by the press sweating method, the solvent method, vacuum distillation or fractional crystallization may also be used. Especially, n-paraffin waxes and Fischer-Tropsch waxes, which are paraffins containing predominantly linear components, are advantageous in terms of molecular weight distribution.The above waxes may be used singly or in combination. The amount of the wax to be added may be 1 to 20 parts by mass with respect to 100 parts by mass of the binder resin.Charge Control AgentThe toner may contain a charge control agent. Known charge control agents may be used. Examples include azo iron compounds, azo chromium compounds, azo manganese compounds, azo cobalt compounds, azo zirconium compounds, chromium compounds of carboxylic acid derivatives, zinc compounds of carboxylic acid derivatives, aluminum compounds of carboxylic acid derivatives, and zirconium compounds of carboxylic acid derivatives. The carboxylic acid derivative may be an aromatic hydroxycarboxylic acid. Charge control resins may be used. A single charge control agent or a combination of two or more charge control agents may be used as desired. The amount of the charge control agent may be 0.1 parts by mass to 10 parts by mass with respect to 100 parts by mass of the binder resin.Inorganic fine powderThe toner disclosed herein may contain a plurality of inorganic fine powders in addition to the external additive of the toner as needed. The inorganic fine powder may be internally added to the toner particles or mixed as an external additive with the toner base materials. When used as an external additive, inorganic fine powder such as silica may be used. The inorganic fine powder may be hydrophobicized with a hydrophobicizing agent such as a silicon compound, silicone oil or a mixture thereof.When an external additive is used for improving flowability, inorganic fine powder having a specific surface area of 50 m 2 / g to 400 m 2 / g can be used. For improving the flowability and stabilizing the durability, inorganic fine particles having a specific surface area in the above range may be used in combination.The amount of inorganic fine powder may be 0.1 to 10.0 parts by mass with respect to 100 parts by mass of toner particles. When the amount is in this range, the durability is usually stable.Production Method of Toner ParticlesThe toner particles can be produced by any known method without particular limitation. For example, pulverization, emulsion aggregation, suspension polymerization or solution suspension may be used.PulverizationIn a pulverization process, the toner particles are produced, for example, as described below.A binder resin, a colorant, and optional additives are sufficiently mixed with a mixer such as a Henschel mixer or a ball mill. The resulting mixture is melt-kneaded in a heat kneader such as a twin-screw kneader, a heating kneader, a kneader or an extruder. At this time, wax, magnetic iron oxide particles and a metal-containing compound may be added.The melt-kneaded material is cooled to solidify, and then pulverized and classified to obtain toner particles. At this time, the embedding rate of the silica fine particles in the surfaces of the toner particles can be controlled by adjusting the discharge temperature during pulverization. The toner particles and the external additive such as silica fine particles are mixed with a Henschel mixer, so that the toner is produced.Examples of the mixer include Henschel mixer (manufactured by Nippon Coke & Engineering); Super Mixer (manufactured by Kawata); Ribocone (manufactured by Okawara MFG.); Nauta Mixer, Turbulizer, and Cyclomix (all manufactured by Hosokawa Micron); Spiral Pin Mixer (manufactured by Pacific Machinery & Engineering); and Loedige Mixer (manufactured by Matsubo).Examples of the screw kneader include KRC kneader (manufactured by Kurimoto); Buss Co kneader (manufactured by Buss); TEM extruder (manufactured by Shibura Machine); TEX twin screw kneader (manufactured by Japan Steel Works); PCM kneader (manufactured by Ikegai); three roll mill, mixing roll mill and kneader (all manufactured by Inoue MFG); Kneadex (manufactured by Nippon Coke & Engineering); MS pressure kneader and kneader rudder (both manufactured by Moriyama); and Banbury mixer (manufactured by Kobe Steel).Examples of pulverizers include Counter Jet Mill, Micron Jet and Inomizer (all manufactured by Hosokawa Micron); IDS Mill and PJM Jet Mill (both manufactured by Nippon Pneumatic); Cross Jet Mill (manufactured by Kurimoto); ULMAX (manufactured by Nisso Engineering); SK Jet-O-Mill (manufactured by Seishin Enterprise); KRYPTRON (manufactured by Kawasaki Heavy Industries); Turbo Mill (manufactured by Freund Turbo); and Super Rotor (manufactured by Nisshin Engineering).After pulverization, the toner particles may be surface-treated to control the embedding rate of the silica fine particles in the surfaces of the toner particles. For this, the hybridization system (manufactured by Nara Machinery), Nobilta (manufactured by Hosokawa Micron), Mechanofusion System (manufactured by Hosokawa Micron), Facility (manufactured by Hosokawa Micron), Inomizer (manufactured by Hosokawa Micron), Theta Composer (manufactured by Tokuju Corporation), MECHANOMILL (manufactured by Okada Seiko) or Meteorainbow MR (manufactured by Nippon Pneumatic) are used.Examples of classifiers include Classiciel, Micron Classifier, and Speedic Classifier (all manufactured by Seishin Enterprise); Turbo Classifier (manufactured by Nisshin Engineering); Micron Separator, Turboplex (ATP), and TSP Separator (all manufactured by Hosokawa Micron); Elbow-Jet (manufactured by Nittetsu Mining); Dispersion Separator (manufactured by Nippon Pneumatic); and YM Micro Cut (manufactured by Uras Techno).Examples of screens used for screening coarse particles include ultrasound (available from Kouei Industry), Resonaseve, and Gyaro screener (manufactured by Tokuju Corporation), Vibrasonic System (manufactured by Dalton), Soniclean (manufactured by Sintokogio), Turbo Cleaner (manufactured by Freund's turbo), Micro Sifter (manufactured by Makino Sangyo), and round vibrating screen separators.Emulsion Aggregation MethodIn an emulsion aggregation process, the toner particles are prepared, for example, as described below.preparing resin fine particle dispersion liquid (dispersion liquid preparation step):For example, polyester resin, styrene resin or acrylic resin as a binder resin component is dissolved in an organic solvent to prepare a homogeneous solution. Then, basic compounds and surfactants are added as needed. To the resulting solution, an aqueous medium is gradually added while applying a shearing force with a homogenizer or the like to form fine particles of the binder resin. Finally, the organic solvent is removed to obtain a resin fine particle dispersion liquid in which the resin fine particles are dispersed.In preparing the resin fine particle dispersion liquid, the amount of the resin component dissolved in the organic solvent may be 10 to 50 parts by mass, for example, 30 to 50 parts by mass, based on 100 parts by mass of the organic solvent.Any solvent that can dissolve the resin component can be used, but in some embodiments, solvents such as toluene, xylene, and ethyl acetate that are very soluble for olefin resin can be used.The surfactant is not limited. Examples of surfactants include anionic surfactants such as sulfuric ester salt-based surfactants, sulfonates-based surfactants, carboxylates-based surfactants, phosphoric ester-based surfactants and soaps-based surfactants; cationic surfactants such as amine salt surfactants and quaternary ammonium salt surfactants; and nonionic surfactants such as polyethylene glycol-based surfactants, alkylphenol ethylene oxide adduct-based surfactants and polyhydric alcohol-based surfactants.Examples of the basic compound include inorganic bases such as sodium hydroxide and potassium hydroxide, and organic bases such as triethylamine, trimethylamine, dimethylaminoethanol and diethylaminoethanol. Such basic compounds may be used singly or in combination.- Aggregation step:In the aggregation step, for example, the resin fine particle dispersion liquid prepared above is mixed with a dispersion liquid of colorant fine particles, a dispersion liquid of wax fine particles, and a silicone oil emulsion as needed to prepare a mixture, and the fine particles in the mixture are aggregated into aggregated particles.For example, to form aggregated particles, a flocculant is added to the above mixture and mixed therewith, followed by temperature elevation or mechanical energy addition as needed.The dispersion of the colorant fine particles is prepared by dispersing the colorant described above. The colorant fine particles can be dispersed by any known method, so that, for example, a rotary shear homogenizer, a medium dispersing apparatus such as a ball mill, a sand mill or an attritor, a high pressure countercollision disperser, or another dispersant can be used. In addition, a surfactant or a polymeric dispersant may be added to impart stability to the dispersion.The wax fine particle dispersion liquid and the silicone oil emulsion are prepared by dispersing the respective materials in aqueous media. Each material can be dispersed by any known method, for example, a rotary shear homogenizer, a medium dispersing apparatus such as a ball mill, a sand mill or attritor, a high pressure countercollision disperser, or other dispersing apparatus. In addition, a surfactant or a polymeric dispersant may be added to impart stability to the dispersion.Examples of flocculant include monovalent metal salts such as sodium and potassium salts; divalent metal salts such as calcium and magnesium salts; trivalent metal salts such as iron and aluminum salts; and polyvalent metal salts such as polyaluminum chloride. From the viewpoint of controlling the particle size in the aggregation step, divalent metal salts such as calcium chloride and magnesium sulfate may be used.The addition and mixing of the flocculant may be carried out at a temperature of room temperature to 75 °C. When the mixing is carried out at a temperature in this range, aggregation proceeds stably. The mixing step may be performed with a known mixing machine such as a homogenizer or a mixer.- Melting step:In the melting step, the aggregated particles are heated, for example, to a temperature corresponding to or higher than the melting point of the olefin resin to melt the particles, so that particles having smooth surfaces are produced.Before the melting step, a chelating agent, a pH adjuster, a surfactant or the like may be added as needed to prevent the resin particles from melting together.Examples of chelating agents include ethylenediaminetetraacetic acid (EDTA) and its alkali metal salts such as sodium salts, sodium gluconate, sodium tartrate, potassium citrate and sodium citrate, nitrilotriacetate (NTA) salts and water soluble polymers (polyelectrolytes) with both functionalities COOH and OH.High temperature heating shortens the time of melting, while low temperature heating lengthens the time of melting. In other words, the time of heating and melting depends on the heating temperature and is not generally fixed, but is usually about 10 minutes to 10 hours.- Cooling step:The aqueous medium containing the resin particles obtained in the melting step is cooled. The cooling rate may be, in particular, about 0.1° C. / min to 50° C. / min, but is not limited thereto.- Washing step:The resin particles thus obtained are repeatedly washed and filtered to remove impurities from the resin particles.More specifically, the resin particles can be washed with an aqueous solution containing a chelating agent such as ethylenediaminetetraacetic acid (EDTA) or its sodium salt and further with pure water.The metal salts, surfactants and the like in the resin particles can be removed by repeated washing and filtration with pure water. The filtration may be performed 3 to 20 times, for example, 3 to 10 times, from the viewpoint of production efficiency.drying and classification step:The washed resin particles are dried and then classified accordingly to obtain toner particles.Solution suspensionIn a solution suspension process, the toner particles are prepared, for example, as described below.In the solution suspension method, a resin composition prepared by dissolving a binder resin component such as polyester resin or styrene-acrylic resin in an organic solvent is dispersed in an aqueous medium to form particles of the resin composition, and then the organic solvent in the particles of the resin composition is removed to obtain toner particles.Such a solution suspension method can be used for any resin component which dissolves in organic solvents, and moreover enables easy shape control by the conditions in the removal of the solvent.An exemplary method for producing the toner using a solution suspension will be described below, but is not limited to the following method.resin component dissolving step:In this step, the binder resin and optionally other components such as a colorant, wax and silicone oil are dissolved or dispersed in an organic solvent to prepare a resin composition.The organic solvent may be any organic solvent capable of dissolving the resin component. Specific examples include toluene, xylene, chloroform, methylene chloride and ethyl acetate. In some embodiments, toluene or ethyl acetate may be used because these solvents may promote crystallization of crystalline resin and are easily removed.The amount of the organic solvent used is not limited as long as the resin composition can be dispersed in a poor medium such as water to a viscosity that enables the formation of particles. More specifically, the mass ratio of the resin component and other optional components including the colorant, the wax and the silicone oil to the organic solvent may be 10 / 90 to 50 / 50 from the viewpoint of easy particle formation and efficiency of toner particle production.The colorant, wax and silicone oil need not necessarily be dissolved in water and may be dispersed. When used in dispersion, the colorant, wax and silicone oil may be dispersed with a dispersing agent such as a bead mill.- Particle forming step:In the particle formation, the resulting resin composition is dispersed in an aqueous medium with a dispersant to prepare the resin composition particles so that the toner particles may have a certain particle size.The aqueous medium is generally water.The aqueous medium may contain 1 to 30 mass % of monovalent metal salt. The monovalent metal salt in the aqueous medium suppresses the diffusion of the organic solvent in the resin composition into the aqueous medium to increase the crystallinity of the resultant toner particles.As a result, the toner is likely to have a good anti-blocking property and a good particle size distribution.Examples of the monovalent metal salt include sodium chloride, potassium chloride, lithium chloride, and potassium bromide, and in some embodiments, sodium chloride or potassium chloride is used.The mixing ratio (mass ratio) between the aqueous medium and the resin composition, aqueous medium / resin composition, may be 90 / 10 to 50 / 50.The dispersing agent used is not limited, and as the organic dispersing agent, a cationic, anionic or nonionic surfactant, particularly an anionic, may be used.Specific examples include sodium alkylbenzenesulfonate, sodium α-olefinsulfonate, sodium alkylsulfonate, and sodium alkyldiphenyl ether disulfonate. Inorganic dispersants may also be used, and examples include tricalcium phosphate, hydroxyapatite, calcium carbonate fine particles, titanium dioxide fine particles and silica fine particles.In some embodiments, tricalcium phosphate, which is an inorganic dispersant, is used. This is because the negative effect of tricalcium phosphate on the particle formation and its stability and, moreover, on the properties of the resulting toner is very low.The amount of dispersant added will depend on the particle size of the particles to be formed. The larger the amount of the dispersant added, the smaller the particles. Accordingly, in some embodiments, the amount of the dispersant added may be 0.1 to 15.0 mass %, based on the mass of the resin composition, but varies depending on the desired particle size.The preparation of the resin composition particles in the aqueous medium can be carried out by high-speed shearing. The apparatus for high-speed shearing may be a high-speed disperser or an ultrasonic disperser.Solvent Removal Step:In the solvent removal, the organic solvent contained in the resulting resin composition particles is removed to obtain the toner particles. The removal of the organic solvent can be carried out with stirring.washing, drying and classifying steps:After the solvent removal step, the toner particles may be washed with water or the like several times, followed by filtration and drying. If a dispersant soluble under acidic conditions, for example tricalcium phosphate, is used, the toner particles are preferably washed with hydrochloric acid and then with water. The washing removes the dispersant used to form the particles. After washing, the particles are filtered, dried and classified to obtain toner particles.Suspension PolymerizationIn a suspension polymerization process, the toner particles are prepared, for example, as described below.Polymerizable monomers constituting the binder resin, a colorant, a wax component and a polymerization initiator are uniformly dissolved or dispersed with a dispersing apparatus such as a homogenizer, a ball mill or an ultrasonic dispersing apparatus to prepare a polymerizable monomer composition. The polymerizable monomer composition is dispersed in an aqueous medium to form particles of the polymerizable monomer composition. Subsequently, the polymerizable monomers in the particles of the polymerizable monomer composition are polymerized, thereby forming toner particles.The polymerizable monomer composition can be prepared by mixing a dispersion liquid in which the colorant is dispersed in a first polymerizable monomer (or a part of a polymerizable monomer) with at least one second polymerizable monomer (or the remainder of the polymerizable monomer). By sufficiently dispersing the colorant in the first polymerizable monomer and then mixing the dispersion liquid with the second polymerizable monomer together with other toner components, the colorant can be in a well-dispersed state in the polymerized particles.The resulting toner particles can be filtered, washed, dried and sized as needed.Addition of External Additive to Toner ParticlesThe toner particles obtained by any of the above-described methods and the external additive are mixed with a mixer such as a Henschel mixer to obtain the toner.The toner may have a weight average particle size (D4) of 4.0 μm to 15.0 μm. In some embodiments, the weight average particle size of the toner is 4.0 μm to 9.0 μm or 6.0 μm to 8.0 μm.The weight-average particle size (D4) of the toner can be adjusted by classifying the toner particles, for example.DeveloperAlthough the toner disclosed herein can be used as a one-component developer, it can be mixed with a magnetic carrier to improve dot reproducibility and thus used as a two-component developer, which is advantageous in view of consistently providing images over a long period of time. The two-component developer contains a toner and a magnetic carrier, and the toner is preferably the toner disclosed herein.When the toner is mixed with a magnetic carrier to be used as a two-component developer, the content of toner in the two-component developer may be 2 to 15 mass %, for example, 4 to 13 mass %.Magnetic CarrierThe magnetic carrier may be an ordinary magnetic carrier such as ferrite or magnetite, or a resin-coated carrier. Alternatively, magnetic material dispersed resin particles prepared by dispersing magnetic material in the resin component or porous magnetic core particles containing resin in the pores may be used.Examples of the magnetic material of the magnetic material dispersed resin particles include magnetite powder, maghemite powder, and magnetic iron oxide powder which is magnetite or maghemite powder and contains at least one selected from the group consisting of oxides and hydroxides of silicon and oxides and hydroxides of aluminum; magnetoplumbite ferrite powder containing barium, strontium, or barium strontium; spinel ferrite containing at least one selected from the group consisting of manganese, nickel, zinc, lithium, and magnesium; and other magnetic iron compound powders.In addition to these magnetic materials, other powder materials may also be used in combination with magnetic iron compound powder, and examples include non-magnetic iron oxide powder such as hematite powder, iron hydroxide-containing non-magnetic powder such as goethite, non-magnetic inorganic compound powder such as titanium oxide powder, silica powder, talc powder, alumina powder, barium sulfate powder, barium carbonate powder, cadmium yellow powder, calcium carbonate powder and hydrozincite powder.The material of the porous magnetic core particles may be magnetite or ferrite. Exemplary ferrite is represented by the following formula: (M1 2 O) x( M2 O) y( Fe 2 O 3)zIn the formula, M1represents a monovalent metal and M2represents a divalent metal. Also, 0 ≤ (x, y) ≤ 0.8 and 0.2 < z < 1.0 when x + y + z = 1.0.At least one selected from the group consisting of Li, Fe, Mn, Mg, Sr, Cu, Zn, and Ca may be used as M1or M2. In addition, Ni, Co, Ba, Y, V, Bi, In, Ta, Zr, B, Mo, Na, Sn, Ti, Cr, Al, Si, and rare earth elements may be used.In some embodiments, the magnetic carrier is a resin coated carrier that includes magnetic carrier core particles and a resin coating layer over the surfaces of the magnetic carrier core particles. The resin coating layer coats, for example, the surface of the magnetic carrier core particle. The magnetic carrier core particles may be porous magnetic core particles containing resin in the pores.The resin filling the pores of the porous magnetic particles may be either a thermoplastic resin or a thermosetting resin.Examples of thermoplastic resins include novolak resin, saturated alkyl polyester resin, polyarylate, polyamide resin and acrylic resin.Examples of thermosetting resins include phenol-based resins, epoxy resins, unsaturated polyester resins, and silicone resins.The coating of the magnetic carrier core particles with resin can be performed by application techniques such as, but not limited to, dipping, spraying, brush coating, and fluidized bed coating. In some embodiments, dipping may be used.The amount of the resin that coats the surfaces of the magnetic carrier core particles (the amount of the resin coating layers) may be 0.1 to 5.0 parts by mass with respect to 100 parts by mass of the magnetic carrier core particles from the viewpoint of controlling the ability to apply charge to the toner.Examples of the resin used for the resin coating layer include acrylic resins such as acrylic ester copolymers and methacrylic ester copolymers; styrene-acrylic resins such as styrene-acrylic ester copolymers and styrene-methacrylic ester copolymers; and polytetrafluoroethylene, fluorine-containing resins such as polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, monochlorotrifluoroethylene polymer and polyvinylidene fluoride; and silicone resin, polyester resin, polyamide resin, polyvinyl butyral, amino acrylate resin, ionomer resin and polyphenylene sulfide resin.These resins may be used singly or in combination. In some embodiments, acrylic resins are used.From the viewpoint of charge stability, copolymers containing (meth)acrylic esters having alicyclic hydrocarbon groups may be particularly selected. Advantageously, the resin of the resin coating layer contains monomer units of (meth)acrylic acid esters having alicyclic hydrocarbon groups. In other words, the resin of the resin coating layer contains a polymer of monomers containing (meth)acrylic esters having at least one alicyclic hydrocarbon group.Preferable examples of (meth)acrylic acid esters containing an alicyclic hydrocarbon group include cyclobutyl acrylate, cyclopentyl acrylate, cyclohexyl acrylate, cycloheptyl acrylate, dicyclopentenyl acrylate, dicyclopentanyl acrylate, cyclobutyl methacrylate, cyclopentyl methacrylate, cyclohexyl methacrylate, cycloheptyl methacrylate, dicyclopentenyl methacrylate, and dicyclopentanyl methacrylate.The alicyclic hydrocarbon groups may have 3 to 10 or 4 to 8 carbon atoms. Such monomers may be used singly or in combination.The proportion of the monomer units formed of (meth)acrylic esters having alicyclic hydrocarbon groups in the copolymer used for the resin coating layer may be 5.0 to 80.0 mass %, for example, 50.0 to 80.0 mass %, or 70.0 to 80.0 mass %. The monomer units in such a proportion range provide good chargeability in high-temperature and high-humidity environments.Moreover, the resin in the resin coating layer may contain macromonomers as copolymerization components to improve adhesion between the magnetic carrier core particles and the resin coating layers and to reduce local separation of the resin coating layers in view of charge stability. Formula (B) represents an example of macromonomers. In other words, the resin of the resin coating layer may contain monomer units formed by macromonomers represented by the formula (B). In formula (B), A represents a polymer of at least one compound selected from the group consisting of methyl acrylate, methyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, styrene, acrylonitrile, and methacrylonitrile. R 3 represents H or CH 3. In some embodiments, A is a polymer of methyl methacrylate.Measurements of Physical PropertiesThe methods for measuring the physical properties will now be described.Separation of Fine Particles and Toner Particles from TonerFor measuring the physical properties, the fine particles may be separated from the toner by the following method.A concentrated sucrose solution is prepared by dissolving 200 g of sucrose (manufactured by Kishida Chemical) in 100 mL of ion-exchanged water heated in hot water. To prepare a dispersion liquid, 31 g of the concentrated sucrose solution and 6 ml of contaminon N (10 mass % aqueous solution of a neutral detergent having a pH of 7 for cleaning precision measurement instruments, which contains a nonionic surfactant, an anionic surfactant and an organic builder, manufactured by Wako Pure Chemical Corporation), are placed in a centrifuge tube. Then, 1 g of the toner is added to the dispersion liquid, and then the toner aggregates are dispersed with a spatula or the like.The centrifuge tube is shaken for 20 minutes with a shaker, 350 times per minute. After shaking, the liquid is placed in a glass tube (50 mL) for a swing rotor and centrifuged at 3500 U / min for 30 minutes. After centrifugation, the toner in the glass tube is in the upper layer, and the fine particles are in the aqueous solution of the lower layer. The aqueous solution of the lower layer is collected and centrifuged to separate sucrose and fine particles, and the fine particles are collected. If necessary, centrifugation is repeated. After sufficient separation, the dispersion liquid is dried and the fine particles are collected.When a plurality of external additives are added, the external additive disclosed herein may be separated by centrifugation or the like.Measurement of Embedding Rate of Fine Particles BThe composite fine particles are sufficiently dispersed in a visible light curing resin (Aronix LCR Series D-800 (trade name), manufactured by Toagosei), and the mixture is cured by irradiation with short wave light. The resulting cured product is cut out with an ultramicrotome with diamond knife to prepare a 250 nm thick sample. Then, the cut sample, i.e., the cross section of the composite particles, is observed with a transmission electron microscope (JEM-2800 of JEOL), TEM-EDX at 40000 to 5000 times magnification. The diameter of the fine particles B and the depth of embedding of fine particles B in fine particles A are measured from the sectional image. For a composite fine particle, five fine particles B are randomly selected, and the embedding rate of the fine particles B is calculated from the following equation. The number of analyzed particles is set to 20 composite fine particles, and the embedding rates of the fine particles B are averaged.Calculation of Sb / Sa of Composite Fine ParticlesThe cross sections of the composite fine particles are observed in the same manner as described above, and the Sb / Sa of the composite fine particles is calculated by image analysis. The software program for image analysis is, for example, ImageJ. The area Sa of the cross section X of a fine particle A is calculated from the image obtained by the observation, and in the cross section X, the total area Sb of the fine particles B completely contained in the cross section X without being exposed to the outside is calculated. The number of analyzed particles is set to 100 composite fine particles, and their Sb / Sa values are averaged.Calculation of BD / AD of Composite Fine ParticlesThe cross sections of the composite fine particles are viewed in the same manner as above, and BD / AD of the composite fine particles is calculated.The particle size AD of the fine particles A and the particle size BD of the fine particles B are calculated from the image obtained by the observation. The number of analyzed particles is set to 20 composite fine particles, and their BD / AD values are averaged.Determination of Constituent Contents of Composite Fine Particles by Solid-State 29Si NMRIn the solid state 29 Si-NMR, peaks are detected in various displacement ranges depending on the structure of the functional group of the constituent compound bonded to Si in the composite particles. The structure bound to Si at each peak position is identified from reference samples. The proportions of the constituents are also calculated from the peak areas. The ratios of the peak areas of the M unit structure, the D unit structure (c), the T unit structure (b) and the Q unit structure (a) to the total peak area are calculated.Specific measurement conditions of solid state 29 Si-NMR are as follows:Apparatus: JNM-ECX 5002 (JEOL RESONANCE)Temperature: room temperatureMeasurement method: DDMAS 29 Si 45°Sample tubes: Zirconia, 3.2 mm diameterSample: Powder in the sample tubeRotational speed of the sample: 10 kHzRelaxation retardation: 180 secScan: Scan: 2000After the measurement, the silane components in the sample, which differ in substituent and linking group, are separated into the below-shown M unit structure, D unit structure (c), T unit structure (b) and Q unit structure (a) by curve fitting, and their peak areas are calculated.Curve fitting is performed with JEOL Excalibur Windows (registered trademark) version 4.2 (EX series) software for JNM-EX 400 as follows: clicking on "1D Pro" in the menu icon to load the measurement data. Then select "Curve fitting function" from the menu bar "Command" for curve fitting. performing the curve fitting for each component so that the difference between the composite peak resulting from the combination of the peaks obtained by the curve fitting and the peak of the measurement result (difference of the composite peaks) is the smallest.M unit structure: (Ra)(Rb)(Rc)SiO 1 / 2D unit structure: (Rd)(Re)Si(O 1 / 2)2( c)T Unit Structure: RfSi(O 1 / 2)3( b)Q unit structure: Si(O 1 / 2)4( a)Ra, Rb, Rc, Rd, Re, Rfin the formulas are organic groups having 1 to 6 carbon atoms (e.g., alkyl and alkoxy) and halogen and hydroxyl groups bonded to silicon. The proportions of (a), (b) and (c) in the external additive are calculated for the peak areas of the structure represented by formula (a), the structure represented by formula (b) and the structure represented by formula (c) obtained by the measurement. If the structures are to be examined more accurately, identification can be made by combining the results of 13 C-NMR and 1 H-NMR with the results of 29 Si-NMR.Measurement of Absolute Specific Gravity of Composite Fine ParticlesThe absolute specific gravity of the composite fine particles is measured, for example, with an automatic dry density meter autopycnometer (manufactured by Quantachrome Instruments). The measurement conditions are as follows:Cell: SM cell (10 mL)Amount of sample: 0.05 gThis method determines the absolute specific weights of solid and liquid materials on the basis of gas pycnometry.Gas pycnometry, like liquid pycnometry, is based on the Archimedes principle and is more precise due to the use of gas (argon gas) as replacement medium for very small pores.Measurement of Number Average Particle Diameter of External AdditiveThe number and particle sizes (largest size) of the composite fine particles and fine particles C on the surfaces of the toner particles can be measured by observing the toner particles under a scanning electron microscope (SEM). At this time, the energy dispersive X-ray analysis (EDS) associated with the SEM may be used to confirm that the measurement object is the composite fine particles or the particles C. Each of the number average particle diameters is the average of the measurements of 100 toner particles.Measurement of Volume Resistivity of Fine Particles CFor the measurement, the electrometer / high resistance system model 6517 manufactured by Keithley Instruments can be used. Electrodes having a diameter of 25 mm are connected. The particles are aggregated to a thickness of about 0.5 mm between the electrodes, and the distance between the electrodes is measured with an applied load of about 2.0 N. The resistance of the aggregated particles to which a voltage of 1000 V is applied for 1 minute is measured, and the volume resistivity is calculated from the following equation:Volume resistivity (Ω·cm)=R×LR: Resistance (Ω)L: Distance (cm) between electrodesMeasurement of the weight-average particle size (D4) of the tonerThe weight average particle size (D4) of the toner is measured by the pore electric resistance method using a tube having an opening of 100 μm using a Multisizer 3 Coulter Counter (registered trademark) exact particle size distribution analyzer manufactured by Beckman Coulter and a dedicated software program Multisizer 3 version 3.51 supplied by Beckman Coulter together with the analyzer to set the measurement conditions and analyze the measurement data. For measurement and data analysis, the effective number of measurement channels is set to 25000.The electrolyte solution used for the measurement can be prepared by dissolving highest quality sodium chloride in ion-exchanged water to about 1 mass %, and for example, ISOTON II (manufactured by Beckman Coulter, Inc.) can be used.Prior to measurement and analysis, the above-mentioned dedicated software is set up as described below.On the screen "Change Standard Measurement (SOM)" (translation) of the software, the total number in the control mode is set to 50000 particles, the number of measurements to 1 and Kd to the value obtained with "10.0 μm Standard Particles" (manufactured by Beckman Coulter, Inc.). By pressing the threshold / noise level measurement key, the threshold and noise level are automatically adjusted. The current is set to 1600 μA, the gain to 2 and the electrolyte solution to ISOTON II. A check is set in the indication "Flushing of the diaphragm tube after measurement" (transmission ratio).On the screen "pulse-to-particle size conversion adjustment" (translation) of the intended software, the bin distance is adjusted to logarithmic particle size, the particle size bin to 256 particle size bins, and the particle size range to a range from 2 μm to 60 μm.Specifically, the measurement is performed according to the following method:(1) About 200 mL of the electrolyte solution is placed in a Multisizer 3-specific 250 mL round bottom glass beaker and stirred counterclockwise with a stirring bar at 24 revolutions per second, placing the beaker on a sample stand. The dirt and air bubbles in the aperture tube are removed by the function "aperture flush" of the intended software.(2) About 30 mL of the electrolyte solution is placed in a 100 mL flat-bottom beaker and about 0.3 mL of a dispersant prepared by diluting CONTAMINON N to three times mass with ion-exchanged water is added. CONTAMINON N is a 10 mass % aqueous solution of a pH-7 neutral detergent for precision measurement equipment, which is manufactured by FUJIFILM Wako Pure Chemical Corporation and contains a nonionic surfactant, an anionic surfactant and an organic builder.(3) About 2 mL of contaminon N is added to a certain amount of ion-exchanged water in a water tank of a Tetora 150 ultrasonic dispersion system (manufactured by Nikkaki Bios) having an electric power of 120 W and including two oscillators having an oscillation frequency of 50 kHz and a phase shift of 180°.(4) The beaker of the above (2) is inserted into a beaker mounting hole of the ultrasonic dispersing system, and the ultrasonic dispersing system is started. Then, the height of the beaker is adjusted so that the resonance can be greatest at the level of the electrolyte solution in the beaker.(5) In a state where ultrasonic waves are applied to the electrolytic solution in the beaker of (4), about 10 mg of toner is gradually added to the electrolytic solution and dispersed. Such ultrasonic dispersion is continued for 60 seconds. For ultrasonic dispersion, the water temperature in the water tank is controlled in the range of 10° C. to 40° C. as needed.(6) The electrolytic solution of (5) in which the toner is dispersed is dropped by a pipette into the round bottom beaker of (1) placed on the sample stand to adjust the measurement concentration to about 5%. Then, the measurement is performed until the number of the measured particles reaches 50000.(7) The measurement data is analyzed with the dedicated software and the weight average particle size (D4) is calculated. Here, "average size" on the screen "analysis / volume statistics value (arithmetic mean)" (translation) in a state where graph / volume % is set in the software program represents the weight-average particle size (D 4).EXAMPLESThe basic elements and features of the present disclosure have been described above. The present disclosure will be described in more detail with reference to the following examples. However, the present disclosure is not limited to the examples. In the following description, "part(s)" and "%" are on a mass basis unless otherwise specified.Preparation of Binder Resin 1Bisphenol A Ethylene oxide (2.2 mole adduct): 50.0 mole partsBisphenol A propylene oxide (2.2 mol adduct): 50.0 mol partsTerephthalic acid: 90.0 molar partsTrimellitic anhydride: 10.0 parts by moleThe above monomers constituting the polyester unit in 100 parts by mass were mixed with 500 ppm of titanium tetrabutoxide in a 5-liter autoclave.The autoclave was then equipped with a reflux condenser, a separator, an N 2 gas inlet pipe, a thermometer, and a stirrer, and a condensation polymerization reaction was carried out at 230° C. while introducing N 2 gas into the autoclave. The reaction time was adjusted to reach the desired softening point, and after completion of the reaction, the product was taken out of the container, cooled and pulverized to obtain binder resin 1 for toner particles. The softening point of the binder resin 1 was 130°C, and the glass transition temperature Tg was 57°C.The softening point was measured as described below.Measurement of softening pointThe softening point is measured with a capillary rheometer of a constant pressure extrusion system under load, Flow Tester CFT-500D (manufactured by Shimadzu) according to the instruction attached to the tester. In this apparatus, the measurement sample is heated and melted in a cylinder while a constant load is applied to the measurement sample by a piston, and the molten sample is extruded from the cylinder. With this apparatus, a rheogram showing the relationship between the downward movement of the plunger and the heating temperature at that time can be prepared.The melting temperature according to method 1 / 2 described in the instructions supplied to the flow tester CFT-500D is defined as the softening point.The melting temperature obtained by the 1 / 2 method is obtained as described below.First, half, X, of the difference between the piston downward displacement Smax at the time when the sample has completely leaked and the piston downward displacement Smin at the time when the sample has started flowing is calculated (i.e., X=(Smax-Smin) / 2). The temperature in the rheogram at which the downward displacement of the piston corresponds to the sum of X and Smin in the rheogram is defined as the melting temperature determined by the 1 / 2 method.For this measurement, about 1.3 g of a sample is compressed into a cylindrical tablet having a diameter of about 8 mm in a tablet forming machine (e.g., NT-100H from NPa System) at about 10 MPa for a period of 60 seconds in an environment of 25° C. This tablet is used as the measurement sample. The measurement with the CFT-500D is carried out under the following conditions:Measurement mode: temperature riseStarting temperature: 50°CEndpoint temperature: 200° CMeasurement intervals: 1.0° CRate of temperature rise: 4.0°C / minCross-sectional area of the flask: 1.000 cm 2Test load (piston load): 10.0 kgf / cm 2(0,9807 MPa)Preheating time: 300 secHole diameter in die: 1.0 mmDie length: 1.0 mmProduction Example of Composite Fine Particles 11. Hydrolysis and condensation polymerization step:(1) In a 500 mL beaker were placed 21.6 g of RO water, 135.0 g of methanol, 0.004 g of acetic acid as a catalyst, and 12.2 g of dimethyldimethoxysilane, and stirred at 45° C. for 5 minutes.(2) To the resulting mixture were added 2.0 g of 28% ammonia water, 15.0 g of tetraethoxysilane, and 5.0 g of aqueous colloidal silica dispersion liquid A (40% by mass of silica solids, number-average silica particle diameter: 40 nm (0.04 μm)), and stirred at 30° C. for 3.0 hours to obtain a crude solution.2. Particle Formation Step:120,0 g of RO water was poured into a 1000 mL beaker, and the raw material solution obtained in the above hydrolysis and condensation polymerization step was dropped for 5 minutes while the RO water was stirred at 25° C. Subsequently, the resulting mixture was heated to 60° C. and stirred for 1.5 hours while maintaining the temperature at 60° C. to obtain a dispersion liquid of external additive fine particles.3. Hydrophobization step:Hexamethyldisilazane having a weight of 6.0 g as a hydrophobicizing agent was added to the dispersion liquid of the dispersion liquid of the external additive fine particles obtained by the particle forming step, and stirred at 60° C. for 3.0 hours. The dispersion was allowed to stand for 5 minutes to allow the powder to settle under the solution. The precipitated powder was collected by suction filtration and dried at 120° C. under reduced pressure for 24 hours to obtain the composite fine particles 1. The number-average primary particle diameter of the composite fine particles 1 was 0.12 μm.Production Example of Composite Fine Particles 2Composite fine particles 2 were produced in the same manner as in the production example of composite fine particles 1, except that 27.2 g of trimethoxymethylsilane was added instead of dimethyldimethoxysilane in (1) of the above hydrolysis and polycondensation step and tetraethoxysilane in (2) was not added.Production Example of Composite Fine Particles 3Composite fine particles 3 were produced in the same manner as in the production example of composite fine particles 1, except that in the hydrolysis and polycondensation step described above, the amount of dimethyldimethoxysilane in (1) was added to 5.4 g, the amount of tetraethoxysilane in (2) was added to 8.2 g, and 13.6 g of trimethoxymethylsilane.Production Example of Composite Fine Particles 4Composite fine particles 4 were produced in the same manner as in the production example of composite fine particles 1, except that in (2) of the above hydrolysis and polycondensation step, an alumina aqueous dispersion liquid (30 mass % of alumina solids, number-average alumina particle diameter: 40 nm (0.04 μm)) was used instead of the silica aqueous colloidal dispersion liquid A.Production Example of Composite Fine Particles 5Composite fine particles 5 were produced in the same manner as in the production example of composite fine particles 1, except that in the hydrolysis and polycondensation step described above, the amount of dimethyldimethoxysilane in (1) was changed to 5.4 g, tetraethoxysilane added in (2) was not added, and 21.8 g of trimethoxymethylsilane was added.Production Example of Composite Fine Particles 6Composite fine particles 6 were prepared in the same manner as in the preparation example of composite fine particles 1 except that the amount of the aqueous colloidal silica dispersion liquid A in (2) of the above hydrolysis and polycondensation step was changed to 10.0 g.Production Example of Composite Fine Particles 7Composite fine particles 7 were produced in the same manner as in the production example of composite fine particles 1, except that in (2) of the above-described hydrolysis and polycondensation step, the amount of 28% ammonia water was changed to 1.0 g and the stirring temperature was changed to 40° C.Production Example of Composite Fine Particles 8Composite fine particles 8 were produced in the same manner as in the production example of composite fine particles 1, except that in (2) of the above-described hydrolysis and polycondensation step, an aqueous colloidal silica dispersion liquid B (40 mass % silica solids, number-average silica particle diameter: 20 nm (0.02 μm)) was used instead of the aqueous colloidal silica dispersion liquid A, the amount of 28% ammonia water was changed to 3.0 g, and the stirring temperature was changed to 25° C.Production Example of Composite Fine Particles 9Composite fine particles 9 were produced in the same manner as in the production example of composite fine particles 1, except that in (2) of the above-described hydrolysis and polycondensation step, aqueous colloidal silica dispersion liquid C (40 mass % silica solids, number-average silica particle diameter: 10 nm (0.01 μm)) was used instead of the aqueous colloidal silica dispersion liquid A, the amount of 28% ammonia water was changed to 3.0 g, and the stirring temperature was changed to 25° C.Production Example of Composite Fine Particles 10The composite fine particles 10 were obtained in the same manner as in the preparation example of the composite fine particles 1, except that in (2) of the above-described hydrolysis and polycondensation step, the amount of 28% ammonia water was changed to 1.0 g, the stirring temperature was changed to 40° C., and the stirring time was changed to 3.5 hours.Production Example of Composite Fine Particles 11Composite fine particles 11 were produced in the same manner as in the production example of composite fine particles 1, except that in (2) of the above-described hydrolysis and polycondensation step, an aqueous colloidal silica dispersion liquid C (40 mass % silica solids, number-average silica particle diameter: 10 nm (0.01 μm)) was used instead of the aqueous colloidal silica dispersion liquid A, the amount of 28% ammonia water was changed to 1.0 g, the stirring temperature was changed to 45° C., and the stirring time was changed to 4.0 hours.Production Example of Composite Fine Particles 12Composite fine particles 12 were produced in the same manner as in the production example of composite fine particles 1, except that in (2) of the above-described hydrolysis and polycondensation step, the amount of 28% ammonia water was changed to 5.0 g, the stirring temperature was changed to 25° C., and the stirring time was changed to 2.0 hours.Production Example of Composite Fine Particles 13In a 250 mL round bottom four-necked flask equipped with a stirring motor, a condenser, and a thermocouple, 18.7 g of colloidal silica dispersion liquid (40 mass % silica solids, number-average silica particle diameter: 30 nm (0.03 μm)), 125 mL of DI water, and 16.5 g (0.066 mol) of methacryloxypropyltrimethoxysilane were added. The temperature was raised to 65°C and the mixture was stirred at 120 U / min. The mixture was bubbled through by introducing nitrogen gas into the mixture for 30 minutes. After 3 hours, 0.16 g of 2,2'-azobisisobutyronitrile free radical initiator dissolved in 10 mL of ethanol was added and the temperature was raised to 75 °C.The radical polymerization was carried out for 5 hours, and then 3 ml of 1,1,1,3,3,3-hexamethyldisilazane was added to the mixture. The reaction was continued for an additional 3 hours. The final mixture was filtered through a 170 mesh screen to remove solidified matters, and the resulting dispersion was dried overnight at 120° C. in a Pyres dish (registered trademark) to obtain composite fine particles 13.The physical properties of the composite fine particles 1 to 13 are shown in Table 1. Table 1 Table 110,121,350,450,000,551,000,550,45Silica0,04650,250,3320,121,350,001,000,001,001,000,00Silica0,04650,250,3330,121,350,300,500,201,000,700,30Silica0,04650,250,3340,121,350,450,000,551,000,550,45Alumina0,04650,250,3350,121,350,000,800,201,001,000,00Silica0,04650,480,3360,121,550,450,000,551,000,550,45Silica0,04650,250,3370,061,350,450,000,551,000,550,45Silica0,04650,250,6780,301,350,450,000,551,000,550,45Silica0,02650,250,0790,301,350,450,000,551,000,550,45Silica0,01650,250,03100,051,350,450,000,551,000,550,45Silica0,04650,250,80110,021,350,450,000,551,000,550,45Silica0,01200,250,50120,331,350,450,000,551,000,550,45Silica0,04650,250,12130,121,50------Silica0,04650,850,33Production Example of Fine Particles C1The hydrated titanium oxide slurry prepared by hydrolyzing an aqueous titanyl sulfate solution was washed with an alkaline aqueous solution until the electric conductivity of the supernatant reached 50 μS / cm to reduce impurities for purification. Then, hydrochloric acid was added to the hydrated titanium oxide slurry to adjust the pH to 0.7 and obtain a titanium dioxide sol dispersion liquid.Strontium chloride aqueous solution was added to 2.2 moles (based on titanium dioxide) of the titanium dioxide sol dispersion liquid in a 1.3 mole times amount of the titanium dioxide sol dispersion liquid, and the mixture was placed in a reaction vessel, followed by purging with nitrogen. In addition, pure water was added so that the concentration of the dispersion liquid relative to titanium oxide was 1.1 mol / L.After stirring and mixing the contents in the reaction vessel and heating the contents to 90°C, 440 mL of a 10N sodium hydroxide aqueous solution was added over 15 minutes under ultrasonic vibration, followed by a 20 minute reaction. After the reaction, pure water having a temperature of 5°C was added to the slurry to rapidly cool the slurry to 30°C or less, and then the supernatant liquid was removed. In addition, an aqueous hydrochloric acid solution having a pH of 5.0 was added to the slurry, and the slurry was stirred for 1 hour to dissolve and remove strontium carbonate, followed by repeated washing with pure water.After adding aqueous hydrochloric acid solution having a pH of 3.0 to the slurry, 7.0 parts by mass of isobutyltrimethoxysilane was then added per 100 parts by mass of solids in the slurry, followed by stirring for 10 hours. The contents of the reaction vessel were then neutralized with an aqueous sodium hydroxide solution, filtered through a suction filter and washed with pure water. The resulting cake was dried to obtain fine particles C1. Physical properties are shown in Table 2.Production Examples of Fine Particles C2 to C8Fine particles C2 to C8 were prepared in the same manner as in the preparation example of fine particles C1, except that the preparation conditions were varied so that the number average particle diameters were the same as those shown in Table 2 and the amount of isobutyltrimethoxysilane added was adjusted. Table 2 Table 21350,3372,0 × 10 102200,36132,5 × 10 103500,28103,5 × 10 114500,50121,2 × 10 125500,23144,7 × 10 126600,21161,4 × 10 1371000,18161,2 × 10 1381100,55175,0 × 10 13Production Example of Fine Particles C9Ilmenite ore containing 50% by mass of TiO 2- equivalent was used as the starting material. The starting material was dried at 150°C for 2 hours and then dissolved by adding sulfuric acid to prepare an aqueous solution of TiOSO 2. The resulting aqueous solution was neutralized to pH 9.0 with an alkali by addition of sodium carbonate and filtered to obtain a white precipitate. The white precipitate was hydrolyzed by addition of pure water and heat-treated at a temperature of about 90°C for 2.5 hours, followed by repeating filtration and washing with water to obtain anatase titanium dioxide.The resulting anatase titanium dioxide was sintered by heating at a high temperature of 1100°C to obtain rutile titanium dioxide. The rutile titanium dioxide was crushed by a jet mill to obtain titanium dioxide fine particles. The titanium oxide fine particles thus obtained were dispersed in ethanol, and 5 parts by mass of isobutyltrimethoxysilane solids as a hydrophobicizing agent was dropped into and mixed with 100 parts by mass of the titanium oxide fine particle dispersion while sufficiently stirring to prevent agglomeration of the particles, thereby performing a hydrophobic treatment reaction.The pH of the slurry was adjusted to 6.5 with further sufficient agitation. After filtering and drying the slurry, the resultant mass was heat-treated at 170°C for 2 hours and then repeatedly crushed with a jet mill until aggregates of titanium oxide were removed to obtain fine particles C9.The fine particles C 9 had a volume resistivity of 2.0×10 9 Ω·cm, and a number-average primary particle diameter of 30 nm.Production Example of Fine Particles C10Titanium tetraisopropoxide used as a raw material was gradually added to the glass wool in a vaporizer heated to about 200°C with a chemical pump using nitrogen gas as a carrier gas for vaporization, followed by immediate thermal decomposition at about 300°C in the reactor and rapid cooling, and thus the product was collected. The resultant product was fired at about 300°C for 2 hours and pulverized in a jet mill to obtain titanium oxide.In 100 parts by mass of water, 52 parts by mass of the above titanium dioxide and 48 parts by mass of calcium carbonate were dispersed and well mixed. The mixture was heat-treated at about 1000°C to obtain calcium titanate fine particles.The resulting calcium titanate fine particles were dispersed in ethanol, and 3 parts by mass of isobutyltrimethoxysilane solids as a hydrophobicizing agent were dropped into and mixed with 100 parts by mass of the dispersion of calcium titanate fine particles while sufficiently stirring to prevent particle agglomeration, thereby performing a hydrophobic treatment reaction.The pH of the slurry was adjusted to 6.5 with further sufficient agitation. After filtering and drying the slurry, the resultant mass was heat-treated at 170° C. for 2 hours and then repeatedly crushed with a jet mill until aggregates of calcium titanate fine particles were removed to obtain fine particles C 10.The fine particles C 10 had a volume resistivity of 3.6×10 13 Ω·cm, and a number-average primary particle diameter of 60 nm.Production Example of Toner 1Binder resin 1: 100 parts by massparaffin wax (melting point 78° C.): 4 parts by massC. I. Pigment Blue 15:3:4 parts by massThe above materials were premixed with a Henschel mixer (trade name: FM-10C, manufactured by Nippon Coke & Engineering), and then the mixture was melted and kneaded at 160° C. with a twin-screw extruder.The resultant kneaded product was cooled and roughly crushed with a hammer mill, and then pulverized with a turbo mill.The pulverized product was classified with a multi-class classifier using the Coanda effect to obtain toner base particles 1 having a weight-average particle size (D4) of 6.5 μm.Toner base particles 1 were subjected to the following external addition.Toner Base Particles 1: 100 parts by massComposite fine particles 1: 8.0 parts by massfine particles C1: 1.3 parts by massThe above materials were mixed with a Henschel mixer (model name: FM-10C, manufactured by Nippon Coke Co., Ltd.) at a rotation speed of 67 sec -1(4000 U / min), a rotation time of 2 min, and an external addition temperature of room temperature, and the mixture was passed through an ultrasonic vibration screen having an opening of 54 μm to obtain Toner 1.Preparation Examples of Toners 2 to 16Toners 2 to 16 were prepared in the same manner as in the preparation example of Toner 1, except that the formulations and conditions for the external additives and their addition amounts were as shown in Table 3. Table 3 Table 3118,011,3Strontium titanate titanate3,4228,011,3Strontium titanate titanate3,4332,020,2Strontium titanate titanate6,0449,031,4Strontium titanate titanate2,4551,030,05Strontium titanate titanate2,46510,032,0Strontium titanate titanate2,47610,042,0Strontium titanate titanate2,48610,052,0Strontium titanate titanate2,49715,060,03Strontium titanate titanate1,01080,572,2Strontium titanate titanate3,01180,5102,2Calcium titanate5,012920,092,2Titanium oxide10,013100,192,2Titanium oxide1,714110,182,2Strontium titanate titanate0,2151222,022,2Strontium titanate titanate16,5161310,082,2Strontium titanate titanate1,1Production Example of Support 1magnetite 1 having a number average particle diameter of 0.30 μm (magnetization intensity of 65 Am 2 / kg under a magnetic field of 1000 / 4π (kA / m))magnetite 2 having a number average particle diameter of 0.50 μm (magnetization intensity of 65 Am 2 / kg under a magnetic field of 1000 / 4π (kA / m))The fine particles of each of the above magnetites were treated by adding 4.0 parts of a silane compound ([3-(2-aminoethylamino)propyl]trimethoxysilane) to 100 parts of the fine particles and mixing them by high-speed stirring at 100°C or more in a container.phenol: 10 mass %formaldehyde solution (40 mass % formaldehyde, 10 mass % methanol, 50 mass % water): 6 mass %Magnetite 1 treated with the above silane compound: 58% by massMagnetite 2 treated with the above silane compound: 26 mass%In a flask were placed 100 parts of the above materials, 5 parts of a 28% by mass ammonia solution, and 20 parts of water, and the temperature was raised to 85° C. for 30 minutes with stirring and mixing. While maintaining the temperature, a polymerization reaction was carried out for 3 hours to cure the produced phenol resin. After the cured phenol resin was cooled to 30°C, water was added and the supernatant liquid was removed. The sediment was rinsed with water and air dried. Then, the resulting substance was dried at 60 °C under reduced pressure (5 mmHg or less) to obtain a spherical magnetic dispersant-containing carrier 1. The volume average median particle size (D50) was 34.2 μm.EXAMPLE 1Preparation of Two-Component Developer 1Toner 1 and carrier 1 were charged in a V-type mixer (V-10 manufactured by Tokuju Corporation) in a proportion where the content of toner was 8.0 mass %, and mixed at 0.5 sec -1 and a rotation time of 5 min to prepare two-component developer 1.EvaluationThe resulting two-component developer 1 was evaluated by the following image forming apparatus. Two-component developer 1 was evaluated as A in each test.The two-component developer 1 was added to the cyan developer of an image forming apparatus, the modified Canon full color copying machine imageRUN ADVANCE C5560 (copying speed: A4 60 sheets / minute), the cyan toner bottle was charged with toner 1, and thus the evaluation was performed as described below.For the evaluation, white sheets (product code: CS-814, A4, 81.4 g / m 2), available from Canon Marketing Japan, were used as the test paper.Evaluation of toner scatteringAfter FFH plots were output at a ratio of 30% to 100000 sheets in a high temperature and high humidity environment (30°C, 80% rF), the apparatus was left for 24 hours.After FFH print-out charts were output at a ratio of 70% in the same environment on 5000 sheets, the degree of toner scattering inside the apparatus was visually observed.A: Scattering was hardly observed.B: Some scattering was observed only around the feed port.C: Scattering was observed around the supply port and its vicinity.D: Toner was scattered around and in the vicinity of the supply opening and also easily onto a part of the intermediate transfer member.E: The toner was scattered around the supply opening and the vicinity thereof and also on a part of the intermediate transfer member.(However, none of these values is so high that the toner is scattered outside the copier.).Evaluation of dot reproducibilityDot reproducibility was evaluated by printing a 1-dot isolated halftone image on an A4 sheet after outputting FFH printout images at a ratio of 30% to 100000 sheets in a high-temperature and high-humidity environment. The area of 1000 points on the image was measured with a digital microscope VHX-500 (wide-angle zoom lens VH-Z100 manufactured by Keyence). The number-average dot area (S) and the standard deviation (σ) of the dot area were calculated, and the dot reproduction index was determined from the following equation.The smaller the dot reproduction index (I), the better the dot reproducibility.A: I was less than 2.0.B: I was 2.0 to less than 3.0.C: I was 3.0 to less than 5.0.D: I was 5.0 to less than 7.0.EXAMPLES 2 TO 13, COMPARATIVE EXAMPLES 1 to 3Preparation of Two-Component Developers 2 to 11Two-component developers 2 to 13 were prepared in the same manner as the two-component developer 1, except that the toner 1 was replaced with the toners 2 to 13.Next, evaluations were carried out in the same manner as in Example 1 except for using the two-component developers 2 to 13.The results are shown in Table 4. Table 4 Table 4Example 11A. AA (1,4)Example 22A. AA (1.5)Example 33A. AA (1.5)Example 44A. AA (1.8)Example 55A. AB (2.2)Example 66A. AB (2.2)Example 77B. BB (2.5)Example 88B. BB (2,6)Example 99B. BC (3.5)Example 1010B. BC (3.6)Example 1111B. BC (3.6)Example 1212C. CC (4,3)Example 1313C. CC (4,7)Comparative Example 114C. CD (5.5)Comparative Example 215E. ED (5.8)Comparative Example 316D. DD (6.2)Although the present disclosure has been described with reference to exemplary embodiments, the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be construed as broadly as possible to include all such modifications and equivalent structures and functions.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedJP 2022-28076 [0003, 0005]

Claims

A toner comprising: toner particles; and an external additive on the surfaces of the toner particles, wherein the external additive includes: composite fine particles including fine particles A containing an organic silicon compound having siloxane bonds as a binder component and fine particles B being on the surfaces of the composite fine particles in a state of being at least partially embedded in the surfaces of the fine particles A, and fine particles C including either titanium oxide fine particles or titanic acid compound fine particles and having a volume resistivity of 2.0×10 9 Ω·cm to 2.0×10 13 Ω·cm and a number average primary particle diameter of 10 nm to 100 nm, wherein the fine particles A satisfy the following relations (1) to (3): Pa + Pb + Pc ≥ 0.80; Pb + Pc ≥ 0.30; and Pa / (Pa + Pb + Pc ) ≤ 0.70, wherein Pa represents the proportion of silicon atoms expressed as Si a, in the structure represented by the following unit (a) with respect to the total silicon atoms contained in the organic silicon compound, Pb represents the proportion of silicon atoms expressed as Si b, in the structure represented by the following unit (b) with respect to the total silicon atoms contained in the organic silicon compound, and Pc represents the proportion of silicon atoms expressed as Si c, in the structure represented by the following unit (c) relative to silicon atoms contained in the organic silicon compound as a whole: wherein R 1 and R 2 each represent an alkyl group having 1 to 6 carbon atoms, the average of the embedding rate of the fine particles B in the fine particles A represented by the following equation is 30% to 90 %: embedding rate (%) of the fine particles B = (depth of embedding of fine particles B in fine particles A) / (diameter of the fine particles B)×100, and the number-average primary particle diameter X of the composite fine particles and the number-average primary particle diameter Y of the fine particles C satisfy the relationship: 1.0≤X / Y≤10.

0. The toner according to claim 1, wherein the number-average primary particle diameter of the composite fine particles is 0.03 μm to 0.30 μm.The toner according to claim 1 or 2, wherein the ratio BD / AD of the number average primary particle diameter BD of the fine particles B to the number average primary particle diameter AD of the fine particles A is in the range of 0.05 to 0.70.The toner according to any one of claims 1 to 3, wherein the fine particles A have an absolute specific gravity of 1.00 g / cm 3 to 1.60 g / cm 3.The toner according to any one of claims 1 to 4, wherein for an electron micrograph of cross sections of the fine particles A taken using a transmission electron microscope, the average of the Sb / Sa values of 100 fine particles A is 0 to 0.50, where Sa is the area of the cross section X of an individual fine particle A and Sb is the total area of the fine particles B contained entirely within the cross section X without being exposed to the outside.The toner according to any one of claims 1 to 5, wherein the fine particles B are silica fine particles or alumina fine particles.The toner according to any one of claims 1 to 6, wherein the fine particles C are titanic acid compound fine particles.The toner according to any one of claims 1 to 7, wherein the fine particles C contain strontium titanate and have a CuKα X-ray diffraction spectrum having the highest peak at a diffraction angle 2θ of 32.00 degrees to 32.40 degrees, and the highest peak has a half width of 0.23 degrees to 0.50 degrees.The toner according to any one of claims 1 to 8, wherein the amount of the fine particles C is 0.05 parts to 2.0 parts by mass with respect to 100 parts by mass of the toner particles.