toner

Abstract

To provide a toner that has excellent durability and can prevent fogging even when applied to a high-speed electrophotographic image forming process.SOLUTION: A toner contains a toner particle and an external additive on the surface of the toner particle. The external additive contains an aggregate of silica fine particles surface-treated with silicone oil. The number average particle diameter Rb of the aggregate of the silica fine particles is 12 nm or more and 80 nm or less. In 29Si- solid NMR of the silica fine particles, when A is the integrated value of a D unit determined when the integrated value of a Q unit in CP / MAS measurement is 100, A is 120 or more and 300 or less. The number-based coefficient of variation of the particle diameter of the aggregate of the silica fine particles is 1.00 or more and 3.00 or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE This disclosure relates to toners used in imaging processes such as electrophotography. [Background technology]

[0002] In recent years, as the purposes and environments of use of image forming devices such as copiers and printers have become more diverse, there has been a demand for even faster speeds, higher image quality, and greater stability. Electrophotography involves a charging step in which a latent electrostatic image carrier (hereinafter referred to as a photoreceptor) is charged by a charging means, an exposure step in which the charged latent electrostatic image carrier is exposed to light to form an electrostatic latent image, and a development step in which the electrostatic latent image is developed with toner to form a toner image. The toner image is then transferred to a recording material with or without an intermediate transfer member, and a fixing step in which the recording material carrying the toner image is heated and pressurized by passing it through a nip formed by a pressure member and a rotatable image heating member, resulting in an output image.

[0003] In order to respond to the recent trend of higher speed, longer life, and energy saving, it is important to optimize each process. Among these, the development process, which has been used until now to form a toner image by developing an electrostatic latent image with toner, is particularly important for higher speed and longer life, while sufficient fixing at low temperatures is important for energy saving. As a means for improving durability, studies have been conducted from the viewpoint of improving external additives in the toner. Patent Document 1 discloses a toner whose durability has been improved by improving the state of the external additives in the toner. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2016-142760 Summary of the Invention [Problem to be solved by the invention]

[0005] According to the study by the present inventors, it was confirmed that the toner disclosed in Patent Document 1 has excellent low-temperature fixing ability and durability. However, it was recognized that there is still room for improvement in order to achieve the longevity of the image forming process in recent years. Specifically, in a durability test, fog occurred when the remaining amount of toner became very low, and furthermore, a phenomenon was observed in which a fogged image with noticeable unevenness was output. The present disclosure is directed to providing a toner that is excellent in durability and can suppress fogging even when applied to a high-speed electrophotographic image forming process. [Means for solving the problem]

[0006] The present disclosure provides a toner containing toner particles and an external additive on the surface of the toner particles, the external additive contains silica fine particles surface-treated with silicone oil, The silica fine particles surface-treated with the silicone oil contain aggregates and non-aggregates, the proportion of the number of aggregates of the silica fine particles is 40% or more based on the total number of aggregates of the silica fine particles and the number of non-aggregates of the silica fine particles; a total content of the aggregates of the silica fine particles and the non-aggregates of the silica fine particles is 0.10 parts by mass or more and 4.00 parts by mass or less with respect to 100 parts by mass of the toner particles, the number-average particle size Rb of the aggregates of the silica fine particles is 12 nm or more and 80 nm or less; The silica fine particles 29 In Si-solid state NMR, when the integral value of the D unit obtained when the integral value of the Q unit in the CP / MAS measurement is set to 100 is defined as A, A is 120 or more and 300 or less, the coefficient of variation of particle diameter based on the number of aggregates of the silica fine particles is 1.00 or more and 3.00 or less; The toner relates to the modified silicone oil, which is a modified silicone oil represented by the following formula (B): JPEG0007735106000001.jpg23108 (In formula (B), R1 is a carbinol group, a hydroxy group, an epoxy group, a carboxy group, an alkyl group, or a hydrogen atom, R 2 is a carbinol group, a hydroxyl group, an epoxy group, or Carboxy Based on be. m is the average number of repeating units, and the modified silicone oil represented by formula (B) has a kinematic viscosity of 20 mm at 25°C. 2 / s~1000mm 2 / s.) [Effects of the Invention]

[0007] According to the present disclosure, it is possible to provide a toner having excellent durability even when applied to a high-speed electrophotographic image forming process. As a result, a toner capable of suppressing fogging can be obtained. [Brief explanation of the drawings]

[0008] [Figure 1] Schematic diagram showing an example of the processing state of silica fine particles [Figure 2] Schematic diagram showing an example of an aggregate of silica fine particles [Figure 3] Schematic diagram showing an example of a mixing treatment device [Figure 4] Schematic diagram showing an example of the configuration of a stirring member [Figure 5] Schematic diagram of silica particle measurement [Figure 6] FIG. 1 is a diagram illustrating an example of an image forming apparatus. DETAILED DESCRIPTION OF THE INVENTION

[0009] In the present disclosure, unless otherwise specified, the expressions "XX or more and YY or less" or "XX to YY" representing a numerical range mean a numerical range including the lower and upper limits, which are the endpoints. When a numerical range is described in stages, the upper and lower limits of each numerical range can be combined in any way.

[0010] To improve the durability of the toner, for example, there is a method of selecting an external additive to be used in the toner and controlling the state of the external additive in the toner. Specifically, by using a large amount of an inorganic external additive with a small particle size, the fluidity of the toner is improved, and as a result, the durability of the toner tends to be improved.

[0011] However, problems can arise from the viewpoint of changes in the state of external additives in the toner during the durability test. When the toner on the developing roller is rubbed by the developing blade, the external additives in the toner may become buried or aggregated external additives may become loosened. This toner is commonly referred to as "degraded toner." Compared to the toner before the durability test, the state of the external additives in the degraded toner has changed, and therefore the charging properties also tend to decrease.

[0012] If the deteriorated toner, whose external additives have changed state, is not developed, it will remain on the developing roller. As this process is repeated, a large amount of deteriorated toner will be present on the developing roller. In the latter half of the durability test, when the remaining toner becomes low, a large amount of more deteriorated toner is likely to remain on the developing roller. At this time, a phenomenon may occur in which relatively undegraded toner in the toner cartridge container mixes with the toner on the developing roller.

[0013] In this case, toner with normal chargeability and toner with abnormal chargeability coexist on the developing roller, causing the problem of uneven and noticeable fogged images being output due to the toner with abnormal chargeability. This problem is likely to occur when the remaining toner amount becomes very low during durability tests. This problem is particularly noticeable in toner cartridges that are designed to last longer in recent years and toner cartridges that are designed to have more compact components.

[0014] Therefore, the present inventors have focused on changes in the state of the external additive in the toner during durability testing and conducted extensive research. As a result, they have found that the above requirements can be met well by using an external additive in an aggregated state and maintaining the aggregated state during durability testing. Specifically, they have found that the above requirements can be met well by adhering silica fine particles having a relatively high parameter A (described below) to the surface of toner particles in an aggregated state and by making the aggregates uniform in size. That is, the present disclosure relates to the following toner.

[0015] The present disclosure provides a toner containing toner particles and an external additive on the surface of the toner particles, the external additive contains aggregates of silica fine particles that have been surface-treated with silicone oil; the number-average particle size Rb of the aggregates of the silica fine particles is 12 nm or more and 80 nm or less; The silica fine particles 29 In Si-solid-state NMR, when the integral value of the Q unit in the CP / MAS measurement is set to 100 and the integral value of the D unit is set to A, A is 120 or more and 300 or less, The toner has a coefficient of variation of particle diameter based on the number of aggregates of the silica fine particles of 1.00 or more and 3.00 or less.

[0016] As a result of investigations by the present inventors, it has been found that by using the above toner, it is possible to provide a toner that is excellent in durability and can reduce fog at the end of the durability test.

[0017] The toner has toner particles and an external additive on the surface of the toner particles. The external additive contains aggregates of silica fine particles that have been surface-treated with silicone oil. This means that the silica fine particles present on the surface of the toner particles form aggregates. Figure 1 shows a schematic diagram of primary particles of silica fine particles. Figure 2 shows a schematic diagram of an aggregate of silica fine particles. The silica fine particles contained in the toner can be confirmed to be aggregates by detaching them and observing them using the method described below.

[0018] When silica fine particles on the surface of a toner particle form an aggregate, the aggregate of silica fine particles comes into contact with the surface of the toner particle at multiple points, and therefore, when subjected to a force in the direction of embedding, the pressure can be dispersed. Therefore, compared to when silica fine particles exist alone on the surface of a toner particle as primary particles, embedding of the silica fine particles in the toner particle due to rubbing with the developing blade can be suppressed.

[0019] The number-average particle diameter Rb of the silica particle aggregates is 12 nm or more and 80 nm or less. Rb indicates the number-average particle diameter of the silica particle aggregates present on the surface of the toner particles. The Rb of the silica particles contained in the toner can be calculated using the method described below. When Rb is within this range, the toner can achieve good fluidity. This facilitates circulation of the toner on the developing roller and the toner in the toner cartridge container, resulting in less accumulation of degraded toner on the developing roller.

[0020] The number-average particle diameter Rb of the aggregates of silica microparticles is preferably 15 nm or more and 40 nm or less, more preferably 20 nm or more and 30 nm or less. The number-average particle diameter Rb can be increased by increasing the amount of silicone oil in the silica microparticles described below or by using modified silicone oil described below. The number-average particle diameter Rb can also be decreased by decreasing the amount of silicone oil in the silica microparticles.

[0021] Silica microparticles 29 In Si-NMR (solid state), when the integral value of the Q unit in the CP / MAS measurement is set to 100 and the integral value of the D unit is set to A (parameter A), A must be 120 or more and 300 or less.

[0022] The above-mentioned parameter A and the parameters B and A / B to be described later are 29 Calculated by Si-solid state NMR. 29In Si-solid-state NMR, four types of peaks can be observed for silicon atoms in a solid sample: M unit (formula (4)), D unit (formula (5)), T unit (formula (6)), and Q unit (formula (7)). M units: (Ri) (Rj) (Rk) SiO 1 / 2 Formula (4) D units: (Rg)(Rh)Si(O 1 / 2 )2 formula (5) T units: RmSi(O 1 / 2 )3 formula (6) Q units: Si(O 1 / 2 )4 formula (7)

[0023] In the formulas (4), (5), and (6), Ri, Rj, Rk, Rg, Rh, and Rm each represent an alkyl group such as a hydrocarbon group having 1 to 6 carbon atoms bonded to silicon, a halogen atom, a hydroxy group, It represents an acetoxy group, a carbinol group, an epoxy group, a carboxy group, a hydrogen atom, or an alkoxy group.

[0024] 29 Two types of Si-solid-state NMR measurement are used: DD / MAS measurement and CP / MAS measurement. DD / MAS measurement observes all silicon atoms in the measurement sample, thereby providing information on the silicon atom content. When DD / MAS measurement is performed on silica microparticles surface-treated with silicone oil, the Q unit shows a peak corresponding to the original silica microparticles before treatment, and the D unit shows a peak corresponding to the silicone oil used as a treatment agent. That is, if the integral value of the D unit obtained when the integral value of the Q unit in DD / MAS measurement is set to 100 is defined as B (parameter B), parameter B represents the amount of silicone oil relative to the original silica microparticles. For example, the greater the amount of silicone oil present on the surface of the original silica microparticles, the greater the value of B. B is preferably 20 to 60, more preferably 30 to 50.

[0025] On the other hand, in CP / MAS measurements, measurements are taken while magnetizing silicon atoms via hydrogen atoms present near the silicon atoms, so silicon atoms present near hydrogen atoms can be observed with high sensitivity. The presence of hydrogen atoms near silicon atoms means that the molecular mobility of the measurement sample is low. In other words, the lower the molecular mobility of the measurement sample and the greater the amount of molecular mobility, the more sensitively the silicon atoms can be observed. In other words, when CP / MAS measurements are performed on silica microparticles surface-treated with silicone oil, the parameter A contains information not only about the amount of silicone oil relative to the silica microparticle base material, but also about the molecular mobility of the silicone oil. For example, the more silicone oil with low molecular mobility is present on the surface of the silica microparticle base material, the larger the value of A will be.

[0026] As a result of extensive research, the inventors have found that silica microparticles exhibiting a high value for parameter A tend to maintain the shape of the aggregates even when subjected to rubbing by a development blade in a durability test.

[0027] The toner contains aggregates of silica fine particles that have been surface-treated with silicone oil. Therefore, silicone oil is present inside the aggregates of silica fine particles. According to the inventors' research, when the toner is subjected to rubbing with a developing blade in a durability test, the aggregates of silica fine particles break down when the silicone oil has a high degree of freedom. It is presumed that this is because the silicone oil, which has a high degree of freedom and exists inside the aggregates, moves at the molecular level, making the silica fine particles more likely to break apart.

[0028] Therefore, parameter A, which indicates the degree of freedom of the silicone oil of the silica microparticles, is 120 or more and 300 or less, which indicates that the degree of freedom of the silicone oil is low. When parameter A satisfies the above range, the aggregates of the silica microparticles can maintain their shape throughout the durability test, thereby suppressing toner deterioration. When parameter A is less than 120, the aggregates of the silica microparticles tend to have difficulty maintaining their shape throughout the durability test, thereby making it difficult to suppress toner deterioration. When parameter A exceeds 300, the degree of freedom of the silicone oil is too low, making it difficult to control the coefficient of variation (described later) within a specified range.

[0029] The parameter A is preferably 140 or more and 200 or less, more preferably 150 or more and 170 or less. The parameter A can be increased by increasing the amount of modified silicone oil used to treat silica microparticles or by lowering the viscosity of the silicone oil in order to make the silicone oil a low molecular chain. In addition, the parameter A can be decreased by using modified silicone oil and silicone oil in combination.

[0030] The coefficient of variation of particle diameter based on the number of silica fine particle aggregates is 1.00 or more and 3.00 or less. This indicates that the size of the silica fine particle aggregates present on the toner particle surface is relatively uniform. The coefficient of variation can be calculated by desorbing the silica fine particles contained in the toner using the method described below.

[0031] Silica fine particles form aggregates, which can easily cause the aggregates on the surface of toner particles to become trapped within each other. This reduces the fluidity of the toner, hindering the toner on the developing roller from switching over with the toner in the toner cartridge. The inventors have found that by making the aggregates uniform in size, the fluidity of the toner can be maintained at a satisfactory level.

[0032] If the size of the aggregates is not uniform, a phenomenon occurs in which small aggregates get caught in the gaps between larger aggregates, but if the size is uniform, this phenomenon is less likely to occur, which is thought to have resulted in good fluidity. The theoretical lower limit of the coefficient of variation is 1.00, which means that the size of the aggregates is completely uniform.

[0033] On the other hand, if the coefficient of variation is 3.00 or less, the phenomenon of aggregates on the surface of toner particles becoming trapped can be suppressed, thereby maintaining good toner fluidity. As a result, at the end of the durability test, the toner on the developing roller and the toner in the toner cartridge are frequently replaced. This prevents degraded toner from being localized on the developing roller, thereby suppressing uneven fogging at the end of the durability test. The coefficient of variation is preferably 1.20 or more and 2.50 or less, and more preferably 1.45 or more and 2.40 or less.

[0034] Aggregates of silica fine particles with a high parameter A have the property of being difficult to disintegrate during durability tests. However, because these silica fine particles form aggregates that are difficult to disintegrate, when they are added to toner particles, the size of the aggregates on the toner particle surface tends to become uneven. In this case, it becomes difficult for the deteriorated toner on the developing roller to be replaced with toner in the toner cartridge container, and deterioration of the toner on the developing roller may not be suppressed.

[0035] In order to make the size of the aggregates on the toner particle surface uniform, for example, the degree of freedom of the silicone oil, such as the parameter A of the silicone oil or the parameter A / B described later, can be controlled, or a manufacturing method of crushing silica fine particles or a manufacturing method of externally adding silica fine particles while diffusing them can be introduced. Details will be described later.

[0036] The number-average particle size Ra of the primary particles of the silica fine particles is preferably 5 nm or more and 30 nm or less, more preferably 5 nm or more and 15 nm or less, and even more preferably 6 nm or more and 10 nm or less. This means that the size of the primary particles of the silica fine particles is relatively small. When Ra satisfies this range, the toner on the developing roller and the toner in the toner cartridge container tend to be replaced more frequently, thereby preventing the accumulation of degraded toner on the developing roller.

[0037] The number average particle size Ra of the primary particles and the number average particle size Rb of the aggregates of the silica fine particles preferably satisfy the following formula (1), and more preferably satisfy the following formula (1'). 2.5≦Rb / Ra≦5.0 (1) 3.0≦Rb / Ra≦4.0 (1´) This indicates the number of primary particles contained in an aggregate of silica fine particles. When Rb / Ra satisfies formula (1), the aggregate of silica fine particles tends to come into contact with the surface of the toner particle at multiple points, which makes it possible to further prevent the aggregate from sinking during durability tests.

[0038] The external additive further contains non-aggregated silica fine particles surface-treated with silicone oil, and the proportion of the number of aggregated silica fine particles in the total number of aggregated silica fine particles and non-aggregated silica fine particles is preferably 40% by number or more, more preferably 50% by number or more, and even more preferably 65% ​​by number or more. There is no particular upper limit, but it is preferably 99% by number or less, more preferably 95% by number or less.

[0039] The above number ratio indicates the ratio of non-aggregated to aggregated silica fine particles present on the toner particle surface, and means that the ratio of aggregates is relatively high. When the number ratio is 40% or more, the embedding of aggregates in durability tests can be further suppressed. The number ratio of aggregated silica fine particles can be increased by using silica fine particles treated with modified silicone oil, as described below, or by using silica fine particles with a high A value. In addition, the number ratio of aggregated silica fine particles can be reduced by extending the pre-mixing time in the external addition process.

[0040] Silica microparticles 29 In Si-NMR (solid state), when the integral value of the D unit obtained when the integral value of the Q unit in the CP / MAS measurement is set to 100 is A, and the integral value of the D unit obtained when the integral value of the Q unit in the DD / MAS measurement is set to 100 is B, it is preferable that the following formula (2) is satisfied, and it is more preferable that the following formula (2') is satisfied. 3.0 ≦ A / B ≦ 6.0 (2) 3.5 ≦ A / B ≦ 5.0 (2´)

[0041] As mentioned above, parameter A indicates the degree of silicone oil mobility, and parameter B indicates the degree of silicone oil relative to the amount of silica microparticles. Equation (2) indicates the degree of silicone oil mobility relative to the amount of silicone oil contained in the silica microparticles. When A / B satisfies the above range, it becomes easier to control the degree of disintegration of silica microparticle aggregates within a suitable range. In addition, it becomes easier to maintain the shape of the silica microparticle aggregates during durability tests, and it becomes easier to control the coefficient of variation of the particle size of the aggregates within a suitable range.

[0042] (binder resin) The toner particles preferably contain a binder resin. Examples of the binder resin include vinyl resins, polyester resins, epoxy resins, and polyurethane resins. These known resins can be used without any particular limitation. Among them, from the viewpoint of achieving both chargeability and fixability, it is preferable that the toner particles contain at least one resin selected from the group consisting of polyester resins and vinyl resins.

[0043] More preferably, the binder resin contains a vinyl resin. Examples of polymerizable monomers (vinyl monomers) for producing vinyl resins include the following. Examples include styrene and its derivatives, styrene-unsaturated monoolefins, unsaturated polyenes, vinyl halides, vinyl esters, α-methylene aliphatic monocarboxylic acid esters, acrylic acid esters, vinyl ethers, vinyl ketones, N-vinyl compounds, and acrylic acid or methacrylic acid derivatives. Further examples include monomers having a carboxy group, such as unsaturated dibasic acids, unsaturated dibasic acid anhydrides, half esters of unsaturated dibasic acids, unsaturated dibasic acid esters, α,β-unsaturated acids, α,β-unsaturated acid anhydrides, anhydrides of the α,β-unsaturated acids and lower fatty acids, alkenylmalonic acid, alkenylglutaric acid, alkenyladipic acid, acid anhydrides thereof, and monoesters thereof. Further examples include acrylic acid esters and methacrylic acid esters, and monomers having a hydroxy group such as 4-(1-hydroxy-1-methylbutyl)styrene and 4-(1-hydroxy-1-methylhexyl)styrene.

[0044] The vinyl resin may have a crosslinked structure formed by crosslinking with a crosslinking agent having two or more vinyl groups, such as divinylbenzene.

[0045] (coloring agent) The toner particles may contain a colorant. Examples of the colorant include the following: Examples of organic pigments or organic dyes as cyan colorants include copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, and basic dye lake compounds.

[0046] Examples of organic pigments or organic dyes as magenta colorants include the following: condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds.

[0047] Examples of organic pigments or organic dyes as yellow colorants include compounds typified by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds. Examples of black colorants include those toned to black using carbon black, the above yellow colorants, magenta colorants, and cyan colorants. When a colorant is used, it is preferably added in an amount of 1 part by mass or more and 20 parts by mass or less per 100 parts by mass of the polymerizable monomer or binder resin. The toner particles may contain a magnetic material as a black colorant. The magnetic material may also function as a colorant.

[0048] The magnetic material is primarily composed of iron oxide or gamma-iron oxide, and may contain elements such as phosphorus, cobalt, nickel, copper, magnesium, manganese, and aluminum. The magnetic material may be polyhedral, octahedral, hexahedral, spherical, needle-like, or flaky. Shapes with little anisotropy, such as polyhedral, octahedral, hexahedral, or spherical, are preferred for increasing image density. The content of the magnetic material is preferably 50 to 150 parts by mass per 100 parts by mass of the polymerizable monomer or binder resin.

[0049] (wax) The toner particles preferably contain a wax. The wax preferably contains a hydrocarbon wax. Other waxes include the following: amide wax, higher fatty acid, long-chain alcohol, ketone wax, ester wax, and derivatives thereof such as graft compounds and block compounds. Two or more waxes may be used in combination as needed.

[0050] Among these, when a hydrocarbon wax produced by the Fischer-Tropsch process is used, it is possible to maintain good developability for a long period of time and also to maintain good high-temperature offset resistance. Note that these hydrocarbon waxes may contain an antioxidant to the extent that it does not affect the chargeability of the toner. The content of the wax is preferably 4.0 parts by mass or more and 30.0 parts by mass or less, and more preferably 4.0 parts by mass or more and 28.0 parts by mass or less, relative to 100 parts by mass of the binder resin.

[0051] (charge control agent) The toner particles may contain a charge control agent as needed. By blending a charge control agent, the charge characteristics can be stabilized and the amount of triboelectric charge can be controlled to an optimum level according to the development system.

[0052] As the charge control agent, known ones can be used, and in particular, those having a high charging speed and a constant A charge control agent capable of stably maintaining the charge amount is preferred. Furthermore, when the toner particles are produced by a direct polymerization method, a charge control agent that has low polymerization inhibition properties and is substantially free of solubilized substances in an aqueous medium is particularly preferred.

[0053] The toner particles may contain a single charge control agent or a combination of two or more types of charge control agents. The amount of charge control agent blended is preferably 0.3 parts by mass or more and 10.0 parts by mass or less, and more preferably 0.5 parts by mass or more and 8.0 parts by mass or less, per 100 parts by mass of the polymerizable monomer or binder resin.

[0054] (external additives) The toner contains an external additive on the surface of the toner particles. The external additive contains aggregates of silica fine particles that have been surface-treated with silicone oil. By adding the silica fine particles as an external additive to the toner particles, it is possible to achieve improvements in charging stability, durable developing performance, fluidity, and durability.

[0055] Furthermore, other external additives may be added to the toner as needed, such as resin fine particles and inorganic fine particles that function as a charge aid, a conductivity imparting agent, a fluidity imparting agent, an anti-caking agent, a release agent during heat roller fixing, a lubricant, an abrasive, etc.

[0056] Examples of the lubricant include polyethylene fluoride powder, zinc stearate powder, and polyvinylidene fluoride powder. Examples of the abrasive include cerium oxide powder, silicon carbide powder, and strontium titanate powder, with strontium titanate powder being preferred.

[0057] <Silica fine particles> The silica fine particles will be described below. The external additive contains aggregates of silica fine particles that have been surface-treated with silicone oil. Preferably, the external additive contains non-aggregates of silica fine particles that have been surface-treated with silicone oil. Non-aggregates refer to silica fine particles that exist in the state of primary particles.

[0058] Known materials can be used as the silica microparticle raw material, for example, silicon compounds, particularly silicon halides, generally silicon chlorides, fumed silica usually produced by burning purified silicon tetrachloride in an oxyhydrogen flame, wet silica produced from water glass, sol-gel silica particles obtained by a wet method, gel silica particles, aqueous colloidal silica particles, alcoholic silica particles, fused silica particles obtained by a gas phase method, and deflagration silica particles can be mentioned.

[0059] The number-average particle diameter of the primary particles of the silica fine particles before surface treatment with silicone oil is preferably 5 nm or more and 30 nm or less, since this can sufficiently impart high fluidity and high chargeability to the toner. When the number-average particle diameter is 5 nm or more, the embedding of the silica fine particles into the toner particle surface after surface treatment is further suppressed, further improving durability. When the number-average particle diameter is 30 nm or less, good fluidity is obtained.

[0060] Furthermore, it is preferable to use a modified silicone oil as the silicone oil used as a surface treatment agent for silica microparticles. That is, it is preferable that the silicone oil contains a modified silicone oil. When a modified silicone oil is used, the modified silicone oil firmly adheres to the surface of the silica microparticles, thereby reducing the molecular mobility of the modified silicone oil. This makes it easier to control the parameter A within a high range. As a result, it becomes easier to maintain the shape of the aggregates of silica microparticles during a durability test, and the generation of deteriorated toner can be suppressed, thereby further suppressing uneven fogging at the end of the durability test.

[0061] The modified silicone oil is preferably a modified silicone oil having a reactive group at the end of the molecular chain, such as the compound represented by formula (B) below. Silicone oils having a reactive group at the end of the molecular chain form chemical bonds with silanol groups on the surface of the raw silica microparticles before treatment at the end of the molecular chain, reducing the mobility of the silicone oil. As a result, the aggregate shape of the silica microparticles is more easily maintained during durability tests, and the generation of degraded toner is suppressed, thereby further suppressing fog at the end of the durability test. [ka]

[0062] In the formula, R 1 is a carbinol group, a hydroxy group, an epoxy group, a carboxy group, an alkyl group (preferably having 1 to 6 carbon atoms, more preferably having 1 to 3 carbon atoms), or a hydrogen atom, and R 2is a carbinol group, a hydroxy group, an epoxy group, a carboxy group, or a hydrogen atom. 1 and R 2 are respectively a carbinol group, a hydroxy group, or a hydrogen atom. The methyl group on the side chain in formula (B) may be respectively substituted with a carbinol group, a hydroxy group, an epoxy group, a carboxy group, or a hydrogen atom. m is the average number of repeating units, and the kinematic viscosity of the modified silicone oil at 25°C is 20mm 2 / s~1000mm 2 / s (preferably 25 to 200 mm 2 / s, more preferably 30 to 70 mm 2 / s). For example, m is 30 or more and 200 or less (preferably 40 to 100, more preferably 50 to 80).

[0063] More preferably, a modified silicone oil having hydroxy groups at both ends, as shown in formula (D) below, is used. The hydroxy groups at the molecular chain end form strong siloxane bonds with silanol groups on the surface of the silica microparticles. This reduces the molecular mobility of the modified silicone oil adhered to the surface of the silica microparticles. This makes it easier to maintain the shape of the silica microparticle aggregates during durability tests, suppresses the generation of degraded toner, and further reduces fogging at the end of the durability test. [ka]

[0064] In formula (D), p is the average number of repeating units, and the kinematic viscosity of the modified silicone oil at 25°C is 20 mm 2 / s~1000mm 2 / s (preferably 25 to 200 mm 2 / s, more preferably 30 to 70 mm 2 / s). For example, p is 30 or more and 200 or less (preferably 40 to 100, more preferably 50 to 80). Furthermore, by using polydimethylsiloxane as shown in the following formula (A) in combination with the modified silicone oil, the silica fine particles are sufficiently hydrophobicized, thereby further improving the chargeability. [ka]

[0065] n is the average number of repeating units, and the kinematic viscosity of the polydimethylsiloxane at 25°C is 20mm 2 / s~1000mm 2 / s (preferably 25 to 200 mm 2 / s, more preferably 30 to 70 mm 2 / s). For example, n is 30 or more and 200 or less (preferably 40 to 100, more preferably 50 to 80). The treatment of silica fine particles with silicone oil can be carried out by a known wet or dry method, and it is preferable to carry out the treatment using these methods in a state where the silica fine particles are dispersed so that the silica fine particles have a mechanically appropriate agglomerated size.

[0066] The silicone oil represented by formula (B) or formula (A) is preferably highly volatile so that it can be efficiently evaporated and removed by the surface treatment described below. For this reason, the silicone oil represented by formula (B) or formula (A) preferably has a relatively small molecular weight. The molecular weight of the silicone oil is correlated with the kinetic viscosity of the silicone oil, and the lower the kinetic viscosity, the lower the molecular weight. Silicone oils with low kinetic viscosity have more reaction sites with silica microparticles, so the parameter A of the silica microparticles tends to be high. The kinetic viscosity range at a temperature of 25°C is preferably 20 to 1000 mm 2 / s, and more preferably 25 to 200 mm 2 / s, and more preferably 30 to 70 mm 2 / s.

[0067] The amount of silicone oil used for surface treatment of silica fine particles varies depending on the type of silica fine particles (specific surface area, etc.), the type of silicone oil (molecular weight, etc.), etc. It is preferably 1 to 40 parts by mass, more preferably 2 to 35 parts by mass, and even more preferably 5 to 30 parts by mass, per 100 parts by mass of silica fine particles. By satisfying this range, hydrophobicity can be enhanced and the coefficient of variation can be easily controlled within a specific range.

[0068] (Surface treatment method) The surface treatment method is preferably carried out in an inert gas atmosphere such as a nitrogen atmosphere to prevent hydrolysis and oxidation.Specifically, the raw material of silica microparticles is placed in a container equipped with a stirring device such as a Henschel mixer, stirred under nitrogen purge, and a diluted solution of silicone oil is sprayed and mixed with the raw material of silica microparticles, and then heated to cause reaction.The spraying can be carried out before heating, or can be carried out while heating to the temperature of treatment or lower.

[0069] (Processing conditions) The surface treatment is a treatment in which the predetermined amount of silicone oil is applied to the raw material of silica microparticles and heated under stirring, so that the silicone oil reacts with the surface of the raw material of silica microparticles and is fixed.Here, the silicone oil may be diluted with the various solvents mentioned above and then applied to the raw material of silica microparticles.

[0070] The heating temperature in this surface treatment varies depending on the reactivity of the silicone oil used, but is preferably 150 to 350°C, more preferably 250 to 320°C. The treatment time varies depending on the heating temperature and the reactivity of the silicone oil used, but is preferably 5 to 300 minutes, more preferably 30 to 200 minutes, and even more preferably 60 to 150 minutes. The silicone oil can react sufficiently with the silica microparticles.

[0071] From the viewpoint of improving fluidity and chargeability, the total content of aggregated silica fine particles and non-aggregated silica fine particles is preferably 0.10 parts by mass or more and 4.00 parts by mass or less, more preferably 0.20 parts by mass or more and 3.50 parts by mass or less, even more preferably 0.20 parts by mass or more and 1.00 parts by mass or less, and even more preferably 0.30 parts by mass or more and 0.50 parts by mass or less, relative to 100 parts by mass of toner particles.

[0072] The toner surface may contain inorganic particles other than the silica particles, such as titanium oxide particles, alumina particles, or double oxide particles thereof.

[0073] (Toner manufacturing method) The method for producing toner particles is not particularly limited, and known methods can be used. From the viewpoint of obtaining good fluidity of the toner, it is preferable to produce toner particles in an aqueous medium by a method such as a dispersion polymerization method, an association aggregation method, a solution suspension method, or a suspension polymerization method, and in particular, a suspension polymerization method is preferable.

[0074] The method for producing toner particles using the suspension polymerization method includes a step of dispersing a polymerizable monomer composition containing a polymerizable monomer capable of producing a binder resin and, if necessary, additives such as a colorant, in an aqueous medium to granulate the polymerizable monomer, and a step of polymerizing the polymerizable monomer contained in the granulated particles to obtain toner particles. The polymerizable monomer may be any of those previously described as materials for the binder resin. From the viewpoint of a balance between developability and fixability, the weight-average particle size (D4) of the toner is preferably 5.0 μm or more and 10.0 μm or less, more preferably 6.0 μm or more and 9.0 μm or less.

[0075] When producing by the pulverization method, for example, a binder resin and, if necessary, other additives such as a colorant and a release agent are thoroughly mixed using a mixer such as a Henschel mixer or a ball mill. The toner materials are then melt-kneaded using a thermal kneader such as a heated roll, kneader, or extruder to disperse or dissolve them, and the mixture is cooled, solidified, and pulverized, followed by classification and, if necessary, surface treatment to obtain toner particles. The order of classification and surface treatment is not important. In the classification step, it is preferable to use a multi-division classifier for the sake of production efficiency. The above-mentioned pulverization can be carried out by a method using a known pulverizing device such as a mechanical impact type or a jet type.

[0076] Examples of means for applying mechanical impact force include a method using a mechanical impact crusher such as the Kryptron System manufactured by Kawasaki Heavy Industries, Ltd. or the Turbo Mill manufactured by Turbo Kogyo Co., Ltd. Also included are methods in which mechanical impact force is applied to toner particles by compressive force, frictional force, or the like, using devices such as the Mechanofusion System manufactured by Hosokawa Micron Corporation or the Hybridization System manufactured by Nara Machinery Manufacturing Co., Ltd.

[0077] In the suspension polymerization method, for example, a polymerizable monomer and a colorant (and, if necessary, a polymerization initiator, a crosslinking agent, a charge control agent, and other additives) are uniformly dissolved or dispersed to obtain a polymerizable monomer composition. Then, this polymerizable monomer composition is dispersed in a continuous phase (e.g., an aqueous phase) containing a dispersion stabilizer using an appropriate stirrer, and a polymerization reaction is simultaneously carried out to obtain toner particles having a desired particle size.

[0078] As the polymerizable monomer constituting the polymerizable monomer composition, in addition to the above-mentioned vinyl monomers as examples, known monomers can be used. Among them, it is preferable to use styrene or a styrene derivative alone or in combination with other polymerizable monomers from the viewpoint of the developing characteristics and durability of the toner.

[0079] The polymerization initiator used in the suspension polymerization method preferably has a half-life of 0.5 to 30.0 hours during the polymerization reaction. The amount of the polymerization initiator added is preferably 0.5 to 20.0 parts by mass per 100 parts by mass of the polymerizable monomer. Specific examples of the polymerization initiator include those mentioned above, azo- or diazo-based polymerization initiators, and peroxide-based polymerization initiators.

[0080] In the suspension polymerization method, the crosslinking agent may be added during the polymerization reaction, preferably in an amount of 0.1 to 10.0 parts by mass per 100 parts by mass of the polymerizable monomer.

[0081] Here, the crosslinking agent is preferably a compound having two or more polymerizable double bonds. For example, as described above, aromatic divinyl compounds, carboxylic acid esters having two double bonds, divinyl compounds, and compounds having three or more vinyl groups are preferred. These may be used alone or in combination of two or more.

[0082] The production of toner particles by suspension polymerization will be specifically described below, but is not limited thereto. First, the polymerizable monomer and colorant described above are appropriately added and uniformly dissolved or dispersed using a dispersing machine such as a homogenizer, ball mill, or ultrasonic disperser. The resulting polymerizable monomer composition is then suspended in an aqueous medium containing a dispersion stabilizer and granulated. In this process, using a dispersing machine such as a high-speed agitator or ultrasonic disperser to quickly achieve the desired toner particle size results in a sharper particle size of the resulting toner particles. The polymerization initiator may be added simultaneously with the addition of other additives to the polymerizable monomer, or may be mixed immediately before the polymerizable monomer is suspended in the aqueous medium. Alternatively, the polymerization initiator dissolved in the polymerizable monomer or solvent may be added immediately after granulation and before the polymerization reaction is initiated. After granulation, the mixture may be stirred using a conventional stirrer to such an extent that the particle state is maintained and the particles are prevented from floating or settling.

[0083] As the dispersion stabilizer, known surfactants, organic dispersants, or inorganic dispersants can be used. Among these, inorganic dispersants are preferred because they are less likely to produce harmful ultrafine powders, and because their steric hindrance provides dispersion stability, they are less likely to lose stability even when the reaction temperature is changed, and they are easy to wash. Examples of such inorganic dispersants include polyvalent metal phosphates such as tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, and hydroxyapatite; carbonates such as calcium carbonate and magnesium carbonate; inorganic salts such as calcium metasilicate, calcium sulfate, and barium sulfate; and inorganic compounds such as calcium hydroxide, magnesium hydroxide, and aluminum hydroxide.

[0084] These inorganic dispersants are preferably used in an amount of 0.20 parts by mass or more and 20.00 parts by mass or less per 100 parts by mass of the polymerizable monomer. The dispersion stabilizers may be used alone or in combination. Furthermore, a surfactant may be used in an amount of 0.0001 parts by mass or more and 0.1000 parts by mass or less per 100 parts by mass of the polymerizable monomer. The polymerization temperature in the polymerization reaction of the polymerizable monomer is usually set to 40° C. or higher, preferably 50° C. or higher and 90° C. or lower. After the polymerization of the polymerizable monomer is completed, the obtained polymer particles are filtered, washed, and dried by a known method to obtain toner particles.

[0085] In the drying step, the drying temperature and drying time can be determined while checking the moisture content of the toner particles. From the viewpoint of toner fluidity, the moisture content in the toner is preferably 1.00% by mass or less, more preferably 0.40% by mass or less, even more preferably 0.30% by mass or less, and even more preferably 0.20% by mass or less. There is no particular lower limit, but it is preferably 0.01% by mass or more, and more preferably 0.05% by mass or more.

[0086] The toner is obtained by externally adding and mixing silica fine particles into the obtained toner particles and adhering them to the surface of the toner particles. It is also possible to add a classification process to the manufacturing process (before mixing the silica fine particles) to remove coarse and fine particles contained in the toner particles.

[0087] (External addition process) Although known mixing processing devices can be used as the mixing processing device for externally adding and mixing silica fine particles, a device such as that shown in Figure 3 is preferred in that it can easily control the coefficient of variation of the particle size of the aggregates. Figure 3 is a schematic diagram showing an example of a mixing processing device that can be used when externally adding and mixing silica fine particles.

[0088] The mixing and processing device is configured to apply shear to the toner particles and silica fine particles in a narrow clearance area. This allows the silica fine particle aggregates to adhere to the toner particle surfaces while maintaining a uniform size. This makes it easier to control the coefficient of variation of the particle size of the aggregates within the above range.

[0089] Furthermore, as will be described later, the toner particles and the silica fine particles are easily circulated in the axial direction of the rotor, and are easily mixed uniformly before adhesion progresses, which makes it easy to control the coefficient of variation within a preferred range.

[0090] A known mixing processing device (such as a Henschel mixer) can also be used to mix the toner particles and silica fine particles. The device shown in Figure 3 is preferred because it makes it easier to control the external addition state. In other words, a device like that shown in Figure 3 is configured to easily apply shear to the toner, making it easier to control the coefficient of variation in a short period of time. Meanwhile, Figure 4 is a schematic diagram showing an example of the configuration of a stirring member used in the above mixing processing device. The above external addition and mixing process of silica fine particles will be described below with reference to Figures 3 and 4.

[0091] The mixing treatment device for externally mixing the silica microparticles includes a rotor 2 having at least a plurality of stirring members 3 mounted on its surface, a drive unit 8 (7 indicates the central axis) for rotating the rotor, and a main casing 1 provided with a gap between it and the stirring members 3.

[0092] It is preferable to keep the gap (clearance) between the inner periphery of the main casing 1 and the stirring member 3 constant and small so as to give a uniform shear to the toner particles and make it easier for the silica microparticle aggregates to adhere to the surface of the toner particles while aligning the size of the aggregates.

[0093] Furthermore, in this device, the diameter of the inner periphery of the main casing 1 is no more than twice the diameter of the outer periphery of the rotor 2. Figure 3 shows an example in which the diameter of the inner periphery of the main casing 1 is 1.7 times the diameter of the outer periphery of the rotor 2 (the diameter of the body of the rotor 2 excluding the agitator 3). When the diameter of the inner periphery of the main casing 1 is no more than twice the diameter of the outer periphery of the rotor 2, the processing space in which force acts on the toner particles is appropriately limited, so that sufficient impact force is applied to the silica fine particles that have become secondary particles.

[0094] Furthermore, it is preferable to adjust the clearance according to the size of the main casing. By setting the clearance to approximately 1% to 5% of the diameter of the inner periphery of the main casing 1, sufficient shear force can be applied to the silica microparticles. Specifically, if the diameter of the inner periphery of the main casing 1 is approximately 130 mm, the clearance should be approximately 2 mm to 5 mm, and if the diameter of the inner periphery of the main casing 1 is approximately 800 mm, the clearance should be approximately 10 mm to 30 mm.

[0095] In the external mixing step of silica fine particles, a mixing treatment device is used, and the rotor 2 is rotated by the driving unit 8. The toner particles and silica fine particles introduced into the mixing treatment device are stirred and mixed, whereby the silica fine particles are externally added to the surfaces of the toner particles.

[0096] 4, at least some of the multiple agitating members 3 are formed as feeding agitating members 3a that feed the toner particles and silica fine particles in one axial direction of the rotor 2 as the rotor 2 rotates. Also, at least some of the multiple agitating members 3 are formed as returning agitating members 3b that return the toner particles and silica fine particles in the other axial direction of the rotor as the rotor 2 rotates.

[0097] Here, when the raw material inlet 5 and the product outlet 6 are provided at both ends of the main casing 1 as shown in Figure 3, the direction from the raw material inlet 5 to the product outlet 6 (to the right in Figure 3) is referred to as the "feed direction."

[0098] That is, as shown in Figure 4, the plate surface of the feeding stirring member 3a is inclined so as to feed the toner particles in the feeding direction (13), while the plate surface of the stirring member 3b is inclined so as to feed the toner particles and silica fine particles in the return direction (12).

[0099] As a result, the silica fine particles are externally added and mixed onto the surfaces of the toner particles while repeatedly feeding in the "feeding direction 13" and feeding in the "returning direction 12".

[0100] Furthermore, the stirring members 3a and 3b are each a set of multiple members spaced apart in the circumferential direction of the rotor 2. In the example shown in Fig. 4, the stirring members 3a and 3b are each a set of two members spaced 180 degrees apart on the rotor 2, but the set may also be made up of multiple members, such as four members spaced 120 degrees apart or 90 degrees apart. In the example shown in FIG. 4, a total of 12 stirring members 3a and 3b are formed at equal intervals.

[0101] Furthermore, in FIG. 4, D indicates the width of the agitating member, and d indicates the distance between the overlapping portions of the agitating members. From the viewpoint of efficiently feeding the toner particles and silica fine particles in the forward and return directions, it is preferable that D be approximately 20% to 30% of the length of the rotor 2 in FIG. 4. FIG. 4 shows an example where D is 23%. Furthermore, when a vertical extension line is drawn from the end position of agitating member 3a, it is preferable that agitating members 3a and 3b have a certain degree of overlap d between agitating member 3b and agitating member 3a. This makes it possible to efficiently apply shear to the silica fine particles that have become secondary particles. In terms of applying shear, it is preferable that d be 10% to 30% of D.

[0102] The shape of the blades may be any shape other than that shown in Fig. 4, as long as it can send toner particles in the forward and return directions and maintain clearance. Specifically, the blades may have a curved surface or a paddle structure in which the tip blades are connected to the rotor 2 by a rod-shaped arm.

[0103] The device will be described in detail below with reference to the schematic diagrams of Figures 3 and 4. The device shown in Figure 3 comprises a rotor 2 having at least a plurality of agitating members 3 mounted on its surface, a drive unit 8 that rotates the rotor 2, and a main casing 1 that is spaced apart from the agitating members 3. Furthermore, the device comprises a jacket 4 that is located inside the main casing 1 and on a side surface 10 at the end of the rotor, through which a cooling medium can flow.

[0104] 3 has a raw material inlet 5 formed in the upper part of the main casing 1 for introducing toner particles and silica fine particles, and a product outlet 6 formed in the lower part of the main casing 1 for discharging the toner that has been mixed with external additives from the main casing 1 to the outside.

[0105] Furthermore, in the device shown in FIG. 3, an inner piece 16 for the raw material inlet is inserted into the raw material inlet 5, and an inner piece 17 for the product outlet is inserted into the product outlet 6.

[0106] First, the inner piece 16 for the raw material inlet is removed from the raw material inlet 5, and the toner particles are fed into the processing space 9 through the raw material inlet 5. Next, silica fine particles are fed into the processing space 9 through the raw material inlet 5, and the inner piece 16 for the raw material inlet is inserted. Next, the rotor 2 is rotated by the drive unit 8 (11 indicates the direction of rotation), and the material to be processed fed above is stirred and mixed by the multiple stirring members 3 provided on the surface of the rotor 2, and subjected to an external addition mixing process.

[0107] In order to control the coefficient of variation, which is the size and uniformity of silica microparticle aggregates, it is preferable to divide the external addition mixing process into multiple conditions. Specifically, in order to crush the silica microparticles, the external addition mixing process is performed under conditions that prevent the silica microparticles from adhering to the toner particles, and then the external addition mixing process is performed under conditions that allow the crushed silica microparticles to adhere to the toner particles. In the first external addition mixing process, if the processing conditions are too strong, the crushed silica microparticles will be further crushed, and the proportion of primary particles of the silica microparticles adhering to the toner particle surface will tend to increase.

[0108] More specifically, as a condition for the first external addition mixing process, it is preferable to control the power of the drive unit 8 to 0.2 W / g or more and 0.3 W / g or less, and as a condition for the second external addition mixing process, it is preferable to control the power of the drive unit 8 to 0.2 W / g or more and 0.5 W / g or less. When the first power is 0.2 W / g or more, the agglomerates of silica fine particles can be suitably disintegrated, and the coefficient of variation tends to be easily controlled to a low level.When the first power is 0.3 W / g or less, the silica agglomerates can be sufficiently disintegrated, and the embedding of silica fine particles in the toner particle surface can be suppressed, and the coefficient of variation tends to be easily controlled to a low level. When the second power is 0.2 W / g or more, the silica fine particles are easily attached to the toner particle surface, and good chargeability and flowability are easily obtained.When the second power is 0.5 W / g or less, the silica fine particles are adequately disintegrated, and aggregates of the silica fine particles are easily attached to the toner particle surface.

[0109] The processing time for the first external addition mixing treatment is preferably 1 minute or more and 10 minutes or less. Within this range, the silica fine particles are well disintegrated. The processing time for the second external addition mixing treatment is preferably 4 minutes or more and 20 minutes or less. By satisfying this range, aggregates of silica fine particles can be sufficiently attached to the toner particle surfaces.

[0110] After the external additive mixing process is completed, the inner piece 17 for the product discharge port is removed from the product discharge port 6, and the rotor 2 is rotated by the drive unit 8 to discharge the toner from the product discharge port 6. If necessary, the obtained toner is separated into coarse particles using a sieve such as a circular vibrating sieve to obtain the toner.

[0111] (Image forming device) Next, an example of an image forming apparatus suitable for using toner will be described in detail with reference to FIG. 6. In FIG. 6, reference numeral 100 denotes a photosensitive drum, around which a primary charging roller 117, a developing unit 140 having a developing sleeve 102, a transfer charging roller 114, a cleaner 116, a register roller 124, and the like are provided. The photosensitive drum 100 is charged to, for example, -600 V by the primary charging roller 117 (applied voltages are, for example, AC voltage 1.85 kVpp and DC voltage -620 Vdc). Then, exposure is performed by irradiating the photosensitive drum 100 with laser light 123 from a laser generator 121, and an electrostatic latent image corresponding to the target image is formed. The electrostatic latent image on the photosensitive drum 100 is developed with mono-component toner by the developing unit 140 to obtain a toner image. The toner image is transferred onto a transfer material by a transfer roller 114 abutting against the photosensitive drum via the transfer material. The transfer material carrying the toner image is then conveyed by a conveying belt. The toner is then conveyed to a fixing device 126 by a device such as 125 and fixed onto the transfer material. Although the image forming apparatus shown here uses a magnetic one-component jumping development method, it may use either jumping development or contact development.

[0112] <Measurement of weight average particle size (Dv) of toner> The weight-average particle size (Dv) of the toner is calculated as follows. The measurement device used is a precision particle size distribution measurement device "Coulter Counter Multisizer 3" (registered trademark, manufactured by Beckman Coulter, Inc.) equipped with a 100 μm aperture tube and employing the narrow-pore electrical resistance method. The measurement conditions are set and the measurement data is analyzed using the accompanying dedicated software "Beckman Coulter Multisizer 3 Version 3.51" (manufactured by Beckman Coulter, Inc.). The measurement is performed using an effective number of measurement channels of 25,000. The aqueous electrolyte solution used for the measurement is prepared by dissolving special grade sodium chloride in ion-exchanged water to a concentration of approximately 1% by mass, such as "ISOTON II" (manufactured by Beckman Coulter). Before performing measurements and analysis, the dedicated software is set up as follows.

[0113] In the "Change Standard Measurement Method (SOM)" screen of the dedicated software, set the total count in control mode to 50,000 particles, the number of measurements to 1, and the Kd value to the value obtained using "Standard Particles 10.0 μm" (Beckman Coulter). Press the "Threshold / Noise Level Measurement Button" to automatically set the threshold and noise level. Also, set the current to 1600 μA, the gain to 2, the electrolyte to ISOTON II, and check "Flush aperture tube after measurement." On the "Pulse to particle size conversion setting" screen of the dedicated software, set the bin interval to logarithmic particle size, the particle size bin to 256 particle size bins, and the particle size range from 2 μm to 60 μm. The specific measurement method is as follows.

[0114] (1) Pour approximately 200 ml of the electrolyte solution into a 250 ml round-bottom glass beaker made specifically for the Multisizer 3, set it on the sample stand, and stir the stirrer rod counterclockwise at 24 revolutions per second. Then, use the "aperture tube flush" function of the dedicated software to remove any dirt and air bubbles from inside the aperture tube. (2) Approximately 30 ml of the above-mentioned aqueous electrolyte solution is placed in a 100 ml flat-bottom glass beaker, and approximately 0.3 ml of a dilution of Contaminon N (a 10% aqueous solution of a pH 7 neutral detergent for cleaning precision measuring instruments, consisting of a nonionic surfactant, an anionic surfactant, and an organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) diluted approximately three times by mass with ion-exchanged water is added as a dispersant. (3) Prepare an ultrasonic disperser "Ultrasonic Dispersion System Tetora150" (manufactured by Nikkaki Bios Co., Ltd.) with an electrical output of 120 W and two built-in oscillators with an oscillation frequency of 50 kHz and a phase difference of 180 degrees. Place approximately 3.3 L of ion-exchanged water in the ultrasonic disperser's water tank, and add approximately 2 mL of Contaminon N to this water tank. (4) Set the beaker (2) in the beaker fixing hole of the ultrasonic disperser, operate the ultrasonic disperser, and adjust the height of the beaker so that the resonance state of the liquid surface of the electrolytic solution in the beaker is maximized. (5) While the electrolyte solution in the beaker in (4) is irradiated with ultrasonic waves, approximately 10 mg of toner is added little by little to the electrolyte solution and dispersed. The ultrasonic dispersion process is then continued for another 60 seconds. During the ultrasonic dispersion, the water temperature in the water tank is appropriately adjusted to be between 10°C and 40°C. (6) Using a pipette, the electrolytic solution (5) in which the toner has been dispersed is dropped into the round-bottom beaker (1) placed in the sample stand, and the measurement concentration is adjusted to about 5%. Then, measurements are continued until the number of measured particles reaches 50,000. (7) The measurement data is analyzed using the dedicated software provided with the device to calculate the weight-average particle size (Dv). Note that when the dedicated software is set to Graph / Volume %, the "Average diameter" on the "Analysis / Volume Statistics (Arithmetic Mean)" screen is the weight-average particle size (Dv).

[0115] <Silica fine particles 29 Calculation method for A and A / B using Si-solid state NMR measurement Parameter A, parameter B, and A / B are calculated using silica particles separated from the toner surface. 29The calculation is performed using Si-solid NMR measurement. Below, we will explain the method for separating silica particles from the toner surface and 29 The Si-solid state NMR measurement method is described.

[0116] (Method for separating silica particles from the toner surface) When silica fine particles separated from the surface of the toner are used as a measurement sample, the silica fine particles are separated from the toner by the following procedure. A concentrated sucrose solution was prepared by adding 160 g of sucrose (Kishida Chemical) to 100 mL of ion-exchanged water and dissolving it in a hot water bath. A centrifuge tube was charged with 31 g of the concentrated sucrose solution and 6 mL of Contaminon N (a 10% by weight aqueous solution of a pH 7 neutral detergent for cleaning precision measuring instruments, consisting of a nonionic surfactant, an anionic surfactant, and an organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) to prepare a dispersion. 1 g of toner was added to the dispersion, and any clumps of toner were broken up using a spatula or similar tool.

[0117] The centrifuge tube is placed in an Iwaki Sangyo KM Shaker (model V.SX) and shaken at 350 strokes per minute for 20 minutes. After shaking, the solution is transferred to a 50 mL glass tube for a swing-out rotor and centrifuged at 3,500 rpm for 30 minutes. After centrifugation, the toner is present in the top layer of the glass tube, and the silica fine particles are present in the aqueous solution in the lower layer. The aqueous solution in the lower layer is collected and centrifuged repeatedly as necessary to separate the particles sufficiently, after which the dispersion is dried and the silica fine particles are collected. Next, the silica particles recovered from the toner 29 Si-solid state NMR measurement is carried out under the measurement conditions shown below.

[0118] ( 29 Si-NMR (solid state) measurement conditions Equipment: BRUKER AVANCE III 500 Probe: 4mm MAS BB / 1H Measurement temperature: room temperature Sample rotation speed: 6kHz Sample: Silica fine particles: 150 mg Measurement nuclear frequency: 99.36MHz Reference material: DSS (external standard: 1.534ppm) Observation width: 29.76kHz Measurement method: DD / MAS, CP / MAS 90° pulse width: 4.00μs, -1dB Contact time: 1.75ms to 10ms Repeat time: 30 s (DD / MASS), 10 s (CP / MAS) Accumulation count: 2048 times LB value: 50Hz

[0119] After the above measurement, the peaks of a plurality of silane components having different substituents and bonding groups are separated into the following M units, D units, T units, and Q units by curve fitting. M unit structure: (Ri)(Rj)(Rk)SiO 1 / 2 Formula (4) D unit structure: (Rg)(Rh)Si(O 1 / 2 )2 formula (5) T unit structure: RmSi(O 1 / 2 )3 formula (6) Q unit structure: Si(O 1 / 2 )4 formula (7)

[0120] In the formulas (4), (5), and (6), Ri, Rj, Rk, Rg, Rh, and Rm represent an alkyl group such as a hydrocarbon group having 1 to 6 carbon atoms, a halogen atom, a hydroxy group, an acetoxy group, a carbinol group, an epoxy group, a carboxy group, a hydrogen atom, or an alkoxy group bonded to a silicon atom.

[0121] After peak separation, the values ​​of parameters A, B, and A / B are calculated by setting the integral value of D units obtained when the integral value of Q units in CP / MAS measurement is set to 100 as A, and the integral value of D units obtained when the integral value of Q units in DD / MAS measurement is set to 100 as B. Here, the method for measuring parameters A, B, and A / B of silica fine particles contained in toner has been described, but raw materials for the silica fine particles may also be measured.

[0122] (Determining whether silica particles have been surface treated with silicone oil) The analytical method for confirming that silica microparticles have been surface-treated with silicone oil is to use a pyrolysis apparatus (Japan Analytical Industry Co., Ltd., JPS-330). When 0.1 mg of sample is heated from 20°C to 500°C, an MS spectrum derived from silicone oil can be obtained. For comparison, silicone oil is also measured in the same way to obtain an MS spectrum. When the two spectra are compared and a high percentage of the MS spectrum derived from silicone oil matches, it can be determined that the silica microparticles have been surface-treated with silicone oil.

[0123] <Calculation of the number average particle diameter Rb of silica fine particle aggregates, the number average particle diameter Ra of primary particles, Rb / Ra, and coefficient of variation> The number-average particle size Rb of silica particle aggregates, the number-average particle size Ra of primary particles, Rb / Ra, coefficient of variation, and other physical properties are measured by sampling silica particles adhering to the toner particle surface. When there are multiple silica particles, the analysis is performed on silica particles with a primary particle size of 50 nm or less among all the silica particles adhering to the toner particle surface.

[0124] (Collection of silica particles from toner) (1) Collection of silica particle samples 0.1 g of toner, 20 ml of ion-exchanged water, and 0.1 ml of Contaminon N (a 10% by mass aqueous solution of a neutral detergent for cleaning precision measuring instruments, pH 7, consisting of a nonionic surfactant, an anionic surfactant, and an organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) are placed in a 30 ml glass vial. The tip of an ultrasonic vibrator UH-50 (manufactured by SMT Corporation, using a titanium alloy tip with a tip diameter of 6 mm) is set at the center of the vial and 5 mm above the bottom of the vial, and the silica microparticles are detached from the surface of the toner particles by ultrasonic dispersion. The output of the ultrasonic dispersion is set to 30 W so as not to change the shape of the aggregates of silica microparticles on the surface of the toner particles. After applying ultrasonic waves for 10 minutes, the mixture is left to stand for 30 minutes, and the supernatant is collected and dropped onto a glass slide. It is then dried overnight. During this process, heat is applied as little as possible, and the mixture is vacuum dried at 30°C or below to obtain a silica microparticle sample for measurement.

[0125] (Measurement of silica particle sample) (2) SEM observation Measurements of silica particle samples are performed using images obtained by backscattered electron observation using a field emission scanning electron microscope S-4800 (Hitachi High-Technologies Corporation). Backscattered electron images tend to provide higher contrast images of silica particle samples than secondary electron images, allowing for accurate measurement of silica particle samples. The observation conditions are as follows: Accelerating voltage: 0.8 kV Emission current: 20 μA Detector: [SE upper (U)], [+BSE (LA100)] Probe current: [Normal] Focus mode: [UHR] WD: [3.0 mm]

[0126] (3) Focus adjustment Drag within the magnification display area on the control panel to set the magnification to 100,000 (100k). Rotate the focus knob [COARSE] on the operation panel to achieve a certain degree of focus, then adjust the aperture alignment. Click [Align] on the control panel to display the alignment dialog, and select [Beam]. Rotate the STIGMA / ALIGNMENT knobs (X, Y) on the operation panel to move the displayed beam to the center of the concentric circles. Next, select [Aperture], and rotate the STIGMA / ALIGNMENT knobs (X, Y) one by one to stop the image movement or minimize its movement. Close the aperture dialog, and use autofocus to adjust the focus. Repeat this operation twice more to adjust the focus.

[0127] FIG. 5 is an example of a schematic diagram of observed silica microparticles. 154 indicates an aggregate of silica microparticles, 155 indicates the maximum Feret diameter, and 156 indicates the minimum Feret diameter. 157 indicates the particle size of the primary particles of the silica microparticles. Then, at least 300 silica microparticles are measured. The number average particle size of the maximum Feret diameter is taken as the number average particle size Rb of the aggregate of silica microparticles. The number average particle size of the particle size of the primary particles is taken as the number average particle size Ra of the primary particles of the silica microparticles. Rb / Ra can be obtained using Rb and Ra calculated in this way. The coefficient of variation (standard deviation / arithmetic mean value) calculated using all the Rb data is the coefficient of variation of the particle size based on the number of aggregates of silica microparticles. Furthermore, the number of aggregates relative to the total number of aggregates and non-aggregates (aggregate number ratio) can be obtained from the number of aggregates relative to the total number of aggregates and non-aggregates. It should be noted that when the observed silica fine particles are not present in the state of primary particles in the above-mentioned SEM observation, they are judged to have formed aggregates.

[0128] (Measurement of moisture content of toner) The moisture content of the toner is measured using a moisture meter (Sartorius Mark 3HP moisture meter). Specifically, 10 g of toner is weighed into an aluminum pan and the moisture meter is heated to 120°C, thereby obtaining the moisture content of the toner. [Example]

[0129] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited thereto. Parts used in the examples are by weight unless otherwise specified.

[0130] <Production example of silica fine particles 1> Fumed silica (silica base; spherical, BET specific surface area: 300 m 2 100 parts of a hydroxybenzoate (1 / g) was placed in a reaction vessel, and the R 1 and R 2 The side chain is a hydroxy group and the side chain is unsubstituted polydimethylsiloxane (kinematic viscosity at 25°C: 50 mm 2 A solution prepared by diluting 20 parts of silica fine particles (silica fine particles / s) with 100 parts of hexane was added, and while continuing to stir, a reaction treatment was first carried out at 300°C for 120 minutes. The obtained silica fine particles were then crushed using a pin-type crusher to obtain silica fine particles 1. The number-average particle size of the primary particles of the obtained silica fine particles 1 was 7 nm. The physical properties of silica fine particles 1 are shown in Table 1.

[0131] [Table 1]

[0132] <Production Examples of Silica Microparticles 2 to 14> In the manufacturing example of silica fine particles 1, treatment condition 1 (R in polydimethylsiloxane) 1 and R 2Silica microparticles 2 to 14 were produced in the same manner as the method for producing silica microparticles 1, except that treatment conditions 1 (type of polydimethylsiloxane, amount of polydimethylsiloxane added) and treatment conditions 2 (type of polydimethylsiloxane, amount of polydimethylsiloxane added) were changed as shown in Table 1. The physical properties of silica microparticles 2 to 14 are shown in Table 1. Here, treatment conditions 2 refer to the process where R in polydimethylsiloxane of formula (B) is added after treatment conditions 1. 1 and R 2 is a methyl group, i.e., polydimethylsiloxane of formula (A) is used, and the conditions for successive treatments in which the amount of polydimethylsiloxane added is changed are shown below.

[0133] <Production example of silica fine particles 15> Untreated dry silica (average primary particle size = 9 nm) was placed in an autoclave equipped with a stirrer and heated to 200°C while being fluidized by stirring. The inside of the reactor was replaced with nitrogen gas, the reactor was sealed, and 25 parts of hexamethyldisilazane per 100 parts of dry silica was sprayed into the interior, and the silica was treated with a silane compound while being fluidized. This reaction was continued for 60 minutes, and then terminated. After completion of the reaction, the autoclave was depressurized and washed with a stream of nitrogen gas to remove excess hexamethyldisilazane and by-products from the hydrophobic silica. Further, while stirring the inside of the reaction vessel, 100 parts of dry silica and 10 parts of dimethyl silicone oil (viscosity = 100 mm 2 After stirring for 30 minutes, the mixture was heated to 300°C with stirring and further stirred for 2 hours, then removed and crushed to obtain silica microparticles 15. The physical properties of silica microparticles 15 are shown in Table 1.

[0134] <Manufacturing example of silica fine particles 16> Oxygen gas was supplied to the burner, and the ignition burner was ignited. Then, hydrogen gas was supplied to the burner to form a flame, and silicon tetrachloride, the raw material, was added to the flame and gasified to obtain silica microparticles. The specific method was prepared by referring to the descriptions in JP-A-2002-003213 and JP-A-6478664. Specifically, the combustion-supporting gas supply pipe was opened to supply oxygen gas to the burner, and the ignition burner was ignited. After that, the combustible gas supply pipe was opened to supply hydrogen gas to the burner to form a flame. Silicon tetrachloride was gasified in an evaporator and supplied to the burner, and a flame hydrolysis reaction was carried out to produce silicon tetrachloride. The resulting silica powder was collected in a bag filter of the collection device to produce silica fine particles. The specific gas injection conditions were silicon tetrachloride injection at 200 kg / hr, hydrogen gas injection at 60 Nm 3 / hr, oxygen gas injection 60Nm 3 The obtained silica fine particles had a number-average primary particle diameter of 30 nm and a BET specific surface area of ​​50 m 2 / g. 10 parts of hexamethyldisilazane was added as a surface treatment agent to 100 parts of the obtained silica fine particles to perform hydrophobic treatment, thereby obtaining silica fine particles 16. The physical properties of the obtained silica fine particles 16 are shown in Table 1.

[0135] <Production example of silica fine particles 17> 100 parts of fumed silica (number average particle size of primary particles of silica raw material is 14 nm) was placed in a reaction vessel, and methylhydrogenpolysiloxane (kinematic viscosity at 25°C: 20 mm) was added with stirring under nitrogen purging. 2 A solution prepared by diluting 20 parts of silica fine particles (silica fine particles / s) with 100 parts of hexane was added, and treatment was carried out with continuous stirring. The obtained silica fine particles were then crushed using a pin-type crusher to obtain silica fine particles 17. The number-average particle diameter of the primary particles of the obtained silica fine particles 17 was 14 nm. The physical properties of silica fine particles 17 are shown in Table 1.

[0136] <Magnetic material manufacturing example> (Magnetic material 1) An aqueous solution containing ferrous hydroxide was prepared by mixing 1.00 to 1.10 equivalents of caustic soda solution relative to elemental iron, P2O5 in an amount equivalent to 0.12 mass% of phosphorus relative to elemental iron, and SiO2 in an amount equivalent to 0.60 mass% of silicon relative to elemental iron into an aqueous solution of ferrous sulfate. The pH of the aqueous solution was adjusted to 8.0, and an oxidation reaction was carried out at 85°C while blowing in air to prepare a slurry containing seed crystals. Next, an aqueous solution of ferrous sulfate was added to this slurry in an amount of 0.90 to 1.20 equivalents relative to the initial alkalinity (sodium content of caustic soda). The pH of the slurry was maintained at 7.6, and air was blown in to promote oxidation, yielding a slurry containing magnetic iron oxide. After filtration and washing, the aqueous slurry was temporarily removed. A small amount of the aqueous sample was then taken and its water content was measured. Next, this hydrous sample was placed in another aqueous medium without drying, and redispersed using a pin mill while stirring and circulating the slurry. The pH of the redispersion was adjusted to approximately 4.8. Then, while stirring, 1.7 parts of n-hexyltrimethoxysilane coupling agent was added per 100 parts of magnetic iron oxide (the amount of magnetic iron oxide was calculated by subtracting the water content from the hydrous sample) to perform hydrolysis. After thorough stirring, the pH of the dispersion was adjusted to 8.6, and surface treatment was performed. The resulting hydrophobic magnetic material was filtered using a filter press, washed with a large amount of water, and then dried at 100°C for 15 minutes and then at 90°C for 30 minutes. The resulting particles were then crushed to obtain Magnetic Material 1 with a volume average particle size of 0.23 μm.

[0137] (Production Example of Amorphous Polyester Resin 1) The molar ratio of the polyester monomers is as follows: BPA-PO / BPA-EO / TPA / TMA=50 / 50 / 70 / 12 Here, BPA-PO represents a 2.2 mole propylene oxide adduct of bisphenol A, BPA-EO represents a 2.2 mole ethylene oxide adduct of bisphenol A, TPA represents terephthalic acid, and TMA represents trimellitic anhydride.

[0138] Of the raw material monomers shown above, raw material monomers other than TMA and 0.1% by mass of tetrabutyl titanate as a catalyst were placed in a flask equipped with a dehydration tube, a stirring blade, a nitrogen inlet tube, etc., and condensation polymerization was carried out at 220°C for 10 hours. TMA was then added, and the mixture was reacted at 210°C until the desired acid value was reached, thereby obtaining amorphous polyester resin 1 (glass transition temperature Tg of 64°C, acid value of 17 mgKOH / g, peak molecular weight of 6,300).

[0139] <Toner Particle Production Example 1> 450 parts of 0.1M Na3PO4 aqueous solution was added to 720 parts of ion-exchanged water and heated to 60°C, and then 67.7 parts of 1.0M CaCl2 aqueous solution was added to obtain an aqueous medium containing a dispersion stabilizer. Styrene: 78.0 parts n-Butyl acrylate: 22.0 parts Divinylbenzene: 0.6 parts Monoazo dye iron complex (T-77: Hodogaya Chemical Co., Ltd.): 2.0 parts ·Magnetic material 1: 90.0 parts Amorphous polyester resin 1: 3.0 parts

[0140] The above formulation was uniformly dispersed and mixed using an attritor (Mitsui Miike Chemical Engineering Co., Ltd.) to obtain a polymerizable monomer composition. The obtained polymerizable monomer composition was heated to 60°C, and 15.0 parts of Fischer-Tropsch wax (melting point: 74°C, number average molecular weight Mn: 500) was added and mixed to dissolve it, and then 7.0 parts of dilauroyl peroxide was dissolved as a polymerization initiator to obtain a toner composition. The toner composition was added to the aqueous medium and granulated by stirring at 12,500 rpm for 12 minutes in a TK homomixer (Tokushu Kika Kogyo Co., Ltd.) at 60°C under a N2 atmosphere, followed by reaction at 74°C for 6 hours while stirring with a paddle stirring blade. After the reaction was completed, the suspension was cooled, washed with hydrochloric acid, and then filtered. The suspension was then dried at 40°C for 66 hours to obtain toner particles 1. The weight average particle size Dv of the obtained toner particles 1 was 7.2 μm. The moisture content of the toner particles 1 was 0.15% by mass.

[0141] (Production example of toner particles 2) Toner particles 2 were obtained in the same manner as in the production example of toner particles 1, except that the drying conditions were changed to 40°C and 40 hours. The weight average particle size Dv of the obtained toner particles 2 was 7.2 μm. The moisture content of toner particles 2 was 0.40 mass%.

[0142] (Production Example of Toner Particle 3) Toner particles 3 were obtained in the same manner as in the production example of toner particles 1, except that the drying conditions were changed to 40°C for 30 hours. The weight average particle size Dv of the obtained toner particles 3 was 7.2 μm. The moisture content of toner particles 3 was 0.50 mass%.

[0143] <Toner Production Example 1> The toner particles 1 obtained in Toner Particle Production Example 1 were subjected to an external addition mixing treatment using the device shown in FIG. In this embodiment, in the apparatus shown in FIG. 3, the diameter of the inner periphery of the main casing 1 is 130 mm, and the volume of the processing space 9 is 2.0×10 -3 m 3 The apparatus used was one in which the rated power of the drive unit 8 was 5.5 kW, and the shape of the agitator 3 was that shown in Fig. 4. The overlap width d of the agitator 3a and agitator 3b in Fig. 4 was set to 0.25D relative to the maximum width D of the agitator 3, and the clearance between the agitator 3 and the inner periphery of the main casing 1 was set to 3.0 mm.

[0144] With the above-described device configuration, 100 parts of toner particles 1 and 0.40 parts of silica fine particles 1 were added to the device shown in Figure 3. After adding the toner particles and silica fine particles, pre-mixing was performed to uniformly mix the toner particles and silica fine particles. The pre-mixing conditions were a power of 0.25 W / g for the drive unit 8 and a processing time of 3 minutes. After the pre-mixing, an external addition mixing process was carried out. The external addition mixing process conditions were that the peripheral speed of the outermost end of the stirring member 3 was adjusted so that the power of the drive unit 8 was constant at 0.40 W / g, and the processing time was 5 minutes.

[0145] After the external additive mixing process, coarse particles were removed using a circular vibrating sieve equipped with a screen with a diameter of 500 mm and openings of 75 μm to obtain Toner 1. Analysis of Toner 1 revealed that the parameter A was 158, Rb was 25 nm, and the coefficient of variation was 2.25. The moisture content of Toner 1 was 0.15% by mass. The external additive conditions and physical properties of Toner 1 are shown in Table 2.

[0146] <Toner Production Examples 2 to 17 and Comparative Toner Production Examples 2 to 4, 8> In the production example of Toner 1, toner particles, silica fine particles, and external addition conditions were changed as shown in Table 3 to obtain Toners 2 to 17 and Comparative Toners 2 to 4 and 8. The physical properties of the obtained toners are shown in Table 2.

[0147] <Comparative Toner Production Example 1> 100 parts of toner particles 3 and 0.5 parts of silica fine particles 8 were dry mixed for 10 minutes at 3400 rpm using an FM10C (manufactured by Nippon Coke and Engineering Co., Ltd.) to obtain comparative toner 1. The physical properties of the obtained comparative toner 1 are shown in Table 2.

[0148] <Production example of comparative toner 5> The toner particles 3 were subjected to an external addition mixing process using the device shown in FIG. Specifically, 100 parts of toner particles 3 and 0.40 parts of silica microparticles 15 were charged into the device shown in FIG. 3. Subsequently, pre-mixing was carried out. The pre-mixing conditions were a power of 0.10 W / g for the drive unit 8 and a processing time of 1 minute. After pre-mixing was completed, an external addition mixing process was carried out. The external addition mixing process conditions were a power of 0.60 W / g for the drive unit 8 and a processing time of 3 minutes. Then, 0.10 parts of silica fine particles 15 were added (a total of 0.50 parts per 100 parts of toner particles), the power of drive unit 8 was adjusted to a constant 0.60 W / g, and processing was continued for another 2 minutes. After the external addition and mixing processing, coarse particles were removed using a circular vibrating sieve equipped with a screen with a diameter of 500 mm and openings of 75 μm, and comparative toner 5 was obtained. The physical properties of comparative toner 5 are shown in Table 2.

[0149] <Production Example of Comparative Toner 6> 100 parts of toner particles 3 were dry-mixed with 0.5 parts of silica microparticles 16 and 1.0 part of hydrophobic silica particles RY300 (manufactured by Nippon Aerosil Co., Ltd., silica microparticles treated with dimethyl silicone oil with a number-average particle size of 8 nm for primary particles) in an FM10C (manufactured by Nippon Coke and Engineering Co., Ltd.) at 3400 rpm for 10 minutes to obtain comparative toner 6. The physical properties of the obtained comparative toner 6 are shown in Table 2.

[0150] <Production Example of Comparative Toner 7> To 100 parts of toner particles 3, 2.0 parts of silica microparticles 17 and 1.0 part of NX90 (manufactured by Nippon Aerosil Co., Ltd., primary particle number average particle size 12 nm, treating agent hexamethyldisilazane) were added. The external additive treatment device used was a 20-liter FM20C (manufactured by Nippon Coke & Engineering Co., Ltd.), and the treatment was carried out at a temperature of 30°C, with a stirring blade peripheral speed of 50 m / s, and a treatment time of 10 minutes. After treatment, coarse particles were removed using a sieve with 45 μm openings, to obtain comparative toner 7. The physical properties of the obtained comparative toner 7 are shown in Table 2.

[0151] [Table 2] In the table, A represents parameter A and B represents parameter B. The coefficient of variation is the coefficient of variation of particle size based on the number of aggregates.

[0152] Example 1 (Durability rating) The following evaluations were carried out using Toner 1. The evaluations were carried out in an environment of 32.5°C and 80% RH. The fixing media was Canon A4 size OceRedLabel paper (basis weight 80 g / m 2 The image forming device used was a commercially available LBP-3100 (Canon), modified to increase the printing speed from 16 sheets per minute to 40 sheets per minute.

[0153] A horizontal line image with a coverage rate of 1.5% was printed on 8,000 sheets in intermittent mode. After printing another 8,000 sheets, the toner cartridge was removed and shook 30 times, after which the image was output again. Shaking the toner cartridge causes the deteriorated toner on the developing roller to mix with the relatively undeteriorated toner in the toner cartridge container, which tends to broaden the charge distribution of the toner on the developing roller. For this reason, the evaluation was very strict regarding fog and uneven fog. The following evaluations were performed, and good results were obtained. The evaluation results are shown in Table 3.

[0154] <Image density> The image density was measured by forming a solid black image portion and measuring the density of the solid black image with a Macbeth reflection densitometer (manufactured by Macbeth Co., Ltd.) The higher the image density, the better the image quality.

[0155] <Focus> A solid white image was printed, and its reflectance was measured using a Tokyo Denshoku Reflectometer Model TC-6DS. The reflectance of the transfer paper (standard paper) before the solid white image was formed was also measured in the same manner. A green filter was used. Fog was calculated from the reflectance before and after the solid white image was printed using the following formula: Fog (reflectance) (%) = Reflectance of standard paper (%) - Reflectance of solid white image sample (%) The lower the fog (reflectance), the better the result. The average value of the fog values ​​when one evaluation image is evaluated on a 10-point scale is taken as the average fog, and the maximum value is taken as the maximum fog. The maximum fog is particularly large because unevenness in the toner charging property causes the fog to be output as an uneven image.

[0156] <Examples 2 to 17> Toners 2 to 17 were evaluated in the same manner as in Example 1, and good results were obtained. The evaluation results are shown in Table 3.

[0157] [Table 3] In the table, "solid" indicates the image density of a solid black image.

[0158] <Comparative Examples 1 to 8> Comparative toners 1 to 8 were used and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 4. [Table 4] [Explanation of symbols]

[0159] 1: main body casing, 2: rotor, 3, 3a, 3b: agitator, 4: jacket, 5: raw material inlet, 6: product outlet, 7: central shaft, 8: drive unit, 9: treatment space, 10: rotor end side, 11: rotation direction, 12: return direction, 13: feed direction, 16: inner piece for raw material inlet, 17: inner piece for product outlet, d: gap indicating overlapping portion of agitator, D: width of agitator 100: electrostatic latent image carrier (photosensitive member), 102: toner carrier, 103: developing blade, 114: transfer member (transfer charging roller), 116: cleaner container, 117: charging member (charging roller), 121: laser generating device (latent image forming means, exposure device), 123: laser, 124: pickup roller, 125: conveying belt, 126: fixing unit, 140: developing unit, 141: stirring member 151: treatment agent for silica fine particles, 152: silica fine particles, 153: silica fine particles in an aggregated state, 154: primary particles of silica fine particles in an aggregate of silica fine particles, 155: maximum Feret diameter of aggregate of silica fine particles, 156: minimum Feret diameter of aggregate of silica fine particles, 157: particle size of primary particles of silica fine particles

Claims

1. A toner containing toner particles and an external additive on the surface of the toner particles, the external additive contains silica fine particles surface-treated with silicone oil, The silica fine particles surface-treated with the silicone oil contain aggregates and non-aggregates, the proportion of the number of aggregates of the silica fine particles is 40% or more based on the total number of aggregates of the silica fine particles and the number of non-aggregates of the silica fine particles; a total content of the aggregates of the silica fine particles and the non-aggregates of the silica fine particles is 0.10 parts by mass or more and 4.00 parts by mass or less relative to 100 parts by mass of the toner particles, the number-average particle size Rb of the aggregates of the silica fine particles is 12 nm or more and 80 nm or less; The silica fine particles ２９ In Si-solid state NMR, when the integral value of the D unit obtained when the integral value of the Q unit in the CP / MAS measurement is set to 100 is defined as A, A is 120 or more and 300 or less, the coefficient of variation of the particle size based on the number of aggregates of the silica fine particles is 1.00 or more and 3.00 or less; The silicone oil is a modified silicone oil represented by the following formula (B): A toner characterized by: (In formula (B), R １ is a carbinol group, a hydroxy group, an epoxy group, a carboxy group, an alkyl group, or a hydrogen atom, R ２ is a carbinol group, a hydroxy group, an epoxy group, or a carboxy group. m is the average number of repeating units, and the modified silicone oil represented by formula (B) has a kinematic viscosity of 20 mm at 25°C. ２ / s to 1000mm ２ / s.)

2. The number average particle size Ra of the primary particles of the silica fine particles is 5 nm or more and 30 nm or less.

2. The toner according to claim 1.

3. When the number average particle diameter of the primary particles of the silica fine particles is Ra, The Ra and the Rb satisfy the following formula (1): The toner according to claim 1 or 2. 2.5≦Rb / Ra≦5.0 (1)

4. The silica fine particles ２９ The toner according to any one of claims 1 to 3, wherein, in Si-solid state NMR, when an integral value of D units obtained by setting an integral value of Q units in DD / MAS measurement to 100 is defined as B, A and B satisfy the following formula (2): 3.0≦A / B≦6.0...(2)

5. 5. The toner according to claim 1, wherein the water content of the toner is 0.40% by mass or less.

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