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

Abstract

This invention provides a toner for electrostatic image development that suppresses initial image fogging that occurs when the toner is stored for a long period of time and then formed under high temperature and high humidity conditions. [Solution] A toner for developing electrostatic images, comprising toner particles containing a binder resin and a pigment containing a fluorescent organic pigment, wherein the pigment content is 4.0% by mass or more and 20.0% by mass or less relative to the toner particles, the water absorption rate of the toner particles is 1.0% or less, at least a portion of the pigment is exposed on the surface of the toner particles, and the coating rate of the exposed pigment on the surface of the toner particles by the oil is 20% or more.

Description

[Technical Field]

[0001] This disclosure relates to a toner for electrostatic image development, a method for manufacturing an electrostatic image development toner, an electrostatic image developer, a toner cartridge, a process cartridge, and an image forming apparatus. [Background technology]

[0002] Patent Document 1 discloses a toner for electrostatic image development, comprising toner particles containing a binder resin including a polyester resin and a styrene (meth)acrylic resin, wherein the styrene (meth)acrylic resin forms domains with an average diameter of 300 nm to 800 nm within the toner particles, and an external additive containing oil-treated silica particles with an oil release amount of 3% to 30% by mass. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2016-224339 [Overview of the project] [Problems that the invention aims to solve]

[0004] The object of the present invention is to provide an electrostatic image developing toner having toner particles containing a binder resin and a pigment including a fluorescent organic pigment, wherein the pigment content is 4.0% by mass or more and 20.0% by mass or less relative to the toner particles, and which suppresses initial image fogging that occurs when the toner is stored for a long period of time and an image is formed under high temperature and high humidity conditions. [Means for solving the problem]

[0005] The following embodiments are included as specific means for solving the aforementioned problems.

[0006] <1> A toner for developing electrostatic images, comprising toner particles containing a binder resin and a pigment including a fluorescent organic pigment, wherein the pigment content is 4.0% by mass or more and 20.0% by mass or less relative to the toner particles, the water absorption rate of the toner particles is 1.0% or less, at least a portion of the pigment is exposed on the surface of the toner particles, and the oil coating rate of the pigment exposed on the surface of the toner particles is 20% or more. <2> The fluorescent organic pigment comprises an azomethine compound having an emission peak wavelength of 500 nm or more and 550 nm or less. <1> Toner for developing electrostatic images as described above. <3> The aforementioned pigment includes a non-fluorescent organic pigment having a reflectance peak wavelength of 480 nm to 540 nm. <1> or <2> Toner for developing electrostatic images as described above. <4> When the surface of the toner particles is observed, the proportion of the area occupied by the pigment exposed on the surface of the toner particles is 10% or more and 50% or less of the total surface area of ​​the toner particles. <1> ~ <3> A toner for developing electrostatic images, as described in one of the following. <5> The content of the fluorescent organic pigment relative to the toner particles is 3.0% by mass or more and 15.0% by mass or less. <1> ~ <4> A toner for developing electrostatic images, as described in one of the following. <6> The external additive includes oil-treated silica particles treated with the aforementioned oil. <1> ~ <5> Toner for developing electrostatic images as described above. <7> The content of the oil-treated silica particles is 0.5% by mass or more and 5.0% by mass or less relative to the toner particles. <6> Toner for developing electrostatic images as described above. <8> The amount of oil released from the oil-treated silica particles relative to the oil-treated silica particles is 5.0% by mass or more and 30.0% by mass or less. <6> Toner for developing electrostatic images as described above. <9> The volume-average particle size of the oil-treated silica particles is between 15.0 nm and 200 nm. <6> Toner for developing electrostatic images as described above. <10> The average circularity of the toner particles is less than 0.940. <1> ~ <9> A toner for developing electrostatic images, as described in one of the following. <11> The process includes a kneading step of kneading the binder resin and the pigment containing the fluorescent organic pigment to obtain a kneaded product, and a pulverizing step of pulverizing the obtained kneaded product to obtain toner particles. <1> ~ <10> A method for manufacturing electrostatic image developing toner as described in any one of the following. <12> <1> ~ <10> A electrostatic image developer containing an electrostatic image developing toner as described in any one of the following. <13> <1> ~ <10> A toner cartridge that contains the electrostatic image developing toner described in any one of the above, and is attached to and detached from an image forming apparatus. <14> <12> A process cartridge that is attached to and detached from an image forming apparatus, comprising a developing device that contains the electrostatic image developer described above and develops an electrostatic image formed on the surface of an image holder as a toner image using the electrostatic image developer. <15> An image holder, a charging device for charging the surface of the image holder, and an electrostatic image forming device for forming an electrostatic image on the charged surface of the image holder, <12> An image forming apparatus comprising: a developing device that contains the electrostatic image developer described in [reference] and develops the electrostatic image formed on the surface of the image holder as a toner image using the electrostatic image developer; a transferring device that transfers the toner image formed on the surface of the image holder to the surface of a recording medium; and a fixing device that fixes the toner image transferred to the surface of the recording medium. [Effects of the Invention]

[0007] <1> According to the invention, an electrostatic image developing toner is provided having toner particles containing a binder resin and a pigment including a fluorescent organic pigment, wherein the pigment content is 4.0% by mass or more and 20.0% by mass or less relative to the toner particles. Compared to cases where the water absorption rate of the toner particles exceeds 1.0% or the oil coating rate of the pigment exposed on the surface of the toner particles is less than 20%, an electrostatic image developing toner is provided in which initial image fogging that occurs when an image is formed under high temperature and high humidity after the toner has been stored for a long period of time is suppressed. <2> According to the invention, an electrostatic image developing toner is provided which has toner particles containing a binder resin and a pigment containing a fluorescent organic pigment, wherein the pigment content is 4.0% by mass or more and 20.0% by mass or less relative to the toner particles, and which can form a fluorescent yellow image with suppressed initial image fogging that occurs when the toner is stored for a long period of time and then formed under high temperature and high humidity conditions, compared to cases where the water absorption rate of the toner particles exceeds 1.0% or the oil coating rate of the pigment exposed on the surface of the toner particles is less than 20%. <3> According to the invention, an electrostatic image developing toner is provided which has toner particles containing a binder resin and a pigment containing a fluorescent organic pigment, wherein the pigment content is 4.0% by mass or more and 20.0% by mass or less relative to the toner particles, and which can form a fluorescent green image with suppressed initial image fogging that occurs when the toner is stored for a long period of time and then formed under high temperature and high humidity conditions, compared to cases where the water absorption rate of the toner particles exceeds 1.0% or the oil coating rate of the pigment exposed on the surface of the toner particles is less than 20%. <4> According to the invention, when the surface of the toner particles is observed, the proportion of the area occupied by the pigment exposed on the surface of the toner particles is less than 10% or more than 50% of the total surface area of ​​the toner particles. Compared to this invention, an electrostatic image developing toner is provided in which initial image fogging that occurs when the toner is stored for a long period of time and an image is formed under high temperature and high humidity conditions is suppressed. <5> According to the invention, compared to cases where the content of fluorescent organic pigment relative to toner particles exceeds 15.0% by mass, an electrostatic image developing toner is provided in which initial image fogging that occurs when the toner is stored for a long period of time and then an image is formed under high temperature and high humidity conditions is suppressed. <6> According to the invention, compared to cases where the toner contains silica particles that have not been treated with oil as an external additive, an electrostatic image developing toner is provided in which initial image fogging that occurs when the toner is stored for a long period of time and then an image is formed under high temperature and high humidity conditions is suppressed. <7> According to the invention, compared to cases where the oil-treated silica particle content is less than 0.5% by mass or more than 5.0% by mass relative to the toner particles, an electrostatic image developing toner is provided in which initial image fogging that occurs when the toner is stored for a long period of time and then an image is formed under high temperature and high humidity conditions is suppressed. <8> According to the invention, compared to a case where the amount of oil released from oil-treated silica particles relative to the oil-treated silica particles is less than 5.0% by mass, an electrostatic image developing toner is provided in which initial image fogging that occurs when an image is formed under high temperature and high humidity after the toner has been stored for a long period of time is suppressed. <9> According to the invention, compared to the case where the volume average particle size of the oil-treated silica particles is less than 15.0 nm, an electrostatic image developing toner is provided in which initial image fogging that occurs when the toner is stored for a long period of time and then an image is formed under high temperature and high humidity conditions is suppressed. <10> According to the invention, in an electrostatic image developing toner having toner particles containing a binder resin and a pigment including a fluorescent organic pigment, wherein the pigment content is 4.0% by mass or more and 20.0% by mass or less relative to the toner particles, compared to cases where the water absorption rate of the toner particles exceeds 1.0% or the oil coating rate of the pigment exposed on the surface of the toner particles is less than 20%, an electrostatic image developing toner is provided in which initial image fogging that occurs when the toner is stored for a long period of time and an image is formed under high temperature and high humidity is suppressed, even if the toner particles are irregularly shaped. According to the invention of <11>, there is provided a method for producing a toner for developing electrostatic images, the toner having toner particles containing a binder resin and a pigment including a fluorescent organic pigment, wherein the content of the pigment is 4.0% by mass or more and 20.0% by mass or less based on the toner particles. Compared to the case where the water absorption rate of the toner particles exceeds 1.0%, or the coverage of the pigment exposed on the surface of the toner particles with oil is less than 20%, the toner for developing electrostatic images in which fogging in an initial image, which occurs when an image is formed under high temperature and high humidity after the toner is stored for a long period of time produced by a kneading and pulverizing method, is suppressed can be obtained. According to the invention according to <12>, <13>, <14> or <15>, there is provided a toner cartridge, a process cartridge, or an image forming apparatus, comprising a toner for developing electrostatic images, the toner having toner particles containing a binder resin and a pigment including a fluorescent organic pigment, wherein the content of the pigment is less than 4.0% by mass or more than 20.0% by mass based on the toner particles, the water absorption rate of the toner particles exceeds 1.0%, at least a part of the pigment is exposed on the surface of the toner particles, and compared to the case where the coverage of the pigment exposed on the surface of the toner particles with oil is less than 20%, fogging in an initial image, which occurs when an image is formed under high temperature and high humidity after the toner is stored for a long period of time, is suppressed. [BRIEF DESCRIPTION OF THE DRAWINGS]

[0008] [Figure 1] It is a diagram illustrating the state of a screw of an example of a screw extruder used for producing the toner for developing electrostatic images of the present invention. [Figure 2] It is a schematic configuration diagram showing an example of the image forming apparatus according to the present embodiment. [Figure 3] It is a schematic configuration diagram showing an example of a process cartridge detachably attachable to the image forming apparatus according to the present embodiment. [MODE FOR CARRYING OUT THE INVENTION]

[0009] Hereinafter, embodiments of the present disclosure will be described. These descriptions and examples exemplify the embodiments, and do not limit the scope of the embodiments.

[0010] In this disclosure, the numerical range indicated using "~" represents a range that includes the numbers before and after "~" as the minimum and maximum values, respectively. In numerical ranges described in stages within this disclosure, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Furthermore, in numerical ranges described within this disclosure, the upper or lower limit of that range may be replaced with the values ​​shown in the examples.

[0011] In this disclosure, the term "process" includes not only independent processes but also processes that cannot be clearly distinguished from other processes, provided that their objectives are achieved.

[0012] When embodiments are described in this disclosure with reference to the drawings, the configuration of such embodiments is not limited to the configuration shown in the drawings. Furthermore, the sizes of the components in each figure are conceptual, and the relative relationships between the components are not limited thereto.

[0013] In this disclosure, each component may contain multiple types of the corresponding substance. When referring to the amount of each component in a composition in this disclosure, if there are multiple types of the substance corresponding to each component in the composition, it means the total amount of those multiple types of substances present in the composition unless otherwise specified. In this disclosure, each component may contain multiple types of particles. If multiple types of particles corresponding to each component are present in the composition, the particle size of each component refers to the value for a mixture of such multiple types of particles present in the composition, unless otherwise specified.

[0014] In this disclosure, alkyl groups include linear, branched, and cyclic alkyl groups unless otherwise specified.

[0015] In this disclosure, organic groups, aromatic rings, linking groups, alkyl groups, aryl groups, aralkyl groups, alkoxy groups, and aryloxy groups may have hydrogen atoms substituted by halogen atoms.

[0016] <Toner for developing electrostatic images> The electrostatic image developing toner (hereinafter also referred to as toner) according to this embodiment includes toner particles containing a binder resin and a pigment containing a fluorescent organic pigment. The pigment content is between 4.0% by mass and 20.0% by mass relative to the toner particles. The water absorption rate of toner particles is 1.0% or less. Furthermore, at least a portion of the pigment is exposed on the surface of the toner particles, and the oil coating rate of the pigment exposed on the surface of the toner particles is 20% or more.

[0017] The toner according to this embodiment, with the above configuration, is a toner for electrostatic image development in which initial image fogging that occurs when the toner is stored for a long period of time and then formed under high temperature and high humidity is suppressed. The reason for this is presumed to be as follows.

[0018] Conventionally, it is known that toners containing fluorescent organic pigments (hereinafter also referred to as "fluorescent toners") are used to broaden the color gamut of images. On the other hand, fluorescent toner is used less frequently than other colored toners such as cyan, magenta, yellow, and black toner. Therefore, fluorescent toners tend to have long periods between production and use, and between use and reuse. In other words, fluorescent toners are often stored for extended periods. However, when fluorescent toner is stored for a long period of time, if an image is formed under high temperature and high humidity conditions, the toner's chargeability may decrease due to moisture absorption, which can cause fogging of the initial image. In particular, when the pigment content in toner particles is set to 4.0% by mass or more and 20.0% by mass or less, the pigment becomes more easily exposed from the toner particles. Since pigment is a compound with crystals that have low electrical resistance, when the pigment is exposed from the toner particles, leakage occurs from the exposed pigment area, and the chargeability of the toner tends to decrease. As a result, initial image fogging is more likely to occur.

[0019] Therefore, in the toner according to this embodiment, the water absorption rate of the toner particles is reduced to 1.0% or less. This suppresses the decrease in the electrostatic properties of the toner due to moisture absorption. In addition, the pigment exposed on the surface of the toner particles is coated with oil, and the oil coating rate of the pigment is set to 20% or more. This suppresses the decrease in the toner's chargeability due to leakage current from the exposed pigment parts through the oil coating.

[0020] For the reasons stated above, it is presumed that the toner according to this embodiment will be a toner for electrostatic image development in which initial image fogging that occurs when the toner is stored for a long period of time and then formed under high temperature and high humidity conditions is suppressed.

[0021] The following describes the details of the toner according to this embodiment.

[0022] The toner according to this embodiment includes toner particles. The toner according to this embodiment may also include an external additive.

[0023] [Toner particles] The toner particles contain a binder resin and a pigment containing a fluorescent organic pigment. The toner particles may also contain a release agent, internal resin particles, and other additives.

[0024] (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, as well as mixtures of these with vinyl resins, or 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.

[0025] Polyester resin is preferred as the binder resin. Examples of polyester resins include well-known polyester resins.

[0026] Examples of polyester resins include condensation polymers of polycarboxylic acids and polyhydric alcohols.

[0027] 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, orthophthalic 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.

[0028] 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.

[0029] 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".

[0030] 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.

[0031] 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, 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.

[0032] Furthermore, the polyester resin may be a hybrid resin having a polyester resin segment and a styrene-acrylic copolymer segment.

[0033] The binder resin content is preferably 40% to 95% by mass, more preferably 50% to 90% by mass, and even more preferably 60% to 90% by mass, relative to the total toner particles.

[0034] (Pigment) The pigment may include a fluorescent organic pigment. The pigment may also include a non-fluorescent organic pigment along with the fluorescent organic pigment. Fluorescent organic pigments are organic pigments that emit light in response to external light energy. Non-fluorescent organic pigments are organic pigments that do not emit light in response to external light energy. Generally, fluorescent organic pigments exhibit color through both reflected and emitted light, while non-fluorescent organic pigments exhibit color through reflected light only.

[0035] Here, the pigment content is 4.0% by mass or more and 20.0% by mass or less relative to the toner particles, preferably 5.0% by mass or more and 18.0% by mass or less, and more preferably 6.0% by mass or more and 15.0% by mass or less. When the pigment content is 4.0% by mass or more, it becomes easier to form an image of the desired color (for example, an image with sufficient fluorescence intensity). By limiting the pigment content to 20.0% by mass or less, the pigment is not sufficiently dispersed within the toner particles, suppressing the generation of large-diameter pigments. This prevents an excessive increase in the surface area of ​​pigment exposed on the toner particle surface, thereby suppressing a decrease in toner's chargeability and initial image fogging. Furthermore, it also suppresses color streaks caused by the development of large-diameter pigments.

[0036] -Fluorescent organic pigments- Fluorescent organic pigments are not limited in color or other characteristics as long as they are organic pigments that possess fluorescence. Examples include fluorescent yellow organic pigments, fluorescent pink organic pigments, fluorescent red organic pigments, fluorescent orange organic pigments, fluorescent green organic pigments, and fluorescent purple organic pigments.

[0037] Examples of fluorescent organic pigments include azomethine compounds, isoindolinone compounds, xanthene compounds (including rhodamine compounds, fluorescein compounds, and eosin compounds), naphthalene compounds, and triarylmethane compounds. In particular, the fluorescent organic pigment is preferably an azomethine compound having an emission peak wavelength of 500 nm to 550 nm, and more preferably a bisazomethine compound having an emission peak wavelength of 500 nm to 550 nm. When these azomethine compounds are applied, a fluorescent yellow image with good fluorescence intensity can be formed.

[0038] Here, the emission peak wavelength is measured using a UV-3600 spectrophotometer (manufactured by Shimadzu Corporation), based on the measurement method specified in the Japanese Industrial Standard (JIS K 5101-3-3).

[0039] Azomethine compounds include -R 1 C=N-(R 1 Examples include compounds having an azomethine structure represented by a hydrogen atom or a monovalent substituent. As for bisazometine compounds, -R 1 C=NN=CR 2 -(R 1 and R 2 Examples include compounds having a bisazomethine structure in their molecular structure, each independently represented by a hydrogen atom or a monovalent substituent.

[0040] Fluorescent organic pigments preferably have hydrophilic groups. Examples of hydrophilic groups in fluorescent organic pigments include hydroxyl groups, primary to tertiary amino groups, carboxyl groups, sulfo groups, and phosphate groups. In particular, fluorescent organic pigments are preferably those that have a hydroxyl group as a hydrophilic group.

[0041] Examples of fluorescent organic pigments include the following azomethine compounds (1) to (3).

[0042] -Azomethine fluorescent organic pigment- [ka]

[0043] The emission peak wavelength of azomethine compound (1) is 520 nm. The emission peak wavelength of azomethine compound (2) is 510 nm. The emission peak wavelength of azomethine compound (3) is 520 nm.

[0044] Furthermore, derivatives of azomethine compounds are also preferred examples of fluorescent organic pigments, and boron difluoride derivatives of azomethine compounds are more preferred examples. Examples of boron difluoride derivatives of azomethine compounds include the following compounds.

[0045] [ka]

[0046] The fluorescent organic pigment is preferably at least one selected from the group consisting of azomethine compound (1), azomethine compound (2), azomethine compound (3), and boron difluoride derivatives thereof.

[0047] Furthermore, as the fluorescent organic pigment, CI Pigment Yellow 101 or a boron difluoride derivative of CI Pigment Yellow 101 is preferred, and more preferably, CI Pigment Yellow 101 as shown in azomethine compound (1) is preferred.

[0048] The content of the fluorescent organic pigment is preferably 3.0% by mass or more and 15.0% by mass or less relative to the toner particles, more preferably 4.0% by mass or more and 13.0% by mass or less, and even more preferably 5.0% by mass or more and 10.0% by mass or less. When the fluorescent organic pigment content is 3.0% by mass or more, an image with sufficient fluorescence intensity can be formed. When the fluorescent organic pigment content is 15.0% by mass or less, the pigment disperses more easily in the toner, suppressing the formation of large pigment particles. As a result, the surface area of ​​the pigment exposed on the toner particle surface is less likely to increase excessively. Consequently, the decrease in the toner's electrostatic properties is suppressed, and initial image fogging is less likely to occur. In addition, color streaks caused by the development of large-diameter pigments are less likely to occur.

[0049] -Non-fluorescent organic pigments- The toner particles contain non-fluorescent organic pigments. Non-fluorescent organic pigments are organic pigments that do not possess fluorescence, and there are no restrictions on their color, etc. Examples include non-fluorescent green organic pigments, non-fluorescent red organic pigments, non-fluorescent yellow organic pigments, non-fluorescent pink organic pigments, non-fluorescent orange organic pigments, and non-fluorescent purple organic pigments. In particular, non-fluorescent organic pigments with a reflection peak wavelength of 480 nm to 540 nm (hereinafter referred to as "specific non-fluorescent organic pigments") are preferred. In particular, when an azomethine compound with an emission peak wavelength of 500 nm to 550 nm is used in combination with a specific non-fluorescent organic pigment, a fluorescent green image with good fluorescence intensity can be formed. Here, the reflection peak wavelength is measured using the same method as the emission peak wavelength of the fluorescent organic pigment described above.

[0050] From the viewpoint of reflectivity, it is preferable that the specific non-fluorescent organic pigment contains halogen atoms. Examples of halogen atoms in specific non-fluorescent organic pigments include fluorine, chlorine, bromine, and iodine atoms. In particular, from the viewpoint of reflectance, the specific non-fluorescent organic pigment preferably has at least one halogen atom selected from the group consisting of chlorine atoms and bromine atoms, more preferably has a bromine atom, and especially preferably has both a chlorine atom and a bromine atom. Furthermore, from the viewpoint of reflectance, the specific non-fluorescent organic pigment preferably has two or more halogen atoms, more preferably has four or more halogen atoms, even more preferably has two or more halogen atoms, and particularly preferably has eight to 32 halogen atoms.

[0051] Examples of specific non-fluorescent organic pigments include lake pigments of halogenated phthalocyanine compounds and halogenated triphenylmethane dyes. As the specific non-fluorescent organic pigment, halogenated phthalocyanine compounds are preferred, and at least one selected from the group consisting of copper phthalocyanine halide and zinc phthalocyanine halide is preferred, with copper phthalocyanine halide being more preferred. Examples of copper phthalocyanine halides include CI Pigment Green 7 (specific gravity 2.1, reflection peak wavelength 500 nm, containing 16 chlorine atoms) and CI Pigment Green 36 (specific gravity 2.9, reflection peak wavelength 510 nm, containing 10 chlorine atoms and 6 bromine atoms).

[0052] The content of the non-fluorescent organic pigment is selected according to the fluorescence color of the desired fluorescent image, but is preferably 1.0% to 17.0% by mass relative to the toner particles, more preferably 1.5% to 12.0% by mass, and even more preferably 2.0% to 8.0% by mass.

[0053] (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.

[0054] 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".

[0055] The release agent content is preferably 1% to 20% by mass, and more preferably 4% to 15% by mass, relative to the total toner particles.

[0056] -Internal resin particles- Examples of internally added resin particles include polyolefin resins (polyethylene, polypropylene, etc.), styrene resins (polystyrene, α-polymethylstyrene, etc.), (meth)acrylic resins (polymethyl methacrylate, polyacrylonitrile, etc.), epoxy resins, polyurethane resins, polyurea resins, polyamide resins, polycarbonate resins, polyether resins, polyester resins, and copolymer resins thereof. Styrene-(meth)acrylic copolymer resin particles are preferred as the internally added resin particles.

[0057] Examples of styrene-(meth)acrylic copolymer resin particles include resin particles obtained by polymerizing styrene monomers and (meth)acrylic acid monomers by radical polymerization.

[0058] Examples of styrene monomers include styrene, α-methylstyrene, vinylnaphthalene, alkyl-substituted styrenes having alkyl chains such as 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, and 4-ethylstyrene, halogen-substituted styrenes such as 2-chlorostyrene, 3-chlorostyrene, and 4-chlorostyrene, and fluorine-substituted styrenes such as 4-fluorostyrene and 2,5-difluorostyrene. Among these, styrene and α-methylstyrene are preferred as styrene monomers.

[0059] Examples of (meth)acrylic acid monomers include (meth)acrylic acid, n-methyl (meth)acrylate, n-ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, n-lauryl (meth)acrylate, n-tetradecyl (meth)acrylate, n-hexadecyl (meth)acrylate, n-octadecyl (meth)acrylate, isopropyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, isopentyl (meth)acrylate, amyl (meth)acrylate, (meth)acrylate Examples of (meth)acrylic acid monomers include neopentyl acrylate, isohexyl methacrylate, isoheptyl methacrylate, isooctyl methacrylate, 2-ethylhexyl methacrylate, phenyl methacrylate, biphenyl methacrylate, diphenylethyl methacrylate, t-butylphenyl methacrylate, terphenyl methacrylate, cyclohexyl methacrylate, t-butylcyclohexyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, methoxyethyl methacrylate, 2-hydroxyethyl methacrylate, β-carboxyethyl methacrylate, acrylonitrile, and methacrylamide. Among these, n-butyl methacrylate and β-carboxyethyl methacrylate are preferred as (meth)acrylic acid monomers.

[0060] The internally added resin particles are preferably crosslinked resin particles. In crosslinked resin particles, the crosslinking agent for crosslinking the resin is, for example, aromatic polyhydric vinyl compounds such as divinylbenzene and divinylnaphthalene; polyhydric vinyl esters of aromatic polyhydric carboxylic acids such as divinyl phthalate, divinyl isophthalate, divinyl terephthalate, divinyl homophthalate, divinyl trimesicate, trivinyl trimesicate, divinyl naphthalenedicarboxylate, and divinyl biphenylcarboxylate; divinyl esters of nitrogen-containing aromatic compounds such as divinyl pyridinedicarboxylate; vinyl esters of unsaturated heterocyclic carboxylic acid compounds such as vinyl pyromutinate, vinyl furanate, pyrrole-2-carboxylate, and vinyl thiophenecarboxylate; butanediol methacrylate, etc. Examples include (meth)acrylic acid esters of linear polyhydric alcohols such as xanediol acrylate, hexanediol dimethacrylate, octanediol diacrylate, octanediol methacrylate, nonanediol diacrylate, nonanediol dimethacrylate, decanediol acrylate, decanediol dimethacrylate, dodecanediol diacrylate, and dodecanediol methacrylate; (meth)acrylic acid esters of branched and substituted polyhydric alcohols such as neopentyl glycol dimethacrylate and 2-hydroxy, 1,3-diacryloxypropane; and polyethylene glycol di(meth)acrylate and polypropylene polyethylene glycol di(meth)acrylate. The crosslinking agent may be used alone or in combination of two or more types.

[0061] Examples of copolymer resin particles of a styrene monomer and a (meth)acrylic acid monomer include copolymer resin particles in which the styrene monomer is styrene, the (meth)acrylic acid monomer is n-butyl acrylate, and the mass ratio of the styrene monomer to the (meth)acrylic acid monomer (styrene monomer to (meth)acrylic acid monomer) is 70 / 30 or more and 10 / 90 or less (preferably 65 / 35 or more and 20 / 80 or less). Furthermore, in the case of crosslinked resin particles using a crosslinking agent, a bifunctional alkyl acrylate having an alkylene chain with 6 to 12 carbon atoms is preferred as the crosslinking agent. The content of the crosslinking agent is preferably 0.3 parts by mass to 5.0 parts by mass, more preferably 0.5 parts by mass to 2.5 parts by mass, and even more preferably 1.0 part by mass to 2.0 parts by mass, based on 100 parts by mass of the total of the styrene monomer, (meth)acrylic acid monomer, and crosslinking agent.

[0062] The average primary particle size of the internally added resin particles is preferably 50 nm to 500 nm, more preferably 20 nm to 300 nm, and even more preferably 30 nm to 250 nm. When the average primary particle size of the internally added resin particles is within the above range, the internally added resin particles are less likely to aggregate within the toner particles and tend to exist at an appropriate size.

[0063] The average primary particle size of the internally added resin particles is a value measured using a transmission electron microscope (TEM). For example, the JEM-2100plus, manufactured by JEOL Ltd., can be used as a transmission electron microscope. Specifically, the method for measuring the average primary particle size of the internally added resin particles is as follows: The toner particles are cut into pieces approximately 0.1 μm thick using a microtome. A 10,000x magnification image of the cross-section of the toner particles is taken using a transmission electron microscope. For 100 internal resin particles dispersed within the toner particles, the equivalent diameter of each circle is calculated from the individual cross-sectional area, and the arithmetic mean of these values ​​is used as the average primary particle size.

[0064] The content of internally added resin particles is preferably 2% to 30% by mass, more preferably 3% to 25% by mass, and even more preferably 5% to 20% by mass, relative to the toner particles.

[0065] -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.

[0066] [Characteristics of toner particles, etc.] (Water absorption rate of toner particles) The water absorption rate of the toner particles is 1.0% or less, more preferably 0.9% or less, and even more preferably 0.8% or less.

[0067] If the water absorption rate of toner particles is 1.0% or less, the progression of water absorption by toner particles during long-term storage can be suppressed. This reduces the electrostatic charge and suppresses the occurrence of initial image fogging.

[0068] One method for adjusting the water absorption rate of toner particles to the above range is to reduce the amount of surfactant contained in the toner particles. Specifically, the surfactant content in toner particles is preferably 0% by mass or more and 1.0% by mass or less, and more preferably 0% by mass or more and 0.8% by mass or less. In other words, the surfactant is either not contained in the toner particles, or if it is contained, it is preferably 1.0% by mass or less, and more preferably 0.8% by mass or less.

[0069] Here, a surfactant refers to a compound that has both a hydrophilic group and a hydrophobic group in a single molecule. This includes any of the well-known surfactants: anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants.

[0070] The water absorption rate of toner particles is calculated using the following method. The toner particles (or toner) to be measured are immersed in boiling hot water for 1 hour, and the mass W1 of the water-absorbing toner particles (or toner) is measured. Next, the water-absorbing toner particles (or toner) are dried at 120°C for 2 hours, and the mass W2 of the dried toner particles (or toner) is measured. Then, the water absorption rate of the toner particles (or toner) is calculated using the following formula. Water absorption rate (mass%) = (W1-W2) / W2×100

[0071] (Pigment coating with oil) In the toner according to this embodiment, at least a portion of the pigment is exposed on the surface of the toner particles, and the pigment exposed on the surface of the toner particles is coated with oil.

[0072] The oil coverage rate of the pigment exposed on the surface of the toner particles (hereinafter also referred to as "oil coverage rate") is 20% or more, more preferably 25% or more, and even more preferably 30% or more. When the oil coating rate is 20% or higher, leakage of electricity from pigments exposed from toner particles is suppressed. This reduces the toner's chargeability, making it easier to prevent initial image fogging. Furthermore, from the viewpoint of contamination inside the developing machine, an oil coating rate of 60% or less is preferable, and 50% or less is more preferable.

[0073] The method for measuring the oil coverage rate (i.e., the oil coverage rate) is as follows: Prepare an aqueous surfactant solution containing 0.5% by mass of surfactant (Neugen ET-165, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) in deionized water. Place 50 mL of the aqueous surfactant solution into a 100 mL glass beaker, add 4 g of green toner, and stir with a magnetic stirrer at a rotation speed of 100 rpm for 5 minutes to prepare a toner dispersion. Prepare two of these toner dispersions. One of the toner dispersions is subjected to ultrasonic homogenizer (VCX750, Sonic and Material) with a probe inserted (1.0 cm from the probe tip to the bottom of the beaker), and ultrasonic waves at 20 W and 20 kHz are applied for 1 minute. The toner dispersion is centrifuged to separate the green toner particles, oil-treated silica particles, and other external additives by density, and the fraction containing oil-treated silica particles is collected. The fraction is dried, and a sample is taken from the toner to be measured. For the collected sample, a scanning electron microscope (SEM-EDX) equipped with an energy-dispersive X-ray fluorescence analyzer is used to observe a single toner particle at a magnification of 10,000x. Next, elemental mapping is performed on the surface of a single toner particle using an energy-dispersive X-ray fluorescence analyzer. In the elemental mapping on the surface of a single toner particle, let A be the area occupied by pigment-derived elements, and B be the area occupied by oil-derived elements within the area occupied by pigment-derived elements. The oil coverage rate is then calculated using the formula: Oil coverage rate = B / A × 100. This operation is then performed for 100 toner particles, and the arithmetic mean of the oil coverage rates is calculated. Here, the pigment-derived elements are, for example, nitrogen if the fluorescent organic pigment is an azomethine compound, and halogen if the non-fluorescent organic pigment is a halogenated phthalocyanine compound. In other words, when azomethine compounds and halogenated phthalocyanine compounds are used as pigments, the area occupied by nitrogen and halogen elements as pigment-derived elements is defined as area A. On the other hand, the element derived from the oil is, for example, silicon (Si) if the oil is silicone oil. In other words, when silicone oil is used as the oil, the area occupied by silicon (Si) as the element derived from the oil is defined as area B. The observation conditions for the scanning electron microscope are: acceleration voltage 15kV, emission current 20μA, and working distance (WD) 15mm. The analysis conditions using the energy-dispersive X-ray fluorescence spectrometer are the same as those for the scanning electron microscope, with a detection time of 60 minutes.

[0074] The oil used to coat the pigment may be one or more compounds selected from the group consisting of lubricating oils and fats. Specific examples of oils include silicone oil, paraffin oil, fluorine oil, and vegetable oil. One type of oil may be used, or multiple types may be used.

[0075] Examples of silicone oils include dimethyl silicone oil, methylphenyl silicone oil, chlorophenyl silicone oil, methyl hydrogen silicone oil, alkyl-modified silicone oil, fluorine-modified silicone oil, polyether-modified silicone oil, alcohol-modified silicone oil, amino-modified silicone oil, epoxy-modified silicone oil, epoxy-polyether-modified silicone oil, phenol-modified silicone oil, carboxyl-modified silicone oil, mercapto-modified silicone oil, acrylic-methacrylic-modified silicone oil, and α-methylstyrene-modified silicone oil. Examples of paraffin oils include liquid paraffin. Examples of fluorinated oils include fluorinated oil and fluorinated chloride oil. Examples of mineral oils include machine oil. Examples of vegetable oils include rapeseed oil and palm oil.

[0076] Among these oils, silicone oil is preferred from the viewpoint of suppressing electrical leakage from pigments exposed from toner particles and suppressing fogging of the initial image.

[0077] (Percentage of the surface area exposed to pigment on the toner particle surface) When observing the surface of toner particles, the proportion of the area occupied by pigment exposed on the surface of the toner particles is preferably 10% to 50% of the total surface area of ​​the toner particles, more preferably 15% to 45%, and even more preferably 20% to 40%.

[0078] Even if the area covered by pigment exposed on the toner particle surface is 50% or more, if the pigment exposed on the toner particle surface is covered by oil at the above oil coating rate, initial image blurring will be suppressed. When the area of ​​pigment exposed on the toner particle surface is 10% or less, excessive pigment exposure is suppressed, and the decrease in electrostatic charge is less likely to occur. As a result, initial image fogging is less likely to occur.

[0079] The percentage of the surface area exposed to pigment on the toner particle surface is calculated by determining the area A of the pigment-derived elements on a single toner particle, similar to the measurement of oil coverage. Using the observed toner particle area C and the area A of the pigment-derived elements, the percentage of the area occupied by pigment is calculated using the formula: Percentage of area occupied by pigment = A / C × 100. This process is then repeated for 100 toner particles to obtain the arithmetic mean of the percentage of area occupied by pigment.

[0080] (Average circularity of toner particles) The average circularity of the toner particles is preferably less than 0.940, more preferably 0.900 to 0.938, and even more preferably 0.910 to 0.935. Even when using toner particles with an average circularity of less than 0.940 and exhibiting irregular shapes, initial image fogging that occurs when toner is stored for a long period and then image is formed under high temperature and high humidity conditions is suppressed.

[0081] The average circularity of toner particles is determined by (circular equivalent perimeter) / (perimeter) [(perimeter of a circle with the same projected area as the particle image) / (perimeter of the particle projection image)]. Specifically, it is a value measured by the following method. First, the toner particles to be measured are collected by suction, a flattened flow is formed, and a strobe flash is instantaneously activated to capture a still image of the particles. This particle image is then analyzed using a flow-type particle image analyzer (Paasche analyzer PAS, manufactured by Hosokawa Micron Corporation). The number of samples used to determine the average circularity is 10,000. If the toner contains external additives, the toner (developer) to be measured is dispersed in water containing a surfactant, and then ultrasonic treatment is performed to obtain toner particles from which the external additives have been removed.

[0082] (Volume Average Particle Diameter of Toner Particles) The volume average particle diameter (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.

[0083] Note that various average particle diameters and various particle size distribution indexes of the toner particles are measured using a Coulter Multisizer II (manufactured by Beckman Coulter, Inc.) with ISOTON-II (manufactured by Beckman Coulter, Inc.) as the electrolytic solution. For the measurement, 0.5 mg or more and 50 mg or less of a measurement sample is added to 2 mL of a 5% aqueous solution of a surfactant (preferably sodium alkylbenzene sulfonate) as a dispersant. This mixture is then added to 100 mL or more and 150 mL or less of the electrolytic solution. The electrolytic solution in which the sample is suspended is subjected to dispersion treatment for 1 minute using an ultrasonic disperser, and then the particle size distribution of particles having a particle diameter in the range of 2 µm or more and 60 µm or less is measured with a Coulter Multisizer II using an aperture with an aperture diameter of 100 µm. Note that the number of particles to be sampled is 50,000. For particle size ranges (channels) divided based on the measured particle size distribution, cumulative distributions of volume and number are each drawn from the smaller diameter side. The particle diameter at 16% cumulative is defined as volume particle diameter D16v and number particle diameter D16p, the particle diameter at 50% cumulative is defined as volume average particle diameter D50v and cumulative number average particle diameter D50p, and the particle diameter at 84% cumulative is defined as volume particle diameter D84v and number particle diameter D84p. Using these values, the volume particle size distribution index (GSDv) is expressed as (D84v / D16v) 1 / 2 , and the number particle size distribution index (GSDp) is expressed as (D84p / D16p) 1 / 2 and calculated accordingly.

[0084] [External Additive] Examples of the external additive include inorganic particles. Examples of the inorganic particles include SiO2, TiO2, Al2O3, SrTiO3, CaTiO3, CuO, ZnO, SnO2, CeO2, Fe2O3, MgO, BaO, CaO, K2O, Na2O, ZrO2, CaO·SiO2, K2O·(TiO2) nExamples include Al2O3·2SiO2, CaCO3, MgCO3, BaSO4, and MgSO4.

[0085] Examples of external additives include resin particles (such as polystyrene, polymethyl methacrylate (PMMA), and melamine resin), and cleaning lubricants (for example, metal salts of higher fatty acids represented by zinc stearate, and particles of higher alcohols).

[0086] Among these, it is preferable to use oil-treated silica particles as the external additive. Applying oil-treated silica particles makes it easier to control the oil coating rate of the pigment exposed from the toner particles within the above range.

[0087] Oil-treated silica particles are silica particles that have been surface-treated with oil. The silica particles to be treated with oil can be any particles whose main component is silica, i.e., SiO2, and may be crystalline or amorphous. Furthermore, the silica particles may be manufactured using silicon compounds such as water glass or alkoxysilane as raw materials, or they may be particles obtained by crushing quartz. Specifically, examples of silica particles include sol-gel silica particles, aqueous colloidal silica particles, alcohol-based silica particles, fumed silica particles obtained by a gas-phase method, and fused silica particles.

[0088] Examples of oils used for surface treatment of silica particles include the same oils described above for coating the pigments exposed from the toner particles.

[0089] The content of oil-treated silica particles is preferably 0.5% by mass or more and 5.0% by mass or less relative to the toner particles. More preferably 0.7% by mass or more and 4.5% by mass or less, and even more preferably 0.8% by mass or more and 4.0% by mass or less.

[0090] When the content of oil-treated silica particles is between 0.5% by mass and 5.0% by mass, it becomes easier to control the oil coating rate of the pigment exposed from the toner particles within the above range. As a result, initial image fogging is more easily suppressed.

[0091] -Free oil volume- The amount of free oil in the oil-treated silica particles is preferably 5.0% by mass or more and 30.0% by mass or less, more preferably 8.0% by mass or more and 28.0% by mass or less, and even more preferably 10.0% by mass or more and 25.0% by mass or less.

[0092] When the amount of free oil in oil-treated silica particles is 5.0% by mass or more, the free oil migrates to the pigment exposed from the toner particles, making it easier to control the oil coating rate of the pigment within the above range. As a result, initial image fogging is more easily suppressed. When the amount of free oil in oil-treated silica particles is 30.0% by mass or less, excessive adhesion of free oil to the non-pigmented parts of the image forming apparatus components or toner particles is suppressed. As a result, the formation of toner aggregates is suppressed, and the occurrence of color streaks is reduced.

[0093] The amount of free oil is the ratio of the amount of free oil to the total amount of oil-treated silica particles. The amount of free oil is measured by the following method. Proton NMR (Nuclear Magnetic Resonance) measurements are performed on oil-treated silica particles using a JEOL AL-400 (magnetic field 9.4T (H nucleus 400MHz)). The sample, deuterated chloroform solvent, and TMS as a reference material are packed into a zirconia sample tube (5mm in diameter). With this sample tube set up, measurements are performed, for example, at a frequency of Δ87kHz / 400MHz (=Δ20ppm), a measurement temperature of 25℃, 16 integration cycles, and a resolution of 0.24Hz (32000 points). The amount of free oil is then calculated from the peak intensity derived from the free oil using a calibration curve. For example, if dimethyl silicone oil is used as the oil, NMR measurements are performed on untreated silica particles and dimethyl silicone oil (similarly varying the amounts in about 5 levels) to create a calibration curve between the amount of oil released and the NMR peak intensity. Then, the amount of released oil is calculated using the calibration curve.

[0094] To increase the amount of free oil in oil-treated silica particles, for example, the oil treatment can be performed multiple times. To decrease the amount of free oil in oil-treated silica particles, for example, the process of immersing in a solvent and then drying can be repeatedly performed.

[0095] -Volume-average particle size- The volume-average particle size of the oil-treated silica particles is preferably 15.0 nm to 200 nm, more preferably 40 nm to 150 nm, and even more preferably 80 nm to 120 nm.

[0096] When the volume-average particle size of the oil-treated silica particles is 15.0 nm or larger, the oil-treated silica particles come into contact more easily with the pigment exposed from the toner particles, making it easier to control the oil coating rate of the pigment within the above range. As a result, initial image fogging is more easily suppressed. When the volume-average particle size of the oil-treated silica particles is 200 nm or less, the oil-treated silica particles migrate to the components of the image forming apparatus, suppressing excessive adhesion of free oil to the components of the image forming apparatus. As a result, the formation of toner aggregates is suppressed, and the formation of color streaks is reduced.

[0097] The volume-average particle size of oil-treated silica particles is the value measured by the following method. One hundred primary particles of oil-treated silica were observed using a Scanning Electron Microscope (SEM). Next, the longest and shortest diameters of each primary particle were measured by image analysis, and the equivalent spherical diameter was calculated from the midpoint of these two values. The 50% diameter (D50v) at the cumulative frequency of the obtained equivalent spherical diameters based on volume was defined as the volume-average particle size of the oil-treated silica particles.

[0098] [Toner manufacturing method] The toner according to this embodiment is obtained by manufacturing toner particles and then adding an external additive to the toner particles.

[0099] Toner particles may be manufactured by either a dry method (e.g., kneading and grinding method) or a wet method (e.g., agglomeration and coalescence method, suspension polymerization method, dissolution and suspension method, etc.). There are no particular restrictions on these manufacturing methods, and known methods may be used. Among these, it is preferable to obtain toner particles by the kneading and grinding method. The kneaded and ground toner particles obtained by the kneading and grinding method have a low surfactant content, which reduces the water absorption rate of the toner to the above range. On the other hand, although the kneaded and ground toner particles have a lot of exposed pigment, the oil coating rate mentioned above covers the exposed pigment with oil, so even with kneaded and ground toner particles, initial image fogging is suppressed.

[0100] (Mixing and grinding method) When manufacturing toner particles by a kneading and grinding method, the following manufacturing method is preferred. A manufacturing method comprising a kneading step of obtaining a compound by kneading a binder resin and a pigment containing a fluorescent organic pigment, and a grinding step of grinding the obtained compound to obtain toner particles. If necessary, other steps may be included, such as a cooling step to cool the mixture formed by the mixing step.

[0101] The details of each step are explained below.

[0102] -Kneading process- The mixing process involves mixing a material containing a binder resin, a pigment, and other necessary additives (hereinafter sometimes referred to as the toner particle forming material). In the mixing process, it is desirable to add 0.5 to 5 parts by mass of an aqueous medium (for example, water such as distilled water or ion-exchanged water, alcohols, etc.) per 100 parts by mass of the toner particle forming material.

[0103] Examples of kneaders used in the mixing process include single-screw extruders and twin-screw extruders. Below, an example of a kneader having a feed screw section and two kneading sections will be explained with reference to a diagram, but it is not limited to this example.

[0104] Figure 1 is a diagram illustrating the state of the screw in an example of a screw extruder used in the kneading process in the toner manufacturing method of this embodiment. The screw extruder 11 consists of a barrel 12 equipped with a screw (not shown), an injection port 14 for injecting toner particle-forming material, which is the material for toner, into the barrel 12, a liquid addition port 16 for adding an aqueous medium to the toner particle-forming material in the barrel 12, and an outlet 18 for discharging the kneaded product formed by kneading the toner particle-forming material in the barrel 12.

[0105] The barrel 12 is divided into the following sections, in order from the end closest to the inlet 14: a feed screw section SA that transports the toner particle forming material injected from the inlet 14 to the kneading section NA; a kneading section NA for melting and kneading the toner particle forming material in a first kneading step; a feed screw section SB that transports the toner particle forming material melted and kneaded in the kneading section NA to the kneading section NB; a kneading section NB that melts and kneads the toner particle forming material in a second kneading step to form a kneaded product; and a feed screw section SC that transports the formed kneaded product to the discharge port 18.

[0106] Furthermore, the barrel 12 is equipped with different temperature control devices (not shown) for each block. That is, it is possible to control the temperature of each block from 12A to 12J to a different temperature. Figure 1 shows a state where the temperature of blocks 12A and 12B is controlled to t0°C, the temperature of blocks 12C to 12E is controlled to t1°C, and the temperature of blocks 12F to 12J is controlled to t2°C. As a result, the toner particle forming material in the kneading section NA is heated to t1°C, and the toner particle forming material in the kneading section NB is heated to t2°C.

[0107] When the toner particle forming material is supplied from the injection port 14 to the barrel 12, the feed screw SA sends the toner particle forming material to the kneading section NA. At this time, since the temperature of block 12C is set to t1℃, the toner particle forming material is heated and transformed into a molten state before being sent to the kneading section NA. Furthermore, since the temperatures of blocks 12D and 12E are also set to t1℃, the toner particle forming material is melted and kneaded at a temperature of t1℃ in the kneading section NA. The binder resin and release agent become molten in the kneading section NA and are sheared by the screw.

[0108] Next, the toner particle-forming material, which has undergone kneading in the kneading section NA, is sent to the kneading section NB by the feed screw section SB. Next, in the feed screw section SB, the aqueous medium is injected into the barrel 12 from the liquid injection port 16, thereby adding the aqueous medium to the toner particle forming material. Although Figure 1 shows the injection of the aqueous medium in the feed screw section SB, it is not limited to this configuration. The aqueous medium may also be injected in the kneading section NB, or in both the feed screw section SB and the kneading section NB. In other words, the position and injection location of the aqueous medium can be selected as needed.

[0109] As described above, when the aqueous medium is injected into the barrel 12 from the liquid injection port 16, the toner particle forming material in the barrel 12 mixes with the aqueous medium, the toner particle forming material is cooled by the latent heat of vaporization of the aqueous medium, and the temperature of the toner particle forming material is maintained. Finally, the kneaded material formed by melting and kneading in the kneading section NB is transported to the discharge port 18 by the feed screw section SC and discharged from the discharge port 18. As described above, the mixing process using the screw extruder 11 shown in Figure 1 is carried out.

[0110] -Cooling process- The cooling step is a step of cooling the kneaded product formed in the kneading step described above. In the cooling step, it is preferable to cool the product to 40°C or below at an average cooling rate of 4°C / sec or more from the temperature of the product at the end of the kneading step. If the cooling rate of the product is slow, the mixture (mixture of toner particle forming material) that was finely dispersed in the binder resin during the kneading step may recrystallize, and the dispersion diameter may increase. On the other hand, rapid cooling at the average cooling rate described above is preferable because it maintains the dispersion state immediately after the end of the kneading step. The average cooling rate described above refers to the average value of the rate at which the temperature of the product is cooled from the temperature of the product at the end of the kneading step (for example, t2°C when using the screw extruder 11 in Figure 1) to 40°C. Specific cooling methods in the cooling process include, for example, using rolling rolls and clamp-type cooling belts circulating cold water or brine. When cooling is performed by the above method, the cooling rate is determined by the speed of the rolling rolls, the brine flow rate, the amount of compound supplied, and the slab thickness of the compound during rolling. The slab thickness is preferably 1 to 3 mm.

[0111] -Grinding Process- The compound, cooled in the cooling process, is then pulverized in the grinding process to form toner particles. In the grinding process, for example, mechanical grinders, jet grinders, etc., are used.

[0112] -Classification process- The particles obtained in the grinding process may be classified in a classification process if necessary to obtain toner particles with a volume-average particle size within the desired range. In the classification process, conventional centrifugal classifiers, inertial classifiers, etc., are used to remove fine powder (particles smaller than the desired particle size range) and coarse powder (particles larger than the desired particle size range).

[0113] -External addition process- The resulting toner particles are then coated with an external additive (e.g., oil-treated silica particles). This process is carried out in stages using, for example, a V-type blender, a Henschel mixer, or a Reidige mixer.

[0114] -Sieving process- A sieving step may be added after the above external additive step, if necessary. Specific sieving methods include, for example, a gyro shifter, a vibrating sieving machine, or a wind sieving machine. Sieving removes coarse powder of the external additive, suppressing the occurrence of streaks on the photoreceptor and soiling inside the device.

[0115] <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 obtained by mixing the toner and a carrier.

[0116] 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.

[0117] Examples of magnetic powders include magnetic metals such as iron, nickel, and cobalt, and magnetic oxides such as ferrite and magnetite. In particular, magnetite and ferrite are preferred as magnetic powders. The magnetic powder may also be used as particles in which the magnetic powder is dispersed in a resin.

[0118] Examples of coating resins and matrix resins include styrene-(meth)acrylic acid resin; polyolefin resins such as polyethylene resin and polypropylene resin; polyvinyl or polyvinylidene resins such as polystyrene, (meth)acrylic resin, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinylcarbazole, polyvinyl ether, and polyvinyl ketone; vinyl chloride-vinyl acetate copolymer; straight silicone resins or modified products thereof consisting of organosiloxane bonds; fluororesins such as polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, and polychlorotrifluoroethylene; polyester; polyurethane; polycarbonate; amino resins such as urea-formaldehyde resin; epoxy resin; and the like. The coating resin and matrix resin preferably contain a (meth)acrylic resin, and more preferably contain a (meth)acrylic resin having an alicyclic structure. The coating resin and matrix resin may also contain a nitrogen-containing (meth)acrylic resin. It is more preferable that the (meth)acrylic resin is present in an amount of 50% by mass or more relative to the total mass of the resin, and even more preferable that the (meth)acrylic resin is present in an amount of 80% by mass or more relative to the total mass of the resin. In particular, the coating resin and the matrix resin preferably contain an alicyclic (meth)acrylic resin as the (meth)acrylic resin. 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 dioxide, zinc oxide, tin oxide, barium sulfate, aluminum borate, and potassium titanate. Other additives include metal oxide particles such as silica, titanium oxide, zinc oxide, and tin oxide; metal compound particles such as barium sulfate, aluminum borate, and potassium titanate; and metal particles such as gold, silver, and copper. Among these, silica particles are preferred. The above particles are preferably contained in an amount of 10% to 60% by mass relative to the total mass of the resin layer.

[0119] 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.

[0120] 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.

[0121] <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 device for charging the surface of the image holder, an electrostatic image forming apparatus for forming an electrostatic image on the charged surface of the image holder, a developing apparatus 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 apparatus for transferring the toner image formed on the surface of the image holder to the surface of a recording medium, and a fixing apparatus for fixing the toner image transferred to the surface of the recording medium. The electrostatic image developer according to this embodiment is used as the electrostatic image developer.

[0122] 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 the image holder; a developing step of developing the electrostatic image formed on the surface of the 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 the image holder to the surface of a recording medium; and a fixing step of fixing the toner image transferred to the surface of the recording medium.

[0123] 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 intermediate transfer body to the surface of an intermediate transfer body and second transfers the toner image transferred to the surface of the intermediate transfer body to the surface of a recording medium, an apparatus equipped with a cleaning device that cleans the surface of the image holder after the transfer of the toner image and before charging, or an apparatus equipped with a static elimination device 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 apparatus may include, for example, an intermediate transfer body on which a toner image is transferred; a primary transfer apparatus that first transfers the toner image formed on the surface of the image holder to the surface of the intermediate transfer body; and a secondary transfer apparatus that secondarily transfers the toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium.

[0124] In the image forming apparatus according to this embodiment, for example, the part including the developing device 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 device containing the electrostatic image developer according to this embodiment is preferably used.

[0125] 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.

[0126] In the following description, a six-unit tandem image forming apparatus, in which six image forming units are arranged in a row, will be described as an example of an image forming apparatus according to this embodiment. The tandem image forming apparatus is not limited to this, and may also be a five-unit tandem image forming apparatus, a four-unit tandem image forming apparatus, a four-unit tandem image forming apparatus, and so on.

[0127] Figure 2 is a schematic diagram showing an image forming apparatus according to this embodiment, and is a diagram showing an image forming apparatus with a 6-series tandem system and an intermediate transfer system. The image forming apparatus shown in Figure 2 includes first to sixth image forming units 10P, 10Y, 10M, 10C, 10K, and 10G, which are electrophotographic image forming units that output images of pink (P), yellow (Y), magenta (M), cyan (C), black (K), and green (G) based on color-separated image data. These image forming units (hereinafter sometimes simply referred to as "units") 10P, 10Y, 10M, 10C, 10K, and 10G are arranged side by side at predetermined distances from each other in the horizontal direction. These units 10P, 10Y, 10M, 10C, 10K, and 10G may also be process cartridges that can be attached to and detached from the image forming apparatus.

[0128] An intermediate transfer belt (an example of an intermediate transfer body) 20 extends from below each unit 10P, 10Y, 10M, 10C, 10K, and 10G through each unit. The intermediate transfer belt 20 is wound around a drive roll 22, a support roll 23, and an opposing roll 24 that 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 10P to the sixth unit 10G. An intermediate transfer body cleaning device 21 is provided on the image holding surface side of the intermediate transfer belt 20, opposite the drive roll 22.

[0129] Each unit, 10P, 10Y, 10M, 10C, 10K, and 10G, is supplied with pink, yellow, magenta, cyan, black, and green toners, respectively, contained in toner cartridges 8P, 8Y, 8M, 8C, 8K, and 8G.

[0130] Since the first to sixth units 10P, 10Y, 10M, 10C, 10K, and 10G have equivalent configurations and operations, the sixth unit 10G, which forms the green image, will be described as representative here. For example, the toner according to this embodiment is used as the toner for forming a green image.

[0131] The sixth unit 10G has a photoreceptor 1G that acts as an image holder. Around the photoreceptor 1G are, in order, a charging roll (an example of a charging device) 2G that charges the surface of the photoreceptor 1G to a predetermined potential, an exposure device (an example of an electrostatic image forming device) 3G that exposes the charged surface with a laser beam based on a color-separated image signal to form an electrostatic image, a developing device (an example of a developing device) 4G that supplies toner to the electrostatic image to develop the electrostatic image, a primary transfer roll (an example of a primary transfer device) 5G that transfers the developed toner image onto an intermediate transfer belt 20, and a photoreceptor cleaning device (an example of a cleaning device) 6G that removes toner remaining on the surface of the photoreceptor 1G after primary transfer.

[0132] The primary transfer roll 5G is positioned inside the intermediate transfer belt 20, facing the photoreceptor 1G. Each primary transfer roll 5Y, 5P, 5M, 5C, 5G, and 5K of each unit is connected to a bias power supply (not shown) that applies the primary transfer bias. Each bias power supply is applied to each primary transfer roll under the control of a control unit (not shown). Change the value of the transcription bias.

[0133] The following describes the process of forming a green image in the 6th unit 10G. First, prior to operation, the surface of the photoreceptor 1G is charged to a potential of -600V to -800V by the charging roll 2G. Photoreceptor 1G is conductive (for example, volume resistivity of 1 × 10 at 20°C). -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, the resistivity of the irradiated area changes. Therefore, a laser beam is irradiated from the exposure device 3G onto the surface of the charged photoreceptor 1G according to green image data sent from a control unit (not shown). As a result, an electrostatic image of the green image pattern is formed on the surface of the photoreceptor 1G.

[0134] An electrostatic image is an image formed on the surface of the photoreceptor 1G due to electrostatic charge. It is a so-called negative latent image formed when the resistivity of the irradiated portion of the photoreceptor decreases due to the laser beam from the exposure device 3G, causing the charged material on the surface of the photoreceptor 1G to flow, while the charge remains in the portion not irradiated by the laser beam. The electrostatic charge image formed on the photoreceptor 1G rotates to a predetermined development position as the photoreceptor 1G moves. At this development position, the electrostatic charge image on the photoreceptor 1G is developed as a toner image by the developing device 4G and made visible.

[0135] The developing unit 4G contains, for example, an electrostatic image developer including at least green toner and a carrier. The green toner is triboelectrically charged by being agitated inside the developing unit 4G 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 1G. As the surface of the photoreceptor 1G passes through the developing unit 4G, the green toner electrostatically adheres to the discharged latent image on the surface of the photoreceptor 1G, and the latent image is developed by the green toner. The photoreceptor 1G, on which the green toner image has been formed, continues to move at a predetermined speed, and the toner image developed on the photoreceptor 1G is transported to a predetermined primary transfer position.

[0136] When the green toner image on the photoreceptor 1G is transported to the primary transfer position, a primary transfer bias is applied to the primary transfer roll 5G, and an electrostatic force acts on the toner image from the photoreceptor 1G to the primary transfer roll 5G, transferring the toner image on the photoreceptor 1G 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 10G, it is controlled by a control unit (not shown) to, for example, +10 μA.

[0137] After transferring the toner image to the intermediate transfer belt 20, the photoreceptor 1G continues to rotate and comes into contact with the cleaning blades of the photoreceptor cleaning device 6G. Any toner remaining on the photoreceptor 1G is removed and collected by the photoreceptor cleaning device 6G.

[0138] The intermediate transfer belt 20 is sequentially transported through the first to sixth image forming units 10P, 10Y, 10M, 10C, 10K, and 10G, and the toner images of each color are superimposed and transferred in multiple layers.

[0139] The intermediate transfer belt 20, on which six-color toner images have been multiple-transferred through the first to sixth units, proceeds to a secondary transfer section consisting of the intermediate transfer belt 20, a counter roll 24 in contact with the inner surface of the intermediate transfer belt, and a secondary transfer roll (an example of a secondary transfer device) 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 counter roll 24. The transfer bias is negative (-) polarity, the same as the toner's polarity (-). An electrostatic force acts on the toner image from the intermediate transfer belt 20 toward the recording paper P, and the toner image on the intermediate transfer belt 20 is transferred onto the recording paper P. The secondary transfer bias at this time is determined according to the resistance detected by a resistance detection device (not shown) that detects the resistance of the secondary transfer section, and is voltage-controlled.

[0140] After transferring the toner image to the recording paper P, the intermediate transfer belt 20 continues to move and comes into contact with the cleaning blades of the intermediate transfer body cleaning device 21. Any toner remaining on the intermediate transfer belt 20 is removed and collected by the intermediate transfer body cleaning device 21.

[0141] The recording paper P onto which the toner image has been transferred is fed to the contact area (nip area) of a pair of fixing rolls in a fixing device (an example of a fixing device) 28, where the toner image is fixed onto the recording paper P, and a fixed image is formed.

[0142] 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.

[0143] 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.

[0144] <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 is equipped with a developing device that develops the electrostatic image formed on the surface of an 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.

[0145] 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 device selected from, for example, an image holder, a charging device, an electrostatic image forming device, and a transfer device.

[0146] An example of a process cartridge according to this embodiment is shown below, but it is not limited to this example. In the following description, only the main parts shown in the figure will be described, and other parts will be omitted from the description.

[0147] Figure 3 is a schematic diagram showing the process cartridge according to this embodiment. The process cartridge 200 shown in Figure 3 is constructed by integrally holding a photoreceptor 107 (an example of an image holder), a charging roll 108 (an example of a charging device), a developing device 111 (an example of a developing device), and a photoreceptor cleaning device 113 (an example of a cleaning device) provided around the photoreceptor 107, using a housing 117 equipped with a mounting rail 116 and an opening 118 for exposure, and is then formed into a cartridge. In Figure 3, 109 is an exposure apparatus (an example of an electrostatic image forming apparatus), 112 is a transfer apparatus (an example of a transfer apparatus), 115 is a fixing apparatus (an example of a fixing apparatus), and 300 is recording paper (an example of a recording medium).

[0148] Next, the toner cartridge according to this embodiment will be described. The toner cartridge according to this embodiment contains the green toner according to this embodiment, This is a toner cartridge that is attached to and detached from an image forming apparatus. The toner cartridge contains replenishment toner for supply to the developing apparatus located within the image forming apparatus.

[0149] The image forming apparatus shown in Figure 2 is configured to allow the attachment and detachment of toner cartridges 8P, 8Y, 8M, 8C, 8K, and 8G. The developing units 4P, 4Y, 4M, 4C, 4K, and 4G are connected to toner cartridges corresponding to their respective colors by toner supply pipes (not shown). When the amount of toner contained in a toner cartridge becomes low, the toner cartridge is replaced. An example of a toner cartridge according to this embodiment is toner cartridge 8G, which contains the toner according to this embodiment. Toner cartridges 8P, 8Y, 8M, 8C, and 8K contain pink, yellow, magenta, cyan, and black toners, respectively. [Examples]

[0150] The embodiments of the invention will be described in detail below with reference to examples, but the embodiments of the invention are not limited to these examples. In the following explanation, unless otherwise specified, "parts" and "%" refer to mass. Synthesis, processing, and manufacturing were carried out at room temperature (25°C ± 3°C) unless otherwise specified.

[0151] <Preparation of polyester resin (1)> Terephthalic acid: 30 moles Fumaric acid: 70 moles • Bisphenol A ethylene oxide adduct: 5 moles • Bisphenol A propylene oxide adduct: 95 moles The above materials are placed in a flask equipped with an upper stirrer, a nitrogen inlet tube, a temperature sensor, and a rectification column, and the temperature is raised to 220°C over 1 hour. After raising the temperature, 1 part titanium tetraethoxide is added to 100 parts of the above materials. The temperature is raised to 230°C over 30 minutes while distilling off the water produced, and the dehydration condensation reaction is continued at this temperature for 1 hour, after which the reactants are cooled. In this way, a polyester resin (1) with a weight-average molecular weight of 18,000 and a glass transition temperature of 60°C is obtained.

[0152] <Preparation of colorant-dispersed particles (1)> • Fluorescent yellow pigment (CI Pigment Yellow 101 (Radiant Color, Radglo VSF-0-01, emission peak wavelength 520nm)): 70 parts • Anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK): 30 parts (solid content concentration 20%) The above components were mixed and ground to 300 nm using a continuous key mill (KMC-3) to obtain colorant-dispersed particles (1).

[0153] <Preparation of colorant-dispersed particles (2)> • Non-fluorescent green pigment (CI Pigment Green 36 (manufactured by Toyo Color Co., Ltd., LIONOL GREEN 8624, reflectance peak wavelength 510nm)): 70 parts • Anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK): 30 parts (solid content concentration 20%) The above components are mixed and ground to 150 nm using a continuous key mill (KMC-3) to obtain colorant-dispersed particles (2).

[0154] <Preparation of colorant-dispersed particles (3)> • Fluorescent yellow pigment (Radiant Color, Radglo VSF-0-05, emission peak wavelength 519nm): 70 parts • Anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK): 30 parts (solid content concentration 20%) The above components are mixed and ground to 300 nm using a continuous key mill (KMC-3) to obtain colorant-dispersed particles (3).

[0155] <Preparation of colorant-dispersed particles (4)> • Fluorescent yellow pigment (CI Pigment Yellow 101 (Radiant Color, Radglo VSF-0-01, emission peak wavelength 520nm)): 70 parts • Anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK): 30 parts (solid content concentration 20%) The above components were mixed and ground to 100 nm using a continuous key mill (KMC-3) to obtain colorant-dispersed particles (4).

[0156] <Preparation of colorant-dispersed particles (5)> • Fluorescent yellow pigment (CI Pigment Yellow 101 (Radiant Color, Radglo VSF-0-01, emission peak wavelength 520nm)): 70 parts • Anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK): 30 parts (solid content concentration 20%) The above components were mixed and ground to 150 nm using a continuous key mill (KMC-3) to obtain colorant-dispersed particles (5).

[0157] <Preparation of colorant-dispersed particles (6)> • Fluorescent yellow pigment (CI Pigment Yellow 101 (Radiant Color, Radglo VSF-0-01, emission peak wavelength 520nm)): 70 parts • Anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK): 30 parts (solid content concentration 20%) The above components were mixed and ground to 450 nm using a continuous key mill (KMC-3) to obtain colorant-dispersed particles (6).

[0158] <Preparation of colorant-dispersed particles (7)> • Fluorescent yellow pigment (CI Pigment Yellow 101 (Radiant Color, Radglo VSF-0-01, emission peak wavelength 520nm)): 70 parts • Anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK): 30 parts (solid content concentration 20%) The above components were mixed and ground to 500 nm using a continuous key mill (KMC-3) to obtain colorant-dispersed particles (7).

[0159] <Preparation of oil-treated silica particles (1)> SiCl4, hydrogen gas, and oxygen gas are mixed in the mixing chamber of a combustion burner and then burned at a temperature between 1000°C and 3000°C. Silica particles are obtained by extracting silica powder from the gas after combustion. At this time, silica particles (R1) with a volume-average particle size (D50v) of 100 nm are obtained by setting the molar ratio of hydrogen gas to oxygen gas to 1.35:1. Place 100 parts of silica particles (R1) and 500 parts of ethanol into an evaporator and adjust the temperature. The mixture is stirred for 15 minutes while maintaining a temperature of 40°C. Next, 10 parts dimethyl silicone oil is added to 100 parts silica particles (R1) and stirred for 15 minutes. Then, 15 parts dimethyl silicone oil is added to 100 parts silica particles (R1) and stirred for another 15 minutes. Finally, the temperature is raised to 90°C and the ethanol is dried under reduced pressure. After that, the treated material is removed and further vacuum-dried at 120°C for 30 minutes to obtain oil-treated silica particles (1) with a volume-average particle size (D50v) of 100 nm and a free oil content of 20% by mass.

[0160] <Preparation of oil-treated silica particles (2)> Oil-treated silica particles (2) are obtained in the same manner as oil-treated silica particles (1), except that in the preparation of oil-treated silica particles (1), dimethyl silicone oil is added in an amount of 10 to 16 parts per 100 parts of silica particles and stirred for 15 minutes, and then dimethyl silicone oil is added again in an amount of 15 to 18 parts per 100 parts of silica particles.

[0161] <Preparation of oil-treated silica particles (3)> SiCl4, hydrogen gas, and oxygen gas are mixed in the mixing chamber of a combustion burner and then burned at a temperature between 1000°C and 3000°C. Silica particles are obtained by extracting silica powder from the gas after combustion. At this time, silica particles (R2) with a volume-average particle size (D50v) of 18 nm are obtained by setting the molar ratio of hydrogen gas to oxygen gas to 1.15:1. Place 100 parts of silica particles (R2) and 500 parts of ethanol into an evaporator and set the temperature The mixture is stirred for 15 minutes while maintaining a temperature of 40°C. Next, 10 parts dimethyl silicone oil is added to 100 parts silica particles (R2) and stirred for 15 minutes. Then, 15 parts dimethyl silicone oil is added to another 100 parts silica particles (R2) and stirred for another 15 minutes. Finally, the temperature is raised to 90°C and the ethanol is dried under reduced pressure. After that, the treated material is removed and vacuum-dried at 120°C for 30 minutes to obtain oil-treated silica particles (3) with a volume-average particle size (D50v) of 18 nm and a free oil content of 23% by mass.

[0162] <Preparation of oil-treated silica particles (4)> SiCl4, hydrogen gas, and oxygen gas are mixed in the mixing chamber of a combustion burner and then burned at a temperature between 1000°C and 3000°C. Silica particles are obtained by extracting silica powder from the gas after combustion. At this time, silica particles (R3) with a volume-average particle size (D50v) of 194 nm are obtained by using a molar ratio of hydrogen gas to oxygen gas of 1.45:1. Place 100 parts of silica particles (R3) and 500 parts of ethanol into an evaporator and set the temperature The mixture is stirred for 15 minutes while maintaining a temperature of 40°C. Next, 10 parts dimethyl silicone oil is added to 100 parts silica particles (R3) and stirred for 15 minutes. Then, 15 parts dimethyl silicone oil is added to another 100 parts silica particles (R3) and stirred for another 15 minutes. Finally, the temperature is raised to 90°C and the ethanol is dried under reduced pressure. After that, the treated material is removed and vacuum-dried at 120°C for 30 minutes to obtain oil-treated silica particles (4) with a volume-average particle size (D50v) of 194 nm and a free oil content of 13% by mass.

[0163] <Preparation of oil-treated silica particles (5)> In the preparation of oil-treated silica particles (1), dimethyl silicone oil is added in the same manner as for oil-treated silica particles (1), except that the amount of dimethyl silicone oil is changed from 10 parts to 5 parts per 100 parts of silica particles (R1) and stirred for 15 minutes, and then dimethyl silicone oil is added again in the same manner as for oil-treated silica particles (1), except that the amount of dimethyl silicone oil is changed from 15 parts to 5 parts per 100 parts of silica particles.

[0164] <Preparation of oil-treated silica particles (6)> In the preparation of oil-treated silica particles (1), dimethyl silicone oil is added in the same manner as for oil-treated silica particles (1), except that the amount of dimethyl silicone oil is changed from 10 parts to 8 parts per 100 parts of silica particles (R1) and stirred for 15 minutes, and then dimethyl silicone oil is added again in the same manner as for oil-treated silica particles (1), except that the amount of dimethyl silicone oil is changed from 15 parts to 10 parts per 100 parts of silica particles.

[0165] <Preparation of oil-treated silica particles (7)> Oil-treated silica particles (7) are obtained in the same manner as oil-treated silica particles (1), except that in the preparation of oil-treated silica particles (1), dimethyl silicone oil is added in an amount of 10 to 18 parts per 100 parts of silica particles (R1) and stirred for 15 minutes, and then dimethyl silicone oil is added again in an amount of 15 to 20 parts per 100 parts of silica particles.

[0166] <Preparation of oil-treated silica particles (8)> SiCl4, hydrogen gas, and oxygen gas are mixed in the mixing chamber of a combustion burner and then burned at a temperature between 1000°C and 3000°C. Silica particles are obtained by extracting silica powder from the gas after combustion. At this time, silica particles (R4) with a volume-average particle size (D50v) of 13 nm are obtained by setting the molar ratio of hydrogen gas to oxygen gas to 1.05:1. Oil-treated silica particles (8) are obtained in the same manner as oil-treated silica particles (1), except that silica particles (R1) are replaced with silica particles (R4).

[0167] <Preparation of oil-treated silica particles (9)> SiCl4, hydrogen gas, and oxygen gas are mixed in the mixing chamber of a combustion burner and then burned at a temperature between 1000°C and 3000°C. Silica particles are obtained by extracting silica powder from the gas after combustion. At this time, silica particles (R5) with a volume-average particle size (D50v) of 212 nm are obtained by using a molar ratio of 1.55:1 between hydrogen gas and oxygen gas. Oil-treated silica particles (9) are obtained in the same manner as oil-treated silica particles (1), except that silica particles (R1) are replaced with silica particles (R5).

[0168] <Preparation of oil-treated silica particles (10)> In the preparation of oil-treated silica particles (1), dimethyl silicone oil is added in the same manner as for oil-treated silica particles (1), except that the amount of dimethyl silicone oil is changed from 10 parts to 3 parts per 100 parts of silica particles (R1) and stirred for 15 minutes, and then dimethyl silicone oil is added again in the same manner as for oil-treated silica particles (1), except that the amount of dimethyl silicone oil is changed from 15 parts to 5 parts per 100 parts of silica particles.

[0169] <Preparation of oil-treated silica particles (11)> Oil-treated silica particles (11) are obtained in the same manner as oil-treated silica particles (1), except that the amount of dimethyl silicone oil is changed from 10 parts to 15 parts per 100 parts of silica particles (R1) and stirred for 15 minutes, and then the amount of dimethyl silicone oil is changed again from 15 parts to 18 parts per 100 parts of silica particles (R1) and added.

[0170] <Example 1> (Preparation of toner particles (1)) • Polyester resin (1): 560 parts • Colorant dispersed particles (1): 70 parts • Colorant dispersed particles (2): 30 parts Paraffin wax (manufactured by Nippon Seiro Co., Ltd., HNP-9): 30 units Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd.: Neogen RK, 20%): 12 parts The above raw materials are pre-mixed in a Henschel mixer, and then kneaded under the following conditions in a twin-screw extruder having a screw configuration of feed section-kneading section-feed section-kneading section-feed section. The screw rotation speed is set to 500 rpm (revolutions per minute), and the feed rate is set to 80 kg. In the intermediate feed section described above, an aqueous medium is added, consisting of 1.5 parts of distilled water and 0.02 parts of anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK) per 100 parts of raw material. The kneaded material is slowly cooled at 10 degrees Celsius / second or less using a rolling roll that passes through brine and a cooling belt in a slab-clamping type with cold water cooling. After coarse grinding with a pin mill, it is crushed with a hammer mill. Subsequently, it is ground using a pulverizer (AFG400) built into a coarse powder pulverizer classifier to obtain toner particles (1) of the desired particle size.

[0171] For every 100 parts of the resulting toner particles (1), 1.5 parts of oil-treated silica particles (1) and 1.0 part of hydrophobic titanium oxide (manufactured by Nippon Aerosil Co., Ltd., T805) are mixed and blended using a sample mill at 10,000 rpm (revolutions per minute) for 30 seconds. Then, the mixture is sieved using a vibrating sieve with a mesh size of 45 μm to obtain toner (1).

[0172] <Example 2> Toner particles and toner are obtained in the same manner as in Example 1, except that 20 parts of colorant-dispersed particles (1) and 50 parts of colorant-dispersed particles (2) are used for the preparation of toner particles (1).

[0173] <Example 3> Except for preparing the toner particles (1) in Example 1, which uses 35 parts of colorant-dispersed particles (1) and 8 parts of colorant-dispersed particles (2), toner particles and toner are obtained in the same manner as in Example 1. <Example 4> Toner particles and toner are obtained in the same manner as in Example 1, except that 130 parts of colorant-dispersed particles (1) and 60 parts of colorant-dispersed particles (2) are used for the preparation of toner particles (1).

[0174] <Example 5> Toner particles (1) and toner are obtained in the same manner as in Example 1, except that 160 parts of colorant-dispersed particles (1) are used for the preparation of toner particles (1).

[0175] <Example 6> In the preparation of toner particles (1), the amount of anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd.: Neogen RK, 20%) used for pre-mixing with a Henschel mixer was changed from 12 parts to 24 parts, and further In the intermediate feed section, toner particles and toner are obtained in the same manner as in Example 1, except that the amount of anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK) is changed from 0.02 parts to 0.04 parts per 100 parts of raw material supply.

[0176] <Example 7> Toner particles (1) are obtained in the same manner as in Example 1, except that 40 parts of the above-mentioned colorant-dispersed particles (4) are used. Toner is obtained in the same manner as in Example 1, except that the toner particles obtained and oil-treated silica particles (2) are used in the preparation of toner (1).

[0177] <Example 8> Toner particles (1) are prepared in the same manner as in Example 1, except that 50 parts of colorant-dispersed particles (4) are used. In the preparation of toner (1), toner is obtained in the same manner as in Example 1, except that the toner particles obtained and oil-treated silica particles (3) are used.

[0178] <Example 9> Toner particles (1) are prepared in the same manner as in Example 1, except that 150 parts of colorant-dispersed particles (4) are used. In the preparation of toner (1), toner is obtained in the same manner as in Example 1, except that the toner particles obtained and oil-treated silica particles (4) are used.

[0179] <Example 10> Toner particles (1) are prepared in the same manner as in Example 1, except that 150 parts of colorant-dispersed particles (5) are used. Toner (9) is obtained in the same manner as in Example 1, except that the toner particles obtained in the preparation of toner (1) are used.

[0180] <Example 11> Toner (1) is prepared in the same manner as in Example 1, except that the oil-treated silica particles (1) are reduced from 1.5 parts to 0.3 parts.

[0181] <Example 12> Toner (1) is prepared in the same manner as in Example 1, except that the oil-treated silica particles (1) are reduced from 1.5 parts to 0.6 parts.

[0182] <Example 13> Toner (1) is prepared in the same manner as in Example 1, except that the amount of oil-treated silica particles (1) is reduced from 1.5 parts to 4.8 parts.

[0183] <Example 14> Toner (1) is prepared in the same manner as in Example 1, except that the amount of oil-treated silica particles (1) is reduced from 1.5 parts to 5.4 parts.

[0184] <Example 15> Toner (1) is prepared in the same manner as in Example 1, except that oil-treated silica particles (5) (1.5 parts) are used.

[0185] <Example 16> Toner (1) is prepared in the same manner as in Example 1, except that oil-treated silica particles (6) (1.5 parts) are used. <Example 17> Except for using oil-treated silica particles (2) (1.5 parts) in the preparation of toner (1), toner particles and toner are obtained in the same manner as in Example 1.

[0186] <Example 18> Toner is obtained in the same manner as in Example 1, except that the oil-treated silica particles (7) (1.5 parts) obtained in the preparation of toner (1) are used.

[0187] <Example 19> In the preparation of toner (1), a toner is obtained in the same manner as in Example 1, except that 1.5 parts of oil-treated silica particles (8) are used.

[0188] <Example 20> In the preparation of toner (1), a toner is obtained in the same manner as in Example 1, except that 1.5 parts of oil-treated silica particles (3) are used.

[0189] <Example 21> In the preparation of toner (1), a toner is obtained in the same manner as in Example 1, except that 1.5 parts of oil-treated silica particles (4) are used.

[0190] <Example 22> In the preparation of toner (1), a toner is obtained in the same manner as in Example 1, except that 1.5 parts of oil-treated silica particles (9) are used.

[0191] <Example 23> In the preparation of toner (1), a toner is obtained in the same manner as in Example 1, except that 1.5 parts of oil-treated silica particles (10) are used.

[0192] <Example 24> In the preparation of toner (1), a toner is obtained in the same manner as in Example 1, except that oil-treated silica particles (11) are used.

[0193] <Example 25> In the preparation of toner particles (1), toner particles are obtained in the same manner as in Example 1, except that 100 parts of colorant-dispersed particles (1) and 0 parts of colorant-dispersed particles (2) are used. In the preparation of toner (1), a toner is obtained in the same manner as in Example 1, except that the obtained toner particles and oil-treated silica particles (1) are used.

[0194] <Example 26> In the preparation of toner particles (1), toner particles are obtained in the same manner as in Example 1, except that colorant-dispersed particles (3) are used in place of colorant-dispersed particles (1). In the preparation of toner (1), toner is obtained in the same manner as in Example 1, except that the toner particles and oil-treated silica particles (1) obtained are used.

[0195] <Comparative Example 1> In the preparation of toner (1), toner is obtained in the same manner as in Example 1, except that 1.0 part of oil-treated silica particles (1) is added.

[0196] <Comparative Example 2> Toner is obtained in the same manner as in Example 1, except that oil-treated silica particles (1) are not added in the preparation of toner (1), and 1.5 parts of untreated silica particles that have not been treated with dimethyl silicone oil are added in the preparation of oil-treated silica particles (1).

[0197] <Comparative Example 3> Toner particles (1) are prepared in the same manner as in Example 1, except that 30 parts of colorant-dispersed particles (1) and 8 parts of (2) are used. Toner is obtained in the same manner as in Example 1, except that the toner particles obtained in the preparation of toner (1) are used.

[0198] <Comparative Example 4> Toner particles (1) are prepared in the same manner as in Example 1, except that 140 parts of colorant-dispersed particles (1) and 70 parts of colorant-dispersed particles (2) are used. Toner is obtained in the same manner as in Example 1, except that the toner particles obtained in the preparation of toner (1) are used.

[0199] <Comparative Example 5> Toner particles are obtained by the method described in Japanese Patent Publication No. 2016-224339 as follows. Toner is obtained in the same manner as in Example 1, except that the toner particles obtained in the preparation of toner (1) are used.

[0200] <Preparation of polyester resin particle dispersion> [Preparation of polyester resin particle dispersion (1)] • Bisphenol A ethylene oxide 2.2 molar adduct: 40 molar parts • Bisphenol A propylene oxide 2.2 molar adduct: 60 molar parts Dimethyl terephthalate: 60 moles Dimethyl fumarate: 15 moles • Dodecenyl succinic anhydride: 20 moles • Trimellitus anhydride: 5 moles In a reaction vessel equipped with a stirrer, thermometer, condenser, and nitrogen gas inlet tube, all monomers except fumaric acid and trimellitic anhydride, along with 0.25 parts of tin dioctanoate per 100 parts of the total monomers, are added. The mixture is reacted at 235°C for 6 hours under a nitrogen gas stream, then the temperature is lowered to 200°C, and fumaric acid and trimellitic anhydride are added and reacted for 1 hour. The temperature is raised to 220°C over 5 hours, and polymerization is carried out under a pressure of 10 kPa until the desired molecular weight is obtained, yielding a pale yellow transparent polyester resin (1). The polyester resin (2) has a weight-average molecular weight of 35,000, a number-average molecular weight of 8,000, and a glass transition temperature of 59°C.

[0201] Next, the resulting polyester resin (2) is dispersed using a disperser modified from a Cavitron CD1010 (manufactured by Eurotech Co., Ltd.) to a high-temperature, high-pressure type. The composition ratio is 80% deionized water and 20% polyester resin, the pH is adjusted to 8.5 with ammonia, the rotor rotation speed is 60 Hz, and the pressure is 5 kg / cm². 2 The Cavitron was operated under the conditions of heating to 140°C using a heat exchanger to obtain a polyester resin dispersion (solid content 20%). The volume-average particle size of the resin particles in this dispersion is 130 nm. Ion-exchanged water is added to the dispersion to adjust the solid content to 20%, and this is designated as polyester resin particle dispersion (1).

[0202] [Preparation of polyester resin particle dispersion (2)] • 1,10-Dodecanedioic acid: 50 moles • 1,9-nonanediol: 50 moles The monomer is placed in a reaction vessel equipped with a stirrer, thermometer, condenser, and nitrogen gas inlet tube. After replacing the reaction vessel with dry nitrogen gas, 0.25 parts titanium tetrabutoxide is added per 100 parts of the monomer. The mixture is stirred and reacted at 170°C for 3 hours under a nitrogen gas stream. The temperature is then further increased to 210°C over 1 hour, the pressure inside the reaction vessel is reduced to 3 kPa, and the mixture is stirred and reacted under reduced pressure for 13 hours to obtain polyester resin (2). The polyester resin (3) has a weight-average molecular weight of 25,000, a number-average molecular weight of 10,500, an acid value of 10.1 mgKOH / g, and a melting temperature of 73.6°C determined by DSC. Next, the obtained polyester resin (3) is dispersed using a disperser modified from a Cavitron CD1010 (manufactured by Eurotech Co., Ltd.) to a high-temperature, high-pressure type. The Cavitron is operated with a composition ratio of 80% deionized water and 20% polyester resin, the pH is adjusted to 8.5 with ammonia, the rotor rotation speed is 60 Hz, the pressure is 5 kg / cm2, and the heat is heated to 140°C by a heat exchanger, to obtain a polyester resin dispersion (solid content 20%). The volume-average particle size of the resin particles in this dispersion is 180 nm. Ion-exchanged water is added to the dispersion to adjust the solid content to 20%, and this is designated as polyester resin particle dispersion (2).

[0203] [Preparation of Pigment Dispersion (1)] • Fluorescent yellow pigment (CI Pigment Yellow 101 (Radiant Color, Radglo VSF-0-01, emission peak wavelength 520nm)): 70 parts • Anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK): 30 parts (solid content concentration 20%) • Ion-exchanged water: 200 bottles The above materials are mixed and ground to a volume-average particle size of 300 nm using a continuous key mill (KMC-3, Inoue Seisakusho Co., Ltd.). The solid content is adjusted to 20% to obtain pigment dispersion (1).

[0204] [Preparation of Pigment Dispersion (2)] • Non-fluorescent green pigment (C.I. Pigment Green 36, manufactured by Toyocolor Co., Ltd., LIONOL GREEN 8624, reflection peak wavelength: 510 nm): 70 parts • Anionic surfactant (Neogen RK, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.): 30 parts (solid content concentration: 20%) • Ion-exchanged water: 200 parts The above materials are mixed and pulverized with a continuous key mill (KMC-3, Inoue Seisakusho Co., Ltd.) until a volume average particle diameter of 150 nm is obtained. The solid content is adjusted to 20% to obtain a pigment dispersion (2).

[0205] <Preparation of Release Agent Dispersion> [Preparation of Release Agent Dispersion (1)] • Polyethylene-based wax (hydrocarbon wax, trade name "Polywax 725" manufactured by Baker Petrolite Co., Ltd., melting temperature: 104°C): 270 parts • Anionic surfactant (Neogen RK, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., active ingredient content: 60%): 13.5 parts (as active ingredient, 3.0% relative to the release agent) • Ion-exchanged water: 21.6 parts The above components are mixed, the release agent is dissolved with a pressure discharge type homogenizer (Gaulin Homogenizer manufactured by Gaulin Inc.) at an internal liquid temperature of 120°C, then subjected to dispersion treatment at a dispersion pressure of 5 MPa for 120 minutes, followed by 40 MPa for 360 minutes, and cooled to obtain a release agent dispersion (1). The volume average particle diameter D50 of particles in this release agent dispersion (1) is 225 nm. Thereafter, ion-exchanged water is added to adjust the solid content concentration to 20.0%.

[0206] <Preparation of Toner Particles> [Preparation of Toner Particles (15)] • Polyester resin particle dispersion (1): 300 parts • Polyester resin particle dispersion (2): 50 parts • Pigment dispersion (1): 20 parts • Pigment dispersion (2): 20 parts • Release agent dispersion (1): 15 parts • Ion-exchanged water: 600 parts • Anionic surfactant (Dow Chemical Company, Dowfax 2A1): 2.9 parts The above materials are placed in a 3-liter reaction vessel equipped with a thermometer, pH meter, and stirrer. After adjusting the pH to 3.0 by adding 1.0% nitric acid at a temperature of 25°C, 100 parts of a 2% aqueous aluminum sulfate solution are added while dispersing the mixture at 3000 rpm using a homogenizer (IKA Ultra-Turrax T50). Once the addition is complete, increase the rotation speed to 5,000 rpm and stir for 5 minutes. Subsequently, a stirrer and mantle heater are installed in the reaction vessel, and the temperature is increased at a rate of 0.2°C / min until it reaches 40°C, and then at a rate of 0.05°C / min from 40°C to 53°C. The particle size is measured every 10 minutes using a Multisizer II (aperture diameter 50 μm, manufactured by Beckman Coulter). In this way, the first aggregated particles are formed, and when the volume-average particle size of the first aggregated particles reaches 5.0 μm, the temperature is maintained, and 460 parts of polyester resin particle dispersion (1) are added over a period of 5 minutes. After maintaining the temperature at 50°C for 30 minutes, 8 parts of a 20% solution of EDTA (ethylenediaminetetraacetic acid) were added relative to the total volume of the dispersion in the reaction vessel. Then, a 1 mol / liter aqueous sodium hydroxide solution was added to control the pH of the raw material dispersion to 9.0. Subsequently, the temperature was increased to 90°C at a rate of 1°C / min while adjusting the pH to 9.0 every 5°C, and the mixture was maintained at 90°C. Particle shape and surface properties were observed using an optical microscope and a field emission scanning electron microscope (FE-SEM). Particle coalescence was confirmed at 6 hours, so the container was cooled to 30°C in cooling water over 5 minutes. After cooling, the slurry is passed through a 15 μm nylon mesh to remove coarse powder, and the toner slurry that has passed through the mesh is filtered under reduced pressure using an aspirator. The solids remaining on the filter paper are crushed as finely as possible by hand and added to 10 times the amount of deionized water at 30°C, and stirred for 30 minutes. Next, the mixture is filtered under reduced pressure using an aspirator, the solids remaining on the filter paper are crushed as finely as possible by hand and added to 10 times the amount of deionized water at 30°C, stirred for 30 minutes, and then filtered under reduced pressure again using an aspirator, and the electrical conductivity of the filtrate is measured. This operation is repeated until the electrical conductivity of the filtrate is 10 μS / cm or less, and the solids are washed away. The washed solids are finely crushed in a wet / dry granulator (Cormill), and then vacuum-dried in a 35°C oven for 36 hours to obtain toner particles.

[0207] <Rating> (characteristic) The following characteristics of the toner for each example will be measured using the method described above. • Water absorption rate of toner particles • Surfactant content in toner particles • The oil coverage rate of the pigment exposed on the surface of the toner particles. • Percentage of the surface area of ​​pigment exposed on the toner particle surface

[0208] (Preparation of developer) Mix 8 parts of toner from each example with 92 parts of carrier (1) below using a V-blender to prepare the developer for each example.

[0209] -Creating Carrier (1)- • Ferrite particles (average particle size 35 μm): 100 parts • Toluene: 14 parts • Polymethyl methacrylate (MMA, weight-average molecular weight 75,000): 5 parts • Carbon black: 0.2 parts (VXC-72, manufactured by Cabot, volume resistivity: 100 Ωcm or less) The above materials, excluding ferrite particles, are dispersed in a sand mill to prepare a dispersion. This dispersion is then placed together with ferrite particles in a vacuum-degassed kneader, and carrier (1) is obtained by drying under reduced pressure while stirring.

[0210] (Evaluation device) Clean the main unit, developer unit, and toner cartridge of the Fujifilm Business Innovation Co., Ltd. DocuCentre Color 400 CP, thoroughly removing any previously installed developer and toner. Then, load the appropriate developer into the developer unit and the appropriate toner into the toner cartridge. This image forming apparatus will be used as an evaluation device, and the following evaluations will be performed.

[0211] (Evaluation of fluorescence intensity (spectral reflectance)) In an environment with a temperature of 28°C and a humidity of 80%RH, the amount of toner used to develop a 100% monochrome image on OS coated paper manufactured by Fujifilm Business Innovation Co., Ltd. was adjusted to 4.5 g / m2 using an evaluation device, and an image consisting only of toner, measuring 5 cm x 5 cm, was created. Using an X-Rite939 (manufactured by X-Rite, with a 4mm aperture), the spectral reflectance in the visible light region is measured at 10 random locations within the image plane. The spectral reflectance of the reflection peaks is then averaged and calculated. The results are then evaluated according to the following criteria. -Evaluation Criteria- A: Spectral reflectance at peak wavelength is 80% or higher B: Spectral reflectance at peak wavelength is 70% or more but less than 80% C: Spectral reflectance at peak wavelength is less than 70%

[0212] (Evaluation of image overlap in the initial image) After leaving the evaluation device in a high-temperature, high-humidity (28°C, 85%) environment for one day, 100,000 images with an image density of 40% are printed on A4 paper. Next, after leaving the evaluation device in a high-temperature, high-humidity (28°C, 85%) environment for three days, one image with an image density of 1% is printed on A4 paper. The density of the first printed image (background fogging) is measured using an X-Rite938 image densitometer (manufactured by X-Rite Corporation) and evaluated according to the evaluation criteria below. -Evaluation Criteria- G1: Fog concentration is less than 0.2. G2: Fog concentration is 0.2 or higher but less than 0.3. G3: Fog concentration is 0.3 or higher but less than 0.4. G4: Fog concentration is 0.4 or higher.

[0213] (Color vein evaluation) After leaving the evaluation device in a high-temperature, high-humidity (28°C, 85%) environment for one day, 100,000 images with an image density of 1% are printed on A4 paper. Then, the occurrence of color streaks is visually observed in 100 images, from the 99,900th to the 100,000th print, and evaluated according to the evaluation criteria below. -Evaluation Criteria- G1: No color streaks observed. G2: Number of sheets with color streaks ≤ 5 G3: Number of sheets with color streaks ≤ 10 sheets G4: Number of cards with color streaks > 10 cards

[0214] [Table 1]

[0215] From the above results, it can be seen that this embodiment suppresses the initial image fogging that occurs when toner is stored for a long period of time and then image is formed under high temperature and high humidity conditions, compared to the comparative example. Furthermore, this embodiment demonstrates that it is possible to form images with high fluorescence intensity and suppressed color streaks.

[0216] This embodiment includes the following aspects. (((1))) A toner for developing electrostatic images, comprising toner particles containing a binder resin and a pigment including a fluorescent organic pigment, wherein the pigment content is 4.0% by mass or more and 20.0% by mass or less relative to the toner particles, the water absorption rate of the toner particles is 1.0% or less, at least a portion of the pigment is exposed on the surface of the toner particles, and the oil coating rate of the pigment exposed on the surface of the toner particles is 20% or more. (((2))) The toner for developing electrostatic images according to (((1))), wherein the fluorescent organic pigment comprises an azomethine compound having an emission peak wavelength of 500 nm or more and 550 nm or less. (((3))) The toner for developing electrostatic images according to (((1))) or (((2))), wherein the pigment comprises a non-fluorescent organic pigment having a reflection peak wavelength of 480 nm or more and 540 nm or less. (((4))) A toner for developing electrostatic images according to any one of (((1))) to (((3))), wherein, when the surface of the toner particles is observed, the proportion of the area occupied by the pigment exposed on the surface of the toner particles is 10% or more and 50% or less of the total area of ​​the surface of the toner particles. (((5))) A toner for developing electrostatic images according to any one of (((1))) to (((4))), wherein the content of the fluorescent organic pigment relative to the toner particles is 3.0% by mass or more and 15.0% by mass or less. (((6))) The electrostatic image developing toner according to (((1))) to (((5))) comprises oil-treated silica particles treated with the oil as an external additive. (((7))) The toner for developing electrostatic images according to ((6)), wherein the content of the oil-treated silica particles is 0.5% by mass or more and 5.0% by mass or less relative to the toner particles. (((8))) The toner for developing electrostatic images according to ((6)), wherein the amount of oil released from the oil-treated silica particles relative to the oil-treated silica particles is 5.0% by mass or more and 30.0% by mass or less. (((9))) The toner for developing electrostatic images according to ((6)), wherein the volume average particle size of the oil-treated silica particles is 15.0 nm or more and 200 nm or less. (((10))) The toner for developing electrostatic images according to any one of (((1))) to (((9))), wherein the average circularity of the toner particles is less than 0.940. (((11))) A toner for developing electrostatic images according to any one of (((1))) to (((10))), comprising a kneading step of kneading the binder resin and a pigment containing the fluorescent organic pigment to obtain a kneaded product, and a pulverizing step of pulverizing the obtained kneaded product to obtain toner particles. (((12))) A electrostatic image developer containing the toner for developing electrostatic images described in any one of (((1))) to (((10))). (((14))) A toner cartridge that contains the electrostatic image developing toner described in any one of (((1))) to (((10))) and is attached to and detached from an image forming apparatus. (((14))) A process cartridge that is attached to and detached from an image forming apparatus, comprising a developing device that contains the electrostatic image developer described in (((12))) and develops an electrostatic image formed on the surface of an image holder as a toner image using the electrostatic image developer. (((15))) An image forming apparatus comprising: an image holder; a charging device for charging the surface of the image holder; an electrostatic image forming device for forming an electrostatic image on the charged surface of the image holder; a developing device for containing the electrostatic image developer described in (((12))) and developing the electrostatic image formed on the surface of the image holder as a toner image using the electrostatic image developer; a transfer device for transferring the toner image formed on the surface of the image holder to the surface of a recording medium; and a fixing device for fixing the toner image transferred to the surface of the recording medium.

[0217] The effects of the above embodiment are as follows: According to the invention of (((1))), an electrostatic image developing toner is provided which has toner particles containing a binder resin and a pigment containing a fluorescent organic pigment, wherein the pigment content is 4.0% by mass or more and 20.0% by mass or less relative to the toner particles, and compared to cases where the water absorption rate of the toner particles exceeds 1.0% or the oil coating rate of the pigment exposed on the surface of the toner particles is less than 20%, the initial image fogging that occurs when the toner is stored for a long period of time and an image is formed under high temperature and high humidity is suppressed. According to the invention of (((2))), an electrostatic image developing toner is provided which has toner particles containing a binder resin and a pigment containing a fluorescent organic pigment, wherein the pigment content is 4.0% by mass or more and 20.0% by mass or less relative to the toner particles, and which, compared to cases where the water absorption rate of the toner particles exceeds 1.0% or the oil coating rate of the pigment exposed on the surface of the toner particles is less than 20%, an electrostatic image developing toner is provided which can form a fluorescent yellow image with suppressed initial image fogging that occurs when the toner is stored for a long period of time and an image is formed under high temperature and high humidity. According to the invention of (((3))), an electrostatic image developing toner is provided which has toner particles containing a binder resin and a pigment containing a fluorescent organic pigment, wherein the pigment content is 4.0% by mass or more and 20.0% by mass or less relative to the toner particles, and which, compared to cases where the water absorption rate of the toner particles exceeds 1.0% or the oil coating rate of the pigment exposed on the surface of the toner particles is less than 20%, an electrostatic image developing toner is provided which can form a fluorescent green image with suppressed initial image fogging that occurs when the toner is stored for a long period of time and an image is formed under high temperature and high humidity. According to the invention of (((4))), when the surface of the toner particles is observed, the proportion of the area occupied by the pigment exposed on the surface of the toner particles is less than 10 area % or more than 50 area % of the total surface area of ​​the toner particles. In contrast, a toner for electrostatic image development is provided in which initial image fogging that occurs when the toner is stored for a long period of time and then an image is formed under high temperature and high humidity conditions is suppressed. According to the invention of (((5))), compared to cases where the content of fluorescent organic pigment in toner particles is less than 3.0% by mass or more than 15.0% by mass, an electrostatic image developing toner is provided in which initial image fogging that occurs when the toner is stored for a long period of time and then an image is formed under high temperature and high humidity is suppressed. According to the invention of (((6))), compared to the case in which silica particles that have not been treated with oil are included as an external additive, an electrostatic image developing toner is provided in which initial image fogging that occurs when an image is formed under high temperature and high humidity after the toner has been stored for a long period of time is suppressed. According to the invention of (((7))), compared to cases where the oil-treated silica particle content is less than 0.5% by mass or more than 5.0% by mass relative to the toner particles, an electrostatic image developing toner is provided in which initial image fogging that occurs when the toner is stored for a long period of time and then an image is formed under high temperature and high humidity is suppressed. According to the invention of ((8)), compared to the case where the amount of oil released from oil-treated silica particles relative to the oil-treated silica particles is less than 5.0% by mass, an electrostatic image developing toner is provided in which initial image fogging that occurs when the toner is stored for a long period of time and then an image is formed under high temperature and high humidity conditions is suppressed. According to the invention of (((9))), compared to the case where the volume average particle size of the oil-treated silica particles is less than 15.0 nm, an electrostatic image developing toner is provided in which initial image fogging that occurs when the toner is stored for a long period of time and then an image is formed under high temperature and high humidity conditions is suppressed. According to the invention of (((10))), an electrostatic image developing toner is provided having toner particles containing a binder resin and a pigment including a fluorescent organic pigment, wherein the pigment content is 4.0% by mass or more and 20.0% by mass or less relative to the toner particles. Compared to cases where the water absorption rate of the toner particles exceeds 1.0% or the oil coating rate of the pigment exposed on the surface of the toner particles is less than 20%, an electrostatic image developing toner is provided in which initial image fogging that occurs when the toner is stored for a long period of time and an image is formed under high temperature and high humidity is suppressed, even if the toner particles are irregularly shaped. According to the invention of (((11))), a method for producing electrostatic image developing toner is provided, which has toner particles containing a binder resin and a pigment containing a fluorescent organic pigment, wherein the pigment content is 4.0% by mass or more and 20.0% by mass or less relative to the toner particles, and compared to cases where the water absorption rate of the toner particles exceeds 1.0% or the oil coating rate of the pigment exposed on the surface of the toner particles is less than 20%, the method for producing electrostatic image developing toner is provided, which suppresses the initial image fogging that occurs when the toner is stored for a long period of time by kneading and grinding and then an image is formed under high temperature and high humidity. According to the inventions of (((12))), (((13))), (((14))), or (((15))), a toner cartridge, process cartridge, or image forming apparatus is provided that has toner particles containing a binder resin and a pigment including a fluorescent organic pigment, wherein the pigment content is less than 4.0% by mass or more than 20.0% by mass relative to the toner particles, the water absorption rate of the toner particles is more than 1.0%, at least a portion of the pigment is exposed on the surface of the toner particles, and the oil coating rate of the pigment exposed on the surface of the toner particles is less than 20%, compared to a toner for electrostatic image development that suppresses initial image fogging that occurs when an image is formed under high temperature and high humidity after the toner has been stored for a long period of time. [Explanation of Symbols]

[0218] 1P, 1Y, 1M, 1C, 1K, 1G Photoreceptor (an example of an image retainer) 2P, 2Y, 2M, 2C, 2K, 2G Charging Rolls (Example of a Charging Device) 3P, 3Y, 3M, 3C, 3K, 3G exposure equipment (an example of electrostatic image forming equipment) 4P, 4Y, 4M, 4C, 4K, 4G developing equipment (an example of a developing equipment) 5P, 5Y, 5M, 5C, 5K, 5G Primary Transfer Rolls (Example of a Primary Transfer Device) 6P, 6Y, 6M, 6C, 6K, 6G Photoconductor Cleaning Device (Example of a cleaning device) 8P, 8Y, 8M, 8C, 8K, 8G Toner Cartridges 10P, 10Y, 10M, 10C, 10K, 10G Image Forming Units 20. Intermediate transfer belt (an example of an intermediate transfer material) 21 Intermediate Transfer Body Cleaning Apparatus 22 Drive Roll 23 Support Roll 24 Opposing Roll 26. Secondary transfer roll (an example of a secondary transfer device) 28 Fixing device (an example of a fixing device) P Recording paper (an example of a recording medium)

[0219] 107 Photoreceptor (an example of an image-retaining element) 108 Charging Roll (Example of a Charging Device) 109 Exposure apparatus (an example of an electrostatic image forming apparatus) 111 Developing equipment (an example of a developing equipment) 112 Transfer device (an example of a transfer device) 113 Photoconductor Cleaning Device (Example of a cleaning device) 115 Fixing device (an example of a fixing device) 116 Mounting Rail 117 cabinets 118 Aperture for exposure 200 Process Cartridges 300 Recording paper (an example of a recording medium)

Claims

1. The toner particles contain a binder resin and a pigment containing a fluorescent organic pigment, The pigment content is 4.0% by mass or more and 20.0% by mass or less relative to the toner particles. The water absorption rate of the toner particles is 1.0% or less. At least a portion of the pigment is exposed on the surface of the toner particles, A toner for developing electrostatic images, wherein the oil coating rate of the pigment exposed on the surface of the toner particles is 20% or more.

2. The toner for developing electrostatic images according to claim 1, wherein the fluorescent organic pigment comprises an azomethine compound having an emission peak wavelength of 500 nm or more and 550 nm or less.

3. The toner for developing electrostatic images according to claim 2, wherein the pigment comprises a non-fluorescent organic pigment having a reflection peak wavelength of 480 nm or more and 540 nm or less.

4. The electrostatic image developing toner according to claim 1, wherein, when the surface of the toner particles is observed, the proportion of the area occupied by the pigment exposed on the surface of the toner particles is 10% or more and 50% or less of the total surface area of ​​the toner particles.

5. The toner for developing electrostatic images according to claim 1, wherein the content of the fluorescent organic pigment relative to the toner particles is 3.0% by mass or more and 15.0% by mass or less.

6. The toner for developing electrostatic images according to claim 1, comprising oil-treated silica particles treated with the oil as an external additive.

7. The toner for developing electrostatic images according to claim 6, wherein the content of the oil-treated silica particles is 0.5% by mass or more and 5.0% by mass or less relative to the toner particles.

8. The toner for developing electrostatic images according to claim 6, wherein the amount of oil released from the oil-treated silica particles relative to the oil-treated silica particles is 5.0% by mass or more and 30.0% by mass or less.

9. The toner for developing electrostatic images according to claim 6, wherein the volume-average particle size of the oil-treated silica particles is 15.0 nm or more and 200 nm or less.

10. The toner for developing electrostatic images according to claim 1, wherein the average circularity of the toner particles is less than 0.

940.

11. A kneading step to obtain a compound by kneading the binder resin and the pigment containing the fluorescent organic pigment, A grinding step is performed to grind the obtained compound to obtain toner particles, A method for manufacturing electrostatic image developing toner according to any one of claims 1 to 10.

12. A electrostatic image developer comprising the electrostatic image developing toner according to any one of claims 1 to 10.

13. A toner cartridge containing the electrostatic image developing toner described in any one of claims 1 to 10, which is attached to and detached from an image forming apparatus.

14. A process cartridge that is attached to and detached from an image forming apparatus, comprising a developing apparatus that contains the electrostatic image developer described in claim 12 and develops an electrostatic image formed on the surface of an image holder as a toner image using the electrostatic image developer.

15. Image holder and, A charging device for charging the surface of the image holder, A static charge image forming apparatus for forming a static charge image on the surface of the charged image holder, A developing apparatus comprising: containing the electrostatic image developer described in claim 12; and developing an electrostatic image formed on the surface of the image holder as a toner image using the electrostatic image developer; A transfer device for transferring a toner image formed on the surface of the image holder to the surface of a recording medium, A fixing device for fixing the toner image transferred to the surface of the recording medium, An image forming apparatus equipped with the following features.

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