Toner for developing electrostatic images

Abstract

To provide a toner for electrostatic image development that can achieve both low-temperature fixing properties and suppression of gloss unevenness in the resulting image. [Solution] The electrostatic image developing toner comprises toner matrix particles having a binder resin and a wax, and an external additive attached to the surface of the toner matrix particles. The binder resin comprises a crystalline polyester resin and an amorphous resin. The external additive comprises inorganic particles surface-treated with a surface treatment agent. The hydrophobicity of the inorganic particles is 80% or more. The HSP value of the wax (HSP1) and the HSP value of the surface treatment agent (HSP2) satisfy the following formula (A). HSP1-HSP2≧2.7 Formula (A)

Description

[Technical Field]

[0001] This invention relates to a toner for developing electrostatic images. [Background technology]

[0002] In electrophotographic image formation, there has been a growing demand for low-temperature fixing in recent years, in order to further conserve energy with the aim of increasing print speed and reducing environmental impact. Toners used for this purpose require lowering the melting temperature and melt viscosity of the binder resin, and technologies have been proposed to improve low-temperature fixing by adding crystalline resins such as crystalline polyester resins.

[0003] For example, Patent Document 1 describes an image-forming toner containing at least a thermoplastic resin (A), a colorant (B), a wax (C), and a crystalline polymer (D). Such an image-forming toner is said to have improved low-temperature fixability. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2004-206081 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, according to the inventors' findings, the image forming toner described in Patent Document 1 was unsatisfactory in terms of suppressing gloss unevenness in the resulting image.

[0006] The present invention has been made in view of the above-mentioned problems, and aims to provide a toner for electrostatic image development that can achieve both low-temperature fixing properties and suppression of gloss unevenness in the obtained image. [Means for solving the problem]

[0007] One aspect of the present invention for solving the above problems relates to an electrostatic charge image developing toner described in the following [1] to [7].

[0008] [1] Toner base particles having a binder resin and a wax, including an external additive adhered to the surface of the toner base particles, the binder resin includes a crystalline polyester resin and an amorphous resin, the external additive includes inorganic particles surface-treated with a surface treatment agent, the hydrophobicization rate of the inorganic particles is 80% or more, the HSP value (HSP1) of the wax and the HSP value (HSP2) of the surface treatment agent satisfy the following formula (A), An electrostatic charge image developing toner. HSP1 - HSP2 ≥ 2.7 Formula (A)

[0009] [2] The surface treatment agent is silicone oil, the content of free silicone oil relative to the content mass of the surface-treated inorganic particles is 1 ppm to 15000 ppm, The electrostatic charge image developing toner according to [1].

[0010] [3] The content of free silicone oil relative to the content mass of the surface-treated inorganic particles is 1 ppm to 5000 ppm, The electrostatic charge image developing toner according to [2].

[0011] <000​​​​​​​​​​​[6] The content of the crystalline polyester resin relative to the total mass of the toner matrix particles is 5% by mass to 20% by mass. Toner for developing electrostatic images as described in any of [1] to [5].

[0014] [7] The content of the external additive relative to the total mass of the toner matrix particles is 0.3% by mass to 3.0% by mass. Toner for developing electrostatic images as described in any of [1] to [6]. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a toner for electrostatic image development that can achieve both low-temperature fixing properties and suppression of gloss unevenness in the obtained image. [Modes for carrying out the invention]

[0016] The embodiments of the present invention will be described in detail below. However, the present invention is not limited to the following embodiments.

[0017] In this specification, numerical ranges represented by "~" mean a range that includes the numbers written before and after "~" as the lower and upper limits, respectively.

[0018] Furthermore, in this specification, "(meth)acrylate" means either acrylate or methacrylate, or both, and "(meth)acrylic" means either acrylic or methacrylic, or both.

[0019] 1. Toner for developing electrostatic images The electrostatic image developing toner (hereinafter also simply referred to as "toner") according to this embodiment is Toner matrix particles having a binder resin, a colorant, and a wax, The toner matrix particles include an external additive attached to the surface of the toner matrix particles, The binder resin comprises a crystalline polyester resin and the amorphous resin. The aforementioned external additive contains inorganic particles that have been surface-treated with a surface treatment agent. The hydrophobicity rate of the inorganic particles is 80% or more. The HSP value of the wax (HSP1) and the HSP value of the surface treatment agent (HSP2) satisfy the following formula (A). HSP1-HSP2≧2.7 Formula (A)

[0020] When the toner matrix particles contain crystalline polyester, the crystalline polyester and amorphous resin become miscible, resulting in a melting point depression. This can easily lead to a decrease in the glass transition temperature, melting temperature, and melt viscosity of the binder resin.

[0021] On the other hand, when printing onto a recording medium using toner, the toner applied to the recording medium undergoes a fixing process. In the fixing process, the toner applied to the recording medium is heated, causing the binder resin to melt and the unfixed image to be fixed to the recording medium. At this time, the wax contained in the toner matrix particles seeps out onto the toner surface, providing release properties between the fixing roller and the image on the recording medium. If there is an uneven dispersion state of crystalline polyester in the toner matrix particles, or temperature unevenness in the fuser, and some of the binder resin on the image surface does not completely melt, the surface of the binder resin after fixing is prone to becoming uneven. However, if the wax seeps out sufficiently and covers the outermost layer of the image, the smoothness will be relatively high. However, the amount of wax seeping out is not uniform across the entire surface of the binder resin, and unevenness in the amount of seeping may occur from place to place. In that case, areas with a large amount of wax seeping out will have higher smoothness and lower light scattering, while areas with a small amount of wax seeping out will not easily become smooth and will not easily decrease light scattering. As a result, it is thought that unevenness in the gloss of the image is likely to occur.

[0022] The above-mentioned electrostatic image developing toner makes it possible to achieve both improved low-temperature fixing properties and suppression of gloss unevenness in the resulting image. The reason for this is not entirely clear, but it is thought to be as follows.

[0023] The toner according to this embodiment contains an external additive to impart chargeability and fluidity to the surface of the toner matrix particles, and the external additive contains inorganic particles whose surface has been treated with a surface treatment agent. When wax seeps out from the toner surface during the fixing process, if the HSP value of the surface treatment agent is smaller than that of the wax (higher hydrophobicity), the inorganic particles contained in the external additive will try to move towards the more hydrophobic air interface. As a result, the inorganic particles are more easily transported to the outermost surface of the image. Consequently, the inorganic particles tend to be unevenly distributed on the outermost surface of the wax. As a result of the uneven distribution of inorganic particles on the outermost surface of the wax, the wax tends to aggregate with other wax particles and the inorganic particles tend to aggregate with other inorganic particles, creating areas within the plane where inorganic particles are unevenly distributed and areas where inorganic particles are not unevenly distributed (areas with a higher proportion of wax). As a result, an in-plane difference occurs in the surface tension of the wax, and the surface of the wax tends to become moderately uneven. As described above, the amount of wax seeping onto the toner surface increases, and even if the outermost surface of the toner is covered with wax, it becomes difficult to achieve high smoothness compared to when it is not covered. As a result, even if the amount of wax seeping out changes within the image plane, uneven gloss in the image is less likely to occur.

[0024] In particular, when the HSP value of the wax (HSP1) and the HSP value of the surface treatment agent (HSP2) satisfy the following equation (A), the hydrophobicity of the surface treatment agent becomes sufficiently higher than that of the wax, and the compatibility between the wax and the surface treatment agent also decreases. As a result, inorganic particles tend to be more unevenly distributed on the outermost surface of the toner, and the aforementioned effect of suppressing uneven gloss becomes more pronounced. HSP1-HSP2≧2.7 Formula (A)

[0025] Furthermore, if the hydrophobicity rate of the inorganic particles is 80% or higher, the surface of the inorganic particles can be sufficiently coated with the surface treatment agent, making it easier for the inorganic particles to be concentrated on the outermost surface of the toner, thus further enhancing the effect of suppressing the gloss unevenness mentioned above.

[0026] Based on the above, it is believed that both low-temperature fixation and suppression of gloss unevenness in the resulting image can be achieved.

[0027] The HSP values ​​of the wax (HSP1) and the surface treatment agent (HSP2) in this application are calculated as follows. The HSP values ​​are calculated using the Hansen method. By using HSPiP (Ver. 6.0.04) and inputting the chemical structure of the compound to be calculated using the linear molecular notation Smiles formula, the Hansen solubility parameters (δD, δP, δH) of each compound can be calculated. From these values ​​(δD 2 +δP 2 +δH 2 ) 0.5 By performing this calculation, the HSP values ​​(HSP1 and HSP2) for each compound are determined.

[0028] 1-1. External Additives The external additive contains inorganic particles that have been surface-treated with a surface treatment agent.

[0029] 1-1-1.Inorganic particles Examples of inorganic particles include metal oxide particles such as silica, alumina, and titanium oxide, as well as titanate particles such as strontium titanate and zinc titanate. Among these, silica is preferred from the viewpoint of fluidity, electrostatic chargeability, etc.

[0030] In particular, when silica is used as inorganic particles, silica produced by known methods or commercially available silica can be used, and among these, monodisperse spherical silica is preferred. This is because, being monodisperse and spherical, it disperses uniformly on the surface of the toner matrix particles, making it easier to suppress gloss unevenness. Monodisperse spherical silica can be produced by wet methods such as the sol-gel method. The dispersibility and shape (spherical, non-spherical, etc.) of silica can be freely controlled by manufacturing conditions such as the weight ratio of alkoxysilane, ammonia, alcohol, and water in the hydrolysis and condensation polymerization steps of the sol-gel method, reaction temperature, stirring speed, and supply speed.

[0031] Furthermore, inorganic particles can be manufactured by known methods, including the fumed process. For example, silica manufactured by the fumed process (hereinafter also referred to as "fumed silica") can be produced by introducing a silicon compound (such as silicon tetrachloride) or silicon into an oxygen-hydrogen flame and allowing it to undergo a hydrolysis reaction. Commercially available inorganic particles manufactured by the fumed process may also be used.

[0032] 1-1-2. Surface treatment agents Surface treatment agents used for surface treatment of inorganic particles may include known hydrophobic surface treatment agents. Examples of surface treatment agents include silicone oil, hexamethyldisilazane, dichlorodimethylsilane, and alkyltrialkoxysilane. Among these, the surface treatment agent preferably contains silicone oil, and more preferably silicone oil.

[0033] The silicone oil used as a surface treatment agent may be a reactive silicone oil, a non-reactive silicone oil, or a mixture thereof. The inorganic particles surface-treated with the surface treatment agent according to this embodiment may have a multilayer structure including a coating layer formed from the surface treatment agent on the surface of the inorganic particles, or a single-layer structure. The coating layer may also have a single-layer or multilayer structure. For example, the coating layer may be formed solely from reactive silicone oil, solely from non-reactive silicone oil, or contain components other than silicone oil. Furthermore, the coating layer may be formed from reactive silicone oil and non-reactive silicone oil, or it may be a multilayer coating layer including a coating layer formed from reactive silicone oil and a coating layer formed from non-reactive silicone oil. In the case of a multilayer coating layer, for example, it may be a two-layer coating layer consisting of a coating layer formed from reactive silicone oil and a coating layer formed from non-reactive silicone oil, with either layer being the outermost surface.

[0034] The main chain (main skeleton) consisting of siloxane bonds contained in the silicone oil is not particularly limited, but it is preferable that it has dimethylsiloxane structural units, and more preferably that it consists of dimethylsiloxane structural units.

[0035] Silicone oil may also be a modified silicone oil. Examples of modified silicone oils include amino-modified silicone oil, epoxy-modified silicone oil, carboxyl-modified silicone oil, carbinol-modified silicone oil, methacrylic-modified silicone oil, mercapto-modified silicone oil, phenol-modified silicone oil, silanol-dimethyl oil at both ends, reactive-modified silicone oil at one end, heterofunctional-group-modified silicone oil, polyether-modified silicone oil, higher fatty acid ester-modified silicone oil, hydrophilic special-modified silicone oil, higher alkoxy-modified silicone oil, higher fatty acid-containing modified silicone oil, fluorine-modified silicone oil, and other modified silicone oils.

[0036] 1-1-2-1. Reactive Silicone Oil Reactive silicone oil has reactive functional groups at the terminals and / or side chains of the main chain, which consists of siloxane bonds. From the viewpoint of increasing reactivity to the inorganic particle surface and increasing the hydrophobicity, it is preferable that the silicone oil contains reactive silicone oil, and more preferably that it is reactive silicone oil. The ratio of reactive silicone oil to the total mass of the surface treatment agent used to form the coating layer can be 90% to 100% by mass.

[0037] Examples of reactive functional groups found in reactive silicones include Si-H moieties (hydrogen atoms directly attached to silicon), hydroxyl groups, amino groups, carbinol groups, epoxy groups, and carboxyl groups.

[0038] Among these, it is preferable that the reactive functional group contains a hydroxyl group, from the viewpoint of facilitating bonding by reacting with the hydroxyl groups on the surface of the inorganic particles when the inorganic particles contain inorganic oxide particles or when the surface of the inorganic particles is partially oxidized. For example, when the inorganic particles are silica, a Si-O-Si bond can be formed by the reaction between the Si-OH on the silica surface and the hydroxyl group contained in the reactive functional group.

[0039] Furthermore, the reactive silicone oil preferably contains terminal silanol dimethyl polysilicone and / or methyl hydrogen polysilicone, and more preferably consists of terminal silanol dimethyl polysilicone and / or methyl hydrogen polysilicone.

[0040] Terminal silanol dimethyl polysilicone is, for example, a compound represented by the following formula (1).

[0041] [ka]

[0042] In the above equation (1), R 1 R represents an organic group other than a methyl group. m represents an integer of 1 or more, and n represents an integer of 0 or 1 or more. 1 The hydrocarbon group is preferably a hydrocarbon group having 2 or more carbon atoms, and more preferably a hydrocarbon group having 2 to 6 carbon atoms. The repeating units are -(Si(CH3)2-O)- and -(SiR 1 (CH3)-O)- is not limited to block copolymers; terminal silanol dimethyl polysilicone may be an alternating copolymer, a random copolymer, or a block copolymer.

[0043] In the above formula (1), a reactive silicone oil having hydroxyl groups at both ends of the polydimethylsiloxane, where n is 0, can also be suitably used. Alternatively, the polydimethylsiloxane may have a hydroxyl group at one end, or it may have at least one hydroxyl group at the end of the polydimethylsiloxane.

[0044] Furthermore, methylhydrogen polysilicone can be any compound that has hydrogen atoms in the side chains of its siloxane chain, for example, the compound shown in formula (2) below.

[0045] [ka]

[0046] In formula (2) above, m represents 0 or an integer greater than or equal to 1, and n represents an integer greater than or equal to 1. Also, m + n ≥ 1. The repeating units -(Si(CH3)2-O)- and -(SiH(CH3)-O)- are not limited to block copolymers, and the methyl hydrogen polysilicone may be an alternating copolymer, a random copolymer, or a block copolymer.

[0047] These reactive silicone oils may be manufactured by known methods or may be commercially available. One or more reactive silicone oils may be used.

[0048] The kinematic viscosity (measured at 25°C) of the reactive silicone oil (hereinafter referred to as "viscosity") is not particularly limited, but is preferably between 30 cSt and 100 cSt. When the viscosity is 30 cSt or higher, the molecular weight increases, which suppresses the volatilization of the reactive silicone oil during heat treatment, allowing the surface treatment to proceed more smoothly and reducing the environmental burden. On the other hand, when the viscosity is 100 cSt or lower, the aggregation of inorganic particles is more easily suppressed, and fluidity tends to increase. Kinematic viscosity is a value measured using, for example, ARES-G2 (manufactured by TA Instruments).

[0049] Furthermore, the weight-average molecular weight range of the reactive silicone oil is preferably 1,000 to 20,000, and more preferably 3,000 to 10,000. When it is 1,000 or higher, the heat resistance of the toner tends to improve, and when it is 20,000 or lower, the viscosity of the surface treatment agent is appropriately adjusted, so the inorganic particles treated with the surface treatment agent tend to be unevenly distributed on the wax surface, and the effect of suppressing gloss unevenness tends to improve. The weight-average molecular weight is a value measured by gel permeation chromatography (GPC).

[0050] Specifically, the instrument "HLC-8120GPC" (manufactured by Tosoh Corporation) and the column "TSKguardcolumn+TSKgelSuperHZ-M3" (manufactured by Tosoh Corporation) are used. The measurement conditions are a column temperature of 40°C, tetrahydrofuran (THF) as the carrier solvent, and a carrier solvent flow rate of 0.2 ml / min. The sample to be measured (amorphous resin) is dissolved in tetrahydrofuran to a concentration of 1 mg / ml by dissolving it in an ultrasonic disperser for 5 minutes at room temperature. The tetrahydrofuran solution of the sample to be measured is processed through a membrane filter with a pore size of 0.2 μm. 10 μL of this sample solution is injected into the instrument together with the carrier solvent and detected using a refractive index detector (RI detector). The weight-average molecular weight and number-average molecular weight of the sample to be measured can be calculated as polystyrene equivalent values ​​using a calibration curve prepared using 10 monodisperse polystyrene standard particles.

[0051] The content of reactive silicone oil is not particularly limited, but is preferably 1% to 15% by mass, more preferably 2% to 12% by mass, and even more preferably 3% to 10% by mass, relative to the total mass of inorganic particles. When the reactive silicone oil content is 1% by mass or more, the hydrophobicity rate tends to increase, and the hydrophobicity rate of inorganic particles tends to increase. When the reactive silicone oil content is 15% by mass or less, aggregation of inorganic particles tends to be suppressed, and fluidity tends to be maintained.

[0052] 1-1-2-2. Non-reactive silicone oil The non-reactive silicone oil can be any silicone oil that does not have the reactive functional groups mentioned above. For example, it may be polydimethylsiloxane, or a polysiloxane having alkyl groups other than methyl groups, aralkyl groups, polyether groups, fluoroalkyl groups, ester groups, phenyl groups, etc., in its side chains. These non-reactive silicone oils may be manufactured by known methods or may be commercially available. One or more non-reactive silicone oils may be used.

[0053] The kinematic viscosity (measured at a temperature of 25°C) of the non-reactive silicone oil (hereinafter referred to as "viscosity") is not particularly limited, but is preferably between 30 cSt and 100 cSt. When the viscosity is 30 cSt or higher, the molecular weight increases, which suppresses the volatilization of the non-reactive silicone oil during heat treatment and reduces the environmental burden. On the other hand, when the viscosity is 100 cSt or lower, the aggregation of inorganic particles is more easily suppressed, and fluidity tends to increase. Kinematic viscosity is a value measured in the same manner as described above.

[0054] Furthermore, the weight-average molecular weight range of the non-reactive silicone oil is preferably 1,000 to 20,000, and more preferably 3,000 to 10,000. When it is 1,000 or higher, the heat resistance of the toner tends to improve, and when it is 20,000 or lower, the viscosity of the surface treatment agent is appropriately adjusted, so the inorganic particles treated with the surface treatment agent tend to be unevenly distributed on the wax surface, and the effect of suppressing uneven gloss tends to improve. The weight-average molecular weight is a value measured in the same way as described above.

[0055] The content of non-reactive silicone oil is not particularly limited, but is preferably 1% to 15% by mass, more preferably 2% to 12% by mass, and even more preferably 3% to 10% by mass, relative to the total mass of inorganic particles. When the content of non-reactive silicone oil is 1% by mass or more, the hydrophobicity rate tends to increase, and the hydrophobicity rate of inorganic particles tends to increase. When the content of non-reactive silicone oil is 15% by mass or less, aggregation of inorganic particles tends to be suppressed, and fluidity tends to be maintained.

[0056] The mass ratio of reactive silicone oil to non-reactive silicone oil in the surface treatment agent is not particularly limited, but it is preferably between 0.2:1.0 and 4.0:1.0. Setting it to this ratio makes it easier to increase fluidity and adjust the electrostatic properties.

[0057] 1-1-2-3. Characteristics of surface treatment agents When using a component other than silicone oil as a surface treatment agent, the weight-average molecular weight of the surface treatment agent is preferably between 1,000 and 20,000. A value of 1,000 or higher tends to improve the heat resistance of the toner during storage, while a value of 20,000 or lower allows for appropriate adjustment of the viscosity of the surface treatment agent, making it easier for the inorganic particles treated by the surface treatment agent to be unevenly distributed on the wax surface, thus improving the suppression of uneven gloss. The weight-average molecular weight is a value measured in the same manner as described above.

[0058] 1-1-3. Characteristics of external additives The particle size of the inorganic particles contained in the external additive is not particularly limited, but the primary particle size is preferably 5 nm to 150 nm, more preferably 10 nm to 150 nm, even more preferably 10 nm to 120 nm, and still more preferably 20 nm to 80 nm. When the primary particle size is 5 nm or larger, surface irregularities are more easily formed when the particles are concentrated near the toner surface, which enhances the effect of suppressing gloss unevenness. When the particle size is 20 nm or larger, surface irregularities are more easily formed in the areas where the inorganic particles are concentrated, which enhances the effect of suppressing gloss unevenness. Heat resistance during storage is also enhanced. When the primary particle size is 150 nm or smaller, the mobility of the inorganic particles is more likely to increase, leading to increased concentration on the toner surface and enhancing the effect of suppressing gloss unevenness. When the particle size is 80 nm or smaller, fluidity is more likely to increase. The particle size is a value obtained, for example, by taking the arithmetic mean of the particle sizes of 1000 arbitrarily selected particles observed by a transmission electron microscope (TEM).

[0059] The inorganic particles contained in the external additive have a specific surface area (hereinafter also referred to as "BET specific surface area") by the nitrogen adsorption method (BET) of 10 m 2 / g to 10 4 m 2 / g, preferably 20 m 2 / g to 10 2 m 2 / g. When the BET specific surface area is 10 m 2 2 / g or more, the fluidity of the toner is likely to increase. When the BET specific surface area is 10 4 m 2 / g or less, it becomes difficult to be buried in the toner base particles, and the temporal stability of the toner performance is likely to increase. The BET specific surface area is, for example, a value measured by an automatic specific surface area measuring device GEMINI 2360 (manufactured by Shimadzu-Micromeritics).

[0060] The hydrophobicization rate of the inorganic particles contained in the external additive is 80% or more, preferably 80% to 100%, and more preferably 90% to 100%. When the hydrophobicization rate is 80% or more, the charging property particularly under high temperature and high humidity is likely to increase, and the inorganic particles are likely to be unevenly distributed on the surface, so the effect of suppressing gloss unevenness is likely to increase.

[0061] The hydrophobicization rate of the inorganic particles is a value measured as follows. For example, for a dispersion obtained by adding pure water to inorganic particles surface-treated with a surface treatment agent and performing a dispersion treatment, the transmittance at a wavelength of 500 nm measured with a colorimeter or the like can be used as the hydrophobicization rate. This is because inorganic particles sufficiently surface-treated with a surface treatment agent precipitate or float on the water surface without dispersing in water, so it is difficult for the turbidity of the dispersion to increase and it is easy for the transmittance of visible light of the dispersion to increase. When two or more kinds of inorganic particles surface-treated with an external additive are contained, the hydrophobicization rate of the inorganic particles in the present application refers to the hydrophobicization rate of the inorganic particles having the largest content based on mass. Also, when there are two or more kinds of inorganic particles having the largest content based on mass, it refers to the average value of the respective hydrophobicization rates corresponding to the plurality of inorganic particles having the largest content based on mass.

[0062] Specifically, 1.0 g of inorganic particles is weighed into a 200 mL separatory funnel, and 100 mL of pure water is added to it. The mixture is then shaken in a turbler mixer for 10 minutes. After shaking, it is allowed to stand for 10 minutes, and 20-30 mL of the lower layer of liquid is withdrawn from the funnel. The lower layer of liquid is then separated into a quartz cell with a path length of 10 mm. Using pure water as a blank, the transmittance of light at a wavelength of 500 mm is measured with a colorimeter and can be considered as the hydrophobicity.

[0063] When the surface treatment agent is silicone oil, the content of free silicone oil relative to the mass of surface-treated inorganic particles is preferably 1 ppm to 15,000 ppm, more preferably 1 ppm to 10,000 ppm, and even more preferably 1 ppm to 5,000 ppm. Most preferably 1 ppm to 1,000 ppm. When the free silicone oil content is 1 ppm or more, in the process of cleaning the toner remaining on the photoreceptor drum that performs image formation, the free oil acts as a lubricant, stabilizing the behavior of the cleaning blade and improving cleaning performance. It also tends to enhance the effect of suppressing uneven gloss. When the free silicone oil content is 15,000 ppm or less, when wax seeps out during the fixing process, some of the silicone oil contained in the external additive does not easily diffuse into the wax, making it difficult to increase the compatibility between the wax and inorganic particles. As a result, inorganic particles tend to be unevenly distributed on the surface, and it tends to enhance the effect of suppressing uneven gloss. It also tends to improve the heat resistance and fluidity of the toner. Furthermore, if the external additive contains two or more types of surface-treated inorganic particles, the free silicone oil content in this application refers to the mass ratio of the free silicone oil content in the inorganic particle with the highest mass content to the mass of the inorganic particle with the highest mass content. Also, if there are two or more types of inorganic particles with the highest mass content, it refers to the average value of the free silicone oil content corresponding to each of the multiple inorganic particles with the highest mass content.

[0064] The content of free silicone oil relative to the mass of surface-treated inorganic particles (hereinafter also referred to as "surface-treated inorganic particles") is measured as follows: Surface-treated inorganic particles are immersed in an organic solvent (e.g., hexane, etc.) and silicone oil that has not reacted with the inorganic particles (free silicone oil) is extracted. The carbon content of the surface-treated inorganic particles before and after the extraction operation is analyzed using a known carbon analyzer (e.g., "EMIA-110" manufactured by Horiba, Ltd.). The difference between the carbon content of the surface-treated inorganic particles before the extraction operation and the carbon content of the surface-treated inorganic particles after the extraction operation can be considered as the content of free silicone oil relative to the total amount of surface-treated inorganic particles.

[0065] Specifically, for example, using a Soxhlet extraction apparatus manufactured by BUCHI, 0.5 g of the external additive is placed in a cylindrical filter paper with a diameter of 28 mm, hexane is used as the extraction solvent, and the free silicone oil in the external additive is extracted under conditions of extraction time of 60 minutes and rinsing time of 30 minutes. The carbon content of the external additive before and after extraction is measured using "EMIA-110" manufactured by Horiba, Ltd. By subtracting the carbon content of the external additive after the extraction and removal of free silicone oil from the carbon content of the external additive before extraction, the content of free silicone oil relative to the total amount of external additive can be calculated.

[0066] External additives may or may not contain so-called fluidizers, cleaning aids, etc., in order to improve fluidity, electrostatic properties, cleaning properties, etc., in the toner matrix particles. The external additives may also consist of inorganic particles whose surfaces have been treated with a surface treatment agent.

[0067] The content of inorganic particles surface-treated with a surface treatment agent contained in the external additive is preferably 0.1% to 4.5% by mass, more preferably 0.3% to 3.0% by mass, and more preferably 1.0% to 2.0% by mass, relative to the total mass of the toner matrix particles. If it is 0.1% by mass or more, the coating rate of the toner matrix particles with the external additive tends to increase, which tends to increase fluidity and tends to increase the effect of suppressing gloss unevenness. If it is 0.3% by mass or more, fluidity tends to increase even more. If it is 4.5% by mass or less, the coating rate does not become too high, which promotes fusion between toner matrix particles during fixing and tends to increase low-temperature fixing performance.

[0068] 1-1-4. Method for producing inorganic particles surface-treated with a surface treatment agent Inorganic particles that have been surface-treated with a surface treatment agent can be manufactured by known methods.

[0069] In particular, if the surface treatment agent is a silicone oil, it may be manufactured by a method that includes, for example, the following steps. (i) A step of preparing a mixture containing inorganic particles and silicone oil (preparation step) (ii) A step of heat-treating the mixture at a temperature of 80 to 380°C (heat treatment step)

[0070] 1-1-4-1.(i) Preparation process The preparation process is not particularly limited as long as it can coat the surface of the inorganic particles with silicone oil. For example, a method of mixing inorganic particles with vaporized silicone oil under stirring, or a method of spraying silicone oil onto inorganic particles under stirring, can be suitably used.

[0071] In this case, the silicone oil may be used after being diluted or dispersed with hexane, toluene, alcohol (aliphatic alcohols with 1 to 8 carbon atoms such as methanol, ethanol, and propanol), acetone, water, or mixtures thereof. The concentration of the silicone oil in the diluted or dispersed solution can be 5% to 70% by mass relative to the total mass of the solution.

[0072] The temperature conditions in the preparation process are not particularly limited, but can be, for example, 10°C to 40°C. Furthermore, the preparation process is preferably carried out under an inert gas atmosphere, and examples of inert gases include nitrogen gas, helium gas, and argon gas.

[0073] 1-1-4-2. (ii) Heat treatment process The temperature conditions in the heat treatment process are not particularly limited, but are preferably 80°C to 380°C, more preferably 150°C to 380°C, and even more preferably 280°C to 380°C. When the temperature is 80°C or higher, the reaction of the silicone oil with inorganic particles proceeds more easily, the hydrophobicity rate tends to increase, and the amount of free silicone oil, as described later, tends to decrease. When the temperature is 380°C or lower, the decomposition of the silicone oil tends to be suppressed, and the coating effect of the silicone oil tends to be obtained more easily.

[0074] The heat treatment process is preferably carried out under an inert gas atmosphere. Examples of inert gases include nitrogen gas, helium gas, and argon gas. In particular, the preparation process may be carried out in a sealed reactor, and the heat treatment process may be carried out while maintaining that atmosphere.

[0075] The processing time in the heat treatment process should be sufficient for the silicone oil to be fixed to the surface of the inorganic particles, and can be between 5 and 180 minutes.

[0076] 1-2. Toner matrix particles The toner matrix particles according to this embodiment include a binder resin, a crystalline polyester, and a wax. Furthermore, it is preferable that the toner matrix particles according to this embodiment also contain a colorant.

[0077] 1-2-1. Wax The wax according to this embodiment is not particularly limited as long as the HSP value of the wax (HSP1) and the HSP value of the surface treatment agent (HSP2) satisfy the following formula (A). Note that each HSP value is calculated using the same method as described above. HSP1-HSP2≧2.7 Formula (A)

[0078] If two or more types of wax are included, HSP1 refers to the HSP value of the wax with the highest mass content among the two or more types of wax. Similarly, if two or more types of surface treatment agents are included, HSP2 refers to the HSP value of the surface treatment agent with the highest mass content among the two or more types of surface treatment agents. Furthermore, if there are two or more waxes with the highest mass content, it refers to the average value of the HSP1 corresponding to the multiple waxes with the highest mass content, and it refers to the average value of the HSP2 corresponding to the multiple surface treatment agents with the highest mass content.

[0079] The HSP1-HSP2 value is 2.7 or higher, preferably 3.5 or higher, and more preferably 4.0 or higher. Furthermore, the HSP1-HSP2 value is preferably 5.0 or lower. When it is 3.5 or higher, inorganic particles tend to be more concentrated towards the air interface, which helps to suppress uneven gloss. When it is 5.0 or lower, the polarity of the wax does not become too high, and the compatibility with the binder resin etc. is moderately reduced, so the glass transition temperature of the binder resin does not decrease easily, and the heat-resistant storage properties tend to improve.

[0080] Examples of waxes that satisfy formula (A) include waxes in which functional groups containing oxygen or nitrogen atoms are appropriately introduced to moderately increase polarity. Examples of functional groups containing oxygen or nitrogen atoms include ester groups, amide groups, carboxyl groups, hydroxyl groups, and ether groups.

[0081] Furthermore, in the fixing process, from the viewpoint of facilitating the toner from seeping out of the toner matrix particles, it is preferable that the wax be a compound having long-chain hydrocarbon groups so that it has low compatibility with fixing resins and crystalline polyesters. This makes it easier for the wax to seep out of the toner matrix particles because it has moderately low compatibility with resins such as polyesters, which are relatively polar. Examples of long-chain hydrocarbons include aliphatic hydrocarbons having 12 to 34 carbon atoms.

[0082] Examples of waxes include: Esters of monohydric alcohols such as behenyl behenate, stearyl stearate, and palmityl palmitate with aliphatic monocarboxylic acids, or esters of monohydric carboxylic acids with aliphatic monoalcohols; Esters of dihydric alcohols such as dibehenyl sebacate and hexanediol dibehenate with aliphatic monocarboxylic acids, or esters of dihydric carboxylic acids with aliphatic monoalcohols; Esters of trihydric alcohols such as glycerol tribehenate with aliphatic monocarboxylic acids, or esters of trihydric alcohols with aliphatic monoalcohols; Esters of tetrahydric alcohols such as pentaerythritol tetrastearate and pentaerythritol tetrapalmitate with aliphatic monocarboxylic acids, or esters of tetrahydric alcohols with aliphatic monoalcohols; Esters of hexavalent alcohols such as dipentaerythritol hexastearate and dipentaerythritol hexapalmitate with aliphatic monocarboxylic acids, or esters of hexavalent carboxylic acids with aliphatic monoalcohols; Esters of polyhydric alcohols such as polyglycerol behenates with aliphatic monocarboxylic acids, or esters of polyhydric acids with aliphatic monoalcohols; Natural ester waxes such as carnauba wax and rice wax (these are also simply called ester waxes); Ketone waxes such as dibehenyl ketone, diheptadecyl ketone (stearone), distearyl ketone, dieicosyl ketone, dipalmytil ketone, dimyristyl ketone, dilauryl ketone, diheptadecyl ketone, lauryl myristyl ketone, lauryl palmityl ketone, myristyl palmityl ketone, myristyl stearyl ketone, myristyl behenyl ketone, palmityl stearyl ketone, palmityl behenyl ketone, and stearyl behenyl ketone; Higher fatty alcohols, fatty acids such as stearic acid and palmitic acid; Acid amide wax; Low molecular weight crystalline polyesters such as diethylene glycol distearate; These are some examples.

[0083] In addition to the examples given above, if the surface treatment agent has very high hydrophobicity (low HSP2), Paraffin wax, microcrystalline wax, petrolatum and other petroleum-based waxes and their derivatives; Hydrocarbon waxes and their derivatives produced by the Fischer-Tropsch process; Polyolefin waxes such as polyethylene wax and polypropylene wax, and their derivatives (these are also simply called hydrocarbon waxes); It may also be used.

[0084] Among these waxes, paraffin wax, ketone wax, and ester wax are preferred, ketone wax and ester wax are more preferred, ester wax is even more preferred, and ester wax containing two or more ester groups is most preferred.

[0085] The melting point of the wax is preferably 65°C to 90°C from the viewpoint of low-temperature fixation and heat-resistant storage. The melting point is measured using a differential scanning calorimetry device (for example, PerkinElmer's "Diamond DSC"). Specifically, 3.0 mg of wax is sealed in an aluminum pan and set in a holder. An empty aluminum pan is used as a reference. The measurement conditions are a measurement temperature of 0°C to 100°C and a heating rate of 10°C / min, and the melting point can be determined from the data obtained during this heating process.

[0086] The wax content is preferably 7% to 15% by mass, and more preferably 7.5% to 10% by mass, relative to the total mass of the toner matrix particles. Having a wax content within this range tends to improve the fixing separation properties during the fixing process and the heat resistance of the toner during storage.

[0087] 1-2-2. Binding resin The binder resin includes a crystalline polyester resin and an amorphous resin.

[0088] 1-2-2-1. Amorphous resins Examples of amorphous resins include styrene resin, acrylic resin, styrene / acrylic copolymer resin, olefin resin, amorphous polyester resin, polyamide resin, polycarbonate resin, polyether resin, polyvinyl acetate resin, polysulfone resin, epoxy resin, polyurethane resin, and urea resin. Only one of these may be used, or two or more may be used. Among these, from the viewpoint of low-temperature fixability, heat-resistant storage of toner, and improved heat resistance of fixed images, it is preferable to use a resin selected from the group consisting of styrene resin, acrylic resin, styrene / acrylic copolymer resin, and amorphous polyester resin.

[0089] 1-2-2-1-1. Styrene resin, acrylic resin, styrene / acrylic copolymer resin The following monomers can be used as monomers constituting styrene resin, acrylic resin, and styrene / acrylic copolymer resin.

[0090] Examples of monomers include, Styrene monomers such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, and their derivatives; (meth)acrylic acid ester monomers such as methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isopropyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, stearyl (meth)acrylate, lauryl (meth)acrylate, phenyl (meth)acrylate, diethylaminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, and derivatives thereof; Vinyl esters such as vinyl propionate, vinyl acetate, and vinyl benzoate; Vinyl ethers such as vinyl methyl ether and vinyl ethyl ether; Vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone, and vinyl hexyl ketone; N-vinyl compounds such as N-vinylcarbazole, N-vinylindole, and N-vinylpyrrolidone; Vinyl compounds such as vinylnaphthalene and vinylpyridine; (Meth)acrylic acid derivatives such as acrylonitrile, methacrylonitrile, and acrylamide; These are some examples.

[0091] Furthermore, it is preferable to use monomers having ionic dissociation groups such as carboxyl groups, sulfonic acid groups, and phosphate groups as monomers.

[0092] Examples of monomers having ionic dissociation groups include: Monomers having a carboxyl group, such as (meth)acrylic acid, maleic acid, itaconic acid, cinnamic acid, fumaric acid, monoalkyl maleic acid, and monoalkyl itaconic acid; Monomers having sulfonic acid groups, such as styrene sulfonic acid, allyl sulfosuccinic acid, and 2-acrylamido-2-methylpropanesulfonic acid; Monomers having a phosphate group, such as acidophosphooxyethyl methacrylate; These are some examples.

[0093] Polyfunctional monomers may be used as monomers, and cross-linked structures may be formed. Examples of polyfunctional monomers include divinylbenzene, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, and neopentyl glycol di(meth)acrylate.

[0094] As monomers, only one of these may be used, or two or more may be used in combination.

[0095] 1-2-2-1-2. Amorphous polyester resin Amorphous polyester resins are known polyester resins obtained by the polycondensation reaction of a divalent or higher carboxylic acid (polycarboxylic acid) and a divalent or higher alcohol (polyhydric alcohol), and which do not show a clear endothermic peak in differential scanning calorimetry (DSC). Here, a clear endothermic peak specifically refers to a peak whose full width at half maximum (FMAX) is within 15°C when measured at a heating rate of 10°C / min in differential scanning calorimetry (DSC).

[0096] Polycarboxylic acids are compounds that contain two or more carboxyl groups in a single molecule.

[0097] Examples of polycarboxylic acids used to form amorphous polyester resins include: Saturated aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,16-hexadecanedicarboxylic acid, and 1,18-octadecanedicarboxylic acid; Aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, and naphthalenedicarboxylic acid; Unsaturated aliphatic dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, citraconic acid, glutaconic acid, isododecenylsuccinic acid, n-dodecenylsuccinic acid, and n-octenylsuccinic acid; Trivalent or higher polycarboxylic acids such as trimellitic acid, pyromellitic acid, naphthalentricarboxylic acid, naphthalenetetracarboxylic acid, pyrentricarboxylic acid, and pyrenetetracarboxylic acid. These are some examples. These may be used individually or in combination of two or more types.

[0098] Polyhydric alcohols are compounds that contain two or more hydroxyl groups in a single molecule.

[0099] Examples of polyhydric alcohols used to form amorphous polyester resins include: Aliphatic diols such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, and 1,20-eicosanediol; Bisphenols such as bisphenol A and bisphenol F, and alkylene oxide adducts of bisphenols such as ethylene oxide adducts and propylene oxide adducts; Trivalent or higher polyols such as glycerin, pentaerythritol, hexamethylolmelamine, hexaethylolmelamine, tetramethylolbenzoguanamine, and tetraethylolbenzoguanamine; These are some examples.

[0100] These may be used individually or in combination of two or more types.

[0101] 1-2-2-1-3. Properties of amorphous resins The glass transition temperature of amorphous resins is preferably between 30°C and 50°C. Having the glass transition temperature within this range provides a good balance between low-temperature fixability and heat-resistant storage. The glass transition temperature is measured using differential scanning calorimetry (e.g., PerkinElmer's "Diamond DSC"). Specifically, a 3.0 mg sample is sealed in an aluminum pan and set in the holder. An empty aluminum pan is used as the reference. The measurement conditions are a temperature of 0°C to 100°C and a heating rate of 10°C / min, and the data from this heating is used for analysis. The glass transition temperature can be determined by drawing an extension of the baseline before the rise of the first endothermic peak and a tangent line showing the maximum slope between the rise of the first peak and the peak apex.

[0102] The weight-average molecular weight of amorphous resins is preferably 10,000 to 50,000, and more preferably 25,000 to 35,000. Similarly, the number-average molecular weight is preferably 5,000 to 20,000, and more preferably 6,500 to 12,000. When the weight-average molecular weight or number-average molecular weight is above the lower limit, the fixation and separation properties tend to improve. When the weight-average molecular weight or number-average molecular weight is below the upper limit, the low-temperature fixation properties tend to improve. The weight-average molecular weight and number-average molecular weight are values ​​measured by gel permeation chromatography (GPC).

[0103] Specifically, the instrument "HLC-8120GPC" (manufactured by Tosoh Corporation) and the column "TSKguardcolumn+TSKgelSuperHZ-M3" (manufactured by Tosoh Corporation) are used. The measurement conditions are a column temperature of 40°C, tetrahydrofuran (THF) as the carrier solvent, and a carrier solvent flow rate of 0.2 ml / min. The sample to be measured (amorphous resin) is dissolved in tetrahydrofuran to a concentration of 1 mg / ml by dissolving it in an ultrasonic disperser for 5 minutes at room temperature. The tetrahydrofuran solution of the sample to be measured is processed through a membrane filter with a pore size of 0.2 μm. 10 μL of this sample solution is injected into the instrument together with the carrier solvent and detected using a refractive index detector (RI detector). The weight-average molecular weight and number-average molecular weight of the sample to be measured can be calculated as polystyrene equivalent values ​​using a calibration curve prepared using 10 monodisperse polystyrene standard particles.

[0104] The amorphous resin content is preferably 80% to 95% by mass relative to the total mass of the binder resin. Having an amorphous resin content within this range tends to improve fixation, and consequently, the heat resistance of the toner during storage and the heat resistance of the fixed image are enhanced.

[0105] 1-2-2-2. Crystalline polyester resin Crystalline polyester resins are known polyester resins obtained by polycondensation reactions of divalent or higher carboxylic acids (polycarboxylic acids) and divalent or higher alcohols (polyhydric alcohols), and which exhibit a clear melting peak rather than a stepwise endothermic change in differential scanning calorimetry (DSC). Here, a clear endothermic peak specifically refers to a peak whose full width at half maximum (FMAX) is within 15°C when measured at a heating rate of 10°C / min in differential scanning calorimetry (DSC).

[0106] Examples of polycarboxylic acids used to form crystalline polyester resins include: Saturated aliphatic dicarboxylic acids such as succinic acid; Alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; Aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid; Polycarboxylic acids with a valency of 3 or higher, such as trimellitic acid and pyromellitic acid; Alternatively, examples include the anhydrides or C1-C3 alkyl esters of these carboxylic acid compounds. These may be used individually or in combination of two or more.

[0107] Examples of polyhydric alcohols used to form crystalline polyester resins include: Aliphatic diols such as 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, neopentyl glycol, and 1,4-butenediol; Examples include glycerin, pentaerythritol, trimethylolpropane, sorbitol, and other polyhydric alcohols with a valency of three or higher. These may be used individually or in combination of two or more.

[0108] The crystalline polyester content is preferably 5% to 20% by mass relative to the total mass of the binder resin. A content of 5% or more by mass tends to improve low-temperature fixation. A content of 20% or less by mass suppresses the uneven distribution of crystalline polyester within the toner matrix particles, allowing for more uniform melting of the toner matrix particles during the fixing process, thereby improving the effect of suppressing gloss unevenness caused by wax, etc. Furthermore, crystalline polyester is more easily encapsulated within the toner matrix particles during toner manufacturing, and exposure of the crystalline polyester to the surface of the toner matrix particles is suppressed. Typically, crystalline polyester in toner matrix particles has both crystalline and amorphous components, with the amorphous component having a relatively low glass transition temperature. As a result, suppressing the exposure of crystalline polyester to the surface of the toner matrix particles also suppresses the exposure of the amorphous component, which has a relatively low glass transition temperature. This suppresses fusion between toner particles during storage, thereby improving the heat-resistant storage properties of the toner. From the viewpoint of improving low-temperature fixability, the content of crystalline polyester is more preferably 7.5% to 20% by mass, and even more preferably 12.5% ​​to 20% by mass, based on the total mass of the binder resin. Furthermore, from the viewpoint of suppressing uneven gloss, the content of crystalline polyester is more preferably 5% to 17.5% by mass, and even more preferably 5% to 12.5% ​​by mass, based on the total mass of the binder resin.

[0109] The melting point of crystalline polyester is preferably around 65°C to 90°C from the viewpoint of low-temperature fixability and heat-resistant storage. The melting point of crystalline polyester resin is measured as follows: The melting point of crystalline polyester is indicated by the temperature of the peak top of the melting peak, and is measured by differential scanning calorimetry using "DSC7000X" (manufactured by Hitachi-hightech). Specifically, for example, 1.0 mg of the sample (crystalline polyester resin) is sealed in an aluminum pan (KITNO.B0143013), set in the sample holder of "DSC7000X", and the measurement is performed at a temperature of 0 to 100°C with a heating rate of 10°C / min, and the data from the heating can be analyzed.

[0110] The weight-average molecular weight of crystalline polyester is preferably between 5,000 and 30,000, from the viewpoint of easily improving low-temperature fixability and heat-resistant storage properties. The weight-average molecular weight of crystalline polyester resin can be measured in the same manner as the weight-average molecular weight of amorphous resin.

[0111] 1-2-4. Colorants Various known colorants such as carbon black, black iron oxide, dyes, and pigments can be used as colorants.

[0112] Examples of carbon black include channel black, furnace black, acetylene black, thermal black, and lamp black. Examples of black iron oxide include magnetite, hematite, and titanium trioxide. Examples of dyes include CI Solvent Red 1, 49, 52, 58, 63, 111, 122, CI Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, CI Solvent Blue 25, 36, 60, 70, 93, 95, and others. Examples of pigments include CI Pigment Red 5, 48:1, 48:3, 53:1, 57:1, 81:4, 122, 139, 144, 149, 150, 166, 177, 178, 222, 238, 269, CI Pigment Orange 31, 43, CI Pigment Yellow 14, 17, 74, 93, 94, 138, 155, 156, 158, 180, 185, CI Pigment Green 7, CI Pigment Blue 15:3, 60, etc. For obtaining toner of each color, only one type of coloring agent may be used for each color, or two or more types may be used in combination.

[0113] The colorant content is preferably 1% to 10% by mass, and more preferably 2% to 8% by mass, relative to the total mass of the toner matrix particles. When the colorant content is 1% by mass or more, the colorability tends to increase, and sufficient color development is more easily obtained. When the colorant content is 10% by mass or less, the colorant is less likely to be released from the toner matrix particles, adhesion to carriers etc. is suppressed, and the electrostatic charge tends to increase.

[0114] 1-2-5. Characteristics of Toner Base Particles The average particle size of the toner matrix particles is preferably 3 μm to 10 μm, and more preferably 5 μm to 8 μm, in terms of the volume-based median diameter. This average particle size can be controlled by the concentration of the flocculant used during manufacturing, the amount of organic solvent added, the fusion time, the composition of the binder resin, etc. Having the volume-based median diameter within the above range makes it easier to faithfully reproduce, for example, very small dot images at the 1200 dpi level. The volume-based median diameter of the toner is a value measured and calculated using a measuring device that connects a Beckman Coulter "Multisizer 3" to a computer system equipped with data processing software "Software V3.51". Specifically, 0.02 g of the sample is added to 20 mL of surfactant solution (a surfactant solution prepared by diluting a neutral detergent containing surfactant components 10 times with pure water, for example, for the purpose of dispersing toner matrix particles), mixed, and then ultrasonic dispersion is performed for 1 minute to prepare the toner dispersion. This toner dispersion is pipetteed into a beaker containing Beckman Coulter's "ISOTON II" in the sample stand until the concentration displayed on the measuring device reaches 8%. This concentration range makes it easier to obtain reproducible measurements. The measurement conditions are a particle count of 25,000 and an aperture diameter of 100 μm. The measurement range of 2 μm to 60 μm is divided into 256 sections to calculate frequency values, and the particle diameter representing the largest 50% of the volume integral fractions can be considered the volume-based median diameter.

[0115] The average circularity of the toner matrix particles is preferably 0.930 to 1.000, and more preferably 0.950 to 0.995, from the viewpoint of improving the stability of the charging characteristics and low-temperature fixation. When the average circularity is within the above range, individual toner matrix particles are less likely to break down, contamination of the triboelectric charging imparting member is suppressed, and the charging properties of the toner become more stable. Image quality also tends to improve. The average circularity of the toner is a value measured using Sysmex's "FPIA-3000". Specifically, the sample to be measured is soaked in an aqueous solution containing a surfactant, dispersed by ultrasonic dispersion treatment for 1 minute, and then imaged using Sysmex's "FPIA-3000" in HPF (high magnification imaging) mode with an appropriate density of 3000 to 10000 HPF detections. The average circularity is calculated by determining the circularity of each toner matrix particle according to the following formula (y), adding the circularity values ​​of each toner matrix particle, and dividing by the total number of toner matrix particles. If the HPF detection count falls within the above range, reproducibility is more likely to be achieved. Circularity = (Perimeter of a circle with the same projection area as the particle image) / (Perimeter of the particle projection image) Equation (y)

[0116] The toner matrix particles are preferably in a core-shell structure, as this enhances low-temperature fixation and heat-resistant storage properties. The shell layer is not limited to completely covering the core particles; some of the core particle surface may be exposed.

[0117] The components constituting the shell layer are not particularly limited, but amorphous resins such as amorphous polyester resin, styrene resin, acrylic resin, and styrene / acrylic copolymer resin are preferred. The resin content constituting the shell layer is preferably 5% to 30% by mass relative to the total mass of the toner matrix particles.

[0118] 1-3. Others The bulk density of the toner is 0.350 g / cm³. 3 Preferably, it is 0.370 g / cm³ or more. 3 It is more preferable that the amount be greater than or equal to 0.390 g / cm³. 3It is even more preferable that the value be greater than or equal to the above. An upper limit, for example, is 0.450 g / cm³. 3 The following is preferable: Bulk density is a physical property value that indicates the fluidity and packing effect of the toner, and the bulk density is 0.350 g / cm³. 3 When the density is above this level, the packing effect is more easily suppressed, and fluidity is more easily increased. Also, the bulk density is 0.450 g / cm³. 3 The following conditions make it easier to handle the toner when supplying it.

[0119] The bulk density of toner can be determined in the same manner as described in Japanese Patent Publication No. 2014-137518. Specifically, as shown in Figure 1 of Japanese Patent Publication No. 2014-137518, first, a cylindrical container with a capacity of 25 cm³ and a circular opening with a diameter of 28 mm at its upper end is placed on a container stand set on a horizontal surface. A funnel with a discharge port with a diameter of 2.5 mm at its lower end is held by a funnel holder on a stand provided on the container stand, directly above the cylindrical container, at a position where the distance from the opening of the container to the tip of the discharge port of the funnel is 25 mm. Next, the toner to be measured is discharged from the discharge port of the funnel and allowed to fall into the container from the opening until it overflows from the opening of the cylindrical container. After removing the raised sample portion by leveling the toner horizontally along the surface of the opening of the container, the mass of the toner filled in the container is measured. From this measurement, the bulk density of the toner d (g / cm³) is calculated using the following formula (B). 3 ) is required. d = (mass of sample in container (g)) / (volume of container (cm³)) 3 ) Formula (B)

[0120] The 50% agglomeration temperature of the toner is preferably 57.5°C or higher, more preferably 60.0°C or higher, and even more preferably 62.0°C or higher. The upper limit can be, for example, 65.0°C or lower. A 50% agglomeration temperature of 57.5°C or higher tends to improve heat resistance during storage.

[0121] The 50% coagulation temperature of toner can be determined, for example, by the following method: 0.5g of toner is placed in a 10ml glass bottle with an inner diameter of 21mm, the lid is closed, and it is shaken 600 times at room temperature using a Seishin Corporation "Tap Denser KYT-2000". These bottles are then left with the lids removed at three temperature levels (57.5°C, 60.0°C, and 62.5°C) and in a 35% RH environment for 2 hours. Next, the toner is carefully placed on a 48-mesh (350μm opening) sieve, taking care not to disintegrate the toner aggregates, and set in a powder tester (Hosokawa Micron Corporation). The sieve is secured with a retaining bar and knob nut, the vibration intensity is adjusted to a feed width of 1mm, and vibration is applied for 10 seconds. After that, the percentage (mass%) of the remaining toner on the sieve is measured, and the toner coagulation rate is calculated based on the following formula. Toner aggregation rate (%) = Mass of remaining toner on the sieve (g) / 0.5 (g) × 100 The toner coagulation rate is measured at the three temperature levels mentioned above, and the temperature at which the coagulation rate reaches 50% is estimated and defined as the 50% coagulation temperature.

[0122] The minimum fixing temperature of the toner (UO avoidance temperature) is preferably below 140°C, more preferably below 135°C, and even more preferably below 130°C. The lower the minimum fixing temperature, the easier it is to achieve low-temperature fixing performance.

[0123] The minimum fixing temperature in this application is a value that can be determined, for example, by the following method. Prepare a fixing unit of a Konica Minolta "bizhub PRESS® C1070" multifunction printer, modified to allow the surface temperature of the upper fixing belt and lower fixing roller to be changed. The above unit used is one that has been modified to allow free setting of fixing temperature, toner adhesion amount, and system speed. In an environment of normal temperature and humidity (temperature 20℃, humidity 50%RH), set the adhesion amount to 11.3g / m2 on Nippon Paper Industries' "NPI Superior (127.9g / m2)" A4 size fine paper. Then, a fixing experiment is performed to fix a 100mm x 100mm image, repeatedly changing the set fixing temperature from 120℃ to 180℃ in 1℃ increments. The lowest fixing temperature at which no image smudge due to fixing offset is visually confirmed is defined as the minimum fixing temperature (UO avoidance temperature).

[0124] The toner according to this embodiment may be used as a magnetic or non-magnetic one-component developer, or it may be mixed with a carrier and used as a two-component developer.

[0125] When toner is used as a two-component developer, magnetic particles made of conventionally known materials such as metals like iron, ferrite, and magnetite, or alloys of these metals with metals like aluminum and lead, can be used as carriers. Among these, ferrite particles are particularly preferred. In addition, coated carriers, in which the surface of magnetic particles is coated with a coating agent such as resin, or dispersed carriers, in which fine magnetic powder is dispersed in a binder resin, may also be used as carriers.

[0126] The median diameter of the carrier based on volume is preferably 20 μm to 100 μm, and more preferably 25 μm to 80 μm. The median diameter of the carrier based on volume is a value measured by a laser diffraction particle size distribution analyzer equipped with a wet disperser (for example, "HELOS" manufactured by SYMPATEC).

[0127] 2. Toner manufacturing method The method for manufacturing the toner according to this embodiment is not particularly limited, and known methods may be used. Examples of manufacturing methods include grinding, emulsification dispersion, suspension polymerization, dispersion polymerization, emulsion polymerization, and emulsion polymerization agglutination. Among these, emulsion polymerization agglutination is preferred from the viewpoint of manufacturing cost and manufacturing stability.

[0128] In the method for producing toner by emulsion polymerization agglutination, aqueous dispersions containing fine particles of each component are prepared in an aqueous medium, and these aqueous dispersions are mixed. The fine particles of each component then agglutinate and heat-fuse together to form toner matrix particles.

[0129] The binder resin fine particles may have a multilayer structure of two or more layers, each containing a binder resin of a different composition, and can be formed by carrying out polymerization reactions in multiple stages. For example, a two-layer structure can be produced by preparing a dispersion of resin fine particles by first-stage polymerization, adding a polymerization initiator and a polymerizable monomer to this dispersion, and then performing second-stage polymerization.

[0130] Here, an aqueous dispersion refers to a dispersion in which a dispersion (particles) is dispersed in an aqueous medium, and an aqueous medium refers to a medium in which the water content is 50% by mass or more relative to the total mass of the solvent. Components other than water include organic solvents that dissolve in water. Examples of organic solvents that dissolve in water include methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, and tetrahydrofuran. Of these, it is preferable to use alcohol-based organic solvents such as methanol, ethanol, isopropanol, and butanol, which do not dissolve the resin.

[0131] An example of a manufacturing method by emulsion polymerization agglutination is a manufacturing method that includes the following steps. (a) A step of preparing an aqueous dispersion containing fine particles of a binder resin (hereinafter also referred to as "binder resin fine particles") in an aqueous medium, (b) A step of preparing an aqueous dispersion containing colorant fine particles in an aqueous medium. (c) A process of forming aggregated particles by agglomerating and fusing binder resin fine particles and colorant fine particles in an aqueous medium. (d) A process to obtain toner matrix particles by maturing the associated particles with thermal energy to control their shape. (e) A step of cooling the dispersion of toner matrix particles. (f) Crystallization acceleration step: Reheating the cooled toner matrix particle dispersion to promote crystallization. (g) A process of filtering out toner matrix particles from an aqueous medium and removing surfactants and other substances from the toner matrix particles. (h) A step to dry the washed toner matrix particles. (i) Steps to add an external additive to the dried toner matrix particles.

[0132] The above steps (a) to (i) may be performed in their entirety or in their partial form.

[0133] (a) Preparation of an aqueous dispersion of binder resin fine particles In this process, an aqueous dispersion containing fine particles of the binder resin is prepared.

[0134] When the binder resin is a resin synthesized by radical polymerization (e.g., styrene resin, acrylic resin, styrene / acrylic copolymer resin, etc.), the aqueous dispersion of binder resin fine particles can be prepared by miniemulsion polymerization using the monomers exemplified above. The monomers exemplified above are added to an aqueous medium containing a surfactant, mechanical energy is applied to form droplets, and then the polymerization reaction proceeds in the droplets by radicals from a water-soluble radical polymerization initiator. The droplets may also contain an oil-soluble polymerization initiator.

[0135] [Surfactants] In this process, various conventionally known anionic surfactants, cationic surfactants, nonionic surfactants, etc., can be used as surfactants.

[0136] [Polymerization initiator] The polymerization initiator used in this process may be any known initiator. Examples of polymerization initiators include persulfates (potassium persulfate, ammonium persulfate, etc.), azo compounds (4,4'-azobis-4-cyanovaleric acid and its salts, 2,2'-azobis(2-amidinopropane) salt, etc.), peroxide compounds, and azobisisobutyronitrile. Among these, persulfates (potassium persulfate, ammonium persulfate, etc.) are preferred.

[0137] [Chain transfer agent] In this process, known chain transfer agents may be used to adjust the molecular weight of the binder resin. Examples of chain transfer agents include mercaptans such as 2-chloroethanol, octyl mercaptan, dodecyl mercaptan, and t-dodecyl mercaptan, as well as styrene dimers.

[0138] When the binder resin is a resin synthesized by condensation polymerization (for example, a crystalline polyester resin, an amorphous polyester resin, etc.), an aqueous dispersion of binder resin fine particles can be prepared by synthesizing the binder resin and dispersing this binder resin in an aqueous medium in the form of fine particles. Specifically, an oil phase is prepared by dissolving or dispersing the binder resin in an organic solvent. The oil phase is dispersed in an aqueous medium by phase inversion emulsification or the like to form oil droplets with a controlled particle size. Subsequently, by removing the organic solvent, an aqueous dispersion of binder resin fine particles can be prepared.

[0139] The amount of aqueous medium used is preferably 50 to 2000 parts by mass, and more preferably 100 to 1000 parts by mass, per 100 parts by mass of the oil phase liquid.

[0140] A surfactant or the like may be added to the aqueous medium to improve the dispersion stability of the oil droplets. Examples of surfactants include those similar to those listed in the above steps.

[0141] For the preparation of the oil phase liquid, organic solvents with low boiling points and low solubility in water are preferred, from the viewpoint of facilitating removal after the formation of oil droplets. Examples of such organic solvents include methyl acetate, ethyl acetate, methyl ethyl ketone, methyl isobutyl ketone, toluene, and xylene. These may be used individually or in combination of two or more. The amount of organic solvent used can be 1 to 300 parts by mass per 100 parts by mass of amorphous polyester resin.

[0142] Emulsification and dispersion of an oil phase liquid can be carried out using mechanical energy.

[0143] The toner matrix particles according to this embodiment contain wax. In this step, the wax may be dissolved or dispersed in advance in a monomer solution for synthesizing a binder resin formed by radical polymerization or in an oil phase liquid of a binder resin formed by condensation polymerization. This allows the wax to be introduced into the toner matrix particles. Alternatively, the wax can be introduced into the toner matrix particles by preparing a dispersion of wax fine particles containing wax and agglomerating the wax fine particles together with binder resin fine particles and colorant fine particles in the agglomeration and fusion step. Among these, it is preferable to dissolve or disperse the wax in a monomer solution or oil phase liquid beforehand.

[0144] Furthermore, the toner matrix particles according to this embodiment may contain other internal additives, such as charge control agents, as needed. Such internal additives may, for example, be dissolved or dispersed in advance in this step in a monomer solution for synthesizing a binder resin formed by radical polymerization or in the oil phase liquid of a binder resin formed by condensation polymerization. Alternatively, a dispersion of internal additive fine particles containing the internal additive may be prepared separately, and the internal additive fine particles may be aggregated together with the binder resin fine particles and colorant fine particles in the aggregation and fusion step to introduce them into the toner matrix particles. Among these, it is preferable to dissolve or disperse the internal additive in a monomer solution or oil phase liquid beforehand.

[0145] The average particle size of the binder resin fine particles is preferably in the range of 100 nm to 400 nm in terms of volume-based median diameter. The volume-based median diameter of the binder resin fine particles is a value measured using Nikkiso's "Microtrac UPA-150".

[0146] The binder resin comprises at least two resins: a crystalline polyester resin and the amorphous resin. In this case, one type of fine particle containing multiple resins may be prepared, multiple fine particles containing only one type of resin may be prepared, or fine particles containing multiple resins and fine particles containing only one type of resin may be prepared.

[0147] (b) Preparation of an aqueous dispersion of colorant fine particles This step is performed as needed when a toner matrix containing a colorant is desired, and involves dispersing the colorant in a fine particle form in an aqueous medium to prepare an aqueous dispersion of colorant fine particles.

[0148] Aqueous dispersions of colorant fine particles can be obtained by dispersing the colorant in an aqueous medium to which a surfactant is added at a critical micelle concentration (CMC) or higher.

[0149] Dispersion of colorants can be carried out using mechanical energy. Known dispersers can be used, but examples include ultrasonic dispersers, mechanical homogenizers, pressurized dispersers such as Manton-Gorin and pressure homogenizers, sand grinders, and medium-type dispersers such as Getzmann mills and diamond fine mills.

[0150] The volume-based median diameter of the dispersed colorant fine particles is preferably 10 nm to 300 nm, more preferably 100 nm to 200 nm, and even more preferably 100 nm to 150 nm. The volume-based median diameter of the colorant fine particles is a value measured using, for example, the "NANOTRAC Wave II" (manufactured by Microtrac), a particle size measuring device that uses dynamic light scattering.

[0151] (c) Agglomeration / fusion process In this process, binder resin microparticles, colorant microparticles, and, if necessary, other toner component microparticles are aggregated and then fused together by heating.

[0152] Specifically, the above-mentioned fine particles are dispersed in an aqueous medium, and a coagulant at a concentration equal to or greater than the critical coagulation concentration is added to the aqueous dispersion. By raising the temperature to a level above the glass transition point of the amorphous resin, coagulation and fusion are caused.

[0153] The fusion temperature for fusing the binder resin fine particles should be above the glass transition temperature of the binder resin, but is particularly preferably between (glass transition temperature of binder resin + 10°C) and (glass transition temperature of binder resin + 50°C), and especially preferably between (glass transition temperature of binder resin + 15°C) and (glass transition temperature of binder resin + 40°C).

[0154] [Agglutinants] The flocculant used in this process is not particularly limited, but one selected from metal salts such as alkali metal salts and alkaline earth metal salts is preferably used. Examples of metal salts include monovalent metal salts such as sodium, potassium, and lithium; divalent metal salts such as calcium, magnesium, manganese, and copper; and trivalent metal salts such as iron and aluminum. Specific examples of metal salts include sodium chloride, potassium chloride, lithium chloride, calcium chloride, magnesium chloride, zinc chloride, copper sulfate, magnesium sulfate, and manganese sulfate. Among these, it is preferable to use divalent metal salts because they can promote flocculation in smaller amounts. One type may be used, or two or more types may be used in combination.

[0155] When toner matrix particles have a core-shell structure, they can be manufactured, for example, by the following process: Core particles are formed by aggregating and fusing binder resin microparticles and colorant microparticles. Then, toner matrix particles having a core-shell structure can be formed by aggregating and fusing shell resin microparticles, which are used to form the shell layer, onto the core particles.

[0156] (d) Aging process This process is performed as needed, and in this maturation process, the toner matrix particles obtained in the aggregation and fusion process are matured using thermal energy until they reach the desired shape, thereby forming the toner matrix particles.

[0157] The maturation process can be carried out by heating and stirring the system in which the aggregated particles are dispersed, and adjusting the heating temperature, stirring speed, heating time, etc., until the shape of the aggregated particles reaches the desired degree of circularity.

[0158] (e) Cooling process This step involves cooling the dispersion of toner matrix particles. Preferably, the cooling process should be performed at a cooling rate of 1°C / min to 20°C / min. Examples of cooling methods include introducing a refrigerant from outside the reaction vessel or directly adding chilled water to the reaction system.

[0159] (f) Heat treatment process This process promotes the crystallization of the crystalline resin in the toner matrix particles. The heat treatment conditions are preferably such that the temperature is above the glass transition temperature of the binder resin and within the range of -5°C from the melting point of the crystalline resin for 30 minutes or more.

[0160] (g) Filtration and washing process This process involves separating the cooled toner matrix particles from a dispersion of toner matrix particles using a solid-liquid separation method, and then cleaning the toner cake (an aggregate of wet toner matrix particles formed into a cake-like structure) obtained through solid-liquid separation by removing any attached substances such as surfactants and flocculants.

[0161] For solid-liquid separation, various methods can be used without particular limitation, including centrifugal separation, vacuum filtration using a Nutsch filter, and filtration using a filter press. Furthermore, during washing, it is preferable to wash with water until the electrical conductivity of the filtrate reaches 10 μS / cm.

[0162] (h) Drying process This step involves drying the washed toner cake and can be carried out in the same manner as the drying step in known methods for producing toner matrix particles.

[0163] Examples of dryers used for drying toner cakes include spray dryers, vacuum freeze dryers, and reduced-pressure dryers. It is preferable to use stationary shelf dryers, mobile shelf dryers, fluidized bed dryers, rotary dryers, or agitated dryers.

[0164] The moisture content of the dried toner matrix particles is preferably 5% by mass or less, and more preferably 2% by mass or less. If the dried toner matrix particles are agglomerated by weak interparticle attractive forces, the aggregates may be subjected to a crushing treatment. Examples of crushing treatment devices include mechanical crushing devices such as jet mills, Henschel mixers, coffee mills, and food processors.

[0165] (i) Addition of external additives This process involves adding an external additive to the toner matrix particles.

[0166] The toner matrix particles described above may be externally supplemented with inorganic particles that have been surface-treated with a surface treatment agent, and may also be supplemented with, for example, fluidizers, cleaning aids, etc., to improve fluidity, chargeability, cleaning properties, etc., and are not particularly limited.

[0167] The amount of these external additives added is preferably 0.3 to 3.0 parts by mass, and more preferably 1.0 to 2.0 parts by mass, per 100 parts by mass of toner matrix particles.

[0168] Mechanical mixing devices such as Henschel mixers and coffee grinders can be used for mixing external additives.

[0169] Although the embodiments have been described in detail above, the invention is not limited to the examples described above, and various modifications may be made. [Examples]

[0170] The present invention will be described below with reference to examples. The scope of the present invention is not to be limited by the examples.

[0171] 1. Prepare the materials The inorganic particles and surface treatment agents shown below were prepared.

[0172] 1-1. Preparation of inorganic particles AEROSIL40: Fumed silica with a particle size of 100 nm, manufactured by Nippon Aerosil Co., Ltd., product name "AEROSIL40 (registered trademark)". AEROSIL50: Fumed silica with a particle size of 30 nm, manufactured by Nippon Aerosil Co., Ltd., product name "AEROSIL50 (registered trademark)". AEROSIL200: Fumed silica with a particle size of 12 nm: Manufactured by Nippon Aerosil Co., Ltd., product name "AEROSIL200 (registered trademark)"

[0173] The above particle size was obtained by arithmetic mean taking the particle diameters of 1000 randomly selected particles observed using a transmission electron microscope (TEM).

[0174] 1-2. Preparation of surface treatment agent [Reactive silicone oil] DMO-SiOH1: A reactive silicone oil with hydroxyl groups at both ends of a poly(dimethylsiloxane) molecule (weight-average molecular weight 7000). DMO-SiOH2: A reactive silicone oil with hydroxyl groups at both ends of a poly(dimethylsiloxane) molecule (weight-average molecular weight 1200). DMO-SiOH3: A reactive silicone oil with hydroxyl groups at both ends of a poly(dimethylsiloxane) molecule (weight-average molecular weight 19000).

[0175] [Non-reactive silicone oil] PDMS: Poly(dimethylsiloxane), weight-average molecular weight 7000

[0176] [Surface treatment agents other than silicone oil] HMDS: Hexamethyldisilazane, molecular weight 162 Octyltrimethoxysilane: Molecular weight 234

[0177] The weight-average molecular weights of reactive and non-reactive silicone oils were measured by gel permeation chromatography (GPC). Specifically, the instrument "HLC-8120GPC" (Tosoh Corporation) and the column "TSKguardcolumn + TSKgelSuperHZ-M3" (Tosoh Corporation) were used. The measurement conditions were a column temperature of 40°C, tetrahydrofuran (THF) as the carrier solvent, and a carrier solvent flow rate of 0.2 ml / min. The sample was dissolved in tetrahydrofuran to a concentration of 1 mg / ml under dissolution conditions where it was treated with an ultrasonic disperser for 5 minutes at room temperature. The tetrahydrofuran solution of the sample was processed through a membrane filter with a pore size of 0.2 μm. 10 μL of this sample solution was injected into the instrument along with the carrier solvent and detected using a refractive index detector (RI detector). The weight-average molecular weight of the sample was calculated as a polystyrene equivalent value using a calibration curve prepared with 10 monodisperse polystyrene standard particles.

[0178] 2. Preparation of external additives (surface-treated inorganic particles) External additives 1 to 10 were prepared as shown below. Table 1 shows a list of their formulations, manufacturing methods, and properties.

[0179] [Preparation of external additive 1] 100 parts by weight of AEROSIL50 were placed in a reactor, and under a nitrogen gas atmosphere and stirring, DMO-SiOH1, diluted with hexane as shown in Table 5, was introduced in the ratio shown in Table 1, and the surface treatment was carried out while stirring continued. To break the loose aggregation of the surface-treated silica, it was finally crushed using a sample mill (manufactured by Nara Machine Works Co., Ltd.). In this way, external additive 1 was obtained.

[0180] [Preparation of external additive 2] External additive 2 was obtained in the same manner as external additive 1, except that the type of surface treatment agent was changed to PDMS, the amount added was changed to 3 parts by mass, the reaction temperature for surface treatment was changed to 280°C, and the reaction time was changed to 30 minutes.

[0181] [Preparation of external additive 3] Except for changing the reaction temperature for the surface treatment to 340°C, external additive 3 was obtained in the same manner as external additive 1.

[0182] [Preparation of external additive 4] Except for changing the type of surface treatment agent to DMO-SiOH2, external additive 4 was obtained in the same manner as external additive 1.

[0183] [Preparation of external additive 5] Except for changing the type of surface treatment agent to DMO-SiOH3, external additive 5 was obtained in the same manner as external additive 1.

[0184] [Preparation of external additive 6] External additive 6 was obtained in the same manner as external additive 1, except that the type of inorganic particles was changed to AEROSIL40 and the amount of surface treatment agent added was changed to 5 parts by mass.

[0185] [Preparation of external additive 7] External additive 7 was obtained in the same manner as external additive 1, except that the type of inorganic particles was changed to AEROSIL200 and the amount of surface treatment agent added was changed to 10 parts by mass.

[0186] [Preparation of external additive 8] External additive 8 was obtained in the same manner as external additive 1, except that the type of surface treatment agent was changed to HMDS, the amount added was changed to 4 parts by mass, and the reaction time was changed to 100 minutes.

[0187] [Preparation of external additive 9] External additive 9 was obtained in the same manner as external additive 1, except that the type of surface treatment agent was changed to octyltrimethoxysilane, the amount added was changed to 4 parts by mass, and the reaction time was changed to 150 minutes.

[0188] [Preparation of external additive 10] External additive 10 was obtained in the same manner as external additive 1, except that the amount of surface treatment agent added was changed to 2 parts by mass, the reaction temperature for surface treatment was changed to 280°C, and the reaction time was changed to 20 minutes.

[0189] [Calculation of HSP values ​​for each external additive (surface-treated inorganic particles)] The HSP value (HSP2) of the surface treatment agent was calculated using Hansen's method as follows. Using HSPiP (Ver. 6.0.04), the Hansen solubility parameters (δD, δP, δH) of each compound were calculated by inputting the chemical structure of the compound to be calculated using the linear molecular notation Smiles equation. From these values, (δD 2 +δP 2 +δH 2 ) 0.5 The HSP value (HSP2) of each compound was calculated through this process.

[0190] [Measurement of the hydrophobicity of each external additive (surface-treated inorganic particles)] 1.0 g of surface-treated inorganic particles was weighed into a 200 mL separatory funnel, and 100 mL of pure water was added to it. The mixture was then shaken in a turbler mixer for 10 minutes. After shaking, it was allowed to stand for 10 minutes, and 20-30 mL of the lower layer of liquid was withdrawn from the funnel. The lower layer of liquid was then separated into a quartz cell with a path length of 10 mm. Using pure water as a blank, the transmittance of light at a wavelength of 500 mm was measured with a colorimeter and defined as the hydrophobicity rate.

[0191] [Measurement of the free silicone oil content of each external additive (surface treatment inorganic particles)] Using a Soxhlet extraction apparatus manufactured by BUCHI, 0.5 g of surface-treated inorganic particles were placed in a cylindrical filter paper with a diameter of 28 mm. Hexane was used as the extraction solvent, and the free silicone oil was extracted from the surface-treated inorganic particles under the conditions of extraction time of 60 minutes and rinsing time of 30 minutes. The carbon content of the surface-treated inorganic particles before and after extraction was measured using an "EMIA-110" manufactured by HORIBA, Ltd. The content of free silicone oil relative to the total amount of surface-treated inorganic particles was calculated by subtracting the carbon content of the surface-treated inorganic particles after extraction and removal of free silicone oil from the carbon content of the surface-treated inorganic particles before extraction.

[0192] [Table 1]

[0193] 3. Preparation of toner matrix particles 3-1. Preparation of a dispersion of binder resin fine particles containing amorphous resin that constitutes the core. [Preparation of binder resin fine particle dispersion 1] (First stage polymerization) A 5L reaction vessel equipped with a stirrer, temperature sensor, condenser, and nitrogen introduction device was prepared by dissolving 8g of sodium dodecyl sulfate in 3L of deionized water. While stirring at a stirring speed of 230rpm under a nitrogen flow, the internal temperature was raised to 80°C, and then a solution of 10g of potassium persulfate dissolved in 200g of deionized water was added. The liquid temperature was then raised again to 80°C, and monomers consisting of 480g of styrene, 250g of n-butyl acrylate, and 68g of methacrylic acid were added dropwise over 1 hour. Polymerization was carried out by heating and stirring at 80°C for 2 hours to obtain a resin fine particle dispersion (a1).

[0194] (Second stage polymerization) A 5L reaction vessel equipped with a stirrer, temperature sensor, cooling tube, and nitrogen introduction device was prepared by dissolving 9.2g of sodium dodecyl ether sulfate in 1500ml of deionized water. After heating this to 98°C, 210.5g of the above-mentioned resin fine particles (a1), a monomer solution consisting of 241g of styrene, 75.0g of 2-ethylhexyl acrylate, and 32.0g of an 80% solution of methacrylic acid, and a mixture prepared by dissolving and mixing 3.9g of n-octyl mercaptan and 104g of behenyl behenate at 90°C were added. The mixture was then mixed and dispersed for 1 hour using a mechanical disperser with a circulation path, "CLEARMIX" manufactured by M-Technique, to prepare a dispersion containing emulsion particles (oil droplets). Next, an initiator solution prepared by dissolving 4.5 g of potassium persulfate in 85 ml of deionized water was added to this dispersion, and polymerization was carried out by heating and stirring the system at 84°C for 1 hour to obtain a resin fine particle dispersion (a2).

[0195] (Third stage polymerization) A solution of 5.3 g of potassium persulfate dissolved in 115 ml of deionized water was added to the above resin microparticles (a2). A mixture of a monomer solution consisting of 368.3 g of styrene, 149.1 g of n-butyl acrylate, and 45 g of an 80% solution of methacrylic acid, and 7.0 g of n-octyl mercaptan was added dropwise over 1 hour under a temperature of 82°C. After the addition was complete, polymerization was carried out by heating and stirring for 2 hours, and then cooled to 28°C to prepare a binder resin microparticle dispersion 1 containing styrene / acrylic copolymer resin.

[0196] These binder resin microparticles had a volume-based median diameter of 220 nm, a weight-average molecular weight of 30,000, a glass transition temperature of 45°C, and a solid content of 30%.

[0197] [Preparation of binder resin fine particle dispersion 2] In the second polymerization step of the preparation process for binder resin particle dispersion 1, binder resin particle dispersion 2 was obtained in the same manner as before, except that the type of wax was changed to paraffin wax (HNP-0190 manufactured by Nippon Seiro Co., Ltd.).

[0198] These binder resin microparticles had a volume-based median diameter of 230 nm, a weight-average molecular weight (Mw) of 30,000, a glass transition temperature of 45°C, and a solid content of 30%.

[0199] [Preparation of binder resin fine particle dispersion 3] In the second polymerization step of the preparation process for binder resin fine particle dispersion 1, binder resin fine particle dispersion 3 was obtained in the same manner except that the type of wax was changed to diheptadecylketone.

[0200] These binder resin microparticles had a volume-based median diameter of 230 nm, a weight-average molecular weight (Mw) of 30,000, a glass transition temperature of 45°C, and a solid content of 30%.

[0201] [Preparation of binder resin fine particle dispersion 4] In the second polymerization step of the preparation process for binder resin fine particle dispersion 1, binder resin fine particle dispersion 4 was obtained in the same manner except that the type of wax was changed to stearyl stearamide.

[0202] These binder resin microparticles had a volume-based median diameter of 220 nm, a weight-average molecular weight (Mw) of 30,000, a glass transition temperature of 45°C, and a solid content of 30%.

[0203] [Preparation of binder resin fine particle dispersion 5] In the second polymerization step of the preparation process for binder resin fine particle dispersion 1, binder resin fine particle dispersion 5 was obtained in the same manner except that the type of wax was changed to pentaerythritol tetrabehenate.

[0204] These binder resin microparticles had a volume-based median diameter of 220 nm, a weight-average molecular weight (Mw) of 30,000, a glass transition temperature of 45°C, and a solid content of 30%.

[0205] [Method for measuring the median diameter of binder resin microparticles based on volume] The volume-based median diameter of the binder resin microparticles was measured using the "Microtrac UPA-150" manufactured by Nikkiso Co., Ltd.

[0206] [Method for measuring the weight-average molecular weight of binder resins] The weight-average molecular weight of the binder resin was measured by gel permeation chromatography (GPC). Specifically, the instrument "HLC-8120GPC" (Tosoh Corporation) and the column "TSKguardcolumn+TSKgelSuperHZ-M3" (Tosoh Corporation) were used. The measurement conditions were a column temperature of 40°C, tetrahydrofuran (THF) as the carrier solvent, and a carrier solvent flow rate of 0.2 ml / min. The sample was dissolved in tetrahydrofuran to a concentration of 1 mg / ml under dissolution conditions where it was treated with an ultrasonic disperser for 5 minutes at room temperature. The tetrahydrofuran solution of the sample was processed through a membrane filter with a pore size of 0.2 μm. 10 μL of this sample solution was injected into the instrument together with the carrier solvent and detected using a refractive index detector (RI detector). The weight-average molecular weight of the sample was calculated as a polystyrene equivalent value using a calibration curve prepared with 10 monodisperse polystyrene standard particles.

[0207] [Method for measuring the glass transition temperature of binder resins] The glass transition point was measured using differential scanning calorimetry (e.g., PerkinElmer's "Diamond DSC"). A 3.0 mg sample was sealed in an aluminum pan and set in a holder. An empty aluminum pan was used as the reference. The measurement conditions were a temperature of 0°C to 100°C and a heating rate of 10°C / min, and the data from this heating stage was used for analysis. The glass transition point was defined as the intersection of the extension of the baseline before the rise of the first endothermic peak and the tangent line showing the maximum slope from the rise of the first peak to the peak apex.

[0208] [Calculation of HSP value of wax contained in binder resin microparticles] The HSP value (HSP1) of the surface treatment agent was calculated in the same way as the HSP value (HSP2) of the wax.

[0209] 3-2. Preparation of a dispersion of binder resin fine particles containing amorphous resin that constitutes the shell portion (hereinafter also referred to as "shell resin fine particle dispersion") [Preparation of resin microparticle dispersion 1 for shells] (Synthesis of amorphous polyester resin) In a reaction vessel equipped with a stirrer, nitrogen inlet tube, temperature sensor, and rectification column, 85 parts by mass of terephthalic acid and 18 parts by mass of fumaric acid were prepared as polycarboxylic acids, and 187 parts by mass of bisphenol A propylene oxide adduct was prepared as a polyhydric alcohol. The temperature of the reaction system was raised to 190°C over 1 hour, and after confirming that the reaction system was uniformly stirred, Ti(OBu)4 was added as a catalyst in an amount of 0.006% by mass relative to the total amount of polycarboxylic acid. Furthermore, while distilling off the water produced, the temperature of the reaction system was raised from the same temperature to 240°C over 6 hours, and then 32.3 parts by mass of stearyl alcohol, which had undergone polymerization by continuing the dehydration condensation reaction at 240°C for 6 hours, was added, and the reaction was carried out at atmospheric pressure at 200°C for 1.5 hours to obtain amorphous polyester resin 1. This amorphous polyester resin 1 had a weight-average molecular weight of 20,000 and a glass transition temperature of 60°C.

[0210] (Preparation of resin particle dispersion 1 for shells) 1200 parts by mass of amorphous polyester resin was dissolved in 200 parts by mass of ethyl acetate. While stirring this solution, an aqueous solution prepared by dissolving sodium polyoxyethylene lauryl ether sulfate in 800 parts by mass of deionized water to a concentration of 1% by mass was added dropwise. After removing the ethyl acetate from this solution under reduced pressure, the pH of the solution was adjusted to 8.5 with ammonia. Subsequently, the solid content concentration was adjusted to 20% by mass. This prepared a dispersion of resin microparticles for shells, in which amorphous polyester resin was dispersed in an aqueous medium. The volume-based median diameter of the above dispersion of resin microparticles for shells was 130 nm.

[0211] [Method for measuring the physical properties of resin microparticles for shells] The weight-average molecular weight, glass transition temperature, and volume-based median diameter of the shell resin microparticles were measured using the same method as for the various properties of the binder resin.

[0212] 3-3. Preparation of a dispersion of binder resin fine particles containing crystalline polyester resin (hereinafter also referred to as "crystalline polyester resin fine particle dispersion") [Preparation of crystalline polyester resin fine particle dispersion 1] (Synthesis of crystalline polyester resin 1) In a 5 L reaction vessel equipped with a stirrer, temperature sensor, condenser, and nitrogen introduction device, 153 parts by mass of dodecanediol as a polycarboxylic acid and 60 parts by mass of 1,4-butanediol as a polyhydric alcohol were prepared. While stirring, the internal temperature was raised to 190°C over 1 hour. After confirming that the mixture was uniformly stirred, Ti(OBu)4 was added as a catalyst in an amount of 0.003% by mass relative to the amount of polycarboxylic acid charged. Subsequently, while distilling off the generated water, the internal temperature was raised from 190°C to 240°C over 6 hours. Polymerization was then carried out by continuing the dehydration condensation reaction at a temperature of 240°C for another 6 hours to obtain crystalline polyester resin 1. This crystalline polyester resin 1 had a melting point of 72°C and a weight-average molecular weight of 15,000.

[0213] (Preparation of crystalline polyester resin fine particle dispersion 1) 1200 parts by mass of crystalline polyester resin was dissolved in 200 parts by mass of ethyl acetate. While stirring this solution, an aqueous solution prepared by dissolving sodium polyoxyethylene lauryl ether sulfate in 800 parts by mass of deionized water to a concentration of 1% by mass was added dropwise. After removing the ethyl acetate from this solution under reduced pressure, the pH of the solution was adjusted to 8.5 with ammonia. Subsequently, the solid content concentration was adjusted to 20% by mass. This prepared a crystalline polyester resin fine particle dispersion 1 in which fine particles of crystalline polyester resin 1 were dispersed in an aqueous medium. The volume-based median diameter of the fine particles of crystalline polyester resin 1 was 200 nm.

[0214] [Method for measuring the melting point of crystalline polyester resin fine particles] The melting point of the crystalline polyester resin was measured as follows: The temperature at the peak top of the melting peak was indicated, and the melting point was measured by differential scanning calorimetry using a "DSC7000X" (manufactured by Hitachi-hightech). Specifically, the melting point was determined by sealing a 1.0 mg sample in an aluminum pan (KITNO.B0143013), setting it in the sample holder of the "DSC7000X," and heating it at a temperature of 0 to 100°C at a heating rate of 10°C / min. The value was then analyzed based on the data obtained during this heating process.

[0215] [Methods for measuring other physical properties of crystalline polyester resin fine particles] The weight-average molecular weight of the crystalline polyester resin and the volume-based median diameter of the crystalline polyester resin fine particles were measured using the same method as for the various physical properties of the binder resin.

[0216] 3-4. Preparation of a dispersion of colorant microparticles 90 parts by mass of sodium dodecyl sulfate were added to 1600 parts by mass of deionized water. While stirring this solution, 420 parts by mass of carbon black (Regal 330R: manufactured by Cabot) were gradually added. Subsequently, a dispersion of colorant fine particles was prepared by dispersing the mixture using a stirring device, "Clearmix" manufactured by M-Technique Co., Ltd. The average particle size (median diameter by volume) of the colorant fine particles was 110 nm.

[0217] [Method for measuring the median diameter of colorant microparticles based on volume] The volume-based median diameter of the colorant microparticles was measured using the "NANOTRAC Wave II" (manufactured by Microtrac), a particle size measurement device that employs dynamic light scattering.

[0218] 3-5. Preparation of toner matrix particles Toner matrix particles 1 to 8 were prepared as shown below. A list of their compositions is shown in Table 2.

[0219] [Preparation of toner matrix particles 1] In a Erlenmeyer flask equipped with a stirring device, a temperature sensor, a cooling pipe, and a nitrogen introduction device, 1600 parts by mass of a binder resin fine particle dispersion liquid 1, 300 parts by mass of a crystalline polyester resin fine particle dispersion liquid 1, 1500 parts by mass of ion-exchanged water, and 500 parts by mass of a colorant fine particle dispersion liquid were prepared. After adjusting the liquid temperature to 25 °C, an aqueous sodium hydroxide solution with a concentration of 25% by mass was added to adjust the pH to 10.

[0220] Next, an aqueous solution in which 54.3 parts by mass of magnesium chloride hexahydrate was dissolved in 54.3 parts by mass of ion-exchanged water was added. Thereafter, by raising the temperature of the system to 97 °C, the aggregation reaction of each resin fine particle and the colorant fine particle was started.

[0221] After the start of this aggregation reaction, sampling was performed regularly, and the volume-based median diameter of the particles was measured using the "Coulter Multisizer 3" manufactured by Beckman Coulter, a particle size distribution measuring device, and aggregation was carried out while continuing stirring until the volume-based median diameter reached 6.3 μm.

[0222] Next, 300 parts by mass of a shell resin fine particle dispersion liquid 1 was added to attach a shell to the surface of the core particles.

[0223] Thereafter, an aqueous solution in which 11.5 parts by mass of sodium chloride was dissolved in 46 parts by mass of ion-exchanged water was added. The temperature of the system was set to 95 °C and stirring was continued for 4 hours. When the circularity reached 0.946 in the measurement by the "FPIA-2100" manufactured by Sysmex, a flow-type particle image analyzer, the reaction was stopped by cooling to 25 °C under the condition of 6 °C / min.

[0224] After cooling, the dispersion liquid of the toner mother particles was heated again to 60 °C under the condition of 6 °C / min and held for 3 hours to promote the crystallization of the crystalline polyester. Thereafter, the reaction was stopped by cooling under the condition of 6 °C / min to obtain a dispersion liquid of the toner mother particles.

[0225] The particle diameter of the toner mother particles after cooling was 6.1 μm and the circularity was 0.970.

[0226] The dispersion of toner matrix particles obtained in this manner was subjected to solid-liquid separation using a basket-type centrifuge, "MARK III, Model No. 60×40," manufactured by Matsumoto Machinery Co., Ltd., to form a wet cake. This wet cake was subjected to repeated washing and solid-liquid separation in the basket-type centrifuge until the electrical conductivity of the filtrate reached 15 μS / cm. Subsequently, the wet cake was dried using a "Flash Jet Dryer" manufactured by Seishin Enterprise Co., Ltd., by blowing an airflow at a temperature of 40°C and a humidity of 20% RH until the moisture content was reduced to 0.5 mass%. By cooling to 24°C, toner matrix particles 1 were obtained. These toner matrix particles 1 had a volume-based median diameter of 6.1 μm and an average circularity of 0.970.

[0227] [Preparation of toner matrix particles 2] Toner matrix particles 2 were obtained in the same manner as toner matrix particles 1, except that the binder resin particle dispersion was changed to binder resin particle dispersion 2. The particle size of the toner particles was 6.1 μm and the circularity was 0.968.

[0228] [Preparation of toner matrix particles 3] Toner matrix particles 3 were obtained in the same manner as toner matrix particles 1, except that the binder resin particle dispersion was changed to binder resin particle dispersion 3. The particle size of the toner matrix particles was 6.2 μm and the circularity was 0.968.

[0229] [Preparation of toner matrix particles 4] Except for changing the binder resin fine particle dispersion to binder resin fine particle dispersion 4, toner matrix particles 4 were obtained in the same manner as toner matrix particles 1. The particle size of the toner particles was 6.1 μm and the circularity was 0.968.

[0230] [Preparation of toner matrix particles 5] Except for changing the binder resin fine particle dispersion to binder resin fine particle dispersion 5, toner matrix particles 5 were obtained in the same manner as toner matrix particles 1. The particle size of the toner particles was 6.1 μm and the circularity was 0.968.

[0231] [Preparation of toner matrix particles 6] Toner matrix particles 6 were obtained in the same manner as toner matrix particles 1, except that the amount of binder resin fine particle dispersion 1 added was changed to 1690 g and the amount of crystalline polyester resin fine particle dispersion 1 added was changed to 165 g. The particle size of the toner particles was 6.1 μm and the circularity was 0.968.

[0232] [Preparation of toner matrix particles 7] Toner matrix particles 7 were obtained in the same manner as toner matrix particles 1, except that the amount of binder resin fine particle dispersion 1 added was changed to 1410 g and the amount of crystalline polyester resin fine particle dispersion 1 added was changed to 585 g. The particle size of the toner particles was 6.1 μm and the circularity was 0.968.

[0233] [Preparation of toner matrix particles 8] Toner matrix particles 8 were obtained in the same manner as toner matrix particles 1, except that the amount of binder resin fine particle dispersion 1 added was changed to 1800 g and the amount of crystalline polyester resin fine particle dispersion 1 added was changed to 0 g. The particle size of the toner particles was 6.1 μm and the circularity was 0.968.

[0234] [Method for measuring the particle size of toner matrix particles] The volume-based median diameter of the toner was measured and calculated using a measuring device consisting of a Beckman Coulter "Multisizer 3" connected to a computer system equipped with data processing software "Software V3.51". Specifically, 0.02 g of the sample was added to 20 mL of surfactant solution (a surfactant solution prepared by diluting a neutral detergent containing surfactant components 10 times with pure water for the purpose of dispersing toner matrix particles), mixed, and then ultrasonically dispersed for 1 minute to prepare the toner dispersion. The toner dispersion was then pipetted into a beaker containing a Beckman Coulter "ISOTON II" in the sample stand until the concentration indicated on the measuring device reached 8%. The measurement conditions were a particle count of 25,000 and an aperture diameter of 100 μm. The measurement range of 2 μm to 60 μm was divided into 256 sections, and frequency values ​​were calculated. The particle diameters of the top 50% of the volume integrated fractions were defined as the volume-based median diameter.

[0235] [Method for Measuring Roundness of Toner Mother Particles] The average roundness of the toner is the value measured using the "FPIA-3000" manufactured by Sysmex Corporation. Specifically, after allowing the measurement sample to conform to an aqueous solution containing a surfactant and performing ultrasonic dispersion treatment for 1 minute for dispersion, imaging was performed at an appropriate concentration of 3000 to 10000 HPF detection counts in the measurement condition HPF (high magnification imaging) mode using the "FPIA-3000" manufactured by Sysmex Corporation. The average roundness is a value calculated by calculating the roundness of each toner mother particle according to the following formula (y), adding the roundness of each toner mother particle, and dividing by the total number of toner mother particles. Roundness = (Perimeter of a circle having the same projected area as the particle image) / (Perimeter of the particle projection image) Formula (y)

[0236] [Table 2]

[0237] 4. Preparation of Toner [Preparation of Toner 1] To 100 parts by mass of toner mother particle 1, 1.50 parts by mass of external additive 1 and 0.20 parts by mass of external additive 2 were added. Using a Henschel mixer, mixing was carried out for 20 minutes under the condition of a peripheral speed of the rotating blade of 40 m / s, and further passed through a 400-mesh sieve to obtain toner 1.

[0238] [Preparation of Toner 2] Toner particle 2 was obtained in the same manner as toner 1, except that the toner mother particle was changed to toner mother particle 2.

[0239] [Preparation of Toner 3] Toner particle 3 was obtained in the same manner as toner 1, except that the toner mother particle was changed to toner mother particle 3.

[0240] [Preparation of Toner 4] Toner 4 was obtained in the same manner as toner 1, except that the toner matrix particles were changed to toner matrix particles 4 and the external additive 8 was changed to external additive 9.

[0241] [Preparing Toner 5] Toner 5 was obtained in the same manner as toner 4, except that the toner matrix particles were changed to toner matrix particles 5.

[0242] [Preparing Toner 6] Toner 6 was obtained in the same manner as toner 4, except that external additive 1 was changed to external additive 2.

[0243] [Preparing Toner 7] Toner 7 was obtained in the same manner as toner 4, except that external additive 1 was changed to external additive 3.

[0244] [Preparing Toner 8] Toner 8 was obtained in the same manner as toner 4, except that external additive 1 was changed to external additive 4.

[0245] [Preparing Toner 9] Toner 9 was obtained in the same manner as toner 4, except that external additive 1 was changed to external additive 5.

[0246] [Preparing Toner 10] Toner 10 was obtained in the same manner as toner 4, except that toner matrix particles 4 were changed to toner matrix particles 6.

[0247] [Preparing Toner 11] Toner 11 was obtained in the same manner as toner 4, except that toner matrix particles 4 were changed to toner matrix particles 7.

[0248] [Preparing Toner 12] Toner 12 was obtained in the same manner as toner 4, except that external additive 1 was changed to external additive 6.

[0249] [Preparation of Toner 13] Toner 13 was obtained in the same manner as toner 4, except that external additive 1 was changed to external additive 7.

[0250] [Preparation of Toner 14] Toner 14 was obtained in the same manner as toner 4, except that the amount of external additive 1 added was changed to 0.70 parts by mass.

[0251] [Preparing Toner 15] Toner 15 was obtained in the same manner as toner 4, except that the amount of external additive 1 added was changed to 2.00 parts by mass.

[0252] [Preparing Toner 16] Toner 16 was obtained in the same manner as toner 4, except that the amount of external additive 1 added was changed to 0.25 parts by mass.

[0253] [Preparing Toner 17] Toner 17 was obtained in the same manner as toner 4, except that the amount of external additive 1 added was changed to 3.00 parts by mass.

[0254] [Preparing Toner 18] Toner 18 was obtained in the same manner as toner 2, except that the amount of external additive 1 was changed to 0.20 parts by mass and the amount of external additive 8 was changed to 1.50 parts by mass.

[0255] [Preparation of Toner 19] Toner 19 was obtained in the same manner as toner 18, except that external additive 8 was changed to external additive 9.

[0256] [Preparation of Toner 20] Toner 20 was obtained in the same manner as toner 18, except that external additive 8 was changed to external additive 10.

[0257] [Preparation of Toner 21] Toner 21 was obtained in the same manner as toner 4, except that toner matrix particles 4 were changed to toner matrix particles 8.

[0258] 5. Preparation of the developer Developers 1 to 21 were prepared by adding a ferrite carrier with a volume-based median diameter of 60 μm, coated with silicone resin, to each of the toners 1 to 21 so that the toner concentration was 6% by mass, and then mixing them in a V-type mixer.

[0259] 6. Evaluation The following evaluations were conducted on toner cartridges 1 through 21. The results are shown in Table 3 below.

[0260] 6-1. Evaluation of low-temperature fixation properties / UO The fuser unit of the Konica Minolta "bizhub PRESS® C1070" multifunction printer was modified to allow for adjustment of the surface temperature of the upper fuser belt and lower fuser roller. The modified unit allowed for free setting of the fuser temperature, toner amount, and system speed.

[0261] Under normal temperature and humidity conditions (temperature 20°C, humidity 50%RH), the NPI high-quality paper (127.9g / m²) manufactured by Nippon Paper Industries, A4 size, was tested. 2 The amount of adhesion on the surface was 11.3 g / m². 2 The temperature was then set to 120°C. Subsequently, fixing experiments were repeatedly conducted to fix 100mm x 100mm images, increasing the set fixing temperature in 1°C increments from 120°C up to 180°C. The lowest fixing temperature at which no image smudge due to fixing offset was visually observed was defined as the minimum fixing temperature (UO avoidance temperature). It was shown that a lower minimum fixing temperature resulted in better results, and temperatures below 140°C were set as an acceptable level.

[0262] 6-2. Uneven gloss Using the above copier, the evaluation paper used was Oji Paper's "POD Gloss Coat 128 (128g / m²)," a glossy paper. 2 The following was used: The fixing temperature was set to a temperature 25°C higher than the temperature at which under-offset does not occur (UO avoidance temperature) (UO avoidance temperature + 25°C), and the fixing roller was set to this fixing temperature. In addition, the pressure roller was set to 90°C, and the amount of toner on the transfer paper was 8.0 g / m². 2Ten consecutive solid images were output, and the gloss uniformity of the resulting images was evaluated.

[0263] The gloss uniformity of the images was evaluated by comparing the gloss of the first image and the last image (10th image) using visual inspection and observation with a magnifying glass, according to the evaluation criteria below. A rank of 2 or higher is considered acceptable and practical.

[0264] (Evaluation Criteria) Rank 4: Even when observed under a microscope at 100x magnification, no difference in gloss between the two is detectable. Rank 3: Even when observed under 20x magnification with a magnifying glass, no difference in gloss between the two is detectable. Rank 2: When magnified with a 20x magnifying glass, a slight difference in gloss between the two can be detected, but it is not detectable to the naked eye, and the image quality is at a level where there are no problems. Rank 1: The difference in gloss between the two can be detected visually.

[0265] 6-3. Evaluation of heat-resistant storage properties 0.5g of toner was placed in a 10ml glass bottle with an inner diameter of 21mm, and the lid was closed. The toner was then shaken 600 times at room temperature using a Seishin Corporation "Tap Denser KYT-2000". With the lid removed, these bottles were left for 2 hours at three temperature levels: 57.5°C, 60.0°C, and 62.5°C, and in a 35% RH environment. Next, the toner was carefully placed onto a 48-mesh (350μm opening) sieve, taking care not to break up any toner aggregates. The sieve was then set in a powder tester (Hosokawa Micron Corporation), secured with a retaining bar and knob nut, and the vibration intensity was adjusted to a feed width of 1mm. Vibration was applied for 10 seconds. After that, the percentage (mass %) of the remaining toner on the sieve was measured.

[0266] The toner aggregation rate is a value calculated using the following formula. Toner aggregation rate (%) = Mass of remaining toner on the sieve (g) / 0.5 (g) × 100

[0267] The toner coagulation rate was measured at the three temperature levels described above, and the temperature at which the coagulation rate reached 50% was estimated and defined as the 50% coagulation temperature. The heat resistance storage capacity (50% coagulation temperature) of the toner was evaluated according to the criteria described below. It was shown that a higher 50% coagulation temperature resulted in better performance, and 57.5°C or higher was considered an acceptable level.

[0268] 6-4. Liquidity Assessment The fluidity of the toner was evaluated by its bulk density. The bulk density of the toner was determined in the same manner as described in Japanese Patent Publication No. 2014-137518. That is, as shown in Figure 1 of Japanese Patent Publication No. 2014-137518, first, a 25 cm³ volume container with a circular opening of 28 mm in diameter at its upper end was used. 3 A cylindrical container was placed on a container stand set on a horizontal surface. A funnel with a 2.5 mm diameter outlet at its lower end was held by a funnel holder on a stand on the container stand, directly above the cylindrical container, at a distance of 25 mm from the opening of the container to the tip of the funnel's outlet. Next, the toner to be measured was discharged from the funnel's outlet and allowed to fall into the cylindrical container until it overflowed from the opening. After removing the raised sample portion by leveling the toner horizontally along the surface of the container's opening, the mass of the toner filled in the container was measured. From this measurement, the bulk density of the toner d (g / cm³) was calculated using the following formula (B). 3 The following was determined: It was found that a higher bulk density of toner resulted in better results, with 0.350 g / cm³ being the optimal value. 3 The above levels were considered acceptable. d = (mass of sample in container (g)) / (volume of container (cm³)) 3 )) Formula (B)

[0269] [Table 3]

[0270] The hydrophobicity rate and free silicone oil content shown in Table 3 refer to the hydrophobicity rate and free silicone oil content of the surface-treated inorganic particle with the highest mass content among the two types of surface-treated inorganic particles. Similarly, the HSP value (HSP2) of the surface treatment agent refers to the HSP value of the surface treatment agent contained in the surface-treated inorganic particle with the highest mass content among the two types of surface-treated inorganic particles. Furthermore, the content of crystalline polyester and wax refers to the ratio of the content mass when the total amount of binder resin and crystalline polyester resin (total amount of resin) is set to 100 parts by mass.

[0271] As described above, in Examples 1 to 17, which used a toner containing inorganic particles surface-treated with a surface treatment agent to achieve a hydrophobicity rate of 80% or more as an external additive, and in which the difference between the HSP value of the wax and the HSP value of the surface treatment agent was set to be greater than or equal to a predetermined value, it can be seen that both gloss uniformity and low-temperature fixation are achieved. [Industrial applicability]

[0272] The electrostatic image developing toner of the present invention achieves both low-temperature fixing properties and suppression of gloss unevenness in the resulting image. Therefore, the present invention is useful in the field of image formation.

Claims

1. Toner matrix particles having a binder resin and wax, The toner matrix particles include an external additive attached to the surface of the toner matrix particles, The aforementioned binder resin comprises a crystalline polyester resin and an amorphous resin. The aforementioned external additive contains inorganic particles that have been surface-treated with a surface treatment agent. The hydrophobicity of the inorganic particles is 80% or more. The HSP value of the wax (HSP1) and the HSP value of the surface treatment agent (HSP2) satisfy the following formula (A): Toner for developing electrostatic images. HSP1-HSP2≧2.7 Formula (A)

2. The surface treatment agent is a silicone oil. The content of free silicone oil relative to the mass of the surface-treated inorganic particles is 1 ppm to 15,000 ppm. The toner for developing electrostatic images according to claim 1.

3. The content of free silicone oil relative to the mass of the surface-treated inorganic particles is 1 ppm to 5000 ppm. The toner for developing electrostatic images according to claim 2.

4. The weight-average molecular weight of the surface treatment agent is 1,000 to 20,000. Toner for developing electrostatic images according to any one of claims 1 to 3.

5. The particle size of the inorganic particles is 10 nm to 150 nm. Toner for developing electrostatic images according to any one of claims 1 to 3.

6. The content of the crystalline polyester resin relative to the total mass of the toner matrix particles is 5% by mass to 20% by mass. Toner for developing electrostatic images according to any one of claims 1 to 3.

7. The content of the external additive relative to the total mass of the toner matrix particles is 0.3% by mass to 3.0% by mass. Toner for developing electrostatic images according to any one of claims 1 to 3.

Images