toner

Abstract

To provide a toner that suppresses an increase in liquid cross-linking force between the toner and a photoreceptor drum in a high temperature and high humidity environment, and has reduced the occurrence of transfer unevenness.SOLUTION: A toner contains a toner particle and silica fine particles. 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 specific mixed solution and a titration operation using NaOH is performed, a titration amount falls within a specific range. In solid 29Si-NMR measurement of the silica fine particles, when the area of a peak from -25 to -15 ppm is defined as D, the total sum of the areas of peaks from -140 to 100 ppm is defined as S, and the area of a peak exceeding -19 ppm and -17 ppm or less is defined as D1, the specific surface area of the silica fine particles, D, D1, and S satisfy a specific relationship. A specific polyvalent metal element is present in a specific amount on the surface of the toner particle.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] Electrophotography is a technology that forms an electrostatic latent image on a uniformly charged photoreceptor and visualizes the image information with charged toner, and is used in devices such as copiers and printers. In recent years, there has been a demand for longer lifespans and the ability to produce high-quality images regardless of the environment in order to accommodate the diverse uses of copiers and printers.

[0003] Patent Document 1 discloses a toner in which the amount of polyvalent metal elements is controlled to obtain excellent transferability. By suppressing fluctuations in the moisture content of the toner and improving the environmental stability of the toner charge amount, transfer dust and graininess in the image can be suppressed. Patent Document 2 discloses a toner in which spherical silica is externally added to toner particles containing a controlled amount of polyvalent metal elements in order to improve the charge buildup of the toner in a high-temperature, high-humidity environment. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-271394 [Patent Document 2] Japanese Patent Application Publication No. 2020-154294 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in a high-temperature, high-humidity environment, the toner of Patent Document 1 is prone to transfer defects (image unevenness caused by a local decrease in transfer efficiency during the transfer process) because the liquid bridging force between the toner and the photosensitive drum increases due to the influence of moisture present on the toner surface. Furthermore, although the toner of Patent Document 2 can suppress fogging in a high-temperature, high-humidity environment, the liquid bridging force between the toner and the photosensitive drum increases, causing transfer defects. For the above reasons, a toner is desired that can suppress an increase in the liquid bridging force between the toner and the photosensitive drum in a high-temperature, high-humidity environment and that causes less transfer roughness. The present disclosure provides a toner that suppresses an increase in the liquid bridging force between the toner and the photosensitive drum in a high-temperature, high-humidity environment, and that reduces the occurrence of transfer roughness. [Means for solving the problem]

[0006] The present disclosure provides a toner comprising toner particles 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: [ka] In the formula (1), n ​​represents an integer of 1 or more, When 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 mass % NaCl aqueous solution and titrated with sodium hydroxide, Sn, defined as Sn={(ab)×c×NA} / (d×e), satisfied 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 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 microparticles, 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, the area of ​​the peak whose top exists in the range of -25 to -15 ppm is defined as D, the sum of the areas of the peaks of M unit, D unit, T unit, and Q unit existing 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 5.7×10 -4 ~4.9×10 -3 and The silica particles were washed with chloroform and then measured for (D / S) / B of 1.7 x 10 -4 ~4.9×10 -3 and When the area of ​​the peak having a peak top in the range of more than -19 ppm and not more than -17 ppm in the chemical shift is defined as D1, The ratio of D1 to D (D1 / D) is 0.10 to 0.30, at least one polyvalent metal element selected from the group consisting of calcium, magnesium, aluminum, and iron is present on the surface of the toner particles; The toner has a total content of the polyvalent metal elements measured by the following measurement methods (a) to (c) of 1 to 2000 ppm by mass. (Measurement method) (a) 50.0 mg of the toner particles are stirred with 5.00 g of a 6.0 mol / L aqueous solution of nitric acid to extract the polyvalent metal elements on the surfaces of the toner particles. (b) The extract from which the polyvalent metal elements have been extracted is filtered to prepare a measurement sample. (c) The measurement sample is measured using an inductively coupled plasma mass spectrometer to determine the content of the polyvalent metal element based on the mass of the measurement sample. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to provide a toner that suppresses an increase in the liquid bridging force between the toner and the photosensitive drum in a high-temperature, high-humidity environment, and that causes less transfer roughness. [Brief explanation of the drawings]

[0008] [Figure 1] Schematic diagram of the liquid bridge strength measurement device DETAILED DESCRIPTION OF THE INVENTION

[0009] In this disclosure, unless otherwise specified, the expressions "XX to YY" or "XX to YY" representing a numerical range mean a numerical range including the lower and upper limits, which are the endpoints. When a numerical range is described in stages, the upper and lower limits of each numerical range can be combined arbitrarily. Furthermore, a monomer unit refers to the reacted form of a monomer substance in a polymer.

[0010] In electrophotography, the transfer process is the process of transferring the toner image formed on the surface of the photoreceptor to the paper. In order to obtain high-quality images, it is important to transfer the toner image formed on the photoreceptor in the development process to the paper without damaging it.

[0011] Furthermore, it is known that the transfer process is significantly affected by the environment in which it is used, and various image defects occur in both low-temperature, low-humidity and high-temperature, high-humidity environments. For example, in a low-temperature, low-humidity environment, the toner charge increases, which can cause transfer dust (the toner at the edge of the image moving to non-image areas). In a high-temperature, high-humidity environment, the toner charge decreases, which can cause a decrease in graininess in halftones (uneven image density). To solve these problems, the present inventors investigated toner particles with a controlled amount of polyvalent metal element.

[0012] However, controlling the amount of polyvalent metal elements in toner particles did not sufficiently prevent the occurrence of transfer roughness that occurs in high-temperature, high-humidity environments.The inventors' investigations revealed that the non-electrostatic adhesion force between the toner and drum is significantly different between low-temperature, low-humidity environments and high-temperature, high-humidity environments, and therefore the liquid bridging force between the toner and drum increases in high-temperature, high-humidity environments, causing transfer roughness.

[0013] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by combining the following silica fine particles with the toner particles in which the amount of the polyvalent metal element is controlled.

[0014] First, the inventors focused on the surface of silica fine particles. The surface of silica fine particles is usually hydrophilic because it contains OH groups derived from silanol structures, i.e., silanol groups, and is prone to adsorb moisture in the air. Therefore, particularly in high-temperature, high-humidity environments, the chargeability is likely to decrease due to moisture adsorption.

[0015] However, simply increasing the amount of a surface treatment agent to hydrophobize the silica particle substrate in order to reduce the silanol groups on the surface of the silica particles does not fully control the amount of silanol, and no improvement in charging performance is observed in high-temperature, high-humidity environments.Furthermore, the fluidity of the toner decreases, and image defects such as streaks and haze occur due to toner aggregation.

[0016] The present inventors have conducted extensive research into external additives that can improve chargeability and achieve charge stability, and enable image output without any adverse effects. As a result, it has been found that it is effective to use a surface treatment component of silica fine particles that has a polydimethylsiloxane structure, and to appropriately control the amount of dimethylsiloxane on the surface of the silica fine particles and the amount of Si-OR groups (where R is a hydrogen atom, a methyl group, or an ethyl group) at the terminals of the surface treatment structure.

[0017] That is, the present disclosure provides a toner containing toner particles 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: [ka] In the formula (1), n ​​represents an integer of 1 or more, When 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 mass % NaCl aqueous solution and titrated with sodium hydroxide, Sn, defined as Sn={(ab)×c×NA} / (d×e), satisfied 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 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 microparticles, 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, the area of ​​the peak whose top exists in the range of -25 to -15 ppm is defined as D, the sum of the areas of the peaks of M unit, D unit, T unit, and Q unit existing 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 5.7×10 -4 ~4.9×10 -3 and The silica particles were washed with chloroform and then measured for (D / S) / B of 1.7 x 10 -4 ~4.9×10 -3 and When the area of ​​the peak having a peak top in the range of more than -19 ppm and not more than -17 ppm in the chemical shift is defined as D1, The ratio of D1 to D (D1 / D) is 0.10 to 0.30, at least one polyvalent metal element selected from the group consisting of calcium, magnesium, aluminum, and iron is present on the surface of the toner particles; The toner has a total content of the polyvalent metal elements measured by the following measurement methods (a) to (c) of 1 to 2000 ppm by mass. (Measurement method) (a) 50.0 mg of the toner particles are stirred with 5.00 g of a 6.0 mol / L aqueous solution of nitric acid to extract the polyvalent metal elements on the surfaces of the toner particles. (b) The extract from which the polyvalent metal elements have been extracted is filtered to prepare a measurement sample. (c) The measurement sample is measured using an inductively coupled plasma mass spectrometer to determine the content of the polyvalent metal element based on the mass of the measurement sample.

[0018] The toner particles with controlled amounts of polyvalent metal elements are combined with silica particles having a polydimethylsiloxane structure, and the amount of Si-OR groups (especially Si-OH groups) in the silica particles, D By controlling SB, DSB-W, and D1 / D, the increase in the liquid bridging force between the toner and the photosensitive drum in a high-temperature, high-humidity environment can be suppressed, and the problem of transfer defects can be solved. The reason for this is explained below.

[0019] The surface treatment of the silica particles can be confirmed by time-of-flight secondary ion mass spectrometry (TOF-SIMS). In measurements of silica fine particles using time-of-flight secondary ion mass spectrometry (TOF-SIMS), it is necessary to observe fragment ions corresponding to the structure shown in formula (1). The observation of fragment ions shown in formula (1) indicates that the silica fine particles have been 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 onto the toner particles in high-temperature, high-humidity environments. [ka]

[0020] (In formula (1), n ​​is an integer of 1 or more (preferably 1 to 500, more preferably 1 to 200, even more preferably 1 to 100, and even more preferably 1 to 80).) TOF-SIMS is a method for analyzing the composition of a sample surface by irradiating the sample with ions and analyzing the mass of the secondary ions emitted from the sample. Because the secondary ions are emitted from a region several nanometers deep below the sample surface, it is possible to analyze the structure near the surface of silica microparticles. The mass spectrum of the secondary ions obtained by measurement is a set of fragment ions that reflect the molecular structure of the surface treatment agent for the silica microparticles. When silica microparticles are measured by TOF-SIMS, fragment ions corresponding to the structure represented by formula (1) are observed. In this disclosure, a structural unit having this structure is defined as a D unit. When fragment ions of D units are observed by TOF-SIMS, this means that the silica microparticles have been surface-treated with a surface treatment agent containing D units.

[0021] It is necessary to control the amount of Si-OR groups (R is a methyl group, an ethyl group, or a hydrogen atom) in the silica fine particles. The amount of Si-OR groups is the sum of the amount of Si-OR groups on the surface of the silica fine particle substrate (the silica fine particles before surface treatment) and in the surface treatment agent for the silica fine particles. The Si-OR groups are polarized, and the Si-O δ- R δ+ By having polarity as shown above and coordinating with the polyvalent metal element on the surface of the toner particles, it is possible to suppress the coordination and adsorption of water molecules on the surface of the toner particles. If the amount of Si-OR is too small, a sufficient coordination structure with polyvalent metal elements cannot be formed. Furthermore, if the amount of Si-OR is excessive, the Si-OR group can form a coordination structure, especially in high-temperature, high-humidity environments, but the Si-OR group itself will polarize and adsorb moisture, increasing the liquid cross-linking force. Among the Si-OR groups, the silanol groups (Si-OH groups) on the surface of the silica microparticle substrate are particularly susceptible to adsorbing moisture, thereby particularly increasing the liquid cross-linking force.

[0022] The amount of Si-OH groups is determined by the titration amount of sodium hydroxide. 2 This is because the Si-OH groups of the silica particle substrate and the Si-OH groups of polydimethylsiloxane undergo a neutralization reaction with sodium hydroxide.

[0023] Specifically, when 2.00 g of silica 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 with sodium hydroxide, Sn, defined as Sn={(ab)×c×NA} / (d×e), must satisfy 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 containing dispersed silica fine particles to 9.0, b is the titer (L) of NaOH 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 of the silica particles (g), e is the BET specific surface area (nm 2 / g).

[0024] Formula (2) shows the range of the amount of Si-OH groups in silica fine particles. The amount of Si-OH groups is the sum of the silanol groups on the surface of the silica fine particle substrate and the Si-OH groups in the structure derived from the surface treatment agent of the silica fine particles. Sn in formula (2) is 0.05 particles / nm 2 If the Sn concentration is less than 0.20 / nm, a sufficient coordination structure for the polyvalent metal element cannot be obtained. 2 When the density exceeds 0.17 / nm, the Si-OH group itself polarizes in a high-temperature, high-humidity environment, adsorbing moisture and increasing the liquid bridging force. 2 It is preferable that the number of particles is 0.15 particles / nm or less. 2The lower limit is more preferably 0.08 particles / nm or less. 2 It is preferable that the number of particles is 0.13 particles / nm or more. 2 More preferably, it is equal to or greater than this.

[0025] Sn can be increased by treating the silica microparticle substrate under conditions that prevent the reaction of the surface treatment agent so that Si-OH groups remain on the surface, or by adding only a small amount of the treatment agent so that it does not completely cover the surface of the silica microparticle substrate. On the other hand, Sn can be decreased by surface-treating the silica microparticles to reduce the silanol groups on the surface, or by treating with a surface treatment agent that does not have silanol groups. Extending the reaction time or increasing the temperature during surface treatment is also effective.

[0026] In addition, to control the Si-OR group, it is necessary to control the surface treatment state of the silica particles ((D / S) / B, D1 / D). The surface treatment state of the silica particles is determined by the solid 29 Si-NMR It is calculated using the DD / MAS method. With the DD / MAS measurement method, all Si atoms in the measurement sample are observed, so quantitative information can be obtained about the chemical bonding state of Si atoms in silica fine particles.

[0027] Generally, solid 29 In Si-NMR, four types of peaks can be observed for Si atoms in a solid sample: M unit (formula (4)), D unit (formula (5)), T unit (formula (6)), and Q unit (formula (7)). M unit: (R i )(R j )(R k )SiO 1 / 2 Formula (4) D units: (R g )(R h )Si(O 1 / 2 )2 formula (5) T unit:R m Si(O 1 / 2 )3 formula (6) Q units: Si(O 1 / 2 )4 formula (7) R in the formulas (4), (5), and (6) 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, a halogen atom, a hydroxy group, an acetoxy group, or an alkoxy group, which is bonded to silicon.

[0028] When silica microparticles are measured by DD / MAS, the Q unit shows a peak corresponding to the Si atoms in the silica microparticle substrate before surface treatment. In the present disclosure, when silica microparticles are surface-treated with a surface treatment agent such as silicone oil, the silica microparticles include the portion derived from the surface treatment agent. The silica microparticles before surface treatment are also referred to as the silica microparticle substrate. The BET specific surface area of ​​the silica microparticles after surface treatment is defined as B(m 2 / g). The M unit, D unit and T unit show peaks corresponding to the structures of the surface treatment agents for the silica fine particles represented by the above formulas (4) to (6), respectively. Both are solid 29 Identification is possible by the chemical shift values ​​of the Si-NMR spectrum, with Q units appearing at chemical shifts of -130 to -85 ppm, T units at -65 to -51 ppm, D units at -25 to -15 ppm, and M units at 10 to 25 ppm, and quantification can be achieved by their respective integral values. The respective peak integral values ​​are Q, T, D, and M, and the sum of these integral values ​​is S.

[0029] Silica fine particle solid 29 In the chemical shift obtained by Si-NMR DD / MAS method, the area of ​​the peak whose top is in the range of -25 to -15 ppm is defined as D, and - 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. The specific surface area of ​​the silica fine particles is defined as B (m 2 In this case, the ratio of (D / S) to B (D / S) / B (hereinafter also referred to as DSB) is 5.7 × 10 -4 ~4.9×10 -3 is. In addition, the (D / S) / B (hereinafter also referred to as DSB-W) measured after washing the silica particles with chloroform was 1.7 × 10 -4 ~4.9×10 -3 is.

[0030] DSB means the Si atomic weight per unit surface area constituting the D unit relative to the Si atomic weight of the entire silica particle. 29 In Si-NMR measurements, silica particles with a peak at the D unit indicate that they have been surface treated with a compound having a dimethylsiloxane structure. In other words, DSB represents the amount of dimethylsiloxane on the surface of silica particles per unit surface area. The smaller the DSB, the less dimethylsiloxane there is on the surface of the silica particles, and the less it inhibits flowability as an external additive. However, because silanol groups tend to remain on the surface of the silica particle substrate, the effect of moisture in relatively high humidity environments cannot be suppressed, and the particles are prone to adsorb moisture in high-temperature, high-humidity environments.

[0031] Conversely, the larger the DSB, the greater the amount of dimethylsiloxane on the surface of the silica particles, but an excess of D units inhibits fluidity as an external additive. Also, depending on the state of dimethylsiloxane treatment, silanol groups remain on the surface of the silica particle substrate, which is prone to adsorbing moisture, increasing the liquid cross-linking force. Specifically, DSBs are 5.7 × 10 -4 If the DSB range is less than 4.9 × 10, the surface treatment of the silica particles is insufficient, and the liquid bridging force increases in a high-temperature, high-humidity environment. -3 If the DSB exceeds 5.7×10, the amount of dimethylsiloxane becomes excessive, the fluidity of the toner decreases significantly, and transfer roughness occurs. -4 ~4.9×10 -3 is preferred, and 7.1 × 10 -4 ~4.9×10 -3 is more preferred.

[0032] The DSB can be increased by increasing the amount of surface treatment agent used in the surface treatment of the silica microparticle substrate or by selecting a compound with many D units, such as polydimethylsiloxane or cyclic siloxane, as the surface treatment agent, whereas the DSB can be decreased by decreasing the amount of surface treatment agent used in the surface treatment of the silica microparticle substrate or by selecting a compound with no D units, such as hexamethyldisiloxane, as the surface treatment agent.

[0033] On the other hand, we will now discuss DSB-W. As mentioned above, DSB-W is DSB obtained after washing silica particles with chloroform. This value represents the amount of silicon atoms with D units chemically bonded to the silica particles. DSB-W is 1.7 x 10 -4 If the viscosity is less than 4.9×10, the amount of surface treatment agent bonded to the surface of the silica particles will be insufficient, and the surface treatment agent will peel off from the silica particles during long-term use, resulting in an increase in the liquid bridging force in a high-temperature, high-humidity environment. -3 If the temperature exceeds this range, the fluidity will drop significantly, causing transfer lumps. DSB-W is preferably 4.9 x 10 -4 ~4.9×10 -3 and more preferably 6.0 × 10 -4 ~3.3×10 -3 (33×10 -4 )

[0034] Therefore, the silica fine particles are surface-treated with an appropriate amount of D units, and the amount of silanol on the surface of the silica fine particles is controlled within an appropriate range.

[0035] The polar group (Si-OR group) at the end of the structure derived from the surface treatment agent for the silica fine particles is defined as D1. 29 In the chemical shift obtained by Si-NMR, for peaks with peak tops in the range of more than -19 ppm and less than -17 ppm, In the silica fine particles treated with D units, D1 means an Si-OR group at the end of the D unit (more specifically, -Si(R2)-OR; R is a methyl group, an ethyl group, or a hydrogen atom, respectively). As a result of extensive research, the inventors have found that by having silica microparticles with an appropriate amount of D units and silanol, and an appropriate amount of D1, it is possible to suppress an increase in the liquid bridging force between the toner and the photosensitive drum in a high-temperature, high-humidity environment, and to suppress transfer defects, in comparison to toner particles with a controlled amount of polyvalent metal element.

[0036] The inventors speculate on the effect of D1 as follows: D1 at the end of the D unit, which has moderately high hydrophobicity, is polarized, causing the oxygen atom in the Si-OR group to have a negative charge δ-. This oxygen atom coordinates with the polyvalent metal element on the toner particle surface, thereby suppressing moisture adsorption on the toner particle surface that occurs in high-temperature, high-humidity environments, and suppressing an increase in the liquid bridging force. Additionally, compared to polar groups such as silanol groups in Q units present on the surface of the silica microparticle substrate, the polar group D1 at the end of the D unit is moderately hydrophobic. This is thought to be due to the polarity of the oxygen atom bonded to the Si to which the polar group is bonded. In addition, as represented by DSB-W, the D units are bonded to the silica microparticle substrate to a certain extent, and D1 at the end of the D unit is located at a position away from the surface of the silica microparticle substrate. From the above, D1 at the end of the D unit is more hydrophobic than the silanol groups present on the surface of the silica microparticle substrate, and therefore the impact of moisture on the silica microparticles is reduced.

[0037] Therefore, the surface of the silica particles is treated with a treatment agent containing D units, controlling the amount of silanol groups on the silica particle surface to an appropriate level, and introducing a certain amount of D1 at the end of the D units. In other words, by adjusting the amount of silanol groups in the silica particles (Sn, DSB, DSB-W, and D1 / D) to the appropriate ranges, moisture adsorption to the toner surface can be suppressed, even in high-temperature, high-humidity environments, and an increase in liquid bridging force can be suppressed. Furthermore, the appropriate fluidity of the toner leads to a uniform image on the drum, and uniform transfer pressure applied to the toner is thought to suppress transfer roughness, which is a local decrease in transfer efficiency.

[0038] Therefore, the solid of silica fine particles 29 In the chemical shift obtained by Si-NMR DD / MAS, the area of ​​the peak whose top is in the range of more than -19 ppm to -17 ppm is defined as D1, and the ratio of D1 to D (D1 / D) is 0.10 to 0.30. solid 29 The D unit peak in Si-NMR measurement is separated into two peaks, and the peak appearing in the chemical shift range of more than -19 ppm to -17 ppm or less is defined as peak D1, and the peak appearing in the chemical shift range of -23 to -19 ppm is defined as peak D2.

[0039] It is known that, among the D units measured in silica microparticles, the Si atoms bonded to the OR groups at the D unit terminals correspond to peak D1. It is also known that the Si atoms in the dimethylsiloxane chain correspond to peak D2. In other words, the larger the integral value of peak D1, the more OR groups there are at the terminals of the D units. In other words, D1 / D represents the amount of OR groups in the D units of the treatment agent. The larger D1 / D, the more OR groups there are at the terminals of the D units.

[0040] If D1 / D is less than 0.10, the amount of D1 is small, and the effect of suppressing moisture adsorption on polyvalent metal elements is insufficient, making it impossible to suppress an increase in liquid cross-linking strength. Furthermore, if D1 / D exceeds 0.30, the amount of D1 is too large, so moisture is adsorbed into the D1 structure itself, increasing the liquid cross-linking strength. D1 / D is more preferably 0.10 to 0.25, and more preferably 0.18 to 0.22.

[0041] D1 / D is derived from the structure of the treatment agent that treats the surface of silica particles, so the type of treatment agent This can be controlled by the type, amount added, and reaction conditions. For example, it is preferable to use a treatment agent having many D1 structures, or to use a cyclic siloxane such as octamethyltetrasiloxane that opens its ring and reacts with the surface of the silica fine particles, or a low-molecular-weight polydimethylsiloxane.

[0042] Furthermore, the D1 / D ratio can be increased by adjusting the reaction conditions (temperature, time) of the surface treatment agent to conditions that generate Si-OH. On the other hand, D1 / D can be decreased by using a treatment agent that does not have a D1 structure and treating under conditions that do not allow the D1 structure to form. For example, methods include treating with hexamethyldisilazane or physically attaching polydimethylsiloxane.

[0043] It is necessary that at least one polyvalent metal element selected from the group consisting of calcium, magnesium, aluminum, and iron is present on the surface of the toner particles, and the total content of the polyvalent metal elements measured by the following measurement methods (a) to (c) is 1 to 2000 ppm by mass. (Measurement method) (a) 50.0 mg of toner particles are stirred with 5.00 g of a 6.0 mol / L aqueous solution of nitric acid to extract polyvalent metal elements from the surfaces of the toner particles. (b) The extract containing the polyvalent metal elements is filtered to prepare a measurement sample. (c) The measurement sample is measured using an inductively coupled plasma mass spectrometer to determine the content of polyvalent metal elements based on the mass of the measurement sample.

[0044] By the procedure (a) in the above measurement method, the polyvalent metal present on the toner particle surface is transferred to the nitric acid aqueous solution, and therefore the degree of polyvalent metal present on the toner particle surface can be determined by the above measurement method. When the content of the polyvalent metal element is 1 ppm by mass or more, it can be determined that the polyvalent metal element is present on the surface of the toner particles.

[0045] By setting the content of the polyvalent metal element within the above range, the increase in toner charge can be suppressed in low-temperature, low-humidity environments, thereby suppressing the occurrence of transfer dust. Furthermore, the decrease in toner charge can be suppressed in high-temperature, high-humidity environments, thereby suppressing the decrease in granularity in halftone images. Furthermore, the moderately hydrophobic Si-OR groups present in the silica fine particles coordinate with the polyvalent metal elements on the toner surface, thereby suppressing moisture adsorption. Therefore, the increase in the liquid bridging force between the toner and the photoreceptor drum in high-temperature, high-humidity environments can be suppressed, thereby suppressing the occurrence of transfer dust.

[0046] The total content of polyvalent metal elements is preferably 5 to 500 ppm by mass, more preferably 10 to 100 ppm by mass, and even more preferably 20 to 60 ppm by mass. The content of the polyvalent metal element can be controlled by the amount of the polyvalent metal element added during the production of the toner particles and the pH of the toner particle dispersion. When these polyvalent metal compounds are added externally, they are removed by washing before measurement.

[0047] When the polyvalent metal element contains calcium, the calcium content measured by any of the measurement methods (a) to (c) is preferably 1 to 200 ppm by mass, more preferably 3 to 10 ppm by mass. When the polyvalent metal element contains magnesium, the magnesium content measured by any of the measurement methods (a) to (c) is preferably 2 to 400 mass ppm, more preferably 10 to 30 mass ppm. When the polyvalent metal element contains aluminum, the aluminum content measured by the methods described in measurement methods (a) to (c) is preferably 5 to 1000 mass ppm, and 1 It is more preferably 0 to 100 ppm by mass, even more preferably 20 to 60 ppm by mass, and even more preferably 30 to 50 ppm by mass. When the polyvalent metal element contains iron, the iron content measured by any of the measurement methods (a) to (c) is preferably 10 to 2000 ppm by mass, more preferably 200 to 600 ppm by mass.

[0048] The preferred content of polyvalent metal elements varies depending on the type of metal element because the ionization tendency differs depending on the type of metal element. A polyvalent metal element with a low ionization tendency is less likely to undergo stabilization by moisture adsorption and coordination of Si-OR groups than a polyvalent metal element with a high ionization tendency, so it is preferable to contain a larger amount of polyvalent metal element.

[0049] When the coverage rate of the surface of the toner particles with silica fine particles is defined as Ssi, calculated from an image of the toner surface observed with a scanning electron microscope (SEM), the Ssi is preferably 30 to 90 area %. When the coverage is 30% or more, the increase in the liquid cross-linking force is further suppressed, and the occurrence of transfer roughness can be further suppressed due to good fluidity. The coverage Ssi is more preferably 55% or less, and even more preferably 50% or less. If the Ssi is 55% by area or less, the silica particles will be released from the toner and the toner will be Embedding in the toner is suppressed, and the occurrence of transfer roughness can be further suppressed over a long period of time. The lower limit is more preferably 35 area % or more, and even more preferably 40 area % or more. The coverage rate Ssi can be controlled by the amount of silica fine particles added to the toner.

[0050] Furthermore, the content of the silica fine particles is preferably 0.3 to 2.0 parts by mass, more preferably 1.0 to 1.8 parts by mass, and even more preferably 1.2 to 1.7 parts by mass, relative to 100 parts by mass of toner particles. By setting the content of the silica fine particles within this range, the toner has more appropriate fluidity, the image on the drum becomes more uniform, and the transfer pressure applied to the toner is made uniform, thereby further suppressing transfer roughness, which is a local decrease in transfer efficiency.

[0051] Furthermore, the number-average particle size of the primary particles of the silica fine particles is preferably 5 to 50 nm, more preferably 10 to 40 nm, and even more preferably 20 to 30 nm. By externally adding silica fine particles within this particle size range to toner particles, the chargeability and fluidity of the toner are improved, and transfer roughness, transfer dust, and roughness can be more easily suppressed.

[0052] The silica fine particles may be used in combination with large-diameter silica fine particles as spacer particles, which can help prevent the silica fine particles from being buried under stresses received in a developing device, such as stress from the carrier when used as a two-component developer, or stress from the developing blade or developing sleeve when used as a one-component developer.

[0053] That is, the silica fine particles preferably contain small-sized silica fine particles and large-sized silica fine particles. The number-average particle size of the primary particles of the small-sized silica fine particles is preferably 5 to 25 nm, more preferably 5 to 20 nm. The number-average particle size of the primary particles of the large-sized silica fine particles is preferably more than 25 nm but not more than 70 nm, more preferably 30 to 40 nm. The BET specific surface area of ​​the small particle silica substrate is 100 to 500 m 2 / g, and 150 to 300m 2 / g. The BET specific surface area of ​​the large particle silica substrate is preferably 10 to 100 m 2 / g, and 30 to 80m 2 / g is more preferred. The mass ratio of the small particle silica particles to the large particle silica particles is preferably 20:1 to 5:1, and more preferably 15:1 to 15:1. It is more preferable that the ratio is 1 to 7:1. The BET specific surface area B of the silica particles after surface treatment is 40 to 200 m 2 / g, and 100 to 150m 2 / g is more preferred.

[0054] From the viewpoint of uniform charging, it is preferable that the small-sized silica particles and the large-sized silica particles are subjected to the same surface treatment. The number-average particle size of the silica particles can also be controlled by the mixing ratio of the small-sized silica particles and the large-sized silica particles.

[0055] The silica fine particles are preferably surface-treated with at least a compound represented by the following formula (3). [ka]

[0056] In equation (3), R 1 , R 2 are each independently a carbinol group, a hydroxy group, an epoxy group, a carboxy group, an alkyl group (preferably having 1 to 6 carbon atoms, more preferably having 1 to 3 carbon atoms), or a hydrogen atom. m is the average number of repeating units and is an integer of 1 to 200 (preferably 30 to 150, more preferably 70 to 130).

[0057] The surface treatment agent of formula (3) can suppress moisture adsorption in a high-temperature, high-humidity environment, while further suppressing the occurrence of transfer roughness. The surface treatment agent to be used is not particularly limited as long as it is a compound represented by formula (3), and known agents can be used. These may be used alone or in combination of two or more. Two or more types of surface treatment agents having different functional groups may be used sequentially or in admixture, or two or more types of surface treatment agents having the same functional group but different viscosities or molecular weight distributions may be used sequentially or in admixture.

[0058] The carbon fixation rate (C fixation rate) of the silica fine particles when washed with chloroform is preferably 30 to 70%, more preferably 50 to 70%, and even more preferably 60 to 65%. The carbon element contained in the silica microparticles originates 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 immobilization rate of the surface treatment agent based on the C amount corresponds to the amount of the surface treatment agent chemically bonded to the surface of the silica microparticle substrate. By controlling the carbon fixation rate of silica particles using a surface treatment agent within the above range, the coefficient of friction between the silica particles and the components inside the toner cartridge becomes appropriate. Furthermore, the amount of silanol groups on the surface of the silica particle substrate is reduced, making it easier to control the D1 / D ratio and further suppress moisture adsorption. As a result, the durability of silica particles and toners to which silica particles are externally added is further improved, and the occurrence of transfer defects can be suppressed for a long period of time.

[0059] The silica microparticles are preferably hydrophobized silica particles obtained by heat-treating a silica microparticle substrate together with a cyclic siloxane and then heat-treating it with silicone oil. The ratio (X / Y) of the amount of cyclic siloxane treated, X, to the amount of silicone oil treated, Y, is preferably 0.60 to 1.20, more preferably 0.60 to 1.10, and even more preferably 0.70 to 1.00. By controlling X / Y within the above range, it becomes easier to control the value of D1 / D within the target range. X / Y can be calculated using the following formula. X / Y = (Amount of C in silica microparticles treated with cyclic siloxane: Amount of C in intermediate) / {(Amount of C in silica microparticles treated with cyclic siloxane and then with silicone oil: Amount of C in final product) - (Amount of C in silica microparticles treated with cyclic siloxane: Amount of C in intermediate)}

[0060] As the silica particle substrate, which serves as the base material before surface treatment with silicone oil or the like, silica particles obtained by known methods can be used without particular limitation. Typical examples include fumed silica, wet process silica, and sol-gel process silica. These silicas may also be partially or entirely fused silica.

[0061] The silica fine particle substrate can be appropriately selected from fumed silica, wet silica, etc., depending on the required properties of the individual toner. In particular, fumed silica has an excellent fluidity-imparting effect and is suitable as a silica fine particle substrate used in an external additive for electrophotographic toners.

[0062] The silica particles used are those that have been surface-treated to impart hydrophobicity and fluidity to the silica particle substrate. Examples of surface treatment methods include chemical treatment with a silicon compound that reacts with or physically adsorbs to the silica particle substrate. The method for surface treatment of the silica microparticle substrate is not particularly limited, and can be carried out by contacting a surface treatment agent containing siloxane bonds with the silica microparticles.From the viewpoint of uniformly treating the surface of the silica microparticle substrate and easily achieving the above-mentioned physical properties, it is preferable to contact the silica microparticle substrate with the surface treatment agent in a dry state.As will be described later, examples of such methods include a method in which vapor of the surface treatment agent is brought into contact with the silica microparticle base material, or a method in which the undiluted solution of the surface treatment agent or a diluted solution with various solvents is sprayed and brought into contact with the silica microparticle substrate.

[0063] As a surface treatment method for the silica fine particle substrate, the method for producing silica fine particles preferably includes a first treatment step of surface treating the silica fine particle substrate with a cyclic siloxane (dry treatment), and a second treatment step of surface treating the silica fine particle substrate after the cyclic siloxane treatment with silicone oil (dry treatment).The silica fine particles are preferably silicone oil-treated products of silica fine particles treated with a cyclic siloxane.The method for producing a toner preferably includes a step of preparing the silica fine particles obtained by the above method.

[0064] 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 microparticle substrate, and also add short dimethylsiloxane chains with terminal OH groups to the surface of the silica microparticle substrate. The treatment temperature for the silica microparticle substrate surface with cyclic siloxane is preferably 300°C or higher. A treatment temperature of 300°C or higher effectively reduces silanol groups on the silica microparticle substrate surface. Furthermore, a treatment temperature of 300°C or higher causes the formation and cleavage of siloxane bonds, making it possible to treat the silica microparticle substrate surface more uniformly while uniformly controlling the siloxane chain length. The treatment temperature of the silica fine particle substrate surface with the cyclic siloxane is preferably 310° 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, more preferably 350° C. or lower.

[0065] After the above-mentioned cyclic siloxane treatment, the silica microparticle substrate after the cyclic siloxane treatment is heat-treated with silicone oil as a second treatment. The silicone oil bonds with the terminal OH group of the component reacted with the cyclic siloxane in the first treatment, and a long-chain dimethylsiloxane component can be introduced onto the surface of the silica microparticles. The temperature during the silicone oil treatment of the surface of the silica microparticle substrate is preferably 300°C or higher, more preferably 320°C or higher, and even more preferably 330°C or higher. The upper limit is not particularly limited, but is preferably 380°C or lower, and more preferably 350°C or lower. By controlling the treatment amount X of the cyclic siloxane and the treatment amount Y of the silicone oil, the silanol components on the surface of the silica fine particle substrate can be reduced, and the amount of D units and D1 can be controlled. This allows the toner to have improved charging stability without reducing its fluidity with a small surface treatment amount.

[0066] The cyclic siloxane may be at least one selected from the group consisting of low molecular weight cyclic siloxanes having up to 10 ring members, such as hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, etc. Among these, octamethylcyclotetrasiloxane is preferred. Silicone oil refers to an oily substance having a molecular structure with a siloxane bond as the main chain, and any commonly available silicone oil can be used without any particular restrictions as long as it satisfies the above-mentioned formula (3). Specific examples include silicone oils having 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.

[0067] The treatment times for the first and second treatments vary depending on the treatment temperature and the reactivity of the surface treatment agent used, but are preferably 5 minutes or more and 300 minutes or less, more preferably 30 minutes or more and 240 minutes or less, and even more preferably 50 minutes or more and 200 minutes or less. The treatment temperature and treatment time for the surface treatment within the above ranges are preferred from the viewpoints of allowing the treatment agent to react sufficiently with the silica fine particle substrate and of production efficiency.

[0068] In the first treatment, the contact of the surface treatment agent with the silica fine particle 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 a vapor contact method, it is easy to remove the surface treatment agent that does not react with the silica fine particle surface, and the surface of the silica fine particles can be appropriately covered with a modifying group having appropriate polarity. When using a vapor contact method of the surface treatment agent, it is preferable to treat at a treatment temperature equal to or higher than the boiling point of the surface treatment agent. The vapor contact may be carried out in multiple steps. When contacting with the vapor of the surface treatment agent in an inert gas atmosphere such as a nitrogen atmosphere, the pressure (gauge pressure) of the vapor of the surface treatment agent in the container is preferably 50 to 300 kPa or less, more preferably 150 to 250 kPa.

[0069] The toner particles may contain a binder resin, which may be a vinyl resin, a polyester resin, or the like, but is not particularly limited and any known resin may be used.

[0070] Specific examples of vinyl resins that can be used include 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, polyacrylic acid ester, polymethacrylic acid ester, and polyvinyl acetate, and these can be used alone or in combination of two or more. Among these, styrene copolymers and polyester resins are preferred in terms of development characteristics, fixability, etc., and polyester resins are more preferred.

[0071] The binder resin preferably contains a polyester resin, and preferably contains a polyester resin as the main component from the viewpoint of low-temperature fixability. The main component means that the content is 50% by mass to 100% by mass (preferably 80% by mass to 100% by mass). The binder resin is more preferably a polyester resin.

[0072] Monomers used for the polyester resin include polyhydric alcohols (divalent, trivalent or higher alcohols), polycarboxylic acids (divalent, trivalent or higher carboxylic acids), acid anhydrides thereof or lower alkyl esters thereof.

[0073] As the polyhydric alcohol monomer used in the polyester resin, the following polyhydric alcohol monomers can be used. Dihydric alcohol components include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, hydrogenated bisphenol A, and bisphenols represented by formula (A) and their derivatives; [ka]

[0074] (In the formula, R is an ethylene or propylene group, x and y are each an integer of 0 or more, and the average value of x+y is 0 or more and 10 or less.) Examples include diols represented by formula (B). [ka]

[0075] Examples of trihydric or higher alcohol components include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, and 1,3,5-trihydroxymethylbenzene.

[0076] Of these, glycerol, trimethylolpropane, and pentaerythritol are preferably used. These dihydric alcohols and trihydric or higher alcohols can be used alone or in combination.

[0077] As the polycarboxylic acid monomer used in the polyester resin, the following polycarboxylic acid monomers can be used. Examples of dicarboxylic acid components include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, and adipic acid. , sebacic acid, azelaic acid, malonic acid, n-dodecenylsuccinic acid, isododecenylsuccinic acid, n-dodecylsuccinic acid, isododecylsuccinic acid, n-octenylsuccinic acid, n-octylsuccinic acid, isooctenylsuccinic acid, isooctylsuccinic acid, anhydrides of these acids, and lower alkyl esters thereof. Of these, maleic acid, fumaric acid, terephthalic acid, and n-dodecenylsuccinic acid are preferably used.

[0078] Examples of trivalent or higher carboxylic acids, their acid anhydrides, and their lower alkyl esters include 1,2,4-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,2,4-cyclohexanetricarboxylic acid, tetra(methylenecarboxyl)methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, empol trimer acid, their acid anhydrides, and their lower alkyl esters.

[0079] Among these, 1,2,4-benzenetricarboxylic acid, i.e., trimellitic acid or its derivatives, is particularly preferred because it is inexpensive and the reaction can be easily controlled. These dicarboxylic acids and tricarboxylic or higher carboxylic acids can be used alone or in combination.

[0080] The method for producing the polyester resin is not particularly limited, and known methods can be used. For example, the aforementioned alcohol monomer and carboxylic acid monomer are simultaneously charged and polymerized via an esterification reaction or transesterification reaction and a condensation reaction to produce the polyester resin. The polymerization temperature is not particularly limited, but is preferably in the range of 180°C to 290°C. Polymerization of the polyester resin can use polymerization catalysts such as titanium-based catalysts, tin-based catalysts, zinc acetate, antimony trioxide, and germanium dioxide. In particular, the binder resin is preferably a polyester resin polymerized using a tin-based catalyst.

[0081] As the polymerizable monomer capable of producing the vinyl resin, a vinyl monomer capable of radical polymerization is used. The vinyl monomer may be a monofunctional monomer or a polyfunctional monomer. Examples of monofunctional monomers include styrene; styrene derivatives such as α-methylstyrene, β-methylstyrene, ο-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, and p-phenylstyrene; acrylic polymerizable monomers such as methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, dibutyl phosphate ethyl acrylate, and 2-benzoyloxyethyl acrylate; methacrylic polymerizable monomers such as methyl methacrylate, ethyl methacrylate, and dibutyl phosphate ethyl methacrylate; methylene aliphatic monocarboxylic acid esters; vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, and vinyl isobutyl ether; and vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and vinyl isopropyl ketone.

[0082] Preferably, the vinyl resin is a copolymer of styrene and a (meth)acrylic acid alkyl ester having an alkyl group with 1 to 10 carbon atoms (preferably 1 to 8, more preferably 2 to 6). More preferably, it is a copolymer of styrene and n-butyl acrylate. As a monomer that imparts an acid group, (meth)acrylic acid may be further copolymerized.

[0083] The glass transition temperature (Tg) of the toner is preferably 40° C. or higher and 70° C. or lower. When the glass transition temperature of the toner is 40° C. or higher and 70° C. or lower, the toner can maintain good fixability while improving storage stability and durability.

[0084] A charge control agent may be added to the toner particles. As the charge control agent for negative charging, organic metal complex compounds and chelate compounds are effective, and examples thereof include monoazo metal complex compounds; acetylacetone metal complex compounds; and metal complex compounds of aromatic hydroxycarboxylic acids or aromatic dicarboxylic acids. Specific examples of commercially available products include Spilon Black TRH, T-77, and T-95 (Hodogaya Chemical Co., Ltd.), and BONTRON (registered trademark) S-34, S-44, S-54, E-84, E-88, and E-89 (Orient Chemical Co., Ltd.).

[0085] Positively chargeable charge control agents include nigrosine and modified products thereof with 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 of these, and lake pigments thereof; triphenylmethane dyes and lake pigments thereof (lacquering agents include phosphotungstic acid, phosphomolybdic acid, phosphotungstomolybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide compounds, and the like); metal salts of higher fatty acids; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, and dicyclohexyltin oxide; and organotin 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 (registered trademark) N-01, N-04, N-07, P-51 (Orient Chemical Co., Ltd.), and Copy Blue PR (Clariant).

[0086] These charge control agents can be used alone or in combination of two or more. The amount of these charge control agents used is preferably 0.1 to 10.0 parts by mass, more preferably 0.1 to 5.0 parts by mass, per 100 parts by mass of binder resin, from the viewpoint of the charge amount of the toner.

[0087] A release agent may be blended into the toner particles as needed to improve fixability. The release agent is not particularly limited, and known release agents can be used. Specific examples include petroleum waxes such as paraffin wax, microcrystalline wax, and petroleum waxes and derivatives thereof, montan wax and derivatives thereof, hydrocarbon waxes produced by the Fischer-Tropsch process and derivatives thereof, polyolefin waxes such as polyethylene and polypropylene and derivatives thereof, natural waxes such as carnauba wax and candelilla wax and derivatives thereof, ester waxes, etc. Here, the derivatives include oxides, block copolymers with vinyl monomers, and graft modified products. As the ester wax, monofunctional ester wax, difunctional ester wax, and polyfunctional ester wax such as tetrafunctional or hexafunctional ester wax can be used.

[0088] The melting point of the release agent is preferably 60° C. or higher and 140° C. or lower, more preferably 70° C. or higher and 130° C. or lower. When the melting point is 60° C. or higher and 140° C. or lower, the toner is easily plasticized during fixing, improving fixability. In addition, the release agent is less likely to bleed out even when stored for a long period of time.

[0089] The toner particles may contain a colorant. Examples of the colorant include organic pigments, organic dyes, and inorganic pigments, but there is no particular limitation and any known colorant can be used. Examples of cyan colorants include copper phthalocyanine compounds and their derivatives, anthraquinone compounds, and basic dye lake compounds. Specific examples include the following: CI Pigment Blue 1, 7, 15, 15:1, 15:2, 15:3, 15:4, 60, 62, and 66.

[0090] Examples of magenta colorants include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. CI Pigment Red 2, 3, 5, 6, 7, 23, 48:2, 48:3, 48:4, 57:1, 81:1, 122, 144, 146, 150, 166, 169, 177, 184, 185, 202, 206, 220, 221, and 254. CI Pigment Violet 19.

[0091] Examples of yellow colorants include condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds. Specific examples include the following: CI Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 97, 109, 110, 111, 120, 127, 128, 129, 147, 151, 154, 155, 168, 174, 175, 176, 180, 181, 185, 191, and 194.

[0092] Examples of black colorants include carbon black, and those toned to black using the above-mentioned yellow colorants, magenta colorants, and cyan colorants. These colorants may be used alone or in combination, or in the form of a solid solution. The colorant used in the present invention is selected in consideration of hue angle, chroma, brightness, light resistance, transparency for overhead projectors, and dispersibility in toner particles.

[0093] The amount of the colorant added is preferably 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin or the polymerizable monomer that constitutes the binder resin. The toner particles are preferably non-magnetic toners that do not contain magnetic materials. In the case of non-magnetic toners, charge decay is unlikely to occur even when a strong voltage is applied in the transfer process, and therefore deterioration of graininess in halftone images can be suppressed in high-temperature, high-humidity environments.

[0094] The toner may contain, in addition to silica fine particles, other external additives such as inorganic fine particles other than silica fine particles. The toner can be obtained by externally adding silica fine particles and, if necessary, inorganic fine particles other than silica fine particles to toner particles as external additives. Examples of inorganic fine particles include metal oxide fine particles (inorganic fine particles) such as strontium titanate, fatty acid metal salts, alumina, titanium oxide, hydrotalcite compounds, zinc oxide fine particles, cerium oxide fine particles, and calcium carbonate fine particles.

[0095] As the other external additives, composite oxide particles using two or more metals can be used, or two or more types selected from these particle groups in any combination can be used. Resin particles or organic-inorganic composite particles of resin particles and inorganic particles can also be used. The other external additives may be hydrophobized with a hydrophobizing agent.

[0096] Examples of the hydrophobic treatment agent include chlorosilanes such as methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, t-butyldimethylchlorosilane, and vinyltrichlorosilane; Tetramethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, o-methylphenyltrimethoxy alkoxysilanes such as silane, p-methylphenyltrimethoxysilane, n-butyltrimethoxysilane, i-butyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, dodecyltrimethoxysilane, tetraethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, i-butyltriethoxysilane, 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; Silicone oils such as dimethyl silicone oil, methyl hydrogen silicone oil, methyl phenyl 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 oil; siloxanes such as hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, hexamethyldisiloxane, and octamethyltrisiloxane; Examples of fatty acids and metal salts thereof 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, and salts of the above fatty acids with metals such as zinc, iron, magnesium, aluminum, calcium, sodium, and lithium.

[0097] Among these, alkoxysilanes, silazanes, and silicone oils are preferably used because they are easy to hydrophobize. These hydrophobizing agents may be used alone or in combination of two or more. The content of the other external additives is preferably 0.05 parts by mass or more and 20.0 parts by mass or less with respect to 100 parts by mass of the toner particles.

[0098] The weight average particle diameter (D4) of the toner is preferably 3.0 μm or more and 12.0 μm or less, more preferably 4.0 μm or more and 10.0 μm or less. When the weight average particle diameter (D4) is in the above range, good fluidity is obtained, and the latent image can be developed faithfully.

[0099] The method for producing the toner is not particularly limited, and known methods can be used. For example, a kneading and pulverization method or a wet production method can be used. From the viewpoint of uniform particle size and shape control, a wet production method is preferred. Examples of the wet production method include a suspension polymerization method, a solution suspension method, an emulsion polymerization aggregation method, and an emulsion aggregation method, and the emulsion aggregation method is more preferred. That is, the method for producing toner particles preferably includes at least a step of aggregating fine particles of a binder resin to form aggregated particles and a step of fusing the aggregated particles to obtain toner particles. Furthermore, the toner particles are preferably emulsion-aggregated toner particles. This is because polyvalent metal elements can be easily ionized in an aqueous medium and because polyvalent metal elements can be easily incorporated into the toner particles when aggregating the binder resin.

[0100] Hereinafter, a detailed description will be given of a method for producing toner particles by emulsion aggregation. (Dispersion liquid preparation process) The binder resin particle dispersion liquid is prepared, for example, as follows: When the binder resin is a homopolymer or copolymer of a vinyl monomer (vinyl resin), the vinyl monomer is subjected to emulsion polymerization or seed polymerization in an ionic surfactant to prepare a dispersion liquid in which vinyl resin particles are dispersed in the ionic surfactant. When the binder resin is a resin other than a vinyl resin, such as a polyester resin, the resin is mixed with an aqueous medium in which an ionic surfactant or a polymer electrolyte is dissolved. Thereafter, this solution is heated to a temperature equal to or higher than the melting point or softening point of the resin to dissolve it, and a dispersion liquid is prepared in which the binder resin particles are dispersed in the ionic surfactant using a dispersing machine with strong shear force such as a homogenizer. The dispersion means is not particularly limited, and examples thereof include known dispersion devices such as a rotary shear homogenizer, a ball mill having media, a sand mill, and a dyno mill.

[0101] Alternatively, a phase inversion emulsification method may be used to prepare the dispersion. In the phase inversion emulsification method, a binder resin is dissolved in an organic solvent, and a neutralizer and a dispersion stabilizer are added as necessary. An aqueous solvent is added dropwise under stirring to obtain emulsified particles, and the organic solvent in the resin dispersion is then removed to obtain an emulsion. In this case, the order of adding the neutralizer and dispersion stabilizer may be changed. The number-average particle diameter of the binder resin particles is usually 1 μm or less, preferably 0.01 μm to 1.00 μm. If the number-average particle diameter is 1.00 μm or less, the particle diameter distribution of the final toner is favorable, and the generation of free particles can be suppressed. Furthermore, if the number-average particle diameter is within the above range, uneven distribution between toner particles is reduced, dispersion within the toner is improved, and variations in performance and reliability are reduced.

[0102] In the emulsion aggregation method, a colorant particle dispersion can be used as needed. The colorant particle dispersion is prepared by dispersing at least colorant particles in a dispersant. The number-average particle diameter of the colorant particles is preferably 0.5 μm or less, more preferably 0.2 μm or less. When the number-average particle diameter is 0.5 μm or less, diffuse reflection of visible light can be prevented, and the binder resin particles and colorant particles can be easily aggregated in the aggregation process. When the number-average particle diameter is within the above range, uneven distribution between toner particles is reduced, dispersion within the toner is improved, and variations in performance and reliability are reduced.

[0103] In the emulsion aggregation method, a wax particle dispersion can be used as needed. The wax particle dispersion is prepared by dispersing at least wax particles in a dispersant. The number-average particle diameter of the wax particles is preferably 2.0 μm or less, more preferably 1.0 μm or less. When the number-average particle diameter is 2.0 μm or less, the wax content is less uneven among toner particles, resulting in good long-term image stability. When the number-average particle diameter is within the above range, uneven distribution among toner particles is reduced, dispersion within the toner is good, and variations in performance and reliability are reduced. The combination of colorant particles, binder resin particles, and wax particles is not particularly limited and can be freely selected depending on the purpose.

[0104] In addition to the above dispersion, other particle dispersions prepared by dispersing appropriately selected particles in a dispersant may be further mixed. The particles contained in the other particle dispersion liquid are not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include internal additive particles, charge control agent particles, inorganic particles, abrasive particles, etc. These particles may be dispersed in the binder resin particle dispersion liquid or the colorant particle dispersion liquid.

[0105] Examples of dispersants contained in binder resin particle dispersions, and if necessary colorant particle dispersions, wax micro-dispersions, and other particle dispersions include aqueous media containing polar surfactants. Examples of aqueous media include water such as distilled water and ion-exchanged water, and alcohols. These may be used alone or in combination of two or more. The content of the polar surfactant cannot be generally defined and can be appropriately selected depending on the purpose.

[0106] Examples of polar surfactants include anionic surfactants such as sulfate ester salts, sulfonate salts, phosphate esters, and soaps; and cationic surfactants such as amine salts and quaternary ammonium salts. Specific examples of anionic surfactants include sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, sodium alkylnaphthalenesulfonate, and sodium dialkylsulfosuccinate. Specific examples of cationic surfactants include alkylbenzenedimethylammonium chloride, alkyltrimethylammonium chloride, distearylammonium chloride, etc. These may be used alone or in combination of two or more. These polar surfactants can also be used in combination with non-polar surfactants, such as polyethylene glycol-based, alkylphenol ethylene oxide adduct-based, and polyhydric alcohol-based nonionic surfactants.

[0107] The content of the colorant particles is preferably 0.1 to 30 parts by mass relative to 100 parts by mass of the binder resin in the aggregated particle dispersion when the aggregated particles are formed. The content of the wax particles is preferably 0.5 to 25 parts by mass, more preferably 5 to 20 parts by mass, relative to 100 parts by mass of the binder resin in the aggregated particle dispersion when the aggregated particles are formed. Furthermore, in order to more precisely control the chargeability of the resulting toner, charge control particles and binder resin particles may be added after the aggregated particles are formed. The particle sizes of the binder resin particles, colorant particles, and other particles are measured using a laser diffraction / scattering particle size distribution measuring device LA-960V2 manufactured by Horiba, Ltd.

[0108] (Agglutination process) The aggregation step of forming aggregated particles is a step of forming aggregated particles containing binder resin particles, and optionally added colorant particles and wax particles, etc., in an aqueous medium containing binder resin particles, and optionally added colorant particles and wax particles, etc.

[0109] The aggregated particles can be formed in an aqueous medium by, for example, adding and mixing an aggregating agent, a pH adjuster, and a stabilizer to the aqueous medium, and then applying appropriate temperature, mechanical power, etc. Examples of flocculants include monovalent metal salts such as sodium and potassium, divalent metal salts such as calcium and magnesium, trivalent metal salts such as iron and aluminum, and alcohols such as methanol, ethanol, and propanol.Preferably, the flocculant contains a divalent or higher metal element that has high coagulation power and can cause coagulation with the addition of a small amount.

[0110] Specific examples include divalent inorganic metal salts such as calcium chloride, calcium nitrate, magnesium chloride, magnesium sulfate, and zinc chloride. Also included are trivalent metal salts such as iron (III) chloride, iron (III) sulfate, aluminum sulfate, and aluminum chloride. Other examples include inorganic metal salt polymers such as polyaluminum chloride, polyaluminum hydroxide, polyferric sulfate, and calcium polysulfide, but are not limited to these. These may be used alone or in combination of two or more. Metal salts are selected as agglomerants, and depending on the type and amount added, the polyvalent metals on the surface of the toner particles are The amount of the elements can be controlled.

[0111] Examples of pH adjusters include alkalis such as ammonia and sodium hydroxide, and acids such as nitric acid and citric acid. The stabilizer may be a polar surfactant itself or an aqueous medium containing the same. For example, when the polar surfactant contained in each particle dispersion is anionic, a cationic stabilizer may be selected.

[0112] The flocculant and the like may be added in the form of either a dry powder or an aqueous solution in which it is dissolved in an aqueous medium, but in order to cause uniform flocculation, it is preferable to add it in the form of an aqueous solution.

[0113] The addition and mixing of the flocculant and the like is preferably carried out at a temperature equal to or lower than the glass transition temperature of the resin contained in the aqueous medium. When mixing is carried out under these temperature conditions, the flocculation proceeds in a stable state. Mixing can be carried out using, for example, a known mixing device, homogenizer, mixer, etc.

[0114] In the aggregation step, a dispersion liquid containing a polyester resin is applied to the surfaces of the aggregated particles to form a coating layer (shell), thereby obtaining toner particles having a core / shell structure in which a shell is formed on the surfaces of the core particles. The aggregation step may be repeated in stages multiple times.

[0115] (fusion process) The fusion process is a process in which the obtained aggregated particles are heated to fuse them together. Before the fusion process, a pH adjuster, a polar surfactant, a non-polar surfactant, etc. may be added as appropriate to prevent fusion between toner particles. The heating temperature may be from the glass transition temperature of the resin contained in the aggregated particles (if two or more types of resins are used, the glass transition temperature of the resin with the highest glass transition temperature) to the decomposition temperature of the resin. Therefore, the heating temperature differs depending on the type of resin in the binder resin particles and cannot be generally defined, but is generally from the glass transition temperature of the resin contained in the aggregated particles to 140°C. Heating can be carried out using a known heating device or equipment.

[0116] The fusion time is short if the heating temperature is high, and long if the heating temperature is low. In other words, the fusion time depends on the heating temperature and cannot be specified in general, but it is generally between 30 minutes and 10 hours. The toner particles obtained through the above steps can be separated into solid and liquid by a known method, and the toner particles can be recovered, and then washed, dried, etc. under appropriate conditions.

[0117] (External addition process) Toner can be obtained by adding silica fine particles to the obtained toner particles. Other external additives may be added as needed. From the viewpoint of dispersibility of the external additives, the mixing time in the external addition step is preferably 0.5 minutes or more and 10.0 minutes or less, and more preferably 1.0 minutes or more and 5.0 minutes or less. The method for producing a toner includes a step of obtaining toner particles, a step of preparing silica fine particles, and a step of externally adding and mixing the silica fine particles with the obtained toner particles to obtain a toner.

[0118] Next, the measurement methods for each physical property will be described. <Solid silica particles and silica particles washed with chloroform 29 Si-NMR Calculation method for DSB, DSB-W, and D1 / D using DD / MAS measurement Solids of silica particles and silica particles washed with chloroform 29 Si-NMR measurement The determination is carried out by separating the silica particles from the toner surface. 29 The Si-NMR measurements are described.

[0119] <Method for separating silica particles from the toner surface> When silica fine particles separated from the surface of the toner are used as a measurement sample, the silica fine particles are separated from the toner by the following procedure. A concentrated sucrose solution was prepared by adding 1.6 kg of sucrose (Kishida Chemical) to 1 L of ion-exchanged water and dissolving it in a hot water bath. 31 g of the concentrated sucrose solution and 6 mL of Contaminon N (a 10% by weight aqueous solution of a pH 7 neutral detergent for cleaning precision measuring instruments, consisting of a nonionic surfactant, an anionic surfactant, and an organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) were placed in a centrifuge tube to prepare a dispersion. 10 g of toner was added to the dispersion, and any clumps of toner were broken up using a spatula or similar tool. The centrifuge tube is placed in an Iwaki Sangyo KM Shaker (model V.SX) and shaken at 350 strokes per minute for 20 minutes. After shaking, the solution is transferred to a 50 mL glass tube for a swing-out rotor and centrifuged at 3,500 rpm for 30 minutes.

[0120] After centrifugation, the toner particles are present in the top layer of the glass tube, and the inorganic particle mixture containing silica particles is present in the lower aqueous solution. The upper and lower aqueous solutions are separated and dried, obtaining toner particles from the upper layer and an inorganic particle mixture from the lower layer. The obtained toner particles are used to measure the content of polyvalent metal elements, as described below. The above centrifugation process is repeated until the total amount of inorganic particle mixture obtained from the lower layer is 10 g or more.

[0121] Next, 10 g of the obtained inorganic fine particle mixture is dispersed in a dispersion liquid containing 100 mL of ion-exchanged water and 6 mL of Contaminon N. The obtained dispersion liquid is transferred to a glass tube (50 mL) for a swing rotor and centrifuged in a centrifuge at 3500 rpm for 30 minutes. After centrifugation, the silica particles are present in the top layer of the glass tube, and other inorganic particles are present in the aqueous solution below. The upper aqueous solution is collected and centrifuged repeatedly as necessary to separate thoroughly, after which the dispersion is dried and the silica particles are collected. The silica particles washed with chloroform are collected by the chloroform washing method described below. Next, the silica fine particles recovered from the toner particles and the solid of the silica fine particles washed with chloroform were 29 The Si-NMR measurement is carried out under the measurement conditions shown below.

[0122] <Solid 29 DD / MAS measurement conditions for Si-NMR measurement solid 29 The DD / MAS measurement conditions for Si-NMR measurement are as follows: Equipment: JNM-ECX5002 (JEOL RESONANCE) Temperature: room temperature Measurement method: DD / MAS method 29 Si 45° Sample tube: zirconia 3.2 mm diameter Sample: Filled in powder form into a test tube Sample rotation speed: 10kHz Relaxation delay: 180 seconds Scan:2000 Calibration standard: DSS (sodium 3-(trimethylsilyl)-1-propanesulfonate)

[0123] After the above measurement, the solid of the silica microparticles and the silica microparticles washed with chloroform 29 From the Si-NMR spectrum, multiple silane components with different substituents and bonding groups are subjected to curve fitting to separate the peaks into the following M units, D units, T units, and Q units. Curve fitting is performed using EXcalibur for Windows (registered trademark) version 4.2 (EX series), software for the 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" on the menu bar to perform curve fitting. Curve fitting is performed for each component so that the difference (composite peak difference) between the composite peak obtained by curve fitting and the peak of the measurement results is minimized. M unit: (R i )(Rj )(R k )SiO 1 / 2 Formula (4) D units: (R g )(R h )Si(O 1 / 2 )2 formula (5) T unit:R m Si(O 1 / 2 )3 formula (6) Q units: Si(O 1 / 2 )4 formula (7) R in the formulas (4), (5), and (6) 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, a halogen atom, a hydroxy group, an acetoxy group, or an alkoxy group, which is bonded to silicon.

[0124] Furthermore, for the D unit peak, waveform separation is performed using a Voigt function, and the area of ​​peak D1 in the range of more than -19 ppm and not more than -17 ppm is calculated. After peak separation, the integral value of the D unit present in the chemical shift range of -25 to -15 ppm is calculated. The sum S of all integral values ​​of the M, D, T, and Q units present in the range of -140 to 100 ppm is calculated, and the ratio D / S is calculated. The ratio D1 / D is also calculated from the integral values ​​of the peaks D1 and D obtained by waveform separation. The specific surface area of ​​the silica microparticles is defined as B (m 2 From the D / S (D / S) / B ratio (DSB) is calculated from the D / S (D / S) / B (D / S / B) (DSB / B), the ratio of D / S to B is calculated. Furthermore, after the silica microparticles are washed with chloroform as described below, the same NMR measurement is carried out to calculate DSB-W after washing.

[0125] <Washing silica particles with chloroform> Place 100 mL of chloroform and 1 g of silica microparticles in a centrifuge tube and stir with a spatula. Place the centrifuge tube in a KM Shaker and shake for 20 minutes at 350 strokes per minute. After shaking, transfer to a glass tube for a swing-out rotor and centrifuge at 3,500 rpm for 30 minutes. Discard the supernatant, add 100 mL of chloroform again, shake, and repeat the centrifugation procedure twice. Collect the precipitated silica microparticles and vacuum dry them at 40°C for 24 hours to obtain washed silica microparticles.

[0126] <Method for measuring fragment ions on the surface of silica fine particles using time-of-flight secondary ion mass spectrometry (TOF-SIMS)> The TOF-SIMS measurement of the silica fine particles is carried out using the silica fine particles separated from the toner by the above-mentioned method for separating the silica fine particles from the toner surface. To measure fragment ions on the surface of silica particles using TOF-SIMS, TRIFT-IV manufactured by ULVAC-PHI, Inc. is used. The analysis conditions are as follows. Sample preparation: Attaching silica particles to an indium sheet Primary ions: Au ions Accelerating voltage: 30 kV Charge neutralization mode: On Measurement mode: Positive Raster: 200 μm Measurement time: 60 seconds From the obtained mass profile of secondary ion mass / secondary ion charge number (m / z), it is confirmed whether fragment ions corresponding to the structure shown in formula (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.

[0127] <Method for measuring the Si-OH content of silica particles> The Si—OH content of the silica fine particles can be determined by the following method using silica fine particles separated from the toner by the above-mentioned method for separating silica fine particles from the toner surface. Sample solution 1 is prepared by mixing 25.0 g of ethanol and 75.0 g of 20% by mass sodium chloride aqueous solution. 2.00 g of silica microparticles are precisely weighed into a glass bottle, and a solvent made by mixing 25.0 g of ethanol and 75.0 g of 20% by mass sodium chloride aqueous solution is added to prepare sample solution 2. Sample solution 2 is stirred with a magnetic stirrer for at least 5 minutes to disperse the silica microparticles. Next, for each of sample solutions 1 and 2, measure the change in pH while adding 0.1 mol / L sodium hydroxide solution dropwise at 0.01 mL / min. Record the titer (L) of the sodium hydroxide solution when the pH reaches 9.0. 2 Amount of Si-OH per Sn (particles / nm 2 ) can be calculated. Sn = {(ab) × c × NA} / (d × e) a: NaOH titration amount (L) of sample solution 2 b: NaOH titration amount (L) of sample solution 1 c: Concentration of NaOH solution used in titration (mol / L) NA: Avogadro's number d: Mass of silica particles (g) e: BET specific surface area of ​​silica particles (nm 2 / g: specific surface area (m 2 / g)

[0128] <Method for measuring the BET specific surface area of ​​silica fine particles> The BET specific surface area of ​​silica microparticles is measured using the following procedure. The measurement device used is the "Automatic Surface Area and Pore Distribution Measurement Device TriStar3000 (Shimadzu Corporation)," which uses the constant volume gas adsorption method as its measurement method. Measurement conditions are set and measurement data is analyzed using the dedicated software "TriStar3000 Version 4.00" that comes with the device. The device is also connected to a vacuum pump, nitrogen gas piping, and helium gas piping. Nitrogen gas is used as the adsorption gas, and the value calculated using the BET multi-point method is taken as the BET specific surface area. The BET specific surface area is calculated as follows: First, nitrogen gas is adsorbed onto the silica fine particles, and the equilibrium pressure P (P a ) and the nitrogen adsorption amount V of the magnetic material a (mol g -1 ) is measured. Then, the equilibrium pressure P(P a ) is the saturated vapor pressure of nitrogen P o (P a ) is the relative pressure P r is on the horizontal axis, and the nitrogen adsorption amount V a (mol g -1 Next, the adsorption isotherm V, which is the amount of adsorption required to form a monolayer on the surface of the silica particles, is calculated. m (mol g -1 ) is calculated by applying the BET formula below. 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 varies depending on the type of sample being measured, the type of adsorbed gas, and the adsorption temperature.) The BET formula is to set the X axis to P r , Y axis is P r / V a (1-P r ), the slope is (C-1) / (V m × C), the intercept is 1 / (V m × C) (This line is called a BET plot). Slope of the line = (C-1) / (V m ×C) Line intercept = 1 / (V m ×C) P r The measured values ​​of and P r / V a (1-P r ) on a graph and draw a line using the least squares method, the slope and intercept of the line can be calculated. Using these values, the simultaneous equations for the slope and intercept above can be solved to obtain V m and C can be calculated. m and the molecular occupancy cross section of the nitrogen molecule (0.162 nm 2 ) and the BET specific surface area S (m 2 / g) is calculated. S=V m ×N×0.162×10 -18 (where N is Avogadro's number (mol -1 )

[0129] Specifically, measurements using this device are performed in the following procedure. Accurately weigh the tared weight of a thoroughly washed and dried dedicated glass sample cell (stem diameter 3 / 8 inch, volume 5 mL). Then, use a funnel to place 0.1 g of silica microparticles into this sample cell. The sample cell containing the silica microparticles is placed in a "pretreatment device VacuPrep 061 (Shimadzu Corporation)" connected to a vacuum pump and nitrogen gas piping, and vacuum degassing is continued for 10 hours at 23°C. During vacuum degassing, the valve is adjusted to gradually degas the cell so that the silica particles are not sucked into the vacuum pump. The pressure inside the cell gradually decreases as the degassing proceeds, eventually reaching 0.4 Pa (approximately 3 mTorr). After the 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 the sample cell is then precisely weighed, and the exact mass of the silica microparticles is calculated from the difference with the tare weight. During this process, the sample cell is covered with a rubber stopper to prevent the silica microparticles in the sample cell from being contaminated by moisture in the air.

[0130] Next, a dedicated isothermal jacket is attached to the sample cell containing the silica particles. A dedicated filler rod is inserted into the sample cell, and the sample cell is set in the analysis port of the instrument. The isothermal jacket is a cylindrical component with a porous inner surface and an impermeable outer surface that can draw 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 measuring the volume of the sample cell at 23°C using helium gas, then measuring the volume of the sample cell after cooling it with liquid nitrogen, again using helium gas, and converting it from the difference between these volumes. In addition, the saturated vapor pressure P o (P a ) is the P o It is measured separately and automatically using a tube.

[0131] Next, the sample cell is evacuated and then cooled with liquid nitrogen while continuing the evacuation. Nitrogen gas is then gradually introduced into the sample cell to adsorb nitrogen molecules onto the silica particles. At this time, the equilibrium pressure P(P a ) is measured at regular intervals to obtain an adsorption isotherm, which is then converted into a BET plot. The relative pressure P r The points are set to 6 points in total: 0.05, 0.10, 0.15, 0.20, 0.25, and 0.30. A line is drawn using the least squares method for the obtained measurement data, and V is calculated from the slope and intercept of the line. m Furthermore, this V m The BET specific surface area of ​​the silica fine particles is calculated using the value of

[0132] <Method for measuring the content of polyvalent metal elements on the surface of toner particles> The content of polyvalent metal elements on the toner particle surface is measured using an inductively coupled plasma mass spectrometer (ICP-MS, manufactured by Agilent Technologies). Toner particles from which silica fine particles have been removed using the above-mentioned <Method for separating silica fine particles from the toner surface> are used. For pretreatment, a 6.0 mol / L aqueous solution of nitric acid is prepared using 60% nitric acid (Kanto Chemical, Ultrapur standard) and ultrapure water. 5.00 g of 6.0 mol / L nitric acid is added to 50.0 mg of toner particles and stirred to prepare a toner particle-containing solution sample. After leaving it for 120 minutes, it is filtered using filter paper with a pore size of 1 μm to prepare a toner cake, which is then collected and stored for 1 To separate the toner particles from the toner particle-containing solution sample, 0.00 g of ultrapure water is added to the toner cake as washing water. To prepare the polyvalent metal element measurement solution sample, ultrapure water is added to the filtrate solution sample so that the total weight becomes 50.00 g.

[0133] As a blank solution sample, ultrapure water was added to 5.00 g of a 6.0 mol / L aqueous solution of nitric acid to make a total of 50.00 g, and solution samples with known contents of each polyvalent metal element were prepared, and a calibration curve was created. The amount of metal contained in the polyvalent metal element measurement sample was then quantified, thereby measuring the content of polyvalent metal elements on the toner particle surface.

[0134] <Method for calculating the coverage rate Ssi of silica fine particles on the surface of toner particles> The coverage rate Ssi of silica fine particles on the surface of a toner particle is calculated from a backscattered electron image obtained by observation with a scanning electron microscope (SEM). Backscattered electron images are also called "composition images," and the smaller the atomic number, the darker the image is detected, and the larger the atomic number, the brighter it is detected. The backscattered electron image of the toner is obtained under the following observation conditions. Below, we will describe how to obtain a backscattered electron image of the toner and how to calculate the coverage rate of silica fine particles on the surface of a toner particle.

[0135] <Method for obtaining a backscattered electron image of toner> Equipment used: ULTRA PLUS manufactured by Carl Zeiss Microscopy Co., Ltd. Accelerating voltage: 1.0 kV WD: 2.5 mm Aperture Size: 30.0 μm Detection signal: EsB (energy selective backscattered electrons) EsB Grid:700V Magnification: 20,000x Contrast: 63.0±5.0% (reference value) Brightness: 38.0±5.0% (reference value) Resolution: 1024 x 768 pixels Pretreatment: Toner is scattered on carbon tape (Pt deposition is not performed) Contrast and brightness are set appropriately according to the state of the equipment being used. The accelerating voltage and EsB Grid are set to achieve the following: obtaining structural information on the outermost surface of the toner, preventing charge-up of undeposited samples, and selectively detecting high-energy reflected electrons. The observation field is selected to be a location where the curvature of the toner is small.

[0136] <Calculation method for silica coverage of toner> The silica coverage rate is obtained by analyzing the backscattered electron image of the toner outermost surface obtained by the above method using image processing software ImageJ (developed by Wayne Rashand). The procedure is as follows: First, convert the backscattered electron image to be analyzed to 8-bit using Type in the Image menu. Next, set the Median diameter to 2.0 pixels using Filters in the Process menu to reduce image noise. Next, use the Rectangle Tool on the toolbar to select the entire backscattered electron image. Next, select Threshold from Adjust in the Image menu and specify a brightness threshold (85 to 128 (256 levels)) so that only the brightness pixels derived from silica particles in the backscattered electrons are selected. Finally, select Measure from the Analyze menu and calculate the area ratio (area %) of the selected brightness area in the backscattered electron image. The above procedure is carried out for 20 fields of view for the toner to be evaluated, and the arithmetic mean value is taken as the coverage rate Ssi of the silica fine particles on the surface of the toner particles.

[0137] <Method for measuring the number-average particle size of silica fine particles> The number-average particle diameter of the silica particles was determined by observing the toner surface with a scanning electron microscope (SEM). It is measured from the acquired secondary electron image.

[0138] (Method for obtaining a secondary electron image of toner) Equipment used: ULTRA PLUS manufactured by Carl Zeiss Microscopy Co., Ltd. Accelerating voltage: 1.0 kV WD: 2.5 mm Aperture Size: 30.0 μm Detected signal: SE2 (secondary electron image) Magnification: 50,000x Resolution: 1024 x 768 pixels Pretreatment: Toner is scattered on carbon tape (Pt deposition is not performed) From the obtained secondary electron image, the longest diameter of 100 primary particles of the silica fine particles on the surface of the toner particle is measured, and the average value is taken as the number average particle diameter of the silica particles.

[0139] <Method for measuring the carbon content of silica particles> The C amount (carbon amount) derived from the hydrophobic treatment agent of the silica fine particles is measured using a carbon / sulfur analyzer manufactured by HORIBA (trade name: EMIA-320). A sample of 0.3 g of silica microparticles was weighed out and placed in the crucible for the carbon / sulfur analyzer. To this was added 0.3 g ± 0.05 g of tin (supplementary part number 9052012500) and 1.5 g ± 0.1 g of tungsten (supplementary part number 9051104100) as combustion improvers. The silica microparticles were then heated to 1100°C in an oxygen atmosphere according to the instructions in the instruction manual for the carbon / sulfur analyzer. This thermally decomposed the hydrophobic groups on the surface of the silica microparticles, which were derived from the hydrophobic treatment agent, into CO2, and the amount of CO2 was measured. The amount of carbon (mass%) contained in the silica microparticles was calculated from the amount of CO2 obtained.

[0140] <Calculation method for carbon fixation rate of silica fine particles> (Washing with chloroform: Extraction of unimmobilized treatment agent) The silica fine particles separated from the toner by the above-mentioned method for separating the silica fine particles from the toner surface can be used. Place 0.50 g of silica microparticles and 40 mL of chloroform in an Erlenmeyer flask, cover, and stir (magnetically) for 2 hours. Then, stop stirring and let stand for 12 hours. Next, centrifuge and remove all of the supernatant. Centrifugation was performed using a KOKUSAN centrifuge (product name: H-9R) with a Bn1 rotor and a Bn1 rotor-compatible poly centrifuge tube at 20°C, 10,000 rpm, and 5 minutes.

[0141] The centrifuged silica microparticles were placed back into the Erlenmeyer flask, 40 mL of chloroform was added, the flask was capped, and the mixture was stirred (magnetically) for 2 hours. The stirring was then stopped and the mixture was left to stand for 12 hours. The mixture was then centrifuged and the supernatant liquid was removed. This process was repeated two more times. The resulting sample was then dried at 50°C for 2 hours in a thermostatic chamber. The pressure was then reduced to 0.07 MPa, and the mixture was then dried at 50°C for 24 hours to fully volatilize the chloroform.

[0142] (C amount measurement) The carbon content of the silica microparticles washed with chloroform as described above and the carbon content of the silica microparticles before washing with chloroform are measured according to the "Method for measuring carbon content of silica microparticles" described above. The carbon content fixation rate of the silica microparticles can be calculated using the following formula: C amount fixation rate [%] = (C amount of silica particles treated with chloroform / C amount of silica particles before washing with chloroform) × 100

[0143] <Measurement of weight average particle diameter (D4) and number average particle diameter (D1) of toner (particles)> The weight average particle size (D4) and number average particle size (D1) of the toner (particles) are measured with an effective number of 25,000 measurement channels using a precision particle size distribution measuring device equipped with a 100 μm aperture tube and using the narrow hole electrical resistance method, "Coulter Counter Multisizer 3" (registered trademark, manufactured by Beckman Coulter, Inc.), and the accompanying dedicated software "Beckman Coulter Multisizer 3 Version 3.51" (manufactured by Beckman Coulter, Inc.), for setting measurement conditions and analyzing measurement data, and are calculated by analyzing the measurement data. The aqueous electrolyte solution used for the measurement is prepared by dissolving special grade sodium chloride in ion-exchanged water to a concentration of approximately 1% by mass, such as "ISOTON II" (manufactured by Beckman Coulter). Before performing measurements and analysis, the dedicated software is set up as follows. In the "Change Standard Measurement Method (SOM)" screen of the dedicated software, set the total count in control mode to 50,000 particles, the number of measurements to 1, and the Kd value obtained using "Standard Particles 10.0 μm" (Beckman Coulter). Press the threshold / noise level measurement button to automatically set the threshold and noise level. Also, set the current to 1600 μA, the gain to 2, the electrolyte to ISOTON II, and check "Flush aperture tube after measurement." In the dedicated software's "Pulse to particle size conversion setting screen," set the bin interval to logarithmic particle size, the particle size bin to 256 particle size bins, and the particle size range to 2 μm or more and 60 μm or less.

[0144] The specific measurement method is as follows. (1) Pour approximately 200 ml of the electrolyte solution into a 250 ml round-bottom glass beaker made specifically for the Multisizer 3, set it on the sample stand, and stir the stirrer rod counterclockwise at 24 revolutions per second. Then, use the "aperture tube flush" function of the dedicated software to remove any dirt and air bubbles from inside the aperture tube. (2) Approximately 30 ml of the above-mentioned aqueous electrolyte solution is placed in a 100 ml flat-bottom glass beaker, and approximately 0.3 ml of a dilution obtained by diluting "Contaminon N" (a 10% by weight aqueous solution of a neutral detergent for cleaning precision measuring instruments, pH 7, consisting of a nonionic surfactant, anionic surfactant, and organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) three times by weight with ion-exchanged water is added as a dispersant. (3) A predetermined amount of ion-exchanged water is placed in the water tank of an ultrasonic disperser, "Ultrasonic Dispersion System Tetora150" (manufactured by Nikkaki Bios Co., Ltd.), which has two built-in oscillators with an oscillation frequency of 50 kHz and a phase difference of 180 degrees and an electrical output of 120 W, and approximately 2 ml of the Contaminon N is added to this water tank. (4) Set the beaker (2) in the beaker fixing hole of the ultrasonic disperser, operate the ultrasonic disperser, and adjust the height of the beaker so that the resonance state of the liquid surface of the electrolytic solution in the beaker is maximized. (5) While ultrasonic waves are irradiated to the electrolyte solution in the beaker in (4), approximately 10 mg of toner (particles) is added little by little to the electrolyte solution and dispersed. The ultrasonic dispersion process is then continued for another 60 seconds. During the ultrasonic dispersion, the water temperature in the water tank is appropriately adjusted to be between 10°C and 40°C. (6) Using a pipette, add the electrolytic solution (5) containing dispersed toner particles to the round-bottom beaker (1) placed in the sample stand, and adjust the measurement concentration to approximately 5%. Then, measure the particle count until it reaches 50,000 particles. (7) The measurement data is analyzed using the dedicated software provided with the device to calculate the weight-average particle size (D4). Note that when the dedicated software is set to Graph / Volume %, the "Average diameter" on the Analysis / Volume Statistics (Arithmetic Mean) screen is the weight-average particle size (D4), and when the dedicated software is set to Graph / Number %, the "Average diameter" on the Analysis / Number Statistics (Arithmetic Mean) screen is the number-average particle size (D1). [Example]

[0145] The present invention will be explained in more detail below with reference to Production Examples and Examples, which are not to be construed as limiting the scope of the present invention. Note that all parts in the following formulations are parts by mass.

[0146] <Production example of silica fine particles 1> Untreated dry silica (primary particle number average particle size 15 nm, BET specific surface area 200 m) was used as small-particle inorganic fine particles. 2 / g) and untreated dry silica (primary particle number average particle size 35 nm, BET specific surface area 50 m) as large particle inorganic fine particles. 2 The mixture was charged with 10:1 mass ratio of 1 / g and heated to 330°C while being fluidized by stirring. The atmosphere inside the reactor was replaced with nitrogen gas, the reactor was sealed, and octamethylcyclotetrasiloxane (D4) was sprayed and mixed as a first surface treatment agent using a spray nozzle until the gauge pressure reached 200 kPa. Heating and stirring were then continued for 1 hour to allow the reaction to proceed, thereby carrying out a coating treatment. After the treatment, the reaction system was replaced with a nitrogen atmosphere and heated again to 330°C. Subsequently, 100 parts of the untreated dry silica were sprayed with 10 parts of dimethyl silicone oil (KF-96-50CS manufactured by Shin-Etsu Chemical Co., Ltd.) as a second surface treatment agent, and the mixture was similarly coated for 1 hour to obtain silica microparticles 1. The physical properties of silica microparticles 1 are shown in Table 1-2.

[0147] <Production Examples of Silica Microparticles 2 to 6> Silica microparticles 2 to 6 were obtained in the same manner as in the production example of silica microparticles 1, except that the reaction time of the first surface treatment agent and the number of parts of the second surface treatment agent were changed as shown in Table 1-1. The physical properties of silica microparticles 2 to 6 are shown in Table 1-2. With regard to the structure of the second treatment component in Table 1-1, the structure of the substituent of the compound represented by formula (3) is shown.

[0148] <Production example of silica fine particles 7> Untreated dry silica (primary particle number average particle size 15 nm, BET specific surface area 200 m) was used as small-particle inorganic fine particles. 2 / g) and untreated dry silica (primary particle number average particle size 35 nm, BET specific surface area 50 m) as large particle inorganic fine particles. 2 Silica microparticles 7 were obtained in the same manner as in the production example of silica microparticles 1, except that silica microparticles 7 (1 / g) were added in a mass ratio of 6:1. The physical properties of silica microparticles 7 are shown in Table 1-2.

[0149] <Production example of silica fine particles 8> The inorganic fine particles were untreated dry silica (primary particle number average particle size 15 nm, BET specific surface area 200 m 2 Silica microparticles 8 were obtained in the same manner as in the production example of silica microparticles 1, except that only 100% silica microparticles (1 / g) was added. The physical properties of silica microparticles 8 are shown in Table 1-2.

[0150] <Production Examples of Silica Microparticles 9 to 14> Silica microparticles 9 to 14 were obtained in the same manner as in Production Example 1 of Silica Microparticles 1, except that the second surface treatment agent was a silicone oil modified with both ends of carbinol (KF-6002 manufactured by Shin-Etsu Chemical Co., Ltd.), and the BET specific surface area of ​​the untreated dry silica added, the reaction time of the first surface treatment agent, and the number of parts of the second surface treatment agent were changed as shown in Table 1-1. The physical properties of Silica Microparticles 9 to 14 are shown in Table 1-2.

[0151] <Production example of silica fine particles 15> The inorganic fine particles were untreated dry silica (primary particle number average particle size 15 nm, BET specific surface area 200 m 2 1 / g) was added and heated to 290°C while being fluidized by stirring. The inside of the reactor was replaced with nitrogen gas, the reactor was sealed, and octamethylcyclotetrasiloxane was sprayed and mixed as a first surface treatment agent using a spray nozzle until the gauge pressure reached 100 kPa. Thereafter, heating and stirring were continued for 1 hour to allow the reaction to proceed, thereby carrying out a coating treatment. After the treatment, the reaction system was replaced with a nitrogen atmosphere and heated again to 290°C. As a surface treatment agent, 15 parts of dimethyl silicone oil (KF-96-50CS manufactured by Shin-Etsu Chemical Co., Ltd.) was sprayed onto 100 parts of untreated dry silica, and coating treatment was similarly carried out for 1 hour to obtain silica microparticles 15. The physical properties of silica microparticles 15 are shown in Table 1-2.

[0152] <Manufacturing example of silica fine particles 16> The inorganic fine particles were untreated dry silica (primary particle number average particle size 15 nm, BET specific surface area 200 m 2 1 / g) was added and heated to 250°C while being fluidized by stirring. The reactor was then flushed with nitrogen gas and sealed, and octamethylcyclotetrasiloxane was sprayed and mixed as a first surface treatment agent using a spray nozzle until the gauge pressure reached 100 kPa. Heating and stirring were then continued for 1 hour to carry out a reaction, resulting in a coating treatment and obtaining silica microparticles 16. The physical properties of silica microparticles 16 are shown in Table 1-2.

[0153] <Production example of silica fine particles 17> The inorganic fine particles were untreated dry silica (primary particle number average particle size 15 nm, BET specific surface area 200 m 2 100 parts of untreated dry silica were sprayed with 30 parts of dimethyl silicone oil (KF-96-50CS manufactured by Shin-Etsu Chemical Co., Ltd.) to cover the silica, and the coating treatment was carried out for 1 hour, yielding silica microparticles 17. The physical properties of silica microparticles 17 are shown in Table 1-2.

[0154] <Production examples of silica particles 18 and 19> Silica microparticles 18 and 19 were obtained in the same manner as in the production example of silica microparticles 17, except that the number of parts of dimethyl silicone oil and the treatment temperature were changed as shown in Table 1-1. The physical properties of silica microparticles 18 and 19 are shown in Table 1-2.

[0155] <Manufacturing example of silica fine particles 20> The inorganic fine particles were untreated dry silica (primary particle number average particle size 15 nm, BET specific surface area 200 m 2 25 parts of hexamethyldisilazane per 100 parts of untreated dry silica was sprayed using a spray nozzle as a first surface treatment agent. Heating and stirring were then continued for 1 hour to allow the mixture to react, thereby carrying out a coating treatment. After treatment, the atmosphere inside the reaction system was replaced with a nitrogen atmosphere, and the mixture was again heated to 250°C. Subsequently, 10 parts of dimethyl silicone oil (KF-96-50CS manufactured by Shin-Etsu Chemical Co., Ltd.) was sprayed as a second surface treatment agent, and coating treatment was similarly carried out for another hour to obtain silica microparticles 20. The physical properties of silica microparticles 20 are shown in Table 1-2.

[0156] <Manufacturing example of silica fine particles 21> The inorganic fine particles were untreated dry silica (primary particle number average particle size 15 nm, BET specific surface area 200 m 2 / g) was added and heated to 250°C while being fluidized by stirring. The reactor was then purged with nitrogen gas and sealed, and 25 parts of hexamethyldisilazane was sprayed as a first surface treatment agent to 100 parts of untreated dry silica using a spray nozzle. Heating and stirring were then continued for 1 hour to cause a reaction, resulting in a coating treatment and obtaining silica microparticles 21. The physical properties of silica microparticles 21 are shown in Table 1-2.

[0157] <Production example of polyester resin 1> A reactor equipped with a stirrer, a thermometer, and an outflow cooler was charged with 47 moles of terephthalic acid, 3 moles of isophthalic acid, 26 moles of ethylene oxide-modified bisphenol A (2-mol adduct), 18 moles of ethylene glycol, and 1000 ppm of tetrabutoxytitanium (as a concentration based on the mass of the entire monomer mixture), and the esterification reaction was carried out at 190°C. Thereafter, 6 moles of trimellitic anhydride (TMA) was added, and the temperature was raised to 220°C while the pressure in the system was gradually reduced, and a polycondensation reaction was carried out at 150 Pa to obtain polyester resin 1 (Mw: 38,000, softening point 118°C).

[0158] <Preparation of Resin Particle Dispersion 1> Polyester resin 1: 100.0 parts and 350 parts of ion-exchanged water were placed in a stainless steel container and heated to 95°C in a hot bath to melt. While thoroughly stirring at 7,800 rpm using a homogenizer (IKA Ultra Turrax T50), 0.1 mol / L sodium bicarbonate was added to adjust the pH to greater than 7.0. Thereafter, a mixed solution of 3 parts of sodium dodecylbenzenesulfonate and 300 parts of ion-exchanged water was gradually added dropwise to emulsify and disperse the mixture, thereby obtaining a polyester resin particle dispersion. The dispersion was cooled to room temperature, and ion-exchanged water was added to obtain resin particle dispersion 1 having a solids concentration of 12.5 mass% and a volume-based median diameter of 0.2 μm.

[0159] <Preparation of Resin Particle Dispersion 2> 78.0 parts of styrene, 20.7 parts of butyl acrylate, 1.3 parts of acrylic acid as a carboxyl group-imparting monomer, and 3.2 parts of n-lauryl mercaptan were mixed and dissolved, and an aqueous solution of 1.5 parts of Neogen RK (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) in 150 parts of ion-exchanged water was added to this solution and dispersed. An aqueous solution of 0.3 parts potassium persulfate and 10 parts ion-exchanged water was added with slow stirring for another 10 minutes. After purging with nitrogen, emulsion polymerization was carried out at 70°C for 6 hours. After polymerization was completed, the reaction solution was cooled to room temperature, and ion-exchanged water was added to obtain resin particle dispersion 2 with a solids concentration of 12.5 mass% and a volume-based median diameter of 0.2 μm.

[0160] <Preparation of wax dispersion> 100 parts of hydrocarbon wax (melting point: 77°C) and 15 parts of NEOGEN RK were mixed with 385 parts of ion-exchanged water, and dispersed for about 1 hour using a wet jet mill JN100 (manufactured by Joko Co., Ltd.) to obtain a wax dispersion. The concentration of the wax dispersion was 20% by mass.

[0161] <Preparation of Colorant Dispersion 1> As colorants, CI Pigment Blue 15:3 (100 parts) and 15 parts of Neogen RK were mixed with 885 parts of ion-exchanged water, and dispersed for about 1 hour using a wet jet mill JN100 to obtain Colorant Dispersion Liquid 1.

[0162] <Production example of toner particle 1> 265 parts of resin particle dispersion 1, 20 parts of wax dispersion, and 20 parts of colorant dispersion 1 were dispersed using a homogenizer (IKA Ultra Turrax T50). The temperature inside the container was adjusted to 30°C while stirring, and a 1 mol / L aqueous sodium hydroxide solution was added to adjust the pH to 8.0 (pH adjustment 1). As a flocculant, an aqueous solution of 0.23 parts aluminum chloride dissolved in 10 parts ion-exchanged water was added over 10 minutes at 30°C while stirring. After leaving it for 3 minutes, the temperature was raised to 50°C to generate associated particles. In this state, the particle size of the associated particles was measured using a Coulter Counter Multisizer 3 (registered trademark, manufactured by Beckman Coulter, Inc.). When the weight-average particle size reached 6.0 μm, 0.9 parts sodium chloride and 5.0 parts Neogen RK were added to stop particle growth.

[0163] After adjusting the pH to 9.0 by adding 1 mol / L aqueous sodium hydroxide solution, the temperature was raised to 95° C. to spheronize the aggregated particles. When the average circularity reached 0.980, the temperature was lowered and the mixture was cooled to room temperature, thereby obtaining toner particle dispersion 1. Hydrochloric acid was added to the obtained toner particle dispersion liquid 1 to adjust the pH to 1.5, and the mixture was left to stand with stirring for 1 hour. The mixture was then subjected to solid-liquid separation using a pressure filter to obtain a toner cake. This was reslurried with ion-exchanged water to form a dispersion again, and then subjected to solid-liquid separation using the aforementioned filter. The reslurrying and solid-liquid separation were repeated until the electrical conductivity of the filtrate became 5.0 μS / cm or less, and then final solid-liquid separation was performed to obtain a toner cake. The obtained toner cake was dried and further classified using a classifier to obtain toner particles 1.

[0164] <Production Example of Toner Particle 2> Toner particles 2 were obtained in the same manner as in the preparation example of toner particles 1, except that resin particle dispersion liquid 1 to be added was changed to resin particle dispersion liquid 2.

[0165] <Production Example of Toner Particle 3> Toner particles 3 are obtained in the same manner as toner particles 1, except that the amount of the aggregating agent added is 0.08 parts and the toner particle dispersion is adjusted to pH 1.0 by adding hydrochloric acid.

[0166] <Production Example of Toner Particle 4> Toner particles 4 are obtained in the same manner as toner particles 1, except that the coagulant is changed to aluminum chloride 1-pentanol 500 parts, which is added dropwise over 1 hour, and the pH is adjusted to 2.0.

[0167] <Preparation Example of Toner Particle 5> Toner particles 5 are obtained in the same manner as toner particles 1, except that the aggregating agent is changed from aluminum chloride to iron (III) chloride and the amount added is 0.50 parts.

[0168] <Production Example of Toner Particle 6> Toner particles 6 were obtained in the same manner as toner particles 1, except that the coagulant was changed from aluminum chloride to iron (III) chloride, the amount added was 0.30 parts, and hydrochloric acid was added to the toner particle dispersion to adjust the pH to 1.0.

[0169] <Preparation Example of Toner Particle 7> Toner particles 7 were obtained in the same manner as toner particles 1, except that the coagulant was changed from aluminum chloride to iron (III) chloride, the amount added was 2.80 parts, and hydrochloric acid was added to the toner particle dispersion to adjust the pH to 2.0.

[0170] <Preparation Example of Toner Particle 8> Toner particles 8 are prepared in the same manner as toner particles 1, except that the aggregating agent is changed from aluminum chloride to calcium chloride and the amount added is 0.10 parts.

[0171] <Production Example of Toner Particle 9> Toner particles 9 were obtained in the same manner as toner particles 1, except that the coagulant was changed from aluminum chloride to calcium chloride, the amount added was 0.05 parts, and hydrochloric acid was added to the toner particle dispersion to adjust the pH to 1.0.

[0172] <Example of preparation of toner particles 10> Toner particles 10 were obtained in the same manner as toner particles 1, except that the coagulant was changed from aluminum chloride to calcium chloride, the amount added was 1.60 parts, and hydrochloric acid was added to the toner particle dispersion to adjust the pH to 2.0.

[0173] <Preparation Example of Toner Particle 11> Toner particles 11 are obtained in the same manner as toner particles 1, except that the aggregating agent is changed from aluminum chloride to magnesium sulfate and the amount added is 0.15 parts.

[0174] <Example of preparation of toner particles 12> Toner particles 12 were obtained in the same manner as toner particles 1, except that the coagulant was changed from aluminum chloride to magnesium sulfate, the amount added was 0.08 parts, and hydrochloric acid was added to the toner particle dispersion to adjust the pH to 1.0.

[0175] <Preparation Example of Toner Particle 13> Toner particles 13 were obtained in the same manner as toner particles 1, except that the coagulant was changed from aluminum chloride to magnesium sulfate, the amount added was 1.80 parts, and hydrochloric acid was added to the toner particle dispersion to adjust the pH to 2.0.

[0176] <Preparation Example of Toner Particle 14> Toner particles 14 are obtained in the same manner as toner particles 1, except that 0.50 parts of iron (III) chloride is added in addition to aluminum chloride as an aggregating agent.

[0177] <Preparation Example of Toner Particle 15> Toner particles 15 are obtained in the same manner as toner particles 1 except that 0.05 parts of calcium chloride is added in addition to aluminum chloride as the aggregating agent.

[0178] <Production Example of Toner Particle 16> Toner particles 16 were obtained in the same manner as toner particles 1, except that the amount of aluminum chloride added as the aggregating agent was 2.00 parts, 2.80 parts of iron (III) chloride was added, and hydrochloric acid was added to the toner particle dispersion to adjust the pH to 2.0.

[0179] <Production Example of Toner Particle 17> Toner particles 17 are obtained in the same manner as toner particles 1, except that the amount of the aggregating agent added is 0.08 parts and the pH is adjusted to 0.8 by adding hydrochloric acid to the toner particle dispersion.

[0180] <Production of Toner 1> Using an FM mixer (FM-10B manufactured by Nippon Coke & Engineering Co., Ltd.), 1:100 parts of toner particles and 1:1.5 parts of silica fine particles were mixed for 180 seconds at a rotation speed of 3500 rpm to obtain a toner mixture. Thereafter, coarse particles were removed using a 300 mesh (opening 48 μm) sieve to obtain Toner 1. The production conditions and physical properties are shown in Tables 2-1 and 2-2.

[0181] <Toner 2-39> Toners 2 to 39 were produced in the same manner as in the production example of Toner 1, except that the toner particles, the type of silica fine particles, and the amount of silica fine particles added were changed as shown in Tables 2-1 and 2-2. The production conditions and physical properties are shown in Tables 2-1 and 2-2.

[0182] The obtained toner was subjected to the following evaluations. (1) Liquid cross-linking strength evaluation method The liquid crosslinking force is evaluated using a vibration type adhesion measuring device reported in KONICA MINOLTA TECHNOLOGY REPORT VOL. 1 (2004) p. 16.

[0183] The outline of the device is that toner mixed with a magnetic carrier and triboelectrically charged is developed on the sample stage using a two-component development method, and then electrostatically attached. The sample stage is coated with polycarbonate, which is also used on the surface of the photoreceptor. The sample stage is also attached to a vibration unit that has a piezoelectric vibrator connected to a horn for amplitude amplification, and the vibrator is vibrated to apply vibration acceleration to the toner. The vibration acceleration is 0 to 2 mm / sec. 2 The state of the toner being separated from the sample electrode was observed by a CCD, and the area ratio of the toner was measured as 50% from the initial state. The vibration acceleration at the time of release is calculated.

[0184] Here, if the vibration amplitude is A, the vibration angular velocity of the vibrator is ω, and the mass of the toner is m, the inertial force acting on the toner is F=mAω 2 The gravity of the toner is small enough compared to the adhesive force that it can be ignored. The inertial force when the toner is released is equal to the adhesive force of the toner, so it is calculated using the above formula.

[0185] Measurements are performed under high temperature and high humidity conditions and low temperature and low humidity conditions, and the difference between the adhesive force under high temperature and high humidity conditions and the adhesive force under low temperature and low humidity conditions is taken as the liquid bridging force to evaluate the liquid bridging force of the toner. At this time, the mass m of the toner is calculated as m=π / 6×r, where r is the number average particle diameter of the toner and ρ is the true density of the toner. 3 ×ρ.

[0186] An outline of the liquid bridging force measuring device is shown in Figure 1. 3 g of toner is placed in the developing device 1, and the developing sleeve 1-1 is rotated to coat the toner onto the sleeve 1-1. At this time, the toner coated on the sleeve 1-1 is visually confirmed, and if the amount of toner needs to be adjusted, the distance between the developing blade (not shown in the figure) equipped on the developing device and the sleeve 1-1 is adjusted. The vibration unit 2 is composed of a vibrator 2-1, a horn 2-2, and a sample stage 2-3, and a thin film of polycarbonate resin (bisphenol Z type, trade name: Iupilon Z200, manufactured by Mitsubishi Gas Chemical Co., Ltd.) is adhered to the surface of the sample stage 2-3. While rotating the developing sleeve 1-1, the vibration unit 2 was moved so as to pass over the sleeve 1-1 (developing position). At that time, the sleeve 1-1 was rotated at a speed of 0.1 m / sec, and the vibration unit 2 was moved at a speed of 0.001 m / sec. Furthermore, when the vibration unit 2 passes over the sleeve 1-1, a voltage is applied between the sleeve 1-1 and the sample stage 2-3 to develop (fly) the toner onto the sample stage 2-3. The electric field strength at this time can be adjusted by the voltage applied between the sleeve 1-1 and the sample stage 2-3 and the gap between them, depending on the amount of triboelectric charge of the toner, etc. A good guideline is an electric field strength of 0.5 V / m.

[0187] After developing the toner on the sample stage 2-3, the vibration unit 2 is moved to the vibration position, and the state of toner adhesion is confirmed using the objective lens 3-1 and the CCD 3-3 equipped with the lens barrel 3-2. The lens 3-1 and CCD 3-3 are selected so that the performance of the detection unit 3 has a resolution of 0.22 μm and a field of view of 570 μm × 427 μm. Here, the toner adhesion state is determined as a state in which one to two layers of toner are stacked over the entire field of view. The state is determined using the image from the detection unit 3, based on whether toner particles are present over the entire field of view after development compared to before development.

[0188] After toner is attached to the sample stage 2-3, an ionizer (not shown) is used to remove static electricity from the toner, and the sample stage 2-3 is vibrated by the vibrator 2-1. The signal is amplified from the oscillator 4 through the vibrator 2-1 and the horn 2-2, and the sample stage 2-3 is vibrated. The vibration acceleration (= Aω 2 ) ranges from 0 to 2×10 6 m / sec 2 The sample stage 2-3 is configured to be vibrated intermittently by dividing the sample stage 2-3 into 24. Incidentally, during the vibration, a vacuum cleaner 5 is used to collect the toner that has come off the sample stage 2-3.

[0189] The toner adhesion state is synchronized so that it is captured from the CCD 3-3 to the personal computer 3-4 after vibration acceleration is applied to the sample stage 2-3. 6m / sec 2 After applying vibration acceleration up to 1000 rpm, the state of the toner is image-processed using image processing software (Photoshop, manufactured by Adobe). Specifically, when the obtained image is binarized, the areas where toner has adhered are converted to black. When no vibration acceleration is applied, toner is present in the entire field of view, so the area ratio of the areas converted to black is close to 100%. When the vibration acceleration is increased from there, When the toner separates from the sample stage 2-3 at this rate, the area ratio of the blackened area decreases. The toner inertia force (=adhesion force F) is calculated using the above formula from the vibration acceleration given when this area ratio reaches 50%. The difference in adhesive strength between the adhesive strength in a high-temperature, high-humidity environment and the adhesive strength in a low-temperature, low-humidity environment was evaluated as the liquid crosslinking strength, and a grade of C or higher was judged to be good. A: Liquid bridging force is less than 10 nN B: Liquid cross-linking strength is 10nN or more and less than 20nN C: Liquid cross-linking force is 20nN or more but less than 30nN D: Liquid cross-linking force is 30nN or more and less than 40nN E: Liquid cross-linking force is 40nN or more but less than 50nN F: Liquid cross-linking force is 50nN or more

[0190] The methods used to evaluate each of Toners 1 to 39 are described below, and the evaluation results are shown in Table 3. The evaluation method and criteria are as follows. The image forming device used was a commercially available laser printer "LBP-9660Ci (Canon)" modified to have a process speed of 325 mm / sec. The process cartridge used was a commercially available toner cartridge (cyan) (Canon).

[0191] The product toner was removed from the inside of the cartridge, and after cleaning with an air blower, 270 g of each toner to be evaluated was filled in. Note that the product toner was removed from each of the yellow, magenta, and black stations, and the yellow, magenta, and black cartridges with the remaining toner detection mechanism disabled were inserted and evaluated.

[0192] (2) Transcription Voso Evaluation The above process cartridge, the modified laser printer, and evaluation paper CS-680 (A4, basis weight 68 g / m) with different smoothness were used. 2 , smoothness 45 seconds, sold by Canon USA), Multi-Purpose Paper (A4, basis weight 75 g / m 2 The paper (sold by Canon USA, smoothness 25 seconds) was left in a high temperature and humidity environment (30°C / 80%RH) for 24 hours. By using evaluation paper with low smoothness and large unevenness, it is possible to make a more rigorous evaluation of transfer roughness.

[0193] After printing 1,000 sheets of images with a print ratio of 1.0% using evaluation paper CS-680, the toner amount was 0.40 mg / cm 2 The solid image was output onto evaluation paper CS-680 and Multi-Purpose Paper.

[0194] Furthermore, after printing 24,000 images with a printing ratio of 1.0% using evaluation paper CS-680, the toner loading amount was 0.40 mg / cm 2 The solid image was printed onto Multi-Purpose Paper.

[0195] Images on evaluation papers with different smoothness after 1000 sheets were printed, and images on evaluation paper with low smoothness after 25000 sheets were printed (after durability testing) were visually observed, and transfer roughness was evaluated based on the following criteria. Note that in this disclosure, areas where image uniformity was impaired were judged to be transfer roughness. A: No transfer marks are visible under normal light or when held up to a strong light. B: Almost no transfer marks are visible under normal light or when held up to a strong light. C: No transfer lumps are visible under normal light, but when held up to a strong light, transfer lumps are visible. D: Even under normal light, one or two transfer spots are visible, but no white spots are visible. E: Even under normal light, there are 3-4 transfer spots, but no white spots. F: Even under normal light, there are five or more areas where transfer defects are visible, or there is one or more areas where white spots are visible. A grade of D or higher was judged as good, and a grade of B or higher (B or A) was judged as even better.

[0196] (3) Transfer dust evaluation In a low temperature and humidity environment (15°C / 10%RH), the paper was printed on Letter size Business 4200 paper (Xerox, 75g / m 2 ) a grid pattern with lines 100 μm thick (thickness in the electrostatic latent image) spaced 1 cm apart was printed. The grid pattern image was observed using a 25x magnifying glass, and the transfer dust was evaluated based on the following criteria. A grade of B or above was considered good. A: The lines are very sharp and there is almost no transfer dust. B: There is only a slight scattering of toner, and the lines are sharp. C: There is a little bit of toner scattering, but the lines are relatively sharp. D: There is a lot of toner scattering and the lines are blurred.

[0197] (4) Graininess of halftone images Printed on Letter size Business 4200 paper (Xerox, 75 g / m²) in a high temperature and humidity environment (30°C / 80% RH). 2 ) was visually observed to evaluate the graininess (roughness) of the image according to the following criteria. A grade of B or above was considered good. A: It doesn't feel rough at all and is very smooth. B: I don't feel it is very rough. C: Slightly rough feeling. D: There is a clear feeling of roughness.

[0198] [Table 1-1] In the table, for silica particles 1 to 7, the substrate BET / m 2 / g column indicates the BET specific surface area of ​​200 m 2 / g small particle silica and 50m 2 This indicates that the large particle silica particles were used in a mass ratio of 10:1 (6:1 for Silica Microparticles 7) and 10:1 for small particle silica particles and large particle silica particles. In the example using hexamethyldisilazane, the number of parts is shown.

[0199] [Table 1-2] In the column for the presence or absence of (1), if a fragment ion corresponding to the structure shown in formula (1) is observed by TOF-SIMS, enter "Yes." And ZZ x 10 -4 is ZZ x 10 -3 For example, 15×10 -4 is 1.5 x 10 -3 is synonymous with.

[0200] [Table 2-1]

[0201] [Table 2-2] No polyvalent metal elements were detected in toner particle 17. Polyvalent metal elements were present on the surface of toner particles 1 to 16. The particle size is the weight average particle size (D4). The polyvalent metal element content is the content of the polyvalent metal element measured by the methods described in measurement methods (a) to (c).

[0202] [Table 3]

[0203] The present disclosure relates to the following configurations. (Configuration 1) A toner comprising toner particles 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: TIFF0007822866000012.tif37153 In the formula (1), n ​​represents an integer of 1 or more, When 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 mass % NaCl aqueous solution and titrated with sodium hydroxide, Sn, defined as Sn={(ab)×c×NA} / (d×e), satisfied 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 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 microparticles, 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, the area of ​​the peak whose top exists in the range of -25 to -15 ppm is defined as D, the sum of the areas of the peaks of M unit, D unit, T unit, and Q unit existing 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 5.7×10 -4 ~4.9×10 -3 and The silica particles were washed with chloroform and then measured for (D / S) / B of 1.7 x 10-4 ~4.9×10 -3 and When the area of ​​the peak having a peak top in the range of more than -19 ppm and not more than -17 ppm in the chemical shift is defined as D1, The ratio of D1 to D (D1 / D) is 0.10 to 0.30, at least one polyvalent metal element selected from the group consisting of calcium, magnesium, aluminum, and iron is present on the surface of the toner particles; The toner is characterized in that the total content of the polyvalent metal elements measured by the following measurement methods (a) to (c) is 1 to 2000 ppm by mass. (Measurement method) (a) 50.0 mg of the toner particles are stirred with 5.00 g of a 6.0 mol / L aqueous solution of nitric acid to extract the polyvalent metal elements on the surfaces of the toner particles. (b) The extract from which the polyvalent metal elements have been extracted is filtered to prepare a measurement sample. (c) The measurement sample is measured using an inductively coupled plasma mass spectrometer to determine the content of the polyvalent metal element based on the mass of the measurement sample. (Configuration 2) When the polyvalent metal element contains calcium, the content of calcium measured by any of the measurement methods (a) to (c) is 1 to 200 ppm by mass, When the polyvalent metal element contains magnesium, the content of the magnesium measured by any of the measurement methods (a) to (c) is 2 to 400 mass ppm, When the polyvalent metal element contains aluminum, the content of aluminum measured by any of the measurement methods (a) to (c) is 5 to 1000 ppm by mass, When the polyvalent metal element contains iron, the content of iron measured by the method described in the measurement methods (a) to (c) is 10 to 2000 mass ppm. 10. The toner according to claim 1. (Configuration 3) 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. (Configuration 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 %), 4. The toner according to any one of configurations 1 to 3, wherein the Ssi is 30 to 90 area %. (Configuration 5) 5. The toner according to any one of configurations 1 to 4, wherein the silica fine particles are surface-treated with at least a compound represented by the following formula (3): TIFF0007822866000013.tif37153 R in equation (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 the average number of repeating units and is an integer of 1 to 200. (Configuration 6) 6. The toner according to any one of configurations 1 to 5, wherein the carbon fixation rate when the silica fine particles are washed with chloroform is 30 to 70%. (Configuration 7) 7. The toner according to any one of configurations 1 to 6, wherein the silica fine particles are silica fine particles treated with cyclic siloxane and then treated with silicone oil.

Claims

1. A toner comprising toner particles 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, When 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 mass % NaCl aqueous solution and titrated with sodium hydroxide, Sn, defined as Sn = {(a-b) × c × NA} / (d × e), satisfied 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 the Si-NMR DD / MAS method, the area of ​​the peak whose top exists 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 existing 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 ~4.9 x 10 －３ and The silica fine particles were washed with chloroform, and then the (D / S) / B ratio measured was 1.7×10 －４ ~4.9 x 10 －３ and When the area of ​​a peak having a peak top in the range of more than −19 ppm to −17 ppm in the chemical shift is defined as D1, The ratio of D1 to D (D1 / D) is 0.10 to 0.30; at least one polyvalent metal element selected from the group consisting of calcium, magnesium, aluminum, and iron is present on the surface of the toner particles; The toner is characterized in that the total content of the polyvalent metal elements measured by the following measurement methods (a) to (c) is 1 to 2,000 ppm by mass. (Measurement method) (a) 50.0 mg of the toner particles are stirred with 5.00 g of a 6.0 mol / L aqueous solution of nitric acid to extract polyvalent metal elements from the surfaces of the toner particles. (b) The extract from which the polyvalent metal elements have been extracted is filtered to prepare a measurement sample. (c) The measurement sample is measured using an inductively coupled plasma mass spectrometer to determine the content of the polyvalent metal element based on the mass of the measurement sample.

2. When the polyvalent metal element contains calcium, the method described in the measurement methods (a) to (c) is the calcium content measured by a method is 1 to 200 ppm by mass, When the polyvalent metal element contains magnesium, the content of the magnesium measured by any of the measurement methods (a) to (c) is 2 to 400 ppm by mass, When the polyvalent metal element contains aluminum, the content of aluminum measured by any of the measurement methods (a) to (c) is 5 to 1000 ppm by mass, When the polyvalent metal element contains iron, the content of iron measured by the methods (a) to (c) is 10 to 2000 mass ppm. The toner according to claim 1 .

3. 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.

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. 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 the average number of repeating units and is an integer of 1 to 200.

6. 3. The toner according to claim 1, wherein the carbon fixation rate when the silica fine particles are washed with chloroform is 30 to 70%.

7. 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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