toner

Abstract

To provide a toner that has excellent developability and can provide high image density even if it is left standing for a long period in a high temperature and high humidity environment.SOLUTION: A toner contains a toner particle containing a magnetic substance and silica fine particles on the surface of the toner particle. In measurement in time-of-flight secondary ion mass spectroscopy of the silica fine particles, fragment ions corresponding to the D-unit structure are observed. When the silica fine particles are dispersed in a mixed solution of ethanol and a NaCl solution and a titration operation using sodium hydroxide is performed, a titration amount falls within a specific range. In chemical shift obtained by solid 29Si-NMR of the silica fine particles, when the area of a peak where a peak top is present within a range from -25 to -15 ppm is defined as D, and the area of a peak where a peak top is present within a range exceeding -19 ppm and -17 ppm or less is defined as D1, D and D1 are present at a specific ratio. The magnetic substance is present on the surface of the toner particle.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This disclosure relates to toner used in image forming methods such as electrophotography. [Background technology]

[0002] In recent years, image forming devices such as photocopiers and printers have seen increasing diversification of their intended use and operating environments, as well as a growing demand for longer lifespans and smaller sizes. To achieve longer lifespans and smaller sizes, it is necessary to reduce toner consumption. Reducing toner consumption enables long-term image formation with smaller toner volumes. Improving toner transferability is crucial for reducing toner consumption.

[0003] Toner particles containing magnetic material, such as those made from kneaded and ground toner particles, have components with low electrical resistance on their surface, which facilitates the relaxation and homogenization of charge. Therefore, even when subjected to a large transfer bias, excessive and irregular charging is suppressed, which reduces electrostatic adhesion to the photoreceptor and allows for good transferability. On the other hand, toners containing toner particles with magnetic material on their surface tend to have reduced developability and decreased image density when left in high-temperature and high-humidity environments for extended periods. In contrast, a technique has been disclosed for improving the image density of compounded and ground toner containing magnetic materials by using silica particles surface-treated with a specific amount or more of cyclic siloxane as an external additive (Patent Document 1). Furthermore, a technology has been disclosed concerning surface-coated silica particles that retain a certain amount of free silicone oil by being coated with two or more types of silicone oils as external additives (Patent Document 2). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2016-167029 [Patent Document 2] Japanese Patent Publication No. 2007-176747 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, it has become clear that the silica particles used in Patent Documents 1 and 2 do not have appropriate processing methods or amounts for cyclic siloxanes and silicone oils, and that the effect of improving developability when such silica particles are added to toner is low. In other words, it has been found that there is still room for improvement in terms of improving developability in high-temperature and high-humidity environments for toners containing toner particles with magnetic material on their surface. This disclosure provides a toner that has excellent developability even when containing toner particles with magnetic material on their surface, and that can obtain high image density even when left in a high-temperature, high-humidity environment for a long period of time. [Means for solving the problem]

[0006] This disclosure relates to a toner containing magnetic material toner particles and silica fine particles on the surface of said toner particles, In time-of-flight secondary ion mass spectrometry measurements of the silica nanoparticles, fragment ions corresponding to the structure shown in equation (1) below were observed. [ka] In equation (1), n ​​represents an integer of 1 or greater, When 2.00 g of the silica fine particles were dispersed in a mixture of 25.0 g of ethanol and 75.0 g of a 20% by mass NaCl aqueous solution, and a titration was performed using sodium hydroxide, Sn, defined as Sn = {(ab) × c × NA} / (d × e), satisfies equation (2) below. 0.05 ≤ Sn ≤ 0.20 ···(2) In formula (2), a is the amount of NaOH titration (L) required to adjust the mixture containing the dispersed silica particles to pH 9.0. b is the amount of NaOH titration (L) required to adjust a mixture of 25.0 g of ethanol and 75.0 g of 20% by mass NaCl aqueous solution to pH 9.0. c is the concentration (mol / L) of the NaOH solution used in the titration. NA is Avogadro's number, d is the mass (g) of the silica fine particles, e is the BET specific surface area (nm) of the silica nanoparticles. 2 / g) is Solid silica fine particles 29 In the chemical shift obtained by the Si-NMR DD / MAS method, D is the area of ​​the peaks with peak tops in the range of -25 to -15 ppm, S is the sum of the areas of the M, D, T, and Q unit peaks in the range of -140 to 100 ppm, and B is the specific surface area of ​​the silica nanoparticles. 2 When we set it to / g, The ratio of (D / S) to B, (D / S) / B, is 5.7 × 10 -4 ~56×10 -4 And, The (D / S) / B value measured after washing the silica microparticles with chloroform was 1.7 × 10⁻⁶. -4 ~56×10 -4 And, In the chemical shift, when D1 is defined as the area of ​​the peaks where the peak top is located in the range between -19 ppm and -17 ppm, the ratio of D1 to D (D1 / D) is between 0.10 and 0.30. This invention relates to a toner in which the magnetic material is present on the surface of the toner particles. [Effects of the Invention]

[0007] Even with toner particles containing magnetic material on their surface, it is possible to provide a toner that exhibits excellent developability and can obtain high image density even when left in a high-temperature, high-humidity environment for a long period of time. [Modes for carrying out the invention]

[0008] In this disclosure, descriptions of numerical ranges such as "XX or more and YY or less" or "XX to YY" mean a numerical range that includes the lower and upper limits, unless otherwise specified. When numerical ranges are described in steps, the upper and lower limits of each numerical range can be combined in any way. Furthermore, a monomer unit refers to the reacted form of monomer material in a polymer.

[0009] As mentioned above, toners containing toner particles with magnetic material on their surface have excellent transfer properties. On the other hand, when left in a high-temperature, high-humidity environment, the developability tends to deteriorate. This is thought to be because the presence of a magnetic material with low electrical resistance on the surface of the toner particles makes it easier for the charge of the toner to leak out. When such toner is left in a high-temperature, high-humidity environment where moisture has a significant impact, excessive charge leakage occurs. As a result, it is presumed that there is insufficient charge necessary for development. Therefore, the inventors investigated a toner that contains toner particles with magnetic material on its surface while maintaining high charge retention. After diligent research, they found that the aforementioned effects could be obtained by designing the silica nanoparticles to be combined with the toner as follows.

[0010] The silica nanoparticles described herein are explained below. First, the inventors focused on the surface of silica nanoparticles. The surface of silica nanoparticles is hydrophilic because it contains hydroxyl groups (OH groups), i.e., silanol groups, which are included in the silanol structure. Therefore, the surface of silica nanoparticles easily adsorbs moisture from the air. For this reason, especially in high temperature and high humidity environments, the electrical resistance of silica decreases due to moisture adsorption, which accelerates the decrease in the charge retention of toner containing toner particles with magnetic material on their surface. However, simply increasing the amount of surface treatment applied to the silica nanoparticle substrate to reduce the surface silanol groups of the silica nanoparticles does not allow for sufficient control of the silanol content, and no improvement in charge retention under high temperature and high humidity conditions is observed. Furthermore, the fluidity of the toner decreases, resulting in reduced charge build-up and even problems such as fusion to internal components of the toner cartridge. To obtain high image density when left for extended periods in high-temperature, high-humidity environments, it is considered necessary to have both high charge retention and high charge rise time. Therefore, these characteristics must be achieved simultaneously.

[0011] The inventors diligently investigated silica nanoparticles that can improve charge retention and ensure charge rise in toners containing toner particles with magnetic material on their surface. As a result, they found that the following toners are effective.

[0012] In other words, this disclosure relates to a toner containing magnetic material toner particles and silica fine particles on the surface of said toner particles, In time-of-flight secondary ion mass spectrometry measurements of the silica nanoparticles, fragment ions corresponding to the structure shown in equation (1) below were observed. [ka] In equation (1), n ​​represents an integer of 1 or greater, When 2.00 g of the silica fine particles were dispersed in a mixture of 25.0 g of ethanol and 75.0 g of a 20% by mass NaCl aqueous solution, and a titration was performed using sodium hydroxide, Sn, defined as Sn = {(ab) × c × NA} / (d × e), satisfies equation (2) below. 0.05 ≤ Sn ≤ 0.20 ···(2) In formula (2), a is the NaOH required to adjust the mixture containing the dispersed silica particles to pH 9.0. The titration volume is (L), b is the amount of NaOH titration (L) required to adjust a mixture of 25.0 g of ethanol and 75.0 g of 20% by mass NaCl aqueous solution to pH 9.0. c is the concentration (mol / L) of the NaOH solution used in the titration. NA is Avogadro's number, d is the mass (g) of the silica fine particles, e is the BET specific surface area (nm) of the silica nanoparticles. 2 / g), and the solid of the silica fine particles 29 In the chemical shift obtained by the Si-NMR DD / MAS method, the area of the peak with the peak top in the range of -25 to -15 ppm is defined as D, and the sum of the areas of the peaks of the M unit, D unit, T unit, and Q unit existing in the range of -140 to 100 ppm is defined as S. When the specific surface area of the silica fine particles is B (m 2 / g), the value of the ratio (D / S) / B of (D / S) to B is 5.7×10 -4 ~56×10 -4 and the (D / S) / B measured after washing the silica fine particles with chloroform is 1.7×10 -4 ~56×10 -4 and In the chemical shift, when the area of the peak with the peak top in the range exceeding -19 ppm and not exceeding -17 ppm is defined as D1, the value of the ratio (D1 / D) of D1 to D is 0.10 to 0.30, It relates to a toner in which the magnetic substance exists on the surface of the toner particles.

[0013] The reason why excellent charge retention can be obtained even in a toner containing toner particles having a magnetic substance on the surface by controlling the surface treatment state (formula (2), (D / S) / B, and D1 / D) of the silica fine particles will be explained.

[0014] In the measurement of the silica fine particles by time-of-flight secondary ion mass spectrometry TOF-SIMS, it is necessary to observe the fragment ion corresponding to the structure represented by formula (1). Observing the fragment ion represented by formula (1) indicates that the silica fine particles are surface-treated with a surface treatment agent having a polydimethylsiloxane structure. Polydimethylsiloxane is hydrophobic, and surface treatment with a treatment agent having a polydimethylsiloxane structure can prevent moisture adsorption of the silica fine particles to the toner in a high-temperature and high-humidity environment.

Chemical formula

[0015] (In formula (1), n ​​is an integer of 1 or greater (preferably between 1 and 500, more preferably between 1 and 200, even more preferably between 1 and 100, and even more preferably between 1 and 80).) TOF-SIMS is a method for analyzing the surface composition of a sample by irradiating the sample with ions and analyzing the mass of secondary ions emitted from the sample. Since secondary ions are emitted from a region several nanometers deep from the sample surface, it is possible to analyze the structure near the surface of silica nanoparticles. The mass spectrum of secondary ions obtained by the measurement is a fragment ion that reflects the molecular structure of the surface treatment agent of the silica nanoparticles.

[0016] In TOF-SIMS measurements, fragment ions corresponding to the structure shown in formula (1) are observed in silica nanoparticles. In this disclosure, the structural unit having this structure is called D unit This is defined as a D unit. If D-unit fragment ions are observed by TOF-SIMS, it means that the silica nanoparticles have been surface-treated with a surface treatment agent containing D units.

[0017] When silica nanoparticles are dispersed in a solvent and titrated with sodium hydroxide, the amount of sodium hydroxide required to adjust to the target pH corresponds to the amount of silanol groups on the silica substrate surface and in the silica surface treatment structure. That is, the amount of Si-OH groups is the value Sn(groups / nm) which can be determined from the amount of sodium hydroxide titrated. 2 This can be evaluated by the following: This is because the Si-OH groups in the silica nanoparticle substrate and the Si-OH groups derived from the surface treatment agent undergo a neutralization reaction with sodium hydroxide. Furthermore, since silanol groups are polar, the electrostatic charge of silica nanoparticles is thought to be controlled by the silanol group content. If the silanol group content is low, the rate at which the electrostatic charge is generated decreases. Conversely, if the silanol group content is excessive, the electrostatic charge retention tends to decrease. Among the silanol groups, the silanol groups on the surface of the silica nanoparticle substrate tend to adsorb moisture, and are therefore thought to contribute particularly greatly to the decrease in electrostatic charge retention.

[0018] Specifically, when 2.00 g of silica fine particles were dispersed in a mixture of 25.0 g of ethanol and 75.0 g of a 20% by mass NaCl aqueous solution and titrated using sodium hydroxide, The Sn defined as Sn = {(ab) × c × NA} / (d × e) must satisfy equation (2) below. 0.05 ≤ Sn ≤ 0.20 ···(2) In formula (2), a is the amount of NaOH titration (L) required to adjust the above mixture containing dispersed silica nanoparticles to pH 9.0. b is the amount of NaOH titration (L) required to adjust a mixture of 25.0 g of ethanol and 75.0 g of 20% by mass NaCl aqueous solution to pH 9.0. c is the concentration (mol / L) of the NaOH solution used in the titration. NA is Avogadro's number, d is the mass (g) of the silica nanoparticles. e is the BET specific surface area (nm) of the silica nanoparticles. 2 It is / g).

[0019] The fact that Sn satisfies formula (2) indicates that the amount of silanol groups on the surface of the silica nanoparticle substrate and in the surface treatment structure of the silica nanoparticles is appropriate. This improves the charge retention and charge rise of the toner. Sn is preferably 0.05 to 0.25, more preferably 0.08 to 0.19, and even more preferably 0.10 to 0.18. The amount of Sn can be increased by treating the silica nanoparticle substrate under conditions where the reaction of the surface treatment agent does not proceed, so that silanol groups remain on the surface of the silica nanoparticle substrate, or by adding only a small amount of the treatment agent so as not to completely cover the surface of the silica nanoparticle substrate. On the other hand, the amount of Sn can be decreased by reducing the silanol groups on the surface of the silica nanoparticles through surface treatment, or by treating them with a surface treatment agent that does not contain silanol groups. In addition, extending the reaction time or raising the temperature during surface treatment is also effective.

[0020] Furthermore, to control the Si-OR group, it is necessary to control the surface treatment state of the silica nanoparticles ((D / S) / B, D1 / D). The surface treatment state of the silica nanoparticles is solid. 29 Si-NMR It is calculated using the DD / MAS method. In the DD / MAS measurement method, all Si atoms in the sample are observed, so quantitative information about the chemical bonding state of Si atoms in silica nanoparticles can be obtained.

[0021] Generally, solid 29 In Si-NMR, four types of P-units are used for Si atoms in a solid sample: M-unit (Equation (4)), D-unit (Equation (5)), T-unit (Equation (6)), and Q-unit (Equation (7)). It is possible to observe Ku. M unit: (R i )(R j )(R k )SiO 1 / 2 Formula (4) D unit: (R g )(R h )Si(O 1 / 2 )2 formula (5) T unit: R m si(O 1 / 2 )3 formula (6) Q unit: Si(O) 1 / 2 )4 formula (7) R in equations (4), (5), and (6) i , R j , R k , R g , R h , R m This refers to alkyl groups such as hydrocarbon groups having 1 to 6 carbon atoms, halogen atoms, hydroxyl groups, acetoxy groups, or alkoxy groups that are bonded to silicon.

[0022] When silica nanoparticles are measured using DD / MAS, the Q unit represents a peak corresponding to the Si atoms in the silica nanoparticle substrate before surface treatment. In this disclosure, when silica nanoparticles are surface-treated with a surface treatment agent such as silicone oil, the portion derived from the surface treatment agent is also referred to as silica nanoparticles. The silica nanoparticles before surface treatment are also referred to as the silica nanoparticle substrate. The M, D, and T units represent peaks corresponding to the structure of the surface treatment agent for silica nanoparticles, as expressed by formulas (4) to (6) above. All are solids 29 Identification is possible by the chemical shift values ​​of the Si-NMR spectrum. Q units appear in the chemical shift range of -130 to -85 ppm, T units in the range of -65 to -51 ppm, D units in the range of -25 to -15 ppm, and M units in the range of 10 to 25 ppm, and each can be quantified by its integral value. The respective peak integral values ​​are denoted as Q, T, D, and M, and the sum of these integral values ​​is denoted as S.

[0023] Solid silica nanoparticles 29 In the chemical shift obtained by the Si-NMR DD / MAS method, D is the area of ​​the peaks with peak tops in the range of -25 to -15 ppm, and S is the sum of the areas of the M, D, T, and Q unit peaks in the range of -140 to 100 ppm. At this time, the BET specific surface area of ​​the silica nanoparticles after surface treatment is B(m²). 2 If we assume ( / g), then (D / S) / B is 5.7 × 10 -4 ~56×10 -4 (5.6 × 10 -3 ) The parameter (D / S) / B represents the amount of Si atoms per unit surface area that constitutes the D unit relative to the total Si atomic amount of the silica nanoparticles. Here, in TOF-SIMS, the fragment shown in equation (1) above is observed, and the solid 29 In Si-NMR measurements, silica nanoparticles exhibiting peaks in the D unit indicate that they have been surface-treated with a compound containing a dimethylsiloxane structure.

[0024] In other words, the parameter (D / S) / B represents the amount of dimethylsiloxane on the surface of silica nanoparticles per unit surface area. A smaller (D / S) / B value indicates less dimethylsiloxane on the surface of the silica nanoparticles, meaning it does not inhibit fluidity as an external additive. However, because silanol groups tend to remain on the silica substrate surface, the effects of moisture in high-temperature, high-humidity environments cannot be suppressed, resulting in only a small improvement in charge retention. Conversely, a larger (D / S) / B ratio results in a greater amount of dimethylsiloxane on the surface of the silica nanoparticles. However, an excess of D units inhibits fluidity as an external additive, which also tends to reduce electrostatic properties. Furthermore, if the dimethylsiloxane treatment is uneven, silanol groups remain on the surface of the silica nanoparticle substrate, which can lead to reduced electrostatic properties, especially in high-temperature and high-humidity environments when printing a large number of sheets.

[0025] Therefore, (D / S) / B is 5.7 × 10 -4 ~56×10 -4 It is necessary that (D / S) / B is 5.7 × 10 -4 If the value falls below this level, the dimethylsiloxane treatment is insufficient, and the toner's charge retention will significantly decrease in high-temperature, high-humidity environments. Also, if (D / S) / B is 56 × 10 -4 If this value is exceeded, the amount of dimethylsiloxane becomes excessive, and the fluidity of the toner decreases significantly. (D / S) / B is 5.7 × 10 -4 ~49×10 -4 Preferably, 7.1 × 10 -4 ~49×10 -4 It is preferable that it be so. (D / S) / B can be increased by increasing the amount of surface treatment agent used when treating the silica nanoparticle substrate, or by using a surface treatment agent that contains a large amount of components having a polydimethylsiloxane structure. On the other hand, (D / S) / B can be decreased by decreasing the amount of surface treatment agent used when treating the silica nanoparticle substrate, or by using a surface treatment agent that does not contain a large amount of components having a polydimethylsiloxane structure.

[0026] Therefore, the silica nanoparticles are surface-treated with an appropriate amount of D units, and the amount of silanol on the surface of the silica nanoparticles is controlled within an appropriate range. Furthermore, the (D / S) / B measured after washing the silica microparticles with chloroform was 1.7 × 10⁻⁶. -4 ~56×10 -4 This is necessary. The cleaning operation removes the surface treatment agent that has been physically adsorbed, leaving behind the chemically bonded surface treatment agent. Therefore, (D / S) / B after cleaning indicates the amount of chemically bonded D units. (D / S) / B is 1.7 × 10 -4 If the value is less than 56 × 10, the amount of surface treatment agent adhering to the surface of the silica microparticles is insufficient. As a result, the surface treatment agent on the silica microparticles may peel off during long-term use, making it impossible to prevent moisture adsorption in high-temperature and high-humidity environments. -4 Larger sizes tend to reduce toner fluidity and decrease its electrostatic properties. The (D / S) / B ratio after washing silica microparticles with chloroform is preferably 2.5 × 10⁻⁶. -4 ~45×10 -4 And more preferably 3.5 × 10 -4 ~40×10 -4 That is the case.

[0027] Here, we define D1 as the polar group at the end of the structure derived from the surface treatment agent of silica nanoparticles. D1 is a solid, which will be described later. 29 In the chemical shift obtained by Si-NMR, this corresponds to a peak whose peak top is located in the range between -19 ppm and -17 ppm. In silica nanoparticles treated with D units, D1 represents the polar group at the end of the D unit and has the structure shown in formula (8) below. D1: -Si-OR 3 ...(8) (R in equation (8)) 3 (This is a methyl group, an ethyl group, or a hydrogen atom.)

[0028] As a result of diligent research by the present inventors, it was found that when silica nanoparticles have an appropriate amount of polar groups at the D unit end, the charge retention and charge rise properties are improved in toner containing toner particles with magnetic material on their surface. The inventors speculate the following regarding the effect of polar groups at the D unit terminus: Compared to polar groups such as silanol groups in Q units present on the surface of the silica nanoparticle substrate, the D1 polar group at the D unit terminus exhibits moderately high hydrophobicity. This is thought to be due to the hydrophobicity derived from the carbon atoms bonded to the Si to which the polar group is attached. The moderately hydrophobic polar group at the D unit terminus has the effect of imparting electrostatic properties to its hydrophobic terminus, thereby improving the rate of charge buildup. In addition, because the D1 polar group at the D unit terminus is more hydrophobic than the silanol group present on the surface of the silica nanoparticle substrate, the influence of moisture on the silica nanoparticles is reduced, making it easier to maintain good charge retention. Furthermore, as shown in (D / S) / B after washing with chloroform, the D units are bound to the silica nanoparticle substrate to a certain extent, and the D1 at the end of the D units is located away from the surface of the silica nanoparticle substrate. Therefore, the Si-OH group of D1 suppresses the effect of moisture on the silica nanoparticle substrate compared to the silanol group present on the surface of the silica nanoparticle substrate, making it easier to maintain good charge retention.

[0029] Based on the above, the surface of silica nanoparticles is treated with a treatment agent containing D units to control the amount of silanol groups on the surface of the silica nanoparticles to an appropriate level, while also introducing a certain amount of D1 to the D unit ends. In other words, the amount of silanol groups in the silica nanoparticles, (D / S) / B, (D / S) / B after washing with chloroform, and D1 / D are set to an appropriate range. By satisfying these conditions, a toner with excellent charge retention, charge rise, and fluidity is provided even in high temperature and high humidity environments. It is considered possible.

[0030] Therefore, solid silica nanoparticles 29In the chemical shift obtained by the Si-NMR DD / MAS method, D1 is defined as the area of ​​the peak whose peak top is located in the range between -19 ppm and -17 ppm. The ratio of D1 to D (D1 / D) must be between 0.09 and 0.32. If D1 / D is less than 0.09, the amount of polar groups is small, resulting in insufficient charge build-up. Conversely, if D1 / D exceeds 0.32, the amount of polar groups is large, leading to a decrease in chargeability due to the influence of moisture in high-temperature, high-humidity environments. D1 / D is preferably between 0.10 and 0.30, more preferably between 0.11 and 0.30, and even more preferably between 0.15 and 0.25. The D1 / D ratio can be increased by increasing the content ratio of silanols and cyclic siloxanes in the treatment agent components used for surface treatment of silica microparticle substrates. On the other hand, the D1 / D ratio can be decreased by decreasing the content ratio of silanols and cyclic siloxanes in the treatment agent components used for surface treatment of silica microparticle substrates.

[0031] solid 29 The D-unit peaks obtained by the Si-NMR DD / MAS method are separated into two. The area of ​​the peak with its peak top in the chemical shift range of -19 ppm to -17 ppm is defined as D1, and the area of ​​the peak with its peak top in the range of -23 to -19 ppm is defined as D2. In silica nanoparticles, the Si atoms bonded to the OR group at the end of the D unit are known to correspond to peak D1. Furthermore, the Si atoms within the dimethylsiloxane chain are known to correspond to peak D2. Therefore, a larger integral value of peak D1 indicates a greater number of terminal polar groups in the D unit. In other words, D1 / D represents the amount of polar groups in the D unit of the treatment agent. A larger D1 / D indicates a state where the silica nanoparticles have a higher concentration of terminal polar groups in the D unit.

[0032] Toner particles contain magnetic material, and the magnetic material is present on the surface of the toner particles. When the percentage of magnetic material on the surface of the toner particles is denoted as Sm (area %), Sm is preferably between 1.0 and 7.0 area %. If the percentage of magnetic material is less than 1.0 area %, overcharging or abnormal charging is more likely to occur due to transfer bias, reducing transferability. If it exceeds 7.0 area %, charge leakage is more likely to occur in high-temperature and high-humidity environments. The magnetic material content (Sm) is preferably 1.2 to 6.9 area percent, and more preferably 2.0 to 6.0 area percent. The magnetic material content can be controlled by the magnetic material content of the toner and the toner manufacturing conditions. The magnetic material content on the surface of the toner particles can be measured by SEM observation as described later.

[0033] The magnetic material content is preferably 30 to 120 parts by mass per 100 parts by mass of toner particles. If the magnetic material content is within the above range, the magnetic material abundance (Sm) can be controlled to a desired range. On the other hand, if the magnetic material content is less than 30 parts by mass, the magnetic force of the toner becomes insufficient, and the adsorption force to the magnetic developer carrier decreases in a one-component non-contact developing method. As a result, fogging decreases. Furthermore, if the magnetic material content exceeds 120 parts by mass, the low-temperature fixing performance decreases. The magnetic material content is more preferably 40 to 110 parts by mass, and even more preferably 60 to 100 parts by mass. The magnetic material content can be measured by dissolving the toner particles in chloroform and recovering the magnetic material using a magnet, as described below.

[0034] When the coverage rate of silica microparticles on the surface of toner particles, calculated from scanning electron microscope images of the toner surface, is defined as Ssi (area %), Ssi is 30-90 area %. It is preferable that the coverage rate is 30 area % or more, which protects the magnetic material present on the surface of the toner particles and provides good chargeability and fluidity. Furthermore, if the coverage rate is 90 area % or less, sufficient heat is transferred from the fixing roller to the toner during the fixing process, improving low-temperature fixing performance. The amount of Ssi is preferably 35-70% by area, more preferably 40-60% by area, and even more preferably 45-55% by area. Ssi can be controlled by the amount of silica microparticles added to the toner particles.

[0035] The ratio of the magnetic material abundance Sm on the surface of the toner particles to the coverage rate Ssi by silica nanoparticles (Sm / Ssi) is preferably 0.010 to 0.240. When Sm / Ssi is within this range, the silica nanoparticles sufficiently cover the magnetic material present on the surface of the toner particles, thereby improving the balance between charge retention and charge rise. Sm / Ssi is more preferably 0.013 to 0.230, even more preferably 0.020 to 0.180, particularly preferably 0.040 to 0.170, and especially preferably 0.060 to 0.120.

[0036] The silica fine particle content is preferably 0.3 to 2.2 parts by mass, more preferably 0.4 to 2.0 parts by mass, and even more preferably 0.7 to 1.5 parts by mass, per 100 parts by mass of toner particles. By setting the silica fine particle content within the above range, the coverage rate of the silica fine particles on the toner particles can be controlled to a desired range.

[0037] The number-average particle size of the primary particles of the silica microparticles is preferably 5 to 50 nm, more preferably 10 to 40 nm, and even more preferably 15 to 25 nm. By adding silica microparticles with a particle size within this range to the toner particles, the toner properties such as chargeability and fluidity are improved.

[0038] The silica microparticles preferably contain both small-particle and large-particle silica microparticles. The number-average particle size of the primary particles of the small-particle silica microparticles is preferably 5 to 25 nm, and more preferably 10 to 20 nm. The number-average particle size of the primary particles of the large-particle silica microparticles is preferably greater than 25 nm and 50 nm or less, and more preferably 30 to 40 nm. The BET specific surface area of ​​small-particle silica nanoparticles is 100-500 m². 2 It is preferable that the amount be / g, and 150-300m 2 It is more preferable that the amount is / g. Also, the BET specific surface area of ​​large-particle silica fine particles is 10 to 100 m². 2 It is preferable that the amount be / g, and 30-80m 2 It is more preferable that it be / g. The mass-based content ratio of small-particle silica particles to large-particle silica particles is preferably 20:1 to 5:1, and more preferably 15:1 to 7:1. Furthermore, the BET specific surface area B of the silica nanoparticles after surface treatment is 40-200 m². 2 It is preferable that the amount be / g, and 100-150m 2 It is more preferable that it be / g.

[0039] It has been confirmed that toners to which small-particle silica microparticles are added externally result in the small-particle silica microparticles being embedded on the surface of the toner particles. This is due to stress from the carrier when used as a two-component developer, stress from the developing blade and developing sleeve when used as a one-component developer, and collisions with the inner wall of the developer unit, toner agitation blades, and toner particles themselves. To reduce this embedding of small-particle silica microparticles, it is effective to include both small-particle and large-particle silica microparticles as described above. Large silica particles act as spacer particles, preventing the toner surface to which small silica particles are attached from directly contacting the carrier, developing blade, developing roller, inner wall of the developing unit, toner stirring member, and other toners. As a result, the toner This can suppress deterioration and contamination of materials. From the viewpoint of charge uniformity, it is preferable that small-diameter silica nanoparticles and large-diameter silica nanoparticles undergo similar surface treatment. The number-average particle size of silica microparticles can be controlled by changing the conditions in the silica microparticle manufacturing process, such as the classification process, and can also be controlled by adjusting the mixing ratio of small-particle and large-particle silica microparticles, as well as the number-average particle size of each.

[0040] It is more preferable that the silica nanoparticles are surface-treated with at least the compound represented by formula (3) below. [ka]

[0041] In equation (3), R 1 , R 2 Each of these is independently a carbinol group, a hydroxyl group, an epoxy group, a carboxyl group, an alkyl group (preferably having 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms), or a hydrogen atom. m is the average number of repeating units and is an integer from 1 to 200 (preferably 30 to 150, more preferably 70 to 130).

[0042] The surface treatment agent of formula (3) can further improve the electrostatic stability in high-temperature and high-humidity environments. The surface treatment agent used is not particularly limited as long as it is a compound represented by formula (3), and known compounds can be used. These may be used alone or in combination of two or more. In addition, two or more surface treatment agents with different functional groups may be used sequentially or in mixture, or two or more surface treatment agents having the same functional group but different viscosity and molecular weight distribution may be used sequentially or in mixture. Whether or not a surface has been treated with the compound shown in equation (3) can be determined by methods such as analyzing the mass spectrum obtained by gas chromatography-mass spectrometry.

[0043] When silica fine particles are washed with chloroform, the carbon content immobilization rate (C content immobilization rate) is preferably 30-70%, more preferably 50-70%, and even more preferably 60-65%. The carbon elements contained in silica nanoparticles originate from the carbon in the surface treatment agent and can be controlled by changing the structure of the surface treatment agent and the treatment conditions (treatment temperature, treatment time, viscosity, amount added, etc.). Here, the carbon fixation rate is considered to correspond to the amount of surface treatment agent that is chemically or physically firmly bonded to the silica substrate surface. By controlling the carbon content fixation rate by the surface treatment agent within the above range for silica microparticles, the coefficient of friction between the silica microparticles and the components inside the toner cartridge becomes appropriate. As a result, the fusion adhesion of silica microparticles and toner with externally added silica microparticles to the components inside the toner cartridge can be suppressed, and cleaning performance is also improved. Furthermore, by reducing the amount of silanol groups on the surface of the silica microparticle substrate, it becomes easier to control the D1 / D ratio, and overcharging in low humidity environments is more easily suppressed. As a result, the stability of the electrostatic charge is further improved.

[0044] The toner preferably contains strontium titanate fine particles in addition to silica fine particles on the surface of the toner particles. The silica fine particle content in the toner is determined by X-ray fluorescence analysis. The ratio of elemental strength (Si / Sr) to the content of strontium titanate fine particles is preferably 0.10 to 2.30, more preferably 0.10 to 1.50, and even more preferably 0.10 to 0.80. The presence of strontium titanate microparticles on the surface of toner particles provides a polishing and removal effect on deposits on components within the device, improving cleaning performance. Furthermore, the presence of an appropriate amount of strontium titanate microparticles improves charge retention. By controlling the Si / Sr ratio within the above range, both cleaning performance and charge retention can be achieved. The content ratio of silica nanoparticles to strontium titanate nanoparticles is calculated from the signal intensity ratio of Si atoms and Sr atoms in the strontium titanate nanoparticles obtained by X-ray fluorescence analysis of the toner. The measurement method for X-ray fluorescence analysis will be described later. The Si / Sr ratio can be controlled by adding extra silica nanoparticles or strontium titanate nanoparticles.

[0045] The content of strontium titanate fine particles is preferably 0.01 to 0.75 parts by mass, more preferably 0.03 to 0.71 parts by mass, even more preferably 0.06 to 0.60 parts by mass, particularly preferably 0.10 to 0.50 parts by mass, and especially preferably 0.14 to 0.40 parts by mass, per 100 parts by mass of toner particles. By setting the range as described above, it is possible to achieve both cleaning performance and static charge retention.

[0046] The toner particles may contain a colorant. Any colorant can be used. Examples of colorants include organic pigments, organic dyes, and inorganic pigments, but there are no particular limitations, and any known colorant can be used. Among these, the use of a magnetic material is preferred. This is because, when a magnetic material is present on the surface of the toner particles, it not only acts as a colorant but also has the effect of moderately reducing the surface's electrostatic charge. The preferred amount to add is 30 parts by mass or more and 150 parts by mass or less per 100 parts by mass of the binder resin.

[0047] The number-average particle size of the primary magnetic particles present on the surface of the toner particles is preferably 50 to 500 nm, more preferably 50 to 300 nm, and even more preferably 100 to 200 nm. The number-average particle size of primary magnetic particles present on the surface of toner particles can be measured using a transmission electron microscope.

[0048] The remanent magnetization (σr) of the magnetic material present on the surface of toner particles is 2 to 22 Am. 2It is preferable that the value is / kg, which is 4-20Am 2 It is more preferable that the value be / kg, which is 4-18Am 2 It is even more preferable that the value be / kg, which is 6-10Am 2 It is particularly preferable that the value be / kg. By controlling the σr of the magnetic material within the above range, the toner is developed and transferred in a dispersed manner while maintaining appropriate developability. As a result, the wetting and spreading of the toner is promoted during the fixing process, and low-temperature fixing performance is improved. The remanent magnetization of a magnetic material can be controlled by controlling the Si content in the magnetic material.

[0049] The Si content in the magnetic material present on the surface of the toner particles is preferably 0.0 to 5.0 mass%, more preferably 0.5 to 4.0 mass%, and even more preferably 1.0 to 3.0 mass%. By controlling the Si content in the magnetic material within the above range, the σr of the magnetic material can be controlled within a desired range. Furthermore, having an appropriate amount of Si in the magnetic material slows down the transfer of charge between it and the externally added silica fine particles, improving charge retention. The Si content in a magnetic material can be adjusted by controlling the amount of SiO2 added during the manufacturing process.

[0050] The ratio of the Si content Msi [mass%] in the magnetic material present on the surface of toner particles to (D / S) / B, Msi / (D / S) / B, is 1.8 × 10⁻⁶ 2 The above 4.8 × 10 3 The following may be true: 2.1 × 10 2 The above 1.5 × 10 3 The following is preferable. By controlling within the above range, charge transfer between silica magnetic materials is optimized, and image density is improved when left in a high-temperature, high-humidity environment.

[0051] Examples of magnetic materials include at least one selected from the group consisting of iron oxides such as magnetite, maghemite, and ferrite; metals such as iron, cobalt, and nickel; alloys of these metals with metals such as aluminum, copper, magnesium, tin, zinc, beryllium, calcium, manganese, selenium, titanium, tungsten, and vanadium; and mixtures thereof. Furthermore, the magnetic material may be subjected to known surface treatments as needed.

[0052] The silica nanoparticles are preferably hydrophobized silica particles obtained by heat-treating a silica nanoparticle substrate with a cyclic siloxane, followed by heat-treating with silicone oil. In other words, the silica nanoparticles are preferably silicone oil-treated products of silica nanoparticles treated with a cyclic siloxane. Furthermore, when the amount of cyclic siloxane processed per 100 parts by mass of silica fine particles is X parts by mass and the amount of silicone oil processed is Y parts by mass, the ratio of X to Y (X / Y) is preferably 0.60 to 1.20. More preferably 0.65 to 1.15, and even more preferably 0.70 to 1.00. By controlling X / Y within the above range, the value of D1 / D can be controlled to the desired range.

[0053] The silica microparticle substrate that serves as the base material before surface treatment with silicone oil or the like can be any silica microparticle obtained by known methods without any particular limitations. For example, fumed silica, wet-process silica, and sol-gel silica are typical examples. Furthermore, these silica particles may be partially or entirely molten silica.

[0054] For the silica microparticle substrate, it is possible to appropriately select and use one from among fumed silica, wet silica, etc., depending on the required characteristics of the individual toner. In particular, fumed silica has excellent fluidity-imparting effects and is suitable as a silica microparticle substrate used as an external additive for electrophotographic toners.

[0055] Silica nanoparticles are used in which the silica nanoparticle substrate has been surface-treated to impart hydrophobicity and fluidity. Surface treatment methods include chemical treatment with silicon compounds that react with or physically adsorb to the silica nanoparticle substrate. The method for surface treatment of the silica microparticle substrate is not particularly limited and can be carried out by contacting the silica microparticles with a surface treatment agent containing siloxane bonds. From the viewpoint of uniformly treating the surface of the silica microparticle substrate and easily achieving the above physical properties, it is preferable to contact the silica microparticle substrate with the surface treatment agent in a dry manner. As will be described later, examples of methods include contacting the silica microparticle substrate with the vapor of the surface treatment agent, or spraying the silica microparticle substrate with the undiluted solution or a diluted solution of the surface treatment agent with various solvents.

[0056] As a surface treatment method for a silica microparticle substrate, the method for producing silica microparticles preferably comprises a first step of surface treatment (dry treatment) of the silica microparticle substrate with a cyclic siloxane, and a second step of surface treatment (dry treatment) of the silica microparticle substrate after cyclic siloxane treatment with silicone oil. The silica microparticles are preferably the silicone oil-treated product of the silica microparticles treated with cyclic siloxane. The method for producing toner preferably includes a step of preparing silica microparticles obtained by the above method.

[0057] Regarding the first treatment, high-temperature treatment with a low molecular weight cyclic siloxane can efficiently reduce the silanol groups on the surface of the silica nanoparticle substrate, and short dimethylsiloxane chains with OH groups at their ends can be added to the surface of the silica nanoparticle substrate. The treatment temperature for cyclic siloxane on the surface of the silica nanoparticle substrate is preferably 300°C or higher. A temperature of 300°C or higher effectively reduces the silanol groups on the surface of the silica nanoparticle substrate. Furthermore, a treatment temperature of 300°C or higher allows for the formation and cleavage of siloxane bonds, enabling more uniform treatment of the silica nanoparticle substrate surface while uniformly controlling the siloxane chain length. The treatment temperature for the cyclic siloxane on the surface of the silica nanoparticle substrate is more preferably 310°C or higher, even more preferably 320°C or higher, and even more preferably 330°C or higher. There is no particular upper limit, but it is preferably 380°C or lower, and more preferably 350°C or lower.

[0058] After the above cyclic siloxane treatment, the silica nanoparticle substrate treated with the cyclic siloxane is heat-treated with silicone oil as a second treatment. The silicone oil binds to the terminal OH groups of the components reacted with the cyclic siloxane in the first treatment, allowing the long-chain dimethylsiloxane component to be introduced to the surface of the silica nanoparticles. The temperature during the silicone oil treatment of the silica nanoparticle substrate surface is preferably 300°C or higher, more preferably 320°C or higher, and even more preferably 330°C or higher. There is no particular upper limit, but it is preferably 380°C or lower, and more preferably 350°C or lower. By controlling the processing amount X of the cyclic siloxane and the processing amount Y of the silicone oil mentioned above, the silanol component on the surface of the silica microparticle substrate can be reduced, and the amounts of D units and D1 mentioned above can be controlled. This allows for improved electrostatic stability without reducing the fluidity of the toner with a small amount of surface treatment.

[0059] As the cyclic siloxane, at least one can be selected from the group consisting of low molecular weight cyclic siloxanes with up to 10 membered rings, such as hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, and decamethylcyclopentasiloxane. Among these, octamethylcyclotetrasiloxane is preferred. Furthermore, silicone oil refers to an oily substance having a molecular structure with siloxane bonds as its main chain, and any silicone oil that satisfies formula (3) above can be used without any particular restrictions as long as it is generally available. Specifically, examples include silicone oils consisting of a linear polysiloxane skeleton, such as dimethyl silicone oil, alkyl-modified silicone oil, olefin-modified silicone oil, fatty acid-modified silicone oil, alkoxy-modified silicone oil, polyether-modified silicone oil, and carbinol-modified silicone oil.

[0060] The processing time in the first and second processes varies depending on the processing temperature and the reactivity of the surface treatment agent used, but is preferably 5 minutes to 300 minutes, more preferably 30 minutes to 240 minutes, and even more preferably 50 minutes to 200 minutes. The above-mentioned processing temperature and processing time for the surface treatment are preferable from the viewpoint of allowing the treatment agent to react sufficiently with the silica fine particle substrate, and from the viewpoint of production efficiency.

[0061] In the first treatment, contact of the surface treatment agent with the silica microparticle substrate is preferably carried out by contacting the vapor of the surface treatment agent under reduced pressure or in an inert gas atmosphere such as a nitrogen atmosphere. By using the vapor contact method, it is easy to remove surface treatment agents that do not react with the silica microparticle surface, and the surface of the silica microparticles can be appropriately covered with modifying groups having appropriate polarity. When using the vapor contact method, it is preferable to perform the treatment at a treatment temperature above the boiling point of the surface treatment agent. The vapor contact may be carried out in multiple stages. When contacting the vapor of a surface treatment agent under an inert gas atmosphere such as a nitrogen atmosphere, the container It is preferable that the pressure (gauge pressure) due to the vapor of the surface treatment agent inside be 50 to 300 kPa or less, and more preferably 150 to 250 kPa.

[0062] The toner particles may contain a binder resin. Examples of binder resins include vinyl resins and polyester resins, but the resin is not particularly limited and any known resin can be used. Specifically, styrene copolymers such as polystyrene, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-octyl methacrylate copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-maleic acid copolymer, and styrene-maleic acid ester copolymer, as well as polyacrylic acid esters, polymethacrylate esters, and polyvinyl acetate can be used, and these can be used individually or in combination. Among these, styrene copolymers and polyester resins are particularly preferred in terms of developing characteristics and fixing properties.

[0063] It is preferable to add a charge control agent to the toner particles. Effective charge control agents for negative charging include organometallic complex compounds and chelate compounds, such as monoazo metal complex compounds, acetylacetone metal complex compounds, and metal complex compounds of aromatic hydroxycarboxylic acids or aromatic dicarboxylic acids. Examples of commercially available products include Spilon Black TRH, T-77, T-95 (Hodogaya Chemical Co., Ltd.), and BONTRON® S-34, S-44, S-54, E-84, E-88, E-89 (Orient Chemical Co., Ltd.).

[0064] Furthermore, examples of positively charged charge control agents include modified products of nigrosine and fatty acid metal salts; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate and tetrabutylammonium tetrafluoroborate, and onium salts such as phosphonium salts which are analogs thereof, and lake pigments thereof; triphenylmethane dyes and lake pigments thereof (lake agents include phosphotungstic acid, phosphomolybdenumic acid, phosphotungstenmolybdenumic acid, tannic acid, lauric acid, gallic acid, ferricyanic acid, ferrocyanic acid, ferrocyanic compounds, etc.); metal salts of higher fatty acids; diorganostin oxides such as dibutyltin oxide, dioctyltin oxide, and dicyclohexyltin oxide; and organostin borates such as dibutyltin borate, dioctyltin borate, and dicyclohexyltin borate. Specific examples of commercially available products include TP-302, TP-415 (Hodogaya Chemical Co., Ltd.), BONTRON® N-01, N-04, N-07, P-51 (Orient Chemical Co., Ltd.), and Copy Blue PR (Clariant Co., Ltd.).

[0065] These charge control agents can be used individually or in combination of two or more. From the viewpoint of the toner's charge level, the amount of these charge control agents used is preferably 0.1 to 10.0 parts by mass per 100 parts by mass of binder resin, and more preferably 0.1 to 5.0 parts by mass.

[0066] A release agent may be added to the toner particles as needed to improve adhesion. The release agent is not particularly limited, and known release agents can be used. Specifically, these include petroleum-based waxes such as paraffin wax, microcrystalline wax, and petrolactam, and their derivatives; montan wax and its derivatives; hydrocarbon waxes and their derivatives produced by the Fischer-Tropsch process; polyolefin waxes represented by polyethylene and polypropylene, and their derivatives; natural waxes such as carnauba wax and candelilla wax, and their derivatives; and ester waxes. Here, derivatives and This includes oxides, block copolymers with vinyl monomers, and graft-modified products. In addition, as ester waxes, monofunctional ester waxes, difunctional ester waxes, and polyfunctional ester waxes such as tetrafunctional and hexafunctional waxes can be used.

[0067] The melting point of the release agent is preferably 60 to 140°C, and more preferably 70 to 130°C. A melting point of 60 to 140°C makes it easier for the toner to plasticize during fixing, improving fixing performance. Furthermore, a melting point within this range is preferable because it reduces the likelihood of the release agent seeping out even during long-term storage.

[0068] The toner may contain silica nanoparticles and strontium titanate nanoparticles, as well as other external additives such as inorganic nanoparticles other than silica nanoparticles and strontium titanate nanoparticles. The toner can be obtained by externally adding silica nanoparticles, strontium titanate nanoparticles, and, if necessary, inorganic nanoparticles other than silica nanoparticles and strontium titanate nanoparticles to the toner particles. Examples of inorganic nanoparticles include hydrotalcite compounds, fatty acid metal salts, alumina, and metal oxide nanoparticles (inorganic nanoparticles) such as titanium dioxide, zinc oxide nanoparticles, cerium oxide nanoparticles, and calcium carbonate nanoparticles.

[0069] Furthermore, other external additives can include composite oxide nanoparticles using two or more metals, or two or more nanoparticles selected in any combination from this group. Furthermore, resin microparticles or organic-inorganic composite microparticles, which are a combination of resin microparticles and inorganic microparticles, can also be used. Preferably, the toner contains titanium dioxide particles in addition to silica microparticles as an external additive. Other external additives may be hydrophobized using a hydrophobic treatment agent.

[0070] Examples of hydrophobic treatment agents include chlorosilanes such as methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, t-butyldimethylchlorosilane, and vinyltrichlorosilane; Tetramethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, o-methylphenyltrimethoxysilane, p-methylphenyltrimethoxysilane, n-butyltrimethoxysilane, i-butyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, dodecyltrimethoxysilane, tetraethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, i-butyltrimethoxysilane Alkoxysilanes such as tiltriethoxysilane, decyltriethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, and γ-(2-aminoethyl)aminopropylmethyldimethoxysilane; Silazanes such as hexaethyldisilazane, hexapropyldisilazane, hexabutyldisilazane, hexapentyldisilazane, hexahexyldisilazane, hexacyclohexyldisilazane, hexaphenyldisilazane, divinyltetramethyldisilazane, and dimethyltetravinyldisilazane; Dimethyl silicone oil, methyl hydrogen silicone oil, methylphenyl silicone oil, alkyl-modified silicone oil, chloroalkyl-modified silicone oil, chlorophenyl-modified silicone oil, fatty acid-modified silicone oil, polyether-modified silicone oil, alkoxy-modified silicone oil, carbinol-modified silicone oil, amino-modified silicone oil, fluorine-modified silicone oil, and terminally reactive Silicone oils such as silicone oil; Siloxanes such as hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, hexamethyldisiloxane, and octamethyltrisiloxane; Examples of fatty acids and their metal salts include long-chain fatty acids such as undecylic acid, lauric acid, tridecylic acid, dodecylic acid, myristic acid, palmitic acid, pentadecylic acid, stearic acid, heptadecylic acid, arachidic acid, montanic acid, oleic acid, linoleic acid, and arachidonic acid, as well as salts of the above fatty acids with metals such as zinc, iron, magnesium, aluminum, calcium, sodium, and lithium.

[0071] Among these, alkoxysilanes, silazanes, and silicone oils are preferred because they facilitate hydrophobic treatment. These hydrophobic agents may be used individually or in combination of two or more. The content of external additives is preferably 0.05 to 20.0 parts by mass per 100 parts by mass of toner particles. The content of external additives other than silica fine particles and strontium titanate fine particles is preferably 0.1 to 1.0 parts by mass, and more preferably 0.1 to 0.5 parts by mass per 100 parts by mass of toner particles.

[0072] The weight-average particle size (D4) of the toner is preferably 3.0 to 12.0 μm, and more preferably 4.0 to 10.0 μm. When the weight-average particle size (D4) is within the above range, good fluidity is obtained, and the latent image can be developed faithfully.

[0073] The method for manufacturing toner is not particularly limited, and known manufacturing methods can be employed. Examples of toner manufacturing methods include grinding, polymerization, dispersion polymerization, association agglutination, dissolution suspension, suspension polymerization, and emulsification agglutination. The following is a specific example of a pulverization method for producing toner through a melting and kneading process and a pulverization process, but it is not limited to this.

[0074] For example, the binder resin and, if necessary, colorants, release agents, charge control agents, and other additives are thoroughly mixed using a mixer such as a Henschel mixer or a ball mill (mixing step). The resulting mixture is then melt-kneaded using a thermal kneader such as a twin-screw extruder, heated rolls, kneader, or extruder (melt-kneading step).

[0075] After the obtained molten mixture is cooled and solidified, it is crushed using a pulverizer (crushing step) and then classified using a classifier (classification step) to obtain toner particles. Furthermore, if necessary, the toner particles and external additives are mixed using a mixer such as a Henschel mixer to obtain toner.

[0076] Examples of mixing machines include: FM mixer (Nippon Coke Industries Co., Ltd.); Super Mixer (Kawata Co., Ltd.); Ribocone (Okawara Seisakusho Co., Ltd.); Nauter mixer, Turbulizer, Cyclomix (Hosokawa Micron Co., Ltd.); Spiral Pin Mixer (Taiheiyo Kiko Co., Ltd.); Redigge mixer (Matsubo Co., Ltd.).

[0077] Examples of hot mixing machines include: KRC kneader (manufactured by Kurimoto Iron Works); Buss-Co kneader (manufactured by Buss); TEM type extruder (manufactured by Toshiba Machine Co.); TEX twin-screw mixer (manufactured by Japan Steel Works); PCM mixer (manufactured by Ikegai Iron Works); three-roll mill, mixing roll mill, kneader (manufactured by Inoue Seisakusho); Nidex (manufactured by Mitsui Mining Co.); MS Type pressurized kneader, nidar-ruder (manufactured by Moriyama Seisakusho Co., Ltd.); Banbury mixer (manufactured by Kobe Steel, Ltd.).

[0078] Examples of grinders include: counter jet mills, micron jets Inomer (manufactured by Hosokawa Micron Corporation); IDS type mill, PJM jet pulverizer (manufactured by Nippon Pneumatic Mfg. Co., Ltd.); Cross Jet Mill (manufactured by Kurimoto Iron Works Co., Ltd.); Ulmax (manufactured by Nisso Engineering Co., Ltd.); SK Jet-O-Mill (manufactured by Seishin Enterprise Co., Ltd.); Cryptron (manufactured by Kawasaki Heavy Industries Co., Ltd.); Turbo Mill (manufactured by Turbo Industries Co., Ltd.); Super Rotor (manufactured by Nisshin Engineering Co., Ltd.).

[0079] Examples of classifiers include: Classil, Micron Classifier, Spedick Classifier (manufactured by Seishin Corporation); Turbo Classifier (manufactured by Nisshin Engineering Co., Ltd.); Micron Separator, Turboplex (ATP), TSP Separator (manufactured by Hosokawa Micron Corporation); Elbow Jet (manufactured by Nippon Steel Mining Co., Ltd.), Dispersion Separator (manufactured by Nippon Pneumatic Mfg. Co., Ltd.); and YM Microcut (manufactured by Yaskawa Trading Co., Ltd.).

[0080] Additionally, the following sieving devices may be used to separate coarse particles: Ultrasonic (manufactured by Koei Sangyo Co., Ltd.); Resona Sieve, Gyro Shifter (manufactured by Tokuju Kogyo Co., Ltd.); Vibrasonic System (manufactured by Dalton Co., Ltd.); Soniclean (manufactured by Shinto Kogyo Co., Ltd.); Turbo Screener (manufactured by Turbo Kogyo Co., Ltd.); Micro Shifter (manufactured by Makino Sangyo Co., Ltd.); Circular Vibrating Sieve.

[0081] Toner particles are manufactured by suspension polymerization, for example, as shown below. A polymerizable monomer composition is prepared by uniformly dissolving or dispersing polymerizable monomers, such as styrene monomers, (meth)acrylic acid ester monomers, colorants, wax components, and polymerization initiators, using a disperser such as a homogenizer, ball mill, or ultrasonic disperser, to produce a binder resin. After granulating the polymerizable monomer composition particles by dispersing the polymerizable monomer composition in an aqueous medium, toner particles are obtained by polymerizing the polymerizable monomers in the particles made of the polymerizable monomer composition.

[0082] In this case, it is preferable that the polymerizable monomer composition is prepared by mixing a dispersion in which a colorant is dispersed in a first polymerizable monomer (or a portion of the polymerizable monomers) with at least a second polymerizable monomer (or the remaining polymerizable monomers). That is, by thoroughly dispersing the colorant in the first polymerizable monomer and then mixing it with the second polymerizable monomer together with other toner materials, the colorant can be present in the polymerized particles in a better dispersed state.

[0083] Toner particles can be obtained by filtering, washing, drying, and classifying the polymerized particles using known methods. Toner can then be obtained by externally adding silica fine particles to the toner particles obtained as described above.

[0084] The addition of external additives such as silica microparticles to toner particles can be performed by mixing the toner particles and the external additive using a mixer like the one described below. Examples of mixing machines include: Henschel mixer (manufactured by Mitsui Mining Co., Ltd.); Super Mixer (manufactured by Kawata Co., Ltd.); Ribocone (manufactured by Okawara Seisakusho Co., Ltd.); Nauter mixer, Turbulizer, Cyclomix (manufactured by Hosokawa Micron Co., Ltd.); Spiral Pin Mixer (manufactured by Taiheiyo Kiko Co., Ltd.); and Redigge mixer (manufactured by Matsubo Co., Ltd.).

[0085] From the viewpoint of the dispersibility of the external additive, the mixing time in the external additive process is preferably adjusted to a range of 0.5 minutes to 10.0 minutes, and more preferably to a range of 1.0 minute to 5.0 minutes. The method for manufacturing toner comprises the steps of obtaining toner particles, preparing silica fine particles, and externally adding and mixing the silica fine particles to the obtained toner particles to obtain toner.

[0086] Next, we will describe the measurement methods for each physical property. <Solid silica microparticles> 29 (D / S) / B and D measured by Si-NMR DD / MAS Method for calculating 1 / D > Solid silica nanoparticles 29 Si-NMR measurements are performed by separating silica nanoparticles from the toner surface. Below, we will discuss the method for separating silica nanoparticles from the toner surface and the solid-state method. 29 This document describes Si-NMR measurements.

[0087] <Method for separating silica microparticles from the toner surface> When using silica microparticles separated from the surface of the toner as the measurement sample, the separation of silica microparticles from the toner is performed using the following procedure. Add 1.6 kg of sucrose (manufactured by Kishida Chemical Co., Ltd.) to 1 L of deionized water and dissolve it over a water bath to prepare a concentrated sucrose solution. Place 31 g of this concentrated sucrose solution and 6 mL of Contaminon N (a 10% by mass aqueous solution of a pH 7 neutral detergent for cleaning precision measuring instruments, consisting of a nonionic surfactant, anionic surfactant, and organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) into a centrifugal separator tube to prepare a dispersion. Add 10 g of toner to this dispersion and break up any clumps of toner with a spatula or similar tool. The centrifugation tube is placed in an Iwaki Sangyo Co., Ltd. "KM Shaker" (model: V.SX) and shaken for 20 minutes at a rate of 350 strokes per minute. After shaking, the solution is transferred to a 50 mL glass tube for the swing rotor and centrifuged in a centrifuge at 3500 rpm for 30 minutes.

[0088] After centrifugation, toner particles are present in the uppermost layer of the glass tube, while an inorganic microparticle mixture containing silica microparticles is present in the lower aqueous solution layer. The upper and lower aqueous solutions are separated and dried, obtaining toner particles from the upper layer and the inorganic microparticle mixture from the lower layer. The obtained toner particles are used to measure the abundance of magnetic material, as described later. The centrifugation process is repeated so that the total amount of inorganic microparticle mixture obtained from the lower layer is 10 g or more.

[0089] Next, 10 g of the obtained inorganic fine particle mixture is added to a dispersion containing 100 mL of deionized water and 6 mL of Contaminon N and dispersed. The resulting dispersion is transferred to a 50 mL glass tube for a swing rotor and centrifuged in a centrifuge at 3500 rpm for 30 minutes. After centrifugation, silica microparticles are present in the uppermost layer of the glass tube, while other inorganic microparticles are present in the lower aqueous solution layer. The upper aqueous solution is collected, and centrifugation is repeated as needed to ensure sufficient separation. After drying the dispersion, the silica microparticles are collected. Next, the solid silica microparticles recovered from the toner particles. 29 The Si-NMR measurement will be performed under the measurement conditions shown below.

[0090] <Solid 29 DD / MAS measurement conditions for Si-NMR measurement> Solid 29 The DD / MAS measurement conditions for Si-NMR measurement are as follows. Apparatus: JNM-ECX5002 (JEOL RESONANCE) Temperature: Room temperature Measurement method: DD / MAS method 29 Si 45° Sample tube: Zirconia 3.2 mm φ Sample: Filled in the test tube in powder form Sample rotation speed: 10 kHz Relaxation delay: 180 s Scan: 2000 Standard substance for calibration: DSS (Sodium 3-(trimethylsilyl)-1-propanesulfonate)

[0091] After the above measurement, from the solid Si-NMR spectrum of silica microparticles, a plurality of silane components with different substituents and bonding groups are peak-separated into the following M unit, D unit, T unit, and Q unit by curve fitting. 29 From the Si-NMR spectrum of the solid, a plurality of silane components with different substituents and bonding groups are peak-separated into the following M unit, D unit, T unit, and Q unit by curve fitting. Curve fitting is performed using EXcalibur for Windows (registered trademark) version 4.2 (EX series), software for JNM-EX400 manufactured by JEOL Ltd. Click "1D Pro" from the menu icon to load the measurement data. Next, select "Curve fitting function" from "Command" in the menu bar to perform curve fitting. Curve fitting is performed for each component so that the difference (synthetic peak difference) between the synthetic peak obtained by synthesizing each peak obtained by curve fitting and the peak of the measurement result is minimized. M unit: (R i )(R j )(R k )SiO 1 / 2 Formula (4) D unit: (R g )(R h )Si(O 1 / 2 )2 Formula (5) T unit: R m Si(O 1 / 2 )3 formula (6) Q unit: Si(O 1 / 2 )4 formula (7) In formula (4), (5), and (6), R i , R j , R k , R g , R h , R m represents an alkyl group such as a hydrocarbon group having 1 to 6 carbon atoms bonded to silicon, a halogen atom, a hydroxy group, an acetoxy group, or an alkoxy group, etc.

[0092] Also, for the D unit peak, waveform separation is performed individually by the Voigt function, and the area of peak D1 in the range exceeding -19 ppm and not exceeding -17 ppm is calculated. After peak separation, the integral value of the D unit existing in the range of -25 to -15 ppm in chemical shift is calculated. Also, the total sum S of all integral values of M, D, T, and Q units existing in the range of -140 to 100 ppm is calculated, and the BET specific surface area B (m 2 / g) of the silica fine particles is obtained by the method described later, and the ratio (D / S) / B is calculated. Also, the ratio D1 / D is calculated from the integral values of peak D1 and D obtained by waveform separation. Furthermore, after performing the following cleaning operation with chloroform on the silica fine particles, the same NMR measurement is performed to calculate (D / S) / B after cleaning.

[0093] <Washing of silica fine particles with chloroform> Put 100 mL of chloroform and 1 g of silica fine particles into a centrifuge tube and stir with a spatula or the like. Set the centrifuge tube on a KM Shaker and shake for 20 minutes under the condition of 350 reciprocations per minute. After shaking, transfer it to a glass tube for a swinging rotor and perform centrifugation in a centrifuge under the conditions of 3500 rpm for 30 minutes. Discard the supernatant, add 100 mL of chloroform again and shake, and perform the centrifugation operation twice. Collect the precipitated silica fine particles and perform vacuum drying at 40 °C for 24 hours to obtain the silica fine particles after washing.

[0094] <Method for measuring fragment ions on the surface of silica nanoparticles using time-of-flight secondary ion mass spectrometry (TOF-SIMS)> TOF-SIMS measurement of silica microparticles is performed using silica microparticles separated from the toner using the method described above for separating silica microparticles from the toner surface. For measuring fragment ions on the surface of silica nanoparticles using TOF-SIMS, we use the TRIFT-IV from ULVAC-PHI. The analysis conditions are as follows: Sample preparation: Silica microparticles are attached to an indium sheet. Primary ion: Au ion Acceleration voltage: 30kV Charge neutralization mode: On Measurement mode: Positive Raster: 200 μm Measurement time: 60s From the obtained mass profile of secondary ion mass / secondary ion charge number (m / z), we confirm whether fragment ions corresponding to the structure shown in equation (1) are observed. For example, if the surface treatment agent is polydimethylsiloxane or cyclic siloxane, fragment ions are observed at positions such as m / z = 147, 207, and 221.

[0095] <Method for measuring the specific surface area of ​​silica microparticles using the BET method> The BET specific surface area of ​​silica nanoparticles is measured using the following procedure. The "Automatic Specific Surface Area and Pore Distribution Measurement System TriStar3000 (manufactured by Shimadzu Corporation)," which employs a constant-volume gas adsorption method, is used as the measurement device. Setting the measurement conditions and analyzing the measurement data are performed using the dedicated software "TriStar3000 Version 4.00" included with the device. A vacuum pump, nitrogen gas piping, and helium gas piping are connected to the device. Nitrogen gas is used as the adsorption gas, and the value calculated using the BET multi-point method is defined as the BET specific surface area. The BET specific surface area is calculated as follows: First, nitrogen gas is adsorbed onto silica nanoparticles, and the equilibrium pressure P (Pa) in the sample cell and the amount of nitrogen adsorbed by the magnetic material V are used. a (mol·g -1 ) is measured. Then, the equilibrium pressure P (Pa) in the sample cell is measured to match the saturated vapor pressure of nitrogen P o The relative pressure P is the value obtained by dividing by (Pa). r With the horizontal axis representing the amount of nitrogen adsorption V, a (mol·g -1 An adsorption isotherm is obtained with ) as the vertical axis. Next, the monolayer adsorption amount V is the amount of adsorption required to form a monolayer on the surface of silica nanoparticles. m (mol·g -1 ) is calculated by applying the following BET formula. P r / V a (1-P r ) = 1 / (V m ×C)+(C-1)×P r / (V m ×C) (Here, C is the BET parameter, which is a variable that varies depending on the type of sample being measured, the type of adsorbed gas, and the adsorption temperature.) The BET formula uses P as the X-axis. r , Y axis P r / V a (1-P r If we assume that the slope is (C-1) / (V m ×C), the intercept is 1 / (V m This can be interpreted as a straight line (×C) (this line is called a BET plot). The slope of a line = (C-1) / (V m ×C) Intercept of a straight line = 1 / (V m ×C) P r Measured values ​​and P r / V a (1-P r By plotting the measured values ​​of ) on a graph and drawing a straight line using the least squares method, the slope and intercept values ​​of that line can be calculated. Solving the simultaneous equations for the slope and intercept using these values, we get V m And C can be calculated. Furthermore, V calculated above m and the molecular occupied cross-section of a nitrogen molecule (0.162 nm2 ) Based on the following formula, the BET specific surface area S(m²) of silica nanoparticles is calculated. 2 Calculate the value (per g). S=V m ×N×0.162×10 -18 (Here, N is Avogadro's number (mol) -1 ) is. )

[0096] Measurements using this device are performed specifically according to the following procedure. Thoroughly wash and dry a dedicated glass sample cell (stem diameter 3 / 8 inch, volume 5 mL) and accurately weigh its tare. Then, using a funnel, place 0.1 g of silica microparticles into the sample cell. Place the sample cell containing the silica microparticles into the "Vacuprep 061 (Shimadzu Corporation)" pretreatment device, which is connected to a vacuum pump and nitrogen gas piping, and continue vacuum degassing at 23°C for 10 hours. During vacuum degassing, the valve is adjusted to gradually remove the silica particles while preventing them from being drawn into the vacuum pump. The pressure inside the cell gradually decreases as degassing progresses, eventually reaching 0.4 Pa (approximately 3 mTorr). After vacuum degassing is complete, nitrogen gas is gradually injected to return the sample cell to atmospheric pressure, and the sample cell is removed from the pretreatment device. The mass of this sample cell is then accurately weighed, and the exact mass of the silica nanoparticles is calculated from the difference with the tare weight. At this time, the silica nanoparticles in the sample cell are exposed to the water in the atmosphere. To prevent contamination, the sample cell should be sealed with a rubber stopper during weighing.

[0097] Next, a special isothermal jacket is attached to the sample cell containing silica nanoparticles. Then, a special filler rod is inserted into the sample cell, and the sample cell is set into the analysis port of the apparatus. The isothermal jacket is a cylindrical component with a porous inner surface and an impermeable outer surface, capable of drawing up liquid nitrogen to a certain level by capillary action. Next, the free space of the sample cell, including the connecting device, is measured. The free space is calculated by first measuring the volume of the sample cell using helium gas at 23°C, then cooling the sample cell with liquid nitrogen and similarly measuring the volume of the sample cell using helium gas, and converting the difference between these volumes. The saturated vapor pressure of nitrogen P is also measured. o (Pa) is the P built into the device. o It is measured separately and automatically using a tube.

[0098] Next, after vacuum degassing the sample cell, the sample cell is cooled with liquid nitrogen while continuing vacuum degassing. Then, nitrogen gas is gradually introduced into the sample cell to adsorb nitrogen molecules onto the silica nanoparticles. During this process, the equilibrium pressure P (Pa) is measured at all times to obtain an adsorption isotherm, which is then converted into a BET plot. Note that the relative pressure P from which the data is collected r The points are set to a total of 6 points: 0.05, 0.10, 0.15, 0.20, 0.25, and 0.30. A straight line is drawn from the obtained measurement data using the least squares method, and the slope and intercept of that line are used to determine V m Calculate this V. m Using the value of , the BET specific surface area of ​​the silica nanoparticles is calculated as described above.

[0099] <Method for measuring the Si-OH content of silica nanoparticles> The Si-OH content of silica nanoparticles can be determined using the silica nanoparticles separated from the toner by the method described above, and then by the following method. Prepare sample solution 1 by mixing 25.0 g of ethanol and 75.0 g of a 20% sodium chloride aqueous solution. Also, prepare sample solution 2 by accurately weighing 2.00 g of silica fine particles into a glass bottle and adding a solvent mixture of 25.0 g of ethanol and 75.0 g of a 20% sodium chloride aqueous solution. Stir sample solution 2 with a magnetic stirrer for at least 5 minutes to disperse the silica fine particles. Next, for each of sample solutions 1 and 2, measure the pH change of the sample solution while adding a 0.1 mol / L sodium hydroxide aqueous solution dropwise at a rate of 0.01 mL / min. Record the volume (L) of sodium hydroxide aqueous solution added when the pH reaches 9.0. From the following formula, 1 nm 2 Si-OH content per unit Sn (particles / nm) 2 It is possible to calculate ). Sn = {(ab) × c × NA} / (d × e) a: NaOH titration volume (L) of sample solution 2 b: Volume of NaOH titration of sample solution 1 (L) c: Concentration of the NaOH solution used in the titration (mol / L) NA: Avogadro's number d: Mass of silica microparticles (g) e: BET specific surface area of ​​silica nanoparticles (nm) 2 / g: Specific surface area (m²) obtained above 2 (converted from / g)

[0100] <Method for calculating the coverage ratio (Ssi) of toner particles by silica microparticles on the surface of toner particles> The coverage rate (Ssi) of silica microparticles on the surface of toner particles is calculated from backscattered electron images obtained by scanning electron microscopy (SEM). Backscattered electron images are also called "compositional images," and particles with smaller atomic numbers appear darker, while those with larger atomic numbers appear brighter. Backscattered electron images of toner are obtained under the following observation conditions. The method for obtaining backscattered electron images of toner and the method for calculating the coverage rate of silica microparticles on the surface of toner particles are described below.

[0101] <Method for obtaining backscattered electron images of toner> Equipment used: ULTRA PLUS manufactured by Carl Zeiss Microscopy Co., Ltd. Acceleration voltage: 1.0kV WD: 2.5mm Aperture Size: 30.0 μm Detection signal: EsB (Energy-selective backscattered electrons) EsB Grid: 700V Observation magnification: 20,000x Contrast: 63.0 ± 5.0% (reference value) Brightness: 38.0 ± 5.0% (reference value) Resolution: 1024 x 768 pixels Pre-treatment: Toner is sprayed onto carbon tape (Pt deposition is not performed). Contrast and brightness should be set appropriately according to the condition of the equipment being used. The acceleration voltage and EsB grid should be set to achieve objectives such as acquiring structural information of the toner's outermost surface, preventing charge-up of undeposited samples, and selectively detecting high-energy backscattered electrons. The observation field should be selected to cover areas with low toner curvature.

[0102] <Method for calculating the silica coating rate of toner> The silica coverage is obtained by analyzing the backscattered electron image of the toner surface obtained by the above method using the image processing software ImageJ (developed by Wayne Rashand). The procedure is as follows. First, convert the backscattered electron image to 8-bit using the Image menu's Type option. Next, reduce image noise by setting the Median diameter to 2.0 pixels using the Process menu's Filters option. Then, select the entire backscattered electron image using the Rectangle Tool on the toolbar. Subsequently, select Threshold from the Image menu's Adjust option and specify a luminance threshold (85-128 (256 gradations, reference value)) so that only luminance pixels originating from silica nanoparticles within the backscattered electrons are selected. Finally, select Measure from the Analyze menu to calculate the area percentage (area %) of the selected luminance portion in the backscattered electron image. The above procedure is performed for 20 fields of view for the toner to be evaluated, and the arithmetic mean is defined as the coverage rate (Ssi) of silica microparticles on the surface of the toner particles.

[0103] <Confirmation of the presence of magnetic material on the surface of toner particles and method for calculating the magnetic material abundance Sm> The prevalence of magnetic material on the surface of toner particles is calculated by observing the surface of toner particles obtained by the separation operation of silica nanoparticles and toner particles described above using a low-acceleration voltage scanning electron microscope (SEM). When the surface of toner particles is observed using a SEM at a low acceleration voltage of 1 kV or less, the electron beam penetration depth is in the range of several tens of nanometers, thus providing information about the vicinity of the toner particle surface. When observed with a backscattered electron detector, a contrast according to atomic weight is obtained, resulting in a clear contrast between the resin portion (derived from C atoms) that makes up the toner and the magnetic material (derived from Fe atoms) present on the surface of the toner particles. To determine whether or not magnetic material is present on the surface of the toner particles, elemental mapping using SEM-EDX is used. If Fe is detected in the area where contrast is obtained between the resin portion and the magnetic material through the above procedure, it is determined that magnetic material is present on the surface of the toner particles. The following describes in detail the method for acquiring backscattered electron images of toner particles using a low-acceleration voltage SEM.

[0104] (Method for acquiring backscattered electron images of toner particles using low-acceleration voltage SEM) Equipment used: ULTRA PLUS manufactured by Carl Zeiss Microscopy Co., Ltd. Acceleration voltage: 1.0kV WD: 2.5mm Aperture Size: 30.0 μm Detection signal: EsB (Energy-selective backscattered electrons) EsB Grid: 700V Observation magnification: 20,000x Contrast: 63.0 ± 5.0% (reference value) Brightness: 38.0 ± 5.0% (reference value) Resolution: 1024 x 768 pixels Pre-treatment: Toner particles are scattered onto carbon tape (Pt deposition is not performed). Contrast and brightness should be set appropriately according to the condition of the equipment being used. The acceleration voltage and EsB grid should be set to achieve objectives such as acquiring structural information of the toner's outermost surface, preventing charge-up of undeposited samples, and selectively detecting high-energy backscattered electrons. The observation field should be selected to cover areas with low toner curvature.

[0105] The prevalence of magnetic material on the surface of toner particles can be calculated as follows. (Method for calculating the abundance of magnetic material on the surface of toner particles) The abundance of magnetic material is obtained by analyzing the low-acceleration voltage SEM backscattered electron images of toner particles obtained using the above method, with the image processing software ImageJ (developed by Wayne Rashand). The procedure is as follows. First, convert the backscattered electron image to 8-bit using the Image menu's Type option. Next, reduce image noise by setting the Median diameter to 2.0 pixels using the Process menu's Filters option. Then, select the entire backscattered electron image using the Rectangle Tool on the toolbar. Subsequently, select Threshold from the Image menu's Adjust option and specify a luminance threshold (147-255 (256 gradations, reference value)) so that only the areas containing magnetic material within the backscattered electrons are selected. Finally, select Measure from the Analyze menu to calculate the area percentage (area %) of the selected luminance portion in the backscattered electron image. The above procedure is performed for 20 fields of view for each toner particle to be evaluated, and the arithmetic mean is taken as the abundance Sm of the magnetic material on the surface of the toner particle.

[0106] <Method for measuring the number-average particle size of primary silica microparticles> The number-average particle size of silica nanoparticles is measured from secondary electron images obtained by scanning electron microscopy (SEM) observation of the toner surface.

[0107] (Method for acquiring secondary electron images of toner) Equipment used: ULTRA PLUS manufactured by Carl Zeiss Microscopy Co., Ltd. Acceleration voltage: 1.0kV WD: 2.5mm Aperture Size: 30.0 μm Detection signal: SE2 (secondary electrons) Observation magnification: 50,000x Resolution: 1024 x 768 pixels Pre-treatment: Toner is sprayed onto carbon tape (Pt deposition is not performed). From the obtained secondary electron images, the longest diameter of 100 primary silica particles on the surface of the toner particles was measured, and the arithmetic mean was taken as the number-average particle size of the silica particles. The distinction between silica nanoparticles and strontium titanate nanoparticles is made by elemental mapping using SEM-EDX.

[0108] <Method for measuring the carbon content of silica microparticles> The amount of carbon (C) derived from the hydrophobic treatment agent for silica nanoparticles is from HORIBA's carbon... The measurement is performed using a sulfur analyzer (product name: EMIA-320). 0.3 g of silica nanoparticles, which are the sample, are accurately weighed and placed in the crucible for the carbon-sulfur analyzer described above. To this, 0.3 g ± 0.05 g of tin (replacement part number 9052012500) and 1.5 g ± 0.1 g of tungsten (replacement part number 9051104100) are added as combustion aids. Then, the silica nanoparticles are heated at 1100°C in an oxygen atmosphere according to the instruction manual provided with the carbon-sulfur analyzer described above. As a result, the hydrophobic groups derived from the hydrophobic treatment agent on the surface of the silica nanoparticles are thermally decomposed into CO2, and the amount of CO2 is measured. From the amount of CO2 obtained, the amount of carbon (mass %) contained in the silica nanoparticles is determined.

[0109] <Calculation of the carbon content immobilization rate of silica nanoparticles> (Washing with chloroform: Extraction of unimmobilized treatment agents) By using the method described above for separating silica microparticles from the toner surface, the silica microparticles separated from the toner can be used. Place 0.50 g of silica microparticles and 40 mL of chloroform in an Erlenmeyer flask, cover, and stir for 2 hours (magnetic stirrer, 300 rpm). Then, stop stirring and let stand for 12 hours. Next, centrifuge and remove all of the supernatant. Centrifugation is performed using a KOKUSAN centrifuge (product name: H-9R) with a Bn1 rotor and a Bn1 rotor-compatible poly centrifuge tube, at 20°C, 10000 rpm, and for 5 minutes.

[0110] The centrifuged silica nanoparticles are placed back into an Erlenmeyer flask, 40 mL of chloroform is added, and the flask is covered and stirred for 2 hours (magnetic stirrer, 300 rpm). After that, stirring is stopped and the flask is allowed to stand for 12 hours. Next, the supernatant is removed by centrifugation. This procedure is repeated two more times. The resulting sample is then dried in a constant temperature bath at 50°C for 2 hours. The pressure is then reduced to 0.07 MPa and the sample is dried at 50°C for 24 hours to allow the chloroform to evaporate completely.

[0111] (C amount measurement) As described above, the carbon content of silica microparticles washed with chloroform and the carbon content of silica microparticles before washing with chloroform are measured according to the "Method for Measuring the Carbon Content of Silica Microparticles" described above. The carbon content immobilization rate of silica microparticles can be calculated using the following formula. C content immobilization rate [%] = (C content of silica microparticles treated with chloroform / C content of silica microparticles before washing with chloroform) × 100

[0112] <Method for measuring the ratio of the elemental strength of silica microparticles on the surface of toner particles to the strontium titanate microparticles> The ratio of the silica microparticle content to the strontium titanate microparticle content on the surface of toner particles, based on elemental intensity (Si / Sr), can be measured and calculated by X-ray fluorescence analysis (XRF). The toner is pelletized using the press molding method described below to obtain a sample, and the Si atoms contained in the silica microparticles and the Sr atoms specific to the strontium titanate microparticles are quantified using the wavelength-dispersive X-ray fluorescence analyzer shown below. (i) Examples of equipment used X-ray fluorescence analyzer 3080 (Rigaku Electric Co., Ltd.) (ii) Sample preparation Sample preparation is performed using a MAEKAWA Testing Machine (manufactured by MAYEKAWA MFG Co., LTD). 0.5g of toner is placed in an aluminum ring (model number: 3481E1), the load is set to 5.0 tons, and it is pressed for 1 minute to form pellets. (iii) Measurement conditions Measuring diameter: 10φ Measurement potential, voltage: 50kV, 50~70mA 2θ angle 25.12° Crystal plate LiF Measurement time: 60 seconds (iv) Calculation of the Si element intensity ratio corresponding to the Si atoms contained in silica nanoparticles To calculate the proportion of the Si element intensity of the toner being analyzed that corresponds to the Si atoms contained in the silica microparticles, the same measurement is performed on toner particles separated from the surface of the toner using the method described above. From the Si element intensity obtained from the measurement before silica separation and the Si element intensity after silica separation, the Si element intensity corresponding to the Si atoms contained in the silica microparticles can be calculated based on the following formula. (Si element intensity ratio corresponding to Si atoms contained in silica nanoparticles) = (Si element intensity before silica separation - Si element intensity after silica separation) / (Si element intensity before silica separation) (v) Calculation of Si / Sr Si / Sr = (Si elemental strength before silica separation × Si elemental strength ratio corresponding to Si atoms contained in silica nanoparticles / Sr elemental strength before silica separation)

[0113] <Measurement of Si content and remanent magnetization (σr) in magnetic materials> The Si content and remanent magnetization (σr) in a magnetic material are measured as follows. The silica on the toner surface is separated using the method described above to obtain toner particles. The toner particles are dissolved in chloroform, and the magnetic material is recovered using a magnet. The recovered magnetic material is immersed in chloroform and recovered with a magnet, and this process is repeated three times to wash the magnetic material. 200 mg of the obtained magnetic material is placed in a liquid sample measuring cup for X-ray fluorescence measurement and spread uniformly across the entire bottom surface. The Si content in the magnetic material is quantified using the fundamental parameter method with the X-ray fluorescence analyzer Axios (PANalytical) and its accompanying dedicated analysis software "SuperQ ver.4.0F" (PANalytical). The measurement is performed under a He atmosphere and at an output of 2.4 kW, and the elements to be measured range from Na (atomic number 11) to U (atomic number 92). Furthermore, the σr of the magnetic iron oxide particles in the obtained magnetic material was measured using a vibrating magnetometer VSMP-1-10 (manufactured by Toei Kogyo Co., Ltd.) at room temperature of 25°C with an external magnetic field of 795.8 kA / m and a magnetic field sweep rate of 1.6 kA / m / s.

[0114] <Measurement of magnetic material content> The silica on the toner surface is separated using the method described above to obtain toner particles. The mass of the obtained toner particles is measured. Furthermore, a magnetic material is obtained from the toner particles using the method described above, and the mass of the obtained magnetic material is measured. From the mass of the toner particles and the mass of the magnetic material obtained in this way, the content of the magnetic material per 100 parts by mass of toner particles is determined.

[0115] <Method for measuring the weight-average particle size (D4) of toner> The weight-average particle size (D4) of the toner is measured using the Coulter Multisizer, a precision particle size distribution analyzer with a pore electrical resistance method equipped with a 100 μm aperture tube. Using the "Beckman Coulter Multisizer 3" (registered trademark, manufactured by Beckman Coulter) and the accompanying dedicated software "Beckman Coulter Multisizer 3 Version 3.51" (manufactured by Beckman Coulter) for setting measurement conditions and analyzing measurement data, measurements are taken with an effective number of measurement channels of 25,000, and the measurement data is analyzed and calculated. The electrolytic aqueous solution used for measurement is prepared by dissolving special grade sodium chloride in deionized water to a concentration of approximately 1% by mass; for example, "ISOTON II" (manufactured by Beckman Coulter) can be used. Before performing measurements and analysis, configure the dedicated software as follows. In the dedicated software's "Change Standard Measurement Method (SOM)" screen, set the total count in control mode to 50,000 particles, the number of measurements to 1, and the Kd value to "Standard particle 10.0 Set the value obtained using the "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 the "Flush aperture tube after measurement" option. In the dedicated software's "Pulse to Particle Size Conversion Settings Screen," set the bin spacing to logarithmic particle size, the particle size bins to 256 particle size bins, and the particle size range to 2 μm or more and 60 μm or less.

[0116] The specific measurement method is as follows: (1) Pour approximately 200 ml of the electrolytic solution into a 250 ml round-bottom glass beaker specifically designed for the Multisizer 3, set it on the sample stand, and stir the mixture with the stirrer rod at 24 revolutions per second in a counterclockwise direction. Then, use the "Aperture Tube Flash" function of the dedicated software to remove any dirt and air bubbles from inside the aperture tube. (2) Place approximately 30 ml of the electrolytic aqueous solution into a 100 ml flat-bottomed glass beaker, and add approximately 0.3 ml of a diluted solution of "Contaminon N" (a 10% by mass aqueous solution of a pH 7 neutral detergent for cleaning precision measuring instruments, consisting of a nonionic surfactant, anionic surfactant, and organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) diluted three times by mass with deionized water as a dispersant. (3) Two oscillators with an oscillation frequency of 50 kHz are built in with their phases shifted by 180 degrees, and a predetermined amount of deionized water is placed in the water tank of an ultrasonic dispersion device called "Ultrasonic Dispersion System Tetora150" (manufactured by Nikko Bios Co., Ltd.) with an electrical output of 120 W. Approximately 2 ml of the aforementioned Contaminon N is added to this water tank. (4) Place the beaker from (2) into the beaker fixing hole of the ultrasonic disperser and operate the ultrasonic disperser. Then, adjust the height of the beaker so that the resonance state of the liquid surface of the electrolytic aqueous solution inside the beaker is maximized. (5) While irradiating the electrolytic aqueous solution in the beaker described in (4) with ultrasound, add approximately 10 mg of toner to the electrolytic aqueous solution in small amounts and disperse it. Continue the ultrasonic dispersion treatment for another 60 seconds. During ultrasonic dispersion, adjust the water temperature in the tank to be between 10°C and 40°C as appropriate. (6) Using a pipette, the electrolytic aqueous solution (5) containing the dispersed toner is dropped into the round-bottom beaker (1) placed in the sample stand, and the concentration is adjusted to approximately 5%. The measurement is then continued until the number of particles measured reaches 50,000. (7) The measurement data is analyzed using the dedicated software attached to the device, and the weight-average particle size (D4) is calculated. Note that the "Average Diameter" on the Analysis / Volume Statistics (Arithmetic Mean) screen when the dedicated software is set to Graph / Volume % is the weight-average particle size (D4). [Examples]

[0117] The present disclosure will be further described below with reference to manufacturing examples and embodiments, but these are not intended to limit the present disclosure in any way. All parts in the following formulations are in parts by mass.

[0118] <Example of manufacturing silica nanoparticle 1> Untreated dry silica as small-particle inorganic fine particles (number-average particle size of primary particles: 15 nm, BET specific surface area: 200 m²) 2 ( / g) and untreated dry silica as large-particle inorganic fine particles (number average particle size of primary particles 35 nm, BET specific surface area 50 m²) 2 The material ( / g) was added in a mass ratio of 10:1 and heated to 330°C while being stirred to a fluid state. The reactor was sealed by purging the inside with nitrogen gas, and octamethylcyclotetrasiloxane was sprayed using a spray nozzle as the first surface treatment agent until the gauge pressure reached 200 kPa, and then mixed. After that, heating and stirring were continued for 1 hour to allow the reaction to proceed and complete the coating treatment. After the treatment, the reaction system was replaced with a nitrogen atmosphere and heated again to 330°C. Subsequently, as a second surface treatment agent, 10 parts of dimethyl silicone oil (Shin-Etsu Chemical Co., Ltd. KF-96-50CS) was sprayed onto 100 parts of untreated dry silica, and a similar coating treatment was carried out for 1 hour to obtain silica fine particles 1. The physical properties of silica fine particles 1 are shown in Table 1-2.

[0119] <Manufacturing examples of silica microparticles 2-6> Silica nanoparticles 2-6 were obtained in the same manner as in the production example of silica nanoparticle 1, except that the reaction time of the first surface treatment agent and the amount of the second surface treatment agent were changed as shown in Table 1-1. The physical properties of silica nanoparticles 2-6 are shown in Table 1-2. Table 1-1 shows the structure of the substituents of the compound represented by formula (3).

[0120] <Manufacturing example of silica microparticles 7> Untreated dry silica as small-particle inorganic fine particles (number-average particle size of primary particles: 15 nm, BET specific surface area: 200 m²) 2 ( / g) and untreated dry silica as large-particle inorganic fine particles (number average particle size of primary particles 35 nm, BET specific surface area 50 m²) 2 Silica nanoparticles 7 were obtained in the same manner as in the production example of silica nanoparticle 1, except that the amount of silica nanoparticles ( / g) was added in a mass ratio of 6:1. The physical properties of silica nanoparticles 7 are shown in Table 1-2.

[0121] <Example of manufacturing silica microparticles 8> Untreated dry silica as inorganic fine particles (number-average particle size of primary particles 15 nm, BET specific surface area 200 m²) 2 Silica nanoparticles 8 were obtained in the same manner as in the manufacturing example of silica nanoparticle 1, except that only ( / g) was added. The physical properties of silica nanoparticles 8 are shown in Table 1-2.

[0122] <Manufacturing examples of silica microparticles 9-15> Silica nanoparticles 9 to 15 were obtained in the same manner as the production example of silica nanoparticle 1, except that the second surface treatment agent was a carbinol-modified silicone oil (KF-6002, manufactured by Shin-Etsu Chemical Co., Ltd.), and the BET specific surface area of ​​the untreated dry silica to be added, the reaction time of the first surface treatment agent, and the amount of the second surface treatment agent were changed as shown in Table 1-1. The physical properties of silica nanoparticles 9 to 15 are shown in Table 1-2.

[0123] <Example of manufacturing silica microparticles 16> Untreated dry silica as inorganic fine particles (number-average particle size of primary particles 15 nm, BET specific surface area 200 m²) 2 The mixture ( / g) was added and heated to 290°C while being stirred to a fluid state. The reactor was sealed by purging the inside with nitrogen gas, and octamethylcyclotetrasiloxane was sprayed using a spray nozzle as the first surface treatment agent until the gauge pressure reached 100 kPa, and then mixed. After that, heating and stirring were continued for 1 hour to allow the reaction to complete the coating treatment. After the treatment, the reaction system was replaced with a nitrogen atmosphere and heated again to 290°C. Subsequently, as a second surface treatment agent, 15 parts of dimethyl silicone oil (Shin-Etsu Chemical Co., Ltd. KF-96-50CS) was sprayed onto 100 parts of untreated dry silica, and a similar coating treatment was carried out for 1 hour to obtain silica fine particles 16. The physical properties of the silica fine particles 16 are shown in Table 1-2.

[0124] <Example of manufacturing silica microparticles 17> Untreated dry silica as inorganic fine particles (number-average particle size of primary particles 15 nm, BET specific surface area 200 m²) 2( / g) was charged and heated to 250°C in a fluidized state by stirring. The inside of the reactor was purged with nitrogen gas and the reactor was sealed. Using a spray nozzle, octamethylcyclotetrasiloxane was sprayed and mixed as the first surface treatment agent until the gauge pressure reached 100 kPa. Thereafter, heating and stirring were continued for 1 hour to carry out a coating treatment, and silica fine particles 17 were obtained. The physical property values of the silica fine particles 17 are shown in Table 1-2.

[0125] <Production Example of Silica Fine Particles 18> As the inorganic fine particles, untreated dry silica (number average particle diameter of primary particles: 15 nm, BET specific surface area: 200 m 2 ( / g) was charged and heated to 250°C in a fluidized state by stirring. The inside of the reactor was purged with nitrogen gas and the reactor was sealed. While continuing stirring and heat preservation to maintain the fluidized state of silica, 30 parts of dimethyl silicone oil (KF-96-50CS manufactured by Shin-Etsu Chemical Co., Ltd.) was spray-treated with respect to 100 parts of untreated dry silica, and a coating treatment was carried out for 1 hour to obtain silica fine particles 18. The physical property values of the silica fine particles 18 are shown in Table 1-2.

[0126] <Production Examples of Silica Fine Particles 19 to 20> Silica fine particles 19 to 20 were obtained in the same manner as in the production example of silica fine particles 18, except that the number of parts of dimethyl silicone oil and the treatment temperature were changed as shown in Table 1-1. The physical property values of the silica fine particles 19 to 20 are shown in Table 1-2.

[0127] <Production Example of Silica Fine Particles 21> As the inorganic fine particles, untreated dry silica (number average particle diameter of primary particles: 15 nm, BET specific surface area: 200 m 2 ( / g) was charged and heated to 250°C in a fluidized state by stirring. The inside of the reactor was purged with nitrogen gas and the reactor was sealed. Using a spray nozzle, 25 parts of hexamethyldisilazane was sprayed as the first surface treatment agent. Thereafter, heating and stirring were continued for 1 hour to carry out a coating treatment. After the treatment, the atmosphere inside the reaction system was replaced with a nitrogen atmosphere, and it was heated again to 250°C. Subsequently, as the second surface treatment agent, 10 parts of dimethyl silicone oil (KF-96-50CS manufactured by Shin-Etsu Chemical Co., Ltd.) was spray-treated with respect to 100 parts of untreated dry silica, and further coating treatment was similarly carried out for 1 hour to obtain silica fine particles 21. The physical property values of the silica fine particles 21 are shown in Table 1-2.

[0128] <Production Example of Silica Fine Particles 22> Untreated dry silica (number average particle diameter of primary particles: 15 nm, BET specific surface area: 200 m 2 / g) as the inorganic fine particles was charged and heated to 250°C in a fluidized state by stirring. The inside of the reactor was replaced with nitrogen gas and the reactor was sealed, and 25 parts of hexamethyldisilazane was sprayed as the first surface treatment agent with respect to 100 parts of untreated dry silica using a spray nozzle. Then, coating treatment was carried out by continuing heating and stirring for 1 hour to react, and silica fine particles 22 were obtained. The physical property values of the silica fine particles 22 are shown in Table 1-2.

[0129] <Production Example of Magnetic Substance 1> Into an aqueous solution of ferrous sulfate, a caustic soda solution of 1.05 equivalents with respect to the iron element, P2O5 in an amount of 0.15 mass% in terms of phosphorus element with respect to the iron element, and SiO2 in an amount of 1.00 mass% in terms of silicon element with respect to the iron element were mixed to prepare an aqueous solution containing ferrous hydroxide. The pH of the aqueous solution was adjusted to 8.0, and an oxidation reaction was carried out at 85°C while blowing air to prepare a slurry liquid having seed crystals. Next, an aqueous solution of ferrous sulfate was added to this slurry liquid so as to be 1.05 equivalents with respect to the initial alkali amount (sodium component of caustic soda), and then the slurry liquid was maintained at pH 7.6 and an oxidation reaction was carried out while blowing air to obtain a slurry liquid containing magnetic iron oxide particles. The generated magnetic iron oxide particles were filtered with a filter press, washed with a large amount of water, dried at 120°C for 2 hours, and the obtained particles were crushed to obtain magnetic substance 1 having a number average particle diameter of 150 nm. The physical properties of magnetic substance 1 are shown in Table 2.

[0130] <Production Examples of Magnetic Substances 2 to 5, 7 to 11> In the example of producing magnetic material 1, magnetic materials 2-5 and 7-11 were obtained in the same manner as in the example of producing magnetic material 1, except that the amount of SiO2 mixed was adjusted so that the Si content was the value shown in Table 2, and the amount of air blown in and the oxidation reaction time were adjusted so that the number-average particle size was the value shown in Table 2. The physical properties of magnetic materials 2-5 and 7-11 are shown in Table 2.

[0131] <Example of manufacturing magnetic material 6> Magnetic material 4 was dispersed again in water, and sodium silicate was added to the resulting slurry at a concentration of 0.20% by mass (silicon equivalent) per 100 parts of magnetic particles. Then, the pH of the slurry was adjusted to 6.0, and the mixture was stirred to obtain magnetic material 6. The physical properties of magnetic material 6 are shown in Table 2.

[0132] <Example of toner particle 1 manufacturing> [Example of toner manufacturing using the pulverization method] • Binding resin 100.0 parts (Amorphous PES resin. An amorphous polyester resin obtained by the condensation reaction of ethylene oxide and propylene oxide adducts of bisphenol A with terephthalic acid; Mw=9500, Tg=58℃) ·Magnetic material 1 80.0 parts • Hydrocarbon wax 5.0 parts (Fischer-Tropsch wax, melting point 77°C) • Charge control agent 1.0 part (T-77: Manufactured by Hodogaya Chemical Industry Co., Ltd.) After pre-mixing the above materials in an FM mixer (manufactured by Nippon Coke Industries Co., Ltd.), the mixture is rotated at 3.33 seconds. -1 The mixture was kneaded using a twin-screw extruder (PCM-30 model, manufactured by Ikegai Iron Works Co., Ltd.) with the temperature adjusted so that the temperature of the mixture near the outlet was 120°C. The resulting mixture was cooled, coarsely ground in a hammer mill, and then ground in a mechanical pulverizer (T-250 model, manufactured by Turbo Industries Co., Ltd.). The resulting finely ground powder was classified using a multi-part classifier utilizing the Coanda effect. As a result, toner particles 1 with a weight-average particle size (D4) of 7.0 μm were obtained. Magnetic material was present on the surface of toner particles 1.

[0133] <Manufacturing examples of toner particles 2-12, 15, 17, and 18> Except for changing the amount and type of magnetic material added to the conditions shown in Table 3, the same procedure as for manufacturing toner particle 1 was performed to obtain toner particles 2-12, 15, 17, and 18. Magnetic material was present on the surface of toner particles 2-12, 15, 17, and 18.

[0134] <Example of toner particle 13 manufacturing> Except for changing the binder resin to a styrene / n-butyl acrylate copolymer (styrene-acrylic resin with a mass ratio of styrene to n-butyl acrylate of 78:22; Mw=8500, Tg=58℃), the same procedure as for the production of toner particle 1 was performed to obtain toner particle 13. A magnetic material was present on the surface of toner particle 13.

[0135] <Example of toner particle 14 manufacturing> [Example of toner manufacturing using suspension polymerization] 720 parts of deionized water were mixed with 450 parts of a 0.1 mol / L Na3PO4 aqueous solution, heated to 60°C, and then 67.7 parts of a 1.0 mol / L CaCl2 aqueous solution were added to obtain an aqueous medium containing a dispersion stabilizer. • Styrene 78.00 parts n-butyl acrylate 22.00 parts • Polypropylene glycol #400 diacrylate (APG400) 1.70 parts ·Magnetic material 1 79.00 parts The above formulation was uniformly dispersed and mixed using an attritor (Nippon Coke Industries Co., Ltd.). The obtained monomer composition was heated to 60°C, and the following materials were mixed and dissolved therein to obtain a polymerizable monomer composition. • Hydrocarbon wax 5.0 parts (Fischer-Tropsch wax, melting point 77°C) • Charge control agent 1.0 part (T-77: Manufactured by Hodogaya Chemical Industry Co., Ltd.) • Polymerization initiator 10.00 parts (t-butyl peroxypivalate (25% toluene solution)) A polymerizable monomer composition was introduced into an aqueous medium and stirred at 12,000 rpm for 15 minutes using a TK type homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) at a temperature of 60°C under a nitrogen atmosphere, followed by granulation. Thereafter, stirring was carried out with a paddle stirring blade, and a polymerization reaction was conducted at a reaction temperature of 70°C for 300 minutes. After completion of the reaction, the temperature of the suspension was raised to 100°C and held for 2 hours. Thereafter, as a cooling step, water at 0°C was introduced into the suspension, and the suspension was cooled from 98°C to 30°C at a rate of 200°C / min, then heated again and held at 55°C for 3 hours. Thereafter, it was naturally cooled to room temperature at 25°C. The cooling rate at that time was 2°C / min. Thereafter, hydrochloric acid was added to the suspension and thoroughly washed to dissolve the dispersion stabilizer, followed by filtration and drying to obtain toner particles 14 having a weight average particle diameter (D4) of 7.3 μm. There was no magnetic substance on the surface of the toner particles 14.

[0136] <Production Example of Toner Particles 16> Toner particles 16 were obtained by carrying out the same processing operations as the production method of toner particles 14, except that magnetic substance 1 was changed to magnetic substance 7 and the number of magnetic substance parts was set to 80.0 parts. There was no magnetic substance on the surface of the toner particles 16.

[0137] <Production Example of Toner 1> Using an FM mixer (manufactured by Nippon Coke & Engineering Co., Ltd., "FM-10B"), under the condition of a rotation speed of 3200 rpm, 100 parts of toner particles 1, 1.2 parts of silica fine particles, and 0.17 parts of strontium titanate fine particles (number average particle diameter 1.2 μm) were put in and mixed for 180 seconds to obtain a toner mixture. Thereafter, coarse particles were removed using a 300-mesh (opening size 48 μm) sieve to obtain toner 1.

[0138] <Production Examples of Toner 2, 4 to 45> Toners 2, 4 to 45 were obtained by carrying out the same operations as the production example of toner 1, except that the types of toner particles and silica fine particles, the added number of silica fine particles, and the added number of strontium titanate fine particles were changed as shown in Table 3.

[0139] <Example of Toner 3 production> Using an FM mixer (FM-10B manufactured by Nippon Coke Industries Co., Ltd.), 14 parts toner particles and 1 part magnetic material were added and mixed for 180 seconds at a rotation speed of 3500 rpm. Then, 1.1.2 parts silica fine particles and 0.17 parts strontium titanate fine particles (number-average particle size 1.2 μm) were added and mixed for 180 seconds at a rotation speed of 3200 rpm to obtain a toner mixture. Subsequently, coarse particles were removed using a 300-mesh sieve (mesh opening 48 μm) to obtain toner 3.

[0140] <Example 1> The following evaluation was performed on Toner 1. For the evaluation, we used an HP LaserJet Enterprise M609dn with a modified process speed of 410 mm / sec. The evaluation paper used was Vitality (manufactured by Xerox, basis weight 75 g / cm²). 2 (Letter size) was used.

[0141] <Evaluation of charge retention and charge rise time> The above-mentioned image rendering test machine and evaluation toner were filled in a high-temperature, high-humidity environment of 32.5℃ / 80%RH. After leaving the toner cartridge unused for more than a day, 1000 sheets of a horizontal line pattern, consisting of 4-dot horizontal lines spaced 176 dots apart, were printed using the aforementioned print test machine. Subsequently, the cartridge was left unused in the same environment for 72 hours, and 100 sheets were printed. After printing 1000 pages, after leaving the cartridge for 72 hours, and after printing 100 pages after the waiting period, the charge level (μC / g) of the toner on the developer carrier inside the toner cartridge was measured using a blow-off powder charge level measuring device TB-200 (manufactured by Toshiba Chemical Co., Ltd.) to evaluate the charge retention and charge rise performance under high temperature and high humidity conditions. The smaller the rate of decrease in charge after 72 hours of storage, the better the toner's charge retention. Furthermore, a toner with a higher ratio of charge level after 100 prints (after being left idle) to charge level after 1000 prints indicates better charge build-up performance. The following criteria were established for evaluating charge retention and charge build-up performance. [Evaluation Criteria] (Static resistance) (Charge amount after 72 hours of inactivity) / (Charge amount after printing 1000 sheets) × 100 A: Over 90% B: 85% or more, less than 90% C: 80% to less than 85% D: 75% or more but less than 80% E: Less than 75% (Static charge rise) (Charge level after 100 prints after leaving it idle) / (Charge level after 1000 prints) × 100 = A: 95% or higher B: 90% or more but less than 95% C: 85% to less than 90% D: 80% or more but less than 85% E: Less than 80%

[0142] <Evaluation of image density when left in a high-temperature, high-humidity environment> After leaving the above-mentioned print test machine and toner cartridge filled with evaluation toner in a high-temperature, high-humidity environment of 32.5℃ / 80%RH for more than one day, 10,000 sheets of a horizontal line pattern, in which 4-dot horizontal lines were printed at 176-dot intervals, were printed using the print test machine. Subsequently, the equipment was left in the same environment for 72 hours. After being left for 72 hours, a solid black image was formed, and the density of this solid black image was measured using a Macbeth RD918 reflectance densitometer (Macbeth Corporation). The evaluation criteria for image density when left in a high-temperature, high-humidity environment are as follows. [Evaluation Criteria] A: 1.35 or higher B: 1.30 or higher and less than 1.35 C: 1.25 or higher and less than 1.30 C-: 1.20 or higher and less than 1.25 D: 1.15 or higher and less than 1.20 E: Less than 1.15

[0143] <Transcriptional evaluation> After leaving the above-mentioned print test machine and toner cartridge filled with evaluation toner in a low-temperature, low-humidity environment of 15.0℃ / 10%RH for more than one day, 1000 sheets of a horizontal line pattern, in which 4-dot horizontal lines were printed at 176-dot intervals, were printed using the above-mentioned print test machine. Subsequently, the image forming apparatus was forcibly stopped during the solid image formation process, and the remaining toner on the photoreceptor was taped off with Mylar tape. Then, the density of the paper with only the Mylar tape attached was compared to the density of the paper with only the Mylar tape attached. The values ​​were subtracted and measured at 5 points, and the average value was calculated. The concentration was measured using a Macbeth reflectance densitometer RD918 (Macbeth Corporation). Transferability was evaluated according to the following criteria. [Evaluation Criteria] A: Less than 0.05 B: 0.05 or higher, less than 0.10 C: 0.10 or higher, less than 0.20 D:0.20 or more

[0144] <Developing material contamination evaluation> After leaving the above-mentioned print test machine and toner cartridge filled with evaluation toner in a high-temperature, high-humidity environment of 32.5℃ / 80%RH for more than one day, 10,000 sheets of a horizontal line pattern, in which 4-dot horizontal lines were printed at 176-dot intervals, were printed using the above-mentioned print test machine. Subsequently, the developing roller and the output halftone image were checked for the presence of vertical streaks, and material contamination was evaluated according to the following evaluation criteria. [Evaluation Criteria] A: No vertical streaks in the paper output direction are visible on the developing roller or on the image. B: Thin streaks are visible around the developing roller, and five or fewer vertical streaks are visible in the paper output direction on the image. C: Thin circumferential streaks are visible on the developing roller, and 5 to 9 vertical streaks in the paper output direction are visible on the image. D: Thin circumferential streaks are visible on the developing roller, and between 10 and 19 vertical streaks in the paper output direction are visible on the image. E: Fine circumferential streaks are visible on the developing roller, and more than 20 vertical streaks in the paper output direction are visible on the image.

[0145] <Evaluation of Cleanability> After leaving the above-mentioned print test machine and toner cartridge filled with evaluation toner in an extremely low temperature environment of 0°C / 30%RH for more than one day, a horizontal line pattern was printed using the above-mentioned print test machine, with 4-dot horizontal lines printed at 176-dot intervals, up to a maximum of 10,000 sheets, until vertical streaks appeared at the edges of the image due to cleaning failure. The cleaning performance was evaluated using the following criteria. [Evaluation Criteria] A: Even after printing 10,000 pages, no cleaning failures occur. B: The number of images processed before the first occurrence of vertical streaks due to cleaning failure was between 7,000 and 10,000. C: The number of images processed before the first occurrence of vertical streaks due to cleaning failure was between 4,000 and 7,000. D: The number of images processed before the first occurrence of vertical streaks due to cleaning failure was between 1,000 and 4,000. E: The number of images processed before the first vertical streaks due to cleaning failure occurred was less than 1,000.

[0146] <Evaluation of low-temperature fixation ability> The low-temperature fixing performance test used an external fuser, which was modified by removing the fuser unit from the above-mentioned printing test machine, allowing the fuser temperature to be arbitrarily set, and setting the process speed to 410 mm / sec. After leaving the above-mentioned printing test machine and a toner cartridge filled with evaluation toner in a high-temperature, high-humidity environment of 25°C / 50%RH for more than one day, the amount of toner applied per unit area was measured using the above-mentioned printing test machine to be 0.5 mg / cm². 2 The unfixed solid black image, which was set to a specific temperature, was output and passed through a fuser that was temperature-controlled to the set temperature. The resulting fixed image was fixed at 4.9 kPa (50 g / cm²). 2 ) 5 passes with a load of ) on a piece of Silbon paper The fixing temperature was defined as the temperature at which the concentration reduction rate before and after the rub test was 10% or less. Concentration measurements were performed using a Macbeth reflectance densitometer RD918 (Macbeth Corporation). The low-temperature fixation properties were evaluated using the following criteria. [Evaluation Criteria] A: Fixing temperature is less than 220°C B: Fixing temperature is 220°C or higher but less than 230°C C: Fixing temperature is between 230°C and 240°C D: Fixing temperature is 240°C or higher

[0147] <Examples 2-37> The evaluation was carried out in the same manner as in Example 1, except that toners 2-35, 44, and 45 were used.

[0148] <Comparative Examples 1-8> The evaluation was carried out in the same manner as in Example 1, except that toners 36-43 were used.

[0149] [Table 1-1] In Table 1-1, for silica nanoparticles 1-7, the substrate BET / m 2 The / g column shows the BET specific surface area of ​​200m². 2 / g small particle size silica microparticles and 50m 2 Large particle size silica nanoparticles / g, small particle size This indicates that the silica particles used were in a mass ratio of 10:1 (6:1 for silica fine particles 7). Regarding the quantity, hexamethyldisilazane (HMDS) is indicated by parts.

[0150] [Table 1-2] In Table 1-2, Sn represents {(ab)×c×NA} / (d×e), and B is the specific surface area (m²) of the silica nanoparticles. 2 The values ​​( / g) indicate the solid silica particles. Before washing, D / S / B represent the solid silica particles. 29The ratio (D / S) / B obtained from the Si-NMR DD / MAS method is shown. The post-wash D / S / B value is the ratio (D / S) / B value after washing the silica nanoparticles with chloroform. The C content represents the carbon content, and the number-average particle size represents the number-average particle size of the primary particles of the silica nanoparticles.

[0151] [Table 2] In the table, the Si quantity indicates the Si content in the magnetic material present on the surface of the toner particles, and σr indicates the remanent magnetization.

[0152] [Table 3] In the table, Ssi indicates the coverage rate of silica nanoparticles on the surface of toner particles, *1 indicates the presence or absence of fragment ions in formula (1), Sm indicates the abundance of magnetic material on the surface of toner particles, Si / Sr indicates the ratio of the silica nanoparticle content to the strontium titanate nanoparticle content based on elemental intensity, as determined by X-ray fluorescence analysis in the toner, and Msi / (D / S) / B indicates the ratio of the Si content in the magnetic material present on the surface of toner particles to (D / S) / B.

[0153] [Table 4]

[0154] This disclosure relates to the following configuration. (Composition 1) A toner containing magnetic material toner particles and silica fine particles on the surface of said toner particles, In time-of-flight secondary ion mass spectrometry measurements of the silica nanoparticles, fragment ions corresponding to the structure shown in equation (1) below were observed. [ka] In equation (1), n ​​represents an integer of 1 or greater, When 2.00 g of the silica fine particles were dispersed in a mixture of 25.0 g of ethanol and 75.0 g of a 20% by mass NaCl aqueous solution, and a titration was performed using sodium hydroxide, Sn, defined as Sn = {(ab) × c × NA} / (d × e), satisfies equation (2) below. 0.05 ≤ Sn ≤ 0.20 ···(2) In formula (2), a is the amount of NaOH titration (L) required to adjust the mixture containing the dispersed silica particles to pH 9.0. b is the amount of NaOH titration (L) required to adjust a mixture of 25.0 g of ethanol and 75.0 g of 20% by mass NaCl aqueous solution to pH 9.0. c is the concentration (mol / L) of the NaOH solution used in the titration. NA is Avogadro's number, d is the mass (g) of the silica fine particles, e is the BET specific surface area (nm) of the silica nanoparticles. 2 / g) is Solid silica fine particles 29 In the chemical shift obtained by the Si-NMR DD / MAS method, D is the area of ​​the peaks with peak tops in the range of -25 to -15 ppm, S is the sum of the areas of the M, D, T, and Q unit peaks in the range of -140 to 100 ppm, and B is the specific surface area of ​​the silica nanoparticles. 2 When we set it to / g, The ratio of (D / S) to B, (D / S) / B, is 5.7 × 10 -4 ~56×10 -4 And, The (D / S) / B value measured after washing the silica microparticles with chloroform was 1.7 × 10⁻⁶. -4 ~56×10 -4 And, In the chemical shift, when D1 is defined as the area of ​​the peaks where the peak top is located in the range between -19 ppm and -17 ppm, the ratio of D1 to D (D1 / D) is between 0.10 and 0.30. The magnetic material is present on the surface of the toner particles. A toner characterized by the following features. (Configuration 2) When the abundance of the magnetic material on the surface of the toner particles is denoted as Sm (area %), The toner according to configuration 1, wherein the Sm is 1.0 to 7.0 area percent. (Composition 3) The toner according to configuration 1 or 2, wherein the amount of the magnetic material is 30 to 120 parts by mass per 100 parts by mass of the toner particles. (Composition 4) When the coverage rate of the toner particles by the silica fine particles on the surface of the toner is calculated from the scanning electron microscope image of the toner surface, and this is expressed as Ssi (area %), The toner according to any of configurations 1 to 3, wherein the Ssi has an area of ​​30 to 90%. (Composition 5) Let Sm (area %) be the percentage of the magnetic material on the surface of the toner particles. When the coverage rate of the toner particles by the silica fine particles on the surface of the toner is calculated from the scanning electron microscope image of the toner surface, and this is expressed as Ssi (area %), A toner according to any of configurations 1 to 4, wherein the ratio of Sm to Ssi (Sm / Ssi) is between 0.010 and 0.240. (Composition 6) The toner according to any one of configurations 1 to 5, wherein the silica fine particles are surface-treated with at least the compound represented by the following formula (3). [ka] (In equation (3), R 1 , R 2 Each of these is independently a carbinol group, a hydroxyl group, an epoxy group, a carboxyl group, an alkyl group, or a hydrogen atom, and m is an integer from 1 to 200. (Composition 7) The toner according to any one of configurations 1 to 6, wherein the number-average particle size of the primary particles of the silica fine particles is 5 to 50 nm. (Composition 8) The toner according to any one of configurations 1 to 7, wherein the carbon content fixation rate when the silica fine particles are washed with chloroform is 30 to 70%. (Composition 9) The toner further contains strontium titanate fine particles on the surface of the toner particles, The toner according to any one of configurations 1 to 8, wherein the ratio of the silica fine particle content to the strontium titanate fine particle content (Si / Sr) based on elemental intensity, as determined by X-ray fluorescence analysis in the toner, is 0.10 to 1.50. (Composition 10) The toner according to any one of configurations 1 to 9, wherein the Si content in the magnetic material is 0.5 to 4.0% by mass. (Composition 11) The toner according to any one of configurations 1 to 10, wherein the silica fine particles are a silicone oil-treated product of silica fine particles treated with a cyclic siloxane.

Claims

1. A toner containing toner particles containing a magnetic material and silica fine particles on the surfaces of the toner particles, In measurement of the silica fine particles by time-of-flight secondary ion mass spectrometry, fragment ions corresponding to the structure represented by the following formula (1) were observed: In the formula (1), n ​​represents an integer of 1 or more, 2.00 g of the silica fine particles were dispersed in a mixed solution of 25.0 g of ethanol and 75.0 g of a 20% by mass aqueous solution of NaCl, and titration with sodium hydroxide was carried out. Sn defined as Sn={(a−b)×c×NA} / (d×e) satisfies the following formula (2): 0.05≦Sn≦0.20 (2) In the formula (2), a is the titer (L) of NaOH required to adjust the pH of the mixture in which the silica fine particles are dispersed to 9.0, b is the titer (L) of NaOH required to adjust a mixed solution of 25.0 g of ethanol and 75.0 g of a 20% by mass NaCl aqueous solution to pH 9.0, c is the concentration (mol / L) of the NaOH solution used in the titration, NA is Avogadro's number, d is the mass (g) of the silica fine particles, e is the BET specific surface area (nm ２ / g), The solid of the silica fine particles ２９ In the chemical shift obtained by Si-NMR DD / MAS method, the area of ​​the peak having a peak top in the range of −25 to −15 ppm is defined as D, The sum of the areas of the peaks of M units, D units, T units, and Q units present in the range of -140 to 100 ppm is defined as S, and the specific surface area of ​​the silica fine particles is defined as B (m ２ / g), The ratio of (D / S) to B (D / S) / B is 5.7 x 10 －４ ~56 x 10 －４ and The silica fine particles were washed with chloroform, and then the (D / S) / B ratio measured was 1.7×10 －４ ~56 x 10 －４ and When the area of ​​a peak having a peak top in the chemical shift range of more than −19 ppm to −17 ppm is defined as D1, the ratio of D1 to D (D1 / D) is 0.10 to 0.30, The magnetic material is present on the surface of the toner particles. A toner characterized by:

2. When the abundance ratio of the magnetic material on the surface of the toner particle is Sm (area %), 2. The toner according to claim 1, wherein the Sm is 1.0 to 7.0 area %.

3. The toner particles contain a binder resin, 3. The toner according to claim 1, wherein the content of the magnetic material is 30 to 120 parts by mass with respect to 100 parts by mass of the binder resin.

4. When the coverage rate of the silica fine particles on the surface of the toner particles calculated from an image of the toner surface observed by a scanning electron microscope is defined as Ssi (area %), 3. The toner according to claim 1, wherein the Ssi is 30 to 90 area %.

5. The proportion of the magnetic material on the surface of the toner particle is defined as Sm (area %), When the coverage rate of the silica fine particles on the surface of the toner particles calculated from an image of the toner surface observed by a scanning electron microscope is defined as Ssi (area %), 3. The toner according to claim 1, wherein the ratio of Sm to Ssi (Sm / Ssi) is from 0.010 to 0.

240.

6. 3. The toner according to claim 1, wherein the silica fine particles are surface-treated with at least a compound represented by the following formula (3): (R in formula (3) １ , R ２ are each independently a carbinol group, a hydroxy group, an epoxy group, a carboxy group, an alkyl group, or a hydrogen atom, and m is an integer of 1 to 200.

7. 3. The toner according to claim 1, wherein the number average particle size of the primary particles of the silica fine particles is 5 to 50 nm.

8. 3. The toner according to claim 1, wherein the silica fine particles have a carbon fixation rate of 30 to 70% when washed with chloroform.

9. the toner further contains strontium titanate fine particles on the surface of the toner particles, 3. The toner according to claim 1, wherein the ratio (Si / Sr) of the content of the silica fine particles to the content of the strontium titanate fine particles in the toner based on elemental intensity, as determined by fluorescent X-ray analysis, is 0.10 to 1.

50.

10. 3. The toner according to claim 1, wherein the content of Si in the magnetic material is 0.5 to 4.0% by mass.

11. 3. The toner according to claim 1, wherein the silica fine particles are silica fine particles treated with cyclic siloxane and then treated with silicone oil.

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