Toner for electrostatic image development, electrostatic image developer, toner cartridge, process cartridge, image forming apparatus, and image forming method.

Abstract

To provide a toner for electrostatic charge image development that prevents fogging occurring when images are repeatedly formed.SOLUTION: A toner for electrostatic charge image development has: toner particles; and silica particles that are externally added to the toner particle, the silica particles including a nitrogen element-containing compound, in which when the volumes of pores having a pore diameter of 1 nm or more and 50 nm or less determined from the pore distribution curve of the nitrogen gas adsorption method before and after calcination at 350°C are defined as A and B, respectively, B / A is 1.2 or more and 5 or less, and B is 0.2 cm3 / g or more and 3 cm3 / g or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a toner for electrostatic image development, an electrostatic image developer, a toner cartridge, a process cartridge, an image forming apparatus, and an image forming method. [Background technology]

[0002] In electrophotographic image formation, toner is used as the image forming material. For example, toners containing toner particles with a binder resin and a colorant, and external additives added to these toner particles, are commonly used. Silica particles are frequently used as the external additive.

[0003] For example, Patent Document 1 discloses a hydrophobic silica powder in which (1) the degree of hydrophobicity is 50% or more, (2) the amount X extracted by a mixed solvent of methanol and an aqueous solution of methanesulfonic acid, which is 0.1% by mass or more of at least one compound selected from the group consisting of quaternary ammonium ions, monoazo complexes, and mineral acid ions, and (3) the amount Y extracted by water from X satisfies the following formula (I) Y / X < 0.15.

[0004] Furthermore, Patent Document 2 discloses "a silica powder comprising a plurality of silica particles in which a quaternary ammonium salt is introduced into a silica structure having a "Si-O" bond as a repeating unit."

[0005] Furthermore, Patent Document 3 discloses "charge-controlled particles for external use, comprising transport particles consisting of hydrophobic spherical silica fine particles with an average particle size of 20 to 500 nm obtained by hydrophobic treatment of the surface of hydrophilic spherical silica fine particles obtained by the sol-gel method, and a charge-controlling agent attached to the surface of the transport particles."

[0006] Furthermore, Patent Document 4 discloses "silica fine particles obtained by treating spherical hydrophobic silica fine particles having an average primary particle size of 0.01 to 5 μm with a compound selected from the group consisting of quaternary ammonium salt compounds, fluoroalkyl group-containing betaine compounds, and silicone oil."

[0007] Furthermore, Patent Document 5 discloses "particles obtained by treating silica fine particles with a degree of hydrophobicity of 80% or more with an amphoteric surfactant, and particles obtained by treating silica fine particles with a degree of hydrophobicity of 80% or more with a quaternary ammonium salt or a polymer having a quaternary ammonium group." [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2019-073418 [Patent Document 2] Japanese Patent Publication No. 2017-039618 [Patent Document 3] Japanese Patent Publication No. 2011-185998 [Patent Document 4] Japanese Patent Publication No. 2001-194825 [Patent Document 5] Japanese Patent Application Publication No. 09-166884 [Overview of the project] [Problems that the invention aims to solve]

[0009] The object of the present invention is to provide a toner for electrostatic image development having toner particles and silica particles containing a nitrogen element compound externally added to the toner particles, wherein when the silica particles have pore volumes of 1 nm to 50 nm in diameter, determined from the pore distribution curve of the nitrogen gas adsorption method before and after firing at 350°C, respectively, B / A is less than 1.2, or B is 0.2 cm³. 3 The objective is to provide an electrostatic image developing toner that suppresses fogging that occurs when repeatedly forming images, compared to when silica particles are less than 1g / g. [Means for solving the problem]

[0010] The means for solving the above problems include the following embodiments. <1> Toner particles and Silica particles added to the toner particles, containing a nitrogen-containing compound, where A and B are the pore volumes of pores with diameters of 1 nm to 50 nm, determined from the pore distribution curve of the nitrogen gas adsorption method before and after firing at 350°C, respectively, B / A is 1.2 to 5, and B is 0.2 cm³. 3 / g or more 3cm 3 Silica particles that are less than / g, A toner for developing electrostatically charged images. <2> The B / A ratio in the silica particles is 1.4 or more and 3 or less. <1> Toner for developing electrostatic images as described above. <3> In the silica particles, the value of B is 0.3 cm. 3 / g or more 1.8cm 3 / g or less <1> or <2> Toner for developing electrostatic images as described above. <4> The number-average particle diameter of the silica particles is between 10 nm and 200 nm. <1> ~ <3> A toner for developing electrostatic images as described in any one of the items. <5> The number-average particle diameter of the silica particles is between 10 nm and 80 nm. <4> Toner for developing electrostatic images as described above. <6> The nitrogen-containing compound in the silica particles is at least one selected from the group consisting of quaternary ammonium salts, primary amine compounds, secondary amine compounds, tertiary amine compounds, amide compounds, imine compounds, and nitrile compounds. <1> ~ <5> A toner for developing electrostatic images as described in any one of the items. <7> The average circularity of the silica particles is 0.60 or more and 0.96 or less. <1> ~ <6> A toner for developing electrostatic images as described in any one of the items. <8> The average circularity of the silica particles is 0.70 or more and 0.92 or less. <7> Toner for developing electrostatic images as described above. <9> The volume resistivity of the silica particles is 1.0 × 10⁻⁶. 7 Ωcm or greater: 1.0 × 10 11.5 It is less than or equal to Ωcm. <1> ~ <8> A toner for developing electrostatic images as described in any one of the items. <10> When the volume resistivity of the silica particles before and after firing at 350°C is denoted as Ra and Rb, respectively, the ratio of Ra / Rb is between 0.01 and 0.8. <1> ~ <9> A toner for developing electrostatic images as described in any one of the items. <11> The cross-polarization / magic angle rotation (CP / MAS) method for the silica particles 29 Chemical shift of -50 ppm in Si solid-state nuclear magnetic resonance (NMR) spectrum from -75pp m The integral value C of the signal observed within the range, and the chemical shift of -90 ppm. from -120pp m The ratio C / D of the integral value D of the observed signals within the range is between 0.10 and 0.75. The following is <1> ~ <10> A toner for developing electrostatic images as described in any one of the items. <12> The silica particles are Silica matrix particles, A structure comprising a surface covering at least a portion of the silica matrix particles, composed of reaction products of a trifunctional silane coupling agent, and in which a nitrogen-containing compound is adsorbed in at least a portion of the pores of the reaction products of the trifunctional silane coupling agent, has <1> ~ <11> A toner for developing electrostatic images as described in any one of the items. <13> <1> ~ <12> A electrostatic image developer containing the electrostatic image developing toner described in any one of the items. <14> <1> ~ <12> It contains the electrostatic image developing toner described in any one of the items, A toner cartridge that is attached to and detached from an image forming machine. <15> <13> The development means contains the electrostatic image developer described above, and develops the electrostatic image formed on the surface of the image holder as a toner image using the electrostatic image developer, A process cartridge that is attached to and detached from an image forming apparatus. <16> Image holder and, A charging means for charging the surface of the image holder, A means for forming an electrostatic image on the surface of the charged image holder, <13> A developing means containing the electrostatic image developer described above, and developing the electrostatic image formed on the surface of the image holder as a toner image using the electrostatic image developer, A transfer means for transferring a toner image formed on the surface of the image holder to the surface of a recording medium, A cleaning means having a cleaning blade for cleaning the surface of the image holder, Fixing means for fixing the toner image transferred to the surface of the recording medium, An image forming apparatus equipped with the following features. <17> A charging process to charge the surface of the image holder, A step of forming an electrostatic image on the surface of the charged image holder, <13> A developing step in which the electrostatic image formed on the surface of the image holder is developed as a toner image using the electrostatic image developer described above, A transfer step of transferring the toner image formed on the surface of the image holder to the surface of the recording medium, A cleaning step in which the surface of the image holder is cleaned with a cleaning blade, A fixing step for fixing the toner image transferred to the surface of the recording medium, An image forming method having the following characteristics. [Effects of the Invention]

[0011] According to the invention according to <1>, there is provided an electrostatic charge image developing toner having toner particles and silica particles externally added to the toner particles and containing a nitrogen element-containing compound, wherein when the pore volumes of pores having a pore diameter of 1 nm or more and 50 nm or less obtained from the pore distribution curve of the nitrogen gas adsorption method before and after firing at 350 ° C. are A and B, respectively, for the silica particles, B / A is less than 1.2, or B is less than 0.2 cm 3 There is provided an electrostatic charge image developing toner that suppresses fogging that occurs when forming a repeated image as compared with the case of silica particles that are / g or less.

[0012] According to the invention according to <2>, there is provided an electrostatic charge image developing toner that suppresses fogging that occurs when forming a repeated image as compared with the case where B / A in the silica particles is less than 1.4. According to the invention according to <3>, there is provided an electrostatic charge image developing toner that suppresses fogging that occurs when forming a repeated image as compared with the case where B in the silica particles is less than 0.3 cm 3 / g or less.

[0013] According to the invention according to <4> or <5>, there is provided an electrostatic charge image developing toner having toner particles and silica particles externally added to the toner particles and containing a nitrogen element-containing compound, wherein when the pore volumes of pores having a pore diameter of 1 nm or more and 50 nm or less obtained from the pore distribution curve of the nitrogen gas adsorption method before and after firing at 350 ° C. are A and B, respectively, for the silica particles, B / A is less than 1.2, or B is less than 0.2 cm 3 There is provided an electrostatic charge image developing toner that suppresses fogging that occurs when forming a repeated image even when the number average particle diameter of the silica particles is 10 nm or more and 200 nm or less or 10 nm or more and 80 nm or less as compared with the case of silica particles that are / g or less.

[0014] According to the invention according to <6>, there is provided an electrostatic charge image developing toner having toner particles and silica particles externally added to the toner particles and containing a nitrogen element-containing compound, wherein when the pore volumes of pores having a pore diameter of 1 nm or more and 50 nm or less obtained from the pore distribution curve of the nitrogen gas adsorption method before and after firing at 350 ° C. are A and B, respectively, for the silica particles, B / A is less than 1.2, or B is less than 0.2 cm 3Compared to cases where the silica particles are less than / g, the toner for electrostatic image development is provided in which the silica particles contain at least one selected from the group consisting of quaternary ammonium salts, primary amine compounds, secondary amine compounds, tertiary amine compounds, amide compounds, imine compounds, and nitrile compounds, thereby suppressing fogging that occurs when repeatedly forming images.

[0015] <7> , or <8> According to the invention, a toner for developing electrostatic images comprises toner particles and silica particles containing a nitrogen-containing compound, wherein when the silica particles have pore volumes of 1 nm to 50 nm in diameter, determined from the pore distribution curve of the nitrogen gas adsorption method before and after firing at 350°C, A and B respectively, B / A is less than 1.2, or B is 0.2 cm³. 3 Compared to cases where silica particles are less than / g, a toner for developing electrostatic images is provided that suppresses fogging that occurs when repeatedly forming images, even when the average circularity of the silica particles is 0.60 to 0.96 or 0.70 to 0.92.

[0016] <9> According to the invention, the volume resistivity is 1.0 × 10 11.5 Compared to cases where the charge exceeds Ωcm, silica particles with a narrower charge distribution when charged are provided. <10> According to the invention, when the volume resistivity of silica particles before and after firing at 350°C is Ra and Rb, respectively, a toner for developing electrostatic images is provided that suppresses fogging that occurs when repeatedly forming images compared to when Ra / Rb is less than 0.01.

[0017] <11> According to the invention relating to this invention, the cross-polarization / magic angle rotation (CP / MAS) method for silica particles 29 Chemical shift of -50 ppm in Si solid-state nuclear magnetic resonance (NMR) spectrum from -75pp m The integral value C of the signal observed within the range, and the chemical shift of -90 ppm. from -120pp mA toner for developing electrostatic images is provided that suppresses fogging that occurs when repeatedly forming images, compared to cases where the ratio C / D of the integral value D of the signals observed in the range is less than 0.10 or greater than 0.75.

[0018] <12> According to the invention, a toner for developing electrostatic images comprises toner particles and silica particles containing a nitrogen-containing compound, wherein when the silica particles have pore volumes of 1 nm to 50 nm in diameter, determined from the pore distribution curve of the nitrogen gas adsorption method before and after firing at 350°C, A and B respectively, B / A is less than 1.2, or B is 0.2 cm 3 Compared to silica particles with a value of less than / g, the toner for electrostatic image development is provided, which has silica particles comprising silica matrix particles and a structure that coats at least a portion of the surface of the silica matrix particles and is composed of reaction products of a trifunctional silane coupling agent, with a nitrogen element-containing compound adsorbed on at least a portion of the pores of the reaction products of the trifunctional silane coupling agent, thereby suppressing fogging that occurs when repeatedly forming images.

[0019] <13> , <14> , <15> , <16> , or <17> According to the invention, a toner for developing electrostatic images comprises toner particles and silica particles containing a nitrogen-containing compound, wherein when the silica particles have pore volumes of 1 nm to 50 nm in diameter, determined from the pore distribution curve of the nitrogen gas adsorption method before and after firing at 350°C, A and B respectively, B / A is less than 1.2, or B is 0.2 cm 3 Compared to using an electrostatic image developing toner containing silica particles of less than 1g, the present invention provides an electrostatic image developing agent, toner cartridge, process cartridge, image forming apparatus, or image forming method that suppresses fogging that occurs when repeatedly forming images. [Brief explanation of the drawing]

[0020] [Figure 1] This is a schematic diagram showing the image forming apparatus according to this embodiment. [Figure 2] This is a schematic diagram showing the process cartridge according to this embodiment. [Modes for carrying out the invention]

[0021] The present invention will be described in detail below, showing an example embodiment.

[0022] In numerical ranges described stepwise within this specification, the upper or lower limit of one numerical range may be replaced by the upper or lower limit of another numerical range described stepwise. Furthermore, in numerical ranges described in this disclosure, the upper or lower limit of that range may be replaced by the values ​​shown in the examples.

[0023] In this specification, each component may contain multiple types of the relevant substance. In this specification, when referring to the amount of each component in a composition, if there are multiple substances corresponding to each component in the composition, unless otherwise specified, it refers to the total amount of those multiple substances present in the composition.

[0024] In this specification, the properties of silica particles are measured after separation from the toner. There are no restrictions on the method of separating silica particles from the toner, but for example, the following separation process may be used to separate the silica particles from the toner and perform the measurements on the obtained silica particles. -Separation process- 2g of toner is dispersed in 50g of a 0.2% by mass aqueous solution of Triton X-100 (manufactured by Sigma-Aldrich). An ultrasonic homogenizer US-300T (manufactured by Nippon Seiki Seisakusho Co., Ltd.) is applied to the dispersion at 20°C and 85 WATT for 30 minutes or more. The dispersion is then centrifuged at high speed, and the supernatant is vacuum-dried at 80°C to obtain silica particles.

[0025] <Toner for developing electrostatic images> The electrostatic image developing toner (also simply referred to as "toner") according to this embodiment is Toner particles and Silica particles added to the toner particles, containing a nitrogen-containing compound, where A and B are the pore volumes of pores with diameters of 1 nm to 50 nm, determined from the pore distribution curve of the nitrogen gas adsorption method before and after firing at 350°C, respectively, B / A is 1.2 to 5, and B is 0.2 cm³. 3 / g or more 3cm 3 Silica particles that are less than / g (hereinafter also referred to as "specific silica particles"), It holds.

[0026] Hereafter, "the pore volume A of pores with a diameter of 1 nm to 50 nm obtained from the pore distribution curve of the nitrogen gas adsorption method before firing at 350°C" will also be referred to as "the pore volume A before firing at 350°C". On the other hand, "the pore volume B of pores with a diameter of 1 nm to 50 nm, determined from the pore distribution curve of the nitrogen gas adsorption method after firing at 350°C" is also referred to as "the pore volume B after firing at 350°C".

[0027] The toner according to this embodiment, with the above configuration, suppresses fogging (i.e., the phenomenon of toner adhering to non-image areas) that occurs when repeatedly forming images. The reason for this is presumed to be as follows.

[0028] Silica particles have a high tendency to be negatively charged and can become excessively charged. This results in a wider charge distribution. Toner with silica particles that have a wide charge distribution can cause fogging and lead to contamination inside the machine.

[0029] On the other hand, adsorbing nitrogen-containing compounds onto silica particles can suppress excessive negative charge when the silica particles become charged. Nitrogen-containing compounds have positive charge properties, and silica particles on which nitrogen-containing compounds have been adsorbed cancel out excessive negative charge, thereby suppressing excessive negative charge.

[0030] However, nitrogen-containing compounds are positively charged, and when adsorbed onto the outermost surface of silica particles, the charge distribution spreads to include both negative and positive charges. Therefore, it is preferable for nitrogen-containing compounds to be present in pores or other structures rather than coating the surface of the silica particles.

[0031] Therefore, in the toner according to this embodiment, specific silica particles having the above-described relationship between the pore volume A before firing at 350°C and the pore volume B after firing at 350°C are used as an external additive. The pore volume B after firing at 350°C is the pore volume after the nitrogen-containing compound that was adsorbed into the pores of the silica particles and partially blocked them has evaporated. Therefore, B / A is between 1.2 and 5, and B is 0.2 cm³. 3 / g or more 3cm 3 A value of less than / g indicates that a sufficient amount of nitrogen-containing compound is adsorbed in at least some of the pores of the silica particles. Therefore, it suppresses the broadening of the charge distribution due to the nitrogen-containing compound.

[0032] From the above, it is presumed that the toner according to this embodiment suppresses the occurrence of fogging that occurs when repeatedly forming images.

[0033] Furthermore, the toner according to this embodiment uses specific silica particles as an external additive to suppress the broadening of the charge distribution by nitrogen-containing compounds, thereby suppressing the occurrence of toner splatter (hereinafter also referred to as "cloud") and a decrease in fine line reproducibility.

[0034] In addition, in the toner according to this embodiment, as an external additive, a nitrogen-containing compound is used, and in specific silica particles in which a sufficient amount of the nitrogen-containing compound is adsorbed in at least some of the pores of the silica particles, the nitrogen-containing compound is less likely to detach from the specific silica particles over time (for example, when repeated images are formed). As a result, the occurrence of fogging, clouding, and deterioration of fine line reproducibility are suppressed over time.

[0035] In the toner according to this embodiment, the specific silica particles exhibit a chemical shift of -50 ppm in the 29Si solid-state nuclear magnetic resonance (NMR) spectrum (hereinafter also referred to as the "Si-CP / MAS NMR spectrum") obtained by the cross-polarization / magic angle rotation (CP / MAS) method. from -75pp mThe integral value C of the signal observed within the range, and the chemical shift of -90 ppm. from -120pp m It is preferable that the ratio C / D of the integral value D of the signal observed within the range is between 0.10 and 0.75.

[0036] Certain silica particles, by possessing an integrated signal value that satisfies the above range, tend to have a narrower charge distribution when charged. As a result, fouling is more easily suppressed. The reason for this is presumed to be as follows. Having an integrated signal value that satisfies the above range indicates that at least some of the silica particle surfaces have formed a low-density structure (e.g., an SiO2 / 3CH3 layer) composed of reaction products of a trifunctional silane coupling agent, on which a sufficient amount of nitrogen-containing compound is adsorbed. The structure composed of reaction products of the trifunctional silane coupling agent is low-density and has a pore shape that facilitates the adsorption of nitrogen-containing compound. Furthermore, by reducing the amount of OH groups that inhibit the adsorption of nitrogen-containing compounds to the above range, a sufficient amount of nitrogen-containing compounds can be more easily adsorbed onto the structure composed of the reaction products of the trifunctional silane coupling agent, thereby increasing the amount of adsorption. Therefore, the narrowing of the charge distribution by nitrogen-containing compounds is improved. As a result, the occurrence of fogging is more easily suppressed. Furthermore, clouding and fine line reproducibility are also more easily suppressed.

[0037] The toner according to this embodiment will be described in detail below.

[0038] The toner according to this embodiment comprises toner particles and an external additive.

[0039] (Toner particles) The toner particles contain a binder resin. The toner particles may also contain colorants, release agents, and other additives as needed.

[0040] -Binding resin- Examples of binder resins include vinyl resins consisting of monomers such as styrenes (e.g., styrene, parachlorostyrene, α-methylstyrene, etc.), (meth)acrylic acid esters (e.g., methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, etc.), ethylenically unsaturated nitriles (e.g., acrylonitrile, methacrylonitrile, etc.), vinyl ethers (e.g., vinyl methyl ether, vinyl isobutyl ether, etc.), vinyl ketones (vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone, etc.), and olefins (e.g., ethylene, propylene, butadiene, etc.), or copolymers of two or more of these monomers. Examples of binder resins include non-vinyl resins such as epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, and modified rosin; mixtures of these with the aforementioned vinyl resins; and graft polymers obtained by polymerizing vinyl monomers in the presence of these. These binding resins may be used individually or in combination of two or more types.

[0041] Polyester resin is preferred as the binder resin. Examples of polyester resins include well-known polyester resins.

[0042] Examples of polyester resins include condensation polymers of polycarboxylic acids and polyhydric alcohols. Commercially available polyester resins or synthesized polyester resins may be used.

[0043] Examples of polycarboxylic acids include aliphatic dicarboxylic acids (e.g., oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, alkenylsuccinic acid, adipic acid, sebacic acid, etc.), alicyclic dicarboxylic acids (e.g., cyclohexanedicarboxylic acid, etc.), aromatic dicarboxylic acids (e.g., terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, etc.), their anhydrides, or their lower alkyl esters (e.g., with 1 to 5 carbon atoms). Among these, aromatic dicarboxylic acids are preferred as polycarboxylic acids. Polycarboxylic acids may be used in combination with dicarboxylic acids, or with trivalent or higher carboxylic acids that have a cross-linked or branched structure. Examples of trivalent or higher carboxylic acids include trimellitic acid, pyromellitic acid, their anhydrides, or their lower alkyl esters (e.g., having 1 to 5 carbon atoms). Polycarboxylic acids may be used individually or in combination of two or more.

[0044] Examples of polyhydric alcohols include aliphatic diols (e.g., ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, etc.), alicyclic diols (e.g., cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, etc.), and aromatic diols (e.g., ethylene oxide adducts of bisphenol A, propylene oxide adducts of bisphenol A, etc.). Among these, aromatic diols and alicyclic diols are preferred as polyhydric alcohols, and aromatic diols are more preferred. As for the polyhydric alcohol, a trihydric or higher polyhydric alcohol with a cross-linked or branched structure may be used in combination with the diol. Examples of trihydric or higher polyhydric alcohols include glycerin, trimethylolpropane, and pentaerythritol. Polyhydric alcohols may be used individually or in combination of two or more types.

[0045] The glass transition temperature (Tg) of the polyester resin is preferably 50°C to 80°C, and more preferably 50°C to 65°C. The glass transition temperature is determined from the DSC curve obtained by differential scanning calorimetry (DSC), and more specifically, it is determined by the "extracorporeal glass transition onset temperature" described in the method for determining the glass transition temperature in JIS K 7121-1987 "Method for Measuring the Transition Temperature of Plastics".

[0046] The weight-average molecular weight (Mw) of the polyester resin is preferably 5,000 to 1,000,000, and more preferably 7,000 to 500,000. The number-average molecular weight (Mn) of the polyester resin is preferably between 2,000 and 100,000. The molecular weight distribution (Mw / Mn) of the polyester resin is preferably 1.5 to 100, and more preferably 2 to 60. The weight-average molecular weight and number-average molecular weight are measured by gel permeation chromatography (GPC). GPC molecular weight measurement is performed using a Tosoh GPC-HLC-8120GPC analyzer, a Tosoh TSKgel SuperHM-M (15cm) column, and THF solvent. The weight-average molecular weight and number-average molecular weight are calculated from these measurement results using a molecular weight calibration curve prepared with monodisperse polystyrene standard samples.

[0047] Polyester resins can be obtained by well-known manufacturing methods. Specifically, for example, they can be obtained by a method in which the polymerization temperature is set to 180°C or higher and 230°C or lower, and the reaction system is subjected to reduced pressure as needed, while removing water and alcohol generated during condensation. If the monomers of the raw materials do not dissolve or become miscible at the reaction temperature, a high-boiling point solvent may be added as a solubilizer to dissolve them. In this case, the polycondensation reaction should be carried out while distilling off the solubilizer. If there are monomers with poor miscibility in the copolymerization reaction, it is advisable to condense the poorly miscible monomers with the acid or alcohol to be polycondensed with them beforehand, and then polycondense them together with the main component.

[0048] The binder resin content is preferably 40% to 95% by mass, more preferably 50% to 90% by mass, and even more preferably 60% to 85% by mass, relative to the total toner particles.

[0049] -Coloring agent- Examples of colorants include carbon black, chrome yellow, Hansa yellow, benzidine yellow, surene yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, balkan orange, Watch Young red, permanent red, brilliant carmine 3B, brilliant carmine 6B, DuPont oil red, pyrazolone red, risole red, rhodamine B lake, lake red C, pigment red, rose bengal, aniline blue, and ultramarine. Examples include various pigments such as phosphorus blue, chalcioyl blue, methylene blue chloride, phthalocyanine blue, pigment blue, phthalocyanine green, and malachite green oxalate, as well as various dyes such as acridine, xanthene, azo, benzoquinone, azine, anthraquinone, thioindico, dioxazine, thiazine, azomethine, indico, phthalocyanine, aniline black, polymethine, triphenylmethane, diphenylmethane, and thiazole. Colorants may be used individually or in combination of two or more types.

[0050] The coloring agent may be a surface-treated coloring agent as needed, and may be used in combination with a dispersant. Furthermore, multiple types of coloring agents may be used in combination.

[0051] The colorant content is preferably 1% to 30% by mass, and more preferably 3% to 15% by mass, relative to the total toner particles.

[0052] -Release agent- Examples of release agents include hydrocarbon waxes; natural waxes such as carnauba wax, rice wax, and candelilla wax; synthetic or mineral / petroleum-based waxes such as montan wax; and ester waxes such as fatty acid esters and montanic acid esters. However, the release agents are not limited to these.

[0053] The melting temperature of the release agent is preferably 50°C to 110°C, and more preferably 60°C to 100°C. The melting temperature is determined from the DSC curve obtained by differential scanning calorimetry (DSC) using the "melting peak temperature" described in JIS K 7121-1987 "Method for determining the transition temperature of plastics".

[0054] The release agent content is preferably 1% to 20% by mass, and more preferably 5% to 15% by mass, relative to the total toner particles.

[0055] -Other additives- Other additives include well-known additives such as magnetic materials, charge control agents, and inorganic powders. These additives are included in the toner particles as internal additives.

[0056] -Characteristics of toner particles, etc.- The toner particles may be single-layer toner particles, or they may be toner particles with a so-called core-shell structure, consisting of a core (core particle) and a coating layer (shell layer) that covers the core. Here, the core-shell structure of the toner particles may consist of, for example, a core portion comprising a binder resin and, if necessary, other additives such as a colorant and a release agent, and a coating layer comprising a binder resin.

[0057] The volume-average particle size (D50v) of the toner particles is preferably 2 μm or more and 10 μm or less, and more preferably 4 μm or more and 8 μm or less.

[0058] The average particle size and particle size distribution indices of the toner particles are measured using the Coulter Multisizer II (manufactured by Beckman Coulter), and the electrolyte is measured using the ISOTON-II (manufactured by Beckman Coulter). For measurement, add 0.5 mg to 50 mg of the sample to be measured in 2 ml of a 5% aqueous solution of a surfactant (preferably sodium alkylbenzenesulfonate) as a dispersant. Add this to 100 ml to 150 ml of electrolyte. The electrolyte containing the suspended sample is dispersed in an ultrasonic disperser for 1 minute. The particle size distribution of particles with a diameter of 2 μm to 60 μm is then measured using a Coulter Multisizer II with an aperture diameter of 100 μm. The number of particles sampled is 50,000. Based on the measured particle size distribution, a cumulative distribution of volume and number is drawn for each divided particle size range (channel) from the smallest diameter side. The particle size at which the cumulative total reaches 16% is defined as the volume particle size D16v and the number particle size D16p, the particle size at which the cumulative total reaches 50% is defined as the volume average particle size D50v and the cumulative number average particle size D50p, and the particle size at which the cumulative total reaches 84% ​​is defined as the volume particle size D84v and the number particle size D84p. Using these, the volume particle size distribution index (GSDv) is (D84v / D16v) 1 / 2 The GSDp index is (D84p / D16p) 1 / 2 It is calculated as follows.

[0059] The average circularity of the toner particles is preferably 0.950 or more and 0.990 or less, and more preferably 0.957 or more and 0.980 or less.

[0060] The average circularity of toner particles is measured using a Sysmex FPIA-3000. This device employs a flow-type image analysis method to measure particles dispersed in water or other liquids. The aspirated particle suspension is guided to a flat sheath flow cell, where a flattened sample flow is formed by the sheath liquid. By irradiating this sample flow with strobe light, the particles passing through are captured as still images by a CCD (Charge Coupled Device) camera through an objective lens. The captured particle images are then processed using 2D image processing to calculate the circularity from the projected area and perimeter. For circularity, at least 4,000 individual images are analyzed, and the average circularity is determined through statistical processing. Formula: Circularity = Equivalent diameter / perimeter / Perimeter = [2 × (Aπ)] 1 / 2 ] / PM In the above equation, A represents the projected area and PM represents the perimeter. For measurement, HPF mode (high-resolution mode) will be used, and the dilution ratio will be 1.0x. Furthermore, for data analysis, the circularity analysis range will be set to 0.40 to 1.00 to remove measurement noise.

[0061] (External additive) The external additive contains specific silica particles. The specified silica particles contain a nitrogen-containing compound, and when the pore volume of pores with a diameter of 1 nm to 50 nm, determined from the pore distribution curve of the nitrogen gas adsorption method before and after firing at 350°C, is denoted as A and B respectively, B / A is between 1.2 and 5, and B is 0.2 cm³. 3 / g or more 3cm 3 It is less than / g.

[0062] -Pore volume- In specific silica particles, the ratio B / A of the pore volume B after firing at 350°C to the pore volume A before firing at 350°C is preferably 1.2 or more and 5 or less, but from the viewpoint of suppressing fogging, clouding, and deterioration of fine wire reproducibility due to the narrowing of the charge distribution of silica particles, a ratio of 1.4 or more and 3 or less is preferred, and a ratio of 1.4 or more and 2.5 or less is more preferred.

[0063] The pore volume B after firing at 350°C is 0.2 cm³.3 / g or more 3cm 3 Although it is less than / g, from the viewpoint of suppressing fogging, clouding, and degradation of fine line reproducibility due to the narrowing of the charge distribution of silica particles, 0.3cm 3 / g or more 1.8cm 3 Preferably less than / g, and 0.6cm 3 / g or more 1.5cm 3 Less than / g is preferable.

[0064] The 350°C firing process will be carried out as follows: Under a nitrogen environment, the silica particles to be measured are heated to 350°C at a heating rate of 10°C / min and held at 350°C for 3 hours. After that, they are cooled to room temperature (25°C) at a heating rate of 10°C / min.

[0065] Pore ​​volume is measured as follows: First, the silica particles to be measured are cooled to liquid nitrogen temperature (-196°C), nitrogen gas is introduced, and the amount of adsorption is determined by the constant volume method or gravimetric method. The pressure of the introduced nitrogen gas is gradually increased, and an adsorption isotherm is created by plotting the amount of nitrogen gas adsorbed at each equilibrium pressure. From this adsorption isotherm, a pore size distribution curve is obtained using the BJH method formula, with frequency on the vertical axis and pore diameter on the horizontal axis. Then, from the obtained pore size distribution curve, the cumulative pore volume distribution is determined, with volume on the vertical axis and pore diameter on the horizontal axis. From the obtained cumulative pore volume distribution, the pore volumes in the range of pore diameters from 1 nm to 50 nm are integrated, and this is defined as the "pore volume of pores with diameters from 1 nm to 50 nm".

[0066] -CP / MAS NMR spectrum- Chemical shift in Si-CP / MAS NMR spectrum: -50 ppm from -75pp m The integral value C of the signal observed within the range, and the chemical shift of -90 ppm. from -120pp mThe ratio C / D of the integral value D of the signals observed within the range is between 0.10 and 0.75, but from the viewpoint of suppressing fogging, clouding, and degradation of fine-line reproducibility due to the narrowing of the charge distribution of silica particles, a value of 0.12 to 0.45 is preferred, and a value of 0.15 to 0.40 is more preferred. From the viewpoint of narrowing the charge distribution of silica particles and suppressing fogging, the chemical shift is -50 ppm when the integral value of all signals in the Si-CP / MAS NMR spectrum is set to 100%. from -75pp m The signal ratio (the proportion of the integral value C of the signal observed within the range) is preferably 5% or more, and more preferably 7% or more. The upper limit of the proportion of the integral value C of the signal is, for example, 60% or less.

[0067] The Si-CP / MAS NMR spectrum is obtained by performing nuclear magnetic resonance spectroscopy under the following conditions. • Spectrometer: AVENCE300 (manufactured by Brunker) ·Resonance frequency: 59.6MHz • Measurement nucleus: 29 Si • Measurement method: CPMAS method (using Bruker standard pulse sequencer cp.av) • Waiting time: 4 seconds • Contact time: 8 milliseconds • Total number of times: 2048 • Measurement temperature: Room temperature (actual measured value 25℃) • Observation center frequency: -3975.72Hz • MAS rotation speed: 7.0mm-6kHz • Reference substance: Hexymethylcyclotrisiloxane

[0068] -The composition of silica particles- The specific silica particles contain nitrogen-containing compounds. Specifically, the specific silica particles include a silica matrix particle, in which at least a portion of the surface of the silica matrix particle is coated with a reaction product of a trifunctional silane coupling agent, and further, a nitrogen-containing compound is adsorbed on at least a portion of the reaction product. By forming this structure, the pore volume characteristics and Si-CP / MASNMR spectral characteristics can be controlled. In addition, the degree of hydrophobicity and the amount of OH groups, as described later, can also be controlled. Furthermore, in the case of specific silica particles, a hydrophobic treated structure may be provided on the surface of the structure described above.

[0069] -Silica matrix particles- Silica matrix particles are silica particles in which at least a portion of their surface is composed of reaction products of a trifunctional silane coupling agent, and a structure is formed in which a nitrogen-containing compound is adsorbed in at least a portion of the pores of the reaction products of the trifunctional silane coupling agent. Examples of silica matrix particles include dry silica particles and wet silica particles. Examples of dry silica particles include fumed silica, which is obtained by burning silane compounds, and deflagration silica, which is obtained by explosively burning metallic silicon powder. Examples of wet silica particles include wet silica particles obtained by the neutralization reaction of sodium silicate and mineral acid (sedimentation silica synthesized and aggregated under alkaline conditions, and gel silica particles synthesized and aggregated under acidic conditions), colloidal silica particles (silica sol particles) obtained by polymerizing acidic silicic acid in an alkaline state, and sol-gel silica particles obtained by the hydrolysis of organosilane compounds (e.g., alkoxysilanes). Among these, sol-gel silica particles are preferred as silica matrix particles from the viewpoint of suppressing fogging, clouding, and degradation of fine wire reproducibility by narrowing the charge distribution of silica particles.

[0070] -Reaction products of trifunctional silane coupling agents- The adsorption structure composed of the reaction products of the trifunctional silane coupling agent is low-density and highly affinity for nitrogen-containing compounds. As a result, nitrogen-containing compounds are easily adsorbed deep into the pores, leading to a high amount of adsorption (i.e., content) of nitrogen-containing compounds. The adhesion of positively charged nitrogen-containing compounds to the negatively charged silica surface creates an effect of canceling out excess negative charge. Furthermore, because the nitrogen-containing compounds are adsorbed not on the outermost surface of the silica particles but within the low-density structure, it prevents the charge distribution from becoming too broad due to excessive positive charge, and instead cancels out only the excess negative charge, further improving the narrowing of the charge distribution. Consequently, it becomes easier to suppress fogging, clouding, and the decrease in fine-line reproducibility by narrowing the charge distribution of silica particles.

[0071] The reaction product of a trifunctional silane coupling agent is, for example, in the following general formula (TA): R 2 Reaction product in which the OH group is substituted, R 2 Reaction products formed by polycondensation of two groups with OH groups substituted, R 2 Examples include reaction products resulting from polycondensation between a compound substituted with an OH group and the SiOH group of silica particles. Furthermore, the reaction products of trifunctional silane coupling agents are as follows: R 2 This includes reaction products that are substituted in whole or in part, and reaction products that are polycondensed in whole or in part.

[0072] Trifunctional silane coupling agents are non-nitrogen element-containing compounds that do not contain nitrogen (N). Specifically, examples of trifunctional silane coupling agents include those represented by the following general formula (TA). General formula (TA):R 1 -Si( R 2 )3

[0073] In the general formula (TA), R 1R represents a saturated or unsaturated aliphatic hydrocarbon group having 1 to 20 carbon atoms or an aromatic hydrocarbon group having 6 to 20 carbon atoms. 2 R represents a halogen atom or alkoxy group. 2 These can be the same group or different groups.

[0074] R 1 The aliphatic hydrocarbon group represented by may be linear, branched, or cyclic, but linear or branched is preferred. The number of carbon atoms in the aliphatic hydrocarbon group is preferably 1 to 20, more preferably 1 to 18, even more preferably 1 to 12, and even more preferably 1 to 10. The aliphatic hydrocarbon group may be saturated or unsaturated, but a saturated aliphatic hydrocarbon group is preferred, and an alkyl group is more preferred.

[0075] Examples of saturated aliphatic hydrocarbon groups include linear alkyl groups (methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, dodecyl group, hexadecyl group, eicosyl group, etc.), branched alkyl groups (isopropyl group, isobutyl group, isopentyl group, neopentyl group, 2-ethylhexyl group, tert-butyl group, tert-pentyl group, isopentadecyl group, etc.), and cyclic alkyl groups (cyclopropyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, tricyclodecyl group, norbornyl group, adamantyl group, etc.).

[0076] Examples of unsaturated aliphatic hydrocarbon groups include alkenyl groups (vinyl group (ethenyl group), 1-propenyl group, 2-propenyl group, 2-butenyl group, 1-butenyl group, 1-hexenyl group, 2-dodecenyl group, pentenyl group, etc.) and alkynyl groups (ethynyl group, 1-propynyl group, 2-propynyl group, 1-butynyl group, 3-hexynyl group, 2-dodecynyl group, etc.).

[0077] R 1The aromatic hydrocarbon group represented by preferably has 6 to 20 carbon atoms, more preferably 6 to 18 carbon atoms, even more preferably 6 to 12 carbon atoms, and even more preferably 6 to 10 carbon atoms.

[0078] Examples of aromatic hydrocarbon groups include phenylene groups, biphenylene groups, terphenylene groups, naphthalene groups, and anthracene groups.

[0079] R 2 Examples of halogen atoms represented include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms. Chlorine atoms, bromine atoms, or iodine atoms are preferred as halogen atoms.

[0080] R 2 Examples of alkoxy groups represented by include alkoxy groups having 1 to 10 carbon atoms (preferably 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms). Examples of alkoxy groups include methoxy groups, ethoxy groups, isopropoxy groups, t-butoxy groups, n-butoxy groups, n-hexyloxy groups, 2-ethylhexyloxy groups, and 3,5,5-trimethylhexyloxy groups. Alkoxy groups also include substituted alkoxy groups. Examples of substituents that can be substituted for alkoxy groups include halogen atoms, hydroxyl groups, amino groups, alkoxy groups, amide groups, and carbonyl groups.

[0081] The trifunctional silane coupling agent represented by the general formula (TA) is R 1 is a saturated aliphatic hydrocarbon group having 1 to 20 carbon atoms, and R 2 A trifunctional silane coupling agent in which is a halogen atom or an alkoxy group is preferred.

[0082] Examples of trifunctional silane coupling agents include, Vinyltrimethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, butyltrimethoxysilane, hexyltrimethoxysilane, n-octyltrimethoxysilane, decyltrimethoxysilane, dodecyltrimethoxysilane, vinyltriethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, butyltriethoxysilane, hexyltriethoxysilane, decyltriethoxysilane, dodecyltriethoxysilane, phenyltrimethoxysilane, o-methylphenyltrimethoxysilane, p-methylphenyltrimethoxysilane, phenyltriethoxysilane, benzyltriethoxysilane, decyltrichlorosilane, phenyltrichlorosilane (all of the above, R 1 However, the compound is an unsubstituted aliphatic hydrocarbon group or an unsubstituted aromatic hydrocarbon group; 3-Glycidoxypropyltrimethoxysilane, γ-Methacryloxypropyltrimethoxysilane, γ-Mercaptopropyltrimethoxysilane, γ-Chloropropyltrimethoxysilane, γ-Glycidyloxypropylmethyldimethoxysilane (all of the above, R 1 However, it is a compound that has a substituted aliphatic hydrocarbon group or a substituted aromatic hydrocarbon group; These are some examples. The trifunctional silane coupling agent may be used alone or in combination of two or more types.

[0083] Among these, alkyltrialkoxysilanes are preferred as trifunctional silane coupling agents from the viewpoint of suppressing fogging, clouding, and degradation of fine line reproducibility by narrowing the charge distribution of silica particles, and in the general formula (TA), R 1 R represents an alkyl group having 1 to 20 carbon atoms (preferably 1 to 15 carbon atoms), 2 carbon number 1 or more and 2 or less Alkoxy group Alkyltrialkoxysilanes exhibiting the following properties are more preferred.

[0084] The amount of the structure composed of the reaction product of the trifunctional silane coupling agent attached is preferably 5.5% to 30% by mass relative to the silica particles, and more preferably 7% to 22% by mass, from the viewpoint of suppressing fogging, clouding, and reduction in fine line reproducibility due to narrowing of the charge distribution of silica particles.

[0085] -Nitrogen-containing compounds- Nitrogen-containing compounds are those containing nitrogen elements, excluding ammonia and compounds that are in a gaseous state at temperatures between -200°C and 25°C. It is preferable that the nitrogen-containing compound is adsorbed on at least a portion of the pores of the reaction product of the trifunctional silane coupling agent.

[0086] Examples of nitrogen-containing compounds include at least one selected from the group consisting of quaternary ammonium salts, primary amine compounds, secondary amine compounds, tertiary amine compounds, amide compounds, imine compounds, and nitrile compounds. Examples of primary amine compounds include phenethylamine, toluidine, catecholamine, and 2,4,6-trimethylaniline. Examples of secondary amine compounds include dibenzylamine, 2-nitrodiphenylamine, and 4-(2-octylamino)diphenylamine. Examples of tertiary amine compounds include 1,8-bis(dimethylamino)naphthalene, N,N-dibenzyl-2-aminoethanol, and N-benzyl-N-methylethanolamine. Examples of amide compounds include N-cyclohexyl-p-toluenesulfonamide, 4-acetamido-1-benzylpiperidine, and N-hydroxy-3-[1-(phenylthio)methyl-1H-1,2,3-triazole-4-yl]benzamide. Examples of imine compounds include diphenylmethaneimine, 2,3-bis(2,6-diisopropylphenylimino)butane, and N,N'-(ethane-1,2-diylidene)bis(2,4,6-trimethylaniline). Examples of nitrile compounds include 3-indoleacetonitrile, 4-[(4-chloro-2-pyrimidinyl)amino]benzonitrile, and 4-bromo-2,2-diphenylbutyronitrile.

[0087] Among these, quaternary ammonium salts are preferred as nitrogen-containing compounds from the viewpoint of suppressing fogging, clouding, and degradation of fine line reproducibility by narrowing the charge distribution of silica particles. Quaternary ammonium salts may be used individually or in combination of two or more types. The quaternary ammonium salt is not particularly limited, and any known quaternary ammonium salt can be used.

[0088] The quaternary ammonium salt preferably contains a compound represented by general formula (AM) from the viewpoint of suppressing fogging, clouding, and degradation of fine line reproducibility by narrowing the charge distribution of silica particles. The compound represented by general formula (AM) may be used alone or in combination of two or more types.

[0089] [ka] In the general formula (AM), R 1 , R 2 , R 3 and R 4 Each independently represents a hydrogen atom, or an alkyl group, aralkyl group, or aryl group which may have substituents, and X - R represents an anion. 1 , R 2 , R 3 and R 4 At least one of them represents an alkyl group, aralkyl group, or aryl group which may have substituents. Also, R 1 , R 2 , R 3 and R 4 Two or more of these may be linked together to form an aliphatic ring, an aromatic ring, or a heterocycle.

[0090] R 1 ~R4 Examples of alkyl groups represented by this formula include linear alkyl groups having 1 to 20 carbon atoms and branched alkyl groups having 3 to 20 carbon atoms. Examples of linear alkyl groups having 1 to 20 carbon atoms include methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, and n-hexadecyl group. Examples of branched alkyl groups having 3 to 20 carbon atoms include isopropyl group, isobutyl group, sec-butyl group, tert-butyl group, isopentyl group, neopentyl group, tert-pentyl group, isohexyl group, sec-hexyl group, tert-hexyl group, isoheptyl group, sec-heptyl group, tert-heptyl group, isooctyl group, sec-octyl group, tert-octyl group, isononyl group, sec-nonyl group, tert-nonyl group, isodecyl group, sec-decyl group, and tert-decyl group. Among the above, R 1 ~R 4 The alkyl group represented is preferably an alkyl group having 1 to 15 carbon atoms, such as a methyl group, ethyl group, butyl group, or tetradecyl group.

[0091] R 1 ~R 4 Examples of aralkyl groups represented by this symbol include aralkyl groups having 7 to 30 carbon atoms. Examples of aralkyl groups having 7 to 30 carbon atoms include benzyl group, phenylethyl group, phenylpropyl group, 4-phenylbutyl group, phenylpentyl group, phenylhexyl group, phenylheptyl group, phenyloctyl group, phenylnonyl group, naphthylmethyl group, naphthylethyl group, anthratilmethyl group, and phenylcyclopentylmethyl group. Among the above, R 1 ~R 4The aralkyl group represented by is preferably an aralkyl group having 7 to 15 carbon atoms such as benzyl group, phenylethyl group, phenylpropyl group, 4-phenylbutyl group and the like.

[0092] R 1 ~R 4 Examples of the aryl group represented by include aryl groups having 6 to 20 carbon atoms. Examples of the aryl group having 6 to 20 carbon atoms include phenyl group, pyridyl group, naphthyl group and the like. Among the above, the aryl group represented by R 1 ~R 4 is preferably an aryl group having 6 to 10 carbon atoms such as phenyl group.

[0093] X - Examples of the anion represented by include organic anions and inorganic anions. Examples of the organic anion include polyfluoroalkyl sulfonate ion, polyfluoroalkyl carboxylate ion, tetraphenylborate ion, aromatic carboxylate ion, aromatic sulfonate ion (such as 1-naphthol-4-sulfonate ion) and the like. Examples of the inorganic anion include molybdate ion (MoO4 2- , Mo2O7 2- , Mo3O 10 2- , Mo4O 13 2- , Mo7O 24 2- , Mo8O 26 4- etc.), OH - , F - , Fe(CN)6 3- , Cl - , Br - , NO2 - , NO3 - , CO3 2- , PO4 3- , SO4 2- etc.

[0094] In the general formula (AM), R 1 , R2 , R 3 and R 4 Two or more of these may be linked to each other to form a ring. 1 , R 2 , R 3 and R 4 Examples of rings formed by the linkage of two or more of these elements include alicyclic compounds with 2 to 20 carbon atoms and heterocyclic amines with 2 to 20 carbon atoms.

[0095] In compounds represented by the general formula (AM), R 1 , R 2 , R 3 and R 4 However, each group may independently have substituents. Examples of substituents include nitrile groups, carbonyl groups, ether groups, amide groups, siloxane groups, silyl groups, silanealkoxy groups, and the like. R 1 , R 2 , R 3 and R 4 Preferably, each of these independently represents an alkyl group having 1 to 16 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms.

[0096] Among these, from the viewpoint of suppressing fogging, clouding, and degradation of fine line reproducibility by narrowing the charge distribution of silica particles, the compound represented by general formula (AM) preferably has a total number of carbon atoms of 18 to 35, and more preferably 20 to 32.

[0097] X in compounds represented by general formula (AM) - Examples of other structures are shown below, but this embodiment is not limited thereto.

[0098] [ka]

[0099] The nitrogen-containing compound is preferably a nitrogen-containing compound containing molybdenum, from the viewpoint of suppressing fogging, clouding, and degradation of fine line reproducibility by narrowing the charge distribution of silica particles. It is preferably at least one selected from the group consisting of a quaternary ammonium salt containing molybdenum (particularly a salt of quaternary ammonium containing molybdenum) and a mixture of a quaternary ammonium salt and a metal oxide containing molybdenum. When a nitrogen compound contains molybdenum, it enhances the activity of the nitrogen element, allowing the nitrogen element to exhibit a moderate positive charge even when the nitrogen-containing compound is located inside the pores of silica particles rather than on the outermost surface. Therefore, when charged, the charge distribution becomes narrower, and the maintenance of the charge distribution is more easily achieved. As a result, clouding, fogging, and the reduction in fine-line reproducibility are more easily achieved. In particular, salts of quaternary ammonium containing molybdenum exhibit enhanced charge distribution maintenance because the molybdenum-containing anion (anion) strongly bonds with the quaternary ammonium cation (cation). As a result, fogging suppression, cloud suppression, and reduction in fine line reproducibility are more easily achieved.

[0100] Examples of quaternary ammonium salts containing molybdenum include: N( CH3)2(C 14 C H 29 )2]4Mo8O 26 [ N( C4H9)2(C6H5)2]2Mo2O7, N( CH3)2(CH2C6H5)(CH2) 17 CH3]2MoO4, [ N( CH3)2(CH2C6H5)(CH2) 15 Examples include CH3]2MoO4. Examples of metal oxides containing the element molybdenum include molybdenum oxide (molybdenum trioxide, molybdenum dioxide, Mo8O 26), alkali metal molybdate salts (lithium molybdate, sodium molybdate, potassium molybdate, etc.), alkaline earth metal molybdenum salts (magnesium molybdate, calcium molybdate, etc.), and other complex oxides Bi2O3·2MoO3, γ-Ce2Mo3O 13 Examples include:

[0101] -Detection and content of nitrogen-containing compounds- When certain silica particles are heated in a temperature range of 300°C to 600°C, nitrogen-containing compounds are detected. Specifically, for example, these include the following: For the detection of nitrogen-containing compounds, for example, a fall-feed pyrolysis gas chromatograph-mass spectrometer of the heating furnace type using He as a carrier gas can be used. Nitrogen-containing compounds can be detected under pyrolysis temperature conditions of 300°C to 600°C under inert gas conditions. Specifically, silica particles of 0.1 mg to 10 mg can be introduced into a pyrolysis gas chromatograph-mass spectrometer, and the presence or absence of nitrogen-containing compounds can be confirmed from the MS spectrum of the detected peaks. Examples of components produced by pyrolysis from silica particles containing nitrogen-containing compounds include primary to tertiary amines or aromatic nitrogen compounds represented by the following general formula (N). In the following general formula (N), R N1 ~R N3 Each independently represents a hydrogen atom, or an alkyl group, aralkyl group, or aryl group which may have substituents, and R N1 ~R N3 R is the general formula (AM) 1 , R 2 , and R 3 It is synonymous with [the above]. For example, if the nitrogen-containing compound is a quaternary ammonium salt, a portion of the side chain is removed by thermal decomposition at 600°C and detected as a tertiary amine. [ka]

[0102] From the viewpoint of suppressing fogging, clouding, and degradation of fine line reproducibility due to narrowing the charge distribution of silica particles, the nitrogen element-containing compound content is preferably 0.008% to 0.45% by mass, more preferably 0.015% to 0.20% by mass, and even more preferably 0.018% to 0.10% by mass, relative to the silica particles, in terms of N atoms.

[0103] The nitrogen content of nitrogen-containing compounds, calculated on a nitrogen atom basis, is measured as follows: Using an oxygen / nitrogen analyzer (e.g., EMGA-920 manufactured by Horiba, Ltd.), the amount of nitrogen is measured with an integration time of 45 seconds to obtain the ratio of N to Si. As a sample pretreatment, impurities such as ammonia are removed from the silica particles by drying them in a vacuum dryer at 100°C for 24 hours or more.

[0104] Here, when a nitrogen-containing compound containing molybdenum is applied as the nitrogen-containing compound, from the viewpoint of suppressing fogging, clouding, and degradation of fine-line reproducibility due to narrowing of the charge distribution of silica particles, the ratio of the net intensity of molybdenum to the net intensity of silicon (Mo / Si), measured by X-ray fluorescence analysis, is preferably 0.035 or more and 0.35 or less, preferably 0.07 or more and 0.32 or less, and more preferably 0.10 or more and 0.30 or less.

[0105] From the viewpoint of suppressing fogging, clouding, and degradation of fine-line reproducibility due to narrowing the charge distribution of silica particles, the Net strength of the molybdenum element is preferably 5 kcps to 75 kcps, 7 kcps to 50 kcps, 8 kcps to 55 kcps, or 10 kcps to 40 kcps.

[0106] The net strength of molybdenum and silicon elements is measured as follows:

[0107] Approximately 0.5 g of silica particles are compressed using a compression molding machine under a load of 6 tons for 60 seconds to produce a disk with a diameter of 50 mm and a thickness of 2 mm. This disk is used as a sample, and qualitative and quantitative elemental analysis is performed using a scanning X-ray fluorescence analyzer (XRF-1500, manufactured by Shimadzu Corporation) under the following conditions to determine the net intensity (unit: kilo counts per second, kcps) of molybdenum and silicon. • Tube voltage: 40kV ·Tube current: 90mA ·Measurement area (analysis diameter): Diameter 10mmφ • Measurement time: 30 minutes • Anti-cathode: Rhodium

[0108] - Extraction amount of nitrogen-containing compounds - The amount X extracted from nitrogen-containing compounds using an ammonia / methanol mixed solution should be 0.1% by mass or more, and the amount X extracted from nitrogen-containing compounds and the amount Y extracted from nitrogen-containing compounds using water should satisfy the formula: Y / X < 0.3.

[0109] In other words, nitrogen-containing compounds are poorly soluble in water, meaning they do not readily absorb moisture from the air. In silica particles containing a nitrogen-containing compound, when the nitrogen-containing compound adsorbs moisture, the charge distribution broadens, and the nitrogen-containing compound becomes more easily detached from the silica particles. However, silica particles containing nitrogen-containing compounds that do not readily adsorb moisture from the air maintain a narrow charge distribution even when there is a large amount of moisture in the air (under high humidity conditions). Furthermore, the nitrogen-containing compounds do not easily detach, making it easier to maintain a narrow charge distribution. As a result, it becomes easier to suppress fogging, clouding, and the decline in fine line reproducibility by narrowing the charge distribution of silica particles.

[0110] The extraction amount X of nitrogen-containing compounds is preferably 50% by mass or more. However, the upper limit of the extraction amount X of nitrogen-containing compounds is, for example, 95% by mass or less, because due to surface tension, the solution does not easily penetrate into the pores, and some of the nitrogen-containing compounds remain undissolved. The ratio "Y / X" of the amount of nitrogen-containing compound extracted X to the amount of nitrogen-containing compound extracted Y is preferably less than 0.3, and more preferably 0.15 or less. However, the lower limit of the ratio "Y / X" is ideally 0, but since the measurement error range of X and Y is approximately ±1%, it is, for example, 0.01 or more.

[0111] Here, the extraction amounts X and Y of the nitrogen-containing compound are measured as follows. First, the silica particles to be measured are analyzed at a constant temperature of 400°C using a thermogravimetric-mass spectrometer (for example, a gas chromatograph-mass spectrometer manufactured by Netch Japan Co., Ltd.). The integrated mass fraction of compounds in which at least one hydrocarbon is covalently bonded to a nitrogen atom is measured relative to the silica particles and defined as W1.

[0112] On the other hand, 1 part by mass of silica particles to be measured is added to 30 parts by mass of an ammonia / methanol solution (manufactured by Sigma-Aldrich, ammonia / methanol mass ratio = 1 / 5.2) at a liquid temperature of 25°C, and after sonication for 30 minutes, the silica powder and extract are separated. The separated silica particles are dried in a vacuum dryer at 100°C for 24 hours, and the mass fraction of compounds in which at least one hydrocarbon with a nitrogen atom is covalently bonded to the silica particles is measured using a thermogravimetric-mass spectrometer under constant conditions of 400°C, and this is defined as W2. Then, the amount X extracted from the nitrogen-containing compound is calculated using the following formula. ·Formula:X=W1-W2

[0113] Furthermore, 1 part by mass of silica particles to be measured is added to 30 parts by mass of water at a liquid temperature of 25°C, and sonication is performed for 30 minutes, after which the silica particles and extract are separated. The separated silica particles are dried in a vacuum dryer at 100°C for 24 hours, and the mass fraction of compounds in which at least one hydrocarbon with nitrogen atoms is covalently bonded to a nitrogen atom is measured relative to the silica particles using a thermogravimetric-mass spectrometer under constant conditions of 400°C, and this is defined as W3. Then, the amount Y extracted from the nitrogen-containing compound is calculated using the following formula. ·Formula: Y=W1-W3

[0114] (Hydrophobic treated structure) A hydrophobic treated structure is a structure that has reacted with a hydrophobic treatment agent. For example, organosilicon compounds can be used as hydrophobic treatment agents. Examples of organosilicon compounds include, Alkoxysilane compounds or halosilane compounds having a lower alkyl group such as methyltrimethoxysilane, dimethyldimethoxysilane, trimethylchlorosilane, or trimethylmethoxysilane; Alkoxysilane compounds having a vinyl group, such as vinyltrimethoxysilane and vinyltriethoxysilane; Alkoxysilane compounds having epoxy groups, such as 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropyltriethoxysilane; Alkoxysilane compounds having a styryl group, such as p-styryltrimethoxysilane and p-styryltriethoxysilane; Alkoxysilane compounds having aminoalkyl groups, such as N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, and N-phenyl-3-aminopropyltrimethoxysilane; Alkoxysilane compounds having an isocyanate alkyl group, such as 3-isocyanate-propyltrimethoxysilane and 3-isocyanate-propyltriethoxysilane; Silazane compounds such as hexamethyldisilazane and tetramethyldisilazane; These are some examples.

[0115] (Properties of silica particles) - Degree of hydrophobicity - The degree of hydrophobicity of the specific silica particles is preferably 10% to 60%, more preferably 20% to 55%, and even more preferably 28% to 53%, from the viewpoint of suppressing fogging, clouding, and degradation of fine line reproducibility by narrowing the charge distribution of the silica particles. When the degree of hydrophobicity of silica particles is 10% or less, the amount of structural coverage in the reaction product of the trifunctional silane coupling agent is low, and the content of nitrogen-containing compounds is reduced, which in turn makes it easier for the charge distribution to spread. On the other hand, when the degree of hydrophobicity of silica particles exceeds 60%, the density of the structure increases due to the reaction formation of the trifunctional silane coupling agent, resulting in fewer pores and a reduced content of nitrogen-containing compounds. As a result, the charge distribution tends to broaden. Consequently, it becomes easier to suppress fogging, clouding, and the decrease in fine-line reproducibility by narrowing the charge distribution of silica particles.

[0116] The degree of hydrophobicity of silica particles is measured as follows: 0.2% by mass of silica particles, which will be used as the sample, is added to 50 ml of deionized water. Methanol is added dropwise from a burette while stirring with a magnetic stirrer, and the mass fraction of methanol in the methanol-water mixture at the endpoint where the entire sample has settled is determined as the degree of hydrophobicity.

[0117] - Number-average particle size and number-particle size distribution index - The number-average particle size of the specific silica particles is preferably 10 nm to 200 nm, more preferably 10 nm to 80 nm, and even more preferably 10 nm to 60 nm. When the number-average particle size of silica particles is within the above range, the specific surface area is large and excessive charging is likely to occur. However, even when the number-average particle size of specific silica particles is within the above range, a narrowing of the charge distribution is achieved. As a result, even when the number-average particle size of specific silica particles is within the above range, it becomes easier to suppress fogging, clouding, and the decrease in fine-line reproducibility due to the narrowing of the charge distribution of silica particles.

[0118] The particle size distribution index for specific silica particles is preferably 1.1 or higher and 2.0 or lower, and more preferably 1.15 or higher and 1.6 or lower. When the particle size distribution index of specific silica particles falls within the above range, there are fewer coarse particles that tend to have a high charge and fewer fine particles that tend to have a low charge, making it easier to achieve a narrower charge distribution. As a result, it becomes easier to suppress fogging, clouding, and the decrease in fine wire reproducibility by narrowing the charge distribution of silica particles.

[0119] Here, the number-average particle size and number-size distribution index of silica particles are measured as follows. Silica particles are observed at 40,000x magnification using a scanning electron microscope (SEM). The images of the observed silica particles are analyzed using the image processing software WinRoof (manufactured by Mitani Corporation) to determine the equivalent circular diameter of at least 200 particles. Then, a cumulative distribution of the number of individual particles is plotted from the smallest diameter side, and the particle size and number-average particle diameter at which the cumulative distribution from the smallest diameter side reaches 50% are determined. Furthermore, starting from the smallest diameter, the square root of the value obtained by dividing the particle size D84, which accounts for 84% of the cumulative total, by the particle size D16, which accounts for 16% of the cumulative total, is defined as the "GSD (Grain Size Distribution Index)". That is, GSD = (D84 / D16) 0.5 That is the case.

[0120] -Circularity- The average circularity of the specific silica particles is preferably 0.60 to 0.96, more preferably 0.70 to 0.92, and even more preferably 0.75 to 0.90. When the average circularity of silica particles is within the above range, the specific surface area is large, and excessive charging is likely to occur. However, even when the average circularity of specific silica particles is within the above range, a narrowing of the charge distribution can be achieved. As a result, even when the average circularity of specific silica particles is within the above range, it becomes easier to suppress fogging, clouding, and the decrease in fine-line reproducibility due to the narrowing of the charge distribution of silica particles.

[0121] Here, the circularity of the silica particles is measured as follows: Silica particles are observed at 40,000x magnification using a scanning electron microscope (SEM). The images of the observed silica particles are analyzed using the image processing software WinRoof (manufactured by Mitani Corporation). The circularity of at least 200 particles is determined, and the average circularity is calculated by taking the arithmetic mean. The circularity is calculated using the following formula. Roundness = Equivalent diameter / perimeter / Perimeter = [2 × (Aπ)] 1 / 2 ] / PM In the above equation, A represents the projected area and PM represents the perimeter.

[0122] -Volume resistivity- The volume resistivity of specific silica particles (i.e., the volume resistivity before firing at 350°C) is 1.0 × 10⁻⁶. 7 Ωcm or greater: 1.0 × 10 11.5 Preferably less than Ωcm, and 1.0 × 10 8 Ωcm or greater: 1.0 × 10 11 A value of Ωcm or less is more preferable. When the volume resistivity of specific silica particles falls within the above range, the nitrogen-containing compound content is high, making excessive charging less likely and facilitating a narrower charge distribution. As a result, it becomes easier to suppress fogging, clouding, and the decline in fine-line reproducibility by narrowing the charge distribution of silica particles.

[0123] In specific silica particles, when the volume resistivity of the silica particles before and after firing at 350°C is denoted as Ra and Rb, respectively, Ra / Rb is preferably 0.01 to 0.8, and more preferably 0.015 to 0.6. When Ra / Rb is within the above range, the nitrogen-containing compound content is high, making it less likely for excessive charging to occur and easier to achieve a narrower charge distribution. As a result, it becomes easier to suppress fogging, clouding, and the decrease in fine-line reproducibility by narrowing the charge distribution of silica particles.

[0124] The 350°C firing will be carried out as described above. On the other hand, volume resistivity is measured as follows. The measurement environment is set to a temperature of 20°C and a humidity of 50% RH. 20cm 2 On the surface of a circular jig on which electrode plates are arranged, silica particles to be measured are placed to a thickness of approximately 1 mm to 3 mm to form a silica particle layer. On top of this, the same 20 cm as above is used. 2An electrode plate is placed on top of the silica particle layer, sandwiching it between the plates. To eliminate the gaps between the silica particles, a pressure of 0.4 MPa is applied to the electrode plate placed on the silica particle layer, and then the thickness (cm) of the silica particle layer is measured. Both electrodes above and below the silica particle layer are connected to an impedance analyzer (Solartron Analytical I), with a frequency of 10 -3 Hz over 10 6 Measure frequencies below Hz and obtain a Nyquist plot. Assuming the existence of three types of resistance components—bulk resistance, particle interface resistance, and electrode contact resistance—fit this plot to an equivalent circuit and determine the bulk resistance R. The formula for calculating the volume resistivity (Ω·cm) of silica particles is as shown below. ·Formula:ρ=R / L In the formula, ρ represents the volume resistivity of the silica particles (Ω·cm), R represents the bulk resistance (Ω), and L represents the thickness of the silica particle layer (cm).

[0125] (OH group amount) In specific silica particles, the amount of OH groups measured by the Sears method is 0.2 groups / nm. 2 More than 5.5 pieces / nm 2 The following is preferred, and from the viewpoint of suppressing fogging, clouding, and degradation of fine line reproducibility due to narrowing of the charge distribution of silica particles, 0.2 particles / nm 2 More than 4 pieces / nm 2 The following is more preferable: 0.2 particles / nm 2 More than 3 pieces / nm 2 The following are even more preferable. The amount of OH groups measured by the Sears method can be adjusted to the above range by sufficiently forming a structure composed of the reaction products of the trifunctional silane coupling agent in the silica matrix particles.

[0126] By reducing the amount of OH groups that inhibit the adsorption of nitrogen-containing compounds to the above range, nitrogen-containing compounds can more easily penetrate deep into the pores of silica particles (for example, the pores of the adsorption layer described later). Then, hydrophobic interactions with the nitrogen-containing compounds come into play, increasing their adhesion to the silica particles. As a result, the amount of nitrogen-containing compounds adsorbed increases. In addition, the nitrogen-containing compounds become less likely to detach. Therefore, the narrowing of the charge distribution by nitrogen-containing compounds is improved, as is the maintenance of the narrow charge distribution. As a result, it becomes easier to suppress fogging, clouding, and the decrease in fine-line reproducibility due to the narrowing of the charge distribution of silica particles.

[0127] Furthermore, by reducing the amount of OH groups to the above range, the environmental dependence of the charging characteristics is reduced, making it easier to narrow the charge distribution by nitrogen-containing compounds in any environment (especially in low-temperature, low-humidity environments where excessive negative charging is likely to occur). As a result, it becomes easier to suppress fogging, clouding, and the decrease in fine-line reproducibility by narrowing the charge distribution of silica particles.

[0128] The amount of OH groups is measured by the Sears method. Specifically, it is as follows: Add 1.5 g of silica particles to a mixture of 50 g of pure water and 50 g of ethanol, and stir in an ultrasonic homogenizer for 2 minutes to prepare a dispersion. While stirring at 25°C, add 1.0 g of 0.1 mol / L hydrochloric acid aqueous solution dropwise to obtain the test solution. Place the obtained test solution in an automatic titrator and perform potentiometric titration with 0.01 mol / L sodium hydroxide aqueous solution to create the differential curve of the titration curve. Among the inflection points where the differential value of the titration curve is 1.8 or greater, the titration volume at which the titration volume of 0.01 mol / L sodium hydroxide aqueous solution is greatest is defined as E. Using the following formula, the surface silanol group density ρ (groups / nm) of silica particles is calculated. 2 Calculate ). Formula: ρ=((0.01×E-0.1)×NA / 1000) / (M×S BET ×10 18 ) The details of the signs in the formula are as follows: E: The titration volume at which the titration volume of 0.01 mol / L sodium hydroxide solution is greatest, among the inflection points where the differential value of the titration curve is 1.8 or greater. NA: Avogadro's number M: Silica particle amount (1.5g) S BET Specific surface area of ​​silica particles (m²) 2 The specific surface area of ​​silica particles ( / g) is measured using the BET nitrogen adsorption method with three points. The equilibrium relative pressure is assumed to be 0.3.

[0129] -Method for manufacturing specific silica particles- An example of a method for producing specific silica particles is: A first step involves forming a structure on at least a portion of the surface of silica matrix particles, composed of the reaction product of a trifunctional silane coupling agent, A second step involves adsorbing a nitrogen-containing compound onto at least a portion of the pores of the reaction product of the trifunctional silane coupling agent, It has. A method for producing specific silica particles may further include a third step in which, after or during the second step, a hydrophobic treatment is performed on silica mother particles having a structure composed of reaction products of a trifunctional silane coupling agent, in which a nitrogen-containing compound is adsorbed on at least a portion of the pores of the reaction products of the trifunctional silane coupling agent.

[0130] The following describes in detail the manufacturing process of specific silica particles.

[0131] [Preparation process] First, let's explain the process of preparing the silica matrix particles.

[0132] Preparation steps include, for example, (i) A step of preparing a silica mother particle suspension by mixing a solvent containing alcohol with silica mother particles. (ii) A step of obtaining a silica mother particle suspension by granulating silica mother particles using the sol-gel method. These are some examples. Examples of silica matrix particles used in (i) above include sol-gel silica particles (silica particles obtained by the sol-gel method), aqueous colloidal silica particles, alcoholic silica particles, vaporized silica particles obtained by the gas phase method, and fused silica particles. The alcohol-containing solvent used in (i) above may be an alcohol-only solvent or a mixed solvent of alcohol and other solvents. Examples of alcohols include lower alcohols such as methanol, ethanol, n-propanol, isopropanol, and butanol. Examples of other solvents include water; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; cellosolves such as methyl cellosolve, ethyl cellosolve, butyl cellosolve, and acetate cellosolve; and ethers such as dioxane and tetrahydrofuran. In the case of a mixed solvent, the proportion of alcohol is preferably 80% by mass or more, and more preferably 85% by mass or more.

[0133] Step (1-a) is preferably a step of obtaining a silica mother particle suspension by granulating silica mother particles using a sol-gel method. More specifically, step (1-a) is, for example, The alkaline catalyst solution preparation step involves preparing an alkaline catalyst solution containing an alkaline catalyst in a solvent containing an alcohol, A silica matrix particle generation step involves supplying tetraalkoxysilane and an alkaline catalyst into an alkaline catalyst solution to generate silica matrix particles, A sol-gel method including this is preferable.

[0134] The alkaline catalyst solution preparation step preferably involves preparing a solvent containing alcohol, and mixing this solvent with the alkaline catalyst to obtain the alkaline catalyst solution.

[0135] The solvent containing alcohol may be a solvent of alcohol alone, or a mixed solvent of alcohol and other solvents. Examples of alcohols include lower alcohols such as methanol, ethanol, n-propanol, isopropanol, and butanol. Examples of other solvents include water; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; cellosolves such as methyl cellosolve, ethyl cellosolve, butyl cellosolve, and acetate cellosolve; and ethers such as dioxane and tetrahydrofuran. In the case of a mixed solvent, the proportion of alcohol is preferably 80% by mass or more, and more preferably 85% by mass or more.

[0136] Alkaline catalysts are catalysts used to accelerate the reactions (hydrolysis and condensation) of tetraalkoxysilanes. Examples of basic catalysts include ammonia, urea, and monoamines, with ammonia being particularly preferred.

[0137] The concentration of the alkaline catalyst in the alkaline catalyst solution is preferably 0.5 mol / L or more and 1.5 mol / L or less, more preferably 0.6 mol / L or more and 1.2 mol / L or less, and even more preferably 0.65 mol / L or more and 1.1 mol / L or less.

[0138] The silica mother particle generation process involves supplying tetraalkoxysilane and an alkaline catalyst to an alkaline catalyst solution, and then reacting the tetraalkoxysilane in the alkaline catalyst solution (hydrolysis and condensation reactions) to generate silica mother particles.

[0139] In the silica matrix particle generation process, nuclei are generated by the reaction of tetraalkoxysilane during the initial supply of tetraalkoxysilane (nuclei particle generation stage), and then silica matrix particles are generated through the growth of these nuclei (nuclei particle growth stage).

[0140] Examples of the tetraalkoxysilane include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, etc. From the viewpoint of the controllability of the reaction rate or the uniformity of the shape of the silica mother particles to be produced, tetramethoxysilane or tetraethoxysilane is preferred.

[0141] Examples of the alkali catalyst to be supplied into the alkali catalyst solution include basic catalysts such as ammonia, urea, monoamine, and quaternary ammonium salts, and ammonia is particularly preferred. The alkali catalyst supplied together with the tetraalkoxysilane may be of the same type as the alkali catalyst pre-contained in the alkali catalyst solution or of a different type, but it is preferably of the same type.

[0142] The supply method of supplying the tetraalkoxysilane and the alkali catalyst into the alkali catalyst solution may be a continuous supply method or an intermittent supply method.

[0143] In the silica mother particle production step, the temperature of the alkali catalyst solution (temperature at the time of supply) is preferably 5°C or higher and 50°C or lower, and more preferably 15°C or higher and 45°C or lower.

[0144] [First step] In the first step, a structure composed of the reaction product of a trifunctional silane coupling agent is formed. Specifically, in the first step, for example, a trifunctional silane coupling agent is added to the silica mother particle suspension, and the trifunctional silane coupling agent is reacted on the surface of the silica mother particles to form a structure composed of the reaction product of the trifunctional silane coupling agent. The trifunctional silane coupling agent reacts with the functional groups of the trifunctional silane coupling agent and the OH groups on the surface of the silica particles to form a structure composed of the reaction product of the trifunctional silane coupling agent.

[0145] The reaction of the trifunctional silane coupling agent is carried out by adding the trifunctional silane coupling agent to the silica mother particle suspension and then heating the suspension while stirring. Specifically, for example, the suspension is heated to 40 °C or higher and 70 °C or lower, the trifunctional silane coupling agent is added, and then stirring is carried out. The duration of continuous stirring is preferably 10 minutes or more and 24 hours or less, more preferably 60 minutes or more and 420 minutes or less, and even more preferably 80 minutes or more and 300 minutes or less.

[0146] [Second Step] In the second step, a nitrogen element-containing compound is adsorbed onto at least a part of the pores of the reaction product of the trifunctional silane coupling agent. Specifically, in the second step, first, for example, a nitrogen element-containing compound is added to the silica mother particle suspension, and stirring is carried out, for example, within a temperature range of 20 °C or higher and 50 °C or lower. Thereby, the nitrogen element-containing compound is adsorbed onto at least a part of the pores of the reaction product of the trifunctional silane coupling agent.

[0147] In the second step, for example, an alcohol solution containing a nitrogen element-containing compound may be added to the silica particle suspension. The alcohol may be of the same type as the alcohol contained in the silica mother particle suspension or of a different type, but it is more preferably of the same type.

[0148] In the alcohol solution containing the nitrogen element-containing compound, the concentration of the nitrogen element-containing compound is preferably 0.05% by mass or more and 10% by mass or less, and more preferably 0.1% by mass or more and 6% by mass or less.

[0149] [Third Step] In the third step, after or during the second step, a hydrophobic treatment is performed on the silica mother particles having a structure in which a nitrogen element-containing compound is adsorbed onto at least a part of the pores of the reaction product of the trifunctional silane coupling agent. Specifically, in the third step, for example, after adding a nitrogen element-containing compound to the silica mother particle suspension in which the structure is formed, a hydrophobic treatment agent is added. [[ID= 29]] The hydrophobic treatment agent forms a hydrophobic layer through reactions between the functional groups of the hydrophobic treatment agent and between the functional groups of the hydrophobic treatment agent and the OH groups of the silica matrix particles.

[0150] The reaction of the hydrophobic treatment agent is carried out by adding a trifunctional silane coupling agent to a suspension of silica matrix particles, and then heating the suspension while stirring. Specifically, for example, the suspension is heated to 40°C or 70°C, a hydrophobic treatment agent is added, and then the mixture is stirred. The duration of stirring is preferably 10 minutes to 24 hours, more preferably 20 minutes to 120 minutes, and even more preferably 20 minutes to 90 minutes.

[0151] [Drying process] A method for producing specific silica particles may involve a drying step to remove the solvent from the suspension after carrying out the second or third step. The drying step may also be carried out during the second or third step.

[0152] Drying methods include, for example, heat drying, spray drying, and supercritical drying. Spray drying can be performed using conventionally known methods with commercially available spray dryers (such as disc-rotating or nozzle-type dryers). For example, it can be performed by spraying the spray liquid into a hot air stream at a rate of 0.2 liters / hour to 1 liter / hour. In this case, the temperature of the hot air is preferably in the range of 70°C to 400°C at the inlet and 40°C to 120°C at the outlet. If the inlet temperature is below 70°C, the drying of the solid components in the dispersion will be insufficient. If it exceeds 400°C, the shape of the particles will be distorted during spray drying. If the outlet temperature is below 40°C, the degree of drying of the solid components will be poor and they will adhere to the inside of the device. A more preferable inlet temperature is in the range of 100°C to 300°C. The silica particle concentration of the silica particle suspension during spray drying is preferably in the range of 10% to 30% by mass in terms of solid content.

[0153] Supercritical drying removes the solvent using a supercritical fluid, which reduces surface tension between particles. As a result, primary particles in the suspension are dried in a state where aggregation is suppressed. Therefore, silica particles with high particle size uniformity are more easily obtained.

[0154] Substances that can be used as supercritical fluids include carbon dioxide, water, methanol, ethanol, and acetone. From the viewpoint of processing efficiency and suppression of the generation of coarse particles, the solvent removal step is preferably a step that uses supercritical carbon dioxide.

[0155] Supercritical drying is specifically carried out by the following procedure, for example: A suspension is placed in a sealed reactor, then liquefied carbon dioxide is introduced. The sealed reactor is then heated, and the pressure inside is increased using a high-pressure pump to bring the carbon dioxide inside the reactor to a supercritical state. Liquefied carbon dioxide is then introduced into the sealed reactor, and the supercritical carbon dioxide is released from the reactor, thereby circulating supercritical carbon dioxide through the suspension inside the reactor. As the supercritical carbon dioxide circulates through the suspension, the solvent dissolves in the supercritical carbon dioxide and is removed along with the supercritical carbon dioxide escaping from the sealed reactor. The temperature and pressure inside the sealed reactor described above are those that bring carbon dioxide to a supercritical state. Given that the critical point of carbon dioxide is 31.1°C / 7.38 MPa, for example, the temperature and pressure should be between 40°C and 200°C / 10 MPa and 30 MPa.

[0156] In supercritical drying, the flow rate of the supercritical fluid is preferably between 80 mL / second and 240 mL / second.

[0157] For the obtained specific silica particles, it is preferable to crush or sieve them as needed to remove coarse particles and agglomerates. Crushing can be performed using dry grinding equipment such as a jet mill, vibratory mill, ball mill, or pin mill. Sieving can be performed using, for example, a vibratory screen or an air-powered screen.

[0158] The external addition amount (content) of the specific silica particles is preferably, for example, 0.25% by mass or more and 2.0% by mass or less, more preferably 0.5% by mass or more and 1.5% by mass or less, based on the toner particles.

[0159] -Other external additives- The external additives may be used in combination with other external additives other than the specific silica particles. Examples of the other external additives include other inorganic particles and organic particles other than the specific silica particles. Examples of the other inorganic particles include particles such as silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, chromium oxide, cerium oxide, magnesium oxide, zirconium oxide, silicon carbide, and silicon nitride.

[0160] The surface of the other inorganic particles is preferably subjected to a hydrophobization treatment. The hydrophobization treatment is performed, for example, by immersing the inorganic particles in a hydrophobization treatment agent. The hydrophobization treatment agent is not particularly limited, and examples thereof include silane-based coupling agents, silicone oils, titanate-based coupling agents, and aluminum-based coupling agents. These may be used alone or in combination of two or more. The amount of the hydrophobization treatment agent is usually, for example, 1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the other inorganic particles.

[0161] Examples of the organic particles include resin particles (resin particles such as polystyrene, polymethyl methacrylate (PMMA), and melamine resin), cleaning agents (for example, metal salts of higher fatty acids typified by zinc stearate, and particles of fluorine-based high molecular weight substances), and the like.

[0162] The external addition amount (content) of the other external additives is preferably, for example, 0.05% by mass or more and 5.0% by mass or less, more preferably 0.5% by mass or more and 3.0% by mass or less, based on the toner particles.

[0163] (Method for producing toner) Next, a description of the toner manufacturing method according to this embodiment will be given. The toner according to this embodiment is obtained by manufacturing toner particles and then adding an external additive to the toner particles as needed.

[0164] Toner particles may be manufactured by either a dry process (e.g., kneading and grinding method) or a wet process (e.g., agglomeration, suspension polymerization, dissolution and suspension method). There are no particular restrictions on the manufacturing method of toner particles, and any well-known method may be used. Among these methods, obtaining toner particles by the aggregation and coalescence method is preferable.

[0165] Specifically, for example, when manufacturing toner particles by an aggregation and coalescence method, Toner particles are manufactured through the following steps: preparing a resin particle dispersion in which resin particles that will serve as a binder are dispersed (resin particle dispersion preparation step); a step of agglomerating resin particles (and other particles as needed) in the resin particle dispersion (and in a dispersion after mixing with other particle dispersions as needed) to form aggregated particles (aggregated particle formation step); and a step of heating the aggregated particle dispersion in which the aggregated particles are dispersed to fuse and combine the aggregated particles to form toner particles (fusion and combination step).

[0166] The details of each step are explained below. The following explanation describes a method for obtaining toner particles containing a colorant and a release agent, but the colorant and release agent are used only as needed. Of course, other additives besides colorants and release agents may also be used.

[0167] -Resin particle dispersion preparation process- First, a resin particle dispersion containing resin particles that will act as a binder is prepared, along with, for example, a coloring agent particle dispersion containing coloring agent particles and a release agent particle dispersion containing release agent particles.

[0168] Here, the resin particle dispersion is prepared, for example, by dispersing resin particles in a dispersion medium with a surfactant.

[0169] Examples of dispersion media used in resin particle dispersions include aqueous media. Examples of aqueous media include water such as distilled water and deionized water, and alcohols. These may be used individually or in combination of two or more.

[0170] Examples of surfactants include anionic surfactants such as sulfate esters, sulfonates, phosphates, and soaps; cationic surfactants such as amine salts and quaternary ammonium salts; and nonionic surfactants such as polyethylene glycol, alkylphenol ethylene oxide adducts, and polyhydric alcohols. Among these, anionic surfactants and cationic surfactants are particularly noteworthy. Nonionic surfactants may be used in combination with anionic or cationic surfactants. Surfactants may be used individually or in combination of two or more types.

[0171] In resin particle dispersions, common dispersion methods for dispersing resin particles in a dispersion medium include, for example, rotary shear homogenizers, ball mills with media, sand mills, and dyno mills. Depending on the type of resin particles, the resin particles may also be dispersed in the resin particle dispersion using, for example, a phase inversion emulsification method. Phase inversion emulsification is a method in which the resin to be dispersed is dissolved in a hydrophobic organic solvent in which the resin is soluble, a base is added to the organic continuous phase (O phase) to neutralize it, and then an aqueous medium (W phase) is added. This causes a conversion of the resin from W / O to O / W (so-called phase inversion), resulting in a discontinuous phase, and the resin is dispersed in the aqueous medium in particulate form.

[0172] The volume-average particle size of the resin particles dispersed in the resin particle dispersion is preferably 0.01 μm or more and 1 μm or less, more preferably 0.08 μm or more and 0.8 μm or less, and even more preferably 0.1 μm or more and 0.6 μm or less. The volume-average particle size of the resin particles is measured using a laser diffraction particle size distribution analyzer (e.g., LA-700, manufactured by Horiba, Ltd.). The particle size distribution is obtained by subtracting the cumulative distribution from the smallest particle size side for each divided particle size range (channel), and the particle size that accounts for 50% of the total particle size is measured as the volume-average particle size D50v. The volume-average particle size of particles in other dispersions is measured in the same manner.

[0173] The resin particle content in the resin particle dispersion is preferably, for example, 5% by mass or more and 50% by mass or less, and more preferably 10% by mass or more and 40% by mass or less.

[0174] Furthermore, colorant particle dispersions and release agent particle dispersions are prepared in the same manner as resin particle dispersions. In other words, the volume average particle size, dispersion medium, dispersion method, and particle content of the resin particle dispersions are the same for colorant particles dispersed in colorant particle dispersions and release agent particles dispersed in release agent particle dispersions.

[0175] -Agglomerated particle formation process- Next, the resin particle dispersion is mixed with the coloring agent particle dispersion and the mold release agent particle dispersion. Then, in the mixed dispersion, the resin particles, colorant particles, and release agent particles are heteroaggregated to form aggregated particles containing the resin particles, colorant particles, and release agent particles, which have a diameter close to the diameter of the target toner particles.

[0176] Specifically, for example, a coagulant is added to a mixed dispersion, the pH of the mixed dispersion is adjusted to be acidic (for example, pH 2 to 5), a dispersion stabilizer is added as needed, and then the mixture is heated to a temperature of the glass transition temperature of the resin particles (specifically, for example, above the glass transition temperature of the resin particles -30°C or below the glass transition temperature of -10°C) to agglomerate the particles dispersed in the mixed dispersion and form agglomerated particles. In the agglomerated particle formation step, for example, the mixed dispersion may be stirred in a rotary shear homogenizer, the above-mentioned flocculant may be added at room temperature (e.g., 25°C), the pH of the mixed dispersion may be adjusted to acidic (e.g., pH 2 to 5), a dispersion stabilizer may be added as needed, and then the above-mentioned heating may be performed.

[0177] Examples of flocculants include surfactants with opposite polarity to the surfactant used as a dispersant added to a mixed dispersion, inorganic metal salts, and metal complexes with a valency of 2 or higher. In particular, when a metal complex is used as a flocculant, the amount of surfactant used is reduced and the electrostatic properties are improved. Additives that form complexes or similar bonds with the metal ions of the flocculant may be used as needed. Chelating agents are preferably used as such additives.

[0178] Examples of inorganic metal salts include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate, as well as inorganic metal salt polymers such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. As a chelating agent, a water-soluble chelating agent may be used. Examples of chelating agents include oxycarboxylic acids such as tartaric acid, citric acid, and gluconic acid, as well as iminodic acid (IDA), nitrilotriacetic acid (NTA), and ethylenediaminetetraacetic acid (EDTA). The amount of chelating agent to be added is preferably 0.01 parts by mass or more and 5.0 parts by mass or less per 100 parts by mass of resin particles, and more preferably 0.1 parts by mass or more and less than 3.0 parts by mass.

[0179] -Fusion / coalescence process- Next, the dispersion of aggregated particles is heated to a temperature above the glass transition temperature of the resin particles (for example, 10 to 30°C higher than the glass transition temperature of the resin particles) to fuse and combine the aggregated particles and form toner particles.

[0180] Toner particles are obtained through the above process. Furthermore, toner particles may be manufactured by further mixing a dispersion of aggregated particles containing dispersed aggregated particles with a dispersion of resin particles containing dispersed resin particles, thereby agglomerating the aggregated particles so that resin particles adhere to the surface of the aggregated particles to form second aggregated particles, and by heating the second dispersion of aggregated particles containing the second aggregated particles to fuse and combine the second aggregated particles to form toner particles with a core / shell structure.

[0181] After the fusion and combination process is complete, the toner particles formed in the solution are subjected to known washing, solid-liquid separation, and drying processes to obtain dried toner particles. The washing process should be thoroughly performed using ion-exchanged water for displacement washing, considering the electrostatic charge. The solid-liquid separation process is not particularly restricted, but suction filtration, pressure filtration, etc., are preferable for productivity. The drying process is also not particularly restricted, but freeze-drying, air-flow drying, fluidized bed drying, vibratory fluidized bed drying, etc., are preferable for productivity.

[0182] The toner according to this embodiment is manufactured, for example, by adding an external additive to the obtained dried toner particles and mixing them. Mixing can be performed using, for example, a V-blender, a Henschel mixer, a Rödige mixer, etc. Furthermore, if necessary, coarse particles of the toner may be removed using a vibrating screen separator, a wind screen separator, etc.

[0183] <Electrostatic Image Developer> The electrostatic image developer according to this embodiment includes at least the toner according to this embodiment. The electrostatic image developer according to this embodiment may be a one-component developer containing only the toner according to this embodiment, or it may be a two-component developer mixed with the toner and a carrier.

[0184] There are no particular restrictions on the carriers, and known carriers can be used. Examples of carriers include coated carriers in which a coating resin is applied to the surface of a core material made of magnetic powder; magnetic powder dispersed carriers in which magnetic powder is dispersed and blended in a matrix resin; and resin-impregnated carriers in which resin is impregnated into porous magnetic powder. Furthermore, magnetic powder dispersed carriers and resin-impregnated carriers may be carriers in which the constituent particles of the carrier are used as a core material and coated with a coating resin.

[0185] Examples of magnetic powders include magnetic metals such as iron, nickel, and cobalt, and magnetic oxides such as ferrite and magnetite.

[0186] Examples of coating resins and matrix resins include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic acid ester copolymer, straight silicone resin or modified thereof containing organosiloxane bonds, fluororesin, polyester, polycarbonate, phenolic resin, epoxy resin, and the like. Furthermore, the coating resin and matrix resin may contain conductive particles or other additives. Examples of conductive particles include metals such as gold, silver, and copper, as well as carbon black, titanium oxide, zinc oxide, tin oxide, barium sulfate, aluminum borate, and potassium titanate.

[0187] To coat the surface of the core material with a coating resin, one method is to coat it with a coating layer-forming solution in which the coating resin and, if necessary, various additives are dissolved in a suitable solvent. The solvent is not particularly limited and should be selected considering the coating resin used, its suitability for coating, etc. Specific resin coating methods include the immersion method, in which the core material is immersed in a coating layer forming solution; the spray method, in which the coating layer forming solution is sprayed onto the surface of the core material; the fluidized bed method, in which the coating layer forming solution is sprayed onto the core material while it is suspended by fluidized air; and the kneader coater method, in which the carrier core material and the coating layer forming solution are mixed in a kneader coater and the solvent is removed.

[0188] In a two-component developer, the mixing ratio (mass ratio) of toner and carrier is preferably toner:carrier = 1:100 to 30:100, and more preferably 3:100 to 20:100.

[0189] <Image forming device / image forming method> An image forming apparatus / image forming method according to this embodiment will be described. The image forming apparatus according to this embodiment comprises an image holder, a charging means for charging the surface of the image holder, an electrostatic image forming means for forming an electrostatic image on the charged surface of the image holder, a developing means for containing an electrostatic image developer and developing the electrostatic image formed on the surface of the image holder as a toner image using the electrostatic image developer, a transfer means for transferring the toner image formed on the surface of the image holder to the surface of a recording medium, a cleaning means having a cleaning blade for cleaning the surface of the image holder, and a fixing means for fixing the toner image transferred to the surface of the recording medium. The electrostatic image developer according to this embodiment is applied as the electrostatic image developer.

[0190] The image forming apparatus according to this embodiment implements an image forming method (image forming method according to this embodiment) comprising: a charging step of charging the surface of an image holder; an electrostatic image forming step of forming an electrostatic image on the charged surface of an image holder; a developing step of developing the electrostatic image formed on the surface of an image holder as a toner image using an electrostatic image developer according to this embodiment; a transfer step of transferring the toner image formed on the surface of an image holder to the surface of a recording medium; a cleaning step of cleaning the surface of an image holder with a cleaning blade; and a fixing step of fixing the toner image transferred to the surface of a recording medium.

[0191] The image forming apparatus according to this embodiment may be a well-known image forming apparatus such as a direct transfer apparatus that directly transfers a toner image formed on the surface of an image holder to a recording medium; an intermediate transfer apparatus that first transfers a toner image formed on the surface of an image holder to the surface of an intermediate transfer body, and then secondarily transfers the toner image transferred to the surface of the intermediate transfer body to the surface of a recording medium; or an apparatus equipped with a static elimination means that irradiates the surface of the image holder with static elimination light to eliminate static charge after the transfer of the toner image and before charging. In the case of an intermediate transfer method apparatus, the transfer means may include, for example, an intermediate transfer body on which a toner image is transferred; a primary transfer means for primaryly transferring the toner image formed on the surface of the image holder to the surface of the intermediate transfer body; and a secondary transfer means for secondary transferring the toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium.

[0192] In the image forming apparatus according to this embodiment, for example, the part including the developing means may be a cartridge structure (process cartridge) that can be attached to and detached from the image forming apparatus. As the process cartridge, for example, a process cartridge equipped with a developing means containing the electrostatic image developer according to this embodiment is preferably used.

[0193] The following is an example of an image forming apparatus according to this embodiment, but it is not limited to this example. The main parts shown in the figure will be described, and other parts will be omitted from the explanation.

[0194] Figure 1 is a schematic diagram showing the image forming apparatus according to this embodiment. The image forming apparatus shown in Figure 1 is equipped with first to fourth electrophotographic image forming units 10Y, 10M, 10C, and 10K (image forming means) that output images of yellow (Y), magenta (M), cyan (C), and black (K) based on color-separated image data. These image forming units (hereinafter sometimes simply referred to as "units") 10Y, 10M, 10C, and 10K are arranged side by side at predetermined distances from each other in the horizontal direction. These units 10Y, 10M, 10C, and 10K may also be process cartridges that can be attached to and detached from the image forming apparatus.

[0195] In the drawings of each unit 10Y, 10M, 10C, and 10K, an intermediate transfer belt 20 is extended through each unit as an intermediate transfer body. The intermediate transfer belt 20 is wound around drive rolls 22 and support rolls 24 that are spaced apart from each other from left to right in the drawing and are in contact with the inner surface of the intermediate transfer belt 20, and is configured to travel in the direction from the first unit 10Y to the fourth unit 10K. The support rolls 24 are subjected to a force that moves away from the drive rolls 22 by a spring or the like (not shown), and tension is applied to the intermediate transfer belt 20 wound around both. In addition, an intermediate transfer body cleaning device 30 is provided on the side of the image holder of the intermediate transfer belt 20, facing the drive rolls 22. Furthermore, each of the developing devices (developing means) 4Y, 4M, 4C, and 4K for each unit 10Y, 10M, 10C, and 10K is supplied with toner containing four colors of toner: yellow, magenta, cyan, and black, contained in toner cartridges 8Y, 8M, 8C, and 8K.

[0196] Since the first to fourth units 10Y, 10M, 10C, and 10K have equivalent configurations, the first unit 10Y, which forms the yellow image and is located on the upstream side in the direction of travel of the intermediate transfer belt, will be described as a representative example. The descriptions of the second to fourth units 10M, 10C, and 10K will be omitted by assigning reference numerals to parts equivalent to the first unit 10Y, with magenta (M), cyan (C), and black (K) instead of yellow (Y).

[0197] The first unit 10Y has a photoreceptor 1Y that acts as an image holder. Around the photoreceptor 1Y are, in order, a charging roll (an example of a charging means) 2Y that charges the surface of the photoreceptor 1Y to a predetermined potential, an exposure device (an example of a static charge image forming means) 3 that exposes the charged surface with a laser beam 3Y based on a color-separated image signal to form a static charge image, a developing device (an example of a developing means) 4Y that supplies charged toner to the static charge image to develop the static charge image, a primary transfer roll 5Y (an example of a primary transfer means) that transfers the developed toner image onto an intermediate transfer belt 20, and a photoreceptor cleaning device (an example of a cleaning means) 6Y which has a cleaning blade 6Y-1 that removes toner remaining on the surface of the photoreceptor 1Y after primary transfer. The primary transfer roll 5Y is positioned inside the intermediate transfer belt 20, facing the photoreceptor 1Y. Furthermore, each of the primary transfer rolls 5Y, 5M, 5C, and 5K is connected to a bias power supply (not shown) that applies a primary transfer bias. Each bias power supply varies the transfer bias applied to each primary transfer roll through control by a control unit (not shown).

[0198] The following describes the process of forming the yellow image in the first unit 10Y. First, prior to operation, the surface of the photoreceptor 1Y is charged to a potential of -600V to -800V by the charging roll 2Y. The photoreceptor 1Y is conductive (e.g., volume resistivity at 20°C: 1 × 10⁻⁶). -6 The photosensitive layer is formed by laminating a photosensitive layer on a substrate (less than Ωcm). This photosensitive layer normally has high resistance (resistance of general resin), but when irradiated with a laser beam 3Y, the resistivity of the irradiated area changes. Therefore, a laser beam 3Y is output to the surface of the charged photoreceptor 1Y via the exposure device 3 according to image data for yellow sent from a control unit (not shown). The laser beam 3Y irradiates the photosensitive layer on the surface of the photoreceptor 1Y, thereby forming an electrostatic image of the yellow image pattern on the surface of the photoreceptor 1Y.

[0199] A static charge image is an image formed on the surface of a photoreceptor 1Y due to charging. It is a so-called negative latent image formed when the resistivity of the irradiated portion of the photoreceptor layer decreases due to the laser beam 3Y, causing the charged material on the surface of the photoreceptor 1Y to flow, while the charge remains in the portion not irradiated by the laser beam 3Y. The electrostatic charge image formed on the photoreceptor 1Y is rotated to a predetermined development position as the photoreceptor 1Y moves. At this development position, the electrostatic charge image on the photoreceptor 1Y is made visible as a toner image (developed image) by the developing device 4Y.

[0200] The developing device 4Y contains, for example, an electrostatic image developer including at least yellow toner and a carrier. The yellow toner is triboelectrically charged by being agitated inside the developing device 4Y and is held on the developer roll (an example of a developer holder) with a charge of the same polarity (negative polarity) as the static charge on the photoreceptor 1Y. As the surface of the photoreceptor 1Y passes through the developing device 4Y, the yellow toner electrostatically adheres to the discharged latent image on the surface of the photoreceptor 1Y, and the latent image is developed by the yellow toner. The photoreceptor 1Y, on which the yellow toner image has been formed, continues to move at a predetermined speed, and the toner image developed on the photoreceptor 1Y is transported to a predetermined primary transfer position.

[0201] When the yellow toner image on the photoreceptor 1Y is transported to the primary transfer, a primary transfer bias is applied to the primary transfer roll 5Y, and an electrostatic force from the photoreceptor 1Y toward the primary transfer roll 5Y acts on the toner image, transferring the toner image on the photoreceptor 1Y onto the intermediate transfer belt 20. The transfer bias applied at this time has a polarity opposite to the toner's polarity (-) (+), and in the first unit 10Y, for example, it is controlled to +10 μA by a control unit (not shown). Meanwhile, any toner remaining on the photoreceptor 1Y is removed and recovered by the photoreceptor cleaning device 6Y.

[0202] Furthermore, the primary transfer bias applied to the primary transfer rolls 5M, 5C, and 5K of the second unit from 10M onward is also controlled in accordance with the first unit. Thus, the intermediate transfer belt 20, on which the yellow toner image has been transferred in the first unit 10Y, is sequentially transported through the second to fourth units 10M, 10C, and 10K, and the toner images of each color are superimposed and transferred in multiple layers.

[0203] The intermediate transfer belt 20, on which four-color toner images have been multiple-transferred through the first to fourth units, proceeds to a secondary transfer section composed of the intermediate transfer belt 20, a support roll 24 in contact with the inner surface of the intermediate transfer belt, and a secondary transfer roll (an example of a secondary transfer means) 26 positioned on the image-holding surface side of the intermediate transfer belt 20. Meanwhile, recording paper (an example of a recording medium) P is fed via a supply mechanism into the gap between the secondary transfer roll 26 and the intermediate transfer belt 20 at a predetermined timing, and a secondary transfer bias is applied to the support roll 24. The transfer bias applied at this time has the same polarity (-) as the toner's polarity (-), and an electrostatic force from the intermediate transfer belt 20 toward the recording paper P acts on the toner image, transferring the toner image on the intermediate transfer belt 20 onto the recording paper P. The secondary transfer bias at this time is determined according to the resistance detected by a resistance detection means (not shown) that detects the resistance of the secondary transfer section, and is voltage-controlled.

[0204] After this, the recording paper P is fed to the contact area (nip area) of a pair of fixing rolls in a fixing device (an example of fixing means) 28, where the toner image is fixed onto the recording paper P, and a fixed image is formed.

[0205] Examples of recording paper P used to transfer toner images include plain paper used in electrophotographic photocopiers and printers. Other recording media besides recording paper P include OHP sheets. To further improve the smoothness of the image surface after fixing, it is preferable that the surface of the recording paper P is also smooth. For example, coated paper, which is plain paper coated with resin or the like, or art paper for printing are preferably used.

[0206] Once the color image has been fixed onto the recording paper P, it is discharged towards the output section, and the series of color image formation operations is completed.

[0207] <Processor Cartridges / Toner Cartridges> The process cartridge according to this embodiment will be described. The process cartridge according to this embodiment contains the electrostatic image developer according to this embodiment and includes a developing means for developing the electrostatic image formed on the surface of the image holder as a toner image using the electrostatic image developer, and is a process cartridge that can be attached to and detached from an image forming apparatus.

[0208] The process cartridge according to this embodiment is not limited to the above configuration, and may also include a developing device and, as necessary, at least one other means selected from, for example, an image holder, a charging means, an electrostatic image forming means, and a transfer means.

[0209] The following shows an example of a process cartridge according to this embodiment, but it is not limited to this example. The main parts shown in the figure will be described, and other parts will not be explained.

[0210] Figure 2 is a schematic diagram showing the process cartridge according to this embodiment. The process cartridge 200 shown in Figure 2 is constructed by integrally holding a photoreceptor 107 (an example of an image holder), a photoreceptor cleaning device 113 (an example of a cleaning device) having a charging roll 108 (an example of a charging means), a developing device 111 (an example of a developing means), and a cleaning blade 113-1, all of which are provided around the photoreceptor 107, within a housing 117 equipped with a mounting rail 116 and an opening 118 for exposure, and is thus formed into a cartridge. In Figure 2, 109 represents an exposure apparatus (an example of electrostatic image formation means), 112 represents a transfer apparatus (an example of a transfer means), 115 represents a fixing apparatus (an example of a fixing means), and 300 represents recording paper (an example of a recording medium).

[0211] Next, the toner cartridge according to this embodiment will be described. The toner cartridge according to this embodiment is a toner cartridge that contains the toner according to this embodiment and is attached to and detached from an image forming apparatus. The toner cartridge contains replenishment toner for supply to a developing means provided within the image forming apparatus.

[0212] The image forming apparatus shown in Figure 1 is an image forming apparatus with removable toner cartridges 8Y, 8M, 8C, and 8K. The developing units 4Y, 4M, 4C, and 4K are connected to toner cartridges corresponding to each developing unit (color) by toner supply pipes (not shown). When the toner contained in a toner cartridge becomes low, the toner cartridge is replaced. [Examples]

[0213] The embodiment will be described in more detail below with reference to examples and comparative examples, but this embodiment is not limited to these examples. Also, unless otherwise specified, "parts" and "%" are based on mass.

[0214] <Toner particle production> (Toner particles (1)) -Synthesis of amorphous polyester resin- • Bisphenol A ethylene oxide adduct [manufactured by Wako Pure Chemical Industries, Ltd.]: 150 copies • Bisphenol A propylene oxide adduct [manufactured by Wako Pure Chemical Industries, Ltd.]: 250 units • Tetrapropenyl succinic anhydride [manufactured by Wako Pure Chemical Industries, Ltd.]: 130 units Terephthalic acid [manufactured by Wako Pure Chemical Industries, Ltd.]: 100 units Trimethic acid [manufactured by Wako Pure Chemical Industries, Ltd.]: 15 parts The above monomer components were added to a reaction vessel equipped with a stirrer, thermometer, condenser, and nitrogen gas inlet tube. After replacing the reaction vessel with dry nitrogen gas, 0.3% tin dioctanoate was added relative to the total amount of the monomer components. The temperature was raised to 235°C over 1 hour under a nitrogen gas flow, and the reaction was allowed to proceed for 3 hours. The pressure inside the reaction vessel was then reduced to 10.0 mmHg, and the reaction was stirred until the desired molecular weight was reached, at which point the reaction was terminated. The obtained amorphous polyester resin 1 had a glass transition temperature of 61°C, a weight-average molecular weight of 42,000, and an acid value of 13 mgKOH / g. -Preparation of amorphous polyester resin dispersion- • Amorphous polyester resin: 100 parts • Methyl ethyl ketone: 60 parts Isopropyl alcohol: 10 parts The above components were added to a reaction vessel equipped with a stirrer and dissolved at 60°C. After confirming dissolution, the reaction vessel was cooled to 35°C, and then 3.5 parts of a 10% ammonia aqueous solution were added. Next, 300 parts of deionized water were added dropwise to the reaction vessel over 3 hours to prepare a polyester resin dispersion. Then, methyl ethyl ketone and isopropyl alcohol were removed using an evaporator to obtain an amorphous polyester resin dispersion.

[0215] -Preparation of a dispersion of coloring agent particles- • Cyan pigment [Pigment Blue 15:3, manufactured by Dainichi Seika Kogyo Co., Ltd.] 10 units • Anionic surfactant [Neogen SC, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.] 2 parts • Ion-exchanged water (80 bottles) The above components were mixed and dispersed for 1 hour using a high-pressure impact disperser Ultimizer [HJP30006, manufactured by Sugino Machine Co., Ltd.] to obtain a dispersion of colorant particles with a volume-average particle size of 180 nm and a solid content of 20%.

[0216] -Preparation of a release agent particle dispersion- • Paraffin wax [HNP 9, manufactured by Nippon Seiro Co., Ltd.] 50 units • Anionic surfactant [Neogen SC, manufactured by Daiichi Kogyo Seiyaku] 2 parts • Ion-exchanged water (200 copies) The above components were heated to 120°C, thoroughly mixed and dispersed in IKA's Ultra-Turrax T50, and then dispersed using a pressure-discharge homogenizer to obtain a release agent particle dispersion with a volume-average particle size of 200 nm and a solid content of 20%.

[0217] -Preparation of toner particles (1)- • Amorphous polyester resin particle dispersion: 210 parts • 25 parts of aqueous dispersion of coloring agent particles • Release agent particle dispersion 30 parts • 0.4 parts of polyaluminum chloride 100 bottles of deionized water The above components were placed in a stainless steel flask, thoroughly mixed and dispersed using IKA's Ultra-Turrax, and then heated to 48°C in a heating oil bath while stirring the flask. After holding at 48°C for 25 minutes, 70 parts of the same polyester resin dispersion were slowly added.

[0218] Subsequently, the pH of the system was adjusted to 8.0 using a 0.5 mol / L sodium hydroxide aqueous solution. The stainless steel flask was then sealed, the stirring shaft seal was magnetically sealed, and the mixture was heated to 90°C and held for 3 hours while stirring continued. After the reaction was complete, the mixture was cooled at a rate of 2°C / min, filtered, thoroughly washed with deionized water, and then solid-liquid separation was performed by Nutsche suction filtration. This was then redispersed with 3 L of deionized water at 30°C and stirred and washed at 300 rpm for 15 minutes. This washing operation was repeated six more times until the filtrate's pH reached 7.54 and its electrical conductivity reached 6.5 μS / cm. Solid-liquid separation was then performed using No. 5A filter paper by Nutsche suction filtration. Next, vacuum drying was continued for 12 hours to obtain toner particles (1). The volume-average particle size (D50v) of the toner particle (1) was 6.1 μm, and the average circularity was 0.965.

[0219] <Preparation of external additives> (Preparation of silica particles) [Silica particles 1, 3-36, 39-44] Silica particles 1, 3-36, and 39-44 were prepared as shown below.

[0220] -Preparation of alkaline catalyst solution- A glass reaction vessel equipped with a metal stirring rod, a dropping nozzle, and a thermometer contained methanol, deionized water, and aqueous ammonia (NH4OH) in the amounts and concentrations shown in Table 1, and was stirred and mixed to obtain an alkaline catalyst solution.

[0221] - Granulation of silica matrix particles using the sol-gel method - The temperature of the alkaline catalyst solution was adjusted to 40°C, and the alkaline catalyst solution was purged with nitrogen. Then, while stirring the alkaline catalyst solution, the amounts of tetramethoxysilane (TMOS) shown in Table 1 and 124 parts by mass of aqueous ammonia (NH4OH) with a catalyst (NH3) concentration of 7.9% were simultaneously added dropwise to obtain a silica matrix suspension.

[0222] - Addition of a trifunctional silane coupling agent - A silica mother particle suspension was heated to 40°C and stirred while adding the types and amounts of trifunctional silane coupling agents shown in Table 1 to the suspension. Stirring was then continued for 120 minutes to allow the trifunctional silane coupling agents to react. This resulted in the formation of an adsorption structure.

[0223] -Addition of nitrogen-containing compounds- Alcohol solutions were prepared by diluting the nitrogen-containing compounds of the types shown in Table 1 with butanol. Next, an alcohol solution obtained by diluting the nitrogen-containing compound with butanol was added to the suspension. The amount of alcohol solution added was such that the amount of nitrogen-containing compound per 100 parts by mass of the solid content of the silica matrix suspension was as shown in Table 1. The mixture was then stirred at 30°C for 100 minutes to obtain a suspension containing the nitrogen-containing compound.

[0224] -Drying- Next, 300 parts by mass of the suspension were placed in the reaction vessel, and CO2 was added while stirring, raising the temperature and pressure inside the reaction vessel to the temperatures and pressures shown in Table 1. While maintaining the temperature and pressure, CO2 was introduced and discharged at a flow rate of 5 L / min while stirring. After that, the solvent was removed over 120 minutes to obtain silica particles 1, 3-36, and 39-44.

[0225] [Silica particles 2] Silica particles 12 were obtained in the same manner as silica particles 1, except that spray drying was performed using a mini spray dryer B-290 (manufactured by Nippon Buch Co., Ltd.) under the conditions shown in Table 1, with the temperature and pressure inside the cylinder maintained and the silica particle suspension being delivered at a delivery rate of 0.2 L / hour.

[0226] [Silica particles 37] Silica particles 37 were obtained in the same manner as silica particles 11, except that after adding a nitrogen-containing compound, hexamethyldisilazane (HMDS) was added at 100% by mass relative to the solid content of the silica mother particles, and the mixture was stirred at 65°C for 3 hours to hydrophobize the surface of the silica mother particles.

[0227] [Silica particles 38] Silica particles 38 were obtained in the same manner as silica particles 11, except that 30 g of dry-process silica AEROSIL 130 (manufactured by Nippon Aerosil) was dispersed in 300 g of methanol to obtain a silica mother particle suspension.

[0228] [Silica particles C1, C2, C3] Silica particles C1, C2, and C3 were obtained in the same manner as silica particle 1, except that the types and amounts of the trifunctional silane coupling agent and nitrogen-containing compound were as shown in Table 1.

[0229] <Examples 1-44, Comparative Examples 1-3> To 100 parts of toner particles (1), 1.2 parts of the external additive shown in Table 2 were added, and the mixture was stirred in a Henschel mixer at a peripheral speed of 30 m / sec for 15 minutes to obtain the toner for each example.

[0230] Then, the obtained toners and carriers were placed in a V-blender in a toner:carrier ratio of 8:92 (by mass) and stirred for 20 minutes to obtain a developer.

[0231] The carrier used was created as follows: • Ferrite particles (volume-average particle size: 36 μm) 100 units • Toluene 14 parts • Styrene-methyl methacrylate copolymer 2 parts (Component ratio: 90 / 10, Mw=80000) • Carbon black (R330: manufactured by Cabot) 0.2 parts First, the above components, excluding the ferrite particles, were stirred with a stirrer for 10 minutes to prepare a dispersed coating solution. Next, this coating solution and the ferrite particles were placed in a vacuum-degassing kneader and stirred at 60°C for 30 minutes. After that, the carrier was obtained by degassing under reduced pressure while heating and drying.

[0232] <Evaluation of silica particles> (Various properties of silica particles) The following properties of the obtained silica particles were measured according to the method described above. • Number-average particle size (indicated as "particle size" in the table) • Average circularity (indicated as "Circularity" in the table) • Particle size distribution index (indicated as "particle size distribution" in the table) Pore ​​volume A for pores with a diameter of 1 nm to 50 nm, determined from the pore distribution curve of the nitrogen gas adsorption method before firing at 350°C (indicated as "Pore volume A before firing at 350°C" in the table). • Pore volume B for pores with a diameter of 1 nm to 50 nm, determined from the pore distribution curve of the nitrogen gas adsorption method after firing at 350°C (indicated as "Pore volume B after firing at 350°C" in the table). • Volume resistivity Ra before firing at 350°C (indicated as "Volume resistivity Ra before firing" in the table) • Volume resistivity Rb after firing at 350°C (indicated as "Volume resistivity Rb after firing" in the table) • Amount of OH groups measured by the Sears method (indicated as "Amount of OH groups" in the table) • Chemical shift of -50 ppm when the integral of all signals in the Si-CP / MAS NMR spectrum is set to 100%. from -75pp m The proportion of the integral value C of the signal observed within the range (indicated as "(Si-CP / MAS area ratio C)" in the table) • Chemical shift of -50 ppm in Si-CP / MAS NMR spectrum from -75pp m The integral value C of the signal observed within the range, and the chemical shift of -90 ppm. from -120pp m The ratio C / D of the integral value D of the signals observed within the range (indicated as "(Si-CP / MAS ratio C / D)" in the table). • Degree of hydrophobicity

[0233] (Charge dependence of low-humidity charge amount and high-humidity charge amount / capacitance) The low-humidity and high-humidity charge amounts of silica particles in each example were measured as follows, and the environmental dependence of capacitance was evaluated. Of the criteria, only A to B are acceptable. The evaluation method is as follows: 5g of a mixture containing 2% by mass of the prepared silica particles added to the surface of MA1010 manufactured by Nippon Shokubai was mixed with 50g of KNI106GSM manufactured by JFE Chemical Corporation. The above mixed sample was stirred for 5 minutes using a turbulent shaker in a 10°C 10%RH chamber, and the charge was measured using a Toshiba TB200. The result was denoted as FC, and the result was also determined by stirring for 5 minutes using a turbulent shaker in a 30°C 90%RH chamber, and measuring the charge using a Toshiba TB200. The ratio FA / FC was used for evaluation. A(◎): FA / FC is 0.8 or higher and less than 1.1 B(〇): FA / FC is 0.65 or higher and less than 0.8 C(△): FA / FC is between 0.5 and 0.65 D(×): FA / FC is less than 0.5

[0234] (Charge distribution under normal temperature and humidity conditions) The charge distribution of silica particles in each example was evaluated as follows under normal temperature and humidity conditions (20°C, 50% RH). 5g of a mixture containing 2% by mass of the prepared silica particles added to the surface of MA1010 manufactured by Nippon Shokubai was mixed with 50g of KNI106GSM manufactured by JFE Chemical Corporation. The above mixed sample was stirred for 5 minutes using a turbulent shaker in a 20°C 50%RH chamber and evaluated by CSG (Charge Spectrograph) image analysis. The charge distribution is defined as the value obtained by dividing the difference between the 20% charge Q(20) and the 80% charge Q(80) of the cumulative charge distribution by the 50% charge Q(50), i.e., [Q(80)-Q(20)] / Q(50). The evaluation criteria are as follows. A(◎): [Q(80)-Q(20)] / Q(50) value is less than 0.7 B(○): [Q(80)-Q(20)] / Q(50) value less than 0.8 and greater than or equal to 0.7 C(△): [Q(80)-Q(20)] / Q(50) value less than 1.0 and greater than or equal to 0.8 D(×): [Q(80)-Q(20)] / Q(50) value is 1.0 or higher

[0235] (Maintenance of a narrow charge distribution under normal temperature and humidity conditions) The ability of silica particles to maintain a narrow charge distribution under normal temperature and humidity conditions (20°C, 50% RH) was evaluated as follows. 5g of a mixture containing 2% by mass of the prepared silica particles added to the surface of Nippon Shokubai's MA1010 was mixed with 50g of JFE Chemical's KNI106GSM. The mixed sample was stirred for 100 minutes using a turbulent shaker in a 20°C 50%RH chamber and evaluated by CSG (Charge Spectrograph) image analysis. The charge distribution is defined as the difference between the 20% charge Q(20) and the 80% charge Q(80) of the cumulative charge distribution divided by the 50% charge Q(50), i.e., [Q(80)-Q(20)] / Q(50). The evaluation criteria are as follows. A(◎): [Q(80)-Q(20)] / Q(50) value is less than 0.75 B(○): [Q(80)-Q(20)] / Q(50) value less than 0.85 and greater than or equal to 0.75 C(△): [Q(80)-Q(20)] / Q(50) value less than 1.0 and greater than or equal to 0.85 D(×): [Q(80)-Q(20)] / Q(50) value is 1.0 or higher

[0236] The evaluation results are shown in Table 1. The details of the abbreviations in Table 1 are as follows: ·MTMS: Methyltrimethoxysilane • DTMS:n-dodecyltrimethoxysilane

[0237] ·TP-415:[ N( CH3)2(C 14 C H 29 )2]4Mo8O 26 (Manufactured by Hodogaya Chemical Co., Ltd., N,N-Dimethyl-N-tetradecyl-1-tetradecanaminium, hexa-μ-oxotetra-μ3-oxodi -μ5-oxotetradecaoxooctamolybdate(4-) (4:1)

[0238] <Toner Evaluation> (Cloud (toner scattering) in high temperature and high humidity environments) The toner cartridges were filled with the toners from each example and installed in an image forming machine (a modified ApeosPort-IV C5575 manufactured by Fujifilm Business Innovation Co., Ltd.). The developer for each example was filled into the developing unit of this image forming apparatus. It was left in an environment of 30°C / 90% relative humidity for 24 hours. After the period, 100,000 images with an image density of 1% were formed on A4 size paper at a rate of one sheet every 120 seconds. The image formed on the upper cover of the developing machine was transferred onto an OHP sheet using mending tape. The density of the transferred mending tape was measured at eight points at equal intervals using an X-Rite938 image densitometer (manufactured by X-Rite Corporation), and the difference between the density of the mending tape alone and the measured density was quantified as the amount of toner contamination inside the machine. The amount of toner contamination inside the machine was classified as follows according to the maximum density. Up to G3 is suitable for practical use. The evaluation criteria are as follows. -Evaluation Criteria- G1(◎): 0≦Δconcentration≦0.2 G2(〇): 0.2<Δconcentration≦0.4 G3(△): 0.4<Δconcentration≦0.6 G4(×): 0.6<Δconcentration≦0.8 G5(×): 0.8<Δconcentration

[0239] (Reproducibility of fine lines under high temperature and high humidity conditions) The fine line reproducibility was evaluated as follows: After evaluating cloud (toner splatter) under the high temperature and high humidity conditions described above, 1on1off images (images where 1-dot lines are arranged parallel to each other with 1-dot intervals) at a resolution of 2,400 dpi were printed as 5cm x 5cm charts perpendicular to the development direction on A4 paper, in the upper left, center, and lower right corners. The line spacing of each chart printed on the printed samples was observed using a magnifying glass with a 100x scale to check for areas where the spacing was narrowed due to toner splatter, etc., or areas where the spacing was widened due to the thinning of fine lines. The evaluation criteria are as follows: -Evaluation Criteria- G1 (◎): There is almost no decrease in distance due to toner splatter and almost no increase in distance due to thinning of the lines. G2(〇): A slight decrease or increase in distance is observed, but thin lines can be seen. G3(△): At least one chart where the spacing between lines is indistinguishable, or where thin lines are missing. G4 (×): At least two charts show that the spacing between thin lines is indistinguishable, or that thin lines are missing. G5 (×): If there are three or more charts where the spacing between thin lines cannot be determined, or where thin lines are missing.

[0240] (Wearing the hat in a normal temperature and humidity environment) The overlap was evaluated as follows: After evaluating the fineness of the image under the high temperature and high humidity conditions described above, the image was left in an environment of 20°C / 50% relative humidity for 24 hours. After this period, 10 images with an image density of 40% were formed consecutively on A4 size paper. The 10 images were observed with the naked eye and with a 5x magnification loupe, and the degree of haze was classified as follows. The evaluation criteria are as follows. -Evaluation Criteria- G1 (◎): No duplicates are allowed among the 10 cards. G2(〇): A slight haze is visible on one sheet under magnification, but it is not a problem. G3 (△): Slight haze is visible on several images under magnification, but it is minor and does not affect practical use. G4 (×): Multiple sheets show visible overhang, making them unsuitable for practical use. G5 (×): All 10 sheets show visible overexposure, making them unsuitable for practical use.

[0241] [Table 1-1]

[0242] [Table 1-2]

[0243] [Table 1-3]

[0244] [Table 2]

[0245] From the results above, it can be seen that in this embodiment, the occurrence of fogging under normal temperature and humidity conditions is suppressed compared to the comparative example. In particular, even when repeated images are formed under high temperature and high humidity conditions, fogging is suppressed and the image retention is excellent. Furthermore, this embodiment demonstrates that clouding and a decrease in fine-line reproducibility are also suppressed. [Explanation of symbols]

[0246] 1Y, 1M, 1C, 1K photoreceptors (examples of image retainers) 2Y, 2M, 2C, 2K Charging Rolls (Example of Charging Method) 3. Exposure apparatus (an example of electrostatic image formation means) 3Y, 3M, 3C, 3K laser beam 4Y, 4M, 4C, 4K developing apparatus (an example of a developing method) 5Y, 5M, 5C, 5K Primary Transfer Rolls (Example of Primary Transfer Method) 6Y, 6M, 6C, 6K Photoreceptor Cleaning Device (Example of Cleaning Method) 6Y-1, 6M-1, 6C-1, 6K-1 Cleaning Blades 8Y, 8M, 8C, 8K Toner Cartridges 10Y, 10M, 10C, 10K Image Forming Units 20. Intermediate transfer belt (an example of an intermediate transfer material) 22 Drive Roll 26. Secondary transfer roll (an example of a secondary transfer means) 30 Intermediate Transfer Body Cleaning Apparatus 107 Photoreceptor (an example of an image-retaining element) 108 Charging Roll (Example of Charging Method) 109 Exposure apparatus (an example of a means for forming electrostatic images) 111 Developing apparatus (an example of a developing means) 112 Transfer device (an example of a transfer means) 113 Photoreceptor cleaning device (an example of a cleaning method) 113-1 Cleaning Blade 115 Fixing device (an example of a fixing means) 116 Mounting Rail 118 Aperture for exposure 117 cabinets 200 Process Cartridges 300 Recording paper (an example of a recording medium) P Recording paper (an example of a recording medium)

Claims

1. Toner particles and Silica particles added to the toner particles, containing a nitrogen-containing compound, where A and B are the pore volumes of pores with diameters of 1 nm to 50 nm, determined from the pore distribution curve of the nitrogen gas adsorption method before and after firing at 350°C, respectively, B / A is 1.2 to 5, and B is 0.2 cm. ３ / g or more 3cm ３ Silica particles that are less than / g, It has, The silica particles comprise a silica matrix particle and a structure that coats at least a portion of the surface of the silica matrix particle and is composed of a reaction product of a trifunctional silane coupling agent, wherein at least a portion of the pores of the reaction product of the trifunctional silane coupling agent substantially adsorbs only a nitrogen-containing compound. The nitrogen-containing compound in the silica particles is at least one positively charged nitrogen-containing compound selected from the group consisting of quaternary ammonium salts, primary amine compounds, secondary amine compounds, tertiary amine compounds, amide compounds, imine compounds, and nitrile compounds. The measurement of the properties of the silica particles is performed on the silica particles obtained by separating them from the toner through the separation process described below, in a toner for electrostatic image development for a two-component developer. -Separation process- The dispersion containing the toner is subjected to ultrasonic homogenization at 20°C and 85 Watts for 30 minutes or more using an ultrasonic homogenizer. The dispersion is then centrifuged at high speed, and the supernatant is vacuum-dried at 80°C to obtain the silica particles.

2. The toner for developing electrostatic images according to claim 1, wherein the B / A ratio in the silica particles is 1.4 or more and 3 or less.

3. In the silica particles, the value of B is 0.3 cm. ３ / g or more 1.8cm ３ The electrostatic image developing toner according to claim 1 or claim 2, wherein the concentration is less than or equal to / g.

4. The electrostatic image developing toner according to any one of claims 1 to 3, wherein the number-average particle diameter of the silica particles is 10 nm or more and 200 nm or less.

5. The toner for developing electrostatic images according to claim 4, wherein the number-average particle diameter of the silica particles is 10 nm or more and 80 nm or less.

6. The electrostatic image developing toner according to any one of claims 1 to 5, wherein the average circularity of the silica particles is 0.60 or more and 0.96 or less.

7. The toner for developing electrostatic images according to claim 6, wherein the average circularity of the silica particles is 0.70 or more and 0.92 or less.

8. The volume resistivity of the silica particles is 1.0 × 10⁻⁶. ７ Ωcm or more: 1.0 × 10 １１．５ The electrostatic image developing toner according to any one of claims 1 to 7, wherein the value is Ωcm or less.

9. The electrostatic image developing toner according to any one of claims 1 to 8, wherein when the volume resistivity of the silica particles before and after firing at 350°C is Ra and Rb, respectively, Ra / Rb is 0.01 or more and 0.8 or less.

10. The cross-polarization / magic angle rotation (CP / MAS) method for the silica particles ２９ A toner for developing electrostatic images according to any one of claims 1 to 9, wherein the ratio C / D of the integral value C of the signal observed in the chemical shift range of -50 ppm to -75 ppm in a Si solid nuclear magnetic resonance (NMR) spectrum and the integral value D of the signal observed in the chemical shift range of -90 ppm to -120 ppm is 0.10 or more and 0.75 or less.

11. An electrostatic image developer comprising an electrostatic image developing toner according to any one of claims 1 to 10 and a carrier.

12. A toner for electrostatic image development according to any one of claims 1 to 10 is contained, A toner cartridge that is attached to and detached from an image forming machine.

13. The development means comprises a static charge image developer according to claim 11, and develops a static charge image formed on the surface of an image holder as a toner image using the static charge image developer, A process cartridge that is attached to and detached from an image forming apparatus.

14. Image holder and, A charging means for charging the surface of the image holder, A means for forming an electrostatic image on the surface of the charged image holder, A developing means comprising: containing the electrostatic image developer described in claim 11; and developing the electrostatic image formed on the surface of the image holder as a toner image using the electrostatic image developer; A transfer means for transferring a toner image formed on the surface of the image holder to the surface of a recording medium, A cleaning means having a cleaning blade for cleaning the surface of the image holder, Fixing means for fixing the toner image transferred to the surface of the recording medium, An image forming apparatus equipped with the following features.

15. A charging process to charge the surface of the image holder, A step of forming an electrostatic image on the surface of the charged image holder, A developing step of developing the electrostatic image formed on the surface of the image holder as a toner image using the electrostatic image developer according to claim 11, A transfer step of transferring the toner image formed on the surface of the image holder to the surface of the recording medium, A cleaning step in which the surface of the image holder is cleaned with a cleaning blade, A fixing step for fixing the toner image transferred to the surface of the recording medium, An image forming method having the following characteristics.

Images