toner

Abstract

To provide a toner that has an excellent amount of electrification and electrification stability and can prevent fogging.SOLUTION: A toner contains a toner particle containing a binder resin and a mold release agent and silica fine particles on the surface of the toner particle. In measurement in time-of-flight secondary ion mass spectroscopy of the silica fine particles, fragment ions corresponding to the D-unit structure are observed. When the silica fine particles are dispersed in a mixed solution of ethanol and a NaCl solution and a titration operation using sodium hydroxide is performed, a titration amount falls within a specific range. In chemical shift obtained by solid 29Si-NMR of the silica fine particles, when the area of a peak where a peak top is present within a range from -25 to -15 ppm is defined as D, and the area of a peak where a peak top is present within a range exceeding -19 ppm and -17 ppm or less is defined as D1, D and D1 are present at a specific ratio. The mold release agent is present 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] 2. Description of the Related Art In recent years, as the purposes and environments of use of image forming apparatuses such as copying machines and printers have become more diverse, there has been a strong demand for higher speeds, higher image quality, and higher stability. However, as the speed of the device increases, the temperature of the device increases due to the high process speed, which tends to cause a decrease in image density and deterioration in image quality due to toner deterioration. The kneaded and pulverized toner particles containing a release agent have a good releasing effect even at high process speeds because the release agent is present on the surface of the toner. However, the release agent portion on the toner surface has a lower resistance than the resin portion on the toner surface, which makes it more likely that uneven charging will occur and the chargeability will decrease.

[0003] In response to this, a technology has been disclosed that suppresses uneven charging of the toner surface by externally adding silica particles whose surfaces have been hydrophobized with cyclic siloxane or dimethyl silicone oil, thereby enabling the production of high-resolution, high-quality images (Patent Document 1). In addition, a technology has been disclosed in which silica particles surface-treated with a specific amount or more of cyclic siloxane are used as an external additive to improve the charge build-up properties of the toner, thereby improving image quality and durability (Patent Document 2). In addition, a technology has been disclosed for surface-coated silica particles that retain a certain amount of free silicone oil by being coated with two or more types of silicone oil as an external additive, and this improves hydrophobicity, environmental stability of charging, and durability (Patent Document 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-114630 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-167029 [Patent Document 3] Japanese Patent Application Laid-Open No. 2007-176747 Summary of the Invention [Problem to be solved by the invention]

[0005] However, although the above-mentioned techniques are good to some extent in terms of charging characteristics and environmental stability, it has been found that there is still room for improvement in terms of improving the charging properties of toner containing toner particles having a release agent on the surface. It was found that the toners of Patent Documents 1 and 2 were inappropriately treated with cyclic siloxane or silicone oil. Therefore, while a certain degree of effect was observed in terms of initial environmental stability, the surface-treated silica particles were prone to deterioration with use, resulting in the exposure of hydrophilic groups on the surface of the silica particles. In particular, in high-temperature, high-humidity environments, a decrease in charging ability due to the influence of moisture was observed, and models with high print output were unable to achieve stable charging ability. Furthermore, it was found that the deterioration of the surface-treated silica particles was more pronounced in toners containing toner particles with a release agent present on the surface.

[0006] Furthermore, it was found that the amount of cyclic siloxane and silicone oil applied to the toner particles was inappropriate for the toner of Patent Document 3. As a result, although the toner has a certain effect on environmental stability, it is not very effective in improving the chargeability of the toner, and its fluidity is also low, so that in models that print a large number of pages, there is room for improvement in the charge stability during continuous use.

[0007] As described above, conventional silica coated with cyclic siloxane and silicone oil can impart unique charging properties to the silica. However, it has been found that it is becoming difficult to meet the charging stability that has been required in recent years, particularly in toners in which the release agent is exposed. That is, the present disclosure provides a toner that has excellent charge amount and charge stability and can suppress fogging, even when the toner contains toner particles on the surface of which a release agent is present. [Means for solving the problem]

[0008] As a result of extensive research, the present inventors have found that the above problems can be solved by the toner described below, and have come to the present disclosure. That is, the present disclosure provides a toner containing toner particles containing a binder resin and a release agent, 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, 2.00 g of the silica fine particles were dispersed in a mixed solution of 25.0 g of ethanol and 75.0 g of a 20% by mass aqueous solution of NaCl, and titration with sodium hydroxide was carried out. Sn defined as Sn={(ab)×c×NA} / (d×e) satisfies the following formula (2): 0.05≦Sn≦0.20 (2) In the formula (2), a is the titer (L) of NaOH required to adjust the pH of the mixture in which the silica fine particles are dispersed to 9.0, b is the titer (L) of NaOH required to adjust a 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 29In 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 ​​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; The toner has the release agent on the surface of the toner particles. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to provide a toner that has excellent charge amount and charge stability and can suppress fogging, even when the toner contains toner particles having a release agent on the surface. DETAILED DESCRIPTION OF THE INVENTION

[0010] 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.

[0011] First, toner particles containing a release agent on the surface have a release agent portion where part of the release agent is exposed, so that a good release effect can be easily obtained even at high process speeds. This phenomenon is particularly noticeable in high-speed machines. The reason for this is believed to be the amount of heat given to the toner layer developed on the paper surface. As the speed of the machine increases, the amount of heat from the fixing device is less easily transferred to the toner layer on the paper surface, and this tends to result in more toner that is insufficiently melted. In other words, the amount of release agent exuded from the inside of the toner is insufficient. Therefore, good release performance can be achieved by exposing the release agent on the toner surface.

[0012] However, the release agent portion on the toner surface has a lower resistance than the resin portion on the toner surface, which makes charging uneven and reduces the chargeability, especially in high-temperature, high-humidity environments. As a result of extensive research conducted by the present inventors with the aim of improving the charging properties of the toner particles, they discovered that this problem can be solved by combining the following silica fine particles with the toner particles, leading to the present disclosure.

[0013] The silica fine particles of the present disclosure will now be described. First, the inventors focused on the surface of silica fine particles. The surface of silica fine particles is hydrophilic because it contains hydroxyl groups (OH groups) contained in the silanol structure, i.e., silanol groups. Therefore, the surface of silica fine particles is prone to adsorb moisture in the air. Therefore, particularly in high-temperature, high-humidity environments, a decrease in chargeability due to moisture adsorption is likely to occur. However, simply increasing the amount of surface treatment on the silica particle substrate to reduce the surface silanol groups of silica particles does not fully control the amount of silanol, and no improvement in charging performance is observed under high-temperature, high-humidity environments.Furthermore, the fluidity of the toner decreases, and image defects such as streaks and haze due to toner aggregation occur.

[0014] As a result of extensive research by the present inventors into external additives that can improve chargeability, stabilize chargeability, and enable image output without adverse effects, it was found that it is effective for the surface treatment component of the silica fine particles to have a polydimethylsiloxane structure, and for the amount of dimethylsiloxane in the surface treatment structure 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 end of the surface treatment structure to be appropriately controlled.

[0015] That is, the present disclosure provides a toner containing toner particles containing a binder resin and a release agent, 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, 2.00 g of the silica fine particles were dispersed in a mixed solution of 25.0 g of ethanol and 75.0 g of a 20% by mass aqueous solution of NaCl, and titration with sodium hydroxide was carried out. Sn defined as Sn={(ab)×c×NA} / (d×e) satisfies the following formula (2): 0.05≦Sn≦0.20 (2) In the formula (2), a is the titer (L) of NaOH required to adjust the pH of the mixture in which the silica fine particles are dispersed to 9.0, b is the titer (L) of NaOH required to adjust a 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 ​​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; The toner has the release agent on the surface of the toner particles.

[0016] The reasons why controlling the surface treatment state of silica fine particles (formula (2), (D / S) / B and D1 / D) can improve the charge amount, obtain charge stability, and suppress fogging even in toners containing toner particles with a release agent on the surface are explained below.

[0017] 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]

[0018] (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.

[0019] The amount of Si-OR groups (R is a hydrogen atom, a methyl group, or an ethyl group) in the silica fine particles is the sum of the amount of Si-OR groups on the surface of the silica fine particle substrate and in the surface-treated structure of the silica fine particles, i.e., D1, which will be described later. The Si-OR groups are polarized, and the Si-O δ- R δ+ Because of the polarity of the Si-OR groups, it is believed that the chargeability of silica microparticles is controlled by the content of Si-OR groups. If the amount of Si-OR is small, chargeability cannot be obtained. Furthermore, if the amount of Si-OR is excessive, chargeability tends to decrease, especially in high-temperature, high-humidity environments. Among the Si-OR groups, the silanol groups on the surface of the silica substrate are prone to adsorb moisture, and are therefore thought to contribute significantly to the deterioration of chargeability. That is, the amount of silanol groups on the surface of the silica fine particle substrate and in the surface-treated structure of the silica fine particles must be appropriate.

[0020] 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).

[0021] When Sn satisfies the formula (2), it means that the amount of silanol groups on the surface of the silica fine particle substrate and in the surface-treated structure of the silica fine particles is appropriate. This improves the chargeability of the toner. Sn is preferably 0.05 to 0.17, and more preferably It is 0.07 to 0.15. When the content is in the above range, the toner is in a state where it is not easily affected by moisture in the environment, and even in the toner in which the release agent is exposed, the effect of improving the chargeability can be obtained, and fogging can be suppressed. Sn can be increased by treating the silica microparticle substrate under conditions that prevent the reaction of the surface treatment agent so that silanol 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.

[0022] 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.

[0023] 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.

[0024] 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 the silica microparticles have been 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 M unit, D unit, and T unit show peaks corresponding to the structure of the surface treatment agent of the silica microparticles represented by the above formulas (4) to (6), respectively. Both are solid 29Identification 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.

[0025] Silica fine particle solid 29 In the chemical shift obtained by Si-NMR DD / MAS, 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 unit, D unit, T unit, and Q unit that are in the range of -140 to 100 ppm is defined as S. In this case, the BET specific surface area of ​​the silica fine particles after surface treatment is defined as B (m 2 / g), then (D / S) / B is 5.7×10 -4 ~4.9×10 -3 is. The parameter (D / S) / B means the Si atomic weight per unit surface area constituting the D unit relative to the Si atomic weight of the entire silica microparticle. 29 In Si-NMR measurements, silica particles with a peak in the D unit are represented by compounds with a dimethylsiloxane structure. This indicates that the surface has been treated.

[0026] In other words, the parameter (D / S) / B represents the amount of dimethylsiloxane on the surface of silica particles per unit surface area. The smaller the (D / S) / B, 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 substrate, the effects of moisture in high-temperature, high-humidity environments cannot be suppressed, and the improvement in electrostatic charge is small. Conversely, the larger the (D / S) / B ratio, the greater the amount of dimethylsiloxane on the surface of the silica microparticles. However, an excess of D units acts as an external additive, inhibiting fluidity, which also tends to reduce chargeability. Furthermore, if the dimethylsiloxane treatment is uneven, silanol groups remain on the surface of the silica microparticle substrate, which can lead to a decrease in chargeability when printing a large number of pages, especially in high-temperature, high-humidity environments.

[0027] Therefore, (D / S) / B is 5.7×10 -4 ~4.9×10 -3 It is necessary that (D / S) / B is 5.7×10 -4 If the (D / S) / B ratio is less than 4.9×10, the dimethylsiloxane treatment is insufficient, and the toner charging property significantly decreases in a high-temperature, high-humidity environment. -3 If the ratio (D / S) / B is more than 6.2×10, the amount of dimethylsiloxane becomes excessive, and the fluidity of the toner is significantly reduced. -4 ~4.9×10 -3 Preferably, it is 7.1 × 10 -4 ~4.9×10 -3 More preferably, it is 8.1 × 10 -4 ~4.9×10 -3 It is more preferable that: (D / S) / B can be increased by increasing the amount of surface treatment agent used in the surface treatment of the silica fine particle substrate or by using a surface treatment agent that contains a large amount of components having a polydimethylsiloxane structure, while (D / S) / B can be decreased by decreasing the amount of surface treatment agent used in the surface treatment of the silica fine particle substrate or by using a surface treatment agent that does not contain a large amount of components having a polydimethylsiloxane structure.

[0028] 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. The (D / S) / B ratio measured after washing the silica particles with chloroform was 1.7 × 10 -4 ~4.9×10 -3The washing operation removes the physically adsorbed surface treatment agent, leaving only the chemically bonded surface treatment agent. Therefore, after washing, (D / S) / B indicates the amount of chemically bonded D units. If (D / S) / B is 1.7 x 10 -4 If the surface treatment agent is less than 4.9×10, the amount of the surface treatment agent adhering to the surface of the silica particles will be insufficient, and the surface treatment agent may peel off during long-term use, making it impossible to prevent moisture adsorption in a high-temperature, high-humidity environment. -3 If it is larger, the fluidity of the toner tends to decrease, and the chargeability decreases. After washing the silica particles with chloroform, the (D / S) / B ratio is preferably 2.5×10 -4 ~3.2×10 -3 and more preferably 7.0 × 10 -4 ~1.4×10 -3 is.

[0029] Here, the polar group at the end of the structure derived from the surface treatment agent for the silica fine particles is defined as D1. 29 This corresponds to a peak whose top is in the range of more than -19 ppm to -17 ppm in the chemical shift obtained by Si-NMR. In the silica fine particles treated with D units, D1 means a polar group at the end of the D unit and has a structure represented by the following formula (8). D1: -Si-OR 3 ···(8) (R in Equation (8) 3 is a methyl group, an ethyl group, or a hydrogen atom.

[0030] As a result of extensive research by the present inventors, it has been found that when silica fine particles have an appropriate amount of polar groups at the terminals of the D units, the chargeability of toner particles containing a release agent on the surface is improved. I knew it would go up. The inventors speculate on the effect of the polar group at the end of the D unit as follows: Compared to polar groups such as silanol groups in the Q unit present on the surface of the silica microparticle substrate, the polar group D1 at the end of the D unit has a moderately high hydrophobicity. This is thought to be due to the hydrophobicity derived from the carbon atom bonded to the Si to which the polar group is bonded. The polar group D1 at the end of the D unit, which has moderately high hydrophobicity, is polarized, and the oxygen atom in the Si-OR group carries a negative charge δ - As a result, the ends of the structures derived from the surface treatment agent have high electron donating properties, which has the effect of imparting electrostatic charge to the hydrophobic group ends. In addition, D1 at the D unit end is more hydrophobic than the silanol groups present on the surface of the silica microparticle substrate, so the silica microparticles are less affected by moisture, making it easier to maintain good electrostatic charge. Furthermore, as shown by (D / S) / B after washing with chloroform, the D units are bonded to the silica microparticle substrate to a certain extent, and D1 at the end of the D units is located away from the surface of the silica microparticle substrate. Therefore, the Si-OH group of D1 is less susceptible to the influence of moisture on the silica microparticle substrate than the silanol groups present on the surface of the silica microparticle substrate, making it easier to maintain good chargeability.

[0031] Therefore, the surface of the silica particles is treated with a treatment agent containing D units to control the amount of silanol groups on the surface of the silica particles to an appropriate level, and a certain amount of D1 is introduced at the end of the D units. In other words, (D / S) / B, (D / S) / B after washing with chloroform, and D1 / D are set to appropriate ranges. By satisfying these requirements, the charge amount can be improved even in high-temperature, high-humidity environments.

[0032] Furthermore, it is believed that the adhesion state of the silica fine particles to the release agent portion on the surface of the toner particles changes because the surface-treated silica fine particles partially retain D1 at the D unit terminals. This is thought to be because the partial presence of D1 at the D unit terminals reduces the coefficient of friction between the release agent portion on the surface of the toner particles and the silica fine particles, resulting in good adhesion between the release agent portion and the silica fine particles. Therefore, by controlling the amount of D1 in the silica fine particles, it is thought that in toners containing toner particles with a release agent on their surface, the separation of silica fine particles from the toner and their embedding in the toner due to durability is suppressed, further improving charging stability.

[0033] Silica fine particle solid 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. The ratio of D1 to D (D1 / D) is 0.10 to 0.30. If D1 / D is less than 0.10, the amount of polar groups is small, which tends to reduce the adhesion of silica fine particles to the release agent portion on the surface of the toner particles, and the charging improvement effect cannot be obtained. Also, if D1 / D is greater than 0.30, the amount of polar groups is too large, which increases the influence of moisture, particularly in high-temperature, high-humidity environments, resulting in reduced charging performance. Also, fogging increases. D1 / D is more preferably 0.10 to 0.25, and even more preferably 0.15 to 0.25. D1 / D can be increased by increasing the content of silanol or cyclic siloxane in the treatment agent components used in the surface treatment of the silica fine particle substrate, while D1 / D can be decreased by decreasing the content of silanol or cyclic siloxane in the treatment agent components used in the surface treatment of the silica fine particle substrate.

[0034] solid 29The peak of the D unit obtained by Si-NMR DD / MAS is separated into two peaks. The area of ​​the peak with its top in the chemical shift range of more than -19 ppm to -17 ppm is defined as peak D1, and the area of ​​the peak with its top in the chemical shift range of -23 to -19 ppm is defined as peak D2. Among the D units measured in silica fine particles, the Si atoms bonded to the OR groups at the ends of the D units are It is known that peak D1 corresponds 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 polar groups there are at the ends of the D units. In other words, D1 / D indicates the amount of polar groups in the D units of the treatment agent. The larger D1 / D, the more polar groups there are at the ends of the D units.

[0035] The toner particles contain a release agent, and the release agent is present on the surface of the toner particles. When the ratio of the release agent on the surface of the toner particles is Sw (area %), Sw is preferably 10 to 70 area %. The ratio of the release agent on the surface of the toner particles can be measured by electron staining SEM observation, which will be described later. If the release agent content (Sw) is 10% or more by area, the amount of melted and exuded release agent is sufficient during the fixing process, resulting in effective release, preventing offset and improving image density. If Sw is 70% or less by area, the release agent itself has low resistance, and in addition to low charging properties, the silica fine particles externally added to the surface of the toner particles are less likely to be embedded in the release agent, improving fluidity and making it easier to suppress fogging and streaks caused by toner aggregation. Sw is preferably 35 to 60 area %, and more preferably 40 to 55 area %. When Sw is 35 area % or more, the release agent can be sufficiently melted and exuded during the fixing process, so that a good release effect can be obtained even at a high process speed. When Sw is 60 area % or less, the charge improvement property of the silica fine particles can be effectively obtained. The content of the release agent can be controlled by adjusting the content of the release agent in the toner particles and the toner production conditions.

[0036] When the coverage rate of silica fine particles on the surface of a toner particle, Ssi (area %), calculated from an image of the toner surface observed by a scanning electron microscope, is taken as Ssi, it is preferably 25 to 90 area %, more preferably 30 to 80 area %, further preferably 35 to 60 area %, and particularly preferably 40 to 55 area %. When the Ssi is 25% by area or more, charging unevenness due to the release agent exposed on the toner surface can be suppressed, and good fluidity and chargeability can be imparted. Also, when the Ssi is 90% by area or less, a sufficient amount of heat is transmitted to the toner during the fixing process, so that the release effect is fully exerted and low-temperature fixability can be obtained. Ssi can be controlled by the amount of silica fine particles added to the toner particles.

[0037] The ratio (Sw / Ssi) of the release agent abundance rate (Sw) on the toner particle surface to the silica fine particle coverage rate (Ssi) is preferably 0.18 to 2.80, more preferably 0.40 to 2.40, even more preferably 0.70 to 2.33, particularly preferably 0.85 to 2.10, and even more preferably 0.88 to 1.35. By making Sw / Ssi 0.18 or more, it is possible to achieve both the low-temperature fixing effect due to the release agent exposure and the chargeability improvement effect due to the surface-treated silica. Also, when Sw / Ssi is 2.80 or less, the coverage rate of silica fine particles relative to the presence rate of the release agent on the surface of the toner particles is appropriate, and charge stability can be further improved.

[0038] 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 carbon fixation rate is considered to correspond to the amount of the surface treatment agent chemically bonded or firmly physically bonded to the surface of the silica substrate. By controlling the carbon fixation rate of the silica particles using the surface treatment agent within the above range, The crushability and friction coefficient between silica fine particles can be controlled within appropriate ranges. Furthermore, similar properties can be imparted to toner to which these silica fine particles are externally added, improving chargeability. Furthermore, when the C content fixation rate is high and the treated surface is maintained, adhesion between the release agent portion on the surface of the toner particles and the silica fine particles is good, improving the durability and charge stability of the toner.

[0039] The content of the silica fine particles is preferably 0.2 to 2.2 parts by mass, more preferably 0.3 to 2.0 parts by mass, even more preferably 0.4 to 2.0 parts by mass, and particularly preferably 0.7 to 1.5 parts by mass, relative to 100 parts by mass of the toner particles. By setting the content of the silica fine particles within the above range, it is possible to exhibit an effect of improving the chargeability without inhibiting the release effect of the release agent on the surface of the toner particles.

[0040] 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 15 to 25 nm. By externally adding silica fine particles having a particle size within this range to toner particles, toner properties such as the chargeability and fluidity of the toner can be adjusted to obtain good development properties, and the fluidity and chargeability imparted to the toner can be easily maintained throughout durability.

[0041] The silica fine particles preferably contain small silica fine particles and large silica fine particles. The number average particle size of the small silica fine particles is preferably 5 to 25 nm, more preferably 10 to 25 nm, and the number average particle size of the large silica fine particles is preferably more than 25 nm but not more than 55 nm, more preferably 30 to 40 nm. The BET specific surface area of ​​small silica particles is 100 to 500 m 2 / g, and 150 to 300m 2 / g. The BET specific surface area of ​​the large particle silica particles is preferably 10 to 100 m 2 / g, and 30 to 80m 2 / g is more preferred. The mass ratio of small silica particles to large silica particles is preferably 20:1 to 5:1, more preferably 15:1 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.

[0042] It has been confirmed that toners to which small silica particles have been externally added have small silica particles embedded in the surface of the toner particles. This is due to, for example, stress from the carrier when used as a two-component developer, stress from the developing blade and developing sleeve when used as a one-component developer, and collisions with the inner wall of the developing device, the toner stirring blade, and between toner particles. In order to reduce the embedding of the small silica particles, it is effective to contain both small and large silica particles as described above. Large silica particles act as spacer particles, preventing the toner surface with small silica particles from coming into direct contact with the carrier, developing blade, developing roller, inner wall of the developing unit, toner stirring members, other toner particles, etc. This reduces stress. This prevents the small silica particles from being embedded in the surface of the toner particles, thereby achieving a longer toner life. The number-average particle size of the silica microparticles can be controlled by changing the conditions in the manufacturing process of the silica microparticles, such as the classification process, and can also be controlled by adjusting the mixing ratio of small-diameter silica microparticles and large-diameter silica microparticles, and the number-average particle size of each.

[0043] It is more preferable that the silica fine particles are surface-treated with at least a compound represented by the following formula (3). [ka]

[0044] 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).

[0045] The surface treatment agent of formula (3) can further improve the charge stability in a high-temperature, high-humidity environment. The surface treatment agent used is not particularly limited as long as it is a compound represented by formula (3), and known compounds can be used. These may be used alone or in combination of two or more. Two or more surface treatment agents having different functional groups may be used sequentially or in admixture, or two or more surface treatment agents having the same functional group but different viscosities or molecular weight distributions may be used sequentially or in admixture. Whether or not the surface has been treated with the compound represented by formula (3) can be determined by a method such as analyzing the mass spectrum obtained by gas chromatography-mass spectrometry.

[0046] The toner preferably contains strontium titanate fine particles on the surface of the toner particles in addition to silica fine particles. The elemental intensity ratio (Si / Sr) of the content of silica fine particles to the content of strontium titanate fine particles in the toner determined by fluorescent X-ray analysis is preferably 0.10 to 2.30, more preferably 0.10 to 1.50, and even more preferably 0.10 to 0.80. The presence of strontium titanate microparticles on the surface of the toner particles has the effect of polishing and removing deposits from parts inside the device, and the strontium titanate microparticles also act as microcarriers, further improving the charging performance of the toner. By controlling the Si / Sr ratio within the above range, both cleaning performance and charging stability can be achieved. The content ratio of silica fine particles to strontium titanate fine particles is calculated from the signal intensity ratio of Si atoms obtained by fluorescent X-ray analysis of the toner to the signal intensity of Sr atoms in the strontium titanate fine particles. The measurement method for fluorescent X-ray analysis will be described later. The Si / Sr ratio can be controlled by the amount of silica particles or strontium titanate particles added externally.

[0047] The content of the strontium titanate fine particles is preferably 0.01 to 0.70 parts by mass, more preferably 0.02 to 0.33 parts by mass, even more preferably 0.02 to 0.30 parts by mass, and particularly preferably 0.10 to 0.25 parts by mass, relative to 100 parts by mass of toner particles. By setting the amount within the above range, both cleaning performance and charging stability can be achieved.

[0048] The toner particles contain a release agent. The release agent is not particularly limited, and any known release agent can be used. Specifically, petroleum waxes such as paraffin wax, microcrystalline wax, petroleum waxes and their derivatives, montan wax and its derivatives, hydrocarbon waxes and their derivatives produced by the Fischer-Tropsch process, polyethylene, polypropylene substitutes, etc. Examples of suitable waxes include polyolefin waxes and their derivatives, natural waxes such as carnauba wax and candelilla wax, and ester waxes. The derivatives include oxides, block copolymers with vinyl monomers, and graft-modified products. Examples of suitable ester waxes include monofunctional ester waxes, difunctional ester waxes, and polyfunctional ester waxes such as tetrafunctional and hexafunctional ester waxes. Among these, at least one selected from the group consisting of hydrocarbon waxes and ester waxes is preferred. The type of release agent in the toner particles can be identified by extracting the release agent components in the toner particles with a general-purpose solvent and then analyzing the mass spectrum obtained by gas chromatography mass spectrometry.

[0049] The content of the release agent is preferably 0.1 to 15.0 parts by mass, more preferably 0.5 to 15.0 parts by mass, even more preferably 1.0 to 11.0 parts by mass, and particularly preferably 2.0 to 8.0 parts by mass, relative to 100 parts by mass of the binder resin. By setting the amount of the toner in the above range, it is possible to obtain a good charge amount and charge stability of the toner and to suppress fogging. The content of the release agent can be calculated by extracting the binder resin and the release agent components from the toner particles with a general-purpose solvent, separating them from the inorganic components by a centrifugal separation method or the like, and then solvent-extracting them again with a solvent in which the release agent components are insoluble, and measuring the weights of the dried binder resin and the released agent components.

[0050] The silica fine particles are preferably hydrophobized silica particles obtained by heat-treating a silica fine particle base together with a cyclic siloxane and then heat-treating it with silicone oil. That is, the silica fine particles are preferably silicone oil-treated silica fine particles that have been treated with a cyclic siloxane. When the amount of cyclic siloxane treated per 100 parts by mass of silica fine particles is X parts by mass and the amount of silicone oil treated is Y parts by mass, the ratio of X to Y (X / Y) is preferably 0.60 to 1.20, more preferably 0.62 to 1.15, and even more preferably 0.70 to 1.00. By controlling X / Y within the above range, the value of D1 / D can be controlled within the target range.

[0051] 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.

[0052] 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.

[0053] The silica particles used are silica substrates that have been surface-treated to impart hydrophobicity and fluidity. Surface treatment methods include chemical treatment with a silicon compound that reacts with or physically adsorbs to the silica substrate. The method for surface treatment of the silica fine particle substrate is not particularly limited, and can be carried out by contacting a surface treatment agent containing siloxane bonds with the silica fine particles. From the viewpoint of uniformly treating the surface of the silica fine particle substrate and easily achieving the above-mentioned physical properties, it is preferable to contact the silica fine particle substrate with the surface treatment agent in a dry state. As will be described later, there are methods of contacting the vapor of the surface treatment agent with the silica fine particle base material, or spraying the undiluted solution of the surface treatment agent or a diluted solution with various solvents. For example, the method may involve contacting the silica fine particle substrate.

[0054] 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 dry-treating the silica fine particle substrate with a cyclic siloxane, and a second treatment step of dry-treating the silica fine particle substrate after the cyclic siloxane treatment with silicone oil. The silica fine particles are preferably silicone oil-treated products of silica fine particles treated with the cyclic siloxane. The toner production method preferably includes a step of preparing the silica fine particles obtained by the above method.

[0055] 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 applying cyclic siloxane to the surface of the silica microparticle substrate is preferably 300°C or higher. By setting the temperature at 300°C or higher, the silanol groups on the surface of the silica microparticle substrate can be effectively reduced. Furthermore, by setting the treatment temperature at 300°C or higher, siloxane bonds are generated and broken, making it possible to treat the surface of the silica microparticle substrate more uniformly while uniformly controlling the chain length of the siloxane. The treatment temperature of the cyclic siloxane on the surface of the silica fine particle substrate 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.

[0056] 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. There is no particular upper limit, but it is preferably 380°C or lower, 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 a small surface treatment amount without reducing its fluidity and improves its charging stability.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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. Specifically, styrene-based 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, polyvinyl acetate, etc. can be used alone or in combination of two or more. Among these, styrene-based copolymers and polyester resins are particularly preferred in terms of development characteristics, fixability, etc.

[0061] It is preferable to add a charge control agent 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.).

[0062] 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).

[0063] 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.

[0064] 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. Specifically, petroleum waxes such as paraffin wax, microcrystalline wax, and petroleum waxes and their derivatives, montan wax and its derivatives, hydrocarbon waxes produced by the Fischer-Tropsch process and their derivatives, polyolefin waxes such as polyethylene and polypropylene and their derivatives, natural waxes such as carnauba wax and candelilla wax and their derivatives, and ester waxes. Here, the derivatives include oxides, block copolymers with vinyl monomers, and graft-modified products. Furthermore, as the ester wax, monofunctional ester waxes, difunctional ester waxes, and polyfunctional ester waxes such as tetrafunctional and hexafunctional ester waxes can be used.

[0065] The melting point of the release agent is preferably 60 to 140° C., more preferably 70 to 130° C. When the melting point is 60 to 140° C., the toner is easily plasticized during fixing, improving fixability. In addition, when the melting point is in the above range, bleeding of the release agent is unlikely to occur even when stored for a long period of time, which is preferable.

[0066] 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. Cyan colorants include copper phthalocyanine compounds and their derivatives, anthraquinone compounds, and basic dye lake compounds, specifically CI Pigment Blue 1, 7, 15, 15:1, 15:2, 15:3, 15:4, 60, 62, and 66.

[0067] 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. Examples of yellow colorants include condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds. Specific examples include 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.

[0068] Examples of black colorants include carbon black, as well as the above-mentioned yellow colorants, magenta colorants, and cyan colorants, and those toned to black using magnetic materials. These colorants can be used alone or in combination, or in the form of a solid solution. The colorants used in the present disclosure are selected in consideration of hue angle, chroma, brightness, lightfastness, transparency on overhead projectors (OHPs), and dispersibility in toner particles.

[0069] When a magnetic material is used as a colorant in a toner, the magnetic material is composed mainly of magnetic iron oxide such as iron oxide trioxide or γ-iron oxide, and may contain elements such as phosphorus, cobalt, nickel, copper, magnesium, manganese, aluminum, and silicon. These magnetic materials have a BET specific surface area of ​​2 to 30 m2 as measured by a nitrogen adsorption method. 2 / g, and 3 to 28m 2 / g. Also, the Mohs hardness is preferably 5 to 7. The shape of the toner particles may be polyhedron, octahedron, hexahedron, sphere, needle-like, scale-like, etc., but those with less anisotropy such as polyhedron, octahedron, hexahedron, and sphere are preferred in terms of increasing image density.

[0070] The amount of colorant added is preferably 1 part by mass or more and 20 parts by mass or less relative to 100 parts by mass of the binder resin or the polymerizable monomer that constitutes the binder resin. When magnetic powder is used, the amount is preferably 20 parts by mass or more and 200 parts by mass or less, more preferably 40 parts by mass or more and 150 parts by mass or less relative to 100 parts by mass of the binder resin or the polymerizable monomer that constitutes the binder resin.

[0071] The toner may contain, in addition to silica fine particles and strontium titanate fine particles, other external additives such as inorganic fine particles other than silica fine particles and strontium titanate fine particles. The toner can be obtained by externally adding silica fine particles, strontium titanate fine particles, and, if necessary, inorganic fine particles other than silica fine particles and strontium titanate fine particles to toner particles as external additives. Examples of inorganic fine particles include hydrotalcite compounds, fatty acid metal salts, alumina, and metal oxide fine particles (inorganic fine particles) such as titanium oxide, zinc oxide fine particles, cerium oxide fine particles, and calcium carbonate fine particles.

[0072] Furthermore, as other external additives, composite oxide fine particles using two or more types of metals can be used, or two or more types selected from these fine particle groups in any combination can be used. Furthermore, resin fine particles and organic-inorganic composite fine particles of resin fine particles and inorganic fine particles can also be used.Preferably, the toner contains titanium oxide particles in addition to silica fine particles as an external additive. The other external additives may be subjected to a hydrophobic treatment with a hydrophobic treatment agent.

[0073] 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-methylphenyltrimethoxysilane, p-methylphenyltrimethoxysilane, n-butyltrimethoxysilane, i-butyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, dodecyltrimethoxysilane, tetraethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, i-butyl Alkoxysilanes such as ethyltriethoxysilane, 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.

[0074] 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 external additives is preferably 0.05 to 20.0 parts by mass relative to 100 parts by mass of toner particles. The content of the external additives other than the silica fine particles and the strontium titanate fine particles is preferably 0.1 to 1.0 part by mass, more preferably 0.1 to 0.5 part by mass, relative to 100 parts by mass of toner particles.

[0075] The weight average particle diameter (D4) of the toner is preferably 3.0 to 12.0 μm, more preferably 4.0 to 10.0 μm. When the weight average particle diameter (D4) is in the above range, good fluidity is obtained, and the latent image can be developed faithfully.

[0076] The method for producing the toner is not particularly limited, and any known production method can be used, including a pulverization method, a polymerization method, a dispersion polymerization method, an association aggregation method, a solution suspension method, a suspension polymerization method, and an emulsion aggregation method. Specific examples of the pulverization method for producing a toner through a melt-kneading step and a pulverization step will be given below, but the method is not limited to these.

[0077] For example, a binder resin and, if necessary, a colorant, a release agent, a charge control agent, and other additives are thoroughly mixed using a mixer such as a Henschel mixer or a ball mill (mixing step), and the resulting mixture is melt-kneaded using a thermal kneader such as a twin-screw kneading extruder, a heated roll, a kneader, or an extruder (melt-kneading step).

[0078] The resulting molten and kneaded product is cooled and solidified, then pulverized using a pulverizer (pulverization step), and classified using a classifier (classification step) to obtain toner particles. If necessary, the toner particles and external additives are mixed in a mixer such as a Henschel mixer to obtain a toner.

[0079] Examples of mixers include the following: FM Mixer (Nippon Coke and Engineering Co., Ltd.); Super Mixer (Kawata Corporation); Ribocone (Okawahara Manufacturing Co., Ltd.); Nauta Mixer, Turbulizer, Cyclomix (Hosokawa Micron Corporation); Spiral Pin Mixer (Pacific Ocean Machinery Works Co., Ltd.); and Lödige Mixer (Matsubo Corporation).

[0080] Examples of thermal kneaders include the following: KRC kneader (manufactured by Kurimoto Iron Works); Buss-Co kneader (manufactured by Buss); TEM type extruder (manufactured by Toshiba Machine Co., Ltd.); TEX twin-screw kneader (manufactured by The Japan Steel Works); PCM kneader (manufactured by Ikegai Iron Works); three-roll mill, mixing roll mill, kneader (manufactured by Inoue Manufacturing Co., Ltd.); Kneadex (manufactured by Mitsui Mining Co., Ltd.); M-second pressure kneader, Kneader-Ruder (manufactured by Moriyama Manufacturing Co., Ltd.); and Banbury mixer (manufactured by Kobe Steel, Ltd.).

[0081] Examples of the crusher include the following: Counter Jet Mill, Micron Jet, Innomizer (manufactured by Hosokawa Micron Corporation); IDS type mill, PJM jet crusher (manufactured by Japan Pneumatic Kogyo Co., Ltd.); Cross Jet Mill (Kurimoto Iron Works Co., Ltd.); Urmax (Nisso Engineering Co., Ltd.); SK Jet-O-Mill (Seishin Enterprise Co., Ltd.); Kryptron (Kawasaki Heavy Industries Co., Ltd.); Turbo Mill (Turbo Kogyo Co., Ltd.); Super Rotor (Nisshin Engineering Co., Ltd.).

[0082] Examples of classifiers include the following: Cruseal, Micron Classifier, and Spedic Classifier (manufactured by Seishin Enterprise Co., Ltd.); Turbo Classifier (manufactured by Nisshin Engineering Co., Ltd.); Micron Separator, Turboplex (ATP), and TSP Separator (manufactured by Hosokawa Micron Corporation); Elbow Jet (manufactured by Nittetsu Mining Co., Ltd.), and Dispersion Separator (manufactured by Nippon Pneumatic Mfg. Co., Ltd.); and YM Microcut (manufactured by Yaskawa Corporation).

[0083] In addition, the following sieving devices may be used to sieve out coarse particles: Ultrasonic (manufactured by Koei Sangyo Co., Ltd.); Resonaseave, Gyrosifter (manufactured by Tokuju Kogyosho Co., Ltd.); Vibrasonic System (manufactured by Dalton Co., Ltd.); Soniclean (manufactured by Shinto Kogyo Co., Ltd.); Turbo Screener (manufactured by Turbo Kogyo Co., Ltd.); Microsifter (manufactured by Makino Sangyo Co., Ltd.); and circular vibrating sieve.

[0084] By the suspension polymerization method, toner particles are produced, for example, as follows. A polymerizable monomer composition is prepared by uniformly dissolving or dispersing polymerizable monomers for forming a binder resin, such as a styrene-based monomer, a (meth)acrylic acid ester-based monomer, a colorant, a wax component, and a polymerization initiator, using a dispersing machine such as a homogenizer, a ball mill, an ultrasonic dispersing machine, etc. The polymerizable monomer composition is dispersed in an aqueous medium to granulate particles of the polymerizable monomer composition, and then the polymerizable monomer in the particles made of the polymerizable monomer composition is polymerized to obtain toner particles.

[0085] In this case, the polymerizable monomer composition is preferably one prepared by mixing a dispersion in which a colorant is dispersed in a first polymerizable monomer (or a part of the polymerizable monomer) with at least a second polymerizable monomer (or the remaining polymerizable monomer). That is, by first dispersing the colorant sufficiently in the first polymerizable monomer, and then mixing it with the second polymerizable monomer together with other toner materials, the colorant can be present in the polymer particles in a better dispersed state.

[0086] The resulting polymer particles are filtered, washed, dried, and classified by known methods to obtain toner particles. The toner can be obtained by externally adding and mixing silica fine particles to the toner particles obtained as described above.

[0087] The external addition of an external additive such as silica fine particles to toner particles can be carried out by mixing the toner particles and the external additive with a mixer such as the following. Examples of mixers include the following: Henschel mixer (manufactured by Mitsui Mining Co., Ltd.); Super mixer (manufactured by Kawata Corporation); Ribocone (manufactured by Okawara Manufacturing Co., Ltd.); Nauta mixer, Turbulizer, Cyclomix (manufactured by Hosokawa Micron Corporation); Spiral pin mixer (manufactured by Pacific Machinery Works Co., Ltd.); and Lödige mixer (manufactured by Matsubo Corporation).

[0088] From the viewpoint of dispersibility of the external additive, the mixing time in the external addition step is preferably adjusted to a range of 0.5 minutes or more and 10.0 minutes or less, 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.

[0089] Next, the measurement methods for each physical property will be described. <Silica fine particle solid 29 Calculation method for (D / S) / B and D1 / D using Si-NMR DD / MAS measurement Silica fine particle solid 29 The Si-NMR measurement is performed by separating the silica particles from the toner surface. Below, we will explain how to separate the silica particles from the toner surface and how to measure the solid state. 29 The Si-NMR measurements are described.

[0090] <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.

[0091] 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 the inorganic particle mixture from the lower layer. The obtained toner particles are used to measure the release agent content, 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.

[0092] 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. Next, the solid silica particles recovered from the toner particles 29 The Si-NMR measurement is carried out under the measurement conditions shown below.

[0093] <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)

[0094] After the above measurement, the solid of silica fine particles 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 )(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.

[0095] 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. In addition, the sum S of all integral values ​​of the M, D, T, and Q units present in the chemical shift range of -140 to 100 ppm is calculated, and the BET specific surface area B (m 2 / g) and calculate the ratio (D / S) / B. Also, calculate the ratio D1 / D from the integral values ​​of peaks D1 and D obtained by waveform separation. Furthermore, after the silica fine particles are washed with chloroform as described below, the same NMR measurement is carried out to calculate (D / S) / B after washing.

[0096] <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.

[0097] <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 mass profile of the secondary ion mass / secondary ion charge number (m / z) obtained, it is confirmed whether fragment ions corresponding to the structure represented by formula (1) are observed. For example, when the surface treatment agent is polydimethylsiloxane or cyclic siloxane, fragment ions are observed at positions such as m / z=147, 207, and 221.

[0098] <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 Specific 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 mand 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 )

[0099] 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. Place the sample cell containing the silica microparticles in a "pretreatment device VacuPrep 061 (Shimadzu Corporation)" connected to a vacuum pump and nitrogen gas piping, and continue vacuum degassing at 23°C for 10 hours. During vacuum degassing, the valve is adjusted to gradually 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.

[0100] 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.

[0101] 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

[0102] <Method for measuring the Si-OH content of silica fine 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)

[0103] <Method for calculating the coverage rate Ssi of silica fine particles on the surface of toner particles> The coverage rate Ssi of the silica particles on the surface of the toner particles is measured by scanning electron microscope (SEM). It is calculated from a backscattered electron image obtained by observation. Backscattered electron images are also called "composition images," with smaller atomic numbers being detected as darker and larger atomic numbers being brighter. A backscattered electron image of toner is obtained under the following observation conditions. Below, we will describe how to obtain a backscattered electron image of toner and how to calculate the coverage rate of silica fine particles on the surface of toner particles.

[0104] <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.

[0105] <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 the brightness threshold (85 to 128 (256 levels, reference value)) 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.

[0106] <Confirmation of the presence of release agent on the surface of toner particles> The presence of the release agent on the surface of the toner particles is confirmed by the following method.

[0107] (Separation of release agent components from toner) The materials can be separated from the toner by utilizing their differences in solubility in a solvent. First separation: The toner is dissolved in MEK (methyl ethyl ketone) at 23°C, and the soluble matter (amorphous binder resin) is separated from the insoluble matter (releasing agent, colorant, inorganic fine particles, etc.). Second separation: The insoluble matter (release agent, colorant, inorganic fine particles) obtained in the first separation is dissolved in MEK at 100°C, and the soluble matter (release agent) is separated from the insoluble matter (colorant, inorganic fine particles). The solvent used for separation is not particularly limited as long as it is a solvent in which the release agent is insoluble at room temperature.

[0108] (Release agent component analysis) The type of release agent is analyzed by subjecting the release agent components separated from the toner to pyrolysis GC / MS measurement under the following conditions. Measuring device: "Voyager" (product name, manufactured by Thermo Electron) Pyrolysis temperature: 600℃ Column: HP-1 (15 m x 0.25 mm x 0.25 μm) Inlet: 300℃, Split: 20.0 Injection volume: 1.2mL / min Temperature rise: 50℃ (4 min) - 300℃ (20℃ / min)

[0109] (Method for measuring fragment ions of release agents on the surface of toner particles using time-of-flight secondary ion mass spectrometry (TOF-SIMS)) The TOF-SIMS measurement of the release agent on the toner particle surface is carried out using toner particles from which the silica fine particles have been separated by the above-mentioned method for separating the silica fine particles from the toner surface. To measure the fragment ions of the release agent using TOF-SIMS, TRIFT-IV manufactured by ULVAC-PHI, Inc. is used. The analysis conditions are as follows. Sample preparation: Adhering toner particles to an indium sheet Primary ions: Au ions Accelerating voltage: 30 kV Charge neutralization mode: On Measurement mode: Positive Raster: 200 μm Measurement time: 60 seconds When a peak of a fragment ion of the release agent species identified by the above-mentioned release agent component analysis is observed from the obtained mass profile of secondary ion mass / secondary ion charge number (m / z), it is determined that a release agent is present on the surface of the toner particles.

[0110] <Method for calculating the ratio Sw of release agent on the surface of toner particles> The ratio of the release agent present on the surface of the toner particles is calculated by observing, with a scanning electron microscope (SEM), the surface of the toner particles obtained by the above-mentioned operation of separating the silica fine particles and the toner particles. The presence rate of the release agent on the surface of the toner particles can be evaluated as follows. (Method for electronically dyeing toner particles) The toner particles are electronically dyed using the following equipment and conditions. Vacuum electronic staining device: VSC1R1H (Filgen) Staining agent: Ruthenium tetroxide (Filgen) Dyeing atmosphere density: 100Pa Staining time: 5 minutes By staining the surface of the toner particles with ruthenium, a clear contrast can be obtained between the resin portion and the release agent portion on the surface of the toner particles in the backscattered electron image of a scanning electron microscope. This is thought to be because the strength of the ruthenium stain varies depending on the difference in density between the resin portion and the release agent portion, and the difference in the crystallinity of the binder resin and the release agent. As a result, the resin portion and the release agent portion can be distinguished in the backscattered electron image of a scanning electron microscope, which will be described later. A method for obtaining an SEM backscattered electron image of dyed toner particles will be described in detail below.

[0111] (Method for obtaining a backscattered electron image of dyed toner particles) 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: Dyed toner particles are scattered on carbon tape (no Pt deposition is 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.

[0112] (Method for calculating the ratio of release agent present on the surface of toner particles) The release agent content is obtained by analyzing the backscattered electron image of the dyed toner particles 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 the brightness threshold (0 to 153 (256 levels, reference value)) so that only the non-ruthenium-stained areas (exposed release agent areas) in the backscattered electron image 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 particles to be evaluated, and the arithmetic mean value is taken as the presence rate Sw of the release agent on the surface of the toner particles.

[0113] <Measurement of release agent content> The binder resin and the release agent components are separated from the toner particles by the above-mentioned method for separating the release agent components from the toner. The binder resin and the release agent obtained by separation are dried and solidified, and the weights of each are measured to determine the content of the release agent per 100 parts by mass of the toner particles.

[0114] <Method for measuring the number-average particle size of primary particles of silica fine particles> The number-average particle diameter of the silica fine particles is measured by identifying the silica fine particles from a secondary electron image and a backscattered electron image of the same position obtained by observing the toner surface with a scanning electron microscope (SEM).

[0115] (Method for Obtaining Secondary Electron Image and Reflected 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 signals: SE2 (secondary electrons) and EsB (energy-selective backscattered electrons) EsB Grid:700V Magnification: 50,000x Backscattered electron image contrast: 63.0±5.0% (reference value) Backscattered electron image brightness: 38.0±5.0% (reference value) 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 particles is measured, and the arithmetic mean value is taken as the number average particle diameter of the silica particles. Silica particles and strontium titanate particles are distinguished 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 from Type in the Image menu. Next, set the Median diameter to 2.0 pixels from 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, from the Image menu, Select "Threshold" from "Adjust" and particles with a brightness threshold of 105 to 155 (reference value) in the backscattered electrons are silica microparticles, and particles with a brightness threshold of 156 to 255 (reference value) are strontium titanate microparticles.

[0116] <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.

[0117] <Calculation of carbon fixation rate of silica microparticles> (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 (magnetic stirrer, 300 rpm) 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.

[0118] 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 (magnetic stirrer, 300 rpm) for 2 hours. The stirring was then stopped and the mixture was left to stand for 12 hours. The mixture was then centrifuged and all of the supernatant liquid was removed. This process was repeated two more times. The resulting sample was then dried in a thermostatic chamber at 50°C for 2 hours. 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.

[0119] (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

[0120] <Method for measuring the ratio of the content of silica fine particles to the content of strontium titanate fine particles on the surface of toner particles based on elemental strength> The elemental intensity ratio (Si / Sr) of the content of silica fine particles on the surface of the toner particles to the content of strontium titanate fine particles can be measured and calculated by X-ray fluorescence analysis (XRF). The toner is pelletized by press molding as described below to prepare a sample, and the Si atoms contained in the silica particles to be analyzed and the Sr atoms specific to the strontium titanate particles are quantified using a wavelength dispersive X-ray fluorescence analyzer as described below. (i) Examples of equipment used X-ray fluorescence analyzer 3080 (Rigaku Electric Co., Ltd.) (ii) Sample preparation To prepare the sample, a sample press molding machine, MAEKAWA Testing Machine (manufactured by MFG Co., Ltd.), is used. 0.5 g of toner is placed in an aluminum ring (model number: 3481E1), and the load is set to 5.0 tons, and the toner is pressed for 1 minute to form pellets. (iii) Measurement conditions Measuring diameter: 10φ Measurement potential, voltage 50kV, 50~70mA 2θ angle 25.12° Crystal plate LiF Measurement time: 60 seconds (iv) Calculation of the Si element intensity ratio corresponding to the Si atoms contained in the silica particles To calculate the proportion of the Si element intensity of the toner to be analyzed that corresponds to the Si atoms contained in the silica particles, the same measurement is carried out on toner particles from which the silica particles on the toner surface have been separated using the method described above.The Si element intensity corresponding to the Si atoms contained in the silica particles can be calculated using the following formula from the Si element intensity before and after silica separation obtained by the measurement. (Si element intensity ratio corresponding to Si atoms contained in silica microparticles) = (Si element intensity before silica separation - Si element intensity after silica separation) / (Si element intensity before silica separation) (v) Calculation method of Si / Sr Si / Sr = (Si element intensity before silica separation × Si element intensity corresponding to Si atoms contained in silica microparticles / Sr element intensity before silica separation)

[0121] <Method for measuring weight average particle size (D4) of toner> The weight-average particle size (D4) of the toner was measured using a precision particle size distribution measuring device, the Coulter Counter Multisizer, equipped with a 100 μm aperture tube and the electrical resistance method. Using a Beckman Coulter Multisizer 3 (registered trademark, manufactured by Beckman Coulter) and the accompanying dedicated software "Beckman Coulter Multisizer 3 Version 3.51" (manufactured by Beckman Coulter) for setting measurement conditions and analyzing measurement data, measurements are taken with an effective number of measurement channels of 25,000, and the measurement data is analyzed and calculated. The 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 carrying out the 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.

[0122] 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 the electrolyte solution in the beaker in (4) is being irradiated with ultrasonic waves, approximately 10 mg of toner is added little by little to the electrolyte solution and dispersed. The ultrasonic dispersion process is then continued for another 60 seconds. During the ultrasonic dispersion, the water temperature in the water tank is appropriately adjusted to be between 10°C and 40°C. (6) Using a pipette, the electrolytic solution (5) containing the dispersed toner is dropped into the round-bottom beaker (1) placed in the sample stand, and the measurement concentration is adjusted to approximately 5%. Then, measurements are continued until the number of particles measured reaches 50,000. (7) The measurement data is analyzed using the dedicated software provided with the device, and the weight-average particle size (D4) is calculated. 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). [Example]

[0123] Hereinafter, the present disclosure will be described in more detail with reference to Production Examples and Examples, but these are not intended to limit the present disclosure in any way. Note that the numbers of parts in the following formulations all refer to parts by mass.

[0124] <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 silica raw material was charged at a mass ratio of 10:1 and heated to 330°C while being fluidized by stirring. The reactor was then purged with nitrogen gas and sealed, and octamethylcyclotetrasiloxane was sprayed and mixed as a first surface treatment agent using a spray nozzle so that the partial pressure inside the reactor was 200 kPa per 100 parts of the silica raw material. Heating and stirring were then continued for 1 hour to perform 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 1-1.

[0125] <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, the number of parts of the second surface treatment agent, and the treatment temperatures of the first surface treatment agent and 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.

[0126] <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 as large-diameter inorganic fine particles (number-average particle size of primary particles: 55 nm, BET specific surface area: 40 m 2Silica microparticles 7 were obtained in the same manner as in the production example of silica microparticles 1, except that silica microparticles 7 (1:6) were added in a mass ratio of 1:6. The physical properties of silica microparticles 7 are shown in Table 1-2.

[0127] <Production example of silica fine particles 8> The inorganic fine particles were untreated dry silica (primary particle number average particle size 5 nm, BET specific surface area 300 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.

[0128] <Production examples of silica particles 9 and 10> The inorganic fine particles were untreated dry silica (primary particle number average particle size 6 nm, BET specific surface area 300 m 2 Silica microparticles 9 and 10 were obtained by carrying out the same treatment operation as in Production Example of Silica Microparticles 1, except that only silica microparticles (1 / g) were added, both-end carbinol-modified silicone oil (KF-6002 manufactured by Shin-Etsu Chemical Co., Ltd.) was used as the second surface treatment agent, and the number of treatments was as shown in Table 1. The physical properties of Silica Microparticles 9 and 10 are shown in Table 1-2.

[0129] <Production example of silica fine particles 11> The inorganic fine particles were untreated dry silica (primary particle number average particle size 25 nm, BET specific surface area 150 m 2 / 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 as a first surface treatment agent was sprayed and mixed using a spray nozzle until the gauge pressure reached 100 kPa. Thereafter, heating and stirring were continued for 1 hour to carry out a reaction, thereby carrying out a coating treatment. After the treatment, the reaction system was replaced with a nitrogen atmosphere and heated again to 290°C. Subsequently, 15 parts of dimethyl silicone oil (KF-96-50CS manufactured by Shin-Etsu Chemical Co., Ltd.) was sprayed onto 100 parts of the untreated dry silica as a second surface treatment agent, and coating treatment was carried out in the same manner for another hour to obtain silica microparticles 11. The physical properties of silica microparticles 11 are shown in Table 1-2.

[0130] <Production example of silica fine particles 12> The inorganic fine particles were untreated dry silica (primary particle number average particle size 25 nm, BET specific surface area 150 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. After that, heating and stirring were continued for 1 hour to carry out a reaction, thereby carrying out a coating treatment and obtaining silica microparticles 12. The physical properties of silica microparticles 12 are shown in Table 1-2.

[0131] <Production example of silica fine particles 13> The inorganic fine particles were untreated dry silica (primary particle number average particle size 25 nm, BET specific surface area 150 m 2 / g) was added and heated to 250°C while being fluidized by stirring. The inside of the reactor was replaced with nitrogen gas, the reactor was sealed, and while stirring and keeping the temperature continued to maintain the silica in a fluidized state, 30 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 carried out for 1 hour to obtain silica microparticles 13. The physical properties of silica microparticles 13 are shown in Table 1-2.

[0132] <Production example of silica fine particles 14> Silica microparticles 14 were obtained in the same manner as in the production example of silica microparticles 13, except that the number of parts of dimethyl silicone oil was changed as shown in Table 1-1. The physical properties of silica microparticles 14 are shown in Table 1-2.

[0133] <Production example of silica fine particles 15> The inorganic fine particles were untreated dry silica (primary particle number average particle size 30 nm, BET specific surface area 110 m 220 parts of a modified polydimethylsiloxane having hydroxyl groups at its ends was added to the reactor, which was then stirred and heated to 300°C while being fluidized. The atmosphere inside the reactor was replaced with nitrogen gas, and the reactor was sealed. Stirring and heat retention were continued to maintain the silica in a fluidized state, and 20 parts of a modified polydimethylsiloxane having hydroxyl groups at its ends was added to the reactor with hexane. A solution diluted with 100 parts of San was added, and the mixture was treated for 2 hours with continuous stirring to obtain silica fine particles 15. The physical properties of silica fine particles 15 are shown in Table 1-2.

[0134] <Manufacturing example of silica fine particles 16> The inorganic fine particles were untreated dry silica (primary particle number average particle size 25 nm, BET specific surface area 150 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 and perform a coating treatment. After the treatment, the reaction system was replaced with a nitrogen atmosphere and heated again to 250°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 16. The physical properties of silica microparticles 16 are shown in Table 1-2.

[0135] <Production example of silica fine particles 17> The inorganic fine particles were untreated dry silica (primary particle number average particle size 25 nm, BET specific surface area 150 m 2 / g) was added and heated to 250°C while being fluidized by stirring. The atmosphere inside the reactor was replaced with nitrogen gas, the reactor was sealed, and 25 parts of hexamethyldisilazane was sprayed as a first surface treatment agent per 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 17. The physical properties of silica microparticles 17 are shown in Table 1-2.

[0136] <Magnetic body 1 manufacturing example> An aqueous solution containing ferrous hydroxide was prepared by mixing 1.05 equivalents of caustic soda solution relative to elemental iron, P2O5 in an amount equivalent to 0.15 mass% of phosphorus relative to elemental iron, and SiO2 in an amount equivalent to 1.50 mass% of silicon relative to elemental iron into an aqueous solution of ferrous sulfate. The pH of the aqueous solution was adjusted to 8.0, and an oxidation reaction was carried out at 85°C while blowing in air to prepare a slurry containing seed crystals. Next, an aqueous solution of ferrous sulfate was added to this slurry in an amount equivalent to 1.05 relative to the initial alkali content (sodium content of caustic soda), and the pH of the slurry was maintained at 7.6. Air was blown in to carry out an oxidation reaction, yielding a slurry containing magnetic iron oxide particles. The resulting magnetic iron oxide particles were filtered using a filter press, washed with a large amount of water, and then dried at 120°C for 2 hours. The resulting particles were then crushed to yield Magnetic Material 1, with a number-average particle size of 150 nm.

[0137] <Production Example of Toner Particle 1> Binder resin 100.0 parts (Amorphous PES resin. Amorphous polyester resin obtained by the condensation reaction of ethylene oxide and propylene oxide adducts of bisphenol A with terephthalic acid; Mw=9500, Tg=58°C) ·Magnetic material 1 95.0 parts Release agent: Fischer-Tropsch wax 5.5 parts (C105, manufactured by Sasol, melting point 105°C) Monoazo dye iron complex (T-77, manufactured by Hodogaya Chemical Co., Ltd.) 2.0 parts The above raw materials were premixed in a Henschel mixer FM10C (Mitsui Miike Chemical Engineering Co., Ltd.). Then, the kneading was performed using a twin-screw kneading extruder (PCM-30, manufactured by Ikegai Iron Works Co., Ltd.) set at a rotation speed of 250 rpm, with the set temperature adjusted so that the direct temperature near the outlet of the kneaded material was 145°C. The obtained molten kneaded material was cooled, and the cooled molten kneaded material was coarsely pulverized using a cutter mill. Then, the obtained coarsely pulverized material was crushed using a Turbo Mill T-250 (manufactured by Turbo Kogyo Co., Ltd.). The feed rate was set to 25 kg / hr, and the air temperature was adjusted so that the exhaust temperature was 38°C. The mixture was adjusted, finely pulverized, and classified using a multi-division classifier utilizing the Coanda effect. As a result, toner particles 1 with a weight average particle size (D4) of 7.6 μm were obtained. The physical properties of toner particles 1 are shown in Table 2.

[0138] <Production Examples of Toner Particles 2 to 6> Toner particles 2 to 6 were obtained by carrying out the same operations as in the method for producing toner particles 1, except that the amount of release agent was changed to the conditions shown in Table 2. The physical property values ​​of toner particles 2 to 6 are shown in Table 2.

[0139] <Production Examples of Toner Particles 7 to 9> Toner particles 7 to 9 were obtained by carrying out the same operations as in the method for producing toner particles 1, except that the type of release agent was changed to carnauba wax (manufactured by Nippon Seiro Co., Ltd., melting point 83°C) and the amount of release agent was changed to the conditions shown in Table 2. The physical property values ​​of toner particles 7 to 9 are shown in Table 2.

[0140] <Production Example of Toner Particles 10> Except for changing the binder resin type to a styrene / n-butyl acrylate copolymer (styrene acrylic resin with a mass ratio of styrene and n-butyl acrylate of 78:22; Mw = 8500, Tg = 58°C), the same operations as in the production method for toner particles 9 were carried out to obtain toner particles 10 having a weight average particle size (D4) of 7.5 μm. The physical properties of toner particles 10 are shown in Table 2.

[0141] <Production Example of Toner Particle 11> Except for changing the binder resin type to a styrene / n-butyl acrylate copolymer (styrene-acrylic resin with a mass ratio of styrene and n-butyl acrylate of 78:22; Mw=8500, Tg=58°C), the same processing operations as in the production method for toner particles 3 were carried out to obtain toner particles 11 having a weight average particle size (D4) of 7.5 μm. The physical properties of toner particles 11 are shown in Table 2.

[0142] <Production Example of Toner Particles 12> Toner particles 12 were prepared by emulsion aggregation according to the following procedure. (Production of binder resin particle dispersion 1) 89.5 parts of styrene, 9.2 parts of butyl acrylate, 1.3 parts of acrylic acid, and 3.2 parts of n-lauryl mercaptan were mixed and dissolved, and an aqueous solution prepared by mixing 1.5 parts of Neogen RK (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) in 150 parts of ion-exchanged water was added to this mixed solution and dispersed. An aqueous solution of 0.3 parts of potassium persulfate mixed with 10 parts of ion-exchanged water was added thereto while stirring slowly for another 10 minutes. After nitrogen substitution, emulsion polymerization was carried out for 6 hours at 70° C. After completion of polymerization, the reaction solution was cooled to room temperature, and ion-exchanged water was added to obtain binder resin particle dispersion 1 having a solid content of 12.5 mass % and a volume-based median diameter of 0.2 μm.

[0143] (Production Example of Release Agent Dispersion 1) 100 parts of a release agent (Fischer-Tropsch, melting point: 105°C) and 15 parts of NEOGEN RK were mixed with 385 parts of ion-exchanged water, and the mixture was dispersed for about 1 hour using a wet jet mill JN100 (manufactured by Joko Co., Ltd.) to obtain a release agent dispersion 1. The solid content concentration of the release agent dispersion 1 was 20% by mass.

[0144] (Production example of magnetic iron oxide dispersion liquid 1) 100 parts of magnetic iron oxide particles and 10.0 parts of NEOGEN SC were mixed with 890 parts of ion-exchanged water, and dispersed for 1 hour using a wet jet mill JN100 to obtain magnetic iron oxide dispersion liquid 1.

[0145] (Production Example of Toner Particle Dispersion 1) 1:265 parts of binder resin particle dispersion, 1:10 parts of release agent dispersion, and 1:65 parts of magnetic iron oxide dispersion were placed in a container and dispersed using a homogenizer (IKA: Ultra Turrax T50). While stirring, the temperature inside the container was adjusted to 30°C, and 1 mol / L hydrochloric acid was added to adjust the pH to 5.0. After leaving it for 3 minutes, the temperature was raised to 50°C to generate agglomerated particles. In this state, the particle size of the agglomerated particles was measured using a Coulter Counter Multisizer 3 (registered trademark, manufactured by Beckman Coulter, Inc.). When the weight-average particle size of the agglomerated particles reached 6.2 μm, 1 mol / L aqueous sodium hydroxide solution was added to adjust the pH to 8.0 and stop particle growth. Thereafter, the temperature was raised to 95° C. to fuse and spheronize the aggregated particles. When the average circularity reached 0.980, the temperature was lowered to 30° C., and toner particle dispersion 1 was obtained.

[0146] Hydrochloric acid was added to the obtained toner particle dispersion liquid 1 to adjust the pH to 1.5 or less, and the mixture was then left to stand with stirring for 1 hour, followed by 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 using a flash jet dryer (manufactured by Seishin Enterprises). The drying conditions were an inlet temperature of 90°C and an outlet temperature of 40°C. The toner cake supply speed was adjusted according to the moisture content of the toner cake so that the outlet temperature did not deviate from 40°C. Furthermore, a multi-division classifier utilizing the Coanda effect was used to remove fine and coarse particles, yielding toner particles 12. The weight-average particle size (D4) of toner particles 12 was 8.4 μm, and the glass transition temperature (Tg) was 57°C. The physical properties of toner particles 12 are shown in Table 2.

[0147] <Toner 1 manufacturing example> Using an FM mixer ("FM-10B" manufactured by Nippon Coke & Engineering Co., Ltd.), 1:100 parts of toner particles, 1:1.4 parts of silica microparticles, and 0.2 parts of strontium titanate microparticles (number average particle size 1.2 μm) were mixed at a rotation speed of 3500 rpm for 180 seconds to obtain a toner mixture. Thereafter, coarse particles were removed using a 300 mesh (opening 48 μm) sieve to obtain Toner 1. Table 3 shows the production conditions and physical properties.

[0148] <Production examples of toners 2 to 31> Toners 2 to 32 were produced in the same manner as in the production example of Toner 1, except that the types of toner particles and silica fine particles, the number of parts of silica fine particles added, the number of parts of strontium titanate fine particles added, and external addition conditions in Toner 1 were changed as shown in Table 3. The production conditions and physical properties are shown in Table 3.

[0149] Example 1 The obtained toner 1 was subjected to the following evaluations. (test) To evaluate fixation performance at high speeds, an HP LaserJet Enterprise M609dn was modified to a process speed of 500 mm / sec. It was also modified to allow connection to an external power source to change the transfer bias, and evaluations were conducted on charge amount, charge stability, fogging, and trailing edge offset. The evaluation results are shown in Table 4.

[0150] (1) Evaluation of charge amount and charge stability After leaving the above image output tester and the toner cartridge filled with the evaluation toner in a high temperature and humidity environment of 32.5°C / 80%RH for more than one day, the image output tester was used to test the image quality of a 4-dot horizontal line. A test was conducted in which 20,000 sheets of a horizontal line pattern with the above printed every 176 dots were printed. After the initial 10 sheets and 20,000 sheets of paper had been passed through in the above test, the charge amount (μC / g) of the toner on the developing carrier in the toner cartridge was measured using a blow-off powder charge amount measuring device TB-200 (manufactured by Toshiba Chemical Co., Ltd.), and the chargeability and charge stability in a high-temperature, high-humidity environment were evaluated. The larger the chargeability value, the higher the chargeability, and the smaller the difference in charge amount between the initial state and after 20,000 sheets have been fed, the better the charge stability of the toner. The evaluation ranks for charge amount and charge stability were determined and evaluated as follows: [Evaluation criteria] (charge amount) A: Charge amount less than -30.0 μC / g B: Charge amount is -30.0 μC / g or more and less than -27.5 μC / g C: Charge amount is -27.5μC / g or more and less than -25.0μC / g D: Charge amount is -25.0 μC / g or more and less than -22.5 μC / g E: Charge amount is -22.5μC / g or more (Charging stability) The difference in charge amount between the initial stage and after 20,000 sheets is A: Less than -2.0 μC / g B: -2.0μC / g or more and less than -4.0μC / g C: -4.0μC / g or more and less than -6.0μC / g D: -6.0μC / g or more and less than -8.0μC / g E: -8.0μC / g or more

[0151] (2) Fog evaluation Fog was evaluated by comparing the whiteness of the transfer paper measured using a reflection densitometer (Reflectometer Model TC-6DS, manufactured by Tokyo Denshoku Co., Ltd.) with the whiteness of a solid white image after a 20,000-sheet print test in a high-temperature, high-humidity environment of 32.5°C / 80%RH. A lower value indicates better fog suppression. A: Fog density is less than 1.0% B: Fog density is 1.0% or more and less than 2.0% C: Fog density is 2.0% or more and less than 3.0% D: Fog density is 3.0% or more

[0152] (3) Evaluation of rear end offset Using the image output tester described above, the settings of the fixing unit were further changed to lower the temperature by 10°C. In a high-temperature, high-humidity environment (32.5°C / 80%RH), the fixing unit was removed between evaluations and thoroughly cooled using a fan or similar device before the following evaluations were carried out. By thoroughly cooling the fixing unit after evaluation, the temperature of the fixing nip, which had risen after image output, was cooled, making it possible to evaluate the toner fixability more strictly and with better reproducibility. When evaluating the trailing edge offset, Canon A4 size OceRedLabel paper (basis weight 80 g / m 2 ) that had been left in a high-temperature, high-humidity environment for 48 hours or more was used. By using relatively heavy paper with a large surface roughness and paper that had been left in a high-temperature, high-humidity environment (left-standing paper), it was possible to strictly evaluate trailing edge offset. In this evaluation, a solid black image was printed on the paper after the fixing unit had cooled down sufficiently. At this time, the toner amount on the paper was 9 g / m. 2 It was adjusted so that The evaluation criteria for the trailing edge offset were as follows: the offset level was visually evaluated for a solid black image output in the above-described procedure. A: There is no offset at all B: If you look closely, you can see a slight offset C: Offset is visible but not noticeable D: Offset is noticeable

[0153] <Examples 2 to 23> Evaluation was carried out in the same manner as in Example 1 except that toners 2 to 23 were used.

[0154] <Comparative Examples 1 to 8> Evaluation was carried out in the same manner as in Example 1 except that toners 24 to 31 were used.

[0155] [Table 1-1] In Table 1-1, for silica particles 1 to 6, the substrate BET / m 2 / g column indicates the BET specific surface area of ​​200 m 2 / g small silica particles and 50m 2 This indicates that large-sized silica particles of 10:1 / g were used in a mass ratio of small-sized silica to large-sized silica (Silica particle 7 has a BET specific surface area of ​​200 m). 2 / g small particle size silica: 40m 2 / g large particle silica = 1:6). D4 indicates octamethylcyclotetrasiloxane. Regarding the quantity, HMDS (hexamethyldisilazane) indicates the number of parts. [Table 1-2] In Table 1-2, B is the specific surface area of ​​the silica particles (m 2 / g), and before washing, D / S / B is the solid of silica fine particles. 29 indicates the ratio (D / S) / B in the Si-NMR DD / MAS analysis, D / S / B after washing indicates the ratio (D / S) / B after washing the silica microparticles with chloroform, Sn indicates {(ab) × c × NA} / (d × e), C content indicates the carbon content, and number average particle size indicates the number average particle size of the primary particles of the silica microparticles. For example, the value "1.5E-03" is "1.5 x 10 -3 " indicates that

[0156] [Table 2] In the table, PES indicates polyester resin, StAc indicates styrene acrylic resin, *1 indicates the presence or absence of a release agent on the surface of the toner particle, and Sw indicates the presence rate (area %) of the release agent on the surface of the toner particle.

[0157] [Table 3] In the table, Ssi indicates the coverage rate of silica fine particles on the surface of a toner particle, Sw indicates the presence rate of release agent on the surface of a toner particle, *2 indicates the presence or absence of fragment ions of formula (1), and Si / Sr indicates the ratio of the content of silica fine particles to the content of strontium titanate fine particles in the toner, based on elemental strength, as determined by fluorescent X-ray analysis.

[0158] [Table 4]

[0159] The present disclosure relates to the following configurations. (Configuration 1) A toner containing toner particles containing a binder resin and a release agent, 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, 2.00 g of the silica fine particles were dispersed in a mixed solution of 25.0 g of ethanol and 75.0 g of a 20% by mass aqueous solution of NaCl, and titration with sodium hydroxide was carried out. Sn defined as Sn={(ab)×c×NA} / (d×e) satisfies the following formula (2): 0.05≦Sn≦0.20 (2) In the formula (2), a is the titer (L) of NaOH required to adjust the pH of the mixture in which the silica fine particles are dispersed to 9.0, b is the titer (L) of NaOH required to adjust a 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 ​​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; The release agent is present on the surface of the toner particles. A toner characterized by: (Configuration 2) When the presence rate of the release agent on the surface of the toner particle is Sw (area %), 2. The toner according to claim 1, wherein Sw is 10 to 70 area %. (Configuration 3) 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 configuration 1 or 2, wherein the Ssi is 25 to 90 area %. (Configuration 4) The presence rate of the release agent on the surface of the toner particle is defined as Sw (area %), When the coverage rate of the silica fine particles on the surface of the toner particles calculated from an image of the toner surface observed by a scanning electron microscope is defined as Ssi (area %), 4. The toner according to any one of configurations 1 to 3, wherein the ratio of Sw to Ssi (Sw / Ssi) is 0.18 to 2.80. (Configuration 5) 5. The toner according to any one of configurations 1 to 4, wherein the carbon fixation rate when the silica fine particles are washed with chloroform is 30 to 70%. (Configuration 6) 6. The toner according to any one of configurations 1 to 5, wherein the content of the silica fine particles is 0.2 to 2.2 parts by mass with respect to 100 parts by mass of the toner particles. (Configuration 7) 7. The toner according to any one of configurations 1 to 6, wherein the number average particle size of the primary particles of the silica fine particles is 5 to 50 nm. (Configuration 8) 8. The toner according to any one of configurations 1 to 7, wherein the silica fine particles are surface-treated with at least a compound represented by the following formula (3): [ka] (R in Equation (3) 1 , R 2 are each independently a carbinol group, a hydroxyl group, an epoxy group, a carboxy group, an alkyl group, or a hydrogen atom, and m is an integer of 1 to 200. (Configuration 9) the toner further contains strontium titanate fine particles on the surface of the toner particles, 9. The toner according to any one of configurations 1 to 8, wherein the ratio (Si / Sr) of the content of the silica fine particles to the content of the strontium titanate fine particles in the toner based on elemental intensity, as determined by fluorescent X-ray analysis, is 0.10 to 1.50. (Configuration 10) 10. The toner according to any one of configurations 1 to 9, wherein the release agent is at least one selected from the group consisting of hydrocarbon waxes and ester waxes. (Configuration 11) 11. The toner according to any one of configurations 1 to 10, wherein the content of the release agent is 0.5 to 15.0 parts by mass with respect to 100 parts by mass of the binder resin. (Configuration 12) 12. The toner according to any one of configurations 1 to 11, wherein the silica fine particles are silica fine particles treated with cyclic siloxane and then treated with silicone oil.

Claims

1. A toner containing toner particles containing a binder resin and a release agent, and silica fine particles on the surfaces of the toner particles, When the presence rate of the release agent on the surface of the toner particle is Sw (area %), The Sw is 10 to 70 area %, In the 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 liquid 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={(a-b)×c×NA} / (d×e) satisfies the following formula (2): 0.05≦Sn≦0.20 ... (2) In the formula (2), a is the titer (L) of NaOH required to adjust the mixed liquid having the silica fine particles dispersed therein to pH 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 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 Chemical shifts 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, the sum of the areas of the peaks of M units, D units, T units, and Q units 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 the (D / S) / B ratio was measured and found to be 1.7×10 －４ ~4.9 x 10 －３ and In the chemical shift, when the area of ​​a peak having a peak top in the range of more than −19 ppm to −17 ppm is defined as D1, the ratio of D1 to D (D1 / D) is 0.10 to 0.30; The release agent is present on the surface of the toner particles. A toner characterized by:

2. When the coverage rate of the surface of the toner particle with the silica fine particles calculated from an image of the toner surface observed by a scanning electron microscope is defined as Ssi (area %), 2. The toner according to claim 1, wherein the Ssi is from 25 to 90 area %.

3. When the coverage rate of the surface of the toner particle by the silica fine particles is Ssi (area %) calculated from an image of the surface of the toner observed by a scanning electron microscope, 3. The toner according to claim 1, wherein a ratio of Sw to Ssi (Sw / Ssi) is from 0.18 to 2.

80.

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

5. 3. The toner according to claim 1, wherein the content of the silica fine particles is 0.2 to 2.2 parts by mass with respect to 100 parts by mass of the toner particles.

6. 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.

7. 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 hydroxyl group, an epoxy group, a carboxy group, an alkyl group, or a hydrogen atom, and m is an integer of 1 to 200.

8. the toner further contains strontium titanate microparticles on the surface of the toner particles, The toner has a ratio (Si / Sr) of the content of the silica fine particles to the content of the strontium titanate fine particles based on elemental strength, as determined by fluorescent X-ray analysis, of 0.10 to 1.

3. The toner according to claim 1, wherein the molecular weight of the toner is 50.

9. 3. The toner according to claim 1, wherein the release agent is at least one selected from the group consisting of a hydrocarbon wax and an ester wax.

10. 3. The toner according to claim 1, wherein the content of the release agent is 0.5 to 15.0 parts by mass with respect to 100 parts by mass of the binder resin.

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

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