toner

Abstract

To provide a toner that, even in use in a low humidity environment, can easily maintain proper electrification characteristics similar to those in normal temperature and normal humidity, and can prevent ghost.SOLUTION: A toner contains a toner particle and silica fine particles. In measurement in time-of-flight secondary ion mass spectroscopy of the silica fine particles, fragment ions corresponding to the D-unit structure are observed. When the silica fine particles are dispersed in a specific mixed solution and a titration operation using NaOH is performed, a titration amount falls within a specific range. In solid 29Si-NMR measurement of the silica fine particles, when the area of a peak from -25 to -15 ppm is defined as D, the total sum of the areas of peaks from -140 to 100 ppm is defined as S, and the area of a peak exceeding -19 ppm and -17 ppm or less is defined as D1, the specific surface area of the silica fine particles, D, D1, and S satisfy a specific relationship. A specific vinyl resin is present on the surface of the toner particle.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] In recent years, there has been a demand for longer lifespans and the ability to produce high-quality images regardless of the environment, in order to accommodate the diverse usage methods of photocopiers and printers. The electrostatic properties of toner have a significant impact on achieving high image quality, and various studies have been conducted on this matter.

[0003] For example, Patent Document 1 explores a method for incorporating acrylic resin into toner particles. Furthermore, with the aim of improving environmental stability, for example, Patent Document 2 describes a method of adding silica particles with a hydrophobic surface treatment to toner particles. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2009-031426 [Patent Document 2] Japanese Patent Publication No. 2008-145490 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] Acrylic resins, such as those used in Patent Document 1, tend to improve the chargeability of toners because their acrylic groups are easily polarized. On the other hand, they tend to become overcharged in low-humidity environments, posing a challenge from the standpoint of environmental stability. Furthermore, while the technology described in Patent Document 2 can achieve certain effects such as reduced hygroscopicity by imparting hydrophobicity to the toner, it is difficult to prevent image quality disturbances such as ghosting caused by overcharging in low-humidity environments. For the reasons stated above, the development of a toner with excellent static charge stability regardless of the environment is desirable. This disclosure relates to a toner that can easily maintain proper electrostatic properties, similar to those at normal temperature and humidity, even when used in low-humidity environments, and can suppress ghosting. [Means for solving the problem]

[0006] This disclosure relates to a toner containing toner particles and silica fine particles on the surface of said toner particles, In time-of-flight secondary ion mass spectrometry measurements of the silica nanoparticles, fragment ions corresponding to the structure shown in equation (1) below were observed. [ka] In equation (1), n ​​represents an integer of 1 or greater, When 2.00 g of the silica fine particles are 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, the Sn, defined as Sn = {(ab) × c × Na} / (d × e), satisfies the following equation (2). 0.05 ≤ Sn ≤ 0.20 ···(2) In formula (2), a is the amount of NaOH titration (L) required to adjust the mixture containing the dispersed silica particles to pH 9.0. b is the amount of NaOH titration (L) required to adjust a mixture of 25.0 g of ethanol and 75.0 g of 20% by mass NaCl aqueous solution to pH 9.0. c is the concentration (mol / L) of the NaOH solution used in the titration. NA is Avogadro's number, d is the mass (g) of the silica fine particles, e is the BET specific surface area (nm) of the silica nanoparticles. 2 / g) is Solid silica fine particles 29 In the chemical shift obtained by the Si-NMR DD / MAS method, D is the area of ​​the peaks with peak tops in the range of -25 to -15 ppm, S is the sum of the areas of the M, D, T, and Q unit peaks in the range of -140 to 100 ppm, and B is the specific surface area of ​​the silica nanoparticles.2 When we set it to / g, The ratio of (D / S) to B, (D / S) / B, is 5.7 × 10 -4 ~56×10 -4 And, The (D / S) / B value measured after washing the silica microparticles with chloroform was 1.7 × 10⁻⁶. -4 ~56×10 -4 And, In the chemical shift, when D1 is defined as the area of ​​the peaks where the peak top is located in the range between -19 ppm and -17 ppm, The ratio of D1 to D (D1 / D) is between 0.10 and 0.30. This relates to a toner in which a vinyl resin having the structure shown in the following formula (9) is present on the surface of the toner particles. [ka] (In formula (9), R 4 (This refers to a hydrocarbon group having 1 to 10 carbon atoms.) [Effects of the Invention]

[0007] This disclosure makes it possible to provide a toner that can easily maintain the same appropriate electrostatic properties as at normal temperature and humidity even when used in low-humidity environments, and that can suppress ghosting. [Brief explanation of the drawing]

[0008] [Figure 1] Schematic diagram of the Ghost evaluation image [Modes for carrying out the invention]

[0009] In this disclosure, descriptions of numerical ranges such as "XX or more and YY or less" or "XX to YY" mean a numerical range that includes the lower and upper limits, unless otherwise specified. When numerical ranges are described in steps, the upper and lower limits of each numerical range can be combined in any way. Furthermore, a monomer unit refers to the reacted form of monomer material in a polymer.

[0010] The inventors have found that the above problem can be solved by combining toner particles having a specific acrylic group with silica nanoparticles that have an appropriate amount of D1 structure by effectively arranging dimethylsiloxane chains and further controlling the amount of silanol groups.

[0011] In electrophotography, toner is required to have excellent properties such as fluidity and electrostatic chargeability. In particular, when focusing on image quality, high electrostatic chargeability is necessary to faithfully reproduce the image on the electrostatic latent image carrier. Having this capability is crucial. However, electrostatic properties are easily affected by the environment, and moisture in the air, in particular, often reduces the toner's charge. Printers are used in air-conditioned, relatively low-humidity environments, as well as in normal temperature and humidity environments, and even high-humidity environments, so the problem is that image quality can vary depending on the environment.

[0012] The inventors focused on a particular image quality issue: ghosting, where the history of the upper part of an image remains in the lower part of the image. Ghosting is a phenomenon that occurs when the charge of the toner carried on the toner carrier is too high or too low after the toner has transferred to the electrostatic latent image carrier. Conventionally, various studies have been conducted to improve electrostatic properties. According to the inventors' research, when acrylic groups are placed on the surface of toner particles, the acrylic groups become polarized, resulting in excellent electrostatic properties. However, the acrylic groups absorb moisture, leading to a decrease in electrostatic properties in high-humidity environments.

[0013] We found that by combining the toner particles having the aforementioned acrylic groups with silica nanoparticles having D units and D1 units on their surface and a controlled amount of silanol groups, the difference in electrostatic charge between normal temperature and humidity and high temperature and low humidity environments can be reduced.

[0014] This disclosure relates to a toner containing toner particles and silica fine particles on the surface of said toner particles, In time-of-flight secondary ion mass spectrometry measurements of the silica nanoparticles, fragment ions corresponding to the structure shown in equation (1) below were observed. [Chemical formula] In the formula (1), n represents an integer of 1 or more. When 2.00 g of the silica fine particles are dispersed in a mixed solution of 25.0 g of ethanol and 75.0 g of a 20% by mass NaCl aqueous solution and a titration operation is performed using 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 titration amount (L) of NaOH required to adjust the pH of the mixed solution in which the silica fine particles are dispersed to pH 9.0. b is the titration amount (L) of NaOH required to adjust the pH of a mixed solution of 25.0 g of ethanol and 75.0 g of a 20% by mass NaCl aqueous solution to pH 9.0. c is the concentration (mol / L) of the NaOH solution used for 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) of the silica fine particles. Regarding the solid of the silica fine particles 29 In the chemical shift obtained by the Si-NMR DD / MAS method, when the area of the peak with the peak top in the range of -25 to -15 ppm is D, and the total area of the peaks of the M unit, D unit, T unit, and Q unit existing in the range of -140 to -100 ppm is S, and the specific surface area of the silica fine particles is B (m 2 / g), The value of the ratio of (D / S) to B, (D / S) / B, is 5.7 × 10 -4 ~56 × 10 -4 and The (D / S) / B measured after washing the silica fine particles with chloroform is 1.7 × 10 -4 ~56 × 10 -4 and In the chemical shift, when the area of the peak with the peak top in the range exceeding -19 ppm and not exceeding -17 ppm is D1, The ratio of D1 to D (D1 / D) is between 0.10 and 0.30. This relates to a toner in which a vinyl resin having the structure shown in the following formula (9) is present on the surface of the toner particles. [ka] (In formula (9), R 4 (This refers to a hydrocarbon group having 1 to 10 carbon atoms.)

[0015] The effects obtained by the above-mentioned combination of specific silica microparticles and toner particles are described below. The surface treatment of the silica microparticles can be confirmed by time-of-flight secondary ion mass spectrometry (TOF-SIMS). In time-of-flight secondary ion mass spectrometry (TOF-SIMS) measurements of silica nanoparticles, it is necessary to observe fragment ions corresponding to the structure shown in equation (1). The observation of fragment ions shown in equation (1) indicates that the silica nanoparticles have been surface-treated with a surface treatment agent having a dimethylsiloxane structure. [ka]

[0016] (In formula (1), n ​​is an integer of 1 or greater (preferably between 1 and 500, more preferably between 1 and 200, even more preferably between 1 and 100, and even more preferably between 1 and 80).) TOF-SIMS is a method for analyzing the surface composition of a sample by irradiating the sample with ions and analyzing the mass of secondary ions emitted from the sample. Since secondary ions are emitted from a region several nanometers deep from the sample surface, it is possible to analyze the structure near the surface of silica nanoparticles. The mass spectrum of secondary ions obtained by the measurement is a fragment ion that reflects the molecular structure of the surface treatment agent of the silica nanoparticles.

[0017] In TOF-SIMS measurements, fragment ions corresponding to the structure shown in formula (1) are observed in silica nanoparticles. In this disclosure, structural units having this structure are defined as D units. When D unit fragment ions are observed by TOF-SIMS, it means that the silica nanoparticles have been surface-treated with a surface treatment agent containing D units.

[0018] Next, it is necessary to control the amount of Si-OH groups in the silica nanoparticles. When the silica nanoparticles are dispersed in a solvent and titrated with sodium hydroxide, it is necessary to satisfy the following equation (2). This titration operation aims to neutralize the acid groups (Si-OH groups) present on the surface of the silica nanoparticles. The amount of Si-OH groups is the value Sn(groups / nm) which can be determined from the titration volume of sodium hydroxide. 2 This can be evaluated by the following: This is because the Si-OH groups in the silica nanoparticle substrate and the Si-OH groups derived from the surface treatment agent undergo a neutralization reaction with sodium hydroxide. The surface of silica microparticles contains silanol groups (Si-OH groups) present on the surface of the silica microparticle substrate, OH groups at the ends of the dimethylsiloxane chain, and acidic groups derived from surface treatment agents. These acidic groups readily interact with moisture in the air and are easily polarized, and when present on the surface of toner particles, they tend to exhibit excellent charge imparting properties.

[0019] According to the inventors' research, it was found that if the values ​​in equation (2) are satisfied, excellent charge imparting properties can be obtained while minimizing the effect of moisture. If the values ​​are below the lower limit of equation (2), the charge imparting properties are insufficient, and the chargeability of the toner decreases. On the other hand, if the upper limit of equation (2) is exceeded, there will be an excess of Si-OH groups on the surface of the silica nanoparticles. For example, in a high-humidity environment, the ability of the silica nanoparticles to impart charge decreases due to the influence of moisture, while conversely, in a normal temperature and humidity environment, the ability of the silica nanoparticles to impart charge is high. Also, in a low-humidity environment, they are more susceptible to the influence of moisture and tend to become overcharged. As a result, there is a large difference in the amount of charge of the toner depending on the environment, causing fluctuations in developability and making ghosting more likely.

[0020] Specifically, when 2.00 g of silica fine particles were dispersed in a mixture of 25.0 g of ethanol and 75.0 g of a 20% by mass NaCl aqueous solution and titrated using sodium hydroxide, The Sn defined as Sn = {(ab) × c × NA} / (d × e) must satisfy equation (2) below. 0.05 ≤ Sn ≤ 0.20 ···(2) In formula (2), a is the amount of NaOH titration (L) required to adjust the above mixture containing dispersed silica nanoparticles to pH 9.0. b is the amount of NaOH titration (L) required to adjust a mixture of 25.0 g of ethanol and 75.0 g of 20% by mass NaCl aqueous solution to pH 9.0. c is the concentration (mol / L) of the NaOH solution used in the titration. NA is Avogadro's number, d is the mass (g) of the silica nanoparticles. e is the BET specific surface area (nm) of the silica nanoparticles. 2 It is / g).

[0021] Sn is obtained by the titration procedure described above. Since silanol groups on the surface of silica nanoparticles are immediately neutralized by sodium hydroxide, we believe that Sn correlates with the number of silanol groups per unit surface area of ​​the silica nanoparticle surface. When Sn satisfies equation (2), the amount of silanol groups on the surface of the silica nanoparticle substrate and the amount of silanol groups in the structure derived from the surface treatment agent of the silica nanoparticles become appropriate, improving the charge retention regardless of the environment. Sn is preferably 0.05 to 0.18, and more preferably 0.10 to 0.15.

[0022] The amount of Sn can be increased by treating the silica nanoparticle substrate under conditions where the reaction of the surface treatment agent does not proceed, so that Si-OH groups remain on the surface of the silica nanoparticle substrate, or by adding only a small amount of the treatment agent so as not to completely cover the surface of the silica nanoparticle substrate. On the other hand, the amount of Sn can be decreased by reducing the silanol groups on the surface of the silica nanoparticles through surface treatment, or by treating with a surface treatment agent that does not contain silanol groups. In addition, extending the reaction time or raising the temperature during surface treatment is also effective.

[0023] As mentioned above, the above problems can be solved by combining silica with a specific structure on its surface and toner particles with a specific resin on its surface. Therefore, it is necessary to control the surface treatment state ((D / S) / B, D1 / D) of the silica nanoparticles. The surface treatment state of the silica nanoparticles is solid 29 The result is calculated using the Si-NMR DD / MAS method. In the DD / MAS measurement method, all Si atoms in the sample are observed, providing quantitative information about the chemical bonding state of Si atoms in silica nanoparticles.

[0024] Generally, solid 29 Si-NMR allows observation of four types of peaks for Si atoms in a solid sample: M-unit (Equation (4)), D-unit (Equation (5)), T-unit (Equation (6)), and Q-unit (Equation (7)). M unit: (R i )(R j )(R k )SiO 1 / 2 Formula (4) D unit: (R g )(R h )Si(O 1 / 2 )2 formula (5) T unit: R m si(O 1 / 2 )3 formula (6) Q unit: Si(O) 1 / 2 )4 formula (7) R in equations (4), (5), and (6) i , R j , R k , R g , R h, R m This refers to alkyl groups such as hydrocarbon groups having 1 to 6 carbon atoms, halogen atoms, hydroxyl groups, acetoxy groups, or alkoxy groups that are bonded to silicon.

[0025] When silica nanoparticles are measured using DD / MAS, the Q unit indicates a peak corresponding to the Si atoms in the silica nanoparticle substrate before surface treatment. In this disclosure, when silica nanoparticles are surface-treated with a surface treatment agent such as silicone oil, the portion derived from the surface treatment agent is also referred to as silica nanoparticles. Furthermore, silica nanoparticles before surface treatment are also referred to as the silica nanoparticle substrate. The BET specific surface area of ​​the silica nanoparticles after surface treatment is given by B(m²). 2 Let it be / g). The M, D, and T units represent peaks corresponding to the structure of the surface treatment agent for silica fine particles, as shown in formulas (4) to (6) above. All are solids 29 Identification is possible by the chemical shift values ​​of the Si-NMR spectrum. Q units appear in the chemical shift range of -130 to -85 ppm, T units in the range of -65 to -51 ppm, D units in the range of -25 to -15 ppm, and M units in the range of 10 to 25 ppm, and each can be quantified by its integral value. The respective peak integral values ​​are denoted as Q, T, D, and M, and the sum of these integral values ​​is denoted as S.

[0026] Solid silica nanoparticles 29 In the chemical shift obtained by the Si-NMR DD / MAS method, D is the area of ​​the peaks with peak tops in the range of -25 to -15 ppm, and S is the sum of the areas of the M, D, T, and Q units of the peaks in the range of -140 to 100 ppm. Then, B (m²) is the specific surface area of ​​the silica nanoparticles. 2 Let (D / S) be (g). In this case, the ratio of (D / S) to B is (D / S) / B (hereinafter also called DSB), which is 5.7 × 10 -4 ~56×10 -4 That is the case. Furthermore, the (D / S) / B (hereinafter also referred to as DSB-W) measured after washing silica microparticles with chloroform was 1.7 × 10⁻⁶. -4 ~56×10 -4 That is the case. DSB represents the amount of Si atoms per unit surface area that constitutes the D unit relative to the total Si atomic amount of silica nanoparticles. Here, in TOF-SIMS, the fragment shown in equation (1) above is observed, and the solid 29 In Si-NMR measurements, silica nanoparticles exhibiting peaks in the D unit indicate that they have been surface-treated with a compound containing a dimethylsiloxane structure.

[0027] In other words, DSB represents the amount of dimethylsiloxane on the surface of silica nanoparticles per unit surface area. A smaller DSB means less dimethylsiloxane on the surface of the silica nanoparticles, and it does not inhibit fluidity as an external additive. However, because silanol groups tend to remain on the surface of the silica nanoparticle substrate, the effect of moisture in relatively humid environments cannot be suppressed, resulting in only a small improvement in charge retention. Conversely, a larger DSB (Double-Splitting Bound) results in a greater amount of dimethylsiloxane on the surface of silica nanoparticles, but an excess of D units can inhibit fluidity as an external additive.

[0028] Specifically, the DSB is 5.7 × 10 -4 If the DSB is below this level, the surface treatment of the silica nanoparticles is insufficient, and the toner's charge retention significantly decreases in relatively high humidity environments, resulting in ghosting. Also, if the DSB is 56 × 10 -4 If the amount exceeds a certain level, the amount of dimethylsiloxane becomes excessive, and the fluidity of the toner decreases significantly. Furthermore, in low humidity environments, excessive charging of the toner occurs. Furthermore, electrostatic aggregation occurs, significantly reducing the toner's fluidity, which lowers its charge retention and makes ghosting more likely. DSB is 5.7 x 10 -4 The above 49 x 10 -4 The following is preferable: 7.1 × 10 -4 The above 49 x 10 -4 The following are preferable.

[0029] DSB can be increased by increasing the amount of surface treatment agent used during the surface treatment of the silica nanoparticle substrate, or by selecting compounds with many D units, such as polydimethylsiloxane or cyclic siloxane, as the surface treatment agent. On the other hand, DSB can be decreased by decreasing the amount of surface treatment agent used during the surface treatment of the silica nanoparticle substrate, or by selecting compounds without D units, such as hexamethyldisiloxane, as the surface treatment agent.

[0030] Therefore, the silica nanoparticles are surface-treated with an appropriate amount of D units, and the amount of silanol on the surface of the silica nanoparticles is controlled within an appropriate range. On the other hand, let's discuss DSB-W. As mentioned above, DSB-W is the DSB after washing silica nanoparticles with chloroform. This value represents the amount of silicon atoms with D units that are chemically bonded to the silica nanoparticles. DSB-W is 1.7 x 10 -4 If the amount falls below this level, the amount of surface treatment agent bound to the surface of the silica microparticles is insufficient. During long-term use, the surface treatment agent on the silica microparticles may peel off, significantly reducing the toner's charge retention and causing ghosting. 56×10 -4 Beyond a certain point, fluidity tends to decrease, and in particular, in low-humidity environments, the fluidity decreases significantly due to excessive charging of the toner, leading to reduced charge retention and an increased likelihood of ghosting. DSB-W has a lower limit of 4.9 × 10⁻⁶. -4 The above is preferable, 6.0 × 10 -4 The above is preferable. The upper limit is 49 × 10 -4 The following is preferable: 33 × 10 -4 The following are preferable. In this specification, ZZ×10 -4 is ZZ×10 -3 It is synonymous with 33 × 10 -4 3.3 × 10 -3 It is synonymous with [the above].

[0031] Here, we define D1 as the polar group at the end of the structure derived from the surface treatment agent of silica nanoparticles. D1 is a solid, which will be described later. 29In the chemical shift obtained by Si-NMR, this corresponds to a peak whose peak top is located in the range between -19 ppm and -17 ppm. In silica nanoparticles treated with D units, D1 represents the polar group at the end of the D unit and has the structure shown in formula (8) below. D1: -Si-OR 3 ...(8) (R in equation (8)) 3 (This is a methyl group, an ethyl group, or a hydrogen atom.)

[0032] As a result of diligent research by the inventors, we have found that silica nanoparticles having an appropriate amount of D units and silanol have good charge retention regardless of the environment and can suppress ghosting when D1 is present in an appropriate amount.

[0033] The inventors speculate that the effect of D1 is as follows: Compared to polar groups such as silanol groups in Q units present on the surface of the silica nanoparticle substrate, the polar group D1 at the D unit terminus has moderately high hydrophobicity. This is thought to be due to the hydrophobicity derived from the carbon atoms bonded to Si. The moderately hydrophobic polar group at the D unit end has the effect of imparting electrostatic properties to its hydrophobic end. In addition, the D1 polar group at the D unit end is moderately more hydrophobic than the silanol group present on the surface of the silica nanoparticle substrate. Furthermore, as represented by DSB-W, the D unit is bound to the silica nanoparticle substrate to a certain extent, while the D1 at the D unit end is located away from the surface of the silica nanoparticle substrate. Therefore, the D1 at the D unit end is less affected by moisture in the silica nanoparticles, making it easier to maintain good electrostatic properties.

[0034] Based on the above, the surface of silica nanoparticles is treated with a treatment agent having D units, and silica nanoparticles By controlling the amount of silanol groups on the surface to an appropriate level and introducing a certain amount of D1 at the D unit end, it is possible to provide a toner that exhibits excellent charge retention and fluidity, as well as suppression of ghosting, in both normal temperature and humidity environments, and high temperature and low humidity environments, by setting the amount of silanol groups, DSB, DSB-W, and D1 / D in the silica nanoparticles to an appropriate range.

[0035] Therefore, solid silica nanoparticles 29 In the chemical shift obtained by the Si-NMR DD / MAS method, D1 is defined as the area of ​​the peak whose peak top is located in the range between -19 ppm and -17 ppm. The ratio of D1 to D (D1 / D) is between 0.10 and 0.30. solid 29 In Si-NMR measurements, the D-unit peak is separated into two. In the chemical shift, the peak appearing in the range between -19 ppm and -17 ppm is defined as peak D1, and the peak appearing in the range between -23 and -19 ppm is defined as peak D2.

[0036] In silica nanoparticles, the Si atoms bonded to the functional groups at the end of the D units are known to correspond to peak D1. Furthermore, the Si atoms within the dimethylsiloxane chain are known to correspond to peak D2. Therefore, a larger integral value of peak D1 indicates a greater number of terminal polar groups in the D units. In other words, D1 / D represents the amount of polar groups in the D units of the treatment agent. A larger D1 / D indicates a treatment state with a greater number of terminal polar groups in the D units.

[0037] If D1 / D falls below 0.10, the amount of polar groups is low, resulting in insufficient charging in a normal temperature and humidity environment, reduced charge retention, and ghosting. Conversely, if D1 / D exceeds 0.30, the amount of polar groups is high, leading to excessive charging, especially in low humidity environments. D1 / D is preferably 0.10 or higher, and more preferably 0.18 or higher. On the other hand, the upper limit is preferably 0.25 or lower, and more preferably 0.22 or lower.

[0038] The D1 / D ratio originates from the structure of the treatment agent used to treat the surface of silica nanoparticles, and can therefore be controlled by the type of treatment agent, the amount added, and the reaction conditions. For example, it is preferable to use a treatment agent that has a large amount of D1 structure, or to use a cyclic siloxane that opens its ring and reacts with the surface of silica nanoparticles, such as octamethyltetrasiloxane, or a low molecular weight polydimethylsiloxane.

[0039] Furthermore, the D1 / D ratio can be increased by adjusting the reaction conditions (temperature, time) of the surface treatment agent to conditions that generate Si-OH. On the other hand, the D1 / D ratio can be decreased by using a treatment agent that does not have a D1 structure and treating under conditions that prevent the formation of a D1 structure. For example, this can be done by treating with hexamethyldisilazane or by physically attaching polydimethylsiloxane.

[0040] The surface of the toner particles contains a vinyl resin having a structure represented by the following formula (9) (preferably an alkoxycarbonyl group having 1 to 10 carbon atoms (preferably 1 to 8, more preferably 2 to 6)). That is, the toner contains a vinyl resin having an alkoxycarbonyl group on the surface of the toner particles. In formula (9), R 4 This is a hydrocarbon group (preferably an alkyl group) having 1 to 10 carbon atoms (preferably 1 to 8, more preferably 2 to 6).

[0041] The presence of such a vinyl resin on the surface of toner particles significantly improves the electrostatic stability when combined with toner particles, in which silica has the fragment ions of formula (1) and satisfies the above-mentioned range of D1 / D, DSB, DSB-W, Sn. This is because the Si-OR groups (R is a hydrogen atom, methyl group, or ethyl group) such as the silanol groups of silica nanoparticles become polarized, and Si-O δ- R δ+ Having polarity as described above gives it the ability to impart charge. On the other hand, the structure of equation (9) above is also easily polarized and has excellent charging properties, but it is prone to overcharging in low humidity environments.

[0042] According to our research, the combination with the above-mentioned silica nanoparticles exhibited excellent electrostatic properties while tending to prevent excessive charging in low-humidity environments. We believe this is because the polarization structure of the Si-OR groups on the surface and the polarization structure of the structure shown in equation (9) interact electrostatically, causing the polarization to spread and the charged area to expand, thereby preventing localized excessive charging. [ka]

[0043] Furthermore, when Sa (area %) is the percentage of the structure represented by formula (9) on the surface of the toner particles, Sa is preferably 50 area % or more. More preferably 70 area % or more, and even more preferably 90 area % or more. There is no particular upper limit, but it is preferably 100 area % or less and 99 area % or less. Sa can be controlled by the structure of resins that may be present on the surface of the toner particles, such as binder resins, or by actively providing a shell layer in the toner and further adjusting the structure of the shell layer. The presence of vinyl resin having the structure shown in equation (9) on the toner particle surface can be confirmed by TOF-SIMS. By mapping the areas where the structure shown in equation (9) is detected by TOF-SIMS and calculating the ratio to the analyzed area, the area ratio of the toner particle surface can be calculated. Detailed procedures will be described later.

[0044] When the coverage rate of silica fine particles on the surface of toner particles, calculated from scanning electron microscope (SEM) images of the toner surface, is defined as Ssi, it is preferable that Ssi is 30 to 100 area percent. If the coverage rate is 30 area percent or more, the effect of static charge retention can be sufficiently obtained. The lower limit of Ssi is preferably 30 area% or more, more preferably 35 area% or more, and even more preferably 40 area% or more. The upper limit is preferably 90 area% or less, more preferably 80 area% or less, even more preferably 60 area% or less, and even more preferably 50 area% or less. The Ssi coverage can be controlled by the amount of silica fine particles added to the toner.

[0045] The ratio of the abundance Sa to the coverage Ssi (Sa / Ssi) is preferably 0.25 to 3.00. When Sa / Ssi is within the above range, the silica nanoparticles tend to suppress overcharging due to the structure shown in equation (9) in low humidity environments through interaction, and the chargeability in low humidity environments is improved without impairing the chargeability in normal temperature and humidity environments. The lower limit of Sa / Ssi is preferably 0.50 or higher, more preferably 1.50 or higher, and even more preferably 2.00 or higher. The upper limit is preferably 2.80 or lower, more preferably 2.50 or lower, and even more preferably 2.40 or lower.

[0046] Furthermore, the silica fine particle content is preferably 0.3 to 2.0 parts by mass, more preferably 0.4 to 1.2 parts by mass, and even more preferably 0.5 to 0.9 parts by mass per 100 parts by mass of toner particles. By setting the silica fine particle content within the above range, it becomes easier to control the coverage rate of the silica fine particles on the toner particles to a desired range.

[0047] Furthermore, the number-average particle size of the primary particles of the silica fine particles is preferably 5 to 50 nm, more preferably 10 to 40 nm, and even more preferably 20 to 30 nm. By adding silica microparticles within the above particle size range to the toner particles, it becomes easier to achieve improved toner fluidity, charge retention, and ghost suppression.

[0048] The silica microparticles preferably contain both small-particle and large-particle silica microparticles. The number-average particle size of the primary particles of the small-particle silica microparticles is preferably 5 to 25 nm, and more preferably 10 to 20 nm. The number-average particle size of the primary particles of the large-particle silica microparticles is preferably greater than 25 nm and 50 nm or less, and more preferably 30 to 40 nm. The BET specific surface area of ​​small-particle silica nanoparticles is 100-500 m². 2 It is preferable that the amount be / g, and 150-300m 2 It is more preferable that the amount is / g. Also, the BET specific surface area of ​​large-particle silica fine particles is 10 to 100 m².2 It is preferable that the amount be / g, and 30-80m 2 It is more preferable that it be / g. The mass-based content ratio of small-particle silica particles to large-particle silica particles is preferably 20:1 to 5:1, and more preferably 15:1 to 7:1. Furthermore, the BET specific surface area B of the silica nanoparticles after surface treatment is 40-200 m². 2 It is preferable that the amount be / g, and 100-150m 2 It is more preferable that it be / g.

[0049] From the viewpoint of further suppressing overcharging of silica nanoparticles in low humidity environments, it is preferable to use a combination of small-particle and large-particle silica nanoparticles. Specifically, when the ratio of particle size to the number-average particle size of the primary particles is 1.2 to 2.5 for large-particle silica and small-particle silica, it is easier to impart good developability and chargeability in the electrophotographic process.

[0050] Furthermore, it is preferable from the viewpoint of charge uniformity that small-particle and large-particle silica nanoparticles undergo similar surface treatment. The number-average particle size of the silica nanoparticles can be controlled by the mixing ratio of small-particle and large-particle silica nanoparticles, and the number-average particle size of each.

[0051] It is more preferable that the silica nanoparticles are surface-treated with at least the compound represented by the following formula (3). [ka]

[0052] In equation (3), R 1 , R 2 Each of these is independently a carbinol group, a hydroxyl group, an epoxy group, a carboxyl group, an alkyl group (preferably having 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms), or a hydrogen atom. m is the average number of repeating units and is an integer from 1 to 200 (preferably 30 to 150, more preferably 70 to 130).

[0053] The surface treatment agent of formula (3) can further improve charge retention and suppress ghosting. 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. Alternatively, two or more surface treatment agents with different functional groups may be used sequentially or in mixture, or two or more surface treatment agents having the same functional group but different viscosity and molecular weight distribution may be used sequentially or in mixture. It may also be used in this way.

[0054] When silica fine particles are washed with chloroform, the carbon content immobilization rate (C content immobilization rate) is preferably 30-70%, more preferably 50-70%, and even more preferably 60-65%. The carbon elements contained in silica nanoparticles originate from the carbon in the surface treatment agent and can be controlled by changing the structure of the surface treatment agent and the treatment conditions (treatment temperature, treatment time, viscosity, amount added, etc.). Here, the carbon-based immobilization rate of the surface treatment agent corresponds to the amount of surface treatment agent chemically bonded to the surface of the silica nanoparticle substrate. By controlling the carbon content immobilization rate using a surface treatment agent within the above range for silica microparticles, the coefficient of friction between the silica microparticles and the components inside the toner cartridge becomes appropriate. Furthermore, reducing the amount of silanol groups on the surface of the silica microparticle substrate makes it easier to control the D1 / D ratio, and thus makes it easier to suppress overcharging in low-humidity environments. As a result, better results can be obtained in terms of charge stability and ghosting suppression.

[0055] The carbon content (C content) of silica fine particles, as measured by a carbon-sulfur analyzer, is preferably 1.5 to 8.0 mass%, more preferably 2.5 to 7.0 mass%, even more preferably 3.5 to 6.0 mass%, and even more preferably 4.0 to 5.5 mass%.

[0056] The toner preferably contains strontium titanate fine particles in addition to silica fine particles on the surface of the toner particles. The ratio of the silica fine particle content to the strontium titanate fine particle content (Si / Sr) in the toner, as determined by X-ray fluorescence analysis, is preferably 0.2 to 2.5, more preferably 0.3 to 1.5, and even more preferably 0.4 to 1.0. The presence of strontium titanate microparticles on the toner surface improves the toner's charge retention and further suppresses ghosting. By controlling the Si / Sr ratio within the above range, charge retention is further enhanced and ghosting is suppressed even more effectively. The content ratio of silica particles to strontium titanate is calculated from the signal intensity ratio of Si atoms and Sr atoms in strontium titanate obtained by X-ray fluorescence analysis of the toner. The measurement method for X-ray fluorescence analysis will be described later.

[0057] The content of strontium titanate fine particles in the toner is preferably 0.01 to 2.00 parts by mass, more preferably 0.50 to 1.50 parts by mass, and even more preferably 0.80 to 1.20 parts by mass, per 100 parts by mass of toner particles.

[0058] The toner particles may contain a colorant. Any colorant can be used. Examples of colorants include organic pigments, organic dyes, and inorganic pigments, but there are no particular limitations, and any known colorant can be used. Among these, the use of a magnetic material is preferred. This is because, when a magnetic material is present on the surface of the toner particles, it not only acts as a colorant but also has the effect of moderately reducing the surface's electrostatic charge. The preferred amount to add is 30 parts by mass or more and 150 parts by mass or less per 100 parts by mass of the binder resin. In the present invention, the number-average particle size of the primary magnetic particles contained in the toner is preferably 500 nm or less, and more preferably 50 nm or more and 300 nm or less. The number-average particle size of primary magnetic particles present in toner particles can be measured using a transmission electron microscope.

[0059] Magnetic materials include iron oxides such as magnetite, maghemite, and ferrite; metals such as iron, cobalt, and nickel; or these metals combined with aluminum, copper, magnesium, tin, zinc, beryllium, calcium, manganese, selenium, titanium, tungsten, and vanadium. Examples include metal alloys and mixtures thereof. Furthermore, magnetic materials may be subjected to known surface treatments as needed.

[0060] The silica fine particles are preferably hydrophobized silica particles obtained by heat-treating a silica fine particle substrate with a cyclic siloxane, followed by heat-treating with silicone oil. The ratio (X / Y) of the amount of cyclic siloxane treated X to the amount of silicone oil treated Y is preferably 0.60 to 1.20, more preferably 0.60 to 1.10, and even more preferably 0.70 to 1.00. By controlling X / Y within the above range, it becomes easier to control the value of D1 / D within the desired range. X / Y can be calculated using the following formula. X / Y = (C content of silica nanoparticles treated with cyclic siloxane : C content of intermediate) / {(C content of silica nanoparticles treated with cyclic siloxane and then with silicone oil : C content of final product) - (C content of silica nanoparticles treated with cyclic siloxane : C content of intermediate)}

[0061] The amount of intermediate C is preferably 0.5 to 5.0 mass%, more preferably 1.0 to 4.0 mass%, even more preferably 1.5 to 3.0 mass%, and even more preferably 1.8 to 2.5 mass%. The final product C content is preferably 1.5 to 8.0% by mass, more preferably 2.5 to 7.0% by mass, even more preferably 3.5 to 6.0% by mass, and even more preferably 4.0 to 5.5% by mass.

[0062] The silica microparticle substrate that serves as the base material before surface treatment with silicone oil or the like can be any silica microparticle obtained by known methods without any particular limitations. For example, fumed silica, wet-process silica, and sol-gel silica are typical examples. Furthermore, these silica particles may be partially or entirely molten silica.

[0063] For the silica microparticle substrate, it is possible to appropriately select and use one from among fumed silica, wet silica, etc., depending on the required characteristics of the individual toner. In particular, fumed silica has excellent fluidity-imparting effects and is suitable as a silica microparticle substrate used as an external additive for electrophotographic toners.

[0064] Silica nanoparticles are used in which the silica nanoparticle substrate has been surface-treated to impart hydrophobicity and fluidity. Surface treatment methods include chemical treatment with silicon compounds that react with or physically adsorb to the silica nanoparticle substrate. The method for surface treatment of the silica microparticle substrate is not particularly limited and can be performed by bringing a surface treatment agent containing siloxane bonds into contact with the silica microparticles. From the viewpoint of uniformly treating the surface of the silica microparticle substrate and easily achieving the above physical properties, it is preferable to bring the surface treatment agent into contact with the silica microparticle substrate in a dry manner. As will be described later, examples include bringing the vapor of the surface treatment agent into contact with the silica microparticle raw material, or spraying the undiluted solution of the surface treatment agent or a diluted solution with various solvents into contact with the silica microparticle substrate.

[0065] As a surface treatment method for a silica microparticle substrate, the method for producing silica microparticles preferably comprises a first step of surface treatment (dry treatment) of the silica microparticle substrate with a cyclic siloxane, and a second step of surface treatment (dry treatment) of the silica microparticle substrate after cyclic siloxane treatment with silicone oil. The silica microparticles are preferably the silicone oil-treated product of the silica microparticles treated with cyclic siloxane. The method for producing toner preferably includes a step of preparing silica microparticles obtained by the above method.

[0066] Regarding the first treatment, high-temperature treatment with a low molecular weight cyclic siloxane can efficiently reduce the silanol groups on the surface of the silica nanoparticle substrate, and short dimethyl siloxanes with OH groups at the end can be used. Roxane chains can be added to the surface of silica nanoparticle substrates. The treatment temperature for cyclic siloxane on the surface of the silica nanoparticle substrate is preferably 300°C or higher. A temperature of 300°C or higher effectively reduces the silanol groups on the surface of the silica nanoparticle substrate. Furthermore, a treatment temperature of 300°C or higher allows for the formation and cleavage of siloxane bonds, enabling more uniform treatment of the silica nanoparticle substrate surface while uniformly controlling the siloxane chain length. The treatment temperature for the cyclic siloxane on the silica nanoparticle substrate surface is more preferably 310°C or higher, even more preferably 320°C or higher, and even more preferably 330°C or higher. There is no particular upper limit, but it is preferably 380°C or lower, and more preferably 350°C or lower.

[0067] After the above cyclic siloxane treatment, the silica nanoparticle substrate treated with the cyclic siloxane is heat-treated with silicone oil as a second treatment. The silicone oil binds to the terminal OH groups of the components reacted with the cyclic siloxane in the first treatment, allowing the long-chain dimethylsiloxane component to be introduced to the surface of the silica nanoparticles. The temperature during the silicone oil treatment of the silica nanoparticle substrate surface is preferably 300°C or higher, more preferably 320°C or higher, and even more preferably 330°C or higher. There is no particular upper limit, but it is preferably 380°C or lower, and more preferably 350°C or lower. By controlling the processing amount X of the cyclic siloxane and the processing amount Y of the silicone oil mentioned above, the silanol component on the surface of the silica microparticle substrate can be reduced, and the amounts of D units and D1 mentioned above can be controlled. This allows for improved electrostatic stability without reducing the fluidity of the toner with a small amount of surface treatment.

[0068] As the cyclic siloxane, at least one can be selected from the group consisting of low molecular weight cyclic siloxanes with up to 10 membered rings, such as hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, and decamethylcyclopentasiloxane. Among these, octamethylcyclotetrasiloxane is preferred. Furthermore, silicone oil refers to an oily substance having a molecular structure with siloxane bonds as its main chain, and any commonly available silicone oil that satisfies formula (3) above can be used without any particular restrictions. Specifically, examples include silicone oils consisting of a linear polysiloxane skeleton, such as dimethyl silicone oil, alkyl-modified silicone oil, olefin-modified silicone oil, fatty acid-modified silicone oil, alkoxy-modified silicone oil, polyether-modified silicone oil, and carbinol-modified silicone oil.

[0069] The processing time in the first and second processes varies depending on the processing temperature and the reactivity of the surface treatment agent used, but is preferably 5 minutes to 300 minutes, more preferably 30 minutes to 240 minutes, and even more preferably 50 minutes to 200 minutes. The above-mentioned processing temperature and processing time for the surface treatment are preferable from the viewpoint of allowing the treatment agent to react sufficiently with the silica fine particle substrate, and from the viewpoint of production efficiency.

[0070] In the first treatment, contact of the surface treatment agent with the silica microparticle substrate is preferably carried out by contacting the vapor of the surface treatment agent under reduced pressure or in an inert gas atmosphere such as a nitrogen atmosphere. By using the vapor contact method, it is possible to easily remove surface treatment agents that do not react with the silica microparticle surface and to appropriately coat the surface of the silica microparticles with modifying groups having appropriate polarity. When using the vapor contact method, it is preferable to perform the treatment at a treatment temperature above the boiling point of the surface treatment agent. The vapor contact may be carried out in multiple stages. When the vapor of a surface treatment agent is brought into contact with the surface under an inert gas atmosphere such as a nitrogen atmosphere, it is preferable that the pressure (gauge pressure) due to the vapor of the surface treatment agent in the container be 50 to 300 kPa or less, and more preferably 150 to 250 kPa.

[0071] The toner particles may contain a binder resin. Examples of binder resins include vinyl resins, polyester resins, polyethylene naphthalate resins, etc., but are not particularly limited and any known resin can be used. Preferably, the toner particles contain a vinyl resin as the binder resin. Specifically, vinyl resins that can be used include 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, styrene-maleic acid ester copolymer, and other styrene copolymers, as well as polyacrylic acid esters, polymethacrylate esters, polyvinyl acetate, etc. These can be used individually or in combination. Among these, styrene copolymers are particularly preferred.

[0072] The content of vinyl resin in the binder resin is preferably 50 to 100% by mass, more preferably 80 to 100% by mass, even more preferably 90 to 100% by mass, and even more preferably 95 to 100% by mass.

[0073] As polymerizable monomers capable of producing vinyl resins, vinyl monomers that can undergo radical polymerization are used. Monofunctional monomers or polyfunctional monomers can be used as the vinyl monomers. Examples of monofunctional monomers include styrene; styrene derivatives such as α-methylstyrene, β-methylstyrene, ο-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, and p-phenylstyrene; acrylic polymerizable monomers such as methyl acrylate, ethyl acrylate, n-propyl acrylate, iso-propyl acrylate, n-butyl acrylate, dibutyl phosphate ethyl acrylate, and 2-benzoyloxyethyl acrylate; methacrylic polymerizable monomers such as methyl methacrylate, ethyl methacrylate, and dibutyl phosphate ethyl methacrylate; methylene aliphatic monocarboxylic acid esters; vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, and vinyl isobutyl ether; and vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and vinyl isopropyl ketone.

[0074] Preferably, the vinyl resin is a copolymer of an alkyl (meth)acrylate having an alkyl group with 1 to 10 carbon atoms (preferably 1 to 8, more preferably 2 to 6) and styrene. More preferably, it is a copolymer of styrene and n-butyl acrylate. The amount of alkyl (meth)acrylate used in the copolymer as the binder resin can be used to control the abundance of the structure represented by formula (9).

[0075] A charge control agent may be added to the toner particles. Effective charge control agents for negative charging include organometallic complex compounds and chelate compounds, such as monoazo metal complex compounds, acetylacetone metal complex compounds, and metal complex compounds of aromatic hydroxycarboxylic acids or aromatic dicarboxylic acids. Examples of commercially available products include Spilon Black TRH, T-77, T-95 (Hodogaya Chemical Co., Ltd.), and BONTRON® S-34, S-44, S-54, E-84, E-88, E-89 (Orient Chemical Co., Ltd.).

[0076] Furthermore, it is preferable to use polymers or copolymers having sulfonic acid groups, sulfonic acid bases, or sulfonic acid ester groups as the charge-controlling resin. Alternatively, as a polymer having a sulfonic acid ester group, it is preferable to contain 2% by mass or more of a sulfonic acid group-containing acrylamide monomer or a sulfonic acid group-containing methacrylamide monomer in copolymerization ratio. More preferably, it contains 5% by mass or more in copolymerization ratio.

[0077] Preferably, the charge-controlled resin has a glass transition temperature (Tg) of 35°C to 90°C, a peak molecular weight (Mp) of 10,000 to 30,000, and a weight-average molecular weight (Mn) of 25,000 to 50,000. When this charge-controlled resin is used, desirable triboelectric properties can be imparted without affecting the thermal properties required for toner particles. Furthermore, because the charge-controlled resin contains sulfonic acid groups, the dispersibility of the charge-controlled resin itself and the dispersibility of the colorant in the colorant dispersion is improved, further enhancing coloring power, transparency, and triboelectric properties.

[0078] These charge control agents can be used individually or in combination of two or more. From the viewpoint of the toner's charge level, the amount of these charge control agents used is preferably 0.1 to 10.0 parts by mass per 100 parts by mass of binder resin, and more preferably 0.1 to 5.0 parts by mass.

[0079] When sulfonic acid-based resins and / or metal complex compounds are used as charge control agents, they tend to exhibit excellent properties in combination with silica fine particles, and are therefore preferred.

[0080] A release agent may be added to the toner particles as needed to improve adhesion. The release agent is not particularly limited, and known release agents can be used. Specifically, these include petroleum-based waxes such as paraffin wax, microcrystalline wax, and petrolactam, and their derivatives; montan wax and its derivatives; hydrocarbon waxes and their derivatives produced by the Fischer-Tropsch process; polyolefin waxes represented by polyethylene and polypropylene, and their derivatives; natural waxes such as carnauba wax and candelilla wax, and their derivatives; and ester waxes. Here, derivatives include oxides, block copolymers with vinyl monomers, and graft-modified products. Furthermore, as ester waxes, monofunctional ester waxes, difunctional ester waxes, and polyfunctional ester waxes such as tetrafunctional and hexafunctional waxes can be used.

[0081] The melting point of the release agent is preferably between 60°C and 140°C, and more preferably between 70°C and 130°C. A melting point between 60°C and 140°C makes it easier for the toner to plasticize during fixing, improving fixing performance. It is also preferable because it makes it less likely for the release agent to bleed out even after long-term storage.

[0082] In addition to silica microparticles and strontium titanate microparticles, other external additives such as inorganic external additives may be mixed with the toner particles and attached to the surface. Examples of inorganic external additives include hydrotalcite compounds, fatty acid metal salts, alumina, and metal oxide microparticles (inorganic microparticles) such as titanium dioxide, zinc oxide microparticles, cerium oxide microparticles, and calcium carbonate microparticles.

[0083] Furthermore, other external additives may include composite oxide nanoparticles using two or more metals, or two or more nanoparticles selected in any combination from these groups. Resin nanoparticles or organic-inorganic composite nanoparticles (resin nanoparticles and inorganic nanoparticles) may also be used. Other external additives may be hydrophobized using a hydrophobic treatment agent.

[0084] Examples of hydrophobic treatment agents include methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, t- Chlorosilanes such as butyldimethylchlorosilane and vinyltrichlorosilane; Tetramethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, o-methylphenyltrimethoxysilane, p-methylphenyltrimethoxysilane, n-butyltrimethoxysilane, i-butyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, dodecyltrimethoxysilane, tetraethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, i-butyltrimethoxysilane Alkoxysilanes such as tiltriethoxysilane, decyltriethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, and γ-(2-aminoethyl)aminopropylmethyldimethoxysilane; Silazanes such as hexaethyldisilazane, hexapropyldisilazane, hexabutyldisilazane, hexapentyldisilazane, hexahexyldisilazane, hexacyclohexyldisilazane, hexaphenyldisilazane, divinyltetramethyldisilazane, and dimethyltetravinyldisilazane; Silicone oils such as dimethyl silicone oil, methyl hydrogen silicone oil, methylphenyl silicone oil, alkyl-modified silicone oil, chloroalkyl-modified silicone oil, chlorophenyl-modified silicone oil, fatty acid-modified silicone oil, polyether-modified silicone oil, alkoxy-modified silicone oil, carbinol-modified silicone oil, amino-modified silicone oil, fluorine-modified silicone oil, and terminally reactive silicone oils; Siloxanes such as hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, hexamethyldisiloxane, and octamethyltrisiloxane; Examples of fatty acids and their metal salts include long-chain fatty acids such as undecylic acid, lauric acid, tridecylic acid, dodecylic acid, myristic acid, palmitic acid, pentadecylic acid, stearic acid, heptadecylic acid, arachidic acid, montanic acid, oleic acid, linoleic acid, and arachidonic acid, as well as salts of the above fatty acids with metals such as zinc, iron, magnesium, aluminum, calcium, sodium, and lithium.

[0085] Among these, alkoxysilanes, silazanes, and silicone oils are preferred because they facilitate hydrophobic treatment. These hydrophobic agents may be used individually or in combination of two or more. The content of other external additives is preferably 0.05 parts by mass or more and 20.0 parts by mass or less per 100 parts by mass of toner particles.

[0086] The weight-average particle size (D4) of the toner is preferably 3.0 μm to 12.0 μm, and more preferably 4.0 μm to 10.0 μm. When the weight-average particle size (D4) is within the above range, good fluidity is obtained, and the latent image can be developed faithfully.

[0087] The method for manufacturing toner is not particularly limited, and known manufacturing methods can be employed. Examples of toner manufacturing methods include grinding methods, polymerization methods, such as dispersion polymerization, association agglutination, dissolution suspension, suspension polymerization, and emulsification agglutination. The following are specific examples of pulverization methods for producing toner through a melting and kneading process and a pulverization process, but are not limited to these.

[0088] For example, a binder resin and, if necessary, colorants, release agents, charge control agents, and other additives. The ingredients are thoroughly mixed using a mixer such as a Henschel mixer or ball mill (mixing step). The resulting mixture is then melt-kneaded using a thermal kneader such as a twin-screw extruder, heated roll, kneader, or extruder (melt-kneading step).

[0089] After the obtained molten mixture is cooled and solidified, it is crushed using a pulverizer (crushing step) and then classified using a classifier (classification step) to obtain toner particles. Furthermore, if necessary, the toner particles and external additives are mixed using a mixer such as a Henschel mixer to obtain toner.

[0090] Examples of mixing machines include: FM mixer (Nippon Coke Industries Co., Ltd.); Super Mixer (Kawata Co., Ltd.); Ribocone (Okawara Seisakusho Co., Ltd.); Nauter mixer, Turbulizer, Cyclomix (Hosokawa Micron Co., Ltd.); Spiral Pin Mixer (Taiheiyo Kiko Co., Ltd.); Redigge mixer (Matsubo Co., Ltd.).

[0091] Examples of heat kneaders include: KRC kneader (manufactured by Kurimoto Iron Works); Buss-Co kneader (manufactured by Buss); TEM type extruder (manufactured by Toshiba Machine Co.); TEX twin-screw kneader (manufactured by Japan Steel Works); PCM kneader (manufactured by Ikegai Iron Works); three-roll mill, mixing roll mill, kneader (manufactured by Inoue Seisakusho); Nidex (manufactured by Mitsui Mining Co.); MS type pressure kneader, Nidaruder (manufactured by Moriyama Seisakusho); Banbury mixer (manufactured by Kobe Steel).

[0092] Examples of crushing machines include: counter jet mill, micron jet, inomizer (manufactured by Hosokawa Micron Co., Ltd.); IDS type mill, PJM jet crusher (manufactured by Nippon Pneumatic Mfg. Co., Ltd.); cross jet mill (manufactured by Kurimoto Iron Works Co., Ltd.); Ulmax (manufactured by Nisso Engineering Co., Ltd.); SK Jet-O-Mill (manufactured by Seishin Enterprise Co., Ltd.); Cryptron (manufactured by Kawasaki Heavy Industries, Ltd.); Turbo Mill (manufactured by Turbo Industries Co., Ltd.); and Super Rotor (manufactured by Nisshin Engineering Co., Ltd.).

[0093] Examples of classifiers include: Classil, Micron Classifier, Spedick Classifier (manufactured by Seishin Corporation); Turbo Classifier (manufactured by Nisshin Engineering Co., Ltd.); Micron Separator, Turboplex (ATP), TSP Separator (manufactured by Hosokawa Micron Corporation); Elbow Jet (manufactured by Nippon Steel Mining Co., Ltd.), Dispersion Separator (manufactured by Nippon Pneumatic Mfg. Co., Ltd.); and YM Microcut (manufactured by Yaskawa Trading Co., Ltd.).

[0094] Additionally, the following sieving devices may be used to separate coarse particles: Ultrasonic (manufactured by Koei Sangyo Co., Ltd.); Resona Sieve, Gyro Shifter (manufactured by Tokuju Kogyo Co., Ltd.); Vibrasonic System (manufactured by Dalton Co., Ltd.); Soniclean (manufactured by Shinto Kogyo Co., Ltd.); Turbo Screener (manufactured by Turbo Kogyo Co., Ltd.); Micro Shifter (manufactured by Makino Sangyo Co., Ltd.); Circular Vibrating Sieve.

[0095] Toner particles are manufactured by suspension polymerization, for example, as shown below. A polymerizable monomer composition is prepared by uniformly dissolving or dispersing polymerizable monomers, such as styrene monomers, (meth)acrylic acid ester monomers, colorants, wax components, and polymerization initiators, using a disperser such as a homogenizer, ball mill, or ultrasonic disperser, to produce a binder resin. After granulating the polymerizable monomer composition particles by dispersing the polymerizable monomer composition in an aqueous medium, toner particles are obtained by polymerizing the polymerizable monomers in the particles made of the polymerizable monomer composition.

[0096] In this case, it is preferable that the polymerizable monomer composition is prepared by mixing a dispersion in which a coloring agent is dispersed in a first polymerizable monomer (or a portion of the polymerizable monomers) with at least a second polymerizable monomer (or the remaining polymerizable monomers). That is, the coloring agent is dispersed in the first By thoroughly dispersing the colorant in polymerizable monomers and then mixing it with other toner materials and a second polymerizable monomer, the colorant can be present in polymerized particles in a better dispersed state.

[0097] Toner particles can be obtained by filtering, washing, drying, and classifying the polymerized particles using known methods. Toner can then be obtained by externally adding silica fine particles to the toner particles obtained as described above.

[0098] The addition of external additives such as silica microparticles to toner particles can be performed by mixing the toner particles and the external additive using a mixer like the one described below. Examples of mixing machines include: Henschel mixer (manufactured by Mitsui Mining Co., Ltd.); Super Mixer (manufactured by Kawata Co., Ltd.); Ribocone (manufactured by Okawara Seisakusho Co., Ltd.); Nauter mixer, Turbulizer, Cyclomix (manufactured by Hosokawa Micron Co., Ltd.); Spiral Pin Mixer (manufactured by Taiheiyo Kiko Co., Ltd.); and Redigge mixer (manufactured by Matsubo Co., Ltd.).

[0099] From the viewpoint of the dispersibility of the external additive, the mixing time in the external additive process is preferably adjusted to a range of 0.5 minutes to 10.0 minutes, and more preferably to a range of 1.0 minute to 5.0 minutes. The method for manufacturing toner comprises the steps of obtaining toner particles, preparing silica fine particles, and externally adding and mixing the silica fine particles to the obtained toner particles to obtain toner.

[0100] Next, we will describe the measurement methods for each physical property. <Solid silica microparticles> 29 Methods for calculating DSB, DSB-W, and D1 / D using Si-NMR DD / MAS measurement > Solid silica nanoparticles 29 Si-NMR measurements are performed by separating silica nanoparticles from the toner surface. Below, we will discuss the method for separating silica nanoparticles from the toner surface and the solid-state method. 29 This document describes Si-NMR measurements.

[0101] <Method for separating silica microparticles from the toner surface> When using silica microparticles separated from the surface of the toner as the measurement sample, the separation of silica microparticles from the toner is performed using the following procedure. Add 1.6 kg of sucrose (manufactured by Kishida Chemical Co., Ltd.) to 1 L of deionized water and dissolve it over a water bath to prepare a concentrated sucrose solution. Place 31 g of this concentrated sucrose solution and 6 mL of Contaminon N (a 10% by mass aqueous solution of a pH 7 neutral detergent for cleaning precision measuring instruments, consisting of a nonionic surfactant, anionic surfactant, and organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) into a centrifuge tube to prepare a dispersion. Add 10 g of toner to this dispersion and break up any clumps of toner with a spatula or similar tool. The centrifugation tube is placed in an Iwaki Sangyo Co., Ltd. "KM Shaker" (model: V.SX) and shaken for 20 minutes at a rate of 350 strokes per minute. After shaking, the solution is transferred to a 50 mL glass tube for the swing rotor and centrifuged in a centrifuge at 3500 rpm for 30 minutes.

[0102] After centrifugation, toner particles are present in the uppermost layer of the glass tube, while a mixture of inorganic microparticles, including silica microparticles, is present in the lower aqueous solution layer. The upper and lower aqueous solutions are separated and dried, obtaining toner particles from the upper layer and the inorganic microparticle mixture from the lower layer. The obtained toner particles are used to measure the abundance of the structure shown in equation (9) below. The centrifugation process is repeated so that the total amount of inorganic microparticle mixture obtained from the lower layer is 10 g or more.

[0103] Next, the dispersion containing 100 mL of deionized water and 6 mL of Contaminon N was obtained. Add 10 g of the inorganic fine particle mixture and disperse. Transfer the resulting dispersion to a 50 mL glass tube for a swing rotor and centrifuge at 3500 rpm for 30 minutes. After centrifugation, silica microparticles are present in the uppermost layer of the glass tube, while other inorganic microparticles are present in the lower aqueous solution layer. The upper aqueous solution is collected, and centrifugation is repeated as needed to ensure sufficient separation. After drying the dispersion, the silica microparticles are collected. Next, the solid silica microparticles recovered from the toner particles. 29 The Si-NMR measurement will be performed under the measurement conditions shown below.

[0104] <Solid 29 DD / MAS measurement conditions for Si-NMR measurement> Solid 29 The DD / MAS measurement conditions for Si-NMR measurement are as follows. Apparatus: JNM-ECX5002 (JEOL RESONANCE) Temperature: Room temperature Measurement method: DD / MAS method 29 Si 45° Sample tube: Zirconia 3.2 mm φ Sample: Filled in the test tube in powder form Sample rotation speed: 10 kHz Relaxation delay: 180 s Scan: 2000 Standard substance for calibration: DSS (Sodium 3-(trimethylsilyl)-1-propanesulfonate)

[0105] After the above measurement, from the solid Si-NMR spectrum of the silica fine particles 29 A plurality of silane components with different substituents and bonding groups are peak-separated into the following M unit, D unit, T unit, and Q unit by curve fitting. Curve fitting is performed using EXcalibur for Windows (registered trademark) version 4.2 (EX series) of the software for JNM-EX400 manufactured by JEOL Ltd. Click "1D Pro" from the menu icon to load the measurement data. Next, select "Curve fitting functinon" from "Command" in the menu bar to perform curve fitting. Curve fitting is performed for each component so that the difference (synthetic peak difference) between the synthetic peak obtained by synthesizing each peak obtained by curve fitting and the peak of the measurement result is minimized. M unit: (R i )(R j )(R k )SiO 1 / 2 Formula (4) D unit: (R g )(R h )Si(O1 / 2 ) 2 Formula (5) T unit: R m Si(O 1 / 2 ) 3 Formula (6) Q unit: Si(O 1 / 2 ) 4 Formula (7) In the formulas (4), (5), and (6), R i , R j , R k , R g , R h , R m represents an alkyl group such as a hydrocarbon group having 1 to 6 carbon atoms bonded to silicon, a halogen atom, a hydroxy group, an acetoxy group, or an alkoxy group, etc.

[0106] Also, for the D unit peak, waveform separation is performed individually by a fork function, and the area of peak D1 in the range exceeding -19 ppm and not exceeding -17 ppm is calculated. After peak separation, the integral value of the D unit present in the range of -25 to -15 ppm in chemical shift and the total sum S of all integral values of the M, D, T, and Q units present in the range of -140 to 100 ppm are calculated, and the BET specific surface area B (m 2 / g) of the silica fine particles is obtained by the method described later, and the ratio (D / S) / B is calculated. Also, the ratio D1 / D is calculated from the integral values of peaks D1 and D obtained by waveform separation. Furthermore, after performing the cleaning operation with chloroform shown below on the silica fine particles, the same NMR measurement is performed to calculate (D / S) / B after cleaning.<>

[0107] <Cleaning of Silica Fine Particles with Chloroform> Put 100 mL of chloroform and 1 g of silica fine particles into a centrifuge tube, and stir with a spatula or the like. Set the centrifuge tube on a KM Shaker and shake for 20 minutes under the condition of 350 reciprocations per minute. After shaking, transfer it to a glass tube for a swing rotor and perform centrifugation in a centrifuge under the conditions of 3500 rpm for 30 minutes. Discard the supernatant, add 100 mL of chloroform again, shake, and perform the centrifugation operation twice. Collect the precipitated silica fine particles and perform vacuum drying at 40 °C for 24 hours to obtain the silica fine particles after cleaning.

[0108] <Method for measuring fragment ions on the surface of silica nanoparticles using time-of-flight secondary ion mass spectrometry (TOF-SIMS)> TOF-SIMS measurement of silica nanoparticles is performed using silica nanoparticles separated from the toner surface by the method described above. For fragment ion measurement of the silica nanoparticle surface using TOF-SIMS, ULVAC-PHI's TRIFT-IV is used. The analysis conditions are as follows: Sample preparation: Silica microparticles are attached to an indium sheet. Primary ion: Au ion Acceleration voltage: 30kV Charge neutralization mode: On Measurement mode: Positive Raster: 200 μm Measurement time: 60s From the obtained mass profile of secondary ion mass / secondary ion charge (m / z), we check whether fragment ions corresponding to the structure shown in equation (1) are observed. For example, if the surface treatment agent is polydimethylsiloxane or cyclic siloxane, fragment ions are observed at positions such as m / z = 147, 207, and 221.

[0109] <Method for analyzing monomers in vinyl resin components> [Separation of resin components from toner] The toner is dissolved in tetrahydrofuran (THF), and the solvent is removed from the resulting soluble matter under reduced pressure to obtain the tetrahydrofuran (THF) soluble component of the toner. The obtained tetrahydrofuran (THF) soluble component of the toner is dissolved in chloroform to prepare a sample solution with a concentration of 25 mg / mL. 3.5 mL of the obtained sample solution is injected into the apparatus described below, and under the conditions described below, the low molecular weight component derived from the release agent (molecular weight less than 2000) and the high molecular weight component derived from the resin component (molecular weight 2000 or more) are separated. Preparative GPC device: Preparative HPLC LC-980 model manufactured by Japan Analytical Industry Co., Ltd. Preparative column: JAIGEL 3H, JAIGEL 5H (manufactured by Japan Analytical Industry Co., Ltd.) Eluent: Chloroform Flow rate: 3.5mL / min After separating the high molecular weight components derived from the resin components, the solvent is removed by distillation under reduced pressure, and the mixture is further dried under reduced pressure in a 90°C atmosphere for 24 hours. If high molecular weight components other than vinyl resins are present, it can be determined whether or not they are vinyl resins by performing monomer analysis of vinyl resins as shown below. Repeat the above procedure until approximately 100 mg of vinyl resin is obtained. Dry the obtained vinyl resin under reduced pressure at 40°C for 24 hours.

[0110] [Monomer analysis of vinyl resin components] The types of monomers for vinyl resin components are determined by the following conditions, based on samples of each resin component separated from the toner. The analysis will be performed using a pyrolysis GC / MS instrument. Measurement device: "Voyager" (product name, manufactured by ThermoElectron) Pyrolysis temperature: 600℃ Column: HP-1 (15m x 0.25mm x 0.25μm) Inlet: 300℃, Split: 20.0 Injection volume: 1.2mL / min Heating: 50℃ (4 min) - 300℃ (20℃ / min)

[0111] <Confirmation of vinyl resin having the structure shown in equation (9) on the surface of toner particles and method for measuring Sa using time-of-flight secondary ion mass spectrometry (TOF-SIMS)> TOF-SIMS measurement of the toner particle surface is performed using toner particles from which silica microparticles have been removed by the method described above for separating silica microparticles from the toner surface. For measuring fragment ions on the surface of silica nanoparticles using TOF-SIMS, we use the TRIFT-IV from ULVAC-PHI. The analysis conditions are as follows: Sample preparation: Toner particles are attached to an indium sheet. Primary ion: Au ion Acceleration voltage: 30kV Charge neutralization mode: On Measurement mode: Positive Raster: 200 μm Measurement time: 60s From the obtained mass profile of secondary ion mass / secondary ion charge number (m / z), we confirm whether fragment ions of the monomer species identified by the above monomer analysis and fragment ions with the structure shown in equation (9) are observed.

[0112] Under the above conditions, the polymethyl methacrylate (PMMA) film is measured, and the sum of peak intensities A corresponding to the structure shown in equation (9) is obtained. Then, using toner particles excluding the silica nanoparticles, the same measurement is performed, and the peak intensity B corresponding to the structure shown in equation (9) is obtained. Note that B is the arithmetic mean measured for 100 toner particles. Sa can be calculated using the following formula. Sa = B / A × 100 (%)

[0113] Furthermore, to determine whether a vinyl resin having the structure shown in formula (9) is present on the surface of the toner particles, if fragment ions of the monomer species identified by the above monomer analysis and fragments having the structure of formula (9) are observed, it is determined that a vinyl resin having the structure shown in formula (9) is present on the surface of the toner particles.

[0114] <Method for measuring the Si-OH content of silica nanoparticles> The Si-OH content of silica nanoparticles can be determined using the silica nanoparticles separated from the toner by the method described above, and then by the following method. Prepare sample solution 1 by mixing 25.0 g of ethanol and 75.0 g of a 20% sodium chloride aqueous solution. Also, prepare sample solution 2 by accurately weighing 2.00 g of silica fine particles into a glass bottle and adding a solvent mixture of 25.0 g of ethanol and 75.0 g of a 20% sodium chloride aqueous solution. Stir sample solution 2 with a magnetic stirrer for at least 5 minutes to disperse the silica fine particles. Next, for each of sample solutions 1 and 2, measure the pH change of the sample solution while adding a 0.1 mol / L sodium hydroxide aqueous solution dropwise at a rate of 0.01 mL / min. Record the volume (L) of sodium hydroxide aqueous solution added when the pH reaches 9.0. From the following formula, 1 nm 2 Si-OH content per unit Sn (particles / nm) 2 It is possible to calculate ). Sn = {(ab) × c × NA} / (d × e) a: NaOH titration volume (L) of sample solution 2 b: Volume of NaOH titration of sample solution 1 (L) c: Concentration of the NaOH solution used in the titration (mol / L) NA: Avogadro's number d: Mass of silica microparticles (g) e: BET specific surface area of ​​silica nanoparticles (nm) 2 / g: Specific surface area (m²) obtained below 2 (converted from / g)

[0115] <Method for measuring the specific surface area of ​​silica microparticles using the BET method> The BET specific surface area of ​​silica nanoparticles is measured using the following procedure. The measuring device employs the gas adsorption method by constant volume, and is called the "Automatic Specific Surface Area and Pore Distribution Measurement Device Tri". The "TriStar3000 (manufactured by Shimadzu Corporation)" will be used. The setting of measurement conditions and analysis of measurement data will be performed using the dedicated software "TriStar3000 Version 4.00" included with the device. A vacuum pump, nitrogen gas piping, and helium gas piping will also be connected to the device. Nitrogen gas will be used as the adsorption gas, and the value calculated by the BET multipoint method will be used as the BET specific surface area. The BET specific surface area is calculated as follows: First, nitrogen gas is adsorbed onto silica nanoparticles, and the equilibrium pressure P(P) inside the sample cell at that time is calculated. a ) and the amount of nitrogen adsorbed by the magnetic material V a (mol·g -1 ) is measured. Then, the equilibrium pressure P(P) in the sample cell is measured. a ) is the saturated vapor pressure P of nitrogen o (P a The relative pressure P is the value obtained by dividing by ). r With the horizontal axis representing the amount of nitrogen adsorption V, a (mol·g -1 An adsorption isotherm is obtained with ) as the vertical axis. Next, the monolayer adsorption amount V is the amount of adsorption required to form a monolayer on the surface of silica nanoparticles. m (mol·g -1 ) is calculated by applying the following BET formula. P r / V a (1-P r ) = 1 / (V m ×C)+(C-1)×P r / (V m ×C) (Here, C is the BET parameter, which is a variable that varies depending on the type of sample being measured, the type of adsorbed gas, and the adsorption temperature.) The BET formula uses P as the X-axis. r , Y axis P r / V a (1-P r If we assume that the slope is (C-1) / (V m ×C), the intercept is 1 / (V m This can be interpreted as a straight line (×C) (this line is called a BET plot). The slope of a line = (C-1) / (V m ×C) Intercept of a straight line = 1 / (V m ×C) P r Measured values ​​and P r / V a (1-P r By plotting the measured values ​​of ) on a graph and drawing a straight line using the least squares method, the slope and intercept values ​​of that line can be calculated. Solving the simultaneous equations for the slope and intercept using these values, we get V mAnd C can be calculated. Furthermore, V calculated above m and the molecular occupied cross-section of a nitrogen molecule (0.162 nm 2 ) Based on the following formula, the BET specific surface area S(m²) of silica nanoparticles is calculated. 2 Calculate the value (per g). S=V m ×N×0.162×10 -18 (Here, N is Avogadro's number (mol) -1 ) is. )

[0116] Measurements using this device are performed specifically according to the following procedure. Thoroughly wash and dry the dedicated glass sample cell (stem diameter 3 / 8 inch, volume 5 mL) and accurately weigh its tare. Then, using a funnel, place 0.1 g of silica microparticles into the sample cell. Place the sample cell containing the silica microparticles into the "Vacuprep 061 (Shimadzu Corporation)" pretreatment device, which is connected to a vacuum pump and nitrogen gas piping, and continue vacuum degassing at 23°C for 10 hours. During vacuum degassing, the valve is adjusted to gradually remove the silica particles while preventing them from being drawn into the vacuum pump. The pressure inside the cell gradually decreases as degassing progresses, eventually reaching 0.4 Pa (approximately 3 mTorr). After vacuum degassing is complete, nitrogen gas is gradually injected to return the sample cell to atmospheric pressure, and the sample cell is then opened. Remove the sample cell from the processing unit. Then, accurately weigh the sample cell and calculate the exact mass of the silica microparticles from the difference between the weighed and tare weights. During this process, the sample cell should be sealed with a rubber stopper to prevent contamination of the silica microparticles with moisture from the atmosphere.

[0117] Next, a special isothermal jacket is attached to the sample cell containing silica nanoparticles. Then, a special filler rod is inserted into the sample cell, and the sample cell is set into the analysis port of the apparatus. The isothermal jacket is a cylindrical component with a porous inner surface and an impermeable outer surface, capable of drawing up liquid nitrogen to a certain level by capillary action. Next, the free space of the sample cell, including the connecting device, is measured. The free space is calculated by first measuring the volume of the sample cell using helium gas at 23°C, then cooling the sample cell with liquid nitrogen and similarly measuring the volume of the sample cell using helium gas, and converting the difference between these volumes. The saturated vapor pressure of nitrogen P is also measured. o (P a ) is P built into the device o It is measured separately and automatically using a tube.

[0118] Next, after vacuum degassing the sample cell, the sample cell is cooled with liquid nitrogen while continuing vacuum degassing. Then, nitrogen gas is gradually introduced into the sample cell to adsorb nitrogen molecules onto the silica nanoparticles. At this time, the equilibrium pressure P(P) a By continuously measuring the adsorption isotherm, an adsorption isotherm can be obtained, and this adsorption isotherm is then converted into a BET plot. Note that the relative pressure P from which the data is collected r The points are set to a total of 6 points: 0.05, 0.10, 0.15, 0.20, 0.25, and 0.30. A straight line is drawn from the obtained measurement data using the least squares method, and the slope and intercept of that line are used to determine V m Calculate this V. m Using the value of , the BET specific surface area of ​​the silica nanoparticles is calculated as described above.

[0119] <Method for calculating the coverage ratio (Ssi) of toner particles by silica microparticles on the surface of toner particles> The coverage rate (Ssi) of silica microparticles on the surface of toner particles is calculated from backscattered electron images obtained by scanning electron microscopy (SEM). Backscattered electron images are also called "compositional images," and particles with smaller atomic numbers appear darker, while those with larger atomic numbers appear brighter. Backscattered electron images of toner are obtained under the following observation conditions. The method for obtaining backscattered electron images of toner and the method for calculating the coverage rate of silica microparticles on the surface of toner particles are described below.

[0120] <Method for obtaining backscattered electron images of toner> Equipment used: ULTRA PLUS manufactured by Carl Zeiss Microscopy Co., Ltd. Acceleration voltage: 1.0kV WD: 2.5mm Aperture Size: 30.0 μm Detection signal: EsB (Energy-selective backscattered electrons) EsB Grid: 700V Observation magnification: 20,000x Contrast: 63.0 ± 5.0% (reference value) Brightness: 38.0 ± 5.0% (reference value) Resolution: 1024 x 768 pixels Pre-treatment: Toner is sprayed onto carbon tape (Pt deposition is not performed). Contrast and brightness should be set appropriately according to the condition of the equipment being used. The acceleration voltage and EsB grid should be set to achieve objectives such as acquiring structural information of the toner's outermost surface, preventing charge-up of undeposited samples, and selectively detecting high-energy backscattered electrons. The observation field should be selected to cover areas with low toner curvature.

[0121] <Method for calculating the silica coating rate of toner> The silica coverage is determined by taking the backscattered electron image of the toner surface obtained by the above method and processing it using image processing software I. The data is obtained by analyzing it using mageJ (developed by Wayne Rashand). The procedure is as follows. First, convert the backscattered electron image to 8-bit using the Image menu's Type option. Next, reduce image noise by setting the Median diameter to 2.0 pixels using the Process menu's Filters option. Then, select the entire backscattered electron image using the Rectangle Tool on the toolbar. Subsequently, select Threshold from the Image menu's Adjust option and specify a luminance threshold (85-128 (256 gradations)) so that only luminance pixels originating from silica nanoparticles within the backscattered electrons are selected. Finally, select Measure from the Analyze menu to calculate the area percentage (area %) of the selected luminance portion in the backscattered electron image. The above procedure is performed for 20 fields of view for the toner to be evaluated, and the arithmetic mean is defined as the coverage rate (Ssi) of silica microparticles on the surface of the toner particles.

[0122] <Method for measuring the number-average particle size of silica microparticles> The number-average particle size of silica nanoparticles is measured from secondary electron images obtained by scanning electron microscopy (SEM) observation of the toner surface.

[0123] (Method for acquiring secondary electron images of toner) Equipment used: ULTRA PLUS manufactured by Carl Zeiss Microscopy Co., Ltd. Acceleration voltage: 1.0kV WD: 2.5mm Aperture Size: 30.0 μm Detection signal: SE2 (secondary electron image) Observation magnification: 50,000x Resolution: 1024 x 768 pixels Pre-treatment: Toner is sprayed onto carbon tape (Pt deposition is not performed). From the obtained secondary electron images, the longest diameter of 100 primary silica particles on the surface of the toner particles is measured, and the average value is taken as the number-average particle size of the silica particles. The distinction between silica nanoparticles and strontium titanate nanoparticles is made by elemental mapping using SEM-EDX.

[0124] <Method for measuring the carbon content of silica microparticles> The amount of carbon (C) derived from the hydrophobic treatment agent in silica microparticles is measured using a carbon-sulfur analyzer (product name: EMIA-320) manufactured by HORIBA Corporation. 0.3 g of silica nanoparticles, which are the sample, are accurately weighed and placed in the crucible for the carbon-sulfur analyzer described above. To this, 0.3 g ± 0.05 g of tin (replacement part number 9052012500) and 1.5 g ± 0.1 g of tungsten (replacement part number 9051104100) are added as combustion aids. Then, the silica nanoparticles are heated at 1100°C in an oxygen atmosphere according to the instruction manual provided with the carbon-sulfur analyzer described above. As a result, the hydrophobic groups derived from the hydrophobic treatment agent on the surface of the silica nanoparticles are thermally decomposed into CO2, and the amount of CO2 is measured. From the amount of CO2 obtained, the amount of carbon (mass %) contained in the silica nanoparticles is determined.

[0125] <Calculation of the carbon content immobilization rate of silica nanoparticles> (Washing with chloroform: Extraction of unimmobilized treatment agents) By using the method described above for separating silica microparticles from the toner surface, the silica microparticles separated from the toner can be used. Place 0.50 g of silica microparticles and 40 mL of chloroform in an Erlenmeyer flask, cover, and stir for 2 hours (using a magnetic stirrer). Then, stop stirring and let stand for 12 hours. Next, centrifuge and remove all of the supernatant liquid. Centrifugation was performed using a KOKUSAN centrifuge (product name: H-9R) with a Bn1 rotor and a Bn1 rotor polyethylene centrifuge. The procedure is performed using a tube under the conditions of 20°C, 10,000 rpm, and 5 minutes.

[0126] The centrifuged silica nanoparticles are placed back into an Erlenmeyer flask, 40 mL of chloroform is added, and the flask is covered and stirred for 2 hours (using a magnetic stirrer). After that, stirring is stopped and the flask is allowed to stand for 12 hours. Next, the supernatant is removed by centrifugation. This procedure is repeated two more times. The resulting sample is then dried in a constant temperature bath at 50°C for 2 hours. The pressure is then reduced to 0.07 MPa and the sample is dried at 50°C for 24 hours to allow the chloroform to evaporate completely.

[0127] (C amount measurement) As described above, the carbon content of silica microparticles washed with chloroform and the carbon content of silica microparticles before washing with chloroform are measured according to the "Method for Measuring the Carbon Content of Silica Microparticles" described above. The carbon content immobilization rate of silica microparticles can be calculated using the following formula. C content immobilization rate [%] = (C content of silica microparticles treated with chloroform / C content of silica microparticles before washing with chloroform) × 100

[0128] <Method for measuring the weight-average particle size (D4) of toner> The weight-average particle size (D4) of the toner is measured using the Coulter Multisizer, a precision particle size distribution analyzer with a pore electrical resistance method equipped with a 100 μm aperture tube. Using the "Beckman Coulter Multisizer 3" (registered trademark, manufactured by Beckman Coulter) and the accompanying dedicated software "Beckman Coulter Multisizer 3 Version 3.51" (manufactured by Beckman Coulter) for setting measurement conditions and analyzing measurement data, measurements are taken with an effective number of measurement channels of 25,000, and the measurement data is analyzed and calculated. The electrolytic aqueous solution used for measurement is prepared by dissolving special grade sodium chloride in deionized water to a concentration of approximately 1% by mass; for example, "ISOTON II" (manufactured by Beckman Coulter) can be used. Before performing measurements and analysis, configure the dedicated software as follows. In the dedicated software's "Change Standard Measurement Method (SOM)" screen, set the total count in control mode to 50,000 particles, the number of measurements to 1, and the Kd value to the value obtained using "Standard Particle 10.0 μm" (manufactured by Beckman Coulter). Press the Threshold / Noise Level measurement button to automatically set the threshold and noise level. Also, set the current to 1600 μA, the gain to 2, the electrolyte to ISOTON II, and check the box for flushing the aperture tube after measurement. In the dedicated software's "Pulse to Particle Size Conversion Settings Screen," set the bin spacing to logarithmic particle size, the particle size bins to 256 particle size bins, and the particle size range to 2 μm or more and 60 μm or less.

[0129] The specific measurement method is as follows: (1) Pour approximately 200 ml of the electrolytic solution into a 250 ml round-bottom glass beaker specifically designed for the Multisizer 3, set it on the sample stand, and stir the mixture with the stirrer rod at 24 revolutions per second in a counterclockwise direction. Then, use the "Aperture Tube Flash" function of the dedicated software to remove any dirt and air bubbles from inside the aperture tube. (2) Place approximately 30 ml of the electrolytic aqueous solution into a 100 ml flat-bottomed glass beaker, and add approximately 0.3 ml of a diluted solution of "Contaminon N" (a 10% by mass aqueous solution of a pH 7 neutral detergent for cleaning precision measuring instruments, consisting of a nonionic surfactant, anionic surfactant, and organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) diluted three times by mass with deionized water as a dispersant. (3) Two oscillators with an oscillation frequency of 50 kHz are built in with their phases shifted by 180 degrees, and a predetermined amount of deionized water is placed in the water tank of an ultrasonic dispersion device called "Ultrasonic Dispersion System Tetora150" (manufactured by Nikko Bios Co., Ltd.) with an electrical output of 120 W. Approximately 2 ml of the aforementioned Contaminon N is added to this water tank. (4) Set the beaker from (2) into the beaker fixing hole of the ultrasonic disperser, and ultrasonic Activate the disperser. Then, adjust the height of the beaker so that the resonance of the electrolytic solution at the liquid surface inside the beaker is maximized. (5) While irradiating the electrolytic aqueous solution in the beaker described in (4) with ultrasound, add approximately 10 mg of toner to the electrolytic aqueous solution in small amounts and disperse it. Continue the ultrasonic dispersion treatment for another 60 seconds. During ultrasonic dispersion, adjust the water temperature in the tank to be between 10°C and 40°C as appropriate. (6) Using a pipette, the electrolytic aqueous solution (5) containing the dispersed toner is dropped into the round-bottom beaker (1) placed in the sample stand, and the concentration is adjusted to approximately 5%. The measurement is then continued until the number of particles measured reaches 50,000. (7) Analyze the measurement data using the dedicated software attached to the device to calculate the weight average particle size (D4). When setting the dedicated software to graph / volume%, the "average diameter" on the analysis / volume statistical value (arithmetic mean) screen is the weight average particle size (D4).

[0130] <Method for Measuring the Content Ratio of Silica Fine Particles and Strontium Titanate> The ratio value (Si / Sr) of the content of silica fine particles in the toner to the content of strontium titanate fine particles is measured and calculated by X-ray fluorescence analysis (XRF). Pelletize the toner by the following press molding to obtain a sample, and quantify the Si atoms derived from the silica fine particles to be analyzed and the Sr atoms specific to the strontium titanate fine particles by the wavelength-dispersive X-ray fluorescence shown below. (i) Example of equipment used X-ray fluorescence analyzer 3080 (Rigaku Corporation) (ii) Sample preparation For sample preparation, use a sample press molding machine MAEKAWA Testing Machine (manufactured by MFG Co, LTD). Put 0.5 g of toner into an aluminum ring (model number: 3481E1), set the load to 5.0 tons, press for 1 minute, and pelletize it. (iii) Measurement conditions Measurement diameter: 10φ Measurement potential, voltage 50 kV, 50 - 70 mA 2θ angle 25.12° Crystal plate LiF Measurement time 60 seconds (iv) Derivation of the intensity ratio of Si element derived from silica fine particles Among the Si element intensities of the toner to be analyzed, in order to calculate the ratio of the Si element intensity derived from the silica fine particles, the same measurement is performed on the toner particles from which the silica fine particles on the toner surface have been separated by the above method. Intensity ratio of Si element derived from silica fine particles = (Si element intensity before silica separation - Si element intensity after silica separation) / (Si element intensity before silica separation) (v) Regarding the calculation method of the content ratio of silica fine particles and strontium titanate particles Content ratio of silica fine particles and strontium titanate particles (Si / Sr)= (Intensity of Si element × Ratio of Si element intensity derived from silica fine particles / Intensity of Sr element)

Example

[0131] Hereinafter, the present invention will be described more specifically with reference to production examples and examples, but these do not limit the present invention in any way. All parts in the following formulations represent parts by mass.

[0132] <Production Example of Silica Fine Particles 1> As small particle size inorganic fine particles, untreated dry silica (number average particle size of primary particles: 15 nm, BET specific surface area: 200 m 2 / g) and as large particle size inorganic fine particles, untreated dry silica (number average particle size of primary particles: 35 nm, BET specific surface area: 50 m 2 / g) were charged at a mass ratio of 10:1 and heated to 330 °C in a fluidized state by stirring. The inside of the reactor was replaced with nitrogen gas, and the reactor was sealed. Using a spray nozzle, octamethylcyclotetrasiloxane was sprayed and mixed as the first surface treatment agent until the gauge pressure reached 200 kPa. Then, heating and stirring were continued for 1 hour to carry out a coating treatment by reaction. After the treatment, the inside of the reaction system was replaced with a nitrogen atmosphere and heated to 330 °C again. Subsequently, as the second surface treatment agent, 10 parts of dimethyl silicone oil (KF-96-50CS manufactured by Shin-Etsu Chemical Co., Ltd.) was spray-treated with respect to 100 parts of untreated dry silica, and a coating treatment was similarly carried out for 1 hour to obtain silica fine particles 1. The physical property values of silica fine particles 1 are shown in Table 1. After the treatment, the inside of the reaction system was replaced with a nitrogen atmosphere and heated to 330 °C again. Subsequently, as the second surface treatment agent, 10 parts of dimethyl silicone oil (KF-96-50CS manufactured by Shin-Etsu Chemical Co., Ltd.) was spray-treated with respect to 100 parts of untreated dry silica, and a coating treatment was similarly carried out for 1 hour to obtain silica fine particles 1. The physical property values of silica fine particles 1 are shown in Table 1.

[0133] <Production Examples of Silica Fine Particles 2 to 6> Silica fine particles 2 to 6 were obtained in the same manner as in the production example of silica fine particles 1, except that the reaction time of the first surface treatment agent and the number of parts of the second surface treatment agent were changed as shown in Table 1. Regarding the structure of the second treatment component in Table 1, the structure of the substituent of the compound represented by formula (3) is shown.

[0134] <Manufacturing example of silica microparticles 7> Untreated dry silica as small-particle inorganic fine particles (number-average particle size of primary particles: 15 nm, BET specific surface area: 200 m²) 2 ( / g) and untreated dry silica as large-particle inorganic fine particles (number average particle size of primary particles 35 nm, BET specific surface area 50 m²) 2 Silica nanoparticles 7 were obtained in the same manner as in the example of silica nanoparticle 1, except that the amount of silica nanoparticles ( / g) was added in a mass ratio of 6:1.

[0135] <Example of manufacturing silica microparticle 8> Untreated dry silica as inorganic fine particles (number-average particle size of primary particles 15 nm, BET specific surface area 200 m²) 2 Silica nanoparticles 8 were obtained in the same manner as in the manufacturing example of silica nanoparticle 1, except that only ( / g) was added.

[0136] <Manufacturing examples of silica microparticles 9-15> Silica nanoparticles 9 to 15 were obtained in the same manner as the production example of silica nanoparticle 1, except that the second surface treatment agent was a carbinol-modified silicone oil (KF-6002, manufactured by Shin-Etsu Chemical Co., Ltd.), and the BET specific surface area of ​​the untreated dry silica to be added, the reaction time of the first surface treatment agent, and the amount of the second surface treatment agent were changed as shown in Table 1.

[0137] <Example of manufacturing silica microparticles 16> Untreated dry silica as inorganic fine particles (number-average particle size of primary particles 15 nm, BET specific surface area 200 m²) 2 The mixture ( / g) was added and heated to 290°C while being stirred to a fluid state. The reactor was sealed by purging the inside with nitrogen gas, and octamethylcyclotetrasiloxane was sprayed using a spray nozzle as the first surface treatment agent until the gauge pressure reached 100 kPa, and then mixed. After that, heating and stirring were continued for 1 hour to allow the reaction to complete the coating treatment. After the treatment, the reaction system was replaced with a nitrogen atmosphere and heated again to 290°C. Subsequently, as a second surface treatment agent, 15 parts of dimethyl silicone oil (KF-96-50CS, manufactured by Shin-Etsu Chemical Co., Ltd.) was sprayed onto 100 parts of untreated dry silica, and a similar coating treatment was carried out for 1 hour to obtain silica fine particles 16.

[0138] <Example of manufacturing silica microparticles 17> Untreated dry silica as inorganic fine particles (number-average particle size of primary particles 15 nm, BET specific surface area 200 m²) 2 The material ( / g) was added and heated to 250°C while being stirred to a fluid state. The reactor was sealed by purging the inside with nitrogen gas, and octamethylcyclotetrasiloxane was sprayed using a spray nozzle as the first surface treatment agent until the gauge pressure reached 100 kPa, and then mixed. After that, heating and stirring were continued for 1 hour to perform the coating treatment and obtain silica fine particles 17.

[0139] <Example of manufacturing silica microparticles 18> Untreated dry silica as inorganic fine particles (number-average particle size of primary particles 15 nm, BET specific surface area 200 m²) 2 The silica was added ( / g) and heated to 250°C while being stirred to a fluid state. The reactor was sealed by replacing the inside with nitrogen gas, and stirring and heat were continued to maintain the fluid state of the silica. 100 parts of untreated dry silica were sprayed with 30 parts of dimethyl silicone oil (Shin-Etsu Chemical Co., Ltd. KF-96-50CS), and a coating treatment was carried out for 1 hour to obtain silica fine particles 18.

[0140] <Manufacturing examples of silica microparticles 19-20> Silica nanoparticles 19-20 were obtained in the same manner as the production example of silica nanoparticles 15, except that the amount of dimethyl silicone oil and the processing temperature were changed as shown in Table 1.

[0141] <Example of manufacturing silica microparticles 21> Untreated dry silica as inorganic fine particles (number-average particle size of primary particles 15 nm, BET specific surface area 200 m²) 2The mixture ( / g) was added and heated to 250°C while being stirred to a fluid state. The reactor was sealed by purging the inside with nitrogen gas, and 25 parts hexamethyldisilazane were sprayed using a spray nozzle as the first surface treatment agent. The coating treatment was then performed by continuing heating and stirring for 1 hour to allow the reaction to proceed. After the treatment, the reaction system was replaced with a nitrogen atmosphere and heated again to 250°C. Subsequently, as a second surface treatment agent, 10 parts of dimethyl silicone oil (Shin-Etsu Chemical Co., Ltd. KF-96-50CS) was sprayed onto 100 parts of untreated dry silica, and a similar coating treatment was carried out for 1 hour to obtain silica fine particles 21.

[0142] <Example of manufacturing silica microparticles 22> Untreated dry silica as inorganic fine particles (number-average particle size of primary particles 15 nm, BET specific surface area 200 m²) 2 The silica ( / g) was added and heated to 250°C while being stirred to a fluid state. The reactor was sealed by purging the inside with nitrogen gas, and 25 parts hexamethyldisilazane was sprayed using a spray nozzle as the first surface treatment agent for 100 parts untreated dry silica. Then, heating and stirring were continued for 1 hour to coat the silica, and silica fine particles 22 were obtained.

[0143] <Examples of magnetic iron oxide production> Fe 2+ 50 liters of a ferrous sulfate aqueous solution containing 2.0 mol / L of ferrous sulfate was mixed and stirred with 55 liters of a 4.0 mol / L sodium hydroxide aqueous solution to obtain a ferrous salt aqueous solution containing ferrous hydroxide colloid. This aqueous solution was maintained at 85°C, and an oxidation reaction was carried out while blowing air at 20 L / min to obtain a slurry containing core particles.

[0144] The obtained slurry was filtered and washed with a filter press, and then the core particles were redispersed in water and reslurried. To this reslurry solution, sodium silicate was added at 0.20% by mass in terms of silicon per 100 parts by mass of the core particles, the pH of the slurry solution was adjusted to 6.0, and stirring was performed to obtain magnetic iron oxide particles having a silicon-rich surface. The obtained slurry was filtered, washed with a filter press, and further reslurried with ion-exchanged water. 500 g (10% by mass with respect to magnetic iron oxide) of ion-exchange resin SK110 (manufactured by Mitsubishi Chemical Corporation) was added to this reslurry solution (solid content: 50 g / L), and ion-exchange was performed by stirring for 2 hours. Thereafter, the ion-exchange resin was removed by filtration with a mesh, filtered and washed with a filter press, and dried and crushed to obtain magnetic iron oxide having a number average diameter of 0.23 μm.

[0145] <Production of silane compound> 30 parts of iso-butyltrimethoxysilane was added dropwise to 70 parts of ion-exchanged water while stirring. Thereafter, this aqueous solution was maintained at pH 5.5 and a temperature of 55°C, and hydrolysis was performed by dispersing it at a peripheral speed of 0.46 m / s for 120 minutes using a dispersing blade. Thereafter, the pH of the aqueous solution was adjusted to 7.0, and it was cooled to 10°C to stop the hydrolysis reaction. Thus, an aqueous solution containing a silane compound was obtained.

[0146] <Production of magnetic body 1> 100 parts of magnetic iron oxide was placed in a high-speed mixer (LFS-2 type manufactured by Fukae Powtec Co., Ltd.), and while stirring at a rotation speed of 2000 rpm, 8.0 parts of the aqueous solution containing the silane compound was added dropwise over 2 minutes. Thereafter, mixing and stirring were performed for 5 minutes. Next, in order to enhance the fixing property of the silane compound, it was dried at 40°C for 1 hour to reduce the moisture, and then the mixture was dried at 110°C for 3 hours to advance the condensation reaction of the silane compound. Thereafter, it was crushed and passed through a sieve with a mesh opening of 100 μm to obtain magnetic body 1.

[0147] <Production example of magnetic body 2> An aqueous solution containing ferrous hydroxide was prepared by mixing 1.00 to 1.10 equivalents of caustic soda solution relative to iron, an amount of P2O5 equivalent to 0.15% by mass relative to iron in terms of phosphorus, and an amount of SiO2 equivalent to 1.50% by mass relative to iron in terms of silicon. The pH of the aqueous solution was adjusted to 8.0, and the oxidation reaction was carried out at 85°C while blowing in air to prepare a slurry liquid containing seed crystals.

[0148] Next, an aqueous ferrous sulfate solution was added to the slurry in an amount of 0.90 to 1.20 equivalents relative to the initial amount of alkali (sodium component of caustic soda). The slurry was then maintained at pH 7.6, and the oxidation reaction was carried out while blowing air into it to obtain a slurry containing iron oxide. The resulting magnetic iron oxide particles were filtered using a filter press, washed with a large amount of water, and dried at 120°C for 2 hours. The resulting particles were then crushed to obtain magnetic material 2 with a volume-average particle size of 150 nm.

[0149] <Examples of manufacturing sulfonic acid group-containing resins> In a pressurized reaction vessel equipped with a reflux tubing, stirrer, thermometer, nitrogen inlet tube, dropping device, and vacuum device, 250 parts methanol, 150 parts 2-butanone, and 100 parts 2-propanol were added as solvents, along with 83 parts styrene, 10 parts 2-ethylhexyl acrylate, and 7 parts 2-acrylamido-2-methylpropanesulfonic acid as monomers. The mixture was then heated to reflux temperature while stirring. A solution of 3 parts 2,2'-azobis(2-methylbutyronitrile) diluted with 20 parts 2-butanone was added dropwise over 30 minutes, and stirring was continued for 5 hours. Then, a solution of 1 part 2,2'-azobis(2-methylbutyronitrile) diluted with 20 parts 2-butanone was added dropwise over 30 minutes, and stirring was continued for another 5 hours to complete the polymerization. After removing the polymerization solvent under reduced pressure, the obtained polymer was coarsely ground to less than 100 μm using a cutter mill equipped with a 150 mesh screen. The obtained sulfonic acid group-containing resin had a Tg of approximately 75°C.

[0150] <Example of toner particle 1 manufacturing> Toner particles were manufactured using the following procedure. (Preparation of the first water system medium) 353.8 parts of deionized water were mixed with 2.9 parts of sodium phosphate dodecahydrate and heated to 60°C while stirring using a TK-type homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). Then, a calcium chloride aqueous solution was prepared by adding 1.7 parts of calcium chloride dihydrate to 11.7 parts of deionized water, and a magnesium chloride aqueous solution was prepared by adding 0.5 parts of magnesium chloride to 15.0 parts of deionized water. The mixture was stirred to obtain a first aqueous medium containing a dispersion stabilizer.

[0151] (Preparation of polymerizable monomer compositions) • Styrene 75.0 parts n-butyl acrylate 25.0 parts 0.5 parts of 1-6 hexanediol diacrylate ·Magnetic material 1 95.0 parts • Sulfonic acid group-containing resin 1.0 part The above materials were uniformly dispersed and mixed using an attritor (manufactured by Mitsui Miike Chemical Machinery Co., Ltd.), then heated to 60°C. 15.0 parts of behenyl stearate wax (melting point 68°C) as an ester wax and 8.0 parts of paraffin wax (manufactured by Nippon Seiro Co., Ltd., HNP-9) as a hydrocarbon wax were added and mixed, and dissolved to obtain a polymerizable monomer composition.

[0152] (Preparation of the second water system medium) 166.8 parts of deionized water were mixed with 0.6 parts of sodium phosphate dodecahydrate and heated to 60°C while stirring with a paddle agitator. Then, a calcium chloride aqueous solution was added, which consisted of 2.3 parts of deionized water mixed with 0.3 parts of calcium chloride dihydrate, and stirring continued to obtain a second aqueous medium containing a dispersion stabilizer.

[0153] (granulation) The polymerizable monomer composition was added to the first aqueous medium described above. This granulated liquid was processed using a Cavitron (manufactured by Eurotech) at a rotor speed of 29 m / s for 1 hour to uniformly disperse and mix the mixture. Further, 7.0 parts of t-butyl peroxypivalate were added as a polymerization initiator, and the mixture was granulated at 60°C under an N2 atmosphere using a Creamix (manufactured by M-Technic) at a peripheral speed of 22 m / s for 10 minutes while stirring, to obtain a granulated liquid containing droplets of the polymerizable monomer composition.

[0154] (Polymerization / Distillation / Drying / External addition) The granulated liquid was added to the second aqueous medium described above, and the mixture was reacted at 74°C for 3 hours while being stirred with a paddle agitator. After the reaction was complete, the temperature was raised to 98°C and the mixture was distilled for 3 hours to obtain a reaction slurry. Subsequently, as a cooling step, water at 0°C was added to the reaction slurry, and the slurry was cooled from 98°C to 45°C at a rate of 100°C / min. After that, the temperature was raised further and the mixture was held at 50°C for 3 hours. The reaction slurry was then allowed to cool to room temperature at 25°C. The cooled reaction slurry was washed with hydrochloric acid, filtered, and dried to obtain toner particles with a weight-average particle size of 7.7 μm.

[0155] <Example of toner particle 2 manufacturing> [Example of toner manufacturing using the pulverization method] • Binding resin 100.0 parts (Styrene / n-butyl acrylate copolymer (styrene-acrylic resin with a mass ratio of styrene to n-butyl acrylate of 78:22; Mw=8500, Tg=58℃) ·Magnetic material 2 80.0 parts • Hydrocarbon wax 5.0 parts (Fischer-Tropsch wax, melting point 77°C) • Charge control agent 1.0 part (T-77: Manufactured by Hodogaya Chemical Industry Co., Ltd.) • Sulfonic acid group-containing resin 1.0 part After pre-mixing the above materials in an FM mixer (manufactured by Nippon Coke Industries Co., Ltd.), the mixture was then mixed at a rotation speed of 3.33S. -1The mixture was kneaded using a twin-screw extruder (PCM-30 model, manufactured by Ikegai Iron Works Co., Ltd.) with the temperature set to 120°C near the outlet of the mixture. The resulting mixture was cooled, coarsely ground in a hammer mill, and then ground in a mechanical pulverizer (T-250, manufactured by Turbo Industries Co., Ltd.). The resulting finely ground powder was classified using a multi-part classifier utilizing the Coanda effect. As a result, toner particles 2 with a weight-average particle size (D4) of 7.7 μm were obtained.

[0156] <Examples of toner particle manufacturing (3-5)> As a binder resin, polyethylene naphthalate resin (Teijin Corporation, TN8050SC) was mixed in addition to (or instead of) styrene / n-butyl acrylate copolymer so that the ratio of polyethylene naphthalate resin in the binder resin was 10% by mass, 50% by mass, and 100% by mass, respectively, to obtain binder resins for use in toner particles 3 to 5. Toner particles 3 to 5 were obtained in the same manner as in the production example of toner particle 2, except that each of the obtained binder resins was used.

[0157] <Example of Toner 1 manufacturing> Using an FM mixer (FM-10B manufactured by Nippon Coke Industries Co., Ltd.), a toner mixture was obtained by mixing 1:100 parts toner particles, 1:0.6 parts silica fine particles, and 1.00 part strontium titanate fine particles (number-average particle size 1.2 μm) for 180 seconds at a rotation speed of 3200 rpm. Subsequently, coarse particles were removed using a 300-mesh sieve (mesh opening 48 μm) to obtain toner 1.

[0158] <Manufacturing examples for toners 2-27> Except for changing the type of toner particles, the type of silica microparticles, the amount of silica microparticles added, and the amount of strontium titanate microparticles added as shown in Table 2, the same procedure as in the manufacturing example of toner 1 was performed to obtain toners 2 to 27.

[0159] <Example 1> The following evaluation was performed on Toner 1. For the evaluation, we used an HP LaserJet Enterprise M609dn with a modified process speed of 410 mm / sec. The evaluation paper used was Vitality (manufactured by Xerox, basis weight 75 g / cm²). 2 (Letter size) was used.

[0160] <Evaluation of static charge retention> After leaving the above-mentioned print test machine and toner cartridge filled with evaluation toner in a high-temperature, low-humidity environment of 30°C / 15%RH for more than one day, 1000 sheets of a horizontal line pattern, in which 4-dot horizontal lines were printed at 176-dot intervals, were printed using the print test machine. Subsequently, the same environment was left for 72 hours, and 100 sheets were printed. After printing 1000 sheets, after leaving the cartridge for 72 hours, and after printing 100 sheets after leaving it for 72 hours, the charge level (μC / g) of the toner on the developer carrier inside the toner cartridge was measured using a blow-off powder charge level measuring device TB-200 (manufactured by Toshiba Chemical Co., Ltd.) to evaluate the charge retention performance under high temperature and low humidity conditions. The smaller the rate of decrease in charge after 72 hours of storage, the better the toner's charge retention. The following criteria were established for evaluating the charge retention performance. The same evaluation was also performed under normal temperature and humidity conditions (25°C / 50%RH). [Evaluation Criteria] (Static resistance) (Charge after 72 hours of inactivity) / (Charge after 1000 prints) × 100 A: Over 90% B: 85% or more, less than 90% C: 80% to less than 85% D: 75% or more but less than 80% E: Less than 75%

[0161] <Ghost Rating> Using the above-mentioned image output test machine and toner cartridge filled with evaluation toner, the image in Figure 1 was produced. The image was output. Note that the image in Figure 1 allows for a rigorous evaluation of ghosting characteristics based on the quality of the toner's rise time. Specifically, when ghosting occurs, the density of the halftone area becomes distorted after the black band at the top is output. Ghosting was evaluated based on whether the distortion was visually apparent. [Evaluation Criteria] A: No traces of the ghost can be found. B: The shading corresponding to the black bars is faintly visible in the upper 1 / 3 of the image. C: The shading corresponding to the black bars is faintly visible in the upper half of the image. D: A faint grayscale corresponding to black bars is visible across the entire image. E: Clear variations in shading corresponding to the black belt are visible.

[0162] <Examples 2-19> The evaluation was carried out in the same manner as in Example 1, except that toners 2-19 were used. <Comparative Examples 1-8> The evaluation was carried out in the same manner as in Example 1, except that toners 20-27 were used.

[0163] [Table 1] In the table, for silica nanoparticles 1-7, the substrate BET / m 2 The / g column shows the BET specific surface area of ​​200m². 2 / g small particle size silica and 50m 2 Large particle size silica / g, small particle size silica: large particle size silica This indicates that silica was used in a mass ratio of 10:1 (6:1 for silica nanoparticles 7). Regarding the quantity, the example using hexamethyldisilazane shows the number of parts.

[0164] [Table 2] In the table, the column for formula (1) is marked "Observed" if fragment ions corresponding to the structure shown in formula (1) are observed during TOF-SIMS measurements. The column for vinyl resin is marked "Present" if vinyl resin having the structure shown in formula (9) is present on the surface of the toner particles. The toner particle size is the weight-average particle size (D4). The silica content is the silica fine particle content, and the TiSr content is the strontium titanate fine particle content; these are expressed in parts per 100 parts by mass of toner particles.

[0165] [Table 3]

[0166] This disclosure relates to the following configuration. (Composition 1) A toner containing toner particles and silica fine particles on the surface of the toner particles, In time-of-flight secondary ion mass spectrometry measurements of the silica nanoparticles, fragment ions corresponding to the structure shown in equation (1) below were observed. In formula (1) of TIFF0007881371000011.tif37153, n represents an integer greater than or equal to 1. When 2.00 g of the silica fine particles are 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, the Sn, defined as Sn = {(ab) × c × Na} / (d × e), satisfies the following equation (2). 0.05 ≤ Sn ≤ 0.20 ···(2) In formula (2), a is the amount of NaOH titration (L) required to adjust the mixture containing the dispersed silica particles to pH 9.0. b is the amount of NaOH titration (L) required to adjust a mixture of 25.0 g of ethanol and 75.0 g of 20% by mass NaCl aqueous solution to pH 9.0. c is the concentration (mol / L) of the NaOH solution used in the titration. NA is Avogadro's number, d is the mass (g) of the silica fine particles, e is the BET specific surface area (nm) of the silica nanoparticles. 2 / g) is Solid silica fine particles 29 In the chemical shift obtained by the Si-NMR DD / MAS method, D is the area of ​​the peaks with peak tops in the range of -25 to -15 ppm, S is the sum of the areas of the M, D, T, and Q unit peaks in the range of -140 to 100 ppm, and B is the specific surface area of ​​the silica nanoparticles. 2 When we set it to / g, The ratio of (D / S) to B, (D / S) / B, is 5.7 × 10 -4 ~56×10 -4 And, The (D / S) / B value measured after washing the silica microparticles with chloroform was 1.7 × 10⁻⁶. -4 ~56×10 -4 And, In the chemical shift, when D1 is defined as the area of ​​the peaks where the peak top is located in the range between -19 ppm and -17 ppm, The ratio of D1 to D (D1 / D) is between 0.10 and 0.30. A toner characterized in that a vinyl resin having the structure shown in the following formula (9) is present on the surface of the toner particles. TIFF0007881371000012.tif27153 (in formula (9), R 4 (This refers to a hydrocarbon group having 1 to 10 carbon atoms.) (Configuration 2) The toner according to configuration 1, wherein when the proportion of the structure represented by formula (9) on the surface of the toner particles is denoted as Sa (area %), Sa is 50 area % or more. (Composition 3) The toner according to configuration 1 or 2, wherein the number-average particle size of the primary particles of the silica fine particles is 5 to 50 nm. (Composition 4) The toner according to any one of configurations 1 to 3, wherein the coverage rate of the toner particles by the silica fine particles, calculated from the scanning electron microscope observation image of the surface of the toner, is Ssi (area %), and Ssi is 30 to 100 area %. (Composition 5) Let Sa (area %) be the percentage of the structure represented by formula (9) on the surface of the toner particles. When the coverage rate of the toner particles by the silica fine particles on the surface of the toner is calculated from the scanning electron microscope image of the toner surface, and this is expressed as Ssi (area %), The toner according to any of configurations 1 to 4, wherein the ratio of Sa to Ssi (Sa / Ssi) is 0.25 to 3.00. (Composition 6) The toner according to any one of configurations 1 to 5, wherein the silica fine particles are surface-treated with at least the compound represented by the following formula (3). R in formula (3) of TIFF0007881371000013.tif37153 1 , R 2 Each of these is independently a carbinol group, a hydroxyl group, an epoxy group, a carboxyl group, an alkyl group, or a hydrogen atom. m is the average number of repeating units and is an integer between 1 and 200. (Composition 7) The toner according to any one of configurations 1 to 6, wherein the carbon content fixation rate when the silica fine particles are washed with chloroform is 30 to 70%. (Composition 8) The toner according to any one of configurations 1 to 7, wherein the toner further has strontium titanate fine particles on the surface of the toner particles. (Composition 9) The toner according to any one of configurations 1 to 8, wherein the silica fine particles are a silicone oil-treated product of silica fine particles treated with a cyclic siloxane.

Claims

1. A toner containing toner particles and silica fine particles on the surface of the toner particles, In time-of-flight secondary ion mass spectrometry measurements of the silica nanoparticles, fragment ions corresponding to the structure shown in the following formula (1) were observed. In formula (1), n ​​represents an integer of 1 or more, When 2.00 g of the silica fine particles are 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, the Sn, defined as Sn = {(a-b) × c × Na} / (d × e), satisfies the following equation (2): 0.05 ≤ Sn ≤ 0.20 ... (2) In formula (2), a is the amount of NaOH titration (L) required to adjust the mixture containing the dispersed silica fine particles to pH 9.

0. b is the amount of NaOH titration (L) required to adjust the pH of a mixture of 25.0 g of ethanol and 75.0 g of 20% by mass NaCl aqueous solution to 9.

0. c is the concentration (mol / L) of the NaOH solution used in the titration. NA is Avogadro's number, d is the mass (g) of the silica fine particles, e is the BET specific surface area (nm) of the silica nanoparticles. ２ / g) and Solid silica fine particles ２９ In the chemical shift obtained by the Si-NMR DD / MAS method, D is the area of ​​the peaks with peak tops in the range of -25 to -15 ppm, S is the sum of the areas of the M, D, T, and Q units of the peaks in the range of -140 to 100 ppm, and B is the specific surface area of ​​the silica nanoparticles (m²). ２ When / g) The ratio of (D / S) to B, (D / S) / B, is 5.7 × 10 －４ ~56 x 10 －４ And, The (D / S) / B value measured after washing the silica microparticles with chloroform was 1.7 × 10⁻⁶. －４ ~56 x 10 －４ And, In the chemical shift, when D1 is defined as the area of ​​the peaks where the peak top is located in the range greater than -19 ppm and less than or equal to -17 ppm, The ratio of D1 to D (D1 / D) is between 0.10 and 0.

30. A toner characterized in that a vinyl resin having the structure shown in the following formula (9) is present on the surface of the toner particles. (In formula (9), R ４ (This refers to a hydrocarbon group having 1 to 10 carbon atoms.)

2. The toner according to claim 1, wherein when the proportion of the structure represented by formula (9) on the surface of the toner particles is Sa (area %), Sa is 50 area % or more.

3. The toner according to claim 1 or 2, wherein the number-average particle size of the primary particles of the silica fine particles is 5 to 50 nm.

4. The toner according to claim 1 or 2, wherein when the coverage rate of the surface of the toner particles by the silica fine particles, calculated from the scanning electron microscope observation image of the surface of the toner, is denoted as Ssi (area %), the Ssi is 30 to 100 area %.

5. Let Sa (area %) be the percentage of the structure represented by formula (9) on the surface of the toner particles. When the coverage rate of the silica fine particles on the surface of the toner particles, calculated from the scanning electron microscope observation image of the toner surface, is denoted as Ssi (area %), The toner according to claim 1 or 2, wherein the ratio of Sa to Si (Sa / Si) is 0.25 to 3.

00.

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

7. When the aforementioned silica fine particles are washed with chloroform, the carbon content immobilization rate is 30-70%. Toner according to claim 1 or 2.

8. The toner according to claim 1 or 2, wherein the toner further comprises strontium titanate fine particles on the surface of the toner particles.

9. The toner according to claim 1 or 2, wherein the silica fine particles are a silicone oil-treated product of silica fine particles treated with a cyclic siloxane.

10. The silica fine particles contain small-particle silica fine particles and large-particle silica fine particles, The number-average particle size of the primary particles of the small-particle silica nanoparticles is 5 to 25 nm. The number-average particle size of the primary particles of the large-particle silica nanoparticles is greater than 25 nm and less than or equal to 50 nm. The toner according to claim 1 or 2, wherein the mass-based content ratio of the small-particle silica microparticles and the large-particle silica microparticles (small-particle silica microparticles:large-particle silica microparticles) is 20:1 to 5:1.

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